| 摘要 |
<p>The probe comprises a light source (12) and a lens system (14, 16) for focussing a spot of light (18) on a workpiece surface (20). A detector system (26, 27, 28A, 28B) detects whether the spot is in focus, and a servo motor (29) drives the lens (16) axially in order to keep it in focus. The axial movement necessary for this is detected by a sensor (82) to provide a measurement of the axial position of the surface (20). In order to measure the slope of the surface (20), a refractive plate (30) can be tilted to deflect the light beam to focus on adjacent points (18', 18'').</p> |
