US3775001A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Automatic aperture controls for motion picture cameras
Assignee: ASAHI KOGAKU KAGYO KK
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Filing: 1972-04-10
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Granted: 1973-11-27
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Expires: 1992-04-10
Abstract
Abstract A motion picture camera having automatic controls for setting the aperture. The adjustable diaphragm of the camera is controlled by a reversible adjusting structure which can move in opposed directions one of which enlarges the aperture and the other of which reduces the aperture. The reversible adjusting structure is controlled by way of automatic controls which automatically achieve an aperture which will provide proper film exposure, the controls being regulated according to a number of factors one of which is the light at the object to be photographed. This latter factor is introduced into the controls by way of a light-detecting structure which responds to light at the object and which feeds to the controls a signal in the form of an arithmetic progression, the controls also being regulated according to the speed of the film which is exposed and the rate of film movement in the camera. In addition compensating devices are provided to compensate for the condition where the camera is running and for the condition where the camera is not running.
Inventors
- 👤 S Miyakawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 03:14
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/085; G03B19/00; G03B19/18
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
238 words
In a motion picture camera, adjustable diaphragm means, reversible adjusting means operatively connected with said adjustable diaphragm means for adjusting the latter, said reversible adjusting means being operable in an apertureenlarging direction for increasing the aperture of said adjustable diaphragm means and an opposed aperture-reducing direction of operation for reducing the aperture of the adjustable diaphragm means, control means operatively connected with said reversible adjusting means for operating the latter in one or the other of said directions of operation until said reversible adjustable means places said diaphragm means in a position where proper film exposure takes place, and lightdetecting means operatively connected with said control means for detecting the condition of light at the object which is photographed and for influencing said control means to actuate said reversible adjusting means to achieve proper film exposure in accordance with light at the object which is photographed, said light-detecting means including a photosensitive means for receiving light and converting the latter into an electrical quantity and a log-conversion diode connected in series with said photosensitive means, said diode and photosensitive means being electrically coupled with said control means for influencing the latter according to the lighting conditions, a converter means being electrically connected with said control means for feeding an AC signal to the latter for terminating the operation of said reversible adjusting means precisely when said diaphragm means is in a position where proper film exposure takes place.
Claim 2
Dependent Claim
238 words
In a motion picture camera, adjustable diaphragm means, reversible adjusting means operatively connected with said adjustable diaphragm means for adjusting the latter, said reversible adjusting means being operable in an apertureenlarging direction for increasing the aperture of said adjustable diaphragm means and an opposed aperture-reducing direction of operation for reducing the aperture of the adjustable diaphragm means, control means operatively connected with said reversible adjusting means for operating the latter in one or the other of said directions of operation until said reversible adjustable means places said diaphragm means in a position where proper film exposure takes place, and lightdetecting means operatively connected with said control means for detecting the condition of light at the object which is photographed and for influencing said control means to actuate said reversible adjusting means to achieve proper film exposure in accordance with light at the object which is photographed, said light-detecting means including a photosensitive means for receiving light and converting the latter into an electrical quantity and a log-conversion diode connected in series with said photosensitive means, said diode and photosensitive means being electrically coupled with said control means for influencing the latter according to the lighting conditions, a converter means being electrically connected with said control means for feeding an AC signal to the latter for terminating the operation of said reversible adjusting means precisely when said diaphragm means is in a position where proper film exposure takes place.
Claim 3
Dependent Claim
260 words
In a motion picture camera, adjustable diaphragm means, reversible adjusting means operatively connected with said adjustable diaphragm means for adjusting the latter, said reversible adjusting means being operable in an aperture-enlarging direction for increasing the aperture of said adjustable diaPhragm means and an opposed aperture-reducing direction of operation for reducing the aperture of the adjustable diaphragm means, control means operatively connected with said reversible adjusting means for operating the latter in one or the other of said directions of operation until said reversible adjustable means places said diaphragm means in a position where proper film exposure takes place, and light-detecting means operatively connected with said control means for detecting the condition of light at the object with is photographed and for influencing said control means to actuate said reversible adjusting means to achieve proper film exposure in accordance with light at the object which is photographed, said control means including a transistor and a pair of circuits operatively connected between the latter and said reversible adjusting means for responding to the operation of said transistor for operating said reversible adjusting means in one direction or the other, a pair of potentiometers connected in parallel with each other and to said transistor for respectively controlling the latter according to the factor of the speed of film movement and the speed of the film, and a converter means operatively connected with said transistor for feeding an AC signal thereto, for terminating operation of said reversible adjusting means precisely when said diaphragm means is in a position where proper film exposure takes place.
Claim 4
Dependent Claim
260 words
In a motion picture camera, adjustable diaphragm means, reversible adjusting means operatively connected with said adjustable diaphragm means for adjusting the latter, said reversible adjusting means being operable in an aperture-enlarging direction for increasing the aperture of said adjustable diaPhragm means and an opposed aperture-reducing direction of operation for reducing the aperture of the adjustable diaphragm means, control means operatively connected with said reversible adjusting means for operating the latter in one or the other of said directions of operation until said reversible adjustable means places said diaphragm means in a position where proper film exposure takes place, and light-detecting means operatively connected with said control means for detecting the condition of light at the object with is photographed and for influencing said control means to actuate said reversible adjusting means to achieve proper film exposure in accordance with light at the object which is photographed, said control means including a transistor and a pair of circuits operatively connected between the latter and said reversible adjusting means for responding to the operation of said transistor for operating said reversible adjusting means in one direction or the other, a pair of potentiometers connected in parallel with each other and to said transistor for respectively controlling the latter according to the factor of the speed of film movement and the speed of the film, and a converter means operatively connected with said transistor for feeding an AC signal thereto, for terminating operation of said reversible adjusting means precisely when said diaphragm means is in a position where proper film exposure takes place.
Claim 5
Dependent Claim
80 words
The combination of claim 2 and wherein said control means further includes a pair of compensating resistors both connected in series with one of said potentiometers and a reversible switch means electrically connected operatively with said resistors for rendering one of said resistors operative when the camera runs and the other of said resistors operative when the camera does not run, said resistors compensating for light received while the camera is running and while the camera is not running, respectively.
Claim 6
Dependent Claim
66 words
The combination of claim 3 and wherein said light-detecting means includes a rotary shutter which reflects light after the light has passes through the diaphragm, a photosensitive element for receiving the reflected light and converting the latter into an electrical quantity and a diode connected to said photo-sensitive element and to said transistor, said photosensitive element and diode influencing said transistor according to an arithmetic progression.
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) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |