Backlight module and display device

Abstract

A backlight module and a display device, the backlight module comprising: oppositely arranged back plate (1) and diffusion plate (2), and middle frame (3) arranged along the edge of back plate (1) and abutting with diffusion plate (2); a plurality of light emitting devices (4) are located on the side of back plate (1) facing diffusion plate (2); the light emitting device (4) located at the outermost side in the plurality of light emitting devices (4) is the first light emitting device (4a), in the first direction of middle frame (3) pointing to the first light emitting device (4a), the light emitting device (4) closest to the first light emitting device (4a) is the second light emitting device (4b); the distance between the first light emitting device (4a) and the inner side wall of middle frame (3), and the distance between the first light emitting device (4a) and the second light emitting device (4b) satisfy: the first main light beam (4a1) emitted by the first light emitting device (4a) to middle frame (3) is projected between the projection positions of the first light emitting device (4a) and the second light emitting device (4b) on diffusion plate (2) after being reflected by middle frame (3), and the second main light beam (4b1) emitted by the second light emitting device (4b) to middle frame (3) passes through the abutting position of middle frame (3) and diffusion plate (2).

Description

Technical Field

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

[0002] Because the brightness around the display screen typically decreases to varying degrees, a dark band of a certain width will appear near the seam of the video wall in the video wall product (e.g., Figure 1 (As shown), this will significantly affect the visual effect.

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

[0004] This disclosure provides a backlight module and a display device to solve the aforementioned technical problems in the prior art.

[0005] In a first aspect, to solve the above-mentioned technical problems, embodiments of this disclosure provide a backlight module, including:

[0006] A back plate and a diffuser plate are arranged opposite to each other, and a middle frame is arranged along the edge region of the back plate, the middle frame abutting against the diffuser plate;

[0007] Multiple light-emitting devices are located on the side of the back plate facing the diffuser plate; among the multiple light-emitting devices, the outermost light-emitting device is the first light-emitting device, and the light-emitting device closest to the first light-emitting device in the first direction of the middle frame pointing towards the first light-emitting device is the second light-emitting device;

[0008] The distance between the first light-emitting device and the inner sidewall of the middle frame, and the distance between the first light-emitting device and the second light-emitting device, satisfy the following conditions: the first main light beam emitted by the first light-emitting device toward the middle frame is reflected by the middle frame and projected onto the projection position of the first light-emitting device and the second light-emitting device, and the second main light beam emitted by the second light-emitting device toward the middle frame passes through the contact position between the middle frame and the diffuser plate.

[0009] In one possible implementation, the distance between the second light-emitting device and the inner sidewall of the middle frame satisfies the following conditions: at least the main light emitted by the second light-emitting device towards the first light-emitting device at the minimum main emission angle passes through the contact position; or at least the main light emitted by the second light-emitting device towards the first light-emitting device at the maximum main emission angle passes through the contact position.

[0010] In one possible implementation, the distance between the second light-emitting device and the inner sidewall of the middle frame ranges from OD / tanc2 to OD / tanb2;

[0011] Wherein, OD is the distance between the back plate and the diffuser plate, b2 is the complementary angle of the maximum main emission angle of the second light-emitting device, and c2 is the complementary angle of the minimum main emission angle of the second light-emitting device.

[0012] In one possible implementation, the distance between the first light-emitting device and the inner sidewall 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 sidewall of the middle frame; where b1 is the complementary angle of the maximum principal light-emitting angle of the first light-emitting device, and c1 is the complementary angle of the minimum principal light-emitting angle of the first light-emitting device.

[0013] The distance between the first light-emitting device and the second light-emitting device is in the 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.

[0014] In one possible implementation, 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 sidewall of the middle frame.

[0015] In one possible implementation, the middle frame has an inclined portion and a vertical portion, the vertical portion being located between the inclined portion and the back plate and in contact with 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;

[0016] The tilt angle of the first reflecting slope satisfies the following conditions: the second main beam is at least partially projected onto the first reflecting slope, and the second main beam is perpendicular to the diffuser after being reflected by the first reflecting slope; or, the edge of the second main beam passes through the contact position between the first reflecting slope and the diffuser.

[0017] One possible implementation is that the range of the tilt angle is:

[0018] (90°-c2) / 2≤δ≤(90°-b2) / 2;

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

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

[0021] In one possible implementation, the length of the orthographic projection of the first reflective slope onto the diffuser plate in the first direction satisfies the following: a third main beam emitted by the first light-emitting device toward the middle frame side is projected onto the vertical portion, such that the third main beam is reflected by the vertical portion and then projected onto the diffuser plate in the area corresponding to the region between the first light-emitting device and the second light-emitting device.

[0022] In one possible implementation, the length of the first reflective slope in the first direction is:

[0023] L4=(OD-L1×tanc1)×tanδ;

[0024] Wherein, L4 is the length of the first reflective slope in the first direction, OD is the distance between the back plate and the diffuser plate, L1 is the distance between the first light-emitting device and the middle frame, c1 is the complementary angle of the minimum main emission angle of the first light-emitting device, and δ is the tilt angle of the first reflective slope.

[0025] One possible implementation includes the middle frame comprising:

[0026] A first body is located in the inclined portion. The first body has a first surface, a second surface, and a connecting structure connected to the inclined surface in sequence. The first surface intersects the diffuser plate, the second surface is parallel to the diffuser plate and does not contact it, the inclined surface is located on the side of the first surface near 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.

[0027] The first reflective structure is located on the side of the first body close to the first light-emitting device. A portion of the first reflective structure is located in the inclined portion, and another portion is located in the vertical portion.

[0028] In one possible implementation, the end of the connecting structure away from the diffuser plate does not contact the side of the back plate facing the diffuser plate, and the connecting structure has mounting holes in the first direction;

[0029] The backplate includes:

[0030] The second body is parallel to the diffuser plate;

[0031] The frame extends along the edge of the second body toward the diffuser plate to the side of the connecting structure away from the first light-emitting device; the frame has a through hole at the position corresponding to the mounting hole, and the connector passes through the through hole and is fixedly connected to the frame and the connecting structure with the mounting hole.

[0032] In one possible implementation, in a second direction where the diffuser plate points toward the back plate, the frame has bent portions at both ends of the through hole, and the through hole is provided with threads.

[0033] In one possible implementation, the connection structure extends from the second surface to the side of the back plate facing the diffuser plate and is perpendicular to the second surface;

[0034] The end of the connecting structure away from the diffuser plate abuts against the back plate, and the side of the connecting structure away from the first reflective structure is flush with the first surface and the end face of the diffuser plate.

[0035] In one possible implementation, the longitudinal cross-sectional shape of the connection structure is L-shaped;

[0036] The first part of the L-shape perpendicular to the diffuser plate is connected to the second surface at one end away from the second part parallel to the diffuser plate, and the second part is located on the side surface of the back plate close to the diffuser plate.

[0037] In one possible implementation, the backplate includes a first region and a second region surrounding the first region, wherein the distance between the portion of the backplate located within the first region and the diffuser plate is less than the distance between the portion of the backplate located within the second region and the diffuser plate.

[0038] The second part is located in the second region, and the height of the second part is the height difference between the portion of the back plate in the first region and the portion in the second region.

[0039] In one possible implementation, the second portion further includes a protrusion located on the side surface of the second portion near the diffuser plate.

[0040] In one possible implementation, the first body further includes:

[0041] A vertical structure is located on the side of the connecting structure closer to the light-emitting device, and the side of the vertical structure closer to the light-emitting device is connected to the inclined surface, and the side of the vertical structure closer to the diffuser plate is connected to the second surface.

[0042] In one possible implementation, the vertical structure further has an extension that extends from one end away from the diffuser towards the side where the first light-emitting device is located, and the extension is parallel to the diffuser and contacts the side of the back plate near the diffuser.

[0043] In one possible implementation, the first body further includes:

[0044] A transition structure is provided between the vertical structure and the second surface. The side of the transition structure facing the first light-emitting device is connected between the inclined surface and one side of the vertical structure, and one side of the vertical structure faces the side where the first light-emitting device is located.

[0045] In one possible implementation, the backlight module further includes a reflective sheet located on the side of the backplate facing the diffuser plate.

[0046] In one possible implementation, the first body is integrally molded using an injection molding process, and the first reflective structure is a reflective film;

[0047] The first body is made of metal, and the reflective sheet located on the back plate facing the diffuser plate extends along the surface of the first body facing the first light-emitting device to the diffuser plate to form the first reflective structure.

[0048] In one possible implementation, the backlight module further includes:

[0049] The second reflective structure is fixed to the 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 the third main beam formed by the main light emitted by the first light-emitting device towards the side where the second light-emitting device is located, so that the third main beam illuminates the surrounding area where the middle frame abuts the diffuser plate, and the second reflective structure does not block the second main beam.

[0050] In one possible implementation, the second reflective structure further includes:

[0051] A vertical surface, which faces the second light-emitting device and intersects with the second reflective inclined surface;

[0052] The bottom surface, located on the side of the back plate facing the diffuser plate, connects the vertical surface and the second reflective slope.

[0053] In one possible implementation, the height of the vertical surface satisfies the following conditions: the main light emitted by the first light-emitting device at the minimum main emission angle toward the second reflective inclined surface reaches the diffuser plate 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 emission angle toward the side of the first light-emitting device;

[0054] The angle between the second reflective slope and the vertical plane satisfies the following condition: the main light rays emitted by the first light-emitting device at the maximum main emission angle intersect with the second reflective slope and reach the middle frame after being reflected by the second reflective slope.

[0055] In one possible implementation, the included angle satisfies the following constraints:

[0056] tan(180°+b1-2γ)≥(L5-H1) / (L3-L5);

[0057] tan(180°+c1-2γ)≤(OD-H) / (L1+L3);

[0058] Where L5 = L3(tanc1 - tanb1) / (tanγ - tanb1);

[0059] H1=L3×tanc-L3×tanγ(tanc1-tanb1) / (tanγ-tanb1);

[0060] γ is the included angle, b1 is the complementary angle of the maximum principal emission angle of the first light-emitting device, c1 is the complementary angle of the minimum principal emission 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 plate and the diffuser plate.

[0061] In one possible implementation, the height of the vertical plane satisfies the following constraint:

[0062] H=(L2-L3)×tanb1=L3×tanc1;

[0063] Wherein, H is the height of the vertical plane.

[0064] In one possible implementation, the second reflective structure further includes:

[0065] Multiple fixed structures are provided, one end of which is connected to the bottom surface of the second reflective structure, and the other end has a hook extending in the direction of the second reflective structure.

[0066] In one possible implementation, the second reflective structure and the plurality of fixed structures are integrally molded using an injection molding process.

[0067] Secondly, embodiments of this disclosure provide a display device, including:

[0068] The backlight module as described in the first aspect;

[0069] The display panel is located on the light-emitting surface of the backlight module. Attached Figure Description

[0070] Figure 1 A schematic diagram of a dark frame added to the seam of a video wall in the related technology provided in the embodiments of this disclosure;

[0071] Figure 2 This is a schematic diagram of the structure of a backlight module provided in an embodiment of the present disclosure;

[0072] Figure 3 A brightness curve of a light-emitting device provided in an embodiment of this disclosure;

[0073] Figure 4 and Figure 5 A schematic diagram showing the main light rays from the edge of a second main beam illuminating the edge of a backlight module, provided in an embodiment of this disclosure;

[0074] Figures 6-8 This is a schematic diagram of the optical path of a first main beam provided in an embodiment of the present disclosure;

[0075] Figure 9 This is a schematic diagram of the structure of a backlight module provided in an embodiment of the present disclosure;

[0076] Figure 10 Provided for the embodiments of this disclosure Figure 9 A magnified view of the middle frame area corresponding to the center backlight module;

[0077] Figure 11 A constrained mathematical model for the tilt angle of a first reflecting slope provided in this embodiment of the present disclosure;

[0078] Figure 12 This is a schematic diagram of the structure of a backlight module provided in an embodiment of the present disclosure;

[0079] Figure 13 Provided for the embodiments of this disclosure Figure 12 A magnified view of the area containing the center frame;

[0080] Figure 14 This is a schematic diagram of another backlight module provided in an embodiment of the present disclosure;

[0081] Figure 15 This is a schematic diagram of the structure of a mid-frame provided in an embodiment of the present disclosure;

[0082] Figure 16 This is a schematic diagram of the structure of a backplate provided in an embodiment of the present disclosure;

[0083] Figure 17 This is a schematic diagram of a frame bending according to an embodiment of the present disclosure;

[0084] Figure 18 This is a schematic diagram of the structure of a middle frame and a back plate provided in an embodiment of the present disclosure;

[0085] Figures 19-20 This is a schematic diagram of another structure of the middle frame and back plate provided in an embodiment of this disclosure;

[0086] Figure 21 This is a schematic diagram of another structure of the middle frame and back plate provided in an embodiment of this disclosure;

[0087] Figure 22 This is a schematic diagram of another structure of the middle frame and back plate provided in an embodiment of this disclosure;

[0088] Figure 23 and Figure 24 This is a schematic diagram of the structure of a first body provided in an embodiment of the present disclosure;

[0089] Figure 25 This is a schematic diagram of another mid-frame structure provided in an embodiment of the present disclosure;

[0090] Figure 26 This is a schematic diagram of another backlight module provided in an embodiment of the present disclosure;

[0091] Figure 27 An optical path diagram of a third master beam provided in an embodiment of this disclosure;

[0092] Figure 28 This is a schematic diagram of a second reflective structure provided in an embodiment of the present disclosure;

[0093] Figure 29 A schematic diagram illustrating the change of the tilt angle of the first reflecting slope provided in an embodiment of this disclosure;

[0094] Figure 30 The figure shows the edge brightness curves before and after backlight module optimization.

[0095] Figure label:

[0096] 1. Back plate, 2. Diffuser plate, 3. Middle frame, 4. Light-emitting device, 4a. First light-emitting device, 4b. Second light-emitting device, 5. Second reflective structure, 51. Second reflective slope, 4a1. First main beam, 4b1. Third main beam, 4a2. Vertical surface, 52. Bottom surface, 53. Fixing structure, 54. First reflective slope, 3s. First body, 31. First reflective structure, 32. First surface, 311. Second surface, 312. Sloping surface, 313. Support surface, 3m. Connecting structure, 314. Second body, 11. Frame, 12. Mounting hole, K. Through hole, K'. Bending part, 121. Reflective sheet, 6. Vertical structure, 315. Transition structure, 316.

[0097] First direction X, second direction Y, minimum principal emission angle α of the first light-emitting device, maximum principal emission angle β of the first light-emitting device, included angle γ, minimum principal emission angle α' of the second light-emitting device, maximum principal emission angle β' of the second light-emitting device, and tilt angle δ of the first reflective slope. Detailed Implementation

[0098] This disclosure provides a backlight module and a display device to solve the aforementioned technical problems in the prior art.

[0099] To make the above-described objects, features, and advantages of this disclosure more apparent and understandable, the disclosure will be further described below in conjunction with the accompanying drawings and embodiments. However, the exemplary embodiments can be implemented in many forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided to make the disclosure more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art. The same reference numerals in the figures denote the same or similar structures, and therefore repeated descriptions of them will be omitted. Terms describing position and direction as described in this disclosure are illustrative of the accompanying drawings, but changes may be made as needed, and all such changes are included within the scope of protection of this disclosure. The accompanying drawings of this disclosure are for illustrative purposes only and do not represent actual scale.

[0100] It should be noted that specific details are set forth in the following description to provide a full understanding of this disclosure. However, this disclosure can be implemented in many ways other than those described herein, and those skilled in the art can make similar extensions without departing from the spirit of this disclosure. Therefore, this disclosure is not limited to the specific embodiments disclosed below. The following descriptions are preferred embodiments for carrying out this disclosure; however, these descriptions are for the purpose of illustrating the general principles of this disclosure and are not intended to limit the scope of this disclosure. The scope of protection of this disclosure shall be determined by the appended claims.

[0101] The following description, in conjunction with the accompanying drawings, details a backlight module and display device provided in the embodiments of this disclosure.

[0102] Please see Figure 2 This is a schematic diagram of a backlight module provided in an embodiment of the present disclosure. The backlight module includes:

[0103] 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, with the middle frame 3 abutting against the diffuser plate 2;

[0104] Multiple light-emitting devices 4 are located on the side of the back plate 1 facing the diffuser plate 2; among the multiple light-emitting devices 4, the outermost light-emitting device 4 is the first light-emitting device 4a, and the light-emitting device 4 closest to the first light-emitting device 4a in the first direction X of the middle frame 3 is the second light-emitting device 4b.

[0105] The distance L1 between the first light-emitting device 4a and the inner sidewall 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: the first main beam 4a1 emitted by the first light-emitting device 4a toward the middle frame 3 is reflected by the middle frame 3 and projected onto the projection position between the first light-emitting device 4a and the second light-emitting device 4b, and the second main beam 4b1 emitted by the second light-emitting device 4b toward the middle frame 3 passes through the contact position between the middle frame 3 and the diffuser plate 2.

[0106] Please see Figure 3 This is a brightness curve of a light-emitting device provided in an embodiment of the present disclosure. Figure 3 The horizontal axis represents the emission angle of the 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 usually called the maximum principal emission angle, and the minimum emission angle is called the minimum principal emission angle. Light rays emitted at emission angles between the minimum and maximum principal emission angles are called principal rays, and the beam composed of all the principal rays of a light-emitting device 4 is called the principal beam. Figure 3 Regarding the brightness curve of the light-emitting device 4 shown, the maximum brightness is 76, half of the maximum brightness is 38, the minimum principal emission angle corresponding to brightness of 38 is approximately 60°, and the maximum principal emission angle is approximately 80°. Figure 3 The two peaks shown correspond to the two sides of the light-emitting device 4, as follows: Figure 2 The first light-emitting device 4a shown is assumed to have a wave peak facing the middle frame 3. Figure 3 The wave peaks shown in the diagram, ranging from 10° to 90°, correspond to the wave peak on the side of the first light-emitting device 4a facing the second light-emitting device 4b. Figure 3 The wave peaks shown are -10° to -90°.

[0107] In this disclosure, in order to distinguish the main beams emitted by the first light-emitting device 4a and the second light-emitting device 4b, the main beam emitted by the first light-emitting device 4a toward the middle frame side is called the first main beam (denoted as 4a1), the main beam emitted by the first light-emitting device 4a toward the second light-emitting device 4b side is called the third main beam (denoted as 4a2), and the main beam emitted by the second light-emitting device 4b toward the first light-emitting device 4a (i.e., the middle frame 3) side is called the second main beam (denoted as 4b1). Figure 2 The main beam emitted by the light-emitting device 4 in the middle is similar to a radial trumpet shape.

[0108] like Figure 2As shown, by adjusting the distance L1 between the first light-emitting device 4a and the inner wall of the middle frame 3, the first main beam 4a1 emitted by the first light-emitting device 4a towards the middle frame 3 is reflected by the inner wall 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 projected onto the diffuser plate 3. This prevents the first main beam 4a1 from entering the area between the projection position of the first light-emitting device 4a and the contact position between the middle frame 3 and the diffuser plate 2, thus preventing it from illuminating the same area as other main beams and causing a bright band in the corresponding area. At the same time, it also prevents the first main beam 4a1 from entering the area on the side of the projection position of the second light-emitting device 4b that is far from the middle frame 3, thus causing a dark band between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b.

[0109] By adjusting the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b, the second main beam 4b1 emitted by the second light-emitting device 4b towards the middle frame 3 passes through the position where the diffuser plate 2 and the middle frame 3 abut, which can improve the brightness near the position where the diffuser plate 2 and the middle frame 3 abut (i.e., the edge of the backlight module).

[0110] Therefore, in the embodiments provided in this disclosure, by adjusting the distance L1 between the first light-emitting device 4a and the inner sidewall 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 beam 4b1 passes through the contact position between the middle frame 3 and the diffuser plate 2, so that the second main beam 4b1 emitted by the second light-emitting device 4b towards the first light-emitting device 4a (which is also the middle frame 3) can illuminate the edge of the backlight module, thereby improving the brightness of the backlight module edge; and also so that the first main beam 4a1 emitted by the first main beam 4a1 towards the middle frame 3 can be reflected by the inner sidewall 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 projected onto the diffuser plate 3, thereby preventing bright and dark bands from appearing 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.

[0111] Please see Figure 4 and Figure 5 A schematic diagram of the main light rays from the edge of the second main beam illuminating the edge of the backlight module, provided in an embodiment of this disclosure. The distance (L1+L2) between the second light-emitting device 4b and the inner sidewall 3a of the middle frame 3 satisfies: Figure 4 As shown, at least the main light emitted by the second light-emitting device 4b towards the first light-emitting device 4a at the minimum main emission angle α' passes through the contact position. This allows the edge of the second main beam 4b1 to pass through the edge of the backlight module while the second main beam 4b2 illuminates the vicinity of the middle frame 3 near the contact position. This allows the inner wall 3a of the middle frame 3 to reflect the second main beam 4b1 to the edge of the diffuser plate 2, increasing the brightness of the backlight module edge; or, as... Figure 5As shown, at least the main light emitted by the second light-emitting device 4b towards the first light-emitting device 4a at the maximum main emission angle β' passes through the contact position, so that the second main beam 4b1 can directly irradiate the edge of the diffuser plate 2 until the contact position with the middle frame 3, thereby improving the brightness of the backlight module edge.

[0112] In the embodiments provided in this disclosure, by controlling the distance (L1+L2) between the second light-emitting device 4b and the inner sidewall 3a of the middle frame 3, at least the light emitted by the second light-emitting device 4b towards the first light-emitting device 4a at the minimum principal emission angle α' passes through the contact position, or the light emitted by the second light-emitting device 4b towards the first light-emitting device 4a at the maximum principal emission angle β' passes through the contact position. This ensures that at least the principal light rays at the edge of the second principal beam 4b1 pass through the contact position between the middle frame 3 and the diffuser plate 2, thereby effectively improving the brightness of the backlight module edge and improving the dark frame.

[0113] Please continue reading Figure 4 and Figure 5 The distance (L1+L2) between the second light-emitting device 4b and the inner sidewall 3a of the middle frame 3 ranges from OD / tanc2 to OD / tanb2.

[0114] Wherein, OD is the distance between the back plate 1 and the diffuser plate 2, b2 is the complementary angle of the maximum principal emission angle β' of the second light-emitting device 4b (i.e., b2 = 90° - β'), and c2 is the complementary angle of the minimum principal emission angle α' of the second light-emitting device 4b (i.e., c2 = 90° - α').

[0115] In the embodiments provided in this disclosure, by setting the range of the distance (L1+L2) between the second light-emitting device 4b and the inner sidewall 3a of the middle frame 3 to OD / tanc2~OD / tanb2, it can be ensured that the second main beam 4b1 emitted by the second light-emitting device 4b towards the middle frame 3 passes through the contact 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.

[0116] 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 / 3OD / tan c1≤L1≤1 / 3OD / tan b1; L1 is the distance between the first light-emitting device and the inner sidewall of the middle frame; where b1 is the complementary angle of the maximum principal light-emitting angle β of the first light-emitting device (i.e., b1=90°-β), and c1 is the complementary angle of the minimum principal light-emitting angle α of the first light-emitting device (i.e., c1=90°-α).

[0117] The range of the distance L2 between the first light-emitting device 4a and the second light-emitting device 4b is: 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.

[0118] The first light-emitting device 4a and the second light-emitting device 4b can be light-emitting devices with the same main emission angle, in which case α=α' (corresponding c1=c2) and 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 emission angles, in which case α≠α' (corresponding c1≠c2) and β≠β' (corresponding b1≠b2).

[0119] In the embodiments provided in this disclosure, by setting the range of the distance L1 between the first light-emitting device 4a and the inner sidewall 3a of the middle frame 3 to 1 / 3 OD / tan c1≤L1≤1 / 3 OD / tan b1; where b1 is the complementary angle of the maximum principal emission angle β of the first light-emitting device, and c1 is the complementary angle of the minimum principal emission angle α of the first light-emitting device; and setting the 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 beam 4a1 can be reflected by the inner sidewall 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, and the main light rays in the second main beam 4b1 can pass through the contact position between the diffuser plate 2 and the middle frame 3.

[0120] Please see Figures 6-8 This is a schematic diagram of the optical path of a first main beam provided in an embodiment of the present disclosure.

[0121] like Figure 6 As shown, if L2>2L1, then after the first main beam 4a1 is reflected by the inner wall 3a of the middle frame 3, at least part of the first main 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 region between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b.

[0122] like Figure 7 As shown, if L2 < 2L1, then after the first main beam 4a1 is reflected by the inner sidewall 3a of the middle frame 3, at least part of the first main 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.

[0123] like Figure 8As shown, 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 wall 3b of the middle frame 3, i.e., L2 = 2L1. At this time, the first main beam 4a1 emitted by the first light-emitting device 4a towards the middle frame 3 is reflected by the inner wall 3a of the middle frame 3 to the area of ​​the projection positions of the first light-emitting device 4a and the second light-emitting device 4b in the diffuser plate 2, thereby ensuring that there is no dark area between the projection positions of the first light-emitting device 4a and the second light-emitting device 4b, and that there is no bright area between the first light-emitting device 4a and the middle frame 3.

[0124] Therefore, in the embodiments provided in this 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 sidewall of the middle frame 3, it is possible not only to ensure that there is no dark area between the first light-emitting device 4a and the second light-emitting device 4b, but also to make the brightness of the edge area of ​​the backlight module uniform.

[0125] Please see Figure 9 and Figure 10 , Figure 9 This is a schematic diagram of the structure of a backlight module provided in an embodiment of the present disclosure. Figure 10 Provided for the embodiments of this disclosure Figure 9 The image shows a magnified view of the central backlight module corresponding to the mid-frame area. (Example:) Figure 9 As shown, the middle frame 3 has an inclined portion and a vertical portion. The vertical portion is located between the inclined portion and the back plate 1 and is in contact with the back plate 1. The inclined portion has a first reflective inclined surface 3s facing the side where the first light-emitting device 4a is located and abuts against the diffuser plate 2. The first reflective inclined surface 3s is a part of the inner sidewall 3a of the middle frame 3 located in the inclined portion.

[0126] like Figure 10 As shown, the tilt angle δ of the first reflecting slope 3s satisfies the following conditions: the second main beam 4b1 is at least partially projected onto the first reflecting slope 3s, and the second main beam 4b1 is perpendicular to the diffuser plate 2 after being reflected by the first reflecting slope 3s; or, the edge of the second main beam 4b1 passes through the contact position between the first reflecting slope 3s and the diffuser plate 2.

[0127] In the embodiments provided in this disclosure, by having the second main beam 4b1 emitted by the second light-emitting device 4b toward the middle frame 3 side project at least partially onto the first reflective slope 3s, and the second main beam 4b1 being perpendicular to the diffuser plate 2 after being reflected by the first reflective slope 3s; or by having the edge of the second main beam 4b1 pass through the contact position between the first reflective slope 3s and the diffuser plate 2, the second main beam 4b1 can be made to illuminate the edge area of ​​the diffuser plate 2, thereby improving the brightness of the edge area of ​​the backlight module.

[0128] Please see Figure 11A constrained mathematical model for the tilt angle of a first reflecting slope 3s provided in this embodiment of the present disclosure.

[0129] Figure 11 Assume that the exit angle of a main ray emitted by the second light-emitting device 4b towards the middle frame 3 is (90°-e), where e is the complementary angle of the exit angle of this main ray. When this main ray reaches the first reflecting slope 3s, it is reflected by the first reflecting slope 3s to the diffuser plate 2 and enters the diffuser plate 2 at an angle perpendicular to the diffuser plate 2. Therefore, the tilt angle of the first reflecting slope 3s can be determined as δ=(90°-e) / 2, and α'≤(90°-e)≤β', therefore α' / 2≤δ≤β' / 2.

[0130] The range of the tilt angle of the first reflecting slope 3s can also be expressed as:

[0131] (90°-c2) / 2≤δ≤(90°-b2) / 2;

[0132] Wherein, δ is the tilt angle of the first reflecting slope 3s, c2 is the complementary angle of the minimum principal emission angle α' of the second light-emitting device 4b (i.e., c2=90°-α'), and b2 is the complementary angle of the maximum principal emission angle β' of the second light-emitting device 4b (i.e., b2=90°-β').

[0133] In the embodiments provided in this disclosure, by setting the tilt angle of the first reflective slope 3s of the middle frame 3 within (90°-c2) / 2≤δ≤(90°-b2) / 2, the second main beam 4b1 can be at least partially projected onto the first reflective slope 3s, and the second main beam 4b2 is perpendicular to the diffuser plate 2 after being reflected by the first reflective slope 3s; or, the edge of the second main beam 4b2 passes through the contact position between the first reflective slope 3s and the diffuser plate 2.

[0134] Please see Figure 12 and Figure 13 , Figure 12 This is a schematic diagram of the structure of a backlight module provided in an embodiment of the present disclosure. Figure 13 Provided for the embodiments of this disclosure Figure 12 A magnified view of the area containing the central frame.

[0135] The middle frame 3 has a support surface 3m at the position where it abuts the diffuser plate 2, and the support surface 3m is parallel to the diffuser plate 2.

[0136] The length of the support surface 3m in the first direction X is d, where 1mm≤d≤1.5mm.

[0137] In the implementation provided in this disclosure, by setting a support surface 3m at the position where the middle frame 3 abuts against the diffuser plate 2, it is possible to easily assemble the middle frame 3 and the diffuser plate 2, thereby improving production efficiency.

[0138] Please see Figure 14 This is a schematic diagram of another backlight module provided in an embodiment of the present disclosure.

[0139] The length L4 of the orthographic projection of the first reflecting slope 3s onto the diffuser plate 2 in the first direction X satisfies the following: the first main beam 4a1 emitted by the first light-emitting device 4a toward the middle frame 3 is projected onto the vertical part of the middle frame 3, so that the first main beam 4a1 is reflected by the vertical part 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.

[0140] In the embodiments provided in this disclosure, by controlling the length L4 of the orthogonal projection of the first reflective inclined surface 3s onto the diffuser plate 2 in the first direction X, the following conditions are met: the first main beam 4a1 emitted by the first light-emitting device 4a toward the middle frame 3 is projected onto the vertical portion of the middle frame 3, so that the first main beam 4a1 is reflected by the vertical portion and projected onto the area in 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 dark areas from appearing 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 bright areas from appearing 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.

[0141] Please continue reading Figure 14 The length of the first reflecting slope 3s in the first direction X is:

[0142] L4=(OD-L1×tanc1)×tanδ;

[0143] Where L4 is the length of the first reflective inclined plane 3s in the first direction X, OD is the distance between the back plate 1 and the diffuser plate 2, L1 is the distance between the first light-emitting device 4a and the inner sidewall 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 tilt angle of the first reflective inclined plane 3s.

[0144] Please see Figure 15 This is a schematic diagram of the structure of a middle frame provided in an embodiment of this disclosure.

[0145] The middle frame 3 includes:

[0146] The first body 31 is located in the inclined portion. The first body 31 has a first surface 311, a second surface 312, an inclined surface 313, and a connecting structure 314 connected in sequence. The first surface 311 intersects with the diffuser plate 2, the second surface 312 is parallel to the diffuser plate 2 and does not contact it, the inclined surface 313 is located on the side of the first surface 311 near the first light-emitting device 4a, and one end of the inclined surface 313 abuts against 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.

[0147] The first reflective structure 32 is located on the side of the first body 31 closest to the first light-emitting device 4a. Part of the second reflective structure 32 is located in the inclined portion, and the other part is located in the vertical portion. The side of the first reflective structure 32 closest to the first light-emitting device 4a is the inner sidewall 3a of the middle frame 3.

[0148] The first face 311 can be perpendicular to the second face 312, or it can be at an obtuse angle to the second face 312.

[0149] Please continue reading Figure 14 and Figure 15 The end of the connecting structure 314 away from the diffuser plate 2 does not contact the side of the back plate 1 facing the diffuser plate 2, and the connecting structure 314 has a mounting hole K in the first direction X.

[0150] Please see Figure 16 This is a schematic diagram of the structure of a backplate provided in an embodiment of the present disclosure. The backplate 1 includes:

[0151] The second body 11 is parallel to the diffuser plate 2;

[0152] The frame 12 extends along the edge of the second body 11 toward the diffuser plate 2 and reaches the side of the connecting structure 314 away from the first light-emitting device 4a; the frame 12 has a through hole K' at the position corresponding to the mounting hole K, and the connector passes through the through hole K' and is fixedly connected to the frame 12 and the connecting structure 314 with the mounting hole K.

[0153] In this scheme, the first reflective structure 32 can be a metal reflective structure, such as a reflector. The metal reflective structure is attached to the surface of the first body 31 facing the first light-emitting device 4a, and extends towards the second body 11 until it contacts the second body 11.

[0154] In the embodiments provided in this disclosure, by providing a connecting structure 314 on the first body 31 of the middle frame 3, the body of the middle frame 3 and the second body 11 of the back plate 1 are not in contact. The size of the first body 31 can be made smaller. The frame 12 is set as the second body 11 and the frame 12 extending along the edge of the second body 11 towards the diffuser plate 2. The connecting structure 314 is provided with mounting holes K that connect to the frame 12 of the back plate 1. Correspondingly, the frame 12 of the back plate 1 is provided with through holes K' corresponding to the mounting holes K. Thus, the first body 31 of the middle frame 3 and the frame 12 of the back plate 1 can be fixed together with the connector. This can effectively reduce the manufacturing difficulty of the first body 31 and can also use the frame 12 of the back plate 1 to support the first body 31 of the middle frame 3, thereby improving the support strength between the back plate 1 and the diffuser plate 2.

[0155] Please see Figure 17 This is a schematic diagram of a frame bending according to an embodiment of the present disclosure.

[0156] 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 the through hole K' is provided with threads.

[0157] In the embodiments provided in this disclosure, by providing bending portions 121 at both ends of the through hole K', the depth of the through hole K' can be increased, and thus threads can be provided on the inner wall of the through hole K'. This not only allows the connecting parts between the frame 12 and the middle frame 3 to use threads without the need for nuts, thus facilitating assembly and improving production efficiency, but also reduces the depth of the middle frame 3 intruding into the display area of ​​the backlight module.

[0158] Please see Figure 18 This is a schematic diagram of the structure of a middle frame and a back plate provided in 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;

[0159] One end of the connecting structure 314 away from the diffuser plate 2 abuts against the back plate 1, and the side of the connecting structure 314 away from the first reflective structure 32 is flush with the end face of the first surface 311 and the diffuser plate 2.

[0160] like Figure 18 As shown, 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 plate 2 and the back plate 1, the connecting structure 314 is perpendicular to both the diffuser plate 2 and the back plate 1. Also, since the side of the connecting structure 314 away from the first reflective structure 32 is flush with the end face of the first surface 311 and the diffuser plate 2, the side of the connecting structure 314 away from the first reflective structure 32 can be considered as the first surface 311 extending towards the back plate 1, that is, the first surface 311 is perpendicular to the diffuser plate 2. In this way, the first body 31 can provide the first reflective inclined surface 313 required by the first reflective inclined surface 3s in the inclined part of the middle frame 3, and can also provide support for the inclined part in the vertical part. Thus, the first body 31 can effectively support the back plate 1 and the diffuser plate 2, so there is no need to set the frame 12 at the edge of the back plate 1 to support the middle frame 3, and there is no need to set the mounting hole K on the connecting structure 314, which can effectively simplify the process and improve production efficiency.

[0161] Please see Figures 19-20 This is a schematic diagram of another structure of the middle frame and back plate provided in an embodiment of this disclosure.

[0162] The longitudinal section of the connecting structure 314 is L-shaped;

[0163] In the L-shape, the first part 314a perpendicular to the diffuser plate 2 is 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 near the diffuser plate 2.

[0164] like Figure 19 As shown, the sides of the first part 314a and the second part 314b that are away from the diffuser plate 2 can both be located on the side of the back plate 1 closest to the diffuser plate 2; as Figure 20 As shown, there may be a height difference between the sides of the first part 314a and the second part 314b that are away from the diffuser plate 2. The side of the second part 314b that is away from the diffuser plate 2 is in contact with the side of the back plate 1 that is close to the diffuser plate 2, and the side of the first part 314a that is away from the diffuser plate 2 is flush with the side of the back plate 1 that is away from the diffuser plate 2.

[0165] In the embodiments provided in this disclosure, the longitudinal section of the connecting structure 314 is set to an L-shape; and the first part 314a of the L-shape perpendicular to the diffuser plate 2 is connected to the second surface 312 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, which facilitates the improvement of the support force of the first body 31 on the back plate 1 and the diffuser plate 2, and facilitates the fixing of the connecting mechanism and the back plate 1.

[0166] Please see Figure 21 This is a schematic diagram of another structure of the middle frame and back plate provided in an embodiment of this disclosure.

[0167] The backplate 1 includes a first region A and a second region B surrounding the first region A. The distance h between the portion of the backplate 1 located in the first region A and the diffuser plate 2 is less than the distance h' between the portion of the backplate 1 located in the second region B and the diffuser plate 2.

[0168] The second part is located in the second region B, and the height of the second part is the height difference between the part of the backplate 1 in the first region A and the part in the second region B.

[0169] By setting the back plate 1 to include a first region A and a second region B surrounding the first region A, and making the distance h between the part of the back plate 1 located in the first region A and the diffuser plate 2 less than the distance h' between the part of the back plate 1 located in the second region B and the diffuser plate 2; at the same time, setting the second part of the connecting structure 314 of the middle frame 3 in the second region B of the back plate 1, and making the height of the second part the height difference between the part of the back plate 1 in the first region A and the part in the second region B, the second part and the side of the back plate 1 in the first region A facing the diffuser plate 2 can be located on the same plane. In this way, when the reflective sheet 6 is set on the surface of the back plate 1 and the reflective sheet 6 is bent and extended towards the diffuser plate 2 for reuse as the first reflective structure 32 of the middle frame 3, the flatness of the reflective sheet 6 on the surface of the back plate 1 can be improved, and the light reflected by the reflective sheet 6 can be more uniform.

[0170] It is important to understand that, in Figure 21In the diagram, the light-emitting device 4 is not shown. In practical applications, the reflective sheet 6 may not be provided at the location where the light-emitting device 4 is installed; that is, the position in the reflective sheet 6 corresponding to the position of the light-emitting device 4 can be a through slot exposing the light-emitting device 4. Furthermore, Figure 21 Since it is a cross-sectional view, therefore from Figure 21 The second region B is located on both sides of the first region A; in fact, the second region B surrounds the first region.

[0171] Please see Figure 22 This is a schematic diagram of another structure of the middle frame and back plate provided in an embodiment of this disclosure.

[0172] The second part 314b of the connecting structure 314 also includes a protrusion 314c, which is located on the side surface of the second part 314b near the diffuser plate 2. The end of the protrusion 314c away from the light-emitting device 4 has a gap with the first part 314a.

[0173] The light-emitting device 4 typically includes a circuit board, LEDs, and a lens. The LEDs are 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 LEDs. Multiple light-emitting devices are usually mounted on a single light strip. A single lamp body has a circuit board, multiple LEDs, and lenses corresponding to the LEDs. Multiple light strips are mounted on a backplate 1 to form a backlight. However, the thickness of the circuit board is generally greater than the thickness of the reflector 6. Therefore, this disclosure provides a protrusion 314c on the surface of the second portion 314b near the diffuser plate 2, making the thickness of the protrusion 314c the same as the thickness of the circuit board. This prevents warping at the edge of the portion of the reflector 6 parallel to the diffuser plate 2, keeping it within a plane and further improving the uniformity of the reflected light from the reflector 6.

[0174] Please see Figure 23 and Figure 24 This is a schematic diagram of the structure of a first body provided in an embodiment of this disclosure.

[0175] The first entity 31 also includes:

[0176] The vertical structure 315 is located on the side of the connecting structure 314 closest to the light-emitting device 4, and the side of the vertical structure 315 closest to the light-emitting device 4 is connected to the inclined surface 313. The side of the vertical structure 315 closest to the diffuser plate 2 is connected to the second surface 312, and it is located in the vertical part of the middle frame 3. Figure 23 As shown, the side of the vertical structure 315 closest to the back plate 1 can be fitted against the back plate 1; as Figure 24 As shown, the side of the vertical structure 315 near the back plate 1 can also be connected to the second part of the connecting structure 314.

[0177] In the embodiments provided in this disclosure, by providing a vertical structure 315 on the side of the connecting structure 314 near the light-emitting device 4, and connecting the side of the vertical structure 315 near the light-emitting device 4 to the inclined surface 313, and connecting the side of the vertical structure 315 near the diffuser plate 2 to the second surface 312, the first body 31 can be made more stable. Furthermore, a reflective material can be coated on the side of the vertical portion connected to the inclined surface 313, and a reflective material can be coated on the inclined surface 313 to form a first reflective structure 32. This eliminates the need to bend the reflective sheet 6, thereby reducing manufacturing difficulty and improving production efficiency.

[0178] Please continue. Figure 24 As shown, the first body 31 also includes:

[0179] A transition structure 316 connects the vertical structure 315 and the second surface 312. The side of the transition structure 316 facing the first light-emitting device 4a connects to the inclined surface 313 and the side of the vertical structure 315 facing the first light-emitting device 4a. The side of the transition structure 316 facing the first light-emitting device 4a can be an arc-shaped transition surface, which facilitates a smooth transition of light at the junction of the vertical and inclined portions, effectively improving the uniformity of light.

[0180] Please see Figure 25 This is a schematic diagram of another mid-frame structure provided in an embodiment of the present disclosure. The vertical structure 315 also has an extension 315a, which extends along the end away from the diffuser plate 2 toward the side where the first light-emitting device 4a is located, and the extension 315a is parallel to the diffuser plate 2 and contacts the side of the back plate 1 close to the diffuser plate 2.

[0181] By providing an extension 315a at one end of the vertical structure 315 near 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.

[0182] Please continue reading Figure 25 The backlight module also includes a reflector 6, which is located on the side of the back plate 1 facing the diffuser plate 2. Figure 25 The middle frame 3, which is formed by connecting the vertical structure 315 and the inclined surface 313, is coated with a reflective material to form a reflective film, which constitutes the first reflective structure 32.

[0183] In some embodiments, the first body 31 is integrally formed by injection molding, and the first reflective structure 32 is a reflective film; the first body 31 is integrally formed by injection molding, which makes it easy to manufacture the first body 31 and easy to form complex shapes.

[0184] The first body 31 is made of metal. The reflective sheet 6 located on the surface of the back plate 1 facing the diffuser plate 2 extends along the surface of the first body 31 facing the first light-emitting device 4a to the diffuser plate 2, forming the first reflective structure 32.

[0185] Please see Figure 26 This is a schematic diagram of another backlight module provided in an embodiment of the present invention. The backlight module further includes:

[0186] 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 slope 51, which is used to reflect the third main beam 4a2 formed by the main light emitted by the first light-emitting device 4a towards the side where the second light-emitting device 4b is located, so that the third main beam 4a2 illuminates the surrounding area where the middle frame 3 and the diffuser plate 2 abut, and the second reflective structure 5 does not block the second main beam 4b1 emitted by the second light-emitting device 4b towards the side of the first light-emitting device 4a.

[0187] like Figure 26 As shown, when the first light-emitting device 4a sends the third main beam 4a2 towards the second light-emitting device 4b, it is reflected by the second reflective slope 51 of the second reflective structure 5 and illuminates the surrounding area where the middle frame 3 and the diffuser plate 2 abut. This increases the brightness of the surrounding area (i.e., the edge area of ​​the backlight module) and improves the dark bands at the edge of the backlight module. When the backlight module is used as a splicing screen, the improvement in the dark bands at the splicing position also improves the dark bands at the splicing position. Furthermore, since the second reflective structure 5 does not block the second main beam 4b1 emitted by the second light-emitting device 4b towards the first light-emitting device 4a, the second main beam 4b1 can reach the diffuser plate 2 smoothly without shadows, thus effectively improving the display effect.

[0188] Please continue reading Figure 26 The second reflective structure 5 also includes:

[0189] Vertical surface 52 faces the second light-emitting device 4b and intersects with the second reflective inclined surface 51;

[0190] 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.

[0191] The vertical surface 52 of the second reflective structure 5 is non-reflective, which reduces the reflection of light. The second reflective inclined surface 51 can reflect light by coating it with a reflective material or by attaching a reflective film layer to the second reflective inclined surface 51. There are no specific restrictions.

[0192] Please see Figure 27An optical path diagram of a third master beam is provided for an embodiment of this disclosure.

[0193] The height H of the vertical surface 52 of the second reflective structure 5 satisfies the following: the main light emitted by the first light-emitting device 4a at the minimum main emission angle α toward the second reflective inclined surface 51 reaches the diffuser plate 2 after being reflected by the reflective surface, and the vertical surface 52 does not block the second main beam 4b1 emitted by the second light-emitting device 4b toward the side of the first light-emitting device 4a at the maximum main emission angle β'.

[0194] The angle γ between the second reflecting slope 51 and the vertical surface 52 of the second reflecting structure 5 satisfies the following condition: the main ray emitted by the first light-emitting device 4a at its maximum main emission angle β towards the second reflecting slope 51 intersects with the second reflecting slope 51 and reaches the middle frame 3 after reflection by the reflecting surface. In the extreme case, the intersection point of the main ray emitted by the first light-emitting device 4a at its maximum main emission angle β towards the reflecting surface and the second reflecting slope 51 of the second reflecting structure 5 is exactly the intersection point of the second reflecting slope 51 and the vertical surface 52 of the second reflecting structure 5.

[0195] In the embodiments provided in this disclosure, by setting the height H of the vertical surface 52 of the second reflective structure 5 to satisfy the following: the main light emitted by the first light-emitting device 4a towards the second reflective inclined surface 51 at the minimum main emission angle α reaches the diffuser plate 2 after being reflected by the second reflective inclined surface 51; and by setting the angle γ between the second reflective inclined surface 51 and the vertical surface 52 of the second reflective structure 5 to satisfy the following: the main light emitted by the first light-emitting device 4a towards the second reflective inclined surface 51 at the maximum main emission angle β reaches the middle frame 3 after being reflected by the second reflective inclined surface 51, it is possible to... The third main beam 4a2 emitted by the first light-emitting device 4a towards the second reflective inclined surface 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 enhancing the brightness of the surrounding area where the middle frame 3 and the diffuser plate 2 abut. Meanwhile, the vertical surface 52 does not block the second main beam 4b1 emitted by the second light-emitting device 4b towards the first light-emitting device 4a at the maximum main emission angle β', so that the second main beam emitted by the second light-emitting device 4b towards the first light-emitting device 4a is not blocked by the second reflective structure 5, preventing the formation of shadow areas.

[0196] Please continue reading Figure 27 The included angle γ satisfies the following constraints:

[0197] tan(180°+b1-2γ)≥(L5-H1) / (L3-L5);

[0198] tan(180°+c1-2γ)≤(OD-H) / (L1+L3);

[0199] Where, L5 = L3(tanc1-tanb1) / (tanγ-tanb1); L5 is the distance from the intersection of the main ray emitted by the first light-emitting device 4a at the maximum main emission angle β to the second reflective structure 5 and the second reflective inclined surface 51 to the vertical surface 52;

[0200] H1 = L3 × tanc - L3 × tanγ (tanc1 - tanb1) / (tanγ - tanb1); H1 is the distance from the point where the main light emitted by the first light-emitting device 4a at the maximum main emission angle β towards the second reflective structure 5 intersects with the second reflective inclined surface 51 to the back plate 1.

[0201] γ is the included angle, b1 is the complementary angle of the maximum principal emission angle β of the first light-emitting device 4a (i.e., b1 = 90° - β), c1 is the complementary angle of the minimum principal emission 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.

[0202] The height H of the vertical plane 52 satisfies the following constraints:

[0203] H=(L2-L3)×tanb1=L3×tanc1;

[0204] Where H is the height of the vertical plane 52 (i.e., the height of the second reflective structure 5).

[0205] The second reflective structure 5 can be fixed to the back plate 1 by adhesive bonding, or by setting a through hole K' on the back plate 1 and setting 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 plate 1 by screws.

[0206] Please see Figure 28 This is a schematic diagram of a second reflective structure provided in an embodiment of the present disclosure. The second reflective structure 5 further includes:

[0207] Multiple fixing structures 54, one end of which is connected to the bottom surface 53 of the second reflective structure 5, and the other end of which has a hook extending in the direction of the second reflective structure 5.

[0208] The fixing structure 54 can be a snap-on type.

[0209] By providing multiple fixing structures 54 on the bottom surface 53 of the second reflective structure 5, and having the fixing structure 54 have a hook extending in the direction of the second reflective structure 5 at the end away from the second reflective structure 5, it is convenient to fix the second reflective structure 5 to the back plate 1.

[0210] In some embodiments, the second reflective structure 5 and the plurality of fixing structures 54 are integrally molded using an injection molding process, which facilitates the production of the second reflective structure 5.

[0211] Example 1

[0212] The tilt angle of the middle frame 3 in an existing backlight module is optimized. Specifically, the light mixing distance (i.e., the distance between the back panel 1 and the diffuser 2) of the backlight module is OD = 30mm, the distance L1 between the first light-emitting device 4a and the inner sidewall of the middle frame 3 is 32mm, the center distance L2 between the first light-emitting device 4a and the second light-emitting device 4b is 60.5mm, and the brightness curve of the light-emitting device 4 used in the backlight module is as follows: Figure 3 As shown, in the original scheme, the tilt angle δ of the first reflective inclined surface 3s of the backlight module is 61°. Now, the scheme provided in this disclosure, which changes the tilt angle δ of the first reflective inclined surface 3s, is adopted. Figure 3 It can be seen that the minimum principal emission angle of the light-emitting device 4 is 60° and the maximum principal emission angle is 80°, that is, α=α'=60° and β=β'=80°. According to the aforementioned formula for the range of the tilt angle δ of the first reflecting slope 3s, the range of δ can be determined to be 31.5°≤δ≤42°. Therefore, δ is changed from 61° in the original scheme to 35°. Figure 29 The diagram shown illustrates the modification of the tilt angle of the first reflective surface according to an embodiment of this disclosure. After optimization using the solution provided in this disclosure, by measuring the brightness within an 80mm radius of the backlight module edge, the brightness drop point at the edge decreases from 15mm to 5mm. Figure 30 The figure shows the edge brightness curves before and after backlight module optimization.

[0213] When the optimized backlight module is used to form a splicing screen, the dark frame at the edge of the splicing seam is improved, and the visual splicing seam will not be affected when viewed from a distance.

[0214] Example 2

[0215] Based on Example 1, a second reflective structure 5 is added between the first light-emitting device 4a and the second light-emitting device 4b. According to the above scheme provided in this 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 is 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 is 20.3, and the tilt angle (i.e., the first included 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: in Example 1, the brightness begins to decrease at 6mm from the edge of the tube module, the brightness in the edge area is slightly increased, and the dark frame is narrowed; in Example 2, the brightness begins to decrease at 3mm from the edge of the backlight module, with no bright band or dark frame.

[0216] When the first and second light-emitting devices use light-emitting devices with the same parameters, their maximum principal emission angle is the same (i.e., β=β') and their minimum principal emission angle is also the same (i.e., α=α'). If they use light-emitting devices with different parameters, their maximum principal emission angle may be different and their minimum principal emission angle may be the same.

[0217] It should be understood that the above examples are merely illustrative of the verification process for a portion of the solutions disclosed herein. The verification of other solutions not shown can be performed in a similar manner, and will not be described in detail here.

[0218] Based on the same inventive concept, embodiments of this disclosure provide a display device, which includes:

[0219] The backlight module as described above; the backlight module is a direct-lit backlight module.

[0220] The display panel is located on the light-emitting surface of the backlight module.

[0221] The display device can be a liquid crystal display, liquid crystal screen, liquid crystal television, or other display devices, or a mobile device such as a mobile phone, tablet computer, or laptop.

[0222] Although preferred embodiments of this disclosure have been described, those skilled in the art, upon learning the basic inventive concept, can make other changes and modifications to these embodiments. Therefore, the appended claims are intended to be interpreted as including the preferred embodiments as well as all changes and modifications falling within the scope of this disclosure.

[0223] Obviously, those skilled in the art can make various modifications and variations to this disclosure without departing from its spirit and scope. Therefore, if such modifications and variations fall within the scope of the claims of this disclosure and their equivalents, this disclosure is also intended to include such modifications and variations.

Claims

1. A backlight module, comprising: A back plate and a diffuser plate are arranged opposite to each other, and a middle frame is arranged along the edge region of the back plate, the middle frame abutting against the diffuser plate; Multiple light-emitting devices are located on the side of the back plate facing the diffuser plate; among the multiple light-emitting devices, the outermost light-emitting device is the first light-emitting device, and the light-emitting device closest to the first light-emitting device in the first direction of the middle frame pointing towards the first light-emitting device is the second light-emitting device; The distance between the first light-emitting device and the inner sidewall of the middle frame, and the distance between the first light-emitting device and the second light-emitting device, satisfy the following conditions: the first main light beam emitted by the first light-emitting device toward the middle frame is reflected by the middle frame and projected onto the projection position of the first light-emitting device and the second light-emitting device, and the second main light beam emitted by the second light-emitting device toward the middle frame passes through the contact position between the middle frame and the diffuser plate.

2. The backlight module as described in claim 1, wherein the distance between the second light-emitting device and the inner sidewall of the middle frame satisfies the following conditions: at least the main light emitted by the second light-emitting device towards the first light-emitting device at the minimum main emission angle passes through the contact position; or at least the main light emitted by the second light-emitting device towards the first light-emitting device at the maximum main emission angle passes through the contact position.

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

4. The backlight module as described in claim 3, wherein the distance between the first light-emitting device and the inner sidewall of the middle frame ranges from 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 principal emission angle of the first light-emitting device, and c1 is the complementary angle of the minimum principal emission angle of the first light-emitting device. The distance between the first light-emitting device and the second light-emitting device is in the 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 as described in claim 2, 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 sidewall of the middle frame.

6. The backlight module as described in claim 1 or 2, 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 is in contact with the back plate; the inclined portion has a first reflective inclined surface facing the side where the first light-emitting device is located and abuts against the diffuser plate; The tilt angle of the first reflecting slope satisfies the following conditions: the second main beam is at least partially projected onto the first reflecting slope, and the second main beam is perpendicular to the diffuser after being reflected by the first reflecting slope; or, the edge of the second main beam passes through the contact position between the first reflecting slope and the diffuser.

7. The backlight module as described in 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 emission angle of the second light-emitting device, and b2 is the complementary angle of the maximum main emission angle of the second light-emitting device.

8. The backlight module as described in claim 6, wherein the middle frame has a supporting surface at the position where it abuts against the diffuser plate, and the supporting surface is parallel to the diffuser plate.

9. The backlight module as claimed in claim 8, wherein the length of the orthographic projection of the first reflective slope onto the diffuser plate in the first direction satisfies the following: the third main beam emitted by the first light-emitting device toward the middle frame side is projected onto the vertical portion, such that the third main beam is reflected by the vertical portion and then projected onto the area of ​​the diffuser plate corresponding to the area between the first light-emitting device and the second light-emitting device.

10. The backlight module as described in 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 plate, L1 is the distance between the first light-emitting device and the middle frame, c1 is the complementary angle of the minimum main emission angle of the first light-emitting device, and δ is the tilt angle of the first reflective slope.

11. The backlight module as claimed in claim 6, wherein the middle frame comprises: A first body is located in the inclined portion. The first body has a first surface, a second surface, and a connection structure connected to the inclined surface in sequence. The first surface intersects with the diffuser plate, the second surface is parallel to the diffuser plate and does not contact it, and the inclined surface is located on the 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 the side of the first body close to the first light-emitting device. A portion of the first reflective structure is located in the inclined portion, and another portion is located in the vertical portion.

12. The backlight module as claimed in claim 11, wherein the end of the connecting structure away from the diffuser plate is not in contact with the side of the back plate facing the diffuser plate, and the connecting structure has a mounting hole in the first direction; The backplate includes: The second body is parallel to the diffuser plate; The frame extends along the edge of the second body toward the diffuser plate to the side of the connecting structure away from the first light-emitting device; the frame has a through hole at the position corresponding to the mounting hole, and the connector passes through the through hole and is fixedly connected to the frame and the connecting structure with the mounting hole.

13. The backlight module as claimed in claim 12, wherein in the second direction in which the diffuser plate points to the back plate, the frame has bent portions at both ends of the through hole, and the through hole is provided with threads.

14. The backlight module as claimed in claim 11, wherein the connection structure extends from the second surface to the side of the back plate facing the diffuser plate and is perpendicular to the second surface; The end of the connecting structure away from the diffuser plate abuts against the back plate, and the side of the connecting structure away from the first reflective structure is flush with the first surface and the end face of the diffuser plate.

15. The backlight module as described in claim 14, wherein the longitudinal cross-sectional shape of the connecting structure is L-shaped; The first part of the L-shape perpendicular to the diffuser plate is connected to the second surface at one end away from the second part parallel to the diffuser plate, and the second part is located on the side surface of the back plate close to the diffuser plate.

16. The backlight module of claim 15, wherein the backplate includes a first region and a second region surrounding the first region, and the distance between the portion of the backplate located in the first region and the diffuser plate is less than the distance between the portion of the backplate located in the second region and the diffuser plate; The second part is located in the second region, and the height of the second part is the height difference between the portion of the back plate in the first region and the portion in the second region.

17. The backlight module of claim 16, wherein the second portion further comprises a protrusion located on the side surface of the second portion near the diffuser plate.

18. The backlight module as claimed in claim 11, wherein the first body further comprises: A vertical structure is located on the side of the connecting structure closer to the light-emitting device, and the side of the vertical structure closer to the light-emitting device is connected to the inclined surface, and the side of the vertical structure closer to the diffuser plate is connected to the second surface.

19. The backlight module of claim 18, wherein the vertical structure further comprises an extension, the extension extending along one end away from the diffuser towards the side where the first light-emitting device is located, and the extension is parallel to the diffuser and contacts the side of the back plate close to the diffuser.

20. The backlight module as described in claim 18, wherein the first body further comprises: A transition structure is provided between the vertical structure and the second surface. The side of the transition structure facing the first light-emitting device is connected between the inclined surface and one side of the vertical structure, and one side of the vertical structure faces the side where the first light-emitting device is located.

21. The backlight module of claim 11, further comprising a reflective sheet located on the side of the back plate facing the diffuser plate.

22. The backlight module as described in 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, and the reflective sheet located on the back plate facing the diffuser plate extends along the surface of the first body facing the first light-emitting device to the diffuser plate to form the first reflective structure.

23. The backlight module as described in claim 1 or 2, wherein the backlight module further comprises: The second reflective structure is fixed to the 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 the third main beam formed by the main light emitted by the first light-emitting device toward the side where the second light-emitting device is located, so that the third main beam illuminates the area around the middle frame and the diffuser plate, and the second reflective structure does not block the second main beam.

24. The backlight module of claim 23, wherein the second reflective structure further comprises: A vertical surface, which faces the second light-emitting device and intersects with the second reflective inclined surface; The bottom surface, located on the side of the back plate facing the diffuser plate, connects the vertical surface and the second reflective slope.

25. The backlight module as described in claim 24, wherein the height of the vertical surface satisfies the following conditions: the main light emitted by the first light-emitting device at the minimum main emission angle toward the second reflective inclined surface reaches the diffuser plate 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 emission angle toward the side of the first light-emitting device; The angle between the second reflective slope and the vertical plane satisfies the following condition: the main light rays emitted by the first light-emitting device at the maximum main emission angle intersect with the second reflective slope and reach the middle frame after being reflected by the second reflective slope.

26. The backlight module as described in claim 25, wherein the included angle satisfies the following constraint relationship: 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 included angle, b1 is the complementary angle of the maximum principal emission angle of the first light-emitting device, c1 is the complementary angle of the minimum principal emission 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 plate and the diffuser plate.

27. The backlight module as described in claim 25, wherein the height of the vertical surface satisfies the following constraint: H=(L2-L3)×tanb1=L3×tanc1; in, H is the height of the vertical plane.

28. The backlight module of claim 24, wherein the second reflective structure further comprises: Multiple fixed structures are provided, one end of which is connected to the bottom surface of the second reflective structure, and the other end has a hook extending in the direction of the second reflective structure.

29. The backlight module as described in claim 28, wherein the second reflective structure and the plurality of fixed structures are integrally formed by injection molding.

30. A display device, comprising: The backlight module as described in any one of claims 1-29; The display panel is located on the light-emitting surface of the backlight module.

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