Backlight module, display module and display device

Patent metadata

Field	Value
Publication number	US-12197072-B2
Application number	US-202318139631-A
Country	US
Kind code	B2
Filing date	Apr 26, 2023
Priority date	Jan 16, 2023
Publication date	Jan 14, 2025
Grant date	Jan 14, 2025

Abstract

A backlight module, a display module, and a display device are provided. The backlight module includes a light-emitting area including a first light-emitting area and a second light-emitting area. The second light-emitting area at least partially surrounds the first light-emitting area. The backlight module also includes a light-emitting structure including a plurality of light-emitting elements distributed in the light-emitting area, and a diffusion plate located on a side of a light exiting surface of the light-emitting structure and at least partially located in the light-emitting area. The backlight module also includes a reflection structure located on a surface of the diffusion plate facing the light-emitting structure. The reflection structure overlaps with the first light-emitting area.

First claim

What is claimed is:

1. A backlight module, comprising:
a light-emitting area, including a first light-emitting area and a second light-emitting area, wherein the second light-emitting area at least partially surrounds the first light-emitting area, the first light-emitting area has a first display uniformity, and the second light-emitting area has a second display uniformity different from the first display uniformity;
a light-emitting structure, including a plurality of light-emitting elements distributed in the light-emitting area;
a diffusion plate, located on a side of a light exiting surface of the light-emitting structure, and at least partially located in the light-emitting area; and
a reflection structure, located on a surface of the diffusion plate facing the light-emitting structure, wherein the reflection structure overlaps with the first light-emitting area, and is structured to reflect partial light emitted from the first light-emitting area to the second light-emitting area such as to reduce a difference between the first display uniformity and the second display uniformity.

2. The backlight module according to claim 1 , wherein:
the reflection structure includes at least one first reflection layer;
along a direction perpendicular to a plane where the light-emitting structure is located, the first reflection layer includes a first dielectric layer and a second dielectric layer arranged in a stacked way, and the first dielectric layer is located on a side of the second dielectric layer facing the light-emitting structure;
a refractive index of the first dielectric layer is al, and a refractive index of the second dielectric layer is α2, with α1>α2; and
along the direction perpendicular to the plane where the light-emitting structure is located, a thickness of the first dielectric layer is d1, and a thickness of the second dielectric layer is d2, with λ=2× (n1×d1+n2×d2), wherein A is a wavelength of light emitted by the light-emitting elements to the first reflection layer, n1≥1, n2≥1, each of n1 and n2 is a positive integer, and each of d1 and d2 is a positive number.

3. The backlight module according to claim 2 , wherein:
along the direction perpendicular to the plane where the light-emitting structure is located, the reflection structure includes at least two first reflection layers arranged in a stacked way.

4. The backlight module according to claim 1 , wherein:
the reflection structure includes at least one second reflection layer; and
the second reflection layer is disposed on a surface of the diffusion plate by printing or coating.

5. The backlight module according to claim 4 , wherein:
along a direction parallel to a plane where the diffusion plate is located, the second reflection layer includes at least one sub-second reflection layer, and in the first light-emitting area, a quantity of the sub-second reflection layer is K1 and a quantity of the light-emitting elements is K2, with K1=K2, and along the direction perpendicular to the plane where the light-emitting structure is located, the sub-second reflection layer at least partially overlap with the light-emitting element correspondingly disposed; or
along a direction parallel to a plane where the diffusion plate is located, the second reflection layer includes at least one sub-second reflection layer, and in the first light-emitting area, a quantity of the sub-second reflection layer is K1 and a quantity of the light-emitting elements is K2, with K1>K2, and along the direction perpendicular to the plane where the light-emitting structure is located, at least part of the sub-second reflection layers have an overlapping area with at least part of the light-emitting elements; or
along a direction parallel to a plane where the diffusion plate is located, the second reflection layer includes at least one sub-second reflection layer, and the first light-emitting area includes a first sub-area and a second sub-area and the second sub-area surrounds the first sub-area, and an arrangement density of the sub-second reflection layer in the first sub-area is ρ1 and an arrangement density of the sub-second reflection layer in the second sub-area is ρ2, with ρ1>ρ2; or
along a direction parallel to a plane where the diffusion plate is located, the second reflection layer includes at least one sub-second reflection layer, and the first light-emitting area includes a first sub-area and a second sub-area and the second sub-area surrounds the first sub-area, and along a direction from the first sub-area to the second sub-area, an arrangement density of the sub-second reflection layer decreases.

6. The backlight module according to claim 5 , wherein:
along the direction perpendicular to the plane where the light-emitting structure is located, the sub-second reflection layer covers the light-emitting element.

7. The backlight module according to claim 1 , wherein:
the reflection structure includes a plurality of light-reflective portions and a plurality of light-transparent portions arranged alternately along a plane parallel to the diffusion plate.

8. The backlight module according to claim 1 , further comprising:
a non-light-emitting area, wherein the non-light-emitting area at least partially surrounds the light-emitting area; and
a reflective sheet, located in the non-light-emitting area and disposed around the light-emitting area,
wherein:
the light-emitting structure further comprises a substrate, and the light-emitting elements are disposed on a side of the substrate facing the diffusion plate; and
along a direction perpendicular to a plane where the substrate is located, a height of the reflective sheet is H1, and a height between a surface of the substrate away from the diffusion plate and a surface of the diffusion plate away from the substrate is H2, with H1≥H2.

9. The backlight module according to claim 1 , further comprising a light guide, wherein:
the light-emitting structure further comprises a substrate, and the light-emitting elements are disposed on a side of the substrate facing the diffusion plate; and
the light guide is disposed in the second light-emitting area, and between the substrate and the diffusion plate.

10. The backlight module according to claim 9 , wherein:
the light guide includes at least one spherical surface, and the spherical surface is formed by a surface of the light guide close to the substrate being recessed toward the diffusion plate; and
along a direction perpendicular to a plane where the substrate is located, one of the spherical surfaces overlaps with at least one of the light-emitting elements, or along the direction perpendicular to the plane where the substrate is located, one of the spherical surfaces covers at least one of the light-emitting elements.

11. The backlight module according to claim 10 , wherein:
the light guide further includes mesh points located on a surface of the light guide facing the substrate;
the second light-emitting area includes a third sub-area and a fourth sub-area, and the fourth sub-area surrounds the third sub-area; and
an arrangement density of the mesh points in the third sub-area is ρ3, and an arrangement density of the mesh points in the fourth sub-area is ρ4, with ρ3≤ρ4.

12. The backlight module according to claim 9 , wherein:
the light-emitting structure further comprises a reflection layer, and the reflection layer is disposed on the surface of the substrate facing the diffusion plate; and
along a direction perpendicular to a plane where the substrate is located, the reflection layer and the light-emitting elements do not overlap.

13. The backlight module according to claim

Assignees

• Shanghai Tianma Micro Elect Co

Inventors

• Ji Shengchao
• Yang Xiao
• Zhou Kexiong

Classifications

• G02F1/133605 Primary

  including specially adapted reflectors · CPC title

• G02F1/133603

  with LEDs · CPC title

• G02F1/133607

  the light controlling member including light directing or refracting elements, e.g. prisms or lenses · CPC title

• G02F1/133611

  including means for improving the brightness uniformity · CPC title

• G02F1/133606 Primary

  including a specially adapted diffusing, scattering or light controlling members · CPC title