Patents by Inventor Michel Hareng
Michel Hareng 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).
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Patent number: 4430650Abstract: A process wherein certain disc-like liquid crystals, which locally undergo heating and then rapid cooling on either side of the transition temperature between two mesophases permit the liquid crystal to become diffuse with an adequate contrast to be used for display purposes. The following liquid crystals can be utilized, i.e.Type: GrantFiled: August 31, 1981Date of Patent: February 7, 1984Assignee: Thomson-CSFInventors: Jean Billard, Jean-Claude Dubois, Michel Hareng, Serge Le Berre, Jean-Noel Perbet
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Patent number: 4427997Abstract: The invention relates to planar display screens and more particularly to smectic liquid crystal screens.One of the problems of high definition display screens (approximately 100 to 1000 lines and columns) is caused by the devices for controlling the heating current on the lines. The complexity of the installation and costs limit the increase in the definition. The invention arranges the N lines of a screen into .sqroot.N groups of lines supplied at each of their ends by .sqroot.N control devices functioning sequentially, i.e. 2.sqroot.N devices in all. Moreover, each line has a diode placed between the heating resistor and the common point of the circuit.Application to the display of images transmitted in the form of a video signal for television and display peripheral equipment in teletransmission.Type: GrantFiled: December 8, 1981Date of Patent: January 24, 1984Assignee: Thomson-CSFInventors: Michel Hareng, Robert Hehlen, Serge Le Berre, Pierre Leclerc, Philippe Marcenac, Jean-Noel Perbet
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Patent number: 4413885Abstract: An electro-optical display device which comprises a twisted nematic liquid crystal layer and a photo-conducting layer. Two crossed electrode assemblies allow the liquid crystal to be made transparent at the points to be displayed. The light which passes at these points makes the photo-conductor conducting which applies the whole of the voltage to the liquid crystal and gives greater rapidity of inscription and a memory effect.Type: GrantFiled: February 11, 1980Date of Patent: November 8, 1983Assignee: Thomson-CSFInventors: Michel Hareng, Jean-Pierre Huignard, Serge Le Berre
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Patent number: 4390244Abstract: A liquid crystal visual display with a liquid crystal layer between two plates and resistive lines between one of the plates and the liquid crystal layer for heating the crystal to produce a display. The thermal diffusivity of the plate supporting the lines is below a value making possible viewing with the naked eye, for example 2.times.10.sup.-2 cm.sup.2 /s.Type: GrantFiled: July 23, 1980Date of Patent: June 28, 1983Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre, Pierre Leclerc, Jean Noel Perbet
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Patent number: 4385807Abstract: A display device having a memory making it possible to display information supplied by electric signals and to maintain this display when the signals have disappeared. In a smectic liquid crystal display cell the two plates enclosing the liquid crystal layer can be moved apart by a piezoelectric wedge so as to make the crystal diffusive throughout. Parts of this crystal are then made transparent by applying thereto a reorientation electric field by means of a set of electrodes. The device is intended for use more particularly in telephone exchanges having a device for the display of digital data transmitted on a telephone line.Type: GrantFiled: September 15, 1980Date of Patent: May 31, 1983Assignee: Thomson-CSFInventors: Jean-Noel Perbet, Michel Hareng, Serge Le Berre
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Patent number: 4365869Abstract: A device for visualizing an image on a large screen with a small projection distance, in which the image is formed by pieces on an assembly of liquid crystal cells for then projecting it onto a visualization screen by means of an assembly of lenses associated with the liquid crystal cells; to illuminate the cells a transparent plate is used forming a light-guide and which comprises an assembly of networks associated with the cells to extract the light from the plate and project it onto the cells.Type: GrantFiled: February 11, 1980Date of Patent: December 28, 1982Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre
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Patent number: 4334735Abstract: The invention provides a liquid crystal imaging system which employs a transitory thermo-optic effect to permit notably the reproduction of T.V. images. This transitory effect is characterized by the fleeting appearance of scattering cybotactic zones in the transparent liquid phase of a mesomorphic material, at the very beginning of the transition to a nematic transparent ordered phase. The duration of the scattering period can be considerably shortened by subjecting the mesomorphic material layer to the action of an alternating electrical field.Type: GrantFiled: January 18, 1978Date of Patent: June 15, 1982Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre
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Patent number: 4334734Abstract: This invention relates to an optical apparatus for the reproduction of images, comprising an optical modulator formed by a nematic liquid crystal cell the length of which is at least equal to the width of the paper to be printed, comprising on an inner surface N electrodes corresponding to the N points forming a line and a counter electrode on the other surface, this cell being placed between two polarizers. The modulator produces or does not produce extinction of the radiation for each point, depending on whether a voltage is not or is applied between the counter electrode and the electrode corresponding to the point which is to be reproduced. The light-sensitive paper travels against the second polariser and is printed by a line of light modulated spatially along the N points. To ensure that the optical modulator thus produced functions satisfactorily, the light source should flash on when the liquid crystal has reached a stable state, i.e.Type: GrantFiled: October 26, 1979Date of Patent: June 15, 1982Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre
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Patent number: 4333709Abstract: A mixture of liquid crystals having a mesophase of the disc-like with wires-type, where a sensitivity to the electrical field can be observed and application can be made to visual display cells. The mixture comprises two hexasubstituted triphenylene derivatives, to the nucleus of which are fixed six identical radicals in positions 2, 3, 6, 7, 10 and 11, which can be alkyl, alkoxy, alkylcarboxylate, alkylbenzoate, and alkoxybenzoate radicals. The electro-optical devices can either be of the variable birefringence type when the liquid crystal molecules have their optical axes parallel to one another and to the walls of a display cell, or of the type with a variable rotatory power under the action of an electrical field when a helical type arrangement is used, or finally, under the effect of a relatively strong field, of the type with dynamic light diffusion.Type: GrantFiled: December 3, 1980Date of Patent: June 8, 1982Assignee: Thomson-CSFInventors: Jean-Claude Dubois, Annie Zann, Jean Billard, Michel Hareng
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Patent number: 4310858Abstract: A telecopying process and a transmitter-receiver telecopier employing this process. A cell having a smectic liquid crystal is used for recording by thermo-optically forming an intermediate image of a linear element (column portion or a whole line) of the transmitted document, which image is thereafter projected onto a photosensitive surface. The same optical system permits, when transmitting, the reading of this linear element by a mosaic of detectors and, when receiving, the projection onto the photosensitive surface of the intermediate image recorded in the cell.Type: GrantFiled: August 1, 1979Date of Patent: January 12, 1982Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre, Pierre Leclerc
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Patent number: 4288822Abstract: A system comprising means for emitting an analysis beam and a recording beam, the two beams being deflected by common deflection means. The analysis beam scans the document carrying the image to be analyzed and a detecting photocell provides an electrical signal. The recording beam scans a liquid crystal cell, where it records the image in synchronism with analysis in dependence upon a modulation of the thermo-optical effects induced in the liquid crystal. This modulation is provided by the electrical signal.Type: GrantFiled: March 21, 1980Date of Patent: September 8, 1981Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre, Pierre Leclerc
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Patent number: 4277145Abstract: In a liquid-crystal display device, a smectic liquid-crystal layer and a layer of photoconductive material are placed between two transparent plates. A voltage is applied to the photoconductor by means of electrodes while scanning the photoconductor with a writing light beam. At locations in which the resistance of the photoconductor is reduced under the action of the light beam, the heat generated causes transition of the liquid crystal to the isotropic state. The light-scattering action produced by subsequent cooling of the liquid crystal has the effect of writing the image to be displayed.Type: GrantFiled: December 17, 1979Date of Patent: July 7, 1981Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre, Pierre Leclerc
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Patent number: 4222636Abstract: The present invention relates to a liquid crystal mixture exhibiting a very short turn-on time of electrically controlled optical phenomena, such as the variation in double-refraction. Said mixture comprises two liquid crystal elements having dielectric anisotropy values chosen to be almost the same but of opposite sign; the value of the resultant dielectric anisotropy is very small.Type: GrantFiled: March 17, 1978Date of Patent: September 16, 1980Assignee: Thomson-CSFInventors: Georges Assouline, Michel Hareng, Eugene Leiba
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Patent number: 4202010Abstract: A device for displaying a television video signal comprising a liquid-crystal layer inserted between two substrates. A plurality of heating lines deposited onto one substrate heats successively the layer up to an erasure temperature. A plurality of columns apply to the liquid crystal layer during the cooling of each line, samples of a video signal representing the image to be displayed. The lines of the image are thus recorded one after the other and all the dots of one line are simultaneously recorded thus allowing the layer to be heated and cooled along one line during the duration of one TV line scan.Type: GrantFiled: May 2, 1978Date of Patent: May 6, 1980Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre
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Patent number: 4196974Abstract: The invention provides a liquid crystal display cell in which particles having a preferential light absorption direction, particles which may be the molecules of a dichroic pigment, are inserted in the body of a layer of a mesomorphic material in a smectic state. The write-in can be made by a thermo-optical process. The molecular orientation of the smectic material controls the particles orientation, so that the variation in the light scattering coefficient commonly used with smectic layers are replaced by variations in the absorption coefficient, easier to use and provide a better contrast.Type: GrantFiled: November 29, 1977Date of Patent: April 8, 1980Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre
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Patent number: 4173757Abstract: This invention provides a nematic liquid crystal display device for displaying a first information in the absence of any control voltage and substituting for that another information, or successively several other informations, by application of a control voltage. Several embodiments are described, in which either rotatory polarization effect in twisted structures or dynamic scattering effect are used.Type: GrantFiled: September 21, 1977Date of Patent: November 6, 1979Assignee: Thomson-CSFInventors: Michel Hareng, Robert Hehlen, Serge Le Berre
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Patent number: 4150396Abstract: The invention provides an optical display device, utilizing a thermo-optical effect to inscribe a transmitted image in a layer of a material exhibiting a smectic state. Recording of the image with a full range of half tones without modulation of the recording beam and quick erasure of the recorded image without reheating of the film can be obtained by directly applying, simultaneously to the whole of the film either the video signal or an erasure voltage of suitable values. By associating this display device to a projection device utilizing a very bright source, the image thus recorded can be projected onto a large screen or a photosensitive substrate.Type: GrantFiled: March 3, 1977Date of Patent: April 17, 1979Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre, Erich Spitz
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Patent number: 4099857Abstract: The invention provides a liquid crystal imaging system which employs a transitory thermo-optic effect to permit notably the reproduction of T.V. images. This transitory effect is characterized by the fleeting appearance of scattering cybotactic zones in the transparent liquid phase of a mesomorphic material, at the very beginning of the transition to a nematic transparent ordered phase. The duration of the scattering period can be considerably shortened by subjecting the mesomorphic material layer to the action of an alternating electrical field.Type: GrantFiled: November 18, 1975Date of Patent: July 11, 1978Assignee: Thomson-CSFInventors: Michel Hareng, Serge Le Berre
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Patent number: 4097142Abstract: This invention relates to apparatus for automatically tracing patterns under the control of a program recorded in a computer. Said apparatus comprises means for initially recording the pattern in a liquid crystal cell by a known method under the control of said computer, and means for projecting the pattern thus recorded onto a photosensitive surface which records it on a reduced scale. It may also be projected on a large scale onto a monitor screen.Type: GrantFiled: December 14, 1976Date of Patent: June 27, 1978Assignee: Thomson-CSFInventors: Paul Cyril Moutou, Michel Hareng, Serge Le Berre
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Patent number: 4088400Abstract: An improvement in electro-optical display devices utilizing polarized light is disclosed, in which the linearly polarized light emerging from the display device is picked up by a diffuser and reaches the observer eyes after passing through a linear polarizer. The contrast is thus enhanced and the display can be used in presence of strong ambient lighting. The contrast can be still further improved by arranging at either side of the diffuser two suitably oriented quarter-wave plates.Type: GrantFiled: December 21, 1973Date of Patent: May 9, 1978Assignee: Thomson-CSFInventors: Georges Assouline, Michel Hareng, Michel Roncillat, Eugene Leiba