US3792484A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic flash control device
Assignee: Minolta Co Ltd
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Filing: 1971-05-11
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Granted: 1974-02-12
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Expires: 1991-05-11
Abstract
Abstract An automatic diaphragm aperture control device and an automatic flash control device are combined to effect termination of flash firing by adjusting a threshold level in accordance with a light measuring circuit including a first light receiving element. A second light receiving element in the diaphragm aperture control device adjusts the diaphragm aperture in accordance with the intensity of light and also adjusts the threshold for terminating flash firing in accordance with the light intensity measured by the second light receiving element.
Inventors
- 👤 K Tsujimoto
- 👤 Y Fujii
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 23:06
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/16; G03B15/00; G03B15/02; G03B15/03; G03B15/05; G03B7/087; G03B9/00; G03B9/70; G03B2215/00; G03B2215/05
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
178 words
In an apparatus for controlling exposure through cooperation of an automatic diaphragm aperture control device and an automatic flash control device, said flash control device, comprising: a light measuring circuit having a first light receiving element for generating current in response to the intensity of light incident thereon; means for integrating said current to provide an output signal; first means responsive to said output signal for terminating flash firing when said output signal reaches a predetermined level; and said diaphragm aperture control device, comprising: a second light receiving element receiving scene light; a movable member for determining the aperture size as a function of the position thereof; second means responsive to said second light receiving element for adjusting the position of said movable member in accordance with the intensity of light incident on said second light receiving element; means for restraining said movable member in response to shutter release operation; means for biasing said first responsive means to set said predetermined level; and means for adjusting said biasing means in accordance with the position of said movable member.
Claim 2
Dependent Claim
178 words
In an apparatus for controlling exposure through cooperation of an automatic diaphragm aperture control device and an automatic flash control device, said flash control device, comprising: a light measuring circuit having a first light receiving element for generating current in response to the intensity of light incident thereon; means for integrating said current to provide an output signal; first means responsive to said output signal for terminating flash firing when said output signal reaches a predetermined level; and said diaphragm aperture control device, comprising: a second light receiving element receiving scene light; a movable member for determining the aperture size as a function of the position thereof; second means responsive to said second light receiving element for adjusting the position of said movable member in accordance with the intensity of light incident on said second light receiving element; means for restraining said movable member in response to shutter release operation; means for biasing said first responsive means to set said predetermined level; and means for adjusting said biasing means in accordance with the position of said movable member.
Claim 3
Dependent Claim
38 words
Apparatus as in claim 1 wherein said second light receiving element measures the light intensity of the overall objective field and said first light receiving element measures the light intensity of a selected portion of said objective field.
Claim 4
Dependent Claim
86 words
Apparatus as in claim 1 wherein said means for biasing includes a variable resistance; said first means includes first and second transistors, said first transistor is responsive to said output signal and said variable resistance is connected to said first transistor to vary the switching level thereof, said second transistor is switched in response to the switching of said first transistor; said first means further includes means for shorting said flash device and trigger means actuated by said second transistor for energizing said means for shorting.
Claim 5
Dependent Claim
130 words
Apparatus as in claim 3 wherein said first means further includes a third transistor; said first light receiving element is connected to the base electrode of said third transistor, said means for integrating is a capacitor connected to the collector of said third transistor, the base electrode of said first transistor is connected to the collector of said third tranSistor, said variable resistance is connected to the collector of said first transistor, the base of said second transistor is connected to the collector of said first transistor, said trigger means is a silicon control rectifier with the gate thereof connected to the collector of said second transistor; said means for shorting is a discharge tube; and said flash device is a flash tube connected in parallel with said discharge tube.
Claim 6
Dependent Claim
65 words
Apparatus as in claim 3 further comprising a shutter speed setting member and a film sensitivity setting member; a ring member having mounted thereon said variable resistance; said movable member includes a contact element contacting said variable resistance; said film sensitivity setting member is connected to rotate with said ring member; and said shutter speed setting member is rotatable independently of said film sensitivity member.
Claim 7
Dependent Claim
58 words
Apparatus as in claim 5 wherein said film sensitivity setting member includes a variable slit; and said shutter speed setting member includes means for mounting said second light receiving element in alignment with said variable slit whereby the light incident on said second light receiving element varies in accordance witth the rotation of said film sensitivity setting member.
Claim 8
Dependent Claim
65 words
Apparatus as in claim 5 wherein said second means includes an exposure meter responsive to said second light receiving element and having a pointer indicating exposure conditions, means adjustable in accordance with the movement of said pointer, and said movable member includes means engaging said adjustable means whereby said movable member is rotated in accordance with the light measured by said second light receiving element.
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) | 1977-02-11 | 1977-08-13 | 1978-02-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-02-11 | 1981-08-13 | 1982-02-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-02-11 | 1985-08-13 | 1986-02-12 | $7700.00 | Window Closed / Lapsed |