US 7,612,327 B2Granted

Optical encoder and electronic equipment having the same

AssigneeSharp Kabushiki Kaisha

InventorNorikazu Okada

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Abstract

An optical encoder of the invention has an OR circuit 21 to which light reception signals A+, B+ are inputted, an OR circuit 22 to which light reception signals A−, B− are inputted, and an AND circuit 23 to which an output signal C of the OR circuit 21 and an output signal D of the OR circuit 22 are inputted. In this optical encoder, a light reception signal A− shifted in phase by 180° from the light reception signal A+, and a light reception signal B− shifted in phase by 180° from the light reception signal B+, are inputted to the OR circuit 22 of the signal processing circuit 15. Thus, the signal processing circuit 15 does not need NOT circuits for inverting the light reception signal A+ and B+. This optical encoder can avoid occurrence of phase differences due to gate delay among signals and detect the mover with signals of excellent duty and periodic precisions.

Claims7

Dependent claims

An optical encoder comprising:

a light emitting section;
a light receiving section having a plurality of light receiving elements placed in array along one direction in a region that can be reached by light derived from the light emitting section, and a mover having light-on portions which make the light incident on the light receiving elements and light-off portions which inhibit the light from being incident on the light receiving elements, the light-on portions and the light-off portions alternately pass through specified positions corresponding to the light receiving elements when the mover moves along the one direction, wherein the optical encoder detects movement of the mover, the optical encoder further comprising:
a signal processing section to which a first light reception signal and second, third and fourth light reception signals shifted in phase by 90°, 180°, 270° respectively from the first light reception signal are inputted from the light receiving section, and which balances gate delays due to signal processing for each of the first to fourth light reception signals with one another.

Dependencies are inferred from the claim text.