US 12,117,526 B2
Displacement meter and article manufacturing method
Takayuki Uozumi, Tokyo (JP)
Assigned to CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed by CANON KABUSHIKI KAISHA, Tokyo (JP)
Filed on Jan. 8, 2021, as Appl. No. 17/144,511.
Claims priority of application No. 2020-011350 (JP), filed on Jan. 28, 2020.
Prior Publication US 2021/0231802 A1, Jul. 29, 2021
Int. Cl. G01S 17/08 (2006.01); G01B 11/02 (2006.01)
CPC G01S 17/08 (2013.01) [G01B 11/028 (2013.01)] 18 Claims
OG exemplary drawing
 
1. A displacement meter comprising:
a light source;
an illumination optical system configured to form a light intensity distribution at a predetermined position on an optical axis by using light from the light source such that a light intensity at a peripheral portion of the light intensity distribution is stronger than a light intensity at a center portion of the light intensity distribution;
a light deflection portion which has an opening on the optical axis and a reflection part configured to reflect light of the light intensity distribution formed by the illumination optical system at the predetermined position;
a first lens unit configured to collect light reflected by the reflection part and illuminate a measurement object;
a sensor array configured to detect light reflected by the measurement object and passing through the opening of the light deflection portion through the first lens unit; and
a measurement unit configured to detect a displacement of the measurement object by using outputs of the sensor array at different timings.