TWI692668B - Backlight module and display device - Google Patents

Abstract

A backlight module comprises a light source component, a light guide plate, an adhesive component, and a coating layer. The light guide plate includes a light incident surface, a first optical surface connected to the light incident surface, and a second optical surface opposite to the first optical surface. The adhesive member comprises a substrate, a first colloid on one side of the substrate, and a second colloid disposed on the other side of the substrate, the first colloid bonding the substrate to the first optical surface or the second optical surface of the light guide plate. The coating layer is disposed between the substrate and the first colloid, and the reflectivity of the coating layer is greater than the reflectivity of the light guide plate. The coating layer effectively improves the chromatic aberration problem of the backlight module. The invention also provides a display device including the backlight module.

Description

Backlight module and display device

The invention relates to a light guide element and its application, in particular to a backlight module and a display device.

Generally, the 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 glue (Optical Clear Adhesive) is usually used on the light entrance side. However, the optical glue has the characteristics of allowing light to penetrate and scatter, which causes large-angle light (such as yellow light) to be scattered after hitting the bottom member after passing through the optical glue, so that the large-angle light is easy to advance ahead of the front section of the light guide plate The light exit causes the light exit surface of the light guide plate closer to the light source and the light exit surface farther away from the light source. The color difference between the two is obvious, so the overall optical taste of the light guide plate is not good.

Therefore, an object of the present invention is to provide a backlight module that can improve the color difference problem.

The backlight module includes a light source component, a light guide plate, an adhesive member, and a coating layer. The light source assembly includes a circuit board and at least one light-emitting element disposed on the circuit board. The light guide plate includes 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 on the first surface of the substrate, and a second disposed on the substrate On the surface of the second colloid, 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. The plating The film layer is disposed on the first surface of the substrate and between the first surface and the first colloid. The reflectivity of the plated film layer is greater than that of the light guide plate.

Another technical means of the present invention is that the installation area of the plating layer is smaller than the first surface area of the substrate.

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 far away from the light source component, the dimming area is in contact with the light source component Extending in the same direction, the coating layer is disposed in the dimming area and does not extend to the light-transmitting area.

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

Another technical means of the present invention is that the light source assembly includes a plurality of light-emitting elements arranged on the circuit board at intervals, the coating layer is arranged on the dimming area at intervals, and the coating layer is not provided in the dimming area The area corresponding to is the area where the light-emitting element is not provided on the circuit board.

Another technical means of the present invention is that the coating layer is specularly reflected.

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

The backlight module includes a light source component, a light guide plate, and an adhesive member. The light source assembly includes a circuit board and a plurality of light-emitting elements arranged on the circuit board at intervals. The light guide plate includes 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 disposed on the first surface, and a second colloid disposed on the second surface , The first surface faces the light guide plate, the first colloid adheres the substrate to the first light of the light guide plate The scientific surface or the second optical surface, wherein the reflectance of the first surface of the substrate is greater than the reflectance of the light guide plate.

Another technical means of the present invention is that the first surface of the substrate is specularly reflected.

Another object of the present invention is to provide a display device including the aforementioned backlight module and a display panel disposed on the backlight module. The backlight module further includes an optical film set disposed on the guide On the light-emitting surface of the light board, the display panel includes a visible area and a non-visible area.

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

Another object of the present invention is to provide another display device including the aforementioned backlight module and a display panel disposed on the backlight module. The backlight module further includes an optical film set disposed on On the first optical surface of the light guide plate, the display panel includes a visible area and a non-visible area.

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

The beneficial effect of the present invention is to effectively improve the chromatic aberration problem of the backlight module and the display device through the design of a coating layer or a substrate with a mirror reflection effect.

120‧‧‧Light source assembly

121‧‧‧ circuit board

122‧‧‧Lighting element

130‧‧‧Light guide plate

131‧‧‧entrance

132‧‧‧First optical surface

133‧‧‧Second optical surface

140‧‧‧adhesive

141‧‧‧ base material

142‧‧‧First surface

143‧‧‧Second surface

144‧‧‧Colloid

145‧‧‧second colloid

146‧‧‧Dimming area

147‧‧‧Transparent area

150‧‧‧Coating layer

160‧‧‧Optical diaphragm set

170‧‧‧Display panel

171‧‧‧viewable area

172‧‧‧Invisible area

220‧‧‧Light source assembly

221‧‧‧ circuit board

230‧‧‧Light guide plate

231‧‧‧Into the light

232‧‧‧First optical surface

233‧‧‧Second optical surface

240‧‧‧adhesive

241‧‧‧ Base material

242‧‧‧First surface

243‧‧‧Second surface

244‧‧‧Colloid

245‧‧‧second colloid

260‧‧‧Optical diaphragm set

270‧‧‧Display panel

271‧‧‧Viewable area

272‧‧‧Invisible area

1 is a schematic diagram illustrating a first embodiment of the backlight module of the present invention; FIG. 2 is a partially enlarged schematic diagram to assist in explaining the structure and connection relationship between an adhesive member and a coating layer in the first embodiment; 3 is a graph illustrating the V'value trend diagram of the CIE chromaticity table of the light guide plate of the first embodiment and the light guide plate that does not use a coating layer; 4 is a schematic diagram illustrating the different arrangement of a light source assembly in the first embodiment; FIG. 5 is a schematic diagram illustrating the composition of the light source assembly and the arrangement of the coating layer from a top perspective; FIG. 6 is a A schematic diagram illustrating another arrangement of the coating layer from a top perspective; FIG. 7 is a schematic diagram illustrating the display device according to the first embodiment of the backlight module of the present invention; FIG. 8 is a schematic diagram illustrating the backlight of the present invention A second embodiment of the module; FIG. 9 is a partially enlarged schematic diagram to help explain the structure of an adhesive member in the second embodiment; and FIG. 10 is a schematic diagram illustrating the second implementation of the backlight module according to the present invention The display device shown in the example.

Relevant patent application features and technical content of the present invention will be clearly presented in the following detailed description of the preferred embodiments with reference to the drawings. Before making a detailed description, it should be noted that similar elements are represented by the same number.

Referring to FIGS. 1 and 2, it is the first embodiment of the backlight module of the present invention, which includes a light source assembly 120, a light guide plate 130, an adhesive member 140, and a coating layer 150. The light guide plate 130 is made of poly(methyl methacrylate, PMMA for short), and its refractive index is usually 1.49. In other embodiments, polycarbonate (Polycarbonate, PC for short) can also be used to make the light guide plate 130. The PC light guide plate 130 can also be called a light guide film, and its refractive index is usually 1.59.

The light guide plate 130 includes a light incident surface 131 facing the light source assembly 120, and 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 may be a light emitting surface, and the opposite surface is a bottom surface. In the first embodiment, the first optical surface 132 is a light emitting surface The second optical surface 133 is a bottom surface.

The light source assembly 120 includes a circuit board 121 and a light emitting element 122 disposed on the circuit board 121. The circuit board 121 is a flexible printed circuit (FPC), which is covered with a protective film (Coverlay), and the adhesive 140 is an optical grade transparent adhesive tape (Optically Clear Adhesive, OCA), which is used to guide the The light board 130 is attached to the protective film of the circuit board 121. In this embodiment, the circuit board 121 is located below the light guide plate 130.

The adhesive member 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 The 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, and the first colloid 144 connects the substrate 141 The second optical surface 133 of the light guide plate 130 is pasted, and the second glue 145 pastes the substrate 141 on 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, wherein the coating layer 150 has specular reflection characteristics, more preferably, the coating The reflectance of the layer 150 is greater than the reflectance of the light guide plate 130.

When the coating layer 150 is not provided, the light generated by the light emitting element 122 of the light source assembly 120 enters the light incident surface 131 of the light guide plate 130, and then the light will sequentially penetrate the first colloid of the adhesive member 140 144. After the base material 141 and the second colloid 145, the large-angle yellow light is more easily affected by the underlying components with scattering characteristics (such as the protective film of the circuit board 121) on the second optical surface 133 of the light guide plate 130 before The light is scattered by the segment, resulting in the phenomenon that the light emitted from the end of the light guide plate 130 adjacent to the light source assembly 120 will be yellowish; referring to FIG. 3, the first optical surface 132 of the light guide plate 130 is measured (in this embodiment, the light exit V) value of the CIE chromaticity table of the surface), using the light incident surface 131 as a reference (X=0mm), measuring the V'value at different positions, and compared with the conventional light guide plate without coating (as shown in Figure 3 Shown ◆) The color difference between 10mm and 100mm, the value of △V' is 0.003.

As shown in FIG. 1, in this embodiment, a coating layer 150 with a specular reflection effect is provided. When light enters the light guide plate 130, the yellow light with a large angle will enter the first colloid 144 in the adhesive 140, but Underneath the first colloid 144 is a coating layer 150 with a specular reflection effect, thereby reducing the scattering effect caused by the underlying member of the adhesive member 140, so that the yellow light will still be reflected back to the light guide plate 130; as shown in FIG. 3 It can be seen that the color difference between the light guide plate 130 (as shown in FIG. 3 ▲) at 10 mm and 100 mm at the light guide plate 130 with a coating layer 150 decreases its ΔV′ value to 0.0012. From this, it can be compared that the light guide plate 130 provided with the coating layer 150 has a significant decrease in the ΔV′ value, which improves the color difference of about 60%. In this embodiment, the first optical surface 132 of the light guide plate 130 ( (Light exit surface) The color difference between the color of the light in the front section and the color of the light in the middle section is small, and the present invention can indeed improve the optical taste of the light guide plate 130 as a whole. Moreover, in this embodiment, in order to improve the reflectivity of the plating layer 150 and reflect a greater proportion of yellow light, a silver plating method may be adopted as the plating layer 150.

In addition, referring to FIG. 4, the adhesive 140, the plating layer 150, and the circuit board 121 may also be disposed above the light guide plate 130, that is, the first colloid 144 adheres the substrate 141 to the 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 between. With this design, backlight modules of different types can be designed. when However, if the circuit board 121 of some types of backlight modules does not extend to the position of the light guide plate 130, the adhesive 140 may also be attached to other components of the backlight module (such as a frame). This embodiment only The circuit board 121 is used as an example for description and illustration, and is not limited thereto.

In particular, the light-emitting effect can be adjusted by changing the arrangement of the plating layer 150. As shown in FIG. 5, in this embodiment, the light source assembly 120 includes a circuit board 121 and a light-emitting element 122 disposed on the circuit board 121. The area of the plating 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 light source assembly 120 extends in the same direction. The coating layer 150 (diagonal 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 element 122 is in the form of a strip, such as a lamp tube or an elongated phosphor package, the coating layer 150 can provide a more complete light reflection effect.

In addition, as shown in FIG. 6, in some embodiments, the light source assembly 120 includes a circuit board 121 and a plurality of light-emitting elements 122 disposed on the circuit board 121 at intervals, such as LEDs. The coating layer 150 is disposed on the dimming area 146 at intervals, and the area in the dimming area 146 where the coating layer 150 is provided corresponds to the area on the circuit board 121 where the light emitting element 122 is provided. With the aforementioned spaced design, in addition to allowing the coating layer 150 to be provided only for the position of the light emitting element 122, the material consumption of the coating layer 150 can be reduced, and the silver plating area is too large to reduce costs. Because the silver-plated areas in the coating layer 150 are respectively located in front of the light-emitting element 122, they can reflect the maximum energy in front of the light-emitting element 122 and the light, not only for the light-emitting element 122 in front of the most obvious The yellowing phenomenon is optimized and solved, and the light-emitting element can also be carried out Adjust the light output between the bright area in front of 122 and the adjacent dark area.

In addition, for light entering the light guide plate 130, a member with scattering characteristics (such as the protective film of the circuit board 121) reduces the overall energy, resulting in a decrease in brightness. Especially when applied to the light guide plate 130 made of PMMA (refractive index 1.49), the scattering energy here will be greater than that applied to the light guide plate 130 (or light guide film) made of PC (refractive index 1.59) Of scattered energy. Therefore, when the coating layer 150 with a specular reflection effect is provided, 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 effect of increasing the brightness is greater than the effect of increasing the brightness of the light guide plate 130 (or light guide film) made of PC (refractive index 1.59), that is, the brightness enhancement effect of the light guide plate 130 and the refractive index of the light guide plate 130 The relationship is reverse.

Referring to FIG. 7, a schematic diagram of a display device according to the first embodiment of the present invention is shown, including the aforementioned backlight module, and a display panel 170 disposed on the backlight module. Wherein, the backlight module further includes an optical film set 160 disposed on the first optical surface 132 of the light guide plate 130. In particular, the display panel 170 includes a visible area 171 and a non-visible area 172. The coating layer 150 is located in the non-visible area 172 to maintain a good visual experience of the display device.

Referring to FIG. 8, 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.

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 third optical surface connected to the light incident surface 231 relative to the first optical surface 232二光面233. In the embodiment of the present invention, one of the first optical surface 232 and the second optical surface 233 may be a light-emitting surface, and the other surface is a bottom surface. In the second embodiment, the first optical surface 232 is The light exit surface, the second optical surface 233 is a bottom surface.

8 and 9, the adhesive member 240 includes a There is a first surface 242 and a substrate 241 opposite to the second surface 243 of the first surface 242, a first colloid 244 located on the first surface 242 of the substrate 241, and a substrate 241 disposed on the substrate 241 The second colloid 245 of the second surface 243, the first surface 242 of the substrate 241 is directed to the second optical surface 233 of the light guide plate 230, the first colloid 244 adheres the substrate 241 to the light guide plate 230 Second optical surface 233. The first surface 242 of the substrate 241 has a specular reflection effect. More preferably, the reflectance of the first surface 242 is greater than the reflectance of the light guide plate 230.

In this embodiment, the first surface 242 of the substrate 241 has the characteristics of specular reflection. Therefore, when light enters the light guide plate 230, the yellow light at a large angle will pass the specular reflection effect of the first surface 242, thereby The scattering effect caused by the lower member of the adhesive member 240 can be reduced, so that the yellow light can still be reflected back to the light guide plate 230, thereby improving the chromatic aberration phenomenon of the front and middle sections of the first optical surface 232 (light exit 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 characteristics of specular reflection, and the reduction of the number of components can also achieve the reduction of the The situation that the light guide plate 230 emits light at one end adjacent to the light source assembly 220 also has the technical effects of reducing coating materials, saving coating costs and coating man-hours.

Referring to FIG. 10, a schematic diagram of a display device according to a second embodiment of the present invention is shown, including the aforementioned backlight module, and a display panel 270 disposed on the backlight module. Wherein, the backlight module further includes an optical film group 260 disposed on the first optical surface 232 of the light guide plate 230. In particular, the display panel 270 includes a visible area 271 and a non-visible area 272, 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 In the area 272, to maintain a good visual experience of the display device.

In summary, the above embodiments of the present invention may It is known that the present invention reduces the light guide plate adjacent to the light incident surface by providing the coating layer on the light exit surface or bottom surface adjacent to the light incident surface, or by using the first surface having a specular reflection effect in the substrate The phenomenon of high-angle light (such as yellow light) light emission, that is, reducing the yellowing phenomenon at the light entrance, and thereby improving the overall optical taste, so it can indeed achieve the purpose of the invention.

However, the above are only the preferred embodiments of the present invention, which should not be used to limit the scope of the implementation of the present invention, that is, simple equivalent changes and modifications made according to the scope of the patent application of the present invention and the description of the invention, All of them are still covered by the patent of the present invention.

120‧‧‧Light source assembly

121‧‧‧ circuit board

122‧‧‧Lighting element

130‧‧‧Light guide plate

131‧‧‧entrance

132‧‧‧First optical surface

133‧‧‧Second optical surface

140‧‧‧adhesive

141‧‧‧ base material

144‧‧‧Colloid

145‧‧‧second colloid

150‧‧‧Coating layer

Claims (7)

A backlight module includes: a light source component, including a circuit board, and at least one light emitting element disposed on the circuit board; a light guide plate, including a light incident surface facing the light source component, and a light incident surface connected to the light incident component A first optical surface, and a second optical surface connected to the light incident surface and opposite to the first optical surface; an adhesive member includes a second surface having a first surface and a second surface opposite to the first surface Substrate, 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, the first A colloid adheres the substrate to the first optical surface or the second optical surface of the light guide plate; and a coating layer is disposed on the first surface of the substrate and between the first surface and the first colloid The installation area of the coating layer is smaller than the first surface area of the substrate, and the reflectivity of the coating layer is greater than the reflectivity of the light guide plate. The backlight module according to item 1 of the patent application scope, wherein the substrate has a dimming area close to the light source component, and a light-transmitting area adjacent to the dimming area and far away from the light source component, the dimming The zone extends in the same direction as the light source assembly, and the coating layer is disposed in the dimming zone and does not extend to the light-transmitting zone. The backlight module according to item 2 of the patent application scope, wherein the coating layer completely covers the dimming area. The backlight module according to item 2 of the patent application scope, wherein the light source assembly includes a plurality of light-emitting elements arranged on the circuit board at intervals, and the coating layer is The space is arranged on the dimming area, and the area where the plating layer is not provided in the dimming area corresponds to the area on the circuit board where the light emitting element is not provided. The backlight module according to item 1 of the patent application scope, wherein the coating layer is specularly reflected. A display device comprising a backlight module as described in any one of claims 1 to 5 and a display panel provided on the backlight module, the backlight module further comprising an optical film The sheet set is disposed on the first optical surface of the light guide plate, and the display panel includes a visible area and a non-visible area. The display device according to item 6 of the patent application scope, wherein the coating layer is located in the non-visible area.

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