Device for oblique light irradiation

Abstract

To freely adjust the angle of the light incident on a workpiece in a light irradiation part for oblique irradiation of the workpiece with light without needing to move a large light irradiation part, on the exit side of a collimation lens or a collimation mirror, in a light irradiation part, there is a flat mirror which is moved in the direction in which the length of the optical path of the irradiation light is changed, such that its angle is changed with respect to the optical axis, and at the same time, the center of an area to be irradiated by reflection of the flat mirror essentially does not move. Thus, the angle of the light incident in the workpiece can be changed. Furthermore, by changing the angle of the collimation mirror with reference to the optical axis and by moving the collimation mirror in the direction in which the length of the optical path of the irradiation light is changed, the angle of the light incident in the workpiece can be changed without using a flat mirror.

Dependencies are inferred from the claim text.