Apparatus for detecting focusing state of objective lens
US4792668A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 2, 1986 |
| Grant date | Dec 20, 1988 |
| Priority date | — |
| Expiry date | Dec 2, 2006 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG02B7/36
- WIPO fieldOptics
- WIPO sectorInstruments
Abstract
An apparatus for detecting a focusing state of an objective lens comprises optical means for forming light intensity distributions of object images whose relative positional relationship changes with the focusing state of the objective lens, sensing means having a plurality of sensors for sensing the light intensity distributions to produce first and second signals relating to the light intensity distributions, signal processing means for relatively displacing the first and second signals by determining correlation information and producing a signal for adjusting the focusing state of the objective lens in accordance with the correlation information, and altering means for altering a displacement range within which the first and second signals are relatively displaced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.