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. 05, 2017
Filed:
Dec. 06, 2013
Shanghai Micro Electronics Equipment Co., Ltd., Shanghai, CN;
Tsinghua University, Beijing, CN;
Yu Zhu, Beijing, CN;
Ming Zhang, Beijing, CN;
Zhao Liu, Beijing, CN;
Rong Cheng, Beijing, CN;
Jing Wang, Beijing, CN;
Li Tian, Beijing, CN;
Dengfeng Xu, Beijing, CN;
Kaiming Yang, Beijing, CN;
Jinchun Hu, Beijing, CN;
Wensheng Yin, Beijing, CN;
Haihua Mu, Beijing, CN;
Hao Liu, Beijing, CN;
Chuxiong Hu, Beijing, CN;
SHANGHAI MICRO ELECTRONICS EQUIPMENT CO., LTD., Shanghai, CN;
TSINGHUA UNIVERSITY, Beijing, CN;
Abstract
A negative stiffness system for gravity compensation of a micropositioner of wafer table in lithography machine, characterized in that, the negative stiffness system includes at least three sets of quasi-zero stiffness units, each of the sets of quasi-zero stiffness units comprises a pair of negative stiffness springs and a positive stiffness spring, the positive stiffness spring is vertically positioned, the pair of negative stiffness springs are obliquely and symmetrically positioned at two sides of the positive stiffness spring, upper ends of the negative stiffness springs and the positive stiffness spring are connected together and fixed to the bottom surface of a rotor of the micropositioner, and lower ends of the negative stiffness springs and the positive stiffness spring are connected to a base, respectively. The system reduces the stiffness in vertical direction and prevents the influence of permanent magnet on its surroundings, while improving the bearing capacity.