The present invention is a method of determining the presence of keratin, particularly hard keratin, such as exists in mammalian hair and feathers, and objects comprising such materials. The method of the present invention also includes displaying information derived from such a determination, as well as a measurement method followed by transmission of data to a remote processing site for analysis or display. The invention also includes devices for carrying out the determination, display and/or transmission.

The present invention relates to a method of detecting hard keratin (mammalian hair, feathers, etc.) from reflected light.
In many instances it is desirable to be able to detect the presence of hard keratin (mammalian hair, feathers, etc.) in an area, particularly in areas where it is desirable to be able to determine the presence of organic materials comprising or made from hard keratin (mammalian hair, feathers, etc.).
It is particularly desirable to be able to detect the presence of hard keratin (mammalian hair, feathers, etc.) in a manner that is convenient and provides relatively immediate results so that an operator may take action in any one of several applications for the present invention.
It is also desirable to be able to signal an operator in a manner that would allow an operator to be aware of such detection.
In many instances it would be beneficial to be able to visualize the results of such detection in order that an operator may visually identify organic material objects comprising or made from hard keratin (mammalian hair, feathers, etc.).
In addition to the features mentioned above, objectives and advantages of the present invention will be readily apparent upon a reading of the following description and through practice of the present invention.

Method and apparatus for detecting organic materials and objects from multispectral reflected light


A hologram containing information recorded such a manner that it is difficult to read. A Lippmann hologram (10) contains photoelectrically readable information (13) recorded so as to be reconstructible only with a specific invisible wavelength (6) in the infrared or ultraviolet region. It is difficult to read the information recorded on the hologram unless information about the wavelength of diffracted light (14) for reconstruction is given. The hologram is also difficult to forge and hence suitable for security purposes.

The present invention relates to a hologram and, more particularly, to a Lippmann hologram which is reconstructible only with infrared or ultraviolet rays and hence suitable for security purposes.
It is a known practice to provide a hologram, which contains the record of a three-dimensional image symbol, pattern, etc., on a card or a bankbook, for example, as an integral part thereof in order to guarantee that the card or bankbook is genuine and it is not a forgery, and to reconstruct the hologram by illumination with specific reconstructing light to thereby verify that the card or bankbook is genuine.
However, most holograms used for such security purposes are simple diffraction grating patterns, image holograms, or Fresnel holograms. Therefore, these holograms can be readily reconstructed and read with simple illuminating light for reconstruction, and it is not always difficult to read and forge them.


The invention relates to a process for preparing a compound of the formula ##STR1## comprising reacting a bromo-substituted pyridine with an amine of the formula NHR.sup.5 R.sup.6, reacting the resulting amide with an iodo-halomethyl-substituted compound and cyclizing the resultant product, wherein R, R.sup.1, R.sup.2, R.sup.3 and R.sup.4 are as defined in the specification; also claimed are a compound of the formula ##STR2## and a process for preparing it from the corresponding halo-substituted benzoic acid.

This invention provides an improved process for preparing intermediates useful in the preparation of tricyclic compounds known as antihistamines and as inhibitors of farnesyl protein transferase (FPT). In particular, the compounds of this invention are useful in the preparation of antihistamines such as those disclosed in U.S. Pat. Nos. 4,282,233 and 5,151,423, and of FPT inhibitors disclosed in International Application No. PCT/US96/19603, filed Dec. 19, 1996.

Synthesis of intermediates useful in preparing tricyclic compounds


A method for presenting video on a local monitor and a remote monitor includes encoding an original video signal to produce a first compressed video signal. Using the first compressed video signal, the video signal is also encoded to produce a second compressed video signal. Both the first and second compressed video signals are transmitted to a local terminal at which the first and second compressed video signals are decoded to produce first and second decoded video signals. A first decoded version of the video signal is produced from a combination of the first and second decoded video signals. Only the first compressed video signal is transmitted to a remote terminal at which a second decoded version of the video signal is recovered from only the first compressed video signal.. The first compressed video signal may be produced by motion compensation temporally encoding and spatially encoding the original video signal. The second compressed video signal may be produced by both spatially and motion compensation temporally decoding the first compressed video signal and subtracting each pixel of each picture thereof from a corresponding, spatially and temporally aligned pixel of a picture of the original video signal to form a difference video signal. The difference video signal is then only spatially encoded to produce the second compressed video signal.. To produce the first decoded version of the original video signal, the first compressed video signal may be both spatially and motion compensation temporally decoded and the second decoded video signal may be only spatially decoded. Each pixel of each picture of the second decoded video signal may be added to a corresponding temporally and spatially aligned picture pixel of the first decoded video signal.

Several techniques are known for encoding (i.e., compressing) video to produce a compressed video signal and for decoding such a compressed signal. See ISO/IEC IS 13818-1,2,3:Generic Coding of Moving Pictures and Associated Audio: Systems, Video and Audio ("MPEG-2"). FIG. 1 depicts an encoder 10 and decoder 12 according to an MPEG-1, or MPEG-2 main profile encoding and decoding standard. An original digital video signal V is inputted to the encoder 10. The video signal V is organized into macroblocks. Each macroblock includes a number of luminance blocks and a number of chrominance blocks. Each block is an 8.times.8 array of pixels.
Some macroblocks are only spatially encoded by spatial encoder 14 of the encoder 10. Other macroblocks are both spatially and temporally encoded using spatial encoder 14 and temporal encoder 16 of the encoder 10. Macroblocks that are only spatially encoded are outputted directly via output A to the spatial encoder 14. (Such output is shown as achieved by a switch 13 which may be implemented using software, control signals, etc.) Temporally encoded macroblocks are inputted to the subtractor 18 of the temporal encoder 16 to produce prediction error macroblocks. Prediction error macroblocks are outputted via output B to the spatial encoder 14. The spatial encoder 14 includes a discrete cosine transformer 20 which converts each block of each macroblock to spatial frequency coefficients. The spatial frequency coefficients are quantized by a quantizer 22 (and scanned according to some predetermined "zig-zag" or "alternate scan" ordering).
In temporally encoding a macroblock, a prediction macroblock is selected for each to-be-encoded macroblock, which prediction macroblock is subtracted from the to-be-encoded macroblock in the subtractor 18. The selection of a prediction macroblock may be made as follows. One or more pictures that precede and follow a to-be-encoded picture may be designated as reference pictures from which prediction macroblocks are selected. (Herein "picture" means field or frame as per MPEG-2 parlance.) Such reference pictures are encoded and decoded using the encoder 10 (and may themselves have been temporally encoded). A search is performed in each available reference picture to identify the macroblock therein that most closely matches the to-be-encoded macroblock of the to-be-encoded picture. This best matching macroblock is then selected as the prediction macroblock for the to-be-encoded macroblock. The prediction macroblock may be located in a reference picture that precedes the to-be-encoded picture, a reference picture that follows the to-be-encoded picture or may be an interpolation of multiple available candidate prediction macroblocks, each from a different reference picture. In some pictures, called P-pictures, the prediction macroblock candidates may only originate in one or more preceding pictures (or an interpolation thereof). In other pictures, called B-pictures, the prediction macroblock candidates may be selected from a preceding or following picture (or an interpolation thereof). In yet other pictures, called I-pictures, no prediction is formed. Rather, each macroblock is only spatially encoded. (Such spatially only encoded macroblocks are sometimes referred to as "intra macroblocks", whereas motion compensated temporally encoded macroblocks are sometimes referred to as "inter macroblocks"). In addition, if no adequate prediction macroblock candidate can be found for a macroblock in a P or B picture, the macroblock may be spatially only encoded.
The temporal encoder 16 includes a decoder 24. The decoder 24 includes a dequantizer 26 for dequantizing the coefficients output by the spatial encoder 14. The dequantized coefficients are inverse discrete cosine transformed by an inverse discrete cosine transformer 28 to produce pixel values. If the decoded macroblock was only spatially encoded, the decoded macroblock may be directly stored in a picture memory 30 via output C. If the decoded macroblock is a prediction error macroblock, the appropriate prediction macroblock is retrieved from the picture memory 30 (as described below) and added to the decoded prediction error macroblock in an adder 32. The macroblock of pixels thus formed is stored in the picture memory 30 via output D. Illustratively, only decoded macroblocks of reference pictures are stored in the picture memory 30.
The selection of the prediction macroblock is achieved as follows. The next to-be-encoded macroblock of the currently encoded picture is inputted to a motion compensator 34. The motion compensator 34 also receives from the picture memory 30 pixel data of reference pictures that may be used to predict the next to-be-encoded macroblock. Illustratively, the motion compensator 34 uses a block matching technique to identify the best matching macroblock (or interpolated mac roblock) from the reference picture(s). According to such a technique, multiple candidate prediction macroblocks are extracted from the available reference pictures and compared to the to-be-encoded macroblock. Each candidate prediction macroblock is shifted temporally with respect to the encoded macroblock (because the candidate prediction macroblocks originate from a different picture in time than the to-be-encoded block) and are spatially shifted relative to the to-be-encoded macroblock in increments as low as 1/2 pixels. The candidate prediction macroblock that best matches the to-be-encoded macroblock is selected as the prediction macroblock for temporally encoding the to-be-encoded macroblock. The prediction macroblock is identified by its temporal and spatial shift, referred to as a motion vector MV. The motion vector MV is outputted from the temporal encoder 16. In addition, such a motion vector MV may be saved (e.g., in picture memory 30) for later identification of the prediction macroblock when decoding the picture in decoder 24.
The spatially encoded macroblock and prediction error macroblock coefficient data and the motion vectors MV are furthermore entropy encoded by run-level, variable length encoder 36. The data may be stored in a buffer 37 that models the occupancy of a buffer of known size at the decoder. To ensure that the decoder's buffer does not overflow or underflow, the number of bits produced per encoded macroblock or prediction error macroblock may be adjusted using a quantizer adaptor 39. (In addition, pictures may be skipped and stuffing data may be appended before the beginning of selected encoded pictures.) The compressed video signal (bitstream) thus produced is outputted via a channel (which may be a transmission medium or a digital storage medium/record carrier, such as a magnetic disk, optical disc, memory, etc.) to the decoder 12. (For sake of brevity, the encoding of audio data, and the encapsulation of the compressed video and audio signals in a system layer stream, such as a transport stream or program stream, and a channel layer format, have been omitted in this discussion.)
The decoder 12 has a buffer 33 in which the received compressed video signal is temporarily stored. The bits of the compressed video signal are outputted to a variable length, run-level decoder 38 which performs the inverse operation as the variable length encoder 36 to recover the motion vectors MV and macroblock and prediction error macroblock coefficient data. The motion vectors MV and macroblock coefficient data are inputted to a decoder subcircuit 40 which is analogous to the decoder 24. The decoder subcircuit 40 decodes the video to produce decoded video DV for presentation.
MPEG-2 also provides scalability layers. See B. HASKELL, A. PURI & A. NETRAVALI, DIGITAL VIDEO: AN INTRODUCTION TO MPEG-2, ch. 9, p. 183-229 (1997). FIG. 2 shows a spatial scalability encoder 42 and decoders 44 and 46. The spatial scalability encoder 42 may be constructed simply as follows. A video signal is inputted to a spatial low pass filter or decimator 48 to produce a lower spatial resolution version of the video signal. A lower or base layer encoder 12 encodes the low resolution version of the video signal to produce a lower layer or base layer compressed video signal LLV. The base layer compressed video signal LLV is a fully and independently decodable and presentable video signal.
Next, an enhancement layer compressed video signal ELV is formed as follows. The full resolution version of the video signal V is predictively encoded in the spatial enhancement encoder 51. However, each temporal prediction macroblock produced by the motion compensator 34 of the spatial enhancement encoder 51 is inputted to a subtractor 52. The base layer compressed video signal LLV is decoded in a decoder 12 and interpolated in a spatial interpolator 50 to the full resolution of the original video signal V. This base layer decoded video signal, which is reconstructed from the base layer compressed video signal, contains reconstructed macroblocks which are used as spatial predictors. That is, the reconstructed macroblocks are fed to the subtractor 52 where they are subtracted from corresponding temporal prediction macroblocks produced by the motion compensator 34. (The spatial prediction macroblocks may be weighted by subtractor 52 before they are subtracted from the temporal prediction macroblocks). The prediction error macroblocks thus formed are then spatially encoded as described above to form an enhancement layer compressed video signal ELV.
Note that both the enhancement layer and base layer encoders 10 and 51 are similar to that described above and both form temporal predictions. This means that a spatial scalability encoder 10,51 must have two picture memories 30, 30' (i.e., capacity to store reference pictures for performing block matching at both the base layer and enhancement layer).
Two types of decoders are permissible for the spatial scalability profile encoded video signal. A first type of decoder 44 uses a decoder 12 of similar construction as shown in FIG. 1 to decode only the base layer compressed video signal LLV to produce a lower fidelity decoded base layer video signal DVL. A second type of decoder 46 decodes both the base layer compressed video signal LLV and the enhancement layer compressed video signal ELV. A base layer decoder 12 of the decoder 46 decodes the base layer compressed video signal LLV. A spatial interpolator 50 interpolates the base layer decoded video signal to the full resolution of the original video signal V. An enhancement layer decoder 53 decodes the enhancement layer compressed video signal. An adder 54 selectively adds (weighted) reconstructed macroblocks of the interpolated, decoded base layer video signal to prediction macroblocks reconstructed from the enhancement layer compressed video signal in order to reconstruct an enhanced fidelity enhancement layer video signal DVE.
FIG. 3 shows an SNR scalability encoder 56 and decoders 58 and 60. The encoder 56 is very similar as before with the following differences. As before, the spatial encoder has a quantizer 22 which outputs quantized coefficients to a run-level, variable length encoder 36. The quantized coefficient signal i.s dequantized by a dequantizer 26. The dequantized coefficient signal is subtracted from the original coefficient signal (outputted from the discrete cosine transformer 20) in a subtractor 64. The error signal thus produced is quantized in a second quantizer 22' to produce a quantizer error signal. The quantizer error signal is run-level and variable length encoded in a second run-level, variable length encoder 36'.
The decoder 66 of the temporal encoder 68 of the encoder 56 has a first dequantizer 26 which receives the quantized coefficients outputted form quantizer 22 and dequantizes them. The decoder 66 also has a second dequantizer 22' that receives the quantized error coefficients outputted from quantizer 22' and dequantizes them. These two dequantized coefficient signals are then added together in an adder 70. The rest of the encoder 56 is the same as in FIG. 1.
The encoded signal outputted from the run-level, variable length encoder 36 of encoder 56 is a fully independently decodable base layer compressed video signal LLV. Such a signal can be received at a base layer decoder 60 which has a similar structure as decoder 12.
The encoded signal outputted from the variable length encoder 36' of encoder 56 is an enhancement layer compressed video signal ELV which can only be decoded in conjunction with the base layer compressed video signal LLV. An enhancement layer decoder 58 has two run-level, variable length decoders 38, 38' for run-level and variable length decoding the base layer compressed video signal LLV and the enhancement layer compressed video signal ELV, respectively. These decoded video signals are then fed to dequantizers 26 and 26', respectively which dequantize these signals. Adder 70 then adds the two dequantized signals together prior to inverse discrete cosine transformation. The remainder of the decoding process is similar to before.
MPEG-2 also has a data partitioning profile and a temporal scalability profile. In the data partitioning profile, the bits of selected quantized coefficients are partitioned into a low precision portion and a precision extension portion. The precision extension portion, which serves solely to distinguish close quantization coefficient levels, is formed into an enhancement layer compressed video signal, whereas the remainder of the original encoded video signal forms a base layer compressed video signal. According to the temporal scalability profile, an original video signal is decimated in time to form a lower temporal resolution video signal. The lower temporal resolution video signal is encoded in a base layer encoder similar to encoder 12. The original temporal resolution video signal, and a low fidelity decoded base layer video signal are inputted to an enhancement layer encoder. The decoded reference pictures of the low fidelity decoded base layer video signal are used in addition to the decoded pictures of the enhancement layer compressed video signal for forming predictions.
Each of the scalability layers has been proposed for purposes of providing two levels of resolution or quality using the same bitstream. Base layer decoders can only decode the base layer compressed video signal to produce a lower fidelity decoded base layer video signal. Enhancement layer decoders can decode the base and enhanced layer compressed video signals to produce an enhanced fidelity decoded enhancement layer video signal. Nevertheless, both a base layer decoder and an enhancement layer decoder can decode the same bitstream.
It is desirable to use a computer as a video communication terminal. Low cost cameras are available which can produce high quality color and monochrome digital video. The problem is that the bit rate of such digital video signals far exceeds the maximum data input bit rate of any port on a common personal computer. Conventional solutions to this problem include using a camera with a proprietary interface and video capture card that is connected to the computer bus.
U.S. patent application Ser. Nos. 08/708,388 and 08/792,683 propose alternative solutions. These applications propose a camera with a built in encoder, or an encoder adaptor for a conventional video camera. The camera with encoder, or encoder adaptor have an interface that is compliant with the Universal Serial Bus (USB) standard. See Open HCI, Universal Serial Bus Specification v.1.0 Jan. 19, 1996. FIG. 4 shows a system 100 is shown with both types of camera attachment architectures. Illustratively, the system 100 can be used in a real-time, interactive moving picture communication application, a real-time non-interactive picture communication application, a still or moving picture capture application, etc. As shown, a camera 110 is connected to a computer system 120 externally to the housing 156 of the computer system 120. The computer system 120 illustratively includes a cpu bus 122, a system bus 124 (e.g., a PCI bus) and an I/O expansion bus 126 (e.g., as ISA bus). Connected to the cpu bus 122 is at least one processor 128 and a "north" bridge or memory controller 130. The north bridge 130 connects a cache 132 and a main memory 134 to the processors 128 on the cpu bus 122. The north bridge 130 also enables data transfers between devices on the system bus 124 and the memories 132 and 134 or the processors 128. Also connected to the system bus 124 is a graphics adapter 136. A display monitor 138 may be connected to the graphics adapter 136. As shown, an Ethernet adapter 160 may be connected to the system bus 124.
Connected to the I/O expansion bus 126 is a disk memory 140 and interface, such as an IDE interface, a modem 158, and input devices 142 such as keyboard 144 and mouse 146. (Alternatively, the keyboard 144 and mouse 146 may also be connected to the USB hub 150.) Also connected between the system bus 124 and the I/O expansion bus 126 is a south bridge 148 or I/O bridge. The south bridge 148 enables data transfers between devices on the I/O expansion bus 126, such as modem 158, and devices on the USB 200 or devices on the system bus 124. Illustratively, according to the invention, the south bridge 148 also includes a USB hub 150. The USB hub 150 has one or more serial ports 152 that are connected to standard USB compliant connectors 154 to which a connection may be made totally externally to the housing 156 of the computer system. Illustratively, the USB hubs 150, 117, 168, 190 and cables 119 form the USB bus 200.
The camera 110 is shown as including an imaging device 111, such as a tube, CMOS photo sensor or CCD, on which video images are incident. The imaging device 111 converts the image to a motion picture video signal representative thereof. The video signal is converted to digital form in ADC 113. The digital signal outputted from ADC 113 is received at a bit rate reduction circuit 115. The bit-rate reduction circuit 115 may be a programmable frame rate/resolution reduction circuit. Advantageously, however, the bit rate reduction circuit is a programmable video encoder. The bit rate reduced video signal is outputted to a USB hub circuit 117. The USB hub circuit 117 has a serial port 118 that can output the video signal as a serial bitstream via cable 119). The cable 119, which is plugged into the connector 154 (externally to the computer housing 156), delivers the video signal to the serial port 152 of the hub circuit 150 in the south bridge 148.
The reduction of the bit rate by the video encoder 115 ensures that the video signal has a sufficiently low enough bandwidth to be received by the USB serial port 152. Various compression standards such as MPEG-1, MPEG-2, H.263, etc. may be used by the bit rate reduction circuit 115 to encode the video signal.
Note that the USB 200, in particular, the serial ports 118 and 154 of the hubs 150, 117, 168 support bidirectional transfer of signals. In addition to transferring video signals from the hub 117 to the hub 150, data may be transferred from the hub 150 to the hub 117 by interspersing the video signal and the data transfer signal. Such data transfers can be used to program/adjust the video encoder 115. For example, the video encoder 115 can be programmed to encode the video in compliance with a number of compression standards such as, H.263, MPEG-1, MPEG-2, JPEG, motion JPEG, etc. Furthermore, within any given standard, different parameters may be adjusted such as quantization step sizes, inter/intra decision thresholds, group of picture formats, bit rate, etc and different encoding options, such as arithmetic coding, may be selected.
Advantageously, a microphone 162 receives an audible sound and converts it to an audio signal in real time as the camera 110 receives an image. An ADC 164 digitizes the audio signal and an audio encoder 166 encodes the audio signal. Illustratively, a USB hub circuit 168 receives the compressed audio signal and transmits it in bit serial form from serial port 170 to the hub 117, interspersed with the video signal outputted from the camera 110 and any other data signal transmitted on the USB 200.
The hub 150 receives the bit rate reduced video (and illustratively the compressed audio signal). The received signals may be transferred via south bridge 148, system bus 124, and north bridge 130 into one of the memories 132 or 134. From there, the video and/or audio signal may be processed by the processor 128, e.g., error protected using an error protection code, encoded, if necessary, etc. The video and/or audio signal may then be outputted (in multiplexed form) via north bridge 130, system bus 124, Ethernet adapter 160 and an ethernet network to a far end, remote video conferencing system 100' of similar architecture as the video conferencing system 100 (i.e., having a computer system 120' and camera 110'). Alternatively, or in addition, the compressed video and/or compressed audio signals can be outputted via north bridge 130, system bus 124, south bridge 148, I/O expansion bus 126, modem 158 and a public telephone network to the far end, remote video conferencing system 100'. In another embodiment, the compressed video and/or compressed audio signals received at the hub 150 are outputted directly to the Ethernet adapter 160 or modem 158, both of which can be connected to the USB 200.
A compressed video and/or compressed audio signal may be received from the far end, remote video conferencing system 100' at the near end, local video conferencing system 100 shown in FIG. 4. The compressed video and/or compressed audio signals may be received at the Ethernet adapter 160 or at the modem 158. A compressed video and/or compressed audio signal received at the Ethernet adapter 160 may be transferred via system bus 124 and north bridge 130 to main memory 132 or cache memory 134. Alternatively, if the compressed video and compressed audio signals are received at the modem 158, the compressed video and compressed audio signals are transferred via the I/O expansion bus 126, south bridge 148, system bus 124 and north bridge 130 to the memory 132 or 134. From there, the processor 128 may separate the compressed video and compressed audio signals for further processing such as error correction, decryption, and decoding. Alternatively, a special purpose processor (not shown) may be connected to the system bus 124 for performing at least the video signal decoding. In yet another embodiment, a special processor for performing video decoding may be included with the graphics adapter 136 to which the compressed video signal is directly transferred (i.e., from the modern 158 or Ethernet adapter 160). The decoded video signal is transferred to the graphics adapter 136 (or is present thereat). The graphics adapter 136 outputs the decoded video signal on the display monitor 138. In addition, the decoded audio signal is also received via the graphics adapter 136 and outputted to a loudspeaker contained in the display monitor 138.
In the alternative digital video capture embodiment, a digital or analog video signal produced by a camera 110" is outputted to an adaptor 180. The adaptor 180 has a video encoder 195 with a built in USB hub 190. The USB hub 190 is part of the USB 200. The video encoder 195 encodes a digital version of the received video signal in an analogous fashion as above, and transfers the compressed video signal via the (USB hub 190) and USB 200 to the computer system 200.
The system 100 therefore provides an economical and useful manner for providing video communications on a personal computer system 120. In a typical home or business, the communicating systems 100 and 100' typically use modems and the telephone network to communicate. Recent advances enable duplex communication of up to 33.6 Kbits/sec using an ordinary voice connection, assuming that a "clean" (i.e., low noise) circuit is established between the systems 100 and 100' and both systems 100 and 100' have compliant modems with such capability. Sometimes, a single ISDN connection is used to carry the video conference, thereby affording up to 128 Kbits/sec for each communication.
At such low bit rates, a high level of compression is needed to produce a real-time, low latency compressed moving picture video signal. Moving pictures decoded from such compressed video signals have a. large amount of humanly perceptible compression artifacts. Such artifacts degrade the video signal and lower its quality.
In addition to presenting (displaying) at the local system 100 decoded pictures of the remotely originating compressed video signal, it is also desirable to present decoded pictures of the locally originating video signal. For example, the display screen of the display monitor 138 may be divided into two areas or may display two windows. The first window or area displays pictures decoded from the remotely originating compressed video signal. The second window or area displays pictures decoded from the locally originating compressed video signal (which locally originating compressed video signal is also transmitted to the remote system 100'). The problem is that the displayed pictures of the locally originating compressed video signal are reconstructed from the very same locally compressed video signal that is transmitted to the remote system 100'. As noted above, the communication channel over which the locally originating compressed video signal is transmitted has a limited bandwidth. As a result, the locally originating compressed video signal must be highly compressed so that fidelity degrading compression artifacts are introduced into the reconstructed pictures. While such compression artifacts (in the pictures reconstructed from the locally originating compressed video signal) must be tolerated at the remote system 100' considering the bandwidth limitations of the communication channel from which the locally originating compressed video signal is received, such channel bandwidth constraints do not exist at the local system 100 vis-a-vis the locally originating compressed video signal. Thus, such degradations in fidelity of locally displayed pictures reconstructed from locally originating compressed video at the local system 100 are disadvantageous and unnecessary.
It is an object of the present invention to overcome the disadvantages of the prior art.

Dual compressed video bitstream camera for universal serial bus connection


A laser. The novel laser includes a gain medium, a pump source adapted to optically excite the gain medium in a first location, and a resonator adapted to extract energy from the gain medium in a second location distinct from the first location. In an illustrative embodiment, the gain medium is comprised of a plurality of solid-state gain particles suspended in a fluid. The gain medium is adapted to flow, and optical excitation of the gain medium occurs outside of the resonator. In a preferred embodiment, the flow velocity and the density of gain particles in the gain medium are adjusted for optimal absorption efficiency during optical excitation and then for optimal extraction efficiency in the resonator. In addition, the resonator may be shaped for optimal extraction efficiency, while pump modules that hold the gain medium during optical excitation are shaped for optimal absorption efficiency.

1. Field of the Invention
The present invention relates to optical systems. More specifically, the present invention relates to solid-state lasers.
2. Description of the Related Art
Weapon-class lasers are required to have the highest possible power per weight ratio in order to fulfill requirements for a variety of airborne and ground tactical applications. The implementation of a high-energy weapon-class laser system is currently limited to large platforms due to the relatively low power per weight ratio numbers in the present approaches.
Prior attempts to implement a weapons class laser range from the chemical laser to the diode-pumped solid-state power oscillator (PO). The chemical laser is a highly complex system and typically takes up a good portion of the available real estate in an aircraft. In addition, the chemical handling makes this an extremely cumbersome and undesirable approach. The relatively clean diode-pumped solid-state laser approach is much more desirable.
Solid-state lasers, however, have their share of problems. These devices typically require active (or passive) phase conjugation techniques to compensate for high beam distortion generated as the laser propagates through the amplifier chain. In addition, the gain elements themselves are currently comprised of complex, composite slabs that are very expensive and prone to damage. Large size solid-state laser active media are required for power/energy scaling of laser systems, but such media is difficult to fabricate. The number of potential materials for the gain medium is also reduced, since some materials cannot be grown to the sizes needed for a high-energy laser. Furthermore, the large size of the gain medium makes it harder for thermal management to extract heat out of the medium. The large gain medium also makes it more difficult to control optical uniformity, making it harder to control laser beam quality. Finally, the MOPA approach limits the ultimate optical (and, therefore, the overall) conversion efficiency, which results in increased power and wastes heat extraction real estate.
One high-energy solid-state PO laser is the multiple disk heat capacity laser. This laser uses multiple disks of smaller size gain media instead of a single, large bulk medium. Thermal management, however, remains a problem for this approach. The laser can only operate for a few seconds before it needs to be cooled. The smaller gain media disks are faster to cool than a single bulk medium, but several minutes could still be needed for cooling before the laser can be reactivated. In addition, pumping for the multiple disk laser can be difficult to arrange.
Another solid-state approach is the fiber laser. Fiber lasers have inherently high efficiencies because they allow for 100% pump power absorption and operate at very high laser intensity, and can be cooled efficiently due to their inherently high surface to volume ratio. Fiber lasers, however, are ultimately limited by the maximum power at which they can operate due to intensity damage threshold limits. In order to generate higher powers, several fibers need to be combined. This, however, requires phasing of multiple fiber oscillators, which adds a number of problems (not satisfactorily solved yet) and associated complexities.
Hence, a need exists in the art for an improved solid-state laser that is scalable for high energy and power, and that offers better optical quality, easier fabrication, and improved thermal management than conventional approaches.

Solid-state suspension laser with separate excitation and extraction


The present invention intends to provide a laser corneal surgery apparatus in which an optical system for directing and irradiating a laser beam onto a cornea can be protected from water droplets and the like. The laser corneal surgery apparatus for ablating a cornea of a patient's eye by a laser beam comprises an observation optical system for observing the patient's eye, an irradiation optical system for irradiating the laser beam onto the cornea, and a protection plate which is disposed on an irradiation optical path between the cornea and an optical member included in the irradiation optical system and disposed in a position nearest to the cornea, and which is insertable in and removable from the optical path.

1. Field of the Invention
The present invention relates to a laser corneal surgery apparatus for ablating a cornea of a patient's eye by a laser beam for the purpose of correcting a refractive error and the like.
2. Description of Related Art
As keratorefractive surgery using an excimer laser beam which is ultraviolet light, laser assisted in-situ keratomileusis (LASIK) is performed, in which a flap is formed by incising the part from an epithelium to a stroma in layered form, the stroma is ablated (removed) by irradiating a laser beam, then the flap is returned.
A corneal incision apparatus called a microkeratome is used for forming a flap. As disclosed in European Patent Application Publication No. 956840 A2 corresponding to Japanese Patent Application Unexamined Publication No. HEI 11-342151, such an apparatus has been known that a corneal pressing member presses the corneal part projecting from an opening of a suction part sucking and being fixed on a corneal surface so that the projecting part is flattened, then a blade is transversely oscillated and moved straight or rotatably moved to incise the epithelium.
When a surgical operator uses the corneal incision apparatus described above, he may confirm operations of a blade drive using a microscope included in the laser corneal ablation apparatus. In this case, since water (physiological saline) is used as a lubricant to the blade, a spray of water forms, whereby water droplets may adhere to an optical member (a mirror or lens) placed nearest to the cornea to be irradiated in the optical system for guiding and irradiating the excimer laser beam onto the cornea. In general, a coating of a mirror reflecting ultraviolet light is water-sensitive, and adhesion of the water droplets affects the laser irradiation. Further, since water is used for preventing the cornea from getting dry during corneal incision, water droplets generated incident to the blade drive of the corneal incision apparatus may adhere to the optical member nearest to the cornea.


Image data are inputted from a data processing means (23) into storage means (24) so that light emitting elements on one line (28a) of a light emitting element (yellow) line head (28) are actuated according to signal outputted from a shift resistor (24a) so as to expose pixels on an image carrier. At a point of time when the pixels reach a position corresponding to the light emitting elements in a next line (28b) by moving the image carrier in a direction of arrow X, the image data are transmitted to a shift resistor (24b) and then outputted to the line (28b) so as to expose the pixels again. The image data are transmitted among the shift resistors sequentially by moving the image carrier, thereby achieving the multiple exposure of the same pixels.

In conventional image forming apparatus in which a latent image is written on an image carrier, it is known to employ an LED (light emitting diode) array as writing means. In case of employing light emitting elements such as an LED, it is necessary to pay attention to the relation between the luminance (amount of light) and the life duration of each light emitting element. That is, the life duration can be increased by reducing the luminance of the light emitting element. In this case, however, there is a problem that the amount of light for exposure is insufficient to form image. When the luminance of the light emitting element is increased, enough amount of light for exposure for forming image is obtained. In this case, however, there is a problem that the life duration is shortened.
For this, the development of material for obtaining light emitting elements capable of providing large luminance and having long life duration has been encouraged. However, in the present state of affairs, it is too expensive to achieve the practical use. In this connection, a line head (optical head) of multiple exposure type in which each pixel is exposed by a plurality of light emitting elements has been developed. As an example (1) of such line heads of multiple exposure type, Japanese Patent Unexamined Publication No. S61-182966 discloses a recording array head on which light recording elements are aligned in a plurality of rows in the rotational direction of a photoreceptor drum. An image data is overlappingly recorded at the same pixel by shifting the light emitting recording elements in the direction of the rows with moving the photoreceptor drum. The example (1) has an advantage that higher speed image formation is achieved even using light recording elements with low light-emitting output.
Another example (2) is disclosed in Japanese Patent Unexamined Publication No. S64-26468 in which an EL element panel is composed of EL element group of 20 dots×640 dots (vertical×horizontal). The EL element group is driven at a speed same as the moving speed of a photoreceptor for every line. Accordingly, the amount of light irradiated on a single pixel is twentyfold the amount of light emitted from each EL element. This example also can cope with high speed of image formation because the amount of light of exposure per pixel is increased.
Another example (3) is disclosed in Japanese Patent Unexamined Publication No. H11-129541 and is a print head on which LEDs are aligned in a plurality of lines such that multiple exposure is made on each pixel by moving the print head in the main scanning direction. In this example, since the multiple exposure is conducted, variations in amount of light among the respective LEDs can be equalized, thereby improving the image quality. Still another example (4) is disclosed in Japanese Patent Unexamined Publication No. 2001-260411 and is an optical printer head on which plural lines of LED array chips are aligned. The gradation of each pixel can be changed among three levels by turning ON or OFF the LED array chips on each line.
The aforementioned examples (1) and (2) relate to a technology of monochrome image formation and therefore have a problem that gradation control for neutral density is impossible. The example (3) relates to a technology of a serial type in which the line head is driven and therefore has a problem of having a complex driving mechanism. The example (4) relates to a technology in which the LED array chips on each line are turned ON and OFF and therefore has a problem of complexity of the control circuit.
Since the number of light emitting elements in the line head of multiple exposure type are greater than that of a line head of normal exposure type and it is necessary to control the light emitting elements synchronously with the movement of the photoreceptor, there is a problem of complexity of the control circuit for conducting the data processing and it is therefore difficult to achieve higher speed light emitting control. Especially, in case that a line head (optical head) of multi-exposure type is employed for color image formation, the amount of data to be processed must be several fold that in the case of ON-OFF control because the gradation control for each pixel is sometimes required. This makes the speeding up of emission control further difficult. In case of line head of multiple exposure type, it is required to send a large amount of data processed by a data processing unit to the line head, thus increasing the number of wires between the line head and the body of an image forming apparatus. Accordingly, it is necessary to employ an interface capable of supporting the high-speed processing, thus increasing the cost.
The present invention was made in view of the aforementioned problems of conventional techniques and the object of the present invention is to provide an image forming apparatus and an image forming method which are directed to simplify the circuit structure and to speed up the light emitting control during the exposure of pixels on an image carrier in multiple exposure manner capable of outputting gradation.

Image forming apparatus and image forming method


A computer-implemented method for securing storage space may include 1) identifying a block map that indicates whether each of a plurality of blocks within a storage system is to return zeroed data in response to read operations, 2) identifying a read operation directed to a block of the storage system that includes non-zeroed data, 3) determining, in response to identifying the read operation, that the block map indicates that the block is to return zeroed data in response to the read operation, and 4) returning zeroed data in response to the read operation based on determining that the block map indicates that the block is to return zeroed data. Various other methods, systems, and computer-readable media are also described.

Consumers and organizations increasingly rely on digitally-stored data. As the cost of digital data storage decreases and the reliance on digitally-stored data increases, file systems may manage ever greater amounts of data. These file systems may allocate and/or deallocate storage space from storage systems as needed.
Because the same storage space can be reused over time (e.g., deallocated after a prior use and reallocated for a new use), some allocation schemes may allow access to old data (e.g., meant to have been deleted) through new allocations. For example, when a file is deleted from a file system, the storage blocks underlying the file may be deallocated from the file, but the contents of the storage blocks may remain intact. Subsequently, one or more of these storage blocks may be pre-allocated to a new file of a predetermined size. Unfortunately, in some cases this data may be sensitive. Even though access to the original file may have been restricted, the sensitive data may become accessible via the newly pre-allocated file.
Some traditional file systems may attempt to prevent such data leaks by overwriting pre-allocated storage blocks (e.g., with zeroed data). Unfortunately, overwriting the pre-allocated storage blocks may be time- and resource-intensive, especially in the case of pre-allocating storage blocks for very large files. Furthermore, future read operations directed to these files may consume significant computing resources. Accordingly, the instant disclosure identifies and addresses a need for additional and improved systems and methods for securing storage space.

Systems and methods for securing storage space


A counterbalance system (25) for a door (D) movable between a closed position and an open position having an axle (20), a cable drum (15) attached to the axle, a winding shaft (35) interconnected with the axle by a counterbalance spring (26), and a pawl (70) selectively movable between a first position for adjusting tension in the counterbalance spring and a second position for preventing rotation of the cable drum upon failure of the counterbalance spring, thereby limiting movement of the door toward the closed position.

Most sectional doors employ a track system that guides the door panels from a closed generally vertical position to an open generally horizontal position. Sectional doors normally employ a counterbalance system having a spring to counteract the weight of the door. Optimally, the counterbalance spring would have sufficient tension, such that the door would fully close and only a small amount of force would be necessary to raise the door from the closed position. Counterbalancing springs can be either extension springs or torsion springs. Torsion spring counterbalance systems normally have an axle to distribute the torsional force from the counterbalance spring or springs equally to the door through cable storage drums and cables attached thereto. The counterbalance springs can either be enclosed within the axle or placed outside an axle. The counterbalance springs are pre-tensioned during installation.
Safety considerations dictate the need for a device that prevents the door from falling in the event of eventual failure of one of the components of the counterbalance system, for example, the rupture of the counterbalance spring. Failure of the counterbalance spring while the door is partially open can result in the unexpected and uncontrolled closure of the door. This may cause inconvenience to the user, as well as present safety concerns to anyone located underneath the door at the moment of spring failure. Consequently anti-drop assemblies have been developed that, upon failure of the counterbalance assembly, stop or at least slow descent of the door.
One type of anti-drop mechanism senses loss of tension in the counterbalance cable. The counterbalance cable attaches to the cable drum which, using force of the counterbalance spring and a driving force, raises the door to the upright position. If during operation the cable breaks, the cable in turn loses tension. An example of this type of anti-drop mechanism has a pawl that engages the cable during normal operation, and upon loss in tension, a bias member overcomes any remaining cable tension and pushes the pawl into contact with a stop surface to stop descent of the door. This mechanism is effective against cable breaks but does not protect against counterbalance spring failure.
In another type of anti-drop system, centrifugal force is used to brake the door upon counterbalance spring failure. Typically such systems include a stator, a rotor and a stop dog held in place by bias elements. If the counterbalance spring breaks, the door drops at speeds that are faster than normal operation. As the rotor spins, the centrifugal force overcomes the bias force and moves the stop dog into contact with the stator, thereby stopping the rotor. The reaction speed of these systems is slower than other safety systems, allowing the door to fall further and thereby increase the chance of damage or injury. Further, stronger components are normally needed for such systems, increasing the cost and complexity of the door control components.
Various other anti-drop systems employ arrangements where a counterbalance spring or its axle is attached to a ratchet wheel or a pawl such that upon loss of spring tension the pawl engages the ratchet wheel to lock the mechanism that effects raising and lowering of the door or other barrier. These systems are typically relatively complex in terms of the number and design of the component parts. Further, this complexity and the probability of deterioration or corrosion over years in an inoperative status makes operation of the system problematic when the counterbalance spring normally fails. In addition, many of these anti-drop systems are limited by their design to utilization with counterbalance systems wherein the torsion springs are mounted outside the axle.

winding and anti-drop assembly for door counterbalance system


The invention relates to optical communications using techniques for providing efficient high speed polarization bit interleaving. One common architecture for high-speed time-division-multiplexing employs two modulators having a same bit rate, wherein two separately modulated streams of data bits are combined into a high-speed single serial stream of data bits, instead of providing a single higher-cost higher-speed modulator. The present invention has found with the availability of fast data modulators, that polarization bit interleaving can be employed more efficiently for higher speed data transmission in optical network systems by providing an optical modulator including a single data modulator, rather than multiplexing different data streams from different modulators. The present invention provides an optical modulator for encoding data on orthogonally polarized alternate light pulses comprising: means for modifying a laser light beam to a pulse train at a first frequency; a data modulator for encoding signal data on the pulse train at a second data stream frequency where the second frequency is greater than or equal to the first frequency; means for rotating a polarization state of at least alternate light pulses of the pulse train to provide a data stream of orthogonally polarized alternate light pulses.

High-speed time-division-multiplexing (TDM) is a very attractive way of enhancing the spectrum efficiency of a large-capacity wavelength-division multiplexing (WDM) system. One common architecture employs two modulators having a same bit rate, wherein two separately modulated streams of data bits are combined into a high-speed single serial stream of data bits. Instead of providing a single higher-cost higher-speed modulator capable of providing modulation at a frequency of n Hz, two modulators having a frequency of n/2 Hz are provided and their outputs are time-interleaved providing a signal having a frequency of n Hz. However, one drawback to such a scheme, particularly in high-speed dense systems is that pulses from adjacent time slots spread and partially overlap one another and detection errors sometimes occur at a receiver end.
One remedy for this is provided by an enhanced TDM system wherein adjacent interleaved pulses are distinguishable as they are orthogonally polarized. Such a scheme is described in a paper entitled 1.04-Tbit/s SWDM Transmission Experiment Based on Alternate-Polarization 80-Gbit/s OTDM Signals, by Yutaka Miyamoto et al., published in ECOC'98 20–24 September 1998 Madrid, Spain. In this paper alternate-polarization optical-TDM is described to increase the bit rate while keeping the signal spectrum from broadening. Here two modulated signals are time-division multiplexed with additional enhancement being achieved by polarization multiplexing of the two interleaved TDM streams.
Another system using enhanced polarization optical TDM is described and illustrated in U.S. Pat. No. 5,111,322 in the name of Bergano et al, entitled Polarization Multiplexing Device with Solitons and Method Using Same, incorporated herein by reference. In this patent, a transmission system's capacity is increased by using a combination of polarization and time-division multiplexing. More specifically, two streams of differently (preferably orthogonally) polarized solitons are interleaved (time-division-multiplexed) at a transmitter, and later separated at the receiver to recover both data streams.
Fast modulators (eg. 40 Gbit/s), with a potential of up to double this rate) are also available instead of time division multiplexing signals from two slower modulators. However, problems of pulse broadening and jitter in a high speed pulse stream cause the pulses to begin to overlap and act coherently causing non-linear interactions and interference with the result that the signal cannot travel as far with an acceptable error rate as slower bit rate systems. Polarization multiplexing, as disclosed in U.S. Pat. No. 5,111,322 prevents the non-linear interactions. Since the alternately polarized pulses cannot interact, the signal can travel farther at the same bit error rate. The method of providing the polarization multiplexing taught by Bergano, however, is difficult to realize.
The Bergano device, shown in prior art FIG. 1, provides a mode locked laser light source 201 which outputs a train of pulses at a pulse repetition frequency of, for example, 2.5 GHz, ie. half the desired rate of the output signal. The pulse train is then split by a polarization beam splitter 202 into two beams of equal amplitude having orthogonal polarization. Each beam travels through a data modulator 205,206 operating at the 2.5 Gbit/s rate. A delay line (not shown) is needed to ensure that the pulses in the two beams arrive at the two modulators 205,206 simultaneously. At the same time, the RF signals for both modulators also need to be synchronized with the pulses. At 2.5 Gbit/s this synchronization is not such a difficult problem as for a 40 Gbit/s system or faster. As further taught by Bergano, polarization controllers 211–214 are required to maintain the required linear polarizations. After passing through the data modulators 205,206, one of the pulse trains is delayed at delay line 209 by half of the period enabling the two orthogonally polarized beams to be recombined at the polarization splitter 210 providing a signal output at 5 Gb/s.
The use of two data modulators, in Bergano, and two associated drivers makes this system expensive and rather complex. Two broad band modulators, and two associated data drivers are required. The optical pulses in the two arms need to be synchronized with sub-picosecond accuracy to arrive at the modulators at precisely the same time. A further problem of electrical cross talk occurs between the two modulators, particularly in an integrated design. The mode locked laser has a modulation which must also be synchronized with the data modulators. This synchronization is somewhat more difficult. In addition, the RF data needs to be synchronized with the optical pulse trains with the same precision. This requires at least one, but usually two electrical delay lines. In addition, the powers in the two arms need to be equalized, usually requiring a variable optical attenuator in each arm.
It is desired to provide a simple and economical device and method for providing polarization bit interleaving using a single data modulator.

Optical modulator and method for polarization bit interleaving


Disclosed are a light modulation apparatus including a liquid crystal device; and a polarizing plate disposed in an optical path of light made incident on said liquid crystal device; wherein said liquid crystal device is of a guest-host type using a negative type liquid crystal as a host material, an image pickup apparatus using the light modulation apparatus, and methods of driving the light modulation apparatus and image pickup apparatus.

The present invention relates to a light modulation apparatus for modulating the quantity of incident light and outputting the modulated light and an image pickup apparatus using the light modulation apparatus, and methods of driving the light modulation apparatus and the image pickup apparatus.
Light modulation apparatuses have been known of a type including a liquid crustal cell, typically, a twisted nematic (TN) type liquid crystal cell or a guest host type liquid crystal cell (GH cell), and a polarizing plate.
FIGS. 1A and 1B are schematic views showing an operational principal of a related art light modulation apparatus mainly including a polarizing plate 1 and a GH cell 2, and FIG. 1C is a graph showing a rectangular waveform of a drive voltage to be applied to the GH cell 2. In the figures, for ease of description, components of a liquid crystal device other than the GH cell 2, for example, two glass substrates between which the GH cell 2 is held, operational electrodes, and liquid crystal alignment films formed on the substrates are omitted. The GH cell 2 contains liquid crystal molecules 3 and dichroic dye molecules 4. The dichroic dye molecules 4 have a positive type (p-type) light absorption anisotropy capable of absorbing light in the alignment direction of major axes of the molecules, and the liquid crystal molecules 3 have a positive type (p-type) dielectric constant anisotropy.
FIG. 1A shows a state of the GH cell 2 when no voltage is applied thereto. Incident light 5, which passes through the polarizing plate 1, is linearly polarized by the polarizing plate 1. In this related art light modulation apparatus, since the polarization direction of the linearly polarized light corresponds to the alignment direction of the major axes of the dichroic dye molecules 4, the light is absorbed in the dichroic dye molecules 4, with a result that the transmittance of the GH cell 2 is reduced.
When a voltage having a rectangular waveform shown in FIG. 1C is applied to the GH cell 2 as shown in FIG. 1B, the alignment direction of the major axes of the dichroic dye molecules 4 becomes perpendicular to the polarization direction of the linearly polarized light, with a result that the light is little absorbed in the GH cell 2, that is, most of the light passes through the GH cell 2.
In the case of using a GH cell including a negative type (n-type) dichroic dye molecules capable of absorbing light in the alignment direction of minor axes of the molecules, the relationship between light absorption and light transmission of the GH cell is reversed to that of the GH cell 2 including the positive type dichroic dye molecules 4. To be more specific, the light is not absorbed in the GH cell including the negative type dichroic dye molecules when no voltage is applied thereto, and light is absorbed in the GH cell including the negative type dichroic dye molecules when a voltage is applied thereto.
An optical density (absorbance) ratio of the light modulation apparatus shown in FIGS. 1A to 1C, that is, a ratio of an optical density of the apparatus upon application of a voltage to an optical density thereof upon application of no voltage is about 10. This optical density ratio of the apparatus shown in the figures is as large as about twice an optical density ratio of a light modulation apparatus including only the GH cell 2 without use of the polarizing plate 1.
The related art light modulation apparatus shown in the figures has a problem. Since the polarizing plate 1 is fixed in an effective optical path of light, part of light, for example, 50% of light is usually absorbed in the polarizing plate 1, and further light may be reflected from the surface of the polarizing plate 1. As a result, the maximum transmittance of light passing through the polarizing plate 1 cannot exceed a certain value, for example, 50%, and accordingly, the quantity of light passing through the light modulation apparatus is significantly reduced by light absorption of the polarizing plate 1. This problem is one of factors which make it difficult to put a light modulation apparatus using a liquid crystal cell into practical use.
On the other hand, various kinds of light modulation apparatuses using no polarizing plate have been proposed. Examples of these apparatuses include a type using a stack of two GH cells in which the GH cell at the first layer absorbs a polarization component in the direction identical to that of polarized light and the GH cell at the second layer absorbs a polarization component in the direction perpendicular to the polarized light; a type making use of a phase transition between a cholesteric phase and a nematic phase of a liquid crystal cell; and a high polymer scattering type making use of scattering of liquid crystal.
These light modulation apparatuses using no polarizing plate have a problem. Since the optical density (absorbance) ratio between upon application of no voltage and upon application of a voltage is, as described above, as small as only 5, the contrast ratio of the apparatus is to small to normally carry out modulation of light at any location in a wide range from a bright location to a dark location. The light modulation apparatus of the high polymer scattering type has another problem in significantly degrading, when the apparatus is used for an image pickup apparatus, the image formation performance of an optical system of the image pickup apparatus.
The related art light modulation apparatus presents a further problem. Since the transmittance in a transparent state may become dark depending on the kind of a liquid crystal device used for the apparatus, if an image pickup apparatus provided with the light modulation apparatus is intended to pickup image with a sufficient light quantity in such a transparent state, the light modulation apparatus is required to be removed from an optical system of the image pickup apparatus.
The related art light modulation apparatus has the following problem associated with the drive thereof. To drive the related art light modulation apparatus, the transmittance has been controlled by modulating a magnitude of a DC voltage or AC voltage applied to the apparatus; however, for the light modulation apparatus at a consumer level, it is difficult to accurately perform voltage control and to obtain a characteristic having a low threshold value; a limitation lies in the number of gradation of the transmittance level; and D/A conversion is required for voltage control based on the intensity of transmission light, to raise a circuit cost.
The drive of the related art light modulation apparatus, particularly, of a type including a negative type liquid crystal having a negative dielectric constant anisotropy has another problem. In the related art light modulation apparatus, the transmittance has been changed with a large step from a current transmittance into a target transmittance; however, upon such a change in transmittance with a large step, particularly, from a transmittance in a transparent state into a transmittance in a light shield state, there occurs a defect in alignment of liquid crystal molecules, resulting in unstable optical characteristics, for example, in-plane non-uniformity in transmittance (which will be described later).
To be more specific, when a voltage applied to the liquid crystal is changed with a large step for changing the transmittance with a large step, there occurs a transient state in which liquid crystal molecules are aligned in different directions, and if such a transient state continues for a time being long enough to exert an effect on the transmittance, there appears in-plane non-uniformity in transmittance. In general, the transient state disappears after an elapse of a certain time required for re-alignment of liquid crystal molecules and pigment molecules; however, in the worst case, the transient state may partially remain even after an elapse of a long time.
A further problem of the drive of the related art light modulation apparatus is that even in a state in which drive pulses with a specific control waveform are applied to a liquid crystal device of the light modulation apparatus, there occurs a variation in transmittance due to a change in temperature of the environment in which the apparatus is disposed.

Light modulation apparatus, image pickup apparatus, and drive methods therefor


An apparatus is provided for mechanically attaching an optical fiber to a substrate. The apparatus includes a clamping block formed of malleable material disposed adjacent a substrate. The fiber is disposed adjacent the clamping block and a securing member such as a fastener or spring is used to secure the fiber to the clamping block and substrate. The frictional forces between the fiber and the clamping block eliminate movement of the fiber relative to the substrate.

1. Technical Field
The present invention generally relates to alignment, positioning, attachment and connection of optical fibers to other components and more specifically to devices incorporating fiber bragg gratings.
2. Discussion
A fiber bragg grating device consists of an optical fiber having a periodic stack of regions with higher and lower refractive indexes. With this configuration, light within a narrow band of wavelengths is reflected while all wavelengths outside that band are transmitted. One critical aspect of fiber bragg grating devices is the period at which the higher and lower refractive index regions change with temperature.
Conventional bragg grating devices compensate for thermal drift and refractive index changes by mounting the fiber under tension on a negative thermal expansion substrate. The fiber is mounted to the substrate by way of a glass frit. Glass frits are advantageous since they exhibit little or no creep. However, glass frits also have certain drawbacks.
For example, a significant problem associated with glass frits results from the high temperatures required for attachment. That is, cooling of the frit results in large stresses on the assembly due to the thermal expansion mismatch between the frit, fiber, and substrate. Additionally, high temperatures have been shown to degrade certain types of negative expansion substrates, cause CWL drift, grating fade, and decrease fiber tensile strength.
One theory for overcoming the above-identified problems is to attach the fiber to the substrate at a temperature near the operating temperature of the assembly such that the effect of the thermal expansion mismatch is minimized. Adhesive polymers have been considered for such use. However, polymers exhibit significant creep which is detrimental to the performance of the fiber bragg grating device.
In view of the foregoing, it would be desirable to provide an apparatus for attaching a fiber to a substrate such as those used in fiber bragg grating devices which overcomes the problems associated with the prior art.
The above and other objects are provided by mechanically attaching the fiber to the substrate such that no chemical bond is made with the fiber and only frictional forces from an applied radial force hold the fiber in place. The mechanical attachment is made at ambient temperatures such that the thermal expansion mismatch of the materials used is not a concern. The apparatus preferably includes a clamping block formed of malleable material disposed adjacent substrate. An optical fiber is disposed adjacent the clamping block and a securing member such as a fastener or spring is used to secure the fiber to the clamping block substrate. The frictional forces between the fiber and the clamping block eliminate movement of the fiber relative to the substrate.

Non-adhesive mechanical fiber connection


Methods and computer programs for determining the top most critical timing paths in an integrated circuit (IC) based on a timing graph of registers and combinational nodes in the IC are provided. One method generates the most critical path to each destination register and invokes a function to calculate the next critical path in each destination register a number of times according to the number of top most critical paths desired. The method uses recursion to calculate critical paths on the different nodes by recursively calling a function to calculate the next critical path on a fan-in node, where the fan-in node corresponds to the node which last contributed a critical path. Further, the most critical path to the node is selected in the recursive function. The critical paths are used to determine if the IC is stable under the analyzed clock frequency.

The present invention relates to calculating critical paths in signal propagation within an integrated circuit (IC). When analyzing a particular IC design, computer tools estimate signal propagation delays throughout the IC in order to determine the maximum operating frequency of the IC. Electric signals reach destination registers through intermediate registers, gates, buffers, etc. Signals may propagate to destination registers through different paths, thus causing the different signals to reach a destination register at different times depending on the signal delay thorough each of the paths.
Timing analysis tools often use timing graphs to analyze signal propagation, such as the propagation delays from source registers to destination registers. A source register is a register that has at least one timing path from itself to another register. A destination register is a register that has at least one timing path arriving from another register. A register can be both a source register and a destination register.
The design engineer is interested in finding out what are the most critical paths in the IC to determine if the application and operating frequency are appropriate for the design. Given the large amounts of registers, gates, buffers, wires, etc., in today's ICs, the calculation of all possible paths requires vast amounts of time and computer resources. It is in this context that embodiments of the invention arise.

Determination of most critical timing paths in digital circuits


Cargo carriers are disclosed, and more particularly adjustable cargo carriers that may be mounted on a rear of a vehicle.

The popularity of recreational cycling has grown substantially in recent years. As a result, the demand for cargo carriers to transport bikes and other types of cargo items on cars and other vehicles also has grown. There are various types of vehicle-mounted cargo carriers available. One type is mountable on the trunk or other rear portion of a vehicle to carry one or more cargo items adjacent the rear of the vehicle. While some rear-mounted carriers are adjustable, the adjustment mechanisms are cumbersome or do not provide sufficient adjustability to mount those carriers on different vehicles and/or to support different cargo items.


A milk substitute composition is prepared with whey solids or whey solids and added lactose by dissolving a whey solids powder in an aqueous medium containing calcium sequestering agent and carrageenate components at a temperature of approximately from 30.degree. C. to 65.degree. C. and then, in a second step, at the same temperature, a skimmed milk solids powder is dissolved in the whey-containing medium, and before and/or after dissolving the skimmed milk solids powder, the whey solids are allowed to soak in the aqueous liquid phase of the composition so prepared for from 10 minutes to 4 hours for hydrating the whey solids. When lactose is used, the amount of whey solids powder employed may be reduced by about half.

The present invention relates to milk products and particularly to preparation of milk products wherein whey is substituted for a portion of milk employed to prepare the products.
The use of whey is known in the manufacture of milk products. The advantage of using whey as a milk substitute is essentially connected with its low cost. However, the use of whey as a replacement for milk is a difficult operation. It is, in point of fact difficult to ensure that the product has thermal stability and good storage life with whey proteins.
European Patent Application Publication No. 0 627 169 concerns a process for processing milk which enables these fixed objectives to be partially achieved. Within the context of this patent application, the product to be processed may be in the form of whole milk, partially skimmed milk, skimmed milk or whey. Processing is carried out by the technique of evaporation. However, there are some disadvantages that this method does have:
Firstly, it is not suitable for obtaining milk reconstituted from milk powder. Consequently, the milk must be processed as near as possible to the milk producer and the consumer in order to reduce transport costs. PA1 Secondly, this processing procedure does not enable sedimentation to be prevented after processing, in particular when the product is sterilized.

Milk substitute prepared with whey or whey and added lactose


A reflective liquid crystal display device includes a first substrate including a display region and a first non-display region, the first non-display region being disposed at a boundary of the display region. A second substrate faces and is spaced apart from the first substrate, the second substrate including a second non-display region corresponding to a portion larger than the first substrate. A light absorption layer is on an inner surface of the first substrate. A cholesteric liquid crystal color filter (CCF) layer is at the display region and the first non-display region is on the light absorption layer. A common electrode is on the CCF layer. An array element is on an inner surface of the second substrate. A light shielding pattern is on the array element, the light shielding pattern corresponding to the CCF layer at the first non-display region. A retardation plate and a polarizing plate are sequentially formed on the outer surface of the second substrate. A liquid crystal layer is interposed between the common electrode and the array element.

1. Field of the Invention
The present invention relates to a liquid crystal display (LCD) device, and more particularly, to a reflective LCD device having a cholesteric liquid crystal (CLC) color filter.
2. Discussion of the Related Art
Presently, LCD devices are developed as next generation display devices because of their light weight, thin profile, and low power consumption characteristics. In general, an LCD device is a non-emissive display device that displays images using a refractive index difference utilizing optical anisotropy properties of liquid crystal material that is interposed between an array (TFT) substrate and a color filter (C/F) substrate. Among the various type of LCD devices commonly used, active matrix LCD (AM-LCD) devices have been developed because of their high resolution and superiority in displaying moving images. The AM-LCD device includes a thin film transistor (TFT) per each pixel region as a switching device, a first electrode for ON/OFF, and a second electrode used for a common electrode.
FIG. 1 is a perspective view of an LCD device according to the related art.
In FIG. 1, first and second substrates 10 and 30 are arranged to face each other with a liquid crystal material layer 50 interposed therebetween. On an inner surface of the first substrate 10, a color filter (C/F) layer 12 and a common electrode 16, which functions as one electrode for applying an electric field to the liquid crystal layer 50, are subsequently formed. The C/F layer 12 includes a color filter for transmitting only light of a specific wavelength, and a black matrix (not shown) that is disposed at a boundary of the color filter and shields light of a region in which alignment of the liquid crystal material is uncontrollable. On an inner surface of the second substrate 30, a plurality of gate lines 32 and a plurality of data lines 34 are formed in a matrix array. A TFT "T", which functions as a switching device, is disposed at a region where each gate line 32 and data line 34 crosses, and a pixel electrode 46 that is connected to the TFT "T" is disposed at a pixel region "P" defined by the region where the gate and data lines 32 and 34 cross. First and second polarizing plates 52 and 54, which transmit only light parallel to a polarizing axis, are disposed on an outer surface of the first and second substrates 10 and 30, respectively. An additional light source such as a backlight, for example, is disposed below the second polarizing plate 54.
The LCD device of FIG. 1 is a transmissive LCD device that displays images by transmitting only desired light through the first substrate using an optic/dielectric anisotropy of the liquid crystal layer after light from the backlight passes through the second substrate.
FIG. 2 is a schematic plan view of an LCD device according to the related art. FIG. 2 shows gate and data pads for connection with an external circuit.
In FIG. 2, a liquid crystal panel 60 for an LCD device includes a first substrate 10, a second substrate 30 larger than the first substrate 10, and a liquid crystal layer 50 interposed between the first and second substrates 10 and 30. The liquid crystal panel 60 can be divided into a display region "D," and first and second non-display regions "N1" and "N2" in plan view. The first non-display region "N1" is defined by the first and second substrates 10 and 30, and the second non-display region "N2" is defined by a larger portion of the second substrate 30. Elements such as a TFT, gate and data lines, a pixel electrode, a color filter layer and a common electrode illustrated in FIG. 1 are formed in the display region "D." Gate and data pads 62 and 64 connected to an external circuit (not shown) are formed in the second non-display region "N2" to apply a display signal to the display region "D." Since a black matrix 66 formed in the first non-display region "N1" of the first substrate 10 absorbs incident light, a boundary of the display region "D" maintains a black state.
FIG. 3 is a schematic cross-sectional view of an LCD device according to the related art. A boundary of a display region is mainly shown in FIG. 3.
In FIG. 3, a boundary of first and second substrates 10 and 30 with a liquid crystal layer 50 therebetween is sealed with a seal pattern 68. A color filter layer 40 on an inner surface of the first substrate 10 is extended to a first non-display region "N1" so that a deterioration at a boundary of a display region "D" by a step difference between the display region "D" and the first non-display region "N1" can be prevented during a rubbing process for aligning the liquid crystal layer 50. Array elements 42 such as a TFT and a pixel electrode (of FIG. 1) are formed on an inner surface of the second substrate 30. When light is emitted into the first non-display region "N1," a black matrix 66 of the first non-display region "N1" absorbs the light. Accordingly, a black state is maintained in the boundary of the display region "D."
Reflective LCD devices without a backlight are being researched and developed. Transflective LCD devices use a backlight to provide light. However, only about 7% of the light that is emitted by the backlight passes through each cell of the LCD device. Since the backlight should emit light of a relatively high brightness, corresponding power consumption increases. Accordingly, a large capacity heavy battery is commonly used to supply sufficient power for the backlight. Moreover, use of the large capacity battery limits operating time. On the other hand, because power consumption of the reflective LCD devices greatly decreases due to use of ambient light as a light source, operating time increases. Such reflective LCD devices are used for portable information apparatuses such as electronic diaries and personal digital assistants (PDAs). In the reflective LCD devices, a pixel area, which is covered with a transparent electrode in conventional transmissive LCD devices, is covered with a reflective plate or reflective electrode having opaque reflection characteristics.
However, brightness of reflective LCD devices is very poor because the devices use only ambient light as a light source. The poor brightness results from operational characteristics of the reflective LCD devices in which ambient light which passes through a color filter substrate, is reflected on a reflective electrode on a second substrate, is passed through the color filter substrate again and then displays an image. Accordingly, brightness is decreased as a result of reduction of the transmittance when the ambient light passes through a color filter layer twice. Since overall thickness of the color filter layer is inversely proportional to transmittance and is directly proportional to color purity of the light, the problem of inadequate brightness of the reflective LCD devices can be remedied by forming a thin color filter layer with high transmittance and low color purity. However, there is a limit in fabricating the color filter layer below a threshold thickness due to characteristics of the resin used to form the color filter layer.
Accordingly, one possible solution to this problem is fabricating LCD devices using cholesteric liquid crystal (CLC) that has selective reflection and transparency characteristics. In reflective LCD devices using a CLC color filter (CCF) layer, the fabrication processes are simplified due to omission of the reflective layer, and high color purity and high contrast ratio are achieved. Moreover, since CLC has a spiral structure and spiral pitch determines a selective reflection bandwidth of the CLC, the reflection bandwidth can be controlled by a distribution of the spiral pitch at one pixel. To illustrate this in more detail, a wavelength range of visible light is from about 400 nm to about 700 nm. The wavelength of the red light region is centered at about 650 nm, the wavelength of the green light region is centered at about 550 nm, and the wavelength of the blue light region is centered at about 450 nm. The CCF layer is formed having characteristics that can selectively reflect or transmit right-handed or left-handed circularly polarized light at a bandwidth that corresponds to a pitch deviation by selecting bandwidths corresponding to the red, green, and blue light regions. In addition, the CCF layer is formed having characteristics that control conditions for right or left pitch deviations with respect to the center wavelength. Accordingly, the pitch of the liquid crystal can be artificially adjusted so that a CCF layer can selectively reflect light of an intrinsic wavelength of the color corresponding to each pixel.
FIG. 4 is a schematic plan view of a reflective LCD device using a CCF layer according to the related art. FIG. 4 shows gate and data pads for connection with an external circuit.
In FIG. 4, since the reflective LCD device using a CCF layer displays images by reflecting ambient light, array elements (not shown) and a CCF layer are formed on first and second substrates 70 and 72, respectively. Accordingly, the first substrate is larger than the second substrate 72. As a result, even though a display region "D" is disposed as in the LCD device of FIG. 3, a first non-display region "N1" corresponds to a boundary of the second substrate 72 and a second non-display region "N2" corresponds to a larger portion of the first substrate 70. Especially, even though a black matrix is disposed at the first non-display region adjacent to the display region in the LCD device of FIG. 3, an additional black matrix between adjacent pixels is omitted due to a selective reflection property of the CCF layer and a metal bar 78 of one material of a gate pad 74 and a data pad 76 is disposed at the first non-display region "N1" not adjacent to the second non-display region "N2" to prevent light reflection in the reflective LCD device using a CCF layer. However, an extra metal bar to prevent light reflection is not disposed at the first non-display region "N1" adjacent to the second non-display region "N2" where the gate pad 74 and the data pad 76 are formed.
FIG. 5 is a schematic cross-sectional view of a reflective LCD device using a CCF layer according to the related art. A boundary of a display region is mainly shown in FIG. 5.
In FIG. 5, a first substrate 70 including array elements 86 and a second substrate 72 including a CCF layer 82 face each other. Incident light into the CCF layer 82 displays colors by the CCF layer 82 whose pitch is adjusted according to a wavelength of each color. These colors constitute desired images by a refractive index difference at a liquid crystal layer (not shown) interposed between the first and second substrates 70 and 72. To illustrate this in more detail, the array elements 86 are formed on an inner surface of the first substrate 70 and a light absorption layer 80 is formed on an entire inner surface of the second substrate 72. The CCF layer 82 is formed at a display region "D" and a first non-display region "N1" on the light absorption layer 80. A common electrode 84 is formed on the light absorption layer 80 and the CCF layer 82. The array elements 72 on the second substrate 30 of FIG. 3 can be used as the array elements 86.
When external light enters the CCF layer 82 at the first non-display region "N1," the CCF layer 82 reflects a circularly polarized light such as left-handed or right-handed circularly polarized lights and the circularly polarized light is emitted to an exterior without passing through an additional light shielding layer. Accordingly, brightness undesirably increases at a boundary of the display region and a display quality of the reflective LCD device decreases.

Reflective liquid crystal display device having cholesteric liquid crystal color filter and controlled liquid crystal black matrix in the non-display region


A received signal strength indicator according to an aspect of the invention may include a gain calibration section including a calibration limiter, a calibration load unit and a comparison and adjustment unit. The calibration load unit is connected to output terminals of the calibration limiter, and generating an output differential voltage whose gain is a unit gain when a predetermined input differential voltage is input to the calibration limiter, and a comparison and adjustment unit comparing the input differential voltage with the output differential voltage, and adjusting an output of a variable current source included in the calibration limiter so that the input differential voltage becomes identical to the output differential voltage.

1. Field of the Invention
The present invention relates to received signal strength indicators (hereinafter, also referred to as an "RSSI") detecting the power of an RF signal and the like, and more particularly, to received signal strength indicators self-calibrating a gain of a limiter to maintain a constant gain over internal and external variations, such as temperature and process variations.
2. Description of the Related Art
In general, a received signal strength indicator (RSSI) is used to detect the power of an RF signal that is received from a receiver. The RSSI includes a multi-stage amplifier and a plurality of rectifiers. The multi-stage amplifier includes a plurality of limiters connected in series to each other to amplify the received signal in multiple stages. The plurality of rectifiers rectify individual outputs of the limiters included in the multi-stage amplifier, and generate a voltage having a magnitude corresponding to the strength of the received signal. The RSSI may be used for gain calibration of the entire RF system by using a feedback structure.
The RSSI may be manufactured as an RF IC by using a semiconductor process. Because of characteristics of an analog circuit implemented as the RF IC, the characteristics can be changed due to temperature or process variations. For example, variations may occur in the gain of the limiter included in the RSSI, and variations may occur in a direct current output of the rectifier.
Therefore, in the RSSI-related technical field, there has been required a method of calibrating a gain of a limiter and a direct current output of a rectifier according to temperature or process deviations.

Received signal strength indicator self-calibrating gain of limiter


In a terminal, a content reproduction section reproduces a video signal and an audio signal from a received transport stream. A telephony processing section performs processing necessary for voice communication. A status detection section detects a time point at which the status of voice communication changes. A control section writes the transport stream received by the content reproduction section in a content storage section when the status detection section detects start of voice communication, and reads and sends the transport stream stored in the content storage section to the content reproduction section according to a predetermined timing. The content reproduction section reproduces a video signal and an audio signal from the transport stream read by the control section.

1. Field of the Invention
The present invention relates to communications terminal devices, and more particularly, to a communications terminal device having a content reception function and a voice communication function.
2. Description of the Background Art
Terrestrial digital broadcasting is scheduled to commence in Japan first in the three biggest metropolitan areas in 2003 and then nationwide in 2006. A feature of terrestrial digital broadcasting is that mobile reception of contents is possible. As for mobile communications, the third-generation cellular phone service started in 2001, enabling distribution of moving pictures and a portable videophone. Under the present situation as described above, there has been recently announced a concept of a communications terminal device having both the content reception function and the voice communication function. However, when a voice call arrives while viewing a content with such a communications terminal device, the user tends to choose to answer the call rather than continuing viewing the content. In the opposite case, that is, if a content that the user desires to view has started while the user is engaged in voice communication using a mobile communications terminal device, the user tends to continue the voice communication.
There is known in the art a conventional television which receives a video signal externally broadcast on the channel selected by the viewer, reproduces the received video signal, and outputs a video represented by the received video signal. The conventional television includes a built-in modem which outputs a status signal when a fixed telephone receives a call during the reception of the video signal. In response to the status signal, the conventional television begins recording of the currently receiving video signal in a storage device built therein (that is, performs video recording). After the voice communication is finished, the conventional television reproduces the video signal recorded in the storage device. Thus, the viewer can view the video missed due to the voice communication.
The conceptual communications terminal device has a problem that the user is not allowed to view the content at least until the voice communication is finished. As another problem, the conventional television described above needs to have a storage device with a large capacity capable of storing a long content. However, the communications terminal device described above, which is a mobile unit, is allowed to include only a small-capacity storage device and thus cannot store a long content therein. In view of this, it is difficult to implement the technology developed for televisions as described above for a mobile communications terminal device without substantial modifications.

Communications terminal device allowing content reception and voice communication

Matsushita Electric Industrial Co., Ltd.