US3903529A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure value controlling apparatus
Assignee: Canon Inc
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Filing: 1972-12-13
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Granted: 1975-09-02
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Expires: 1992-12-13
Abstract
Abstract An electronic exposure controlling apparatus for use in cameras having a capacitor to be charged through a first resistive circuit from a voltage source in association with the depression of a shutter release. A switching circuit effects switching action when the charge of the capacitor comes to a predetermined value. A shutter of a shutter mechanism is opened in response to the switching action of the switching circuit and a switch connects the capacitor to a second resistive circuit, including a photoconductive element, in synchronism with the opening of the shutter so as to discharge the capacitor. The switching circuit actuates the closing of the shutter when the capacitor discharges to a predetermined value.
Inventors
- 👤 Kanehiro Sorimachi
- 👤 Tadashi Ito
- 👤 Mitsutoshi Ogiso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 15:02
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
234 words
In a photographic camera in which both the aperture value of the picture taking lens and the exposure period of a shutter care controlled electromagnetically, the improvement comprising in combination: a. movable means for forming the aperture of the taking lens, b. a single electronic control circuit including photoelectric detector means responsive to intensity of light incident thereon, the light intensity corresponding to intensity of light incident on a photosensitive material through the taking lens, said photoelectric detector means having an output, electromagnetic means for controlling said movable means, and a signal generator means for applying a signal to said electromagnetic means in response to the output of the photoelectric detector means, c. an exposure period presetting means for presetting a value, corresponding to the exposure period, into said single electronic control circuit, d. a starter means for releasing the movable means for the aperture value control, e. a shutter release means for releasing the shutter of the photographic camera after the completion of the controlling operation of the electromagnetic means, and f. a switching means for switching the single electronic control circuit into a condition for controlling the exposure period of the shutter device in association with the shutter release means, the single electronic control circuit controlling the exposure period of the shutter device after the aperture setting of the aperture device in response to the light intensity on the photoelectric detector means.
Claim 2
Dependent Claim
234 words
In a photographic camera in which both the aperture value of the picture taking lens and the exposure period of a shutter care controlled electromagnetically, the improvement comprising in combination: a. movable means for forming the aperture of the taking lens, b. a single electronic control circuit including photoelectric detector means responsive to intensity of light incident thereon, the light intensity corresponding to intensity of light incident on a photosensitive material through the taking lens, said photoelectric detector means having an output, electromagnetic means for controlling said movable means, and a signal generator means for applying a signal to said electromagnetic means in response to the output of the photoelectric detector means, c. an exposure period presetting means for presetting a value, corresponding to the exposure period, into said single electronic control circuit, d. a starter means for releasing the movable means for the aperture value control, e. a shutter release means for releasing the shutter of the photographic camera after the completion of the controlling operation of the electromagnetic means, and f. a switching means for switching the single electronic control circuit into a condition for controlling the exposure period of the shutter device in association with the shutter release means, the single electronic control circuit controlling the exposure period of the shutter device after the aperture setting of the aperture device in response to the light intensity on the photoelectric detector means.
Claim 3
Dependent Claim
32 words
The improvement as claimed in claim 1 wherein the shutter release means is associated with said electromagnetic means to be driven after the completion of the controlling operation of the electromagnetic means.
Claim 4
Dependent Claim
24 words
The improvement as claimed in claim 1 wherein the single electronic control circuit further includes a distance setting means for setting an object distance.
Claim 5
Dependent Claim
28 words
The improvement as claimed in claim 1 wherein an exposure period is determined corresponding to the light intensity after the aperture setting of the aperture device is performed.
Claim 6
Dependent Claim
31 words
The improvement as claimed in claim 1 wherein the aperture value control and the exposure period control are performed with the aid of a single capacitor respectively under charging and discharging.
References Cited (Backward Citations)
US3721167A
Cited
US3726200A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-09-01 | 1979-03-03 | 1979-09-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-09-01 | 1983-03-03 | 1983-09-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-09-01 | 1987-03-03 | 1987-09-02 | $7700.00 | Window Closed / Lapsed |