Automatic exposure time control for cameras
Abstract
Abstract AN APPARATUS FOR AUTOMATICALLY DETERMINING EXPOSURE TIME IN A CAMERA WHICH HAS A SHUTTER WHICH IS OPENED TO START AN EXPOSURE AND CLOSED TO TERMINATE THE EXPOSURE. A PHOTOSENSITIVE ELEMENT AND A TIMING CAPACITOR ARE CONNECTED IN SERIES TO FORM A TIMING CIRCUIT WITH THE CHARGING OF THE TIMING CAPACITOR TAKING PLACE ACCORDING TO THE INTENSITY OF LIGHT IMPINGING ON THE PHOTOSENSITIVE MEANS. A SWITCHING CIRCUIT IS TRIGGERED BY THE TRIGGER VOLTAGE WHICH FORMS THE OUTPUT OF THE TIMING CIRCUIT, AND AN AUTOMATIC SHUTTER-CLOSING MECHANISM IS ACTUATED BY THE SWITCHING CIRCUIT TO CLOSE THE SHUTTER AND TERMINATE THE EXPOSURE WHEN THE TRIGGER VOLTAGE OF THE TIMING CIRCUIT IS REACHED. THE VOLTAGE WITH WHICH THE TIMING CAPACITOR IS CHARGED CONTINUOUSLY INCREASES AS TIME ELAPSES, AND AFTER A GIVEN VOLTAGE LEVEL IS REACHED A VOLTAGE REGULATOR RESPONDS AUTOMATICALLY TO THIS LEVEL FOR REDUCING THE RATE AT WHICH THE VOLTAGE AT THE TIMING CAPACITOR INCREASES.
Inventors
- 👤 Taiichi Akiyama
Bibliographic Details
Claims Analysis
Total Claims: 0References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |