Patent US3738237A successfully refreshed from Google Patents.
US3738237A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Exposure quantity control device for camera
Assignee: Canon Inc
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Filing: 1970-11-02
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Granted: 1973-06-12
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Expires: 1990-11-02
Abstract
Abstract The disclosed exposure quantity control device for a camera, includes an exposure quantity determination circuit S and an indicating circuit I for indicating whether or not the camera is operating within an acceptable range. The inputs to said S and I circuits are formed by an output signal at a voltage dividing point of an input circuit that increases photographic information. An indication of proper or improper exposure is obtained for both EE and flash photography by said indicating circuit.
Inventors
- 👤 T Uchiyama
- 👤 T Ito
- 👤 M Matsuda
- 👤 M Ogiso
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 15:48
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
168 words
An exposure control apparatus for a camera having a flash affecting control, comprising circuit means for establishing a voltage, indicator means responsive to the voltage of said circuit means for indicating whether the voltage falls within a predetermined range, exposure control means responsive to the voltage of said circuit means for controlling the operation of the camera in response to the voltage of said circuit means, said circuit means having photosensitive means responsive to illumination and flash regulating means responsive to the setting of the flash affecting control, and switch means in said circuit means for alternately switching said photosensitive means and said flash regulator means into and out of said circuit means so that the voltage is alternately indicative of the illumination and the setting of the flash affecting control, whereby the voltage controls said indicator means and said exposure control means alternately on the basis of illumination and control setting, said indicator means including two indicating circuits operative of different levels in response to the voltage.
Claim 2
Dependent Claim
168 words
An exposure control apparatus for a camera having a flash affecting control, comprising circuit means for establishing a voltage, indicator means responsive to the voltage of said circuit means for indicating whether the voltage falls within a predetermined range, exposure control means responsive to the voltage of said circuit means for controlling the operation of the camera in response to the voltage of said circuit means, said circuit means having photosensitive means responsive to illumination and flash regulating means responsive to the setting of the flash affecting control, and switch means in said circuit means for alternately switching said photosensitive means and said flash regulator means into and out of said circuit means so that the voltage is alternately indicative of the illumination and the setting of the flash affecting control, whereby the voltage controls said indicator means and said exposure control means alternately on the basis of illumination and control setting, said indicator means including two indicating circuits operative of different levels in response to the voltage.
Claim 3
Dependent Claim
33 words
An apparatus, as in claim 1, wherein said exposure control circuit includes a triggering circuit having an electromagnet, said circuit means including a capacitor connectable for obtaining a time variation of the voltage.
Claim 4
Dependent Claim
19 words
An apparatus, as in claim 1, wherein said exposure control means includes current measuring means for determining the exposure.
Claim 5
Dependent Claim
31 words
An apparatus, as in claim 1, wherein one of said circuits operates at a level corresponding to a maximum exposure condition and the other circuit corresponding to a minimum exposure condition.
Claim 6
Dependent Claim
15 words
An apparatus, as in claim 1, wherein said circuits each includes two cascade connected amplifiers.
Claim 7
Dependent Claim
21 words
An apparatus, as in claim 1, wherein said circuits each includes a differential amplifier responsive to the voltage and an indicator.
Claim 8
Dependent Claim
17 words
An apparatus, as in claim 1, wherein said circuit means includes a resistor responding to the setting.
Claim 9
Dependent Claim
30 words
An apparatus, as in claim 1, wherein said circuits are a pair of Schmitt trigger circuits each responding to the voltage and each having different sensitivities for indicating a range.
Claim 10
Dependent Claim
28 words
An apparatus, as in claim 1, wherein said circuits are a pair of oppositely poled differential amplifiers each responsive to the voltage, and each having an indicator light.
Claim 11
Dependent Claim
29 words
An apparatus, as in claim 1, wherein the flash affecting control includes a focus control and said circuit means includes a resistor varying in response to the focus control.
Claim 12
Dependent Claim
46 words
An apparatus, as in claim 1, wherein said circuit means forms a voltage divider wherein the voltage constitutes a voltage divider tapoff, one portion of said voltage divider being composed alternately of said flash regulator means and said photosensitive means in response to said switch means.
Claim 13
Dependent Claim
46 words
An apparatus, as in claim 11, wherein said circuit means forms a voltage divider wherein the voltage constitutes a voltage divider tapoff, one portion of said voltage divider being composed alternately of said flash regulator means and said photosensitive means in response to said switch means.
Claim 14
Dependent Claim
151 words
An exposure determining apparatus for a camera, comprising exposure control means for determining the exposure value of the camera, a photoconductive cell, a resistive Element adjustable to a resistive value between upper and lower values corresponding to a distance between maximum and minimum distances to a subject to be photographed, a second element, switching means for selectively connecting the second element alternatively into effective circuit arrangement with said resistive element and said photoconductive element, said exposure control means being connected to said second element, and indicating means connected to said element for whether the exposure condition is within a predetermined exposure range both when the photoconductive cell is connected to the second element, said indicating means including two switching circuit means each coupled to the second element and each being responsive to electrical conditions at the element reaching a different level for producing separate indications when the respective levels are reached.
Claim 15
Dependent Claim
151 words
An exposure determining apparatus for a camera, comprising exposure control means for determining the exposure value of the camera, a photoconductive cell, a resistive Element adjustable to a resistive value between upper and lower values corresponding to a distance between maximum and minimum distances to a subject to be photographed, a second element, switching means for selectively connecting the second element alternatively into effective circuit arrangement with said resistive element and said photoconductive element, said exposure control means being connected to said second element, and indicating means connected to said element for whether the exposure condition is within a predetermined exposure range both when the photoconductive cell is connected to the second element, said indicating means including two switching circuit means each coupled to the second element and each being responsive to electrical conditions at the element reaching a different level for producing separate indications when the respective levels are reached.
Claim 16
Dependent Claim
38 words
An apparatus as in claim 13, wherein said exposure control means includes a triggering circuit having an electromagnet, said exposure control means including a capacitor connectable for obtaining a time variation of voltages across said second resistive element.
Claim 17
Dependent Claim
19 words
An apparatus as in claim 13, wherein said exposure control means includes current measuring means for determining the exposure.
Claim 18
Dependent Claim
19 words
An apparatus as in claim 13, wherein each of said circuit means included signalling means for producing the indications.
Claim 19
Dependent Claim
26 words
An apparatus as in claim 13, wherein said circuit means each includes two cascade connected amplifiers, one of said amplifiers being connected to said indicating means.
Claim 20
Dependent Claim
27 words
An apparatus as in claim 13, wherein said circuit means each includes a differential amplifier responsive to the input thereto and signalling means for producing the indication.
Claim 21
Dependent Claim
46 words
An apparatus as in claim 16, wherein said circuit means each includes a pair of Schmitt trigger circuits each responding to the input and each having different sensitivities for establishing a range, each of said Schmitt trigger circuits being connected to one of said signalling means.
Claim 22
Dependent Claim
44 words
An apparatus as in claim 16 wherein said circuit means each includes a pair of oppositely poled differential amplifiers each responsive to the input, each of said signalling means having an indicator light connected to one of the pair of oppositely poled differential amplifiers.
Claim 23
Dependent Claim
14 words
An apparatus as in claim 13, wherein said resistive element includes a focus control.
Claim 24
Dependent Claim
40 words
An apparatus as in claim 13, wherein said second element is resistive and said first resistive element and said photoconductive cell respectively form a voltage divider with said second resistive element when connected in circuit therewith by said switch means.
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) | 1976-06-11 | 1976-12-11 | 1977-06-12 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-11 | 1980-12-11 | 1981-06-12 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-11 | 1984-12-11 | 1985-06-12 | $7700.00 | Window Closed / Lapsed |