Backlight module and display apparatus

1 . A backlight module, comprising:

a backboard and a diffusion plate arranged opposite to each other, and a middle bezel arranged along an edge region of the backboard, wherein the middle bezel abuts against the diffusion plate; and

a plurality of light-emitting devices on a side of the backboard facing the diffusion plate; wherein the light-emitting device located on an outermost side among the plurality of light-emitting devices is a first light-emitting device; and in a first direction of the middle bezel pointing toward the first light-emitting device, the light-emitting device nearest the first light-emitting device is a second light-emitting device;

wherein a distance between the first light-emitting device and an inner side wall of the middle bezel, and a distance between the first light-emitting device and the second light-emitting device meet that: a first major light beam emitted by the first light-emitting device toward the middle bezel is reflected by the middle bezel and then projected to a position between an orthographic projection of the first light-emitting device on the diffusion plate and an orthographic projection of the second light-emitting device on the diffusion plate, and a second major light beam emitted by the second light-emitting device toward the middle bezel passes through an abutting position of the middle bezel and the diffusion plate.

2 . The backlight module according to claim 1 , wherein a distance between the second light-emitting device and the inner side wall of the middle bezel meets that:

at least a main light ray emitted by the second light-emitting device toward a side of the first light-emitting device at a minimum main light-emitting angle passes through the abutting position; or,

at least a main light ray emitted by the second light-emitting device toward a side of the first light-emitting device at a maximum main light-emitting angle passes through the abutting position.

3 . The backlight module according to claim 1 or claim 2 , wherein a distance between the second light-emitting device and the inner side wall of the middle bezel ranges from OD/tan c 2 to OD/tan b 2 ;

wherein OD is spacing between the backboard and the diffusion plate, b 2 is a complement angle of a maximum main light-emitting angle of the second light-emitting device, and c 2 is a complement angle of a 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 side wall of the middle bezel is in a range of 1/3 OD/tan c 1 ≤L1≤1/3 OD/tan b 1 ; wherein L1 is the distance between the first light-emitting device and the inner side wall of the middle bezel; b 1 is a complement angle of a maximum main light-emitting angle of the first light-emitting device; and c 1 is a complement angle of a minimum main light-emitting angle of the first light-emitting device;

wherein the distance between the first light-emitting device and the second light-emitting device is in a range of 2/3 OD/tan c 2 ≤L2≤2/3 OD/tan b 2 ; wherein L2 is the distance between the first light-emitting device and the second light-emitting device.

5 . The backlight module according to claim 2 , wherein the distance between the first light-emitting device and the second light-emitting device is two times the distance between the first light-emitting device and the inner side wall of the middle bezel.

6 . The backlight module according to claim 1 , wherein the middle bezel has an inclined part and a vertical part;

wherein the vertical part is located between the inclined part and the backboard and is in contact with the backboard; and the inclined part has a first reflection bevel toward a side where the first light-emitting device is located and abuts against the diffusion plate;

wherein an inclination angle of the first reflection bevel meets that: the second major light beam is at least partially projected on the first reflection bevel, and the second major light beam after being reflected by the first reflection bevel is perpendicular to the diffusion plate; or, an edge of the second major light beam passes through the abutting position of the first reflection bevel and the diffusion plate;

wherein a range of the inclination angle is:

(90°− c 2)/2≤δ≤(90°− b 2)/2;

wherein δ is the inclination angle, c2 is a complement angle of a minimum main light-emitting angle of the second light-emitting device, and b2 is a complement angle of a maximum main light-emitting angle of the second light-emitting device.

7 . The backlight module according to claim 6 , wherein a length of an orthographic projection of the first reflection bevel on the diffusion plate in the first direction meets that: a first major light beam emitted by the first light-emitting device toward a side of the middle bezel is projected on the vertical part, and the first major light beam after being reflected by the vertical part is projected on a position of the diffusion plate corresponding to a region between the first light-emitting device and the second light-emitting device;

and/or,

a length of the first reflection bevel in the first direction is: L4=(OD−L1×tan c 1 )×tan δ; wherein L4 is the length of the first reflection bevel in the first direction, OD is spacing between the backboard and the diffusion plate, L1 is the distance between the first light-emitting device and the middle bezel, c1 is a complement angle of a minimum main light-emitting angle of the first light-emitting device, and δ is the inclination angle of the first reflection bevel.

8 . The backlight module according to claim 6 , wherein the middle bezel comprises:

a first body of the inclined part; wherein the first body has a first face, a second face, a bevel and a connection structure connected sequentially; the first face intersects with the diffusion plate;

the second face is parallel to and not in contact with the diffusion plate; the bevel is located on a side of the first face close to the first light-emitting device, and an end of the bevel abuts against the diffusion plate; and the connection structure extends from the second face toward a side of the backboard, and is perpendicular to the second face; and

a first reflection structure on a side of the first body close to the first light-emitting device, wherein one part of the first reflection structure belongs to the inclined part, and the other part of the first reflection structure belongs to the vertical part.

9 . The backlight module according to claim 8 , wherein an end of the connection structure away from the diffusion plate is not in contact with a side of the backboard facing the diffusion plate, and the connection structure has a mounting hole in the first direction;

wherein the backboard comprises: a second body parallel to the diffusion plate; and a frame, along an edge of the second body, extending toward the diffusion plate to arrive at a side of the connection structure away from the first light-emitting device, wherein the frame has a through hole penetrating through the frame at a position corresponding to the mounting hole, and a connection member passes through the through hole and the mounting hole to fixedly connect the frame to the connection structure;

and/or,

the connection structure extends from the second face to a side of the backboard facing the diffusion plate and is perpendicular to the second face; and an end of the connection structure away from the diffusion plate abuts against the backboard, and a surface of the connection structure away from the first reflection structure is flush with the first face and an end face of the diffusion plate.

10 . The backlight module according to claim 9 , wherein a longitudinal profile of the connection structure is in an L shape; and

an end, away from a second part parallel to the diffusion plate, of a first part of the L shape perpendicular to the diffusion plate is connected to the second face; and the second part is located on a side of the backboard close to the diffusion plate;

wherein the backboard comprises a first region and a second region surrounding the first region, and a distance between a part of the backboard in the first region and the diffusion plate is less than a distance between a part of the backboard in the second region and the diffusion plate; and

the second part is located in the second region, and a height of the second part is a height difference between the part of the backboard in the first region and the part of the backboard in the second region;

wherein the second part further comprises a protrusion, and the protrusion is located on a side of the second part close to the diffusion plate.

11 . The backlight module according to claim 8 , wherein the first body further comprises:

a vertical structure on a side of the connection structure close to the light emitting device, wherein a side of the vertical structure close to the light emitting device is connected to the bevel, and a side of the vertical structure close to the diffusion plate is connected to the second face.

12 . The backlight module according to claim 11 , wherein the vertical structure further has an extending portion;

wherein an end of the extending portion away from the diffusion plate extends toward the side where the first light-emitting device is located; and

the extending portion is parallel to the diffusion plate and in contact with a side of the backboard close to the diffusion plate.

13 . The backlight module according to claim 11 , wherein the first body further comprises:

a transition structure, connected between the vertical structure and the second face, wherein a side of the transition structure facing the side where the first light-emitting device is located is connected between the bevel and a side of the vertical structure, and the side of the vertical structure facing the side where the first light-emitting device is located.

14 . The backlight module according to claim 8 , wherein the backlight module further comprises a reflection sheet, and the reflection sheet is located on a side of the backboard facing the diffusion plate;

and/or,

the first body is integrally formed by adopting an injection molding process, and the first reflection structure is a reflection film; and a material adopted by the first body is a metal, and the reflection sheet on the side of the backboard facing the diffusion plate extends along a surface of the first body facing the side where the first light-emitting device is located to the diffusion plate, to form the first reflection structure.

15 . The backlight module according to claim 1 , further comprising:

a second reflection structure, fixed to the side of the backboard facing the diffusion plate, and located between the first light-emitting device and the second light-emitting device; wherein the second reflection structure has a second reflection bevel, and the second reflection bevel is used for reflecting a third major light beam formed by main light rays emitted by the first light-emitting device toward a side where the second light-emitting device is located, the third major light beam illuminates a region surrounding a position where the middle bezel abuts against the diffusion plate, and the second reflection structure does not block the second major light beam.

16 . The backlight module according to claim 15 , wherein the second reflection structure further comprises: a vertical face, facing the second light-emitting device and intersecting with the second reflection bevel; and a bottom face, located on the side of the backboard facing the diffusion plate, and connecting the vertical face to the second reflection bevel;

and/or,

the second reflection structure further comprises: a plurality of fixing structures, one end of each the plurality of fixing structures is connected to the bottom face of the second reflection structure, and the other end of each fixing structure has a hook extending in a direction where the second reflection structure is located; wherein the second reflection structure and the plurality of fixing structures are integrally formed by adopting an injection molding process.

17 . The backlight module according to claim 16 , wherein a height of the vertical face meets that: a main light ray emitted by the first light-emitting device toward the second reflection bevel at a minimum main light-emitting angle arrives at the diffusion plate after being reflected by the second reflection bevel; and the vertical face does not block a main light ray emitted by the second light-emitting device toward the side of the first light-emitting device at a maximum main light-emitting angle; and

an included angle of the second reflection bevel and the vertical face meets that: a main light ray emitted by the first light-emitting device toward the second reflection bevel at a maximum main light-emitting angle intersects with the second reflection bevel, and arrives at the middle bezel after being reflected by the second reflection bevel.

18 . The backlight module according to claim 17 , wherein the included angle meets following constraints:

tan (180°+b 1 −2γ)≥(L5−H1)/(L3−L5); and

tan (180°+c 1 −2γ)≤(OD−H)/(L1+L3);

wherein L5=L3 (tan c 1 −tan b 1 )/(tan γ−tan b 1 ); and

H1=L3×tan c−L3×tan γ(tan c 1 −tan b 1 )/(tan γ−tan b 1 );

wherein γ is the included angle, b 1 is a complement angle of the maximum main light-emitting angle of the first light-emitting device, c 1 is a complement angle of the minimum main light-emitting angle of the first light-emitting device, L1 is a distance between the first light-emitting device and the middle bezel, L2 is a distance between the first light-emitting device and the second light-emitting device, L3 is a distance between the first light-emitting device and the vertical face, the vertical face is parallel to a centerline of the first light-emitting device, H is the height of the vertical face, and OD is spacing between the backboard and the diffusion plate.

19 . The backlight module according to claim 17 , wherein the height of the vertical face meets a following constraint:

H =( L 2− L 3)×tan b 1 =L 3×tan c 1 ;

wherein H is the height of the vertical face.

20 . A display apparatus, comprising:

the backlight module according to claim 1 ; and

a display panel on a light emergence surface of the backlight module.