Patent US3657987A successfully refreshed from Google Patents.
US3657987A
Expired / Lapsed
US
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Self-balancing apparatus for photographic cameras
Assignee: Eastman Kodak Co
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Filing: 1970-10-27
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Granted: 1972-04-25
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Expires: 1990-10-27
Abstract
Abstract A self-balancing exposure control apparatus is disclosed which includes a diaphragm defining a first aperture disposed in a cooperative relation with a camera lens and a second aperture disposed in a cooperative relation with a photosensitive device having a parameter which varies as a function of incident illumination. The apparatus includes a control circuit which responds to variations in the parameter to move the diaphragm to adjust the effective size of the respective apertures to return the level of illumination incident on the photosensitive device to a predetermined level wherein the circuit is balanced and pass sufficient light to the camera lens for suitable film exposure. With decreasing scene brightness, the control circuit causes the diaphragm to increase the effective size of both apertures until the camera lens aperture reaches a size which corresponds to the maximum light transmitting capability of the camera lens. If the scene brightness continues to decrease, the size of the camera lens aperture will be maintained at the maximum size while the photosensitive device aperture will continue to increase in size to return the illumination incident on the photosensitive device to the predetermined illumination level.
Inventors
- 👤 David L Babcock
- 👤 David B Lederer
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 20:45
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/085
Claims Analysis
Total Claims: 28
Claim 1
Independent Claim
180 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of incident illumination; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being 1. movable along a first portion of a predetermined path to increase the effective size of said first aperture relative to said objective lens from a minimum to a maximum size and increase the effective size of said second aperture relative to said photosensitive means; and 2. movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; and c. means coupled to said diaphragm means and responsive to variations in said parameter to move said diaphragm means along said predetermined path.
Claim 2
Dependent Claim
180 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of incident illumination; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being 1. movable along a first portion of a predetermined path to increase the effective size of said first aperture relative to said objective lens from a minimum to a maximum size and increase the effective size of said second aperture relative to said photosensitive means; and 2. movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; and c. means coupled to said diaphragm means and responsive to variations in said parameter to move said diaphragm means along said predetermined path.
Claim 3
Dependent Claim
141 words
movable along a second portion of said path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; c. first and second windings magnetically coupled to said diaphragm means, said first and second windings being oppositely poled and effective to exert an unbalanced force on said diaphragm means to move said diaphragm means in response to changes in current flow through said first and second windings; d. a differential amplifier electrically coupled to said first and second windings and said photosensitive means and adapted to be responsive to variations in said parameter from the predetermined value to vary current through said first and second windings to adjust the effective size of said second aperture to effect a change in said parameter to the predetermined value.
Claim 4
Dependent Claim
141 words
movable along a second portion of said path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; c. first and second windings magnetically coupled to said diaphragm means, said first and second windings being oppositely poled and effective to exert an unbalanced force on said diaphragm means to move said diaphragm means in response to changes in current flow through said first and second windings; d. a differential amplifier electrically coupled to said first and second windings and said photosensitive means and adapted to be responsive to variations in said parameter from the predetermined value to vary current through said first and second windings to adjust the effective size of said second aperture to effect a change in said parameter to the predetermined value.
Claim 5
Dependent Claim
59 words
movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; and c. means coupled to said diaphragm means and responsive to variations in said parameter to move said diaphragm means along said predetermined path.
Claim 6
Dependent Claim
59 words
movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; and c. means coupled to said diaphragm means and responsive to variations in said parameter to move said diaphragm means along said predetermined path.
Claim 7
Dependent Claim
90 words
In a camera having an objEctive lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 8
Dependent Claim
90 words
In a camera having an objEctive lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 9
Dependent Claim
90 words
movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; and c. positioning means coupling said diaphragm means to said photosensitive means and responsive to variations in said parameter from the predetermined value to move said diaphragm means to a position along said predetermined path to adjust the effective size of said second aperture to effect a change in said parameter to said predetermined value.
Claim 10
Dependent Claim
90 words
movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means; and c. positioning means coupling said diaphragm means to said photosensitive means and responsive to variations in said parameter from the predetermined value to move said diaphragm means to a position along said predetermined path to adjust the effective size of said second aperture to effect a change in said parameter to said predetermined value.
Claim 11
Dependent Claim
141 words
movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means until a maximum effective size of said second aperture is reached; c. positioning means coupling said diaphragm means to said photosensitive means and responsive to variations in said parameter from the predetermined value to move said diaphragm means to a position along said predetermined path to adjust the effective size of said first aperture to effect a change in said parameter to said predetermined value; and d. indicating means coupled to said photosensitive means and after said second aperture has reached said maximum effective size adapted to be responsive to a selected value of said parameter to indicate that scene brightness is unsuitable for film exposure.
Claim 12
Dependent Claim
141 words
movable along a second portion of said predetermined path to maintain said first aperture at said maximum effective size and to further increase the effective size of said second aperture relative to said photosensitive means until a maximum effective size of said second aperture is reached; c. positioning means coupling said diaphragm means to said photosensitive means and responsive to variations in said parameter from the predetermined value to move said diaphragm means to a position along said predetermined path to adjust the effective size of said first aperture to effect a change in said parameter to said predetermined value; and d. indicating means coupled to said photosensitive means and after said second aperture has reached said maximum effective size adapted to be responsive to a selected value of said parameter to indicate that scene brightness is unsuitable for film exposure.
Claim 13
Dependent Claim
215 words
movable along a second portion of said predetermined path to maintain said first aperture at said minimum effective size and to further increase the effective size of said second aperture relative to said photosensitive means until a maximum effective size of said second aperture is reached; c. first and second windings magnetically coupled to said diaphragm means, said first and second windings being oppositely poled and effective to exert an unbalanced force on said diaphragm means to move said diaphragm means in response to changes in current flow through said first and second windings; d. circuitry coupled to said photosensitive means and said first and second windings and adapted to be responsive to variations in parameter from the predetermined value to vary current through said first and second windings to adjust the effective size of said second aperture to effect a change in said parameter to the predetermined value and including means coupled to said photosensitive means and adapted to produce a signal after said second aperture has reached said maximum effective size in response to a selected value of said parameter corresponding to an unsuitable film exposure condition; and e. indicating means coupled to said signal producing means and responsive to said signal for indicating that said scene illumination iS unsuitable for film exposure.
Claim 14
Dependent Claim
215 words
movable along a second portion of said predetermined path to maintain said first aperture at said minimum effective size and to further increase the effective size of said second aperture relative to said photosensitive means until a maximum effective size of said second aperture is reached; c. first and second windings magnetically coupled to said diaphragm means, said first and second windings being oppositely poled and effective to exert an unbalanced force on said diaphragm means to move said diaphragm means in response to changes in current flow through said first and second windings; d. circuitry coupled to said photosensitive means and said first and second windings and adapted to be responsive to variations in parameter from the predetermined value to vary current through said first and second windings to adjust the effective size of said second aperture to effect a change in said parameter to the predetermined value and including means coupled to said photosensitive means and adapted to produce a signal after said second aperture has reached said maximum effective size in response to a selected value of said parameter corresponding to an unsuitable film exposure condition; and e. indicating means coupled to said signal producing means and responsive to said signal for indicating that said scene illumination iS unsuitable for film exposure.
Claim 15
Dependent Claim
27 words
The invention as set forth in claim 2 wherein said diaphragm means includes a plate and each said aperture is at least partially formed in said plate.
Claim 16
Dependent Claim
29 words
The invention as set forth in claim 2 wherein said second aperture is contoured to permit said positioning means to maintain a constant illumination level on said photosensitive means.
Claim 17
Dependent Claim
41 words
The invention as set forth in claim 4 wherein said second aperture has a substantially triangular configuration and said first aperture has a first portion having a substantially triangular configuration and a second portion contoured to provide said maximum effective size.
Claim 18
Dependent Claim
90 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 19
Dependent Claim
90 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 20
Dependent Claim
90 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive meaNs having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 21
Dependent Claim
90 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive meaNs having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 22
Dependent Claim
28 words
The invention as set forth in claim 7 wherein said indicating means includes a lamp and means for energizing said lamp in response to said selected parameter value.
Claim 23
Dependent Claim
90 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 24
Dependent Claim
90 words
In a camera having an objective lens which is adapted to focus an image of an object in a film plane, an exposure control apparatus comprising: a. photosensitive means having an electrical parameter which varies as a function of the level of incident illumination, a predetermined value of said parameter corresponding to a desired film exposure condition; b. diaphragm means defining a first aperture disposed in a cooperative relation with the objective lens and a second aperture disposed in a cooperative relation with said photosensitive means, said diaphragm means being:
Claim 25
Dependent Claim
27 words
The invention as set forth in claim 9 wherein said diaphragm means includes a plate and each said aperture is at least partially formed in said plate.
Claim 26
Dependent Claim
29 words
The invention as set forth in claim 9 wherein said second aperture is contoured to permit said positioning means to maintain a constant illumination level on said photosensitive means.
Claim 27
Dependent Claim
41 words
The invention as set forth in claim 11 wherein said second aperture has a substantially triangular configuration and said first aperture has a first portion having a substantially triangular configuration and a second portion contoured to provide said maximum effective size.
Claim 28
Dependent Claim
28 words
The invention as set forth in claim 12 wherein said indicating means includes a lamp and means for energizing said lamp in response to said selected parameter value.
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) | 1975-04-25 | 1975-10-25 | 1976-04-25 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-25 | 1979-10-25 | 1980-04-25 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-25 | 1983-10-25 | 1984-04-25 | $7700.00 | Window Closed / Lapsed |