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US 4,226,516 AGranted
Camera and viewfinder display device therefor
AssigneeCanon Kabushiki Kaisha
InventorTokuichi Tsunekawa
Life of this patent
Estimating the term…
Abstract
In the enclosed camera, the progress of a long time exposure is indicated by integrating a voltage over the exposure time and displaying the integrated voltage with an ammeter needle or a row of sequentially illuminated LEDs. According to an embodiment of the invention, the integrated voltage is derived from the integrator that controls the shutter exposure.
Claims10
A camera comprising:
- (a) a shutter time signal forming circuit, said circuit including a light sensing element so as to produce an output corresponding to the shutter time value based upon the brightness of an object;
- (b) a detecting circuit for detecting the output of the shutter time signal forming circuit and to produce a detect signal when the output of the shutter time signal forming circuit assumes a value corresponding to a predetermined minimum shutter time;
- (c) a shutter time control circuit for controlling the shutter time on the basis of the output of the shutter time signal forming circuit;
- and
- (d) exposure time progress display means for operating in response to the shutter time control circuit, and assuming an operative state in response to the detect signal from the detecting circuit.
2 more elements
A camera comprising:
- (a) a light measuring circuit for producing an output corresponding to the brightness of an object;
- (b) a timer circuit for controlling the exposure time on the basis of output from the light measuring circuit and for producing an output level varying with the progress of the exposure time;
- (c) a detecting circuit for detecting the output from the light measuring circuit and producing a signal when the value of the output from the light measuring circuit reaches a value corresponding to a given minimum exposure time;
- and
- (d) a display device for displaying the value corresponding to the output level of the timer circuit, and for becoming operative in response to the signal of the detecting circuit.
2 more elements
A camera comprising:
- (a) a light measuring circuit for producing an output corresponding to the brightness of an object;
- (b) an integrating circuit for integrating the output of the light measuring circuit;
- (c) exposure control means for producing an exposure stop signal when the output of the integrating circuit reaches a predetermined value;
- (d) shutter means for terminating the exposure in response to the exposure stop signal;
- (e) a detecting circuit for detecting the output from the light measuring circuit and producing a signal when the value of the output from the light measuring circuit reaches a value corresponding to a given minimum exposure time;
- (f) display means for displaying the output of the integrating circuit;
- and
- (g) a connecting circuit for connecting the integrating circuit to the display circuit in response to the signal from the detecting circuit.
5 more elements
A camera comprising:
- (a) a light measuring circuit for producing an output corresponding to the brightness of an object;
- (b) a timer circuit for controlling the exposure time on the basis of the output from the light measuring circuit;
- (c) indication means for displaying the exposure information on the basis of the output from the light measuring circuit;
- (d) a detecting circuit for detecting the output from the light measuring circuit and for producing a signal when the output value from the light measuring circuit assumes a given value corresponding to a given long exposure time;
- and
- (e) a selector circuit for applying the output of the timer circuit to the indication means in response to the signal from said detecting circuit, said indication means being arranged to display the progress of exposure time in response to the output of said timer circuit.
3 more elements
A camera comprising:
- (a) a shutter time signal forming circuit for forming a signal corresponding to a shutter time;
- (b) a detecting circuit for detecting shutter time through the shutter time signal formed by said shutter time signal forming circuit, said detecting circuit being arranged to produce a signal when the detected shutter time exceeds a predetermined length of time;
- (c) a shutter time control circuit for controlling the shutter time on the basis of said signal from said shutter time signal forming circuit;
- and
- (d) display means for displaying the progress of the shutter time controlled by said shutter time control circuit, said display means being arranged to operate in response to the signal produced by said detecting circuit.
2 more elements
A camera comprising:
- (a) a shutter time controlling circuit for controlling the shutter time;
- and
- (b) display means for displaying the progress of shutter time controlled by said shutter time controlling circuit, said display means being arranged to operate when said shutter time is longer than a predetermined length of time.
A camera comprising:
- (a) a timer circuit for controlling the shutter time;
- and
- (b) display means for displaying the progress of exposure time based on the output of said timer circuit, said display means being arranged to operate when said shutter time is longer than a predetermined length of time.
A display device for a camera comprising:
- (a) exposure time progress display means for displaying the progress of exposure time;
- and
- (b) means coupled to said display means, said display means being arranged to be rendered operative by said coupled means when said exposure time is longer than a predetermined length of time.
Dependencies are inferred from the claim text.