CN217689616U

CN217689616U - Backlight unit, image generation unit, display device, and electronic device

Info

Publication number: CN217689616U
Application number: CN202123386679.7U
Authority: CN
Inventors: 王海国; 俞萍萍; 夏青
Original assignee: Continental Automotive Body Electronic System Wuhu Co Ltd
Current assignee: Continental Automotive Body Electronic System Wuhu Co Ltd
Priority date: 2021-12-29
Filing date: 2021-12-29
Publication date: 2022-10-28
Anticipated expiration: 2031-12-29

Abstract

The utility model provides a backlight unit, including backlight source and light guide plate, the light guide plate is fresnel structure, constitutes the concave lens towards backlight source. The utility model discloses still provide image generation unit, display device and electron device. The utility model provides a backlight unit, image generation unit, display device and electron device, light guide plate are fresnel structure, constitute the concave lens towards backlight source, can reduce image brightness loss like this, promote image brightness uniformity, improve the display quality of image.

Description

Backlight unit, image generation unit, display device, and electronic device

Technical Field

The utility model relates to an automotive filed, concretely relates to backlight unit, image generation unit, display device and electron device.

Background

A Head-up Display (HUD) is a Display device that projects a main pilot instrument attitude indicator and main flight parameters onto a windshield in front of a pilot, and the pilot can know most of the pilot information by projecting the pilot information in a centralized manner without looking over the instrument at a low Head.

The head-up display device reflects an image displayed on an image generation unit (PGU) onto a windshield glass by reflection and amplification of an internal mirror assembly (an aspherical mirror and a plane mirror), and presents a virtual image in front of a driver.

As shown in fig. 1, the head-up display device 3 is disposed below the windshield 2, and includes a housing 31, an image generation unit PGU32, a plane mirror 33, and an aspheric mirror 34 are disposed in the housing 31, and an image displayed on the image generation unit 32 is projected onto the windshield 2 through a cover plate 37 by reflection of the plane mirror 33 and the aspheric mirror 34, and forms a virtual image in front of the driver's eye 1.

In the image generating unit PGU32 of the head-up display device, the image luminance uniformity is poor, the luminance at the middle position is high and also uniform, and the luminance at the corner position is low and uneven, which affects the display quality of the image.

Disclosure of Invention

To the problem that exists among the prior art, the to-be-solved problem of the utility model is to provide a backlight unit, the light guide plate is fresnel structure, constitutes the concave lens towards backlight source, can reduce image brightness loss like this, promotes image brightness uniformity, improves the display quality of image.

The utility model provides a backlight unit, including backlight source and light guide plate, the light guide plate is fresnel structure, constitutes the concave lens towards backlight source.

Furthermore, a scattering structure is arranged on one side of the light guide plate, which is far away from the backlight source.

Further, the scattering structures are dermatoglyphs.

Further, the angle of diffusion of the dermatoglyph is greater than or equal to 10 ° and less than or equal to 30 °.

Further, the focal length of the Fresnel structure ranges from-330 mm to-50 mm.

Further, the fresnel structure on the light guide plate is integrally formed during injection molding, or the fresnel structure and the scattering structure on the light guide plate are integrally formed during injection molding.

The utility model also provides an image generation unit, including above-mentioned backlight unit, display screen and parallel light conversion unit, parallel light conversion unit sets up between backlight source and light guide plate.

The utility model also provides a display device, including above-mentioned backlight unit and display screen.

The utility model also provides an electronic device, including above-mentioned image generation unit, perhaps including above-mentioned display device.

Compared with the prior art, the utility model provides a backlight unit, image generation unit, display device and electron device has following beneficial effect: the light guide plate is of a Fresnel structure and forms a concave lens facing the backlight source, so that the image brightness loss can be reduced, the image brightness uniformity is improved, and the image display quality is improved.

Drawings

Fig. 1 is a schematic diagram of a heads-up display according to an embodiment of the present invention;

fig. 2 is a schematic diagram of an image generation unit of the heads-up display shown in fig. 1.

Detailed Description

As shown in fig. 1, the electronic device of an embodiment of the present invention, such as a head-up display, in other embodiments, the electronic device may also be a meter or an infotainment system.

The head-up display device is arranged below the windshield 2 and comprises a shell 31, an image generation unit PGU32, a plane mirror 33 and an aspherical mirror 34 are arranged in the shell 31, an image displayed on the image generation unit 32 is projected onto the windshield 2 through a cover plate 37 after being reflected by the plane mirror 33 and the aspherical mirror 34, and a virtual image is formed in front of eyes 1 of a driver.

As shown in fig. 2, the image generation unit includes a backlight unit 321 and a display screen 322.

The backlight unit 321 includes a backlight source 3211 and a light guide plate 3212, where the light guide plate 3212 is a fresnel structure, and the fresnel structure forms a concave lens facing the backlight source 3211. The concave lens is also called as a negative ball lens, and the middle of the lens is thin, the edge of the lens is thick, the lens is concave, and the lens has a dispersing effect on light and diffuses the light emitted by the backlight light source 3211.

In this embodiment, the light guide plate 3212 is a plano-concave lens, i.e., the side facing away from the backlight source 3211 is a smooth surface (a plane, rather than a convex surface or a concave surface).

The Fresnel structure is composed of a series of saw-tooth grooves, the angle between each groove and the adjacent groove is different, concentric circles or multiple groups of concentric circle arrays from small to large are recorded, and the texture of the Fresnel structure is designed according to the requirements of light interference and interference, relative sensitivity and receiving angle.

The focal length of the fresnel structure is in the range of-330 mm, -50mm, in this embodiment the focal length of the fresnel structure is-60 mm.

Fresnel structures are mostly injection molded from polyolefin materials, and are also made of glass. In this embodiment, the fresnel structure on the light guide plate 3212 is integrally formed during injection molding.

When the light guide plate 3212 does not adopt a fresnel structure, the uniformity difference of the images viewed at different positions of the HUD view box is significant, and the brightness uniformity of the image at the intermediate position is the best, and the brightness is high, but the brightness uniformity of the image at the corner position of the HUD view box is poor, and the brightness is low.

When the light guide plate 3212 has a fresnel structure, the difference in the uniformity of the image brightness seen at different positions of the HUD view box is not significant.

The fresnel structure forms a concave lens facing the backlight light source 3211, which can increase the diffusion angle of light propagation, reduce the loss of image brightness, improve the uniformity of image brightness, and improve the display quality of images.

A scattering structure is disposed on a side of the light guide plate 3212 facing away from the backlight source 3211 to further increase a diffusion angle of light propagation.

In this embodiment, the scattering structure is a dermatoglyph, and the diffusion angle of the dermatoglyph is greater than or equal to 10 ° and less than or equal to 30 °, and the larger the angle, the stronger the diffusion effect. Similar to the fresnel structure on the light guide plate 3212, the scattering structure is also integrally formed during injection molding.

The backlight unit 321 further includes a parallel light converting unit 3213 disposed between the backlight light source 3211 and the light guide plate 3212. The light emitted from the point light source 3214 is converted into approximately parallel light to increase the light energy utilization rate. If it is stray light rather than parallel light, the loss of light energy is large. In this embodiment, the parallel light conversion unit is, for example, a honeycomb reflector.

The utility model discloses a display device of an embodiment, including backlight unit and display screen, backlight unit includes backlight source and light guide plate, and the light guide plate is fresnel structure, and fresnel structure constitutes the concave lens towards backlight source.

The Fresnel structure forms a concave lens facing the backlight source, so that the diffusion angle of light propagation can be increased, the image brightness loss is reduced, the image brightness uniformity is improved, and the display quality of an image is improved.

Although the present invention has been described with reference to the preferred embodiments, the present invention is not limited thereto. Various changes and modifications can be made by one skilled in the art without departing from the spirit and scope of the invention, and the scope of the invention is to be determined by the appended claims.

Claims

1. A backlight unit is characterized in that the backlight unit comprises a backlight light source and a light guide plate, wherein the light guide plate is of a Fresnel structure and forms a concave lens facing the backlight light source.

2. The backlight unit according to claim 1, wherein a side of the light guide plate facing away from the backlight light source is provided with a scattering structure.

3. The backlight unit of claim 2, wherein the scattering structures are dermatoglyphs.

4. The backlight unit according to claim 3, wherein a diffusion angle of the dermatoglyph is greater than or equal to 10 ° and less than or equal to 30 °.

5. A backlight unit as claimed in any one of claims 1 to 4, characterized in that the focal length of the Fresnel structure is in the range of [ -330mm, -50mm ].

6. The backlight unit according to any one of claims 1 to 4, wherein the Fresnel structure on the light guide plate is integrally formed at the time of injection molding, or the Fresnel structure on the light guide plate and the scattering structure are integrally formed at the time of injection molding.

7. An image generation unit, characterized in that the image generation unit comprises a backlight unit according to any one of claims 1 to 6, a display screen and a parallel light conversion unit, the parallel light conversion unit being arranged between the backlight light source and the light guide plate.

8. A display device, characterized in that the display device comprises a backlight unit as claimed in any one of claims 1 to 6 and a display screen.

9. An electronic device, characterized in that the electronic device comprises the image generation unit of claim 7 or the electronic device comprises the display device of claim 8.