Patent ID: 7581842
Filing Date: 2009-09-01
Classification: H04N

Abstract:
1. An illumination apparatus which is provided in image-taking apparatus, said illumination apparatus comprising: a light-emitting tube which extends in a first direction; and an optical member which includes an entrance portion where a luminous flux from the light-emitting tube enters and an exit portion where the luminous flux exits, wherein said optical member is integrally formed, wherein the exit portion has a plurality of steps that is, in the optical axis direction, most away from said light-emitting tube in said optical member, the steps including first and second surfaces where the luminous flux exits, the first and second surfaces extending in the first direction, being orthogonal to the optical axis direction of the illumination apparatus, and being alternately arranged in the second direction, the second surfaces being, in the optical axis direction, closer to said light-emitting tube than the first surfaces, wherein a plane parallel to the optical axis direction is provided between the first and second surfaces that is closest to each other in the second direction, wherein the optical member includes a reflective surface which reflects the luminous flux from the entrance portion in the second direction and leads the luminous flux to the exit portion, and wherein the following condition is satisfied: where a represents a positional difference between two of the plurality of surfaces, the two surfaces being closest to each other in the second direction, and b represents the width of each of the surfaces in the second direction.