Patents by Inventor Philip J. Bos

Philip J. Bos 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).

  • Publication number: 20180364526
    Abstract: Liquid crystal photonic devices and microcavities filled with liquid crystal materials are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. Previous research on photo-definable alignment layers has shown that they have limited stability, particularly against subsequent light exposure. A method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer is described, along with a method of utilizing a pre-polymer infused into the microcavity mixed with the liquid crystal to provide photostability. In this method, the polymer layer, formed under optical irradiation of liquid crystal cells, is effectively localized to a thin region near the substrate surface and thus provides a significant improvement in the photostability of the liquid crystal alignment.
    Type: Application
    Filed: August 30, 2018
    Publication date: December 20, 2018
    Inventors: Valerie A. Finnemeyer, Robert K. Reich, Harry R. Clark, Carl O. Bozler, Shaun R. Berry, Philip J. Bos, Douglas R. Bryant
  • Publication number: 20160109760
    Abstract: Liquid crystal photonic devices and microcavities filled with liquid crystal materials are becoming increasingly popular. These devices often present a challenge when it comes to creating a robust alignment layer in pre-assembled cells. Previous research on photo-definable alignment layers has shown that they have limited stability, particularly against subsequent light exposure. A method of infusing a dye into a microcavity to produce an effective photo-definable alignment layer is described, along with a method of utilizing a pre-polymer infused into the microcavity mixed with the liquid crystal to provide photostability. In this method, the polymer layer, formed under optical irradiation of liquid crystal cells, is effectively localized to a thin region near the substrate surface and thus provides a significant improvement in the photostability of the liquid crystal alignment.
    Type: Application
    Filed: September 4, 2015
    Publication date: April 21, 2016
    Inventors: Valerie A. Finnemeyer, Robert K. Reich, Harry R. Clark, Carl O. Bozler, Shaun R. Berry, Philip J. Bos, Douglas R. Bryant
  • Patent number: 9261745
    Abstract: A phase retarder comprises first and second ?-cells or other tunable birefringent devices arranged optically in series. The phase retardation value of the phase retarder is a difference between the phase retardation values of the first and second ?-cells. Driving circuitry drives the phase retarder to generate a target phase retardation value by: (1) prior to a relaxation period, biasing the ?-cells to produce the target phase retardation value; (2) during the relaxation period, biasing the first ?-cell at a constant bias value; and (3) during the relaxation period, lowering the bias value of the second ?-cell continuously or stepwise to maintain the target phase retardation value for the phase retarder throughout the relaxation period. In some embodiments the operation (2) comprises applying zero bias to the first ?-cell throughout the relaxation period. In some embodiments the operation (1) comprises applying a maximum operational bias to the second ?-cell.
    Type: Grant
    Filed: May 13, 2013
    Date of Patent: February 16, 2016
    Assignee: Kent State University
    Inventors: Hsienhui Cheng, Achintya Bhowmik, Philip J. Bos
  • Publication number: 20140333875
    Abstract: A phase retarder comprises first and second ?-cells or other tunable birefringent devices arranged optically in series. The phase retardation value of the phase retarder is a difference between the phase retardation values of the first and second ?-cells. Driving circuitry drives the phase retarder to generate a target phase retardation value by: (1) prior to a relaxation period, biasing the ?-cells to produce the target phase retardation value; (2) during the relaxation period, biasing the first ?-cell at a constant bias value; and (3) during the relaxation period, lowering the bias value of the second ?-cell continuously or stepwise to maintain the target phase retardation value for the phase retarder throughout the relaxation period. In some embodiments the operation (2) comprises applying zero bias to the first ?-cell throughout the relaxation period. In some embodiments the operation (1) comprises applying a maximum operational bias to the second ?-cell.
    Type: Application
    Filed: May 13, 2013
    Publication date: November 13, 2014
    Inventors: Hsienhui CHENG, Achintya Bhowmik, Philip J. Bos
  • Patent number: 8531646
    Abstract: An electro-optical device comprises a liquid crystal material disposed in a cell and electrodes configured to bias the liquid crystal material into a generally in-plane director configuration having a non-constant spatial pattern selectable or adjustable by an in-plane component of the biasing to produce a desired refractive of diffractive optical effect.
    Type: Grant
    Filed: September 11, 2008
    Date of Patent: September 10, 2013
    Assignee: Kent State University
    Inventors: Lei Shi, Philip J. Bos, Paul F. Manamon
  • Patent number: 8300189
    Abstract: Provided is a liquid crystal (LC) device and method thereof. The device comprises (i) a body of liquid crystal, (ii) a first layer comprising a first material, and (iii) a second layer comprising a second material; wherein the first layer is located between the body of liquid crystal and the second layer; the first layer alone aligns the liquid crystal in a first orientation; the second layer alone aligns the liquid crystal in a second orientation; and the first orientation is different from the second orientation. With optimized first layer thickness, the invention can be used in sensor applications to improve detection sensitivity, and in LCD applications with enhanced control over LC pretilt transition.
    Type: Grant
    Filed: June 26, 2009
    Date of Patent: October 30, 2012
    Assignee: Kent State University
    Inventors: Ke Zhang, Philip J. Bos, Robert J. Twieg, Na Liu
  • Patent number: 8237910
    Abstract: A liquid crystal etalon includes a chiral nematic material contained in a liquid crystal cell having alignment surfaces configured to bias the chiral nematic material toward a twisted liquid crystal configuration with a twist less than 360°. Electrodes are arranged to apply an operative electrical bias to the liquid crystal cell. Mirrors disposed about the chiral nematic material define a resonant optical cavity. At a first electrical bias the etalon is transmissive for light of a first wavelength via a selected liquid crystal twist angle and cavity thickness at which different non-equal eigenmodes reach resonance conditions simultaneously. In a projector embodiment, a projection system with a field sequential image projection light source is coupled with the liquid crystal etalon, the etalon electrodes are patterned into pixels defining a display area, and the projector is operated in a field sequential illumination mode.
    Type: Grant
    Filed: April 30, 2008
    Date of Patent: August 7, 2012
    Assignee: Kent State University
    Inventors: Enkh-Amgalan Dorjgotov, Philip J. Bos, Achintya K. Bhowmik
  • Patent number: 7733452
    Abstract: The present invention relates to a liquid crystal alignment agent, a liquid crystal device produced by using the liquid crystal alignment agent thereof, and a method for alignment of liquid crystal molecules by using the liquid crystal alignment agent. In more detail, the present embodiments relates to a novel liquid crystal alignment agent used in a method of aligning liquid crystal molecules, wherein the agent includes a molecule having a highly polar functional group grafted onto an end of the molecule.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: June 8, 2010
    Assignee: Kent State University
    Inventors: Cheng Chen, Philip J. Bos, James E. Anderson
  • Publication number: 20100014037
    Abstract: Provided is a liquid crystal (LC) device and method thereof. The device comprises (i) a body of liquid crystal, (ii) a first layer comprising a first material, and (iii) a second layer comprising a second material; wherein the first layer is located between the body of liquid crystal and the second layer; the first layer alone aligns the liquid crystal in a first orientation; the second layer alone aligns the liquid crystal in a second orientation; and the first orientation is different from the second orientation. With optimized first layer thickness, the invention can be used in sensor applications to improve detection sensitivity, and in LCD applications with enhanced control over LC pretilt transition.
    Type: Application
    Filed: June 26, 2009
    Publication date: January 21, 2010
    Inventors: Ke Zhang, Philip J. Bos, Robert J. Twieg, Na Liu
  • Publication number: 20090322971
    Abstract: A liquid crystal etalon includes a chiral nematic material contained in a liquid crystal cell having alignment surfaces configured to bias the chiral nematic material toward a twisted liquid crystal configuration with a twist less than 360°. Electrodes are arranged to apply an operative electrical bias to the liquid crystal cell. Mirrors disposed about the chiral nematic material define a resonant optical cavity. At a first electrical bias the etalon is transmissive for light of a first wavelength via a selected liquid crystal twist angle and cavity thickness at which different non-equal eigenmodes reach resonance conditions simultaneously. In a projector embodiment, a projection system with a field sequential image projection light source is coupled with the liquid crystal etalon, the etalon electrodes are patterned into pixels defining a display area, and the projector is operated in a field sequential illumination mode.
    Type: Application
    Filed: April 30, 2008
    Publication date: December 31, 2009
    Inventors: Enkh-Amgalan Dorjgotov, Philip J. Bos, Achintya K. Bhowmik
  • Publication number: 20090073331
    Abstract: An electro-optical device comprises a liquid crystal material disposed in a cell and electrodes configured to bias the liquid crystal material into a generally in-plane director configuration having a non-constant spatial pattern selectable or adjustable by an in-plane component of the biasing to produce a desired refractive of diffractive optical effect.
    Type: Application
    Filed: September 11, 2008
    Publication date: March 19, 2009
    Inventors: Lei Shi, Philip J. Bos, Paul F. Manamon
  • Patent number: 6583838
    Abstract: A liquid crystal display device including a polyimide alignment layer, having a bistable liquid crystal material and a polymer stabilizer in an amount effective to stabilize the liquid crystal the liquid crystal preferably having a low or medium pretilt angle to eliminate undesired states and stripe tendency and to increase hysteresis. The device has a low driving voltage, low power consumption and fast switching.
    Type: Grant
    Filed: February 22, 2000
    Date of Patent: June 24, 2003
    Assignee: Kent State University
    Inventors: Charles D. Hoke, Philip J. Bos, Jianlin Li
  • Patent number: 6278429
    Abstract: A driving circuit for a reflective bistable cholesteric liquid crystal display which includes one substrate having a plurality of column or segment electrodes opposed by another substrate having a plurality of row or common electrodes. The intersecting column and row electrodes with the cholesteric material therebetween form a plurality of pixels. The driving circuit selectively applies a voltage to the row and column electrodes to control the appearance of the cholesteric material. In particular, the driving circuit includes at least one common driver coupled to respective common electrodes with each common driver having a first and a second common frame switch with corresponding high or low inputs. The first and second common frame switches are linked to one another by a common frame line.
    Type: Grant
    Filed: September 11, 1998
    Date of Patent: August 21, 2001
    Assignee: Kent State University
    Inventors: Jonathan C. Ruth, Richard Hewitt, Philip J. Bos
  • Patent number: 6141074
    Abstract: A liquid crystalline light modulating pixel includes first and second cell wall structures and nematic liquid crystal disposed therebetween. The first and second cell wall structures cooperate with the liquid crystal to form four liquid crystal domains within the pixel. The liquid crystal in each of the domains exhibits a twisted nematic liquid crystal structure and the orientation of the liquid crystal director of the liquid crystal adjacent one of the cell wall structures in at least two domains is different.
    Type: Grant
    Filed: December 18, 1997
    Date of Patent: October 31, 2000
    Assignee: Kent State University
    Inventors: Philip J. Bos, Hemasiri K. Vithana, David L. Johnson, Jianmin Chen
  • Patent number: 6133975
    Abstract: A liquid crystal display device including a polyimide alignment layer, having a bistable liquid crystal material and a polymer stabilizer in an amount effective to stabilize the liquid crystal, preferably about 2 weight percent, associated with the liquid crystal material, the liquid crystal having a low pretilt angle, to eliminate stripe tendency and to increase hysteresis. The device has a low driving voltage, low power consumption and fast switching.
    Type: Grant
    Filed: May 7, 1997
    Date of Patent: October 17, 2000
    Assignee: Kent State University
    Inventors: Jianlin Li, Philip J. Bos
  • Patent number: 5831700
    Abstract: A liquid crystalline light modulating pixel includes first and second cell wall structures and nematic liquid crystal within a UV cured polymer network disposed therebetween. The first and second cell wall structures cooperate with the liquid crystal to form four liquid crystal domains within the pixel. The liquid crystal in each of the domains exhibits a twisted nematic liquid crystal structure and the orientation of the liquid crystal director of the liquid crystal adjacent one of the cell wall structures in at least two domains is different. The polymer network stabilizes the four domain structure at both high field and zero field conditions.
    Type: Grant
    Filed: May 15, 1996
    Date of Patent: November 3, 1998
    Assignee: Kent State University
    Inventors: Jianlin Li, Philip J. Bos, Jianmin Chen
  • Patent number: 5825448
    Abstract: A reflective liquid crystalline diffractive light valve for use in a diffractive projection system. The liquid crystal cell includes a transparent substrate and a reflective substrate treated to provide alternating stripes which cooperate with the liquid crystal to form liquid crystal domains extending across the thickness of the cell that will produce an appropriate phase difference in light reflected by the cell, irrespective of the polarization of incident light. The techniques embodied in the present invention are applicable to the creation of electrically controllable diffractive optical elements for ray optic, integrated optic or fiber optic utilization operated in either transmission or reflection. Diffractive patterns may be lithographically, holographically or interferometrically generated.
    Type: Grant
    Filed: November 5, 1996
    Date of Patent: October 20, 1998
    Assignee: Kent State University
    Inventors: Philip J. Bos, Jianmin Chen, David L. Johnson, deceased, William E. Glenn, Carvel E. Holton, Brett E. Smith
  • Patent number: 5766694
    Abstract: A method for forming a uniformly-spaced plastic substrate liquid crystal cell (100) includes the step of forming a cell with a liquid crystal-monomer mixture (150) disposed between upper and lower plastic substrates (111, 112). The cell (100) is then exposed to ultraviolet light (170) causing the monomer to be selectively polymerized to form support walls (108) between substrates (111, 112) of the cell in the light-intense areas. The monomer may be selectively polymerized by exposing the cell (100) through a mask (180, 188). The distance between the substrates (111, 112) is maintained before the walls (108) are formed by dispersing plastic ball spacers (114) between the substrates (111, 112). During exposure to the UV light, the substrates (111, 112) are sandwiched between substantially planar supports (182, 184) to maintain contact between the substrates (111, 112) and the spacers (114) and thus a uniform distance between the substrates (111, 112).
    Type: Grant
    Filed: May 29, 1997
    Date of Patent: June 16, 1998
    Inventors: John L. West, Philip J. Bos
  • Patent number: 5748277
    Abstract: A flat-panel liquid crystal display. The display includes a flat sheet of bistable chiral nematic liquid crystal material activated by a drive circuit that individually controls the display state of multiple picture elements at a refresh rate 1000 scan lines per second. The driver circuitry activates the liquid crystal domains into homeotropic states over a relatively long activation period and then, during a short (.about.1 msec.) selection period, either keeps the domains in a homeotropic state or initiate a transition to the transient twisted planar state. The drivers then activate the domains in an evolution phase to provide either focal conic or twisted planar end states across the two-dimensional array of picture elements.
    Type: Grant
    Filed: February 17, 1995
    Date of Patent: May 5, 1998
    Assignee: Kent State University
    Inventors: Xiao-Yang Huang, Philip J. Bos, Deng-Ke Yang
  • Patent number: 5714970
    Abstract: A switchable color filter (11) includes three polarizing filters (12, 14, and 16) and two zero to substantially half-wave optical retarders (36 and 38) and is incorporated in a field sequential display system (10) to provide output states of light of three different colors to form an image in full color. Each one of four preferred embodiments (11, 11a, 11b, and 11c) of the switchable color filter provides the output states of three colors. The third and fourth preferred embodiments (11b and 11c) provide a fourth additional output state of, respectively, white light and light of a color which is a combination of two of the other output state colors. The optical retarders comprise nematic liquid crystal cells (100) having fast relaxation times to operate the display system at video rates.
    Type: Grant
    Filed: November 30, 1994
    Date of Patent: February 3, 1998
    Assignee: Tektronix, Inc.
    Inventors: Philip J. Bos, Philip A. Johnson, Jr.