Backlight module and display apparatus

Abstract

A backlight module, comprising: a backplate, a light source unit, a middle frame, and a front frame. The backplate has a plurality of side walls together forming an accommodating space, and a gap is formed between two adjacent side walls. The light source unit is located within the accommodating space. The middle frame has at least one positioning protrusion extending to the gap, such that the middle frame is restricted in position relative to the backplate. The front frame covers the side walls and the at least one positioning protrusion. The gap of the backplate can be used as a mounting and positioning structure of the middle frame, and at the same time, reduces backlight module light leakage.

Description

Backlight module and display device Technical Field

[0001] This invention relates to a backlight module, and more precisely, to a backlight module that facilitates mid-frame assembly and positioning and prevents light leakage, and a display device comprising the same. Background Technology

[0002] Please refer to Figure 1. The components of the backlight module in the display panel are all installed in the metal back plate of the backlight module. The back plate 20A has a base plate and side walls. It is formed by stamping and bending during the sheet metal process, so a gap 25A will be generated between adjacent side walls. After the internal components of the backlight module are assembled, a front frame 10A will be assembled onto the back plate 20A. The front frame 10A and the side walls of the back plate 20A are provided with a matching structure. Therefore, the gap 25A between adjacent side walls of the back plate 20A is also to keep the side walls flexible.

[0003] As a schematic diagram of the aforementioned installation structure, the light source unit 30A is mounted on the bottom plate of the back panel 20A and surrounded by the middle frame 40A. When the light from the light source unit 30A is projected toward the front frame 10A, it will pass through the optical assembly 50A (such as the optical film 51A and diffuser 52A in the icon). However, after passing through the optical film, some light may escape toward the surface of its edge and then be projected downward through the gap between the side walls (as indicated by the dashed arrow in Figure 1), causing light leakage. Summary of the Invention

[0004] This invention provides a backlight module comprising: a back panel, a light source unit, a middle frame, and a front frame. The back panel has multiple sidewalls forming an accommodating space, with a gap between two adjacent sidewalls. The light source unit is located within the accommodating space. The middle frame has at least one positioning protrusion extending into the gap to confine it to the back panel. The front frame covers the sidewalls and the at least one positioning protrusion.

[0005] In this way, the gap between the side walls of the back panel can serve as the installation and positioning structure for the middle frame, while the positioning protrusions of the middle frame can be used to reduce light leakage from the backlight module.

[0006] In some embodiments, the back panel further includes a connecting portion that connects the two adjacent sidewalls, and the positioning protrusions rest on the connecting portion.

[0007] In some embodiments, the thickness of these positioning protrusions protruding outward from the back plate is substantially the same as the thickness of the sidewall.

[0008] In some embodiments, the middle frame forms a reflective structure located within the accommodating space and disposed on the light source unit.

[0009] In some embodiments, the backlight module is a direct-lit backlight module, the reflective structure has multiple perforations, the light source unit has a lamp board and multiple light sources arranged in a matrix on the lamp board, and the light sources pass through the perforations respectively.

[0010] In some embodiments, an optical assembly is also included, which is located between the middle frame and the front frame.

[0011] In some embodiments, the optical assembly is surrounded by the sidewall.

[0012] In some embodiments, the positioning protrusions have an upper end face, and the middle frame has an upper surface for supporting the optical assembly. The upper end face of the positioning protrusions is higher than the upper surface of the middle frame to cover the corners of the optical assembly.

[0013] In some embodiments, the upper end face of these positioning protrusions is located on the same plane as the upper surface of the optical assembly.

[0014] The present invention also provides a display device comprising: the aforementioned backlight module; and a display panel located above the backlight module. Attached Figure Description

[0015] Figure 1 is a cross-sectional view of an existing backlight module.

[0016] Figure 2 shows the appearance of the backlight module.

[0017] Figure 3 is an exploded view of the components of one embodiment of the backlight module.

[0018] Figure 4 is a partial enlarged view of the middle frame and back plate of the embodiment in Figure 3.

[0019] Figure 5 is a cross-sectional view of the backlight module of the embodiment in Figure 3.

[0020] Figure 6 is a partial enlarged view of the middle frame and back panel of another embodiment.

[0021] Figure 7 is a cross-sectional view of the backlight module of the embodiment in Figure 6. Detailed Implementation

[0022] The directional descriptions described below are based on the light emission direction of the backlight module as upwards, in order to conform to the common understanding of those skilled in the art.

[0023] Please refer to Figures 2 to 5, which illustrate a backlight module of one embodiment, including a backplate 20, a light source unit 30, a middle frame 40, and a front frame 10. The backplate 20 has multiple sidewalls 22 forming an accommodating space, with a gap 25 formed between two adjacent sidewalls 22. The light source unit 30 is located within the accommodating space. The middle frame 40 has at least one positioning protrusion 41 extending to the gap 25 to confine it to the backplate 20. The front frame 10 covers the sidewalls 22 and the at least one positioning protrusion 41. This invention utilizes the gap 25 formed by the sidewalls 22 of the backplate 20, and precisely positions and fixes it to the backplate 20 by means of the positioning protrusion 41 on the middle frame 40. This design effectively simplifies the structure of the backlight module, reduces assembly steps, lowers assembly difficulty, and improves assembly efficiency and product reliability. Thus, the gap 25 between the side walls of the back panel 20 can serve as the installation and positioning structure for the middle frame, while the positioning protrusions of the middle frame can be used to solve the problem of light leakage.

[0024] In one embodiment, as shown in Figures 2 to 5, the back plate 20 has a base plate 21 and a plurality of side walls 22 connected to the base plate 21. The back plate 20 has two pairs of mutually perpendicular side walls 22, and the base plate 21 and these side walls 22 together form the receiving space. The middle frame 40 has a ring side wall 402, the extension direction of which is the same as that of the side wall 22 of the back plate 20. The middle frame 40 is positioned in the receiving space, disposed above the light source unit 30, such that the ring side wall 402 surrounds the light source unit 30.

[0025] In one embodiment, as shown in Figures 2 to 5, an optical assembly 50 is further included. The optical assembly 50 is located between the middle frame 40 and the front frame 10. The upper surface 401 of the middle frame 40 is used to support the optical assembly 50 (including but not limited to the optical film 51 and the diffuser 52), or to further limit the optical assembly 50 so that the optical assembly 50 is located above the light source unit 30. In another embodiment, the optical assembly 50 may also be surrounded by the sidewall 22, which effectively prevents interference from external light and provides a limiting effect on the optical assembly 50.

[0026] The front frame 10 has a ring sidewall 11 and an upper edge. The ring sidewall 11 and the sidewall 22 of the back plate 20 are provided with a concave-convex matching structure to engage, so that the front frame 10 is installed on the back plate 20 from top to bottom. The upper edge of the front frame 10 forms an opening, and the boundary of the opening is located above the optical assembly 50. In other words, the edge of the optical assembly 50 is located between the lower surface 102 of the upper edge and the upper surface 401 of the middle frame 40. In this way, the optical assembly 50 is effectively contained.

[0027] In one embodiment, as shown in Figures 2 to 5, the middle frame 40 has at least one positioning protrusion 41 located at the corner of the annular sidewall 402. The position of the positioning protrusion 41 corresponds to the gap between the two adjacent sidewalls 22 of the front frame 10. When the middle frame 40 is mounted on the back plate 20, the positioning protrusion 41 extends towards the gap 25 relative to the annular sidewall 402, thus confining the middle frame 40 to the back plate 20. The front frame 10 then covers the sidewall 22 and the at least one positioning protrusion 41. In this way, the at least one positioning protrusion 41 serves not only as a positioning means for the middle frame 40 to be mounted on the back plate 20, but also as a means to prevent internal light from being projected out through the gap 25.

[0028] In one embodiment, as shown in Figures 2 to 5, the back plate 20 further includes a connecting portion 26, which connects between the two adjacent sidewalls 22. The positioning protrusions 41 rest on the connecting portion 26. Furthermore, these positioning protrusions 41 can also contact the sidewall 22 at the gap 25 to form a side end face 222, ensuring that the middle frame 40 does not wobble horizontally when assembled to the back plate 20. More preferably, the connecting portion 26 extends from the base plate 21 and connects between the two adjacent sidewalls 22, thus further enhancing the stability of the structure and preventing displacement during assembly or use from affecting optical performance.

[0029] In one embodiment, as shown in Figures 2 to 5, the number of these positioning protrusions 41 is the same as the number of gaps 25. The thickness of these positioning protrusions 41 protruding outward from the back plate 20 is substantially the same as the thickness of the side wall 22. This simplifies the manufacturing process and reduces material costs. Furthermore, by using these positioning protrusions 41 of the middle frame 40 to position the middle frame 40 from the corner of the annular side wall 402 at the gap 25, when the middle frame 40 is mounted on the back plate 20, at the position of the gap 25, the projected outline of the back plate 20 in the vertical direction at the connecting portion 26 can overlap with the projected outline of the arcuate outer surface 412 of the positioning protrusion 41 (as shown in Figure 6) at the same position. In this way, even if the upper surface of the positioning protrusion 41 is on the same plane as the upper surface 401 of other positions of the middle frame 40, it can be ensured that light does not project downward from the gap 25.

[0030] In one embodiment, as shown in Figures 2 to 5, the light source unit 30 includes a lamp panel 31 and a plurality of light sources 32 arranged in a matrix on the lamp panel 31. The bottom of the lamp panel 31 has a cylinder to position the light source unit 30 within a circular perforation in the bottom plate 21 of the back plate 20, thus forming a direct-lit backlight module. The matrix arrangement of the plurality of light sources 32 ensures the consistency of the light source.

[0031] In one embodiment, as shown in Figures 2 to 5, the mid-frame constructs a reflective structure 42, which is located within the accommodating space and disposed on the light source unit 30. In this way, the direct-lit backlight module can precisely control the transmission direction of light, further improving light utilization and avoiding multiple reflections within the reflective structure 42 that could cause light confusion and reduce optical quality. Through precise structural design, this invention effectively controls the light transmission path, reduces light scattering and interference, thereby improving the brightness, uniformity, and color saturation of the displayed image. More preferably, the reflective surface 422 of the mid-frame 40 constructs multiple cone-shaped reflective structures 42. The reflective structure 42 has multiple perforations 421 through which multiple light sources 32 of the light source unit 30 pass. The reflective structure surrounds the light source 32, which facilitates the reflection of light emitted from the light source 32 towards the light-emitting direction by the reflective structure of the reflective surface 422, thus reducing light scattering and loss and significantly improving light utilization efficiency. However, in other embodiments, the backlight module can also be a side-lit backlight module.

[0032] Please refer to Figures 6 and 7, which illustrate another embodiment of the backlight module. The difference from the previous embodiment is that the upper end face 411 of these positioning protrusions 41 is higher than the upper surface 401 of the middle frame 40 used to support the optical assembly 50, thus covering the corners of the optical assembly 50. Preferably, these positioning protrusions 41 have a complete arcuate profile and protrude upwards. Accordingly, the positioning protrusions 41 can directly block light projected laterally from the edge surface of the optical assembly 50, effectively protect the corners of the optical assembly 50 from damage, ensure the stability of the optical assembly 50, and further improve display quality.

[0033] In one embodiment, as shown in Figures 6 and 7, the upper end faces 411 of these positioning protrusions 41 are at least on the same plane as the upper surface of the optical assembly 50, or the upper end faces 411 of these positioning protrusions 41 are flush with the upper end face 221 of the sidewall 22, or the upper end faces 411 of these positioning protrusions 41 can be designed to contact the lower surface 102 of the upper edge of the front frame 10. Furthermore, the contour of the arcuate outer surface 412 of these positioning protrusions 41 is the same as the contour of the inner surface of the front frame 10, directly preventing internal light from entering the gap 25. In addition, the design of the upper end faces 411 of the positioning protrusions 41 being on the same plane as or higher than the upper surface 401 of the middle frame 40 effectively protects the corners of the optical assembly 50, avoids damage to the optical assembly 50, ensures the stability of the optical assembly 50, and further improves the display quality.

[0034] The present invention also provides a display device comprising the aforementioned backlight module and a display panel 70 located above the backlight module. The display panel 70 is supported by the upper surface 101 of the upper edge of the front frame 10. Light from the plurality of light sources 32 is projected through the optical assembly 50 and illuminates the rear of the display panel 70 through an opening at the upper edge of the front frame 10. The backlight module of the present invention has a simple design and compact structure, and is suitable for display devices of various sizes and specifications, such as mobile phones, tablet computers, and laptops. Its excellent optical performance and high reliability give it broad application prospects and can effectively enhance the competitiveness of products.

[0035] In the backlight module disclosed in this invention, the gap between the sidewalls of the back plate can serve as the mounting and positioning structure for the middle frame. At the same time, the positioning protrusions of the middle frame reduce light leakage of the backlight module. Furthermore, the simple structural design between the positioning protrusions of the middle frame and the sidewalls of the back plate not only achieves better structural stability and assembly convenience, but also ensures optical quality / appearance optimization, and further improves the yield after challenge testing.

[0036]

Symbol Explanation

Claims

1. A backlight module, comprising: The back panel has multiple side walls that together form an accommodating space, with a gap between two adjacent side walls; The light source unit is located within this accommodating space; The middle frame has at least one positioning protrusion extending into the gap to limit its position within the back panel; as well as The front frame covers the side wall and the at least one positioning protrusion.

2. The backlight module as claimed in claim 1, wherein the back plate further includes a connecting portion connected between the two adjacent sidewalls, and the positioning protrusions rest on the connecting portion.

3. The backlight module as claimed in claim 1, wherein the thickness of the positioning protrusions protruding outward from the back plate is substantially the same as the thickness of the sidewall.

4. The backlight module as claimed in claim 1, wherein the middle frame forms a reflective structure, the reflective structure being located within the accommodating space and disposed on the light source unit.

5. The backlight module as described in claim 4, wherein the backlight module is a direct-lit backlight module, the reflective structure has a plurality of perforations, the light source unit has a lamp board and a plurality of light sources arranged in a matrix on the lamp board, and the light sources pass through the perforations respectively.

6. The backlight module of claim 1, further comprising an optical assembly located between the middle frame and the front frame.

7. The backlight module of claim 6, wherein the optical assembly is surrounded by the sidewall.

8. The backlight module of claim 6, wherein the positioning protrusions have an upper end face, the middle frame has an upper surface for supporting the optical assembly, and the upper end face of the positioning protrusions is higher than the upper surface of the middle frame to cover the corners of the optical assembly.

9. The backlight module of claim 6, wherein the upper end faces of the positioning protrusions are located on the same plane as the upper surface of the optical assembly.

10. A display device comprising: a backlight module as claimed in any one of claims 1 to 9; and a display panel located above the backlight module.

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