Visual display

• US 5,594,588 A
• Filed: 04/23/1993
• Issued: 01/14/1997
• Est. Priority Date: 04/24/1992
• Status: Expired due to Term

• Current Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Original Assignee: Olympus Optical Corporation Limited (Olympus Corporation)
• Inventors: Togino, Takayoshi
• Primary Examiner(s): Epps, Georgia Y.
• Assistant Examiner(s): Robbins, Thomas
• Application Number:
  US08/051,386
• Time in Patent Office: 1,362 Days
• Field of Search: 359/364, 359/631, 359/630, 359/869, 359/839, 359/727, 359/728, 359/13, 359/14
• US Class Current: 359/631
• CPC Class Codes: G02B 5/10 with curved faces
• CPC Class Codes: H04N 5/74 Projection arrangements for image reproduction, e.g. using eidophor

Abstract

A portable visual display which enables observation of an image with minimal distortion includes a two-dimensional display device (7) for displaying an image for observation, and an ocular optical system (6) for projecting an image formed by the two-dimensional display device (7) or a real image thereof in the air as a magnified image and for deviating the optical axis. The ocular optical system (6) is comprised of a concave aspherical mirror. The concave mirror (6) is designed so that the curvature thereof in a direction (X direction) perpendicular to a plane (Y-Z plane) in which the optical axis conventionally increasingly deviates gradually increases in a direction (-Y direction) in which the optical axis is deviated as seen from the observer'"'"'s eye (1). Alternatively, the arrangement may be such that a relay optical system for projecting a real image of the image formed by the two-dimensional image display device (7) in the air is provided, and a part or the whole of the relay optical system is disposed so that the optical axis thereof is inclined toward a direction normal to the object surface away from a straight line connecting the object center and the image center.

Claims

1. A visual display comprising:

a two-dimensional display device for displaying a two-dimensional image for observation;

an ocular optical system having a concave reflecting mirror, said concave reflecting mirror at least partially reflecting said image for observation to form a magnified image as observed by an observer'"'"'s eyeball; and

distortion correcting means for correcting distortion of said magnified image by altering a concavity of said concave reflecting mirror aspherically such that a vertical radius of curvature of said concave reflecting mirror gradually decreases across a horizontal linear direction from a first side of said concave reflecting mirror corresponding to said observer'"'"'s eyeball toward a second side of said concave reflecting mirror corresponding to said two-dimensional display device, said vertical radius of curvature being parallel to a linear direction approximately perpendicular to a plane defined by a reflected optical axis between a center of said display device and a center of said observer'"'"'s eyeball before and after said at least partial reflection by said concave reflecting mirror, said distortion correcting means being formed by a rotationally asymmetric surface of said concave reflecting mirror.

2. A visual display according to claim 1, wherein:

said concave reflecting mirror is disposed such that an angle between said reflected optical axis between said center of said display device and said center of said observer'"'"'s eyeball before said at least partial reflection and said reflected optical axis after said at least partial reflection by said concave reflecting mirror is not smaller than 20 degrees.

3. A visual display according to claim 1, wherein:

said concave reflecting mirror of said ocular optical system is a totally reflecting mirror.

4. A visual display according to claim 1, wherein:

said concave reflecting mirror of said ocular optical system is a concave anamorphic aspherical reflecting mirror.

8. A visual display according to claim 1, 5 or 7, wherein:

said ocular optical system has a focal length in a range of from 30 millimeters to 60 millimeters.

5. A visual display comprising:

a right and a left two-dimensional display device, each of said right and left two-dimensional display devices displaying a respective right and left image for observation by an observer'"'"'s right and left eyes, respectively;

an ocular optical system at least partially reflecting said right and left images for observation as respective right and left magnified images as observed by said observer'"'"'s right and left eyes, respectively; and

right and left distortion correcting means respectively provided in said ocular optical system, for correcting distortion of said respective right and left magnified images directed toward said observer'"'"'s right and left eyes, respectively, said right and left distortion correcting means comprising a reflecting surface with an aspherical configuration in which a radius of curvature of said reflecting surface gradually increases toward said respective right and left two-dimensional display devices from said observer'"'"'s respective right and left eyes in a direction approximately perpendicular to a plane defined by a reflected optical axis between a center of said respective right and left two-dimensional display devices and a center of said observer'"'"'s respective right and left eyes before and after said at at least partial reflection by said reflecting surface;

said right and left two-dimensional display devices being oriented such that an imaginary extension of said optical axis exiting from said right two-dimensional display device passes through said ocular optical system and intersects an imaginary extension of said optical axis exiting from said left two-dimensional display device and passing through said ocular optical system.

6. A visual display according to claim 5, wherein:

said ocular optical system comprises a first independent ocular optical system for said observer'"'"'s right eye and a second independent ocular optical system for said observer'"'"'s left eye.

7. A visual display according to claim 5, wherein:

said right and left distortion correcting means comprises;

right distortion correcting means provided in front of said observer'"'"'s right eye, and

left distortion correcting means provided in front of said observer'"'"'s left eye, said left distortion correcting means being separate from said right distortion correcting means;

said right distortion correcting means and said left distortion correcting means each having a respective radius of curvature which is approximately symmetric with respect to a boundary between said right distortion correcting means and said left distortion correcting means.

9. A visual display according to claim 7, wherein:

said respective radius of curvature of each of said right distortion correcting means and said left distortion correcting means vary toward the right and left of said observer, respectively, in reverse relation to each other.

10. A visual display according to claim 7 or 9, wherein:

said right distortion correcting means and said left distortion correcting means are each formed from a rotationally asymmetric surface.

11. A visual display according to claim 5 or 7, wherein:

said reflecting surface is disposed such that a first angle between a right reflected optical axis between said center of said right two-dimensional display device and said center of said observer'"'"'s right eye, and a second angle between a left reflected optical axis between said center of said left two-dimensional display device and said center of said observer'"'"'s left eye before said at least partial reflection and respective right and left reflected optical axes after said at least partial reflection by said reflecting surface are not smaller than 20 degrees.

12. A visual display comprising:

a two-dimensional display device for displaying a two-dimensional image for observation;

an ocular optical system; and

a concave reflecting mirror, said concave reflecting mirror at least partially reflecting said image for observation to form a magnified image as observed by an observer'"'"'s eyeball, said concave reflecting mirror being rotationally asymmetric such that a radius of curvature of said concave reflecting mirror in a first direction gradually decreases across a linear direction from said observer'"'"'s eyeball.

13. A visual display comprising:

a two-dimensional display device to be disposed beside an observer'"'"'s face; and

an ocular optical system for leading an image formed by said two-dimensional display device to an observer'"'"'s eyeball, said ocular optical system including;

an aspherical surface disposed to face said two-dimensional display device, said aspherical surface satisfying a condition;

space="preserve" listing-type="equation">R.sub.x <

R.sub.y

wherein said R_x is a first paraxial curvature radius of said aspherical surface in an X-Z plane direction perpendicular to an optical axis which is turned back in a Y-Z plane direction, and said R_y is a second paraxial curvature radius of said aspherical surface in said Y-Z plane direction.

15. A visual display according to claim 13 or 14, wherein:

said aspherical surface has at least a reflecting action.

16. A visual display according to claim 13 or 14, wherein:

said aspherical surface has both a reflecting action and a transmitting action.

14. A visual display comprising:

a two-dimensional display device to be disposed beside of an observer'"'"'s face; and

an ocular optical system for leading an image formed by said two-dimensional display device to an observer'"'"'s eyeball, said ocular optical system including;

an aspherical surface having a concave surface directed toward said observer'"'"'s eyeball, said concave surface of said aspherical surface satisfying a condition;

space="preserve" listing-type="equation">R.sub.x <

R.sub.y

wherein said R_x is a first paraxial curvature radius of said concave surface of said aspherical surface in an X-Z plane direction perpendicular to an optical axis which is turned back in a Y-Z plane direction, and said R_y is a second paraxial curvature radius of said concave surface of said aspherical surface in said Y-Z plane direction.