Illumination apparatus and image-taking apparatus

• US 7,581,842 B2
• Filed: 12/14/2005
• Issued: 09/01/2009
• Est. Priority Date: 12/28/2004
• Status: Expired due to Fees

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kojima, Nobuhisa
• Primary Examiner(s): Truong; Bao Q
• Application Number:
  US11/304,405
• Publication Number:
  US 20060139481A1
• Time in Patent Office: 1,357 Days
• Field of Search: 362/16, 362/339, 362/257, 362/317, 362/17, 362/18, 362/217.02, 362/311.01, 362/311.06, 362/333, 362/224, 362/331, 362/332, 362/8, 396/199
• US Class Current: 362/16
• 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 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;

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.

2. 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.