With Photoconductive Layer (e.g., Spatial Light Modulator(slms)) Patents (Class 349/25)
  • Patent number: 6104448
    Abstract: A new liquid crystalline light modulating cell and material are characterized by liquid crystalline light modulating material of liquid crystal and polymer, the liquid crystal being a chiral nematic liquid crystal having positive dielectric anisotropy and including chiral material in an amount effective to form focal conic and twisted planar textures, the polymer being distributed in phase separated domains in the liquid crystal cell in an amount that permits the liquid crystal to change textures upon the application of a field and ruggedizes the structure. In still another embodiment, the material exhibits stability at zero field in a colored, light reflecting state, a light scattering state and multiple stable reflecting state therebetween, as well as being optically clear in the presence of a field. In yet another embodiment, the application of mechanical force to the cell changes the material from an optically clear state to a light reflecting state.
    Type: Grant
    Filed: December 15, 1999
    Date of Patent: August 15, 2000
    Assignee: Kent State University
    Inventors: J. William Doane, Deng-Ke Yang, Liang-Chy Chien
  • Patent number: 6100945
    Abstract: A display system for acting on light entering the system includes a reflective ferroelectric liquid crystal spatial light modulator and a polarizer arrangement. The polarizer arrangement includes a polarizer for polarizing the light entering the system and directing the polarized light into the spatial light modulator along an optical path having an optical path axis. The reflective spatial light modulator acts on the polarized light to produce an optical output that is directed from the spatial light modulator back into the polarizing arrangement along substantially the same optical path axis that the polarized light is directed into the spatial light modulator. The polarizing arrangement also includes an analyzer configured to receive and analyze the optical output of the spatial light modulator and to direct the analyzed optical output out of the system.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: August 8, 2000
    Assignee: Displaytech, Inc.
    Inventors: Charles M. Crandall, Mark A. Handschy, Michael R. Meadows, Bradley J. Sissom
  • Patent number: 6094249
    Abstract: A spatial light modulator includes at least three picture elements, each of which includes a plurality of first elongate electrodes which are connected together and a plurality of second elongate electrodes which are connected together and which are interdigitated with the first electrodes. The first electrodes of a second of the picture elements are connected to the second electrodes of a first of the picture elements and the second electrodes of the second picture element are connected to the first electrodes of a third of the picture elements.
    Type: Grant
    Filed: July 29, 1998
    Date of Patent: July 25, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Michael Geraint Robinson, Craig Tombling, Nicholas Mayhew, Paul Bonnett, Michael John Towler
  • Patent number: 6091463
    Abstract: A diffractive spatial light modulator includes: a layer of electro-optic material; a first electrode arrangement substantially covering a first side of the layer; and a second electrode arrangement substantially covering a second side of the layer. The first electrode arrangement includes a plurality of sets of elongate electrodes, and the elongate electrodes of each of the sets are electrically connected together and interdigitated with the elongate electrodes of at least one of the other acts. The second electrode arrangement includes a plurality of discrete picture element electrodes.
    Type: Grant
    Filed: January 28, 1998
    Date of Patent: July 18, 2000
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Michael Geraint Robinson, Craig Tombling, Nicholas Mayhew, Mitsuhiro Koden, Michael John Towler
  • Patent number: 6079833
    Abstract: An image projection system is provided for generating an energy efficient output representative of a desired input image. The image projection system includes a light source positioning device for directing the light from a light source onto a spatial light modulator. An image source provides the desired image to the spatial light modulator and also image information to a light source position controller for coordinating the light source positioning device, such that the light from the light source impinges substantially only the area of the spatial light modulator which contains the desired image. In particular, the controller actuates the light source positioning device by using a predefined scan that corresponds to the desired image. The spatial light modulator modulates the light with the desired input image and generates an output representative of the desired image.
    Type: Grant
    Filed: February 17, 1999
    Date of Patent: June 27, 2000
    Assignee: Hughes-JVC Technology Corporation
    Inventors: Barney J. Kaelin, Stephen J. Reinsch
  • Patent number: 6075577
    Abstract: A reflection mode, ferroelectric liquid crystal spatial light modulating system, includes a light reflecting type spatial light modulator. The spatial light modulator has a light reflecting surface cooperating with a layer of ferroelectric liquid crystal light modulating medium switchable between first and second states so as to act on light in different first and second ways, respectively. A switching arrangement switches the liquid crystal light modulating medium between the first and second states and an illumination arrangement produces a source of light. An optics arrangement is optically coupled the spatial light modulator and the illumination arrangement such that light is directed from the source of light into the spatial light modulator for reflection back out of the modulator and such that reflected light is directed from the spatial light modulator into a predetermined viewing area.
    Type: Grant
    Filed: September 4, 1999
    Date of Patent: June 13, 2000
    Assignee: Displaytech, Inc.
    Inventor: Charles M. Crandall
  • Patent number: 6037922
    Abstract: An optical modulation unit is constituted by a light source periodically turned on, and an optical modulation means including an optical modulation element and periodically turned on. The optical modulation unit is driven by changing a voltage applied to the optical modulation element depending on given graduation data so as to modulate an overlapping time between an ON period of the optical modulation means and a lighting period of the light source. The gradation data may be analog gradation data and may be carried by light illuminating the optical modulation element synchronized with a voltage applied to the optical modulation element.
    Type: Grant
    Filed: June 12, 1996
    Date of Patent: March 14, 2000
    Assignee: Canon Kabushiki Kaisha
    Inventor: Mineto Yagyu
  • Patent number: 6031588
    Abstract: A device featuring liquid crystals for local reduction of the intensity of incident light is described. This device protects the eyes or the video camera against blinding, or the light-sensitive medium against local damage by automatically reducing the intensity of the incident light emitted by brightly illuminated objects, while the brightness of poorly illuminated objects is not suppressed. The device uses optically addressed spatial light modulators (OASLM) on the basis of a semitransparent photoconducting film in contact with ferroelectric liquid crystals (FLC). The DHF effect (deformation of the helix structure) in ferroelectric liquid crystals (FLC) with helix-shaped structure is used here. The drive voltage has a frequency of 10.sup.2 to 10.sup.3 Hz at an amplitude of .+-.20 V, which is 10-50 times higher than that of devices operating with nematic liquid crystals. The device allows moving objects to be observed against the background of a bright light source (sun, lamp, etc.).
    Type: Grant
    Filed: April 23, 1997
    Date of Patent: February 29, 2000
    Assignee: Deutsche Telekom AG
    Inventors: Wolfgang Dultz, Arkadii Onokhov, Leonid Beresnev, Wolfgang Haase
  • Patent number: 6028694
    Abstract: An illumination device utilizing a pulse modulation technique of a solid state light source to provide increased light output for a given heat load. In a preferred embodiment, power is supplied in pulses to periodically activate a short wavelength (i.e., blue) emitting LED, which in turn stimulates a phosphor-based color conversion system to produce sustained white light. In response to a pulse of power, the LED emits an intense burst of short wavelength light. The burst of light from the LED briefly excites the phosphor system, producing a bright illumination. During the interval while power is dissipated in the LED, the LED warms. After the pulse ends and before the next pulse begins, the LED cools because no more power is dissipated in the LED. However, the phosphorescent behavior of the phosphor system causes it to continue to glow for a period of time after being excited. The intensity of the illumination produced by the phosphor gradually decays during this period.
    Type: Grant
    Filed: May 22, 1998
    Date of Patent: February 22, 2000
    Inventor: Gregory W. Schmidt
  • Patent number: 6025890
    Abstract: A display system includes a reflective mode spatial light modulator for producing a pattern of polarized light, a light source for illuminating the spatial light modulator, and an optics arrangement. The optics arrangement includes a beam splitter element having a transparent substrate with a front face and a back face. The front face supports a beam splitter coating acting as a beam splitter. The back face supports a polarizer layer. The polarizer layer and the transparent substrate are configured to be refractive index matched to prevent the reflection of light at the interface between the transparent substrate and the polarizer layer. The beam splitter element is positioned in the optical path between the light source and the spatial light modulator in order to polarize and direct light from the light source to the spatial light modulator.
    Type: Grant
    Filed: February 20, 1998
    Date of Patent: February 15, 2000
    Assignee: Displaytech, Inc.
    Inventor: Holden Chase
  • Patent number: 6016173
    Abstract: A reflection mode, ferroelectric liquid crystal spatial light modulating system, includes a light reflecting type spatial light modulator. The spatial light modulator has a light reflecting surface cooperating with a layer of ferroelectric liquid crystal light modulating medium switchable between first and second states so as to act on light in different first and second ways, respectively. A switching arrangement switches the liquid crystal light modulating medium between the first and second states and an illumination arrangement produces a source of light.
    Type: Grant
    Filed: February 18, 1998
    Date of Patent: January 18, 2000
    Assignee: Displaytech, Inc.
    Inventor: Charles M. Crandall
  • Patent number: 6008785
    Abstract: A method of automatically generating a load/reset sequence for a display system having a spatial light modulator whose display elements that are loaded with data and reset between loads (FIG. 7). Bit-planes of data are classified according to their display times as normal, short, or reset-release (FIG. 5). Extra time of normal bit-planes is calculated (FIG. 5). The display times of normal bit-planes are adjusted by subtracting or adding extra time, such that any normal bit-plane displayed before a short or reset-release bit-plane includes sufficient extra time to allow for loading the short or reset-release bit-plane (FIG. 7). Also, reset conflicts are detected and avoided (FIGS. 7, 8, 9A and 9B).
    Type: Grant
    Filed: November 20, 1997
    Date of Patent: December 28, 1999
    Assignee: Texas Instruments Incorporated
    Inventors: Gregory J. Hewlett, Donald B. Doherty
  • Patent number: 5990853
    Abstract: The present invention relates to a projection type image displaying apparatus capable of displaying larger picture images which are bright, uniform and after-image-free.
    Type: Grant
    Filed: November 17, 1997
    Date of Patent: November 23, 1999
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasunori Kuratomi, Akio Takimoto, Koji Akiyama, Hiroshi Tsutsui, Toshikatsu Kawakami, Yasuaki Muto, Hiroshi Miyai
  • Patent number: 5933201
    Abstract: The present invention relates to a polymer dispersion liquid crystal recording medium containing liquid crystals dispersed and fixed in resin, as well as to a method and an apparatus for reproducing information. In particular, when a medium as shown in FIG. 6 is used, the information recorded on the liquid crystal layer can be read with sufficient contrast by making the photoconductive layer (13) transparent to blue or ultraviolet light, and by making the wavelength of the reading light match the wavelength of the blue or ultraviolet light. When image reading is performed as illustrated in FIGS. 3 and 7, a white light source is used as light source (4), and a filter (5) is placed between light source (4) and the liquid crystal medium (20); thus, only blue or ultraviolet light enters the liquid crystal medium. After passing through the liquid crystal medium (20), the light is converted to an electric signal by a photoelectric converter (6).
    Type: Grant
    Filed: November 18, 1996
    Date of Patent: August 3, 1999
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventor: Masato Okabe
  • Patent number: 5914764
    Abstract: A system and technique for controlling LCDs based upon measurement of optical response is disclosed, which includes a light source and a light detector on opposite sides of an independently driven test area of a LCD panel. A determination of the optical response time is made by comparing the varying signals from the LCD drive and the response detector and then changing the operation of the LCD panel or heater based upon the comparison.
    Type: Grant
    Filed: September 25, 1996
    Date of Patent: June 22, 1999
    Assignee: Rockwell International Corporation
    Inventor: James P. Henderson
  • Patent number: 5905547
    Abstract: The present invention provides an information recording medium having a liquid crystal phase, which can be repeatedly used. In an information recording medium where an information recording layer comprising a liquid crystal phase and a resin phase is laminated on an electrode, a mixture containing a smectic liquid crystal having good memory property and a liquid crystal having low memory property is used as the liquid crystal phase, the information recorded on the liquid crystal disappears as time elapses without being heated and the information recording medium can be repeatedly used for further information recording.
    Type: Grant
    Filed: August 1, 1996
    Date of Patent: May 18, 1999
    Assignee: DAI Nippon Printing Co., Ltd.
    Inventors: Osamu Shimizu, Hironori Kamiyama, Shyouji Takeshige
  • Patent number: 5856814
    Abstract: A display apparatus includes an optical modulation device comprising a pair of electrodes, and a photoconductor layer and an optical modulation substance layer between the electrodes, a signal light source for supplying light data carrying gradation data to the photoconductor layer, and a readout light source for supplying readout light for reading out image data to the optical modulation substance layer. The display apparatus is driven by a method including: scanningly supplying the light data to the photoconductor layer, and scanningly supplying the readout light to the optical modulation substance layer. Preferably, the lighting time of the readout light source is controlled to modulate an overlapping time between a period of the optical modulation substance assuming a prescribed optical state and the lighting time depending on given gradation data.
    Type: Grant
    Filed: August 1, 1996
    Date of Patent: January 5, 1999
    Inventor: Mineto Yagyu
  • Patent number: 5851710
    Abstract: As shown in FIG. 1a, the information recording medium of the present invention includes an information recording layer on an electrode layer (13), said recording layer made up of a resin system (11) having liquid crystal phases (12) dispersed and fixed therein. In said recording layer, the refractive index of light through said resin system is such chosen as to be substantially coincident with the refractive index of light through the liquid crystal material which is being oriented by an electric field, whereby electrostatic information can be recorded and stored on the recording medium as visible information and the recorded and stored information can be reproduced at any desired time. The present recording medium can also be recycled, if the information recorded on it is erased.
    Type: Grant
    Filed: January 3, 1997
    Date of Patent: December 22, 1998
    Assignee: Dai Nippon Printing Co., Ltd.
    Inventors: Masayuki Iijima, Masato Okabe
  • Patent number: 5847778
    Abstract: In a projection type video display device comprising a light writing type spacial light modulator, disturbances brought about by a resetting pulse and appearing in a projected picture as a black belt or beat are prevented. This is accomplished by causing the resetting pulse, which is to withdraw electric charges produced by incoming writing light and accumulated in spacial light modulator, to occur within a vertical blanking period synchronized with vertical synchronization signal.Further, by changing the pulse width and the voltage of the resetting pulse in accordance with vertical synchronization frequency, pictures of a certain fixed brightness are made available against various vertical synchronization frequencies; and even with a high vertical synchronization frequency, projected pictures are never annoyed by such disturbance that is caused by a resetting pulse dislocated out of the vertical blanking period.
    Type: Grant
    Filed: July 3, 1996
    Date of Patent: December 8, 1998
    Assignee: Matsushita Electric Industrial Co., Ltd.
    Inventors: Yasuaki Muto, Hiroshi Miyai, Akio Takimoto, Yasunori Kuratomi, Toshikazu Kawakami, Hiroshi Noguchi
  • Patent number: 5841489
    Abstract: In a spatial light modulator of the present invention, a photoconductive layer formed of photoconductive material receives write light having a spatial distribution in its intensity and changes resistivity of the photoconductive material dependently on the spatial distribution in the intensity of the received write light. A liquid crystal layer formed of liquid crystal molecules of nematic phase receives read light and presents birefringence with respect to the received read light. An electric voltage is applied through the photoconductive layer and the liquid crystal layer to thereby produce an electric field in the liquid crystal layer. The photoconductive layer changes the electric field produced in the liquid crystal layer in accordance with the resistivity of the photoconductive material so as to electrically control the birefringence of the liquid crystal molecules.
    Type: Grant
    Filed: July 30, 1993
    Date of Patent: November 24, 1998
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Narihiro Yoshida, Naohisa Mukohzaka, Haruyoshi Toyoda, Terushige Hori, Yuji Kobayashi, Tsutomu Hara
  • Patent number: 5815598
    Abstract: In an individual identification apparatus, a hologram 11 recorded on a card is irradiated with laser light to read out a fingerprint image of a specific person. A finger of an arbitrary person to be identified with the specific person is irradiated with laser light to obtain a fingerprint image. Thus obtained fingerprint images are jointly written in a first SLM. Then, the joint image is read out and Fourier transformed to obtain a Joint Fourier Transform image, which is then written in a second SLM. The Joint Fourier Transform image is then read out and Fourier transformed to obtain a pair of output correlation peaks. A photodetector detects the intensity of the output correlation peaks and outputs a signal indicative of the intensity. A threshold processor compares the value of the signal with a predetermined threshold value to positively or negatively identify the arbitrary person with the specific person.
    Type: Grant
    Filed: November 19, 1997
    Date of Patent: September 29, 1998
    Assignee: Hamamatsu Photonics K.K.
    Inventors: Tsutomu Hara, Yuji Kobayashi, Haruyoshi Toyoda
  • Patent number: 5805243
    Abstract: A liquid crystal display apparatus which includes: a light-addressed liquid crystal light valve including a photoconductive layer and a liquid crystal layer between a pair of light transmitting substrates, each of the light transmitting substrates having an electrode for applying a voltage across the photoconductive layer and the liquid crystal layer; a writing unit for writing an image of a display medium in the light-addressed liquid crystal light valve with writing light from the display medium through a writing lens; a projecting unit for projecting the image written in the light-addressed liquid crystal light valve by irradiating reading light from a projection light source to the light-addressed liquid crystal light valve; and a controlling unit for controlling at least one of operational characteristics of the light-addressed liquid crystal light valve and a luminance of the writing light in accordance with a luminance of the display medium, is disclosed.
    Type: Grant
    Filed: April 5, 1996
    Date of Patent: September 8, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Akitsugu Hatano, Hiroshi Hamada
  • Patent number: 5797050
    Abstract: A real-time, optical, nonlinear attenuator device situated in the image plane of an ocular of special construction provides a highly sensitive, broad spectral band, selective, glare reduction ocular. This system is suitable for the eye or camera which is directed at scenery with illumination ranging from that of a room interior to outside daylight. Special adaptations from spatial light modulator technology and modifications of optical power limiter art increase the nonlinear attenuator device sensitivity to bright light by orders of magnitude over that in current systems using known passive, optical, nonlinear materials. The ocular concept includes an input lens which gathers more light rays than can pass to the eye in order to further enhance nonlinear sensitivity, contains places for filters, operates with either an absorption-promoting or scattering nonlinear device in the intermediate image plane, corrects image inversion and provides embodiments for transmissive or reflective operation.
    Type: Grant
    Filed: February 18, 1997
    Date of Patent: August 18, 1998
    Inventor: James Lynn Smith
  • Patent number: 5729305
    Abstract: A lens is arranged to form a spatially varying intensity distribution at a photoreceptor within a pixel region so as to form a charge pattern thereon. The photoreceptor is associated with a liquid crystal device such that the presence of a suitable recording voltage across the photoreceptor and liquid crystal device causes regions of the liquid crystal device to switch to an opaque state when the light intensity on an associated region of the photoreceptor exceeds a threshold value l.sub.th. Removal of the recording voltage allows the image held in the liquid crystal device to be stored in a non-volatile manner and to be replayed by illumination with a read beam. An analog image having a grey scale can be reproduced from the pixel region. A plurality of pixel regions can be provided as an array so as to record and replay monochrome images.
    Type: Grant
    Filed: June 20, 1995
    Date of Patent: March 17, 1998
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Michael Geraint Robinson, Craig Tombling
  • Patent number: 5712066
    Abstract: Provided an image forming method comprising the steps of;forming electric charges on a recording layer by charging the recording medium comprising a conductive substrate and, provided thereon a photoconductive layer and a recording layer containing a polymeric liquid crystal compound, in this order;irradiating, after the step of charging, said recording medium with a light corresponding to an image information to move electric charges to said photoconductive layer; andwriting said image information by means of changing a birefringence of the recording layer caused by said movement of electric charges.
    Type: Grant
    Filed: May 22, 1995
    Date of Patent: January 27, 1998
    Assignee: Canon Kabushiki Kaisha
    Inventors: Kazuo Yoshinaga, Shuzo Kaneko, Kazuo Isaka, Yoshio Takasu
  • Patent number: 5693958
    Abstract: A light-writing-type liquid crystal element which is provided with carrier-blocking layers that are installed on the transparent electrode side and on the light-shielding layer side of a photoconductive layer and that prevents carriers from entering the photoconductive layer. By adjusting the width of a depletion layer that is formed by the carrier-blocking layers and other factors, the energy-band structure of the photoconductive layer is kept asymmetric so that when a voltage is applied onto the photoconductive layer, the area on the writing-light incident-side of the photoconductive layer receives a higher voltage than that of the area on the liquid-crystal-layer side. Consequently, the photosensitivity of the photoconductive layer is improved, and the resolution as well as the contrast of the element can be improved.
    Type: Grant
    Filed: January 18, 1996
    Date of Patent: December 2, 1997
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Hiroshi Torihara, Akitsugu Hatano, Shinpei Higashida
  • Patent number: 5663832
    Abstract: The present invention discloses a device for and method of simulating an image in real time under turbulent atmospheric conditions. The present invention is realized by expanding a first laser beam using a microscope-objective and a first lens. The expanded light is then projected onto a first LCLV. Light reflecting from the first LCLV is filtered, focused onto a diaphram, polarized, and directed along a path that is around two meters in length. The light is then split into a first beam and a second beam. The first beam is focused onto an optical fiber bundle which is connected to the first LCLV. One end of the optical fiber bundle is rotated with respect to the other end. The second beam is projected upon a second LCLV. A second laser beam is expanded and projected onto a LCTV. The image is provided to the LCTV. The LCTV image is projected onto, and modulated by the second LCLV.
    Type: Grant
    Filed: March 3, 1995
    Date of Patent: September 2, 1997
    Inventors: Walter B. Miller, Jennifer C. Ricklin, Mikhail A. Vorontsov