Position detecting method and apparatus
US5189494A · kind A · utility
81Cited by
4References
51Claims
0Family size
Inventor
Key dates
| Filing date | Jan 8, 1992 |
| Grant date | Feb 23, 1993 |
| Priority date | — |
| Expiry date | Jan 8, 2012 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG03F9/7076
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
A position detecting method and apparatus for detecting the relative position of a particular grating pattern with respect to a predetermined reference grating pattern, includes a signal forming step for forming first and second signals corresponding to moire fringes provided or to be provided by the patterns, the first and second signals having phases shiftable in opposite directions in accordance with the position of the particular grating pattern; and a position detecting step for detecting the position of the particular grating pattern on the basis of any difference in phase between the first and second signals.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.