Backlight module and display device

Abstract

The invention discloses a backlight module and a display device. The backlight module comprises a back plate (1), a diffusion plate (2) and a middle frame (3), wherein the back plate (1) and the diffusion plate (2) are oppositely arranged; the middle frame (3) is arranged along the edge of the back plate (1) and abuts against the diffusion plate (2); the light-emitting devices (4) are located on the face, facing the diffusion plate (2), of the back plate (1); the outermost light-emitting device (4) in the plurality of light-emitting devices (4) is a first light-emitting device (4a), and the light-emitting device (4) closest to the first light-emitting device (4a) in the first direction of the middle frame (3) pointing to the first light-emitting device (4a) is a second light-emitting device (4b); the distance between the first light-emitting device (4a) and the inner side wall of the middle frame (3) and the distance between the first light-emitting device (4a) and the second light-emitting device (4b) meet the following conditions: a first main light beam (4a1) emitted by the first light-emitting device (4a) to the middle frame (3) is reflected by the middle frame (3) and then is projected between projection positions of the first light-emitting device (4a) and the second light-emitting device (4b) orthographically projected on the diffusion plate (2); a second main light beam (4b1) emitted by the second light emitting device (4b) to the middle frame (3) passes through the abutting position of the middle frame (3) and the diffusion plate (2).

Description

Backlight module and display device Technical Field

[0001] The present disclosure relates to the field of display technology, and in particular to a backlight module and a display device. Background Art

[0002] Since the brightness around the display screen usually attenuates to varying degrees, a dark band of a certain width will exist near the splicing seam in the splicing screen product (as shown in Figure 1), which will greatly affect the visual effect.

[0003] However, due to the limitations of current technology, the physical seams of spliced ​​screens cannot be reduced for the time being. Therefore, how to improve the dark band around the display screen has become a technical problem that needs to be solved urgently.

[0004] Summary of the Invention

[0005] The embodiments of the present disclosure provide a backlight module and a display device to solve the above-mentioned technical problems in the prior art.

[0006] In a first aspect, to solve the above technical problems, the present disclosure provides a backlight module, comprising:

[0007] A back plate and a diffuser plate arranged opposite to each other, and a middle frame arranged along an edge area of ​​the back plate, the middle frame abutting against the diffuser plate;

[0008] a plurality of light-emitting devices located on a side of the back plate facing the diffuser; the outermost light-emitting device among the plurality of light-emitting devices is a first light-emitting device, and the light-emitting device closest to the first light-emitting device in a first direction where the middle frame points to the first light-emitting device is a second light-emitting device;

[0009] The distance between the first light-emitting device and the inner side wall of the middle frame, and the distance between the first light-emitting device and the second light-emitting device satisfy: a first main light beam emitted by the first light-emitting device toward the middle frame is reflected by the middle frame and projected so that the first light-emitting device and the second light-emitting device are directly projected between the projection positions of the diffuser plate, and a second main light beam emitted by the second light-emitting device toward the middle frame passes through the abutment position between the middle frame and the diffuser plate.

[0010] In one possible embodiment, the distance between the second light-emitting device and the inner side wall of the middle frame satisfies: at least the main light emitted by the second light-emitting device at the minimum main light-emitting angle toward the side of the first light-emitting device passes through the abutment position; or, at least the main light emitted by the second light-emitting device at the maximum main light-emitting angle toward the side of the first device passes through the abutment position.

[0011] In a possible implementation manner, the distance between the second light emitting device and the inner sidewall of the middle frame is in a range of OD / tanc2 to OD / tanb2;

[0012] OD is the distance between the back plate and the diffuser plate, b2 is the complementary angle of the maximum main light-emitting angle of the second light-emitting device, and c2 is the complementary angle of the minimum main light-emitting angle of the second light-emitting device.

[0013] In one possible implementation, a distance between the first light-emitting device and the inner sidewall of the middle frame is in a range of 1 / 3 OD / tan c1≤L1≤1 / 3 OD / tan b1, where L1 is the distance between the first light-emitting device and the inner sidewall of the middle frame; b1 is the complementary angle of the maximum main light-emitting angle of the first light-emitting device, and c1 is the complementary angle of the minimum main light-emitting angle of the first light-emitting device;

[0014] The distance between the first light emitting device and the second light emitting device has a value range of: 2 / 3 OD / tan c2≤L2≤2 / 3 OD / tan b2, where L2 is the distance between the first light emitting device and the second light emitting device.

[0015] In a possible implementation manner, the distance between the first light-emitting device and the second light-emitting device is twice the distance between the first light-emitting device and the inner side wall of the middle frame.

[0016] In one possible implementation, the middle frame has an inclined portion and a vertical portion, the vertical portion is located between the inclined portion and the back plate and contacts the back plate; the inclined portion has a first reflective slope facing the side where the first light-emitting device is located and abuts against the diffuser plate;

[0017] The inclination angle of the first reflecting bevel satisfies: at least a portion of the second main light beam is projected onto the first reflecting bevel, and the second main light beam is perpendicular to the diffuser after being reflected by the first reflecting bevel; or, the edge of the second main light beam passes through the abutment position between the first reflecting bevel and the diffuser.

[0018] In a possible implementation manner, the range of the inclination angle is: (90°-c2) / 2≤δ≤(90°-b2) / 2;

[0019] Wherein, δ is the tilt angle, c2 is the complementary angle of the minimum main luminous angle of the second light-emitting device, and b2 is the complementary angle of the maximum main luminous angle of the second light-emitting device.

[0020] In a possible implementation manner, a support surface is provided at a position where the middle frame abuts the diffuser plate, and the support surface is parallel to the diffuser plate.

[0021] In one possible embodiment, the length of the orthographic projection of the first reflecting slope on the light guide plate in the first direction satisfies: the third main light beam emitted by the first light-emitting device toward the middle frame side is projected onto the vertical part, so that the third main light beam is reflected by the vertical part and then projected onto the area on the diffuser corresponding to the area between the first light-emitting device and the second light-emitting device.

[0022] In a possible implementation manner, the length of the first reflective inclined surface in the first direction is: L4 = (OD-L1×tanc1)×tanδ;

[0023] Among them, L4 is the length of the first reflective slope in the first direction, OD is the distance between the back plate and the diffuser, L1 is the distance between the first light-emitting device and the middle frame, c1 is the complementary angle of the minimum main light-emitting angle of the first light-emitting device, and δ is the inclination angle of the first reflective slope.

[0024] In one possible implementation, the middle frame includes:

[0025] a first body located at the inclined portion, the first body having a first surface, a second surface, and a connecting structure connected in sequence to the inclined surface, the first surface intersecting the diffuser plate, the second surface being parallel to and not in contact with the diffuser plate, the inclined surface being located on a side of the first surface close to the first light-emitting device, and one end of the inclined surface abutting the diffuser plate; the connecting structure extending from the second surface toward the back plate side and being perpendicular to the second surface;

[0026] The first reflective structure is located on a side of the first body close to the first light emitting device, with a portion of the first reflective structure located on the inclined portion and another portion located on the vertical portion.

[0027] In a possible implementation manner, an end of the connecting structure away from the diffuser plate has no contact with a surface of the back plate facing the diffuser plate, and the connecting structure has a mounting hole in the first direction;

[0028] The back plate comprises:

[0029] a second body, parallel to the diffuser plate;

[0030] The frame extends along the edge of the second body toward the diffuser plate to reach the side of the connecting structure away from the first light-emitting device; the frame has a through hole penetrating the frame at a position corresponding to the mounting hole, and the connecting member passes through the through hole and is fixedly connected to the mounting hole to connect the frame and the connecting structure.

[0031] In a possible implementation manner, in the second direction where the diffuser plate points to the back plate, the frame has bent portions at both ends of the through hole, and a thread is provided in the through hole.

[0032] In a possible implementation manner, the connecting structure extends from the second surface to a surface of the back plate facing the diffuser plate and is perpendicular to the second surface;

[0033] One end of the connecting structure away from the diffusion plate abuts against the back plate, and a surface of the connecting structure away from the first reflective structure is flush with the first surface and the end surface of the diffusion plate.

[0034] In a possible implementation manner, the longitudinal cross-section of the connecting structure is L-shaped;

[0035] One end of the first portion of the L-shape perpendicular to the diffuser plate away from the second portion parallel to the diffuser plate is connected to the second surface, and the second portion is located on a side surface of the back plate close to the diffuser plate.

[0036] In one possible implementation, the back plate includes a first area and a second area surrounding the first area, and a distance between a portion of the back plate located within the first area and the diffuser plate is smaller than a distance between a portion of the back plate located within the second area and the diffuser plate.

[0037] The second portion is located in the second area, and a height of the second portion is a height difference between a portion of the back plate in the first area and a portion of the back plate in the second area.

[0038] In a possible implementation manner, the second portion further includes a protrusion, and the protrusion is located on a side surface of the second portion close to the diffuser plate.

[0039] In a possible implementation manner, the first body further includes:

[0040] The vertical structure is located on a side of the connecting structure close to the light emitting device, and a side of the vertical structure close to the light emitting device is connected to the inclined surface, and a side of the vertical structure close to the diffuser is connected to the second surface.

[0041] In a possible implementation manner, the vertical structure further has an extension portion, which extends along an end away from the diffuser plate toward the side where the first light-emitting device is located, and the extension portion is parallel to the diffuser plate and contacts a surface of the back plate close to the diffuser plate.

[0042] In a possible implementation manner, the first body further includes:

[0043] A transition structure is connected between the vertical structure and the second surface, wherein a side of the transition structure facing the first light-emitting device is connected between the inclined surface and a side of the vertical structure, and a side of the vertical structure faces the side of the first light-emitting device.

[0044] In a possible implementation manner, the backlight module further includes a reflective sheet, and the reflective sheet is located on a side of the back plate facing the diffuser plate.

[0045] In a possible implementation manner, the first body is integrally formed by an injection molding process, and the first reflective structure is a reflective film;

[0046] The first body is made of metal. The reflective sheet located on the surface of the back plate facing the diffuser extends along the surface of the first body facing the first light emitting device to the diffuser to form the first reflective structure.

[0047] In a possible implementation manner, the backlight module further includes:

[0048] A second reflective structure is fixed to a side of the back plate facing the diffuser plate and is located between the first light-emitting device and the second light-emitting device; the second reflective structure has a second reflective slope, which is used to reflect a third main beam formed by the main light emitted by the first light-emitting device to the side where the second light-emitting device is located, so that the third main beam is irradiated on the surrounding area where the middle frame and the diffuser plate are in contact, and the second reflective structure does not block the second main beam.

[0049] In a possible implementation manner, the second reflective structure further includes:

[0050] a vertical surface, the vertical surface facing the second light-emitting device and intersecting the second reflective inclined surface;

[0051] The bottom surface is located on a side of the back plate facing the diffuser plate and connects the vertical surface and the second reflective inclined surface.

[0052] In one possible embodiment, the height of the vertical surface satisfies the following requirements: a main light emitted by the first light-emitting device at a minimum main light-emitting angle toward the second reflective inclined surface reaches the diffuser after being reflected by the second reflective inclined surface, and the vertical surface does not block a main light emitted by the second light-emitting device at a maximum main light-emitting angle toward the first light-emitting device;

[0053] The included angle between the second reflective bevel and the vertical plane satisfies: the main light emitted by the first light-emitting device toward the second reflective bevel at the maximum main light-emitting angle intersects the second reflective bevel and reaches the middle frame after being reflected by the second reflective bevel.

[0054] In a possible implementation manner, the angle satisfies the following constraints: tan(180°+b1-2γ)≥(L5-H1) / (L3-L5); tan(180°+c1-2γ)≤(OD-H) / (L1+L3);

[0055] Among them, L5=L3(tanc1-tanb1) / (tanγ-tanb1); H1=L3×tanc-L3×tanγ(tanc1-tanb1) / (tanγ-tanb1);

[0056] γ is the angle, b1 is the complementary angle of the maximum main light-emitting angle of the first light-emitting device, c1 is the complementary angle of the minimum main light-emitting angle of the first light-emitting device, L1 is the distance between the first light-emitting device and the middle frame, L2 is the distance between the first light-emitting device and the second light-emitting device, L3 is the distance between the first light-emitting device and the vertical plane, the vertical plane is parallel to the center line of the first light-emitting device, H is the height of the vertical plane, and OD is the distance between the back plate and the diffuser.

[0057] In a possible implementation manner, the height of the vertical surface satisfies the following constraint relationship: H = (L2 - L3) × tanb1 = L3 × tanc1;

[0058] Wherein, H is the height of the vertical surface.

[0059] In a possible implementation manner, the second reflective structure further includes:

[0060] A plurality of fixing structures, one end of each fixing structure is connected to the bottom surface of the second reflecting structure, and the other end of each fixing structure has a hook extending in the direction of the second reflecting structure.

[0061] In a possible implementation manner, the second reflective structure and the plurality of fixing structures are integrally formed by an injection molding process.

[0062] In a second aspect, an embodiment of the present disclosure provides a display device, including:

[0063] The backlight module as described in the first aspect;

[0064] The display panel is located on the light-emitting surface of the backlight module. BRIEF DESCRIPTION OF THE DRAWINGS

[0065] FIG1 is a schematic diagram of a dark frame attached to a splicing seam of a splicing screen in the related art provided by an embodiment of the present disclosure;

[0066] FIG2 is a schematic structural diagram of a backlight module provided by an embodiment of the present disclosure;

[0067] FIG3 is a brightness curve diagram of a light emitting device provided by an embodiment of the present disclosure;

[0068] 4 and 5 are schematic diagrams showing a situation in which the main light at the edge of a second main light beam is irradiated onto the edge of a backlight module according to an embodiment of the present disclosure;

[0069] 6 to 8 are schematic diagrams of an optical path of a first main light beam provided in an embodiment of the present disclosure;

[0070] FIG9 is a schematic structural diagram of a backlight module provided in an embodiment of the present disclosure;

[0071] FIG10 is a partial enlarged view of the backlight module corresponding to the middle frame area in FIG9 provided by an embodiment of the present disclosure;

[0072] FIG11 is a mathematical model for constraining the inclination angle of a first reflecting inclined surface provided by an embodiment of the present disclosure;

[0073] FIG12 is a schematic structural diagram of a backlight module provided in an embodiment of the present disclosure;

[0074] FIG13 is a partial enlarged view of the area where the middle frame in FIG12 is located, provided by an embodiment of the present disclosure;

[0075] FIG14 is a schematic structural diagram of another backlight module provided in an embodiment of the present disclosure;

[0076] FIG15 is a schematic structural diagram of a middle frame provided in an embodiment of the present disclosure;

[0077] FIG16 is a schematic structural diagram of a backplane provided by an embodiment of the present disclosure;

[0078] FIG17 is a schematic diagram of a frame bending according to an embodiment of the present disclosure;

[0079] FIG18 is a schematic structural diagram of a middle frame and a back plate provided in an embodiment of the present disclosure;

[0080] 19 and 20 are schematic structural diagrams of another middle frame and back plate provided in an embodiment of the present disclosure;

[0081] FIG21 is a schematic structural diagram of another middle frame and back plate provided in an embodiment of the present disclosure;

[0082] FIG22 is a schematic structural diagram of another middle frame and back plate provided in an embodiment of the present disclosure;

[0083] 23 and 24 are schematic structural diagrams of a first body provided in an embodiment of the present disclosure;

[0084] FIG25 is a schematic structural diagram of another middle frame provided in an embodiment of the present disclosure;

[0085] FIG26 is a schematic structural diagram of another backlight module provided by an embodiment of the present disclosure;

[0086] FIG27 is a light path diagram of a third main light beam provided by an embodiment of the present disclosure;

[0087] FIG28 is a schematic structural diagram of a second reflective structure provided by an embodiment of the present disclosure;

[0088] FIG29 is a schematic diagram of changing the inclination angle of the first reflective inclined surface according to an embodiment of the present disclosure;

[0089] FIG30 shows a brightness curve diagram of the front and rear edges of the backlight module after optimization.

[0090] Reference Signs: Back Plate 1, Diffuser Plate 2, Middle Frame 3, Light-Emitting Device 4, First Light-Emitting Device 4a, Second Light-Emitting Device 4b, Second Reflective Structure 5, Second Reflective Inclined Surface 51, First Main Light Beam 4a1, Second Main Light Beam 4b2, Third Main Light Beam 4a2, Vertical Surface 52, Bottom Surface 53, Fixing Structure 54, First Reflective Inclined Surface 3s, First Body 31, First Reflective Structure 32, First Surface 311, Second Surface 312, Inclined Surface 313, Supporting Surface 3m, Connecting Structure 314, Second Body 11, Frame 12, Mounting Hole K, Through Hole K', Bend 121, Reflective Sheet 6, Vertical Structure 315, Transition Structure 316;

[0091] First direction X, second direction Y, minimum main luminous angle α of the first light emitting device, maximum main luminous angle β of the first light emitting device, angle γ, minimum main luminous angle α' of the second light emitting device, maximum main luminous angle β' of the second light emitting device, inclination angle δ of the first reflective slope. DETAILED DESCRIPTION

[0092] The embodiments of the present disclosure provide a backlight module and a display device to solve the above-mentioned technical problems in the prior art.

[0093] In order to make the above-mentioned purposes, features and advantages of the present disclosure more obvious and easy to understand, the present disclosure will be further described below with reference to the accompanying drawings and examples. However, the example embodiments can be implemented in various forms and should not be understood as being limited to the embodiments set forth herein; on the contrary, these embodiments are provided to make the present disclosure more comprehensive and complete, and to fully convey the concepts of the example embodiments to those skilled in the art. The same figure marks in the figures represent the same or similar structures, and their repeated descriptions will be omitted. The words expressing position and direction described in the present disclosure are all explained using the accompanying drawings as examples, but changes can be made as needed, and all changes are included in the scope of protection of the present disclosure. The drawings of the present disclosure are only used to illustrate relative position relationships and do not represent true proportions.

[0094] It should be noted that specific details are set forth in the following description to facilitate a full understanding of the present disclosure. However, the present disclosure can be implemented in a variety of ways different from those described herein, and those skilled in the art can make similar generalizations without violating the connotation of the present disclosure. Therefore, the present disclosure is not limited to the specific embodiments disclosed below. The subsequent description of the specification is a preferred embodiment of the present disclosure, but the description is for the purpose of illustrating the general principles of the present disclosure and is not intended to limit the scope of the present disclosure. The scope of protection of the present disclosure shall be as defined by the appended claims.

[0095] A backlight module and a display device provided by the embodiments of the present disclosure will be described in detail below with reference to the accompanying drawings.

[0096] FIG2 is a schematic structural diagram of a backlight module provided in an embodiment of the present disclosure. The backlight module includes:

[0097] A back plate 1 and a diffuser plate 2 are arranged opposite to each other, and a middle frame 3 is arranged along the edge area of ​​the back plate 1, and the middle frame 3 abuts against the diffuser plate 2;

[0098] Multiple light-emitting devices 4 are located on a side of the back plate 1 facing the diffuser plate 2; the outermost light-emitting device 4 among the multiple light-emitting devices 4 is a first light-emitting device 4a, and the light-emitting device 4 closest to the first light-emitting device 4a in a first direction X from the middle frame 3 to the first light-emitting device 4a is a second light-emitting device 4b;

[0099] The distance L1 between the first light-emitting device 4a and the inner wall 3a of the middle frame 3, and the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b satisfy the following requirements: the first main light beam 4a1 emitted by the first light-emitting device 4a toward the middle frame 3 is reflected by the middle frame 3 and projected so that the first light-emitting device 4a and the second light-emitting device 4b are projected directly between the projection positions of the diffuser plate 2, and the second main light beam 4b1 emitted by the second light-emitting device 4b toward the middle frame 3 passes through the abutment position between the middle frame 3 and the diffuser plate 2.

[0100] Please refer to Figure 3 for a brightness curve diagram of a light-emitting device provided in an embodiment of the present disclosure. In Figure 3, the horizontal axis represents the emission angle of light emitted by the light-emitting device 4, and the vertical axis represents the brightness of the light-emitting device 4. The maximum emission angle corresponding to half the maximum brightness is generally referred to as the maximum principal emission angle, and the minimum emission angle is referred to as the minimum principal emission angle. Light emitted at an emission angle between the minimum principal emission angle and the maximum principal emission angle is referred to as the principal light, and the beam formed by all principal light rays of a light-emitting device 4 is referred to as the principal beam. With respect to the brightness curve of the light-emitting device 4 shown in Figure 3, the maximum brightness is 76, and half the maximum brightness is 38. The minimum principal emission angle corresponding to the brightness of 38 is approximately 60°, and the maximum principal emission angle is approximately 80°. The two peaks shown in Figure 3 correspond to the two sides of the light-emitting device 4, respectively. For example, for the first light-emitting device 4a shown in Figure 2, it is assumed that the peak corresponding to the side of the first light-emitting device 4a facing the middle frame 3 is the peak of 10° to 90° shown in Figure 3, and the peak corresponding to the side of the first light-emitting device 4a facing the second light-emitting device 4b is the peak of -10° to -90° shown in Figure 3.

[0101] In this disclosure, to distinguish the main light beams emitted by the first light-emitting device 4a and the second light-emitting device 4b, the main light beam emitted by the first light-emitting device 4a toward the middle frame is referred to as the first main light beam (denoted as 4a1), the main light beam emitted by the first light-emitting device 4a toward the second light-emitting device 4b is referred to as the third main light beam (denoted as 4a2); and the main light beam emitted by the second light-emitting device 4b toward the first light-emitting device 4a (i.e., the middle frame 3) is referred to as the second main light beam (denoted as 4b1). The main light beam emitted by the light-emitting device 4 in Figure 2 generally resembles a radial trumpet shape.

[0102] As shown in FIG2 , by adjusting the distance L1 between the first light-emitting device 4a and the inner sidewall of the middle frame 3, the first main light beam 4a1 emitted by the first light-emitting device 4a toward the side of the middle frame 3 is reflected by the inner sidewall 3a of the middle frame 3 and arrives between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b on the diffuser 3. This prevents the first main light beam 4a1 from entering the area between the projection position of the first light-emitting device 4a and the abutment position of the middle frame 3 and the diffuser 2, thereby illuminating the same area with other main light beams and causing a bright band to appear in the corresponding area. At the same time, it also prevents the first main light beam 4a1 from entering the area where the projection position of the second light-emitting device 4b is away from the side of the middle frame 3, thereby causing a dark band to appear between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b.

[0103] By adjusting the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b, the second main light beam 4b1 emitted by the second light-emitting device 4b toward the side of the middle frame 3 passes through the position where the diffuser plate 2 and the middle frame 3 abut each other, thereby improving the brightness near the position where the diffuser plate 2 and the middle frame 3 abut each other (i.e., the edge of the backlight module).

[0104] Therefore, in the embodiment provided by the present disclosure, by adjusting the distance L1 between the first light-emitting device 4a and the inner side wall 3a of the middle frame 3, and adjusting the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b, the second main light beam 4b1 passes through the abutment position between the middle frame 3 and the diffuser 2, so that the second main light beam 4b1 emitted by the second light-emitting device 4b to the side of the first light-emitting device 4a (also the middle frame 3) can be irradiated to the edge of the backlight module, thereby improving the brightness of the edge of the backlight module; and the first main light beam 4a1 emitted to the side of the middle frame 3 can be reflected by the inner side wall 3a of the middle frame 3 and projected between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b on the diffuser 3, so as to prevent the appearance of bright bands and dark bands at the edge of the backlight module, thereby effectively improving the uniformity of the brightness at the edge of the backlight module, and effectively improving the dark frame at the edge of the backlight module.

[0105] Please refer to Figures 4 and 5 for schematic diagrams of an embodiment of the present disclosure providing a main light beam at the edge of a second main beam irradiating the edge of a backlight module. The distance (L1+L2) between the second light-emitting device 4b and the inner side wall 3a of the middle frame 3 satisfies: as shown in Figure 4, at least the main light emitted by the second light-emitting device 4b to the side of the first light-emitting device 4a at the minimum main emitting angle α' passes through the abutment position, so that the edge of the second main beam 4b1 passes through the edge of the backlight module while the second main beam 4b2 irradiates the middle frame 3 near the abutment position, so that the inner side wall 3a of the middle frame 3 can reflect the second main beam 4b1 to the edge of the diffuser plate 2, thereby improving the brightness of the edge of the backlight module; or, as shown in Figure 5, at least the main light emitted by the second light-emitting device 4b to the side of the first device at the maximum main emitting angle β' passes through the abutment position, so that the second main beam 4b1 can directly irradiate the edge of the diffuser plate 2 until the abutment position with the middle frame 3, thereby improving the brightness of the edge of the backlight module.

[0106] In the embodiment provided in the present disclosure, by controlling the distance (L1+L2) between the second light-emitting device 4b and the inner wall 3a of the middle frame 3, at least the light emitted by the second light-emitting device 4b to the first light-emitting device 4a side at the minimum main light-emitting angle α' passes through the abutment position, or the light emitted to the first device side at the maximum main light-emitting angle β' passes through the abutment position, it can be ensured that at least the main light at the edge of the second main light beam 4b1 passes through the abutment position between the middle frame 3 and the diffuser plate 2, thereby effectively improving the brightness of the edge of the backlight module and improving the dark frame.

[0107] Continuing to refer to FIG. 4 and FIG. 5 , the distance ( L1 + L2 ) between the second light emitting device 4 b and the inner sidewall 3 a of the middle frame 3 is in the range of OD / tanc2 to OD / tanb2;

[0108] Wherein, OD is the distance between the back plate 1 and the diffuser plate 2, b2 is the complementary angle of the maximum main luminous angle β' of the second light-emitting device 4b (i.e., b2 = 90°-β'), and c2 is the complementary angle of the minimum main luminous angle α' of the second light-emitting device 4b (i.e., c2 = 90°-α').

[0109] In the embodiment provided in the present disclosure, by setting the range of the distance (L1+L2) between the second light-emitting device 4b and the inner wall 3a of the middle frame 3 to OD / tanc2~OD / tanb2, it can be ensured that the second main light beam 4b1 emitted by the second light-emitting device 4b to the side of the middle frame 3 passes through the abutment position between the middle frame 3 and the diffuser plate 2, thereby improving the edge brightness of the backlight module and improving the edge dark frame.

[0110] In some embodiments, the distance L1 between the first light-emitting device 4a and the inner sidewall 3a of the middle frame 3 is in the range of 1 / 3 OD / tan c1≤L1≤1 / 3 OD / tan b1; L1 is the distance between the first light-emitting device and the inner sidewall of the middle frame; wherein b1 is the complementary angle of the maximum main light-emitting angle β of the first light-emitting device (i.e., b1=90°-β), and c1 is the complementary angle of the minimum main light-emitting angle α of the first light-emitting device (i.e., c1=90°-α);

[0111] The distance L2 between the first light emitting device 4a and the second light emitting device 4b has a value range of: 2 / 3 OD / tan c2≤L2≤2 / 3 OD / tan b2; L2 is the distance between the first light emitting device and the second light emitting device.

[0112] The first light-emitting device 4a and the second light-emitting device 4b can be light-emitting devices with the same main light-emitting angle, in which case α = α' (corresponding c1 = c2), β = β' (corresponding b1 = b2); the first light-emitting device 4a and the second light-emitting device 4b can also be light-emitting devices with different main light-emitting angles, in which case α≠α' (corresponding c1≠c2), β≠β' (corresponding b1≠b2).

[0113] In the embodiment provided by the present disclosure, by setting the value range of the distance L1 between the first light-emitting device 4a and the inner side wall 3a of the middle frame 3 to 1 / 3 OD / tan c1≤L1≤1 / 3 OD / tan b1; wherein b1 is the complementary angle of the maximum main light-emitting angle β of the first light-emitting device, and c1 is the complementary angle of the minimum main light-emitting angle α of the first light-emitting device; and setting the value range of the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b to: 2 / 3 OD / tan c2≤L2≤2 / 3 OD / tan b2, the first main light beam 4a1 can be reflected by the inner side wall 3a of the middle frame 3 and projected between the projection position of the first light-emitting device 4a and the projection position of the second light-emitting device 4b, and the main light in the second main light beam 4b1 can pass through the abutment position between the diffuser 2 and the middle frame 3.

[0114] Please refer to Figures 6 to 8, which are schematic diagrams of the optical path of a first main light beam provided in an embodiment of the present disclosure.

[0115] As shown in FIG6 , if L2>2L1, then after the first main light beam 4a1 is reflected by the inner wall 3a of the middle frame 3, at least a portion of the first main light beam 4a1 is located on the side of the projection position of the second light-emitting device 4b away from the middle frame 3, resulting in a dark area in the area between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b.

[0116] As shown in FIG7 , if L2<2L1, then after the first main light beam 4a1 is reflected by the inner wall 3a of the middle frame 3, at least a portion of the first main light beam 4a1 is located in the area between the projection position of the first light-emitting device 4a and the middle frame 3, so that there is a bright area in the area between the projection position of the first light-emitting device 4a and the middle frame 3.

[0117] As shown in Figure 8, the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b is twice the distance L1 between the first light-emitting device 4a and the inner sidewall 3b of the middle frame 3, that is, L2 = 2L1. At this time, the first main light beam 4a1 emitted by the first light-emitting device 4a toward the middle frame 3 is reflected by the inner sidewall 3a of the middle frame 3 to the area of ​​the diffuser 2 where the first light-emitting device 4a and the second light-emitting device 4b are projected. This ensures that there is no dark area between the projected positions of the first light-emitting device 4a and the second light-emitting device 4b, and no bright area between the first light-emitting device 4a and the middle frame 3.

[0118] Therefore, in the embodiment provided in the present disclosure, by setting the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b to twice the distance L2 between the first light-emitting device 4a and the inner wall of the middle frame 3, not only can it be ensured that there is no dark area between the first light-emitting device 4a and the second light-emitting device 4b, but the brightness of the edge area of ​​the backlight module can also be made uniform.

[0119] Please refer to Figures 9 and 10. Figure 9 is a schematic diagram of the structure of a backlight module provided in an embodiment of the present disclosure, and Figure 10 is an enlarged partial view of the backlight module corresponding to the middle frame region in Figure 9, provided in an embodiment of the present disclosure. As shown in Figure 9, the middle frame 3 has an inclined portion and a vertical portion. The vertical portion is located between the inclined portion and the backplate 1 and contacts the backplate 1. The inclined portion has a first reflective bevel 3s facing the side where the first light-emitting device 4a is located and abuts the diffuser 2. The first reflective bevel 3s is a portion of the inner sidewall 3a of the middle frame 3 located in the inclined portion.

[0120] As shown in Figure 10, the inclination angle δ of the first reflecting bevel 3s satisfies: the second main light beam 4b1 is at least partially projected onto the first reflecting bevel 3s, and the second main light beam 4b1 is perpendicular to the diffuser plate 2 after being reflected by the first reflecting bevel 3s; or, the edge of the second main light beam 4b1 passes through the abutment position between the first reflecting bevel 3s and the diffuser plate 2.

[0121] In the embodiment provided in the present disclosure, by allowing the second main light beam 4b1 emitted by the second light-emitting device 4b to the side of the middle frame 3 to be at least partially projected onto the first reflective bevel 3s, and the second main light beam 4b1 is perpendicular to the diffuser plate 2 after being reflected by the first reflective bevel 3s; or by allowing the edge of the second main light beam 4b1 to pass through the abutment position between the first reflective bevel 3s and the diffuser plate 2, the second main light beam 4b1 can be illuminated to the edge area of ​​the diffuser plate 2, thereby improving the brightness of the edge area of ​​the backlight module.

[0122] Please refer to FIG11 for a mathematical model for constraining the inclination angle of the first reflecting slope 3s provided in an embodiment of the present disclosure.

[0123] In Figure 11 , it is assumed that the main light ray emitted by the second light-emitting device 4b toward the middle frame 3 has an exit angle of (90°-e), where e is the complementary angle of the main light ray's exit angle. When this main light ray reaches the first reflective bevel 3s, it is reflected by the first reflective bevel 3s toward the diffuser 2 and enters the diffuser 2 at an angle perpendicular to the diffuser 2. Therefore, the inclination angle of the first reflective bevel 3s can be determined to be δ = (90°-e) / 2, and α' ≤ (90°-e) ≤ β', so α' / 2 ≤ δ ≤ β' / 2.

[0124] The range of the inclination angle of the first reflecting inclined surface 3s can also be expressed as: (90°-c2) / 2≤δ≤(90°-b2) / 2;

[0125] Among them, δ is the inclination angle of the first reflecting slope 3s, c2 is the complementary angle of the minimum main luminous angle α' of the second light-emitting device 4b (i.e. c2 = 90°-α'), and b2 is the complementary angle of the maximum main luminous angle β' of the second light-emitting device 4b (i.e. b2 = 90°-β').

[0126] In the embodiment provided in the present disclosure, by setting the inclination angle of the first reflective bevel 3s of the middle frame 3 within (90°-c2) / 2≤δ≤(90°-b2) / 2, the second main light beam 4b1 can be at least partially projected onto the first reflective bevel 3s, and the second main light beam 4b2 is perpendicular to the diffuser plate 2 after being reflected by the first reflective bevel 3s; or, the edge of the second main light beam 4b2 passes through the abutment position between the first reflective bevel 3s and the diffuser plate 2.

[0127] Please refer to Figures 12 and 13. Figure 12 is a structural schematic diagram of a backlight module provided in an embodiment of the present disclosure. Figure 13 is a partial enlarged view of the area where the middle frame in Figure 12 is located provided in an embodiment of the present disclosure.

[0128] The middle frame 3 has a support surface 3 m at a position where it contacts the diffuser plate 2 . The support surface 3 m is parallel to the diffuser plate 2 .

[0129] The length of the support surface 3m in the first direction X is d, and 1mm≤d≤1.5mm.

[0130] In the implementation provided by the present disclosure, by providing a support surface 3m at the position where the middle frame 3 and the diffuser plate 2 abut against each other, the middle frame 3 and the diffuser plate 2 can be easily assembled, thereby improving production efficiency.

[0131] Please refer to FIG14 which is a schematic structural diagram of another backlight module provided in an embodiment of the present disclosure.

[0132] The length L4 of the orthographic projection of the first reflecting slope 3s on the diffuser plate 2 in the first direction X satisfies the following conditions: the first main light beam 4a1 emitted by the first light-emitting device 4a toward the side of the middle frame 3 is projected onto the vertical portion of the middle frame 3, so that the first main light beam 4a1 is reflected by the vertical portion and projected onto the area between the center of the diffuser plate 2 and the projection position of the first light-emitting device and the projection position of the second light-emitting device 4b.

[0133] In the embodiment provided in the present disclosure, by controlling the length L4 of the positive projection of the first reflective slope 3s on the diffuser plate 2 in the first direction X, it is satisfied that: the first main light beam 4a1 emitted by the first light-emitting device 4a to the side of the middle frame 3 is projected on the vertical part of the middle frame 3, so that the first main light beam 4a1 is reflected by the vertical part and projected on the diffuser plate 2 between the projection position of the first light-emitting device 4a and the projection position of the second light-emitting device 4b. This can prevent the occurrence of a dark area in the area between the projection position of the first light-emitting device 4a and the projection position of the second light-emitting device 4b, or the occurrence of a bright area in the area between the projection position of the first light-emitting device 4a and the middle frame 3, thereby improving the brightness uniformity of the backlight module in the edge area.

[0134] Continuing to refer to FIG. 14 , the length of the first reflective inclined surface 3s in the first direction X is: L4 = (OD-L1×tanc1)×tanδ;

[0135] Among them, L4 is the length of the first reflective bevel 3s in the first direction X, OD is the distance between the back plate 1 and the diffuser 2, L1 is the distance between the first light-emitting device 4a and the inner side wall 3a of the middle frame 3, c1 is the complementary angle of the minimum main light-emitting angle α of the first light-emitting device 4a (i.e., c1 = 90°-α), and δ is the inclination angle of the first reflective bevel 3s.

[0136] Please refer to Figure 15 for a structural diagram of a middle frame provided in an embodiment of the present disclosure.

[0137] The middle frame 3 includes:

[0138] The first body 31 is located at the inclined portion and has a first surface 311, a second surface 312, an inclined surface 313, and a connecting structure 314, which are sequentially connected. The first surface 311 intersects with the diffuser plate 2, and the second surface 312 is parallel to and does not contact the diffuser plate 2. The inclined surface 313 is located on the side of the first surface 311 close to the first light-emitting device 4a, and one end of the inclined surface 313 abuts the diffuser plate 2. The connecting structure 314 extends from the second surface 312 toward the back plate 1 and is perpendicular to the second surface 312.

[0139] The first reflective structure 32 is located on the side of the first body 31 close to the first light emitting device 4a. The second reflective structure 32 is partially located in the inclined portion and the other part is located in the vertical portion. The side of the first reflective structure 32 close to the first light emitting device 4a is the inner sidewall 3a of the middle frame 3.

[0140] The first surface 311 may be perpendicular to the second surface 312 , or may form an obtuse angle with the second surface 312 .

[0141] 14 and 15 , the end of the connection structure 314 away from the diffuser plate 2 is not in contact with the surface of the back plate 1 facing the diffuser plate 2 , and the connection structure 314 has a mounting hole K in the first direction X;

[0142] FIG16 is a schematic structural diagram of a backplane according to an embodiment of the present disclosure. The backplane 1 includes:

[0143] The second body 11 is parallel to the diffuser plate 2;

[0144] The frame 12 extends along the edge of the second body 11 toward the diffuser plate 2 to reach the side of the connecting structure 314 away from the first light-emitting device 4a; the frame 12 has a through hole K' that penetrates the frame 12 at a position corresponding to the mounting hole K, and the connecting member passes through the through hole K' and is fixedly connected to the mounting hole K to the frame 12 and the connecting structure 314.

[0145] In this solution, the first reflective structure 32 can be a metal reflective structure, such as a reflective sheet, which is attached to the surface of the first body 31 facing the first light emitting device 4 a and extends toward the second body 11 until it contacts the second body 11 .

[0146] In the embodiment provided in the present disclosure, a connecting structure 314 is provided on the first body 31 of the middle frame 3 so that the body of the middle frame 3 is not in contact with the second body 11 of the back plate 1. The size of the first body 31 can be made smaller, and the frame 12 is provided as the second body 11 and the frame 12 extending toward the diffuser 2 along the edge of the second body 11. A mounting hole K connected to the frame 12 of the back plate 1 is provided on the connecting structure 314, and a through hole K' corresponding to the mounting hole K is provided on the frame 12 of the back plate 1. Thus, the first body 31 of the middle frame 3 and the frame 12 of the back plate 1 can be fixed together by a connecting member, thereby effectively reducing the difficulty of manufacturing the first body 31, and the frame 12 of the back plate 1 can be used to support the first body 31 of the middle frame 3, thereby improving the supporting strength between the back plate 1 and the diffuser 2.

[0147] Please refer to Figure 17 for a schematic diagram of a frame bending provided in an embodiment of the present disclosure.

[0148] In the second direction Y from the diffuser plate 2 to the back plate 1 , the frame 12 has bent portions 121 at both ends of the through hole K′, and a thread is disposed in the through hole K′.

[0149] In the embodiment provided by the present disclosure, by providing bent portions 121 at both ends of the through hole K', the depth of the through hole K' can be increased, and threads can be provided on the inner wall of the through hole K'. This not only allows the connecting piece connecting the frame body 12 and the middle frame 3 to use threads without the need for nuts, thereby facilitating assembly and improving production efficiency; it also reduces the depth of the middle frame 3 intruding into the display area of ​​the backlight module.

[0150] FIG18 is a schematic diagram of the structure of a middle frame and a back plate according to an embodiment of the present disclosure. The connecting structure 314 extends from the second surface 312 to the side of the back plate 1 facing the diffuser plate 2 and is perpendicular to the second surface 312.

[0151] One end of the connection structure 314 away from the diffuser plate 2 abuts against the back plate 1 , and a surface of the connection structure 314 away from the first reflective structure 32 is flush with the first surface 311 and the end surface of the diffuser plate 2 .

[0152] As shown in Figure 18, the connecting structure 314 can be vertical. Since the connecting structure 314 is perpendicular to the second surface 312, and the second surface 312 is parallel to the diffuser 2 and the back plate 1, the connecting structure 314 is perpendicular to the diffuser 2 and the back plate 1. Since the side of the connecting structure 314 away from the first reflective structure 32 is flush with the first surface 311 and the end surface of the diffuser 2, the side of the connecting structure 314 away from the first reflective structure 32 can be regarded as the first surface 311 extending toward the back plate 1, that is, the first surface 311 is perpendicular to the diffuser 2. In this way, the inclined portion of the first body 31 in the middle frame 3 can provide the first reflective structure 32 with the inclined surface 313 required for the first reflective inclined surface 3s, and can provide support for the inclined portion in the vertical portion, so that the first body 31 can effectively support the back plate 1 and the diffuser 2, so that there is no need to set a frame 12 on the edge of the back plate 1 to support the middle frame 3, and there is no need to set a mounting hole K on the connecting structure 314, which can effectively simplify the process and improve production efficiency.

[0153] Please refer to Figures 19 and 20 for structural schematic diagrams of another middle frame and back plate provided in an embodiment of the present disclosure.

[0154] The longitudinal cross-section of the connecting structure 314 is L-shaped;

[0155] One end of the L-shaped first portion 314 a perpendicular to the diffuser plate 2 away from the second portion 314 b parallel to the diffuser plate 2 is connected to the second surface 312 . The second portion 314 b is located on one side of the back plate 1 close to the diffuser plate 2 .

[0156] As shown in Figure 19, the sides of the first part 314a and the second part 314b away from the diffuser plate 2 can both be located on the side of the back plate 1 close to the diffuser plate 2; as shown in Figure 20, there can be a height difference between the sides of the first part 314a and the second part 314b away from the diffuser plate 2, wherein the side of the second part 314b away from the diffuser plate 2 is in contact with the side of the back plate 1 close to the diffuser plate 2, and the side of the first part 314a away from the diffuser plate 2 is flush with the side of the back plate 1 away from the diffuser plate 2.

[0157] In the embodiment provided in the present disclosure, by setting the longitudinal cross-sectional figure of the connecting structure 314 to be L-shaped; and allowing the first part 314a perpendicular to the diffuser plate 2 in the L-shape to be connected to the second surface 312 at one end away from the second part 314b parallel to the diffuser plate 2, the second part 314b is located on the side surface of the back plate 1 close to the diffuser plate 2, so as to facilitate improving the supporting force of the first body 31 on the back plate 1 and the diffuser plate 2, and facilitate fixing the connecting mechanism and the back plate 1.

[0158] Please refer to Figure 21 for a structural diagram of another middle frame and back panel provided in an embodiment of the present disclosure.

[0159] The back plate 1 includes a first area A and a second area B surrounding the first area A. The distance h between the portion of the back plate 1 located in the first area A and the diffuser 2 is smaller than the distance h' between the portion of the back plate 1 located in the second area B and the diffuser 2.

[0160] The second portion is located in the second area B, and the height of the second portion is the height difference between the portion of the back plate 1 in the first area A and the portion in the second area B.

[0161] By setting the back panel 1 to include a first area A and a second area B surrounding the first area A, and making the distance h between the part of the back panel 1 located in the first area A and the diffuser 2 smaller than the distance h' between the part of the back panel 1 located in the second area B and the diffuser 2; at the same time, setting the second part in the connection structure 314 of the middle frame 3 in the second area B of the back panel 1, and making the height of the second part the height difference between the part of the back panel 1 in the first area A and the part in the second area B, the second part and the side of the part of the back panel 1 located in the first area A facing the diffuser 2 can be located in the same plane. In this way, when a reflective sheet 6 is set on the surface of the back panel 1 and the reflective sheet 6 is bent and extended toward the side of the diffuser 2 to be reused as the first reflective structure 32 of the middle frame 3, the flatness of the reflective sheet 6 on the surface of the back panel 1 can be improved, so that the light reflected by the reflective sheet 6 is more uniform.

[0162] It should be understood that FIG21 does not show the light-emitting device 4. In actual applications, the reflective sheet 6 may not be provided at the location where the light-emitting device 4 is installed. That is, a through groove may be provided in the reflective sheet 6 at the location corresponding to the light-emitting device 4 to expose the light-emitting device 4. In addition, FIG21 is a cross-sectional view, so the second region B appears to be located on both sides of the first region A. In reality, the second region B surrounds the first region.

[0163] Please refer to Figure 22 for a structural diagram of another middle frame and back panel provided in an embodiment of the present disclosure.

[0164] The second portion 314b of the connection structure 314 further includes a protrusion 314c located on a side surface of the second portion 314b close to the diffuser 2 . An end of the protrusion 314c away from the light emitting device 4 is spaced apart from the first portion 314a .

[0165] The light-emitting device 4 typically includes a circuit board, a lamp bead, and a lens. The lamp bead is disposed on the side of the circuit board facing the diffuser plate 2, and the lens is mounted on the light-emitting side of the lamp bead. Typically, multiple light emitters are mounted on a light bar. A lamp body comprises a circuit board, multiple lamp beads, and lenses corresponding to the lamp beads. Multiple light bars are mounted on the back panel 1 to form a backlight source. However, the thickness of the circuit board is generally higher than that of the reflective sheet 6. Therefore, the present disclosure provides a raised portion 314c on the surface of the second portion 314b near the diffuser plate 2, so that the thickness of the raised portion 314c is the same as that of the circuit board. This prevents the portion of the reflective sheet 6 parallel to the diffuser plate 2 from warping at the edge, keeps it in one plane, and further improves the uniformity of light reflected by the reflective sheet 6.

[0166] Please refer to Figures 23 and 24 for a structural schematic diagram of a first body provided in an embodiment of the present disclosure.

[0167] The first body 31 further includes:

[0168] The vertical structure 315 is located on the side of the connecting structure 314 near the light-emitting device 4. The side of the vertical structure 315 near the light-emitting device 4 is connected to the inclined surface 313, and the side of the vertical structure 315 near the diffuser 2 is connected to the second surface 312. It is located in the vertical portion of the middle frame 3. As shown in Figure 23, the side of the vertical structure 315 near the back panel 1 can be attached to the back panel 1; as shown in Figure 24, the side of the vertical structure 315 near the back panel 1 can also be connected to the second portion of the connecting structure 314.

[0169] In the embodiment provided herein, a vertical structure 315 is provided on the side of the connecting structure 314 near the light-emitting device 4. The side of the vertical structure 315 near the light-emitting device 4 is connected to the inclined surface 313, while the side of the vertical structure 315 near the diffuser 2 is connected to the second surface 312. This improves the stability of the first body 31. Furthermore, a reflective material can be coated on the side where the vertical portion connects to the inclined surface 313, and on the inclined surface 313 to form the first reflective structure 32. This eliminates the need to bend the reflective sheet 6, thereby reducing process complexity and improving production efficiency.

[0170] Continuing with FIG. 24 , the first body 31 further includes:

[0171] The transition structure 316 is connected between the vertical structure 315 and the second surface 312. The surface of the transition structure 316 facing the first light-emitting device 4a is connected between the inclined surface 313 and the surface of the vertical structure 315 facing the first light-emitting device 4a. The surface of the transition structure 316 facing the first light-emitting device 4a can be an arcuate transition surface, which facilitates smooth transition of light at the intersection of the vertical portion and the inclined portion, effectively improving light uniformity.

[0172] Please refer to Figure 25 for a schematic diagram of the structure of another middle frame provided in an embodiment of the present disclosure. The vertical structure 315 further includes an extension portion 315a, which extends from the end away from the diffuser plate 2 toward the side where the first light-emitting device 4a is located. The extension portion 315a is parallel to the diffuser plate 2 and contacts the side of the back plate 1 closest to the diffuser plate 2.

[0173] By providing an extension portion 315 a at one end of the vertical structure 315 close to the back plate 1 , the vertical structure 315 can be better supported when the connecting structure 314 is connected to the frame 12 of the back plate 1 , thereby improving the stability of the middle frame 3 .

[0174] Continuing with Figure 25 , the backlight module further includes a reflective sheet 6, which is located on the side of the back plate 1 facing the diffuser plate 2. In Figure 25 , a reflective material is coated on the inner sidewall of the middle frame 3 formed by the connection of the vertical structure 315 and the inclined surface 313 to form a reflective film, which constitutes the first reflective structure 32.

[0175] In some embodiments, the first body 31 is integrally formed using an injection molding process, and the first reflective structure 32 is a reflective film; forming the first body 31 using injection molding as an integral unit facilitates the manufacture of the first body 31 and is easy to form complex shapes.

[0176] The first body 31 is made of metal. The reflective sheet 6 on the surface of the back plate 1 facing the diffuser 2 extends along the surface of the first body 31 facing the first light emitting device 4 a to the diffuser 2 to form a first reflective structure 32 .

[0177] Please refer to FIG26 for a structural diagram of another backlight module provided by an embodiment of the present invention. The backlight module further includes:

[0178] The second reflective structure 5 is fixed to the side of the back plate 1 facing the diffuser plate 2 and is located between the first light-emitting device 4a and the second light-emitting device 4b; the second reflective structure 5 has a second reflective bevel 51, which is used to reflect the third main light beam 4a2 formed by the main light emitted by the first light-emitting device 4a to the side where the second light-emitting device 4b is located, so that the third main light beam 4a2 is irradiated on the surrounding area where the middle frame 3 and the diffuser plate 2 are in contact, and the second reflective structure 5 does not block the second main light beam 4b1 emitted by the second light-emitting device 4b to the side of the first light-emitting device 4a.

[0179] As shown in FIG26 , when the first light-emitting device 4a transmits the third main light beam 4a2 toward the second light-emitting device 4b, it is reflected by the second reflective bevel 51 of the second reflective structure 5 and then illuminates the surrounding area where the middle frame 3 and the diffuser plate 2 abut. This improves the brightness of the surrounding area where the middle frame 3 and the diffuser plate 2 abut (i.e., the edge area of ​​the backlight module), thereby improving the dark band at the edge of the backlight module. When the backlight module is used as a splicing screen, since the dark band at the edge of the backlight module is improved, the dark band at the splicing position of the splicing screen can also be improved. In addition, because the second reflective structure 5 does not block the second main light beam 4b1 emitted by the second light-emitting device 4b toward the first light-emitting device 4a, the second main light beam 4b1 can smoothly reach the diffuser plate 2 without the formation of a shadow area, thereby effectively improving the display effect.

[0180] Please continue to refer to FIG26 , the second reflective structure 5 further includes:

[0181] a vertical surface 52, the vertical surface 52 facing the second light emitting device 4b and intersecting the second reflective inclined surface 51;

[0182] The bottom surface 53 is located on the side of the back plate 1 facing the diffuser plate 2 and connects the vertical surface 52 and the second reflective inclined surface 51 .

[0183] The vertical surface 52 of the second reflective structure 5 is non-reflective, which can reduce the reflection of light. The second reflective bevel 51 can reflect light by coating it with a reflective material, or by attaching a reflective film layer to the second reflective bevel 51. There is no specific limitation.

[0184] Please refer to Figure 27 for a light path diagram of a third main light beam provided in an embodiment of the present disclosure.

[0185] The height H of the vertical surface 52 of the second reflective structure 5 satisfies the following requirements: the main light emitted by the first light-emitting device 4a at the minimum main light-emitting angle α toward the second reflective inclined surface 51 reaches the diffuser 2 after being reflected by the reflective surface, and the vertical surface 52 does not block the second main light beam 4b1 emitted by the second light-emitting device 4b at the maximum main light-emitting angle β' toward the side of the first light-emitting device 4a;

[0186] The included angle γ between the second reflective slope 51 of the second reflective structure 5 and the vertical surface 52 satisfies the following requirement: the main light emitted by the first light-emitting device 4a at the maximum main emission angle β toward the second reflective slope 51 intersects the second reflective slope 51 and, after being reflected by the reflective surface, reaches the middle frame 3. In the extreme case, the intersection point of the main light emitted by the first light-emitting device 4a at the maximum main emission angle β toward the reflective surface and the second reflective slope 51 of the second reflective structure 5 is exactly the intersection point of the second reflective slope 51 of the second reflective structure 5 and the vertical surface 52.

[0187] In the embodiment provided by the present disclosure, the height H of the vertical surface 52 of the second reflective structure 5 is set to satisfy: the main light emitted by the first light emitting device 4a at the minimum main light emitting angle α toward the second reflective inclined surface 51 reaches the diffuser 2 after reflection by the second reflective inclined surface 51; and the angle γ between the second reflective inclined surface 51 and the vertical surface 52 of the second reflective structure 5 satisfies: the main light emitted by the first light emitting device 4a at the maximum main light emitting angle β toward the second reflective inclined surface 51 reaches the middle frame 3 after reflection by the second reflective inclined surface 51, so that The third main light beam 4a2 emitted by the first light-emitting device 4a toward the second reflective slope 51 is reflected by the second reflective structure 5 and illuminates the surrounding area where the middle frame 3 and the diffuser plate 2 abut, further improving the brightness of the surrounding area where the middle frame 3 and the diffuser plate 2 abut; and the vertical surface 52 does not block the second main light beam 4b1 emitted by the second light-emitting device 4b at the maximum main light-emitting angle β' toward the side of the first light-emitting device 4a, so that the second main light beam emitted by the second light-emitting device 4b toward the side of the first light-emitting device 4a will not be blocked by the second reflective structure 5, thereby preventing the formation of a shadow area.

[0188] Continuing with Figure 27, the angle γ satisfies the following constraints: tan(180°+b1-2γ)≥(L5-H1) / (L3-L5); tan(180°+c1-2γ)≤(OD-H) / (L1+L3);

[0189] Among them, L5=L3(tanc1-tanb1) / (tanγ-tanb1); L5 is the distance from the intersection of the main light emitted by the first light-emitting device 4a to the second reflective structure 5 at the maximum main light-emitting angle β and the second reflective bevel 51 to the vertical surface 52; H1=L3×tanc-L3×tanγ(tanc1-tanb1) / (tanγ-tanb1); H1 is the distance from the intersection of the main light emitted by the first light-emitting device 4a to the second reflective structure 5 at the maximum main light-emitting angle β and the second reflective bevel 51 to the back panel 1.

[0190] γ is the included angle, b1 is the complementary angle of the maximum main light-emitting angle β of the first light-emitting device 4a (i.e., b1 = 90°-β), c1 is the complementary angle of the minimum main light-emitting angle α of the first light-emitting device 4a (i.e., c1 = 90°-α), L1 is the distance between the first light-emitting device 4a and the middle frame 3, L2 is the distance between the first light-emitting device 4a and the second light-emitting device 4b, L3 is the distance between the first light-emitting device 4a and the vertical surface 52, the vertical surface 52 is parallel to the center line of the first light-emitting device 4a, H is the height of the vertical surface 52, and OD is the distance between the back plate 1 and the diffuser plate 2.

[0191] The height H of the vertical surface 52 satisfies the following constraint relationship: H = (L2 - L3) × tanb1 = L3 × tanc1;

[0192] Here, H is the height of the vertical surface 52 (ie, the height of the second reflective structure 5 ).

[0193] The second reflective structure 5 can be fixed to the back panel 1 by bonding, or by providing a through hole K' on the back panel 1, providing a screw hole on the side where the bottom surface 53 of the second reflective structure 5 is located, and fixing the second reflective structure 5 to the back panel 1 by screws.

[0194] Please refer to FIG. 28 , which is a schematic structural diagram of a second reflective structure provided in an embodiment of the present disclosure. The second reflective structure 5 further includes:

[0195] A plurality of fixing structures 54 are provided, one end of the fixing structure 54 is connected to the bottom surface 53 of the second reflective structure 5 , and the other end of the fixing structure 54 has a hook extending toward the direction of the second reflective structure 5 .

[0196] The fixing structure 54 may be of a snap-fit ​​type.

[0197] By disposing a plurality of fixing structures 54 on the bottom surface 53 of the second reflective structure 5 and providing the fixing structure 54 with a hook extending toward the second reflective structure 5 at one end away from the second reflective structure 5 , the second reflective structure 5 can be easily fixed on the back plate 1 .

[0198] In some embodiments, the second reflective structure 5 and the plurality of fixing structures 54 are integrally formed using an injection molding process, which facilitates the production of the second reflective structure 5 .

[0199] Example 1

[0200] The tilt angle of the middle frame 3 in an existing backlight module was optimized. The backlight module's light mixing distance (i.e., the distance between the backplate 1 and the diffuser 2) was OD = 30 mm, the distance L1 between the first light-emitting device 4a and the inner wall of the middle frame 3 was 32 mm, and the center distance L2 between the first light-emitting device 4a and the second light-emitting device 4b was 60.5 mm. The brightness curve of the light-emitting device 4 used in the backlight module is shown in FIG3 . In the original solution, the tilt angle δ of the first reflective slope 3s of the backlight module was 61°. Now, the scheme of changing the inclination angle δ of the first reflective bevel 3s provided by the present disclosure is adopted. According to FIG3 , the minimum main luminous angle of the light-emitting device 4 is 60°, and the maximum main luminous angle is 80°, that is, α=α'=60°, β=β'=80°. According to the range formula of the inclination angle δ of the first reflective bevel 3s mentioned above, it can be determined that the value range of δ is 31.5°≤δ≤42°. δ is changed from 61° in the original scheme to 35°, as shown in FIG29 , which is a schematic diagram of changing the inclination angle of the first reflective bevel provided by the present disclosure. After optimization using the scheme provided by the present disclosure, by measuring the brightness within 80mm of the edge of the backlight module, the brightness drop point of the edge drops from the original 15mm from the edge to 5mm, as shown in FIG30 , which is a brightness curve diagram of the edge before and after optimization of the backlight module.

[0201] When the optimized backlight module is used to form a spliced ​​screen, the dark frame at the edge of the splicing seam is improved, and long-distance viewing will not affect the visual splicing seam.

[0202] Example 2

[0203] On the basis of Example 1, a second reflective structure 5 is further added between the first light-emitting device 4a and the second light-emitting device 4b. According to the above solution provided by the present disclosure, the parameters of the modified backlight module are OD=30mm, L1=37mm, L2=60.5mm, the height H of the second reflective structure 5=6.6mm, the distance L3 between the vertical surface 52 of the second reflective structure 5 and the center of the first light-emitting device 4a=20.3, and the inclination angle (i.e., the first angle) γ of the second reflective inclined surface 51 of the reflective structure is 5°. By using Lighttools software to simulate Example 1 and Example 2, it can be determined that: the brightness of the solution of Example 1 begins to decrease at 6mm from the edge of the tube module, the brightness of the edge area is slightly increased, and the dark frame is narrowed. The brightness of the solution of Example 2 begins to decrease at 3mm from the edge of the backlight module, and there is no bright band or dark frame.

[0204] When the first light-emitting device and the second light-emitting device use light-emitting devices with the same parameters, their maximum main light-emitting angles are the same (i.e., β = β') and their minimum main light-emitting angles are also the same (i.e., α = α'); if they use light-emitting devices with different parameters, their maximum main light-emitting angles may be different and their minimum main light-emitting angles may also be the same.

[0205] It should be understood that the above examples are only examples of the verification process of a part of the solutions disclosed in the present invention. The verification of other solutions not shown can be carried out in a similar manner, which will not be described in detail here.

[0206] Based on the same inventive concept, an embodiment of the present disclosure provides a display device, comprising:

[0207] The backlight module as described above is a direct-lit backlight module.

[0208] The display panel is located on the light-emitting surface of the backlight module.

[0209] The display device may be a liquid crystal display, a liquid crystal display screen, a liquid crystal television or other display device, or may be a mobile device such as a mobile phone, a tablet computer, or a notebook.

[0210] Although the preferred embodiments of the present disclosure have been described, those skilled in the art may make additional changes and modifications to these embodiments once they have learned the basic creative concepts. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments and all changes and modifications that fall within the scope of the present disclosure.

[0211] Obviously, those skilled in the art may make various changes and modifications to the present disclosure without departing from the spirit and scope of the present disclosure. Thus, if these modifications and variations of the present disclosure fall within the scope of the claims of the present disclosure and their equivalents, the present disclosure is intended to include these modifications and variations.

Claims

1. A backlight module, comprising: A back plate and a diffuser plate arranged opposite to each other, and a middle frame arranged along an edge area of ​​the back plate, wherein the middle frame abuts against the diffuser plate; A plurality of light-emitting devices are located on a side of the back plate facing the diffuser plate; the light-emitting device located on the outermost side of the plurality of light-emitting devices is a first light-emitting device, and the light-emitting device closest to the first light-emitting device in a first direction in which the middle frame points to the first light-emitting device is a second light-emitting device; The distance between the first light-emitting device and the inner wall of the middle frame, and the distance between the first light-emitting device and the second light-emitting device satisfy: a first main light beam emitted by the first light-emitting device to the middle frame is reflected by the middle frame and projected so that the first light-emitting device and the second light-emitting device are directly projected between the projection positions of the diffuser plate, and a second main light beam emitted by the second light-emitting device to the middle frame passes through the abutment position between the middle frame and the diffuser plate.

2. In the backlight module as described in claim 1, the distance between the second light-emitting device and the inner wall of the middle frame satisfies: at least the main light emitted by the second light-emitting device at a minimum main light-emitting angle to the first light-emitting device side passes through the abutment position; or, at least the main light emitted by the second light-emitting device at a maximum main light-emitting angle to the first device side passes through the abutment position.

3. The backlight module according to claim 1 or 2, wherein the distance between the second light emitting device and the inner wall of the middle frame is in the range of OD / tanc2 to OD / tanb2; in, OD is the distance between the back plate and the diffuser, b2 is the complementary angle of the maximum main light emitting angle of the second light emitting device, and c2 is the complementary angle of the minimum main light emitting angle of the second light emitting device.

4. The backlight module according to claim 3, wherein the distance between the first light emitting device and the inner wall of the middle frame is in the range of 1 / 3 OD / tan c1≤L1≤1 / 3 OD / tan b1; L1 is the distance between the first light emitting device and the inner wall of the middle frame; wherein, b1 is the complementary angle of the maximum main light-emitting angle of the first light-emitting device, and c1 is the complementary angle of the minimum main light-emitting angle of the first light-emitting device; The distance between the first light emitting device and the second light emitting device has a value range of: 2 / 3 OD / tan c2≤L2≤2 / 3 OD / tan b2; L2 is the distance between the first light emitting device and the second light emitting device.

5. The backlight module according to any one of claims 2 to 4, wherein the distance between the first light-emitting device and the second light-emitting device is twice the distance between the first light-emitting device and the inner wall of the middle frame.

6. The backlight module according to any one of claims 1 to 5, wherein the middle frame has an inclined portion and a vertical portion, the vertical portion is located between the inclined portion and the back plate and contacts the back plate; the inclined portion has a first reflective slope facing the side where the first light emitting device is located and abuts against the diffuser; The inclination angle of the first reflecting bevel satisfies: the second main light beam is at least partially projected onto the first reflecting bevel, and the second main light beam is perpendicular to the diffuser after being reflected by the first reflecting bevel; or the edge of the second main light beam passes through the abutment position between the first reflecting bevel and the diffuser.

7. The backlight module according to claim 6, wherein the range of the tilt angle is: (90°-c2) / 2≤δ≤(90°-b2) / 2; in, δ is the tilt angle, c2 is the complementary angle of the minimum main light-emitting angle of the second light-emitting device, and b2 is the complementary angle of the maximum main light-emitting angle of the second light-emitting device. 8 . The backlight module according to claim 6 , wherein a position where the middle frame abuts against the diffusion plate comprises a support surface, and the support surface is parallel to the diffusion plate.

9. As described in any one of claims 7-8, the length of the first reflecting slope in the first direction of the orthographic projection of the light guide plate satisfies: the third main light beam emitted by the first light-emitting device to the middle frame side is projected on the vertical part, so that the third main light beam is reflected by the vertical part and then projected onto the area on the diffuser corresponding to the area between the first light-emitting device and the second light-emitting device.

10. The backlight module according to claim 8, wherein the length of the first reflective inclined surface in the first direction is: L4 = (OD-L1×tanc1)×tanδ; in, L4 is the length of the first reflective slope in the first direction, OD is the distance between the back plate and the diffuser, L1 is the distance between the first light-emitting device and the middle frame, c1 is the complementary angle of the minimum main light-emitting angle of the first light-emitting device, and δ is the inclination of the first reflective slope. horn.

11. The backlight module according to any one of claims 6 to 10, wherein the middle frame comprises: A first body, located at the inclined portion, the first body having a first surface, a second surface, and a connecting structure connected in sequence to the inclined surface, the first surface intersects the diffuser plate, the second surface is parallel to the diffuser plate and has no contact with the diffuser plate, the inclined surface is located at a side of the first surface close to the first light-emitting device, and one end of the inclined surface abuts against the diffuser plate; The connecting structure extends from the second surface to the back plate side and is perpendicular to the second surface; The first reflective structure is located on a side of the first body close to the first light emitting device, wherein a portion of the first reflective structure is located on the inclined portion, and another portion of the first reflective structure is located on the vertical portion.

12. The backlight module according to claim 11, wherein one end of the connection structure away from the diffusion plate is not in contact with a surface of the back plate facing the diffusion plate, and the connection structure has a mounting hole in the first direction; The back plate comprises: A second body, parallel to the diffusion plate; The frame extends along the edge of the second body toward the diffusion plate to reach the side of the connecting structure away from the first light-emitting device; the frame has a through hole penetrating the frame at a position corresponding to the mounting hole, and a connecting member passes through the through hole and is fixedly connected to the mounting hole to connect the frame and the connecting structure. 13 . The backlight module according to claim 12 , wherein in the second direction from the diffusion plate to the back plate, the frame has bending portions at both ends of the through hole, and a thread is disposed in the through hole.

14. The backlight module according to claim 11, wherein the connecting structure extends from the second surface to a surface of the back plate facing the diffusion plate and is perpendicular to the second surface; One end of the connection structure away from the diffusion plate abuts against the back plate, and a surface of the connection structure away from the first reflection structure is flush with the first surface and the end surface of the diffusion plate.

15. The backlight module according to claim 14, wherein the longitudinal section of the connection structure is L-shaped; One end of the first part of the L-shape perpendicular to the diffuser plate away from the second part parallel to the diffuser plate is connected to the second surface, and the second part is located on the back plate close to the diffuser plate. one side surface.

16. The backlight module according to claim 15, wherein the back plate comprises a first area and a second area surrounding the first area, and the distance between the portion of the back plate located in the first area and the diffuser plate is smaller than the distance between the portion of the back plate located in the second area and the diffuser plate; The second portion is located in the second area, and a height of the second portion is a height difference between a portion of the back plate in the first area and a portion of the back plate in the second area. 17 . The backlight module according to claim 16 , wherein the second portion further comprises a protrusion, and the protrusion is located on a side surface of the second portion close to the diffusion plate.

18. The backlight module according to any one of claims 11 to 17, wherein the first body further comprises: The vertical structure is located on a side of the connecting structure close to the light emitting device, and a side of the vertical structure close to the light emitting device is connected to the inclined surface, and a side of the vertical structure close to the diffusion plate is connected to the second surface.

19. The backlight module as described in claim 18, wherein the vertical structure further comprises an extension portion, wherein the extension portion extends along an end away from the diffuser plate toward the side where the first light-emitting device is located, and the extension portion is parallel to the diffuser plate and contacts a surface of the back plate close to the diffuser plate.

20. The backlight module according to claim 18 or 19, wherein the first body further comprises: A transition structure is connected between the vertical structure and the second surface, wherein a surface of the transition structure facing the first light emitting device is connected between the inclined surface and a surface of the vertical structure, and a surface of the vertical structure faces the first light emitting device.

21. The backlight module according to any one of claims 11 to 20, further comprising a reflective sheet, wherein the reflective sheet is located on a side of the back plate facing the diffuser plate.

22. The backlight module according to claim 21, wherein the first body is integrally formed by injection molding, and the first reflective structure is a reflective film; The first body is made of metal. The reflective sheet located on the surface of the back plate facing the diffuser extends along the surface of the first body facing the first light-emitting device to the diffuser to form the first reflective structure.

23. The backlight module according to any one of claims 1 to 22, further comprising: A second reflective structure is fixed to a side of the back plate facing the diffuser plate and is located between the first light emitting device and the second light emitting device; The second reflecting structure has a second reflecting bevel, and the second reflecting bevel is used to reflect a third main light beam formed by the main light emitted by the first light-emitting device to the side where the second light-emitting device is located, so that the third main light beam is irradiated on the surrounding area where the middle frame and the diffuser plate are abutted, and the second reflecting structure does not block the second main light beam.

24. The backlight module according to claim 23, wherein the second reflective structure further comprises: a vertical surface, the vertical surface facing the second light emitting device and intersecting the second reflective inclined surface; The bottom surface is located on a side of the back plate facing the diffuser plate, and connects the vertical surface and the second reflective inclined surface.

25. The backlight module according to claim 24, wherein the height of the vertical surface satisfies: the main light emitted by the first light emitting device at the minimum main light emitting angle toward the second reflective inclined surface reaches the diffuser after being reflected by the second reflective inclined surface, and the vertical surface does not block the main light emitted by the second light emitting device at the maximum main light emitting angle toward the first light emitting device side; The angle between the second reflective bevel and the vertical plane satisfies: a main light ray emitted from the first light emitting device toward the second reflective bevel at a maximum main light emitting angle intersects the second reflective bevel and reaches the middle frame after being reflected by the second reflective bevel.

26. The backlight module according to claim 25, wherein the angle satisfies the following constraints: tan(180°+b1-2γ)≥(L5-H1) / (L3-L5); tan(180°+c1-2γ)≤(OD-H) / (L1+L3); in, L5=L3(tanc1-tanb1) / (tanγ-tanb1); H1=L3×tanc-L3×tanγ(tanc1-tanb1) / (tanγ-tanb1); γ is the angle, b1 is the complementary angle of the maximum main light-emitting angle of the first light-emitting device, c1 is the complementary angle of the minimum main light-emitting angle of the first light-emitting device, L1 is the distance between the first light-emitting device and the middle frame, L2 is the distance between the first light-emitting device and the second light-emitting device, L3 is the distance between the first light-emitting device and the vertical plane, the vertical plane is parallel to the center line of the first light-emitting device, H is the height of the vertical plane, and OD is the spacing between the back panel and the diffuser.

27. The backlight module according to claim 25, wherein the height of the vertical surface satisfies the following constraint relationship: H = (L2-L3) x tanb1 = L3 x tanc1; in, The H is the height of the vertical surface.

28. The backlight module according to any one of claims 24 to 27, wherein the second reflective structure further comprises: A plurality of fixing structures, one end of each fixing structure is connected to the bottom surface of the second reflecting structure, and the other end of each fixing structure has a hook extending in the direction of the second reflecting structure.

29. The backlight module according to claim 28, wherein the second reflective structure and the plurality of fixing structures are integrally formed by injection molding.

30. A display device comprising: The backlight module according to any one of claims 1 to 29; The display panel is located on the light emitting surface of the backlight module.

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