Patents by Inventor William A Crossland

William A Crossland has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).

  • Patent number: 6812909
    Abstract: Relates to constructions of a backplane which comprises an array of addressable active elements 52 on a semiconductor substrate 51 for selectively energizing respective first electrodes 65 of the array, for example in a liquid crystal matrix cell. To reduce photo-induced degradation of images produced thereby (a) at least part of the region beneath a first electrode is adapted to act as a capacitor, for example a depletion layer 66 acting as a reverse biased diode, and/or (b) substantially the whole of each active element is covered by a metallic conductor (59, 60—coupled to row and column conductors). In a variant of (b) the array of active elements may covered by an insulating layer, and each active element is connected to a metal electrode on the insulating layer, the array of said metal electrodes thus formed covering more than 65% of the area of said array.
    Type: Grant
    Filed: March 1, 2002
    Date of Patent: November 2, 2004
    Assignee: QinetiQ Limited
    Inventor: William A Crossland
  • Patent number: 6762873
    Abstract: Relates to writing an array of optical elements which are each switched between two states according to input data sets. In a first method, data is written in two steps in which different selected elements are respectively driven to one binary state and the other binary state. The selected elements of the two sets may be complementary, but are preferably only those which are required to change from their existing state. The latter criterion may be used in an alternative method using a single addressing of the array to turn elements in either direction as required. In a further method, as shown, selected elements only of a blank array are written in a first WRITE step so as to correspond with a set of data, and in a subsequent second ERASE step the selected elements are selectively erased to restore a blank array prior to writing and erasing another set of data. The methods have particular utility for maintaining a dc balance at pixels of a liquid crystal array.
    Type: Grant
    Filed: January 23, 2002
    Date of Patent: July 13, 2004
    Assignee: QinetiQ Limited
    Inventors: Timothy M Coker, William A Crossland
  • Patent number: 6690444
    Abstract: In active semiconductor backplane (3), for example for a smectic liquid crystal cell, which comprises an array of electronic or elctrical elements in a first region (4), logic elements for addressing said array in a second region spaced from the first, and conductors coupling said first and second regions, the first and second regions are sufficiently widely spaced (21, 22) (providing a “glue lane”) to permit the presence of an adhesive sealing strip therebetween without substantial contact with the first and/or second regions, even when an opposed substrate is sealed thereto. The backplane may comprise spacers (25, 26) in the first region and/or glue lane.
    Type: Grant
    Filed: August 1, 2001
    Date of Patent: February 10, 2004
    Assignee: QinetiQ Limited
    Inventors: Timothy D Wilkinson, William A Crossland
  • Publication number: 20030193491
    Abstract: A display device has a number of pixels to display an image. A first set of electrodes and a second set of electrodes are provided. To display an image in accordance with image data, the first and second sets of electrodes are addressed with a first set of drive signals and a second set of drive signals respectively in order to drive the pixels of the display device. The first set of drive signals is predefined. The image data is compressed. The second set of drive signals is obtained from the compressed image data.
    Type: Application
    Filed: April 14, 2003
    Publication date: October 16, 2003
    Applicant: CAMBRIDGE UNIVERSITY TECHNICAL SERVICES LIMITED
    Inventors: Nicholas A. Lawrence, Timothy D. Wilkinson, William A. Crossland
  • Publication number: 20030174117
    Abstract: An active semiconductor backplane (3) for a matrix liquid crystal display comprises a plurality of mutually exclusive sets of electrically addressable elements defining a pixel array (4), means (44) arranged to address the sets one at a time, and means (44, 45) for addressing more than one of the plurality of sets simultaneously. Preferably the sets are simultaneously addressable rows, for fast blanking. Single pass and two-pass schemes for writing and re-writing the array are described.
    Type: Application
    Filed: March 12, 2002
    Publication date: September 18, 2003
    Inventors: William A. Crossland, Tat C.B. Yu
  • Publication number: 20030161126
    Abstract: In an active semiconductor backplane for a liquid crystal spatial light modulator, spacers (25) which are distributed over the backplane extend above an array of electrical and/or electronic elements and comprise at least two layers essentially of the same material and occuring in the same order as is found in at least one of the electrical or electronic elements, such as an NMOS transistor (52). The latter is formed from a stack of layers on a silicon substrate (51) comprising polysilicon (56), continuous silicon oxide (57) modified to include gate oxide GOX (55), metallic gate electrode (59), continuous silicon oxide (58) and a metallic drain electrode (60) which is coupled to a spaced mirror electrode over the layer (58). Likewise, spacer (25) comprises the layers (57 and 58) with metallic (67, 68) deposited simultaneously with electrodes (59, 60). The foot of layer (57) is differently modified to include field oxide layer (69) and polysilicon layers (70, 72) spaced by thin oxide (71).
    Type: Application
    Filed: February 28, 2002
    Publication date: August 28, 2003
    Inventors: Timothy D. Wilkinson, William A. Crossland, Tat C.B. Yu
  • Patent number: 6285345
    Abstract: A liquid crystal display of the UV-phosphor type comprises a light source 1 for producing activation light at a predetermined narrow range of UV wavelengths, a collimator 3 for directing the activation light in parallel in a predetermined direction, a LC cell 5 formed from an array of pixels, a photoluminescent screen (7) on the cell arranged to emit a visible output when struck by the narrow-band excitation light passing through the cell, and a drive circuit for addressing the LC cell in a multiplexed manner. The direction of the light and the thickness of the cell are chosen to give the best contrast ratio for the liquid crystal. Such an effect is only possible when monochromatic, collimated light is used, which for a normal display is not practical.
    Type: Grant
    Filed: October 29, 1998
    Date of Patent: September 4, 2001
    Assignee: The Secretary of State for Defence in Her Britannic Majesty's Government of The United Kingdom of Great Britain and Northern Ireland
    Inventors: William A Crossland, Anthony B Davey, Vincent G Geake, Ian D Springle
  • Patent number: 6078421
    Abstract: A collimator is formed of a stack of layers (11) of different thicknesses in a way analogous to a low-pass interference filter. When illuminated by narrow-band light of a predetermined wavelength just within the pass band of the filter, the collimator preferentially transmits light incident within a predetermined angular range, usually near-normal. The collimator is especially useful with photoluminescent liquid-crystal display, having phosphor emitters (17), because the collimator layers can simply be deposited on one face of the liquid-crystal modulator (1).
    Type: Grant
    Filed: October 25, 1999
    Date of Patent: June 20, 2000
    Assignee: The Secretary of State for Defence in Her Majesty's Government of the United Kingdom of Great Britain and Northern Ireland
    Inventors: Anthony B. Davey, Paul A. Bayley, Timothy M. Coker, William A. Crossland
  • Patent number: 5576873
    Abstract: Telecommunications switch architectures and switching methods based on the principle of replication/broadcasting some or all of the incoming data from each input-switch port to all output switch ports. The replicated data is transferred to the output ports either by the respective output port reading directly from a relevant address in an input memory, or by transferring the content of all or part of the input memory data simultaneously en bloc and in parallel to a plurality of output memories, with each output port then taking the data intended therefor. The input and output data is in serial form but transferred in parallel form. The data can be replicated optically or electronically. In particular, the input data can be formatted as spatially arranged pages in the optical domain by spatial light modulators (SLM) and switched by an image replicating optical switch, such as a matrix-matrix switch, to an output plane at which a second SLM device converts the data back to serial form.
    Type: Grant
    Filed: May 3, 1995
    Date of Patent: November 19, 1996
    Assignee: Northern Telecom Limited
    Inventors: William A. Crossland, Robert W. Scarr, Martin J. Birch, Adrian P. Sparks
  • Patent number: 5408248
    Abstract: In an active back-plane co-ordinate addressed liquid crystal cell exhibiting an analogue optical response to the application of an analogue electric potential, refreshing is carried out in two sequential stages in order to avoid cumulative charge imbalance effects. In one stage the pixels are set to their required optical states using the appropriate applied potential differences, and in the other stage the pixels are set with the same potential differences, but applied the other way round.
    Type: Grant
    Filed: February 24, 1993
    Date of Patent: April 18, 1995
    Assignee: Northern Telecom Limited
    Inventors: William A. Crossland, Martin J. Birch
  • Patent number: 5339090
    Abstract: A smart pixel is comprised by a chiral smectic liquid crystal light modulator (45) (ferro-electric or electroclinic) disposed on a semiconductor substrate and having associated therewith electronic circuitry (41-44) formed in the semiconductor substrate in particular a single crystal silicon VLSI substrate, which circuitry is such as to provide localised intelligence (electrical signal processing and conditioning, pointwise operations, logic functions) at the modulator. The circuitry may comprise photodetector/threshold circuitry (FIG. 7) or digital-to-analogue conversion (FIGS. 3 or 4), for example.
    Type: Grant
    Filed: September 10, 1992
    Date of Patent: August 16, 1994
    Assignee: Northern Telecom Limited
    Inventors: William A. Crossland, David Vass, Neil Collings
  • Patent number: 4992654
    Abstract: An optical logic device consists of a bistable liquid crystal layer (BOD 1) of the thermally-induced birefringent (TIB) type settable by one or more write beams and rfead by a beam of a different wavelength or different light polarization. Thus the read and write beams are optically decoupled. Two such devices (BOD 1 and BOD 2) in tandem form a 3-input AND gate. Here beams A and B are write beams for the first device, (BOD 1), and beam C is the read beam for the first device. For the second device (BOD 2) the write beams are the output of the first device (BOD 1) and beam D, the read beam being beam E. The two read beams have different wavelengths from the write beam. In a second version, the liquid crystal layer is on the base of a prism via which the beams reads it. Write beams go right through the layer, while a read beam is "reflected" from the layer but is modulated by the state thereof. This is an OR gate. Logic assemblies can use combinations of such AND or OR gates.
    Type: Grant
    Filed: August 1, 1988
    Date of Patent: February 12, 1991
    Assignee: STC PLC
    Inventors: William A. Crossland, Neil Collings
  • Patent number: 4799775
    Abstract: Bistable operation of ferroelectric liquid crystal smectic I* or smectic F* display cells is disclosed which uses a greater liquid crystal layer thickness than is achievable with smectic C* material while yet retaining bistability of operation.
    Type: Grant
    Filed: March 31, 1987
    Date of Patent: January 24, 1989
    Assignee: STC PLC
    Inventors: William A. Crossland, Anthony B. Davey, Matthew F. Bone
  • Patent number: 4793670
    Abstract: Optical four wave mixing is provided by interfering two waves on a liquid crystal layer (1) temperature stabilized just beneath its nematic/isotropic phase change transition temperature. The liquid crystal incorporates a guest dye to absorb the light producing a holographic thermal image which is accompanied by a holographic phase image. Once this phase image starts to build up it is illuminated with a `third wave` of light that is not absorbed so as to produce the required holographically diffracted `fourth wave`.
    Type: Grant
    Filed: July 7, 1986
    Date of Patent: December 27, 1988
    Assignee: STC PLC
    Inventors: William A. Crossland, Peter W. Ross, Neil Collings
  • Patent number: 4722594
    Abstract: Bistable operation of ferroelectric liquid crystal smectic I* or smectic F* cells is disclosed which uses a greater liquid crystal layer thickness than is achievable with smectic C* material while yet retaining bistability of operation. One or more such cells are employed in two-dimensional information processing apparatus.
    Type: Grant
    Filed: November 14, 1985
    Date of Patent: February 2, 1988
    Assignee: STC plc
    Inventors: William A. Crossland, Anthony B. Davey, Neil Collings, Matthew F. Bone
  • Patent number: 4720781
    Abstract: The data processing terminal comprises a smectic liquid crystal flat panel display module (2) which is supported by a support module (1). The terminal also includes a keyboard (4). The display module (2) may be removed from the support module (1) and has its own central processor, memory, control means and power source to enable it to operate independently of the support module, which contains its own central processor, memory, control means, and interface means and is mains operated. The display module may incorporate a touch sensitive overlay to permit the manipulation of the contents of the display. The support unit may incorporate a telephone interface unit.
    Type: Grant
    Filed: November 16, 1984
    Date of Patent: January 19, 1988
    Assignee: STC PLC
    Inventors: William A. Crossland, Jack R. Peters, Harry J. Smith, Frank Astorino
  • Patent number: 4701029
    Abstract: A laser beam addressed smectic display in which the laser beam is used to write clear tracks in an optically scattering field employs an anisotropic conductivity dopant in the liquid crystal filling so that the cell can be electrically set into the scattering state by means of dynamic scattering effects. This requires the use of a laser light absorbing dye that is not only photochemically stable, but also stable against the effects of the relatively high fields and currents present when the cell is being set into the scattering state.
    Type: Grant
    Filed: July 10, 1985
    Date of Patent: October 20, 1987
    Assignee: Standard Telephones and Cables Public Limited Company
    Inventors: William A. Crossland, Christopher J. J. Walker, Anthony B. Davey
  • Patent number: 4655550
    Abstract: A ferro-electric liquid crystal display in which the individual pixels are addressed via an address matrix that includes one field effect transistor for each pixel, and a plurality of row and column conductors whereby data is written into each pixel to change or to maintain its display condition.
    Type: Grant
    Filed: October 22, 1984
    Date of Patent: April 7, 1987
    Assignee: International Standard Electric Corporation
    Inventors: William A. Crossland, Peter J. Ayliffe
  • Patent number: 4653857
    Abstract: Optical four wave mixing is provided by interfering two waves on a liquid crystal layer (1) temperature stabilized just beneath its nematic/isotropic phase change transition temperature. The liquid crystal incorporates a guest dye to absorb the light producing a holographic thermal image which is accompanied by a holographic phase image. Illumination of this phase image with a `third wave` of different wavelength is then used to produce the required holographically diffracted `fourth wave`.
    Type: Grant
    Filed: August 14, 1986
    Date of Patent: March 31, 1987
    Assignee: Standard Telephones and Cables, PLC
    Inventors: William A. Crossland, Peter W. Ross, Neil Collings
  • Patent number: 4626074
    Abstract: A relatively shallow arrangement for providing illumination for a light scattering type display cell employs a transparent sheet in optical contact with the front surface of the cell and a matte black sheet out of contact with the rear surface. The assembly acts as a light guide for light launched into at least one of the transparent sheet from at least one strip lamp. The only light escaping from the display, etc. in the direction of the observer is a proportion of that scattered into non-guided directions by regions of liquid crystal layer selectively set into a scattering state.
    Type: Grant
    Filed: April 30, 1984
    Date of Patent: December 2, 1986
    Assignee: International Standard Electric Corporation
    Inventors: William A. Crossland, John R. Brocklehurst, Peter J. Ayliffe, Arthur Atkinson