Backlight module and display terminal

Abstract

The invention relates to a backlight module and a display terminal. The backlight module comprises a light guide plate, a light bar and a light guide cover. The lamp strip comprises a flexible circuit board and a plurality of lamp beads, the lamp beads correspond to the side wall of the light guide plate, and part of the flexible circuit board is located on the surface of the side, opposite to the light emitting face, of the light guide plate. The lamp guide cover comprises an upper plate, a lower plate and a middle plate, the upper plate and the lower plate are opposite, the middle plate is connected with the upper plate and the lower plate, the lower plate at least wraps the flexible circuit board, the upper plate at least wraps the lamp beads and the edge, close to the lamp beads, of the light guide plate, and the expansion coefficient of the lamp guide cover is smaller than or equal to that of the light guide plate. A flexible circuit board is connected with the lower surface of a light guide plate, meanwhile, a lower plate wraps the flexible circuit board, an upper plate wraps a light emitting face 10a of the light guide plate, and the upper plate and the lower plate are connected through a middle plate. The lamp guide cover can reduce the deformable space of the light guide plate and the flexible circuit board, so that the wrinkle degree of the flexible circuit board is reduced.

Description

Technical Field

[0001] The present application relates to the field of display technologies, and in particular, to a backlight module and a display terminal. Background Art

[0002] In the display field, liquid crystal display products are technically mature and widely used. A liquid crystal display product includes a liquid crystal panel and a backlight module. Since the liquid crystal panel itself does not emit light, it needs to rely on the backlight module to provide a backlight source. The uniformity of the light output of the backlight source directly affects the display effect of the liquid crystal display product.

[0003] The backlight module needs to adapt to application scenarios at various temperatures. To verify the reliability of the backlight module at various temperatures, a thermal shock test is usually performed on the backlight module. During the thermal shock test, uneven brightness appears on the light-emitting surface of the backlight module.

[0004] Therefore, it is urgent to improve the above technical problems. Summary of the Invention

[0005] Embodiments of the present application provide a backlight module and a display terminal to improve the technical problem of uneven brightness on the light-emitting surface of the backlight module during the thermal shock test.

[0006] To achieve the above object, according to the first aspect of the present application, there is provided a backlight module, including:

[0007] A light guide plate, including a light-emitting surface;

[0008] A light bar, including a flexible circuit board and a plurality of lamp beads provided on one side of the flexible circuit board. The plurality of lamp beads correspond to the side wall of the light guide plate, and a part of the flexible circuit board is located on the surface of the light guide plate opposite to the light-emitting surface;

[0009] A light guide cover, including an upper plate and a lower plate opposite to each other, and a middle plate connecting the upper plate and the lower plate. The lower plate at least covers the flexible circuit board, the upper plate at least covers the lamp beads and the edge of the light guide plate near the lamp beads, and the expansion coefficient of the light guide cover is less than or equal to the expansion coefficient of the light guide plate.

[0010] Optionally, the surface of the flexible circuit board facing away from the light guide plate is in contact with the lower plate, the upper plate is connected to the light-emitting surface of the light guide plate, and a first adhesive layer is provided between the upper plate and the light-emitting surface of the light guide plate. The first adhesive layer bonds the upper plate and the light guide plate.

[0011] Optionally, a second adhesive layer is provided between the flexible circuit board and the light guide plate. The second adhesive layer bonds the light guide plate and the flexible circuit board.

[0012] Optionally, the second adhesive layer includes a plurality of spaced adhesive segments, and the adhesive segments are disposed corresponding to the gaps between two adjacent lamp beads.

[0013] Optionally, the surfaces of the upper plate, the middle plate, and the lower plate close to the lamp beads are all white.

[0014] Optionally, the backlight module further includes a backplate, the backplate includes a bottom plate and side plates disposed around the bottom plate, the bottom plate and the side plates form a receiving cavity, and the backplate further includes a first folded edge corresponding to the upper plate, and the first folded edge is connected to one of the side plates;

[0015] Wherein, the lower plate is in contact with the bottom plate, and the upper plate is in contact with the first folded edge.

[0016] Optionally, the edge of the upper plate on the side away from the side plate extends beyond the edge of the first folded edge on the side away from the side plate.

[0017] Optionally, the hardness of the lamp guide cover is greater than the hardness of the light guide plate.

[0018] Optionally, the material of the lamp guide cover includes glass fiber reinforced plastic, liquid crystal polymer, and polyphenylene sulfide.

[0019] According to a second aspect of the present application, there is provided a display terminal, including a display panel and the above-mentioned backlight module.

[0020] In the backlight module of the embodiment of the present application, by disposing the flexible circuit board on the surface of the light guide plate opposite to the light-emitting surface, and at the same time using the lower plate to cover the flexible circuit board and the upper plate to cover the light-emitting surface of the light guide plate, and connecting the upper plate and the lower plate through the middle plate. Since the expansion coefficient of the lamp guide cover is smaller than the expansion coefficient of the light guide plate, when the light guide plate expands or contracts, the lamp guide cover can reduce the deformable space of the light guide plate and the flexible circuit board, thereby reducing the degree of wrinkling of the flexible circuit board and reducing the influence of the wrinkling of the flexible circuit board on the distance between the lamp beads and the light guide plate, and further improving the brightness non-uniformity.

[0021] Other features and advantages of the present application will be described in detail in the subsequent specific implementation part. Description of the Drawings

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the following drawings are only some embodiments of the present application. For those skilled in the art, without creative efforts, other drawings can be obtained according to these drawings.

[0023] To more fully understand the present application and its beneficial effects, the following description will be made in conjunction with the accompanying drawings, where the same reference numerals in the following description represent the same parts.

[0024] Figure 1 is a top view structural schematic diagram of a backlight module provided in an exemplary embodiment of the present disclosure;

[0025] Figure 2 is Figure 1 a cross-sectional structural schematic diagram taken at C-C in

[0026] Figure 3 is Figure 2 a top view schematic diagram of a partial structure in

[0027] Figure 4 is Figure 1 a cross-sectional structural schematic diagram taken at D-D in

[0028] Figures 5A to 5C is a schematic diagram of an assembly method of a backlight module provided in an exemplary embodiment of the present disclosure;

[0029] Figure 6 is a structural schematic diagram of a display terminal provided in an exemplary embodiment of the present disclosure.

[0030] Description of reference numerals:

[0031] 1 - Backlight module;

[0032] 10 - Light guide plate; 10a - Light emitting surface;

[0033] 20 - Lamp strip; 21 - Lamp bead; 22 - Flexible circuit board; 23 - Reflective film;

[0034] 30 - Lamp guide cover; 31 - Upper plate; 32 - Middle plate; 33 - Lower plate;

[0035] 41 - First adhesive layer; 42 - Second adhesive layer; 421 - Adhesive section; 43 - Notch glue;

[0036] 50 - Back plate; 51 - First folded edge; 52 - Side plate; 53 - Bottom plate;

[0037] 61 - Optical film; 62 - Reflective sheet;

[0038] 70 - Middle frame;

[0039] D1 - First direction; D2 - Second direction;

[0040] 2 - Display terminal; 3 - Display panel; 301 - First substrate; 302 - Second substrate; 303 - First polarizer; 304 - Second polarizer. Detailed implementation manners

[0041] Next, the technical solutions in the embodiments of the present application will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative efforts belong to the protection scope of the present application.

[0042] To achieve the above object, according to the first aspect of the present application, as Figures 1 to 3 shown, a backlight module 1 is provided, including a light guide plate 10, a lamp strip 20, and a lamp guide cover 30; the light guide plate 10 includes a light-emitting surface 10a, the lamp strip 20 includes a flexible circuit board 22 and a plurality of lamp beads 21 disposed on one side of the flexible circuit board 22, the plurality of lamp beads 21 correspond to the side wall of the light guide plate 10, and a part of the flexible circuit board 22 is located on the surface of the light guide plate 10 opposite to the light-emitting surface 10a; the lamp guide cover 30 includes an upper plate 31 and a lower plate 33 opposite to each other, and a middle plate 32 connecting the upper plate 31 and the lower plate 33, the lower plate 33 at least covers the flexible circuit board 22, the upper plate 31 at least covers the lamp beads 21 and the edge of the light guide plate 10 near the lamp beads 21, and the expansion coefficient of the lamp guide cover 30 is less than or equal to the expansion coefficient of the light guide plate 10.

[0043] The backlight module 1 can provide a backlight source for a liquid crystal panel or the like. Among them, the light guide plate 10 can evenly distribute the light emitted by a point light source or a line light source on the entire plane.

[0044] As Figure 2 shown, the light guide plate 10 can be in the shape of a rectangular thin plate. The light guide plate 10 includes an upper surface and a lower surface opposite to each other. The upper surface and the lower surface are the two surfaces with the largest area in the light guide plate 10, and the upper surface and the lower surface are connected by a plurality of side walls. The light-emitting surface 10a is the upper surface of the light guide plate 10.

[0045] In some embodiments, the light guide plate 10 can be manufactured by an injection molding process. First, the optical-grade plastic particles are heated to a molten state, and then injected into a mold with a specific shape. After cooling and solidifying, the basic shape of the light guide plate 10 is formed.

[0046] In some embodiments, the light guide plate 10 can be made of materials such as optical-grade acrylic (PMMA) or polycarbonate (PC). Acrylic has good optical properties, such as high light transmittance and low haze, and can effectively transmit and scatter light. At the same time, it has good processing performance and surface quality, and is easy to be made into light guide plates 10 of various shapes and sizes. Polycarbonate has higher strength and impact resistance, and is suitable for occasions with higher mechanical property requirements for the light guide plate 10.

[0047] As Figure 2As shown, the light bar 20 is used to provide a linear light source. The light bar 20 includes a flexible circuit board 22 (Flexible Printed Circuit, FPC) and a plurality of lamp beads 21. The plurality of lamp beads 21 can be connected to the flexible circuit board 22 by soldering or other means. Connection traces are provided on the flexible circuit board 22, and the connection traces can connect the plurality of lamp beads 21 in series and / or in parallel. The light bar 20 can be connected to an external structure, and the external structure is used to provide power for the light bar 20 to drive the lamp beads 21 to emit light.

[0048] In some embodiments, the lamp beads 21 can be light-emitting diodes (LEDs) or the like.

[0049] In the embodiments of the present application, as Figure 2 and Figure 3 shown, the backlight module 1 is a side-entry backlight. The plurality of lamp beads 21 are arranged along the first direction D1. The surface of the lamp bead 21 on the side close to the side wall of the light guide plate 10 is the light-emitting surface of the lamp bead 21, and the side wall of the light guide plate 10 close to the light-emitting surface of the lamp bead 21 is the light-incident surface. The light emitted from the lamp bead 21 is incident into the light guide plate 10 from the side wall of the light guide plate 10, and after refraction and reflection inside the light guide plate 10, it exits from the light-emitting surface 10a of the light guide plate 10. The light-emitting surface of the lamp bead 21 is close to the side wall of the light guide plate 10, so that as much light as possible emitted from the lamp bead 21 can be incident into the light guide plate 10, improving the brightness of the backlight module 1.

[0050] As Figure 2 shown, the lamp guide cover 30 includes an upper plate 31 and a lower plate 33 opposite to each other, and a middle plate 32 connecting the upper plate 31 and the lower plate 33. The upper plate 31, the middle plate 32 and the lower plate 33 can be made of the same material. The material of the lamp guide cover 30 can be plastic or the like, but is not limited thereto.

[0051] The upper plate 31, the middle plate 32 and the lower plate 33 can form a U-shaped structure, and the light bar 20 and one end of the light guide plate 10 close to the light bar 20 can be embedded in the lamp guide cover 30. Among them, the upper plate 31 covers the lamp beads 21 and the edge of the light guide plate 10 close to the lamp beads 21, the lower plate 33 covers the flexible circuit board 22, and the lamp beads 21 are located between the middle plate 32 and the light guide plate 10. Here, the lower plate 33 covering the flexible circuit board 22 means that the lower plate 33 is close to the flexible circuit board 22 and covers the flexible circuit board 22. The upper plate 31 covering the lamp beads 21 and the edge of the light guide plate 10 close to the lamp beads 21 means that the upper plate 31 is close to the lamp beads 21 and covers the lamp beads 21, and the upper plate 31 is close to the light guide plate 10 and covers the edge of the light guide plate 10 close to the lamp beads 21.

[0052] The inventors of the present application found that during the thermal shock test, the light-emitting surface of the backlight module 1 exhibited uneven brightness. After further analysis, the inventors found that the phenomenon of uneven brightness mainly concentrated in the area near the light bar 20. This is because when the light guide plate 10 expands or contracts, its size changes significantly, causing the flexible circuit board 22 to be squeezed or pulled. Since the flexible circuit board 22 is made of a flexible material, wrinkles appear after being stressed. The lamp beads 21 are fixed on the flexible circuit board 22. When the flexible circuit board 22 has wrinkles, the distance between the light-emitting surface of the lamp beads 21 and the light-incident surface of the light guide plate 10 will change. When the distances between the light-emitting surfaces of multiple lamp beads 21 and the light-incident surface of the light guide plate 10 are different, the total amount of light incident from the lamp beads 21 into the light guide plate 10 is different, resulting in uneven brightness in the area of the backlight module 1 near the light bar 20.

[0053] Since the volume of the light guide plate 10 is relatively large compared to the flexible circuit board 22, the light guide plate 10 is more affected by temperature, humidity, etc. In the present application, the light guide plate 10 and the flexible circuit board 22 are embedded in the lamp guide cover 30. When the light guide plate 10 expands or contracts, the lamp guide cover 30 can reduce the deformable space of the light guide plate 10 and the flexible circuit board 22, thereby reducing the degree of wrinkles of the flexible circuit board 22, and further reducing the variation range of the distance between the light-emitting surface of the lamp beads 21 and the light-incident surface of the light guide plate 10, and improving the phenomenon of uneven brightness.

[0054] It should be noted that the expansion coefficient includes the thermal expansion coefficient, the moisture expansion coefficient, etc. The thermal expansion coefficient refers to the ratio of the relative change in the length, area or volume of an object to the change in temperature when the temperature changes. The thermal expansion coefficient describes the degree of expansion or contraction of an object as the temperature rises or falls. The moisture expansion coefficient is used to describe the property of a material expanding after absorbing moisture or other solvents, usually expressed as the rate of size change of the material under a unit change in humidity. For some hydrophilic materials, such as wood, paper, certain polymer materials, etc., when the environmental humidity changes, the material will absorb or release moisture, resulting in a change in its size.

[0055] The expansion and contraction of the light guide plate 10 are affected by both temperature and humidity. When the temperature rises, the light guide plate 10 expands; when the temperature drops, the light guide plate 10 contracts. When the light guide plate 10 absorbs water, the light guide plate 10 expands; when the light guide plate 10 loses water, the light guide plate 10 contracts.

[0056] In some embodiments, as Figure 2 shown, the backlight module 1 further includes an optical film 61. The optical film 61 is disposed on one side of the light-emitting surface 10a of the light guide plate 10. The optical film 61 may include a diffusion sheet, a prism sheet, etc. stacked in sequence. The diffusion sheet is used to diffusely reflect the light emitted from the light guide plate 10, making the light evenly distributed and effectively homogenizing the light.

[0057] The prism sheet is disposed on the side of the diffusion sheet away from the light guide plate 10. Through the principles of refraction and reflection of light, the prism sheet corrects the direction of light, concentrates the scattered light towards the front, and improves the brightness of the backlight module 1.

[0058] The number of diffusion areas and prism sheets can be set as needed. For example, the optical film 61 may include four sheets, which are, in sequence, a diffusion sheet, a prism sheet, a prism sheet, and a diffusion sheet, but is not limited thereto.

[0059] In some embodiments, as Figure 2 shown, the backlight module 1 further includes a reflective sheet 62, and the reflective sheet 62 is disposed on one side of the lower surface of the light guide plate 10. The reflective sheet 62 is mainly used to reflect the light emitted from the bottom of the light guide plate 10 back into the light guide plate 10, so that it can be concentrated and projected from the front, reduce light loss, and increase the light source efficiency of the backlight module 1.

[0060] In some embodiments, as Figure 1 and Figure 2 shown, the backlight module 1 further includes a notch adhesive 43, and the notch adhesive 43 is disposed on the side of the optical film 61 away from the light guide plate 10. The notch adhesive 43 is used to paste and fix the optical film 61. For example, the notch adhesive 43 pastes the edge of the optical film 61 to the frame of the backlight module 1 to form a closed space, prevent light from leaking from the edge, and at the same time play a role in fixing the position of the optical film 61, so that they are neatly arranged during assembly and use, and ensure the brightness uniformity of the backlight module 1.

[0061] Optionally, as Figure 2 shown, the surface of the flexible circuit board 22 facing away from the light guide plate 10 is in contact with the lower plate 33, and the upper plate 31 is connected to the light-emitting surface 10a of the light guide plate 10.

[0062] The surface of the flexible circuit board 22 facing away from the light guide plate 10 is in contact with the lower plate 33. That is to say, the flexible circuit board 22 is in direct contact with the lower plate 33, and no other materials are provided between them.

[0063] The upper plate 31 is connected to the light-emitting surface 10a of the light guide plate 10. That is to say, the upper plate 31 is fixed to the light guide plate 10, and no relative movement occurs between the upper plate 31 and the light guide plate 10.

[0064] It should be noted that in order to enable the lamp guide cover 30 to be assembled with the light guide plate 10 and the lamp strip 20, in the thickness direction of the backlight module 1, there may be a small gap between the lamp guide cover 30 and the light guide plate 10. For example, in the thickness direction of the backlight module 1, the gap between the lamp guide cover 30 and the light guide plate 10 may be 0.05 mm to 0.07 mm. Among them, the thickness direction of the backlight module 1 refers to the direction perpendicular to the light-emitting surface 10a of the light guide plate 10. Please refer to Figure 1, the thickness direction of the backlight module 1 is perpendicular to the first direction D1, and the thickness direction of the backlight module 1 is perpendicular to the second direction D2.

[0065] Optionally, as Figure 2 shown, a first adhesive layer 41 is provided between the upper plate 31 and the light-emitting surface 10a of the light guide plate 10. The first adhesive layer 41 bonds the upper plate 31 and the light guide plate 10. The first adhesive layer 41 can be a double-sided tape or the like. By bonding the upper plate 31 and the light guide plate 10, the fixation between the upper plate 31 and the light guide plate 10 can be achieved, and the relative movement between the upper plate 31 and the light guide plate 10 can be prevented.

[0066] In some embodiments, the first adhesive layer 41 can be set as a white adhesive material. Since the white surface has a high reflectivity, it can reflect light and reduce the absorption of light by the first adhesive layer 41.

[0067] Optionally, a second adhesive layer 42 is provided between the flexible circuit board 22 and the light guide plate 10. The second adhesive layer 42 bonds the light guide plate 10 and the flexible circuit board 22. The second adhesive layer 42 can be a double-sided tape or the like. By bonding the flexible circuit board 22 and the light guide plate 10, the integration of the light guide and the light source can be achieved, that is, the integration of the light bar 20 and the light guide plate 10, which simplifies the assembly of the backlight module 1.

[0068] In some embodiments, in order to avoid the absorption of light by the second adhesive layer 42, the second adhesive layer 42 can be set as a white adhesive material. Since the white surface has a high reflectivity, it can reflect light and reduce the absorption of light by the second adhesive layer 42.

[0069] Optionally, as Figure 2 and Figure 3 shown, the second adhesive layer 42 includes a plurality of spaced adhesive segments 421, and the adhesive segments 421 are arranged corresponding to the gaps between adjacent two lamp beads 21. In order to avoid the absorption of light when the light enters the second adhesive layer 42, resulting in light loss, the second adhesive layer 42 can be set as a plurality of adhesive segments 421, and each adhesive segment 421 is arranged offset from the light-emitting direction of the lamp bead 21.

[0070] Specifically, the orthographic projection of the bonding segment 421 on the flexible circuit board 22 can be set at the gap between the orthographic projections of two adjacent lamp beads 21 on the flexible circuit board 22, and the bonding segment 421 is located on the side of the light-emitting surface of the lamp bead 21 close to the light guide plate 10, so that the bonding segment 421 is set outside the light-emitting range of the lamp bead 21. Through the above settings, when the bonding segment 421 faces the lamp bead 21, the shielding and absorption of the emitted light of the lamp bead 21 can be avoided. At the same time, if the second bonding layer 42 is connected and set, internal stress will be formed after the second bonding layer 42 expands or contracts, and the internal stress will pull the flexible circuit board 22, intensifying the wrinkling degree of the flexible circuit board 22. That is, by setting the second bonding layer 42 to include a plurality of bonding segments 421, the interaction between the bonding segments 421 can be reduced, the internal stress can be reduced, and the wrinkling degree of the flexible circuit board 22 can be reduced.

[0071] In some embodiments, as Figure 3 shown, a reflective film 23 is further provided on the flexible circuit board 22. The reflective film 23 can be a white single-sided adhesive, and the surface of the reflective film 23 with adhesiveness is bonded to the flexible circuit board 22. The reflective film 23 is provided with a plurality of avoidance openings, and the bonding segment 421 can be set in the avoidance openings.

[0072] It should be understood that the lamp bead 21, the reflective film 23 and the second bonding layer 42 are all located on the same side surface of the flexible circuit board 22. By providing the reflective film 23 on the flexible circuit board 22, the reflective film 23 can reflect the light back to the light guide plate 10, improving the utilization rate of the light.

[0073] Optionally, the surfaces of the upper plate 31, the middle plate 32 and the lower plate 33 close to the lamp bead 21 are all white. Since the white surface has a high reflectivity, the light can be reflected to the light guide plate 10, improving the utilization rate of the light.

[0074] In some embodiments, the lamp guide cover 30 can be made of a white material. The lamp guide cover 30 can be manufactured by an injection molding process. For example, white pigment particles are incorporated into transparent plastic particles, heated to a molten state, and then injected into a mold with a specific shape, and the lamp guide cover 30 is formed after cooling and solidification. The white pigment particles can dye the transparent plastic white, so that the lamp guide cover 30 becomes a white material.

[0075] In other embodiments, a white coating or the like can be provided on the inner surface of the lamp guide cover 30. At this time, the color of the material of the lamp guide cover 30 is not limited to white.

[0076] Optionally, as Figure 2 and Figure 4As shown, the backlight module 1 further includes a back plate 50. The back plate 50 includes a bottom plate 53 and side plates 52 disposed around the periphery of the bottom plate 53. The bottom plate 53 and the side plates 52 form a receiving cavity. The back plate 50 further includes a first folded edge 51 corresponding to the upper plate 31, and the first folded edge 51 is connected to one of the side plates 52. Among them, the lower plate 33 is in contact with the bottom plate 53, and the upper plate 31 is in contact with the first folded edge 51.

[0077] In some embodiments, the material of the back plate 50 can be metal materials such as stainless steel, iron, and aluminum. The back plate 50 includes a bottom plate 53 and side plates 52 disposed around the periphery of the bottom plate 53. The bottom plate 53 and the side plates 52 enclose a receiving space. The light guide plate 10, the lamp strip 20, etc. are disposed in the receiving space. Among them, a first folded edge 51 is further provided at the side plate 52 corresponding to the side of the lamp strip 20. The first folded edge 51 extends into the receiving space to fix the lamp guide cover 30 and prevent the lamp guide cover 30 from disengaging from the back plate 50.

[0078] In some embodiments, the first folded edge 51, the side plate 52, and the bottom plate 53 can be integrally formed. For example, the back plate 50 can be formed by stamping processes, etc. The first folded edge 51, the side plate 52, and the bottom plate 53 can form a U-shaped structure, and the lamp guide cover 30 is embedded in the U-shaped structure of the backlight. Through the above settings, the assembly efficiency can be improved.

[0079] Specifically, please refer to Figures 5A to 5C . As Figure 5A shown, the lamp strip 20 is bonded to the lower surface of the light guide plate 10 through a second bonding layer 42 to achieve the assembly of the lamp strip 20 and the light guide plate 10. A first bonding layer 41 is bonded to the light-emitting surface 10a of the light guide plate 10. As Figure 5B shown, the lamp strip 20 and the light guide plate 10 are embedded in the lamp guide cover 30. The light-emitting surface 10a of the light guide plate 10 corresponds to the upper plate 31, and the flexible circuit board 22 corresponds to the lower plate 33. The first bonding layer 41 is bonded to the upper plate 31. As Figure 5C shown, the assembled structures such as the lamp guide cover 30 are obliquely inserted into the back plate 50, so that the first folded edge 51 corresponds to the upper plate 31, the side plate 52 corresponds to the middle plate 32, and the bottom plate 53 corresponds to the lower plate 33 to complete the assembly of the structures such as the lamp guide cover 30. The backlight module 1 of the present application has low assembly difficulty and high assembly efficiency.

[0080] It should be noted that in order to enable the lamp guide cover 30 and the back plate 50 to be assembled, in the thickness direction of the backlight module 1, there can be a small gap between the lamp guide cover 30 and the back plate 50. For example, in the thickness direction of the backlight module 1, the gap between the lamp guide cover 30 and the back plate 50 can be 0.05 mm to 0.07 mm.

[0081] In some embodiments, as Figure 1 and Figure 4As shown, the backlight module 1 further includes a middle frame 70. The middle frame 70 is disposed within the accommodation space of the backplate 50 and is disposed around the outer periphery of the side walls of the light guide plate 10 other than the light incident surface. The middle frame 70 can be used to limit optical films 61, etc., to ensure the structural stability of the backlight module 1. The edge of the notch adhesive 43 close to the optical film 61 can be bonded to the upper surface of the optical film 61, and the edge of the notch adhesive 43 close to the middle frame 70 can be bonded to the upper surface of the middle frame 70, so as to fix the optical film 61 and shield the edge of the backlight module 1.

[0082] It should be understood that, as Figure 1 and Figure 2 shown, at the lower border of the backlight module 1, the edge of the notch adhesive 43 close to the optical film 61 can be bonded to the upper surface of the optical film 61, and the edge of the notch adhesive 43 close to the first folded edge 51 can be bonded to the first folded edge 51. Among them, the lower border is the border on the side of the backlight module 1 where the light bar 20 is disposed.

[0083] The notch adhesive 43 is a double-sided adhesive with light-shielding ability. The surface of the notch adhesive 43 away from the light guide plate 10 can be used to bond to a liquid crystal panel, etc.

[0084] In some embodiments, the material of the middle frame 70 can be plastic, etc. The middle frame 70 can be integrally formed by an injection molding process.

[0085] In some embodiments, the middle frame 70 can be snap-fitted or bonded to the backplate 50, but is not limited thereto. As Figure 4 shown, an adhesive material is disposed between the middle frame 70 and the side plate 52, and the middle frame 70 and the side plate 52 are bonded through the adhesive material.

[0086] Optionally, as Figure 2 shown, the edge of the upper plate 31 away from the side plate 52 extends beyond the edge of the first folded edge 51 away from the side plate 52. That is to say, the edge of the upper plate 31 close to the center of the backlight module 1 extends beyond the edge of the first folded edge 51 close to the center of the backlight module 1. Through the above settings, the lamp guide cover 30 can shield the edge of the first folded edge 51, avoiding the first folded edge 51 from absorbing light and causing uneven brightness near the first folded edge 51.

[0087] Optionally, the hardness of the lamp guide cover 30 is greater than the hardness of the light guide plate 10.

[0088] Hardness refers to the ability to describe the resistance of a material to deformation, indentation, or scratching. Hardness can be Shore hardness, Brinell hardness, Rockwell hardness, etc. For example, there are various types of Shore hardness testers, and the common ones are Shore A hardness tester and Shore D hardness tester. Shore A hardness tester is applicable to softer materials such as rubber and soft plastics; Shore D hardness tester is applicable to harder materials such as hard plastics and metals. The unit of Shore hardness is "degree", represented by the symbol "HA" or "HD". For example, "50HA" means the Shore A hardness is 50 degrees, and "70HD" means the Shore D hardness is 70 degrees.

[0089] When testing Shore hardness, place the hardness tester vertically on the surface of the material to be tested, gently press the indenter so that it contacts the material surface, and then read the scale value on the hardness tester, which is the Shore hardness value of the material to be tested. To ensure the accuracy of the test results, it is usually necessary to conduct multiple tests at different positions and take the average value.

[0090] In some embodiments, the Shore hardness of the lamp guide cover 30 is greater than 90HA, and the Shore hardness of the light guide plate 10 is less than 90HA. For example, the Shore hardness of the lamp guide cover 30 is 75HD to 100HD.

[0091] Since the hardness of the lamp guide cover 30 is greater than that of the light guide plate 10, when the light guide plate 10 expands or contracts and deforms, the lamp guide cover 30 is not easily deformed, and the lamp guide cover 30 can resist the deformation of the light guide plate 10, further reducing the deformable space of the light guide plate 10 and the flexible circuit board 22.

[0092] Optionally, the material of the lamp guide cover 30 includes glass fiber reinforced plastics, liquid crystal polymers, and polyphenylene sulfide.

[0093] Glass Fiber Reinforced Plastics (GFRP) is a composite material with glass fibers and their products (such as glass cloth, glass tape, glass mat, etc.) as the reinforcing material and synthetic resin as the matrix material. The hardness of glass fiber reinforced plastics depends on the content of glass fibers and the type of matrix resin. Generally speaking, the higher the content of glass fibers, the higher the hardness. Taking common glass fiber reinforced nylon with a glass fiber content of 30% and above as an example, its Shore hardness is 80HD to 100HD. The coefficient of thermal expansion of glass fiber reinforced plastics depends on the content of glass fibers and the type of matrix resin. Generally speaking, the higher the content of glass fibers, the lower the coefficient of thermal expansion. Taking common glass fiber reinforced plastics with a glass fiber content of 30%-40% as an example, its coefficient of thermal expansion is usually around (20-50)×10 -6 / ℃.

[0094] In the liquid crystal polymer (LCP), the liquid crystal phase in the molecular chain has strong order, forming a crystal morphology similar to the diamond structure, endowing it with extremely high hardness and strength. The Shore hardness of liquid crystal polymers is usually relatively high, generally around 80HD to 90HD.

[0095] Polyphenylene Sulfide (PPS) is a crystalline high-rigidity white powder polymer with high surface hardness. The Shore hardness of polyphenylene sulfide is usually 75HD to 85HD. The coefficient of thermal expansion of polyphenylene sulfide is about (50 - 70)×10 -6 / °C.

[0096] The hardness of PMMA is relatively low. The Shore hardness of PMMA is generally 70HA to 80HA. The molecular chain of PMMA is relatively flexible, and the intermolecular force is relatively weak, so its hardness is not as high as that of liquid crystal polymers, polyphenylene sulfide, and glass fiber reinforced plastics. The coefficient of linear expansion of PMMA is (50 - 90)×10 -6 / °C.

[0097] That is to say, the order of the expansion coefficients of the above several materials from small to large is LCP < glass fiber reinforced plastic < PPS < PMMA, and the order of the hardness relationship from large to small is LCP > PPS > glass fiber reinforced plastic > PMMA. Since glass fiber reinforced plastics, liquid crystal polymers, and polyphenylene sulfide have relatively high hardness and small expansion coefficients compared to PMMA, they can effectively limit the expansion of the light guide plate 10.

[0098] According to the second aspect of the present application, as Figure 6 shown, a display terminal 2 is provided, including a display panel 3 and the above-mentioned backlight module 1.

[0099] In this embodiment, as Figure 6 shown, the display terminal 2 includes a display panel 3 and a backlight module 1, and the display panel 3 and the backlight module 1 are combined as one.

[0100] In some embodiments, the display panel 3 is a non-self-luminous panel such as a liquid crystal panel. The display panel 3 is disposed in the light-emitting direction of the backlight module 1, that is, the display panel 3 is located on one side of the light-emitting surface 10a of the light guide plate 10. The display panel 3 can be bonded to the backlight module 1 through the notch glue 43.

[0101] The display panel 3 includes a display portion and a non-display portion disposed around the display portion. The display portion may be provided with a plurality of sub-pixels, and the sub-pixels may include red sub-pixels, green sub-pixels, and blue sub-pixels to achieve color display. The non-display portion may be provided with a driving circuit, such as a gate driving circuit, etc., and the driving circuit can provide driving signals for the sub-pixels.

[0102] The light emitted by the backlight module 1 can at least completely illuminate the display area of the display panel 3, thereby providing a backlight source for the entire display area. The non-display area corresponds to the border of the backlight module 1.

[0103] As Figure 6 shown, the display panel 3 includes opposite first substrate 301 and second substrate 302, and a liquid crystal layer (not shown in the figure) disposed between the first substrate 301 and the second substrate 302. The first substrate 301 is disposed on a side of the second substrate 302 away from the backlight module 1. A first polarizer 303 is disposed on a surface of the first substrate 301 away from the second substrate 302, and a second polarizer 304 is disposed on a surface of the second substrate 302 away from the first substrate 301.

[0104] The light emitted from the backlight module 1 is incident on the display panel 3. The liquid crystal molecules in the liquid crystal layer of the display panel 3 are deflected under the action of an electric field. The light transmittance corresponding to liquid crystal molecules with different deflection angles is different, thereby controlling the light transmittance of the display panel 3 and realizing the brightness control of the display screen.

[0105] The display panel 3 may include a bonding member (not shown in the figure). The bonding member is bonded and connected to the first substrate 301. The bonding member includes a chip-on-film, a printed circuit board, a flexible printed circuit board, etc. The light bar 20 of the backlight module 1 may be electrically connected to the bonding member, and the bonding member may provide power for the light bar 20, etc.

[0106] In some embodiments, the display terminal 2 may be: any product or component with a display function such as a mobile phone, a tablet computer, a television, a monitor, a notebook computer, a digital photo frame, a navigator, etc.

[0107] In the description of the present application, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more features. In the description of the present application, "a plurality of" means two or more unless otherwise specifically defined.

[0108] In the above embodiments, the descriptions of the respective embodiments have their own emphases. For parts not detailed in a certain embodiment, reference may be made to the relevant descriptions of other embodiments.

[0109] Among the embodiments, implementation manners and related technical features of the present application, they can be combined and replaced with each other without conflict.

[0110] The above are only the preferred embodiments of the present application, and do not impose any formal restrictions on the present application. However, any simple modifications, equivalent changes, and decorations made to the above embodiments based on the technical essence of the present application without departing from the content of the technical solution of the present application still fall within the scope of the technical solution of the present application.

Claims

1. A backlight module, characterized in that, Comprising: A light guide plate, including a light-emitting surface; A light bar, including a flexible circuit board and a plurality of lamp beads provided on one side of the flexible circuit board, the plurality of lamp beads corresponding to the side wall of the light guide plate, and a part of the flexible circuit board being located on the surface of the light guide plate opposite to the light-emitting surface; A light guide cover, including an upper plate and a lower plate opposite to each other, and a middle plate connecting the upper plate and the lower plate, the lower plate at least covering the flexible circuit board, the upper plate at least covering the lamp beads and the edge of the light guide plate near the lamp beads, and the expansion coefficient of the light guide cover being less than or equal to the expansion coefficient of the light guide plate.

2. The backlight module according to claim 1, wherein The surface of the flexible circuit board facing away from the light guide plate is in contact with the lower plate, the upper plate is connected to the light-emitting surface of the light guide plate, and a first adhesive layer is provided between the upper plate and the light-emitting surface of the light guide plate, and the first adhesive layer bonds the upper plate and the light guide plate.

3. The backlight module according to claim 1, wherein A second adhesive layer is provided between the flexible circuit board and the light guide plate, and the second adhesive layer bonds the light guide plate and the flexible circuit board.

4. The backlight module according to claim 3, wherein The second adhesive layer includes a plurality of spaced adhesive segments, and the adhesive segments are provided corresponding to the gaps between adjacent two of the lamp beads.

5. The backlight module according to claim 1, wherein The surfaces of the upper plate, the middle plate and the lower plate close to the lamp beads are all white.

6. The backlight module according to any one of claims 1 to 5, characterized in that, The backlight module further includes a back plate, the back plate including a bottom plate and side plates provided on the periphery of the bottom plate, the bottom plate and the side plates forming a receiving cavity, and the back plate further includes a first folded edge corresponding to the upper plate, and the first folded edge is connected to one of the side plates; Wherein, the lower plate is in contact with the bottom plate, and the upper plate is in contact with the first folded edge.

7. The backlight module according to claim 6, characterized in that The edge of the upper plate on the side away from the side plate extends beyond the edge of the first folded edge on the side away from the side plate.

8. The backlight module according to any one of claims 1 to 5, characterized in that, The hardness of the light guide cover is greater than the hardness of the light guide plate.

9. The backlight module according to any one of claims 1 to 5, characterized in that The material of the light guide cover includes glass fiber reinforced plastic, liquid crystal polymer, polyphenylene sulfide.

10. A display terminal, characterized in that, Including a display panel and the backlight module according to any one of claims 1 to 9.

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