GB1236257A - Photographic exposure control - Google Patents
Photographic exposure controlInfo
- Publication number
- GB1236257A GB1236257A GB4233068A GB4233068A GB1236257A GB 1236257 A GB1236257 A GB 1236257A GB 4233068 A GB4233068 A GB 4233068A GB 4233068 A GB4233068 A GB 4233068A GB 1236257 A GB1236257 A GB 1236257A
- Authority
- GB
- United Kingdom
- Prior art keywords
- scr
- capacitor
- potential
- exposure
- resistor
- 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
- G03B7/00—Control of exposure by setting shutters, diaphragms or filters, separately or conjointly
- G03B7/08—Control effected solely on the basis of the response, to the intensity of the light received by the camera, of a built-in light-sensitive device
- G03B7/081—Analogue circuits
- G03B7/083—Analogue circuits for control of exposure time
-
- 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
- G03B9/58—Means for varying duration of "open" period of shutter
Landscapes
- Physics & Mathematics (AREA)
- General Physics & Mathematics (AREA)
- Shutters For Cameras (AREA)
Abstract
1,236,257. Photographic shutter exposure control. EASTMAN KODAK CO. Sept. 5, 1968 [Sept.5, 1967], No.42330/68. Heading G2A. A shutter is opened by energization of a coil L 1 and closed by de-energization of the coil, the exposure time being determined by the light energy incident upon photo-cell PC 1 . A capacitor C 4 is charged through resistor R 11 by depression of a switch S 4 , on release of the switch to its rest position the capacitor discharges through R 4 , R 5 to ground thus causing a potential rise on the gate electrode of silicon controlled rectifier SCR 1 which is turned on to energize the coil L 1 . At the same time a negative pulse is coupled through SCR 1 and capacitor C 5 to ensure that a second silicon controlled rectifier SCR 2 is turned off. The low anode voltage of SCR 1 is coupled through resistor R 7 to the base of a transistor Q 1 which is rendered non-conducting, and the potential on capacitor C 6 rises at a rate determined by the current through voltage divider R 25 and photo-cell PC 1 . After a time delay, the potential across the capacitor C 6 reaches the firing potential of uni-junction transistor UJT, which conducts and applies a positive potential through resistor R 23 to the gate electrode of rectifier SCR 2 . The firing of SCR 2 lowers the potential on capacitor C 5 and couples a negative pulse to the anode of SCR 1 which is switched off and de-energizes solenoid L, to terminate the exposure. The exposure control system is used in the exposure of high contrast photographic film in apparatus for copying line original documents.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US66556967A | 1967-09-05 | 1967-09-05 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB1236257A true GB1236257A (en) | 1971-06-23 |
Family
ID=24670645
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB4233068A Expired GB1236257A (en) | 1967-09-05 | 1968-09-05 | Photographic exposure control |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE1797238B1 (en) |
| FR (1) | FR1580599A (en) |
| GB (1) | GB1236257A (en) |
-
1968
- 1968-08-29 FR FR1580599D patent/FR1580599A/fr not_active Expired
- 1968-09-03 DE DE19681797238 patent/DE1797238B1/en not_active Withdrawn
- 1968-09-05 GB GB4233068A patent/GB1236257A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE1797238B1 (en) | 1971-02-04 |
| FR1580599A (en) | 1969-09-05 |
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