Patent ID: 9534936
Date: 2017-01-03
CPC Classifications: G01D

Claim:
1. A reference signal generation apparatus comprising: a reference point detection light-receiver that receives light from a reference point detection pattern, the light being emitted from a light source; and a reference signal generation circuit that generates a reference signal from a reading result of the reference point detection pattern read by the reference point detection light-receiver, wherein the reference point detection light-receiver comprises: a unit light-receiving region including a first light-receiving element array and a second light-receiving element array, the first light-receiving element array comprises: the second light-receiving element array comprises: the second light-receiving element array is disposed in a second direction for the first light-receiving element array and disposed with an offset in the first direction for the first light-receiving element array, the second direction being orthogonal to the first direction, the reference signal generation circuit outputs the reference signal that starts at a period where levels of the first signal and the second signal become equal and ends at a period where levels of the third signal and the fourth signal become equal, wherein the reference point detection light-receiver includes a plurality of the unit light-receiving regions that are aligned in the second direction, wherein the reference signal generation circuit outputs the reference signal that starts at a period when a value obtained by subtracting the second signal from the first signal becomes a predetermined value and ends at a period when a value obtained by subtracting the fourth signal from the third signal becomes the predetermined value, wherein the reference signal generation circuit wherein the reference signal generation circuit comprises: wherein the logical AND between the first comparison signal and the second comparison signal is output as the reference signal.