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US4552446A Expired / Lapsed US ⏱️ 0.0 years remaining

Light measurement compensation device for camera

Assignee: Canon Inc
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Filing: 1985-01-02
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Granted: 1985-11-12
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Expires: 2005-01-02
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Abstract

Abstract The disclosed light measurement compensation device for a camera includes the known resistors for aperture correction and for curvature correction in order to compensate for the error of light measurement in the full open aperture light measuring mode. The device also includes a resistor for compensating for the light measuring output difference present between two light measuring modes, or partial light measuring mode and average light measuring mode, and another resistor for shifting the light measuring output by a prescribed quantity. For this reason, even though the various light measuring modes, namely, full open aperture-average light measuring, stop down-partial light measuring, full open aperture-partial light measuring, and stop down-average light measuring modes, are selectively used, either an erroneous display or a drop of the exposure accuracy seldom takes place.

Inventors

  • 👤 Yasuo Suda
  • 👤 Kiyoshi Alyfuku
  • 👤 Akio Sunouchi
  • 👤 Nobuyuki Suzuki

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 15:06
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/08; G03B7/091; G03B7/095

Claims Analysis

Total Claims: 3
Claim 1
Independent Claim 88 words
A light measuring device for a camera capable of selecting a full open aperture light measuring mode, a stop-down light measuring mode, an average light measuring mode and a spot light measuring mode, comprising: (a) light measuring means for producing a corresponding electrical signal to the intensity of an incident light from an object to be photographed; and (b) means for shifting an output of said light measuring means by a prescribed quantity when said stop down light measuring mode and the spot light measuring mode are selected.
Claim 2
Dependent Claim 88 words
A light measuring device for a camera capable of selecting a full open aperture light measuring mode, a stop-down light measuring mode, an average light measuring mode and a spot light measuring mode, comprising: (a) light measuring means for producing a corresponding electrical signal to the intensity of an incident light from an object to be photographed; and (b) means for shifting an output of said light measuring means by a prescribed quantity when said stop down light measuring mode and the spot light measuring mode are selected.
Claim 3
Dependent Claim 20 words
A light measuring device according to claim 1, wherein said shifting means includes a resistor having a predetermined resistance value.

References Cited (Backward Citations)

US3896462A Cited
US3884584A Cited
US3990085A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1988-11-11 1989-05-13 1989-11-12 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1992-11-11 1993-05-13 1993-11-12 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1996-11-11 1997-05-13 1997-11-12 $7700.00 Window Closed / Lapsed

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