| 摘要 |
An image of a measurement light source, pref. a solid state laser, is formed on a workpiece surface by a lens axis of which is inclined wrt. The source's axis. A deflecting mirror opaque to the measurement light is placed at the intercept of these axes. A mirror semi-transparent tot he measurement light is placed pref. between the source and the deflecting mirror. A transducer system produces a signal dependent on the point of incidence of light returning from the workpiece surface. The lens axial position is controlled by this signal and results in a corresp. measurement signal. The deflecting mirror (38) is transparent for light of wavelengths outside the measurement light spectrum and is of optical quality on its rear side. An observation lens (70,72) is mounted behind it. |
