An exposure apparatus for exposing a shot region on a substrate includes a movable stage, a projection optical system, a measuring device configured to measure a position of a partial region of a surface of the substrate, and a controller configured to cause the measuring device to measure the position with respect to each of a plurality of measurement points of each of a plurality of shot regions, to determine a global shape of the surface based on the measured positions, to calculate a correction value with respect to each of the plurality of measurement points based on the determined global shape, and to move the stage based on measurement values corrected using the respective correction values corresponding to the respective measurement points.

1. Field of the Invention
The present invention relates to an exposure apparatus for use in the manufacture of devices, such as semiconductor devices, and to a method for manufacturing a device.
2. Description of the Related Art
In general, an exposure apparatus that forms the image of a pattern on a mask or reticle (hereinafter referred to collectively as a "reticle") on a photosensitive substrate via a projection optical system is used in a lithographic process of the manufacture of semiconductor devices, a liquid crystal display device, a thin-film magnetic, or other devices. With the advance of finer pattern rules and higher packaging densities of an integrated circuit, it is desired for an exposure apparatus that the image of a circuit pattern on a reticle be projected onto the surface of a substrate with higher resolution to expose the surface. The resolution in projecting the image of a circuit pattern depends on the numerical aperture (NA) of a projection optical system and wavelength of exposure light. Typically, a method of increasing the NA of the projection optical system using a constant wavelength of exposure light is performed. The wavelength of exposure light is being reduced more and more. For example, the wavelength of exposure light is shifting from the g-line to the i-line to the oscillation frequency of an excimer laser. For the excimer laser oscillation frequency, the wavelength of exposure light is being reduced from 248 nm to 193 nm, and further to 157 nm. Moreover, the size of an exposure area is increasingly becoming larger.
One example of means for accomplishing these requirements is a stepper that projects light onto a substantially square exposure region of the surface of a substrate so as to form a reduced pattern image thereon and exposes the surface by the step-and-repeat process. Another example of such means is a scanning exposure apparatus that exposes a larger area of a substrate accurately by relatively scanning a reticle and the substrate with high speed using an exposure region that has a rectangular or arc slit shape, a so-called scanner. Such a scanner adjusts a surface shape of the substrate to an optimal exposure image-plane position for each scanning exposure slit, so the scanner has the advantage of reducing the influence resulting from the degree of flatness of the substrate. The scanner also can increase the size of the exposure region and the NA even with a lens equivalent to that used in a stepper. As a result, the scanner is becoming the dominating exposure apparatus. The scanner adjusts the surface of the substrate to an exposure image-plane position for each scanning exposure slit in real time. Thus, before the scanner reaches the exposure slit position, the position of the surface of the substrate is measured with a surface position measuring device and the driving is corrected. The oblique-incidence-light measurement technique is commonly used as the surface position measuring device. In the oblique-incidence-light measurement technique, a beam of light is made to be obliquely incident on the surface of the substrate, and a change in the position of a reflection point of light reflected from the surface of the substrate is measured as the amount of change in the position on a position sensor. The position of the reflection point on the surface of the substrate is referred to as a measurement spot. A plurality of measurement spots are present in the longitudinal direction of the exposure slit, i.e., a direction substantially perpendicular to the scanning direction to measure both the height and the inclination of the surface.
In FIG. 11, three measurement spots are present both in front and behind a scanning exposure slit 900, i.e., measurement spots 901, 902, and 903 and measurement spots 904, 905, and 906 are present in front and behind, respectively. In FIG. 12, five measurement spots are present both in front and behind the scanning exposure slit 900, i.e., measurement spots 907, 908, 909, 910, and 911 and measurement spots 912, 913, 914, 915, and 916 are present in front and behind, respectively. Having a focus measurement system both in front and behind enables scanning for exposure to be performed both from the front and rear directions in FIGS. 11 and 12, thus allowing focus measurement of the substrate to be performed before exposure. A twin-stage exposure apparatus, as illustrated in FIG. 1, has a focus measurement system that has many measurement spots 4a aligned in a line, as illustrated in FIG. 2, aside from an exposure system to find the surface of a substrate 4 in advance. It is necessary to reliably place an entire area to be exposed of the substrate 4 within the allowable depth of focus of a reduction projection optical system, the allowable depth of focus being reduced with an increase in NA. One example method for achieving this aim is disclosed in Japanese Patent Laid-Open No. 9-045608. In this method, the influence caused by local pattern steps (asperities) is eliminated or reduced, and a global shape of the surface is determined. For each measurement spot, the difference between a measurement value (height) and a corresponding value (height) obtained from the global shape the measurement value is determined as a correction value for the measurement value.
With recent expansion of networking technologies, the demand for high performance, such as high integration, reduction in a chip size, speed enhancement, and low power consumption, on a large-scale integration (LSI) is becoming increasingly great. To address the demand, as a result of advancement of finer design rules and multi-layering in conformance with the international technology roadmap for semiconductors (ITRS), a new problem also arises. With finer design rules, the previous process extension techniques could not facilitate speed enhancement of an LSI because they cause an increase in signal delay in an interconnection layer. The delay time in interconnections is proportional to the interconnect resistance and the capacitance between interconnections. Therefore, to advance achieving higher performance, it is necessary to reduce the interconnect resistance and the capacitance between interconnections. Resistance reduction by use of copper interconnections is becoming popular as one way of addressing the interconnect delay time problem. To reduce the capacitance between interconnections, it is necessary to reduce a dielectric constant of an interlayer dielectric. A typical method for reducing the dielectric constant is to introduce holes (the relative dielectric constant is one) to a heat-resistant material. This is called porosification. Copper interconnections are typically formed by a Damascene process because it is difficult to form copper interconnections by dry etching, which has been widely used in other interconnections. In the Damascene process, trenches for interconnections are formed on an interlayer dielectric in advance, and a copper coating is deposited thereon. Then, the copper other than that sunken within the trenches is removed by chemical-mechanical polishing (CMP) to form copper interconnections. In this process, if the mechanical strength of a porous interlayer dielectric is too low, the film is frequently peeled or destroyed inside the film by the stress in CMP. One measure to address this is a method of increasing the mechanical strength by embedding a dummy copper interconnect pattern in a porous interlayer insulating film. The dummy copper interconnect pattern is embedded such that the mechanical strength is uniform over the entire area of the surface of the substrate.
As previously described, the light measurement technique is commonly used as the surface position measuring device of the exposure apparatus. It has been found that the surface position measuring device using the light measurement technique has measuring errors in cases described below. When interference occurs between light reflected from the surface of the resist applied on the substrate and light reflected from the surface of the substrate after having passed through the resist, measuring errors arise. When there is a pattern formed on the surface of the substrate in a front-end process, if light reflected from the surface of the substrate has a distribution according to the distribution of reflectivity of the pattern caused by the influence of the pattern, measuring errors also occur. For either interference or reflectivity, the ratio of the intensity of light reflected from the pattern to the intensity of light reflected from the substrate is increased, thus resulting in a relative increase in the amount of measuring errors. This influence arises when a reflectivity distribution partially varies within a measurement spot region. In addition to a decrease in the depth of focus caused by finer design rules, an increase in the influence of interference caused by a reduction in the film thickness of a resist, and the use of interconnections having high reflectivity, such as copper interconnections, make influence of errors resulting from a reflectivity distribution within the surface of a substrate larger, compared with in the prior art.
An example of the influence of a reflectivity distribution on focus measuring will now be described with reference to FIGS. 5A and 5B and FIGS. 6A and 6B. FIGS. 5A and 5B are diagrams that illustrate the substrate 4 with a resist 503 applied thereon. A pattern 501 is formed in a front-end process and has a high reflectivity. The pattern 501 can be made of, for example, metal. A pattern 502 can be formed from, for example, an interlayer dielectric. The pattern 502 has a reflectivity lower than that in the pattern 501. A beam 504 having a constant beam diameter and uniform intensity distribution within the beam diameter is incident toward the substrate 4. The beam 504 is reflected from the surface of the resist 503, that of the pattern 501, or that of the pattern 502, thus forming reflected beams 505 or 506, each of which exhibits an intensity distribution varying within the beam diameter.
FIGS. 6A and 6B are graphs of intensity distributions in a state where the reflected beams 505 and 506, which are reflected from the surface of each of the resist 503, the pattern 501, and the pattern 502, are focused on a photo detector. In FIGS. 5A and 5B, the beam 504, which has a constant beam diameter and uniform intensity distribution within the beam diameter, is divided into two kinds of components described below. One is components 510 and 511 reflected from the surface of the resist 503. The other is components 512 and 513. The components 512 and 513 have passed through the resist 503, reflected from the surface of the pattern 501 or 502, and gone out of the resist 503 again. That is, each of the reflected beams 505 and 506 includes a combination of the component 510, which is reflected from the surface of the resist 503, and the component 512, which is reflected from the surface of the pattern 501, and a combination of the component 511, which is reflected from the surface of the resist 503, and the component 513, which is reflected from the surface of the pattern 502. Therefore, in FIGS. 5A and 5B, when the ground reflectivity of the pattern 501 is larger than that of the pattern 502, each of the reflected beams 505 and 506 exhibits an intensity distribution 602 varying within a beam diameter, as illustrated in FIGS. 6A and 6B. FIG. 5A corresponds to FIG. 6A, and FIG. 5B corresponds to FIG. 6B. The intensity distribution within the beam diameter of a reflected beam varies according to the position of a pattern arranged within the beam diameter of an incident beam. The surface position measuring device using the light measurement technique is set using a position detecting device (e.g., a charge-coupled device (CCD)) such that the position of a barycenter 601 of a reflected beam that exhibits an intensity distribution varying within the beam diameter is measured as the position of incidence of the reflected beam on the device. At this time, when the substrate lies in the same location, the position of the barycenter of a reflected beam does not vary in normal times. However, because the patterns 501 and 502 are present on the substrate, the barycenter 601 of the intensity distribution of the reflected beam varies depending on a relative positional relationship between the incident beam and the patterns 501 and 502, as illustrated in FIGS. 6A and 6B. Therefore, the measurement values have inherent detection errors according to the arrangement of the patterns 501 and 502. That is, detection errors inherent in a process where pattern structures are different occur. For the same reason, when the pattern 501 is a pattern that allows a beam to pass therethrough, for example, an interlayer dielectric, an interference state with the pattern 502 that does not allow a beam to pass therethrough is changed. Thus, even if they have the same ground reflectivity, the reflectivity is changed by the interference. Also in this case, where such a phenomenon occurs, the barycenter 601 of the intensity distribution of the reflected beam varies, as illustrated in FIGS. 6A and 6B.

Exposure apparatus and method for manufacturing device


A siding trim clip having a substantially N-shaped profile is formed having a first gripping portion and a second biasing portion. The gripping portion includes a curved upper arch having an interior with opposing inwardly and upwardly oriented gripping fingers, arranged for accepting and securing an edge location of a siding member by way of a triangular gripping pattern. The biasing portion includes a lower inverted arch and linear portions for providing an outward biasing of the edge location of a siding member to hold it away from a wall structure and up against an outside edge of a pre-established finishing cavity. This abstract is provided to comply with rules requiring an abstract, and is submitted with the intention that it will not be used to interpret or limit the scope and meaning of the claims.

Siding systems useful for providing a protective and aesthetic covering are well known in the art, and are often available in a number of differing types. For example, as shown in FIG. 1, the siding members 104 may be structured to look like traditional lap boards. Alternately, another common siding choice, as shown in FIG. 2, provides a textured cedar simulated siding member. As depicted in FIGS. 1 and 2, the actual siding members include an upper panel interlocking portion 108a, which is structured to mate with a lower panel interlocking portion 108b. For the first piece, a starter piece 110 is employed and includes slots or holes 114. First the starter piece 110 is attached to the wall structure 90 using fasteners 112, as depicted. Next a first course of siding members, 104 or 104-1, are installed upon the wall structure 90.
As understood by skilled persons, one issue that arises with the installation of common and ubiquitous vinyl and synthetic siding, is the need to secure upper edge locations which have often been trimmed (e.g., cut to fit the wall structure). For example, such an arrangement typically occurs at a vertical stop location, such as under pre-hung windows and under over-hangs of common residential and commercial structures.
One common approach employed by siding technicians, which is simple and relatively low cost, involves the use of point-location applications of silicone sealant at somewhat equally spaced locations along the edge location to be secured. The siding technician would simply load up a finishing trim piece such as J-channel with a 'blob' of silicone, say every 12 to 18 inches. Next the panel would be installed, relying on the interlocking bottom portion to initially hold the panel up while the blob of silicone dries. Although a simple technique, involving no additional mechanical and or mating pieces, this solution does not provide a firm holding of the panel, especially during severe weather conditions such as those involving high wind speeds.
When considering common sidings, they can be made of a thin material, say having a thickness of 1/32 of an inch to ¼ of an inch. The prior art provides a variety of trim clip structures for certain (generally flexible and thin) siding materials. For example, the trim clip of Champagne (U.S. Pat. No. 5,537,791) may be best suited for use with thin and ubiquitous common double-siding members. However, trim clips such as those taught by Champagne can be somewhat complicated, often having a number of sharp bends, which are substantially folds of material, along with several additional sharp obtuse angle bends. A major issue is known to arise with trim clips such as those taught by Champagne, especially when they are employed with thicker siding materials. Essentially, the sharp bends employed to assure an effective gripping of an edge location of a thinner siding member, makes prior art trim clips (e.g., Champagne) difficult to use—if not functionally inoperative—when used with thicker versions of common vinyl and synthetic siding members. In addition, prior art trim clips such as the Champagne' clip, employ a limited grasping/gripping arrangement wherein typically only one line of gripping fingers is applied to each side at the edge to be secured. This provides a less than optimal gripping arrangement that is quite susceptible to rocking, and which is notably improved upon by the 'triangular gripping pattern' employed with embodiments of the present invention.
Accordingly, there is a need for an improved trim clip, wherein the clip may be used with a variety of siding panel members having differing thicknesses and textures. Further, it would be helpful to have a trim clip that does not employ sharp bends and or folds, which tend to be rigid and or somewhat less flexible, while also possibly compromising the material at the location of the fold/sharp bend. It would also be desirable to have a plurality of gripping fingers that are most preferably arranged to engage the edge location of a siding panel member to be secured using at least three (3) lines of fingers—most preferably gripping the edge of the panel in a triangular gripping relationship or pattern. A number of other characteristics, advantages, and or associated novel features of the present invention, will become clear from the description and figures provided herein. Attention is called to the fact, however, that the drawings are illustrative only. In particular, the embodiments included and described, have been chosen in order to best explain the principles, features, and characteristics of the invention, and its practical application, to thereby enable skilled persons to best utilize the invention and a wide variety of embodiments providable that are based on these principles, features, and characteristics. Accordingly, all equivalent variations possible are contemplated as being part of the invention, limited only by the scope of the appended claims.

Siding trim clip with triangular gripping pattern


A method and a robotic device for locomotion training. The method involves shifting a subject's pelvis without directly contacting the subject's leg, thereby causing the subject's legs to move along a moveable surface. The device comprises two backdriveable robots, each having three pneumatic cylinders that connect to each other at their rod ends for attachment to the subject's torso. Also provided is a method of determining a locomotion training strategy for a pelvic-shifting robot by incorporating dynamic motion optimization.

1. Field of Invention
This invention relates generally to a method and device for controlling the stepping motion of a subject undergoing locomotion rehabilitation.
2. Related Art
In the U.S. alone, over 700,000 people experience a stroke each year, and over 10,000 people experience a traumatic spinal cord injury. Impairment in walking ability after such neurologic injuries is common. Recently, a new approach to locomotion rehabilitation called body weight supported (herein referred to as "BWS") training has shown promise in improving locomotion after stroke and spinal cord injury (6, 19). The technique involves suspending the patient in a harness above a treadmill in order to partially relieve the weight of the body, and manually assisting the legs and hips in moving in a walking pattern. Patients who receive this therapy can significantly increase their independent walking ability and overground walking speed (2). It is hypothesized that the technique works in part by stimulating remaining force, position, and touch sensors in the legs during stepping in a repetitive manner, and that residual circuits in the nervous system learn from this sensor input to generate motor output appropriate for stepping. The continued development of BWS training provides paralyzed patients with the hope of regaining at least some degree of mobility.
Clinical access to BWS training is currently limited because the training is labor intensive. Multiple therapists are often required to control the hips and legs. Several research groups are pursuing robotic implementations of BWS training in an attempt to make the training less labor intensive, more consistent, and more widely accessible (3, 7, 12). Implementing BWS training with robotics is also attractive because it could improve experimental control over the training, thus providing a means to better understand and optimize its effects.
One robotic device for locomotion training is the Lokomat, which consists of four rotary joints, driven by precision ball screws connected to DC motors, which are mounted onto a motorized exoskeleton to manipulate a patient's legs in gait-like trajectories (5). Another device is the Mechanized Gait Trainer (MGT), which comprises two foot plates connected to a double crank and rocker system that is singly actuated by an induction motor via a planetary gear system and drives a patient's legs in a walking pattern (8). The ARTHuR robot makes use of a linear motor and a two degree-of-freedom mechanism to measure and manipulate leg movement during stepping with good backdriveability and force control (13). Other devices under development include HealthSouth's Autoambulator, and a more sophisticated version of the MGT that can move the footplates along arbitrary three degree-of-freedom trajectories.
These initial gait-training devices have focused primarily on controlling leg movement. However, torso motion also plays an important role in normal locomotion. The MGT has taken the simplified approach of moving the torso with a single mechanism along a fixed trajectory that approximates the vertical trajectory achieved during normal stepping. Such a fixed trajectory cannot be optimal for every patient. In addition, this approach requires the same torso motion to be applied regardless of the stage of recovery of the patient. The Lokomat restricts horizontal and pelvic rotation motions, and simply allows the patient to move up and down without controlling the up-and-down motion. In gait training, patient-specific torso motions may be useful for generating desired gait patterns (18). Thus, a device that manipulates the torso would enhance the flexibility of BWS training.
Robotic devices for gait training preferably exhibit good backdriveability, defined as low intrinsic endpoint mechanical impedance (10), or accurate reproduction at the input end of a mechanical transmission of a force or motion that is applied at the output end (15). Good backdriveability offers several important benefits for robotic therapy devices (13), including the ability for the device to act as a passive motion capture device. In such a passive motion capture mode, the patient's movement ability can be quantified, and the therapist can manually specify desired, patient-specific training motions for the device.
One difficulty in automating BWS training is that the required patterns of forces at the hips and legs are unknown. For example, the relative importance of assisting at the hip and leg is unclear. One approach toward determining the required forces is to instrument the therapists' hands with force and position transducers (3). However, therapists are relatively limited in the forces that they can apply compared to robots, and there is no guarantee that any given therapist has selected an optimal solution.
An alternate approach toward generating strategies for assisting in gait training is dynamic motion optimization. Dynamic motion optimization provides a formalized method for determining motions for underconstrained tasks, and may reveal novel strategies for achieving the tasks. It has been used with success to simulate human control over such activities as diving, jumping, and walking (1, 9, 11).

Robotic gait rehabilitation by optimal motion of the hip

The Regents of the University of California


An X-ray image intensifier tube includes a scintillator screen for converting ionizing radiation into light radiation or near-visible radiation, a microchannel array for achieving electron multiplication, and a photoelectrode positioned directly on an input face of the microchannel array. The input face of the microchannel array is coated with an electrically conductive layer which directly contacts the photocathode. The present design eliminates strict spacing requirements between the photocathode and the microchannel array and allows the photocathode and the microchannel array to operate at a single potential rather than requiring separate potentials. The requirement of a separate support for the scintillator screen is also obviated since the scintillator screen is formed on the input face of the microchannel array.

1. Field of the Invention
The invention relates to image intensifier tubes of the type wherein, firstly, an incident ionizing radiation is converted into photons in the visible or near-visible range and, secondly, an array comprising microchannels is used to achieve a gain in electrons.
2. Description of the Prior Art
Image intensifier tubes such as these are commonly used in the fields of radiology, and especially in X-ray diagnosis, where they are called X-ray or radiological image intensifier tubes (or also "IIR" tubes).
The principle of a radiological or X-ray image intensifier tube is well known. It is illustrated schematically in FIG. 1, by a sectional view of an X-ray image intensifier tube 1.
The X-ray image intensifier tube 1 comprises a vacuum-tight chamber, constituted by a central body 2 with a shape generated by revolution positioned about a longitudinal axis 3. The body 2 is closed at one end by an input window 4 and at the other end by an output port 5.
Incident X-rays penetrate the X-ray image intensifier tube through the input window 4 which, for this purpose, should be as transparent as possible to these rays: the window 4 is generally constituted by a thin metal foil of aluminium or tantalum or glass etc.). An appropriate shape and appropriate mechanical characteristics give the window 4 mechanical resistance that is sufficient to withstand the atmospheric pressure exerted from the exterior to the interior of the tube.
The X-rays then encounter a set called a primary screen 15 which converts the incident X-radiation into electrons that are sent out into the vacuum from the point at which this radiation is absorbed. The primary screen is generally constituted by a "sandwich" which successively comprises: a support 6 that is transparent to X-rays, a layer 7 of scintillating material that converts the X-ray radiation into radiation of lower energy, generally in the form of visible light, and a photocathode 8, deposited on the scintillator 7, that sends electrons out into the vacuum under the effect of the radiation emitted by the scintillator.
The scintillator support 6 should be transparent to the X-rays: it is generally constituted by a thin sheet of metal or silica-based glass, etc.
The scintillator 7 is often constituted by layer of caesium iodide having a thickness of the order of 0.2 to 0.8 mm.
The photocathode 8 is formed by a layer of a photoemissive material generally having a very small thickness (often smaller than one micrometer).
The X-ray image intensifier tube 1 further includes a set or system of electrodes 10 set to potentials (not shown) suited to the accelerating and focusing of all the electrons emitted by a same point of the photocathode 8 on a homologous point of a luminescent screen 11 located on the output port 5 side. This system of electrodes is called the electronic optical system of the X-ray image intensifier tube 1.
The luminescent screen 11 is formed by a layer deposited on a transparent support 12, located inside the tube and behind the output port 5. It is thus possible, through the output port, to observe the converted visible image of the X-ray image which has been projected on the primary screen 15 through the input window 4 of the tube.
In an X-ray image intensifier such as this each incident X photon of primary energy ranging from 30 to 100 kV, absorbed in the scintillator 7, typically gives rise to several thousands of light photons and, thereby, to the emission of several hundreds of electrons into the vacuum, the quantum yield of the photocathodes 8 generally ranging from 10% to 20%.
Each of these electrons, accelerated at a voltage of 10 to 30 kV, in turn prompts the sending out of several hundreds of light photons in bombarding the luminescent screen. Each X-ray photon absorbed by the primary screen 15 is thus converted into a number of light photons close to 10,000, emitted by the luminescent screen 11.
Furthermore, the electronic optical system of the tube generally concentrates the output image on a far smaller format than that of the input image, typically a format equal to 1/10 to 1/5. This is accompanied by a major gain in luminance for this output image. The reduction of the image also means that the 1 mm details on the primary screen are reduced to about 1/10 mm on the luminescent screen, and that the image resolution required at the level of the luminescent screen is thus far greater than that detected at the primary screen.
The photon gain, and the gain in luminance provided by the reduction, make it possible, with radiological doses that can be borne by the patient, to obtain an output image that is luminous enough to be observed and recorded by means of a cinema camera or a television camera, in constituting radioscopic systems that work in real time.
In second and third generation light image intensifier tubes (image intensifiers in which the incident radiation is in the form of visible light and which therefore comprise no scintillator), there are known ways of adding an array of microchannels in order to further increase the electron gain. However, in X-ray image intensifier tubes such as those shown in FIG. 1, the photon gain is considered to be sufficient in practically every application, and it is generally not deemed to be necessary to increase it by adding a microchannel array, although assemblies such as these have already been proposed.
However, the use of a microchannel array in X-ray image intensifier tubes to replace the electronic optical system is considered to be likely to show great advantages such as, for example, great reduction in thickness, namely in the distance between the input window and the output port; uniform resolution on the entire image field (even for large-sized images); the possibility of making it far easier to obtain square or rectangular formats that are better suited to the formats of usual images or of television screens.
X-ray image intensifier tubes using a microchannel array instead of the electronic optical system are often called X-ray image intensifier tubes with dual proximity focusing. Tubes such as these are described notably in I.C.P. Millar et al., "Channel Electron Multiplier Plates in X-Ray Image Intensification", in Advances in Electronics and Electron Physics, Vol. 33, Academic Press, 1972. In the X-ray image intensifier tube described in this publication, the primary screen is plane. It is stretched in parallel to and at a small distance from the input face of the microchannel array, while the luminescent screen is placed in parallel to the output face of the array, and at a small distance from said array. To prevent the dispersal of the electrons, firstly between the photocathode and the input of the array and, secondly, between the output of the array and the luminescent screen, from causing deterioration in the resolution, very small distances, typically of less than 1 millimeter, have to be maintained between the electrodes.
FIG. 2 gives a schematic view of an X-ray image intensifier tube such as this, of a type similar to the one described in the above-mentioned publication.
As in the example of FIG. 1, the X-ray image intensifier tube 20 comprises a tube body 2 positioned about a longitudinal axis 3. The body 2 is closed at one end by an input window 4 and at the other end by an output port 5.
The incident X-rays penetrate the tube 20 by the input window 4 and then encounter a primary screen 21.
Unlike in the primary screen 15 of FIG. 1, the primary screen 21 of this version is plane. It has a scintillator support 22, a scintillator 23 and a photocathode 24 which may be of a same nature and which fulfil the same functions as the support, the scintillator and the photocathode shown in FIG. 1.
The electrons (not shown) emitted by the photocathode 24 are directed by an electrical field towards the input face 26 of a microchannel array 25. To this effect, a first biasing potential and a second biasing potential V1, V2 are applied respectively t the photocathode 24 and to the input face 26, the second potential V2 being more positive than the first potential V1.
The array of microchannel array 25 is an assembly of a multitude of small parallel channels or microchannels 27 separated by partitions 28, and assembled in the form of a rigid plate. Each primary electron (sent out by the photocathode) that penetrates a microchannel 27 is multiplied by a phenomenon of secondary emission in cascade on the walls of the microchannel, so that the electron current at the output of the array can be more than a thousand times greater than the electron current at input. The diameter d1 of the microchannels may range from 10 to 100 micrometers. The microchannels 27 are inclined with respect to the normal to the plane of the array so that electrons emitted by the photocathode 24 in parallel to this normal cannot emerge from a microchannel without having given rise to a phenomenon of secondary emission. In order to reduce the number of electrons that strike the input face 26 of the array 25 outside the microchannels, it is the usual practice to make a widened or flared portion 30 at the entrance to these channels and hence to reduce the thickness of the partition walls 28. The thickness E of the plate that forms the microchannel array 25 is typically between 1 and 5 mm. The electronic gain of the array may be adjusted over a wide range of values, for example between 1 and 5000, as a function of the voltage developed between the input face 26 and an output face 31 of this array 25, namely an output face 31 to which a third biasing potential V3 is applied.
The input face 26 and the output face 31 are each covered with a metallization layer, M1, M2 respectively (represented in FIG. 2 in dark lines) through which the potentials V2, V3 are distributed over the input and output faces. Naturally, these metallizations M1, M2 should not block the microchannels 27. It must be noted that it is common practice to deposit the metallization layers M1, M2 on the walls of the microchannels 27 at the ends of these microchannels, i.e. at the input and at the output of these microchannels. Generally, the metallization layers M1,M2 are deposited on the input and output faces 26, 31 of the microchannel array by a method of vacuum evaporation of a conductive material (such as, for example, chromium, nickel-chromium, Iconel etc.,) by Joule effect in using, most often, an electron gun to sublimate the metal to be evaporated.
This technique is a standard one. To limit the penetration of the metal into the channels 27, the evaporation is done at a glancing incidence ("slantwise").
Furthermore, the microchannel array is supported, during the evaporation, on a system of planet wheels which make it possible, by continuous rotation, to expose the surface of the array to the metal flow in every direction while, at the same time, preserving the glancing incidence. The penetration of the metal into the channels 27 is thus uniform, for each channel and for all the channels.
The electrons at output of the array of microchannels are accelerated and focused by an electrical field, on a luminescent screen (35) positioned so as to be facing the array, parallel to this array, and at a distance D of the order of 1 to 5 mm. The luminescent screen 35 has dimensions substantially equal to those of the primary screen. It locally emits a quantity of light proportional to the incident electron current, and it therefore restores a visible and intensified image of the X-ray image projected on the scintillator, through the input window of the tube. The luminescent screen 35 is a layer with a thickness of several micrometers, constituted by grains of luminophor material, and it may be deposited on the output port 5. The face of the luminescent screen 35, pointed towards the array 25 of microchannels, is coated with a very thin metal layer 36, made of aluminium for example. This metallization enables the electrical biasing of the screen (by the application of a fourth potential V4 that is more positive than the third potential V3) and acts as a reflector for the light reflected rearwards by this screen.
The primary screen 21 and the array 25 of microchannels are fixedly joined to the body 2 of the tube, for example by means of lugs 29 sealed to this body. To these lugs, there are furthermore applied the biasing potentials V1, V2, V3. The primary screen 21 and the slab 25 are thus fixed so as to be electrically insulated from each other while, at the same time, being separated by a relatively small distance D1 of the order of some tens of millimeters (it must be noted that, for greater clarity, the figures have not been drawn to scale).
A structure of a X-ray image intensifier tube such as this is difficult to manufacture, especially for large-sized images. It is indeed difficult to make a perfectly plane primary screen and to maintain it in a position parallel to the microchannel array, at a very small, uniform distance. However, this is necessary to limit the angular dispersal of the electrons (an effect which reduces the spatial resolution) and to obtain efficient resolution of the image on the entire field.
Another difficulty arises out of the fact that the scintillator 23 and its support 22 do not have the same expansion coefficients: they are both constituted by thin layers that tend to get deformed, and lead to a deformation of the photocathode and hence to a local modification of the distance between this photocathode and the microchannel array.
These difficulties are all the more pronounced as the dimension of the X-ray image intensifier tubes is great, whereas the applications envisaged for an X-ray image intensifier tube with a microchannel array (namely an X-ray image intensifier tube with dual proximity focusing) calls for large useful surface areas, typically with a diameter of over 15 cm, or equivalent surface areas in rectangular formats.

X-ray image intensifier tube having a photocathode and a scintillator screen positioned on a microchannel array


A seamless frequency hopping system utilizes a programmable digital signal processor with interface circuitry in conjunction with a frequency hopping radio to incorporate the concepts of audio time compression, hop by hop automatic gain control and time repeating squelch to improve the sound of frequency hopped analog communication. Incoming uncompressed audio is first sliced into time segments that each correspond to one frequency hop. The uncompressed audio is then compressed to a certain percentage of its original length in time. A dead time as well as a pilot signal is added to the front of the audio. The processed audio signal is then sent to the radio where it is modulated and broadcast. A second radio receives the incoming signal and demodulates it to once again become an audio signal.

1. Field of the Invention
The present invention is related to communication systems and more specifically to reducing interference while communicating by utilizing frequency hopping.
2. Description of the Prior Art
In any electronic communication system there is a certain amount of interference which must be controlled. This interference can be any electrical or electromagnetic disturbance, phenomena, signal, or emission, man-made or natural, which causes or can cause an undesired response, malfunctioning, or degradation of the electrical performance of electrical equipment. To reduce or eliminate this interference or jamming there are several prior art techniques. One such prior art technique is to utilize frequency hopping.
Several problems are associated with frequency hopping, however. First, the audio signal is chopped with a dead time that occurs at the beginning of each hop. Second, the signal strength varies from hop to hop. Finally, certain channels are already occupied with a strong signal that can drown out the hopping signal. These three phenomena are known as hop noise and can be very distracting.
It is an object of the present invention to avoid the deficiencies of typical frequency hopping as well as the deficiencies of other prior art noise elimination techniques and to provide an improved communication system in which the operator will not notice a change in the audio output from single frequency operation to frequency hopping operations.


A method for facilitating real-world interaction includes receiving information regarding geographical positions of a plurality of client devices, determining that a subset of the plurality of client devices are within a given distance of each other, matching a face detected in an image captured by one of the plurality of client devices to facial data stored in a user database, and providing, to the one of the plurality of client devices, information regarding a user associated with the facial data.

Social media plays a larger and larger role in our lives; increasingly, members of our society interact with family, friends, co-workers, and acquaintances on-line via web browsers, mobile applications (from their smartphones, tablet computers, or similar devices), or other means. Many very successful web sites and services exist to facilitate this on-line interaction, including FACEBOOK, TWITTER, FOURSQUARE, VINE, and many others. Many of us use these services and value the virtual friendships that they allow.
These on-line services, however, at best do not help real-world interactions between people, and may in fact hider them. Increasingly, we retreat to our on-line personas and shrink away from real-world interaction. An older generation may, perhaps, have developed the social skills, confidence, and assuredness to (for example) walk into a room full of strangers and be at ease; they may have the social confidence to approach, speak to, or otherwise engage new people. Younger people, on the other hand, may have never known life without social media, and without its support, may struggle in traditional, in-person, real-world interactions with others.
Social media is here to stay. Efforts to withdraw from it, or eliminate it, are futile; those who wish for the end of social media as a means to cultivate traditional, in-person interaction will fail. A need therefore exists for a way to cultivate and facilitate real-world, in-person interaction that embraces and leverages existing paradigms of social media.

Social interaction using facial recognition


A new and improved external corner protector is fabricated from predetermined materials and comprises a vertex portion, and a pair of leg members which diverge outwardly at a predetermined included angle with respect to each other from the vertex portion. The vertex portion and distal end portions of the leg members have relatively enlarged cross-sectional dimensions relative to the cross-sectional dimensions comprising those portions of the leg members which integrally interconnect the distal end portions of the leg members to the vertex portion, wherein the relatively enlarged cross-sectional dimensions serve to reinforce the vertex portion and to dispose only such relatively enlarged distal end portions of the leg members into contact with the external side wall members of the palletized load which define the external corner region being protected. In this manner, the leg members of the external corner protector are flexed more than has conventionally been the case such that forces are generated and transmitted to the vertex portion so as to rigidify the same whereby the vertex portion will exhibit enhanced flexural strength and bending resistance properties with respect to external forces which may be impressed upon the external corner protector thereby tending to flex or bend the same.

External package, article, product, or palletized load corner or edge protectors, corner post supports, and the like, are of course well-known in the packaging, shipping, and transportation industries, and are accordingly widely used in connection with the packaging, shipping, and transportation of various packages, articles, products, palletized loads, and the like, wherein it is particularly desirable to protect the external corner or edge portions or regions of the packages, articles, products, palletized loads, or the like, during transit. Typical or conventional external corner or edge protectors, which may be used upon various packages, articles, palletized loads, products, and the like, are disclosed, for example, within U.S. Pat. No. 5,918,800 which was issued to Goshorn et al. on Jul. 6, 1999, U.S. Pat. No. 5,385,236 which was issued to Cowan et al. on Jan. 31, 1995, U.S. Pat. No. 5,181,611 which was issued to Liebel on Jan. 26, 1993, U.S. Pat. No. 4,877,673 which was issued to Eckel et al. on Oct. 31, 1989, U.S. Pat. No. 4,742,916 which was issued to Galea on May 10, 1998, and U.S. Pat. No. 4,202,449 which was issued to Bendt on May 13, 1980. As can readily be seen from, for example, the aforenoted patents to Goshorn et al., Cowan et al., Liebel, Eckel et al., and Bendt, after the external corner or edge protectors have been conventionally applied to, or mounted upon, the external corner or edge portions of a particular palletized load, package, article, product, or the like, the external corner or edge protectors are subsequently secured upon the package, article, product, palletized load, or the like, by means of suitable package strapping, lashing, stretch film, ropes, bands, or the like. It can therefore be appreciated that, in order to preserve the structural integrity of the strapped or banded package, article, product, palletized load, or the like, it is imperative that the structural integrity of the external corner or edge protector is itself preserved in connection with, for example, flexural or bending forces which are oriented or impressed upon the external corner or edge protectors in directions substantially perpendicular to the longitudinal axis, or longitudinal extent, of the external corner or edge protectors by means of the aforenoted strapping, lashing, ropes, stretch film, bands, or the like. If this was not the case, that is, if the structural integrity of the external corner or edge protectors was not in fact preserved, and was in fact compromised, then obviously, the utility or usefulness of the external corner or edge protectors, with respect to the protection of the external corner or edge portions of the packages, articles, products, palletized loads, or the like, would likewise be compromised.
Continuing further, various factors influence or determine the flexural properties, or flexural strength or resistance values, characteristic of an external corner or edge protector. For example, one critically important factor which influences or determines the flexural properties, or flexural strength or resistance values, characteristic of an external corner or edge protector, comprises the material from which the external corner or edge protector is fabricated, and in addition, whether or not such external corner or edge protector has a solid or substantially hollow structure. For example, as can be appreciated from the aforenoted patent which was issued to Liebel, the corner post disclosed within such patent is fabricated from laminated paperboard, and in addition, the corner post has a paperboard spine, which substantially comprises a hollow structure formed by folding end portions thereof back upon themselves, secured to the external surface of the corner post per se. In view of the fact that the corner post and spine components are fabricated from paperboard, their flexural resistance properties would probably not be as high as may be expected if the corner post and spine components were fabricated from other more rigidified materials, and in addition, if such structural components were exposed to moist conditions, which may develop or prevail within different cargo holds, or as a result of having particular products disposed internally within the packages, palletized loads, or the like, the structural integrity of the corner post and spine components could be jeopardized.
Still further, the fact that external corner or edge protectors may be fabricated from other materials may likewise provide such external corner or edge protectors with desirable shock absorption or cushioning properties, but, again, they may not provide such external corner or edge protectors with the desired flexural resistance properties. It is seen, for example, that the external corner or edge protectors of Galea are fabricated from molded fiber or pulp material, while the external corner or edge protector of Cowan et al. is fabricated from a combination of a soft thermoplastic material, such as, for example, low density polyethylene, for its cylindrical members, and a rigid thermoplastic material, such as, for example, high density polypropylene, for its connecting web members. As can therefore be readily appreciated, not only is the particular type of material, from which the external corner or edge protector structural components are fabricated, critically important in connection with the various structural and lifetime service qualities exhibited by the external corner or edge protectors, but in addition, the amount and weight of the material required to fabricate such external corner or edge protector structural components is also a critically important factor to be considered from a manufacturing cost-effective or economically viable point of view. It would therefore be desirable to fabricate an external corner or edge protector which could not only exhibit, for example, flexural strength or bending resistance qualities which would be comparable to those of conventional external corner or edge protectors, but in addition, could effectively be fabricated with a predeterminedly reduced amount of material or weight, or alternatively, it would be desirable to fabricate an external corner or edge protector which, for a predetermined amount of material and weight, could exhibit flexural strength or resistance properties which would exceed those of conventional external corner or edge protectors.
A need therefore exists in the art for a new and improved external corner or edge protector, for protecting the external corner or edge region of a package, article, product, palletized load, and the like, wherein the amount of material that is required in connection with the manufacture or fabrication of such an external corner or edge protector could be substantially reduced as compared to conventional external corner or edge protectors, but still further, the external corner or edge protector would be provided with unique and novel structure which would not only serve to protect the external corner or edge region of the package, article, product, palletized load, and the like, but in addition, could achieve levels of structural integrity and flexural strength or bending resistance which would be comparable to those of conventional external corner or edge protectors, or alternatively, wherein the amount of material that is required in connection with the manufacture or fabrication of such an external corner or edge protector would be substantially the same as that of conventional external corner or edge protectors, however, the unique and novel structure of the external corner or edge protector would enable enhanced levels of structural integrity and flexural strength or bending resistance to be achieved.

Corner or edge protector exhibiting improved flexural strength and resistance properties


A communication unit (10) with dual-mode operating capability comprises: a receiver (203, 204) and a transmitter (207, 208) for supporting an initial connection with another communication unit (12) on a first wireless network (16, 18, 20); and a controller (205), coupled to and controlling the receiver and transmitter, to maintain the initial connection and receive messages from or send messages to the other communications unit to effectuate a new connection over a second wireless network (11). A corresponding method includes while participating in an initial connection (302) detecting availability of a new connection (304) and establishing the new connection by exchanging messages between the communication units over the initial connection (310, 312).

1. Field of the Invention
The present invention relates generally to mobile communication units and networks, and, more particularly, to a method and apparatus for providing a hand-in for such mobile communication units between networks.
2. Description of the Related Art
Loosely coupled Wireless Local Area Networks (WLAN) defined by enterprise servers provide users with high-speed wireless Internet access and an inexpensive alternative to telephone services as well as other real-time applications. The users can carry a wireless communication unit (referred to as a communication unit) with dual-use capability so that the communication unit can provide voice and data communication over the enterprise server when the communication unit is in a WLAN (in a coverage area and registered with the WLAN) and over a cellular wide area network (cellular network) such as any of the cellular networks when the communication unit is outside of the WLAN.
When the user is moving between different networks such as, for example, from a cellular network to the WLAN, while on a call, the call must be handed-in to the WLAN without a disruption in communication unit service. This is difficult because the necessary switching equipment is in the cellular base transfer site associated with the cellular network. What is needed is a method and apparatus for providing a hand-in for a communication unit during an on-going call when the communication unit moves between different networks.

Method and apparatus for providing a hand-in to a wireless local area network


A photovoltaic device utilizing a gain means and an amplification means to intake and convert incident light/photons to greater intensities of highly coherent and monochromatic photons whereby said photons are passed to a resonating means and absorption means, allowing for said photons to be absorbed with increased conversion efficiency.

Photovoltaic cells are a promising energy harvesting technology. Photovoltaic or solar cells provide a means to convert light and generally abundant sun light to electricity. Photovoltaic cells operate on the general principle where light, which in the physical sense is a flux of photons, excites one or more electrons from its valence band to a conduction band in a semiconductor. These electrons are then harvested and stored in a battery or capacitor, or can be used to drive a load. Prior incremental improvements in photovoltaic cell efficiency came at the expense of exotic materials or manufacture of the device. Unfortunately, the present technology is challenged by its inefficiency and thereby renders fossil energy resources economically attractive.
U.S. patent application No. 2005/0155641, by Fafard et al. and titled Solar Cell with Epitaxially Grown Quantum Dot Material, describes a photovoltaic solar cell comprising a plurality of subcells. While the device utilizes Distributed Bragg Reflectors and mentions the use of reflectivity to change the absorption properties, the patent application fails to describe how this can be accomplished. In addition, the patent application neither describes the use of Distributed Bragg Reflectors to trap and recycle light, nor the use of a quantum gain medium to create resonance and thereby a feedback system.
U.S. patent application No. 2005/0247339, by Barnham et al. and titled Method of Operating a Solar Cell, describes a device for the method of operating a solar cell. The invention requires greater than 30 quantum wells within two pieces of bulk semiconductor and requires highly concentrated sunlight on the order of 30-100 suns. While a DBR is incorporated on the bottom of the cell to reflect unused photons back through the device, the invention fails to disclose a resonating means whereby a photon is recycled. In light of the prior art there is a need for . . . .

Photovoltaic device employing a resonator cavity


A method of fabrication of a fiber bundle termination with reduced fiber-to-fiber pitch which includes reducing the outside diameter of fibers in the fiber bundle by etching and provides means for preventing breakage of the etched fibers during etching and assembly. A high yield fabrication and assembly process is described.

Modern information systems require a high speed data transmission. Fiber optical systems provide a high bandwidth and are widely use in communication systems. Fiber optic bundles are commonly utilized in fiber optical systems to increase the communication bandwidth. Many methods of creating fiber bundles exist. They include crimping, tie cables, insertion of fibers into ferrules, etc. Of particular interest are the efforts to reduce fiber-to-fiber pitch because many applications require or benefit from fiber bundles having a small fiber-to-fiber pitch. For example, a liquid crystal beam steering-based 1×6 fiber optical switch, which inherently utilizes a small steering angle, requires fiber bundles with fiber-to-fiber pitch of 50 μm or less to operate. In another example, in MEMS (Micro Electronic Mechanical System) micromirror-based switch, the beam deflection angle is proportional to micromirror's tilt angle. A fiber bundle with smaller fiber-to-fiber pitch requires a smaller micromirror tilt angle which would reduce driving voltage, thus increasing system's reliability and reducing its power consumption.
Another example is a fiber coupler (such as power monitoring tap coupler), that couples light from one fiber to other fibers. In a fiber coupler assembly, a lens is usually used to couple the light into fibers. A fiber bundle with reduced fiber-to-fiber pitch results in fibers being closely packed at the optical axis of the lens which improves device's coupling efficiency.
Circulators, variable optical attenuators, wavelength selective switches, reconfigurable optical add/drop modules, chromatic dispersion compensators, etc. also benefit from utilizing fiber bundles with reduced fiber-to-fiber pitch.
Typical single mode fibers have an inner core (active area) diameter of about 9 micrometers (μm) and an outside diameter of 125 μm. In order to produce a fiber bundle with a reduced fiber-to-fiber pitch, the fiber outside diameter has to be reduced.
A reduction of the outside diameter of the fibers also results in an increase of the packing fraction of the fiber bundle, which is defined as the ratio of the information-carrying cross-sectioned area of the fiber bundle (fiber cores) to the total cross-sectioned area of an endface of the fiber bundle. The increased packing fraction of the fiber bundle is beneficial for applications where increased density of light is important.
A method of reducing fiber outside diameter is disclosed in the U.S. Pat. No. 3,912,362 to Hudson, hereinafter referred to as '362 patent. The '362 patent discloses fiber bundle termination where fibers are etched and inserted into a ferrule and secured to each other and the ferrule by adhesive. The '362 patent discloses fibers with an inner active core having a large diameter. The inner core diameter of processed fibers disclosed in '362 patent is 3.6 mils, which is equivalent to about 91.4 μm, and an outer diameter of those fibers equal to 5.5 mils (139.7 μm). The '362 patent teaches etching the fibers to reduce the outer diameter to 3.8 mils (96.5 μm). Because the after-etch diameter of the fibers was still very large, fiber breakage was not a concern, and special means to prevent breakage of the fibers were not required.
Accordingly, a need exists to create a fiber bundle with a fiber-to-fiber pitch smaller than 50 μm for fibers having small inner core diameter, typically in the range of about 3.5 μm to about 10 μm. That requires the after-etch fiber outside diameter of less than 50 μm. Fibers with small outside diameter are extremely fragile and are very difficult to handle. This problem is overcome by the hereinafter disclosed fabrication method that stabilizes the fibers and reduces the possibility of breakage associated with a small after-etch fiber outside diameter.

Fiber bundle termination with reduced fiber-to-fiber pitch


A wideband communications system uses a photomixer, a radio frequency (RF) mixer, and an antenna. The photomixer is comprised of high speed phototransistors that are illuminated by two laser beams. The laser beams are generated by two lasers, one tunable, and conveyed to the photomixer via fiber optic cables. The two beams are mixed by the photomixer to generate a radio heterodyne signal that is mixed with antenna signals to generate an intermediate frequency (IF) signal based on the differences of the generated heterodyne frequency and the antenna signals. Conventional fiber optic means may be used to convey the IF signals, along with the fiber optic cables to the photomixer, to and from a remote RF head located at some distance from the rest of the communications system to overcome losses in transmission lines.

This invention relates to communications systems, microwave communications systems, and specifically an electro optic microwave communications system.
As the information age has grown, the availability of wireless bandwidth has been seriously constrained by available spectrum. The obvious growth path, as spectrum becomes fully occupied or oversubscribed, is to move upward in frequency to unused bandwidth. The upper frequency limit has steadily risen to where the use of the millimeter and terahertz (THz) spectrum is now realistic. Building radio frequency (RF) circuitry for these frequency ranges is very difficult and expensive and in particular a unique system must be built for each sub-band. No known technology exists for generation (transmit) and reception (receive) of signals across multiple sub-bands or indeed across the entire band (up to 1 THz). Various absorption holes exist in the THz frequency range and hence useful communications is possible in these holes. Government surveillance systems are already vitally concerned with signal activity in this range and are hampered by the lack of RF technology to prosecute such signals.
The state-of-the-art today finds commercial communications up to 67 gigahertz (GHz), and military uses to 94 GHz and beyond. Much experimentation is underway in the terahertz range, and various specialized users are already demanding receive capability in the 100- to 300-GHz range. From a pure atmospheric attenuation perspective shown in FIG. 1, it can be seen that there are several low-attenuation bands at 140, 240 and 560 GHz usable for free space communications. Many uses, however, do not rely on low-attenuation bands, and can utilize any terahertz frequency for deliberate limited range communication.
Current technology is slowly evolving toward an expanded set of block converters, each using a unique technology optimized to a particular frequency band to cover the terahertz frequency range. Typically, the block converter includes an antenna, preamplifier and mixer driven by a fixed, multiplied local oscillator. Two or more block converters may be used in cascade.
What is lacking is the technology to implement a continuous-tuning communications or surveillance system that covers the 20–500 GHz band, similar to the common availability today of receivers that cover 20–520 megahertz (MHz).

Electro optical microwave communications system


A method of forming a through silicon via includes forming a via opening in a substrate using a hard mask, wherein a polymer is formed in the via opening. A first wet clean removes a first portion of the polymer and forms a first carbon containing oxide along portions of the sidewalls. A first ash process modifies the first carbon containing oxide and removes a second portion of the polymer. A first wet etch removes the modified first carbon containing oxide and a third portion of the polymer. A second ash process forms a second carbon containing oxide along at least a portion of the sidewalls. A second wet etch process removes the second carbon containing oxide and a fourth portions of the polymer. A third ash process forms a third carbon containing oxide along portions of the sidewalls and removes any remaining portions of the polymer.

1. Field
This disclosure relates generally to semiconductor processing, and more specifically, to a method for forming a through silicon via.
2. Related Art
Through silicon vias (TSV) with a high aspect ratio are typically formed using an etch-deposition-etch process sequence. The deposition step puts down a fluorocarbon polymer to protect the sidewall of the via opening and thus allows etching of the high aspect ratio via. One such process which uses this fluorocarbon polymer was developed by Bosch and may be referred to as the Bosch process. However, the Bosch process results in silicon-containing fluorocarbon polymer residual that is deposited on the sidewalls and bottom of the via opening. This polymer needs to be removed prior to the fill process in order to produce a reliable TSV.

Method for forming a through silicon via (TSV)


A size AA alkaline battery includes an anode principally composed of zinc functioning as an active material, a cathode principally composed of manganese dioxide or nickel oxyhydroxide functioning as an active material, a separator composed of a nonwoven fabric, an electrolyte composed of an aqueous solution of potassium hydroxide, and zinc oxide.

1. Field of the Invention
The present invention relates to a size AA alkaline battery in which discharge characteristics are improved and leakage of an electrolyte is suppressed.
2. Description of the Related Art
In recent years, trends toward miniaturization and portability of electronic devices have increased the number of commercially available alkaline battery-operated products. Potassium hydroxide solutions have been used as electrolytes in such alkaline batteries. Leakage of the electrolytes from the batteries to the exterior may disadvantageously cause damage to the electronic devices or human bodies. In particular, in a device in which four batteries are serially connected, when one battery among the four batteries is installed in reverse polarity, the electrolyte can easily leak from the battery to the exterior. There has been a need for improvement in such a case. For example, when one battery among the four batteries is installed in reverse polarity, Japanese Unexamined Patent Application Publication No. 5-135776 discloses a safety measure. That is, in each of a size D battery and a size C battery, a safety measure to prevent a current from flowing by providing a projection at an anode terminal is taken.


Ultrasonically formed seals, their use in semiconductor packages, and methods of fabricating semiconductor packages. A brittle center member (such as glass) has a molded edge member. That edge member is ultrasonically welded to a body. The molded edge member and body are comprised of ultrasonically weldable materials. A hermetically sealed semiconductor package includes a lid with a brittle center plate and a molded edge. The molded edge is ultrasonically welded to a body. Locating features that enable accurate positioning of the lid relative to the body, and energy directors can be included. Pins having a relieved portion and a protruding portion can also be hermetically sealed to the body. Such pins can have various lengths that enable stadium-type pin rows. The pins can be within channels, which can hold a sealant. The body can include a device that is electrically connected to the pins.

1. Field of the Invention
The present invention relates to packages and sealing techniques, and more particularly, to hermetic seals, hermetically sealed semiconductor packages, and hermetic sealing techniques.
2. Discussion of the Related Art
Semiconductor packages have proven useful in protecting integrated circuits and in attaching those circuits to electrical boards. More recently, such semiconductor packages have proven useful in protecting and mounting devices such as Micro-Electro Mechanical Systems (MEMS) assemblies and other imaging devices.
Semiconductor packages protect integrated circuits from harm caused by humidity, harmful gases, and various materials used in electronic assembly. Such protection usually takes the form of an airtight environmental seal, referred to herein as a hermetic seal. However, hermetic seals are used in many more applications than environmentally sealing semiconductor packages. Therefore, a hermetic seal as used herein refers to any environmental seal of any enclosed space.
Hermetically sealing semiconductor packages presents various challenges. For example, a semiconductor package might be subjected to a wide range of temperatures and thermal differentials, vibrations, accelerations, impacts, loads, and radiations. Compounding the sealing challenge is the relatively large number of individual hermetic seals that can be required. To understand this, consider that an integrated circuit (or another device) must be mounted in the package. Thus, a seal for an access port (usually a lid) is required. Further consider that an integrated circuit must electrically connect to an external circuitry, and that electrically conductive leads or pads, possibly a very large number of such leads or pads, must pass through the semiconductor package. Each of those leads or pads requires a hermetic seal. Another challenge is that in some applications, such as micro-mirror assemblies and UV erasable memories, light must pass through the semiconductor package. Still another challenge is hermetically sealing at high speed and at low cost.
Prior art semiconductor packages are generally comprised of a body having an embedded set of conductive leads and a cavity for holding a protected device. Electrical bonding wires electrically interconnect the conductive leads and the protected device. A lid is then placed over the cavity's access port. That lid is usually attached to the body using an adhesive such as an epoxy. Additionally, the locations where the conductive leads enter the body are usually sealed with a sealing compound, often an epoxy. The lid adhesive and sealing compound are typically applied using a liquid dispenser. Time, heat, and/or UV light is used to cure the dispensed liquid.
Examples of prior art semiconductor packages include Dual In-Line Packages (DIP), Plastic Pin Grid Array packages (PPGA), and Small Outline Integrated Circuit (SOIC) packages. For cost considerations, the body and lid are usually thermoplastic. However, ceramic semiconductor packages are sometimes used, particularly when light must pass through the semiconductor package. Then, a ceramic body and a ceramic lid having a transparent glass window are beneficial.
While generally successful, prior art semiconductor packages have certain problems. For example, bonding the lid to the body and sealing the conductive leads using a dispensed liquid are time consuming and can lead to contamination. Also, the required handling steps when applying the adhesive and/or sealing compound can lead to physical damage to the package or to the packaged device. Furthermore, many adhesives and sealants introduce moisture into the cavity, possibly leading to device corrosion and failure, or to hermetic seal cracks caused by thermally induced pressure during soldering or operation of the protected device. Indeed, any difference in the coefficients of thermal expansion of any of the parts can induce stresses and/or strains that can lead to hermetic seal failure.
Modern high-density integrated circuits (ICs) having a large number of connections place additional stresses on prior art hermetic seal techniques. For example, some integrated circuits require well over one hundred pins. Hermetically sealing such a large number of pins is difficult and time consuming as careful pin placement and alignment becomes increasingly critical and difficult, as does ensuring a reliable hermetic seal.
One prior art approach to hermetic sealing uses ultrasonic welding. Ultrasonic welding refers to welding using an intense, controlled vibration that develops friction-induced heating between elements. This heating, combined with pressure, causes melting of one or both of the welded elements at the interface between those elements. Upon solidification, a mechanical bond is created between the elements. According to the prior art, when ultrasonic welding is used with semiconductor packages, frictional heat is developed by placing a lid on a body, applying a predetermined pressure between the lid and the body, and then applying an intense ultrasonic vibration to the lid. The intense vibration is transmitted through the lid to induce a welding temperature. The induced temperature causes a flow of melted material that produces a semi-hermetic or hermetic seal between the lid and the body.
With prior art ultrasonic welding of semiconductor packages, a thermoplastic body and lid are preferred. Thermoplastic materials are common, inexpensive, and ultrasonically weld readily. Furthermore, thermoplastics are typically resilient, have only a relatively small amount of outgassing, and can have matching thermal coefficients of expansion.
While ultrasonic welding of semiconductor packages is useful, prior art ultrasonic welding techniques do not work well when attempting to hermetically seal brittle materials, such as ceramics and glass. Direct ultrasonic welding of those materials, even to a thermoplastic body, tends to induce cracks, breaks, and other damage to the brittle material.
Therefore, a new type of hermetic seal would be beneficial. Even more beneficial would be a new type of hermetic seal that is useful for hermetically sealing semiconductor packages. In particular, a new type of hermetic seal capable of sealing conductive pins to a body, and/or a lid to a body would be useful. Furthermore, a new hermetically sealed semiconductor package would also be beneficial. Also beneficial would be a new method of producing hermetic seals and a new way of assembling semiconductor packages.


The invention relates to interfaces acoutics wave components made of lithium tantalate. Two substrate make up the filter have the same cut and the same crystal orientation, the invention gives the best cut angles in particular for optimizing the electromechanical coupling coefficient that determines the final performance characteristics of the component produced. Curves giving the variations of the coupling coefficient an the attenuation as a function of the cut angles and of the direction of propagation are provided. The values of the main acoustic characteristics of the component for these optimum cut angles are also given. The application of this type of device are, on the on hand, uses as a passive component such a resonator or a filter or a delay line, or as an integrated device, either in a measurement chain or in any array of devices operating according to the principle of recognition of the device by a phase code.

It is known to produce surface acoustic wave devices that use the propagation of waves on the surface of a piezoelectric substrate. In the case of what are called Rayleigh waves, these are generated and received by interdigitated comb transducers composed of interlaced electrodes between which a potential difference is imposed. These devices have two main drawbacks.
Firstly, in order for the surface waves to propagate correctly on the surface of the substrate, this surface must remain free. This condition is obtained by encapsulation technologies for obtaining a cavity.
Secondly, the pitch of the electrodes making up the interdigitated combs is often small, of the order of a few hundred nanometers. In addition, conducting particles of very small dimensions present inside the package may short-circuit a transducer and disturb the normal operation of the device. To alleviate this drawback, it is necessary either to make the packages for the components hermetically sealed, or to deposit a thin layer of insulating dielectric material on the transducers. This operation, called passivation, makes it possible to eliminate sensitivity to conducting particles. However, passivation does not make it possible to dispense with the encapsulation operation, which is an operation expensive to carry out.
The use of interface acoustic wave devices allows the various problems associated with encapsulation to be solved. In this case, use is no longer made of the propagation of the acoustic waves on the surface of the substrate, but at the interface between two substrates instead. Of course, this device makes it possible to obtain a passivated component no longer requiring a cavity to be produced. Moreover, the package may be completely eliminated.
In 1924, Stoneley demonstrated the possibility of guiding an acoustic wave at the interface between two materials [Proc. Roy. Soc. London A 106, 416]. These waves were regarded as being polarized in the sagittal plane.
In 1971, Maerfeld and Tournois demonstrated the existence of horizontal shear waves propagating at the surface between two materials. The piezoelectric case was considered [C. Maerfeld and P. Tournois, Appl. Phys. Lett. 19, 117, 1971]. The first use of this type of wave for acoustic components is disclosed in patent FR 2 145 750. The invention described uses the propagation of pure shear waves at the interface between two materials, at least one of which is piezoelectric. The case in which the two materials are identical is considered. However, the above patent makes no mention of transducers placed at the interface between the two materials.
In 1983, the propagation of waves at the interface between a piezoelectric material and an isotropic material, for the purpose of producing packageless SAW (surface acoustic wave) devices is described, which implicitly assumes that the transducers are placed at the interface. The coupling coefficient was also studied [Shimitzu et al., "Stoneley waves propagating along an interface between piezoelectric material and isotropic material", 1983 IEEE U.S. Proc. pp 373–375].
More recently, in 1998, a different combination of materials was examined for the purpose of filtering [M. Yamaguchi, T. Yamashita, K. Hashimoto and T. Omori, "Highly piezoelectric waves in Si/SiO2/LiNbO3 and Si/SiO2/LiNbO3 structures" (unpublished)].
Finally, in 1999, patent FR 2 799 906 describes filters using transducers at the interface between two identical piezoelectric materials.
In general, an interface acoustic wave device consists of two substrates denoted by S1 and S2, at least one of which is piezoelectric, and of an interface region I lying between these two substrates, as indicated in FIG. 1. In the general case, the interface region I is a structure that comprises at least the electro-acoustic transducers E. Electrical interconnections coupled to said devices allow signals to be emitted and transmitted.
The interface waves can be used to produce passive components. In general, any type of device obtained using waves propagating on the surface of a crystal can be produced using interface waves. In particular, it is possible to reflect the interface waves using arrays of metal electrodes with a period equal to a half-wavelength placed at the interface. Thus, firstly a resonator is produced, by placing an interdigitated transducer between two reflector arrays, and secondly a filter, by coupling resonators together via electrical or acoustic means. The directivity of a transducer is improved by interspersing reflectors therein. All applications of surface wave components are therefore accessible, especially delay lines, band filters, resonators and dispersive filters. Applications of these components as measurement sensors are also possible.
Phase code devices have specific transducers characterized by a distribution of the electrodes such that it is known how to associate one particular code with a given phase code component. Remotely interrogable devices using radio waves employ this principle. The operation is as follows: a phase code is used at emission of the wave, and the wave is picked up by an antenna connected to the input of the phase-code component; conventionally, the transducer converts the signal into a mechanical wave. Said wave propagates as far as the output transducer where it is then reconverted into an electrical signal and re-emitted. The received signal is analyzed and the component that has received and transformed the signal is thus identified.
Interface wave devices can be used as remotely interrogable devices, especially for measurement applications, such as for the measurement of pressure, temperature or acceleration.
The choice of structures for the interface wave components may vary very greatly. In particular, the following combinations may be mentioned:                the substrate S1 is piezoelectric and S2 is not. In this case, S2 is chosen according to its mechanical properties so as to make it easier to produce the components. For example, if S1 is made of lithium niobate or lithium tantalate, S2 will preferably be made of fused silica or single-crystal silicon;        the two substrates are both piezoelectric, but of different nature. For example, the following combinations may be mentioned:                    quartz/lithium niobate            quartz/lithium tantalate            lithium tantalate/lithium niobate;                        the two substrates are of the same nature but of different crystal cut. FIG. 2 shows, using the IEEE 1949 conventions in the initial orthonormal coordinate system (X,Y,Z), Z being parallel to the optical axis of the crystal, X being defined by the piezoelectricity of the crystal and Y being perpendicular to (X,Z), the geometrical representation of the cut plane being defined by two successive rotation angles φ and θ. Here, φ corresponds to a first rotation about the Z axis, the coordinate system obtained thus being denoted by (X′,Y′,Z′) with Z′ coincident with Z, and θ corresponds to a second rotation about the X′ axis, the coordinate system obtained thus being denoted by (X″,Y″,Z″), with Z′ coincident with X′. In this final coordinate system, the direction of propagation of the acoustic waves is then defined by a third angle ψ representing a rotation about the Y″ axis. As an example, with these conventions, the values of the angles for the cuts normally used in surface waves for ST quartz are the following:                    φ=0°; θ=42.75°; ψ=0°; and finally                        the two substrates may be of the same nature and same cut. For example, it is possible to use quartz and lithium niobate or lithium tantalate. In this case, as a general rule the assembly operation will be carried out with the same crystal orientation of the two substrates.
The latter case is particularly interesting in so far as the problems of compatibility between the substrates S1 and S2, in particular the thermal expansion and assembly problems, are implicitly solved. In this case, the orientations of the crystal faces are chosen so as to obtain polarizations of the same direction.
Four major characteristics define the acoustic wave propagation properties of piezoelectric materials. These are:                the velocity V of propagation of the interface acoustic wave. This parameter is important in so far as, for a given operating frequency F, it determines the pitch P of the array of teeth of the electrode combs which is proportional to V/F. When one works at high frequency, typically of the order of a few GHz, achieving high velocities makes it possible to maintain sufficiently wide pitches compatible with current etching technologies;        the attenuation A or insertion loss, expressed in dB per acoustic wavelength, a parameter that it is desired, in general, to reduce so as to reduce the insertion losses of the device;        the first-order coefficient CFT of the variation in frequency as a function of temperature near the ambient temperature, expressed in ppm.C−1. The configuration of the device will be less sensitive to thermal variations the lower this coefficient; and        the electromechanical coupling coefficient k2 representative of the maximum relative frequency band that can be obtained with a device, this coefficient being calculated as the relative half-difference between the velocities of the surface waves on the free substrate and the metalized substrate. In general, this coefficient is the parameter that it is desired to maximize, k2 being a dimensionless parameter expressed as a percent.
These various parameters, and in particular the coupling coefficient k2, depend strongly on the cut angle of the piezoelectric crystal and on the direction of propagation. It is thus possible to obtain, depending on the cut angle in the case of lithium tantalate, k2 values varying between 0 and 7 as indicated in FIGS. 3a and 3b. FIG. 3a shows the variation of k as a function of (φ,ψ) at zero θ and FIG. 3b shows the variation of k2 as a function of (θ,ψ) at zero φ. In these figures, the discontinuities show the regions within which no possible propagation mode exists. The choice of the cut angle is therefore fundamental. However, the variations in the acoustic characteristics as a function of this angle cannot be determined simply, for example by considerations regarding the crystal structure. They are also very different from those that are obtained in the case of free materials used for the surface acoustic waves.
U.S. Pat. No. 2,799,906 (Pierre Tournois) relating to the production of interface acoustic wave filters gives general recommendations mentioned by way of example and allowing optimum cut angles to be chosen. Particularly mentioned in the case of the use of lithium tantalate that the cuts may be taken along the Y crystallographic axis (where Y is rotated through a certain angle, for example 175°).

Interface acoustic wave device made of lithium tantalate


A chair system according to embodiments of the present invention includes a base comprising a seat for a user and one or more support legs, a back, and a flexible back support element rigidly coupled to the back and to the base, the flexible back support element comprising a flex zone, the flex zone comprising one or more notches, wherein the back is reclinable from an upright position to a reclined position, wherein the one or more notches are configured to narrow as the back reclines from the upright position to the reclined position, and wherein the one or more notches are open in the upright position and closed in the reclined position.

Existing chairs with reclining backs often employ complex mechanisms to accommodate reclining motion, and such complex mechanisms are often expensive to manufacture. Chairs with plastic or polymer reclining backs often wear out rapidly at the point of primary bending, are often too stiff or too flimsy throughout reclining, and often their reclining resistance typically does not vary throughout reclining.

This patent is subject to a terminal disclaimer.

Flexible back support member with integrated recline stop notches


A fusion splicing apparatus includes discharge electrodes 13 and 15 to discharge-heat and fusion-splice end faces 5a and 7a of optical fibers 1 and 3, fiber holders 17 and 19 to hold the optical fibers 1 and 3, V-groove blocks 21 and 23 to receive, position, and fix parts of the optical fibers 1 and 3 on the end face sides of the fiber holders 17 and 19, V-groove-block moving mechanisms 33 and 35 to move the V-groove blocks 21 and 23 so as to shift an axial center of the optical fibers 1 and 3 from a straight line between the discharge electrodes 13 and 15, and holder moving mechanisms 37 and 39 to move the fiber holders 17 and 19 so as to shift the axial center of the optical fibers 1 and 3 from the straight line between the discharge electrodes 13 and 15.

Generally, fusion-splicing end faces of a pair of optical fibers to each other by discharge heating is carried out by holding the pair of optical fibers with holding units and by placing, positioning, and fixing parts of the optical fibers on the end-face sides of the holding units into V-grooves formed in V-groove blocks.
At this time, a virtual straight line joining a pair of discharge electrodes to each other and an axial center of the optical fibers are usually set to agree with each other. In this case, the holding units and V-groove blocks hold and fix the pair of optical fibers so that the axial center of the optical fibers agrees with the straight line that joins the pair of discharge electrodes to each other.
If the optical fibers have a low melting point, the fusion splicing thereof must avoid excessive fusion. This raises a necessity of slightly shifting the axial center of the pair of optical fibers from the virtual straight line that joins the pair of discharge electrodes to each other. To fulfill the necessity, only the V-groove blocks that are located in the vicinities of the splicing end faces of the optical fibers may be moved.
A known technique of shifting an axial center of optical fibers from a virtual straight line joining a pair of discharge electrodes and fusion-splicing the optical fibers is described in Japanese Patent Publication No. 2860831 (Patent Literature 1). A known technique of moving a V-groove block is described in Japanese Unexamined Patent Application Publication No. 2002-6167 (Patent Literature 2).

Fusion splicing apparatus and method thereof


A method is provided for determining faults during the operation of a pump unit. At least two electric variables that determine the electric output of the motor and at least one fluctuating hydraulic variable of the pump are detected. The detected values or values formed from these variables by algorithms are automatically compared to predefined stored values using electronic data processing and the results of this comparison are used to determine whether or not faults have occurred.

In the meanwhile, it is counted as belonging to the state of the art to provide a multitude of sensor systems with pump assemblies, on the one hand to detect operating conditions, and on the other hand to also determine faulty conditions of the installation and/or of the pump assembly. With this, it is disadvantageous that the sensor system required with regard to this, is not only complicated and expensive, but is often also susceptible to faults.
Against this background, it is the object of the invention, to provide a method for determining faults on operation of a pump assembly which may be carried out with as little as possible sensor technology, as well as a device for carrying out the method.

Method for determining faults during the operation of a pump unit