CN114035369B

CN114035369B - Backlight module and liquid crystal display

Info

Publication number: CN114035369B
Application number: CN202110797769.0A
Authority: CN
Inventors: 张朋月; 黄嘉桦
Original assignee: Chongqing Kangjia Photoelectric Technology Research Institute Co Ltd
Current assignee: Chongqing Kangjia Optoelectronic Technology Co ltd
Priority date: 2021-07-14
Filing date: 2021-07-14
Publication date: 2022-08-26
Anticipated expiration: 2041-07-14
Also published as: WO2023284641A1; CN114035369A

Abstract

The invention relates to a backlight module and a liquid crystal display, wherein the backlight module comprises: the backlight module comprises a substrate, a backlight lamp, an optical film and a white dam; one side surface of the substrate comprises a plurality of backlight areas, and a plurality of backlight lamps are arranged on the backlight areas; the optical film is laminated on the surface of the substrate provided with the backlight lamp and covers the backlight lamp; a white dam is arranged around each backlight area, and the white dam is raised relative to the surface of the optical film, which faces away from the substrate. The white dam surrounds the backlight area, and thus, the white dam may even out the entire backlight area, which is color converted by its corresponding optical film layer, and so on. That is, the whole backlight module performs uniform color and color conversion by taking the backlight area as a unit, and at this time, the side light of the backlight lamp in the backlight area is emitted to the white dam and then reflected to the substrate by the white dam, so that the halation phenomenon can be prevented.

Description

Backlight module and liquid crystal display

Technical Field

The present invention relates to the field of display, and in particular, to a backlight module and a Liquid Crystal Display (LCD).

Background

In the technical field of display, two display modes of a Cathode Ray Tube (CRT) and an LCD are available, and compared with the CRT, the LCD occupies a small space, has lower power consumption, lower radiation and no flicker, and is not easy to generate visual fatigue. Accordingly, LCDs have become a mainstream trend in the display field.

The LCD itself cannot emit light, and it needs extra light source to emit light, and the extra part is usually called as backlight module, because the LED has the characteristics of low power consumption, low heat generation, high brightness, long service life, etc., the LED chip is generally selected to provide light source for the LCD, so that the LCD works smoothly. Generally, the backlight module is mostly a side-light-entering type backlight module.

The backlight module generally includes a substrate, an LED chip fixed on a surface of one side of the substrate, and an optical film laminated on a surface of the substrate on which the LED chip is disposed. Light emitted by the LED is emitted into the optical film layer from the light incident surface, is reflected out of the light emergent surface of the optical film layer, and then enters the liquid crystal display module.

However, in the current backlight module, a hot spot (hotspot) problem easily occurs, and the hot spot problem is that a bright area of a light column appears in an area where an optical film is close to an LED light source because the divergence angle of the LED light source is limited, so that a poor phenomenon of uneven brightness exists in a light emitting surface of a light incident side of the backlight module.

In order to solve the above problems, a diffusion sheet is generally added, but after the diffusion sheet is added, although the hot spot problem is solved, the halation phenomenon is easily generated.

Disclosure of Invention

In view of the above-mentioned deficiencies of the prior art, the present application provides a backlight module and a liquid crystal display, which aims to solve the problem that after a diffusion sheet is added, the light halo is likely to occur.

The present application provides in a first aspect a backlight module comprising: the backlight module comprises a substrate, a backlight lamp, an optical film and a white dam; one side surface of the substrate comprises a plurality of backlight areas, and a plurality of backlight lamps are arranged on the backlight areas; the optical film is laminated on the surface of the substrate provided with the backlight lamp and covers the backlight lamp; the white dam is arranged around each backlight area, and the white dam is raised relative to the surface, away from the substrate, of the optical film.

The white dam surrounds the backlight area, and the backlight area is provided with a plurality of backlight lamps, so that the white dam can homogenize the whole backlight area, the backlight area is subjected to color conversion by the corresponding optical film layer, and the like. That is, the whole backlight module performs color uniformization and color conversion and the like by taking the backlight area as a unit, and at this time, the side light emitted from the backlight lamp in the backlight area is reflected to the substrate from the white dam after being irradiated to the white dam, so that the halation phenomenon can be prevented.

In some embodiments, any two adjacent backlight regions share a portion of the white dam. Therefore, resources can be saved, and the cost can be reduced.

In some embodiments, the white dam includes a top surface and a bottom surface oppositely disposed in a thickness direction of the backlight module; the top surface faces away from the optical film, and the bottom surface contacts the optical film; in the width direction of the backlight module, the size of the top surface is smaller than that of the bottom surface. Therefore, the white box dam has strong structural stability and is not easy to incline or collapse.

In some embodiments, the cross-sectional shape of the white dam is an isosceles trapezoid or an isosceles triangle; the width direction is perpendicular to the thickness direction of the backlight module and is perpendicular to the extending direction of the white dam. The cross section of the white box dam is designed to be isosceles trapezoid or isosceles triangle, so that the processing is convenient, and the processing cost is reduced; and the structural stability of the white dam can be increased.

In some embodiments, the white dam extends through the optical film along the thickness direction of the backlight module and is fixed to the surface of the substrate on which the backlight is disposed, that is, the white dam has a thicker thickness, can extend through the entire optical film and is higher than the optical film. Therefore, after the side light of the backlight is emitted to the white dam, the side light can be reflected to the upper light-emitting surface by the white dam and then emitted from the upper light-emitting surface. The setting mode can increase the light-emitting intensity, improve the light energy utilization rate and achieve the purpose of saving energy.

In other embodiments, the white dam extends into the optical film along the thickness direction of the backlight module, and the bottom surface of the white dam is flush with the edge of the side light outlet surface of the backlight lamp facing the substrate. Therefore, the white dam can reflect the side light of the backlight lamp to the upper light-emitting surface as much as possible, the thickness of the white dam can be reduced, and resources are saved.

In some embodiments, the material of the white dam includes any one of white dam glue, white photosensitive glue and white paint.

In some embodiments, the white dam is raised relative to a surface of the optical film facing away from the substrate by a dimension greater than or equal to 10 microns. Therefore, the white box dam can play a supporting role and prevent the halation phenomenon.

In some embodiments, the optical film comprises a color conversion layer, a diffusion layer, and a reflective layer sequentially stacked from top to bottom; the diffusion layer faces the white dam and the reflection layer faces the substrate. The reflecting layer can homogenize the intensity of light emitted by the backlight, the diffusion layer can make the color of the light emitted by the backlight more uniform, and the color conversion layer can convert blue light emitted by the blue light backlight into red light or green light, so that the multi-color display requirement of the LCD is met.

In some embodiments, the size of the optical film is greater than or equal to 63 micrometers and less than or equal to 330 micrometers in the thickness direction of the backlight module. Because the thickness of the backlight is 10 to 100 micrometers in general, the thickness of the optical film is set to be 63 to 330 micrometers, so that the optical film can cover the backlight and the thickness of the optical film can be in a reasonable range, thereby reducing the thickness of the backlight module and saving resources.

Based on the same inventive concept, the present application further provides an LCD, including the backlight module of any one of the above first aspects and a plurality of liquid crystal layers, wherein the plurality of liquid crystal layers are all stacked on a light emitting surface of the backlight module; and the orthographic projection area of the frame of the liquid crystal layer on the substrate is superposed with the orthographic projection area of the white dam on the substrate.

After the LCD is applied to the backlight module in the first aspect of the application, under the effect of the white dam, the halation phenomenon is obviously improved.

Drawings

Fig. 1 is a schematic structural diagram of a related art LCD.

Fig. 2 is a schematic diagram of a hot spot phenomenon structure.

Fig. 3 is a schematic diagram of the structure of the halation phenomenon.

Fig. 4 is a schematic structural diagram of a backlight module according to an embodiment of the present application.

Fig. 5 is a schematic structural diagram of a display panel corresponding to the backlight module shown in fig. 1.

Fig. 6 is an enlarged view of fig. 4 at a.

Fig. 7 is a schematic view of a layered structure of the backlight module shown in fig. 6 and 1 along a thickness direction.

Fig. 8 is a cross-sectional view of a backlight module according to another embodiment of the present application, taken along a thickness direction.

Fig. 9 is a cross-sectional view of a backlight module according to another embodiment of the present application, the cross-sectional view being taken along a thickness direction.

Description of reference numerals:

the prior art is as follows: 10-a backlight module, 11-an optical membrane, 12-a diffusion layer, 13-a color conversion layer, 14-a brightening membrane layer, 15-a reflection type polarized light brightening membrane layer, 16-a substrate, 17-a backlight lamp and 20-a display panel;

the invention comprises the following steps: 1000-backlight module, 100-substrate, 110-backlight area, 200-backlight, 300-optical film, 310-color conversion layer, 320-diffusion layer, 330-reflection layer, 400-white dam, 410-top surface, 420-bottom surface, 500-liquid crystal layer, 510-pixel; x-extension direction, Y-width direction, Z-thickness direction.

Detailed Description

To facilitate an understanding of the present application, the present application will now be described more fully with reference to the accompanying drawings. Preferred embodiments of the present application are given in the accompanying drawings. This application may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the description of the present application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

Referring to fig. 1, fig. 1 is a schematic structural diagram of a related art LCD, the LCD includes a display panel 20 and a backlight module 10, and the backlight module 10 includes an optical film 11, a substrate 16, and a backlight 17. The optical film 11 includes a diffusion layer 12, a color conversion layer 13, a brightness enhancement film layer 14 (BEF) and a reflection-type polarization enhancement film (DBEF) layer 15, which are sequentially stacked; the backlight 17 is provided on the substrate 16. The backlight 17 may be a mini-LED or micro-LED chip. In the backlight module 10 of this type, the hot spot problem as shown in fig. 2 is easily generated, that is, the part is bright and the part is dark, and an image with uneven brightness is formed.

And after the diffusion plate is added, although the hot spot problem is solved, the halation phenomenon as shown in fig. 3 is easily occurred. In order to solve the above problems, an embodiment of the present application provides a backlight module 1000.

Referring to fig. 4 to 7, fig. 4 is a schematic structural diagram of a backlight module according to an embodiment of the present application, fig. 5 is a schematic structural diagram of a display panel corresponding to the backlight module shown in fig. 1, fig. 6 is an enlarged view of a portion a of fig. 4, and fig. 7 is a schematic structural diagram of a layered structure of the backlight module shown in fig. 6 and 1 along a thickness direction. The backlight module 1000 provided in this embodiment specifically includes: a substrate 100, a backlight 200, an optical film 300, and a white dam 400.

Wherein, a side surface of the substrate 100 includes a plurality of backlight regions 110, and a plurality of backlight lamps 200 are disposed on the backlight regions 110; the optical film 300 is laminated on the surface of the substrate 100 on which the backlight 200 is provided, and covers the backlight 200. In the embodiments of the present application, a plurality means two or more. The white dam 400 is disposed around each of the backlight regions 110, and the white dam 400 is raised with respect to the surface of the optical film 300 facing away from the substrate 100.

The backlight 200 may be a Cold Cathode Fluorescent Lamp (CCFL), which has advantages of high power and high brightness. The backlight 200 may be an LED, which has advantages of high brightness, low power consumption, long life, and the like. Therefore, those skilled in the art can select CCFL or LED as the backlight 200 according to actual requirements.

In general, in LCD products, a display panel usually has a plurality of liquid crystal layers 500, and a frame is usually provided on the liquid crystal layer 500, the frame is usually black and is not used for displaying images, etc., but is used for laying gate metal traces of a driving device, and a Black Matrix (BM) is required to be arranged in a black frame region for shielding. Correspondingly, the liquid crystal layer 500 is displayed in partitions under BM, each partition having a plurality of pixels 510, each pixel 510 including a red pixel, a green pixel and a blue pixel. Each partition includes several tens to several thousands of pixels 510, such as a 2K display, and if there are 516 partitions, each partition corresponds to 4000 pixels 510. As shown in fig. 5, the BM partitions the display panel into individual sub-pixels, and each individual sub-pixel is repeated with a set of red, green, blue (RGB) as a unit.

It can be understood that when the backlight module 1000 is applied to an LCD, the edge of the backlight area 110 is aligned with the BM, and the BM is used as a barrier layer between the LCD pixels 510 and is opaque, so that the visual effect is not affected. And a plurality of backlight areas 110 on the backlight module 1000 correspond to each partition in the liquid crystal layer 500 one by one, so that the halo phenomenon can be eliminated by partitioning, the cost is low, and the eliminating effect is good.

It is understood that one pixel 510 corresponds to three backlight lamps 200, wherein a red pixel, a green pixel and a blue pixel correspond to one backlight lamp 200, respectively, so that if the LCD is 2K display, the corresponding backlight module needs 516 backlight regions 110, and each backlight region 110 corresponds to 4000 × 3 backlight lamps 200.

In this embodiment, the white dam 400 surrounds the backlight area 110, and therefore, the white dam 400 can homogenize the entire backlight area 110, and the backlight area 110 is color-converted by its corresponding optical film layer, and so on. That is, the entire backlight module 1000 performs the color homogenization, color conversion, and the like in units of the backlight area 110, and at this time, the side light of the backlight 200 in the backlight area 110 is reflected by the white dam 400 toward the substrate 100 after being incident on the white dam 400, so that the halation phenomenon can be prevented.

The backlight module 1000 has a plurality of backlight regions 110, and the plurality of backlight regions 110 correspond to black matrixes on the LCD one by one. Each backlight area 110 is surrounded by a circle of white dam 400, so that the color homogenization of each backlight area 110 is performed, and finally, the purpose of color homogenization of the whole backlight module 1000 is achieved.

Illustratively, the material of the white dam 400 includes any one of white dam glue, white photosensitive glue and white paint. Wherein, the white box dam glue can be prepared by a heat curing mode; the white photosensitive emulsion can be prepared by adopting an exposure mode, and the white coating can be prepared by adopting a transfer printing mode.

In some embodiments, a part of the white dam 400 may be shared between any two adjacent backlight regions 110 in the plurality of backlight regions 110, so that resources may be saved and costs may be reduced. Specifically, for example, if the backlight area 110 is square, the white dam 400 surrounding the backlight area 110 is also square, and the right side of the white dam 400 can be shared with the backlight area 110 and another backlight area 110 on the right side of the backlight area 110.

In some embodiments, the white dam 400 includes a top surface 410 and a bottom surface 420 oppositely disposed along the thickness direction Z of the backlight module 1000; the top surface 410 faces away from the optical film 300, and the bottom surface 420 is in contact with the optical film; in the width direction Y of the backlight module 1000, the size of the top surface 410 is smaller than the size of the bottom surface 420; the width direction Y is perpendicular to the thickness direction Z and perpendicular to the extending direction X of the white dam 400.

That is, the cross section of the white dam 400 has a shape with a narrow top and a wide bottom, and thus the white dam 400 has a strong structural stability and is not easily inclined or collapsed. In addition, the structure with the wide top and the narrow bottom is easier to process, and the light reflected by the peripheral wall faces the light-emitting surface, so that the light-emitting efficiency can be improved, and the light-emitting brightness can be increased.

Specifically, the cross section of the white dam 400 may be in a gentle slope shape, specifically, with reference to the direction in fig. 7, the upper edge and the lower edge of the cross section are parallel, the length of the upper edge is smaller than that of the lower edge, the left edge may protrude to the left side to form a slope shape, and the right edge may protrude to the right side to form a slope shape; or the left edge is concave towards the right and is in a slope shape, and the right edge is concave towards the left and is in a slope shape. And are not limiting in this application.

In some embodiments, in the width direction Y of the backlight module 1000, the cross-sectional shape of the white dam 400 is an isosceles trapezoid or an isosceles triangle; the width direction Y is perpendicular to the thickness direction Z of the backlight module 1000 and perpendicular to the extending direction X of the white dam 400. The extending direction X of the white dam 400 is a direction surrounding the backlight area 110 by one circle, taking the direction as reference in the drawing. The cross section of the white dam 400 is designed to be isosceles trapezoid or isosceles triangle, so that the processing is convenient, and the processing cost is reduced; and the structural stability of the white dam 400 can be increased.

Of course, in combination with the above-mentioned embodiment that the white dam 400 is required to be wide at the top and narrow at the bottom, when the cross-sectional shape of the white dam 400 is an isosceles trapezoid, the upper base edge of the isosceles trapezoid faces away from the optical film layer, and the lower base edge faces toward the optical film layer. When the cross-sectional shape of the white dam 400 is an isosceles triangle, the vertex of the isosceles triangle is away from the optical film layer, and the bottom edge of the isosceles triangle faces the optical film layer. It will of course be appreciated that the corners of the isosceles triangle are rounded to facilitate machining.

In some embodiments, the white dam 400 is raised relative to the surface of the optical film 300 facing away from the substrate 100 by a dimension greater than or equal to 10 microns. Therefore, the white dam 400 can play a supporting role and prevent the halation phenomenon. Specifically, the thickness of the protrusion of the white dam 400 is less than 10 μm, the side light of the backlight 200 may bypass the white dam 400 to form a halation phenomenon, and thus, the thickness of the white dam 400 is required to be greater than or equal to 10 μm. In some embodiments, there may be a case where a plurality of optical sheets 300 are stacked on one another, and the white dam 400 may play a role of supporting the optical sheets 300.

In some embodiments, the substrate 100 may be any one of a glass substrate, a silicon substrate, a printed circuit board, or a flexible circuit board, and may be selected according to actual needs, which is not limited in this embodiment.

In some embodiments, the optical film 300 includes a color conversion layer 310, a diffusion layer 320, and a reflective layer 330 stacked in this order from top to bottom; the diffusion layer 320 faces the white dam 400, and the reflection layer 330 faces the substrate 100. The reflective layer 330 can homogenize the intensity of the light emitted by the backlight, the diffusion layer 320 can make the color of the light emitted by the backlight more uniform, and the color conversion layer 310 can convert the blue light emitted by the blue light backlight 200 into red light or green light, thereby meeting the multi-color display requirements of the LCD. In addition, the color conversion layer 310 and the diffusion layer 320 may be separately prepared, that is, the diffusion layer 320 is prepared above the reflective layer 330, and then the color conversion layer 310 is prepared above the diffusion layer 320. Or a film layer is prepared above the reflecting layer 330, and the film layer has the functions of diffusion and color conversion at the same time, namely the color conversion layer 310 and the diffusion layer 320 are prepared by mixing; specifically, the color conversion layer 310 may be formed by adding reflective particles to a material for preparing the color conversion layer.

For example, the color conversion layer 310 may be a mixture of glue, color conversion material and diffusion particles, wherein the glue may be a silicon glue or an epoxy glue, the color conversion material may be color conversion material quantum dots or phosphor, and the diffusion particles may be silicon dioxide (SiO) ₂ ). The reflective layer 330 may be made of white paint or white ink.

In the thickness direction Z of the backlight module 1000, the size of the optical film 300 is greater than or equal to 63 micrometers and less than or equal to 330 micrometers. Specifically, the sum of the thicknesses of the diffusion layer 320 and the color conversion layer 310 is greater than or equal to 60 micrometers and less than or equal to 300 micrometers; the reflective layer 330 has a thickness greater than or equal to 3 micrometers and less than or equal to 30 micrometers.

Since the thickness of the backlight 200 is generally between 10 microns and 100 microns, the thickness of the optical film 300 is set between 63 microns and 330 microns, so that the optical film 300 can cover the backlight 200, and the thickness of the optical film 300 can be within a reasonable range, thereby reducing the thickness of the backlight module 1000 and saving resources.

Referring to fig. 8, fig. 8 is a cross-sectional view of a backlight module according to another embodiment of the present disclosure along a thickness direction. Another embodiment of the present application provides a backlight module 1000, which is different from the backlight module 1000 in the above embodiments in that the white dam 400 extends along the thickness direction Z of the backlight module 1000 to penetrate through the optical film 300 and is fixed to the surface of the substrate 100 on which the backlight 200 is disposed.

That is, the white dam 400 is thick, may penetrate the entire optical film 300, and is highly protruded from the optical film 300. Therefore, after the side light of the backlight 200 is emitted to the white dam 400, the side light can be reflected to the upper light-emitting surface by the white dam 400 and then emitted from the upper light-emitting surface. The setting mode can increase the light-emitting intensity, improve the light energy utilization rate and achieve the purpose of saving energy.

Referring to fig. 9, fig. 9 is a cross-sectional view of a backlight module according to another embodiment of the present application along a thickness direction. In another embodiment of the present disclosure, the backlight module 1000 is provided, wherein the white dam 400 may extend downward into the optical film layer, but does not penetrate through the optical film 300. More specifically, the white dam 400 may extend to be flush with the lower side edge of the side light emitting surface of the backlight 200, so that the white dam 400 may reflect the side light emitted from the backlight 200 to the upper light emitting surface as much as possible, and the thickness of the white dam 400 may be reduced, thereby saving resources.

Based on the backlight module 1000 provided in any of the above embodiments, an embodiment of the present application further provides an LCD, including the backlight module 1000 described in any of the above embodiments. Of course, it should be understood that the LCD may also include some LCD optical components, etc., and will not be described in detail.

It is to be understood that the invention is not limited to the examples described above, but that modifications and variations may be effected thereto by those of ordinary skill in the art in light of the foregoing description, and that all such modifications and variations are intended to be within the scope of the invention as defined by the appended claims.

Claims

1. A backlight module, comprising: the backlight module comprises a substrate, a backlight lamp, an optical film and a white dam;

one side surface of the substrate comprises a plurality of backlight areas, and a plurality of backlight lamps are arranged on the backlight areas; the optical film is laminated on the surface of the substrate provided with the backlight lamp and covers the backlight lamp;

the white dam is arranged around each backlight area, and the white dam is raised relative to the surface, away from the substrate, of the optical film.

2. A backlight module according to claim 1, wherein any two adjacent backlight regions share part of the white dam.

3. The backlight module according to claim 1, wherein the white dam comprises a top surface and a bottom surface oppositely arranged along a thickness direction of the backlight module; the top surface faces away from the optical film, the bottom surface is in contact with the optical film; in the width direction of the backlight module, the size of the top surface is smaller than that of the bottom surface.

4. The backlight module as claimed in claim 3, wherein the cross-sectional shape of the white dam is an isosceles trapezoid or an isosceles triangle.

5. The backlight module according to claim 1, wherein the white dam extends through the optical film in a thickness direction of the backlight module and is fixed to a surface of the substrate on which the backlight is disposed;

or the white dam extends into the optical film along the thickness direction of the backlight module, and the bottom surface of the white dam is flush with the edge of the side light outlet surface of the backlight lamp facing the substrate.

6. The backlight module as claimed in claim 1, wherein the white dam comprises any one of white dam glue, white photosensitive glue and white paint.

7. The backlight module according to any one of claims 1-6, wherein the white dam protrudes relative to the surface of the optical film sheet facing away from the substrate by a dimension greater than or equal to 10 μm.

8. The backlight module according to any one of claims 1 to 6, wherein the optical film comprises a color conversion layer, a diffusion layer and a reflection layer sequentially laminated from top to bottom; the diffusion layer faces the white dam, and the reflection layer faces the substrate.

9. The backlight module according to any one of claims 1 to 6, wherein the dimension of the optical film is greater than or equal to 63 micrometers and less than or equal to 330 micrometers in the thickness direction of the backlight module.

10. A liquid crystal display comprising the backlight unit according to any one of claims 1 to 9 and a plurality of liquid crystal layers,

the liquid crystal layers are stacked on the light emitting surface of the backlight module;

and the orthographic projection area of the frame of the liquid crystal layer on the substrate is superposed with the orthographic projection area of the white dam on the substrate.