Distortion corrected image display apparatus

• US 5,909,317 A
• Filed: 03/19/1997
• Issued: 06/01/1999
• Est. Priority Date: 03/19/1996
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Togino, Takayoshi, Takahashi, Junko, Nakaoka, Masaya
• Primary Examiner(s): Epps, Georgia
• Assistant Examiner(s): MACK, RICKY LEVERN
• Application Number:
  US08/822,554
• Time in Patent Office: 804 Days
• Field of Search: 359/630, 359/631, 359/633, 345/7, 345/8
• US Class Current: 359/631
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0132 comprising binocular systems
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0025 for optical correction, e.g. distorsion, aberration
• CPC Class Codes: G02B 27/0172 characterised by optical features

Abstract

An image display apparatus corrected for distortions, particularly, a distortion which is asymmetric with respect to the center of the image field. The apparatus includes an image display device (8), and an ocular optical system (42) having a rotationally asymmetric optical surface or a decentered optical surface having a power. The apparatus satisfies the condition of |tan Θ₁ -tan Θ₂ |/tan Θ₁ <0.1, where Θ₁ is an angle made between a light ray emitted from an arbitrary point (44) on the image display device (8) and passing through the center of an exit pupil (40) and a visual axis (41), that is, a straight line connecting the center of an observer'"'"'s pupil and the center of a projected image of the image display device (8), and Θ₂ is an angle made between the visual axis (41) and a light ray emitted from a point (45) which is in point symmetry with the arbitrary point (44) about the center (43) of the image display surface of the image display device (8) and passing through the center of the exit pupil (40).

Claims

1. An image display apparatus comprising:

an image display device; and

an ocular optical system having one of a rotationally asymmetric optical surface and a decentered optical surface having a power;

said image display apparatus satisfying the following conditions;

space="preserve" listing-type="equation">|tan Θ

.sub.1 -tan Θ

.sub.2 |/tan Θ

.sub.1 <

0.1 (1)

where Θ

₁ is an angle made between a light ray emitted from an arbitrary point on said image display device and passing through a center of an exit pupil and a visual axis, that is, a straight line connecting a center of an observer'"'"'s pupil and a center of a projected image of said image display device, and Θ

₂ is an angle made between the visual axis and a light ray emitted from a point which is in point symmetry with said arbitrary point about a center of an image display surface of said image display device and passing through the center of the exit pupils;

said ocular optical system having a prism member, said prism member including an entrance surface through which a bundle of light rays enters said prism member, reflecting surfaces that reflect the rays in said prism member, and an exit surface through which the rays exit from said prism member; and

said reflecting surfaces comprising at least four reflecting surfaces that are arranged to fold an optical path by at least four reflections.

2. An image display apparatus according to claim 1, said image display apparatus satisfying the following condition:

space="preserve" listing-type="equation">|tan Θ

.sub.1 -tan Θ

.sub.2 |/tan Θ

.sub.1 <

0.05 (2).

3. An image display apparatus according to claim 1, said image display apparatus satisfying the following condition:

space="preserve" listing-type="equation">|tan Θ

.sub.1 -tan Θ

.sub.2 |/tan Θ

.sub.1 <

0.025 (3).

7. An image display apparatus according to claim 1 or 4, wherein said ocular optical system leads the image without forming an intermediate image.

8. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has a second surface which is a concave mirror provided to face an observer'"'"'s eyeball at a tilt to the visual axis, and said ocular optical system leads the image without forming an intermediate image.

9. An image display apparatus according to claim 8, which satisfies the following condition:

space="preserve" listing-type="equation">15°

<

φ

.sub.0 <

40°

(7)

where φ

₀ is an incident angle made between a principal ray emitted from a center of said image display device and a line normal to said concave mirror at a point where said principal ray is incident on said concave mirror.

10. An image display apparatus according to claim 8, said image display apparatus satisfying the following condition:

space="preserve" listing-type="equation">20°

<

φ

.sub.0 <

25°

(8)

where φ

₀ is an incident angle made between a principal ray emitted from a center of said image display device and a line normal to said concave mirror at a point where said principal ray is incident on said concave mirror.

11. An image display apparatus according to claim 8, said image display apparatus satisfying the following condition:

space="preserve" listing-type="equation">21°

<

φ

.sub.0 <

24°

(9)

where φ

₀ is an incident angle made between a principal ray emitted from a center of said image display device and a line normal to said concave mirror at a point where said principal ray is incident on said concave mirror.

12. An image display apparatus according to claim 8, wherein said ocular optical system has a configuration that is symmetric with respect to a certain plane and satisfies the following condition:

space="preserve" listing-type="equation">|φ

.sub.1 -φ

.sub.2 |<

15°

(10)

where φ

₁ and φ

₂ are incident angles made between, on the one hand, principal rays emitted from both ends of a section of said image display device taken along said plane and, on the other, lines normal to said concave mirror at respective points where said principal rays are incident on said concave mirror.

13. An image display apparatus according to claim 8, wherein said ocular optical system has a configuration that is symmetric with respect to a certain plane and that satisfies the following condition:

space="preserve" listing-type="equation">|φ

.sub.1 -φ

.sub.2 |<

5°

(11)

where φ

₁ and φ

₂ are incident angles made between, on the one hand, principal rays emitted from both ends of a section of said image display device taken along said plane and, on the other hand, lines normal to said concave mirror at respective points where said principal rays are incident on said concave mirror.

14. An image display apparatus according to claim 8, wherein said ocular optical system has a configuration that is symmetric with respect to a certain plane and that satisfies the following condition:

space="preserve" listing-type="equation">|φ

.sub.1 -φ

.sub.2 |<

2°

(12)

where φ

₁ and φ

₂ are incident angles made between, on the one hand, principal rays emitted from both ends of a section of said image display device taken along said plane and, on the other hand, lines normal to said concave mirror at respective points where said principal rays are incident on said concave mirror.

15. An image display apparatus according to claim 8, wherein said ocular optical system has a configuration that is symmetric with respect to a certain plane and that satisfies the following condition:

space="preserve" listing-type="equation">||φ

.sub.1 -φ

.sub.0 |-|φ

.sub.2 -φ

.sub.0 ||<

2°

(13)

where φ

₁ and φ

₂ are incident angles made between, on the one hand, principal rays emitted from both ends of a section of said image display device taken along said plane and, on the other hand, lines normal to said concave mirror at respective points where said principal rays are incident on said concave mirror, and φ

₀ is an incident angle made between a principal ray emitted from a center of said image display device and a line normal to said concave mirror at a point where said principal ray is incident on said concave mirror.

16. An image display apparatus according to claim 8, wherein said ocular optical system has a configuration that is symmetric with respect to a certain plane and that satisfies the following condition:

space="preserve" listing-type="equation">||φ

.sub.1 -φ

.sub.0 |-|φ

.sub.2 -φ

.sub.0 ||<

0.7°

(14)

where φ

₁ and φ

₂ are incident angles made between, on the one hand, principal rays emitted from both ends of a section of said image display device taken along said plane and, on the other hand, lines normal to said concave mirror at respective points where said principal rays are incident on said concave mirror, and φ

₀ is an incident angle made between a principal ray emitted from a center of said image display device and a line normal to said concave mirror at a point where said principal ray is incident on said concave mirror.

17. An image display apparatus according to claim 8, wherein said ocular optical system has a configuration that is symmetric with respect to a certain plane and that satisfies the following condition:

space="preserve" listing-type="equation">||φ

.sub.1 -φ

.sub.0 |-|φ

.sub.2 -φ

.sub.0 ||<

0.35°

(15)

where φ

₁ and φ

₂ are incident angles made between, on the one hand, principal rays emitted from both ends of a section of said image display device taken along said plane and, on the other hand, lines normal to said concave mirror at respective points where said principal rays are incident on said concave mirror, and φ

₀ is an incident angle made between a principal ray emitted from a center of said image display device and a line normal to said concave mirror at a point where said principal ray is incident on said concave mirror.

18. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has at least three surfaces, said at least three surfaces including a third surface provided to face said image display device, a second surface which is a concave mirror provided to face an observer'"'"'s eyeball at a tilt to the visual axis, and a first surface provided between said second surface and said observer'"'"'s eyeball, wherein light rays emitted from said image display device enter said ocular optical system through said third surface and are reflected by said first surface and then reflected by said second surface, and thereafter, the reflected light rays pass through said first surface to enter said observer'"'"'s eyeball without forming an intermediate image.

19. An image display apparatus according to claim 18, wherein said third surface has a rotationally asymmetric surface configuration.

20. An image display apparatus according to claim 18, wherein said third surface has an asymmetric surface configuration in which it has a positive refracting power in a center thereof, and the positive refracting power weakens or changes to a negative refracting power as a distance from the center of said third surface increases toward a periphery thereof.

21. An image display apparatus according to claim 18, wherein said image display device is tilted with respect to said third surface.

22. An image display apparatus according to claim 18, wherein said image display device is tilted such that a distance between said third surface and an end of said image display device that is remote from said observer'"'"'s eyeball is shorter than a distance between said third surface and an end of said image display device closer to said observer'"'"'s eyeball.

23. An image display apparatus according to claim 18, wherein a center of a surface configuration of said third surface is displaced toward said observer'"'"'s eyeball.

24. An image display apparatus according to claim 18, wherein a center of a surface configuration of said first surface is displaced toward said image display device.

25. An image display apparatus according to claim 18, wherein a center of surface configuration of said first surface is not within an effective area.

26. An image display apparatus according to claim 18, wherein, in said ocular optical system, said third surface has a positive refracting power for light rays transmitted therethrough;

said first surface has a negative refracting power for light rays reflected thereby;

said second surface has a positive refracting power for light rays reflected thereby; and

said first surface has a negative refracting power for light rays transmitted therethrough.

27. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has at least four surfaces, said at least four surfaces including a third surface provided to face said image display device, a second surface which is a concave mirror provided to face an observer'"'"'s eyeball at a tilt to the visual axis, a first surface provided between said second surface and said observer'"'"'s eyeball, and a fourth surface which is a reflecting surface provided to face said second surface, wherein light rays emitted from said image display device enter said ocular optical system through said third surface and are reflected by said fourth surface and then reflected by said second surface, and thereafter, the reflected light rays pass through said first surface to enter said observer'"'"'s eyeball without forming an intermediate image.

28. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has at least three surfaces, wherein light rays emitted from said image display device are reflected at least four times by said at least three surfaces to reach an observer'"'"'s eyeball without forming an intermediate image, and wherein at least one of at least four reflecting surfaces is a concave mirror provided to face said observer'"'"'s eyeball at a tilt to the visual axis.

29. An image display apparatus according to claim 28, wherein said ocular optical system includes, in order from an image display device side thereof, a first transmitting surface, a first reflecting surface, a second reflecting surface, a third reflecting surface, a fourth reflecting surface, and a second transmitting surface, said fourth reflecting surface being a concave mirror provided to face said observer'"'"'s eyeball at a tilt to the visual axis.

30. An image display apparatus according to claim 29, wherein, in said ocular optical system, said first transmitting surface and said second reflecting surface are disposed at the same position and with the same configuration, and said second transmitting surface, said first reflecting surface and said third reflecting surface are disposed at the same position and with the same configuration.

31. An image display apparatus according to claim 29, wherein, in said ocular optical system, said first transmitting surface, said second reflecting surface and said second transmitting surface are disposed at the same position and with the same configuration, and said first reflecting surface and said third reflecting surface are disposed at the same position and with the same configuration.

32. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has a semitransparent surface tilted with respect to the visual axis, and a concave mirror provided to face an observer'"'"'s eyeball, and wherein light rays emitted from said image display device are reflected by said semitransparent surface and then reflected by said concave mirror, and thereafter, the reflected light rays pass through said semitransparent surface to enter said observer'"'"'s eyeball without forming an intermediate image.

33. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has a semitransparent surface tilted with respect to the visual axis, and a concave mirror provided to face said image display device, and wherein light rays emitted from said image display device pass through said semitransparent surface and are reflected by said concave mirror and then reflected by said semitransparent surface to enter an observer'"'"'s eyeball without forming an intermediate image.

34. An image display apparatus according to claim 1 or 4, wherein said ocular optical system uses a beam splitter prism having a semitransparent surface.

35. An image display apparatus according to claim 1 or 4, wherein said ocular optical system has at least four surfaces, said at least four surfaces including a third surface provided to face said image display device, a second surface which is a concave mirror provided to face an observer'"'"'s eyeball at a tilt to the visual axis, a first surface provided between said second surface and said observer'"'"'s eyeball, and a fifth surface which is a reflecting surface provided to face said first surface, and wherein light rays emitted from said image display device enter said ocular optical system through said third surface and are reflected successively by said fifth surface, said first surface and said second surface, and thereafter, said reflected light rays pass through said first surface to enter said observer'"'"'s eyeball without forming an intermediate image.

36. An image display apparatus according to claim 1 or 4, wherein said ocular optical system leads an image to each of observer'"'"'s left and right eyes.

37. An image display apparatus according to claim 1 or 4, further comprising a support member that enables said image display apparatus to be fitted on at least one of an observer'"'"'s head or face.

4. An image display apparatus comprising:

an image display device; and

an ocular optical system;

said image display apparatus satisfying the following condition;

space="preserve" listing-type="equation">|tan Θ

'"'"'.sub.1 -tan Θ

'"'"'.sub.2 |/tan Θ

'"'"'.sub.1 <

0.1 (4)

where Θ

'"'"'₁ is an angle made between a light ray emitted from an arbitrary point on said image display device and passing through an arbitrary point in an exit pupil in which an image is observable, and a visual axis, that is, a straight line connecting a center of an observer'"'"'s pupil and a center of a projected image of said image display device, and Θ

'"'"'₂ is an angle made between the visual axis and a light ray emitted from a point which is in point symmetry with said arbitrary point about a center of an image display surface of said image display device and passing through the arbitrary point in said exit pupil;

said ocular optical system having a prism member, said prism member including an entrance surface through which a bundle of light rays enters said prism member, reflecting surfaces that reflect the rays in said prism member, and an exit surface through which the rays exit from said prism member; and

said reflecting surfaces comprising at least four reflecting surfaces that are arranged to fold an optical path by at least four reflections.

5. An image display apparatus according to claim 4, said image display apparatus satisfying the following condition:

space="preserve" listing-type="equation">|tan Θ

'"'"'.sub.1 -tan Θ

'"'"'.sub.2 |/tan Θ

∝

.sub.1 <

0.05 (5).

6. An image display apparatus according to claim 4, said image display apparatus satisfying the following condition:

space="preserve" listing-type="equation">|tan Θ

'"'"'.sub.1 -tan Θ

'"'"'.sub.2 |/tan Θ

'"'"'.sub.1 <

0.025 (6).