HKUST Institutional Repository
(5.016 recursos)
Repository of Hong Kong University of Science and Technology. Managed by the HKUST Library.
Mostrando recursos 1 - 20 de 79
1.
Method of manufacturing photo-alignment layer - Yip, Wing C.; Prudnikova, Elena K.; Kwok, Hoi-Sing; Chigrinov, Vladimir Grigorievic; Kozenkov, Vladimir M.; Takada, Hirokazu; Fukuda, Masanobu
A photo-alignment layer having excellent long-term stability to light and heat is manufactured by coating a material for the photo-alignment layer, which contains a dichroic dye having two or more polymerizable groups per molecule, on a substrate, and exposing the coating layer to polarized light, thereby imparting a photo-alignment function, and polymerizing the polymerizable groups by heating or light exposure.
2.
Toy system - Lau, Jack; Lo, Chi Wa; Keung, Chun Yeung
A toy is disclosed as including a baton-like transmitter and a doll which includes an infrared signal receiver for receiving infrared signals from the signal transmitter, in which the doll produces sound, e.g. songs, in response to signals received from the signal transmitter, and the signals are transmitted by the signal transmitter upon movement of the signal transmitter.
3.
Electro-optic display providing a grey scale by utilizing voltage dependent birefringence - Liao, York; Kwok, Hoi-Sing
The invention relates to an active matrix liquid crystal display device based on voltage control (non-zero driving voltage) of the birefringence (negative or positive) of the liquid crystal cell. In the device a ground (earth) plate comprises a piece of glass with a transparent conductive coating, such as indium tin oxide. A silicon wafer with integrated circuits on it has a coating of polymer for aligning liquid crystal molecules. The coated glass also has a coating for aligning the liquid crystal molecules.
4.
Reflective active matrix liquid crystal displays with mixed twisted nematic and birefringent modes - Kwok, Hoi-Sing
A generalized mixed twisted nematic/birefringent effect mode is presented for reflective liquid crystal displays with only one polarizer. This new MTB mode encompasses all previously published reflective nematic liquid crystal display modes and is clearly shown on the parameter space diagrams. The invention of how to obtain operating conditions of this generalized mixed mode display is discussed. For any given angle between the polarizer and the input director of the liquid crystal cell, a unique range of values of the twist angle and the retardation d?n for efficient reflection and low dispersion is defined.
5.
Polarizing beam splitter - Kwok, Hoi-Sing; Li, Hai-Feng
A polarizing beam splitter is described that is optimised not for the maximum possible extinction ratio, but to provide a wide acceptance angle over substantially the whole visible range while still providing an adequate extinction ratio for use in specific applications such as a LCD projector display.
6.
Optical systems for liquid crystal display projecters - Kwok, Hoi-Sing; Huang, Ho-Chi
The present invention describes several embodiments of optical systems for the projection of images formed on reflective liquid crystal light valves. These light valves are capable of high resolution and very small sizes. The optical systems described are able to project these images with highly efficient utilization of light from an arc lamp source and are also very compact and easy to manufacture.
7.
Optical assembly for reflective light valves - Kwok, Hoi-Sing; Liu, Xu
An optical system for reflective mode light valve full color display, and more particularly a compact and highly optically efficient trichroic prism assembly (TPA), and a polarizing beam splitter (PBS). The TPA and PBS combination is placed between the objective lens and the LCD panel or other kind of reflective light valves to form a compact projection system.
8.
Projector with flat light sources - Kwok, Hoi-Sing
Optical system designs for projectors using flat light sources are disclosed. These projectors make use of imagers that manipulate the transmission or reflectance of light through electronically controlled pixels. The optical systems of the invention employ a rectangular flat light source that is matched to the aspect ratio of the imager itself, thus enabling very efficient use of light. Several flat light sources are possible for this projection system, including flat fluorescent lights and field emission light sources. Collimation of these light sources is an option. Polarization conversion means is also disclosed for such flat light sources, so that the...
10.
A liquid crystal alignment layer and methods of making thereof - Kwok, Hoi-Sing; Yeung, Fion Sze Yan; Xie, Fengchao; Tsui, Ophelia K. C.; Sheng, Ping
The present invention relates to a liquid crystal alignment layer used in a liquid crystal cell, which is capable of providing high pretilt angles.
11.
Liquid crystal display with nonspecular reflectors - Yeoh, Colin T.; Kwok, Hoi-Sing; Liao, York
The present invention deals with liquid crystal displays where the incident light and reflected light going through the display are not specularly related. The incident light can be at a range of angles to the display while the reflected light, i.e. the viewing direction is at or nearly normal to the display. For such nonspecular liquid crystal displays, the polarizer angles, the input/output directors of the liquid crystal cell, and liquid crystal cell retardation have to be specially optimized to obtain the best viewing effects. Conventional liquid crystal display modes do not work optimally in this nonspecular situation. We also...
12.
Information network architecture - Lea, Chin-Tau
An information network architecture is described that can handle both ATM and IP traffic. The network emplpoys unbuffered switches that employ a system of priorities in the handling of ATM and IP traffic whereby ATM data is given higher priority to IP traffic, and the remaining cells of an IP packet that is being transmitted are given greater priority than the first cells of a new IP packet so that the cells of different IP packets are not interleaved.
13.
Single polarized LCD consisting of particular twist angle and thickness-birefringence product - Kwok, Hoi-Sing; Tang, S. T.
A liquid crystal display is described in which the need for a conventional output polarizer is eliminated and the display comprises only a liquid crystal cell, a single input polarizer, a reflector placed behind the cell, and a retardation film placed between the reflector and the cell. A Jones matrix simulation approach is used in order to obtain the parameters corresponding to solution spaces for the above design and several combinations are disclosed that give good results.
14.
Method and apparatus for measuring liquid crystal cell properties - Kwok, Hoi-Sing; Tang, S. T.
The present invention relates to methods and apparatus for measuring the optical properties, eg twist angle, cell gap, input director, of a transmissive or reflective liquid crystal cell. For a transmissive liquid crystal cell the cell is placed between a polarizer and an analyzer and the transmission spectrum observed while rotating the analyzer until zero transmission is obtained at at least on wavelength. The twist angle and the surface rubbing orientations of the liquid crystal cell are determined by the relative angle between the polarizer and the analyzer while the cell gap is determined from the calculated retardation value d?n...
15.
Packet scheduling system - Tsang, Danny H. K.; Bensaou, Brahim; Chan, King Tung
A packet scheduling system is disclosed in which a plurality of first-in-first-out input buffers are provided each corresponding to a respective input data stream to a switching node or multiplexer. Credit is allocated to each stream having pakets waiting to be transmitted and which is unable to transmit, and the next stream to be transmitted is based on the allocated credit values, the credit of a transmitted stream being reduced after transmission of a data packet from that stream.
16.
Switched-opamp technique for low-voltage switched capacitor circuits - Cheung, Sin Luen; Luong, Howard Cam
A switched capacitor circuit is described that uses two switchable operational amplifiers that operate in parallel and in alternate clock phases. In a preferred embodiment of the invention, the two operational amplifiers may be implemented by a single two-stage operational amplifier having a common input stage and two switchable output pairs. The novel switched capacitor circuit may be used in any application that uses a conventional switched capacitor circuit, such as an integrator and a filter means.
17.
Method and apparatus for fluorescence imaging of tissue - Qu, Jianan
Fluorescence imaging of tissue is used as a diagnostic tool in which geometric effects and specular reflections are compensated for by normalizing a fluorescence image with a cross-polarized image.
18.
Steerable and scalable spatial filters - Shi, Bertram
A circuit architecture for computing the outputs of odd and even symmetric spatial filters simultaneously comprises at least two resistive networks interconnected by at least one controlled current source. In one embodiment the nodes of the resistive network are arranged in a two-dimensional array to allow filtering of two-dimensional signals such as images. The resulting filters are orientation selective. The spatial orientation and the scale of the filter can be selected by appropriately tuning the resistive elements forming the resistive networks and the gains of the controlled sources. The controlled sources may be voltage controlled (eg transconductance amplifiers) or current...
19.
Low-complexity antenna diversity receiver - Ling, Curtis C.; Chuang, Justin C.; Zhang, Chunning
A low-diversity antenna diversity receiver suitable for TDMA PCS handset implementation employing two diversity branches. The receiver is capable of selecting a diversity scheme which is anticipated to give optimum signal reception among a plurality of diversity schemes installed on the receiver. This receiver, more conveniently termed multi-diversity receiver comprises a single conventional wireless digital receiver chain augmented with a few additional low-cost passive RF components and minor control circuits. A plurality of diversity algorithms, for example, selection diversity (SD), equal-gain combining (EGC) or interference-reduction combining (IRC) scheme, which are suitable for implementing on this multi-diversity receiver are also described....
20.
Phase-controlled dimmable ballast - Ki, Wing-Hung; Mok, Philip; Sin, Johnny K. O.
A method and apparatus are disclosed for the dimming control of a fluorescent lamp driven by an electronic ballast. A small portion (eg less than 15°) of the phase of the input supply voltage is removed, and the precise amount of the phase removed is used to generate a switching signal that controls the switching frequency of the electronic ballast and hence the light power output. The switching frequency is generated by producing pulses of a width proportional to the amount of phase removed, integrating the pulses to produce a voltage proportional to the phase removed, converting that voltage to...
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