FR2454638A1 - Variable optical diaphragm esp. for TV cameras - uses liq. crystal cells in pairs in frame controlled by coded switching circuit - Google Patents

Variable optical diaphragm esp. for TV cameras - uses liq. crystal cells in pairs in frame controlled by coded switching circuit

Info

Publication number
FR2454638A1
FR2454638A1 FR7909600A FR7909600A FR2454638A1 FR 2454638 A1 FR2454638 A1 FR 2454638A1 FR 7909600 A FR7909600 A FR 7909600A FR 7909600 A FR7909600 A FR 7909600A FR 2454638 A1 FR2454638 A1 FR 2454638A1
Authority
FR
France
Prior art keywords
pairs
switching circuit
cells
cameras
esp
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
FR7909600A
Other languages
French (fr)
Other versions
FR2454638B1 (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.)
Pierre Angenieux SA
Original Assignee
Pierre Angenieux SA
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 Pierre Angenieux SA filed Critical Pierre Angenieux SA
Priority to FR7909600A priority Critical patent/FR2454638A1/en
Publication of FR2454638A1 publication Critical patent/FR2454638A1/en
Application granted granted Critical
Publication of FR2454638B1 publication Critical patent/FR2454638B1/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
    • G03B9/00—Exposure-making shutters; Diaphragms
    • G03B9/02—Diaphragms

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Diaphragms For Cameras (AREA)
  • Liquid Crystal (AREA)

Abstract

The variable aperture optical diaphragm is for photographic equipment esp. for TV cameras. The diaphragm is based on the use of liquid crystal cells rendered opaque or transparent by electromagnetic excitation. The cells are rectangular in plan, are used in pairs (11a,11b,11c,11d) and may vary in number from one diaphragm design to another, lying linearly across the aperture or angularly displaced to provide an approximately circular aperture. The pairs of cells are positioned to each side of a square frame (11) leaving a fixed aperture at the centre. When used with a TV camera the cell group is situated between the elements of the lens. The pairs of cells are controlled by a coded switching circuit powered from a battery. Feedback from the video signal compared with a reference voltage provides the switching circuit control.
FR7909600A 1979-04-17 1979-04-17 Variable optical diaphragm esp. for TV cameras - uses liq. crystal cells in pairs in frame controlled by coded switching circuit Granted FR2454638A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
FR7909600A FR2454638A1 (en) 1979-04-17 1979-04-17 Variable optical diaphragm esp. for TV cameras - uses liq. crystal cells in pairs in frame controlled by coded switching circuit

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR7909600A FR2454638A1 (en) 1979-04-17 1979-04-17 Variable optical diaphragm esp. for TV cameras - uses liq. crystal cells in pairs in frame controlled by coded switching circuit

Publications (2)

Publication Number Publication Date
FR2454638A1 true FR2454638A1 (en) 1980-11-14
FR2454638B1 FR2454638B1 (en) 1984-12-14

Family

ID=9224378

Family Applications (1)

Application Number Title Priority Date Filing Date
FR7909600A Granted FR2454638A1 (en) 1979-04-17 1979-04-17 Variable optical diaphragm esp. for TV cameras - uses liq. crystal cells in pairs in frame controlled by coded switching circuit

Country Status (1)

Country Link
FR (1) FR2454638A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2598249A1 (en) * 1986-04-30 1987-11-06 Thomson Csf DEVICE FOR IMAGE RECONSTRUCTION BY MODULATION OF A BEAM INCIDENT OF RADIATIONS

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2329014A1 (en) * 1973-06-07 1975-01-02 Agfa Gevaert Ag PHOTOGRAPHIC CAMERA
FR2325954A1 (en) * 1975-09-26 1977-04-22 Xerox Corp Exposure control system for verographic reproducing machines - uses liquid crystal composition between two electrode surfaces, one of surfaces having several electrode elements
DE2620173A1 (en) * 1976-05-07 1977-11-10 Storz Karl Inertialess compact shutter for camera - uses liq. crystal in sections in conjunction with polarising film to block passage of light

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE2329014A1 (en) * 1973-06-07 1975-01-02 Agfa Gevaert Ag PHOTOGRAPHIC CAMERA
FR2325954A1 (en) * 1975-09-26 1977-04-22 Xerox Corp Exposure control system for verographic reproducing machines - uses liquid crystal composition between two electrode surfaces, one of surfaces having several electrode elements
DE2620173A1 (en) * 1976-05-07 1977-11-10 Storz Karl Inertialess compact shutter for camera - uses liq. crystal in sections in conjunction with polarising film to block passage of light

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
FR2598249A1 (en) * 1986-04-30 1987-11-06 Thomson Csf DEVICE FOR IMAGE RECONSTRUCTION BY MODULATION OF A BEAM INCIDENT OF RADIATIONS
EP0247912A1 (en) * 1986-04-30 1987-12-02 Thomson-Csf Image reconstruction apparatus using modulation of an incident radiation beam

Also Published As

Publication number Publication date
FR2454638B1 (en) 1984-12-14

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