Asahi Kogaku Kogyo Kabushiki Kaisha

Hirokazu Ando

Masahiro Kawasaki

Chiharu Mori

An electric shutter circuit employs a photodiode which forms the collector load of a logarithmic amplifier. The photodiode is shunted with an active device which is caused to conduct during shutter operation to supply an additional current to the logarithmic amplifier to permit a rapid shutter response by assuring the rapid discharge of a memory storage capacitor.

Bypass circuits for improving the response of electric shutters

A memory capacitor in an electric shutter circuit has one terminal coupled to a voltage responsive element such as a diode, which operates to effectively reduce the level to which the capacitor is charged to thereby attain a decrease in discharge time of the capacitor enabling rapid shutter operation.

Timing circuits for camera shutters

An electrical system to be used in a camera for controlling exposure time. The electrical system includes a pair of substantially identical constant voltage sources respectively having inputs connected together. A buffer circuit is coupled between an interconnection of these inputs and the collector of a compression transistor to which a photosensitive means is connected and whose base is coupled to one of the constant voltage sources. A timing circuit is coupled to an expansion transistor, whose base is coupled to the other of the constant voltage sources.

Growing community of inventors

Tokyo, Japan

Hirokazu Ando