Lighting apparatus and image pickup apparatus

• US 20020186972A1
• Filed: 04/23/2002
• Published: 12/12/2002
• Est. Priority Date: 05/10/2001
• Status: Active Grant

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Tenmyo, Yoshiharu
• Granted Patent: US 6,850,375 B2
• Time in Patent Office: Days
• US Class Current: 396/175
• 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 provided with a reflecting surface to reflect light from said light source forward;

wherein said optical member includes a plurality of pairs of said reflecting surfaces arranged on both sides of the optical axis within a plane including the radial direction of said light source in the direction perpendicular to the optical axis.

2. The lighting apparatus according to claim 1,

wherein said optical member comprises a prism section provided with a refracting surface that receives light incident from said light source and a reflecting surface that reflects the light incident from the refracting surface, and

a plurality of pairs of said prism sections are formed on said optical member, arranged on both sides of the optical axis within the plane including the radial direction of said light source in the direction perpendicular to the optical axis.

3. The lighting apparatus according to claim 1, wherein a lens section having positive refracting power is formed on and close to the optical axis on the entrance surface side of said optical member and said plurality of reflecting surface pairs is formed in the peripheral section.

4. The lighting apparatus according to claim 1,

wherein said light source has a cylindrical shape, and

a prism array having refracting power in the longitudinal direction of said light source is formed on the exit surface side of said optical member.

5. The lighting apparatus according to claim 1, wherein said reflecting surface is a curved surface.

6. The lighting apparatus according to claim 2, wherein an edge in said light source side formed by an intersection between said refracting surface and said reflecting surface of each of prism section is located closer to said light source side for a prism section which is farther from the optical axis in the direction perpendicular to the optical axis within the plane including the radial direction of said light source.

7. The lighting apparatus according to claim 2, wherein said edges of a pair of prism sections of said plurality of prism section pairs, farthest from the optical axis within the plane including the radial direction of said light source in the direction perpendicular to the optical axis is placed substantially in the same position as the center position of said light source in the direction of the optical axis.

8. The lighting apparatus according to claim 2, further comprising a reflection member which is placed behind said light source and which reflects light from said light source forward,

wherein said reflection member extends to a position to cover at least part of the reflecting surface of a pair of prism sections of said plurality pairs of prism sections, farthest from the optical axis within the plane including the radial direction of said light source in the direction perpendicular to the optical axis.

9. The lighting apparatus according to claim 3, wherein each of said reflecting surface is shaped in such a way that the irradiation range of light irradiated through each of said reflecting surface and the irradiation range of light irradiated through said lens section substantially overlap with each other.

10. 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.

11. An image pickup apparatus comprising:

a light source; and

an optical member which is placed in front of said light source and provided with a reflecting surface that reflects light from said light source forward,

wherein a plurality of pairs of said reflecting surfaces is formed on said optical member, arranged on both sides of the optical axis within a plane including the radial direction of said light source in the direction perpendicular to the optical axis.

12. The image pickup apparatus according to claim 11,

wherein said optical member comprises a prism section provided with a refracting surface that receives light incident from said light source and a reflecting surface that reflects the light incident from said refracting surface, and

a plurality of pairs of said prism sections is formed on said optical member, arranged on both sides of the optical axis within the plane including the radial direction of said light source in the direction perpendicular to the optical axis.

13. The image pickup apparatus according to claim 11, wherein a lens section having positive refracting power is formed on and close to the optical axis on the entrance surface side of said optical member and said plurality of reflecting surface pairs is formed in the peripheral section.

14. The image pickup apparatus according to claim 11,

wherein said light source has a cylindrical shape, and

a prism array having refracting power in the longitudinal direction of said light source is formed on the exit surface side of said optical member.

15. The image pickup apparatus according to claim 11, wherein said reflecting surface is a curved surface.

16. The image pickup apparatus according to claim 12, wherein an edge in said light source side formed by an intersection between said refracting surface and said reflecting surface of each prism section is located closer to said light source side for a prism section which is farther from the optical axis in the direction perpendicular to the optical axis within the plane including the radial direction of said light source.

17. The image pickup apparatus according to claim 12, wherein said edges of a pair of prism sections of said plurality of prism section pairs, farthest from the optical axis within the plane including the radial direction of said light source in the direction perpendicular to the optical axis is placed substantially in the same position as the center position of said light source in the direction of the optical axis.

18. The image pickup apparatus according to claim 12, further comprising a reflection member which is placed behind said light source and which reflects light from said light source forward,

wherein said reflection member extends to a position to cover at least part of the reflecting surface of a pair of prism sections of said plurality pairs of prism sections, farthest from the optical axis within the plane including the radial direction of said light source in the direction perpendicular to the optical axis.

19. The image pickup apparatus according to claim 13, wherein each of said reflecting surface is shaped in such a way that the irradiation range of light irradiated through each of said reflecting surface and the irradiation range of light irradiated through said lens substantially overlap with each other.

20. The image pickup apparatus according to claim 11, having a card type configuration.

21. The image pickup apparatus according to claim 11, 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.

22. 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.

23. The lighting apparatus according to claim 22, 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.

24. The lighting apparatus according to claim 22, 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.

25. The lighting apparatus according to claim 22, wherein the reflecting surface of said reflecting section is constructed of a flat surface or curved surface.

26. The lighting apparatus according to claim 22, wherein a pair or a plurality of pairs of said reflecting sections is provided on both sides of the optical axis.

27. The lighting apparatus according to claim 22, 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.

28. The lighting apparatus according to claim 22, 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°

.

29. The lighting apparatus according to claim 22, wherein the area covering said front space of said reflection member is a curved surface of the second order.

30. The lighting apparatus according to claim 22, 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.

31. The lighting apparatus according to claim 22, 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.

32. The lighting apparatus according to claim 22, 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.

33. A lighting apparatus comprising:

a light source;

an optical member which is placed in front of said light source and provided with a lens section having positive refracting power and being placed on and close to the optical axis on the entrance surface side of this optical member;

a first 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 emitted from said light source forward; and

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

34. The lighting apparatus according to claim 33, wherein said second reflection member is constructed of a flat surface or curved surface.

35. The lighting apparatus according to claim 33, wherein a pair or a plurality of pairs of said second reflection members is provided on both sides of the optical axis.

36. The lighting apparatus according to claim 33, wherein said second reflection member is shaped in such a way that the irradiation range of light irradiated through said second reflection member and the irradiation range of light irradiated through said lens section and said first reflection member substantially overlap with each other.

37. The lighting apparatus according to claim 33, wherein an angle α

formed by the light emitted from the center of said light source and incident on said second reflection member with respect to the optical axis is within a range of 20°

≦

α

≦

70°

.

38. The lighting apparatus according to claim 33, wherein said light source has a cylindrical shape and the area of said first reflection member covering the back of said light source is shaped like a semi-cylinder concentric with said light source.

39. The lighting apparatus according to claim 33, wherein the area of said first reflection member covering said front space is a curved surface of second order.

40. The lighting apparatus according to claim 33, wherein the area of said first reflection member covering said front space is a semi-ellipsoidal curved surface whose focal point coincides with the center of said light source.

41. The lighting apparatus according to claim 33, 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.

42. The lighting apparatus according to claim 33, wherein the irradiation range of light emitted from said optical member is made variable by changing a relation of positions between said light source, said optical member and said second reflection member in the direction of the optical axis.

43. An image pickup 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 emitted 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 and 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.

44. The image pickup apparatus according to claim 43, 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.

45. The image pickup apparatus according to claim 43, 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.

46. The image pickup apparatus according to claim 43, wherein the reflecting surface of said reflecting section is constructed of a flat surface or curved surface.

47. The image pickup apparatus according to claim 43, wherein a pair or a plurality of pairs of said reflecting sections is provided on both sides of the optical axis.

48. The image pickup apparatus according to claim 43, wherein the shape of said reflecting section is determined 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.

49. The image pickup apparatus according to claim 43, 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 within a range of 20°

≦

α

≦

70°

.

50. The image pickup apparatus according to claim 43, wherein the area of said reflection member covering said front space is a surface of second order.

51. The image pickup apparatus according to claim 43, wherein the area of said reflection member covering said front space is a semi-ellipsoidal curved surface whose focal point coincides with the center of said light source.

52. The image pickup apparatus according to claim 43, 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.

53. The image pickup apparatus according to claim 43, having a card type configuration.

54. The image pickup apparatus according to claim 43, wherein the irradiation range of light emitted from said optical member is made variable by changing a relation of positions between said light source and said optical member in the direction of the optical axis.

55. An image pickup apparatus comprising:

a light source;

an optical member which is placed in front of said light source and provided with a lens section having positive refracting power and being place on and close to the optical axis on the entrance surface side of this optical member;

a first 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 emitted from said light source forward; and

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

56. The image pickup apparatus according to claim 55, wherein said second reflection member is constructed of a flat surface or curved surface.

57. The image pickup apparatus according to claim 55, wherein a pair or a plurality of pairs of said second reflection members is provided on both sides of the optical axis.

58. The image pickup apparatus according to claim 55, wherein said second reflection member is shaped in such a way that the irradiation range of light irradiated through said second reflection member and the irradiation range of light irradiated through said lens section and said first reflection member substantially overlap with each other.

59. The image pickup apparatus according to claim 55, wherein an angle α

formed by the light emitted from the center of said light source and incident on said second reflection member with respect to the optical axis is within a range of 20°

≦

α

≦

70°

.

60. The image pickup apparatus according to claim 55, wherein said light source has a cylindrical shape and the area of said first reflection member covering the back of said light source is shaped like a semi-cylinder concentric with said light source.

61. The image pickup apparatus according to claim 55, wherein the area of said first reflection member covering said front space is a curved surface of second order.

62. The image pickup apparatus according to claim 55, wherein the area of said first reflection member covering said front space is a semi-ellipsoidal curved surface whose focal point coincides with the center of said light source.

63. The image pickup apparatus according to claim 55, 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.

64. The image pickup apparatus according to claim 55, having a card type configuration.

65. The image pickup apparatus according to claim 55, wherein the irradiation range of light emitted from said optical member and said second reflection member is made variable by changing a relation of positions between said light source, said optical member and said second reflection member in the direction of the optical axis.