| 摘要 |
PURPOSE:To measure the shape readily without contact by receiving parallel laser beams which are focussed sufficiently small on a profile of the concave surface by a plane mirror, and measuring the positions of the spots corresponding to two adjacent positions on the light receiving surface, which is arranged at a right angle with an x axis. CONSTITUTION:The parallel laser beam whose diameter is sufficiently small in comparison with the radius of curvature of the concave surface to be measured are received by the profile of the concave surface via the plane mirrors 3 and 2 along the x axis. The reflected beam from the concave surface is received by the receiving surface 4 which is crossed with the x axis at a right angle. The reflected beam spot on the receiving surface 4 is observed, and the position xM on the plane mirror 2 on the x axis, the position xS on the light receiving surface 4, and the position yP in the y direction of the spot on the light receiving surface 4 are measured. Then the light receiving surface 4 is displaced in the x axis direction by DELTAxS, and the displacement DELTAyP of the spot in the y direction at this time is measured. The shape of the concave surface is obtained from said measured values by using the known equation. |
