US 11,914,798 B2
Count per inch calibration method and optical navigation device
Jr-Yi Li, Hsin-Chu (TW)
Assigned to PixArt Imaging Inc., Hsin-Chu (TW)
Filed by PixArt Imaging Inc., Hsin-Chu (TW)
Filed on Feb. 14, 2023, as Appl. No. 18/109,835.
Application 18/109,835 is a continuation of application No. 17/385,943, filed on Jul. 27, 2021, granted, now 11,609,646.
Claims priority of provisional application 63/160,937, filed on Mar. 15, 2021.
Prior Publication US 2023/0185388 A1, Jun. 15, 2023
This patent is subject to a terminal disclaimer.
Int. Cl. G06F 3/0354 (2013.01); G06F 3/03 (2006.01); G06F 3/038 (2013.01)
CPC G06F 3/03543 (2013.01) [G06F 3/0317 (2013.01); G06F 3/0383 (2013.01)] 10 Claims
OG exemplary drawing
 
1. An optical navigation device, comprising:
an optical sensor, configured to sense optical data; and
a processing circuit, configured to compute motions of the optical navigation device based on the optical data, and configured to output the motions, wherein a first CPI is set to the processing circuit;
wherein the processing circuit receives a calibration command to calibrate the first CPI to a second CPI, wherein the second CPI is computed via following steps:
(a) computing a real CPI corresponding to times of motions output by the processing circuit during a time interval that a relative displacement between the optical navigation device and a surface reaches a first predetermined distance;
(b) computing a ratio between the real CPI and the first CPI or a difference between the real CPI and the first CPI; and
(c)generating the second CPI based on the ratio or the difference;
wherein the step (a) further comprises:
providing a calibration ruler pattern, wherein the calibration ruler comprises a plurality of mark regions;
determining the relative displacement according to the mark regions.