Radiant energy – Photocells; circuits and apparatus – Optical or pre-photocell system
Patent
1989-04-17
1990-11-20
Nelms, David C.
Radiant energy
Photocells; circuits and apparatus
Optical or pre-photocell system
25023114, 354435, 354230, G01D 534, H01J 4014, G03B 708
Patent
active
049720783
ABSTRACT:
In at least one of a plurality of shutter vanes forming a shutter there are provided a plurality of openings adapted to detect the movement of the shutter vanes. A photointerrupter is turned on and off by the openings when the shutter vanes move. An output voltage of the photointerrupter is compared with a reference voltage by a comparator. A series combination of a switch, which is turned on and off by the output voltage of the comparator, and a resistor is connected between the output of the photointerrupter and ground. The output signal of the comparator is delayed. The delayed version and the output signal of the comparator are exclusive ORed to produce a train of pulses corresponding to the openings as the shutter vanes move. A drive and control section is responsive to the count of the pulses to control the operation of the shutter.
REFERENCES:
patent: 4558226 (1985-12-01), Takada et al.
patent: 4591708 (1986-05-01), Shu
patent: 4708454 (1987-11-01), Kodaira et al.
patent: 4751543 (1988-06-01), Kodaira et al.
patent: 4762992 (1988-08-01), Gat et al.
patent: 4835564 (1989-05-01), Nakagawa et al.
Hasebe Shinichi
Sasaki Masayuki
Kabushiki Kaisha Toshiba
Messinger Michael
Nelms David C.
LandOfFree
Pulse generating circuit for detecting aperture size of camera s does not yet have a rating. At this time, there are no reviews or comments for this patent.
If you have personal experience with Pulse generating circuit for detecting aperture size of camera s, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Pulse generating circuit for detecting aperture size of camera s will most certainly appreciate the feedback.
Profile ID: LFUS-PAI-O-455428