Displacement detecting apparatus
US5477333A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 6, 1994 |
| Grant date | Dec 19, 1995 |
| Priority date | — |
| Expiry date | Oct 6, 2014 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01B11/00
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A displacement detecting apparatus for detecting a displacement between an object lens thereof and a measured surface in a non-contact manner. The displacement detecting apparatus comprises an object lens for focusing laser beam on the measured surface. A detecting optical system is provided to detect a focus error signal which represents a difference between a distance of the object lens from the measured surface and a focal distance of the object lens, in accordance with a reflected light from the measured surface. An actuator is provided to move the object lens in an optical axis in a manner to cause the object lens distance to coincide with the focal distance, in accordance with an output signal from the detecting optical system. A moving body includes a linear scale or a scale head and movable with the object lens. The linear scale is disposed coaxially with the optical axis and connected to the actuator. A support member is provided to movably support the moving body. Additionally, a balance weight is connected to the moving body in a manner that the center of gravity of the moving body coincides with the center of driving force of said actuator and with the center of support…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.