A system and method are provided for improving stack integrity for image receiving media substrates in a compiler tray in an image forming device by supplementing the structure of the compiler tray with a pair of auger components configured with a bottom surface that, in conjunction with a stepped support structure in the compiler tray, applies a mechanical leveling force to reduce or otherwise eliminate detrimental effects associated with substrate curl or uneven set build-up in the compiler tray. The vertical compiler components provide an accommodation for localized thickness build-up in compiled image receiving media substrates by one or more processing or post-processing steps. The auger components provide a mechanical pressing force that is intended to level a top surface of the compiled substrates with the configuration of the compiler tray providing the relief area necessary for the accommodation.

1. Field of Disclosed Subject Matter
This disclosure relates to systems and methods for improving stack integrity for image receiving media substrates in a compiler tray in an image forming device by supplementing the structure of the compiler tray with a pair of auger components configured with a bottom surface that, in conjunction with a stepped support structure in the compiler tray, applies a mechanical leveling force to reduce or otherwise eliminate detrimental effects associated with substrate curl or uneven set build-up in the compiler tray.
2. Related Art
Many modern image forming devices are comprised of myriad discrete component sub-systems. These discrete component sub-systems include (1) image receiving media supply components at an input end of the image forming device, (2) pre-processing and/or conditioning components for preparing surfaces of the image receiving media substrates to receive marking material to form images, (3) a marking material delivery component for depositing marking material on the surfaces of the image receiving media substrates to form the images according to input or read image signals, (4) fusing/finishing components for fixing the deposited marking material on the image receiving media substrates, and (5) post-processing devices for carrying out certain post processing tasks including compilers for collating the image receiving media substrates as sets comprising multi-page finished documents, for example, for stapling or otherwise binding the multi-page finished documents.
The individual component sub-systems are generally interconnected by a series of increasingly intricate image receiving media substrate transport sub-systems, paths and/or components. The image receiving media transport sub-systems, paths and/or components are generally designed and implemented in particular office-sized image forming devices in a manner that manages a size footprint for the image forming devices while not specifically limiting the transport requirements from an output of one component sub-system to an input of another component sub-system.
At an end of the processing scheme, the form and function of the image receiving media transport sub-systems, paths and/or components often become somewhat more narrowly defined. The print job is generally completed with individual sheets of image receiving media substrates, with the images formed and fixed thereon, being collected in sets according to instructions for completing individual print jobs. Individual image receiving media substrates and/or compiled sets of image receiving media substrates are collected and/or assembled in differing configurations of compiler trays associated with one or more of the post-processing sub-systems. Manipulation of the individual image receiving media substrates, or of the sets of image receiving media substrates, at that point in the processing of the documents responsive to the directed print job can be particularly intricate. There is often a need to ensure that the sets of image receiving media substrates are fairly precisely handled, stacked, and/or registered in order to facilitate one or more post-processing or finishing processes including, for example, stapling or binding.
The manipulations associated with aligning (registering) individual sheets into sets are broadly referred to as, and are generally understood by those of skill in the art to involve, functions of stacking and tamping the individual sheets of image receiving media substrates into precise alignment in the sets. Stacking often occurs against a static edge alignment body portion at an output of the processing or post-processing devices to provide longitudinal alignment of the individual sheets of image receiving media substrates with respect to a process direction, stacking being generally considered to be a passive process. Tamping generally refers to a most often active alignment component in which paddles or other devices may be employed on any, but most often, lateral sides of a set of image receiving media substrates to align the set in a direction orthogonal to the process direction.
Certain currently-fielded systems may be configured with what may generally be described as vertical compiler sub-systems. FIG. 1 illustrates a simple schematic representation of a side view of an exemplary system 100 incorporating a commonly-implemented vertical compiler. FIG. 2 illustrates a simple schematic representation of a top plan view of an exemplary system 100 incorporating the same commonly-implemented vertical compile shown in FIG. 1. As shown in FIGS. 1 and 2, individual sheets of image receiving media substrates 130 exit an imaging system processing/post-processing device 110 at an exit/ejection port 115 and are individually deposited in an output (compiler) tray 120.
A "bottom" or platform of the output (compiler) tray 120 may consist of a plurality of longitudinally-arranged image receiving media substrate supports that extend in the process (longitudinal) direction of the image receiving media substrates 130. The image receiving media substrates 130 rest on the substrate supports and are generally manually recoverable from the substrate supports.
In exemplary systems such as that shown in FIGS. 1 and 2, vertical set compiling may occur in one or more stages as follows. Individual image receiving medium substrates 130 may be dropped in stages from the output (compiler) tray 120, acting as a temporary compiler. This dropping may be effected, by laterally-opposing motions, i.e., orthogonal to the process direction, of the plurality of longitudinal image receiving media substrate supports (or arms) toward opposed lateral edges of the output (compiler) tray 120, displacing the substrate supports from under the image receiving media substrates 130. As a result of the linear movement of the plurality of longitudinal image receiving media substrate supports, each of the image receiving media substrates 130 drops down to an image receiving medium set receiving platform, or an output set collection platform component 150.
The image receiving media substrates 130 may be collected as a set 140 on the output set collection platform component 150. The output set collection platform component 150 may, in turn, be comprised of at least a pair of compiler shutters 152/154. Each sheet of the image receiving media substrates 130 in the set is dropped in a similar fashion to create the set 140 of image receiving media substrates on the compiler shutters 152/154. When the set 140 of image receiving media substrates is complete and properly registered, and optionally, for example, bound or stapled, the set 140 of image receiving media substrates is then dropped onto a stack of previously-dropped sets 170 of image receiving media substrates, or directly onto some manner of set output transport path 160 to be moved in a process direction B from a first stack position to a second stack position 180 and beyond.
The above-described dropping function is currently undertaken in commonly-implemented vertical compiler sub-systems by rapid cycling of the compiler shutters 152/154 in opening and then closing in mechanically opposing motions.

Systems and methods for implementing a unique variable stacking surface for set compiling in image forming devices


An imaging device ICD, which realizes an image blurring compensation function which achieves image blurring compensation during a framing period and image blurring compensation during releasing, is provided. In the imaging device (ICD), an OIS unit control section (104) compensates image blurring occurring in an optical image by moving an optical axis of an imaging optical system (100), and compensates the image blurring by changing a position of cutout of image data outputted from an image sensor (106). An image shift amount calculation section (39x, 39y) detects image blurring information. A system controller (120) causes the OIS unit control section (104) to mainly move the optical axis during an exposure period based on the detected image blurring information, and to mainly change the position of the cutout of the image data during a period other than the exposure period, thereby compensating image blurring which occurs in a taken image.

Recently, downsizing and weight saving of devices have been developed while imaging devices such as a digital still camera, a video movie, and the like have been popularized. Further, a demand for image blurring compensation has been increased in accordance with enhancement of an image quality of the imaging device.
An imaging device (Patent Document 1) having conventionally known image blurring compensation means includes vibration detection means which detects vibration of a camera due to image blurring, arithmetic means which calculates an appropriate compensation amount for the image blurring, an image blurring compensation lens, lens drive means which drives the image blurring compensation lens, and compensation mode selection means for selecting one of a constant compensation mode and a release compensation mode in which blurring compensation is performed only during releasing. In the imaging device, when the constant compensation mode is selected, compensation by the lens drive means is started after start of vibration detection operation by the vibration detection means. When the release compensation mode is selected by the compensation mode selection means, compensation by the lens drive means is performed only during releasing.
In the above imaging device, the constant compensation mode in which image blurring compensation is constantly performed after a release button is pressed halfway, and the release compensation mode in which image blurring compensation is performed only during releasing are provided as modes of image blurring compensation. Thus, it is intended that in the case where a state of the release button being pressed halfway continues for a prolonged period of time, the release compensation mode is selected to reduce useless consumption of a battery which is consumed by a motor, and the like, and in the case where an effect of the image blurring compensation is desired to be confirmed beforehand, the constant compensation mode is selected to confirm the effect of the image blurring compensation.
Also, it is intended that when the release compensation mode is selected, a moveable amount of a compensation optical system between a center position at which an optical axis is located and a limit position is ensured by setting the compensation optical system at the center position, whereby a function of the image blurring compensation of the release compensation mode can be effectively used.
[Patent Document 1] Japanese Laid-Open Patent Publication No. 5-224270


The present invention provides a spread illuminating apparatus in which a transparent substrate is illuminated thereby illuminating a liquid crystal panel provided close to the transparent substrate in order to enhance the illumination luminance and also suppress the interference fringes. In a spread illuminating apparatus in which a square transparent substrate is provided close to the surface of a liquid crystal panel, and a fluorescent tube as a bar-like light source is arranged on the side surface of the transparent substrate, a plurality of straight groove portions are formed on the surface of the transparent substrate intersecting one another obliquely with respect to the four sides of the transparent substrate. While the convergence of the rays of light is carried out only for the component thereof vertical to the groove portions, in the present invention, since the groove portions are formed in such a manner as to intersect one another, the rays of light which are emitted in different directions are all converged, whereby the luminance is remarkably enhanced. In addition, the groove portions intersecting one another suppress the interference fringes of the rays of light.

1. Field of the Invention
The present invention relates to a spread illuminating apparatus for use in a display portion of a personal computer, a word processor or the like (hereinafter, they are referred to as "a personal computer"), or a mobile apparatus, a portable telephone or the like.
2. Description of the Related Art
As for display devices for use in personal computers, heretofore, cathode ray tubes (so-called picture tubes) have been mainly used. However, since these cathode ray tubes are large and heavy and in addition thereto have large power consumption, recently, liquid crystal panels have been employed in many cases. Therefore, the liquid crystal panels each having a large number of pixels have been developed and other circuit elements have been miniaturized, leading to that small personal computers such as a note-book type or the like have rapidly come into wide use. The liquid crystal panels have been often employed as the display devices for use in the mobile equipments, the portable phones or other various electronic equipments in addition to the above-mentioned personal computers.
While the demand for the liquid crystal panels has drastically increased as described above, a suitable illuminating apparatus is required, because the liquid crystal panel itself does not emit the rays of light. Conventionally, in a display device having a relatively large area as in a personal computer, for example, the cold cathode fluorescent lamps (CCF) or the hot cathode fluorescent lamps (HCFL) have been used as the illuminating apparatuses therefor. As for the concrete construction thereof, a square transparent substrate is provided in close proximity to the surface of a liquid crystal panel, the transparent substrate is illuminated by a fluorescent tube which is provided parallel to the side surface of the transparent substrate, and then the rays of light which are emitted from the fluorescent tube are introduced to the liquid crystal panel which is in turn illuminated with the rays of light introduced thereto.
Since the discharge of electricity is caused between the opposite electrodes in the fluorescent tube, a high voltage for the discharge of electricity is required. For this reason, an oscillation circuit employing a semiconductor device is provided to supply the voltage which is generated on the basis of the oscillation to the fluorescent tube.
Because the personal computer is constructed by combining the electric circuits and the electric apparatuses, the personal computer itself consumes the electric power. Thus, the study for power saving has been made and as a result, currently, the personal computers with remarkably reduced power consumption as compared with the conventional ones have come into wide use. In particular, this tendency is remarkable for the portable personal computers called the note-book type. However, if the amount of power consumption of the illuminating apparatus is large, then the greater part of the electric power generated by the batteries will be consumed in the illuminating apparatus.
On account of this, an illuminating apparatus that employs a white light emitting diode instead of the fluorescent tube has been developed. The patent application of this illuminating apparatus has already been filed with the Patent Office by the present inventors (refer to Japanese Patent Laid-open Publication No. Hei 10-182076). This illuminating apparatus is structured such that a transparent substrate is placed on a liquid crystal panel, a bar-like light conductive member which is made of a transparent material and a part of which is provided with an optical path conversion means is arranged on the end of the transparent substrate, and a light emitting diode is placed on the end portion of the light conductive member in order to emit the rays of light. The rays of light which have been emitted from the light emitting diode are guided from the end portion of the light conductive member into the light conductive member and then the direction of the emitted rays of light is changed by the optical path conversion means so that the rays of light directly enter the transparent substrate.
Now, whether the bar-like light source is comprised of the fluorescent tube or the combination of the light conductive member and the light emitting diode, it is impossible to brightly illuminate the liquid crystal panel which is arranged in contact with the lower surface of the transparent substrate unless the transparent substrate is uniformly illuminated. Therefore, various ideas have been proposed so far.
Now, an example of a conventional spread illuminating apparatus will be hereinbelow described with reference to FIG. 8 which is an exploded view of the conventional spread illuminating apparatus and FIG. 9 which is a perspective view showing the assembled state thereof. A liquid crystal panel 1 is a reflection type liquid crystal device and has on its surface liquid crystal cells 1a as pixels disposed in a mosaic arrangement. A square transparent substrate 2 is provided close to the upper surface of the liquid crystal panel 1, and a fluorescent tube 3 as a bar-like light source is provided parallel with the side surface of the transparent substrate 2.
In this construction, when the fluorescent tube 3 is lit, the rays of light which have been emitted from the fluorescent tube 3 enter the transparent substrate 2 to illuminate the liquid crystal panel 1 through the transparent substrate 2. In order that the rays of light emitted from the fluorescent tube 3 may be effectively directed toward the transparent substrate 2, a reflection plate 4 is provided behind the fluorescent tube 3.
A large number of groove portions 2a each having a substantial triangle in cross section are provided on the surface of the transparent substrate 2 in such a way as to be parallel with the fluorescent tube 3. Each of the portions which are defined between the adjacent groove portions 2a forms a plane portion 2b. In order to realize the uniformity of the surface light emission, the gaps between the groove portions 2a are large in the vicinity of the fluorescent tube 3 and become smaller as the distance from the fluorescent tube 3 increases. In addition, the groove portions 2a are shallow in the vicinity of the fluorescent tube 3 and become deeper as the distance from the fluorescent tube 3 increases.
In this connection, when the fluorescent tube 3 emits the rays of light, the rays of light thus emitted therefrom enter the transparent substrate 2 at the side surface thereof and strike against the groove portions 2a to be directed toward the liquid crystal panel 1. However, only the components of the rays of light vertical to the groove portions 2a undergo optical path conversion. Therefore, in FIG. 9, only the components of the rays of light in the direction A are converged, while the components of the rays of light in the direction B parallel with the groove portions 2a are not converged at all. As a result, as shown in FIG. 7, the distribution in the direction B is widely spread. Note that, the rays of light which are directed from the transparent substrate 2 toward the liquid crystal panel 1 are reflected by the liquid crystal panel 1, thereby entering the transparent substrate 2 again to be emitted in the viewing direction.
When the illuminating apparatus for the liquid crystal display device is used in the portable information equipment such as a portable phone, a wide view angle is not required assuming that it is for personal use. The fact is that the rays of light emitted in a wide direction turn out to be useless. Therefore, the useless rays of light emitted in the direction B are converged, whereby it is possible to enhance the front viewing luminance. In order to converge the rays of light emitted in the direction B, additional groove portions need to be formed in the direction perpendicular to the direction of the formation of the existing groove portions. However if the groove portions are formed substantially in parallel with the travelling direction of the rays of light, it is still impossible to converge the rays of light.
If the transparent substrate 2 is provided on the upper surface of the liquid crystal panel 1 as in the above structure, then interference fringes called the Moiré fringes may be generated on the viewing face of the liquid crystal panel 1 in some cases. When the Moiré fringes are generated, the liquid crystal panel 1 becomes hard to view. It has been discovered that the generation of the Moiré fringes has a close relation with the depth, size and gap of the groove portion 2a of the transparent substrate 2. In addition thereto, it has also been known that the Moiré fringes are generated most intensely when the groove portions 2a are substantially parallel with the direction in which the liquid crystal cells 1a of the liquid crystal panel 1 are arranged.

Spread illuminating apparatus with transparent substrate having groove portions obliquely arranged and intersecting one another


Feedback cancellation apparatus uses a cascade of two filters along with a short bulk delay. The first filter is adapted when the hearing aid is turned on in the ear. This filter adapts quickly using a white noise probe signal, and then the filter coefficients are frozen. The first filter models parts of the hearing-aid feedback path that are essentially constant over the course of the day. The second filter adapts while the hearing aid is in use and does not use a separate probe signal. This filter provides a rapid correction to the feedback path model when the hearing aid goes unstable, and more slowly tracks perturbations in the feedback path that occur in daily use. The delay shifts the filter response to make the most effective use of the limited number of filter coefficients.

The present invention relates to improved apparatus and methods for canceling feedback in audio systems such as hearing aids.
Mechanical and acoustic feedback limits the maximum gain that can be achieved in most hearing aids (Lybarger, S. F., xe2x80x9cAcoustic feedback controlxe2x80x9d, The Vanderbilt Hearing-Aid Report, Studebaker and Bess, Eds., Upper Darby, Pa.: Monographs in Contemporary Audiology, pp 87-90, 1982). System instability caused by feedback is sometimes audible as a continuous high-frequency tone or whistle emanating from the hearing aid. Mechanical vibrations from the receiver in a high-power hearing aid can be reduced by combining the outputs of two receivers mounted back-to-back so as to cancel the net mechanical moment; as much as 10 dB additional gain can be achieved before the onset of oscillation when this is done. But in most instruments, venting the BTE earmold or ITE shell establishes an acoustic feedback path that limits the maximum possible gain to less than 40 dB for a small vent and even less for large vents (Kates, J. M., xe2x80x9cA computer simulation of hearing aid response and the effects of ear canal sizexe2x80x9d, J. Acoust. Soc. Am., Vol. 83, pp 1952-1963, 1988). The acoustic feedback path includes the effects of the hearing-aid amplifier, receiver, and microphone as well as the vent acoustics.
The traditional procedure for increasing the stability of a hearing aid is to reduce the gain at high frequencies (Ammitzboll, K., xe2x80x9cResonant peak controlxe2x80x9d, U.S. Pat. No. 4,689,818, 1987). Controlling feedback by modifying the system frequency response, however, means that the desired high-frequency response of the instrument must be sacrificed in order to maintain stability. Phase shifters and notch filters have also been tried (Egolf, D. P., xe2x80x9cReview of the acoustic feedback literature from a control theory point of viewxe2x80x9d, The Vanderbilt Hearing-Aid Report, Studebaker and Bess, Eds., Upper Darby, Pa.: Monographs in Contemporary Audiology, pp 94-103, 1982), but have not proven to be very effective.
A more effective technique is feedback cancellation, in which the feedback signal is estimated and subtracted from the microphone signal. Computer simulations and prototype digital systems indicate that increases in gain of between 6 and 17 dB can be achieved in an adaptive system before the onset of oscillation, and no loss of high-frequency response is observed (Bustamante, D. K., Worrell, T. L., and Williamson, M. J., xe2x80x9cMeasurement of adaptive suppression of acoustic feedback in hearing aidsxe2x80x9d, Proc. 1989 Int. Conf. Acoust. Speech and Sig. Proc., Glasgow, pp 2017-2020, 1989; Engebretson, A. M., O""Connell, M. P., and Gong, F., xe2x80x9cAn adaptive feedback equalization algorithm for the CID digital hearing aidxe2x80x9d, Proc. 12th Annual Int. Conf. of the IEEE Eng. in Medicine and Biology Soc., Part 5, Philadelphia, Pa., pp 2286-2287, 1990; Kates, J. M., xe2x80x9cFeedback cancellation in hearing aids: Results from a computer simulationxe2x80x9d, IEEE Trans. Sig. Proc., Vol.39, pp 553-562, 1991; Dyrlund, O., and Bisgaard, N., xe2x80x9cAcoustic feedback margin improvements in hearing instruments using a prototype DFS (digital feedback suppression) systemxe2x80x9d, Scand. Audiol., Vol. 20, pp 49-53, 1991; Engebretson, A. M., and French-St. George, M., xe2x80x9cProperties of an adaptive feedback equalization algorithmxe2x80x9d, J. Rehab. Res. and Devel., Vol. 30, pp 8-16, 1993; Engebretson, A. M., O""Connell, M. P., and Zheng, B., xe2x80x9cElectronic filters, hearing aids, and methodsxe2x80x9d, U.S. Pat. No. 5,016,280; Williamson, M. J., and Bustamante, D. K., xe2x80x9cFeedback suppression in digital signal processing hearing aids,xe2x80x9d U.S. Pat. No. 5,019,952).
In laboratory tests of a wearable digital hearing aid (French-St. George, M., Wood, D. J., and Engebretson, A. M., xe2x80x9cBehavioral assessment of adaptive feedback cancellation in a digital hearing aidxe2x80x9d, J. Rehab. Res. and Devel., Vol. 30, pp 17-25, 1993), a group of hearing-impaired subjects used an additional 4 dB of gain when adaptive feedback cancellation was engaged and showed significantly better speech recognition in quiet and in a background of speech babble. Field trials of a feedback-cancellation system built into a BTE hearing aid have shown increases of 8-10 dB in the gain used by severely-impaired subjects (Bisgaard, N., xe2x80x9cDigital feedback suppression: Clinical experiences with profoundly hearing impairedxe2x80x9d, In Recent Developments in Hearing Instrument Technology: 15th Danavox Symposium, Ed. by J. Beilin and G. R. Jensen, Kolding, Denmark, pp 370-384, 1993) and increases of 10-13 dB in the gain margin measured in real ears (Dyrlund, O., Henningsen, L. B., Bisgaard, N., and Jensen, J. H., xe2x80x9cDigital feedback suppression (DFS): Characterization of feedback-margin improvements in a DFS hearing instrumentxe2x80x9d, Scand. Audiol., Vol. 23, pp 135-138, 1994).
In some systems, the characteristics of the feedback path are estimated using a noise sequence continuously injected at a low level (Engebretson and French-St.George, 1993; Bisgaard, 1993, referenced above). The weight update of the adaptive filter also proceeds on a continuous basis, generally using the LMS algorithm (Widrow, B., McCool, J. M., Larimore, M. G., and Johnson, C. R., Jr., xe2x80x9cStationary and nonstationary learning characteristics of the LMS adaptive filterxe2x80x9d, Proc. IEEE, Vol. 64, pp 1151-1162, 1976). This approach results in a reduced SNR for the user due to the presence of the injected probe noise. In addition, the ability of the system to cancel the feedback may be reduced due to the presence of speech or ambient noise at the microphone input (Kates, 1991, referenced above; Maxwell, J. A., and Zurek, P. M., xe2x80x9cReducing acoustic feedback in hearing aidsxe2x80x9d, IEEE Trans. Speech and Audio Proc., Vol. 3, pp 304-313, 1995). Better estimation of the feedback path will occur if the hearing-aid processing is turned off during the adaptation so that the instrument is operating in an open-loop rather than closed-loop mode while adaptation occurs (Kates, 1991). Furthermore, for a short noise burst used as the probe in an open-loop system, solving the Wiener-Hopf equation (Makhoul, J. xe2x80x9cLinear prediction: A tutorial review,xe2x80x9d Proc. IEEE, Vol. 63, pp 561-580, 1975) for the optimum filter weights can result in greater feedback cancellation than found for LMS adaptation (Kates, 1991). For stationary conditions up to 7 dB of additional feedback cancellation is observed solving the Wiener-Hopf equation as compared to a continuously-adapting system, but this approach can have difficulty in tracking a changing acoustic environment because the weights are adapted only when a decision algorithm ascertains the need and the bursts of injected noise can be annoying (Maxwell and Zurek, 1995, referenced above).
A simpler approach is to use a fixed approximation to the feedback path instead of an adaptive filter. Levitt, H., Dugot, R. S., and Kopper, K. W., xe2x80x9cProgrammable digital hearing aid systemxe2x80x9d, U.S. Pat. No. 4,731,850, 1988, proposed setting the feedback cancellation filter response when the hearing aid was fitted to the user. Woodruff, B. D., and Preves, D. A., xe2x80x9cFixed filter implementation of feedback cancellation for in-the-ear hearing aidsxe2x80x9d, Proc. 1995 IEEE ASSP Workshop on Applications of Signal Processing to Audio and Acoustics, New Paltz, N.Y., paper 1.5, 1995, found that a feedback cancellation filter constructed from the average of the responses of 13 ears gave an improvement of 6-8 dB in maximum stable gain for an ITE instrument, while the optimum filter for each ear gave 9-11 dB improvement.
A need remains in the art for apparatus and methods to eliminate xe2x80x9cwhistlingxe2x80x9d due to feedback in unstable hearing-aids.
The primary objective of the feedback cancellation processing of the present invention is to eliminate xe2x80x9cwhistlingxe2x80x9d due to feedback in an unstable hearing-aid amplification system. The processing should provide an additional 10 dB of allowable gain in comparison with a system not having feedback cancellation. The presence of feedback cancellation should not introduce any artifacts in the hearing-aid output, and it should not require any special understanding on the part of the user to operate the system.
The feedback cancellation of the present invention uses a cascade of two adaptive filters along with a short bulk delay. The first filter is adapted when the hearing aid is turned on in the ear. This filter adapts quickly using a white noise probe signal, and then the filter coefficients are frozen. The first filter models those parts of the hearing-aid feedback path that are assumed to be essentially constant while the hearing aid is in use, such as the microphone, amplifier, and receiver resonances, and the basic acoustic feedback path.
The second filter adapts while the hearing aid is in use and does not use a separate probe signal. This filter provides a rapid correction to the feedback path model when the hearing aid goes unstable, and more slowly tracks perturbations in the feedback path that occur in daily use such as caused by chewing, sneezing, or using a telephone handset. The bulk delay shifts the filter response so as to make the most effective use of the limited number of filter coefficients.
A hearing aid according to the present comprises a microphone for converting sound into an audio signal, feedback cancellation means including means for estimating a physical feedback signal of the hearing aid, and means for modeling a signal processing feedback signal to compensate for the estimated physical feedback signal, subtracting means, connected to the output of the microphone and the output of the feedback cancellation means, for subtracting the signal processing feedback signal from the audio signal to form a compensated audio signal, a hearing aid processor, connected to the output of the subtracting means, for processing the compensated audio signal, and a speaker, connected to the output of the hearing aid processor, for converting the processed compensated audio signal into a sound signal.
The feedback cancellation means forms a feedback path from the output of the hearing aid processing means to the input of the subtracting means and includes a first filter for modeling near constant factors in the physical feedback path, and a second, quickly varying, filter for modeling variable factors in the feedback path. The first filter varies substantially slower than the second filter.
In a first embodiment, the first filter is designed when the hearing aid is turned on and the design is then frozen. The second filter is also designed when the hearing aid is turned on, and adapted thereafter based upon the output of the subtracting means and based upon the output of the hearing aid processor.
The first filter may be the denominator of an IIR filter and the second filter may be the numerator of said IIR filter. In this case, the first filter is connected to the output of the hearing aid processor, for filtering the output of the hearing aid processor, and the output of the first filter is connected to the input of the second filter, for providing the filtered output of the hearing aid processor to the second filter.
Or, the first filter might be an IIR filter and the second filter an FIR filter.
The means for designing the first filter and the means for designing the second filter comprise means for disabling the input to the speaker means from the hearing aid processing means, a probe for providing a test signal to the input of the speaker means and to the second filter, means for connecting the output of the microphone to the input of the first filter, means for connecting the output of the first filter and the output of the second filter to the subtraction means, means for designing the second filter based upon the test signal and the output of the subtraction means, and means for designing the first filter based upon the output of the microphone and the output of the subtraction means.
The means for designing the first filter may further include means for detuning the filter, and the means for designing the second filter may further include means for adapting the second filter to the detuned first filter.
In a second embodiment, the hearing aid includes means for designing the first filter when the hearing aid is turned on, means for designing the second filter when the hearing aid is turned on, means for slowly adapting the first filter, and means for rapidly adapting the second filter based upon the output of the subtracting means and based upon the output of the hearing aid processing means.
In the second embodiment, the means for adapting the first filter might adapts the first filter based upon the output of the subtracting means, or based upon the output of the hearing aid processing means.
A dual microphone embodiment of the present invention hearing aid comprises a first microphone for converting sound into a first audio signal, a second microphone for converting sound into a second audio signal, feedback cancellation means including means for estimating physical feedback signals to each microphone of the hearing aid, and means for modeling a first signal processing feedback signal to compensate for the estimated physical feedback signal to the first microphone and a second signal processing feedback signal to compensate for the estimated physical feedback signal to the second microphone, means for subtracting the first signal processing feedback signal from the first audio signal to form a first compensated audio signal, means for subtracting the second signal processing feedback signal from the second audio signal to form a second compensated audio signal, beamforming means, connected to each subtracting means, to combine the compensated audio signals into a beamformed signal, a hearing aid processor, connected to the beamforming means, for processing the beamformed signal, and a speaker, connected to the output of the hearing aid processing means, for converting the processed beamformed signal into a sound signal.
The feedback cancellation means includes a slower varying filter, connected to the output of the hearing aid processing means, for modeling near constant environmental factors in one of the physical feedback paths, a first quickly varying filter, connected to the output of the slower varying filter and providing an input to the first subtraction means, for modeling variable factors in the first feedback path, and a second quickly varying filter, connected to the output of the slowly varying filter and providing an input to the second subtraction means, for modeling variable factors in the second feedback path. The slower varying filter varies substantially slower than said quickly varying filters.
In a first version of the dual microphone embodiment, the hearing aid further includes means for designing the slower varying filter when the hearing aid is turned on, and means for freezing the slower varying filter design. It also includes means for designing the first and second quickly varying filters when the hearing aid is turned on, means for adapting the first quickly varying filter based upon the output of the first subtracting means and based upon the output of the hearing aid processing means, and means for adapting the second quickly varying filter based upon the output of the second subtracting means and based upon the output of the hearing aid processing means.
In this embodiment, the first quickly varying filter might be the denominator of a first IIR filter, the second quickly varying filter might be the denominator of a second IIR filter, and the slower varying filter might be based upon the numerator of at least one of these IIR filters. Or, the slower varying filter might be an IIR filter and the rapidly varying filters might be FIR filters.
In the dual microphone embodiment, the means for designing the slower varying filter and the means for designing the rapidly varying filters might comprise means for disabling the input to the speaker means from the hearing aid processing means, probe means for providing a test signal to the input of the speaker means and to the rapidly varying filters, means for connecting the output of the first microphone to the input of the slower varying filter, means for connecting the output of the slower varying filter and the output of the first rapidly varying filter to the first subtraction means, means for designing the first rapidly varying filter based upon the test signal and the output of the first subtraction means, means for connecting the output of the slower varying filter and the output of the second rapidly varying filter to the second subtraction means, means for designing the second rapidly varying filter based upon the test signal and the output of the second subtraction means, and means for designing the slower varying filter based upon the output of the microphone and the output of at least one of the subtraction means.
The means for designing the slower varying filter might further include means for detuning the slower varying filter, and the means for designing the quickly varying filters might further include means for adapting the quickly varying filters to the detuned slower varying filter.
Another version of the dual microphone embodiment might include means for designing the slower varying filter when the hearing aid is turned on, means for designing the quickly varying filters when the hearing aid is turned on, means for slowly adapting the slower varying filter, means for rapidly adapting the first quickly varying filter based upon the output of the first subtracting means and based upon the output of the hearing aid processing means, and means for rapidly adapting the second quickly varying filter based upon the output of the second subtracting means and based upon the output of the hearing aid processing means.
In this case, the means for adapting the slower varying filter might adapt the slower varying filter based upon the output of at least one of the subtracting means, or might adapt the slower varying filter based upon the output of the hearing aid processing means.
Improvements to the feedback cancellation processing of the present invention include improvements to the fitting and initialization of the hearing aid, and improvements to the feedback cancellation processing. With regard to fitting and initializing the feedback cancellation hearing aid, the feedback path model determined during initialization may be used to set the maximum gain allowable in the hearing aid. This maximum stable gain can be used to assess the validity of the hearing aid design, by determining whether the recommended gain for that design exceeds the maximum stable gain. Further, the hearing aid fitting in the ear canal may be tested for leakage, by testing whether the maximum stable gain computed for the hearing aid with its vent hole blocked is substantially higher than the maximum stable gain computed for the hearing aid with its vent open.
Another fitting and initialization feature allows the use of the error signal plotted versus time in the feedback cancellation system as a convergence check of the system, or the amount of feedback cancellation can be estimated by comparing the error at the end of convergence to that at the start of convergence. The error signal may also be used to do an iterative selection of optimum bulk delay in the feedback path, with the optimum delay being that which gives the minimum convergence error. Or, the bulk delay may be set by choosing a preliminary delay, allowing the zero model coefficients to adapt, and adjusting the preliminary delay so that the coefficient having the largest magnitude is positioned at a desired tap location.
With regard to the feedback cancellation processing, the amplitude of the noise probe signal may be adjusted in response to the ambient noise level in the room (this could also be done as part of initialization and fitting). Another processing improvement involves adding a 0 Hz blocking filter as a fixed component to the feedback path, to remove DC bias. In another improvement, the hearing aid gain may be adjusted as a function of the zero coefficient vector.
Another feedback cancellation processing feature allows the LMS adaptation step size to be adjusted in response to an estimate of the input power to the hearing aid. This power estimate may also be used to determine whether the LMS zero filter update is likely to overflow the accumulator. As another feature, the output power is tested to determine whether distortion is likely.
Another feedback cancellation processing feature replaces the adaptive zero filter with an adaptive gain. In another improvement, the pole filter may be improved by switching or interpolating between two sets of frozen filter coefficients. Another processing feature constrains the gain of the adaptive feedback path filter.


A method for communicating between a processor and a video display monitor is disclosed. In one embodiment, the method includes transmitting digital pixel data from the processor to the video display monitor in a forward direction over two differential wire pairs, and transmitting auxiliary digital data from the processor to the video display monitor in a forward direction over the two differential wire pairs by manipulating the DC offsets in the two differential wire pairs thereby using the two differential wire pairs as a single differential pair.

Most computer systems consist of a processor unit and a number of peripheral devices coupled to the processor unit. The peripheral devices send and receive information to and from the processor and, typically, each peripheral device is separately connected to the processor unit by an individual set of cables, with each set of cables having a number of wires. The wires may be used for transferring information from the processor unit to the peripheral, as in the case of digital pixel data transferred to an active matrix flat panel display; or, the wires may used for transferring digital information from the peripherals to the processor unit, as in the case of digital data transferred from a keyboard or mouse to the processor unit.
FIG. 1 illustrates a conventional computer system 100 having a processor unit 101 and a number of peripherals coupled to the processor. The peripherals include a keyboard 102, a mouse 103, a display 104, a digital camera 105, and a pair of speakers 106a and 106b. As shown in FIG. 1, each of the peripherals is coupled to the processor unit through an individual cable assembly. Accordingly, the display 104 is coupled to the processor 101 through cable assembly 110, the keyboard 102 is coupled to the processor 101 through cable assembly 111, the mouse 103 is coupled to the processor 101 through cable assembly 112, the digital camera 105 is coupled to the processor 101 through cable assembly 114, and the pair of speakers 106a and 106b are coupled to the processor 101 through cable assemblies 115a and 115b. As can be seen from FIG. 1, this conventional computer system 100 requires a large number of wires to be coupled directly to the processor 101. This configuration is undesirable for a myriad of reasons which should be obvious to one of ordinary skill in the art.
In order to reduce the number of wires that the user must connect to a processor unit, information may be sent to and from a hub system where it is then routed to the proper peripheral. The hub system may be designed as a stand alone device or it may, preferably, be implemented within one of the peripherals, with each of the other peripherals being coupled thereto. FIG. 2 illustrates a computer system 200 having a hub system 201 coupled to a processor unit 202. In the prior art embodiment illustrated in FIG. 2, the hub system 201 is implemented within a display 203 and is fully integrated within the display 203. Additional peripherals, such as a keyboard 204, a mouse 205, a digital camera 206 and a pair of speakers 207a and 207b are each coupled to the hub system 201. The hub system 201 acts as a pass through port or routing system. As shown in FIG. 2, the processor unit 202 and the hub system 201 are coupled together by two different cable assemblies 210a and 210b. One of the cable assemblies 210a is used for transferring digital pixel data to display 203, and the other cable assembly is used for serially communicating digital data back and forth between the processor unit 202 and the hub system 201. Digital pixel data intended to be displayed is received over the first cable assembly 210a, retained, and properly processed for display by the display 203. However, the serial digital data intended for any of the other peripherals is received over the second cable assembly 210b, passed through the hub system 201, and routed to the proper peripheral. Accordingly, each of the other peripherals sends information to the processor unit 202 or receives information from the processor unit 202 through the hub system 201 over cable assembly 210b; while the display 203 receives digital pixel data over cable assembly 210a.
In one prior art embodiment, the cable assembly 210a will include four twisted wire differential pairs. This configuration is common in a computer system which uses TMDS communications for the transfer of digital pixel data from the processor unit 202 to the display 203. In a TMDS system, a single twisted wire differential pair is used for each of the primary red, green and blue pixel data streams and a fourth twisted wire differential pair for transmitting a clock signal. Alternatively, the cable assembly 210a may include more than four twisted wire differential pairs depending upon the type of communications protocol used for transferring the digital pixel data. For example, a system which uses an LVDS communications protocol would require five twisted wire pairs for transferring the digital pixel data to the display 203.
FIG. 3 illustrates a prior art system for communicating digital pixel data over a first cable assembly 210a in a first direction from processing unit 202 to display 203; and, for communicating digital data over a second cable assembly 210b in a second direction from any of the peripherals coupled to the hub system of display 203 to processing unit 202. As shown, a transmitter 301 is implemented within the processor 202 for transmitting digital pixel data from the processor 202 to the display 203. A receiver 302 is implemented within the display 203 having a hub system for receiving digital pixel data for display from the processor 202. As indicated earlier, in a system which utilizes a TMDS communications protocol for transferring digital pixel data to display 203, cable assembly 210a is actually comprised of four twisted wire pairs, with a first twisted wire pair 305a used for transmitting red pixel data from the processor 202 to display 203, a second twisted wire pair 305b used for transmitting green pixel data from the processor 202 to display 203, and a third twisted pair 305c used for transferring blue pixel data from the processor 202 to display 203. The fourth twisted wire pair 305d is used for routing a clock signal from the processor 202 to the display 203 for synchronizing the digital pixel data at the receiver 302. Alternatively, the system may use any other appropriate communications protocol for transferring digital pixel data to the display 203, in which case the number of twisted wire differential pairs (or single wires) coupled between the processing unit 202 and the display 203 may vary.
Referring again to FIG. 2, cable assembly 210b will also include multiple wires for transmitting digital data to the processor 202 from each of the peripherals coupled to the hub system of display 203. These wires may use any one of various communications such as Universal Serial bus. The number of wires used in cable assembly 210b is dependent upon the particular system configuration. For example, it is desirable to be able to transmit digital data from the digital camera to the processor, while also transmitting data from the mouse or keyboard and accordingly multiple wires are required. Accordingly, as shown in FIG. 3, the processor unit 202 further includes a receiver 310, while the display 203 with hub system includes a transmitter 315. The transmitter 315 of the display 203 with hub system routes digital information incoming from the other peripherals coupled to the display 203 to the receiver in the processor 202. The prior art embodiment in FIG. 3 shows three twisted wire differential pairs 306a-c which may be used for communicating digital data from the peripherals coupled to the hub system of display 203 to the processing unit 202. It is understood, that in the prior art, any number of twisted wire pairs may be used for transferring such data. In the prior art embodiment illustrated in FIG. 3, the transmitter 315 generates its own clock reference signal on line 306c.
While the computer system illustrated in FIG. 2 may reduce the overall number of cable assemblies coupled directly to the processor 202, it is still undesirable because it requires a large number of wires. Accordingly, what is needed is a simpler system for linking the processor unit with the hub system without requiring multiple cabling assemblies which also reduces the number of wires coupled to the processor, thereby reducing costs and improving the performance of the system.
A method for communicating between a processor and a video display monitor is disclosed. In one embodiment, the method includes transmitting digital pixel data from the processor to the video display monitor in a forward direction over two differential wire pairs, and transmitting auxiliary digital data from the processor to the video display monitor in a forward direction over the two differential wire pairs by manipulating the DC offsets in the two differential wire pairs thereby using the two differential wire pairs as a single differential pair.

Bi-directional data transfer using two pair of differential lines as a single additional differential pair


The present invention provides a cooling device for rack-type electronic equipment. The rack-type electronic equipment is provided with electronic circuit devices having different heating quantities inside an enclosure, and the cooling device has multiple heat pipes for cooling the rack-type electronic equipment. A condenser unit is provided on the upper surface of the enclosure, an evaporator is provided on the back surface of the enclosure, and each electronic circuit device having a different heating quantity is cooled by means of the heat pipes.

Due to recent increases in high performance of electronic components and density growth thereof on a control board, there is significantly increased heat generation from the control board. Also due to recent increases in downsized, densely integration in electronic components and an amount of information to be processed, various cooling methods have been invented, e.g. to effectively cool electronic components close to heated areas and to cool respective racks. (for example, PTL 1)
A conventional cooling device for rack-type electronic equipment is described hereinafter with reference to FIG. 10. As shown in FIG. 10, the conventional rack-type electronic equipment comprises a group of circuit boards 102 including electronic circuits thereon inside enclosure 101 and a cooling device including heat pipe 103 and heat exchanger 104. The group of circuit boards 102 is orderly arranged into a rack shape inside enclosure 101. Heat pipe 103 is disposed to fill a gap between each one of the groups of circuit boards 102. Heat exchanger 104 is disposed on a top of enclosure 101 and heat pipe 103 is connected to heat exchanger 104. Inlet 105 and outlet 106 are disposed at the top of enclosure 101. Air blower 107 disposed close to inlet 105 is activated to pass outdoor air through enclosure 101. An air sucked from inlet 105 is discharged from outlet 106 through heat exchanger 104.
Heat generated from the group of circuit boards 102 warms ambient air. The high-temperature air is cooled by heat exchange with refrigerant in heat pipe 103. Vaporized refrigerant by heat absorption travels upward through heat pipe 103 and moves into heat exchanger 104. The vaporized refrigerant is condensed to liquid by heat exchange with cold outdoor air sucked by air blower 107 in heat exchanger 104 and goes down through heat pipe 103.
The conventional cooling device needs to be designed as an integrated cooling device comprising enclosure 101 and the group of circuit boards 102 because heat pipe 103 is disposed to fill the gap between each one of the group of circuit boards 102. For that reason, heat pipe 103 needs to be designed in response to size and quantity of the group of circuit boards 102.
In the cooling device shown in FIG. 10, since heat pipe 103 forms a cooling cycle for the whole cooling device, it is difficult for the conventional cooling device to deal with different heat quantities generated from each one of the groups of circuit boards 102.

Cooling device for rack-type electronic equipment and data centre

Panasonic Intellectual Property Management Co., Ltd.


A wideband fully integrated two-way radio transmitter (100) includes a voltage controlled oscillator (VCO) (101) for providing a voltage at a radio frequency. A divider (103) is used reducing the radio frequency (RF) signal from the VCO to a an intermediate frequency. A voltage-to-current converter is used for changing the voltage of the intermediate frequency RF signal to an RF current. A transmit buffer is then used for amplifying the RF current supplied by the voltage-to-current converter for amplification by a power amplifier. The fully integrated current mode transmit buffer offers the advantage of amplification over a large bandwidth while providing isolation between the transmit buffer and the VCO.

In a number of modern two-way radio and cellular telephone products, zero intermediate frequency (ZIF) technology is used in the radio receiver. The ZIF operates using the incoming radio frequency signal where it is mixed or heterodyned with an internal local oscillator (LO) at approximately the same frequency. A resultant or intermediate frequency signal is created by this process. This intermediate frequency is at approximately 0 hertz. The intermediate frequency signal is then passed through a respective low pass filter, demodulator, and audio processing circuits where it is output in the form of a recovered audio signal available to a user. This process is generally referred to as direct conversion.
Since the LO and desired frequency are roughly equal, the LO can also conveniently be used to transmit a signal at that same frequency. Thus, a common LO synthesizer can be used to both transmit and receive in the direct conversion two-way radio transceiver. This technique needs only a single voltage controlled oscillator (VCO). In the radio transmitter portion of the transceiver, the VCO is typically run at twice the desired signal frequency and later divided by two down to the desired frequency. When used in this manner, this simple system is ideal for integration onto a single microelectronic silicon chip-commonly known as an integrated circuit (IC). Of course before the transmit signal is passed to a RF power amplifier, the signal is generally buffered and amplified.
Unfortunately problems occur with such a localized system where many RF signals are used in such a manner. The close circuit proximity facilitates signal cross coupling through the common silicon substrate. Therefore one system can adversely react with the other. Additionally, problems also can occur in the amount of RF feedback through circuit parasitics and this can also disrupt the operation of the VCO or synthesizer. The transmit buffer output signal, typically on the order of +5 dBm, must be isolated from the VCO output signal having an amplitude of -20 dBm or less. Thus, a significant amount of RF isolation is necessary to keep the large amplitude of the transmit buffer from interfering with the small VCO signal. The integrated circuit's signal nodes will generally have some parasitic capacitance to a common substrate or node. It is by this common node that the various oscillator and synthesizer circuits interact with one another. By decreasing the resistance at a given circuit's node, the substrate and circuit parasitic coupling can be reduced. This is achieved by using the tx buffer in a current mode operation.
Moreover, each time the IC package pin count is increased, or any external parts are needed in the design of a transmit buffer, an incremental construction cost will occur. This is due to the increase in manufacturing complexity and total part count. Additionally, in many transmit buffer designs external bypass parts are necessary because they are difficult to integrate onto silicon. Further, the bandwidth of the oscillator will depend upon the selection of these devices. Different external parts are often necessary to supply a variation in frequency ranges. This tends to even further complicate already complex manufacturing techniques. External connections other than the output of the IC are highly undesirable in an IC transmit buffer circuit.
Therefore, the need exists to provide a transmitter circuit where the transmit signals on a single chip IC design remain locally isolated while allowing wideband operation, with inexpensive full system integration.

Fully integrated two-way radio transmitter utilizing current mode transmit buffer and method of using same


A drapery rod comprises a ductile wire stiffener which is plastically deformable by manually generated stresses. The ductile wire stiffener is surrounded by a solid cylindrical member made up of resiliently deformable material, such as polypropylene foam. The drapery rod can be plastically deformed to conform to unusually shaped windows, such as semicircles. The ends of the rod may be deformed to provide returns.

I. Field of Invention
This invention pertains generally to the art of structures to be mounted on interior walls for decorative purposes, and more specifically to drapery rods for hanging curtains and draperies near windows.
II. Description of Related Art
In the past, draperies have been hung from rods which were mounted to a wall near a window. Typically, these rods were made of metal and had a straight linear configuration.
Some newer window designs have featured nonrectangular window shapes. As such, a problem has been presented in that the straight drapery rods no longer corresponded to the window's shape. Drapery rods are difficult to form into non-linear shapes, such as semicircles. In addition, applicants recognized the need for a low cost drapery rod which would be adaptable to a variety of window configurations and provide excellent service and attractive appearance at an attractive cost.
The present invention contemplates a new and improved drapery rod which is simple in design, effective in use, and overcomes the foregoing difficulties and others while providing better and more advantageous overall results.


An all-terrain recreational vehicle comprises a frame, a seat assembly, a plurality of tire assemblies, a steering assembly, a power delivery assembly, a water reservoir, a nozzle and an actuation mechanism. The frame includes a padded roll cage and the seat assembly is attached to the frame. The plurality of tire assemblies is attached to the frame. The steering assembly is connected between the frame and at least two of the tire assemblies. The power delivery assembly is connected to at least one of the tire assemblies. The water reservoir is attached to the frame and the nozzle is in fluid communication with the water reservoir. The actuation mechanism is attached to the frame at a remote location from the nozzle. The actuation mechanism is operably connected between the nozzle and the water reservoir for enabling selective dispensing of water from the water reservoir through the nozzle.

By very nature, games are played with the intent of accomplishing a specified objective or objectives. In many cases, a game apparatus used to play a game entirely or largely dictates the specified objective of the game. Accordingly, in such cases, it is the game apparatus itself that correspondingly defines the uniqueness, degree of challenge and intent of the game.
It should be noted that a game apparatus is often used or even conceived as a toy (i.e., not related to facilitating game play). Thus, when not being used for facilitating game play, such game apparatuses may be used strictly in a non-game-like manner (e.g., non-competitive and/or entertainment purposes). Such dual-mode use further adds to the utility and enjoyment associated with some game apparatuses.
The horizon for new games is virtually limitless. Because of the breadth of interests of people and their continual desire for new challenges, games and game apparatuses of all types are continually being devised. With rare exception, so long as a game offers a new challenge, there will be an audience, large or small, willing to play it. Therefore, a game apparatus that offers a challenging new objective is useful to such an audience and offers advantageous functionality relative to other game apparatuses with which the audience has played.

Water-shooting all-terrain recreational vehicle


A semiconductor manufacturing process for forming a sloped contact in a layer of dielectric such as oxide comprises the use of an argon etchant. After a planar oxide layer is formed over a conductor, a photoresist mask defines the etch area. The exposed oxide is etched, thereby forming a sloped sidewall and a contact to the underlying conductor. This etch also forms a corner where the sloped sidewall joins the planar surface. The slope formed in the dielectric layer at this point is noncritical. After the photoresist is removed, a second etch using an inert material such as argon, krypton, or xenon is performed. This etch removes material at the corner at a rate of up to four times the removal rate at the sidewall and the planar surface. A faceted edge is thereby formed in the dielectric layer. The material that is removed to form the facet is redeposited over a portion of the sidewall and the conductive layer, and thereby improves the slope of the contact.

During the formation of semiconductor devices such as dynamic random access memory (DRAMs), static random access memory (SRAMs), microprocessors, etc. insulating layers such as silicon dioxide, phosphorous-doped silicon dioxide, silicon nitride, etc. are used to electrically separate conduction layers such as doped polycrystalline silicon, aluminum, refractory metal silicides, etc. It is often required that the conduction layers be interconnected through holes in the insulating layer. These holes are referred to as contacts or vias and often must exhibit specific characteristics such as a sloped or tapered profile. The sloped profile is necessary so that the step coverage of the conduction layer into the hole is of adequate thickness. Standard techniques for deposition of the conduction layers include sputtering and evaporation. Both of these techniques provide step coverage of the contact hole that is sensitive to the contact profile. Vertical contact profiles often result in unacceptable step coverage. Highly sloped contact profiles result in good step coverage, however, the contact is often excessively enlarged in this process. This enlargement may cause unwanted electrical shorting between or within conduction layers, and may also reduce the density of the circuit features, that is, limit how close together the devices can be placed.
Providing adequate contact slope is critical to achieving acceptable contact step coverage. Several methods of producing sloped contacts are known. These can be grouped into the general categories of wet etch, wet/dry etch, reactive ion etch (RIE), isotropic/RIE etch, and resist erosion technique.
The wet etch technique uses standard photoresist exposure and development techniques to print the required contact pattern on the insulating layer. To further enhance the slope of this process, CF.sub.4 /O.sub.2 plasma pretreats have been used to promote preohmic taper. The plasma pretreat is difficult to control and provides non-uniform tapers. The profile of the sides of the photoresist opening are vertical for this type of etch. As the insulating layer is etched, with NH.sub.4 F:HF acids of the like, the photoresist will protect the areas not exposed. The chemical wet etch will etch the insulating layer isotropically so that the contact profile is sloped. This process significantly enlarges the contact area due to the nondirectionality of the wet etch. In addition, the acids used suffer from high particulate counts which contaminate the contact area.
The wet/RIE technique process has the disadvantage of requiring two separate etch processes and still uses the acid as in the wet etch. To create an initial slope profile followed by a less sloped profile in the oxide contact (funnel shaped preohmic), two photoresist steps are used each requiring a different acid and/or dry etch to accomplish each objective. Problems resulting from this process include: resist adhesion and phosphorous concentration differences on the oxide surface that cause erratic size and taper of preohmics; excessive undercutting of the preohmics caused by variations in the acid strength from batch to batch, changes in buffering concentrations inherent in the acid solutions (crystals), enhanced etch rate at stress locations, and temperature variations, and; alignment tolerances required result in significant photoresist redo rates.
The isotropic/RIE etch technique first etches the contact pattern delineated by the photoresist into the underlying glass substrate using a high pressure isotropic plasma etch (CF.sub.4, 8.5%). The etch is completed with a selective RIE etch step to remove the remaining oxide. The isotropic step of this method is described in U.S. Pat. No. 4,361,599 issued to Robert L. Wourms. This technique results in a cusp shaped taper rather than a sloped taper, may have decreased process stability, and may require additional handling.
In the resist erosion technique, the required contact pattern is printed on the insulating layer, again using standard photoresist exposure and development techniques. Next, the photoresist layer in baked such that the resist flows giving the walls defining the openings in the resist a tapered or sloped profile. Next, the device is dry etched in an environment that will etch the substrate and the resist at the same time. This will replicate the sloped resist profile into the substrate. The disadvantages in this process are that a relatively thick resist layer is required, the scaling of the process does not lend itself to very large scale integration geometries, and the reproducibility across one or more wafers of the particular slope of the baked resist is very poor.
Another type of the resist erosion technique uses resist faceting. First, standard photoresist exposure and development techniques are again used to print the required contact pattern on the insulating layer. A dry etch of the oxide is then conducted using an in situ resist tapering process. By using a low pressure and high oxygen flow etch, the corners or edges of the resist will etch faster than the planar resist. This results in a sloped resist profile referred to as resist faceting. This slope is then replicated into the substrate using the same technique described for the resist erosion technique.
Another form of resist erosion technique is a two step method and uses a two-layer photoresist mask. This is described in Saia, et al., "Dry Etching of Tapered Contact Holes Using a Multilayer Resist", J. Electrochemistry Soc.: Solid-State Science and Technology v. 132 (August, 1985). Here the authors describe the process using a two-layer photoresist mask, where the bottom layer is poly (methyl methacrylate) (PMMA) and a plasma gas etch containing CHF.sub.3, argon and oxygen. The photoresist to oxide etch rate ratios ranged from 1.5:1 to 1:1.
One of the drawbacks of resist faceting techniques is the limit of the taper produced in the substrate. In order to achieve an appreciable sloped resist profile, a large amount of the resist must be consumed during the faceting step. This resist consumption requires both thickening of the resist and limiting of the of the facet etch time, which is approximately one-half of the total etch time, to prevent resist break through and etching to areas once protected.
The faceting process increases the contact size delineated by the resist prior to the final etch step that removes remaining dielectric. The disadvantages of this technique include the enlargement of the base of the contact beyond the original size delineated in the resist. The final facet etch step, that is required to clear the oxide, will tend to destroy the slope character of the contact.
In general, as devices and line widths have become smaller, wet etching has proved unsuitable for fine line etching below about 3 .mu.m. In addition, profile control has also driven the industry in the direction of plasma (dry) etching. Overviews of etching are reported in Weiss, "Plasma Etching of Oxides and Nitrides", Semiconductor International, p. 56 (February, 1983) and in Coburn, "Pattern Transfer", Solid State Technology, p. 117 (April, 1986).
An article by Bergendahl et al., "A Flexible Approach for Generation of Arbitrary Etch Profiles in Multilayer Films", Solid State Technology, 107 (November, 1984), describes an additional method known as multistep contour (MSC) etching. MSC is describes as combining independently optimized process modules to form a complete process. The process described in the Bergendahl article has the problems of filament development and excessive bulk resist removal, and stresses induced by power pulses during all process steps.
While the ideal contact through a dielectric layer between two conduction layers would be a completely metal filled truly vertical contact hole or via, technology to reliably provide such contacts is not yet in place. Therefore, there is still a great need for the ability to control the slope of the contact walls so as to permit good step coverage and contact to the lower conductive layer by the overlying conductive layer.

High accuracy via formation for semiconductor devices


A nonsacrifical laser hardened structure and method protects against incident high energy irradiation. A very thin outer face sheet with a reflective outer surface is laminated to a foam core which is further laminated to a support structure. The foam core includes liquid and vapor passages. A supply of liquid working fluid impregnates the foam core. A portion of incident irradiation energy is first reflected from the outer face sheet and substantially all the remaining irradiation energy conducted through the face sheet to be absorbed at the back of the face sheet into heat of vaporization of the liquid working fluid. Additional liquid working fluid is supplied to the back of the face sheet by capillary action through the foam core, and additional liquid working fluid is resupplied to the foam core through the liquid passages. Working fluid vapor is removed through the foam vapor passages. Another embodiment of the invention includes a highly reflective coating as the reflective outer surface of the outer face sheet. The preferred embodiment uses sintered aluminum as the foam core. The liquid working fluid may be supplied under pressure from a central storage area.

The present invention relates generally to laser hardened structures, and more specifically to nonsacrificial laser hardened structures.
Protection of aircraft and spacecraft from high energy laser irradiation can be accomplished by laser hardening of the outer surface of the craft. Prior art laser hardening absorbs laser irradiation primarily by solid to gas transition of sacrificial materials. This requires using very conservative amounts of material and covering the energy absorbing material over the entire surface to be protected. Therefore, the weight of required material may be prohibitive.
Additionally, the use of sacrificial material limits the ability to protect against repeated or sustained laser irradiation.
It is, therefore, a principal object of the present invention to provide a laser hardened structure that absorbs laser energy without sacrificing material.
Another object of the present invention is to provide a lightweight laser hardened structure.
A feature of the present invention is that additional energy absorbing material can be stored in a central location and automatically supplied to the area encountering the laser attack.
An advantage of the present invention is that it is effective against sustained or repeated laser irradiation.
Another advantage of the present invention is that it can be made to serve as a load bearing member of the structure of the craft.
These and other objects, features, and advantages of the present invention will become apparent as the detailed description of the certain representative embodiments proceeds.

The United States of America as represented by the Secretary of the Air Force


A system may receive a transaction request from a user device, and request an in-app cryptogram from a network software development kit (SDK) on the user device. The in-app cryptogram may include an unpredictable number, an application transaction counter (ATC), and a card verification result (CVR), and the ATC may be extracted from a limited use payment credential (LUPC). The system may transmit a token, a token expiry, and a token data block for an assessment by a payment network, with the token data block including the token, the token expiry, the ATC, and/or the in-app cryptogram. The system may further receive a request from the payment network to update the LUPC on the user device, and attest that the user device is secure in response to the request from the payment network to refresh the LUPC on the user device.

Modern consumers often shop online with increasing regularity. In fact, e-commerce comprises a significant portion of total sales for many merchants. The increase in e-commerce transactions may be attributable in part to convenience and the ease of completing transactions. However, as consumers become accustomed to the ease of online transacting, inconveniences or inefficiencies may frustrate consumers into abandoning purchases that they would otherwise complete. For example, a consumer may become frustrated when their purchase account card is out of reach or the page resets causing personal information already entered to be lost. Such seemingly small hurdles to completing the transaction may scuttle the purchase.
The availability of digital wallet applications increases as more users acquire digital devices. Digital wallets may streamline the payment protocol in some instances and avoid some of the potential pitfalls of traditional web transactions. However, stored transaction account information makes digital wallets and user devices prime targets for theft and fraud. Thus, the use of a digital wallet for in-application and/or in-browser purchases may present increased security risks.

Systems and methods for in-application and in-browser purchases

AMERICAN EXPRESS TRAVEL RELATED SERVICES COMPANY, INC.


The present invention comprises a method for controlling a threshold voltage through a semiconductor substrate of a first conductivity type (the type being an n- or p- type in a MOSFET) without the need for a blanket implant for either long or short channel devices. A gate structure having opposed lateral edges is formed adjacent a surface of the semiconductor substrate and over a channel region of the substrate. The substrate is rotated around a rotation axis normal to the surface of the substrate to a first rotation position. Ions of a first conductivity type are then implanted into the channel region, using the gate structure as a mask, at an oblique angle relative to the surface normal of the substrate. The substrate is then rotated to a second rotation position approximately 180 degrees from the first rotation position. Ions of the first conductivity type are then implanted into the channel region, using the gate structure as a mask, at the oblique angle relative to the surface of the substrate.

This invention relates generally to MOSFET devices and more particularly to a simplified process for doping CMOS devices to more easily and efficiently regulate their threshold voltage characteristics.
Designing MOS devices that possess adequate threshold voltage behavior at both long and short channel lengths is a difficult process because many of the process components that affect threshold voltage interact at short channel lengths. A conventional process flow involves two steps. A first VT-shift implantation step is performed to fix the threshold voltage (V.sub.T) at long channel lengths. Secondly, a punchthrough implantation step is performed which prevents punchthrough and mitigates roll-off at short channel-lengths. "Roll off" is a term used to describe the reduction of threshold voltage with decreasing gate length due to the interaction of the source and drain regions of a MOSFET. An example of this effect is shown by line 86 in FIG. 7. Typically, this last step is accomplished using a high-angled implant of four discrete rotations performed after the gate of the CMOS device is etched.
This process is further complicated in CMOS technology where surface NMOS and PMOS transistors exist on the same wafer. Both devices are desired to have a particular threshold voltage where the characteristic behavior of the threshold voltage is predictably even over a range of channel lengths. Because the charge carrying mechanism is different in the two devices, it is impossible to induce a suitable threshold voltage for each device using a single mask and implant step. For instance, for a N-channel device, an implant of p-type dopant is required whereas for P-channel devices, an implant of n-type dopant is required.
Each of these VT-shift and masking steps increases the manufacturing costs for CMOS-based integrated circuits.
In addition to differences between N- and PMOS devices, there are also different problems associated with long and short channel devices.
Accordingly, the process steps used in conventional systems to stabilize the threshold voltage has traditionally been different. For instance, short channel devices suffer from "roll-off" where the threshold voltage drops sharply with decreasing channel lengths where channel-length can never be precisely controlled from device to device. Thus, in a 0.35 micron process, the MOSFET devices on any given wafer might have channel lengths which can vary from between 0.32 to 0.38 microns. If there is a precipitous roll-off in the threshold voltage, the threshold voltages can vary from between 0.3 to 0.5 volts. To reduce this so-called "short channel effect", punchthrough implants can be disposed adjacent the channel region of MOSFET devices according to a variety of well-known methods, thereby preventing a punchthrough of current at less than the desired threshold voltage for the device. At longer channel lengths, CMOS devices generally exhibit a drop off in their threshold voltage if punchthrough implants are used without corresponding VT-shift implants.
Accordingly, a need remains for a simplified universal process for setting the threshold voltage of various sizes and types of CMOS devices.

Method for artificially-inducing reverse short-channel effects in deep sub-micron CMOS devices


The present invention relates to metal filaments for use as fuel additives for rocket propellants, explosives, and other pyrotechnic devices. Preferred filaments are those such as zirconium, niobium and titanium (and alloys thereof) which have very high heat of combustion.

In rocket propellants, grenades, and various explosive devices, metal powders are often added to increase the overall heat of combustion and otherwise control the rate of burning of a propellant or explosive. (For example, "Metal Powders for Fuel Propellant, Pyrotechnics, and Explosives" Fauth, pp 597-605, and "Explosivity and Pyrophoricity of Metal Powders" Dahn, pp 194-200, ASM Handbok Vol. 7, 1984. ) While zirconium and similar powders have been employed in the past, they are extremely hazardous to use due to the pyrophoricity of zirconium powders and the tremendous heat generated by the burning of such powders. Known techniques for producing such zirconium powders involve reduction processes which provide a fairly wide range of particle sizes, some of which can be extremely fine and almost impossible to handle under conditions other than completely inert ambient atmospheres. Also, the wide range of particle sizes which result from most processing operations can give undesirable burning characteristics which are more difficult to predict and control. The normal methods for the formation of powders involve continued mechanical diminution (i.e. grinding, ball milling, impact crushing, etc.) all produce particles which are extremely nonuniform, irregular and contaminated. These methods often form "dust" (e.g. airborne sub particles). This is the nature of these processes. The powder becomes more dangerous to handle as the particles get smaller, and the degree of surface contamination also increases, resulting in variability in ignition and spontaneous combustion problems. Due to the fact that sub micron powders are subject to agglomeration the actual surface area could be considerably larger than if we assume the particles are separate solid spheres and thus create unpredictable performance.
The most common metal used is Aluminum as an addition to solid rocket propellant and explosive devices. The amount of Aluminum can be up to 20% of the total charge. Other metals are also used and these are Magnesium, Titanium and Zirconium. These metals are generally added in form of very fine particles or powders. In most cases however, the full utilization of the theoretical performance of these metal additions has not been achieved for a variety of reasons. In general, the main factors which govern the performance are the same parameters which control the ignition and subsequent combustion of the metal particles. The rate of combustion can vary from burning (Deflagration) to very rapid detonation of the metal as in explosives. These factors are:
1. Size and shape of the metal in fine dispersion. PA1 2. Surface area/volume ratio. PA1 3. Chemical purity of the bulk metal and its surface. PA1 4. The real and apparent density of the metal. PA1 5. Surface contamination resulting from processing or for safety reasons. PA1 6. Nature of the prepared surface which relates to the method of preparation . . . i.e. made by ball milling, grinding or various chemical or electro-chemical methods. PA1 7. The physical properties such as melting point (in the case of Aluminum, the low melting point results in both particle agglomeration and melting prior to ignition and combustion). PA1 1. Metals which are uniform in both size and shape such that reliable reproducible ignition and complete combustion can take place. PA1 2. The metal should be produced in very fine state of dispersion. PA1 3. The metal should be completely dense and not porous or agglomerated powders. PA1 4. The surface of the bulk metal should be of high purity, free of contaminants. PA1 5. Very little size variation to minimize the danger of handling and processing. PA1 6. The metal can be manufactured economically and safely in large quantities.
Considerable attention has been spent on optimization of the fuel, oxidizer and binder portions of rocket and explosive devices. In all cases, the metal addition has not received similar attention. As a result, what has been available has been essentially what the powder metallurgy industry can produce and this has resulted in less than desired performance. The following are the most desirable characteristic for metal fuel additions:


Systems and methods for reducing temperature variation during burn-in testing. In one embodiment, power consumed by an integrated circuit under test is measured. An ambient temperature associated with the integrated circuit is measured. A desired junction temperature of the integrated circuit is achieved by adjusting a body bias voltage of the integrated circuit. By controlling temperature of individual integrated circuits, temperature variation during burn-in testing can be reduced.

Highly integrated semiconductor devices, e.g., microprocessors, frequently dissipate a great deal of heat, particularly when operated at elevated temperatures and voltages to screen for defects during burn-in operations. Such heat dissipation is deleterious during burn-in operations, conventionally requiring complex and expensive heat sinking, e.g., water baths and/or liquid metal cooling, and expensive test chambers with very high cooling capacities.

System and method for reducing temperature variation during burn in


A system for the pretreatment and primer electrodeposition of an assembly is provided. The system includes one or more large envelope, heavy payload robots configured to grasp the assembly and arrange the assembly in a substantially vertical orientation. The one or more robots are further configured to vertically raise and lower the assembly. A tank is configured to receive the assembly in a substantially vertical orientation. The tank is further configured to impart a liquid onto the assembly. The liquid imparted onto the assembly is configured to improve the corrosion resistance of the assembly.

An automobile assembly plant can have at least three main areas: the body shop, the paint shop and the assembly area. Assemblies including automotive car bodies, panels and large parts are conveyed from the body shop to the paint shop. After entering the paint shop, the assemblies require a series of metal pretreatment processes, including surface cleaning, conversion coating, and primer paint electrodeposition. In many instances, the assemblies are formed from bare steel structures and panels that are combined together using known processes. Prior to passing the assemblies to the sealer area and finally to the decorative topcoat paint application, the assemblies are hung from a conveyor and passed through several spray stations, draining stations, immersion tanks, drying stations and, finally, a baking oven to dry an electrodeposited primer material. The processes prior to the baking oven can consist alternately of several spraying, draining, drying and immersing zones. The length of the zones can vary and are generally based on production throughput and corresponding conveyor speed. The number of zones is extensive and a typical paint shop may have in the range of 40 such zones or steps in the overall process. The amount of space required for this overall process is large and can require a building size of approximately 16,000 m2. The amount of water and energy required for this process makes it attractive for efficiency improvement.
Various attempts to improve the processes in the pretreatment and electrodeposition area of the paint shop have been considered. In certain efforts, one to three additional degrees of freedom have been added to the conveyor so that the assemblies can be immersed in a non-horizontal position and rotated vertically or horizontally while entering in or leaving the immersion tank. Other efforts have included improvements in the electrical contact with the assemblies during the conveying process. More recent advancements include the motorization of each assembly carrier and the electrical isolation of the assemblies from the conveyor or grounded contact. The more recent advancements have mostly targeted the processes involving the primer paint electrodeposition immersion tank. Only minor process improvements in the cleaning, conversion coating and rinsing processes have been realized.
While some of these process changes have provided improvements in the process, the additional cost, complexity, and maintenance requirements do not always merit changing from the traditional approach. As one example, each conveyance carrier must have a significant cost increase to provide the additional rotary axis. Additionally, the rotational component can be subjected to harsh conditions while it is often submerged with the assembly. Paint must be occasionally stripped from the submerged portion of the part holding carriers and since they are now more geometrically complex, the paint is more difficult to remove. The harsh environment also requires additional maintenance on the submersed portion of the rotary joint, including greasing, seal replacement, and electrical contact repair.
It would be advantageous if the paint shop processes could be improved while at the same time reducing capital cost and improving system maintainability.

Robotic pretreatment and primer electrodeposition system