| 摘要 |
PURPOSE:To make it possible to measure the outward position and the inward position of a surface highly accurately without the effect of the state of the reflecting surface of a polariscope by focusing an image which is conjugate with the focal point on a mirror on a reflected- light-position detector. CONSTITUTION:When the light from a light source 5 enters, a trigger detector 8 transmits a trigger signal. The light emitted from a light source 1 is reflected from the mirror surface of a polariscope 9. The reflected light is condensed on a beam-position detector 4 through an optical system 3. At the time of the trigger generation, the direction of the mirror surface is constant. Therefore, the fluctuation of the output from the detector 4 is caused by the outward and inward movements of the surface. Thus the outward and inward positions of the surface are measured. Namely, a focal point F1 of the incident light L1 is focused on the detector 4 through the optical system 3. When the surface is moved outward or inward, the reflected light is moved to a light path L3. The focal point on the detector which is conjugate with the apparent movement of the focal point is moved to F2. Therefore, the incident point becomes S1. The amount of the outward or inward movement (d) is obtained based on the distance X1 between F1 and S1. Even if an angular error occurs in the reflected light under the state of the mirror surface, the deviation of the optical incident point on the detector 4 is very small, and the highly accurate measurement can be performed. |
