Patent ID: 7957636

Claim:
An illumination apparatus which illuminates a surface of an object having a three-dimensional shape, the illumination apparatus comprising: a light source; a guide configured to guide light from the light source to a surface of the object; and a diffuser which has a diffusion-reflection surface that faces a light exit surface of the guide via the object; wherein the diffuser is arranged at such a position that the light which is emitted from the guide and is not directly incident on the object is incident on the diffusion-reflection surface while a part of the light reflected and diffused by the diffusion-reflection surface is incident on a surface of the object, and wherein the object is a cylindrical object, and the guide is configured to illuminate a cylindrical surface of the cylindrical object from an oblique direction with respect to its normal line with rectangular light that is long in a direction parallel to a cylinder axis of the cylindrical object.