LIGHTING DEVICE, OPTICAL INSPECTION DEVICE, AND OPTICAL MICROSCOPE

摘要

PROBLEM TO BE SOLVED: To provide a lighting device capable of changing the beam angle distribution of illumination light while restraining loss in the quantity of light.SOLUTION: A lighting device comprises: a light source that emits light; a multiple reflection element 4 that passes light Lc through a light incident surface 4a, reflects the light therein multiples times, and then emits light from a light emission surface; and an optical element 3 that is placed on a light path between the light source and the multiple reflection element 4, and changes the beam angle distribution of light Lb. The optical element 3 at least includes a pair of two conical lenses 21 and 22, and during the passage of the light Lb through between the two conical lenses 21 and 22, the light path of a beam is switched at positions between the inner peripheral side and outer peripheral side of the pupil surface of the light Lb.SELECTED DRAWING: Figure 2