Image display device and apparatus

• US 10,078,217 B2
• Filed: 10/16/2015
• Issued: 09/18/2018
• Est. Priority Date: 10/24/2014
• Status: Active Grant

• Current Assignee: Ricoh Company Limited
• Original Assignee: Ricoh Company Limited
• Inventors: Hayashi, Yuki, Nakamura, Naoki, Ichii, Daisuke, Atsuumi, Hiromichi, Miyatake, Naoki
• Primary Examiner(s): Ben, Loha
• Application Number:
  US14/885,246
• Publication Number:
  US 20160116735A1
• Time in Patent Office: 1,068 Days
• Field of Search: 359629-632, 345 7- 9
• CPC Class Codes: G02B 2027/011 comprising device for correcting geometrical aberrations, distortion
• CPC Class Codes: G02B 2027/0118 comprising devices for improving the contrast of the display / brillance control visibility
• CPC Class Codes: G02B 2027/013 comprising a combiner of particular shape, e.g. curvature
• CPC Class Codes: G02B 2027/0145 creating an intermediate image
• CPC Class Codes: G02B 27/0101 characterised by optical features G02B27/0172 takes precedence
• CPC Class Codes: G02B 3/0006 Arrays G02B3/02, G02B5/188 take precedence

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.

Claims

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.