Image display device and apparatus

Patent metadata

Field	Value
Publication number	US-10078217-B2
Application number	US-201514885246-A
Country	US
Kind code	B2
Filing date	Oct 16, 2015
Priority date	Oct 24, 2014
Publication date	Sep 18, 2018
Grant date	Sep 18, 2018

Abstract

An image display device includes an image forming unit configured to emit light forming an image; and a concave mirror configured to reflect the light emitted from the image forming unit toward a transparent reflecting member. The image forming unit includes a transparent member on which the image is formed or which forms the image, the transparent member being curved bulging toward the concave mirror.

First claim

What is claimed is:

1. An image display device comprising:
an image forming unit configured to emit light forming an image; and
a concave mirror configured to reflect the light emitted from the image forming unit toward a transparent reflecting member,
wherein the image forming unit includes a transparent member on which the image is formed or which forms the image, the transparent member being curved bulging toward the concave mirror and including a cylindrical shape with a curvature in a lengthwise direction or a crosswise direction.

2. The image display device according to claim 1 , wherein:
0.15≤ R/L≤ 2.0

is satisfied, where L is an optical length of light between center of an intermediate image formed on the transparent member and the concave mirror, the light outgoing from the center of the intermediate image and incident on the concave mirror, R is a curvature radius of the transparent member in one of the lengthwise direction and the crosswise direction.

3. The image display device according to claim 1 , wherein:
0.01≤β/ R≤ 0.7

is satisfied, where β is a value obtained by dividing a length in lateral direction of a virtual image viewed through the transparent reflecting member by a length in the lateral direction of the image, R is a curvature radius of the transparent member in one of the lengthwise direction and the crosswise direction.

4. The image display device according to claim 1 , wherein:
0.01≤α/ R≤ 0.7

is satisfied, where α is a value obtained by dividing a length in longitudinal direction of a virtual image viewed through the transparent reflecting member by a length in the longitudinal direction of the image, R is a curvature radius of the transparent member in one of the lengthwise direction and the crosswise direction.

5. The image display device according to claim 1 , wherein:
0.005≤ R/Limg≤ 0.15

is satisfied, where Limg is a distance from a point of view of an observer viewing a virtual image of the image formed on the transparent member through the transparent reflecting member to the virtual image, R is a curvature radius of the transparent member in one of the lengthwise direction and the crosswise direction.

6. The image display device according to claim 1 , wherein the transparent member has the curvature in the lengthwise direction.

7. The image display device according to claim 1 , wherein the transparent member is a microlens array.

8. The image display device according to claim 1 , wherein light outgoing from center of the image impinges on the concave mirror at a position other than center of the concave mirror.

9. The image display device according to claim 1 , wherein the image forming unit further includes:
a light source unit configured to emit light in accordance with image data,
an optical scanning system including a deflector configured to scan the transparent member with the light emitted from the light source unit, and
no optical member between the deflector and the transparent member.

10. The image display device according to claim 1 , wherein the transparent reflecting member includes a window member of a movable body.

11. The image display device according to claim 1 , further comprising the transparent reflecting member.

12. An apparatus comprising:
the image display device according to claim 1 ; and
a body in which the image display device is mounted.

13. An image display device comprising:
an image forming unit configured to emit light forming an image; and
a concave mirror configured to reflect the light emitted from the image forming unit toward a transparent reflecting member,
wherein the image forming unit includes a transparent member on which the image is formed or which forms the image, the transparent member being curved bulging toward the concave mirror and including a toroidal shape with a curvature in a lengthwise direction.

14. The image display device according to claim 13 , wherein:
the transparent member further has a curvature in a crosswise direction, satisfying
0.8≤ R/R′≤ 2.2

where R is a curvature radius of the transparent member in the lengthwise direction, and R′ is a curvature radius of the transparent member in the crosswise direction.

15. The image display device according to claim 13 , wherein:
0.15≤ R/L≤ 2.0

is satisfied, where L is an optical length of light between center of an intermediate image formed on the transparent member and the concave mirror, the light outgoing from the center of the intermediate image and incident on the concave mirror, and R is a curvature radius of the transparent member in the lengthwise direction.

16. The image display device according to claim 13 , wherein:
0.01≤β/ R≤ 0.7

is satisfied, where β is a value obtained by dividing a length in lateral direction of a virtual image viewed through the transparent reflecting member by a length in the lateral direction of the image, and R is a curvature radius of the transparent member in the lengthwise direction.

17. The image display device according to claim 13 , wherein:
0.01≤α/ R≤ 0.7

is satisfied, where α is a value obtained by dividing a length in longitudinal direction of a virtual image viewed through the transparent reflecting member by a length in the longitudinal direction of the image, and R is a curvature radius of the transparent member in the lengthwise direction.

18. The image display device according to claim 13 , wherein:
0.005≤ R/Limg≤ 0.15

is satisfied, where Limg is a distance from a point of view of an observer viewing a virtual image of the image formed on the transparent member through the transparent reflecting member to the virtual image, and R is a curvature radius of the transparent member in lengthwise direction.

19. The image display device according to claim 13 , wherein the transparent member is a microlens array.

20. An image display device comprising:
an image forming unit configured to emit light forming an image; and
a concave mirror configured to reflect the light emitted from the image forming unit toward a transparent reflecting member,
wherein the image forming unit includes a transparent member on which the image is formed or which forms the image, the transparent member being curved bulging toward the concave mirror and including a freeform surface shape.

Assignees

• Hayashi Yuki
• Nakamura Naoki
• Ichii Daisuke
• Atsuumi Hiromichi
• Miyatake Naoki
• Ricoh Co Ltd

Inventors

• Hayashi Yuki
• Nakamura Naoki
• Ichii Daisuke
• Atsuumi Hiromichi
• Miyatake Naoki

Classifications

• G02B2027/0145

  creating an intermediate image · CPC title

• G02B27/0101 Primary

  characterised by optical features (G02B27/0172 takes precedence) · CPC title

• G02B2027/011

  comprising device for correcting geometrical aberrations, distortion · CPC title

• G02B2027/013

  comprising a combiner of particular shape, e.g. curvature · CPC title

• G02B2027/0118

  comprising devices for improving the contrast of the display / brillance control visibility · CPC title