Backlight module and display device

Abstract

The present invention provides a backlight module and a display device. The backlight module includes a light source component, a light guide plate, an adhesive, and a coating layer. The light guide plate includes a light incident surface facing the light source component, a first optical surface connected to the light incident surface, and a second optical surface connected to the light incident surface and opposite to the first optical surface. The adhesive includes a substrate, a first colloid located on one side of the substrate, and a second colloid arranged on the other side of the substrate, and the first colloid adheres the substrate to the first optical surface or the second optical surface of the light guide plate. The coating layer is arranged on the substrate and between the first surface and the first colloid, and the reflectivity of the coating layer is greater than the reflectivity of the light guide plate. The arrangement of the coating layer effectively improves the color difference problem of the backlight module.

Description

Technical Field

[0001] The invention relates to a light guide component and application thereof, and in particular to a backlight module and a display device. Background Art

[0002] Generally, a backlight module includes a light source, a frame, and a light guide plate. When the light guide plate and the frame are assembled, an optical adhesive is usually used on the light-entering side. However, optical adhesive has the characteristics of allowing light to penetrate and scatter, which causes large-angle light (such as yellow light) to hit the components below after penetrating the optical adhesive and scatter, making it easy for large-angle light to be emitted in advance of the front section of the light guide plate, resulting in a significant color difference between the light-emitting surface of the light guide plate that is closer to the light source and the light-emitting surface that is farther away from the light source. Therefore, the overall optical quality of the light guide plate is poor. Summary of the invention

[0003] Therefore, an object of the present invention is to provide a backlight module capable of improving the color difference problem.

[0004] The backlight module includes a light source component, a light guide plate, an adhesive, and a coating layer. The light source component includes a circuit board and at least one light-emitting component disposed on the circuit board. The light guide plate includes a light incident surface facing the light source component, a first optical surface connected to the light incident surface, and a second optical surface connected to the light incident surface and opposite to the first optical surface. The adhesive includes a substrate having a first surface and a second surface opposite to the first surface, a first colloid located on the first surface of the substrate, and a second colloid disposed on the second surface of the substrate, the first surface of the substrate facing the light guide plate, and the first colloid adheres the substrate to the first optical surface or the second optical surface of the light guide plate. The coating layer is disposed on the first surface of the substrate and is located between the first surface and the first colloid, and the reflectivity of the coating layer is greater than the reflectivity of the light guide plate.

[0005] Another technical means of the present invention is that the area of ​​the coating layer is smaller than the area of ​​the first surface of the substrate.

[0006] Another technical means of the present invention is that the substrate has a dimming area close to the light source component and a light-transmitting area adjacent to the dimming area and away from the light source component, the dimming area extends in the same direction as the light source component, and the coating layer is arranged in the dimming area and does not extend to the light-transmitting area.

[0007] Another technical means of the present invention is that the coating layer completely covers the dimming area.

[0008] Another technical means of the present invention is that the light source assembly includes a plurality of light-emitting assemblies arranged at intervals on the circuit board, the coating layer is arranged at intervals on the dimming zone, and the area in the dimming zone where the coating layer is not arranged corresponds to the area on the circuit board where the light-emitting assembly is not arranged.

[0009] Another technical means of the present invention is that the coating layer is mirror reflective.

[0010] Another object of the present invention is to provide another backlight module that can improve the color difference problem.

[0011] The backlight module includes a light source component, a light guide plate, and an adhesive. The light source component includes a circuit board, and a plurality of light-emitting components arranged on the circuit board at intervals. The light guide plate includes a light incident surface facing the light source component, a first optical surface connected to the light incident surface, and a second optical surface connected to the light incident surface and opposite to the first optical surface. The adhesive includes a substrate having a first surface and a second surface opposite to the first surface, a first colloid arranged on the first surface, and a second colloid arranged on the second surface, the first surface facing the light guide plate, the first colloid adheres the substrate to the first optical surface or the second optical surface of the light guide plate, wherein the reflectivity of the first surface of the substrate is greater than the reflectivity of the light guide plate.

[0012] Another technical means of the present invention is that the first surface of the substrate is specularly reflective.

[0013] Another object of the present invention is to provide a display device, including the aforementioned backlight module and a display panel arranged on the backlight module, the backlight module also includes an optical film group arranged on the light emitting surface of the light guide plate, and the display panel includes a visible area and a non-visible area.

[0014] Another technical means of the present invention is that the coating layer is located in the non-visible area.

[0015] Another object of the present invention is to provide another display device, comprising the aforementioned backlight module and a display panel arranged on the backlight module, the backlight module also comprising an optical film group arranged on the first optical surface of the light guide plate, and the display panel comprising a visible area and a non-visible area.

[0016] Another technical means of the present invention is that the substrate is located in the non-visible area.

[0017] The beneficial effect of the present invention is that the color difference problem of the backlight module and the display device is effectively improved by designing a coating layer or a substrate with a mirror reflection effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 is a schematic diagram illustrating a first embodiment of a backlight module of the present invention;

[0019] Figure 2 is a partial enlarged schematic diagram, which assists in explaining the structure and connection relationship between the adhesive member and the coating layer in the first embodiment;

[0020] Figure 3 is a graph illustrating a trend of CIE chromaticity table V' values ​​of the light guide plate of the first embodiment and a light guide plate without a coating layer;

[0021] Figure 4 is a schematic diagram illustrating different configurations of the light source assembly in the first embodiment;

[0022] Figure 5 is a schematic diagram illustrating the composition of the light source assembly and the configuration of the coating layer from a top view;

[0023] Figure 6 is a schematic diagram illustrating another configuration of the coating layer from a top view;

[0024] Figure 7 is a schematic diagram illustrating a display device according to a first embodiment of a backlight module of the present invention;

[0025] Figure 8 is a schematic diagram illustrating a second embodiment of a backlight module of the present invention;

[0026] Fig. 9 is a partially enlarged schematic diagram to assist in explaining the structure of the adhesive member in the second embodiment; and

[0027] Fig.10 FIG. 1 is a schematic diagram illustrating a display device according to a second embodiment of a backlight module of the present invention. DETAILED DESCRIPTION

[0028] The features and technical contents of the related patent applications of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the accompanying drawings. Before the detailed description, it should be noted that similar components are represented by the same number.

[0029] See also Figure 1 and Figure 2 , which is a first embodiment of the backlight module of the present invention, includes a light source assembly 120, a light guide plate 130, an adhesive 140, and a coating layer 150. The light guide plate 130 is made of polymethyl methacrylate (PMMA), and its refractive index is usually 1.49. In other embodiments, the light guide plate 130 can also be made of polycarbonate (PC), and the light guide plate 130 made of PC can also be called a light guide film, and its refractive index is usually 1.59.

[0030] The light guide plate 130 includes a light incident surface 131 facing the light source assembly 120, a first optical surface 132 connected to the light incident surface 131, and a second optical surface 133 connected to the light incident surface 131 and opposite to the first optical surface 132. In the embodiment of the present invention, one of the first optical surface 132 and the second optical surface 133 can be a light emitting surface, and the other opposite surface is a bottom surface. In the first embodiment, the first optical surface 132 is the light emitting surface, and the second optical surface 133 is the bottom surface.

[0031] The light source assembly 120 includes a circuit board 121 and a light emitting assembly 122 disposed on the circuit board 121. The circuit board 121 is a flexible printed circuit (FPC) covered with a coverlay, and the adhesive 140 is an optically clear adhesive (OCA) used to attach the light guide plate 130 to the coverlay of the circuit board 121. In this embodiment, the circuit board 121 is located below the light guide plate 130.

[0032] The adhesive 140 includes a substrate 141 having a first surface 142 and a second surface 143 opposite to the first surface 142, a first colloid 144 located on the first surface 142 of the substrate 141, and a second colloid 145 disposed on the second surface 143 of the substrate 141. The first surface 142 of the substrate 141 faces the second optical surface 133 of the light guide plate 130. The first colloid 144 adheres the substrate 141 to the second optical surface 133 of the light guide plate 130, and the second colloid 145 adheres the substrate 141 to the circuit board 121 of the light source assembly 120. The coating layer 150 is disposed on the first surface 142 of the substrate 141 and is located between the first surface 142 and the first colloid 144. The coating layer 150 has a specular reflection characteristic. More preferably, the reflectivity of the coating layer 150 is greater than the reflectivity of the light guide plate 130.

[0033] When the coating layer 150 is not provided, the light generated by the light emitting component 122 of the light source component 120, after entering the light incident surface 131 of the light guide plate 130, will sequentially penetrate the first colloid 144, the substrate 141 and the second colloid 145 of the adhesive 140, and the large-angle yellow light therein is more easily affected by the components with scattering characteristics below (such as the protective film of the circuit board 121), and the light is scattered in front of the second optical surface 133 of the light guide plate 130, resulting in the light output from one end of the light guide plate 130 adjacent to the light source component 120 being yellowish; refer to Figure 3, measure the V' value of the first optical surface 132 (the light emitting surface in this embodiment) of the light guide plate 130 on the CIE chromaticity table, take the light incident surface 131 as the reference (X = 0mm), measure the V' value at different positions, and compare it with the known light guide plate without coating layer (such as Figure 3 The color difference between the ◆ shown in the figure at 10mm and 100mm is 0.003.

[0034] like Figure 1 As shown, the present embodiment is provided with a coating layer 150 with a mirror reflection effect. When light enters the light guide plate 130, the yellow light with a large angle will also enter the first colloid 144 in the adhesive 140. However, because the coating layer 150 with a mirror reflection effect is located under the first colloid 144, the scattering effect caused by the components under the adhesive 140 can be reduced, so that the yellow light can still be reflected back to the light guide plate 130. Figure 3 As shown, it can be seen that the light guide plate 130 (such as Figure 3 The color difference between ▲) at 10mm and 100mm is reduced to 0.0012. It can be compared that the △ V' value of the light guide plate 130 provided with the coating layer 150 is significantly reduced, and the color difference is improved by about 60%. In this embodiment, the color difference between the light color of the front section of the first optical surface 132 (light emitting surface) of the light guide plate 130 and the light color of the middle section is small, and the present invention can indeed achieve the effect of improving the overall optical taste of the light guide plate 130. In addition, in this embodiment, in order to improve the reflectivity of the coating layer 150 and reflect more yellow light, silver plating can be used as the coating layer 150.

[0035] Also, see Figure 4 , the adhesive 140, the coating layer 150, and the circuit board 121 can also be arranged above the light guide plate 130, that is, the first colloid 144 adheres the substrate 141 to the first optical surface 132 of the light guide plate 130, the second colloid 145 adheres the substrate 141 to the circuit board 121 of the light source assembly 120, and the coating layer 150 is located between the substrate 141 and the first colloid 144. With this design, backlight modules of different designs can be adapted. Of course, if the circuit board 121 of a backlight module of a certain type does not extend to the position of the light guide plate 130, the adhesive 140 can also be adhered to other components (such as a frame) of the backlight module. This embodiment is only described and illustrated by taking the circuit board 121 as an example, and is not limited thereto.

[0036] It should be noted that the light emitting effect can be adjusted by changing the arrangement of the coating layer 150. Figure 5As shown, in this embodiment, the light source assembly 120 includes a circuit board 121, and a light emitting assembly 122 disposed on the circuit board 121. The area of ​​the coating layer 150 is smaller than the area of ​​the first surface 142 of the substrate 141. In more detail, the substrate 141 has a dimming area 146 close to the light source assembly 120, and a light-transmitting area 147 adjacent to the dimming area 146 and away from the light source assembly 120. The dimming area 146 extends in the same direction as the light source assembly 120. The coating layer 150 (the oblique line portion) is disposed in the dimming area 146 and does not extend to the light-transmitting area 147, and completely covers the dimming area 146. With this design, when the light emitting assembly 122 is a strip design, such as a lamp tube or a long strip phosphor package, the coating layer 150 can provide a more complete light reflection effect.

[0037] In addition, if Figure 6 As shown, in some embodiments, the light source assembly 120 includes a circuit board 121, and a plurality of light emitting assemblies 122, such as LEDs, disposed at intervals on the circuit board 121. The coating layer 150 is disposed at intervals on the dimming area 146, and the area in the dimming area 146 where the coating layer 150 is disposed corresponds to the area on the circuit board 121 where the light emitting assemblies 122 are disposed. By means of the aforementioned interval design, in addition to allowing the coating layer 150 to be disposed only for the position of the light emitting assemblies 122, the material usage of the coating layer 150 can be reduced, and the cost cannot be reduced due to the excessive silver plating area. At the same time, because the silver plating areas in the coating layer 150 are respectively located in the corresponding relationship in front of the light emitting assemblies 122, the maximum energy and light in front of the light emitting assemblies 122 can be reflected, which not only optimizes and solves the most obvious yellowing phenomenon in front of the light emitting assemblies 122, but also adjusts the light output between the bright area in front of the light emitting assemblies 122 and the adjacent dark area.

[0038] In addition, for the light entering the light guide plate 130, components with scattering characteristics (such as the protective film of the circuit board 121) will reduce the overall energy, resulting in reduced brightness. In particular, when the light guide plate 130 is made of PMMA (refractive index 1.49), the scattering energy here will be greater than the scattering energy of the light guide plate 130 (or light guide film) made of PC (refractive index 1.59). Therefore, when the coating layer 150 with a mirror reflection effect is set, the scattered energy can be reflected back into the light guide plate 130 to improve the brightness. Even for the light guide plate 130 made of PMMA (refractive index 1.49), the brightness improvement effect will be greater than the brightness improvement effect of the light guide plate 130 (or light guide film) made of PC (refractive index 1.59). In other words, the brightness improvement effect is inversely related to the refractive index of the light guide plate 130.

[0039] See also Figure 7 , is a schematic diagram showing a display device according to a first embodiment of the present invention, comprising the aforementioned backlight module, and a display panel 170 disposed on the backlight module. The backlight module further comprises an optical film group 160 disposed on the first optical surface 132 of the light guide plate 130. It should be particularly noted that the display panel 170 comprises a visible area 171 and a non-visible area 172, and the coating layer 150 is located in the non-visible area 172 to maintain a good visual experience of the display device.

[0040] See also Figure 8 , which is a second embodiment of the backlight module of the present invention, includes a light source assembly 220 , a light guide plate 230 , and an adhesive member 240 .

[0041] The light guide plate 230 includes a light incident surface 231 facing the light source assembly 220, a first optical surface 232 connected to the light incident surface 231, and a second optical surface 233 connected to the light incident surface 231 and opposite to the first optical surface 232. In the embodiment of the present invention, one of the first optical surface 232 and the second optical surface 233 can be a light emitting surface, and the other surface can be a bottom surface. In the second embodiment, the first optical surface 232 is the light emitting surface, and the second optical surface 233 is the bottom surface.

[0042] See also Figure 8 and Fig. 9 The adhesive 240 includes a substrate 241 having a first surface 242 and a second surface 243 opposite to the first surface 242, a first colloid 244 located on the first surface 242 of the substrate 241, and a second colloid 245 disposed on the second surface 243 of the substrate 241. The first surface 242 of the substrate 241 faces the second optical surface 233 of the light guide plate 230, and the first colloid 244 adheres the substrate 241 to the second optical surface 233 of the light guide plate 230. The first surface 242 of the substrate 241 has a mirror reflection effect, and more preferably, the reflectivity of the first surface 242 is greater than the reflectivity of the light guide plate 230.

[0043] In this embodiment, the first surface 242 of the substrate 241 has the characteristic of mirror reflection. Therefore, when the light enters the light guide plate 230, the yellow light with a large angle will be reflected by the mirror reflection effect of the first surface 242, thereby reducing the scattering effect caused by the components under the adhesive 240, so that the yellow light will still be reflected back to the light guide plate 230, improving the chromatic aberration phenomenon of the front section and the middle section of the first optical surface 232 (light emitting surface). In this embodiment, the coating layer of the first embodiment is not used, but the first surface 242 of the substrate 241 has the characteristic of mirror reflection. Under the condition of reducing the number of components, it can also achieve the situation of reducing the light emitting of one end of the light guide plate 230 adjacent to the light source component 220, and also has the technical effect of reducing the coating materials, saving the coating cost and the coating time.

[0044] See also Fig.10 , is a schematic diagram showing a display device according to a second embodiment of the present invention, comprising the aforementioned backlight module, and a display panel 270 disposed on the backlight module. The backlight module further comprises an optical film set 260 disposed on the first optical surface 232 of the light guide plate 230. It should be particularly noted that the display panel 270 comprises a visible area 271 and a non-visible area 272, and the substrate 241 is located in the non-visible area 272, so that the first surface 242 of the substrate 241 is also located in the non-visible area 272, so as to maintain a good visual experience of the display device.

[0045] In summary, it can be seen from the above-mentioned embodiments of the present invention that the present invention reduces the light emission phenomenon of large-angle light (such as yellow light) near the light incident surface of the light guide plate by setting the coating layer on the light emitting surface or the bottom surface near the light incident surface, or utilizing the first surface with a mirror reflection effect in the substrate, that is, reduces the yellowing phenomenon at the light incident point, thereby improving the overall optical taste, so the purpose of the present invention can indeed be achieved.

[0046] However, what is described above is only a preferred embodiment of the present invention, and should not be used to limit the scope of implementation of the present invention. That is, all simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the content of the invention description are still within the scope covered by the claims of the present invention.

[0047] Explanation of symbols

[0048] 120 Light source components

[0049] 121 Circuit Board

[0050] 122 Light emitting components

[0051] 130 Light guide plate

[0052] 131 Light incident surface

[0053] 132 First optical surface

[0054] 133 Second optical surface

[0055] 140 Adhesive

[0056] 141 Substrate

[0057] 142 First Surface

[0058] 143 Second Surface

[0059] 144 First Colloid

[0060] 145 Second Colloid

[0061] 146 dimming zones

[0062] 147 Translucent Area

[0063] 150 coating layer

[0064] 160 Optical Film Set

[0065] 170 Display Panel

[0066] 171 Viewing Area

[0067] 172 Non-visible area

[0068] 220 Light source assembly

[0069] 221 Circuit Board

[0070] 230 Light guide plate

[0071] 231 Light incident surface

[0072] 232 First optical surface

[0073] 233 Second optical surface

[0074] 240 Adhesives

[0075] 241 Substrate

[0076] 242 First Surface

[0077] 243 Second Surface

[0078] 244 First Colloid

[0079] 245 Second Colloid

[0080] 260 Optical Film Set

[0081] 270 Display Panel

[0082] 271 Viewing Area

[0083] 272 Non-visible area.

Claims

1. A backlight module, characterized in that include: A light source assembly, comprising a circuit board, and at least one light-emitting assembly disposed on the circuit board; A light guide plate, comprising a light incident surface facing the light source assembly, a first optical surface connected to the light incident surface, and a second optical surface connected to the light incident surface and opposite to the first optical surface; The adhesive member includes a substrate having a first surface and a second surface opposite to the first surface, a first colloid located on the first surface of the substrate, and a second colloid disposed on the second surface of the substrate, wherein the first surface of the substrate faces the light guide plate, and the first colloid adheres the substrate to the first optical surface or the second optical surface of the light guide plate; and The coating layer is disposed on the first surface of the substrate and is located between the first surface and the first colloid. The reflectivity of the coating layer is greater than the reflectivity of the light guide plate.

2. The backlight module according to claim 1, characterized in that: The arrangement area of ​​the coating layer is smaller than the first surface area of ​​the substrate.

3. The backlight module according to claim 2, characterized in that: The substrate has a dimming area close to the light source component and a light-transmitting area adjacent to the dimming area and away from the light source component. The dimming area and the light source component extend in the same direction. The coating layer is arranged in the dimming area and does not extend to the light-transmitting area.

4. The backlight module according to claim 3, characterized in that: The coating layer completely covers the dimming area.

5. The backlight module according to claim 3, characterized in that: The light source assembly includes a plurality of light emitting assemblies spaced apart on the circuit board, the coating layer spaced apart on the dimming zone, and an area in the dimming zone where the coating layer is not disposed corresponds to an area on the circuit board where the light emitting assemblies are not disposed.

6. The backlight module according to claim 1, characterized in that: The coating layer is specularly reflective.

7. A backlight module, characterized in that include: A light source assembly, comprising a circuit board, and at least one light-emitting assembly disposed on the circuit board; A light guide plate, comprising a light incident surface facing the light source assembly, a first optical surface connected to the light incident surface, and a second optical surface connected to the light incident surface and opposite to the first optical surface; and The adhesive comprises a substrate having a first surface and a second surface opposite to the first surface, a first colloid arranged on the first surface, and a second colloid arranged on the second surface, wherein the first surface faces the light guide plate, and the first colloid adheres the substrate to the first optical surface or the second optical surface of the light guide plate, wherein the reflectivity of the first surface of the substrate is greater than the reflectivity of the light guide plate.

8. The backlight module according to claim 7, characterized in that: The first surface of the substrate is specularly reflective.

9. A display device, characterized in that It comprises a backlight module according to any one of claims 1 to 6, and a display panel arranged on the backlight module, the backlight module also comprises an optical film group arranged on the first optical surface of the light guide plate, and the display panel comprises a visible area and a non-visible area.

10. The display device according to claim 9, characterized in that The coating layer is located in the non-visible area.

11. A display device, characterized in that It comprises a backlight module according to claim 7 or 8, and a display panel arranged on the backlight module, the backlight module also comprises an optical film group arranged on the first optical surface of the light guide plate, and the display panel comprises a visible area and a non-visible area.

12. The display device according to claim 11, characterized in that The substrate is located in the non-viewing area.

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