US 11,953,371 B2
Optical sensor synchronizing to ambient light flicker and operating method thereof
Zi-Hao Tan, Penang (MY); and Joon-Chok Lee, Penang (MY)
Assigned to PIXART IMAGING INC., Hsin-Chu County (TW)
Filed by PixArt Imaging Inc., Hsin-Chu County (TW)
Filed on Jul. 13, 2022, as Appl. No. 17/863,663.
Application 17/863,663 is a continuation of application No. 17/124,332, filed on Dec. 16, 2020, granted, now 11,422,025.
Prior Publication US 2022/0349747 A1, Nov. 3, 2022
This patent is subject to a terminal disclaimer.
Int. Cl. G01J 1/42 (2006.01); G01J 1/44 (2006.01)
CPC G01J 1/4204 (2013.01) [G01J 1/44 (2013.01); G01J 2001/446 (2013.01)] 20 Claims
OG exemplary drawing
 
1. An operating method of an optical sensor, comprising:
counting a square wave signal, which is generated from an ambient light flicker, using a clock signal;
synchronizing image frames to a flicker frequency of the ambient light flicker to eliminate an incorrect motion identification when the ambient light flicker is well detected; and
not synchronizing the image frames to the flicker frequency when the ambient light flicker is not well detected,
wherein whether the ambient light flicker is well detected or not is identified according to a counting value of every square wave signal within a count period as well as consistency of multiple counting values of all square wave signals within the count period.