Lighting apparatus and image pickup apparatus

• US 6,997,571 B2
• Filed: 03/12/2004
• Issued: 02/14/2006
• Est. Priority Date: 05/10/2001
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tenmyo, Yoshiharu
• Primary Examiner(s): SIKDER, MOHAMMAD YUNUS
• Application Number:
  US10/799,263
• Publication Number:
  US 20040170008A1
• Time in Patent Office: 704 Days
• Field of Search: 362/16, 362/3, 362308-314, 362327-331, 362359-360, 362/340, 359831-834, 359/633, 359/642, 359/726
• US Class Current: 362/16
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/0578 Flashtube mounting
• CPC Class Codes: G03B 2215/0582 Reflectors
• CPC Class Codes: G03B 2215/0592 installed in front of light emitter

Abstract

The present invention discloses a lighting apparatus including a light source, an optical member that is placed in front of the light source and provided with a reflecting surface for reflecting light from the light source or prism sections each made up of a refracting surface which receives the light incident from the light source and a reflecting surface for reflecting the light incident from this refracting surface. Here, in the optical member, there is a plurality of pairs of the reflecting surfaces or prism sections arranged in the direction perpendicular to the optical axis within a plane including the radial direction of the light source centered on the optical axis. The present invention can provide a low-profile lighting apparatus using light from the light source with high efficiency.

Claims

1. A lighting apparatus comprising:

a light source;

an optical member which is placed in front of said light source; and

a reflection member which is placed in such a way as to cover the back of said light source and a front space between said light source and said optical member, and reflects light irradiated from said light source forward,

wherein said optical member comprises;

a lens section which is placed on and close to the optical axis on the entrance surface side of said optical member and has positive refracting power; and

a reflecting section which is placed to peripheral side of said lens section, provided closer to the optical axis than the area through which the light reflected by the part of said reflection member covering said front space passes, and reflects light from said light source forward.

2. The lighting apparatus according to claim 1, wherein said reflecting section is shaped like a prism having a refracting surface that receives light incident from said light source and a reflecting surface that reflects light incident from said refracting surface.

3. The lighting apparatus according to claim 1, wherein the refracting surface of said reflecting section is constructed of a flat surface whose gradient with respect to the optical axis is 4°

or less.

4. The lighting apparatus according to claim 1, wherein the reflecting surface of said reflecting section is constructed of a flat surface or curved surface.

5. The lighting apparatus according to claim 1, wherein a pair or plurality of pairs of said reflecting sections is provided on both sides of the optical axis.

6. The lighting apparatus according to claim 1, wherein said reflecting section is shaped in such a way that the irradiation range of light irradiated through said reflecting section and the irradiation range of light irradiated through said lens section and said reflection member substantially overlap with each other.

7. The lighting apparatus according claim 1, wherein an angle α

formed by light emitted from the center of said light source and incident on said reflecting section with respect to the optical axis is included in a range of 20°

≦

α

≦

70°

.

8. The lighting apparatus according to claim 1, wherein the area covering said front space of said reflection member is a curved surface of the second order.

9. The lighting apparatus according to claim 1, wherein the area covering said front space of said reflection member is a semi-ellipsoidal curved surface whose focal point coincides with the center of said light source.

10. The lighting apparatus according to claim 1, wherein said light source has a cylindrical shape and the lens section of said optical member is a cylindrical lens or toric lens having positive refracting power within the plane perpendicular to the longitudinal direction of said light source.

11. The lighting apparatus according to claim 1, wherein the irradiation range of light irradiated from said optical member is made variable by changing a relation of positions in the direction of the optical axis between said light source and said optical member.