Head mount type display device

• US 20010010598A1
• Filed: 01/30/2001
• Published: 08/02/2001
• Est. Priority Date: 01/31/2000
• Status: Active Grant

• Current Assignee: Google LLC (Alphabet Inc.)
• Original Assignee: Fujitsu Limited
• Inventors: Saito, Seiichi, Aritake, Hirokazu, Tomita, Junji
• Granted Patent: US 6,690,516 B2
• Time in Patent Office: Days
• US Class Current: 359/630
• CPC Class Codes: G02B 2027/0178 Eyeglass type eyeglass details G02C
• CPC Class Codes: G02B 27/0172 characterised by optical features
• CPC Class Codes: G02B 5/30 Polarising elements light-modulating devices with active elements G02F1/00

Abstract

The head mount type display device includes an optical system having a light emitting element, a display element illuminated by the light emitting element, and an image forming element 20 for producing an image. The display element is arranged between the image forming element and the first focal point of the image forming element at a position nearer to the first focal point of the image forming element. A virtual image of the display element is formed by the image forming element 20 and the light emitted by the light emitting element is focussed on a second focal point of the image forming element. It is designed such that the eye of an observer is located on the second focal point when use. In another form, the optical system includes first and second elliptical concave mirrors with respective ones of focal points arranged at a common position.

Claims

1. A display device arranged in front of an eye of an observer, comprising:

a light emitting element;

a display element illuminated by said light emitting element; and

an image forming element allowing light passing through said display element to pass therethrough;

wherein said display element is arranged between said image forming element and a first focal point of said image forming element at a position near to said first focal point of said image forming element, whereby a virtual image of said display element is formed by said image forming element, and the light emitted from said light emitting element is focussed at a second focal point of said image forming element.

2. A display device according to

claim 1

, further comprising an optical element arranged between said light emitting element and said display element for converting the light incident to said display element into a parallel light.

3. A display device according to

claim 2

, wherein the display element is a transmission type display element, the optical element is arranged on one side of the display element, and the image forming element is arranged on the other side of the display element.

4. A display device according to

claim 2

, wherein the display element is a reflection type display element, and the optical element and the image forming element are formed by a common element.

5. A display device comprising:

a display element;

an image forming element;

a first concave mirror formed as a part of a first elliptical member having a first focal point through which light emitted from said display element and passing through said image forming element passes, and a second focal point; and

a second concave mirror formed as a part of a second elliptical member having a third focal point arranged at a position common to said second focal point and a fourth focal point;

wherein the light emitted from said display element is focussed on or near said first focal point, the light passing through said first focal point is reflected by said first concave mirror and proceeds toward the second and third common focal points, and the light passing through said second and third focal points or the light equivalent thereto is reflected by said second concave mirror and focussed on or near said fourth focal point, so that an eye of an observer can be arranged in the neighborhood of said fourth focal point to see an image on display formed in front of the eye of the observer.

6. A display device according to

claim 5

, wherein said first concave mirror and said second concave mirror are arranged in a light guide member.

7. A display device according to

claim 5

, wherein the first focal point, the second focal point, the third focal point, and the fourth focal point are located on a straight line.

8. A display device according to

claim 5

, wherein the first focal point, the second focal point, the third focal point and the fourth focal point are not located on a straight line.

9. A display device according to

claim 5

, wherein said second concave mirror is optically transparent.

10. A display device arranged in front of an eye of an observer, comprising:

a light emitting element;

a display element illuminated by said light emitting element; and

an image forming element allowing light passing through said display element to pass therethrough;

wherein said display element is arranged between said image forming element and a first focal point of said image forming element at a position near to said first focal point of said image forming element, whereby a virtual image of said display element is formed by said image forming element, and the light emitted from said light emitting element is focussed at a second focal point of said image forming element; and

wherein said device further comprises;

a first concave mirror formed as a part of a first elliptical member having a third focal point common to said second focal point of said image forming element and a fourth focal point; and

a second concave mirror formed as a part of a second elliptical member having a fifth focal point arranged at a position common to said fourth focal point and a sixth focal point;

wherein the light emitted from said display element is focussed on or near said third focal point, the light passing through said third focal point is reflected by said first concave mirror and proceeds toward said fourth and fifth common focal points, the light passing through said fourth and fifth focal points or the light equivalent thereto is reflected by said second concave mirror and focussed on or near said sixth focal point, so that the eye of the observer can be arranged on or near said sixth focal point to see an image on display formed in front of the eye of the observer.

11. A display device arranged in front of an eye of an observer, comprising:

a display element;

an image forming element for focussing light emitted from said display element;

a light guide member having an incident surface to which the light passing through said image forming element is made incident; and

a concave mirror arranged on said light guide member for receiving the light passing through said light guide member;

wherein said concave mirror is formed as a part of an elliptical member having a first focal point and a second focal point, so that the light passing through said image forming element is reflected a plurality of times in said light guide member and made incident to said concave mirror in a manner as if the light is made incident to said concave mirror from the second focal point P2, and the light reflected by said concave mirror was focussed on or near said first focal point, thereby entering the eye of the observer.

12. A display device according to

claim 11

, wherein said light guide member has a pair of flat surfaces in opposed relation to each other and an inclined surface at an angle to said flat surfaces, and the light passing through said image forming element is focussed on said inclined surface and reflected by said pair of said flat surfaces in opposed relation to each other.

13. A display device arranged in front of an eye of an observer, comprising:

a display element;

an optical element for converting light illuminating said display element or light passing through said display element into substantially parallel light; and

a concave mirror to which the light passing through said optical element is made incident;

wherein said concave mirror is formed as a part of a paraboloid of revolution, and the light reflected by said concave mirror is focussed on or near a focal point of said paraboloid of revolution, thereby entering the eye of the observer.

14. A display device according to

claim 13

, wherein said optical element further includes a concave mirror formed as a part of a paraboloid of revolution.

15. A display device according to

claim 14

, wherein said concave mirror and said another concave mirror are arranged on a light guide member.