US 11,835,370 B2
Method for calculating position or angle of inspection target, storage medium, apparatus, and system
Satoshi Kubo, Tochigi (JP); and Takumi Kawamata, Tochigi (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Jan. 14, 2022, as Appl. No. 17/576,686.
Claims priority of application No. 2021-007471 (JP), filed on Jan. 20, 2021.
Prior Publication US 2022/0228889 A1, Jul. 21, 2022
Int. Cl. G01D 5/245 (2006.01); G01D 5/14 (2006.01)
CPC G01D 5/2454 (2013.01) [G01D 5/147 (2013.01)] 20 Claims
OG exemplary drawing
 
1. A method for measuring a position or an angle of an inspection target based on a sine wave signal and a cosine wave signal output from an encoder or a laser interferometer, the method comprising:
acquiring a temporary movement speed of the inspection target;
calculating an amplitude correction value corresponding to the temporary movement speed using information representing a relationship between a movement speed of the inspection target and amplitudes of the sine wave signal and the cosine wave signal, the information being stored in a memory;
correcting the amplitudes of the sine wave signal and the cosine wave signal using the amplitude correction value corresponding to the temporary movement speed in the information;
calculating an offset error in a Lissajous waveform using the sine wave signal and the cosine wave signal the amplitudes of which are corrected with the amplitude correction value, the offset error indicting an offset of the Lissajous waveform from an origin when the Lissajous waveform is drawn with the sine wave signal and the cosine wave signal on Cartesian coordinates; and
measuring the position or the angle of the inspection target using the offset error.