Patent US3969735A successfully refreshed from Google Patents.
US3969735A
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US
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Camera with automatic exposure-determining structure
Assignee: Pentax Corp
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Filing: 1975-03-04
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Granted: 1976-07-13
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Expires: 1995-03-04
Abstract
Abstract A camera which has the capability of automatically determining exposure of film. A light-responsive structure of the camera produces a number of pulses which is inversely proportional to light brightness while a reference pulse generating structure is capable of producing a series of reference pulses. A binary counter is connected through a switch structure to both the light-responsive structure and the reference pulse generating structure, with the switch structure first connecting the light-responsive structure to the binary counter so that the latter counts the number of pulses which is inversely proportional to light brightness. Thereafter an inverting structure which is connected to the binary counter inverts the number of pulses counted thereby, and then the switch structure disconnects the light-responsive structure from the binary counter and instead connects the reference pulse generating structure thereto so that the binary counter then counts reference pulses. The shutter is opened simultaneously with the connection of the reference pulse generating structure to the binary counter, and an automatic exposure-terminating structure detects when the number of reference pulses counted by the binary counter equals the number of pulses which were counted by the binary counter when it was connected by the switch structure to the light-responsive structure. Upon detecting this equality the exposure-terminating structure causes the shutter to be closed so that the exposure is terminated. In this way automatic exposure is capable of being determined by a digital counting structure rather than by a memory capacitor, for example. The camera further includes a blocking circuit for preventing the opening of the shutter when the number of pulses received by the counter from the light responsive structure is beyond one end of a given range and a digital diaphragm control circuit for adjusting the diaphragm when such a condition occurs.
Inventors
- 👤 Tsukumo Nobusawa
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 16:40
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/091; G03B7/095
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
325 words
In a camera, light-responsive pulse generating means for generating a number of pulses which is inversely proportional to light brightness, reference pulse generating means for generating a series of reference pulses, binary counter means for counting the pulses of both pulse generating means, switch means connected between both pulse generating means and said binary counter means for connecting said light-responsive pulse generatinng means first to said binary counter means so that the latter first counts a number of pulses inversely proportional to light brightness and for then disconnecting said light-responsive pulse generating means from said binary counter means and connecting said reference pulse generating means thereto so that after first counting the number of pulses inversely proportional to light brightness said binary counter means counts a series of reference pulses generated by said reference pulse generating means, inverting means connected to said binary counter means for inverting the number of pulses counted thereby and received from said light-responsive pulse generating means prior to counting reference pulses received from said reference pulse generating means, shutter-opening means for opening a shutter of a camera simultaneously with connecting of said reference pulse generating means to said binary counter means by said switch means so that exposure time starts with transmission of reference pulses to said binary counter means, exposure-terminating means for providing a shutter-closing signal which results in closing of the shutter and terminating an exposure, said exposure-terminating means being connected with said binary counter means for providing said signal when the number of reference pulses counted by said binary counter means equals the number of pulses received by said binary counter means from said light-responsive pulse generating means, and means for preventing opening of the shutter connected with said binary counter means to prevent operation of said shutter-opening means when the number of pulses received by said binary counter means from said light-responsive generating means is beyond at least one end of a given range of pulses.
Claim 2
Dependent Claim
325 words
In a camera, light-responsive pulse generating means for generating a number of pulses which is inversely proportional to light brightness, reference pulse generating means for generating a series of reference pulses, binary counter means for counting the pulses of both pulse generating means, switch means connected between both pulse generating means and said binary counter means for connecting said light-responsive pulse generatinng means first to said binary counter means so that the latter first counts a number of pulses inversely proportional to light brightness and for then disconnecting said light-responsive pulse generating means from said binary counter means and connecting said reference pulse generating means thereto so that after first counting the number of pulses inversely proportional to light brightness said binary counter means counts a series of reference pulses generated by said reference pulse generating means, inverting means connected to said binary counter means for inverting the number of pulses counted thereby and received from said light-responsive pulse generating means prior to counting reference pulses received from said reference pulse generating means, shutter-opening means for opening a shutter of a camera simultaneously with connecting of said reference pulse generating means to said binary counter means by said switch means so that exposure time starts with transmission of reference pulses to said binary counter means, exposure-terminating means for providing a shutter-closing signal which results in closing of the shutter and terminating an exposure, said exposure-terminating means being connected with said binary counter means for providing said signal when the number of reference pulses counted by said binary counter means equals the number of pulses received by said binary counter means from said light-responsive pulse generating means, and means for preventing opening of the shutter connected with said binary counter means to prevent operation of said shutter-opening means when the number of pulses received by said binary counter means from said light-responsive generating means is beyond at least one end of a given range of pulses.
Claim 3
Dependent Claim
25 words
The combination of claim 1 and wherein said means for preventing opening of the shutter responds to a number of pulses smaller than said range.
Claim 4
Dependent Claim
25 words
The combination of claim 1 and wherein said means for preventing opening of the shutter responds to a number of pulses greater than said range.
Claim 5
Dependent Claim
35 words
The combination of claim 1 and wherein said means for preventing opening of the shutter responds to both a number of pulses smaller than said range and a number of pulses greater than said range.
Claim 6
Dependent Claim
110 words
The combination of claim 2 and wherein the camera includes an adjustable diaphragm, and diaphragm-adjusting means operatively connected with the diaphragm for automatically stopping the latter down by a given increment when said number of pulses provided by said light-responsive pulse generating means is smaller than said range and said means for preventing opening of the shutter cooperating with said binary counter means for resetting the same so that immediately after said resetting a second operation of said light-responsive pulse generating means with the camera having its diaphragm stopped down can be carried out to determine whether with the stopped down diaphragm the number of pulses is within said range.
Claim 7
Dependent Claim
111 words
The combination of claim 3 and wherein the camera includes a diaphragm, and diaphragm adjusting means for automatically opening the diaphragm by a given increment when shutter-opening is prevented by said means for preventing opening of the shutter, the latter cooperating with said binary counter means for resetting the same so that immediately after shutter opening has been prevented because the number of pulses counted by said binary counter means and received from said light-responsive pulse generating means is greater than said range, a second counting by said binary counter means of pulses from said light-responsive pulse generating means can be carried out with a diaphragm which has a larger opening.
Claim 8
Dependent Claim
38 words
The combination of claim 6 and wherein a limiting means is operatively connected with said diaphragm adjusting means for limiting further automatic operation thereof for opening the diaphragm when the diaphragm has been opened to a given extent.
Claim 9
Dependent Claim
34 words
The combination of claim 1 and wherein an adjusting means cooperates with said binary counter means and said means for preventing opening of the shutter for adjusting at least one end of said range.
Claim 10
Dependent Claim
62 words
The combination of claim 8 and wherein said means for preventing opening of the shutter operates when the number of pulses received from said light-responsive means and counted by said binary counter means is greater than said range, and said adjusting means adjusting the longest exposure time which a given individual can provide to achieve a good photograph with a hand-held camera.
Claim 11
Dependent Claim
83 words
The combination of claim 1 and wherein an indicating means cooperates with said binary counter means for indicating when the number of pulses received from said light-responsive pulse generating means and counted by said binary counter means is greater than a given number, so that if said given number corresponds to the longest exposure time available to a given individual for making a photograph with a hand-held camera, the camera can then be placed on a tripod or the like prior to exposure.
Claim 12
Dependent Claim
161 words
In a camera, light-responsive means for providing a signal corresponding to light brightness, exposure-time determining means for automatically determining exposure time, said exposure-time determining means being connected with said light-responsive means for determining exposure time when the signal provided by said light-responsive means corresponds to a given range of light brightness, detecting means connected with said exposure-time determining means for detecting when the signal provided by said light-responsive means is beyond at least one end of said range, means connected to said detecting means for preventing opening of a shutter of the camera when said detecting means detects that the singal provided by said light-responsive means is beyond said one end of said range, and diaphragm-adjusting means connected with said detecting means for automatically adjusting a diaphragm of the camera when said detecting means detects that said signal is beyond said one end of said range, so that immediately thereafter exposure operations can be carried out with the automatically adjusted diaphragm.
Claim 13
Dependent Claim
161 words
In a camera, light-responsive means for providing a signal corresponding to light brightness, exposure-time determining means for automatically determining exposure time, said exposure-time determining means being connected with said light-responsive means for determining exposure time when the signal provided by said light-responsive means corresponds to a given range of light brightness, detecting means connected with said exposure-time determining means for detecting when the signal provided by said light-responsive means is beyond at least one end of said range, means connected to said detecting means for preventing opening of a shutter of the camera when said detecting means detects that the singal provided by said light-responsive means is beyond said one end of said range, and diaphragm-adjusting means connected with said detecting means for automatically adjusting a diaphragm of the camera when said detecting means detects that said signal is beyond said one end of said range, so that immediately thereafter exposure operations can be carried out with the automatically adjusted diaphragm.
References Cited (Backward Citations)
US3827065A
Cited
US3813680A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-07-13 | 1980-01-12 | 1980-07-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-07-13 | 1984-01-12 | 1984-07-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-07-13 | 1988-01-12 | 1988-07-13 | $7700.00 | Window Closed / Lapsed |