US 11,874,147 B2
Optical encoder with alignment photodiodes
Chung-Min Thor, Penang (MY); and Meng-Yee Lim, Penang (MY)
Filed by PIXART IMAGING INC., Hsin-Chu County (TW)
Filed on Dec. 19, 2022, as Appl. No. 18/083,621.
Application 18/083,621 is a continuation of application No. 16/878,054, filed on May 19, 2020, granted, now 11,566,922.
Prior Publication US 2023/0122480 A1, Apr. 20, 2023
Int. Cl. G01D 5/36 (2006.01); G01D 5/347 (2006.01); G01D 5/245 (2006.01); G01D 18/00 (2006.01)
CPC G01D 5/366 (2013.01) [G01D 5/2457 (2013.01); G01D 5/3473 (2013.01); G01D 18/00 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An optical encoder, comprising:
an optical sensor, configured to receive modulated light from an encoding medium, and comprising:
a detection photodiode array, arranged opposite to the encoding medium, and photodiodes of the detection photodiode array are periodically arranged along a direction by a distance; and
a first photodiode and a second photodiode, respectively arranged at two sides of the detection photodiode array in the direction, each of the first photodiode and the second photodiode having a trapezoid sensing surface, and separated from the detection photodiode array by three times of the distance in the direction.