Patent ID: 8333694

Claim:
An illumination unit comprising: a hollow member having a through opening; a plurality of illumination sections configured to emit illumination light; a holding member which is arranged in the through opening and holds the illumination sections to incline the illumination sections at a desired angle with respect an opening surface of the through opening and to form a cascade along the axial direction of the through opening, wherein the holding member holds the illumination sections in such a manner that the illumination sections form a zigzag pattern in a width direction orthogonal to the axial direction of the through opening without facing each other in the width direction; and a reflective member which is configured to reflect the illumination light emitted from the illumination sections toward the opening surface, the reflective member being held by the holding member to face the illumination sections and to apply the illumination light externally emitted from the illumination sections from the inside of the through opening via the opening surface, or being arranged on an inner surface of the through opening to face the illumination sections and to apply the illumination light externally emitted from the illumination units from the inside of the through opening via the opening surface.