Backlight module

Abstract

The present application provides a backlight module, which includes a light guide element, a light emitting element, a back plate, a light absorbing element and a reflecting element. The light guide element has a bottom surface, a light emitting surface opposite to the bottom surface and a light entering surface connecting the bottom surface and the light emitting surface. The light emitting element is disposed beside the light entering surface of the light guide element. The back plate has a receiving space. The light emitting element and the light guide element are disposed in the receiving space. The light absorbing element is disposed between the light emitting element and the back plate. The light absorbing element includes a glue material disposed on the back plate and a light absorbing base material disposed on the glue material. The light absorbing base material is located between the light guide element and the glue material. The light absorbing base material has an extension part protruding outside the side wall of the glue material. The extension part of the light absorbing base material, the side wall of the glue material and the back plate define a glue-free area. The reflecting element is disposed on the back plate. The end part of the reflecting element is inserted into the glue-free area. The backlight module of the present application can reduce the light entering side halo caused by glue overflow.

Description

Technical Field

[0001] This invention relates to a backlight module. Background Technology

[0002] With the development of display technology, in addition to continuously improving resolution, display devices are becoming increasingly thinner and lighter. Furthermore, the bezels of display devices are trending towards ultra-narrow bezels, or even borderless designs. As the bezels of display devices become narrower, the bezels of the backlight modules within the devices must also become narrower. However, as the bezels of the backlight modules become narrower, the distance between the light-emitting elements and the effective light-emitting area of ​​the backlight module also becomes closer. This causes a bright halo to appear on the light-incident side of the effective light-emitting area of ​​the backlight module, corresponding to the position of the light-emitting element, affecting the overall look and feel of the display device.

[0003] Generally, to solve the problem of screen halos at the location of the light-emitting element, light-absorbing tape is applied to the reflective sheet of the backlight module to absorb part of the light beam from the light-emitting element, thereby improving the screen halos at that location. However, due to limitations in the cutting process and / or differences in the thickness of the release film, the adhesive material of the light-absorbing tape can easily overflow from the light-absorbing substrate, causing halos to appear on the light-incident side of the effective light-emitting area of ​​the backlight module at the location of the overflowing adhesive.

[0004] The "Background Art" paragraph is only used to help understand the content of this invention. Therefore, the content disclosed in the "Background Art" paragraph may include some background art that is not known to those skilled in the art. The content disclosed in the "Background Art" paragraph does not represent the problems to be solved by such content or one or more embodiments of this invention, nor does it represent that it was known or recognized by those skilled in the art before this application was filed. Summary of the Invention

[0005] This invention provides a backlight module that can improve the problem of halos on the light-incident side caused by excess adhesive.

[0006] Other objects and advantages of the present invention can be further understood from the technical features disclosed herein. The backlight module of the present invention includes a light guide element, a light-emitting element, a backplate, a light-absorbing element, and a reflective element. The light guide element has a bottom surface, a light-emitting surface opposite to the bottom surface, and a light-incident surface connecting the bottom surface and the light-emitting surface. The light-emitting element is disposed next to the light-incident surface of the light guide element. The backplate has an accommodating space. The light-emitting element and the light guide element are disposed in the accommodating space. The light-absorbing element is disposed at least between the light-emitting element and the backplate. The light-absorbing element includes an adhesive material disposed on the backplate and a light-absorbing substrate disposed on the adhesive material. The light-absorbing substrate is located between the light guide element and the adhesive material. The light-absorbing substrate has an extension protruding beyond the sidewall of the adhesive material, and the extension of the light-absorbing substrate, the sidewall of the adhesive material, and the backplate define a non-adhesive area. The reflective element is disposed on the backplate. The end of the reflective element is inserted into the non-adhesive area.

[0007] Based on the above, since the end of the reflective element of the backlight module is inserted into the glue-free area under the light-absorbing substrate, the adhesive of the light-absorbing element is not easy to overflow outside the light-absorbing substrate, and the problem of bright halo on the light-incident side of the backlight module caused by adhesive overflow can be improved. Attached Figure Description

[0008] Figure 1 This is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention.

[0009] Figure 2 This is a top view and perspective schematic diagram of a backlight module according to an embodiment of the present invention.

[0010] Figure 3 This is a top view and perspective view of the backlight module according to another embodiment of the present invention.

[0011] Figure 4 This is a cross-sectional schematic diagram of a backlight module according to another embodiment of the present invention.

[0012] List of reference numerals

[0013] 10, 10A, 10B: Backlight modules

[0014] 110: Light guide element

[0015] 111, 151: end

[0016] 112: Bottom surface

[0017] 114: Exposed surface

[0018] 116: Light-receiving surface

[0019] 120: Light-emitting element

[0020] 130: Backplate

[0021] 130a: Accommodation space

[0022] 131: Bottom

[0023] 131s1, 141s1, 141s2: Surface

[0024] 132: Side wall portion

[0025] 133: Top

[0026] 140, 140A: Light-absorbing element

[0027] 141: Light-absorbing substrate

[0028] 141a, 141aA: Extension

[0029] 141a1: Arc-shaped region

[0030] 141b: Main part

[0031] 142: Adhesive Material

[0032] 142s3, 150s3: Sidewall

[0033] 150: Reflective element

[0034] 160: Flexible Printed Circuits

[0035] 170: Optical film

[0036] g: Spacing

[0037] NA: Glue-free area

[0038] T142, T150: Thickness

[0039] W1: First width

[0040] W2: Second width

[0041] x: direction

[0042] θ: Angle. Detailed Implementation

[0043] The foregoing and other technical contents, features, and effects of the present invention will be clearly presented in the following detailed description of a preferred embodiment with reference to the accompanying drawings. The directional terms mentioned in the following embodiments, such as up, down, left, right, front, or back, are merely for reference to the directions in the accompanying drawings. Therefore, the directional terms used are for illustrative purposes and not for limiting the present invention.

[0044] Figure 1 This is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 2 This is a top view and perspective schematic diagram of a backlight module according to an embodiment of the present invention. Figure 2 The backlight module 10 is shown with light-emitting element 120, light-absorbing element 140 and reflective element 150, while other components of the backlight module 10 are omitted.

[0045] Please refer to Figure 1The backlight module 10 includes a light guide element 110 and a light-emitting element 120. The light guide element 110 has a bottom surface 112, a light-emitting surface 114 opposite to the bottom surface 112, and a light-incident surface 116 connecting the bottom surface 112 and the light-emitting surface 114. The light-emitting element 120 is disposed next to the light-incident surface 116 of the light guide element 110. The light-incident surface 116 is the side surface of the light guide element 110. The light-emitting surface 114 of the light guide element 110 is the top surface of the light guide element 110. The light beam (not shown) emitted by the light-emitting element 120 enters the light guide element 110 from its side surface and exits from its top surface. In short, the backlight module 10 is a side-lit backlight module. The material of the light guide element 110 is, for example, a light-transmitting material such as polymethyl methacrylate (PMMA) or polycarbonate (PC). The light-emitting element 120 is, for example, a light-emitting diode, but is not limited thereto. In another embodiment, the light-emitting element 120 may also be replaced by a lamp tube.

[0046] In this embodiment, the backlight module 10 further includes a flexible printed circuit 160, which is electrically connected to the light-emitting element 120. In this embodiment, the flexible printed circuit 160 may be selectively disposed on the top surface (i.e., the light-emitting surface 114) of the light guide element 110. That is, the backlight module 10 in this embodiment may be selectively an inverted side-lit backlight module, but the present invention is not limited thereto.

[0047] In this embodiment, the backlight module 10 further includes at least one optical film 170, which is disposed on the light-emitting surface 114 of the light guide element 110. For example, in this embodiment, the at least one optical film 170 may be selected from a diffuser, a brightness enhancement film (BEF), a dual brightness enhancement film (DBEF), a prism sheet, or a combination thereof, but the present invention is not limited thereto.

[0048] In this embodiment, a portion of the flexible printed circuit 160 may be selectively disposed on at least one optical film 170, wherein the at least one optical film 170 is located between a portion of the flexible printed circuit 160 and the light guide element 110. However, the invention is not limited thereto; in other embodiments, a portion of the flexible printed circuit 160 may also be directly disposed on the light guide element 110.

[0049] The backlight module 10 also includes a backplate 130, which has an accommodating space 130a, in which the light-emitting element 120 and the light-guiding element 110 are disposed. Specifically, in this embodiment, the backplate 130 may include a bottom 131 and a sidewall portion 132, wherein the bottom 131 and the sidewall portion 132 are spaced at an angle θ to define the accommodating space 130a. In this embodiment, the backplate 130 may also optionally include a top 133, with both ends of the sidewall portion 132 connected to the top 133 and the bottom 131 respectively. The top 133 shields the light-emitting element 120 and exposes at least a portion of the light-emitting surface 114 of the light-guiding element 110. In this embodiment, a portion of the flexible printed circuit 160 electrically connected to the light-emitting element 120 may be sandwiched between the top 133 of the backplate 130 and the light-emitting surface 114 of the light-guiding element 110, but the invention is not limited thereto.

[0050] The backlight module 10 also includes a light-absorbing element 140, which is at least disposed between the light-emitting element 120 and the back plate 130. In this embodiment, in addition to being disposed between the light-emitting element 120 and the bottom 131 of the back plate 130, the light-absorbing element 140 is also disposed between the end 111 of the light guide element 110 near the light-incident surface 116 and the side wall portion 132 of the back plate 130, but the present invention is not limited thereto.

[0051] Please refer to Figure 1 and Figure 2 The light-absorbing element 140 includes a light-absorbing substrate 141 and an adhesive material 142. The adhesive material 142 is disposed on a back plate 130. The light-absorbing substrate 141 is disposed on the adhesive material 142 and is located between the light guide element 110 and the adhesive material 142. Notably, the light-absorbing substrate 141 has an extension 141a protruding beyond the sidewall 142s3 of the adhesive material 142, wherein the extension 141a of the light-absorbing substrate 141, the sidewall 142s3 of the adhesive material 142, and the back plate 130 define an adhesive-free area NA. The light-absorbing substrate 141 is, for example, light-shielding Mylar, but is not limited thereto. The adhesive material 142 can be an elastomer-type pressure-sensitive adhesive or a resin-type pressure-sensitive adhesive, such as natural rubber, synthetic rubber, acrylic, silicone, and polyurethane.

[0052] In this embodiment, the sidewall 142s3 of the adhesive material 142 defining the adhesive-free area NA can be located below the end 111 of the light guide element 110 near the light incident surface 116. That is, in this embodiment, the adhesive material 142 of the light-absorbing element 140 can extend from below the light-emitting element 120 to below the light guide element 110, overlapping with the end 111 of the light guide element 110 near the light incident surface 116. Furthermore, in this embodiment, the light-absorbing substrate 141 is disposed on the adhesive material 142 and has an extension 141a protruding beyond the sidewall 142s3 of the adhesive material 142, wherein the extension 141a extends in a direction away from the adhesive material 142. The light guide element 110 can be disposed between the flexible printed circuit 160 and the light-absorbing substrate 141, and a portion of the flexible printed circuit 160 can overlap the adhesive-free area NA.

[0053] In this embodiment, the light-absorbing substrate 141 has a main portion 141b in addition to the extension portion 141a, wherein the main portion 141b overlaps the adhesive material 142. In this embodiment, the main portion 141b and the extension portion 141a of the light-absorbing substrate 141 have a first width W1 and a second width W2 respectively in a direction x parallel to the light-emitting surface 114, and 1 / 3≤W2 / W1≤1 / 2, but the present invention is not limited thereto.

[0054] The backlight module 10 also includes a reflective element 150, which is disposed on the back plate 130, wherein one end 151 of the reflective element 150 is inserted into the adhesive-free area NA. That is, the end 151 of the reflective element 150 is sandwiched between the extension 141a of the light-absorbing substrate 141 and the bottom 131 of the back plate 130.

[0055] In this embodiment, during the assembly of the backlight module 10, the adhesive 142 of the light-absorbing element 140 can be first attached to the back plate 130, so that the extension 141a of the light-absorbing substrate 141, the sidewall 142s3 of the adhesive 142, and the bottom 131 of the back plate 130 form a glue-free area NA surrounded by the three. Then, the end 151 of the reflective element 150 is inserted into the glue-free area NA. In this way, if the backlight module 10 needs to be reworked, the reflective element 150 can be easily pulled out from the glue-free area NA. The pulled-out reflective element 150 is not easily scrapped due to residual adhesive or other damage, and the pulled-out reflective element 150 can be reused, thereby effectively improving the maintainability of the production line and reducing rework costs.

[0056] More importantly, since the end 151 of the reflective element 150 is the adhesive-free area NA inserted under the extension 141a of the light-absorbing substrate 141, the adhesive 142 of the light-absorbing element 140 is less likely to overflow from the light-absorbing substrate 141, thus improving the halo effect on the light-incident side of the backlight module caused by adhesive overflow. Furthermore, since the extension 141a of the light-absorbing substrate 141 can protrude beyond the adhesive 142, the light-absorbing element 140 is easier to manufacture and has a higher yield, thereby reducing the production cost of the light-absorbing element 140. Moreover, the light-absorbing element 140 can be attached to the backplate 130 before subsequent assembly steps, which also helps simplify the material preparation process on the production line.

[0057] In this embodiment, the thickness T142 of the adhesive 142 of the light-absorbing element 140 can be greater than or equal to the thickness T150 of the reflective element 150, so that one end 151 of the reflective element 150 can be easily inserted into the adhesive-free area NA, but the present invention is not limited thereto.

[0058] In this embodiment, the end portion 151 of the reflective element 150 is inserted into the adhesive-free area NA, so the extension portion 141a of the light-absorbing substrate 141 can directly contact and cover the end portion 151 of the reflective element 150. Furthermore, in this embodiment, the two opposing surfaces 141s1 and 141s2 of the extension portion 141a of the light-absorbing substrate 141 can respectively directly contact the light guide element 110 and the reflective element 150.

[0059] In this embodiment, the light-absorbing substrate 141 has a surface 141s2 facing the back plate 130, and the adhesive 142 and the reflective element 150 are in direct contact with the surface 141s2 of the light-absorbing substrate 141. In this embodiment, the back plate 130 has a surface 131s1 facing the bottom surface 112 of the light-guiding element 110, and the adhesive 142 and the reflective element 150 are in direct contact with the surface 131s1 of the back plate 130.

[0060] In this embodiment, the sidewall 150s3 of the reflective element 150 is disposed below the light-absorbing substrate 141 and faces the sidewall 142s3 of the adhesive material 142. In this embodiment, the sidewall 150s3 of the reflective element 150 may selectively directly contact the sidewall 142s3 of the adhesive material 142. However, the present invention is not limited thereto. In other embodiments, the sidewall 150s3 of the reflective element 150 may not contact the sidewall 142s3 of the adhesive material 142. Examples will be given below with reference to other figures.

[0061] It must be noted that the following embodiments use the component reference numerals and some content from the foregoing embodiments, with the same reference numerals used to represent the same or similar components, and descriptions of the same technical content omitted. For explanations of the omitted parts, please refer to the foregoing embodiments; these will not be repeated in the following embodiments.

[0062] Figure 3 This is a top view and perspective view of the backlight module according to another embodiment of the present invention. Figure 3 The backlight module 10A is shown with light-emitting element 120, light-absorbing element 140A and reflective element 150, while other components of the backlight module 10A are omitted.

[0063] Figure 3 The backlight module 10A and Figure 2 The backlight module 10 is similar, the difference between the two is: Figure 3 The light-absorbing element 140A and Figure 2 The light-absorbing element 140 is different. Specifically, in Figure 2 In one embodiment, the outline of the extension 141a of the light-absorbing substrate 141 of the light-absorbing element 140 is generally elongated; however, in Figure 3 In one embodiment, the extension 141aA of the light-absorbing substrate 141A of the light-absorbing element 140 further includes an arc-shaped region 141a1 corresponding to the light-emitting element 120 and extending in a direction away from the adhesive 142. For example, in Figure 3 In one embodiment, the arc-shaped region 141a1 of the extension 141aA of the light-absorbing substrate 141A is generally a semi-circular region. However, the present invention is not limited to this, and the shape of the arc-shaped region 141a1 may change depending on the light emission distribution pattern of the light-emitting element 120; in other embodiments, the arc-shaped region 141a1 may also have other shapes.

[0064] Figure 4 This is a cross-sectional schematic diagram of a backlight module according to another embodiment of the present invention. Figure 4 The backlight module 10B and Figure 1 The backlight module 10 is similar, the difference between the two is: Figure 4 The relative positions of the adhesive material 142 and the reflective element 150 and Figure 1 The relative positions of the adhesive material 142 and the reflective element 150 are different.

[0065] Please refer to Figure 4 Specifically, in this embodiment, there is a gap g between the sidewall 150s3 of the reflective element 150 and the sidewall 142s3 of the adhesive material 142. That is, in this embodiment, the end 151 of the reflective element 150 is also the adhesive-free area NA inserted under the extension 141a, but the reflective element 150 may not be in direct contact with the adhesive material 142.

[0066] In summary, a backlight module according to an embodiment of the present invention includes a light guide element, a light-emitting element, a backplate, a light-absorbing element, and a reflective element. The light-absorbing element is disposed at least between the light-emitting element and the backplate. The light-absorbing element includes an adhesive material and a light-absorbing substrate. The adhesive material is disposed on the backplate. The light-absorbing substrate is disposed on the adhesive material and located between the light guide element and the adhesive material. Specifically, the light-absorbing substrate has an extension protruding beyond the sidewall of the adhesive material. The extension of the light-absorbing substrate, the sidewall of the adhesive material, and the backplate define a glue-free area, and the end of the reflective element is inserted into the glue-free area. Because the end of the reflective element is inserted into the glue-free area under the light-absorbing substrate, the adhesive material of the light-absorbing element is less likely to overflow from the light-absorbing substrate, and the halo effect on the light-incident side of the backlight module caused by adhesive overflow can be improved.

[0067] The above description is merely a preferred embodiment of the present invention and should not be construed as limiting the scope of the invention. Any simple equivalent changes and modifications made in accordance with the claims and specification of the present invention are still within the scope of this patent. Furthermore, no embodiment or claim of the present invention needs to achieve all the objectives, advantages, or features disclosed in the present invention. In addition, the abstract and title of the invention are only used to assist in patent document retrieval and are not intended to limit the scope of the invention. Moreover, the terms "first," "second," etc., mentioned in this specification or claims are only used to name elements or distinguish different embodiments or scopes, and are not used to limit the upper or lower limit of the number of elements.

Claims

1. A backlight module, characterized in that, The backlight module includes a light guide element, a light-emitting element, a backplate, a light-absorbing element, and a reflective element, wherein... The light guide element has a bottom surface, a light emitting surface relative to the bottom surface, and a light incident surface connecting the bottom surface and the light emitting surface; The light-emitting element is disposed next to the light-incident surface of the light-guiding element; The back plate has an accommodating space, wherein the light-emitting element and the light-guiding element are disposed in the accommodating space; The light-absorbing element is disposed at least between the light-emitting element and the back plate, wherein the light-absorbing element includes an adhesive material and a light-absorbing substrate. The adhesive material is disposed on the back plate; as well as The light-absorbing substrate is disposed on the adhesive material and located between the light guide element and the adhesive material, wherein the light-absorbing substrate has an extension protruding beyond the sidewall of the adhesive material, and the extension of the light-absorbing substrate, the sidewall of the adhesive material, and the backplate define an adhesive-free area; and The reflective element is disposed on the back plate, wherein the end of the reflective element is inserted into the adhesive-free area, and the end of the reflective element is sandwiched between the extension of the light-absorbing substrate and the bottom of the back plate.

2. The backlight module according to claim 1, characterized in that, The extension of the light-absorbing substrate is in direct contact with the reflective element.

3. The backlight module according to claim 1, characterized in that, The two opposing surfaces of the extension of the light-absorbing substrate are in direct contact with the light guide element and the reflective element, respectively.

4. The backlight module according to claim 1, characterized in that, The light-absorbing substrate has a surface facing the back plate, and the adhesive and the reflective element are in direct contact with the surface of the light-absorbing substrate.

5. The backlight module according to claim 1, characterized in that, The sidewall of the reflective element is disposed below the light-absorbing substrate and faces the sidewall of the adhesive material.

6. The backlight module according to claim 5, characterized in that, The sidewall of the reflective element is in direct contact with the sidewall of the adhesive material.

7. The backlight module according to claim 5, characterized in that, There is a gap between the sidewall of the reflective element and the sidewall of the adhesive material.

8. The backlight module according to claim 1, characterized in that, The backplate has a surface facing the bottom surface of the light guide element, and the adhesive and the reflective element are in direct contact with the surface of the backplate.

9. The backlight module according to claim 1, characterized in that, The light-absorbing substrate also has a main portion overlapping the adhesive material. The main portion and the extension portion have a first width W1 and a second width W2 respectively in a direction parallel to the light-emitting surface, and 1 / 3≤W2 / W1≤1 / 2.

10. The backlight module according to claim 1, characterized in that, The thickness of the adhesive material of the light-absorbing element is greater than or equal to the thickness of the reflective element.

11. The backlight module according to claim 1, characterized in that, The backlight module also includes flexible printed circuitry, wherein The flexible printed circuit is electrically connected to the light-emitting element, wherein the light-guiding element is disposed between the flexible printed circuit and the light-absorbing substrate.

12. The backlight module according to claim 11, characterized in that, A portion of the flexible printed circuit overlaps the adhesive-free area.

13. The backlight module according to claim 1, characterized in that, The extension of the light-absorbing substrate includes an arc-shaped region corresponding to the light-emitting element.

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