TWO-STAGE LIGHT BEAM SWITCH

Japanese Patent JP3477653

B2

PURPOSE: To attain simplification of setting work and also miniaturization of a device through the use of only two lines of wiring to connect a control part and a light projecting part and the control part and a light receiving part.
CONSTITUTION: Two light emitting diodes are used as the light projecting part 2 by connecting them in anti-parallel, and two photodiodes are used as the light receiving part 3 by connecting them in anti-parallel. Both the ends of two light emitting diodes are connected to a light projection circuit 11 to generate a constant current pulse signal whose polarity changes alternately, and a light reception circuit 12 is provided with a built-in window comparator in order to discriminate a signal outputted from both ends of two ohotodiodes. Thus, the wiring between the control part 1 and the light projecting part 2 and the wiring between the control part 1 and the light receiving part 3 can be managed with two lines of the wiring, and construction is improved. Besides, the light emitting diode and the photodiode of anti-parallel connection are adopted for the light projecting part 2 and the light receiving part 3 respectively, and an H bridge and the window comparator matching with these are used for the light projection circuit 11 and the light reception circuit 12 so that configuration can be simplified.

Ken Narita

JP12055995A

December 10, 2003

April 20, 1995

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Takenaka Engineering Co., Ltd.

G01V8/20; H01H35/00; H03K17/78; (IPC1-7): H03K17/78; G01V8/20; H01H35/00

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