Negative stiffness system for gravity compensation of micropositioner
US9752643B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Dec 6, 2013 |
| Grant date | Sep 5, 2017 |
| Priority date | — |
| Expiry date | Jan 1, 2034 |
Classification
- Technology area (CPC F)Mechanical Engineering; Lighting; Heating
- CPC primaryF16F2228/063
- WIPO fieldOptics
- WIPO sectorInstruments
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.