Image display apparatus

Patent metadata

Field	Value
Publication number	US-10180574-B2
Application number	US-201615183451-A
Country	US
Kind code	B2
Filing date	Jun 15, 2016
Priority date	Aug 18, 2008
Publication date	Jan 15, 2019
Grant date	Jan 15, 2019

Abstract

An image display apparatus includes an image forming device, a collimating optical system, and an optical device. The optical device includes a light guide plate, a first deflecting member that deflects light incident on the light guide plate, and a second deflecting member that deflects the light, which propagates in the light guide plate by total reflection, a plurality of times. The first and second deflecting members are provided in the light guide plate. Light having one wavelength emitted from at least one pixel satisfies the following condition:

2 t ·sin θ−2≤ W Y ≤2 t ·sin θ+2

where an axial direction of the light guide plate is the Y-direction, W Y prepresents the width in the Y-direction of the light incident on the light guide plate, t represents the thickness of the light guide plate, and θ represents the total reflection angle.

First claim

The application is claimed as follows:

1. An image display apparatus comprising:
an image forming device including a plurality of pixels;
a collimating optical system configured to convert light emitted from the pixels in the image forming device into parallel light; and
an optical device on which the parallel light is incident from the collimating optical system, in which the parallel light is guided, and from which the parallel light is emitted,
wherein the optical device includes a light guide plate including a first deflecting member and a second deflecting member,
wherein at least one of the first deflecting member and the second deflecting member includes a plurality of diffraction grating layers which are arranged at a desired pitch with a desired slant angle, and
wherein the first deflecting member and the second deflecting member are provided in the light guide plate, and wherein the light having a wavelength emitted from at least one of the pixels satisfies the following condition:
2 t ·sin θ−2≤ W Y ≤2 t ·sin θ+2

wherein an axial direction of the light guide plate is a Y-direction, a normal direction of the light guide plate is an X-direction, W Y represents the width in the Y-direction of the light incident on the light guide plate, t represents a thickness of the light guide plate, and θ represents an incident angle of the light, which is totally reflected in the light guide plate, on an inner surface of the light guide plate.

2. The image display apparatus according to claim 1 , wherein the first deflecting member is configured to diffract the light incident on the light guide plate, and the second deflecting member is configured to diffract the light in the light guide plate.

3. The image display apparatus according to claim 2 , wherein the first deflecting member and the second deflecting member include diffraction grating elements.

4. The image display apparatus according to claim 3 , wherein the diffraction grating elements include a reflective diffraction grating element and a transmissive diffraction grating element.

5. The image display apparatus according to claim 1 , wherein the optical system includes at least a convex lens.

6. The image display apparatus according to claim 1 , further comprising:
a scanning member configured to scan light emitted from the optical system; and
a relay optical system configured to relay the light scanned by the scanning member to the optical device.

7. The image display apparatus according to claim 1 , wherein the image forming device is provided at a position corresponding to a focal length of the optical system.

8. The image display apparatus according to claim 1 , wherein the image forming device includes a light source.

9. The image display apparatus according to claim 8 , wherein the light source is a light emitting diode.

10. The image display apparatus according to claim 8 , wherein the image forming device further includes a polarizing beam splitter.

11. The image display apparatus according to claim 1 , wherein the light guide plate includes at least one of a glass or a plastic material.

12. The image display apparatus according to claim 11 , wherein the light guide plate has two substantially parallel surfaces.

13. The image display apparatus according to claim 1 , wherein the light guide plate is transparent.

14. The image display apparatus according to claim 1 , wherein a length of the second deflecting member is different from the first deflecting member.

15. The image display apparatus according to claim 1 , wherein a width of the second deflecting member is different from the first deflecting member.

16. The image display apparatus according to claim 1 , wherein the first deflecting member includes a reflective volume hologram diffraction grating.

17. The image display apparatus according to claim 1 , wherein the first deflecting member and the second deflecting member are provided in the light guide plate.

18. The image display apparatus according to claim 17 , wherein the first deflecting member includes a single layer light reflective film.

19. The image display apparatus according to claim 17 , wherein the diffraction grating layers are formed by forming one diffraction grating layer of an adhesive photopolymer material, and then bonding layers of the adhesive photopolymer material thereon in order.

Assignees

• Sony Corp

Inventors

• Mukawa Hiroshi

Classifications

• G02B26/101

  with both horizontal and vertical deflecting means, e.g. raster or XY scanners (colour television using laser beams scanning a display screen H04N9/3129) · CPC title

• G02B6/0033

  Means for improving the coupling-out of light from the light guide · CPC title

• G02B27/0172 Primary

  characterised by optical features · CPC title

• G02B2027/0112

  comprising device for genereting colour display · CPC title

• G02B5/18

  Diffraction gratings {(holographic optical elements G02B5/32, G03H; integrally combined with optical fibres G02B6/02057; for coupling light guides G02B6/34; integrally combined with optical integrated light guides G02B6/12; grating systems G02B27/44)} · CPC title