JP-2026514310-A - Backlight module and display device

Abstract

The backlight module comprises a light guide plate having a light incident surface, a light-emitting mechanism located on the side of the light incident surface, a first prism sheet located above the light guide plate with a haze value of non-zero and provided with a plurality of asymmetrical first prism structures, and a second prism sheet located above the first prism sheet and provided with a plurality of asymmetrical second prism structures. The present invention further provides a display device comprising the backlight module. [Selection Diagram] Figure 1

Inventors

• チェン，チア‐フェイ
• ウェン，チン‐ティン
• チャン，チア‐イン

Assignees

• ラディアント（クワンチョウ）オプト‐エレクトロニクス カンパニー リミテッド
• ラディアント オプト－エレクトロニクス コーポレーション

Dates

Publication Date

20260508

Application Date

20240607

Priority Date

20230608

Claims (20)

1. It is a backlight module, It comprises a light guide plate, a light-emitting mechanism, a first prism sheet, and a second prism sheet. The light guide plate has a light incident surface and a light emission surface that are connected to each other. The light-emitting mechanism is located on the side of the light incident surface of the light guide plate, The first prism sheet has a non-zero haze value, is located above the light-emitting surface of the light guide plate, and has a first light-incident surface and a first light-emitting surface that are positioned opposite each other, the first light-incident surface is directed toward the light-emitting surface of the light guide plate, and the first light-emitting surface is provided with a plurality of first prism structures, the first prism structures having an asymmetric structure. The second prism sheet is located above the first prism sheet and has a second light incident surface and a second light emission surface that are positioned opposite each other, the second light incident surface facing the first light emission surface of the first prism sheet, and the second light emission surface is provided with a plurality of second prism structures, the second prism structures having an asymmetric structure. (Backlight module.)
2. The haze value of the first prism sheet is in the range of 10% to 30%, including the endpoint value, as described in claim 1 of the backlight module.
3. The haze value of the second prism sheet is 20% or less, including the endpoint value, as described in claim 2 of the backlight module.
4. The backlight module according to claim 2, wherein the haze value of the second prism sheet is zero.
5. The backlight module according to claim 1, wherein the first prism structure is a strip structure formed by a first side surface and a second side surface, the second prism structure is a strip structure formed by a third side surface and a fourth side surface, the first side surface and the third side surface are each closer to the light incident surface than the second side surface and the fourth side surface, the first side surface and the first light emission surface have a first binding angle, the second side surface and the first light emission surface have a second binding angle, the first binding angle is larger than the second binding angle, the third side surface and the second light emission surface have a third binding angle, the fourth side surface and the second light emission surface have a fourth binding angle, the third binding angle is larger than the fourth binding angle.
6. The backlight module according to claim 1, further comprising a diffusion sheet located above the second prism structure.
7. The backlight module according to claim 1, wherein the light guide plate further has a bottom surface facing the light emitting surface, and the reflective sheet is located on the side of the bottom surface of the light guide plate.
8. A display device, A backlight module according to any one of claims 1 to 7, A display device comprising a display panel located above the backlight module.
9. It is a backlight module, It comprises a light guide plate, a light-emitting mechanism, a first prism sheet, and a second prism sheet. The light guide plate has a light incident surface and a light emission surface that are connected to each other. The light-emitting mechanism is located on the side of the light incident surface of the light guide plate, The first prism sheet has a haze value that is not zero, and is located above the light-emitting surface of the light guide plate and has a first light-incident surface and a first light-emitting surface that are set opposite each other, the first light-incident surface is directed toward the light-emitting surface of the light guide plate, and the first light-emitting surface is provided with a plurality of first prism structures, the first prism structure is asymmetrical and is a strip structure formed by a first side surface and a second side surface, a first vertex angle is formed between the first side surface and the second side surface, within the range of 60 to 90 degrees, including the endpoint value, a first binding angle is formed between the first side surface and the first light-emitting surface, within the range of 50 to 80 degrees, including the endpoint value, and a second binding angle is formed between the second side surface and the first light-emitting surface. The second prism sheet is located above the first prism sheet and has a second light incident surface and a second light emission surface that are set opposite each other, the second light incident surface is directed toward the first light emission surface of the first prism sheet, and the second light emission surface is provided with a plurality of second prism structures, the second prism structures are asymmetric structures and are strip-like structures formed by a third side surface and a fourth side surface, a second vertex angle is formed between the third side surface and the fourth side surface, within the range of 60 to 90 degrees, including the endpoint value, a third binding angle is formed between the third side surface and the second light emission surface, within the range of 50 to 80 degrees, including the endpoint value, and a fourth binding angle is formed between the fourth side surface and the second light emission surface. The first and third sides are each closer to the light incident surface than the second and fourth sides, and the refractive indices of the first and second prism sheets are in the range of 1.5 to 1.7, including the endpoint values. The microstructure has an extension angle between the first extension direction of the first prism structure and the second extension direction of the second prism structure, which is within the range of 0 to 40 degrees, including the endpoint value. The first prism structure has a first spacing, which is in the range of 15 μm to 55 μm and includes endpoint values, and the second prism structure has a second spacing, which is in the range of 15 μm to 55 μm and includes endpoint values, and the first spacing is not equal to the second spacing.
10. The haze value of the first prism sheet is in the range of 10% to 30%, including the endpoint value, as described in claim 9 of the backlight module.
11. The haze value of the second prism sheet is 20% or less, including the endpoint value, as described in claim 9 of the backlight module.
12. The backlight module according to claim 9, wherein the haze value of the second prism sheet is zero.
13. The backlight module according to claim 9, wherein the refractive index of the second prism sheet is greater than or equal to the refractive index of the first prism sheet.
14. The backlight module according to claim 9, wherein the first vertex angle is greater than the second vertex angle.
15. The backlight module according to claim 9, wherein the peak value of the light rays emitted from the backlight module in the first direction is less than 10 degrees.
16. The backlight module according to claim 9, wherein in a first direction, the light rays emitted from the backlight module have a first half-width angle, and in a second direction, the light rays emitted from the backlight module have a second half-width angle, the second direction is perpendicular to the first direction, and the ratio of the second half-width angle to the first half-width angle is in the range of 1.65 to 3.69, including endpoint values.
17. The backlight module according to claim 16, wherein the second half-width angle is in the range of 28 to 59 degrees and includes endpoint values.
18. The backlight module according to claim 9, further comprising an optical film located above the second prism structure.
19. The backlight module according to claim 9, wherein the light guide plate further has a bottom surface facing the light emitting surface, and the reflective sheet is located on the side of the bottom surface of the light guide plate.
20. A display device, A backlight module according to any one of claims 9 to 19, A display device comprising a display panel located above the backlight module.

Description

This invention primarily relates to a backlight module, and more particularly to a backlight module capable of effectively concentrating light rays to improve brightness, and to a display device to which such a backlight module is applied. Conventional backlight modules can produce different light emission characteristics by combining different optical films. For example, they may exhibit a uniform light emission across the entire optical surface, or a concentrated light emission where light rays are focused on specific areas of the optical surface. These backlight modules with different light emission characteristics can be applied to different display devices, such as vehicle displays. For instance, a vehicle display installed in the passenger seat typically needs to avoid directing the light emission towards the driver to ensure driving safety and avoid obstructing the driver. Conventional backlight modules have two prism sheets in the direction of light emission from the light guide plate. By staggering the elongated prism structures of the two prism sheets, the brightness improvement effect of conventional backlight modules can be achieved. However, if the prism structures of both prism sheets are symmetrical, and the angle between the extension directions of the two prism sheets is 90°, conventional backlight modules tend to generate stray light, reducing the overall light emission effect. In light of this, it is necessary to provide a backlight module that solves the above-mentioned problems. The objective of the present invention is to provide a backlight module that can effectively concentrate light rays to improve brightness and further enhance the overall light emission effect. A further object of the present invention is to provide a display device having the above-described backlight module that is suitable for application forms of a high-brightness concentrated light-emitting region. To achieve the above objective, the present invention provides a backlight module comprising a light guide plate, a light-emitting mechanism, a first prism sheet, and a second prism sheet, wherein the light guide plate has a light-incident surface and a light-emitting surface connected to each other, the light-emitting mechanism is located on the side of the light-incident surface of the light guide plate, the first prism sheet has a non-zero haze value, the first prism sheet is located above the light-emitting surface of the light guide plate and has a first light-incident surface and a first light-emitting surface that are installed opposite each other, the first light-incident surface is directed toward the light-emitting surface of the light guide plate, and the first light-emitting surface is provided with a plurality of first prism structures. The first prism structure is an asymmetrical structure and is a strip structure formed by a first side surface and a second side surface, a first vertex angle is formed between the first side surface and the second side surface, within the range of 60 to 90 degrees, including the endpoint value, a first binding angle is formed between the first side surface and the first light-emitting surface, within the range of 50 to 80 degrees, including the endpoint value, a second binding angle is formed between the second side surface and the first light-emitting surface, the second prism sheet is located above the first prism sheet and has a second light-incident surface and a second light-emitting surface that are set opposite each other, the second light-incident surface is the first The prism sheet is directed toward the first light-emitting surface, and the second light-emitting surface is provided with a plurality of second prism structures, the second prism structures are asymmetrical and are strip-shaped structures formed by a third side surface and a fourth side surface, a second vertex angle is formed between the third side surface and the fourth side surface, within the range of 60 to 90 degrees, including the endpoint value, a third binding angle is formed between the third side surface and the second light-emitting surface, within the range of 50 to 80 degrees, including the endpoint value, a fourth binding angle is formed between the fourth side surface and the second light-emitting surface, and the first side surface and the third side surface are each the second Closer to the light incident surface than the side and the fourth side, the refractive indices of the first and second prism sheets are in the range of 1.5 to 1.7, including the endpoint value, and the microstructure has an extension angle between the first extension direction of the first prism structure and the second extension direction of the second prism structure, in the range of 0 to 40 degrees, including the endpoint value. The first prism structure has a first spacing, in the range of 15 μm to 55 μm, including the endpoint value, and the second prism structure has a second spacing, in the range o