A luminance control method for an organic EL display comprises a first step of calculating a luminance accumulation value for each screen on the basis of a video input signal, and a second step of controlling the amplitude of the video input signal on the basis of the luminance accumulation value calculated in the first step and feeding to the organic EL display the video signal whose amplitude has been controlled.

Examples of organic EL displays include passive-type ones having a simple matrix structure and active-type ones using a TFT (Thin Film Transistor).
FIG. 1 illustrates the basic pixel structure of the active type organic EL display.
A circuit corresponding to one pixel in the active type organic EL display comprises a switching TFT 101, a capacitor 102, a driving TFT 103, and an organic EL element 104.
A display signal Data (Vin) is applied to the drain of the switching TFT 101 through a display signal line 111. A selection signal SCAN is applied to the base of the switching TFT 101 through a selection signal line 112. The switching TFT 101 has its source connected to the base of the driving TFT 103 and grounded through the capacitor 102.
A driving power supply voltage Vdd is applied to the drain of the driving TFT 103 through a power supply line 113. The driving TFT 103 has its source connected to the anode of the organic EL element 104. The cathode of the organic EL element 104 is grounded.
The switching TFT 101 is subjected to ON/OFF control by the selection signal SCAN. The capacitor 102 is charged by the display signal Data (Vin) fed through the switching TFT 101 when the switching TFT 101 is turned on. The capacitor 102 holds a charging voltage when the switching TFT 101 is turned off. The driving TFT 103 supplies to the organic EL element 104 a current corresponding to the voltage, held in the capacitor 102, which is applied to the base thereof.
FIG. 2 illustrates the relationship between the display signal Data (Vin) and a light-emitting luminance (a driving current) of the organic EL element 104 in the basic pixel structure shown in FIG. 1.
In FIG. 2, RefW and RefB respectively indicate a white-side reference voltage for defining a light-emitting luminance corresponding to the white level of an input signal and a black-side reference voltage for defining a light-emitting luminance corresponding to the black level of the input signal.
In the above-mentioned active type organic EL display, a large current flows through the organic EL element 104 with respect to an image which is bright on the whole screen. When the large current flows through the organic EL element 104, power consumption is increased. When the large current continues to flow through the organic EL element 104, the degradation of the performance thereof is advanced.
Therefore, a technique for detecting the current flowing into the cathode of the organic EL element 104, and controlling the power supply voltage Vdd of the organic EL element 104 in response to the value of the detected current, thereby reducing the power supply voltage to reduce a driving current when the overall screen is bright, for example, has been developed (see JP-A-2000-267628).
The control of the power supply voltage by the above-mentioned prior art is feedback control for controlling the power supply voltage Vdd of the organic EL element 104 in response to the value of the detected current. In the case of the feedback control, when the brightness of a video is rapidly changed, for example, excessive control easily occurs. In the case, a luminance varies in a short period, which is so-called "hunting".
An object of the present invention is to provide a luminance control method and a luminance control circuit for an organic EL display capable of achieving power saving as well as restraining the degradation in the performance of an organic EL element and capable of preventing "hunting" from occurring.
Another object of the present invention is to provide a portable telephone set capable of changing the display luminance of an organic EL display depending on peripheral brightness.
A further object of the present invention is to provide a portable telephone set capable of changing the display luminance of an organic EL display depending on the direction of a portable telephone set.

Organic EL display luminance control method and luminance control circuit


A coding/decoding device using a bit-precision is disclosed. A coding device includes a bit-precision selecting unit, selecting a bit-precision value according to data to be coded; and a coding unit, generating a bit-stream by coding the data according to the selected bit-precision value, whereas the selected bit-precision value is inserted into the bit-stream.

In a digital system, information is represented in a form of a binary sequence of '0' or '1,' and a plurality of binary sequences creates a meaningful information set. The meaningful information set is created in units of 8 bits, 16 bits or 32 bits according to the register size of a main processor. The unit bit is differently referred to as a word. In the information theory, the information, which consists of the information sets or is created in units of words, is referred to as an information source.
Each word constituting the information source is referred to as a symbol. Each symbol has different probability of occurrence. Once the probability of occurrence of each symbol is determined, entropy can be defined. The entropy indicates the amount of information to be stored or transferred according to Shannon's theory. If there is n symbols and the probability of occurrence of an ith symbol is pi, the entropy can be defined as the following formula 1.
                    H        =                              ∑                          i              =              1                        n                                                                                P              i                                    log                                                                          2                                      1                              P                i                                                                        [                  Formula                                                              1                ]
The entropy shows not only an average information amount per symbol but also a minimum code-length of an information source when the information source is coded. As such, the method of coding the code-length of the information source close to the entropy by using the statistical properties of symbols is referred to as entropy coding.
The entropy coding method is suggested in various ways in order to have the minimum bit number per symbol. The representative conventional entropy coding methods include a run length coding (RLC) method, a Hoffman coding and an arithmetic coding method.
The RLC method is to represent a repeated pixel block as one representative value and the repeated number of the representative value by using the fact that the sequences statistically have similar or identical values. For example, in integer data set {7, 3, 0, 0, 0, 0, 0, 0, 0} to be compressed, '0' is repeated 7 times. Accordingly, if the repeated information '0' is the representative value and the flag showing the repeated number is represented as n, the integer data set {7, 3, 0, 0, 0, 0, 0, 0, 0} is coded to be {7 3 0 N 7}. As a result, the symbols having the whole 9 byte size can be coded to be data having the 5 byte size.
Next, the Hoffman coding method is to change a constant length sign to a variable length sign. In particular, the Hoffman coding method is reduce an average sign length rather than an original sign length by allowing a short sign to be assigned to the symbol having a high generation frequency and a long sign to be the symbol having a low generation frequency. For example, an English text represented by an ASCII code employs 7 bits per letter. However, if the Hoffman coding method is applied, the English letter is represented by using the sign length of 7 bits or less on the average by allowing the letter having the high generation frequency such as "e" and "s" and to be represented with symbols of 7 bits or less and special signs having the low generation frequency to be represented with symbols of 7 bits or more.
Finally, the arithmetic coding method is to represent a variable length symbol string in which various symbols are bound as one constant length sign. The various symbols are bound such that the probability of occurrence of the symbol string can be nearly regular. In the arithmetic coding method, an input symbol is defined in a real number section between 0 and 1. The longer symbols show their narrower intervals. The bit number indicates the size of the interval. The increased number of symbols results in the smaller number of sections used to represent the symbols and the increased number of information bits for indicating the sections.
As described above, in the digital system, the computation is performed in units of words. The units of words are sets having 8 bits, 16 bits or 32 bits. As such, all numbers and letters have been represented based on units of bits. Since this conventional representing method needs more bits than bits necessary to transmit and store meaningful information, the data compression is requested for effective transmission and storage.
Typically, when a video signal including a series of video "frame" is represented in a digital form, a considerable amount of transmitted data is generated. However, since the usable frequency band width of the typical transmission channel is limited, the compression of transmission data is needed in order to transmit the considerable amount of digital data.
However, in accordance with the conventional method of compressing data or coding/decoding entropy, increasing the compression rate results in raising the complexity of the coding device or the decoding device due to their properties.
Also, the conventional method of compressing data or coding/decoding entropy brings about the time delay according to the high compression rate.

Recorded medium having program for coding and decoding using bit-precision, and apparatus thereof

Abstract: With the present invention, video data can be entropy-coded by selectively determining the number of bits and there can be provided the decoding method with a little complexity which has not only the identical compression rate to the conventional entropy coding method but also no necessity of additional computation when video data is decoded.


A pyrotechnic device contains a housing having a first end and a second end. A structural component or piston is contained within the housing. A polymer is infused into and/or about the structural component thereby accommodating the immediate ignition of the same by a known initiator/igniter in a known manner, the initiator also contained within the housing.

The present invention relates to vehicle occupant protection systems or other safety systems employing pyrotechnic devices. One such pyrotechnic device may be a linear or pyrotechnic actuator to elevate a vehicle surface such as a hood, in the event of collision or impact with a pedestrian. Known linear or pyrotechnic actuators typically employ pyrotechnic means to activate a piston within an actuator. This increases the cost of manufacturing given that the gas generating composition must typically be contained, within a micro gas generator, for example. This therefore increases the complexity of the hood lifter or seat-belt pretensioner. Additionally, typical pyrotechnic compositions may increase the size of the actuator due to storage requirements within the actuator. It would therefore be an improvement to provide an alternative to the typical pyrotechnically actuated pistons. Furthermore, it would be an improvement in the art to combine the function of at least one or more structural features of the hood lifter/seat belt pretensioner, thereby simplifying the manufacture of the pyrotechnic actuator (e.g. hood lifter or seat belt pretensioner).

Silicone propelled pedestrian hood lifter and seatbelt pre-tensioner


A system and/or method for determining human health uses a head-worn apparatus that comprises a head orientation sensor, an eye imaging device, and an electronic circuit. The head orientation sensor is configured for generating an electrical head orientation signal in response to head pitch or head yaw. The eye imaging device is configured for observing an eye feature from the sclera, cornea, iris, or pupil, and generates an eye electrical signal in response to eye position, horizontal eye movement, vertical eye movement, pupil size or eyeblinks at a plurality of times. The electronic circuit is configured for generating an ocular parameter measurement such as saccades, vestibulo-ocular reflex, vestibulo-ocular reflex cancellation, vergence, smooth pursuit, nystagmus, dynamic visual acuity, pupil size, and/or eyeblinks from the head and eye electrical signals. The ocular parameter measurement can be used to determine normal human health, a neurologic disorder, a biochemical health impairment, or a physiologic health impairment.

Eye and head tracking, can have significant value in determining human health such as concussions (traumatic brain injury), vision impairment, neurocognitive disorders (NCD), alertness, and fatigue. Eye movement responses can also indicate physiologic and biochemical impairments such as impairments due to alcohol and drugs.
Historically, human health status has been diagnosed in a clinical setting. New sensors and electronic technologies enable the development of portable systems for non-clinical environments. Such advancements facilitate increases in speed and accuracy for eye and head movement observations to measure ocular parameters such as saccades, vestibulo-ocular reflex (VOR), vestibulo-ocular reflex cancellation (VORC), vergence, smooth pursuit (SP), nystagmus, dynamic visual acuity (DVA), pupil size, and/or eyeblinks. These ocular parameter measurements can more effectively determine human health status.
Human health status. It has been demonstrated that neurologic disorders, such as traumatic brain injury, microvascular ischemic disease, stroke, Alzheimer's disease, and Parkinson's disease can produce measurable changes in one or more of the following ocular parameters: VOR, saccades, smooth pursuit, vergence, nystagmus, and/or pupillometry. It has also been demonstrated that biochemical health impairments including alcohol and drug use, electrolyte, and hormone deficits (associated with dehydration, renal failure, and diabetes), and pulmonary deficits (resulting in hypercapnia or hypoxia), can cause measurable changes in one or more of the following ocular parameters: VOR, saccades, smooth pursuit, dynamic visual acuity, vergence, pupillometry, and/or eyeblinks. Additionally, it has been demonstrated that physiologic health impairments such as alertness/fatigue, spatial disorientation, vertigo, motion sickness, effects of electromagnetic waves due to exposure, and cardiac hypotension can cause measurable changes in one or more of the following ocular parameters: pupillometry, saccades, VOR, nystagmus, and smooth pursuit. Thus, having a portable device that can be used in a non-clinical environment for measuring one or more of the above ocular parameters would be highly beneficial. Each of the aforementioned human health detriments can affect different areas of the neurologic system and each of the ocular parameters to be measured can assess different anatomical regions and neural pathways of the brain. Human health status and certain health disorders or impairments may be more accurately detected by different ocular parameter measurements or by using a combination of ocular parameter measurements.
For example, the vestibulo-ocular reflex maintains eye fixation during head rotation. It is the head rotation that generates this reflex. Measurement of this reflex assesses the neural pathway response from the inner ear balance structures (e.g., utricle, saccule, semicircular canals) to the vestibular nerves, the vestibular nucleus in the brainstem (medulla and pons), and cranial nerves III, IV and VI, which move the extraocular muscles. The superior branch of the vestibular nerve innervates the lateral semicircular canal, anterior canal, and utricle. The inferior branch innervates the posterior semicircular canal and saccule. It is important to assess VOR function of each individual semicircular canal, as different impairments can affect different semicircular canals. For example, TBI can affect one semicircular canal function and not the others. Other less thorough studies, such as rotary chair testing or videonystagmography, evaluate only the function of the lateral canal. Measuring each of the semicircular canals as described herein at varying frequencies, particularly between 2 and 10 Hz is much more representative of natural head movements and can provide more information regarding impairments affecting the inner ear (e.g., vestibular, or labyrinthine impairments).
Smooth pursuit another ocular parameter, is a voluntary eye movement which requires attention on a moving visual target. It is designed to keep a moving visual target on the fovea, the region in the retina of the eye where visual acuity is highest. The goal of the smooth pursuit system is to generate eye velocities that are like the target speed, as the target is tracked. Visual information from the retina is transmitted to the middle temporal area (MT) and from this area motion signals are transmitted through the parietal sensory-motor cortex to the smooth eye movement region of the frontal eye fields (FEF) in the frontal lobe of the brain. From these 3 areas, the MT, the parietal sensory-motor cortex, and the FEF, signals are transmitted through a variety of brainstem relay nuclei to at least two regions of the cerebellum, the oculomotor vermis and the floccular complex. From these areas, signals are then relayed to the vestibular nuclei in the brainstem and lastly project to the extraocular muscles, to move the eyes.
Saccades represent another ocular parameter and are described as rapid conjugate eye movements that are under both voluntary and reflex control. Saccades are mainly used for orienting gaze towards a visual object of interest or target. The eyes execute a series of very rapid movements from one point to another, stopping briefly at each point, the fixation point, to assess the visual image. Examples of voluntary saccades are self-directed eye movements in response to skimming a text. The sudden appearance of a peripheral visual object or an abnormal sound may evoke a reflex saccade in the direction of the stimulus. Visual information from the retina generates a signal which is sent to the primary visual cortex in the occipital lobe of the brain. Signal information is then sent to the frontal eye fields (a region in the frontal lobe), the parietal cortex and the superior colliculus of the midbrain. The superior colliculus activates the horizontal and vertical brainstem gaze centers in the pons. The horizontal gaze center and the sixth nerve nucleus allows for coordinated abduction and adduction of the eyes to shift within the horizontal axis by movement of the lateral rectus and medial rectus muscles. The vertical gaze center is in the rostral part of the midbrain which sends signals to the nuclei in the pons, which subsequently provides movement of the superior oblique, inferior oblique, superior rectus, and inferior rectus muscles. Activation of the horizontal and vertical gaze centers in concert allows for oblique eye movements. The frontal eye field of one hemisphere controls voluntary saccadic eye movements that are directed toward the contralateral visual hemifield (i.e., the right frontal eye field directs the eyes to the left).
Pupillometry is another ocular parameter, which is used to record and measure reactions of the pupil, such as size, position and movement with minute fluctuations seen in response to a stimulus. The pupillary light reflex constricts the pupil in response to light, and pupillary constriction is achieved through the innervation of the iris sphincter muscle. Light reaching the retina is converted into neuronal signals. Information travels through the optic nerve, then goes through the optic chiasm to reach the pretectal nucleus in the midbrain, where it communicates with parasympathetic nuclei in the midbrain called Edinger-Westphal nuclei, which controls the efferent pupillary pathway. Efferent parasympathetic fibers travel via the oculomotor nerve to directly innervate the iris sphincter muscles. The contraction of the iris sphincter muscles leads to pupillary constriction (miosis). It is also at the optic chiasm that some nerve fibers cross to the contralateral side of the optic tract. As a result of the crossing fibers, there is not only a direct pupillary reflex but also a consensual pupillary light reflex. The pupillary dilation pathway is a sympathetically driven response to stimuli and is a three-neuron pathway. The first-order neuron begins in the hypothalamus and descends to the spinal cord in the lower cervical area and upper thoracic area. The second-order neuron exits the spinal cord and ascends through the thorax onto the superior cervical ganglion. The superior cervical ganglion, a third-order neuron, enters the orbit via the ophthalmic division of the trigeminal nerve and ends on the dilator pupillae muscle, causing pupillary dilation.
Eye observation. As mentioned previously, ocular parameters can be measured from observations of eye and head information. Observed eye and eyelid information of interest can include horizontal eye movement (left-right when seen from the front), vertical eye movement (up-down when seen from the front), rotation of the eyes (when seen from the front), eye position, pupil size and movement, and eyeblinks. It is desired to use a system and/or method for observing these eye parameters that is as accurate, repeatable, responsive to higher frequencies, portable, and low cost as possible. In the past, non-imaging technologies, such as detectors that used scleral coils, placed on the eye have also been used. More recently, imaging technologies that detect light information reflected off the eye and convert this light information to electrical information have become the most common technologies for eye and eyelid observation. Such imaging technologies typically have a light source and a photodetector or photodiodes. The light source can be monochromatic or polychromatic, it can be ambient or generated by the device, it can be visible, or at a wavelength that is shorter than visible (ultraviolet) or longer than visible (infrared), it can be a focused and directed beam or multidirectional. Examples of imaging technologies can include video cameras that use an array of photodetectors (typically charge conducting devices known as CCDs), video cameras that scan a beam onto an image and sense this with a photodetector (such as the broadcast video cameras in common use from the 1930s to the 1990s), and scanners that direct a beam at the eye that is then sensed with a photodetector. Imaging of the eye can be used to determine information such eyeblinks, the location and size of the pupils, and/or the location of the cornea or other eye feature being measured at any time. This location information can determine gaze and eye closure. By taking multiple successive location readings at successive times, it is possible to determine movement of the eye or eyelid as a function of time. It is desirable to have this eye and/or eyelid movement information at fast enough rates to accurately resolve human physiological behavior such as eyeblinks (which can occur at a mean rate of 17 blinks per minute when resting, 26 blinks per minute in conversation and as low as 4 blinks per minute when reading) and saccades, which can occur at a rate of 900 degrees/second and involved movements of only 0.1-0.5 degrees and generally 0.1 degree in the case of microsaccades.
Head observation. The described eye observations can be combined with head observations to determine ocular parameters such as VOR, DVA, VORC, nystagmus, SP, saccades, and dynamic vergence with combinations of other ocular parameters. The primary head observations of interest are pitch, which is movement of the head up and down when looked at from the front, and yaw, which is a side-to-side movement of the head when viewed from the front. The third rotation that is sometimes of interest is roll, as rotation of the head when looked at from the front. Such head rotations can easily be observed using an inertial measurement unit (IMU), which can comprise one or more accelerometers, gyroscopes, and magnetometers. Other systems and methods for observing head position and/or movement can use optical (including infrared), acoustic, ultrasonic, and laser technologies.
It is desired to overcome some of the following challenges of prior art systems and methods that use eye and head observations to assess human health status:                (a) Achieving a sufficiently high scan rate (also known as frame rate) so that high frequency movements (such as microsaccades) are captured;        (b) Accuracy and resolution of the detected eye and head position and movement;        (c) Portability;        (d) Power consumption;        (e) Cost; and        (f) Ability to be operated and used with minimal or no training.
The potential benefits of devices described herein is that they can change the standards of care and clinical recommendations by optimizing rapid evaluation and treatment. Since ocular parameters assess different areas of the central nervous system and different factors of the human health status, such systems and methods can function as physician extenders by detecting abnormalities, monitoring the recovery process, and establish rehabilitation programs to more rapidly recover from an abnormal ocular parameter detected. The technology can be applicable to any head-worn platform (i.e., apparatus), such as a see-through device (helmet, glasses, face shield, augmented reality, etc.), a virtual reality device, or any related technology. Such systems and methods could determine the human health status, detect a health disorder or impairment, define the characteristics of the deficit, quantify the deficit, and wirelessly transmit this information to the wearer of the device, and/or remotely. If an abnormal ocular parameter is noted for users participating in contact sports or military personnel participating in remote areas, not only can a rehabilitation program begin earlier but an accurate monitoring strategy for decisions regarding the need for extraction or returning to play or deployment be determined. Mobile testing for clinics, hospitals, emergency departments, law-enforcement environments, urgent care centers, school facilities, on-the-field locations, or in remote areas can provide greater access for evaluation of the human health status because of its portability, lower expense, scalability, and availability of rapid and accurate results for larger numbers of individuals.
It should be understood that the drawings are not necessarily to scale. In certain instances, details that are not necessary for an understanding of the invention or that render other details difficult to perceive may have been omitted. It should be also understood that the invention is not necessarily limited to the embodiments illustrated herein.

Systems and methods for observing eye and head information to measure ocular parameters and determine human health status


Nanofibres are provided that are insoluble and swellable in an essentially aqueous effluent, a method for the preparation of these nanofibres and the use of these nanofibres for the extraction from an effluent of metals, in particular metal salts originating from heavy metals, of rare earths, alkali metals, alkaline earth metals or actinides, in the stable or unstable isotopic forms thereof.

The present invention relates to polymer nanofibres that are swellable and insoluble in an essentially aqueous effluent and use thereof in the treatment of these effluents.
The pollution of water by heavy metals has been an increasing environmental problem over the last few decades, requiring immediate and urgent action.
Heavy metals, such as Zn, Co, Fe, Cr and Cu, are widely used in the surface treatment industry, in connection with the automotive sector or microelectronics, for the implementation of electroplating, electroless or electrogalvanizing processes. Despite technical advances, the liquid effluents discharged by these industries inevitably always contain traces of heavy metals, mainly in the form of salts, which are dangerous to public health and the environment and require treatment before being discharged into the environment.
The European standards regulating the levels of the different elements discharged are now becoming increasingly strict. In the case of heavy metals such as copper, the discharge authorization threshold for the standard effluents has been reduced from 2 mg/L in 1985 to less than 0.5 mg/L since 1998, when the daily discharge quantity exceeded 5 g/day.
The nuclear industry also needs to address the issue of the treatment of liquid effluents contaminated with radioactive elements, which can be produced during decontamination operations or in the event of accidents. For example, the Fukushima disaster made vast quantities of seawater radioactive due to the presence of radioactive caesium. This resulted in thousands of cubic metres of seawater having to be treated in order to remove traces of radioactive caesium. The difficulty is to capture the caesium atoms present in very low concentrations, from 10−7 to 10−12 mol·L−1, among sodium atoms, which are at least 1000 times more concentrated.
In the case of the rare earths, in addition to concern for public health and the environment, the recovery and separation of these elements from an effluent is also of considerable economic significance. In fact, the rare earths are used in significant quantities in high-technology products and, on account of their strategic nature and supply difficulties, their recycling is becoming very attractive.
Consequently, the treatment of industrial liquid effluents is becoming a major problem in our society. Currently in industry, in particular in the surface treatment, electronic, or nuclear industries, there is a specific demand for novel processes that are cleaner, inexpensive and able to come down to a performance threshold up to ten times lower than the current standards.
Most conventional methods for the treatment of effluents comprise a primary treatment followed by a secondary treatment. The primary treatment implemented by coagulation and/or precipitation makes it possible to remove the different solid pollutants. If this treatment also makes it possible to reduce the metals present in an effluent by 90% to 95%, it does not always make it possible to meet the requirements of the standards. It is necessary to use a secondary treatment in order to further reduce the heavy metals content.
The following conventional methods that can be used for a secondary treatment may be mentioned as examples: ion-exchange resins, membrane filtration, liquid-liquid extraction. Some of these are fairly effective, but unfortunately have inherent limits such as rigorous operating conditions and the production of secondary contaminants.
Ion-exchange resins are widely used for treating effluents containing heavy metals and have numerous advantages: their treatment capacity, a certain metal capture selectivity and their rapid kinetics compared with other, for example membrane, techniques. Most resins are constituted by very small synthetic polymer beads (50-500 μm) between which the effluent passes in order to be decontaminated. The effectiveness of these resins is however limited due to their design. In fact, the vast majority of resins reach only 50% of their exchange capacity due to their manufacture which requires chemical functionalizations that have not taken place at all the potentially accessible sites. On the other hand, the ion-exchange resins are especially effective at their periphery where the exchange can take place rapidly. As diffusion of the liquid in solid phase is very slow, diffusion channels are designed in the manufacture of these resins in order to improve the penetration of the effluent into the core of the resin beads. Nevertheless the diffusion of the liquid deep in the resins is still slowed and this contributes to reducing the useful capacity of the resins. It would be possible to compensate for this problem by drastically reducing the diameter of the beads in order to reduce the surface/volume ratio. However, problems of pressure loss (clogging) and risks presented by their powdery nature will then become apparent.
Another major drawback of this technique is the need to use large quantities of concentrated acids and bases in order to carry out the regeneration operations. It is acknowledged that the regeneration of a kilogram of ion-exchange resins can require the use of more than 50 litres of acids and/or of bases which become secondary effluents. It is important to minimize these secondary effluents.
Another technology developed in the last twenty years consists of using membrane techniques, such as microfiltration, nanofiltration, ultrafiltration and reverse osmosis. However, at present, these techniques are rarely used in the separation of metals, as the membranes can be mechanically fragile and do not have properties of selectivity vis-à-vis metals. Moreover, these techniques consume a great deal of energy.
More recently, natural fibres, such as fibres originating from cotton, fungi, cacti, and waste from food-producing agriculture have been used for the filtration and extraction of metals. The manufacture of these fibres is very cost-effective, but their performance and especially their selectivity remain very modest. For example, the performance of a membrane obtained from a mixture of natural cotton and silk fibres in order to capture copper is only 2.88 mg/g (Ki et al., 2007, Membrane Sci., 302, 20).
The latest technological development consists of using nanofibres, which have micrometric or submicronic diameters and are manufactured either by electrospinning of a polymer solution under high voltage or by application of a centrifugal force (centrifugal spinning) to a polymer solution. However, the industrial use of these nanofibres, often in membrane form, at present remains within the field of tissue engineering or as super-absorbent materials, or also for carrying out mechanical filtration.
To date, several scientific publications have discussed the application of membranes of nanofibres obtained from different polymers for capturing metal ions in solution. However, the performance of these membranes is not satisfactory and does not allow large-scale productivity.
Ignatova et al. (Macromol. Rapid Commun. 2008, 29, 1871-1876) describe the use of nanofibres of polystyrene associated with calixarenes for capturing nickel. No capture capacity is mentioned in this article. The polystyrene is recognized as being very hydrophobic and not very swellable in water.
Numerous publications are also to be found concerning fibres of polyacrylonitrile or derivatives thereof. (F. Huang, Materials 2013, 6, 969-980). Polyacrylonitrile is also recognized as being not very hydrophilic and therefore not very swellable in water.
Wang et al. (J. Membr. Sci. 2011, 379 191-199) have analysed a membrane obtained by electrospinning from a solution of polyvinyl alcohol (PVA) and polyethylenimine (PEI). Its capacity for capturing copper is 67.16 mg/g. However, the regeneration of this membrane requires either very strong acid or basic solutions or a powerful and toxic organic complexing agent, such as EDTA. Moreover, these polymers are not sufficiently hydrophilic for the treatment of substantially aqueous industrial effluents.
Xiao et al. (J. Appl. Polym. Sci., 2010, 116, 2409) have described a membrane obtained by electrospinning from a solution of polyacrylic acid (PAA) and polyvinyl alcohol (PVA). Its copper capture performance is approximately 10 mg/g and is therefore still very low. The incorporation of PVA into the initial polymers reduces the hydrophilic properties of the nanofibres, limiting the solubilization of the PAA.
Li and Hsieh (Polymer 2005, 46, 5133) have described the possibility of cross-linking a pure PAA nanofibre with beta-cyclodextrins. The authors chose to react the alcohol functions of the cyclodextrins with the anhydride functions of the PAA which are formed by annealing at 140° C. However, the permeability of this material is not sufficient, as the cyclodextrin content of approximately 30% remains high. Moreover, the tests for this material were carried out in an acid aqueous medium of pH 2-7 and over a maximum period of 24 h. This range of pH has no technical benefit in the field of retreatment of metals with PAA, as the latter acquires its complexing form in basic media.
As an alternative to electrospinning, techniques based on centrifugal force (centrifugal spinning) have recently been developed, such as for example, the FORCESPINNING® technique (Sarkar et al., Materials Today, 2010, 13(11), p 12-14). However, to date nanofibres obtained by this technology have not been used in the separation of ions in solution.
The nanofibres described in these previous publications cannot be used on an industrial scale for extracting and separating the metals because, on the one hand, they are not sufficiently hydrophilic in a substantially aqueous effluent and do not have a satisfactory capacity or specificity for capturing the metals and, on the other hand, they additionally require a very long capture or regeneration time.
In response to this problem, there is very strong interest in developing nanofibres which have a very high water-permeability and which do not dissolve. In order to improve the properties of these nanofibres vis-à-vis metal targets that are difficulted to extract or interfered with by elements of little interest, these nanofibres will be able to contain complexing molecules having very specific capture properties.

Swellable and insoluble nanofibers and use thereof in the treatment of essentially aqueous effluents

COMMISSARIAT A L'ENERGIE ATOMIQUE ET AUX ENERGIES ALTERNATIVES


A robotic lawnmower system, comprising a robotic lawnmower and a charging station, said charging station comprising a signal generator being configured to transmit a boundary signal (A) utilizing CDMA coding having a frame length corresponding to a full frame length through a boundary wire, wherein said signal generator is configured to transmit said boundary signal in subframes, and wherein said robotic lawnmower is configured to receive said boundary signal by detecting magnetic fields generated by the boundary signal, and wherein the robotic lawnmower is configured to determine a set of conditions; and to determine if said set of conditions correspond to a first set of conditions, and if so listen to the subframes, and to determine if said set of conditions correspond to a second set of conditions, and if so listen to the full frames.

Automated or robotic power tools such as robotic lawnmowers are becoming increasingly more popular. In a typical deployment, a work area, such as a garden, is enclosed by a boundary cable with the purpose of keeping the robotic lawnmower inside the work area. The robotic lawnmower is typically also configured to communicate with a charging station located in the work area and connected to the boundary cable.
Using standardised coding such as Gold codes, has the obvious advantage that new coding schemes need not be invented. However, the inventors have realized that the frame length commonly used for CDMA coding, such as Gold coding, when used with technology commonly used for lawnmower systems leads to a transmission time for the entire frame that is in the order of seconds, such as 1 second, 0.5 seconds or up to 0.5 seconds. Such time spans may be unpractical in real life implementations as a robotic lawnmower operating using such time frames would move a distance that could not be neglected before being able to decode the entire frame. The robotic lawnmower may thus be rendered unable to detect whether it is still within the work area or not.
This would for practical reasons render gold coding inoperable for robotic lawnmower systems. To overcome this, the inventors realized that by dividing a frame as per above, shorter segments of the entire frame, i.e. sub frames, may be used to control the robotic lawnmower.


A radio frequency (RF) receiver circuit is disclosed. The RF receiver circuit includes a variable gain amplifier, configured to receive an input RF signal, and to generate an amplified RF signal based on the input RF signal, where a gain of the variable gain amplifier is variable. The RF receiver circuit also includes an RF level indicator circuit, configured to sample the amplified RF signal at non-periodic sampling intervals to generate a plurality of sampled RF signals, and to compare the sampled RF signals with one or more thresholds to generate a plurality of comparison result signals. The gain of the variable gain amplifier is determined based at least in part on the comparison result signals.

Receiver circuits having LNA circuits with variable gain suffer as a result of, for example, blocker signals which may cause the outputs of the LNA circuits to saturate. Receiver circuits having insufficient ability to sample LNA output correctly control the gain of the LNA circuit improperly, resulting in either inadequate LNA gain, which increases noise in the receiver output, or excessive gain, which causes clipping in the LNA output.


An analyzer performs spectral analysis of a characteristic parameter of an input speech signal per unit time so as to calculate, as a recognition parameter, orthogonal expansion of a spectrum of the analyzed characteristic parameter. A formant frequency of the input speech signal is detected, and a compensation value is calculated for the recognition parameter using the formant frequency. The recognition parameter is compensated in accordance with variations of the input speech signal caused by a noisy environment using the compensation value. The compensated recognition parameter is compared with reference parameters to output a recognition result.

The present invention relates to a speech recognizer.
In response to recent developments in speech recognition technology, speech recognizers are almost ready to be put to practical use in various fields. However, in order to achieve such practical use of speech recognizers, many problems must yet be solved.
In actual use, the operating states in which the speech recognizers are used vary, thus causing variations in the voice patterns of speech to be recognized. For example, when background noise in the vicinity of the speech recognizers becomes significant, a speaker must speak loudly, thereby resulting in variations in voice patterns. Such variations in voice patterns caused by a speaker attempting to overcome a noisy environment are called the "Lombard effect". The voice patterns also vary when the speech recognizers are used for a long time and the speaker becomes tired. Furthermore, when the speakers themselves are changed, the voice patterns vary.
Therefore, if a state in which a speech recognizer has learned a reference voice pattern is different from a state in which the speech recognizer is used, a serious problem arises in that the reference voice pattern cannot account for the above mentioned variations in voice patterns, thereby resulting in erroneous speech recognition.
In order to solve this problem, a countermeasure is employed in which the speech recognizer is made to learn all foreseeable voice pattern variations in advance. However, such is not practical in that the learning time and capacity of the speech recognizer must be increased enormously and the operator must perform extremely troublesome operations.
Thus, in recent years, a method has been proposed in which voice pattern variations are calculated each time the speech recognizer is used and analytical conditions are changed in accordance with the voice pattern variations at the time of analyzing characteristic parameters of voice pattern variations. By employing this method, voice pattern variations can be accounted for using a shorter learning time and smaller speech recognizer capacity and requiring a lesser burden on the operator.
Hereinbelow, a known speech recognizer is described with reference to FIG. 1. The known speech recognizer is of a registration type in which the reference voice pattern is made by inputting the voice of a user. As one example in which voice patterns at the time of storing a reference voice pattern and at the time of voice pattern recognition differ from each other, a case where noise in the surrounding environment varies is adopted. In FIG. 1, the known speech recognizer includes a signal input terminal 1, a power measuring portion 20, analyzers 21 and 23, a vowel deciding portion 22, a matching portion 8, and output terminal 9 for outputting a recognition result, a buffer 10 for storing the reference voice pattern and switches 24, 25 and 26.
The known speech recognizer of the above described arrangement is operated as follows. Initially, at the time of storing the reference voice pattern, environmental noise in the vicinity of the speech recognizer, immediately before the input of the reference voice signal, is input to the signal input terminal 1 and the power level of the environmental noise is calculated by the power measuring portion 20. If the power level of the environmental noise exceeds a predetermined threshold value P1, the environment is regarded as being unsuitable for storing of the reference voice pattern and thus, registration of the reference voice pattern is suspended. On the contrary, if the power of the environmental noise is not more than the threshold value P1, a reference voice pattern signal is input to the signal input terminals 1 and is fed to the analyzer 21 where a characteristic parameter is calculated. At this time, the input signal is passed through a filter F1 expressed by the following equation (i). EQU F1(z)=1-0.9375.times.Z.sup.-1 (i)
In the equation (i), character Z denotes the Z-function of the FFT (fast Fourier transformation) X(f) for transforming a time function into a frequency function. Assuming that character t denotes time and character f denotes frequency, the FFT X(f) is given by: ##EQU1## where exp(-j2.pi.ft) is expressed by the Z-function Z, i.e. Z.ident.exp(-j2.pi.ft).
After a high-frequency band of the input signal has been emphasized by the filter F1, the input signal is analyzed. If the LPC cepstrum method is carried out in the analyzer 21, a predetermined number of LPC cepstral coefficients are calculated as characteristic parameters. When the Dower level of the voice pattern exceeds a detection threshold value within a predetermined voice pattern interval, the corresponding characteristic parameter is regarded as the reference voice pattern to be stored in the buffer 10. The above described processing starting from the input of the reference voice pattern signal is performed for all words to be recognized and the registration process is then complete.
Subsequently, at the time of speech recognition, the power level of environmental noise is measured in the same manner as in the reference voice pattern registration process and then, a voice signal is input via the signal input terminal 1. If the power level of the environmental noise is not more than the threshold value P1, a characteristic parameter of the input voice signal is calculated using the analyzer 21 in the same manner as in the registration process, and the thus calculated characteristic parameter is transmitted to the matching portion 8. At the matching portion 8, the variations between the reference voice patterns and the input voice pattern is calculated and a word exhibiting a minimum variation is output as a recognition result from the output terminal 9.
On the other hand, if the power level of the environmental noise exceeds the threshold value P1, the power level of the input voice signal is calculated for each frame by the power measuring portion 20 and then, the power level of the environmental noise and the power of the input voice signal are fed to the vowel deciding portion 22. At the vowel deciding portion 22, a vowel determination is made based on the following conditions (a) and (b).
(a) The signal level is higher than a sum of the noise level and a constant C.
(b) Five or more continuous frames satisfying the above condition (a).
It is determined that a frame which satisfies the conditions (a) and (b) is a vowel. If a frame is not determined to be a vowel, the input signal is fed to the analyzer 21, a high-frequency band of the frame is emphasized using the filter expressed by the above equation (i) and the characteristic parameter is calculated in the same manner as in the case of the reference voice pattern registration process. On the other hand, if a frame is so determined to be a vowel, the input signal is fed to the analyzer 23, a high-frequency band of the frame is emphasized by a filter F2 expressed by the following equation (ii). EQU F2(Z)=1-0.6375.times.Z.sup.-1 (ii)
The emphasis of the high-frequency band of the frame by the filter F2 is less than that of the filter F1 and the tilt of the equation (ii) is milder than that of the equation (i). When environmental noise becomes large, the voice state of a speaker changes such that a high-frequency band of the input voice signal becomes intense. Therefore, the tilt of a filter for emphasizing a high-frequency band in a noisy environment is required to be milder than that in a less noisy environment. After the input voice signal has been passed through the filter F2, the characteristic parameter thereof is calculated in the same manner as in the reference voice pattern registration process.
The calculated characteristic parameter is fed to the matching portion 8 and the recognition result is generated from the output terminal 9 in the same manner as in the case where the power level of the environmental noise is not more than the threshold value P1.
The switch 24 actuates to changed over to the vowel deciding portion 22 and to the analyzer 21 when the power level of the environmental noise exceeds the threshold value P1 and is not more than the threshold value P1, respectively. When no voice signal is being input, the switch 24 is in an OFF state. The switch 26 actuates to changed over to the analyzer 23 and to the analyzer 21 when the frame is determined to be a vowel and is not determined to be a vowel, respectively. Meanwhile, the switch 25 actuates to change over to the buffer 10 and to the matching portion 8 during the reference voice pattern registration process and voice recognition process, respectively.
In the above described known speech recognizer, changes in spectral tilt due to variations of voice patterns are initially compensated for, and then the parameter used for recognition of a voice signal is analyzed. Thus, the known speech recognizer suffers drawbacks in that, since the contents of the compensation are not accurately incorporated into the parameter through the analysis processing, the compensation efficiency is reduced and in some cases, the compensation does not contribute to an improvement of the recognition rate at all.
Furthermore, the known speech recognizer is disadvantageous in that, although it is possible to compensate for changes in spectral tilt, it is not possible to compensate for changes in the resonance frequency characteristic of a vocal sound (referred to as "formant frequency", hereinbelow) caused by variations of voice patterns, thereby resulting in a lowering of the recognition rate.

Lombard effect compensation using a frequency shift

Matsushita Electric Industrial Co., Ltd.


A cooling energy generator with a cooling energy accumulator comprises a refrigerant, absorbent liquid, and a container having a first chamber receiving the absorbent liquid, a second chamber receiving the liquid refrigerant and a vapor passage communicating with a space over the absorbent liquid in the first chamber and with a space over the liquid refrigerant in the second chamber. The absorbent liquid is sprayed in the first chamber, and the absorbent liquid is cooled during an accelerated cooling operation. The absorbent liquid is heated during the cooling energy accumulation operation, and liquid refrigerant is sprayed in the second chamber during the accelerated cooling operation and during the normal cooling operation. An air conditioning heat exchanger supplies the cooling energy to a cooling device for air conditioning, and a heat pump is provided. The cooling energy generator with the cooling energy accumulator continues to generate cooling energy for normal air cooling without any additional device even when the refrigerant is not absorbed by the absorbent because the refrigerant is circulated in the second chamber to generate the normal cooling energy.

The present invention relates to a cooling energy generator for air conditioning and, more particularly, to a cooling energy generator with a cooling energy accumulator effective in decreasing required electric power during the accelerated cooling operation.
In the Japanese Unexamined Patent Publication No. 62-218773, a prior-art cooling energy accumulator is disclosed including four heat exchangers, with two of the heat exchangers being incorporated within a closed circuit of compressing-type heat pump, and the other two heat exchangers of being respectively incorporated within an air-conditioning circuit and a refrigerant-liquefying circuit.
As shown in FIG. 7, when the cooling energy is stored in the accumulator, a heat-pump refrigerant gas (for example, Freon gas) is compressed by a compressor 1 so that the temperature of heat-pump refrigerant gas is increased. The compressed high-temperature heat-pump refrigerant gas flows in a first heat exchanger 4 in a closed container 23 to heat an absorbent sprayed on the outer surface of the first heat exchanger 4. The absorbent includes a refrigerant. The refrigerant evaporates from the absorbent heated on the outer surface of the first heat exchanger 4, so that the absorbent is concentrated. The concentrated absorbent is stored in a bottom of a first chamber. The heat-pump refrigerant gas cooled by the evaporating refrigerant condenses and liquefies in the first heat exchanger 4. The heat-pump refrigerant subsequently passes through an orifice 18 for adiabatic expansion so that the temperature of heat-pump refrigerant is decreased. The cool heat-pump refrigerant flows into a second heat exchanger 5, and the refrigerant vapor generated on the first heat exchanger 4 flows through a vapor passage 25 into a second chamber in which the second heat exchanger 5 is arranged. The refrigerant vapor condenses and liquefies on the cool outer surface of the second heat exchanger 5. The liquefied refrigerant is stored in the bottom of the second chamber.
When the cooling energy accumulator generates cooling energy, the accumulator operates as follows. At first stage, heat exchangers 26 and 27 arranged in the container 23 are used, but the heat exchangers 4 and 5 are not used at this stage. The concentrated absorbent stored in the bottom of the first chamber is sprayed on the outer surface of the heat exchanger 26 from a spray device 30. A cooling liquid flows in the heat exchanger 26 so that the absorbent is cooled by the heat exchanger 26 and absorbs the refrigerant vapor. Since the refrigerant vapor is absorbed by the absorbent, the pressure in the container 23 decreases. The refrigerant stored in the bottom of the second chamber is sprayed on the outer surface of the heat exchanger 27 from a spray device 31. The sprayed refrigerant evaporates at the saturation temperature corresponding to the pressure existing in the container 23. When the refrigerant evaporated, the refrigerant absorbs a latent heat. The cooling liquid flowing in the heat exchanger 27 is cooled by the latent heat and the cooling liquid is used for air conditioning. The refrigerant vapor absorbing the latent heat is absorbed by the absorbent, so that the concentration of the absorbent decreases. When the concentration of absorbent decreases under a certain level, the absorptivity of absorbent for absorbing the refrigerant vapor decreases, so that the pressure in container increases. The increase of pressure in the container makes the evaporation of refrigerant for generating the cooling energy insufficient. Therefore, in second stage, the heat pump is operated as follows. The compressed high-temperature and high-pressure heat-pump refrigerant flows in the direction opposite to the direction described above. The compressed high-temperature and high-pressure heat-pump refrigerant is cooled in a radiator 6 and subsequently passes through the orifice 18 for adiabatic expansion so that the temperature of heat-pump refrigerant further decreases. Then, the cooled heat-pump refrigerant flows into the heat exchanger 4. Therefore, the refrigerant vapor is condensed and liquefied on the heat exchanger 4. Since the pressure in the container 23 is decreased with the condensation of refrigerant vapor, the evaporation of refrigerant liquid sprayed on the heat exchanger 27 becomes possible again, so that the air conditioning can be continued.

Cooling energy generator with cooling energy accumulator


A power retractable trailer hitch for a vehicle can include a hitch assembly movably coupled to an external case or support member, and a power actuator engaging the hitch assembly. The power actuator can be operable to move the hitch assembly between a retracted position and an extended position. A controller can be operable to control activation of the power actuator. An interlock can be provided requiring a transmission of the vehicle to be in a parked position before the controller can be operable to move the hitch assembly between the retracted position and the extended position. A locking member can be operable by the controller to move between a locked position and a released position with respect to the hitch assembly. The locking member can be operable to be in a locked position, when the hitch assembly is in at least one of the extended position and the retracted position, and in a released position, when the hitch assembly is in transition between the extended position and the retracted position.

Various configurations of manually retractable trailer hitch assemblies can be seen in U.S. Pat. Nos. 6,511,090; 6,189,910; 5,431,425; U.S. Patent Application Publication No. US-2004/0075243; and U.S. Patent Application Publication No. US-2005/0161904. While these devices appear to be suitable for their intended purpose, it would be desirable to provide a power actuator operable to move the hitch assembly between a retracted position and an extended position. It would be desirable to provide a controller operable to control the power actuator. It would be desirable to provide an interlock requiring a transmission of the vehicle to be in a parked position before the controller can be operable to activate the power actuator for controlling movement of the hitch assembly between the retracted position and the extended position. It would be desirable to provide a locking member or pin operable by the controller to be in a locked position when the hitch assembly is in at least one of the extended position and the retracted position, and to be in a released position when the hitch assembly is in transition between the extended position and the retracted position. It would be desirable to provide a user switch having at least a hitch-retract position and a hitch-extend position operable to control the power actuator for controlling movement of the hitch assembly between the retracted position and the extended position. It would be desirable to provide an end-of-travel sensor in communication with the controller and located adjacent at least one end of the support member corresponding to at least one of the retracted position and the extended position of the hitch assembly. It would be desirable to provide any of the features described above in any combination.

Nissan Technical Center North America, Inc.


A pad structure is suitable for a circuit carrier or an integrated circuit chip. The pad structure includes an inner pad, a conductive via and an outer pad. The conductive via connects the inner pad. The outer pad connects the conductive via and further connects a conductive ball or a conductive bump. The outer diameter of the outer pad is greater than the outer diameter of the inner pad.

1. Field of the Invention
The invention generally relates to a pad structure, and more particularly, to a pad structure used in a circuit carrier or an integrated circuit chip for connecting a conductive ball or a conductive bump.
2. Description of Related Art
In the electronic industry, soldering is a major connecting technology, for example, used for flip chip bonding between a chip and a carrier or connection between a common electronic part and a circuit board. For bonding process, in addition to solder, pad itself and pad surface material, a pad structure plays a critical role to affect bonding reliability.
The multiple functions and miniature of a chip have become a tendency of electronic products, which accordingly requires an increased density of contacts. Under the above-mentioned situation, for some signals with a specific electrical requirement (for example, low impedance, high frequency, coupling sensitivity and the like), the line width and line of the chip need to be increased, which results in a space limitation.
The outer diameter of a pad depends on the and the dimension of soldering balls or bumps and the dimension of solder mask openings. In other words, the outer diameter of a pad greatly depends on the pad structure and thereby determines the distance between two adjacent pads or the layout space of the trace lines, which however is not advantageous for the flexibility of layout design.
When the layout space of the trace lines is not enough, the layout space of the trace lines can be increased by reducing line width and line interval, but it would degrade the electrical performance, for example, causing signal reflection, crosstalk and coupling. Along with the tendency of high density of contacts, the above-mentioned problem becomes more and more serious.

Pad structure, circuit carrier and integrated circuit chip


A chopper amplifier circuit includes a first amplifier path with chopper circuitry, a switched-capacitor filter, and multiple gain stages. The chopper amplifier circuit also includes a second amplifier path with a feed-forward gain stage. A chopping frequency of the chopper circuitry is greater than a threshold frequency at which the second amplifier path is used instead of the first amplifier path.

Modern electronic systems involve different circuits and networks, where the voltage or current levels of signals conveyed along links between components or circuits are often adjusted. Signal amplifier circuits are one type of circuit that is used to adjust the voltage or current levels of signals along a link, where the goal of signal amplification is to increase signal strength without introducing errors like offset voltage, noise, distortion, etc. There are several different signal amplifier topologies, each suitable for different scenarios.
One signal amplifier topology is referred to as a chopper amplifier. In an example chopper amplifier topology, the chopping frequency is a function of the bandwidth (increasing the bandwidth necessitates an increase in the chopping frequency).
Unfortunately, increasing the chopping frequency of a chopper amplifier to increase the bandwidth results in an undesirable increase in the input bias current. The input bias current is directly proportional to chopping frequency as the chopping frequency determines the number of times a charge-transfer occurs per second on the inputs. This is because charge transfer from clock-feedthrough and charge-injection from the input chopper switches contribute to an increased input bias current in chopper amplifiers. To the extent the input bias current level interacts with an input source's impedance, an error voltage is introduced in the signal path.

Chopper amplifier with decoupled chopping frequency and threshold frequency


An example embodiment of the present invention provides a pole cap for covering an end of a pole. The pole cap comprises a sheet that includes a central portion, a first strip, and a flap that has a slit. The central portion is configured to cover a base surface of an end of a pole. The first strip is configured to fold over an edge of the base surface and circumferentially wrap around a portion of a curved surface of the pole. The flap is configured to fold over the edge of the base surface.

The tops of wooden poles can deteriorate due to fungus decay or exposure of the wooden pole to weather elements. A primary cause of this deterioration is the entry of moisture at end surfaces of the poles due to the exposed end grains. Water can collect in slight depressions of an end of the pole, which can be caused by decay, and the water can cause wood fibers to shrink and swell and/or freeze and thaw. Cracks may develop which can eventually allow moisture and decay to travel beyond any original treatment to the wood, breaking down additional wood fibers. If wooden poles are neglected, decay may become severe enough to necessitate replacement of the pole.
Previous attempts to protect pole tops from deterioration include cover caps, such as those composed of polyvinylchloride (PVC) material. Installation of these cover caps generally requires them to be nailed to the tops of poles, which may prove dangerous, as use of a hammer and nails may be required near live electrical wires. Additionally, these cover caps are generally provided in different sizes to fit different size poles, requiring a stock of different sized cover caps to be carried in the field in order to accommodate a variety of pole sizes.
Another attempt requires a protective fluid to be poured over the top end of a utility pole, after which a flowable asphalt-based material must be applied to the top of the utility pole. The asphalt-based material must then be allowed to cure. This method may be cumbersome, time consuming, and messy.
Another method that attempts to protect pole tops from deterioration includes the on-site manufacture of a synthetic resin cap that includes an end plate covering the end surface of the pole and a skirt that extends downwardly from the end plate and around the pole. A foamed resin may also be applied between the cap and the pole to prevent entrance of moisture. This method may be difficult and time consuming.
Another attempt requires application of a preformed cap that is made of elastic and water-impervious material to the top of a pole. To accomplish this, however, a frame must be used to position and apply an outwardly stretched cap to the top end of the pole. To attach the cap to the top of the pole, the frame must then release the cap, allowing the cap to contract to attach the cap to the top of the pole. Such caps may not adequately seal to prevent the entrance of moisture to the top end of the pole. Furthermore, there may be an increased danger of accidentally touching live electrical wires due to the difficulty and awkwardness presented by the application method of these caps.
Another method is a moisture barrier comprising a sheet of moisture-adverse material that can be adhered to the top end of a pole. In such a method, the sheet is configured to fold about the edge of the pole's end. Existing methods, however, may not be configured to provide a tight fit to the end of the pole, creating a discrepancy between the geometry of the end of the pole and the geometry of the moisture barrier. Such a discrepancy may increase the likelihood of a breach in the seal of the moisture barrier, thus allowing the entrance of moisture to the top end of the pole.
Therefore, there is a desire for a protective pole cap that may be installed easily, quickly, and safely. Further, there is a desire for a single-sized pole cap that will snugly fit a variety of sizes of poles. Various embodiments of the present invention address these desires.

This patent is subject to a terminal disclaimer.


A computer-generated hologram recording apparatus includes a diffraction image generator which receives an input image signal representing an object and computes a corresponding diffraction pattern with a first sampling density. An interpolation processor is connected to the diffraction image generator via an intermediate page memory. The interpolation processor subjects the diffraction pattern to the interpolation process to create an interpolated diffraction pattern with an increased second sampling density. An interference pattern generator is connected to the interpolation processor to compute an interference caused pattern between the interpolated diffraction pattern and a reference wave by converting amplitude and phase distributions of the input image signal into the intensity distribution. A multi-beam scan printing apparatus records the interference pattern on a previously selected recording medium for later reproduction by use of white light.

1. Field of the Invention
The present invention relates generally to holographic imaging techniques and, more particularly, to an apparatus for forming holographic images corresponding to input object image information for later reproduction or reconstruction of three-dimensional (3-D) optical images. This invention also relates to a computer-assisted hologram recording system for computing a wave disturbance (diffraction image pattern) obtained on the hologram recording surface based on a sampled data of a 3-D object of interest and for recording or printing on a recording medium the pattern of interference between the resultant diffraction pattern and reference light.
2. Description of the Related Art
Computer holography is generally known as a technique for forming a hologram by computing and recording the holographic image pattern of a 3-D object on a recording medium, such as a planar holographic plate or sheet, under the assistance of digital computer equipment. With the recent development of digital equipment, the computer hologram recording technique is becoming important more and more in the application field of 3-D image information processing, 3-D object measurement, 3-D display and so forth. Particularly, the technique of forming and reproducing holograms viewable in white light is important as stereoscopic image memory devices in the art of computer image processing.
Unlike the existing purely optical hologram devices, the computer-hologram apparatus produces by computation a holographic image pattern to record a resultant computer-generated holographic image on a recording medium of selected type. Since the computer can create any desired 3-D object images including imaginary graphic images, the computer hologram is excellent in flexibility and wide in applicability for industrial use. The presently available computer hologram apparatus, however, suffers from the fact that the efficiency of computation remains low. An increased amount of repetitive computations should be required to produce a computer hologram. The necessity of such repetitive computations forces the total processing time to increase, which necessitates the use of a large-scale computer system. This reduces the production efficiency of 3-D object hologram which is required to be recorded to maintain the high quality of a reproduced image.
Until today, several techniques have been proposed for reducing in amount the image information to be processed, thereby to attain an increased computation efficiency in the art of computer holography. One of the techniques may be found in what is called the "Lohmann type" computer hologram apparatus as is well known among those skilled in the art. This computer hologram apparatus generates a hologram by computing the diffraction pattern of an object. The computation algorithm is described, for example, in "Precision Machine", Vol. 47, No. 12, Supplement, (Dec. 6, 1981) at pp. 101-105, wherein a computer-generated hologram is formed by (1) inputting an object information to the computer, (2) deriving the wave of an object on the hologram plane by computation of the diffraction image to produce a binary-coded recording pattern, (3) creating an original picture drawing, and (4) reducing the original picture by photographing (completion of the hologram).
To reduce the amount of information to be computed, a hologram is created by dividing the hologram plane into a large number of small picture points (called "cells"), computing a diffraction pattern at the representative point of each cell to derive the complex amplitude and phase of each point, and giving an opening to each cell according to the computation results. The opening given to each cell is determined as follows: the height of opening is determined in accordance with the computed value of the complex amplitude of a corresponding cell, whereas the positional relation (distance) between the center of the opening and the cell center is determined in accordance with the value of the phase. The method of determining the size and position of the opening for each cell is described in detail in A. W. Lohmann & D. P. Paris "Binary Fraunhofer Holograms generated by Computer" Appl. Oct., Vol. 6, No. 10 (October 1967) at pp. 1739-1748. An original object image can be optically reconstructed or reproduced by applying a coherent reproducing light such as laser light to the recorded hologram. A resultant reproduced image obtained from the computer hologram, however, is not satisfactory in the image quality. This is because the center of the cell opening is positionally deviated from the representative point used as the basis for computations of phase.
Another method of creating a computer hologram is also known which is based on the computation of a fringe-shaped interference pattern. The interference computation type computer-generated holography is conceptually similar to a conventional optical hologram forming scheme in that a reference light emitted from a laser source is superposed on the diffraction image of an object of interest to derive an interference pattern therebetween. The recording of a hologram is performed so that the transmissivity or the density may vary on a photographic plate in accordance with the intensity of a resulting fringe-like interference pattern.
According to the interference computation type computer-generated holography, unlike the aforementioned diffraction computation type (i.e., Lohmann type) computer-generated holography, the phase information of a holographic image is recorded in the interference fringe form. The phase error can thus be minimized, which leads to enhancement of the image quality. However, the interference computation type holography suffers from the decreased computation efficiency due to the fact that the decisive means for reducing the amount of information used to compute the interference pattern has not been accomplished yet. Extra large-capacity semiconductor memories are necessary to execute the computation for an enormous amount of information. This results in that the scale of the hologram recording system is increased unwantedly, which makes almost impossible the accomplishment of a high-speed computation process with the use of a smaller computer system. This is a serious bar to the industrial spread of the computer hologram recording system.

Computer-assisted holographic image formation technique which determines interference pattern data used to form the holographic


The present invention discloses a method and system for certifying and verifying gemstones and a document certifying and verifying gemstones. The method comprises the steps of capturing at least one image of an inclusion in a gemstone; storing the image in a first database; and displaying the image on a certification document for presenting to a consumer, wherein the image is of sufficient magnification to allow the consumer to compare the image on the document to the gemstone viewed through an optical device to determine if the gemstone matches the image.

It is known to provide a certificate to identify and certify a gemstone. Such certificates are often provided at the time of sale by a jeweller, but can also be provided at other times by independent gemstone certification laboratories.
Examples of certification laboratories include:
GRS (Gem Research SwissLab)
SSEF (Swiss Foundation for Gemstone Research)
Gubelin (Gubelin Gem Lab)
GIA (Gemmological Institute of America)
NGI (Nan Yang Gemmological Institute)
IGI (International Gemmological Institute)
HRD (HRD Antwerp Institute of Gemmology)
EGL (European Gemmological Laboratories).
Conventionally, gem certificates identify the gemstone through a series of written description in respect of the cut, colour and shape of the gemstone, and its size or measurement. Although this is helpful, it is not entirely accurate, as the accuracy is dependent on the author of the description at the time the certificate is produced. Some certificates also provide a photograph of the gemstone being certified.
Many gemstones can appear to have the same cut, colour, shape and even size or measurement. Therefore, when a customer gives his/her gemstone to a jeweller for assessment or repair, cleaning, resetting or re-designing, there is a chance that it can be swapped for a lesser gemstone with the same outward appearance and clarity without the customer knowing.
Inside each gemstone there are internal features, known as 'inclusions', which are unique and individual to each gemstone. Inclusions are usually other minerals or rocks present in the gemstone, but may also be water, gas or petroleum. These inclusions are likened to the gemstone's personal DNA or fingerprint.
Coloured gemstone certification in some cases provide written descriptions of internal and external features in the gemstone, for example, under a heading of 'Observations'. Some certificates will also plot such features in the form of a diagram and this is included in the certificate issued. Often these descriptions and diagrams are too technical for a lay-person to understand, adding to the uncertainty of whether a particular gemstone has been swapped by a jeweller.
It is an object of the present invention to enhance the certification credibility and accuracy of gemstone verification.

Method and system for certification and verification of gemstones


The present disclosure relates to a weighing assembly (100) for a luggage case (101). The weighing assembly (100) includes at least one support (107) in contact with a surface that supports a portion of a weight of the luggage case (101). A floating element (108) is coupled to the support (107). A deflection member (110) is coupled to the floating element (108), and the portion of the weight of the luggage case (101) causes an elastic deflection of the deflection member (110). A load cell member (112) disposed adjacent to and separate from the deflection member (110). The load cell member (112) is separate from the deflection member (110) the elastic deflection of the deflection member (110) causes a deflection of the load cell member (112), the load cell member (112) senses the amount of deflection, which correlates to the portion of the weight of the luggage (101).

Travelers frequently pack personal belongings in luggage articles for transport during a trip. Many carriers, such as airlines, impose weight limits on luggage articles. Problems can arise when a traveler does not realize a luggage article is overweight until checking in at the airport, for example, when the luggage is placed on a scale. The traveler may not, at that time, be able to lighten the load in the luggage article, and further may not want to face the embarrassment of unpacking the luggage in a public setting, while holding up a queue.
Weigh systems have been developed for luggage articles that allow an article to be weighed using sensors associated with the luggage article. Many of these systems employ a fish-scale type of solution that weighs a luggage article when a user lifts the luggage off the ground. Such systems have the disadvantage of requiring a user to lift the luggage, which some users may not be able to do.
It is therefore desirable to provide an improved integrated weigh system for a luggage article that allows a user to determine a weight of the luggage without the luggage being lifted

Integrated weighing system for a luggage case


An overdrive unit for a vehicle is operatively connectable to a transverse mounted front wheel drive vehicle gearbox, which has been arranged to provide a single output shaft. The overdrive unit includes a planetary gear set and a differential are mounted together in an overdrive unit housing such that the output shaft of the vehicle gearbox is operatively connectable to the planetary gear set. The planetary gear set is further operatively connectable to drive shafts of the vehicle via the differential. A clutch unit is provided for selectively engaging gearing of the planetary gear set.

An overdrive unit is a device which has been commonly used in automotive vehicles to allow the choice of an extra-high overall gear ratio for high speed cruising, thus saving fuel, at the cost of less torque.
Early manual automotive transmissions were limited to three or sometimes four speeds, with only the more sophisticated having five speeds. This left an unfulfilled need for a higher gear ratio for highway cruising, which was filled by the addition of separate overdrive units (auxiliary or bolt-on), in order to simulate an extra gear.
It is today a desire to achieve even more fuel efficient automotive vehicles and even though manual automotive transmissions today sometimes will have more than 5 speeds, the engine speed will sometimes be too high for optimum CO2 driving at the highest gear.
However, with manual automotive transmissions (gearboxes) it is difficult to add more than 6 speeds, because of the increased effort it means for the driver to manually change gears more frequently. Furthermore, it will be difficult for the driver to decide when to change gears for optimum CO2 driving.
Also, the addition of more gears will normally increase the overall length of the transmission, while the addition of gears in a base transmission would normally require substantial redesign of the vehicle due to the increased space requirements.


Disclosed are devices and methods for creating a bore in bone. The devices and methods described involve driving a rotating bit in an axial direction such that both rotation and linear movement are controlled and measurable. The instrument is useful for a surgeon to control and simultaneously measure the travel of the tool into the bone and prevent injury to surrounding structures.

Orthopedic surgery can require bone drilling for the repair of fractures or insertion of implants or other devices. The resulting holes are needed to accept screws, implants and other devices to exert pressure, fixation or reduction of the bone. During any procedure where a drill or other driver is used to advance a tool into and through bone, the operator must consciously and carefully limit the penetration to the desired depth. If the operator allows the tool to penetrate further, the patient can suffer injury to distal structures such as nerve, brain, spinal cord, artery, vein, muscle, fascia, bone or joint space structures. These types of injuries can lead to severe patient morbidity and even death. The devices inserted to a drilled bore often must fit within a narrow length range that can vary sometimes by no more than a millimeter or less.
Once the drilling of a bone is safely complete, it is often prudent to obtain the depth of the bore made by the drilling tool. Many procedures require knowledge of the depth of tool penetration, such as in the placement of internal fixation devices, screws and other implantable hardware. Selecting an appropriate length of the screw or other implant necessary for the procedure depends upon such knowledge of the bore's depth. Conventional techniques used in the art are often inconvenient, time consuming and unreliable often requiring trial and error and multiple exposures to radiographs before the proper implant insertion is achieved.
A common way to obtain the depth of the bore formed by a drilling tool is to use a depth gauge. Often surgeons must interrupt the drilling procedure in order to palpate or measure with a depth gauge whether or not the desired depth has been achieved. In many instances a surgeon will take a radiograph during a drilling procedure to confirm the appropriate depth of penetration has been achieved or take a radiograph while the depth gauge is in place to ensure the information the gauge provides is accurate. Depth gauges used in the art can be inaccurate resulting in a surgeon placing a screw of an inappropriate length not often identified until a confirming radiograph is taken. Each radiograph taken increases the radiation exposure of the surgeon, staff and patient in the operating suite. Depth gauges known in the art can also break and require the surgeon to retrieve it from the bore. Inconvenient and inaccurate depth measurement devices and methods known in the art can result in improperly sized screws that must be removed and replaced with new properly sized screws. Wasted hardware, increased disruptions and delays in orthopedic procedures ultimately increase the expense of a procedure as well as exposing the surgeon, staff and the patient to unnecessary radiation. The cost of the additional time, the wasted hardware and the radiation exposure are quite significant.

Depth controllable and measurable medical driver devices and methods of use


The present invention provides a method for removing charged defects from a material stack including a high k gate dielectric and a metal contact such that the final gate stack, which is useful in forming a pFET device, has a threshold voltage substantially within the silicon band gap and good carrier mobility. Specifically, the present invention provides a re-oxidation procedure that will restore the high k dielectric of a pFET device to its initial, low-defect state. It was unexpectedly determined that by exposing a material stack including a high k gate dielectric and a metal to dilute oxygen at low temperatures will substantially eliminate oxygen vacancies, resorting the device threshold to its proper value. Furthermore, it was determined that if dilute oxygen is used, it is possible to avoid undue oxidation of the underlying semiconductor substrate which would have a deleterious effect on the capacitance of the final metal-containing gate stack. The present invention also provides a semiconductor structure that includes at least one gate stack that has a threshold voltage within a control range and has good carrier mobility.

As is known to those skilled in the semiconductor art, transistors are the main building blocks of integrated circuits (ICs). Modem ICs interconnect millions of densely configured transistors that perform a wide variety of functions. To achieve this densely packed configuration, the physical dimensions of the transistors are typically scaled down to the sub-micron regime. Generally, the transistors used in the sub-micron regime typically include a polysilicon gate. However, polysilicon gates may suffer device performance degradation due to a polysilicon depletion effect in which an electric field applied to a polysilicon gate removes carriers (holes in a p-type doped polysilicon, or electrons in an n-type doped polysilicon) so as to create a depletion of carriers in the area of the polysilicon gate near the underlying gate dielectric of the transistor. This depletion effect results in a reduction in the strength of the electric field at the surface of the CMOS device when a voltage is applied to the polysilicon gate electrode, which can have an adverse affect on the transistor performance.
One proposed way of improving the performance of sub-micron transistors is to use metal gates in place of conventional polysilicon gates. While replacing traditional polysilicon gates with metal or metal alloy gate electrodes eliminates the polysilicon depletion effect, there are still problems associated with the use of such metal gates. Another way of improving the performance of a CMOS device is to include a conductive oxide as a contact layer. In such instances, the conductive oxide controls the threshold voltage of the CMOS device rather than the conductive metal used as the metal gate.
One problem encountered with metal gates is that the carriers from the metal gate can diffuse into the underlying gate dielectric material, thus causing shorting of the device.
In addition to using metal gates as a replacement for polysilicon gates, there is much research ongoing that deals with replacing conventional dielectrics such as silicon dioxide or silicon oxynitride with a gate dielectric that has a high dielectric constant. These materials are known in the art as "high k" materials with the term "high k" denoting an insulating material whose dielectric constant is greater than 4.0, preferably greater than 7.0.
CMOS technology can gain scaling advantages through the use of high k gate dielectrics with metal gates. These new components would replace the conventional polySi/SiO2 technology that is used today. However, difficulties have risen in implementing metal gate/high k technology, principally involving the threshold voltage (Vt) of the devices. This problem is particularly relevant in pFET devices.
CMOS processing inevitably requires high temperature (on the order of greater than 550° C.) steps to activate source/drain dopants, as well as reducing steps to passivate interfaces. It is commonly observed that after this processing, positive charge is induced in the dielectric that alters the threshold voltage of the device. The change in threshold voltage for a typical device gated with a p-type metal (with a workfunction near 5 eV) is 300-700 mV. In other words, the effective workfunction of the metal has moved from the silicon valence band to the middle of the silicon band gap. This would render a CMOS circuit including such a pFET device inoperable. During the high temperature processing, oxygen deficiencies have been created in the metal oxide. Schaeffer et al. "Contributions of the effective work function of platinum on hafnium dioxide", Applied Physics Letters, Vol. 85, No. 10, Sep. 6, 2004, pp.1826 discuss these as interfacial vacancies. The interfacial vacancies can also be referred to as charged defects. It is also possible that these charged defects are conventional bulk oxygen vacancies in the high k gate dielectric that are electrostatically attracted to the interface formed between the gate conductor and the gate dielectric.
In view of the above, there is a need for providing a method of fabricating CMOS structures including a gate stack comprising at least a high k gate dielectric from which the charged defects have been substantially removed from the gate stack.

Removal of charged defects from metal oxide-gate stacks

International Business Machines Corporation


A push button switch used for a personal computer or a word processor, which uses a membrane switch in a contact portion. The push button switch comprises a casing, a key top slidably guided along the casing, a contact portion arranged below the key top, an actuator rotatably supported on the casing to open and close the contact portion, a spring retained in a curved orientation between the actuator and the top key, and a click portion provided on the actuator by which a curved side of the spring is pressed, the clock portion of the actuator actuated by downward movement of the key top urging the side of the spring so as to invert the curved orientation of the spring.

1. Field of the Invention
The present invention relates to a push button switch used for a personal computer, a word processor and the like, and more particularly to a push button switch which uses a membrane switch in a contact portion and has a click feeling.
2. Description of the Prior Art
A prior art push button switch of this kind is as shown in FIGS. 6 (a) and (b), which are respectively sectional views showing the state before and after the depression of a key top of a conventional push button switch.
In these Figures, a key indicated at 1 is mounted slidably along a hollow cylindrical supporting body 3 which is stood upright on a frame 2. The frame 2 has one cylindrical supporting body 3 per to one key 1 on a keyboard. The frame 2 is mounted on a base plate 4.
The key 1 has a downwardly extending mandrel 5. The mandrel 5 is located on the inside of the cylindrical supporting body 3 of the frame 2, whereby the key 1 is within the cylindrical supporting body 3, and whereby the the key 1 is slidably moved within the cylindrical supporting body 3. In the outer surface of the mandrel 5 having two bifurcated and separated skirt portions 6 (only one of which is shown) and in the inner surface of the cylindrical supporting body 3, a rib and a slot are provided so that during the movement of the key 1 in a vertical direction, the rib and slot cooperate to direct and guide the movement of the key 1.
A spring 7 is compressed between the key 1 and the actuator 8. When the key 1 is depressed, the actuator 8 of a pivotal type closes a contact switch 10 of a membrane contact switch construction 9. An upper end of the spring 7 acts on a mounting bed 11 which is present in the mandrel 5 of the key 1. The mounting bed 11 is slightly inclined so that the spring 7 is bent in a first selected direction (rightward in FIG. 6 (a)) when the key is not pressed. Buckling of the spring 7 in a lateral direction is restricted by the skirt portion 6 of the mandrel 5.
Since the actuator 8 is always at rest on the upper surface 12 of the membrane contact switch construction 9, the spring 7 always provides an upward bias the key 1. The upward movement of the key 1 is restricted by stop portions 13 (only one of which is shown). The stop portions 13 are adjacent to each skirt portion 6 of the mandrel 5 are affixed to the outer surface of the skirt portions 6, and are in engagement with shoulders 14 (only one of which is shown) on the inner surface of the cylindrical supporting body 3. Each of the stop portions 13 has an inclined surface. The inclined surface of the stop portion 13 is paired with the inclined surface of the shoulder 14 so that in the case where in assembling the keyboard or in replacing the key 1, the key 1 can be inserted into the cylindrical supporting body 3 and each stop portion 13 will be obstructed by the shoulder 14.
In the state wherein the key 1 is not depressed and is pushed up to the uppermost end by the spring 7, the actuator 8 is at rest as shown in FIG. 6 (a). In this state, surfaces in contact with the upper surface of the membrane contact switch construction 9 are only a bottom surface 16 of a supporting bed 15 of the actuator 8 and a bottom surface 18 of a supporting bed 17. The bottom surface 16 of the supporting bed 15 and the bottom surface 18 of the supporting bed 17 are sufficiently distant from a contact switch 10, when the actuator 8 is at rest. Thus, even though the spring 7 is compressed, no force is applied to the contact switch 19. When the actuator 8 is at rest, there is a slight clearance between a bottom surface 21 of a projection 20 and the upper surface 12 of the membrane contact switch construction 9.
The membrane contact switch construction 9 has an upper layer 22, an intermediate layer 23 and a lower layer 24. The upper layer 22 has a bottom surface 25 formed with circular contacts 26 (only one of which is shown). The lower layer 24 has an upper surface 27 formed with a circular contact 28 (only one of which is shown). The intermediate layer 23 is formed with a circular opening 29. These circular contacts 26 and 28 constitute a contact switch 10. Accordingly, when the upper layer 22 is moved into the circular opening 29 of the intermediate layer 23, the circular contact 26 and the circular contact 28 contact to close the contact switch 19, as shown in FIG. 6 (b).
When the key 1 is depressed from the FIG. 6 (a) position to the FIG. 6 (b) position, force F transmitted by the spring 7 to the actuator 8 is increased by the force applied to the key 1. When the force F becomes greater than the force when the actuator 8 is at rest, moment M becomes larger than a moment formed by a product of the force F and a distance x. The moment M is produced when the spring 7 is excessively buckled from the FIG. 6 (a) position to the FIG. 6 (b) position to increase the buckling amount thereof. The actuator 8 is rotated about an initial pivot, that is, about fore ends 30 and 31 of the bottom surface of the supporting bed. By this clockwise rotation, the bottom surface 21 of the projection 20 comes into contact with the upper surface 12 of the membrane contact switch construction 9. This forces the upper layer 22 of the membrane contact switch construction 9 to move into the circular opening 29 of the intermediate layer 23. Accordingly, the circular contact 26 of the bottom 25 of the upper layer 22 comes into contact with the circular contact 28 of the upper surface of the lower layer 24.
When the actuator 8 is rotated about the initial pivot, the bottom surface 21 of the projection 20 of the actuator 8 comes into contact with a point 32 of the upper layer 22 of the membrane contact switch construction 9.
When the contact switch 10 is closed, an user feels this by the excessive buckling (FIG. 6 (b)) of the spring 7, and thus releases his finger from the key 1.
In the aforementioned prior art, the spring 7 provided between the key 1 and the actuator 8 is buckled by the downward movement of the key 1 to obtain a click feeling. Since the buckling of the spring 7 is due solely to longitudinal forces on the ends of the spring, the timing of the buckling can vary as properties of the spring vary within manufacturing tolerances. This variation in timing can result in unstable switching and unstable tactile feedback for an operator. Further, there is a limit as to how short the spring can be for a given set of parameters if buckling is to be produced by longitudinal forces applied to the spring. This problem limits the compactness of the switch.

Push button switch with actuator for applying transverse force to buckling spring