US3779142A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic electronic flash device
Assignee: Minolta Co Ltd
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Filing: 1973-01-29
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Granted: 1973-12-18
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Expires: 1993-01-29
Abstract
Abstract An automatic electronic flash device which automatically terminates the flash illumination when a predetermined quantity of light is received from the subject being photographed. A photocell receives the light from the subject and produces a signal which is subsequently logarithmically integrated. The logarithmically integrated signal is compared with a reference signal representative of any selected one of f/stops of the camera lens aperture adjusting scale and a quench tube connected in parallel to the flash tube is fired when the integrated signal reaches the level of the reference signal. To this end, there is also provided a linkage system for connecting the lens aperture adjusting scale to a variable resistor for varying the level of the reference signal.
Inventors
- 👤 K Yata
- 👤 S Yamada
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 03:18
CPC Classifications
G; G03; G03B; G03B15/00; G03B15/02; G03B15/03; G03B15/05; G03B7/00; G03B7/16; G03B2215/00; G03B2215/05; G03B2215/0514; G03B2215/056
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
202 words
In an automatic electronic flash device, the improvement which comprises an illuminating circuit means including a flash capacitor and a flash tube for selectively artificially illuminating a subject to be photographed by means of said flash tube upon discharge of voltage stored on said flash capacitor; a light measuring circuit means responsive to an incident pulse of reflected light energy originating from said flash tube to produce an electrical signal indicative of the amount of said reflected light energy; a time integrating circuit means responsive to said electrical signal for integrating the latter and to produce an output signal; a triggering circuit means connected to said light measuring circuit means and responsive to said output signal to produce a trigger pulse when said output signal reaches a predetermined value; means for varying said predetermined value of said output signal in accordance with an information indicative of a selected one of f/stops of an lens aperture adjusting ring on the objective assembly of a photographic camera; a switch circuit means responsive to the trigger pulse for terminating the flash illumination; and coupling means for operatively coupling said lens aperture adjusting ring with said varying means to transmit said information to said varying means.
Claim 2
Dependent Claim
202 words
In an automatic electronic flash device, the improvement which comprises an illuminating circuit means including a flash capacitor and a flash tube for selectively artificially illuminating a subject to be photographed by means of said flash tube upon discharge of voltage stored on said flash capacitor; a light measuring circuit means responsive to an incident pulse of reflected light energy originating from said flash tube to produce an electrical signal indicative of the amount of said reflected light energy; a time integrating circuit means responsive to said electrical signal for integrating the latter and to produce an output signal; a triggering circuit means connected to said light measuring circuit means and responsive to said output signal to produce a trigger pulse when said output signal reaches a predetermined value; means for varying said predetermined value of said output signal in accordance with an information indicative of a selected one of f/stops of an lens aperture adjusting ring on the objective assembly of a photographic camera; a switch circuit means responsive to the trigger pulse for terminating the flash illumination; and coupling means for operatively coupling said lens aperture adjusting ring with said varying means to transmit said information to said varying means.
Claim 3
Dependent Claim
24 words
An automatic electronic flash device as claimed in claim 1, further comprising means for logarithmically suppressing said output signal from said integrating circuit means.
Claim 4
Dependent Claim
19 words
An automatic electronic flash device as claimed in claim 1, wherein said varying means comprises an electrical variable resistor.
Claim 5
Dependent Claim
91 words
An automatic electronic flash device as claimed in claim 1, wherein said varying means comprises an electrical variable resistor having a resistive element of a linear characteristic and a movable tap, and wherein said coupling means comprises a mechanical linkage system including means for detachably and operatively connecting said lens aperture adjusting ring and said variable resistor whereby rotation of the lens aperture adjusting ring causes the tap of said variable resistor to slide on the resistive element in a linear relation to said rotation of said lens aperture adjusting ring.
Claim 6
Dependent Claim
153 words
In an automatic electronic flash device for use in association with a photographic camera having an objective assembly provided with a camera lens aperture adjusting ring rotatably mounted thereon, the improvement which comprises an illuminating circuit means including a flash capacitor and a flash tube for selectively artificially illuminating a subject to be photographed by means of said flash tube upon discharge of voltage stored on said flash capacitor; a light measuring circuit means responsive to an incident pulse of reflected light energy originating from said flash tube to produce an electrical signal indicative of the amount of said reflected light energy; a time integrating circuit means responsive to said electrical signal for integrating the latter and to produce an output signal; and a triggering circuit means connected to said light measuring circuit means and responsive to said output signal to produce a trigger pulse when said output signal reaches a predetermined value.
Claim 7
Dependent Claim
153 words
In an automatic electronic flash device for use in association with a photographic camera having an objective assembly provided with a camera lens aperture adjusting ring rotatably mounted thereon, the improvement which comprises an illuminating circuit means including a flash capacitor and a flash tube for selectively artificially illuminating a subject to be photographed by means of said flash tube upon discharge of voltage stored on said flash capacitor; a light measuring circuit means responsive to an incident pulse of reflected light energy originating from said flash tube to produce an electrical signal indicative of the amount of said reflected light energy; a time integrating circuit means responsive to said electrical signal for integrating the latter and to produce an output signal; and a triggering circuit means connected to said light measuring circuit means and responsive to said output signal to produce a trigger pulse when said output signal reaches a predetermined value.
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) | 1976-12-17 | 1977-06-18 | 1977-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-17 | 1981-06-18 | 1981-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-17 | 1985-06-18 | 1985-12-18 | $7700.00 | Window Closed / Lapsed |