OPTICAL SYSTEM FOR SHAPE MEASUREMENT DEVICE

To provide an optical system for a shape measurement device that can reduce luminance variations.SOLUTION: An optical system A for a shape measurement device of the present invention includes: a parallel light irradiation unit 1 for irradiating a measurement target part, which is an outside circumferential part of a disc-like measurement target object Ob, with parallel light so that the parallel light is applied along the round surface of the target measurement object Ob and the measurement target part is arranged in the light flux; and an imaging optical system 2 including an image sensor on which a shadow image of the measurement target part is projected, the imaging optical system taking the shadow image of the measurement target part. The parallel light irradiation unit 1 includes: a point light source 11a; a collimator lens 12 for emitting light from the point light source 11a in parallel; and a telecentric lens 13 on which light from the collimator lens 12 is applied through the measurement target object. The point light source 11a includes: an LED111; an optical fiber 112a as an example of a light diffusion member for diffusing light from the LED111 and emitting the light; and a pin-hole member 113 forming a pin-hole on which light from the optical fiber 112a is incident.SELECTED DRAWING: Figure 1 【課題】本発明は、輝度ムラを低減できる形状計測装置用光学系を提供する。【解決手段】本発明の形状計測装置用光学系Ａは、円盤状の被測定物体Ｏｂの外周端縁部分である被測定部に対し、被測定物体Ｏｂの円形面に沿うように、かつ、前記被測定部が光束の中に配されるように平行光を照射する平行光照射系１と、前記被測定部の影像が投影されるイメージセンサを含み、前記被測定部の影像を撮像する撮像光学系２とを備え、平行光照射系１は、点光源１１ａと、点光源１１ａからの光を平行光にして射出するコリメータレンズ１２と、コリメータレンズ１２からの光が被測定物体越しに照射されるテレセントリックレンズ１３とを備え、点光源１１ａは、ＬＥＤ１１１と、ＬＥＤ１１１からの光を拡散して射出する拡散部材の一例としての光ファイバー１１２ａと、光ファイバー１１２ａからの光が入射されるピンホールを形成したピンホール部材１１３とを備える。【選択図】図１