GB823404A - Improvements in motion picture projection apparatus - Google Patents
Improvements in motion picture projection apparatusInfo
- 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
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)
- Projection Apparatus (AREA)
- Video Image Reproduction Devices For Color Tv Systems (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.
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)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3205766A (en) * | 1962-06-18 | 1965-09-14 | Eastman Kodak Co | Control apparatus |
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 |
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 |
US3471225A (en) * | 1966-12-05 | 1969-10-07 | Eastman Kodak Co | Automatic focusing motion picture projector |
-
1956
- 1956-07-13 GB GB2172156A patent/GB823404A/en not_active Expired
Cited By (7)
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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