Patent US3726200A successfully refreshed from Google Patents.
US3726200A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electronic shutter for cameras
Assignee: Canon Inc
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Filing: 1970-11-18
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Granted: 1973-04-10
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Expires: 1990-11-18
Abstract
Abstract The electronic shutter for cameras incorporates a self-timer which comprises a time constant circuit and a control circuit for controlling the delayed time so that just before the completion of the action of the self-timer a warning device such as a lamp, buzzer or the like is actuated for giving the warning signal.
Inventors
- 👤 M Ogiso
- 👤 M Ishikawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 05:43
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083; G03B9/00; G03B9/58
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
123 words
An electronic shutter including a self-timer and comprising: capacitor means adapted to be energized by a power source; first resistor means for defining with said capacitor when charging, the time constant of the self-timer; second resistor means for defining with said capacitor when discharging, the time constant for an exposure; means to selectively connect said capacitor to said first and second resistors; a shutter operating mechanism; means in response to said capacitor charging to a first predetermined value for actuating said shutter operating mechanism to open the shutter and for completing the operation of the self-timer; and means in response to said capacitor discharging to a second predetermined value for actuating said shutter operating mechanism to close the shutter thereby completing an exposure.
Claim 2
Dependent Claim
123 words
An electronic shutter including a self-timer and comprising: capacitor means adapted to be energized by a power source; first resistor means for defining with said capacitor when charging, the time constant of the self-timer; second resistor means for defining with said capacitor when discharging, the time constant for an exposure; means to selectively connect said capacitor to said first and second resistors; a shutter operating mechanism; means in response to said capacitor charging to a first predetermined value for actuating said shutter operating mechanism to open the shutter and for completing the operation of the self-timer; and means in response to said capacitor discharging to a second predetermined value for actuating said shutter operating mechanism to close the shutter thereby completing an exposure.
Claim 3
Dependent Claim
21 words
An electronic shutter according to claim 1, wherein said second resistor means is a photoconductive element for automatically controlling the exposure.
Claim 4
Dependent Claim
26 words
An electronic shutter according to claim 1, wherein said first resistor means is a variable resistor capable of varying the operating time interval of the self-timer.
Claim 5
Dependent Claim
22 words
An electronic shutter according to claim 1, wherein said shutter operating mechanism includes a shutter opening mechanism and a shutter closing mechanism.
Claim 6
Dependent Claim
25 words
An electronic shutter according to claim 1, and further comprising indicating means which operates in conjunction with the completion of the operation of the self-timer.
Claim 7
Dependent Claim
49 words
An electronic shutter according to claim 3 further including reset means to reset said variable resistor to an initial set position, said reset means being responsive to the opening of the shutter after completion of the operation of the self-timer, and irrespective of the value of said variable resistor.
Claim 8
Dependent Claim
156 words
An electronic shutter including a self-timer and comprising: a capacitor means adapted to be energized by a power source; a first resistor means for defining with said capacitor when charging, the time constant of the self-timer; a second resistor means for defining with said capacitor when discharging, the time constant for an exposure; means to selectively connect said capacitor to said first and second resistors; a shutter operating mechanism; means in response to said capacitor charging to a first predetermined value for actuating said shutter operating mechanism to open the shutter and for completing the operation of the self-timer; means in response to said capacitor discharging to a second predetermined value for actuating said shutter operating mechanism to close the shutter thereby completing an exposure; detecting means for detecting a voltage across said capacitor slightly less than said first predetermined value to which said capacitor charges; and indicator means operable in response to said detected voltage.
Claim 9
Dependent Claim
156 words
An electronic shutter including a self-timer and comprising: a capacitor means adapted to be energized by a power source; a first resistor means for defining with said capacitor when charging, the time constant of the self-timer; a second resistor means for defining with said capacitor when discharging, the time constant for an exposure; means to selectively connect said capacitor to said first and second resistors; a shutter operating mechanism; means in response to said capacitor charging to a first predetermined value for actuating said shutter operating mechanism to open the shutter and for completing the operation of the self-timer; means in response to said capacitor discharging to a second predetermined value for actuating said shutter operating mechanism to close the shutter thereby completing an exposure; detecting means for detecting a voltage across said capacitor slightly less than said first predetermined value to which said capacitor charges; and indicator means operable in response to said detected voltage.
Claim 10
Dependent Claim
26 words
An electronic shutter according to claim 7, wherein said first resistor means is a variable resistor capable of varying the operating time interval of the self-timer.
Claim 11
Dependent Claim
33 words
An electronic shutter according to claim 8, further comprising an additional variable resistor adapted to be set in conjunction with said variable resistor and controlling the value of the voltage to be detected.
Claim 12
Dependent Claim
36 words
An electronic shutter according to claim 7, wherein said indicator means includes a further capacitor connected to said detecting means and wherein said indicator means is energized by a transient current flowing through said further capacitor.
References Cited (Backward Citations)
US3223013A
Cited
US3526183A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-04-09 | 1976-10-09 | 1977-04-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-09 | 1980-10-09 | 1981-04-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-09 | 1984-10-09 | 1985-04-10 | $7700.00 | Window Closed / Lapsed |