Illumination device

• US 20010028559A1
• Filed: 03/14/2001
• Published: 10/11/2001
• Est. Priority Date: 03/16/2000
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tenmyo, Yoshiharu
• Granted Patent: US 6,575,582 B2
• Time in Patent Office: Days
• US Class Current: 362/16
• CPC Class Codes: F21V 13/04 the elements being reflectors and refractors for vehicle rear lights F21S43/40
• CPC Class Codes: G03B 15/05 Combinations of cameras with electronic flash apparatus; Electronic flash units
• CPC Class Codes: G03B 2215/0507 Pop-up mechanisms
• CPC Class Codes: G03B 2215/0567 Solid-state light source, e.g. LED, laser
• CPC Class Codes: G03B 2215/0578 Flashtube mounting
• CPC Class Codes: G03B 2215/0592 installed in front of light emitter

Abstract

An illumination device or a flash device of a camera includes a light source, a first optical unit and a second optical unit. The first optical unit is arranged to direct light from the light source to an object, and has a lens part disposed a middle portion of the first optical unit and having such an optical power that each of both lens surfaces thereof has a positive refractive power to cause diverging light from the light source to exit in a light-collected state, and reflective surfaces disposed on both sides of the lens part and arranged to reflect light from the light source toward the object. The second optical unit is disposed on a side nearer to the object than the first optical unit and having a plurality of lens parts. An illumination angle is varied by varying a relative interval between the first optical unit and the second optical unit.

Claims

1. An illumination device, comprising:

a light source; and

a first optical unit arranged to direct light from said light source to an object,

wherein said first optical unit has a lens part disposed a middle portion of said first optical unit and having such an optical power that each of both lens surfaces thereof has a positive refractive power to cause diverging light from said light source to exit in a light-collected state, and reflective surfaces disposed on both sides of said lens part and arranged to reflect light from said light source toward the object.

2. An illumination device according to

claim 1

, wherein said first optical unit further has exit surfaces disposed on both sides of said lens part and arranged to cause the light reflected by said reflective surfaces to exit, the light caused to exit being in the light-collected state.

3. An illumination device according to

claim 2

, further comprising a second optical unit having a plurality of positive lens parts of positive refractive power corresponding respectively to light fluxes exiting from said lens part and said reflective surfaces.

4. An illumination device according to

claim 3

, wherein an illumination angle is varied by varying a relative interval between said first optical unit and said second optical unit.

5. An illumination device according to

claim 1

, wherein said light source is a discharge tube of cylindrical form.

6. An illumination device according to

claim 5

, further comprising a reflector disposed on a side of said discharge tube opposite to the object and arranged to return light emitted from said discharge tube toward a light-emitting source of said discharge tube.

7. An illumination device according to

claim 5

, wherein said first optical unit is lengthwise in a longitudinal direction of said discharge tube.

8. An illumination device according to

claim 5

, wherein said lens part of said first optical unit is of cylindrical form.

9. An illumination device according to

claim 1

, wherein each of said reflective surfaces is arranged to totally reflect light.

10. A camera having an illumination device according to

claim 1

mounted thereon.

11. An illumination device, comprising:

a light source;

a first optical unit arranged to direct light from said light source to an object, wherein said first optical unit has a lens part disposed a middle portion of said first optical unit and having such an optical power that each of both lens surfaces thereof has a positive refractive power to cause diverging light from said light source to exit in a light-collected state, and reflective surfaces disposed on both sides of said lens part and arranged to reflect light from said light source toward the object; and

a second optical unit disposed on a side nearer to the object than said first optical unit and having a plurality of lens parts.

12. An illumination device according to

claim 11

, wherein said first optical unit further has exit surfaces disposed on both sides of said lens part and arranged to cause the light reflected by said reflective surfaces to exit, the light caused to exit being in the light-collected state, and wherein said plurality of lens parts of said second optical unit are disposed in such a manner as to correspond respectively to light fluxes exiting from said lens part and said reflective surfaces of said first optical unit.

13. An illumination device according to

claim 11

, wherein an illumination angle is varied by varying a relative interval between said first optical unit and said second optical unit.

14. An illumination device according to

claim 11

, wherein said light source is a discharge tube of cylindrical form.

15. An illumination device according to

claim 14

, further comprising a reflector disposed on a side of said discharge tube opposite to the object and arranged to return light emitted from said discharge tube toward a light-emitting source of said discharge tube.

16. An illumination device according to

claim 14

, wherein said first optical unit is lengthwise in a longitudinal direction of said discharge tube.

17. An illumination device according to

claim 14

, wherein said lens part of said first optical unit is of cylindrical form.

18. An illumination device according to

claim 11

, wherein each of said reflective surfaces is arranged to totally reflect light.

19. A camera having an illumination device according to

claim 11

mounted thereon.