Automatic focusing device of camera

Abstract

Abstract PURPOSE:To determine a desired composition, and also to take a photograph which is focused exactly by measuring a distance from an image pickup surface to an object to be photographed which is positioned at the shortest distance, and determining the extension amount of a photographic lens. CONSTITUTION:When a range finding part 1 is directed toward the vicinity of an object to be photographed and a shutter button is pushed at the time of photographing, a light is emitted from a light emitting part 2, and at the same time, the range finding part 1 starts to rotate. A light reflected by the object to be photographed, by a light of the light emitting part 2 is photodetected on a photodetector train 5. Outputs of photodetectors 5a-5d are compared with the voltage of a reference power source 8 in voltage comparators 7a-7d through a photoelectric converting circuit 6, and if each output level exceeds a voltage level of the power source 8, the output of each comparator 7a-7d becomes a high level. As a result, a high level signal is obtained from an output terminal 18 of a register 9, supplied to the register 9, and a photographic lens is extended by a distance signal corresponding to only an object to be photographed of the shortest distance. In this way, focusing can be executed exactly by a desired composition.

Inventors

• 👤 Saburo Sugawara
• 👤 三郎 菅原

Bibliographic Details