Image display apparatus

• US 6,252,728 B1
• Filed: 10/21/1999
• Issued: 06/26/2001
• Est. Priority Date: 01/29/1999
• Status: Active Grant

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Togino, Takayoshi
• Primary Examiner(s): Spyrou, Cassandra
• Assistant Examiner(s): Treas, Jared
• Application Number:
  US09/422,472
• Time in Patent Office: 614 Days
• Field of Search: 359/833, 359/834, 359/631, 359/630, 359/720
• US Class Current: 359/834
• CPC Class Codes: G02B 13/06 Panoramic objectives; So-called "sky lenses" including panoramic objectives having reflecting surfaces
• CPC Class Codes: G02B 17/0832 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 17/0848 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

Abstract

The invention relates to a slimmed-down, well weight-balanced image display apparatus which, while a wide angle of view is presented, ensures high resolving power and a large pupil diameter, and comprises a viewing optical system for viewing an image displayed on an image display device 3 and having generally positive refracting power. The viewing optical system comprises a relay optical element for forming a relay image 6 and an ocular optical element for forming an exit pupil 2 for guiding relay image 6 to an observer. The relay optical element comprises a prism member 5. The prism member 5 comprises an entrance surface 11, at least one reflecting surface 12 or 13, and an exit surface 14. The reflecting surface is constructed of a rotationally asymmetric surface capable of imparting power to a light beam and making correction for aberrations produced by decentration. The ocular optical element is constructed of a concave mirror 4 having a rotationally asymmetric surface capable of imparting power to a light beam and making correction for aberrations produced by decentration.

Claims

1. An image display apparatus comprising an image display device and a viewing optical system which forms an exit pupil for viewing an image displayed on said image display device and has generally positive refractive power, wherein:

said viewing optical system comprises a relay optical element constructed and arranged to form said image in the form of a relay image and an ocular optical element constructed and arranged to form an exit pupil for guiding said relay image to an observer,

said relay optical element comprising a prism member formed of a medium having a refractive index n that is n>

1,

said prism member comprising an entrance surface through which a light beam leaving said image display device enters a prism, at least one reflecting surface at which said light beam is reflected within said prism, and an exit surface through which said light beam leaves said prism, with said, at least one reflecting surface having a curved surface shape capable imparting power to said light beam, said curved surface is defined by a rotationally asymmetric surface to correct aberrations produced by decentration, and

said ocular optical element including at least one concave mirror located between said exit surface of said prism member and a viewing side, said concave mirror being defined by a rotationally asymmetric curved surface adapted to impart optical power on said light beam upon reflection and to correct aberrations produced by decentration.

2. An image display apparatus according to claim 1, wherein said prism member comprises at least two reflecting surfaces, each having a rotationally asymmetric curved surface shape adapted to impart optical power on a light beam and to correct aberrations produced by decentration.

3. The image display apparatus according to claim 2, wherein said prism member comprises a first surface that is an entrance surface and reflects a light beam within said prism, said light beam being reflected at a second surface within said prism, a second surface that reflects a light beam incident from said first surface on said prism, and a third surface that allows said light beam reflected at said second surface to leave said prism.

4. The image display apparatus according to claim 3, wherein both said first surface and said second surface are designed to have a rotationally asymmetric surface shape capable of imparting power to the light beam and making correction for aberrations produced by decentration.

5. The image display apparatus according to claim 3 or 4, wherein said third surface is designed to have a rotationally asymmetric surface shape capable of imparting power to the light beam and making correction for aberrations produced by decentration.

14. The image display apparatus according to any one of claims 1 to 4, 6, 7, 9 and 10, wherein rotationally asymmetric surfaces of said prism member and said concave image are each defined by a free form surface symmetric with respect to a plane, said free-form surface shape having only one symmetric plane.

15. The image display apparatus according to claim 14, wherein said only one symmetric plane of each of said free-form surfaces is formed on the same plane.

16. The image display apparatus according to any one of claims 1 to 4, 6, 7, 9 and 10, wherein said concave mirror in said ocular optical element is made up of a half coated mirror capable of observing an outside world.

17. The image display apparatus according to any one of claims 1 to 4, 6, 7, 9 and 10, wherein said concave mirror in said ocular optical element is made up of a diffraction type optical element or hologram capable of observing an outside world.

18. The image display apparatus according to any one of claims 1 to 4, 6, 7, 9 and 10, wherein said image display apparatus satisfies the following condition:

19. The image display apparatus according to any one of claims 1 to , 6, 7, 9 and 10 wherein said image display apparatus satisfies at least one of the following conditions:

20. The image display apparatus according to any one of claims 1 to 4, 6, 7, 9 and 10 wherein said image display apparatus satisfies at least one of the following conditions:

21. The image display apparatus according to any one of claims 1 to 4, 6, 7, 9 and 10 wherein said image display apparatus satisfies the following condition:

6. An image display apparatus comprising an image display device and a viewing optical system which forms an exit pupil for viewing an image displayed on said image display device and has generally positive refractive power, wherein:

said viewing optical system comprises a relay optical element constructed and arranged to form said image in the form of a relay image and an ocular optical element constructed and arranged to form an exit pupil for guiding said relay image to an observer,

said relay optical element comprising a prism member formed of a medium having a refractive index n that is n>

1,

said prism member comprising an entrance surface through which a light beam leaving said image display device enters said prism, at least one reflecting surface at which said light beam is reflected within said prism, and an exit surface through which said light beam leaves said prism, with said, at least one reflecting surface having a curved surface shape capable imparting power to said light beam, said curved surface is defined by a rotationally asymmetric surface to correct aberrations produced by decentration,

said ocular optical element including at least one concave mirror located between said exit surface of said prism member and a viewing side, said concave mirror being defined by a rotationally asymmetric curved surface adapted to impart optical power on said light beam upon reflection and to correct aberrations produced by decentration,

said prism member comprises at least two reflecting surfaces, each having a rotationally asymmetric curved surface shape adapted to impart optical power on a light beam and to correct aberrations produced by decentration,

said prism member comprises at least four optical action surfaces including a first surface that is said entrance surface, a second surface that reflects a light beam within the prism, a third surface that reflects the light beam within the prism and a fourth surface that is said exit surface,

said first surface and said second surface being opposed to each other with a medium located therebetween,

said third surface and said fourth surface being opposed to each other with a medium located therebetween, and

an optical path for connecting said first surface with said second surface intersecting an optical path for connecting said third surface with said fourth surface.

7. The image display apparatus according to claim 6, wherein both said second surface and said third surface are designed to have a rotationally asymmetric surface shape capable of imparting power to the light beam and making correction for aberrations produced by decentration.

8. The image display apparatus according to claim 6 or 7, wherein at least one of said first surface and said fourth surface has a rotationally asymmetric surface shape capable of imparting power to the light beam and making correction for aberrations produced by decentration.

9. An image display apparatus comprising an image display device and a viewing optical system which forms an exit pupil for viewing an image displayed on said image display device and has generally positive refractive power, wherein:

said viewing optical system comprises a relay optical element constructed and arranged to form said image in the form of a relay image and an ocular optical element constructed and arranged to form an exit pupil for guiding said relay image to an observer,

said relay optical element comprising a prism member formed of a medium having a refractive index n that is n>

1,

said prism member comprising an entrance surface through which a light beam leaving said image display device enters the prism, at least one reflecting surface at which said light beam is reflected within said prism, and an exit surface through which said light beam leaves said prism, with said at least one reflecting surface having a curved surface shape capable imparting power to said light beam, said curved surface is defined by a rotationally asymmetric surface to correct aberrations produced by decentration,

said ocular optical element including at least one concave mirror located between said exit surface of said prism member and a viewing side, said concave mirror being defined by a rotationally asymmetric curved surface adapted to impart optical power on said light beam upon reflection and to correct aberrations produced by decentration,

said prism member comprises at least two reflecting surfaces, each having a rotationally asymmetric curved surface shape adapted to impart optical power on a light beam and to correct aberrations produced by decentration,

said prism member comprises at least five optical action surfaces including a first surface that is said entrance surface, a second surface that reflects a light-beam within a prism, a third surface that reflects a light beam within the prism, a fourth surface that reflects a light beam within the prism and a fifth surface that is said exit surface,

said second surface and said third surface being opposed to each other with a medium located therebetween,

said fourth surface and said fifth surface being opposed to each other with a medium located therebetween, and

an optical path for connecting said second surface with said third surface intersecting an optical path for connecting said fourth surface with said fifth surface.

10. The image display apparatus according to claim 9, wherein both said third surface and said fourth surface are designed to have a rotationally asymmetric surface shape capable of imparting power to the light beam and making correction for aberrations produced by decentration.

11. The image display apparatus according to claim 9 or 10, wherein said second surface has a rotationally asymmetric surface shape adapted to impart optical power on the light beam and to correct aberrations produced by decentration.

12. The image display apparatus according to claim 10, wherein said second, third, and fourth surfaces each have positive power.

13. The image display apparatus according to claim 9 or 10, wherein at least one of said first surface and said fifth surface is designed to have a rotationally asymmetric surface shape adapted to impart optical power on the light beam and to correct aberrations produced by decentration.