CN110806659A

CN110806659A - Backlight module, manufacturing method thereof and display device

Info

Publication number: CN110806659A
Application number: CN201911147192.8A
Authority: CN
Inventors: 张建文; 黄达人
Original assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Current assignee: Interface Optoelectronics Shenzhen Co Ltd; Interface Technology Chengdu Co Ltd; General Interface Solution Ltd
Priority date: 2019-11-21
Filing date: 2019-11-21
Publication date: 2020-02-18
Also published as: TWI724658B; TW202120974A

Abstract

The invention provides a backlight module, a manufacturing method of the backlight module and a display device using the backlight module. The backlight module comprises a substrate, a plurality of light-emitting elements, an isolation part and an optical adhesive layer. The backlight module is defined with a plurality of backlight areas. At least two light-emitting elements are arranged in each backlight area. The isolation part is used for separating any two adjacent backlight areas. The optical adhesive layer covers the light emitting elements and fills gaps between the adjacent light emitting elements. The refractive index of the isolation part is larger than that of the optical adhesive layer.

Description

Backlight module, manufacturing method thereof and display device

Technical Field

The invention relates to the technical field of display, in particular to a backlight module, a manufacturing method thereof and a display device using the backlight module.

Background

Due to the non-self-luminous driving structure and the structural limitation of the liquid crystal material, when the liquid crystal display panel displays a completely black picture, liquid crystal molecules cannot shield all backlight, so that the phenomenon of screen light leakage exists, and the contrast ratio of the liquid crystal display panel cannot be greatly improved. Therefore, Local Dimming (Local Dimming) technology has been developed, which divides a plurality of light emitting elements included in a backlight module into a plurality of backlight areas for control, and the brightness, the on-state and the off-state of the light emitting element corresponding to each backlight area can be independently controlled.

However, the current local dimming technology has a problem that light rays in each backlight area interfere with each other.

Disclosure of Invention

One aspect of the present invention provides a backlight module, which includes:

a substrate having a first surface;

the backlight module is provided with a plurality of backlight areas, and at least two light-emitting elements are arranged in each backlight area;

the isolation part is arranged on the first surface and used for separating any two adjacent backlight areas; and

the optical adhesive layer is arranged on the first surface, covers the light-emitting elements and fills gaps between the adjacent light-emitting elements, and is used for diffusing light rays emitted by the light-emitting elements;

wherein the refractive index of the isolation part is greater than that of the optical adhesive layer.

The backlight module is provided with the isolation parts between the adjacent backlight areas, so that light beams are reflected and refracted at the isolation parts, the mutual interference of light rays between the adjacent backlight areas is weakened, and the light leakage between the backlight areas is effectively reduced.

Another aspect of the present invention provides a method for manufacturing a backlight module, including:

providing a substrate and a plurality of light-emitting elements, wherein the substrate has a first surface, the plurality of light-emitting elements are arranged on the first surface at intervals, each light-emitting element is controlled independently, the backlight module defines a plurality of backlight areas, and at least two light-emitting elements are arranged in each backlight area;

forming an isolation part and an optical adhesive layer, wherein the isolation part is arranged on the first surface to separate any two adjacent backlight areas, the optical adhesive layer is arranged on the first surface, the optical adhesive layer covers the light-emitting elements and fills gaps between the adjacent light-emitting elements, and the optical adhesive layer is used for diffusing light emitted by the light-emitting elements;

According to the manufacturing method of the backlight module, the isolation parts with the refractive indexes larger than that of the optical adhesive layers are formed between the adjacent backlight areas, so that light beams are refracted and reflected between the adjacent backlight areas, the mutual interference of light rays between the adjacent backlight areas is further weakened, and the light leakage between the backlight areas is effectively reduced.

Still another aspect of the present invention provides a display device, including:

the backlight module is used for emitting backlight;

the liquid crystal display panel is arranged on one side of the backlight module, which is used for emitting backlight, and is used for receiving the backlight and displaying pictures; and

and the control circuit is electrically connected with the backlight module and the liquid crystal display panel and is used for controlling the light emission of the backlight module and the picture display of the liquid crystal display panel.

The light beam interference between the adjacent backlight areas of the backlight module is weakened, so that the light leakage phenomenon of the display device using the backlight module is correspondingly reduced, and the contrast of the display device using the backlight module can be improved.

Drawings

Fig. 1 is a schematic block diagram of a display device according to an embodiment of the invention.

Fig. 2 is a schematic plan view of a liquid crystal display panel of the display device shown in fig. 1.

Fig. 3 is an equivalent circuit diagram of a liquid crystal display panel of the display device shown in fig. 1.

Fig. 4 is a schematic plan view of a backlight module of the display device shown in fig. 1.

FIG. 5 is a cross-sectional view of the backlight module shown in FIG. 4 taken along a section line V-V.

Fig. 6 is a schematic light path diagram of the backlight module shown in fig. 5.

Fig. 7 is a cross-sectional view of a backlight module according to another embodiment of the invention.

Fig. 8 is a flowchart of a method for manufacturing a backlight module according to an embodiment of the invention.

Fig. 9 is a schematic diagram of step S1 of the method for manufacturing a backlight module according to the embodiment of the invention.

Fig. 10 and 11 are schematic diagrams of step S21 of a method for manufacturing a backlight module according to an embodiment of the invention.

Fig. 12 is a schematic view of step S22 of the method for manufacturing a backlight module according to an embodiment of the invention.

Description of the main elements

Display device 100

Liquid crystal display panel 10

Display area 11

Scanning line 12

Data line 14

First direction D1

Second direction D2

Pixel unit 16

Thin film transistor 162

Liquid crystal capacitor 164

Control circuit 20

Backlight module

30, 40

Backlight area 31

Substrate 32

First surface 32a

Light emitting element 34

Partition 36

Air gap 35

Optical adhesive layer 38

Block 382

Fence 37

Lattice 372

Optical cement 39

The following detailed description will further illustrate the invention in conjunction with the above-described figures.

Detailed Description

Referring to fig. 1, fig. 1 is a schematic block diagram of a display device 100 according to an embodiment of the invention. The display device 100 includes a liquid crystal display panel 10, a backlight module 30 and a control circuit 20. The backlight module 30 is used for providing backlight to the liquid crystal display panel 10. The liquid crystal display panel 10 is disposed on a side of the backlight module 30 emitting backlight, and is used for receiving the backlight and displaying a picture. The control circuit 20 is electrically connected to the backlight module 30 and the liquid crystal display panel 10, and is used for controlling the light emission of the backlight module 30 and the image display of the liquid crystal display panel 10.

Referring to fig. 2, fig. 2 is a schematic plan view of the liquid crystal display panel 10 of the display device 100 shown in fig. 1. The liquid crystal display panel 10 includes a plurality of display regions 11 arranged in an array.

Referring to fig. 3, fig. 3 is an equivalent circuit diagram of the lcd panel 10 of the display device 100 shown in fig. 1. The liquid crystal display panel 10 includes a plurality of scan lines 12 extending in a first direction D1, a plurality of data lines 14 extending in a second direction D2 crossing the first direction D1, and a plurality of pixel cells 16 located in a minimum region defined by the crossing of the scan lines 12 and the data lines 14. A plurality of pixel units 16 defined by the intersections of the scan lines 12 and the data lines 14 are arranged in a matrix of rows and columns. Each pixel cell 16 includes a thin film transistor 162 and a liquid crystal capacitor 164. The gate of the thin film transistor 162 is electrically connected to a scan line 12, the source of the thin film transistor 162 is electrically connected to a data line 14, and the drain of the thin film transistor 162 is electrically connected to the liquid crystal capacitor 164.

In the present embodiment, each display region 11 corresponds to a plurality of rows and columns of pixel units 16. In other embodiments, each display region 11 may also be a rectangular stripe extending along the first direction D1, all the display regions 11 are arranged in a column along the second direction D2, and each display region 11 may correspond to one or more rows of pixel units 16.

Referring to fig. 4, fig. 4 is a schematic plan view of the backlight module 30 of the display device 100 shown in fig. 1. The backlight module 30 defines a plurality of backlight areas 31. The plurality of backlight areas 31 correspond to the plurality of display areas 11 shown in fig. 2 one to one. The backlight module 30 is a direct-type backlight module, and each of the backlight regions 31 is located right below a corresponding one of the display regions 11 and configured to provide backlight to the corresponding one of the display regions 11.

The backlight module 30 includes a substrate 32, a plurality of light emitting elements 34, a spacer 36, and an optical adhesive layer 38 (the optical adhesive layer 38 is omitted in fig. 4, and is marked in fig. 5). The substrate 32 has a first surface 32 a. A plurality of light emitting elements 34 are arranged in an array spaced apart on the first surface 32a of the substrate 32. At least two light emitting elements 34 are disposed in each backlight area 31. The partition 36 is located on the first surface 32a to space any adjacent two backlight areas 31. The substrate 32 may be a flexible circuit board, and the light emitting element 34 may be a light emitting diode, but not limited thereto.

The backlight assembly 30 may further include an optical film (not shown) on a side of the light emitting elements 34 away from the substrate 32. The light source film can be one or more, and the optical film can comprise a diffusion sheet, a light guide plate and the like, and can be selected according to actual needs.

The light emitting element 34 corresponding to each backlight area 31 and the light emitting elements 34 corresponding to the other backlight areas 31 can be electrically connected to be independent from each other, so that the light emitting element 34 corresponding to each backlight area 31 can be controlled to emit light independently, turned on or turned off, and the light emitting brightness, turned on or turned off of each backlight area 31 can be controlled independently.

Referring to FIG. 5, FIG. 5 is a cross-sectional view of the backlight module 30 shown in FIG. 4 along the line V-V. An optical glue layer 38 is located on the first surface 32a of the substrate 32, and the light emitting elements 34 and the spacers 36 are embedded in the optical glue layer 38. The partition 36 is larger than the height of each light emitting element 34 in the direction perpendicular to the first surface 32 a. The optical glue layer 38 fills the gaps between the adjacent light emitting elements 34 and the gaps between the light emitting elements 34 and the isolation portions 36, and completely covers the surface of each light emitting element 34 away from the substrate 32 and the surface of the isolation portion 36 away from the substrate 32.

The optical adhesive layer 38 is used for diffusing the light emitted from the light emitting element 34. The refractive index of the spacer 36 is greater than the refractive index of the optical glue layer 38. The material of the optical glue layer 38 may be an optical glue containing light diffusing particles. The light diffusion particles are, for example, fine particles made of a material containing silicon or epoxy resin, so that the optical adhesive layer 38 has a good light diffusion function.

Referring to fig. 6, fig. 6 is a schematic light path diagram of the backlight module 30 shown in fig. 5. Each light emitting element 34 is electrically connected to the substrate 32, and has a non-light emitting surface and light emitting surfaces on the other sides. Light beams emitted from the light emitting elements 34 directly enter the optical adhesive layer 38, and after the light beams are emitted from the optical adhesive layer 38, the light beams are partially reflected by the partitions 36 and partially refracted by the partitions 36 at the partitions 36 between the adjacent backlight regions 31. The incident angle of the light beam entering the spacer 36 from the optical glue layer 38 is θ 1, and the refraction angle of the light beam refracted by the spacer 36 is θ 2.

As can be seen from the light refraction law, since the refractive index of the spacer 36 is larger than that of the optical cement layer 38, the refraction angle θ 2 is smaller than the incident angle θ 1. That is, the light beams are refracted at the partitions 36 between the adjacent backlight areas 31, and the divergence angle is reduced. In addition, since a part of the light beam is reflected at the partitions 36 between the adjacent backlight areas 31 without entering the adjacent backlight areas 31. Thus, by providing the isolation portion 36 between the adjacent backlight regions 31, the light beams are reflected and refracted at the isolation portion 36, so that the mutual interference of the light beams between the adjacent backlight regions 31 is reduced, the light leakage between the backlight regions 31 is effectively reduced, and the display contrast is improved.

In one embodiment, the isolation portion 36 is formed of a transparent organic material, such as resin or acrylic. The height of the partition 36 may be less than, equal to, or greater than the height of each light emitting element 34.

Referring to fig. 7, fig. 7 is a cross-sectional view of a backlight module 40 according to another embodiment of the invention. The backlight module 40 has a structure substantially the same as that of the backlight module 30, and the differences are: in the backlight module 40, the spacer 36 is an air gap 35, and the height of the air gap 35 is equal to the height of the optical adhesive layer 38 along the direction perpendicular to the first surface 32 a. That is, the optical adhesive layer 38 includes a plurality of blocks 382 arranged at intervals, each block 382 corresponds to one backlight area 31, and adjacent blocks 382 are spaced by the air gap 35. Each of the backlight regions 31 includes a plurality of light emitting elements 34 covered by a block 382.

Referring to fig. 8, fig. 8 is a flowchart illustrating a method for manufacturing a backlight module according to an embodiment of the invention. The manufacturing method comprises the following steps.

Step S1: a substrate 32 and a plurality of light emitting elements 34 are provided.

As shown in fig. 9. The substrate 32 has a first surface 32 a. A plurality of light emitting elements 34 are arranged in an array spaced apart on the first surface 32a of the substrate 32.

Step S2: spacers 36 and an optical glue layer 38 are formed.

In one embodiment, the isolation portion 36 is formed of a transparent organic material, and the step S2 includes:

step S21: a barrier 37 is provided, and the barrier 37 is disposed between the light emitting elements 34 to space any adjacent two backlight areas 31.

Referring to fig. 10, fig. 10 is a top view of the fence 37. The barrier 37 defines a plurality of cells 372, and each cell 372 corresponds to one backlight area 31.

As shown in fig. 11, after the barriers 37 are disposed in the gaps between the light emitting elements 34, any two adjacent backlight areas 31 are spaced apart, and the height of the barrier 37 is greater than the height of each light emitting element 34. It is understood that in other embodiments, the height of the barriers 37 may be less than or equal to the height of each light emitting element 34 to reduce the material required for the barriers 37, save cost, and facilitate subsequent cleaning and recycling.

Step S22: optical cement 39 is injected into the gaps between the light emitting elements 34 and the barriers 37, so that the light emitting elements 34 and the barriers 37 are embedded in the optical cement 39.

As shown in fig. 12, the optical paste 39 completely fills the gaps between the light emitting elements 34, and the gaps between the light emitting elements 34 and the fences 37, and the optical paste 39 covers the surfaces of the light emitting elements 34 away from the substrate 32, and does not cover the surfaces of the fences 37 away from the substrate 32. I.e. the fence 37 partly extends beyond the optical glue 39. Optical adhesive 39 cures to form optical adhesive layer 38. In one embodiment, the barrier 37 is formed of a light-transmissive organic material, and the barrier 37 is the isolation portion 36. Thus, the backlight module 30 having the spacer 36 formed of a light-transmitting organic material is obtained.

In another embodiment, the isolation portion 36 is an air gap 35, and step S2 includes:

step S21': a barrier 37 is provided, and the barrier 37 is disposed between the light emitting elements 34 to space any adjacent two backlight areas 31.

Step S21' is substantially the same as step S21 described above. Wherein, in order to facilitate the removal of the subsequent fence 37, the height of the fence 37 is provided to be greater than the height of each light emitting element 34. In addition, the height of the fence 37 can be less than or equal to the height of each light emitting element 34, so as to reduce the material required by the fence 37, save the cost and facilitate the subsequent cleaning and recycling.

Step S22': optical cement 39 is injected into the gaps between the light emitting elements 34 and the barriers 37, so that the light emitting elements 34 and the barriers 37 are embedded in the optical cement 39.

Step S22' is the same as step S22, and will not be described herein.

Step S23': the barriers 37 are removed so that air gaps 35 are formed between the backlight areas 31. Thus, the backlight module 40 having the air gap 35 as the spacer 36 as shown in fig. 7 is obtained.

Although the present invention has been described in detail with reference to the preferred embodiments, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof without departing from the spirit and scope of the present invention.

Claims

1. A backlight module, comprising:

a substrate having a first surface;

2. The backlight module according to claim 1, wherein the partition is formed of a light-transmissive organic material.

3. The backlight module of claim 1, wherein the spacer is an air gap.

4. The backlight module as claimed in claim 3, wherein the height of the spacers is equal to the height of the optical adhesive layer in a direction perpendicular to the first surface.

5. A method for manufacturing a backlight module comprises the following steps:

6. The method as claimed in claim 5, wherein the step of forming the spacers and the optical adhesive layer comprises:

providing a fence, arranging the fence between the light-emitting elements to separate any two adjacent backlight areas; and

and injecting optical cement into the gaps among the light-emitting elements and the gaps between the light-emitting elements and the barriers.

7. The method as claimed in claim 6, wherein the spacers are air gaps, and the step of forming the spacers and the optical adhesive layer further comprises removing the barriers.

8. The method as claimed in claim 6, wherein the barrier is formed of a light-transmissive organic material, and the barrier and the optical adhesive layer are formed without removing the barrier, the barrier being the barrier.

9. A display device, comprising:

a backlight module as claimed in any one of claims 1 to 4 for emitting backlight;

10. The display device according to claim 9, wherein the liquid crystal display panel includes a plurality of display regions, the plurality of backlight regions and the plurality of display regions are in one-to-one correspondence, each of the backlight regions being configured to provide backlight to a corresponding one of the display regions.