Illumination apparatus and image-taking apparatus

• US 20060139481A1
• Filed: 12/14/2005
• Published: 06/29/2006
• Est. Priority Date: 12/28/2004
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kojima, Nobuhisa
• Granted Patent: US 7,581,842 B2
• Time in Patent Office: Days
• US Class Current: 348/371
• CPC Class Codes: H04N 23/56 provided with illuminating means

Abstract

An illumination apparatus having a structure which can make the inside of the apparatus hard to be seen from the outside without deterioration of light distribution, and is applicable to illumination apparatuses having an optical member utilizing total reflection. The illumination apparatus comprises a light-emitting tube extending in a first direction; and an optical member including an entrance portion where a luminous flux from the light-emitting tube enters and an exit portion where the luminous flux exits. The exit portion includes a plurality of surfaces arranged in a second direction orthogonal to the first direction, the surfaces being orthogonal or inclined with respect to the optical axis direction, and located at different positions in the optical axis direction.

Claims

1. An 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 the exit portion includes a plurality of surfaces which are arranged in a second direction orthogonal to the first direction, the surfaces being orthogonal or inclined with respect to the optical axis direction of the illumination apparatus, and located at different positions in the optical axis direction.

2. The illumination apparatus according to claim 1, wherein the plurality of surfaces includes first and second surfaces located at first and second positions, respectively, in the optical axis direction, and

the first and second surfaces are alternately arranged in the second direction in the exit portion.

3. The illumination apparatus according to claim 1, wherein the plurality of surfaces are arranged so that their positions may be changed in one of the optical axis direction.

4. The illumination apparatus according to claim 1, wherein a plane parallel to the optical axis direction is provided between two of the plurality of surfaces, the two surfaces being closest to each other in the second direction.

5. The illumination apparatus according to claim 1, wherein the optical member includes a reflective surface which reflects the luminous flux from the entrance portion in the second direction and leads it to the exit portion.

6. The illumination apparatus according to claim 1, wherein the following condition is satisfied:

a/b≦

0.35

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.

7. An image-taking apparatus comprising:

the illumination apparatus according to claim 1;

and

an image-taking system which takes an image of an object illuminated by the luminous flux from the illumination apparatus.