The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Sep. 15, 2020
Filed:
May. 24, 2019
Canon Kabushiki Kaisha, Tokyo, JP;
Toshiki Iwai, Utsunomiya, JP;
Takamitsu Komaki, Utsunomiya, JP;
Yasuyuki Unno, Utsunomiya, JP;
Nozomu Hayashi, Utsunomiya, JP;
CANON KABUSHIKI KAISHA, Tokyo, JP;
Abstract
A detection device includes an illumination optical system and a detection optical system. The illumination optical system is configured to illuminate a first diffraction grating having a first period in a first direction and a second diffraction grating having a second period different from the first period. The detection optical system is configured to detect light diffracted by the first and second diffraction gratings. The illumination optical system includes an optical member configured to form, on a pupil plane, a first pole and a second pole opposite to the first pole. The illumination optical system causes lights from the first and second poles to obliquely enter the first and second diffraction gratings from the first direction to illuminate the first and second diffraction gratings. The detection optical system detects diffracted light diffracted by one of the first and second diffraction gratings and by an other diffraction grating.