A device for measuring the temperature of an external moving filament is disclosed. The device includes dual thermal sinks or reference bodies; each reference body has two heat flow sensors that are matched in sensitivity and are connected in series. By utilizing dual thermal reference bodies, which are maintained at different temperatures, the device yields the absolute temperature of the filament by measuring the temperatures of the referenced bodies and the heat flow rates between each of the reference bodies and the filament. The device automatically calculates the proportionality constant between the heat flow rates and the temperature differences between the filament and the reference bodies and thus calculates the filament temperature. Each heat flow sensor has a row of sensitive elements or active junction lines that is not parallel to the path of the filament. This orientation of the sensitive elements provides more accurate temperature measurements even when the path of the filament should constantly change.

This invention relates generally to a method and apparatus for measuring the temperature of an external medium or approximate body, and particularly a moving external body.
The temperature of moving and non-moving objects is generally now measured by a variety of methods and apparatuses including non-contact temperature detection devices which rely on the principle that net heat exchange between a reference body and an external body is zero when the bodies are at the same temperature. Reference is made to U.S. Pat. Nos. 3,542,123 and 3,715,923 for details regarding an apparatus employing this principle. Such non-contact devices contain a high thermal conductivity reference body mounting a heat flow sensor to determine the heat flow between the reference body and an external body located adjacent to the reference body. A temperature sensor provides a signal proportional to the temperature of the referenced body. In addition, the apparatus includes means for establishing the spacing between the reference and external bodies so that the heat flow sensor output signal can be calibrated to yield the absolute temperature of the external body.
As the external body moves past the heat flow sensitive surface of the reference body, heat will be exchanged by convection between the external and reference bodies whenever they are not at the same temperature. This will cause heat to flow into or out of the sensing head surface of the reference body. The magnitude of heat flow will be proportional to the temperature difference between the bodies, the distance between the bodies, and the thermal conductance of the heat flow path across the spacing between them. By keeping the spacing constant, it is possible to calibrate the heat flow rate, measured by the heat flow sensor in the reference body, as a function of the temperature difference between the reference and external bodies for a given reference body temperature. By adding this measured, calibrated temperature difference between the bodies to the reference body temperature measured by the temperature sensor in the reference body, the temperature of the external moving body is obtained. While the devices are primarily used to measure the temperature of moving objects, they are suitable for many applications involving stationary objects as well.
However, one major drawback of these non-contact devices is that they must be manually recalibrated whenever the spacing or heat transfer conditions between the reference and external bodies changes, thereby resulting in unnecessary delays.
Therefore, it is a primary object of the present invention to provide an improved, convenient method and apparatus for measuring the temperature of an external body that continues to function even as conditions between the apparatus and external body change.
It is another object of the present invention to provide an improved method and apparatus for measuring the temperature of an external body that automatically calculates the proportionality constant between the heat flow rate and the temperature gradient between the external body and the reference body.
It is a further object of the present invention to provide an improved method and apparatus for measuring the temperature of fast-moving continuous elements such as wires, filaments, webs and rolls.

Autocalibrating dual sensor non-contact temperature measuring device


A control circuit for a power supply having a controllable switch for switching a current through a first transformer winding and a voltage providing circuit for providing an output voltage based on a voltage generated in a second transformer winding has a comparing unit for generating a comparison signal. The control circuit has a threshold signal modulation circuit adapted to modulate the threshold signal that the comparison signal is activated as soon as the input signal crosses a first threshold value, if the current flowing through the switch exhibits a first current slope rate, and that the comparison signal is activated as soon as the input signal crosses a second threshold value, if the current flowing through the switch exhibits a second current slope rate smaller than the first rate. For a given voltage, the first threshold is smaller than the second threshold.

In present applications a large number of requirements is set up for switching power supplies. For example, a power supply needs to be capable of providing a large output power. Furthermore, it is required that a switching power supply comprises a low standby power consumption in case a load current provided to a circuit supplied by the power supply is comparatively small.
It was found that a low standby power can be achieved by using an active burst mode, which will be described in more detail in the following.
FIG. 7 shows an example of a switching power supply offering an active burst mode. The circuit of FIG. 7 is designated in its entirety with 700. The circuit 700 receives an alternating voltage at an input 710 and provides a converter DC output voltage at an output 712. A rectifying circuit 714 generates a DC voltage 716 which is buffered by a buffer capacitor 718. Further, a first winding 720 is connected in series with a drain-source-path of a MOS-field effect transistor 722 and a current sense resistor 724 between the DC voltage 716 and a reference potential GND, wherein the voltage over the current sense resistor 724 is a pulse voltage which is present at 772. Besides, a snubber 726 is connected in parallel with the first winding 720. A gate terminal of the MOS-field effect transistor 722 is controlled by an integrated circuit 730, which will be described in more detail in the following.
The first winding 720 is part of a transformer 740 that further comprises a second winding 742 and a third, auxiliary winding 744. The second winding 742 is connected, via a rectifying diode 746, to a filter network 748. The filter network 748 comprises two capacitors and an inductor in a H circuit configuration. An output voltage VOUT is available at the output port of the filter network 748.
The circuit 700 further comprises a feedback circuit 750. The feedback circuit 750 comprises an optocoupler 752. A current flowing through a light emitting diode of the optocoupler 752 is dependent on a voltage at an input port of the filter network 748. The current through the light emitting diode of the optocoupler 752 is further dependent on a voltage present at the output 712 of the circuit 700. Thus, the current through the light emitting diode of the optocoupler 752 increases with an increasing voltage at the input of the filter network 748. An npn-photo-transistor of the optocoupler 752 is connected between the ground potential GND and a feedback input FB of the integrated circuit 730.
It should be noted here that a collector terminal of the photo transistor of the optocoupler 752 is pulled to a voltage which is positive with respect to the reference potential GND over a resistor RFB within the integrated circuit 730. Thus, a feedback voltage at the feedback input terminal FB of the integrated circuit 730 decreases with an increasing photo current. In other words, if the voltage at the input port of the filter network 748 increases, the voltage at the feedback terminal FB of the integrated circuit 730 decreases and vice versa.
In the following section, details of the integrated circuit 730 will be described. However, for a full description of the operation of the circuit 700 reference should be taken for example to the datasheet titled "F3; ICE3AS02/ICE3BS02, ICE3AS02G/ICE3BS02G, Off-Line SMPS Current Mode Controller with Integrated 500V Startup Cell, Version 1.2", dated Sep. 2, 2005, which is available from Infineon Technologies AG.
The integrated circuit 700 comprises a total of seven terminals. A soft start terminal 760 is connected over a capacitor 762 with the reference potential GND. The soft start pin combines the function of a soft start during a startup of the integrated circuit 730 and an error detection for an auto restart mode. These functions are implemented and can be adjusted by means of the external capacitor 762 connected between the soft start pin 760 (also designated with SoftS). The capacitor also provides an adjustable blanking window for high load jumps before the integrated capacitor 730 enters into the auto restart mode, which will be described below.
A feedback pin 764 (also designated with FB) receives an information about the regulation. The information received over the feedback pin 764 is provided to an internal protection unit and to an external pulse width modulation comparator to control the duty cycle of the MOS-field effect transistor 722. The signal at the feedback pin 764 further controls the active burst mode of the integrated circuit 730 in case of a light load at the output 712.
A high voltage pin 765 (also designated with HV) is connected to the rectified DC input voltage 716. The rectified DC voltage 716 is the input for a startup cell integrated in the integrated circuit 730.
A power supply pin 766 (also designated with VCC) is the positive supply of the integrated circuit 730. The voltage at the power supply pin 766 is derived from the third winding 744 of the transformer 740 over a one-way rectification circuit.
The integrated circuit 730 provides a drive signal to an external MOS-field effect transistor 722 over a gate pin 768.
Besides, the integrated circuit 730 senses the voltage developed over the current sensing resistor 724 (the series resistor inserted in series with the drain-source-path of the MOS-field effect transistor 722 and the first winding 720 of transformer 740). A voltage proportional to the current through the current sensing resistor 724 (and the first winding 720, unless some current is flowing through the snubber circuit 726) is fed into a current limiting circuit 770 via a current sense pin 772 (also designated with CS). If the voltage at the current sense pin 772 reaches an internal threshold of a current limit comparator CIO included in the current limiting circuit 770, the MOS-field effect transistor 722 is immediately switched off. Furthermore, the current information input into the integrated circuit over the current sense pin 772 is provided (in a scaled form) to a pulse width mode comparator C8 to realize a regulation.
The integrated circuit 730 consists of a number of blocks, which will be described in more detail in the following. A control unit 800 controls different states of the integrated circuit 730. Transitions between the operating modes, for example a soft start mode, an active burst mode, a current mode, and additional protection modes, are initiated depending on a voltage at the soft start pin 760 and a voltage at the feedback pin 764.
For the understanding of the present invention, the current mode, which constitutes a normal operation mode of the switching power supply 700, and the active burst mode, which constitutes an energy saving operation mode of the switching power supply 700, are particularly relevant. Therefore, these modes will be described in detail in the following.
The integrated circuit 730 provides the active burst mode for low load conditions at the output 712. During the active burst mode, which is controlled only by the voltage at the feedback pin 764, the integrated circuit 730 is active and can therefore immediately respond to fast changes at the feedback pin 764. At the same time, a comparatively low (lower than in the normal mode) power consumption of the switching power supply is ensured.
If the voltage at the feedback pin 764, which is low pass filtered by a low pass filter network 802, falls below a level of 1.32 volt, a comparator C5 provides a signal to the AND-gate G6. If the respective condition (voltage at feedback pin 764 smaller than 1.32 volt) is maintained for a certain period of time, a delay circuit (consisting of the OR-gate G2, switch S1, a 4.4 volt zener-diode, a 5 kΩ resistor, capacitor 762 and comparator C3) indicates that the active burst mode should be entered. The respective signal to enter the active burst mode is output by AND-gate G6. In other words, a time window is generated by combining the signal at the feedback pin 764 and the voltage at the soft start pin 760 with the AND-gate G6, which prevents a sudden entering of the active burst mode due to a large load jump. The time window is adjusted by the external capacitor 762. After entering active burst mode, a burst flag is set. An active burst mode control circuit 804 acts to limit the current flowing through the first winding 720 when the integrated circuit 730 is in the active burst mode. For this purpose, a current limit is set using the comparator C12 and the AND-gate G10, as will be described in more detail below.
Due to the current limit imposed in the active burst mode, conduction losses are reduced and a generation of audible noise by the switching power supply 700 is avoided. The operation of the active burst mode is further controlled by the voltage at the feedback pin 764, wherein the outputs of comparators C6a and C6b are used to decide whether to activate or deactivate the generation of current pulses in the first winding 720.
Upon entering the active burst mode, an internal bias of the integrated circuit 730 is switched off in order to reduce the current consumption of the integrated circuit 730. Under this condition, the MOS-field effect transistor 722 is not activated. After entering the active burst mode, the voltage at the feedback pin 764 rises, as a voltage at the output 712 of the filter network 748 begins to fall in the absence of current pulses in the first winding 720. Comparator C6a observes the voltage at the feedback pin 764.
If the voltage at the feedback pin 764 exceeds for example a level of 4V, the internal bias of the integrated circuit 730 is again activated. Thus, the integrated circuit 730 drives the MOS-field effect transistor 722 to generate current pulses, wherein the current flowing through the first winding 720 of the transformer 740 is limited to a comparatively small value, as determined by comparator C12. Due to the reactivation of the generation of current pulses in the first winding 720, the voltage in the filter network 740 increases again. Consequently, the voltage at the feedback pin 740 decreases.
If the voltage at the feedback pin 764 reaches for example a level of 3.4 volt, comparator C6b provides a signal to deactivate again an internal bias of the integrated circuit 730. As a consequence, a generation of current pulses in the first winding 720 is interrupted, until the voltage at the feedback pin 734 again reaches the above described threshold of e.g. 4.0V.
Consequently, the above-described sequence is repeated, deactivating the internal bias of the integrated circuit 730. The integrated circuit 730 remains in the active burst mode, until the load at the output 712 of the switching power circuit 700 is changed (increased). If a sufficiently high load connected to the output 712 of the switching power supply 700 is activated, the voltage at the feedback pin 764 increases. Such an increase is detected by the comparator C4. Thus, if C4 detects that the voltage at the feedback pin 764 exceeds a threshold value of for example 4.8 volt, the active burst mode is left. The output of comparator C12 is blocked upon a leaving the active burst mode, so that the current limitation imposed by the comparator C12 is no longer effective. So, after leaving the active burst mode, a maximum current can be provided (within the limits of the current limitation introduced by the comparator C10) to stabilize the voltage VOUT present at the output 712 of the switching power supply 700.
To summarize the above, the voltage at the feedback pin 764 is used to control the operation of an energy saving mode designated as active burst mode. When the voltage of the feedback pin 764 falls below a certain first threshold (e.g. 1.32 V) indicating a small load condition at the output 712 of the switching power supply, the active burst mode is entered, which results in a deactivation of the current pulses in the first winding 720 of the transformer 740. Only when the voltage at the feedback pin 764 exceeds a second threshold level (e.g. 4.0 volt), current pulses in the first winding are re-activated. As long as the integrated circuit 730 is in the active burst mode, a current limitation is imposed on the current pulses in the first winding 720, which is lower than a maximum current which is allowable when the active burst mode is inactive. If the integrated circuit 730 is in the active burst mode and current pulses are enabled, current pulses are generated in the first winding 720 until the voltage at the feedback pin 734 reaches another third threshold value (e.g. 3.4 volt). As soon as the feedback voltage reaches the third threshold value, the generation of current pulses in the first winding 720 is deactivated. Consequently, the voltage at the feedback pin 764 reaches the second threshold value (e.g. 4.0 volt) again, and the cycle is repeated. Thus, a hysteresis is achieved, as the generation of current pulses in the first winding is activated when the voltage at the feedback pin 764 reaches the second threshold value, and is deactivated when the voltage at the feedback pin reaches the third threshold value. Besides, the active burst mode is left when the voltage at the feedback pin 764 reaches a fourth threshold level (e.g. 4.8 volt).
It should be noted here, that the threshold levels described above will be referred to in the following as active burst mode threshold values.
In the following, the generation of a drive signal 810 for the MOS field effect transistor 722 will be described in detail. The drive signal 810 is generated in a pulse width modulation section 820. The pulse width modulation section 820 comprises an oscillator 822. The oscillator 822 generates two clock signals 824, 826 having the same frequency but different duty cycles. However, for the switching power supply 700 the rising edges of the first clock signal 824 and the second clock signal 826 coincide. The second clock signal 826 produces a short pulse to set a flip flop FF1. Provided the first clock signal 824 is active and a gate G8 does not provide an inhibiting signal, the setting of the flip flop FF1 results in a switching-on of the MOS-field effect transistor 722. On the other hand, as soon as the first clock signal 824 gets inactive or any of the inputs of gate G8 is activated, the MOS-field effect transistor 722 is switched off to interrupt the current through the first winding 720 of the transformer 740.
In other words, the MOS-field effect transistor 722 is activated upon a rising edge of the clock signals 824, 826 and is deactivate if either the first clock signal 824 gets inactive or any of the inputs of the gate G8 are activated. In the switching power supply 700 of FIG. 7 there are, apart from the deactivation of the first clock signal 824, four mechanisms that result in a deactivation of the MOS-field effect transistor 722.
All these mechanisms are based on a determination of the current flowing through the first winding 720 or the drain-source-path of the MOS-field effect transistor 720, respectively. The described current is sensed by the current sensing resistor 724, and a voltage proportional to the current flowing through the drain-source-path of the MOS-field effect transistor 722 is therefore provided at the current sense pin 772 of the integrated circuit 730. An input filtering is applied to the voltage at the current sense 772 of the integrated circuit 730 by a filter and input protection circuit 828. Further, a leading edge of the voltage at the current sense pin 772 is suppressed in a leading edge blanking circuit 830. A current describing signal 832, which is derived from the voltage at the current sense pin 772 and describes the current through the drain-source-path of the MOS-field effect transistor 722 (with the exception of leading edges, which are suppressed in the leading edge blanking circuit 830) is fed as an input signal into comparators C10 and C12. Comparator C10 compares the signal 832 with a threshold signal describing a maximum allowable current. If the current describing signal 832 exceeds the threshold signal applied to comparator C10, the comparator C10 sends an active signal to gate G8, which results in a deactivation of the MOS-field effect transistor 722. In other words, as soon as the current through the drain-source-path of the MOS-field effect transistor 722 exceeds a predetermined level, the MOS-field effect transistor 722 is switched off, so that a further increase of the current is avoided. So, comparator C10 provides a current limitation in the normal operation mode (non-energy saving operation mode).
Besides, when the integrated circuit 730 is in the active burst mode, the output of comparator C12, which compares the signal 830 to a predetermined current threshold signal (smaller than the current threshold signal provided to comparator C10), is coupled to the input of gate G8 over the AND-gate G10. In other words, in the active burst mode the MOS-field effect transistor 722 is deactivated as soon as the current describing signal 832 exceeds the value of the current reference signal applied to comparator C12.
The current describing signal 832 is further scaled to provide a scaled current describing signal 834 derived from the current flowing through the drain-source-path of the MOS-field effect transistor 722. The scaled signal 834 is compared with a low pass filtered feedback signal 840 derived from the signal present at the feedback pin 764 of the integrated circuit 730 in a pulse width modulation comparator C8. If the scaled signal crosses a threshold level defined by the (low pass filtered) feedback signal 840, the output of the pulse width modulation comparator C8, which is coupled to an input of the gate G8, is activated. Thus, in response to an activation of the output of the pulse width modulation comparator C8, the MOS-field effect transistor 722 is switched off.
Furthermore, during the startup of the integrated circuit 730, a signal provided by a soft start circuit 850 is effective to the switch of the MOS-field effect transistor 722.
In the following, in order to facilitate the understanding of the circuit 700, the (normal, current mode) operation of the circuit 700 will be described, based on the assumption that the integrated circuit 730 is neither in a soft start condition nor in an active burst mode condition, and that further the current limiting comparator C10 is inactive.
In this case, a duty cycle of the drive signal 810 for the MOS-field effect transistor 722 is determined by a regulation loop, wherein the voltage at the feedback pin 764 is derived from the voltage present in an output circuit of the switching power supply (the output circuit consisting of the second winding 742, the rectifying diode 746 and the filter network 748). The feedback signal 840 serves a reference signal for the pulse width modulation comparator C8. As soon as the scaled signal 834 descriptive of the current flowing through the MOS-field effect transistor 722 crosses a level defined by the feedback signal 840, the output of the comparator C8 is activated. In the response to the activation of the output of the pulse width modulation comparator C8, the MOS-field effect transistor 722 is deactivated after a delay time. If the voltage in the output circuit 742, 746, 748 of the switching power supply 700 is comparatively high, the feedback signal 840 has a comparatively low value. Thus, the output of the pulse width modulation comparator C8 is activated at a comparatively small value of the current flowing through the MOS-field effect transistor 722. Consequently, the duty cycle of the current flowing through the first winding 720 of the transformer 740 is comparatively low, which results in a reduction of the voltage in the output circuit of the switching power supply 700. In contrast, if the voltage in the output circuit 742, 746, 748 of the switching power supply 700 is comparatively low, the feedback signal 840 is comparatively high, which results in a comparatively high duty cycle of the current flowing through the first winding 720 of the transformer 740. This results in an increase of the voltage present in the output circuit of the switching power supply 700.
However, it was found that for example for a small load present at the output 712 of the switching power supply 700, the voltage of the feedback signal 840 (in an equilibrium state) varies significantly with changes of the DC voltage 716, which brings along significant problems when controlling activation and/or deactivation of power saving modes (like the active burst mode) on the basis of the feedback signal 840.

Control circuit for a switching power supply, method for controlling a switching power supply and computer program


A method of in-line surface-hardening of products is provided. In the process, the products are introduced into a chamber with at least one conveyor. The chamber includes a frigorie transfer means for surface-hardening the products. A surface hardened product is extracted from the chamber upon receipt of a product request signal emitted by a preparation unit located downstream of the device. The at least one conveyor is controlled to, upon receiving the product request signal, extract from the chamber the surface-hardened product which has resided longest in the chamber and, substantially at the same time, introducing into the chamber a new product to be surface hardened. The frigorie transfer means is controlled so as to control the quantity of frigories to be transferred to the products present in the chamber per unit time as a function of at least one elapsed period between two successive times at which preceding request signals from the preparation unit were received.

(i) Field of the Invention
The present invention relates to a device for in-line surface-hardening of products, intended to feed a unit for preparation of the products, this being downstream of the device, of the type comprising a chamber provided with frigorie transfer means for surface hardening the products and at least one conveyor for introducing the products into the chamber and for extracting them.
(ii) Description of the Related Art
Surface hardening a product is an operation consisting in freezing the surface of at least one of the faces of the product for the purpose of facilitating its subsequent preparation. This technique is used in particular to facilitate the slicing of bars of ham and of pork loins, but is also applicable to other food products which have to undergo cutting, salami, dry sausage, sausages, cheese, fish.
Currently known surface-hardening machines are formed by tunnels, open at one end for introducing the products and at one end for extracting the products, and through which extends a continuously running conveyor for transporting the products. Placed into the tunnel are frigorie transfer means formed, in particular, by means for spraying a cryogenic fluid, for example liquid nitrogen.
The current tunnels operate continuously so that the products enter and leave the tunnel at a constant rate. If an incident occurs at a slicing unit located downstream of the tunnel, requiring the latter to be stopped for a prolonged period, the conveyor in the tunnel is stopped by an operator such that the products remain for a prolonged period inside the tunnel. They are thus cooled for an excessive period such that they are frozen too much, in particular frozen to the core.
Upon restarting the installation, there is a risk of the excessively frozen products leaving the tunnel damaging the cutting blades of the slicing unit.
Similar problems are encountered if the slicing unit is made to operate at a slower rate, for example because of a different setting for the thickness of the slices produced. It is then necessary manually to switch to a new setting of the conveyor's speed of advance, and/or to define a new set point for the frigorie transfer means.
It will be appreciated that a "frigorie" is a negative calorie. The term is used when cold is transferred to an article such as during a food freezing operation by spraying a liquid cryogen on an article.

Device for in-line surface-hardening of products

L'Air Liquide, Societe Anonyme pour l'Etude et l'Exploitation des Procedes Georges Claude


A plurality of visualization objects may be provided for representing one or more data sets in a virtual 3D space. The visualization objects may include funnels, containers, name cards, and so forth. The visualization objects can be arranged in a circular carousel that can be rotated around a position of a virtual camera or user in a VR/AR environment. Individual data points in the visualization objects can be rotated, sized, positioned, colored, or otherwise characterized based on attributes of the corresponding data points. Individual data points can also be animated as transitioning between visualization objects in a unified view. Voice commands can be interpreted as part of an interactive environment that can provide views of the visualization objects to multiple devices simultaneously.

One of the most effective ways to convey formation is through visualization. Capturing and categorizing information is typically not sufficient to gain a full understanding of conclusions that may be drawn from the data. Although two-dimensional data visualizations dominate much of our communication technology, many of these visualization techniques are not optimized for highlighting or emphasizing aspects of the data collection. Effective data visualization involves creating informative visuals that communicate an aspect of the data very quickly. At times, simple visualizations are sufficient. However, with complex multidimensional data, the complexity of the data set itself may make adequate visualization difficulty limited dimensional spaces.

Data visualization objects in a virtual environment


A finger and toe nail repair kit and method wherein the kit comprises an adhesive which will both bond natural nail material and dissolve polystyrene, a multiplicity of polystyrene pellets, a cuticle stick, a buffing board with sufficient grit to grind a dried mixture of adhesive and polystyrene, and a buffing block to remove the shine from the nail after mending the nail and in preparation for a coating as desired. While the method comprises the placing adhesive directly in a crack or tear of a nail to be repaired, placing a polystyrene pellet longitudinally within the crack or tear while the adhesive is still wet, using the cuticle stick pressing the polystyrene pellet into the wet adhesive and crack or tear area allowing a portion of the pellet to be dissolved and become mixed with the adhesive and allowing the dissolved polystyrene and adhesive mixture to flow into the crack or tear, allowing the polystyrene and adhesive mixture to dry, removing the portion of the polystyrene pellet not dissolved by the adhesive, grinding the dried adhesive and polymer mixture to a desired level with the natural nail surface, buffing the nail surface to remove shine and prepare the nail for a desire coating.

Cracked or torn finger or toe nails have long been problems which are difficult to repair quickly and with sufficient strength. Improved adhesives and filling materials have allowed most cracked nails to effectively repaired, however these methods and materials are cumbersome to use because their components are not easily handled. Powered fillers and sticky adhesives are sometimes required to be mixed prior to use and then applied to the cracked nail, handling powders is extremely difficult and mixing the components takes time, while the mixing time or technique may vary resulting in inconsistent final products. Another problem with prior devices and techniques is the difficulty of directly applying the mixed filler and/or adhesive to the crack or the area to be filled. Prior art which has addressed these problems and others include the following:
Juhl et al., U.S. Pat. No. 5,638,837 which discloses a device which shields a portion of a finger nail to prevent nail polish from being applied to the shielded portion.
Rumore et al., U.S. Pat. No. 5,146,935 discloses a method for repairing finger nails which comprises a plurality of pre-sized nail patches which are ready to fit a damaged nail which assist in repairing nail cracks while a wrap is applied over the patch.
Aylott, U.S. Pat. No. 5,005,595 discloses a nail repair device for repairing split or broken finger nails which comprises a support portion for fitting under a nail and a handle portion extending from the support portion, the device supports a nail while the nail is mended with adhesive or the like.
Ferrigno, U.S. Pat. No. 4,450,848 discloses an artificial finger nail forming method and kit which comprises artificial finger nail tips, adhesive for adhering the artificial tip to the natural portion of the finger nail, and a finger nail leveling component comprising a first coat of adhesive followed by adding powdered acrylic ester polymer and then followed by another coat of adhesive over the powered polymer.
Nordstom, U.S. Pat. No. 4,249,551 discloses a finger nail reconstruction kit comprising a pair of containers for containing chemical components which are used for finger nail construction. The containers provide an easier means for dispensing the chemicals without spilling, dripping and exposing the chemicals to the atmosphere.
Turner, U.S. Pat. No. 3,228,404 discloses method for protecting, repairing and lengthening the life of fingernails by applying a coat of synthetic plastic cement over the entire exposed surfaces of the fingernail and then followed by a coat of cellulosic liquid material and then finally followed by a liquid sealer.
These prior devices are very useful for the particular problems they address, however they do not provide an effective means of applying fingernail crack repair material directly to and within the crack on the fingernail as the present device. The present invention overcomes the problem of applying impermeable polymers over the entire surface of a fingernail in order to repair a single crack. The present invention accomplishes this by supplying a repair kit which includes an adhesive which is applied directly to the damaged area of the fingernail, polystyrene filler pellets which are used to be pressed into the adhesive filled crack thereby dissolving a portion of the polystyrene pellet in contact with the adhesive so that the polystyrene and adhesive mix and flow into the crack and quickly harden, the undissolved polystyrene pellet portion is then broken off, the filled area is filed or ground to be level with the natural nail surface and then coated as desired. The present invention does not use a powdered component for filling avoiding the mess associated with mixing or handling powders.


A laundry detergent pod dispensing container includes a container, a connector plate, a dispensing mechanism, and a locking mechanism. The dispensing mechanism includes a top rotor assembly, a central rod, a fluctuating plate, a plurality of springs, and a bottom rotor plate. The central rod concentrically traverses through the connector plate as the top rotor assembly and the bottom rotor plate are terminally attached to the central rod. The fluctuating plate is concentrically connected to the connector plate by the plurality of springs and positioned in between the top rotor assembly and the connector plate. The locking mechanism is integrated between the top rotor assembly and the fluctuating plate. The locking mechanism enables rotation of the bottom rotor plate that selects and dispenses the laundry detergent pods. The connector plate is circumferencely attached to a rim of the container thus secularly storing the laundry detergent pods within the container.

Laundry detergent pods or packs are water-soluble pouches containing highly concentrated laundry detergent, softener, and other laundry products. The chemistry of laundry detergent packs is generally smiler to traditional liquid detergents. The dissolvable packets is typically made of polyvinyl alcohol (PVA) or a derivative of PVA. Laundry detergent pods were advertised as a way to reduce wasted use of powdered and liquid detergent by having precise measurements for a load. Additionally, laundry detergent pods are steadily becoming popular among consumers due to their individually packaging which reduces wastage. However, concern has been raised over children accidentally being exposed to laundry detergent packs, as its appearance and the packaging design can have the same appeal to a child as hard candy with patterned designs and be confused as such. Even though manufacturers have move towards safe packaging, re-focusing safe advertisements, improvements for storage containers, and less enticing appearance, injuries from laundry detergent pods have been increasing over the years. Furthermore, emergence of a viral Internet trend, called the "Tide Pod Challenge", which participants intentionally ingest laundry detergent pods, have also injured children and teens in recent years. Due to these hazards' incidents, there is a need for more advance and safe laundry detergent pod storage container.
It is there an objective of the present invention to provide a childproof laundry detergent pod dispensing storage container so that the manufacturers and/or consumers can safely store the laundry detergent pods. More specifically, the present invention enables the storage of the laundry detergent pods within a container as a connector plate and a locking mechanism restrict the dispensing of the laundry detergent pods. Each of the laundry detergent pods can be individually dispensed from the present invention as the locking mechanism selectively enables the operation of a dispensing mechanism of the present invention.

Laundry detergent pod dispensing container


External electrode terminal parts and a plastic terminal supporting body are individually formed, and the terminal parts are inserted into through holes of the terminal supporting body, thereby completing a terminal holder. Each of the terminal parts has a stopper portion at a predetermined position in its longitudinal direction, such that the stopper portion is wider than the width of the hole in the terminal supporting body. Hence, the distance between the terminal supporting body and the end of the terminal parts is defined when the terminal parts are inserted into holes of the terminal supporting body. In addition, since the terminal parts include a spring portion which abuts against the inner wall of the hole in the terminal supporting body when inserted therein, the terminal parts cannot slip out of the terminal supporting body. Since the terminal holder is formed by only inserting the terminal parts into the holes of the plastic terminal supporting body, the terminal parts cannot be deformed, and the terminal holder can be manufactured easily even if the number of terminal parts is large or the configuration thereof is complicated.

1. Field of the Invention
This invention relates to semiconductor device parts for use in a plastic packaged high-power semiconductor device and the like, and, more particularly, to semiconductor device parts comprising external electrode terminals and a terminal supporting body which is a portion of a package of the semiconductor device.
2. Description of the Related Art
FIG. 1A is a plan view showing the outer appearance of a plastic packaged high-power semiconductor device (G-TR Module) in general, and FIGS. 1B and 1C are partial cross-sectional front and side views, respectively, of the semiconductor device shown in FIG. 1A. In the device shown in FIGS. 1A to 1C, a semiconductor chip (not shown) is mounted on a circuit board 5 and electrically connected thereto by bonding wires. An electrode bed (not shown) for connecting electrodes to the external device is formed on the circuit board 5. A plastic terminal supporting body 1a and external electrode terminal parts 1b are formed integral with each other, constituting a terminal holder 1. The semiconductor device is formed as follows.
First, external electrode terminal parts 1b are placed in a plastic molding die, and plastic is injected into the die to form a terminal holder 1. Inner lead ends of the external electrode terminal parts 1b are adhered by solder 6 to the electrode bed on the circuit board 5. Next, a case 3, a heat radiating board 4, and the like are attached to the circuit board 5. To protect electronic circuits on the circuit board 5 from moisture, vibration, and the like, potting material 7 is injected into the case 3. Further, casting material 8 is injected on the potting material 7. In this way, a semiconductor device is completed as a product.
FIG. 2 is a perspective view showing the outer appearance of conventional semiconductor device parts (terminal holder 1). FIGS. 3A and 3B are partial cross-sectional front and side views, respectively, of the semiconductor device parts shown in FIG. 2. The external electrode terminal parts 1b for connecting an internal electrode on the circuit board 5 to an external device and the plastic terminal supporting body 1a are formed integral with each other by mean of plastic molding by use of a molding die. During the plastic molding, it is necessary to prevent plastic from being forced out through gaps between the molding die and the terminal parts 1b. For this purpose, the terminal parts 1b are fastened tightly by the molding die.
When the number of the external electrode terminal parts 1b are increased or when configurations of the terminal parts 1b are complicated, a complicated molding die must be used. As a result, it may be impossible to form the terminal parts 1b integral with the terminal supporting body 1a. In addition, due to the contacts between the terminal parts 1b and the molding die which occur when the terminal parts 1b are fastened by the molding die or due to the plastic injection pressure which is applied to the external electrode terminal parts 1b when the terminal parts 1b are molded, the external electrode terminal parts 1b tend to be deformed. When deformed defective terminal parts 1b are adhered to the circuit board 5 by a solder 6, the inner lead end 1b-1 of such defective terminal parts 1b cannot be perfectly adhered to the electrode bed. Thus, the defective terminal parts 1b-1 cannot be practically used. Since such defective terminal parts 1b lower the molding yield, the cost of manufacturing the terminal holder is inevitably increased.


A redundant electromechanical actuator is provided that includes first and second electric motors, a common output shaft, first and second drive cable drums, first and second driven cable drums, a first cable, and a second cable. The first and second electric motors are each adapted to be controllably energized to supply a drive torque. The common output shaft is coupled to receive the drive torque supplied from one or both of the motors. The first and second drive cable drums are coupled to the common output shaft to receive the drive torque from one or both of the motors. The first and second driven cable drums are each configured, upon being driven, to rotate. The first cable is coupled between the first drive cable drum and the first driven cable drum, and the second cable is coupled between the second drive cable drum and the second driven cable drum.

Actuators are used in myriad devices and systems. For example, many vehicles including, for example, aircraft, spacecraft, watercraft, and numerous other terrestrial and non-terrestrial vehicles, include one or more actuators to effect the movement of various control surfaces or components. In many applications such as, for example, aircraft flight surface control systems, missile thrust vector control systems, and submarines, the actuators that are used may be subject to relatively severe environmental conditions, as well as relatively high magnitude shock and vibration. For these reasons, as well as to ensure system availability for mission completion, it is desirable that at least some of the actuators that may be subject to such environmental conditions exhibit suitable redundancy.
For many of the above-mentioned applications, it is becoming increasingly desirable to use electromechanical actuators (EMAs). A typical EMA includes an electric motor that, when properly energized, supplies a torque to a suitable actuation device, which in turn positions a control surface or component. For at least some of the above-mentioned applications relatively small, lightweight actuators are desired. Moreover, relatively quiet actuators, with little or insignificant acoustic signatures may also be needed.
Hence, there is a need for an EMA that exhibits little or insignificant acoustic signature. The present invention addresses at least this need.

Redundant electromechanical actuator for control surfaces


There is provided a protection method and protection system for valuables. An internal enclosure for enclosing the valuables, an external enclosure for enclosing the internal enclosure, a misuse protection device for the valuables, and a triggering device for triggering the misuse protection device in the event of an unauthorized manipulation of the external enclosure are provided. The external enclosure is closable to form a seal. A pressure chamber, which is impinged by an initial pressure, is produced in the external enclosure. A setpoint pressure is generated, which deviates from the ambient pressure, in the pressure chamber when the external enclosure is closed to form a seal. A pressure sensor is used for detecting the pressure in the pressure chamber. The pressure sensor controls initialization of the triggering device. The triggering device triggers the misuse protection device when the pressure deviates by more than a tolerance pressure value from the setpoint pressure.

1. Field of the Invention
The present invention relates to a protection system for valuables including an internal enclosure for enclosing the valuables, an external enclosure for enclosing the internal enclosure, and a misuse protection device for the valuables, and an associated protection method.
2. Description of the Related Art
Valuables, in particular currency, must be protected continuously, i.e., during their storage and during transport. The valuables are typically enclosed in internal enclosures in the form of cassettes, as described, for example, in Swiss Patent Application 2005 00907/05. However, cases according to International Patent Application PCT/EP2006/050742 may also be used.
The term "enclosed" is not necessarily to be understood to mean that the internal enclosures and also the external enclosures cited below are lockable using mechanical, key-operated locks in the typical sense; the internal enclosures and the external enclosures may also be secured against opening in a closed and/or fastened form in another suitable way, in such a way that the valuables are encapsulated in a type of capsule whose interior is only accessible by suitable manipulations.
Such cassettes are usually stored in security devices during the storage of the valuables, for example, in a cash center or in a bank. Preferably, vehicles whose cargo spaces contain security devices for the cassettes are also used during transport using vehicles.
The danger of theft for the cassettes is especially high during transport between vehicles and buildings or on longer transport routes within building complexes. In order to protect the valuables and/or the internal enclosures and/or cassettes in this case, they are enclosed in special external enclosures, and a misuse protection device is provided, which is triggered in the event of unauthorized manipulations of the external enclosure. The misuse protection device may be situated in or on the internal enclosure and implemented for the purpose, for example, of marking and/or devaluing the valuables in such a way that they may not be misused. The misuse protection device may also comprise other measures such as an acoustic or visual warning signal, which may be detected on location or in a central office by monitoring personnel.
The external enclosures used up to this point and in particular their security units are complex to produce and are generally only capable of receiving cassettes having specific dimensions and a specific embodiment.
In particular, the outlay for mechanically protecting cassettes or transport cases against unauthorized access is becoming greater and greater. The cases are thus also becoming heavier and heavier and more and more expensive. The electronics used up to this point are also becoming more and more complex and thus also more complicated to handle.

Protection method and protection system for valuables


Disclose herein is an exhaust valve capable of quickly discharging either a fluid in a cylinder or compressed air in a pneumatic tank therefrom. The exhaust valve is basically provided with a first port, a second port, a third port and a directional control valve. The first port is supplied with a fluid and the second port is used to supply the fluid to another device or receive it therefrom. The third port is used to discharge the fluid therefrom and comprises a rotatable L-shaped line or pipe. The directional control valve is switched to cause the first port to communicate with the second port or cause the second port to communicate with the third port in response to the pressure of the fluid supplied from each of the ports. The first and second ports have axial directions respectively which substantially coincide with each other or extend approximately in parallel. Therefore, the first and second ports can be incorporated in the course of a pipe without making a change in a piping direction. Since the third port comprises the rotatable L-shaped line, the axial direction of the third port can be suitably changed to a desired direction.

1. Field of the Invention
The present invention relates to an exhaust valve capable of rapidly discharging, e.g., either a fluid in a cylinder or compressed air in a pneumatic tank therefrom.
2. Description of the Related Art
FIG. 1 shows a conventional exhaust valve. An exhaust valve 2 comprises a first body 4 and a second body 6. The first body 4 has first and second ports 8, 10 defined therein, which have screw threads respectively, and a hole 12 which communicates with the first and second ports 8, 10. The second body 6 has a third port 14 which is defined therein and has a screw thread, and a hole 16 which is defined in the leading end 18 of the second body 6 and communicates with the third port 14. A lip packing 22 having a sleeve 20 is disposed in the bottom of the hole 12 of the first body 4, and the second body 6 is fitted in the bottom thereof.
When a fluid is supplied from the first port 8, the exhaust valve 2 constructed in the above-described manner is actuated to displace the lip packing 22 in the direction indicated by the arrow A so as to be seated on the leading end 18 of the second body 6, thereby cutting off the communication between the hole 16 of the second body 6 and the hole 12 of the first body 4. Further, the sleeve 20 of the lip packing 22 is reduced in diameter by the pressure of the fluid supplied from the first port 8 so as to be opened, i.e., make a communication state, thereby making it possible to supply the fluid supplied from the first port 8 to the second port 10. When, on the other hand, the supply of the fluid from the first port 8 is stopped and the fluid is supplied from the second port 10, the pressure of the fluid acts on the sleeve 20 of the lip packing 22, that is, the outer diameter of the sleeve 20 increases so as to bring a peripheral edge of the sleeve 20 into abutment against an inner wall portion for defining the hole 12 in the first body 4, thereby separating the lip packing 22 from the leading end 18. Thus, the fluid supplied from the second port 10 is supplied via the hole 16 of the second body 6 to the third port 14.
When it is desired to dispose the exhaust valve 2 constructed as described above to a pipe coupled to a cylinder or the like, the first and second ports 8, 10 are connected to a fluid feed source and the cylinder respectively, and the third port 14 is open to the atmosphere. When the fluid is supplied to the cylinder under this connection, it flows into the second port 10 from the first port 8. When the fluid is discharged from the cylinder, it flows into the third port 14 from the second port 10 so as to be discharged into the atmosphere.
By disposing the exhaust valve 2 in the pipe coupled to the cylinder in the above-described manner, the a piping distance to an exhaust portion from which the fluid is exhausted can be reduced, thereby making it possible to quickly discharge the fluid and improve the response characteristic of the cylinder. Since the piping distance to the exhaust portion can be reduced, portions or ranges to which water or moisture adheres, can be reduced to a minimum.
However, the second port 10, when it communicates with a device such as the cylinder or the like to thereby supply the fluid to the cylinder and discharge it therefrom, is disposed at a right angle to the first port 8. Therefore, a pipe is limited to a so-called L-shaped line or tube. Thus, when the exhaust valve 2 is connected to a linearly pipe-arranged portion, a change in a piping direction should be carried out. The piping direction to the third port 14 is also restricted. Further, when a non-metallic member such as vinyl is used as a pipe, it cannot be connected to each of the first through third ports 8, 10, 14 which have been formed so as to be connected with a corresponding object by screw threads, and a connecting process becomes cumbersome.


The present invention discloses a generating method for short training field in IEEE 802.11n communication systems, mainly comprising the steps of: storing only a first set of time-domain HT-STF sequences in the memory; and deriving a second set of the time-domain HT-STF sequences from the first set of the time-domain HT-STF sequences. The first set of time-domain HT-STF sequences is the time-domain HT-STF sequences either for lower 20 MHz of 40 MHz BW or upper 20 MHz of 40 MHz BW. According to the invention, it is shown that only one set of time-domain HT-STF sequence needs to be stored in the memory. The other three sets of time-domain HT-STF sequence can be generated easily from simple calculation. Therefore, the saving in buffer size to implement all four configurations is significant.

1. Field of the Invention
The present invention generally relates to a packet-based generating method, and more particularly to a generating method for Short Training Field (STF) useful to IEEE 802.11n Wireless Local Area Network (WLAN) communication system.
2. Background Art
In a wireless communication system, the packet format normally includes a fixed-pattern preamble. The preamble serves several purposes, namely, to identify the packet type, and to provide signal for Direct Current (DC) offset estimation, frequency offset estimation and channel estimation. In most wireless communication systems, an important field of the preamble is High-Throughput Short Training Field (HT-STF).
The IEEE 802.11n draft specification [1] specifies four bandwidth (BW) configurations. The first one is a simple 20 MHz BW. The second configuration is 40 MHz BW. The third configuration is that a transmitter nominally operating in the 40 MHz BW mode may use the lower 20 MHz BW only to transmit. The fourth configuration is that a transmitter nominally operating in the 40 MHz BW mode may use the upper 20 MHz only to transmit. The HT-STF in each of these four configurations is mathematically derived from a different frequency-domain sequence, but the transmitter needs to transmit the corresponding time-domain sequence. A transmitter could store these frequency-domain sequences in the Read-Only Memory (ROM) and performs a Fast Fourier Transform (FFT) operation before transmitting the time-domain sequence. But a more efficient way is to store the time-domain sequence in the ROM. In this case, it is required to store all four sets of time-domain HT-STF sequences. Since there are 64 or 128 complex samples (real and imaginary parts) in HT-STF for each mode and a number of bits are required for each real or imaginary sample, the total buffer size becomes significant. If over-sampling is implemented at transmitter, the required buffer size will be further multiplied.
Several U.S. Patent Applications including: U.S. Patent Application 20060274852, entitled as "Modified preamble for programmable transmitter", Dec. 7, 2006; U.S. Patent Application 20060274847, entitled as "Training frames for MIMO stations", Dec. 7, 2006; U.S. Patent Application 20060193340, entitled as "Wireless messaging preambles allowing for beamforming and legacy device coexistence", Aug. 31, 2006; U.S. Patent Application 20060088120, entitled as "Mixed mode preamble for MIMO wireless communications", Apr. 27, 2006; U.S. Patent Application 20050286474, entitled as "Modified preamble structure for IEEE 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, MIMO or otherwise extended devices", Dec. 29, 2005; U.S. Patent Application 20050233709, entitled as "Modified preamble structure for IEEE 802.11a extensions to allow for coexistence and interoperability between 802.11a devices and higher data rate, MIMO or otherwise extended devices", Oct. 20, 2005; U.S. Patent Application 20050180360, entitled as "Preamble formats for MIMO wireless communications", Aug. 18, 2005; U.S. Patent Application 20050113026, entitled as "Frame format for high data throughput wireless local area network transmissions", May 26, 2005; and U.S. Patent Application 20050180368, "Multiple protocol wireless communications in a WLAN", Aug. 18, 2005; are prior arts claiming the format of HT-STF, and their intents are to become the essential patent for implementing IEEE 802.11n draft specification. However, none of these prior arts mentioned any methods of efficient generating method with reduced ROM requirement and simple arithmetic operations to generate all the time-domain HT-STF sequences for all four BW configurations.

Generating method for short training field in IEEE 802.11n communication systems


A heading transfer unit may be used to transfer a heading from a surface base to a MWD tool. The surface base may have a master north finder to determine a heading. The heading may be transferred to the heading transfer unit, which is in turn transferred to the MWD unit. The heading on the heading transfer unit is transferred to the MWD tool.

Current measurement while drilling (MWD) and gyroMWD techniques include a variety of sensors which are deployed into a borehole with a drilling assembly. These systems are designed to acquire headings on demand, and transmit these headings to surface via MWD telemetry (typically Mud Pulse or Electromagnetic). Standard MWD tools typically acquire headings using magnetic field sensors and acceleration sensors and, along with models of the Earth's magnetic and gravity fields, compute an instrument heading. Current gyroMWD techniques replace the magnetometers with a gyrocompass assembly, which uses a rate gyroscope to measure the direction of the Earth's rotation vector relative to the tool, and combine these with acceleration sensors (as in standard MWD tools) to compute an instrument heading. When using either method, the instrument must generally be kept still during the sampling period, to eliminate effects from movement and isolate acceleration due to gravity, and in the case of the gyroMWD method, to isolate Earth's rotation. Additionally, when using a standard MWD tool, the instrument can only be used when spaced sufficiently from external sources of magnetic interference (e.g. offset wellbores) to ensure that the modeled Earth's magnetic field is undisturbed.

Device and method for surveying boreholes or orienting downhole assemblies


In a powered tool for dimpling a drywall panel and driving a drywall nail through such panel, into a substrate, a dimpler mounted to a nosepiece of the tool so as to be axially movable over a limited range has an annular portion disposed axially beyond the nosepiece. The tool includes a piston and a driving blade joined to the piston and arranged for driving a drywall nail through the nosepiece and the annular portion, for engaging the annular portion near a distal end of the driving blade, and for driving the dimpler outwardly when the piston is impelled from a retracted position toward an advanced position. The annular portion has a frusto-conical bore. The driving blade has a frusto-conical tip fitting thereinto. A workpiece-contacting shoe is adjustable between a right-angled position relative to the drywall panel and an acute-angled position.

Pneumatically powered tools are used widely for forming dimples in workpieces, such as drywall panels, and for driving drywall nails or other elongate fasteners through such workpieces where formed with such dimples, into wooden studs or other substrates. Such tools are exemplified in Golsch U.S. Pat. No. 3,774,293 and Fishback U.S. Pat. No. 4,778,094.
Typically, such a tool employs a driving mechanism including a piston and a driving blade and having a high mass, along with a dimpler having a high mass and being shaped to form a dimple in the workpiece when struck by the driving mechanism. The dimple is a shallow recess, into which a nail is driven so that its head is countersunk. The dimple can be then filled with drywall finishing material, which conceals the nail head.
As exemplified in the patents noted above, it has been usual to arrange the driving mechanism and the dimpler so that the driving mechanism strikes the dimpler at a considerable distance from the workpiece.
In such a tool, as known heretofore, it is difficult accurately to control the depth of penetration of the dimpler into the workpiece because of the impact between the driving mechanism and the dimpler. The impulse of the impact therebetween can be calculated as ##EQU1## where V is the initial velocity of the driving mechanism before impact, m.sub.1 is the mass of the driver mechanism, and m.sub.2 is the mass of the dimpler.
Desirably, since it is difficult to reduce the mass of the driving mechanism, the mass of the dimpler should be low so as to reduce the impulse of the impact between the driving mechanism and the dimpler.

Powered dimple-forming and fastener-driving tool


A communication device is disclosed having optical and near-field communication capability. The device includes an optical transceiver circuit fabricated on an integrated circuit die and configured to transmit and receive far field signals. A near field transceiver circuit is also fabricated on the integrated circuit die and is configured to transmit and receive near-field electro-magnetic signals. Control circuitry is provided to selectively enable the optical transceiver circuit and the near field transceiver circuit responsive to an external control signal.

Infrared data communication is a known technique for short range data communications. The Infrared Data Association (IrDA) defines protocols for one example of an infrared communications scheme. An IrDA infrared communication transceiver typically provides 115.2 Kbp to 16 Mbs wireless transfer of data transfer over less than one meter. It uses a "point and beam" paradigm to transfer variable length data files; such as, speed directory lists on cell phones or PDA, MP3 files, pictures, or video clips. Although it is a wireless or cable replacement technology, IrDA is not suitable for networking like RF (Radio Frequency) IEEE 802.11 Wi-Fi or Bluetooth radio frequency protocols since it does not have sufficient range and only works within the +/−15 degree "point and beam" cone.
The following references provide additional background for the present invention. U.S. Pat. No. 4,763,340 for capacitive coupling type data transmission circuit for portable electronic apparatus. U.S. Pat. No. 3,265,972 for underwater electrical field communication system. U.S. Pat. No. 4,292,595 for capacitance coupled isolation amplifier and method. U.S. Pat. No. 6,141,592 for data transmission using a varying electric field. U.S. Pat. No. 6,336,031 for wireless data transmission over quasi-static electric potential fields. U.S. Pat. No. 5,621,913 system with chip to chip communication. U.S. Pat. No. 6,751,691 arrangement for data transfer between a computer and peripheral device or other data processing device. U.S. Pat. No. 6,612,852 for contactless interconnection system. U.S. Pat. No. 4,918,737 for hearing aid with wireless remote control. U.S. Pat. No. 5,437,057 for Wireless communications using near-field coupling. U.S. Pat. No. 4,061,972 for Short range induction field communication system. U.S. Pat. Nos. 5,864,591 and 6,240,283 for Feedback mitigation. Fazzi, A. et al; "A 0.14 mW/Gbps High-Density Capacitive Interface for 3D System Integration," Proceedings of CICC 2005 Conference, San Jose, pp. 101-104. Drost, R. et al. "Proximity communication," IEEE J. Solid-State Circuits, Volume 39, Issue 9, pp. 1529-1535, September 2004.
The following websites provide additional information regarding communications systems:
http://www.reghardware.co.uk/2006/04/19/nokia_cashless_bus_tickets/
http://www.nokia.com/nfc
http://www.theregister.co.uk/2004/07/22/aura_wireless/
http://www.auracomm.com/site/content/llla116.asp
http://www.sony.net/Products/felica/abt/dvs.html
http://www.research.ibm.com/journal/sj/353/sectione/zimmerman.html
http://www.evaluationengineering.com/archive/articles/1005/1005the_world.asp
http://www.eetasia.com/ART—8800412880—590626_a6f100b7200604.HTM

Apparatus and method for near-field communication


In an image pickup apparatus having a display unit that displays an image, an operation member to which a plurality of functions are assigned, and a detection unit that detects touching to the operation member, a display control for the display unit judges with use of the detection unit whether the operation member is touched, and controls, if touching to the operation member is detected, to display on the display unit the functions assigned to the operation member in an operational state of the image pickup apparatus when the touching to the operation member is detected.

1. Field of the Invention
The present invention relates to an image pickup apparatus provided with a display apparatus that displays captured images, and a display control method for the display apparatus.
2. Description of the Related Art
Conventionally, many image pickup apparatuses such as digital cameras assign a plurality of functions to each operation member according to the situation and the operational state of modes, in order to realize a large number of functions with a limited number of operation members. For example, forwarding and rewinding of playback images in playback mode and flash and macro settings in shooting mode may be assigned to a cross key. It is common in this case for function names or illustrations expressing the functions to be printed on or around the operation members, so as to make it easy for the user to tell what functions are assigned to the operation members (e.g., see PowerShot S500/410, DIGITAL IXUS 500/430, Camera User Guide, p.16).
However, with conventional digital cameras, the function names or illustrations expressing the functions printed on or around an operation member sometimes get hidden by user's fingers when holding the camera, making it difficult to tell what functions are assigned to the operation member.

Image pickup apparatus with display apparatus, and display control method for display apparatus


In accordance with the present invention there is provided a method for suturing tissue using a needle holder device, The device includes a handle for holding it, the handle has distal and proximal ends. The device also has right and left arms extending distally from the handle. The arms of the device have proximal ends attached to the handle and distal ends having grippers attached thereto for gripping and releasing a needle. The device includes at least one mechanism for moving the distal ends of the arms closely adjacent to one another and for passing the needle from one gripper to the other and thereafter for moving the distal ends of the arms further apart from one another. The right gripper is holding a needle having a suture attached thereto. The method first involves moving the distal ends of the arms apart from one another and manually inserting the needle into the tissue and back out again. Thereafter, the method involves actuating the mechanism so as to move the arms closely adjacent one another so that the left gripper holds the needle, the right gripper releases the needle. Then the method involves moving the distal ends of the arms further apart from one another. Lastly, the method involves removing the needle from the tissue.

It is common surgical practice to use bypass grafts to help reestablish coronary artery circulation when a portion of the coronary artery is stenosed. Such a procedure is typically referred to as a Coronary Artery Bypass Graft (CABG) procedure. Typically the graft vessel used in bypassing the stenosed portion of the coronary artery comprises one or more segments of the patient's saphenous vein which is taken from his leg. The saphenous vein is dissected free from the leg, its side branches tied off or ligated, and the vein removed. The vein graft is then washed free of blood, and cut into portions of suitable length. Each portion is then passed to the surgeon who trims the ends of the graft before anastomosing the graft to the aorta and the coronary artery. Other graft vessels such as the radial artery in the arm can also be used. In addition, it is common practice today for the surgeon to redirect one of the internal mammary arteries (IMA) in the chest to the stenosed portion of the left anterior descending (LAD) artery on the heart. The end of the IMA near the patient's diaphragm is transected, the artery is mobilized by dissection and ligation of side branches, and then the end is joined to the LAD, just distal to the blockage. For multiple bypass surgery, a combination of the redirection of the IMA and the grafting of vessels to the diseased coronary arteries is often used.
Some surgeons choose to complete all the proximal anastomoses to the aorta before commencing the distal anastomoses to the coronary arteries. In contrast, others choose to complete the distal anastomoses first. Regardless of the order, when undertaking the distal anastomoses to the coronary artery, it is important that the vessel graft be held steady and adjacent the coronary artery, with a minimum of vascular trauma and a minimum of visual and surgical obstruction by instruments in the narrow operative field.
The speed of performing such anastomoses can become extremely critical as well. Often the coronary artery is occluded during the procedure so that the anastomoses can be performed more easily. It is very important to reconnect the supply of blood to artery as soon as possible in order to minimize or prevent damage to the patient. Blood vessels are now normally anastomosed end-to-end or end-to-side by suturing techniques. Conventionally, to suture two vessels together, a surgeon passes the pointed tip of a curved suturing needle, having a suture attached to the blunt end, through the coronary artery wall from inside the lumen. The needle is then passed through the graft vessel wall from the outside. Then, the surgeon grasps the tip of the needle which has been forced through the tissues with fingers or a needle holder and pulls the needle through the tissues, the suture following the curved path of the needle. Usually a knot or button is present at the trailing end of the suture to anchor the first stitch. After the surgeon has pulled the suture entirely through the tissues to tension the first stitch, he or she then forces the tip of the needle through the coronary artery again, at a location spaced from the first stitch, until the needle again goes through the coronary artery and back out through the graft vessel. Again, he grasps the tip of the needle which has been forced through the tissues, applies tension to the needle pulls the entire suture through the tissues to complete the second stitch. This process is repeated again and again, with the surgeon tensioning the suture after each stitch to draw the tissues together thereby creating a running or continuous stitch, composed of individual thread loops, which extends around the graft vessel.
Needless to say, such suturing techniques are a tedious and time consuming ask. Suture anastomoses procedures generally take the skilled surgeon anywhere from ten to twenty minutes to complete for each anastomoses. An example of a device which was designed to help a physician in performing suturing can be found in U.S. Pat. No. 5,437,681 issued to Meade et al. on Aug. 1, 1995 and U.S. Pat. No. 5,540,705 issued to Meade et al. on Jul. 30, 1996, both of which are hereby incorporated herein by reference. However, there are a number of disadvantages to the device disclosed in those references. In those devices it is the device itself which drives the needle through the tissue. Many physicians do not like this design because they like to have more control of needle placement and feel the resistance of the needle passing through the tissue when doing the procedure. Surgeons want the speed and efficacy offered by the new devices, but also want to maintain the benefits of the traditional suturing techniques.
Presently, there are no known simple, yet foolproof, techniques for helping the physician perform the anastomoses more quickly and with greater precision than when using conventional instruments. The present invention provides a method which overcomes the shortcomings of the prior art and helps the physician to suture bodily tissues easily and quickly. It is especially useful for performing an easy and quick vascular anastomoses such as for a CABG procedure.

Method for using a needle holder to assist in suturing


A shower head designed to produce a consistent, wide diameter spray of water under both high and low water pressure conditions. The shower head includes a spinner tube mounted inside a cylindrical-shaped nozzle body. The upper segment of the spinner tube is held in a central location inside the nozzle body by a fixed cassette assembly. The middle and lower segments of the spinner tube extend below the cassette assembly and are bent outward and axially offset from the upper segment and from each other so that the spinner tube is able to spin freely inside the nozzle body. Mounted inside and over the upper end opening of the nozzle tube is an adapter with a longitudinally aligned threaded cavity formed on one end. The adapter includes a water orifice that delivers water from the shower head fixture tube to to the spinner tube. Disposed between the adapter and the upper end of the spinner tube is a flat washer with a narrow water orifice that delivers a narrow, high velocity stream of water to the spinner tube.

1. Field of the Invention
This invention pertains to shower heads and more particularly to shower heads designed to produce a wide, conical water spray pattern during low or high water pressure conditions.
2. Description of the Related Art
A wide variety of shower heads that provide pulsating or non-pulsating streams of water are known in the art. Most shower heads are also adjustable which provide a wide variety of flow patterns. Unfortunately, when the water pressure is relatively low (below 30 P.S.I.) the size of the spray pattern is destroyed.
Some shower heads design to create large spray patterns are relatively large structures comprised of large flat, circular structures with perforations or large bulbous structures with internal impellers or rotators that rotate or wobble when water flows through them. Unfortunately, many homeowners find large shower heads visibly distracting.


A reflective liquid crystal display device (LCD) (40) includes: a substrate (60), a reflecting layer (61), a liquid crystal layer (62), an electrode layer (63), a color filter layer (64), an upper substrate (65), and a polarizer (66). The reflective liquid crystal display device further includes a holographic field lens (67). By providing the holographic field lens, the LCD can be used with a closely placed, offset light source (41), since the holographic field lens simultaneously concentrates light incident on the LCD and redirects it in a preferred direction. The holographic field lens can be provided within the structure of the LCD.

The present application relates to a reflective display device such as a reflective liquid crystal display device (LCD). It particularly relates to a reflective display device having a light source to provide illumination, for example in poor light condition. It also relates to a light source, particularly but not necessarily for use with a display device.
Reflective LCDs are known in the art. For example, the xe2x80x9csuper-mobilexe2x80x9d high reflectivity LCD produced by Sharp Kabushiki Kaisha essentially comprises a polarizer, waveplates, and a liquid crystal layer disposed in front of a reflective layer. The reflective layer has a metallized non-symmetric surface relief structure, which substantially preserves the polarization of light incident on the reflective layer so as to maximize the contrast of the display. The reflective layer is a xe2x80x9chigh-gainxe2x80x9d reflective diffuser using a non-Lambertian surface relief structure.
Such a reflective LCD can use ambient light, so that the power consumption of the LCD is reduced compared to an LCD that comprises a light source provided behind the liquid crystal layer. This is important for portable display equipment such as a personal digital assistants (PDA), camcorders, portable computing equipment, and digital cameras.
Such a conventional reflective LCD does have a number of disadvantages. Clearly, the display will work poorly in dimly lit environments. Moreover, the color balance of the display will be influenced by the color spectrum of the ambient light. Thus, in sunlight, the display device may work well, but in fluorescent or particularly tungsten lighting, the color balance will be degraded. If the LCD is provided with color filters, these may also affect the color balance of the display.
A further disadvantage is that a high-gain reflective layer will work best when the light incident on the LCD is highly collimated overhead lighting incident on the screen of the LCD at a defined angle. Thus, the display position may have to be fixed by the user of the LCD to obtain the best performance, and this is undesirable. It can thus be seen that it would be advantageous to provide a reflective LCD with an auxiliary light source, to increase the quality of the displayed image and also to allow the LCD to operate in conditions of low ambient light.
As described above, a conventional reflective LCD has a reflective layer that is a high-gain reflective diffuser. If a light source is placed close to the surface of the LCD, a number of effects will be produced. First, the gain of the reflective layer will mean that the observer will see illumination structure across the surface of the LCD. This illumination structure will depend on the profile of illumination by the light source, and on the gain of the reflective layer.
Secondly, some light from the light source will be specularly reflected by the front surface of the LCD and from layers within the LCD. If the light source and a user are positioned such that light from the light source is specularly reflected towards the user, this will reduce the contrast of the display and will also be uncomfortable for the user. In order to prevent the user from seeing the specular reflection of the light source, the light source may have to be displaced laterally, i.e., offset, from the display surface. Displacing the light source in this way does, however, introduces a further problem. The LCD may well provide the highest display contrast for light within well-defined input and output cones. If the light source is displaced as described above, the input light may well no longer lie within the preferred input cone to the LCD and this will reduce the imaging efficiency.
FIGS. 1A and 1B show a prior art reflective LCD. Specifically, FIG. 1A is a cross-sectional view of a prior art reflection LCD device with a holographic element for brightness enhancement in front illumination, and FIG. 1B illustrates the incident and reflective light for the device of FIG. 1A.
The illustrated device is based on a glass substrate 1 on which are disposed, in sequence, a reflective layer (internal mirror) 2, a liquid crystal layer 3, color filters 4, an upper glass substrate 5, a polarizer 6 and a transmission hologram 7. Electrodes to drive the liquid crystal layer 3 are provided on the glass substrates 1 and 5.
The transmission hologram 7 is provided to enhance the brightness of the display. The LCD is illuminated by a distant light source, positioned at 34xe2x80x3 offset from the normal axis of the display as shown in FIG. 1B. Light that is specularly reflected from the front surface of the display, or from internal elements of the LCD, is reflected at an angle of 34xe2x80x3 to the normal to the display.
The transmission hologram 7 deflects light that is incident upon it. Thus, some of the light that passes through the liquid crystal layer 3 and is reflected by the reflective layer 2 is reflected back towards an observer much closer to the axis of the display than the specularly reflected light. As shown in FIG. 1B, the light from the display is reflected back at an angle of 14xe2x80x3 to the normal axis, whereas the specularly reflected light (xe2x80x9cglarexe2x80x9d) is reflected at 34xe2x80x3 to the normal axis. The brightness of the LCD is thus increased, since the display light is angularly separated from the glare.
The prior art display shown in FIG. 1A requires to be illuminated with a distant light source that appears collimated at the liquid crystal panel, and it would not function efficiently if the light source were close to the LCD.
U.S. Pat No. 5,663,816 discloses a transmissive LCD in which a reflective holographic directional diffuser is provided at the back side of the LCD. The holographic diffuser is transparent for illumination by a back light, but directionally reflects light when the LCD is illuminated by an external overhead source. The reflection is conical about the axis perpendicular to the reflection side of the LCD.
FIG. 2 shows a further prior art reflective LCD with a holographic light control film. This prior art LCD is disclosed in T. Hotta et al., SPIE Proc., Vol.329, Practical Holography XII, pages 190-195, 1998.
The LCD of FIG. 2 comprises a liquid crystal layer 15 which is disposed between two glass substrates 13, 17 provided with electrode layers 14, 16 for applying voltages to the liquid crystal layer 15. A first polarizer 12 is provided behind the lower glass plate (substrate) 13, and a second polarizer 18 is provided above the upper glass plate (substrate) 17. A volume reflection hologram (holographic light control film) 11 is provided behind the lower polarizer 12, to concentrate reflected light of a-single color into a specific viewing area (the prior art LCD shown in FIG. 2 is a monochromatic LCD).
In the prior art LCD shown In FIG. 2, the holographic film 11 is separated from the liquid crystal layer 15 by the lower glass substrate 13, and this will have a relatively large thickness. The spatial separation of the holographic film 11 and the liquid crystal layer 15 will introduce parallax into the display, and this will reduce the resolution of the LCD.
The prior art device described in U.S. Pat. No. 5,663,816 will also suffer from parallax problems.
U.S. Pat. No. 5,659,508 discloses an LCD viewable under ambient light comprising a liquid crystal panel, and a holographic reflective diffuser positioned behind the liquid crystal layer. The diffuser is made as a transmission hologram, and a light-reflective layer is deposited on the rear of the holographic diffuser. Such a holographic element is cheaper to manufacture as a broad band reflector than the other prior art holographic reflectors described above. However, the prior art device described in U.S. Pat. No. 5,659,508 again requires illumination with collimated light, and is not suitable for use with a closely positioned light source or with a high resolution color panel.
FIGS. 3A and 3B illustrate further prior art reflective LCDs. These are provided with polarization preserving optical diffusion films, so as to improve the performance and viewing angle of the display. Such polarization preserving films are manufactured by Microsharp.
The LCD shown in FIG. 3A comprises a glass substrate 20, a reflective pixel electrode 21, a liquid crystal layer 22, an indium tin oxide (ITO) electrode layer 23, a layer of color filters 24, a glass substrate 25. a Microsharp(trademark) transmission diffuser layer 26, a retardation film 27 and a polarizer 28.
The device shown in FIG. 3B is similar to that in FIG. 3A, but the Microsharp(trademark) diffuser 26 is omitted, and the reflective pixel electrode 21 of FIG. 3A is replaced by a transparent ITO electrode layer 21xe2x80x2. A polarizer 29 is further placed behind the lower glass substrate 20, and a metallized reflective diffuser 30 is placed behind the polarizer 29.
A transmission diffuser 26,30 is a relatively thick (100 xcexcm) plastic sheet with a random pattern distribution, selectable light diffusion profile, and a skew off-axis performance limited by 10xc2x0. The prior art devices illustrated in FIGS. 3A and 3B therefore require illumination with collimated light, and are not appropriate for use with a light source positioned close to the LCD. These devices have, moreover, a further disadvantage, since they produce a diffuse output, so that the contrast of the display will be low.
FIG. 4 illustrates a known projection LCD, which is described in C. Joubert et al., SPIE Proc. Vol.265, pages 243-252, 1996, and in C. Joubert et al., xe2x80x9cApplied Opticsxe2x80x9d, Vol.36, No.20, pages 4761-4771, 1997. The configuration of FIG. 4 includes a holographic microlens array for the LCD projection system.
The configuration of FIG. 4 has a full color liquid crystal display 31, which comprises red pixels 31R, green pixels 31G and blue pixels 31B. Light from a light source 32 is focused by a parabolic reflector 33 onto a holographic microlens array 34. Each individual element of the microlens array 34 is a transmission holographic lens which simultaneously disperses white light into RGB light components, and selectively focuses the dispersed RGB light components onto the corresponding color pixels (that is, the red component is focused on to a corresponding red pixel 31R, and so on). The holographic microlens array 34 is acting as both a lens and a diffraction grating.
The holographic microlens array 34 of FIG. 4 requires off-axis illumination by a well-collimated white light source having a divergence of less than 1.9xc2x0. Such an element is not suitable for illumination by a diverging light source that is positioned close to the LCD.
FIGS. 5A and 5B illustrate, respectively, a plane view and a top view of a prior art light source for illuminating a bar code. This prior art light source is described in U.S. Pat. No. 5,743,633. It includes a light emitting diode (LED) 35, a light shaping diffuser 36 and a lens 37. The light shaping diffuser 36 is a holographic surface diffuser, which produces a strip-shaped area of uniform illumination.
The illumination system of FIGS. 5A and 5B provides uniform illumination over a target area 38 of a bar code (i.e., a target uniformly illuminated area 38), by homogenizing and concentrating light from the LED 35.
WO 95/12826 discloses a reflective liquid crystal display device 500 as schematically shown in FIG. 5C, which includes a transmissive liquid crystal panel (transmissive SLM) 510 and a reflective holographic element (diffuser) 520 disposed behind the liquid crystal panel 510. When diffuse light or substantially collimated light is incident on the LCD 500, the holographic element 520 transforms the off-axis collimated beam into a collimated beam that is propagating substantially on-axis. Each point of the holographic element 520 of the LCD 500 of WO95/12826 has the same Bragg angle.
WO97/34174 and WO96/37805 both disclose a reflective display device provided with a holographic element. In both cases, the holographic element functions as a diffuser, and is intended to provide even illumination of the display and to increase the brightness of the display. These prior art documents are directed to eliminating the need to provide an auxiliary light source.
U.S. Pat. No. 5,594,560 discloses a reflective display device that is provided with a reflective holographic optical element. The holographic element is provided to enhance the brightness of the display, and the device incorporates a fluorescent layer in order to increase the spectral band of the hologram.
G. T. Valliath et al., xe2x80x9cDesign of Hologram for Brightness Enhancements in Color LCDsxe2x80x9d, SID DIGEST 98, pages 1138-1142 discloses a reflective display device comprising a transmissive holographic diffuser diffused in front of a reflective spatial light modulator. In use, the device is again illuminated with an off-axis beam of collimated light, and the holographic diffuser transforms this into a collimated beam propagating substantially on-axis. Each point of the holographic diffuser has the same Bragg angle.
The present invention provides a display device comprising: a spatial light modulator having an optical modulation layer; and a reflector disposed behind the optically modulating layer, and further comprising a holographic field lens.
A holographic field lens is a holographic optical element disposed substantially in the image plane of the display device, and which has optical power and re-direction properties Thus, a holographic field lens can convert an incident beam of diverging light to a beam of collimated light, and can also re-direct the incident light. Whereas the hologram layer 7 in the prior art device of FIG. 1A simply deflects the incident light, and so requires an incident beam of collimated light, the holographic field lens of the present invention simultaneously concentrates incident light and redirects it in a preferred direction, and may be used with a close, offset light source.
The present invention will function when the display device is illuminated with diverging light, as will be the case when it is illuminated by a nearby light source, but this will not be the case for the prior art device of FIG. 1A.
The reflector may be disposed within the spatial light modulator. This prevents problems from arising owing to parallax.
The reflector may be a non-Lambertian reflector. This increases the intensity of light reflected by the reflector.
The holographic field lens may collimate off-axis diverging light incident on the holographic field element. In this case, the display device functions as if it was illuminated with a virtual source of collimated light.
The collimated light may be directed at an angle xcex8 to the normal axis to the display, wherein xcex8 is greater than half the acceptance angle of the holographic field lens. This prevents light reflected back to the holographic field lens from interacting with the holographic field lens. The angle xcex8 may be xcex8xe2x89xa730xc2x0.
The holographic field lens may be a holographic microlens array. The display device may further comprise color filters, wherein the pitch of the holographic microlens array is substantially three times the pitch of the color filters. When such a device is illuminated with white light, the white light is split, with red light being directed to a red color filter, green light to a green color filter, and blue light to a blue color filter, respectively. Since the pitch of the microlens array is three times the pitch of the color filters, manufacturing tolerances for the microlens array are eased.
The holographic field lens may be disposed in front of the optical modulation layer. Alternatively, the holographic field lens and the reflector may be formed in a single element.
The holographic field lens may be disposed within the spatial light modulator, and the holographic field lens may be positioned close to the optical modulation layer. This reduces the loss of contrast that would be caused by hologram scatter. The holographic field lens may be separated from the optical modulation layer, to prevent holographic materials from contaminating the liquid crystal layer.
The display device may further comprise a light source, wherein the light source is arranged to illuminate the spatial light modulator with diverging light. This enables the display device to be operated in low ambient light.
The light source may be offset with respect to the spatial light modulator, so that specularly reflected light is not reflected towards a user.
The display device may further comprise a homogenizer disposed between the light source and the spatial light modulator. The homogenizer will shape the profile of the light beam from the light source to correspond with the shape of the spatial light modulator. It will also make the intensity uniform over the beam and thus over the display device. The homogenizer may be a holographic homogenizer. It may be a reflective holographic homogenizer, such as a reflective volume holographic homogenizer.
The light source may be substantially monochromatic, or it may be a white light source. Alternatively, the light source may comprise at least a first light source emitting light at a first wavelength and a second light source emitting light at a second wavelength. This allows the color balance of light from the light source to be adjusted, for example to suit the color filters used in a full color display device.
The light source may be a light emitting diode. Alternatively, the first light source may comprise a first light emitting diode for emitting light of the first wavelength, and the second light source may comprise a second light emitting diode for emitting light of the second wavelength. A light emitting diode is a low power device, and so is advantageous for use in a portable, battery powered display device.
The diffraction efficiency of the holographic field lens may vary over the holographic field lens. The diffraction efficiency of the holographic field lens may be lower at a side of the spatial light modulator near the light source and higher at a side of the spatial light modulator away from the light source. This improves the uniformity of the intensity of the display.
The holographic field lens may be chromatic, and the first and second light sources may be disposed at the respective foci of the holographic field lens for the light of the first wavelength and the light of the second wavelength, respectively.
The display device may further comprise a cover member, wherein the light source is disposed on the cover member. This is a simple way to provide a display device with a light source for use in low ambient light. Alternatively, the display device may further comprise a support member for supporting the light source, and the support member may be movable between a stowed position and a position in which the light source is able to illuminate the spatial light modulator.
The optical modulation layer may be a liquid crystal layer.
A second aspect of the present invention provides an illumination system comprising at least one light source, and a holographic homogenizer disposed in the path of light from the light source(s).
The holographic homogenizer may be a reflective holographic homogenizer.
The holographic homogenizer may alternatively be a transmissive holographic homogenizer. The illumination system may further comprise a reflector, wherein the transmissive holographic homogenizer is disposed between the at least one light source and the reflector.
The illumination system may comprise first, second and third light sources for emitting light at a first wavelength, a second wavelength and a third wavelength, respectively, wherein the first, second and third light sources are disposed in a linear array. The linear array of light sources is disposed at an achromatic angle to the holographic homogenizer.
The illumination system may comprise first, second and third light sources for emitting light of a first wavelength, a second wavelength and a third wavelength, respectively, wherein the light sources are arranged in a substantially triangular configuration.
Each of the at least one light source may be a light emitting diode.

Reflective display device and a light source for a display device