BACKLIGHT UNIT AND HEAD-UP DISPLAY DEVICE

• US 20200132991A1
• Filed: 09/30/2019
• Published: 04/30/2020
• Est. Priority Date: 10/26/2018
• Status: Active Application

• Current Assignee: Yazaki Corporation
• Original Assignee: Yazaki Corporation
• Inventors: Narushima, Noriaki
• Application Number:
  US16/588,579
• Publication Number:
  US 20200132991A1
• Time in Patent Office: Days
• CPC Class Codes: G02B 27/01 Head-up displays
• CPC Class Codes: G02B 3/00 Simple or compound lenses
• CPC Class Codes: G02B 5/02 Diffusing elements; Afocal elements
• CPC Class Codes: G02F 1/13306 Circuit arrangements or driving methods for the control of single liquid crystal cells G02F1/132, G02F1/133382 take precedence
• CPC Class Codes: G02F 1/133504 Diffusing, scattering, diffracting elements associated to illuminating devices G02F1/133606
• CPC Class Codes: G02F 1/133526 Lenses, e.g. microlenses or Fresnel lenses
• CPC Class Codes: G02F 1/133528 Polarisers
• CPC Class Codes: G02F 1/133555 Transflectors
• CPC Class Codes: G02F 1/133603 with LEDs
• CPC Class Codes: G02F 1/133606 including a specially adapted diffusing, scattering or light controlling members
• CPC Class Codes: G02F 1/133607 the light controlling member including light directing or refracting elements, e.g. prisms or lenses
• CPC Class Codes: G02F 1/133615 Edge-illuminating devices, i.e. illuminating from the side

Abstract

A backlight unit includes a light source and a lens that has an incident surface facing the light source and an emission surface that is a surface on the opposite side to the incident surface and faces a liquid crystal display unit of a light transmission type, and has a shape of condensing light incident on the incident surface from the light source toward the liquid crystal display unit. The lens is configured with a transparent layer and a diffusion layer for diffusing light placed on top of each other between the incident surface and the emission surface. The diffusion layer covers an entire surface of the transparent layer on the liquid crystal display unit side.

Claims

1. A backlight unit comprising:

a light source; and

a lens that includes an incident surface facing the light source and an emission surface that is a surface on an opposite side to the incident surface and faces a liquid crystal display unit of a light transmission type, and has a shape of condensing light incident on the incident surface from the light source toward the liquid crystal display unit, wherein

the lens is configured with a transparent layer and a diffusion layer that diffuses light placed on top of each other between the incident surface and the emission surface, and

the diffusion layer covers an entire surface of the transparent layer on the liquid crystal display unit side.

2. The backlight unit according to claim 1, wherein

the transparent layer and the diffusion layer are integrally molded.

3. The backlight unit according to claim 1, wherein

the emission surface is configured with the diffusion layer.

4. The backlight unit according to claim 2, wherein

the emission surface is configured with the diffusion layer.

5. The backlight unit according to claim 3, wherein

a thickness of the diffusion layer constituting the emission surface is uniform.

6. The backlight unit according to claim 4, wherein

a thickness of the diffusion layer constituting the emission surface is uniform.

7. The backlight unit according to claim 1, wherein

the incident surface is configured with the diffusion layer.

8. The backlight unit according to claim 2, wherein

the incident surface is configured with the diffusion layer.

9. The backlight unit according to claim 3, wherein

the incident surface is configured with the diffusion layer.

10. The backlight unit according to claim 5, wherein

the incident surface is configured with the diffusion layer.

11. The backlight unit according to claim 7, wherein

a thickness of the diffusion layer constituting the incident surface is uniform.

12. The backlight unit according to claim 1, wherein

the incident surface is configured with the transparent layer.

13. The backlight unit according to claim 2, wherein

the incident surface is configured with the transparent layer.

14. The backlight unit according to claim 3, wherein

the incident surface is configured with the transparent layer.

15. The backlight unit according to claim 5, wherein

the incident surface is configured with the transparent layer.

16. The backlight unit according to claim 1, wherein

a shape of the transparent layer is a shape for condensing light incident on the transparent layer from the light source side toward the liquid crystal display unit.

17. The backlight unit according to claim 2, wherein

a shape of the transparent layer is a shape for condensing light incident on the transparent layer from the light source side toward the liquid crystal display unit.

18. The backlight unit according to claim 3, wherein

a shape of the transparent layer is a shape for condensing light incident on the transparent layer from the light source side toward the liquid crystal display unit.

19. The backlight unit according to claim 5, wherein

a shape of the transparent layer is a shape for condensing light incident on the transparent layer from the light source side toward the liquid crystal display unit.

20. A head-up display device comprising:

a liquid crystal display unit of a light transmission type; and

a backlight unit, wherein

the backlight unit includes

a light source, and

a lens that includes an incident surface facing the light source and an emission surface that is a surface on an opposite side to the incident surface and faces the liquid crystal display unit, and has a shape of condensing light incident on the incident surface from the light source toward the liquid crystal display unit,

the lens is configured with a transparent layer and a diffusion layer that diffuses light placed on top of each other between the incident surface and the emission surface, and

the diffusion layer covers an entire surface of the transparent layer on the liquid crystal display unit side.