Exposure value display system for a camera

• US 3,971,048 A
• Filed: 09/30/1974
• Issued: 07/20/1976
• Est. Priority Date: 10/02/1973
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Ito, Tadashi, Okuno, Youichi, Nakamoto, Soichi
• Primary Examiner(s): Peters, Jr., Joseph F.
• Application Number:
  US05/510,711
• Time in Patent Office: 659 Days
• Field of Search: 354/23 R, 354/23 D, 354/50, 354/51, 354/60, 354/60 E, 354/60 L, 354/53, 354/54, 354/56, 356/218, 356/226, 356/227
• US Class Current: 396/292
• CPC Class Codes: G03B 17/20 visible in viewfinder

Abstract

In a single lens reflex camera equipped with a shutter time preselection-automatic exposure range and a diaphragm aperture preselection-automatic exposure range, the drive circuits of a light-sensor and a digit readout assembly arranged in the view finder are controlled in time-spaced relation to each other by timing signals. These signals in turn are controlled by a train of clock pulses to alternately bring the sensor and the digit readout assembly into sequential operation. In this manner, the light value as sensed by the sensor is not affected by any part of the light from the energized digit readout assembly.

Claims

1. An exposure value display system for a camera of TTL type comprising in combination:

a. a finder optical system, said finder optical system being associated with an objective lens;

b. sensor means arranged in said finder optical system to receive light passing through said objective lens;

c. first control means for controlling the light-metering operation of said sensor means;

d. display means arranged in said finder optical system to display an exposure value;

e. second control means for controlling the display operation of said display means; and

f. pulse generator means connected to said first and second control means for supplying output pulses which control the operation periods of said first and second control means in time-displaced relation with respect to each other in sequence.

2. An exposure value display system according to claim 1, wherein said sensor means includes a photodiode.

3. An exposure value display system according to claim 1, wherein said display means includes light-emitting diodes.

4. An exposure value display system according to claim 1, wherein said sensor means is connected to an exposure control means, said exposure control means deriving said exposure value in correspondence with the light value sensed by said sensor means.

5. An exposure value display system according to claim 1, wherein said pulse generator means includes a timing pulse generator.