Patent US3896472A successfully refreshed from Google Patents.
US3896472A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic exposure control device for use in a photographic camera
Assignee: Minolta Co Ltd
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Filing: 1974-04-01
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Granted: 1975-07-22
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Expires: 1994-04-01
Abstract
Abstract In a photographic camera in which the diaphragm aperture for exposure is preset, and the shutter speed for the thus preset diaphragm aperture is automatically controlled with respect to the brightness of a photographic object when at the fully opened diaphragm aperture and also in accordance with the film sensitivity, an automatic exposure control device is so programmed that prior to the commencement of exposure, a determination is made whether the aforesaid automatically controlled shutter speed is higher or lower than a predetermined lower boundary value. If the shutter speed to be automatically controlled is lower than the predetermined lower boundary value, the diaphragm will be maintained in fully open position, without being set to the aforesaid predetermined diaphragm aperture, so as to automatically obtain the proper shutter speed in accordance with the brightness of a photographic object and the film sensitivity, whereby the exposure is then effected.
Inventors
- 👤 Ichiro Yoshiyama
- 👤 Kayoshi Tsujimoto
- 👤 Hiroshi Ueda
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 12:03
CPC Classifications
G; G03; G03B; G03B9/00; G03B9/02; G03B9/07; G03B7/00; G03B7/08; G03B7/081; G03B7/083
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
199 words
An automatic exposure control device for use in a photographic camera having an adjustable diaphragm aperture, comprising: diaphragm aperture adjusting means for presetting said diaphragm aperture; means for selecting the lowest shutter speed at which an exposure will not be effected by vibration of said camera; a light measuring circuit including a photoconductive element and producing outputs which vary in response to said diaphragm aperture adjusting means and said means for selecting the lowest shutter speed; detecting means for comparing the level of outputs produced by said light measuring circuit with the level set for a given output and detecting which level is higher; an electromagnet actuated in response to said detecting means; a diaphragm actuating member setting said diaphragm aperture from its fully open position to said preset diaphragm aperture prior to the commencement of exposure in association with the release operation; means for interrupting operation of said diaphragm actuating member in response to said detecting means to retain the diaphragm in its fully open position; and means for controlling the termination of exposure according to the scene light through an objective lens and the diaphragm from a photographic object to be photographed upon the commencement of exposure.
Claim 2
Dependent Claim
199 words
An automatic exposure control device for use in a photographic camera having an adjustable diaphragm aperture, comprising: diaphragm aperture adjusting means for presetting said diaphragm aperture; means for selecting the lowest shutter speed at which an exposure will not be effected by vibration of said camera; a light measuring circuit including a photoconductive element and producing outputs which vary in response to said diaphragm aperture adjusting means and said means for selecting the lowest shutter speed; detecting means for comparing the level of outputs produced by said light measuring circuit with the level set for a given output and detecting which level is higher; an electromagnet actuated in response to said detecting means; a diaphragm actuating member setting said diaphragm aperture from its fully open position to said preset diaphragm aperture prior to the commencement of exposure in association with the release operation; means for interrupting operation of said diaphragm actuating member in response to said detecting means to retain the diaphragm in its fully open position; and means for controlling the termination of exposure according to the scene light through an objective lens and the diaphragm from a photographic object to be photographed upon the commencement of exposure.
Claim 3
Dependent Claim
32 words
An automatic exposure control device as in claim 1, further comprising: means for selecting the film sensitivity; and means for changing said set level in association with said film sensitivity selecting means.
Claim 4
Dependent Claim
51 words
An automatic exposure control device as in claim 1, wherein said light measuring circuit produces the level of outputs corresponding to voltages which are applied through said photoconductive element and a variable resistor whose resistance varies in response to said diaphragm aperture adjusting means and said lowest shutter speed selecting means.
Claim 5
Dependent Claim
82 words
An automatic exposure control device as in claim 3, wherein said variable resistor consists of a sliding element and a slidable resistor, said sliding element being rigidly attached to a wire having one end fixedly secured to a member interconnected with said diaphragm aperture adjusting means, so as to interconnect with said diaphragm aperture adjusting means, and said slidable resistor being interconnected with said lowest shutter speed selecting means and being movable by said wire in contacting relation with said sliding element.
Claim 6
Dependent Claim
56 words
An automatic exposure control device as in claim 4, further comprising: a contact mounted on one terminal of said slidable resistor, said terminal being close to the side to which said wire is attached; a switch consisting of said contact and said sliding element; and an indicator element connected through said switch to a potential source.
Claim 7
Dependent Claim
104 words
An automatic exposure control device as in claim 4, further comprising: a film sensitivity selecting dial; a pulley rotatably supported in said camera and having a circumference around which is wound said wire having one end fixedly attached to the member interconnected with said diaphragm aperture adjusting means; a wire take-up shaft having a tendency of taking up the wire therearound, said wire having the other end fixedly attached to said take-up shaft; and a meter provided coaxially and integrally with said take-up shaft and rotatably mounted therewith, said meter having a pointer facing the inside of a view finder of said photographic camera.
Claim 8
Dependent Claim
85 words
An automatic exposure control device as in claim 1, further comprising: an exchangeable lens barrel mounted exchangeably on the camera body and equipped with an objective lens and said diaphragm; a diaphragm connecting ring mounted rotAtably on the camera body and adapted to interconnect with a diaphragm aperture adjusting ring provided on said exchangeable lens barrel with said exchangeable lens barrel mounted on the camera body; and connecting means for interconnecting said diaphragm actuating ring with said exchangeable lens barrel mounted on the camera body.
Claim 9
Dependent Claim
54 words
An automatic exposure control device as in claim 1, wherein said light measuring circuit further includes a second photoconductive element, said second photoconductive element controls the termination of exposure and is mounted to confront an exposure frame of the camera and astride the light path extending from the objective lens to said exposure frame.
Claim 10
Dependent Claim
68 words
An automatic exposure control device as in claim 8, wherein said second photoconductive element receives light rays of scene light of a photographic object which are reflected from a surface of the front curtain of a focal plane shutter and from the surface of a light sensitive film within said exposure frame, said scene light coming through the objective lens and the diaphragm of the exchangeable lens barrel.
Claim 11
Dependent Claim
37 words
An automatic exposure control device as in claim 1, further comprising means for warning that the lowermost shutter speed value selected requires a shutter speed impossible for the camera when the diaphragm aperture is held fully open.
Claim 12
Dependent Claim
39 words
An automatic exposure control device as in claim 10 further comprising: means for setting a preset aperture value, said setting means being coupled with said means for warning to adjust the latter in accordance with the set shutter speed.
Claim 13
Dependent Claim
63 words
An automatic exposure control device as in claim 10, wherein said means for warning includes an indicating means and a switch connected in series with each other to an electric power source, said switch including a first contact positioned in accordance with the setting of the preset aperture value and a second contact positioned in accordance with said selection of lowermost shutter speed.
Claim 14
Dependent Claim
84 words
An automatic exposure control device as in claim 12 wherein said light measuring circuit further includes a variable resistor, means coupled with said first photoconductive element to form a voltage divider therewith, and a variable resistor comprising a resistance material mounted on a support which is movable in accordance with said setting of film sensitivity, said second contact serves as a movable contact for said variable resistor, and said first contact is mounted on said support adjacent to one end of said resistance material.
References Cited (Backward Citations)
US3687026A
Cited
US3824606A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-07-21 | 1979-01-20 | 1979-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-07-21 | 1983-01-20 | 1983-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-07-21 | 1987-01-20 | 1987-07-22 | $7700.00 | Window Closed / Lapsed |