Image pickup optical system comprising a prism fixing member for preventing a deterioration in the capability of correcting decentration abberation, and apparatus therefore

• US 6,704,052 B1
• Filed: 05/10/1999
• Issued: 03/09/2004
• Est. Priority Date: 05/22/1998
• Status: Expired due to Term

• Current Assignee: Olympus Corporation
• Original Assignee: Olympus Corporation
• Inventors: Togino, Takayoshi, Tamagawa, Akira, Aoki, Norihiko
• Primary Examiner(s): Garber, Wendy R.
• Assistant Examiner(s): MISLEH, JUSTIN P
• Application Number:
  US09/307,737
• Time in Patent Office: 1,765 Days
• Field of Search: 359/831, 359/833, 359/834, 359/837, 359/618, 359/619, 359/627, 359/629, 359/630, 359/631, 359/633, 359/637, 359/638, 348/65, 348/208.99, 348/208.1, 348/208.2, 348/208.3, 348/208.4, 348/208.5, 348/208.6, 348/208.7, 348/208.8, 348/335, 348/336, 348/337, 348/338, 348/340, 348/341, 348/342, 348/344, 348/369
• US Class Current: 348/340
• CPC Class Codes: G02B 13/007 the beam folding prism having at least one curved surface
• CPC Class Codes: G02B 13/16 for use in conjunction with image converters or intensifiers , or for use with projectors, e.g. objectives for projection TV
• 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 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0138 comprising image capture systems, e.g. camera
• CPC Class Codes: G02B 23/243 Objectives for endoscopes
• CPC Class Codes: G02B 23/2484 Arrangements in relation to a camera or imaging device processing or control of video signals generated by an endoscope H04N23/60, H04N23/70
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 27/0176 characterised by mechanical features
• CPC Class Codes: G02B 5/04 Prisms
• CPC Class Codes: G02B 7/1805 for prisms G02B7/181 takes precedence
• CPC Class Codes: H04N 23/55 Optical parts specially adapted for electronic image sensors; Mounting thereof

Abstract

The invention relates to an image pickup optical system which can make a sensitive tradeoff between the precision of alignment of a decentration optical prism used as an image formation element for an electronic camera or the like with respect to an image pickup element and ease of fabrication. The invention provides an optical prism 100 comprising three optical surfaces 12 to 14. An entrance surface 14 is suitable for incidence of light from a subject. The incident light is subjected to at least two internal reflections to turn back an optical path. The reflected light leaves the prism through an exit surface 12 to form an image of the subject on an image pickup surface 21 located outside of the prism. At least one of the entrance surface 14 and exit surface 12 is constructed of an optical surface having a combined transmission and internal reflection action. The optical prism is used in combination with a prism frame 30 designed to be well fit therefor. Sides 60L and 60R formed in directions intersecting the directions of the entrance surface 14 and exit surface 12 are provided with protrusions 90L and 90R for mounting the optical prism 100 to the prism frame 30.

Claims

1. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises at least one first prism member,

said first prism member comprises, as optical acting surfaces, at least an entrance surface on which a ray bundle strikes, a reflection surface to reflect said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member, and at least said reflection surface and one of said entrance surface and said exit surface comprise a combined transmission and reflection surface constructed of the same surface,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member configured to fix a position relation between at least said first prism member and said image pickup member, said fixing member being provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration aberration due to a misalignment upon setting.

2. The image pickup optical system according to claim 1 wherein reflection at said combined transmission and reflection surface of said first prism occurs at a total reflection surface.

3. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member and a second prism member,

said first prism member comprises, as optical acting surfaces, at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration,

said second prism member comprises an entrance surface, a reflection surface and an exit surface, at least said reflection surface of said second prism member and one of said entrance surface and said exit surface of said second prism member comprise a combined transmission and reflection surface constructed of the same surface, and

a fixing member to fix a position relation between at least said first prism member and one other optical element is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration due to a misalignment upon setting.

4. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member, and at least one optical element in said plurality of optical elements is fixed to said first prism member and is constructed of a filter,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member to fix a position relation between at least said first prism member and one other optical element is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration due to a misalignment upon setting.

5. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member, a second prism member and a filter, said filter being located between said first prism member and said second prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member to fix a position relation between at least said first prism member and one other optical element provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration due to a misalignment upon setting, and said first prism member, said filter and said second prism member are integrally fixed together by said fixing member.

6. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member, a second prism member and a stop, said stop being located between said first prism member and said second prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member for fixing a position relation between at least said first prism member and one other optical element is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration due to a misalignment upon setting, and said first prism member, said stop and said second prism member are integrally fixed together by said fixing member.

7. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member for fixing position relations among at least said first prism member, one other optical element and said image pickup member is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration aberration due to a misalignment upon setting,

wherein a filter is located between said first prism member and at least one optical element fixed to said first prism member, and said first prism member, said filter and said at least one optical element fixed to said first prism member are integrally fixed together by means of said fixing member.

8. An image pickup optical system comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member,

said first prism member comprises, as optical acting surfaces, at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member constructed to fix position relations among at least said first prism member, one other optical element and said image pickup member, is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration aberration due to a misalignment upon setting,

wherein said fixing member comprises a frame structure having an opening, said image pickup member is located at a position different from that of said opening, said opening is brought into contact with the exit surface or a side surface of said first prism member, so that said first prism member and said image pickup member are mutually fixed to each other.

9. The image pickup optical system according to claim 8, wherein said fixing member comprising said frame structure receives therein said image pickup surface of said image pickup member, and a part of said frame structure is provided with an image pickup surface alignment mechanism for fixing a position of said image pickup surface within said frame structure.

10. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least a first prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member to fix a position relation between at least said first prism member and one other optical element is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration due to a misalignment upon setting,

wherein said fixing member fixing together said first prism member and at least one optical element fixed to said first prism member is constructed of a spacer member connected to a side of said first prism member and a side of said at least one optical element fixed to said first prism member.

11. The image pickup optical system according to claim 10 wherein said spacer member comprises a plurality of rod members located with said first prism and said at least one optical element fixed to said first prism sandwiched therebetween.

12. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises at least one first prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member for fixing a position relation between at least said first prism member and said image pickup member is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration aberration due to a misalignment upon setting,

wherein said rotationally asymmetric curved surface of said first prism member is constructed of a three-dimensional surface that is symmetric with respect to a plane and has only one symmetric plane, and said fixing member is constructed such that a position relation of said first prism member to said image pickup member is fixed thereby locating a center of said image pickup surface of said image pickup member on a plane extending from said symmetric surface of said first prism member.

13. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises at least one first prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration, and

a fixing member for fixing a position relation between at least said first prism member and said image pickup member is provided so as to prevent a deterioration in a capability of said rotationally asymmetric curved reflection surface of said first prism member of correcting decentration aberration due to a misalignment upon setting,

wherein said rotationally asymmetric curved surface of said first prism member is constructed of a three-dimensional surface that is symmetric with respect to a plane and has only one symmetric plane, said image pickup member comprises an image pickup surface in a quadrangular form, and said fixing member is constructed such that a position relation of said first prism member to said image pickup member is fixed, thereby making said fixing member parallel with said symmetric plane of said first prism member and at least one side of said quadrangular form forming said image pickup surface of said image pickup member.

14. The image pickup optical system according claim 13, wherein said image pickup surface of said image pickup member is in a quadrangular form, four internal angles of which are approximately 90°

, and said fixing member is constructed in such a manner that a position relation of said first prism to said image pickup member is fixed thereby making said fixing member parallel with said only one symmetric plane of said first prism and two sides of said quadrangular form forming said image pickup surface of said image pickup member and sandwiching said fixing member between said two sides.

15. The image pickup optical system according to claim 14, wherein said fixing member is constructed in such a manner that a position relation of said first prism to said image pickup member is fixed thereby making said only one symmetric plane of said first prism coincide with a position where said image pickup surface of said image pickup member is symmetric with respect to the horizontal or the vertical.

16. An image pickup optical system, comprising:

an image formation optical system configured to form an object image;

an image pickup member adapted to receive said object image formed by said image formation optical system; and

a holding member constructed and arranged to hold said image pickup member, wherein;

said image formation optical system comprises at least one first prism member,

said first prism member comprises as optical acting surfaces at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration,

said first prism member includes a first coupling mechanism, and

said holding member includes a second coupling mechanism, so that said first and second coupling mechanisms are coupled together to position said first prism member and said image pickup member.

19. A camera device comprising an image pickup optical system as recited in any one of claims 16, 17 and 18,

wherein said image formation optical system is constructed of a phototaking optical system adapted to form an object image for phototaking, and said image pickup member constructed of an image pickup element for phototaking said object image.

20. The camera device according to claim 19, wherein said image pickup element is constructed of an electronic image pickup element, and which further includes recording means for recording said object image received on said electronic image pickup element and a display element for displaying said object image so that said object image can be observed.

21. An endoscope device comprising an image pickup optical system as recited in any one of claims 16, 17 and 18, and further including:

an illumination optical system, and

an observation system,

wherein said image formation optical system is constructed of an objective optical system adapted to form an object image at an observation site, said illumination optical system is configured to illuminate said observation site, and said observation system is configured to observe said object image.

17. An image pickup optical system, comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least one first prism member,

said first prism member comprises, as optical acting surfaces, at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration,

said first prism member includes a first coupling mechanism, and

one of said plurality of optical elements includes a second coupling mechanism, so that said first and second coupling mechanisms are coupled together to position said first prism member and said one of the plurality of optical elements.

18. An image pickup optical system comprising:

an image formation optical system configured to form an object image, and

an image pickup member adapted to receive said object image formed by said image formation optical system, wherein;

said image formation optical system comprises a plurality of optical elements including at least one first prism member,

said first prism member comprises, as optical acting surfaces, at least an entrance surface on which a ray bundle strikes, a reflection surface for reflecting said ray bundle within said first prism member, and an exit surface through which said ray bundle leaves said first prism member,

said reflection surface is constructed in a curved surface form that gives power to said ray bundle, said curved surface being constructed of a rotationally asymmetric curved surface having an action on correction of decentration aberration,

said first prism member includes a first coupling mechanism,

one of said plurality of optical elements includes a second coupling mechanism, and

a spacer member includes a coupling portion configured to couple to said first coupling mechanism and a coupling portion to couple to said second coupling mechanism, so that said first prism member and said one of the plurality of optical elements are positioned via said spacer member.