US4984006A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Brightness measuring apparatus for providing adequate object brightness and a flashlight emission apparatus providing adequate exposure, irrespective of photographing conditions
Assignee: Minolta Co Ltd
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Filing: 1990-04-18
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Granted: 1991-01-08
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Expires: 2010-04-18
Abstract
Abstract The brightness measuring apparatus according to this invention comprises a plurality of light receiving elements for respectively receive light from a plurality of areas in a photographic range and output values corresponding to the areas based on the amounts of light received, and judges whether or not the object is under rear light conditions based on the outputted values and the value of rear light detection level which is decided based on focal length of a photographing lens, image magnification, object distance, or brightness of background.
Inventors
- 👤 Masayuki Ikemura
- 👤 Takehiko Karasaki
- 👤 Manabu Inoue
- 👤 Takehiro Katoh
- 👤 Yasuteru Yamano
- 👤 Koji Hata
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-08 23:34
CPC Classifications
G; G03; G03B; G03B7/00; G03B7/28; G03B7/08; G03B7/099; G03B7/0993; G03B7/0997; G03B7/09979
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
258 words
An apparatus for flash photography, comprising: first measuring means for measuring a brightness of a main object located in approximate center of a scene; second measuring means for measuring a brightness of a background situated in a peripheral part of said scene; rear light judging means for judging whether or not said main object is under rear light condition on the basis of the outputs of said first and second measuring means; flashlight emission means for emitting a flashlight; selection means for selecting a forced emission mode in which a photographing operation is performed with the flashlight emission irrespective of the brightness of said main object and that of said background; exposure control value calculation means for calculating an exposure control value so that the peripheral part of said scene is overexposed by a first predetermined amount when said rear light judging means judges that said main object is under rear light condition, and for calculating an exposure control value so that the main object is underexposed by a second predetermined amount when said rear light judging means judges that said main object is not under rear light condition and said selection means selects said forced emission mode; exposure control means for controlling an exposure amount on the basis of the exposure control value calculated by said exposure control value calculation means; and emission control means for actuating said flashlight emission means when said rear light judging means judges that said main object is under rear light condition, or when said selection means selects the forced emission mode.
Claim 2
Independent Claim
258 words
An apparatus for flash photography, comprising: first measuring means for measuring a brightness of a main object located in approximate center of a scene; second measuring means for measuring a brightness of a background situated in a peripheral part of said scene; rear light judging means for judging whether or not said main object is under rear light condition on the basis of the outputs of said first and second measuring means; flashlight emission means for emitting a flashlight; selection means for selecting a forced emission mode in which a photographing operation is performed with the flashlight emission irrespective of the brightness of said main object and that of said background; exposure control value calculation means for calculating an exposure control value so that the peripheral part of said scene is overexposed by a first predetermined amount when said rear light judging means judges that said main object is under rear light condition, and for calculating an exposure control value so that the main object is underexposed by a second predetermined amount when said rear light judging means judges that said main object is not under rear light condition and said selection means selects said forced emission mode; exposure control means for controlling an exposure amount on the basis of the exposure control value calculated by said exposure control value calculation means; and emission control means for actuating said flashlight emission means when said rear light judging means judges that said main object is under rear light condition, or when said selection means selects the forced emission mode.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1994-01-07 | 1994-07-09 | 1995-01-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1998-01-07 | 1998-07-09 | 1999-01-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2002-01-07 | 2002-07-09 | 2003-01-08 | $7700.00 | Window Closed / Lapsed |