Utilizing Reversal In Sign Of Dielectric Anisotropy Patents (Class 349/170)
  • Patent number: 12123255
    Abstract: A dual-mode switchable liquid-crystal window can control both radiant energy flow and privacy. The modes are selected by using different voltage frequencies. A dichroic dye is doped to enable modulation of transmission of the window. In the absence of an applied voltage, the window is transparent without haze. When a high-frequency (e.g., 1 kHz) voltage is applied, the liquid crystal and doped dye molecules inside the window reorient uniformly under dielectric interactions. The material becomes optically absorbing. The transmittance decreases, but the haze does not change. In this mode, the window can control radiant energy flow through the window. When a low-frequency (50 Hz) voltage is applied, the liquid crystal and doped dye molecules are switched into a micron-sized polydomain structure under flexoelectric interactions. The material becomes optically scattering and absorbing. The scenery behind the window is blocked. In this mode, privacy can be controlled.
    Type: Grant
    Filed: November 1, 2021
    Date of Patent: October 22, 2024
    Assignee: KENT STATE UNIVERSITY
    Inventors: Yingfei Jiang, Deng-Ke Yang, Yunho Shin
  • Patent number: 8294645
    Abstract: The invention provides a liquid crystal device and method thereof. Subsequent to applying a first electrical voltage on a liquid crystal to induce a reorientation of the liquid crystal, a second electrical voltage with proper polarity is applied on the liquid crystal to assist the relaxation of the reorientation that was induced by the first electrical voltage. The “switch-off” phase of the liquid crystal can therefore be accelerated or temporally shortened, and the device can exhibit better performance such as fast response to on/off signals. The invention can be widely used LCD, LC shutter, LC lens, spatial light modulator, telecommunication device, tunable filter, beam steering device, and electrically driven LC device, among others.
    Type: Grant
    Filed: March 12, 2009
    Date of Patent: October 23, 2012
    Assignee: Kent State University
    Inventors: Sergij V. Shiyanovskii, Mingxia Gu, Oleg D. Lavrentovich
  • Patent number: 7826019
    Abstract: The present invention provides a liquid crystal display device using nematic liquid crystal material with low power consumption and having a memory characteristic which can be easily fabricated with a high yield. The liquid crystal device using nematic liquid crystal material includes: a pair of substrates (1,4) with plate-like electrode layers (2,5) thereon; a liquid crystal layer interposed between the pair of substrates (1,4); and alignment layers (3,6) arranged between the liquid crystal layer and at least one of the pair of substrates (1,4). The alignment layers (3,6) include a plurality of different alignment domains having a substantially vertical direction and substantially horizontal direction to the surface of the substrate. Both of two orientation states, i.e. a substantially vertical orientation state and a substantially horizontal orientation state of the liquid crystal, are stable and have a memory characteristic in the absence of an electric field.
    Type: Grant
    Filed: August 14, 2006
    Date of Patent: November 2, 2010
    Assignee: Japan Science and Technology Agency
    Inventors: Makoto Yoneya, Hiroshi Yokoyama
  • Patent number: 7692731
    Abstract: A new way of generating electrical power by changing the dielectric properties of liquid crystals by mechanical means is described. Such a method and device take advantage of the nature of the liquid crystal as the dielectric material in a capacitor. A broad range of materials, including various liquid crystalline materials, as well as additional mechanisms (flexoelectric polarization) to fully exploit the potential of this mechanism may be realized. Applications of this technology may be useful in wearable personal electric generators as well as in noise damping materials/devices, which not only absorb and dissipate sound, but use it to generate electric power.
    Type: Grant
    Filed: November 9, 2005
    Date of Patent: April 6, 2010
    Assignee: Kent State University
    Inventors: Peter Palffy-Muhoray, Antal Jakli, Bahman Taheri
  • Patent number: 7643124
    Abstract: A liquid crystal is provided, which can be used in a liquid crystal display (LCD) to provide an LCD exhibiting a good transmittance. The liquid crystal according to the invention has the following properties: (i) a dielectric anisotropy (??) ranging from about ?2.5 to about ?5; (ii) a splay elastic constant (K11) ranging from about 1.1×10?11 N to about 1.6×10?11 N; (iii) a bend elastic constant (K33) ranging from about 1.1×10?11 N to about 1.6×10?11 N; and (iv) ??, K11 (N) and K33 (N) conforming to the following equation: K 11 + K 33 ? 10 × ? ? ? ? ? < 1.28 × 10 - 12 . A liquid crystal material combination is also provided which comprises the liquid crystal according to the invention above mentioned and a polymerizable monomer.
    Type: Grant
    Filed: January 23, 2008
    Date of Patent: January 5, 2010
    Assignee: AU Optronics Corp.
    Inventors: Chia-Hsuan Pai, Chao-Yuan Chen, Te-Sheng Chen, Jenn-Jia Su
  • Publication number: 20090279033
    Abstract: The present invention provides a liquid crystal display device using nematic liquid crystal material with low power consumption and having a memory characteristic which can be easily fabricated with a high yield. The liquid crystal device using nematic liquid crystal material includes: a pair of substrates (1,4) with plate-like electrode layers (2,5) thereon; a liquid crystal layer interposed between the pair of substrates (1,4); and alignment layers (3,6) arranged between the liquid crystal layer and at least one of the pair of substrates (1,4). The alignment layers (3,6) include a plurality of different alignment domains having a substantially vertical direction and substantially horizontal direction to the surface of the substrate. Both of two orientation states, i.e. a substantially vertical orientation state and a substantially horizontal orientation state of the liquid crystal, are stable and have a memory characteristic in the absence of an electric field.
    Type: Application
    Filed: August 14, 2006
    Publication date: November 12, 2009
    Applicant: Japan Science and Technology
    Inventors: Makoto Yoneya, Hiroshi Yokoyama
  • Patent number: 7550094
    Abstract: A liquid crystal device including a first electrode substrate, a second electrode substrate and a liquid crystal layer is provided. The liquid crystal layer is disposed between the first electrode substrate and the second electrode substrate. The liquid crystal layer comprises liquid crystal molecules and particles. The liquid crystal molecules are vertically aligned when the applied voltage between the first electrode substrate and the second electrode substrate is less than a threshold voltage. The arrangement of the liquid crystal molecules is changed so as to produce optical changes in the liquid crystal device when the applied voltage between the first electrode substrate and the second electrode substrate is not less than the threshold voltage.
    Type: Grant
    Filed: July 31, 2007
    Date of Patent: June 23, 2009
    Assignee: Industrial Technology Research Institute
    Inventors: Shie-Chang Jeng, Hsing-Lung Wang, Chi-Chang Liao
  • Patent number: 7463329
    Abstract: Recent theoretical investigations have predicted the existence of axially frozen modes that arise when light is incident upon an anisotropic two-dimensional photonic crystal. Such electromagnetic modes are of interest since they suggest a near-zero group velocity with extraordinary amplitudes. The present invention addresses the crystal physics associated with realizing such effects and provides for the development of materials suitable for use in the forming photonic crystals that can exhibit such effects.
    Type: Grant
    Filed: January 20, 2006
    Date of Patent: December 9, 2008
    Assignees: Clemson University, United States of America as represented by the Secretary of the Army
    Inventors: Arthur Ballato, John Ballato
  • Publication number: 20080204646
    Abstract: An in-plane switching (IPS) mode liquid crystal display (LCD) device, comprising: a first substrate and a second substrate; gate lines and data lines formed on the first substrate and crossing each other to form unit pixel regions; a switching device formed at each crossing of the gate lines and the data lines; at least one common electrode and pixel electrode arranged horizontally on the first substrate and generating a horizontal electric field; and a liquid crystal layer formed between the first substrate and the second substrate, wherein when a maximum voltage is applied to the at least one common electrode and pixel electrode, a maximum twist angle between liquid crystal molecules constituting the liquid crystal layer is about 90°. Also, the liquid crystal molecules forming the liquid crystal layer include a liquid crystal molecule having a positive dielectric anisotropy and a liquid crystal molecule having a negative dielectric anisotropy.
    Type: Application
    Filed: June 29, 2006
    Publication date: August 28, 2008
    Applicant: LG.Philips LCD CO., Ltd.
    Inventor: Young-Nam Lim
  • Patent number: 7342632
    Abstract: A display element of the present invention includes: a pair of substrates at least one of which is transparent; a medium layer, made of a medium sandwiched between the substrates 1 and 2, whose magnitude of an optical anisotropy is changed by applying an electric field; and at least a pair of electrodes applying to the medium layer an electric field which is substantially parallel to the substrates. The electrodes are provided above the substrate via insulating layers each of which is formed in a convex shape. Therefore, a maximal electric field region generated by the electrodes is separated from interfaces of the substrates.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: March 11, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Miyachi, Seiji Shibahara, Iichiro Inoue, Akihito Jinda, Takako Koide, Kiyoshi Ogishima
  • Patent number: 7327433
    Abstract: Each of a pair of substrates respectively comprises an electrode and a rubbed alignment film on one surface, while the other surface is provided with a polarizer. The substrates are placed so that the surfaces provided with the alignment films are opposed to each other, and the area between the substrates is filled with a medium to form a material layer. Then, a medium made of a negative-type liquid crystalline compound sing a photopolymerizable monomer and a polymerization initiator is injected into the material layer held between the substrates. Further, ultra violet irradiation is performed with the medium exhibiting a liquid crystal phase, so that the photopolymerized monomer is polymerized, thus forming a polymer chain. In this manner, obtained is a display element, that causes change in degree of optical anisotropy in response to application of electric (external) field, which display element can be driven by a lower intensity electric (external) field.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: February 5, 2008
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Miyachi, Seiji Shibahara, Iichiro Inoue, Shoichi Ishihara, Takako Koide
  • Patent number: 7307685
    Abstract: An electrode is provided on one surface of each of a pair of substrates. On the other surface of each of the substrates, a polarizer is provided. The substrates are assembled together so that their surfaces on which the electrodes are formed face each other. Then, a medium is introduced between the substrates, to form a dielectric material layer. The medium is prepared by mixing a chiral agent in a negative type liquid crystalline compound.
    Type: Grant
    Filed: January 14, 2005
    Date of Patent: December 11, 2007
    Assignee: Sharp Kabushiki Kaisha
    Inventors: Koichi Miyachi, Iichiro Inoue, Seiji Shibahara, Shoichi Ishihara
  • Patent number: 7297377
    Abstract: A liquid crystal display device having a pair of substrates, a liquid crystal layer filled between the pair of substrates and a plurality of pixel electrodes and common electrodes formed on one of the pair of substrates for supplying an electric field to the liquid crystal layer. The liquid crystal display device is configured so that a response time between a lowest brightness level and a highest brightness level is less than 16.7 ms, and the liquid crystal layer contains a range of 40% or more weight percentage to 100% or less weight percentage of a constituent component with a dielectric anisotropy of ???1.
    Type: Grant
    Filed: February 6, 2004
    Date of Patent: November 20, 2007
    Assignee: Hitachi, Ltd.
    Inventors: Hiroyuki Kagawa, Shintaro Takeda, Kotaro Araya, Sukekazu Aratani, Katsumi Kondo
  • Patent number: 5877826
    Abstract: A liquid crystal shutter and a drive waveform for controlling the same is presented by this invention. The liquid crystal shutter includes two distinct layers of liquid crystal material where one layer has a right hand twist sense and the other layer has a left hand twist sense. An electric field is selectively applied to the layers of liquid crystal material which have dual frequency properties. Accordingly, when a low frequency is applied to the liquid crystal materials they exhibit a positive dielectric anisotropy and a homeotropic texture which is substantially transparent. When a high frequency electric field is applied to the liquid crystal materials they exhibit a negative dielectric anisotropy and a planar texture which is substantially reflective. The liquid crystal material may be selected to selectively reflect predetermined spectrums of light.
    Type: Grant
    Filed: February 6, 1997
    Date of Patent: March 2, 1999
    Assignee: Kent State University
    Inventors: Deng-Ke Yang, Ming Xu
  • Patent number: 5798814
    Abstract: An improved method of driving liquid crystal optical devices utilizing a ferroelectric liquid crystal is described. A ferroelectric liquid crystal material disposed between a pair of substrates in the optical device has an apparent negative dielectric anisotropy at its operational temperatures, e.g. not higher than 40.degree. C. The liquid crystal consists of a number of layers normal to the substrates. The constituent layers consist, in turn, of liquid crystal molecules parallel to the substrates. Misalignment of the molecules yields bends in the layered structure which degrades the contrast ratio. When alternating electric field is given, the molecules are subjected to an electric torque which exerts thereon in order to force the molecules parallel to the substrate by virtue of the apparent negative dielectric anisotropy so that the bends can be removed. It was found that the absolute value of the apparent negative dielectric anisotropy increased as the driving frequency increased.
    Type: Grant
    Filed: August 14, 1996
    Date of Patent: August 25, 1998
    Assignee: Semiconductor Energy Laboratory Co., Ltd.
    Inventor: Toshimitsu Konuma