US3563153A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Camera light measuring system
Assignee: Pentax Corp
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Filing: 1968-08-21
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Granted: 1971-02-16
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Expires: 1988-08-21
Abstract
Abstract A system for measuring the light through a camera lens under diaphragm-open and diaphragm-adjusted positions includes a photoresistor located behind the diaphragm and connected to a meter through a bridge network including in an arm thereof one of a pair of outputs of a variable resistor device. The variable resistor device includes a cylindrical resistance element angularly adjustable in accordance with shutter speed and film rating, a movable contact engaging the resistance element and movable in response to the preset value of the diaphragm and a stationary second contact engaging the resistance element at a point corresponding to diaphragm-open position. A switch is actuatable to alternatively connect the first and second contacts into the circuit with the full opening and adjusted closing of the diaphragm respectively.
Inventors
- 👤 Koichiro Watanabe
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 03:30
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/081; G03B7/085
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
161 words
A camera light-measuring system comprising an adjustable diaphragm; a photosensitive element exposed to light traversing said diaphragm, a current meter, a resistance network having a pair of first and second outputs alternatively connected in circuit with said photosensitive element and a pair of first and second resistance adjustments one of said outputs responding to said pair of adjustments and the other of said outputs responding to only one of said adjustments, and means for selectively connecting one of said outputs into said circuit, said resistance network comprising a variable resistor including a movable resistance element defining said first adjustment, an independently adjustable first contact element defining said second adjustment, and a stationary second contact element engaging said resistance element, said resistance element being movable relative to said stationary contact element, said first output being between said first contact element and a predetermined point on said resistance element and said second output being beTween said second contact element and said predetermined point.
Claim 2
Dependent Claim
161 words
A camera light-measuring system comprising an adjustable diaphragm; a photosensitive element exposed to light traversing said diaphragm, a current meter, a resistance network having a pair of first and second outputs alternatively connected in circuit with said photosensitive element and a pair of first and second resistance adjustments one of said outputs responding to said pair of adjustments and the other of said outputs responding to only one of said adjustments, and means for selectively connecting one of said outputs into said circuit, said resistance network comprising a variable resistor including a movable resistance element defining said first adjustment, an independently adjustable first contact element defining said second adjustment, and a stationary second contact element engaging said resistance element, said resistance element being movable relative to said stationary contact element, said first output being between said first contact element and a predetermined point on said resistance element and said second output being beTween said second contact element and said predetermined point.
Claim 3
Dependent Claim
25 words
The light-measuring system of claim 1 wherein said diaphragm includes presetting means and comprising means coupling said diaphragm presetting means to said first contact element.
Claim 4
Dependent Claim
101 words
The light-measuring system of claim 1 comprising an automatic preset diaphragm mechanism coupled to said diaphragm and including a first control element movable in response to said diaphragm preset value and coupled to and movable with said first contact element, and a second control element for alternatively moving said diaphragm to its fully open position and its preset position and actuable with said selective output-connecting means to connect said first output into said circuit with the fully open position of said diaphragm and to connect said second output into said circuit with the closing of said diaphragm to its preset position.
Claim 5
Dependent Claim
37 words
The light-measuring system of claim 3 wherein said stationary second contact element engages said resistance element at a position corresponding to that engaged by said movable first contact element when adjusted to said diaphragm fully open position.
Claim 6
Dependent Claim
28 words
The light-measuring system of claim 2 wherein said resistance element is of arcuate configuration and rotatable about its longitudinal axis coaxial with the longitudinal axis of said diaphragm.
Claim 7
Dependent Claim
44 words
The light-measuring system of claim 1 wherein said first contact element is adjustable to positions corresponding to diaphragm aperture positions and said second contact element engages said resistance element at a position corresponding to the diaphragm fully open position of said first contact element.
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) | 1974-02-15 | 1974-08-17 | 1975-02-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-02-15 | 1978-08-17 | 1979-02-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-02-15 | 1982-08-17 | 1983-02-16 | $7700.00 | Window Closed / Lapsed |