Focusing point signal generator

Abstract

Abstract PURPOSE: To stably create the focusing point signal in the automatic fucusing device by performing the generation and OFF of the focusing point signal at the specified time. CONSTITUTION: Front and rear focuses are displayed in lamps 8, 10 through AND gates 5, 6 according to the front and rear focus decision signals from the comparison part of a module for automatic focus detection inputted from terminal 7. When the photographing lens is moved by turning its distance ring, the decision signal inputted to the terminal 7 inverts in the focusing position, causing an FF 4 to be set by way of an inverter 9, differentiation circuits 12, 11 and OR circuit 13 then the gates 6, 5 become forbidden state, to go off the lamps 8, 10. At the same time, the focusing display lamp 14 to which the set output of the FF 14 is applied as the focusing signal lights up. Thence, the FF4 is reset by way of the differentiation circuit 16 by the turning angle signal of the distance ring applied at the time when the photographing distance by the photographing lens moving together with the distance ring deviates from the preset allowable distance range. The focusing signal then goes ON, thus the focusing signal is stably created. COPYRIGHT: (C)1980,JPO&Japio

Inventors

• 👤 Akira Takahashi
• 👤 Susumu Iguchi

Bibliographic Details