Optical element, holding structure for optical element, and image pickup apparatus

• US 6,362,921 B1
• Filed: 10/07/1999
• Issued: 03/26/2002
• Est. Priority Date: 01/26/1998
• Status: Expired due to Term

• Current Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Original Assignee: Canon Kabushiki Kaisha (Canon Inc.)
• Inventors: Kawano, Kenji, Iida, Seiji, Uehara, Tsukasa
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): Lucas, Michael A.
• Application Number:
  US09/414,139
• Time in Patent Office: 901 Days
• Field of Search: 359/627, 359/628, 359/630, 359/631, 359/632, 359/633, 359/13, 359/739, 359/819
• US Class Current: 359/627
• CPC Class Codes: G02B 17/0848 off-axis or unobscured systems in which not all of the mirrors share a common axis of rotational symmetry, e.g. at least one of the mirrors is warped, tilted or decentered with respect to the other elements
• CPC Class Codes: G02B 17/086 wherein the system is made of a single block of optical material, e.g. solid catadioptric systems
• CPC Class Codes: G02B 7/02 for lenses supports for magnifying lenses G02B25/002
• CPC Class Codes: H04N 23/54 Mounting of pick-up tubes, electronic image sensors, deviation or focusing coils
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof

Abstract

In an optical element composed of an entrance refractive surface, an exit refractive surface and a plurality of internal reflective surfaces provided between the entrance refractive surface and the exit refractive surface, a structure is provided for enabling the optical element to turn around a reference axis of the entrance refractive surface. Further, in such an optical element, an diaphragm member is disposed adjacent to the entrance refractive surface and is arranged to vary an aperture diameter thereof according to a movement thereof.

Claims

1. An optical apparatus comprising:

an optical element;

a casing accommodating said optical element;

said optical element comprising an entrance refractive surface, an exit refractive surface and a plurality of reflective surfaces provided between said entrance refractive surface and said exit refractive surface, a light flux entering an inside of said optical element at said entrance refractive surface, being reflected a plurality of times at said plurality of reflective surfaces and exiting from said exit refractive surface;

wherein a protruded structure or a recessed structure formed in a circular shape or a cylindrical shape with a center thereof set to a reference axis of the entering light flux is provided adjacent to said entrance refractive surface; and

wherein said casing has an engaging portion engaging with said protruded structure or said recessed structure, said optical element being turnable about the reference relative to said casing.

2. An optical apparatus according to claim 1, wherein said protruded structure or said recessed structure has a plane portion perpendicular to said reference axis.

3. An optical apparatus according to claim 1, wherein a side portion of said protruded structure or recessed structure is formed in parallel with the reference axis.

4. An optical apparatus according to claim 1, wherein said plurality of reflective surfaces include a reflective surface arranged to bend a reference axis of said entrance refractive surface by 90°

.

5. An optical apparatus according to claim 4, wherein a reference axis of said refractive surface is deflected to be perpendicular to the reference axis of said entrance refractive surface.

6. An optical apparatus according to claim 5, wherein a protruded structure of cylindrical shape with a center thereof set to a reference axis of an exiting light flux is provided adjacent to said exit refractive surface.

7. An optical apparatus according to claim 1, wherein said optical element is formed with a transparent body, and at least one surface of said plurality of reflective surfaces is a free curved surface.

8. An optical apparatus according to claim 7, wherein the light flux having entered said entrance refractive surface is imaged as a primary image within said optical element by a power of said entrance refractive surface and a power of at least one of said plurality of reflective surfaces.

9. An optical apparatus according to claim 1, wherein the light flux having entered said refractive surface is imaged as a primary image within said optical element by a power of said entrance refractive surface and a power of at least one of said plurality of reflective surfaces.

10. An optical apparatus according to claim 1, wherein protrusions used for the positioning are respectively provided adjacent to said entrance refractive surface and adjacent to said exit refractive surface.

11. An optical apparatus according to claim 1, wherein a protrusion used for positioning is provided adjacent to said entrance refractive surface.

12. A holding structure for holding an optical element having an entrance refractive surface, an exit refractive surface and a plurality of reflective surfaces provided between said entrance refractive surface and said exit refractive surface, a light flux entering an inside of said optical element at said entrance refractive surface, being reflected a plurality of times at said plurality of reflective surfaces and exiting from said exit refractive surface, said holding structure comprising:

a supporting member which supports said optical element in such a way as to make said optical element turnable for adjustment around a reference axis of an entering light flux at said entrance refractive surface; and

wherein said optical element is provided, adjacent to said entrance refractive surface, with a circular or cylindrical portion with a center thereof set to a reference axis of an entering light flux, and said supporting member comes into contact with said circular or cylindrical portion to make said optical element turnable for adjustment around said reference axis.

13. A holding structure for holding an optical element having an entrance refractive surface, an exit refractive surface and a plurality of reflective surfaces provided between said entrance refractive surface and said exit refractive surface, a light flux entering an inside of said optical element at said entrance refractive surface, being reflected a plurality of times at said plurality of reflective surfaces and exiting from said exit refractive surface, said holding structure comprising:

a supporting member which supports said optical element in such a way as to make a position of said exit refractive surface movable to vary an image forming position of a light flux; and

wherein said optical element is elastically pressed against said supporting member, and a position of said supporting member is changeable by an adjusting operation of an adjustment member, whereby the position of said exit refractive surface is moved to vary the image forming position of the light flux.

14. A holding structure according to claim 13, wherein a contact portion of said supporting member for coming into contact with said optical element is formed in a cam-surface shape.

15. An image pickup apparatus comprising:

an optical element having an entrance refractive surface, an exit refractive surface and a plurality of reflective surfaces provided between said entrance refractive surface and said exit refractive surface, a light flux entering an inside of said optical element at said entrance refractive surface, being reflected a plurality of times at said plurality of reflective surfaces and exiting from said exit refractive surface;

a diaphragm device provided on a light-flux entering side of said entrance refractive surface of said optical element;

an image pickup element provided on a light-flux exiting side of said exit refractive surface of said optical element; and

a case which houses therein said optical element, said diaphragm device and said image pickup element,

wherein an amount of aperture opening of said diaphragm device is varied by a movement of a diaphragm member.

16. An image pickup apparatus according to claim 15, wherein a reference axis of said exit refractive surface of said optical element is deflected to be perpendicular to a reference axis of said entrance refractive surface of said optical element, and said image pickup element is disposed inside said case in such a way as not to overlap with said optical element with respect to a direction of said reference axis of said entrance refractive surface.

17. An image pickup apparatus according to claim 16, further comprising:

a supporting member which supports said optical element in such a way as to make said optical element turnable for adjustment around a reference axis of an entering light flux at said entrance refractive surface.

18. An image pickup apparatus according to claim 16, further comprising:

a supporting member which supports said optical element in such a way as to make a position of said exit refractive surface movable to vary an image forming position of a light flux.

19. An image pickup apparatus according to claim 15, further comprising:

a supporting member which supports said optical element in such a way as to make said optical element turnable for adjustment around a reference axis of an entering light flux at said entrance refractive surface.

20. An image pickup apparatus according to claim 19, wherein said optical element is provided, adjacent to said entrance refractive surface, with a circular or cylindrical portion with a center thereof set to said reference axis of the entering light flux, and said supporting member comes into contact with said circular or cylindrical portion to make said optical element turnable for adjustment around said reference axis of the entering light flux.

21. An image pickup apparatus according to claim 15, further comprising:

a supporting member which supports said optical element in such a way as to make a position of said exit refractive surface movable to vary an image forming position of a light flux.

22. An image pickup apparatus according to claim 21, wherein said optical element is elastically pressed against said supporting member, and a position of said supporting member is changeable by an adjusting operation of an adjustment member, whereby the position of said exit refractive surface is moved to vary the image forming position of the light flux.

23. An image pickup apparatus according to claim 15, wherein said diaphragm member is supported by said case in such a way as to be movable.

24. An image pickup apparatus according to claim 15, wherein said optical element is supported by being pressed against respective supporting members at a position of said entrance refractive surface and a position of said exit refractive surface.

25. An image pickup apparatus comprising:

an optical element having an entrance refractive surface, an exit refractive surface and a plurality of reflective surfaces provided between said entrance refractive surface and said exit refractive surface, a light flux entering an inside of said optical element at said entrance refractive surface, being reflected a plurality of times at said plurality of reflective surfaces and exiting from said exit refractive surface;

a diaphragm device provided on a light-flux entering side of said entrance refractive surface of said optical element;

an image pickup element provided on a light-flux exiting side of said exit refractive surface of said optical element;

a case which houses therein said optical element, said diaphragm device and said image pickup element;

a supporting mechanism which supports said optical element in such a way as to make a position of said exit refractive surface movable to vary an image forming position of a light flux; and

wherein said supporting mechanism includes a supporting member which supports said optical element in such a way as to make said optical element turnable for adjustment around a reference axis of an entering light flux at said entrance refractive surface.

26. An image pickup apparatus according to claim 25, wherein said supporting mechanism includes a supporting member which supports said optical element in such a way as to make a position of said exit refractive surface movable to vary an image forming position of a light flux.

27. An image pickup apparatus according to claim 26, wherein said optical element is elastically pressed against said supporting member, and a position of said supporting member is changeable by an adjusting operation of an adjustment member, whereby the position of said exit refractive surface is moved to vary the image forming position of the light flux.

28. An image pickup apparatus according to claim 25, wherein said optical element is provided, adjacent to said entrance refractive surface, with a circular or cylindrical portion with a center thereof set to a reference axis of an entering light flux, and said supporting member comes into contact with said circular or cylindrical portion to make said optical element turnable for adjustment around said reference axis of the entering light flux.