TWI843197B

An optical system for a shape measuring device of the present invention includes a parallel light irradiation system and an imaging optical system, in which the parallel light irradiation system includes a point light source, a collimator lens, and a telecentric lens having a both side or object side telecentric structure to be irradiated with light from the collimator lens through an object to be measured, the imaging optical system includes an image sensor onto which an image of a portion of the object to be measured, the image by light passing through the telecentric lens is projected, and the point light source includes an LED, a diffusion member that diffuses and emits light from the LED; and a pinhole member having a pinhole into which light from the diffusion member is incident.