Display device

Patent metadata

Field	Value
Publication number	US-10613265-B2
Application number	US-201716342272-A
Country	US
Kind code	B2
Filing date	Nov 20, 2017
Priority date	Mar 14, 2017
Publication date	Apr 7, 2020
Grant date	Apr 7, 2020

Abstract

Provided is a display device that prevents generation of stray light and has excellent visibility. In a display device ( 1 ) that makes an image light ray enter from an end face of a light guide plate ( 14 ) and emits the image light ray, reflected or refracted by each of a plurality of emission structures (prisms 141 ) provided on the light guide plate, from a light exit surface ( 14 c ) of the light guide plate, a light reflection layer or a light absorption layer is formed on at least one optical surface among optical surfaces provided on the emission structure (the prism 141 ) except for an optical surface that reflects or refracts the image light ray.

First claim

The invention claimed is:

1. A display device comprising:
a light guide plate; and
another light plate that has a shape fitted with a bottom surface facing the light exit surface of the light guide plate, and that is joined to the light guide plate; and
a mask that has a plurality of slits, from where a light ray is transmitted through; and
a light reflection layer or a light absorption layer that is formed on at least one optical surface among optical surfaces in the emission structure except for an optical surface that reflects or refracts the image light ray,
wherein the display device makes an image light ray enter from an end face of the light guide plate and emits the image light ray, reflected or refracted by each of a plurality of emission structures provided on the light guide plate, from a light exit surface of the light guide plate.

2. The display device according to claim 1 , wherein the image light ray propagating inside the light guide plate is reflected twice or more by at least one of the light exit surface and a bottom surface facing the light exit surface and then emitted from the light exit surface.

3. The display device according to claim 2 , wherein a refractive index of the other light guide plate is different from a refractive index of the light guide plate.

4. The display device according to claim 3 , wherein the refractive index of the other light guide plate is smaller than the refractive index of the light guide plate.

5. The display device according to claim 1 , wherein the emission structure is formed on the light exit surface of the light guide plate so as to have a convex shape toward an outside of the light guide plate.

6. The display device according to claim 1 , wherein the emission structure is formed on a bottom surface of the light guide plate so as to have a convex shape toward the outside of the light guide plate.

7. The display device according to claim 1 , wherein the light reflection layer is formed on a surface among the optical surfaces provided in the emission structure, the surface being on a side closer to an incident surface with respect to a light guiding direction, and metal particles or nonmetal particles are evaporated on the surface.

8. The display device according to claim 1 , wherein the light reflection layer is formed on a surface among the optical surfaces provided in the emission structure, the surface being on a side farther from an incident surface with respect to a light guiding direction, and metal particles or nonmetal particles are evaporated on the surface.

9. The display device according to claim 1 , wherein the light reflection layer is formed of a metal thin film having a high reflectance.

10. The display device according to claim 1 , wherein the light absorption layer is formed of a black paint that absorbs a light ray.

11. The display device according to claim 1 , wherein the other light guide plate has a refractive index same as a refractive index of the light guide plate,
the display device further comprising a semi-transmissive layer between the light guide plate and the other light guide plate, the semi-transmissive layer transmitting some of incident light rays.

12. The display device according to claim 1 , wherein
the other light guide plate has a refractive index same as a refractive index of the light guide plate,
the display device further comprising a light transmission layer between the light guide plate and the other light guide plate, the light transmission layer having a refractive index different from the refractive index of the light guide plate.

13. The display device according to claim 1 , further comprising:
an image display device configured to output an image light ray by displaying an image in a display region;
a collimator lens disposed between the image display device and an incident surface of the light guide plate and configured to collimate the image light ray in a direction orthogonal to a longitudinal direction of the incident surface; and
an imaging lens disposed between the image display device and the incident surface and configured to form an image by the image light ray at a predetermined position with respect to a direction parallel to the longitudinal direction of the incident surface,
wherein the plurality of emission structures respectively emits light rays, emitted from positions different from each other in the direction orthogonal to the longitudinal direction of the incident surface in the display region, from the light exit surface toward a predetermined viewpoint, the light exit surface being one surface of the light guide plate.

Assignees

• Omron Tateisi Electronics Co

Inventors

• Shinohara Masayuki
• Kurata Gouo
• Kitamura Norikazu
• Arai Tsuyoshi
• Mori Yuto

Classifications

• G02B27/0018

  with means for preventing ghost images (anti-reflection coatings G02B1/11) · CPC title

• G02F1/13

  based on liquid crystals, e.g. single liquid crystal display cells · CPC title

• G02B5/10

  with curved faces · CPC title

• G02B30/56

  by projecting aerial or floating images · CPC title

• G02B6/0038

  Linear indentations or grooves, e.g. arc-shaped grooves or meandering grooves, extending over the full length or width of the light guide · CPC title