TW202120974A - Backlight module, method for making same, and display device - Google Patents

Abstract

A backlight module, a method for making the backlight module, and a display device using the backlight module are disclosed. The backlight module includes a substrate, a plurality of light emitting elements, an isolation part, and an optical adhesive layer. The backlight module defines a plurality of backlight regions. At least two of the light emitting elements are arranged in each backlight region. The isolation part is configured to separate any adjacent two backlight regions. The optical adhesive layer covers the light emitting elements and fills a gap between adjacent light emitting elements. A refractive index of the isolation part is greater than a refractive index of the optical adhesive layer.

Description

Backlight module, its manufacturing method and display device

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

Due to its non-self-luminous drive structure and the structural limitations of liquid crystal materials, the liquid crystal display panel cannot block all the backlight when it displays a completely black screen, and there is a phenomenon of “light leakage” on the screen, making it The contrast cannot be greatly improved. For this reason, local dimming technology emerged, which divides the multiple light-emitting elements included in the backlight module into several backlight areas for control. The brightness, turn-on and turn-off of the light-emitting elements corresponding to each backlight area can be individually controlled. control.

However, the conventional area dimming technology has the problem that the light of each backlight area interferes with each other.

One aspect of the present invention provides a backlight module, which includes: A substrate, the substrate having a first surface; A plurality of light-emitting elements are arranged on the first surface at intervals, each of the light-emitting elements is independently controlled, the backlight module defines a plurality of backlight areas, and each of the backlight areas is provided with at least two light-emitting elements ； The isolation part is arranged on the first surface to space any two adjacent backlight regions; and The optical adhesive layer is arranged on the first surface, the optical adhesive layer covers the light-emitting elements and fills the gaps between adjacent light-emitting elements, and the optical adhesive layer is used for performing light emission from the light-emitting elements. diffusion; Wherein, the refractive index of the isolation portion is greater than the refractive index of the optical adhesive layer.

The backlight module is provided with an isolation portion between adjacent backlight areas, so that the light beam is reflected and refracted at the isolation portion, which reduces the mutual interference of light between adjacent backlight areas, thereby effectively reducing the gap between each backlight area. Light leakage between.

Another aspect of the present invention provides a manufacturing method of a backlight module, which includes: A substrate and a plurality of light-emitting elements are provided, the substrate has a first surface, the plurality of light-emitting elements are arranged on the first surface at intervals, each of the light-emitting elements is independently controlled, and the backlight module defines a plurality of backlights Area, each of the backlight areas is provided with at least two of the light-emitting elements; An isolating portion and an optical adhesive layer are formed, the isolating portion is arranged on the first surface to space any two adjacent backlight regions, the optical adhesive layer is arranged on the first surface, and the optical adhesive layer Covering the light-emitting element and filling the gap between adjacent light-emitting elements, and the optical adhesive layer is used to diffuse the light emitted by the light-emitting element; Wherein, the refractive index of the isolation portion is greater than the refractive index of the optical adhesive layer.

In the method for manufacturing the backlight module, by forming an isolation part with a refractive index greater than that of the optical adhesive layer between adjacent backlight regions, the light beam is refracted and reflected between the adjacent backlight regions, thereby weakening the adjacent backlight regions. The mutual interference of light between the backlight areas effectively reduces the light leakage between the backlight areas.

Another aspect of the present invention provides a display device, which includes: The backlight module, the backlight module is the above-mentioned backlight module, and is used for emitting backlight; A liquid crystal display panel, arranged on the side of the backlight module emitting the backlight, for receiving the backlight and displaying images; and The control circuit is electrically connected to the backlight module and the liquid crystal display panel, and is used to control the light emission of the backlight module and the screen display of the liquid crystal display panel.

Since the light beam interference between adjacent backlight regions of the backlight module is reduced, the light leakage of the display device using the backlight module is reduced accordingly, and the contrast of the display device using the same can be improved.

Please refer to FIG. 1, which is a schematic block diagram of a display device 100 according to an embodiment of the present 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 to provide backlight to the liquid crystal display panel 10. The liquid crystal display panel 10 is arranged on the side where the backlight module 30 emits the backlight, and is used for receiving the backlight and displaying images. The control circuit 20 is electrically connected to the backlight module 30 and the liquid crystal display panel 10 for controlling the light emission of the backlight module 30 and the screen display of the liquid crystal display panel 10.

Please refer 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 areas 11 arranged in an array.

Please refer to FIG. 3, which is an equivalent circuit diagram 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 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 minimum area defined by the intersection of the scan lines 12 and the data lines 14内的plex pixel unit 16. The plurality of pixel units 16 defined by the intersection of the scan line 12 and the data line 14 form a matrix arranged in multiple rows and multiple columns. Each pixel unit 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 this embodiment, each display area 11 corresponds to a plurality of rows and a plurality of columns of pixel units 16. In other embodiments, each display area 11 may also be a rectangular strip-shaped area extending along the first direction D1, all the display areas 11 are arranged in a column along the second direction D2, and each display area 11 may correspond to one row or more. Line pixel unit 16.

Please refer 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 and the plurality of display areas 11 shown in FIG. 2 have a one-to-one correspondence. The backlight module 30 is a direct type backlight module, and each backlight area 31 is located directly below a corresponding display area 11 and is used to provide backlight to a corresponding display area 11.

The backlight module 30 includes a substrate 32, a plurality of light-emitting elements 34, an isolation portion 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 32a. The plurality of light-emitting elements 34 are arranged on the first surface 32a of the substrate 32 in an array at intervals. At least two light-emitting elements 34 are provided in each backlight area 31. The isolation portion 36 is located on the first surface 32 a to space any two adjacent backlight regions 31. The substrate 32 may be a flexible circuit board, and the light-emitting element 34 may be a light-emitting diode, but it is not limited to the above.

The backlight module 30 may also include an optical film (not shown) on the side of the light-emitting element 34 away from the substrate 32. The light source film can be one or more, and the optical film can include a diffuser, a light guide plate, etc., which can be selected according to actual needs.

The light-emitting elements 34 corresponding to each backlight area 31 and the light-emitting elements 34 corresponding to other backlight areas 31 can be electrically connected to each other independently, so that the light-emitting elements 34 corresponding to each backlight area 31 can be individually controlled to emit light, turn on or off, In this way, the luminous intensity, on or off of each backlight area 31 can be individually controlled.

Please refer to FIG. 5, which is a cross-sectional view of the backlight module 30 shown in FIG. 4 along the line V-V. The optical adhesive layer 38 is located on the first surface 32 a of the substrate 32, and the light-emitting element 34 and the isolation portion 36 are embedded in the optical adhesive layer 38. In the direction perpendicular to the first surface 32 a, the isolation portion 36 is greater than the height of each light-emitting element 34. The optical adhesive layer 38 fills the gap between adjacent light-emitting elements 34 and the gap between the light-emitting element 34 and the isolation portion 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. surface.

The optical adhesive layer 38 is used to diffuse the light emitted by the light-emitting element 34. The refractive index of the isolation portion 36 is greater than the refractive index of the optical adhesive layer 38. The material of the optical glue layer 38 may be an optical glue containing light diffusing particles. The light diffusing particles are, for example, minute particles made of silicon or epoxy resin, so that the optical adhesive layer 38 has a good light diffusing function.

Please refer to FIG. 6, which is a schematic diagram of the light path of the backlight module 30 shown in FIG. 5. Each light-emitting element 34 is electrically connected to the surface of the substrate 32 as a non-light-emitting surface, and the other side surfaces are light-emitting surfaces. The light beam is emitted from the light-emitting element 34 and directly enters the optical adhesive layer 38. After the light beam emerges from the optical adhesive layer 38, it is partially reflected by the isolation portion 36 and partially isolated at the isolation portion 36 between the adjacent backlight regions 31 Section 36 refracts. Wherein, the incident angle of the light beam when it enters the isolating portion 36 from the optical adhesive layer 38 is θ1, and the refraction angle of the light beam after being refracted by the isolating portion 36 is θ2.

According to the law of light refraction, since the refractive index of the spacer 36 is greater than the refractive index of the optical adhesive layer 38, the refraction angle θ2 is smaller than the incident angle θ1. That is, after the light beam is refracted at the isolation portion 36 between the adjacent backlight regions 31, the divergence angle becomes smaller. In addition, part of the light beam is reflected back at the isolation portion 36 between the adjacent backlight areas 31 and does not enter the adjacent backlight area 31. Thereby, by providing the isolation portion 36 between the adjacent backlight areas 31, the light beam is reflected and refracted at the isolation portion 36, which reduces the mutual interference of light between the adjacent backlight areas 31, thereby effectively reducing the The light leakage between the backlight areas 31 improves the contrast of the display.

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

Please refer to FIG. 7, which is a cross-sectional view of a backlight module 40 according to another embodiment of the present invention. The backlight module 40 and the backlight module 30 have basically the same structure. The difference is that in the backlight module 40, the isolation portion 36 is an air gap 35, and the height of the air gap 35 is in the direction perpendicular to the first surface 32a. It is equal to the height of the optical adhesive layer 38. That is, the optical adhesive layer 38 includes a plurality of blocks 382 arranged at intervals, and each block 382 corresponds to a backlight area 31, and adjacent blocks 382 are separated by an air gap 35. The plurality of light-emitting elements 34 included in each backlight area 31 are covered by a block 382.

Please refer to FIG. 8, which is a flowchart of a manufacturing method of a backlight module according to an embodiment of the present invention. The manufacturing method includes the following steps.

Step S1: Provide a substrate 32 and a plurality of light-emitting elements 34.

As shown in Figure 9. The substrate 32 has a first surface 32a. The plurality of light-emitting elements 34 are arranged on the first surface 32a of the substrate 32 in an array at intervals.

Step S2: forming the isolation portion 36 and the optical adhesive layer 38.

In an embodiment, the isolation portion 36 is formed of a light-transmissive organic material, and step S2 includes:

Step S21: A fence 37 is provided, and the fence 37 is arranged between the light-emitting elements 34 to space any two adjacent backlight regions 31.

Please refer to FIG. 10, which is a top view of the fence 37. The fence 37 is defined with a plurality of grids 372, and each grid 372 corresponds to a backlight area 31.

As shown in FIG. 11, after the fence 37 is arranged in the gap between the light-emitting elements 34, any two adjacent backlight regions 31 are spaced apart, and the height of the fence 37 is greater than the height of each light-emitting element 34. It can be understood that in other embodiments, the height of the fence 37 may be less than or equal to the height of each light-emitting element 34 to reduce the material required for the fence 37, save costs, and facilitate subsequent cleaning and reuse.

Step S22: Inject the optical glue 39 into the gap between the light-emitting elements 34 and the gap between the light-emitting element 34 and the fence 37, so that the light-emitting element 34 and the fence 37 are embedded in the optical glue 39.

As shown in FIG. 12, the optical glue 39 completely fills the gap between the light-emitting elements 34 and the gap between the light-emitting element 34 and the fence 37, and the optical glue 39 covers the surface of the light-emitting element 34 away from the substrate 32 without covering the fence 37 Keep away from the surface of the substrate 32. That is, the fence 37 partially exceeds the optical glue 39. After the optical glue 39 is cured, an optical glue layer 38 is formed. In one embodiment, the fence 37 is formed of a light-transmissive organic material, and the fence 37 is the isolation portion 36. Thereby, the backlight module 30 with the isolation portion 36 formed of a light-transmissive organic material is obtained.

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

Step S21': A fence 37 is provided, and the fence 37 is arranged between the light-emitting elements 34 to space any two adjacent backlight regions 31.

Step S21' is basically the same as step S21 described above. In order to facilitate subsequent removal of the fence 37, the height of the fence 37 provided is greater than the height of each light-emitting element 34. In addition, the height of the fence 37 can also be less than or equal to the height of each light-emitting element 34 to reduce the material required for the fence 37, save costs, and facilitate subsequent cleaning and reuse.

Step S22': Inject the optical glue 39 into the gap between the light-emitting elements 34 and the gap between the light-emitting element 34 and the fence 37, so that the light-emitting element 34 and the fence 37 are embedded in the optical glue 39.

Step S22' is the same as the above-mentioned step S22, and will not be repeated here.

Step S23': Remove the fence 37 so that an air gap 35 is formed between the backlight areas 31. Thereby, the backlight module 40 with the isolation portion 36 as the air gap 35 as shown in FIG. 7 is obtained.

The above embodiments are only used to illustrate the technical solutions of the present invention and not to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced. Without departing from the spirit and scope of the technical solution of the present invention.

100: display device 10: LCD panel 11: Display area 12: Scan line 14: Data cable D1: First direction D2: second direction 16: pixel unit 162: Thin Film Transistor 164: liquid crystal capacitor 20: Control circuit 30, 40: Backlight module 31: Backlight area 32: substrate 32a: first surface 34: Light-emitting element 36: Isolation Department 35: Air gap 38: Optical adhesive layer 382: Block 37: Fence 372: Grid 39: Optical glue

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

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

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

4 is a schematic plan view of the 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 the section line V-V.

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

FIG. 7 is a cross-sectional view of a backlight module provided by another embodiment of the invention.

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

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

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

FIG. 12 is a schematic diagram of step S22 of the manufacturing method of the backlight module according to an embodiment of the present invention.

30: Backlight module

31: Backlight area

32: substrate

32a: first surface

34: Light-emitting element

36: Isolation Department

38: Optical adhesive layer

Claims (10)

A backlight module is improved in that it includes: A substrate, the substrate having a first surface; A plurality of light-emitting elements are arranged on the first surface at intervals, each of the light-emitting elements is independently controlled, the backlight module defines a plurality of backlight areas, and each of the backlight areas is provided with at least two light-emitting elements ； An isolation part is arranged on the first surface to space any two adjacent backlight regions; and The optical adhesive layer is arranged on the first surface, the optical adhesive layer covers the light-emitting elements and fills the gaps between adjacent light-emitting elements, and the optical adhesive layer is used for performing light emission from the light-emitting elements. diffusion; Wherein, the refractive index of the isolation portion is greater than the refractive index of the optical adhesive layer. The backlight module according to claim 1, wherein the isolation portion is formed of a light-transmissive organic material. The backlight module according to claim 1, wherein the isolation portion is an air gap. The backlight module according to claim 3, wherein, in a direction perpendicular to the first surface, the height of the isolation portion is equal to the height of the optical adhesive layer. A method for manufacturing a backlight module includes: A substrate and a plurality of light-emitting elements are provided, the substrate has a first surface, the plurality of light-emitting elements are arranged on the first surface at intervals, each of the light-emitting elements is independently controlled, and the backlight module defines a plurality of backlights Area, each of the backlight areas is provided with at least two of the light-emitting elements; An isolating portion and an optical adhesive layer are formed, the isolating portion is arranged on the first surface to space any two adjacent backlight regions, the optical adhesive layer is arranged on the first surface, and the optical adhesive layer Covering the light-emitting element and filling the gap between adjacent light-emitting elements, and the optical adhesive layer is used to diffuse the light emitted by the light-emitting element; Wherein, the refractive index of the isolation portion is greater than the refractive index of the optical adhesive layer. The manufacturing method of the backlight module according to claim 5, wherein the step of forming the isolation portion and the optical adhesive layer includes: Providing a fence, which is arranged between the light-emitting elements to space any two adjacent backlight regions; and An optical glue is injected into the gap between the light-emitting elements and the gap between the light-emitting element and the fence. The manufacturing method of the backlight module according to claim 6, wherein the isolation portion is an air gap, and the step of forming the isolation portion and the optical adhesive layer further includes removing the fence. The manufacturing method of the backlight module according to claim 6, wherein the fence is formed of a light-transmissive organic material, and the fence is not removed in the step of forming the isolation portion and the optical adhesive layer, The fence is the isolation part. A display device, including: A backlight module, the backlight module being the backlight module according to any one of claims 1 to 4, which is used to emit backlight; A liquid crystal display panel, arranged on the side of the backlight module emitting the backlight, for receiving the backlight and displaying images; and The control circuit is electrically connected to the backlight module and the liquid crystal display panel, and is used to control the light emission of the backlight module and the screen display of the liquid crystal display panel. The display device according to claim 9, wherein the liquid crystal display panel includes a plurality of display areas, the plurality of backlight areas and the plurality of display areas have a one-to-one correspondence, and each of the backlight areas is used to display a corresponding one The display area provides backlighting.

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