Backlight module and display device

Abstract

The present disclosure relates to a backlight module for providing a light source to a display panel, comprising: a back plate comprising a bottom plate and a side plate surrounding a periphery of the bottom plate; a middle frame comprising a first part and a second part, the first part being arranged around the periphery of the bottom plate, the second part being arranged at an end of the first part away from the bottom plate, a transmittance of the second part being greater than or equal to 90%. The present disclosure also relates to a display device.

Description

Backlight module and display device Technical Field

[0001] This disclosure relates to the field of display product manufacturing technology, and in particular to a backlight module and display device. Background Technology

[0002] With the development of splicing display technology, the market has higher requirements for image quality. Improving the edge dark frame and enhancing the uniformity of the surrounding image quality have become crucial. Currently, an integrated middle frame is used to support the diffuser plate. The middle frame is an opaque structure, which will cause the product edges to appear dark, affecting the overall image quality.

[0003] Summary of the Invention

[0004] To address the aforementioned technical problems, this disclosure provides a backlight module and a display device that solve the problem of poor edge image quality.

[0005] To achieve the above objectives, the technical solution adopted in this disclosure is: a backlight module for providing a light source to a display panel, comprising:

[0006] The back panel includes a bottom panel and side panels surrounding the bottom panel;

[0007] The middle frame includes a first part and a second part. The first part is arranged around the perimeter of the base plate, and the second part is arranged at the end of the first part away from the base plate. The transmittance of the second part is greater than or equal to 90%.

[0008] Optionally, the first part includes a first inclined surface and a first connecting surface for connecting the second part, wherein the connection between the first inclined surface and the first connecting surface is constructed as a first arc surface;

[0009] The second part includes a second connecting surface connected to the first connecting surface, a second arc surface connected to the first arc surface, and a second inclined surface with one end connected to the second arc surface, the second inclined surface extending away from the base plate.

[0010] Optionally, in the direction perpendicular to the base plate, the cross-sectional shape of the second part is trapezoidal, the first part includes a first connecting surface for connecting with the second part, the second part includes a third connecting surface for connecting with the first connecting surface, and the end of the third connecting surface away from the side plate is exposed outside the first connecting surface.

[0011] Optionally, a diffusion plate is also included, with an adhesive layer disposed between the second part and the diffusion plate.

[0012] Optionally, the second part is a single integral structure, or in the circumferential direction of the first part, the second part includes a plurality of transparent sub-parts spaced apart.

[0013] Optionally, in the circumferential direction of the first part, the total length D of the second part satisfies the following formula: D≥(0.16~0.26)*G.

[0014] Optionally, the haze of the second part is 30% to 50%.

[0015] Optionally, the first part has a protrusion at the end away from the base plate, and the second part has a groove at the end near the first part. The groove and the protrusion cooperate to allow the first part and the second part to be inserted together.

[0016] Optionally, in a direction perpendicular to the base plate, the cross-sectional shape of the end of the first portion away from the base plate is configured as an L-shaped structure, and the second portion is connected to the L-shaped structure on the side near the center of the back plate.

[0017] The L-shaped structure includes a first side and a second side arranged perpendicularly to each other. The second side is arranged parallel to the base plate. The protrusion includes a fourth connecting surface connected to the first side and a fifth connecting surface connected to the second side.

[0018] In a direction away from the first side, the protrusion includes a limiting portion that limits the second part.

[0019] Optionally, in the direction away from the first side, the protrusion includes a first connecting portion and a second connecting portion, the first connecting portion and the second connecting portion having a T-shaped structure, the side of the first connecting portion away from the second connecting portion being the fourth connecting surface, and the second connecting portion being the limiting portion.

[0020] Optionally, it also includes a frame surrounding the periphery of the back panel, the frame including a side frame located around the periphery of the side panel, and the maximum distance between the inner side of the middle frame and the frame in a direction parallel to the bottom plate is 6.5-7mm.

[0021] Optionally, a portion of the outer side of the frame is recessed to form a recess, a first screw hole is provided in the recess, and a second screw hole is provided on the side plate to cooperate with the first screw hole for screws to pass through. The size of the recess gradually increases along the direction away from the base plate.

[0022] Optionally, the maximum distance between the first screw hole and the end face of the frame away from the base plate is 10mm, and the maximum height of the second part in the direction perpendicular to the base plate is 7mm.

[0023] This disclosure also provides a display device including the backlight module described above.

[0024] The beneficial effects of this disclosure are: the backlight module provided by this disclosure includes a back plate and a middle frame. The back plate includes a bottom plate and side plates surrounding the bottom plate. The middle frame is split. The middle frame includes a first part surrounding the bottom plate and a second part located at the end of the first part away from the bottom plate. The transmittance of the second part is greater than or equal to 90%, which increases the amount of light entering the edge area and improves the edge light effect. Attached Figure Description

[0025] Figure 1 shows a schematic diagram of a backlight module in the related technology;

[0026] Figure 2 shows a schematic diagram of the optical path of the backlight module in the related technology;

[0027] Figure 3 shows a schematic diagram of the optical path at the Rib structure;

[0028] Figure 4 shows a schematic diagram of the backlight module in an embodiment of this disclosure;

[0029] Figure 5 shows a schematic diagram of the optical path of the backlight module in an embodiment of this disclosure;

[0030] Figure 6 shows an exploded view of the first and second parts of the middle frame;

[0031] Figure 7 shows a schematic diagram of the optical path in the second part, which uses an arc-shaped bird's beak.

[0032] Figure 8 shows a schematic diagram of the lighting effect in the second part, which uses an arc-shaped bird's beak.

[0033] Figure 9 shows a schematic diagram of the second part adopting a trapezoidal shape;

[0034] Figure 10 shows a schematic diagram of the brightness curve simulation results;

[0035] Figure 11 shows a schematic diagram of the simulated screen;

[0036] Figure 12 shows a schematic diagram of the simulated screen;

[0037] Figure 13 shows a schematic diagram of the simulated screen;

[0038] Figure 14 shows a schematic diagram of the second part;

[0039] Figure 15 shows a schematic diagram of the second part;

[0040] Figure 16 shows a schematic diagram of the second part;

[0041] Figure 17 shows a schematic diagram of total internal reflection occurring inside the second part;

[0042] Figure 18 shows a schematic diagram of the light within the second part where the fog level is set;

[0043] Figure 19 shows a schematic diagram of brightness curves for different levels of haze;

[0044] Figure 20 shows a schematic diagram of a simulated scene with 10% fog.

[0045] Figure 21 shows a schematic diagram of a simulated scene with 30% fog.

[0046] Figure 22 shows a schematic diagram of a simulated scene with 50% fog.

[0047] Figure 23 shows a schematic diagram of a simulated scene with 65% fog.

[0048] Figure 24 shows a schematic diagram of the protrusion;

[0049] Figure 25 shows a schematic diagram of the protrusion;

[0050] Figure 26 shows a schematic diagram of the protrusion;

[0051] Figure 27 shows a schematic diagram of the protrusion;

[0052] Figure 28 shows a schematic diagram of the distribution of the protrusions;

[0053] Figure 29 shows a schematic diagram of the backlight module;

[0054] Figure 30 shows a schematic diagram of the backlight module;

[0055] Figure 31 shows a schematic diagram where the light is not blocked by the protrusion;

[0056] Figure 32 shows a schematic diagram of light being blocked by a protrusion;

[0057] Figure 33 shows a schematic diagram of the simulated scene;

[0058] Figure 34 shows a schematic diagram of the brightness curve simulation;

[0059] Figure 35 shows a schematic diagram of the simulated screen;

[0060] Figure 36 shows a schematic diagram of the brightness curve simulation;

[0061] Figure 37 shows a comparative diagram of the positions of the first screw holes;

[0062] Figure 38 shows a schematic diagram of the brightness curve simulation. Detailed Implementation

[0063] To make the objectives, technical solutions, and advantages of the embodiments of this disclosure clearer, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. All other embodiments obtained by those skilled in the art based on the described embodiments of this disclosure without creative effort are within the scope of protection of this disclosure.

[0064] Unless otherwise defined, the technical or scientific terms used in this disclosure shall have the ordinary meaning understood by one of ordinary skill in the art to which this disclosure pertains. The terms “first,” “second,” and similar terms used in this disclosure do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Similarly, the terms “an,” “a,” or “the,” and similar terms do not indicate a quantity limitation, but rather indicate the presence of at least one. The terms “including,” “comprising,” or “containing,” and similar terms mean that the element or object preceding the word encompasses the elements or objects listed following the word and their equivalents, without excluding other elements or objects. The terms “connected,” “linked,” or similar terms are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. The terms “upper,” “lower,” “left,” and “right,” etc., are used only to indicate relative positional relationships, and these relative positional relationships may change accordingly when the absolute position of the described objects changes.

[0065] The features such as "parallel," "perpendicular," and "identical" used in the embodiments of this disclosure include features in the strict sense of "parallel," "perpendicular," and "identical," as well as cases where "approximately parallel," "approximately perpendicular," and "approximately identical" include certain tolerances. Taking into account the measurement and the tolerances associated with the measurement of a specific quantity (e.g., limitations of the measurement system), they represent the acceptable deviation range for a specific value as determined by a person skilled in the art. For example, "approximately" can mean within one or more standard deviations, or within 3% or 5% of said value.

[0066] With the development of splicing display technology, the market has higher requirements for image quality, making the improvement of edge dark frames and the enhancement of the uniformity of surrounding image quality crucial.

[0067] Referring to Figures 1-3, to address the aforementioned issues, multiple support portions 4 are provided at the top of the middle frame. These multiple support portions 4 are spaced apart along the circumferential direction of the middle frame. The arrangement of multiple support portions 4 reduces the contact area with the diffuser plate, thereby increasing the amount of light entering the edge.

[0068] Referring to Figures 4-38, in order to improve edge image quality, some embodiments specifically provide a backlight module for providing a light source to the display panel 10, including:

[0069] The back plate 1 includes a bottom plate 11 and side plates 12 surrounding the bottom plate 11.

[0070] The middle frame 2 includes a first part 21 and a second part 22. The first part 21 is arranged around the perimeter of the base plate 11, and the second part 22 is arranged at the end of the first part 21 away from the base plate 11. The transmittance of the second part 22 is greater than or equal to 90%.

[0071] In this embodiment, the backlight module has a light source mounted on the base plate 11 of the back panel 1. The middle frame 2 has a split structure, including a first part 21 surrounding the base plate 11 and a second part 22 located at the end of the first part 21 away from the base plate 11. The second part 22 has a transparent structure with a transmittance greater than or equal to 90%, allowing the light emitted by the light source to pass through the second part 22 and reach the edge of the optical structure supported by the middle frame 2, increasing the amount of light entering the edge area, improving the edge light effect, preventing the corresponding edge area of ​​the display panel 10 from darkening, and improving the display effect.

[0072] Since the transmittance of the second part 22 is greater than or equal to 90%, the edge image quality is improved compared to the Rib structure, which suffers from the problem of Rib shadows. In this embodiment, the middle frame 2 adopts the second part 22 with a transmittance of greater than or equal to 90%, which effectively avoids the problem of no light in the overlapping area between the diffuser plate 3 and the middle frame 2. In addition, the second part 22 increases the amount of light entering the edge area and improves the edge lighting effect. Comparing Figure 2 and Figure 5, the structure shown in Figure 2 has a limited overall inner wall slope angle, resulting in limited light intensity for both direct entry and reflected entry. The structure shown in Figure 5 provided by this disclosure greatly increases the edge light-entry area, avoiding the difficulty of light being blocked due to the slope angle. Light passes through the second part 22 and directly enters the edge area, resulting in a significant improvement in lighting effect.

[0073] The second part 22 can have various specific structural forms. The following describes two structural forms in the embodiments of this disclosure:

[0074] First structural form: Referring to Figures 4-8, in an exemplary embodiment, the first part 21 includes a first inclined surface 211 and a first connecting surface 213 for connecting the second part 22, and the connection between the first inclined surface 211 and the first connecting surface 213 is constructed as a first arc surface 214.

[0075] The second part 22 includes a second connecting surface 222 connected to the first connecting surface 213, a second arc surface 223 connected to the first arc surface 214, and a second inclined surface 224 connected at one end to the second arc surface 223, the second inclined surface 224 extending away from the base plate 11.

[0076] Using the above scheme, the second part 22 has an arc-shaped beak structure, allowing more light to enter from the second part 22 and increasing the luminous flux in the edge area. The first arc surface 214 and the second arc surface 223 cooperate to increase the opening area (i.e., the area of ​​the light incident surface of the second part 22, i.e., the area of ​​the second inclined surface 224). The edge tangent of the first arc surface 214 or the second arc surface 223 is the light limit incident angle (refer to the light ray 100° in Figure 7). Compared with the first inclined surface 211 and the first connecting surface 213 being constructed as a right angle, the incident area of ​​the lower light is increased. Secondly, the first arc surface 214 is a convex structure that protrudes away from the back plate 1, which has the effect of scattering the light incident on the first arc surface 214. Referring to Figure 10, this makes the light more uniform and avoids the bright lines or dark edges on the screen caused by the single-angle reflection of light by the straight edge chamfer structure.

[0077] The second structural form: Referring to Figure 9, in an exemplary embodiment, in the direction perpendicular to the base plate 11 (refer to the Y direction in Figure 4), the cross-sectional shape of the second part 22 is trapezoidal. The first part 21 includes a first connecting surface 213 for connecting with the second part 22, and the second part 22 includes a third connecting surface for connecting with the first connecting surface 213. The end of the third connecting surface away from the side plate 12 is exposed outside the first connecting surface 213.

[0078] In the direction perpendicular to the base plate 11, the cross-sectional shape of the second portion 22 is trapezoidal, and in the direction perpendicular to the side plate 12, the length of the side of the second portion 22 away from the base plate 11 is less than the length of the third connecting surface. The end of the third connecting surface away from the side plate 12 is exposed beyond the first connecting surface 213. That is, on the side away from the side plate 12, the second portion 22 extends beyond the first portion 21, increasing the amount of light entering the edge area and enhancing the edge lighting effect. The light emitted by the light source located on the base plate 11 is not blocked by the first portion 21 of the middle frame 2; the light enters the edge area through the portion of the second portion 22 that extends beyond the first portion 21, thereby improving edge brightness.

[0079] The second part 22 adopts the first and second structural forms mentioned above, both of which increase the amount of light entering the edge region and improve the light efficiency of the edge region. In order to ensure the authenticity and practical applicability of the simulation model parameters, optical image simulation and simulation of actual edge brightness curves were performed on the schemes shown in Figures 4-9 and Figures 1-3. The comparison results are shown in Figures 10-13. In Figure 10, curve 1001 is the simulation curve of the scheme shown in Figures 1-3, curve 1002 is the measured curve of the scheme shown in Figures 1-3, curve 1003 is the simulation curve of the second structural form, and curve 1004 is the simulation curve of the first structural form. The horizontal axis in Figure 10 represents the distance to the edge of the screen (0mm represents the edge of the screen); the vertical axis in Figure 10 represents the relative brightness ratio, and 1 is the brightness of the module center (the specific brightness varies depending on the product specifications and is not limited). Taking this product as an example, the brightness of the module center is 520-550 nits. The horizontal axis in Figures 11-13 is the distance to the edge of the screen (0mm represents the edge of the screen). Figures 11-13 are partial schematic diagrams taken from the entire display screen, and the partial schematic diagrams include the edge represented by 0mm. Figure 11 is a schematic diagram of the simulated screen of the scheme shown in Figures 1-3, and Figure 11 is a simulated display screen based on the brightness curve 1001 in Figure 10. Combining Figures 10 and 11, it can be seen that the brightness of the scheme shown in Figures 1-3 reaches the peak brightness at a position of 15mm from the edge, and the dark area is the area from 0 to 15mm from the edge. Figure 12 is a schematic diagram of a simulated screen of the second part 22 using the first structural form in this embodiment. Figure 12 is also a simulated display screen based on the brightness curve 1004 in Figure 10. Combining Figures 10 and 12, it can be seen that when the second part 22 uses the first structural form, the brightness reaches its peak at a position 10mm from the edge, and the brightness decay range (dark area) is 0-10mm. Figure 13 is a schematic diagram of a simulated screen of the second part 22 using the second structural form in this embodiment. Figure 11 is a simulated display screen based on the brightness curve 1003 in Figure 10. Combining Figures 10 and 13, it can be seen that when the second part 22 uses the second structural form, the brightness reaches its peak at a position 10mm from the edge, and the brightness decay range (dark area) is 0-10mm. First, it is confirmed that the simulation results of the schemes shown in Figures 1-3 are basically the same as the measured results (compare brightness curves 1001 and 1002). The edge brightness at a distance of 5mm is generally used as the criterion for judging edge image quality. The brightness at a distance of 5mm from the edge decreases by about 90%, which proves that the simulation model is built accurately.Secondly, the simulated image of the schemes shown in Figures 4-9 is superior, with better uniformity than the current products. The brightness curve at 5mm from the edge reaches 95% (where the second part 22 adopts the second structural form, the edge brightness at 5mm is about 97%; the second part 22 adopts the first structural form, the edge brightness at 5mm is 95%, and the brightness curve attenuation is good; while the schemes shown in Figures 1-3 have a brightness of only 90% at 5mm, which is relatively poor), and the edge image quality is significantly improved, with good results.

[0080] Comparing the second part 22 using the first structural form and the second structural form described above: the edge brightness curve corresponding to the second part 22 using the second structural form is better than the edge brightness curve corresponding to the second part 22 using the first structural form described above, and the edge light effect is increased more.

[0081] In an exemplary embodiment, the backlight module further includes a diffuser plate 3. The diffuser plate 3 is mainly used to mix the light emitted by the light source, so that the light is emitted uniformly and the brightness uniformity is improved. In this embodiment, the back plate 1 is made of SECC (electro-galvanized steel sheet), SGCC (hot-dip galvanized steel sheet), etc., and the middle frame 2 can be made of PC (polycarbonate). The middle frame 2 and the back plate 1 cooperate to support the diffuser plate 3 and the display panel 10.

[0082] In an exemplary embodiment, an adhesive layer 6 is provided between the second part 22 and the diffuser plate 3. This improves the connection stability of the diffuser plate 3, effectively solves the risk of the diffuser plate 3 falling off due to the use of a Rib structure to support the diffuser plate 3, and also solves the problem of uneven image quality around the diffuser plate 3 caused by its misalignment.

[0083] The adhesive layer 6 can be double-sided tape, but is not limited to this.

[0084] In an exemplary embodiment, the second part 22 is an integral structure, or in the circumferential direction of the first part 21, the second part 22 includes a plurality of transparent sub-parts spaced apart, as shown in FIG16.

[0085] In embodiments where the overall frame 2 is rectangular, the second part 22 can be four strip structures corresponding to the four sides of the rectangle, facilitating installation. In some embodiments, corresponding to each side of the rectangle, the second part 22 can include multiple transparent sub-parts spaced apart. Figure 15 only shows the transparent sub-parts on one long side and one short side. Although not shown on the other long side and the other short side, it should be understood that transparent sub-parts are provided thereon.

[0086] When the second part 22 includes multiple transparent sub-parts spaced apart, it is necessary to ensure that the length of the middle frame 2 supporting the diffuser plate 3 is sufficient to completely fix the diffuser plate 3, while also reducing material usage and lowering costs. Therefore, this embodiment establishes a mathematical model for the fixed area of ​​the diffuser plate 3.

[0087] The diffusion plate 3 has a thickness of 1.5t and a weight of 1.5kg. The double-sided adhesive used to fix the diffusion plate 3 (i.e., the adhesive layer 6) has a thickness of 0.2t and a viscosity of k = 15N / inch. In the circumferential direction of the first part 21, in order to ensure that the double-sided adhesive on the middle frame 2 and the diffusion plate 3 have sufficient bonding length to provide sufficient adhesive force to fix the diffusion plate 3, the limit value for fixing the diffusion plate 3 is defined as the diffusion plate 3 not falling off due to its own weight. From the formula, the adhesive force F = k * D * R ≥ S N *G, and obtain: Where G is the weight of the diffuser plate 3, D is the total length of the second part 22 in the circumferential direction of the first part 21, R is the adhesion coefficient, and S... N This is for the safety factor.

[0088] In the above formula, R is the adhesion coefficient. Because the double-sided tape uses solid pressure-sensitive adhesive, the adhesion coefficient varies for substrates with different roughnesses. The adhesion coefficients are shown in Table 1. Generally, the roughness R... a 0.4~R a 1.6 is for finely processed, smooth bonding surfaces. Excessive smoothness or roughness will reduce bonding strength. The PC material frame has a smooth surface, and the roughness R of the double-sided adhesive is... 胶 =1, the roughness of diffuser plate 3 is relatively high, R 扩 =0.5~0.6.

[0089] Table 1

[0090] In the above formula, S N The safety factor reflects the degree of safety in structural design and represents the feasibility of a theoretical model in actual production. In general engineering structural applications, S... N Between 1.5 and 2.0.

[0091] In summary, based on theoretical calculations, we can conclude that: D(inch) ≥ (0.16~0.26)*G.

[0092] Substituting the data from this embodiment (the weight of the diffuser plate 3 is 1.5 kg) into the above mathematical model formula, we obtain that the total length D of the second part 22 in the circumferential direction of the first part 21 is ≥ 97.5 mm.

[0093] In the embodiment where the entire middle frame 2 is rectangular, a cost-effective design is adopted. The second part 22 includes four transparent sub-parts corresponding to the four sides of the rectangle. Under the premise of meeting the fixing requirements of the diffuser plate 3, the second part 22 and the diffuser plate 3 adopt the shortest total bonding length, that is, the second part 22 adopts the shortest total length. The specific scheme is shown in Figure 16. The total length D of the second part 22 is 100mm, the length of the transparent sub-part corresponding to each long side of the rectangle is 30mm, and the length of the transparent sub-part corresponding to each short side of the rectangle is 20mm.

[0094] In this disclosure, the middle frame 2 includes a first part 21 and a second part 22, and the transmittance of the second part 22 is greater than or equal to 90%. In some embodiments, based on this, the second part 22 is given a haze setting to improve the uniformity of the image. First, in this disclosure, the transmittance of the second part 22 of the middle frame 2 is greater than or equal to 90%. The second part 22 can be made of transparent PC material to achieve the corresponding transmittance. Because the second part 22 made of transparent PC material is a different medium layer from the air, light perpendicular to the side plate 12 of the back plate 1 will undergo total internal reflection in the second part 22, as shown in Figure 17. The light entering the second part 22 will be further utilized, so the edge brightness is particularly significantly improved. The backlight module provided in this disclosure achieves an edge brightness of over 95% at 5mm (i.e., 5mm away from the edge of the product). Based on actual product experience and client standards, it is generally considered that the edge image quality is good when the edge brightness curve attenuates to over 90% at 5mm. Therefore, in this embodiment, an inorganic LED light diffusing agent (nano-barium sulfate, silicon dioxide) is added to the second part 22. The diffusing agent is generally a micron-sized chemical particle, which, from a microscopic perspective, can act as countless solid microspheres to continuously refract, scatter, and reflect light, thereby achieving the effect of light mixing. This transforms the point light source or line light source originally emitted from the second part 22 into a surface light source, resulting in a softer and more uniform overall image without bright edges or dark bands. The overall solution is shown in Figure 18. By appropriately reducing the edge brightness while ensuring good edge image quality, the uniformity of the surrounding image is improved, which not only meets the requirements for edge image quality but also enhances the uniformity of the surrounding image quality.

[0095] Because the particles in the diffusing agent are solid microparticles, the transmittance of light is reduced, and the refraction and reflection of light are increased. Therefore, the concentration parameter of the diffusing agent is haze. Figures 19-23 show the simulated actual edge brightness curves and visual effects of different concentrations of diffusing agent (haze 10%, 30%, 50%, 65%). In Figure 19, curve 1006 represents the brightness curve when the haze is 30%, and curve 1005 represents the brightness curve when the haze is 50%. (The horizontal axis in Figure 19 represents the distance to the edge of the screen (0mm represents the edge of the screen); the vertical axis represents the relative brightness ratio, and 1 is the brightness of the module center (the specific brightness varies depending on the product specifications and is not limited. Taking this product as an example, the brightness of the module center is 520-550 nits). Figures 20-23 are partial schematic diagrams taken from the entire display screen, and the partial schematic diagrams include the edge represented by 0mm.) Figure 20 shows a simulated image with 10% haze, Figure 21 shows a simulated image with 30% haze (the image is simulated based on brightness curve 1006 in Figure 19, with the horizontal axis representing the distance to the screen edge (0mm represents the screen edge)), Figure 22 shows a simulated image with 50% haze (the image is simulated based on brightness curve 1005 in Figure 19, with the horizontal axis representing the distance to the screen edge (0mm represents the screen edge)), and Figure 23 shows a simulated image with 65% haze. Generally, we use the edge brightness at 5mm as the criterion for edge image quality. When the haze of the second part 22 is between 30% and 50%, the edge brightness curve is above 90%, and the uniformity of the simulated visual image is good. When the haze of the second part 22 exceeds 50%, the edge brightness curve drops significantly, and the simulated image edges become noticeably darker (Figure 23 shows a simulated image with 65% haze; the brightness curve at 5mm from the screen edge is below 85%). When the haze of the second part 22 is less than 30%, the simulated image edges are bright at 10% haze, and the uniformity optimization effect is limited (refer to Figure 20; the relative brightness value at 5mm from the edge is higher than the relative brightness values ​​on its adjacent sides, resulting in bright lines on the screen). This does not achieve the desired technical effect and is not considered. Therefore, in this embodiment, the haze of the second part 22 is 30% to 50%, resulting in a good image effect, practical implementation significance, and achieving the desired technical effect.

[0096] In an exemplary embodiment, the first part 21 has a protrusion 215 at one end away from the base plate 11, and the second part 22 has a groove 225 at one end near the first part 21. The groove 225 and the protrusion 215 cooperate to allow the first part 21 and the second part 22 to be inserted together. The thick black arrow in FIG6 indicates the assembly direction of the first part 21 and the second part 22.

[0097] For example, in the direction perpendicular to the base plate 11, the cross-sectional shape of the first part away from the base plate is constructed as an L-shaped structure, and the second part 22 is connected to the L-shaped structure on the side near the center of the back plate 1.

[0098] The L-shaped structure includes a first side 212 and a second side that are perpendicular to each other. The second side is parallel to the base plate 11. The protrusion 215 includes a fourth connecting surface connected to the first side 212 and a fifth connecting surface connected to the second side.

[0099] In a direction away from the first side 212 (refer to the X direction in FIG4), the protrusion 215 includes a limiting portion that limits the second portion 22.

[0100] The limiting portion of the protrusion 215 cooperates with the L-shaped structure to improve the connection stability of the first part 21 and the second part 22. The second part 22 is limited and fixed in a direction perpendicular to the first side 212, and is limited and fixed in both directions away from and towards the first side 212. The second part 22 is used to support the diffuser plate 3, and in the direction perpendicular to the second side, the weight of the diffuser plate 3 can achieve the limiting and fixing of the second part 22.

[0101] In an exemplary embodiment, referring to FIG24, in the direction away from the first side 212, the protrusion 215 includes a first connecting portion 2151 and a second connecting portion 2152. The first connecting portion 2151 and the second connecting portion 2152 have a T-shaped structure. The side of the first connecting portion 2151 away from the second connecting portion 2152 is the fourth connecting surface, and the second connecting portion 2152 is the limiting portion.

[0102] It should be noted that the protrusion 215 can also be other shapes, such as rhombus, triangle, cylinder, etc. Referring to Figures 27-29, as long as it can cooperate with the L-shaped structure of the first part 21, it can limit and fix the second part 22 in the direction perpendicular to the first side 212, and limit and fix the second part 22 in both the direction away from the first side 212 and the direction close to the first side 212.

[0103] In an exemplary embodiment, the protrusion 215 can be an integral structure, or when the middle frame 2 is rectangular in general, a strip-shaped protrusion 215 can be provided for each side of the rectangle.

[0104] In an exemplary embodiment, in the circumferential direction of the middle frame 2, a plurality of protrusions 215 are provided at intervals on the first part 21, and a plurality of grooves 225 that cooperate with the corresponding protrusions 215 are provided on the corresponding second part 22.

[0105] In an exemplary embodiment, when a plurality of protrusions 215 are provided at intervals on the first portion 21 in the circumferential direction of the middle frame 2, the plurality of protrusions 215 include at least one first positioning protrusion 215 for positioning the second portion 22. In the circumferential direction of the middle frame 2, the length of the first positioning protrusion 215 is greater than the length of the remaining protrusions 215 among the plurality of protrusions 215.

[0106] In an exemplary embodiment, the first positioning protrusion 215 includes a first sub-positioning protrusion 215 and a second sub-positioning protrusion 215. In the circumferential direction of the middle frame 2, the length of the first sub-positioning protrusion 215 is greater than the length of the second sub-positioning protrusion 215. The first sub-positioning protrusion 215 is used to achieve fine positioning of the second part 22, and the second sub-positioning protrusion 215 is used to achieve coarse positioning of the second part 22.

[0107] For example, referring to FIG28, in the circumferential direction of the middle frame 2, the length L1 of the first sub-positioning protrusion 215 is 20-30mm, and the length L2 of the second sub-positioning protrusion 215 is 15-25mm, but is not limited thereto.

[0108] It should be noted that when multiple protrusions 215 are spaced apart on the first portion 21 in the circumferential direction of the middle frame 2, the number of protrusions 215 can be set according to actual needs. In some embodiments, the middle frame 2 is rectangular in shape, with 5 protrusions 215 corresponding to the long side of the rectangle and 3 protrusions 215 corresponding to the short side of the rectangle, as shown in Figure 28, but this is not a limitation.

[0109] It should be noted that only the protrusion 215 on one long side and one short side is shown in Figure 28. It should be understood that the protrusion 215 is also provided on the other long side and the other short side of the rectangle.

[0110] It should be noted that, in the above description, the length of the protrusion 215 or other structure in the circumferential direction of the middle frame 2 corresponds to the overall shape of the middle frame 2. For example, when the middle frame 2 is rectangular, the length of the protrusion 215 or other corresponding structure is the length in the extension direction corresponding to the corresponding side of the middle frame 2.

[0111] In some embodiments, the middle frame 2 is rectangular in shape, with six protrusions 215 spaced apart on the long side of the rectangle and four protrusions 215 spaced apart on the short side of the rectangle. While ensuring the support strength of the protrusions 215, the length of the protrusions 215 in the extension direction of the corresponding side of the rectangle can be set to a minimum of 4mm. In this embodiment, the second part 22 includes multiple transparent sub-parts. If the number and distribution of the transparent sub-parts correspond to the protrusion 215, the length of the transparent sub-parts can be set to 7mm in the extension direction of the corresponding side of the rectangle, as shown in Figure 15. According to this structural form, the total length D of the second part 22 in the circumferential direction of the middle frame 2 is 140mm, which is greater than 97.5mm, satisfying the fixed bonding strength requirement (the total length of the adhesive layer 6 between the second part 22 and the diffuser plate 3 is the same as the total length of the corresponding second part 22). In order to optimize the design scheme and reduce the mold opening cost, the size of each transparent sub-part is consistent corresponding to the long and short sides of the rectangle, and the spacing between adjacent transparent sub-parts is consistent to prevent image differences.

[0112] In an exemplary embodiment, the backlight module further includes a frame 5 surrounding the periphery of the back plate 1. The frame 5 serves to fix and protect the overall module, and is commonly made of SGCC (hot-dip galvanized steel sheet) or SUS304 (stainless steel). The frame 5 includes a side frame 5 located around the periphery of the side plate 12. In a direction parallel to the bottom plate 11, the maximum distance between the inner side surface of the middle frame 2 and the frame 5 is 6.5-7mm.

[0113] Comparing Figures 29 and 30, for conventional solutions, such as the one shown in Figure 1, the distance between the inner side of the middle frame 2 and the frame 5 in the direction parallel to the base plate 11 is 8mm. In this embodiment, the distance between the inner side of the middle frame 2 and the frame 5 in the direction parallel to the base plate 11 is shortened, reducing the intrusion of the inner sidewall of the middle frame 2 into the AA area, thus reducing the amount of light blocked and improving brightness.

[0114] For the first structural form of the second part 22 adopting an arc-shaped bird's beak structure, the tangent of the second arc surface 223 is the extreme angle at which light enters the second part 22. The light 1007 at this position should be located above the protrusion 215 (on the side away from the base plate 11), referring to Figure 31, so as not to be blocked by the protrusion 215, and to ensure that the light is utilized to the maximum extent and enters the edge area. If the distance between the inner side of the middle frame 2 and the frame 5 is too small in the direction parallel to the base plate 11, the light incident on the second part 22 in the direction parallel to the tangent of the second arc surface 223 will be blocked by the protrusion 215 and reflected by the protrusion 215. In this way, the light effect in the edge area will be lost. Referring to Figure 32, the light 1007 is blocked by the protrusion 215. Therefore, in some embodiments, the distance between the inner side of the middle frame 2 and the frame 5 in the direction parallel to the base plate 11 is 6.5mm to 7mm.

[0115] It should be noted that the angle of the incident light parallel to the extension direction of the maximum common tangent of the second arc surface 223 is a constant value, which is independent of the change in horizontal intrusion (i.e., the distance between the inner side of the middle frame 2 and the frame 5) and is related to the shape and size of the second arc surface 223. The specific size of the second arc surface 223 is not required here. Generally, the angle of the incident light parallel to the extension direction of the maximum common tangent of the second arc surface 223 is 75° to 85°.

[0116] Based on the comprehensive analysis of the angle of the incident light parallel to the extension direction of the maximum common tangent of the second arc surface 223 and the minimum distance (6.5mm) between the inner side of the middle frame 2 and the side frame 5, the thickness of the protrusion 215 in the direction perpendicular to the base plate 11 is 3.5mm to 5mm.

[0117] Simulations were performed on the scheme to reduce intrusion, and the simulation results are shown in Figures 33-36. Compared with the conventional scheme (where the distance between the inner side of the middle frame 2 and the edge 5 is 8mm in the direction parallel to the base plate 11, the simulation results are shown in Figures 33 and 34, where Figure 34 is a brightness curve diagram, the horizontal axis of Figure 34 represents the distance to the screen edge (0mm represents the screen edge), and the vertical axis represents the light intensity. The relative brightness value of the position where the brightness curve in Figure 34 tends to be horizontal is 1 (1 is the brightness of the module center (the specific brightness varies depending on the product specifications and is not limited), and Figure 33 is a schematic diagram of the simulated display based on the brightness curve in Figure 34), in this embodiment, the brightness of the edge area is effectively improved, and the uniformity is also better than the original scheme (the simulation results of the structure in this embodiment are shown in Figures 35 and 36, where Figure 36 is a brightness curve diagram, the horizontal axis of Figure 36 represents the distance to the screen edge). 0mm represents the edge of the screen. The vertical axis represents the light intensity, and the relative brightness value of the position where the brightness curve in Figure 34 tends to be horizontal is 1 (1 is the brightness of the module center (the specific brightness varies depending on the product specification and is not limited)). Figure 35 is a schematic diagram of the simulated display based on the brightness curve in Figure 36. Comparing Figure 34 and Figure 36, it can be seen from the edge brightness curve that after shortening the distance between the inner side of the middle frame 2 and the frame 5 in the direction parallel to the base plate 11, the slope of the curve at the position 1-3mm from the edge of the product (corresponding to the coordinates -100 to -95mm shown in Figures 33-36; Figures 33-35 are partial schematic diagrams taken from the entire display screen, and the partial schematic diagrams include the edge represented by 0mm). The brightness increases more rapidly, so the light effect is significantly improved at the position 1-3mm from the edge of the product, and the amount of light entering at the outermost edge is higher than that of the conventional solution.

[0118] In an exemplary embodiment, a portion of the outer side of the frame 5 is recessed to form a recess 51. A first screw hole is provided on the recess 51, and a second screw hole is provided on the side plate 12 to cooperate with the first screw hole for screws to pass through. Along the direction away from the base plate 11, the size of the recess 51 gradually increases, and the first screw hole is located on the side of the recess 51 closer to the base plate 11. That is, the distance from the first screw hole to the top of the recess 51 is greater than the distance from the first screw hole to the bottom of the recess 51, as shown in Figure 4.

[0119] In some embodiments, the recess 51 is teardrop-shaped, increasing the distance between the first screw hole and the top of the frame 5. The buffer deformation of the recess 51 is used to prevent the frame 5 from turning outward during screw fastening.

[0120] In an exemplary embodiment, the maximum distance between the first screw hole and the end face of the frame 5 away from the base plate 11 is 10mm, and the maximum height of the second part 22 in the direction perpendicular to the base plate 11 is 7mm.

[0121] In this embodiment, the middle frame 2 is configured as a first portion 21 located near the base plate 11 of the back plate 1, and a second portion 22 located away from the back plate 1 of the base plate 11. The second portion 22 is configured as a transparent structure with a transmittance greater than or equal to 90%, increasing the amount of light entering the product's edge area. In the direction perpendicular to the base plate 11, the higher the second portion 22, the more light can enter the edge area, resulting in a greater increase in edge brightness. In some embodiments, the height of the second portion 22 is increased by shortening the distance between the first screw hole and the base plate 11. Referring to Figure 37, the left image in Figure 37 is a schematic diagram without shortening the distance between the first screw hole and the base plate 11, while Figure 37 is a schematic diagram after shortening the distance between the first screw hole and the base plate 11.

[0122] By simulation, the fixing point where the back plate 1 and the first screw hole are fixed by bolts is found to move closer to the base plate 11 to meet the overall support structure strength and the limit range of preventing the frame 5 from turning outward. First, the simulation object is simplified. The main simulation content of this extended scheme is to ensure that when the first screw hole decreases with the height of the back plate 1, the top outward turning amount of the frame 5 is less than 0.5mm (the distance from the AA area to the edge of the display panel 10) during normal use. If it exceeds 0.5mm, the outward turning amount of the frame 5 is too large, which may cause the display panel to jump off. The simplified model retains the back plate 1 and the frame 5, and fixes the first screw hole position to apply torque to the back plate 1.

[0123] The outward turning amount of the frame 5 varies depending on the different distances between the first screw hole and the base plate 11, as shown in Table 2 below.

[0124] Table 2

[0125] The screw hole fastening height in Table 2 is the distance between the first screw hole and the base plate 11. The results show that, to meet the maximum outward flare of the frame 5 (0.5mm), the maximum distance between the first screw hole and the end face of the frame 5 furthest from the base plate 11 is 10mm. In the direction perpendicular to the base plate 11, the maximum height of the second part 22 is 7mm. Optical simulation was performed on the above data, and the brightness curve of the product edge area is shown in Figure 38. The blue curve 3001 represents the brightness curve without shortening the distance between the first screw hole and the base plate 11, and the yellow curve 3002 represents the brightness curve with the distance shortened. The brightness at a position 5mm from the edge is 98%, which is approximately 3% higher than the brightness curve without shortening the distance between the first screw hole and the base plate 11.

[0126] This disclosure also provides a display device, including the backlight module described above, and a display panel 10 located on the light-emitting side of the backlight module.

[0127] For example, the display panel 10 uses liquid crystal material as the basic component, fills the space between two oppositely arranged substrates with liquid crystal material, and uses an active matrix driven by thin film transistors to change the arrangement of molecules inside the liquid crystal material by voltage, thereby realizing the display of different images.

[0128] Referring to Figure 4, by way of example, the backlight module further includes a light source and a reflector 7 disposed on the base plate 11. The light source includes a flexible circuit board and a plurality of LED beads arranged in an array on the flexible circuit board. The reflector 7 is provided with a plurality of through holes corresponding to the plurality of LED beads. The LED beads pass through the through holes, so that the reflector 7 is disposed on the flexible circuit board.

[0129] A limiting block 201 is provided on the side of the middle frame 2 away from the back plate 12. The limiting block 201 is located on the side of the reflective sheet 7 away from the bottom plate 11 to limit and fix the reflective sheet 7.

[0130] The following points need to be explained:

[0131] (1) The accompanying drawings of the embodiments of this disclosure only involve the structures involved in the embodiments of this disclosure. Other structures can be referred to the general design.

[0132] (2) For clarity, the thickness of layers or regions is enlarged or reduced in the drawings used to describe embodiments of the present disclosure, i.e., these drawings are not drawn to actual scale. It will be understood that when an element such as a layer, film, region or substrate is referred to as being “above” or “below” another element, the element may be “directly” located “above” or “below” the other element or there may be intermediate elements.

[0133] (3) Where there is no conflict, the embodiments of this disclosure and the features in the embodiments can be combined with each other to obtain new embodiments.

[0134] It is understood that the above embodiments are merely exemplary embodiments used to illustrate the principles of this disclosure, and this disclosure is not limited thereto. For those skilled in the art, various modifications and improvements can be made without departing from the spirit and substance of this disclosure, and these modifications and improvements are also considered to be within the scope of protection of this disclosure.

Claims

1. A backlight module for providing a light source to a display panel, characterized in that, include: The back panel includes a bottom panel and side panels surrounding the bottom panel; The middle frame includes a first part and a second part. The first part is arranged around the perimeter of the base plate, and the second part is arranged at the end of the first part away from the base plate. The transmittance of the second part is greater than or equal to 90%.

2. The backlight module according to claim 1, characterized in that, The first part includes a first inclined surface and a first connecting surface for connecting the second part, wherein the connection between the first inclined surface and the first connecting surface is constructed as a first arc surface; The second part includes a second connecting surface connected to the first connecting surface, a second arc surface connected to the first arc surface, and a second inclined surface with one end connected to the second arc surface, the second inclined surface extending away from the base plate.

3. The backlight module according to claim 1, characterized in that, In the direction perpendicular to the base plate, the cross-sectional shape of the second part is trapezoidal. The first part includes a first connecting surface for connecting with the second part, and the second part includes a third connecting surface for connecting with the first connecting surface. The end of the third connecting surface away from the side plate is exposed outside the first connecting surface.

4. The backlight module according to claim 1, characterized in that, It also includes a diffuser plate, and an adhesive layer is provided between the second part and the diffuser plate.

5. The backlight module according to claim 1, characterized in that, The second part is an integral structure, or in the circumferential direction of the first part, the second part includes a plurality of transparent sub-parts spaced apart.

6. The backlight module according to claim 5, characterized in that, In the circumferential direction of the first part, the total length D of the second part satisfies the following formula: D≥(0.16~0.26)*G.

7. The backlight module according to claim 1, characterized in that, The haze in the second part is 30% to 50%.

8. The backlight module according to claim 1, characterized in that, The first part has a protrusion at the end away from the base plate, and the second part has a groove at the end near the first part. The groove and the protrusion cooperate to allow the first part and the second part to be inserted together.

9. The backlight module according to claim 8, characterized in that, In a direction perpendicular to the base plate, the cross-sectional shape of the first part away from the base plate is constructed as an L-shaped structure, and the second part is connected to the L-shaped structure on the side near the center of the back plate. The L-shaped structure includes a first side and a second side arranged perpendicularly to each other. The second side is arranged parallel to the base plate. The protrusion includes a fourth connecting surface connected to the first side and a fifth connecting surface connected to the second side. In a direction away from the first side, the protrusion includes a limiting portion that limits the second part.

10. The backlight module according to claim 9, characterized in that, In the direction away from the first side, the protrusion includes a first connecting portion and a second connecting portion, the first connecting portion and the second connecting portion having a T-shaped structure, the side of the first connecting portion away from the second connecting portion being the fourth connecting surface, and the second connecting portion being the limiting portion.

11. The backlight module according to claim 1, characterized in that, It also includes a frame surrounding the periphery of the back panel, the frame including a side frame located around the periphery of the side panel, and the maximum distance between the inner side of the middle frame and the frame in a direction parallel to the bottom plate is 6.5-7mm.

12. The backlight module according to claim 11, characterized in that, The outer side of part of the frame is recessed to form a recess, and a first screw hole is provided in the recess. A second screw hole is provided on the side plate to cooperate with the first screw hole for screws to pass through. The size of the recess gradually increases along the direction away from the base plate.

13. The backlight module according to claim 12, characterized in that, The maximum distance between the first screw hole and the end face of the frame away from the base plate is 10mm, and the maximum height of the second part in the direction perpendicular to the base plate is 7mm.

14. A display device, characterized in that, Includes the backlight module as described in any one of claims 1-13.

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