CN209560120U - Diffusion plate, direct-lit backlight module and display device - Google Patents

Abstract

The utility model relates to the technical field of packaging, and specifically discloses a diffusion plate, a direct-type backlight module and a display device. The diffuser plate includes a light incident surface and a light output surface oppositely arranged, the light incident surface includes a plurality of arcuate structures connected in sequence, the arcuate structure is protruding outward, and the light output surface is a planar structure; the interior of the diffuser plate is provided with a number of diffusing particles for to scatter light. On the one hand, the curved surface structure of the light-incident surface of the diffusion plate can disrupt the light energy that is originally distributed regularly; The light energy is redistributed, the light energy distribution is more uniform, the shadow of the lamp and the dark area between the lamps are diluted, the shadow of the bracket on the atomized diffuser is improved, and the subjective visual effect is improved; at the same time, the design spacing of the LED is increased to reduce the LED Use the quantity purpose to significantly reduce the cost.

Description

Diffusion plate, direct-lit backlight module and display device

technical field

The utility model relates to the technical field of packaging, in particular to a diffusion plate, a direct-type backlight module and a display device.

Background technique

As shown in Figure 1, in a traditional direct-lit backlight module, a light-emitting unit and a bracket 1' are arranged on the backplane 2', a reflector 3' is arranged on the inner surface of the backplane 2', a diffuser plate 4' and a diaphragm 5' placed on the top platform of the back plate 2' and supported by the bracket 1', the light-emitting unit includes LED6' and the lens 7' covered on it, and a light mixing cavity is formed between the back plate 2' and the diffusion plate 4' . The light emitted by the light emitting unit is diffused and evenly lighted by the diffuser plate 4' and transformed into a surface light source with uniform brightness, which provides light for the picture display of the liquid crystal display panel.

As shown in Figure 2, set the light emitting angle of the lens 7' to α', and when the light spots formed by the projection of two adjacent LEDs 6' on the diffuser plate 4' are just tangent, the visual effect will reach the optimal state. If the light mixing distance is set to H', the theoretically optimal interval between adjacent LED6' is: L'=2H'/tan(90-α'/2), and the light output angle of lens 7' in the industry is 150°, it can be calculated by the above equation: L'≈7.5H'. Design according to this theoretical value, the cost of LED 6' and lens 7' is very high. Therefore, it is only possible to reduce the number of designs of LED6' and lens 7', that is, to increase the distance L' between adjacent LED6'. In this way, an uneven block distribution of light and shade will be formed on the diffuser plate 4', which is difficult for subjective viewing. In terms of performance, there is an 8' problem in the dark area between the lamps, the brightness uniformity is low, and the visual quality is poor. The design of the traditional direct-type backlight module is very dependent on the lens 7', and the lens 7' has a long development cycle and low manufacturing precision, which is difficult to meet the development needs of the direct-type backlight module.

In order to reduce the number of light-emitting units and reduce the cost, the light energy of LED6' passes through the secondary light distribution of lens 7' and presents a butterfly-shaped light output to expand the light output angle. The light distribution curve is shown in Figure 3. 'The relative light intensity in the side area is relatively high. Since it is difficult to accurately distribute the light intensity at all angles, uneven light and dark ring-shaped spots will be formed on the diffuser plate 4', and the subjective visual effect is manifested as regular distribution of light shadows. and 8' of dark space between lights. In order to optimize the visual effect, it is necessary to use a high-cost high-haze diffuser 4' and a high-configuration diaphragm 5' to shield the atomization, but the effect is not ideal, and the cost is significantly increased.

On the other hand, as shown in Figure 4, the light energy of the LED 6' goes out through the lens 7' and reaches the bracket 1', part of it is reflected back to the cavity, a small part is absorbed by the bracket 1', and part of it is refracted by the bracket 1' and reaches the diffusion plate 4' creates an offset. Due to the existence of reflection and absorption, the light energy passing through the bracket 1' will be weakened, and coupled with the existence of light offset, a regional light energy distribution with uneven brightness and darkness will be formed on the diffuser plate 4', that is, the shadow phenomenon of the bracket. A number of optical films such as diffusers and prisms must be used for brightness enhancement and shielding in order to present a relatively uniform visual effect, but the cost is high and the effect is poor.

As the design of direct-lit backlight modules becomes thinner and thinner, the light mixing distance H' becomes smaller, and the above problems become more prominent.

Utility model content

The first purpose of the present utility model is to provide a diffusion plate, which can make the distribution of light energy more uniform, thereby improving the subjective visual effect, reducing the number of LEDs and reducing the cost.

For this purpose, the utility model adopts the following technical solutions:

A diffuser plate, the diffuser plate includes a light incident surface and a light exit surface, the light exit surface and the light incident surface are arranged opposite to each other, the light incident surface includes a plurality of sequentially connected arc surface structures, and the arc surface structure faces The outer surface is convex, and the light emitting surface is a planar structure; inside the diffusion plate, there are a number of diffusion particles for scattering light.

As a preferred technical solution of the above diffusion plate, the diffusion particles are evenly distributed inside the diffusion plate.

As a preferred technical solution of the above diffuser plate, the diffuser plate is provided with edge portions on all four sides for installation with the back plate.

As a preferable technical solution of the above-mentioned diffuser plate, the width of the edge portion is not less than 3mm, and the thickness is not less than 0.8mm.

As a preferred technical solution of the above diffuser plate, the thickness of the edge portion is L1, the maximum thickness of the curved surface structure is L2, and the brightness uniformity of the light emitting unit is μ, if μ≥70%, then L1<L2≤ 2L1, if μ<70%, then 2L1<L2≤3L1.

As a preferred technical solution of the above-mentioned diffusion plate, the light mixing distance is H, the distance between two adjacent curved surface structures is L3, and the light exit angle of the lens is α, then L3=2(H-L2)*tan( α/2).

The second purpose of the present utility model is to provide a direct-lit backlight module, which can effectively solve problems such as lamp shadows, dark areas between lamps, and shadows on brackets, thereby improving subjective visual effects, maximizing the distance between LEDs, and reducing the number of LEDs. Minimized, significantly reducing costs.

For this purpose, the utility model adopts the following technical solutions:

A direct type backlight module, comprising a backplane, a light-emitting unit, a support and the above-mentioned diffusion plate, the diffusion plate is installed on the backplane, the light-emitting unit and the support are both arranged on the back The bottom of the plate is located on one side of the light-incident surface of the diffusion plate.

As a preferred technical solution of the direct type backlight module above, the supporting member is provided in multiples and is located directly below the apex of the arcuate structure, and the minimum gap between the supporting member and the arcuate structure is no greater than Less than 1.5mm.

As a preferred technical solution of the direct-lit backlight module, there are multiple light emitting units, and they are arranged one by one directly below the junction of two adjacent sections of the curved surface structure.

The third object of the present invention is to provide a display device with good subjective visual effect and low cost.

For this purpose, the utility model adopts the following technical solutions:

A display device, comprising the above-mentioned direct-lit backlight module.

Compared with the prior art, the utility model has the advantages and beneficial effects of:

The utility model provides a diffusion plate. The light-emitting surface of the diffusion plate is a plane structure, and the light-incoming surface is designed as a continuous arc surface structure. A number of diffusion particles are arranged inside the diffusion plate for scattering light. On the one hand, the curved surface structure of the light-incident surface of the diffusion plate can disrupt the light energy that is originally distributed regularly; The light energy is redistributed, the light energy distribution is more uniform, the shadow of the lamp and the dark area between the lamps are diluted, the shadow of the bracket on the atomized diffusion plate is improved, and the subjective visual effect is improved; at the same time, the design spacing of the LED is increased to reduce the LED Use the number of objects to significantly reduce costs.

The utility model also provides a direct-type backlight module, which can effectively solve problems such as lamp shadows, dark areas between lamps, and shadows of brackets, thereby improving subjective visual effects, realizing maximum LED spacing, LED The number of chips is minimized, which significantly reduces the cost; and the backlight module is compatible with a variety of lenses, effectively shortening the product development cycle.

The utility model also provides a display device, which has good subjective visual effect and low cost.

Description of drawings

FIG. 1 is a schematic structural view of a direct-lit backlight module in the prior art;

FIG. 2 is a schematic diagram of visual effects of a direct-lit backlight module in the prior art;

3 is a schematic diagram of a light distribution curve of a light emitting unit in the prior art;

Fig. 4 is a schematic diagram of the bracket shadow of the direct type backlight module in the prior art;

Fig. 5 is a schematic structural view of a direct-lit backlight module provided by a specific embodiment of the present invention;

Fig. 6 is a schematic structural view of a diffusion plate provided by a specific embodiment of the present invention;

Fig. 7 is a partially enlarged schematic diagram of a diffusion plate provided by a specific embodiment of the present invention;

Fig. 8 is a schematic diagram of the arrangement of test points during the brightness uniformity μ test provided by the specific embodiment of the present invention.

In the picture:

1'-bracket; 2'-back plate; 3'-reflector; 4'-diffuser; 5'-membrane; 6'-LED; 7'-lens; 8'-dark area;

1-diffusion plate; 11-light incident surface; 111-curved surface structure; 12-light exit surface; 13-diffusion particles; 14-lap edge;

2-back plate; 3-light-emitting unit; 4-support; 5-reflector; 6-optical film.

Detailed ways

The technical scheme of the utility model will be further described below in conjunction with the accompanying drawings and through specific embodiments. It can be understood that the specific embodiments described here are only used to explain the utility model, rather than limit the utility model. It should also be noted that, for the convenience of description, only the parts related to the present utility model are shown in the drawings but not all of them.

In the description of the present utility model, unless otherwise clearly stipulated and limited, the terms "connected" and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral body; it can be A mechanical connection can also be an electrical connection; it can be a direct connection or an indirect connection through an intermediary, and it can be an internal communication between two components or an interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the present utility model according to specific situations.

Some orientation words are defined in the utility model, and in the case of no contrary description, the orientation words used are such as "center", "upper", "lower", "front", "back", "left", " "Right" means that the diffusion plate provided by the utility model is defined under normal use and is consistent with the orientation or positional relationship shown in the drawings. "Inside" and "Outside" refer to the inside and outside relative to the outline of each part itself. These orientation words are only for the convenience of description and simplification of operation, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and thus do not constitute a limitation on the protection scope of the present utility model. In addition, the terms "first" and "second" are used for descriptive purposes only, and should not be construed as indicating or implying relative importance.

This embodiment provides a display device, which may be a television, a display, an advertising machine, etc., and the display device includes a backlight module and a display panel arranged above the backlight module. The backlight module provides a backlight with uniform brightness for the display device, and the display panel controls the display of each pixel by controlling the light passing through each pixel, thereby displaying images. In this embodiment, as shown in FIG. 5, the backlight module is a direct type backlight module, which includes a backplane 2, a light-emitting unit 3, a support 4, a reflection sheet 5, a diffusion plate 1, and an optical film 6. The sheet 5 is installed on the inner surface of the back plate 2, the diffuser plate 1 is installed on the top of the cavity of the back plate 2, the edge of the back plate 2 is turned up and connected with the diffuser plate 1, and the optical film 6 is arranged on the diffuser plate 1 On the surface, a light mixing cavity is formed between the reflection sheet 5 and the diffuser plate 1, and the light emitting unit 3 and the support member 4 are arranged in the light mixing cavity. The light emitting unit 3 includes LEDs and lenses.

As shown in Fig. 6 and Fig. 7, the diffuser plate 1 in this embodiment includes a light incident surface 11 and a light exit surface 12, the light exit surface 12 and the light incident surface 11 are arranged oppositely, and the light incident surface 11 comprises a plurality of sequentially connected arcuate surface structures 111 , the arc surface structure 111 is protruding outward, and the light emitting surface 12 is a planar structure; inside the diffusion plate 1 are arranged a number of diffusion particles 13 for scattering light. The light entering the diffusion plate 1 undergoes several reflections and refractions under the action of the internal diffusion particles 13 to achieve sufficient scattering, redistribute the light energy, and make the light energy distribution more uniform.

The diffuser plate 1 provided in this embodiment is different from the traditional flat diffuser plate 4'. Its light incident surface 11 is designed as a continuous arc structure 111. On the one hand, the arc structure 111 can disrupt the originally regularly distributed light energy. On the other hand, the diffusion effect of the diffusion plate 1 depends on the organic diffusion particles 13 inside it, and the curved surface structure 111 increases the number of diffusion particles 13 in a local area, which can make the light incident on the diffusion plate 1 achieve more sufficient scattering. In this way, the light energy can be redistributed, the light energy can be distributed more uniformly, the shadows of the lamps and the dark area between the lamps, and the shadow of the bracket on the atomized diffuser plate 1 can be diluted, and the subjective visual effect can be effectively improved; at the same time, the design distance of the LEDs can be increased so that The purpose of reducing the number of LEDs used is to significantly reduce costs. The direct-lit backlight module provided in this embodiment adopts the aforementioned diffusion plate 1 , which improves lens compatibility and effectively shortens the product development cycle.

Furthermore, as shown in FIG. 7 , in order to improve the uniformity of light energy scattering and obtain a more uniform light extraction effect, the diffusion particles 13 are uniformly distributed inside the diffusion plate 1 . In actual production, the density of the diffusion particles 13 in the diffusion plate 1 is extremely high, and the uniform distribution state is the ideal distribution state.

In this embodiment, as shown in FIG. 6 , edge portions 14 are provided around the diffuser plate 1 for installation with the back plate 2 . Furthermore, as shown in FIG. 6 , the width of the lap portion 14 is not less than 3 mm, and the thickness is not less than 0.8 mm, so as to ensure the stability of assembly with the backplane 2 . The diffuser plate 1 can be formed integrally through a mold, and the technology is mature.

The specific design dimensions of the curved surface structure 111 on the light incident surface 11 of the diffuser plate 1 will be described in detail below. As shown in Figure 5, the light mixing distance is set to be H, the thickness of the edge portion 14 is L1, the maximum thickness of the arcuate structure 111 is L2, and the distance between two adjacent arcuate structures 111 (two arcuate structures The distance between the vertices of 111) is L3, and the light emitting angle of the lens is α, then L3=2(H−L2)*tan(α/2). Therefore, on the premise that the light mixing distance H and the lens light exit angle α are known, as long as the value of L2 is known, the design distance L3 of the arcuate structure 111 can be calculated.

However, the maximum thickness L2 of the curved surface structure 111 needs to be designed according to the brightness uniformity μ of the light emitting unit 3 . When measuring μ, a traditional flat diffuser plate 4' is needed. As shown in Figure 8, on the traditional flat diffuser plate 4', a rectangular light shadow range is delineated according to the subjective visual effect, within this range, nine test points P1-P9 are taken as shown in Figure 8, and the nine test points are tested respectively. The brightness value of each test point, and then calculate the brightness uniformity μ, the calculation formula is μ=min(P1:P9)/max(P1:P9); and then design the maximum thickness L2 of the arcuate structure 111 according to the value of μ. Specifically, if μ≧70%, then L1<L2≦2L1, and if μ<70%, then 2L1<L2≦3L1. Generally, the value of L2 is an integer multiple of L1. It should be noted that the layout of the nine test points needs to be designed according to the actual size of the diffuser plate 4', as shown in Figure 8, the size of the diffuser plate 4' is A*B, then the layout of the test points must meet the requirements shown in Figure 8. The positional relationship shown in 8.

In the direct-lit backlight module provided in this embodiment, both the light emitting unit 3 and the supporting member 4 are disposed at the bottom of the back plate 2 and on the side of the light incident surface 11 of the diffuser plate 1 . Furthermore, a plurality of support members 4 are provided and located directly below the apex of the arcuate structure 111 , and the minimum gap between the support member 4 and the arcuate structure 111 is not less than 1.5 mm. This structural arrangement can effectively improve the shading phenomenon of the support member 4 . In this embodiment, the position of the support member 4 is adjusted according to the specific size of the diffuser plate 1 , and there is no one-to-one correspondence between the support member 4 and the arc surface structure 111 . Optionally, in this embodiment, the support member 4 is preferably a conical support frame.

Optionally, there are a plurality of light emitting units 3, and they are arranged one by one directly below the junction of two adjacent segments of the arc structure 111 . This structure is set according to the butterfly-shaped light output law of the light emitting unit 3. Since the relative light intensity of the front area of the light emitting unit 3 is low and the relative light intensity of the side area is relatively high, the light emitting unit 3 is arranged directly below the place where the thickness of the diffuser plate 1 is the smallest. , so that the light energy in the front area hits the thinnest part of the light incident surface 11, and the light energy in the side area hits the arc surface structure 111 (the thickest part) of the light incident surface 11, which can improve the uniformity of light energy distribution, Thereby effectively improving the light and dark consistency of the light.

Apparently, the above-mentioned embodiments of the present utility model are only examples for clearly illustrating the present utility model, rather than limiting the embodiments of the present utility model. For those of ordinary skill in the art, other changes or changes in different forms can be made on the basis of the above description. It is not necessary and impossible to exhaustively list all the implementation manners here. All modifications, equivalent replacements and improvements made within the spirit and principles of the utility model shall be included in the protection scope of the claims of the utility model.

Claims (10)

1. A diffuser plate, characterized in that, the diffuser plate (1) comprises a light-incident surface (11) and a light-exit surface (12), and the light-exit surface (12) and the light-incidence surface (11) are relatively arranged , the light-incident surface (11) includes a plurality of arc-shaped structures (111) connected in sequence, the arc-surface structures (111) protrude outward, and the light-exit surface (12) is a planar structure; the diffusion plate ( 1) A number of diffusing particles (13) are arranged inside to scatter light. 2. The diffusion plate according to claim 1, characterized in that, the diffusion particles (13) are evenly distributed inside the diffusion plate (1). 3 . The diffuser plate according to claim 1 , characterized in that, edge portions ( 14 ) are provided around the diffuser plate ( 1 ) for installation with the back plate ( 2 ). 4 . 4. The diffuser plate according to claim 3, characterized in that, the width of the edge portion (14) is not less than 3mm, and the thickness is not less than 0.8mm. 5. The diffusion plate according to claim 3, characterized in that, the thickness of the edge portion (14) is L1, the maximum thickness of the curved surface structure (111) is L2, and the brightness of the light emitting unit (3) is The uniformity is μ, if μ≥70%, then L1<L2≤2L1, if μ<70%, then 2L1<L2≤3L1. 6. The diffuser plate according to claim 5, characterized in that, the light mixing distance is H, the distance between two adjacent curved surface structures (111) is L3, and the light output angle of the lens is α, then L3 =2(H-L2)*tan(α/2). 7. A direct type backlight module, characterized in that it comprises a backplane (2), a light emitting unit (3), a support (4) and a diffuser plate (1) according to any one of claims 1-6 , the diffusion plate (1) is installed on the back plate (2), the light emitting unit (3) and the support member (4) are both arranged at the bottom of the back plate (2) and located in the diffusion The side of the light incident surface (11) of the board (1). 8. The direct type backlight module according to claim 7, characterized in that there are multiple supports (4) located directly below the apex of the arc structure (111), and the supports The minimum gap between the piece (4) and the arc surface structure (111) is not less than 1.5mm. 9. The direct-lit backlight module according to claim 7, characterized in that there are multiple light-emitting units (3), and they are arranged in two adjacent sections of the curved surface structure (111) in one-to-one correspondence. directly below the connection. 10. A display device, characterized by comprising the direct-lit backlight module according to any one of claims 7-9.