GB823404A - Improvements in motion picture projection apparatus - Google Patents

Improvements in motion picture projection apparatus

Info

Publication number
GB823404A
GB823404A GB2172156A GB2172156A GB823404A GB 823404 A GB823404 A GB 823404A GB 2172156 A GB2172156 A GB 2172156A GB 2172156 A GB2172156 A GB 2172156A GB 823404 A GB823404 A GB 823404A
Authority
GB
United Kingdom
Prior art keywords
winding
transformer
transistor
valve
anode
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.)
Expired
Application number
GB2172156A
Inventor
Thomas Robinson
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.)
Essoldomatic Ltd
Original Assignee
Essoldomatic Ltd
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 Essoldomatic Ltd filed Critical Essoldomatic Ltd
Priority to GB2172156A priority Critical patent/GB823404A/en
Publication of GB823404A publication Critical patent/GB823404A/en
Expired 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
    • G03B21/14—Details
    • G03B21/53—Means for automatic focusing, e.g. to compensate thermal effects

Landscapes

  • Physics & Mathematics (AREA)
  • General Physics & Mathematics (AREA)
  • Video Image Reproduction Devices For Color Tv Systems (AREA)
  • Projection Apparatus (AREA)

Abstract

823,404. Electric correspondence control systems. ESSOLDOMATIC Ltd. Oct. 10, 1957 [July 13, 1956], No. 21721/56. Class 40 (1). [Also in Group XL (b)] In a cinematograph projector, buckling of the film 1 due to heat is adapted to vary the amount of light from an auxiliary source S reflected on to a photo-transistor 6, thereby varying the value of positive voltage pulses produced by the rectifying action of the transistor 6 upon current derived from the secondary winding of a transformer T, the pulses being applied to the grid 7 of a gas-filled triode V to control the instant of striking of the valve V in each positive half-cycle of energization of its anode circuit by the secondary winding of the transformer T, the anode current pulses so produced in the valve V being passed through a winding 13 on a movable magnetic core 12 which by a mechanical linkage displaces the projector lens to adjust the forcus in accordance with the extent of film buckle. The winding 13 acts in opposition to a D.C. energized fixed coil 9. A winding 11 on the core 12 in series with the transistor 6 assists in stabilizing the operation of the apparatus. The grid 7 is biased in phase opposition to the voltage applied to the anode of the valve V by a connection on the secondary of the transformer T.
GB2172156A 1956-07-13 1956-07-13 Improvements in motion picture projection apparatus Expired GB823404A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
GB2172156A GB823404A (en) 1956-07-13 1956-07-13 Improvements in motion picture projection apparatus

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
GB2172156A GB823404A (en) 1956-07-13 1956-07-13 Improvements in motion picture projection apparatus

Publications (1)

Publication Number Publication Date
GB823404A true GB823404A (en) 1959-11-11

Family

ID=10167728

Family Applications (1)

Application Number Title Priority Date Filing Date
GB2172156A Expired GB823404A (en) 1956-07-13 1956-07-13 Improvements in motion picture projection apparatus

Country Status (1)

Country Link
GB (1) GB823404A (en)

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3205766A (en) * 1962-06-18 1965-09-14 Eastman Kodak Co Control apparatus
US3249001A (en) * 1963-06-10 1966-05-03 Honeywell Inc Automatic focusing photographic projector
US3249006A (en) * 1964-04-14 1966-05-03 Honeywell Inc Automatic focusing photographic projector
US3249007A (en) * 1964-03-26 1966-05-03 Honeywell Inc Automatic focusing photographic projector
US3264935A (en) * 1964-01-06 1966-08-09 Robert W Vose Self-focusing slide projector
US3337287A (en) * 1964-03-09 1967-08-22 Cinerama Inc Projection system
US3471225A (en) * 1966-12-05 1969-10-07 Eastman Kodak Co Automatic focusing motion picture projector

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US3205766A (en) * 1962-06-18 1965-09-14 Eastman Kodak Co Control apparatus
US3249001A (en) * 1963-06-10 1966-05-03 Honeywell Inc Automatic focusing photographic projector
US3264935A (en) * 1964-01-06 1966-08-09 Robert W Vose Self-focusing slide projector
US3337287A (en) * 1964-03-09 1967-08-22 Cinerama Inc Projection system
US3249007A (en) * 1964-03-26 1966-05-03 Honeywell Inc Automatic focusing photographic projector
US3249006A (en) * 1964-04-14 1966-05-03 Honeywell Inc Automatic focusing photographic projector
US3471225A (en) * 1966-12-05 1969-10-07 Eastman Kodak Co Automatic focusing motion picture projector

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