| 摘要 |
PURPOSE:To measure accurately a minute shape by providing an in-focus state discriminating optical system and an inclination angle measuring optical system which share a part of an optical path and moving a part of the former while holding the optical path near an object lens and providing a movement extent measuring means of this moving. CONSTITUTION:The light from a light source 8 of an in-focus state discriminating optical system 2 passes a collimator lens 10, etc. and is projected from an object lens 20 to an object 50 to be measured, and the reflected wave is led to a sensor 26 whose output is zero in the in-focus state, and an actuator 40 is servo- driven to perform auto-focusing. The extent of movement of a casing 6 is measured by a length measuring means 42 to measure the position of the surface of the object 50 to be measured. This position measurement is performed for the whole of the surface of the object 50 to be measured. The position of the centroid of the luminous flux is detected in the in-focus state by an inclination angle measuring optical system provided with a light source 28 different in wavelength from the light source 8, a sensor 38, etc. to measure the angle of inclination. |
