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:
Feb. 27, 2018
Filed:
Jun. 05, 2014
Tsinghua University, Beijing, CN;
Yu Zhu, Beijing, CN;
Leijie Wang, Beijing, CN;
Ming Zhang, Beijing, CN;
Zhao Liu, Beijing, CN;
Rong Cheng, Beijing, CN;
Kaiming Yang, Beijing, CN;
Dengfeng Xu, Beijing, CN;
Weinan Ye, Beijing, CN;
Li Zhang, Beijing, CN;
Yanpo Zhao, Beijing, CN;
Huichao Qin, Beijing, CN;
Li Tian, Beijing, CN;
Jin Zhang, Beijing, CN;
Wensheng Yin, Beijing, CN;
Haihua Mu, Beijing, CN;
Jinchun Hu, Beijing, CN;
TSINGHUA UNIVERSITY, Beijing, CN;
Abstract
A three-DOF (Degree of Freedom) heterodyne grating interferometer displacement measurement system comprises a dual-frequency laser, a grating interferometer, a measurement grating, receivers and an electronic signal processing component; the grating interferometer comprises a polarizing beam splitter, a reference grating and dioptric elements; the measurement system realizes displacement measurement on the basis of grating diffraction, the optical Doppler Effect and the optical beat frequency principle. Three linear displacements can be output by the system when the grating interferometer and the measurement grating perform a three-DOF linear relative motion. The measurement system can reach sub-nanometer and higher resolution and precision, and can simultaneously measure three linear displacements. The measurement system has the advantages of being environmentally insensitive, high in measurement precision, small in size, light in weight, and is capable of improving the overall performances of an ultra-precision stage of a lithography machine as a position measurement system for this stage.