Photoelectric encoder and electronic equipment using the same

Abstract

The present invention provides an optical encoder and an electronic apparatus having the same.The 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 DEG from the light reception signal A+, and a light reception signal B- shifted in phase by 180 DEG from the light reception signal B+, are inputted to the OR circuit 22 of the signal processing circuit. Thus, the signal processing circuit does not need NOT circuits for inverting the light reception signals 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.

Description

technical field [0001] The present invention relates to an optical encoder that uses a light receiving element to detect the position, speed, direction, etc. Optical encoder. Background technique [0002] In the past, in (Japanese) Patent Laying-Open No. 1-136019, an encoder is disclosed, which inputs a pulse signal with a phase difference of 90 degrees to an "exclusive OR" circuit, so that twice the resolution of the past can be obtained. Rate. [0003] In addition, in (Japanese) Unexamined Patent Publication No. 1-156621, an optical encoder is disclosed, which inputs four signals with a phase difference of 45° to an "OR" logic circuit, so that signals with a phase difference of 90° can be obtained. two signals. [0004] In addition, in (Japanese) Unexamined Patent Publication No. 3-37518, an encoder is disclosed, which inputs a signal obtained from the "exclusive OR" of signals with a phase difference of 90° as the clock of the shift register, and uses the One of the o...

AI Technical Summary

Problems solved by technology

[0008] However, in the case of taking the "exclusive OR" of such two pulse signals, a delay of one gate (gate) must be generated in the logic circuit.

[0009] In a normal logic circuit, this delay is within the error range, but in a light receiving circuit including a light receiving element for processing minute signals, there is the following problem: the delay of one gate causes a delay to the signal at There is a difference in the impedance between the input and output, the duty cycle of the output signal deviates, and the cycle fluctuation becomes larger, so the advantage of twice the resolution cannot be obtained.

[0010] In addition, in (Japanese) Unexamined Patent Publication No. 3-37518, since the signal obtained from the "exclusive OR" signal is logically combined with the original signal before the logic operation, it is accompanied by a gate delay, which is prone to malfunction.

[0011] In addition, in (Japanese) Utility Laid-Open No. 7-12924 and (Japanese) Patent Laid-Open No. 2007-40959, signal pulses are generated using inverted signals obtained from light-receiving elements, but there are The two pulses are 90° out of phase, resulting in the aforementioned gate delay

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