US3687027A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure control circuitry for use in photographic camera
Assignee: Koparu KK
•
Filing: 1970-10-23
•
Granted: 1972-08-29
•
Expires: 1990-10-23
Abstract
Abstract An auxiliary time circuit comprising auxiliary resistors connected in series with an auxiliary capacitor is connected, in parallel, with a main time circuit comprising a photoconductive element, such as Cds, connected in series with a photometric or main capacitor. These main and auxiliary time circuits are connected, via separate diodes, respectively, with a transistorized switching circuit containing therein an electromagnet for controlling the shutter. With this arrangement, an exposure time range beyond the predetermined time range can be regulated by said auxiliary time circuit.
Inventors
- 👤 Minoru Watanabe
- 👤 Masao Takayama
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 11:15
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
213 words
An exposure control circuitry in photographic cameras, comprising a main time circuit composed of a serial circuit formed with a photoconductive element and a main capacitor, a transistorized switching circuit and an electromagnetic connected to an output terminal of said switching circuit for controlling the closing action of the shutter blades, said exposure control circuitry comprising: a first diode inserted between the juncture F of said photoconductive element and said main capacitor and one H of the input terminals of said switching circuit in such a way that said diode is arranged in the forward direction from said juncture F to said one H of the input terminals, an auxiliary time circuit comprising a serial connection of a resistor and an auxiliary capacitor and being connected in parallel with said main time circuit, and actuating said switching circuit in the case where the charge voltage of said main capacitor fails to gain the magnitude sufficient for actuating said switching circuit, and a second diode inserted between the juncture G of said resistor and said auxiliary capacitor and said one H of the input terminals of said switching circuit in such a way that this diode is arranged in the forward direction from said juncture G to said one H of the input terminals.
Claim 2
Dependent Claim
213 words
An exposure control circuitry in photographic cameras, comprising a main time circuit composed of a serial circuit formed with a photoconductive element and a main capacitor, a transistorized switching circuit and an electromagnetic connected to an output terminal of said switching circuit for controlling the closing action of the shutter blades, said exposure control circuitry comprising: a first diode inserted between the juncture F of said photoconductive element and said main capacitor and one H of the input terminals of said switching circuit in such a way that said diode is arranged in the forward direction from said juncture F to said one H of the input terminals, an auxiliary time circuit comprising a serial connection of a resistor and an auxiliary capacitor and being connected in parallel with said main time circuit, and actuating said switching circuit in the case where the charge voltage of said main capacitor fails to gain the magnitude sufficient for actuating said switching circuit, and a second diode inserted between the juncture G of said resistor and said auxiliary capacitor and said one H of the input terminals of said switching circuit in such a way that this diode is arranged in the forward direction from said juncture G to said one H of the input terminals.
Claim 3
Dependent Claim
48 words
An exposure control circuitry according to claim 1, in which said circuitry further comprises another resistor arranged in parallel with said resistor in said auxiliary circuit for regulating the limit of camera-shake, and an auxiliary switch capable of selecting its connection to either one of these two resistors.
Claim 4
Dependent Claim
32 words
An exposure control circuitry according to claim 1, in which a trigger switch is connected between said one H of the input terminals and one of the poles of the power source.
Claim 5
Dependent Claim
32 words
An exposure control circuitry according to claim 2, in which a trigger switch is connected between said one H of the input terminals and one of the poleS of the power source.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-08-29 | 1976-02-28 | 1976-08-29 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-08-29 | 1980-02-28 | 1980-08-29 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-08-29 | 1984-02-28 | 1984-08-29 | $7700.00 | Window Closed / Lapsed |