FR2285629A1 - Projection system using readily available items - uses liquid crystal layer with electrodes for light beam modulation - Google Patents

Projection system using readily available items - uses liquid crystal layer with electrodes for light beam modulation

Info

Publication number
FR2285629A1
FR2285629A1 FR7431323A FR7431323A FR2285629A1 FR 2285629 A1 FR2285629 A1 FR 2285629A1 FR 7431323 A FR7431323 A FR 7431323A FR 7431323 A FR7431323 A FR 7431323A FR 2285629 A1 FR2285629 A1 FR 2285629A1
Authority
FR
France
Prior art keywords
liquid crystal
crystal layer
projection system
electrodes
light beam
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
FR7431323A
Other languages
French (fr)
Other versions
FR2285629B1 (en
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
3M Co
Original Assignee
Minnesota Mining and Manufacturing Co
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Minnesota Mining and Manufacturing Co filed Critical Minnesota Mining and Manufacturing Co
Priority to FR7431323A priority Critical patent/FR2285629A1/en
Publication of FR2285629A1 publication Critical patent/FR2285629A1/en
Application granted granted Critical
Publication of FR2285629B1 publication Critical patent/FR2285629B1/fr
Granted legal-status Critical Current

Links

Classifications

    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03B—APPARATUS OR ARRANGEMENTS FOR TAKING PHOTOGRAPHS OR FOR PROJECTING OR VIEWING THEM; APPARATUS OR ARRANGEMENTS EMPLOYING ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ACCESSORIES THEREFOR
    • G03B21/00—Projectors or projection-type viewers; Accessories therefor
    • G03B21/132—Overhead projectors, i.e. capable of projecting hand-writing or drawing during action
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/135—Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied
    • G—PHYSICS
    • G02—OPTICS
    • G02F—OPTICAL DEVICES OR ARRANGEMENTS FOR THE CONTROL OF LIGHT BY MODIFICATION OF THE OPTICAL PROPERTIES OF THE MEDIA OF THE ELEMENTS INVOLVED THEREIN; NON-LINEAR OPTICS; FREQUENCY-CHANGING OF LIGHT; OPTICAL LOGIC ELEMENTS; OPTICAL ANALOGUE/DIGITAL CONVERTERS
    • G02F1/00—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics
    • G02F1/01—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour 
    • G02F1/13—Devices or arrangements for the control of the intensity, colour, phase, polarisation or direction of light arriving from an independent light source, e.g. switching, gating or modulating; Non-linear optics for the control of the intensity, phase, polarisation or colour  based on liquid crystals, e.g. single liquid crystal display cells
    • G02F1/133—Constructional arrangements; Operation of liquid crystal cells; Circuit arrangements
    • G02F1/135—Liquid crystal cells structurally associated with a photoconducting or a ferro-electric layer, the properties of which can be optically or electrically varied
    • G02F1/1352—Light-reflecting layers

Landscapes

  • Physics & Mathematics (AREA)
  • Nonlinear Science (AREA)
  • General Physics & Mathematics (AREA)
  • Mathematical Physics (AREA)
  • Chemical & Material Sciences (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Optics & Photonics (AREA)
  • Liquid Crystal (AREA)

Abstract

The projection system comprises a light source, a condenser and an optical system projecting and focussing the beam from the source on a screen. A modulator between the condenser and the projection head modulates the beam. The modulator consists of a thin liquid crystal layer between a transparent upper surface with at least one conducting surface in contact with the layer, and a lower plate with conducting surface areas opposite the above and in contact with the other surface of the layer. A voltage source generates a potential difference between the selected opposite conducting surfaces at a greater value than the liquid crystal threshold voltage.
FR7431323A 1974-09-17 1974-09-17 Projection system using readily available items - uses liquid crystal layer with electrodes for light beam modulation Granted FR2285629A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7431323A FR2285629A1 (en) 1974-09-17 1974-09-17 Projection system using readily available items - uses liquid crystal layer with electrodes for light beam modulation

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7431323A FR2285629A1 (en) 1974-09-17 1974-09-17 Projection system using readily available items - uses liquid crystal layer with electrodes for light beam modulation

Publications (2)

Publication Number Publication Date
FR2285629A1 true FR2285629A1 (en) 1976-04-16
FR2285629B1 FR2285629B1 (en) 1978-06-09

Family

ID=9143142

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7431323A Granted FR2285629A1 (en) 1974-09-17 1974-09-17 Projection system using readily available items - uses liquid crystal layer with electrodes for light beam modulation

Country Status (1)

Country Link
FR (1) FR2285629A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2380576A1 (en) * 1977-02-15 1978-09-08 Raymond Joel Reproduction and recording material marking - uses liq. crystal partially to block illumination falling on recording medium
FR2559923A1 (en) * 1984-02-22 1985-08-23 Commissariat Energie Atomique System for the projection with commentary of transparent documents or slides onto a wall screen
FR2696875A1 (en) * 1992-10-13 1994-04-15 Thomson Csf Infra-red to visible light image conversion appts. - uses pyro-electric detection connected to opto-electronic liquid crystal display.

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2380576A1 (en) * 1977-02-15 1978-09-08 Raymond Joel Reproduction and recording material marking - uses liq. crystal partially to block illumination falling on recording medium
FR2559923A1 (en) * 1984-02-22 1985-08-23 Commissariat Energie Atomique System for the projection with commentary of transparent documents or slides onto a wall screen
FR2696875A1 (en) * 1992-10-13 1994-04-15 Thomson Csf Infra-red to visible light image conversion appts. - uses pyro-electric detection connected to opto-electronic liquid crystal display.

Also Published As

Publication number Publication date
FR2285629B1 (en) 1978-06-09

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Legal Events

Date Code Title Description
ST Notification of lapse