Backlight module

Abstract

This invention discloses a backlight module, including a reflective element, multiple light-emitting elements, and a light diffuser plate. The reflective element has a first surface, a second surface, and multiple light source slots. The first surface and the second surface are opposite to each other. The light source slots extend from the first surface toward the second surface and each has a light-emitting port located on the first surface. The multiple light-emitting elements are respectively disposed within the light source slots. The light diffuser plate is disposed opposite to the first surface, wherein the distance between the light diffuser plate and the first surface is between 0.5 mm and 4 mm.

Description

Technical Field

[0001] This invention relates to a light source module, and more particularly to a backlight module. Background Technology

[0002] A liquid crystal display (LCD) mainly consists of a backlight module, a display panel, and a frame. Specifically, backlight modules can be divided into edge-lit backlight modules and direct-lit backlight modules. Direct-lit backlight modules, with their surface light source, offer the advantage of uniform brightness and facilitate local dimming, resulting in better image contrast. Therefore, most large LCDs that use light-emitting diodes (LEDs) as their light source employ direct-lit backlight modules.

[0003] However, existing backlight modules cannot effectively control the light emission angle of the light-emitting elements. Therefore, when performing local dimming, the light emitted from the bright area in existing backlight modules will interfere with the adjacent dark area, thus affecting the display effect of the dark area and reducing the contrast of the image. Summary of the Invention

[0004] This invention provides a backlight module with the advantages of a small light emission angle and uniform light emission brightness.

[0005] To achieve one or more of the above-mentioned objectives, or other objectives, the backlight module provided by the present invention includes a reflective element, a plurality of light-emitting elements, and a light diffuser plate. The reflective element has a first surface, a second surface, and a plurality of light source slots. The first surface and the second surface are opposite to each other. The light source slots extend from the first surface toward the second surface and each has a light-emitting opening located on the first surface. The plurality of light-emitting elements are respectively disposed within the light source slots. The light diffuser plate is disposed opposite to the first surface, wherein the distance between the light diffuser plate and the first surface is between 0.5 mm and 4 mm.

[0006] In one embodiment of the present invention, the backlight module further includes, for example, a support element. The support element is fixed to the reflective element and abuts against the light diffuser plate, such that there is a distance between the light diffuser plate and the first surface.

[0007] In one embodiment of the invention, the first surface described above has an outer edge that surrounds the light exit port. A support element can be fixed to the reflective element along the outer edge.

[0008] In one embodiment of the present invention, the above-mentioned support element and reflective element may be an integral structure or a separate structure.

[0009] In one embodiment of the present invention, the materials of the support element and the reflective element may include rubber, polycarbonate, polypropylene, polyethylene terephthalate or polyethylene.

[0010] In one embodiment of the present invention, the aforementioned light source slots each have a bottom and a reflective portion. The bottoms are respectively opposite to the light emission ports and are adapted to accommodate light-emitting elements. The reflective portion is located between the light emission port and the bottom and is adapted to surround the light-emitting element. The reflective portion includes a first reflective surface and a second reflective surface. The first reflective surface is located between the second reflective surface and the bottom, and the second reflective surface is located between the first reflective surface and the light emission port. The slope of the first reflective surface relative to the second surface may be less than the slope of the second reflective surface relative to the second surface, or the curvature of the first reflective surface may be greater than the curvature of the second reflective surface.

[0011] In one embodiment of the present invention, the light-emitting elements described above each have a top surface and a bottom surface. The top surface and the bottom surface are opposite to each other, and the top surface faces the light-emitting port. The top surface has a normal direction, and the angle between the peak angle of the light intensity emitted by each light-emitting element and the normal direction is between 50 degrees and 90 degrees, and the beam angle of the light-emitting element is between 140 degrees and 180 degrees.

[0012] In one embodiment of the present invention, the backlight module may further include a plurality of light-shielding elements. The light-emitting element has a top surface and a bottom surface. The top and bottom surfaces face each other, with the top surface facing the light outlet. The light-shielding elements are respectively disposed on the top surface.

[0013] In one embodiment of the present invention, the included angle is, for example, between 50 degrees and 70 degrees.

[0014] In one embodiment of the present invention, the beam angle of each of the above-mentioned light-emitting elements is, for example, between 140 degrees and 180 degrees.

[0015] In one embodiment of the present invention, the above-mentioned light-emitting elements each have a top surface and a bottom surface. The top surface and the bottom surface are opposite to each other, and the top surface faces the light-emitting port. The top surface has a normal, and the angle between the peak angle of the light intensity of each light-emitting element and the normal can be between -5 degrees and 5 degrees, and the beam angle of each light-emitting element can be between 120 degrees and 140 degrees.

[0016] In one embodiment of the present invention, two adjacent light-emitting ports in the above-mentioned light-emitting ports are spaced apart on the first surface, and the spaced apart can be between 0.01 mm and 2 mm.

[0017] In one embodiment of the present invention, the light diffuser plate has a light-emitting surface and a light-incident surface, the light-emitting surface facing away from the first surface and opposite to the light-incident surface. The light-emitting surface and / or the light-incident surface may have multiple optical microstructures.

[0018] In one embodiment of the invention, each of the aforementioned optical microstructures has an inclined surface. The inclined surface stands on the light-emitting surface and / or the light-receiving surface, and is inclined relative to the light-emitting and light-receiving surfaces. The two inclined surfaces of two adjacent optical microstructures face each other, and the two inclined surfaces are adjacent to each other by a connecting line. An angle between the two inclined surfaces is between 30 degrees and 150 degrees. The connecting lines of four adjacent optical microstructures intersect at the intersection point, and eight adjacent optical microstructures are adjacent to each other around the intersection point.

[0019] In one embodiment of the present invention, the shape of the optical microstructure described above may include a triangular pyramid, a square pyramid, a triangular prism, a cylinder, a cone, or a sphere.

[0020] In one embodiment of the present invention, the backlight module further includes, for example, an optical film disposed on the side of the light diffuser opposite to the reflective element.

[0021] The backlight module of this invention employs a reflective element and a light diffuser plate. Light generated by the light-emitting element is reflected by the reflective element and emitted from it at a relatively small exit angle. Furthermore, because the distance between the light diffuser plate and the first surface of the reflective element is between 0.5 mm and 4 mm, light emitted from the reflective element enters the light diffuser plate at a smaller angle, further reducing the angle at which the light exits the light diffuser plate. Based on this structure, the backlight module of this invention has the advantages of a small exit angle and uniform light output brightness, thereby improving the brightness contrast of the dimming area in the backlight module's execution region.

[0022] To make the above and other objects, features and advantages of the present invention more apparent and understandable, specific embodiments are described below in conjunction with the accompanying drawings. Attached Figure Description

[0023] Figure 1 This is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention.

[0024] Figure 2 yes Figure 1 A top view of the reflective and supporting elements.

[0025] Figure 3 yes Figure 1 A schematic diagram of the light pattern distribution of the light-emitting element at horizontal and vertical viewing angles.

[0026] Figure 4 This is a three-dimensional schematic diagram of the optical microstructure of a backlight module according to another embodiment of the present invention.

[0027] Figure 5 yes Figure 4 A cross-sectional view of the optical microstructure along section AA.

[0028] Figure 6 This is a top view schematic diagram of the optical microstructure of the backlight module according to another embodiment of the present invention.

[0029] Figure 7 yes Figure 6 A cross-sectional view of the optical microstructure along the BB section.

[0030] Figure 8 This is a top view schematic diagram of the optical microstructure of the backlight module according to another embodiment of the present invention.

[0031] Figure 9 This is a cross-sectional schematic diagram of the optical microstructure of a backlight module according to another embodiment of the present invention.

[0032] Figure 10 This is a cross-sectional schematic diagram of the optical microstructure of a backlight module according to another embodiment of the present invention.

[0033] Figure 11 This is a cross-sectional schematic diagram of a backlight module according to another embodiment of the present invention.

[0034] Figure 12 yes Figure 11 A schematic diagram of the light pattern distribution of the light-emitting element.

[0035] Figure 13 This is a schematic diagram of the light pattern distribution of the light-emitting element of the backlight module according to another embodiment of the present invention.

[0036] Figure 14 This is a cross-sectional schematic diagram of a backlight module according to another embodiment of the present invention.

[0037] In the attached figures, the following labels are used:

[0038] 100, 100a, 100b: Backlight modules

[0039] 110, 110a, 110b: Reflective elements

[0040] 111: First Surface

[0041] 112, 112a, 112b: Second surface

[0042] 113, 113a, 113b: Light source slots

[0043] 120: Light-emitting element

[0044] 121: Top surface

[0045] 122: Bottom surface

[0046] 123: Side view

[0047] 130: Light diffusion plate

[0048] 131: Exposed surface

[0049] 132: Light-receiving surface

[0050] 140: Support element

[0051] 150: Optical film

[0052] 160: Light-shielding element

[0053] 1131, 1131a, 1131b: Bottom

[0054] 1132, 1132b: Reflecting part

[0055] 1310, 1310a, 1310b, 1310c, 1310d: Optical microstructures

[0056] 1310: Optical Microstructure

[0057] 1311: Incline

[0058] 1312: Connection

[0059] A': angle

[0060] A: Angle

[0061] A1:Angle

[0062] BA, BA1: Beam angle

[0063] C: Cone

[0064] C1, C2: Curvature

[0065] CS: Surface

[0066] D: Distance

[0067] FS: Plane

[0068] G: Spacing

[0069] H1, H2: Height

[0070] HS: Hemisphere

[0071] L, L1, L2: Light rays

[0072] N: Normal direction

[0073] O: light outlet

[0074] OE: Outer edge

[0075] OS: Outer side

[0076] P: Intersection point

[0077] Q: Four-cornered pyramid

[0078] R1, R2: Radius

[0079] RS1, RS1b: First reflecting surface

[0080] RS2, RS2b: Second reflecting surface

[0081] S1, S2: Slope

[0082] SS: spherical

[0083] Ta: Triangular pyramid

[0084] TA: Sharp corner Detailed Implementation

[0085] The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments, but this is not intended to limit the present invention.

[0086] Figure 1 This is a cross-sectional schematic diagram of a backlight module according to an embodiment of the present invention. Figure 2 yes Figure 1 A top view of the reflective and supporting elements. Please refer to... Figure 1 and Figure 2 The backlight module 100 includes a reflective element 110, a plurality of light-emitting elements 120, and a light diffuser plate 130. The reflective element 110 has a first surface 111 and a second surface 112 (drawn on...). Figure 1 The system includes a first surface 111 and a second surface 112. Each light source slot 113 extends from the first surface 111 toward the second surface 112 and has a light outlet O located on the first surface 111. Multiple light-emitting elements 120 are respectively disposed within the light source slots 113. A light diffuser plate 130 is disposed opposite to the first surface 111, wherein the distance D between the light diffuser plate 130 and the first surface 111 is between 0.5 mm and 4 mm.

[0087] Figure 3 yes Figure 1 The diagram shows the light pattern distribution of the light-emitting element at horizontal and vertical viewing angles. Please refer to the following diagrams first. Figure 1 The light-emitting element 120 may include a light-emitting diode (LED). In one embodiment, the light-emitting element 120 may be an unpackaged light-emitting chip diced from a wafer, such as an LED chip. For example, the LED chip may be a grain-scale nitride LED chip that emits blue light at its main wavelength, but the invention is not limited thereto. Please refer to [further details omitted]. Figure 1 and Figure 3In this embodiment, the light-emitting element 120 may have a top surface 121 and a bottom surface 122. The top surface 121 is opposite to the bottom surface 122 and faces the light-emitting port O. The top surface 121 has a normal N. The angle between the peak angle of the light intensity emitted by each light-emitting element 120 and the normal N may be between -5 degrees and 5 degrees, and the beam angle BA of each light-emitting element 120 may be between 120 degrees and 140 degrees. Thus, the light beam L generated by the light-emitting element 120 can be emitted from the light-emitting port O at a smaller angle, and the brightness of the light beam L emitted from the light-emitting port O is more uniform, thereby improving the brightness contrast of the backlight module 100 when performing dimming in the execution area. In addition, using the light-emitting element 120 can also improve the light emission brightness of the backlight module 100 and reduce the cost of the backlight module 100. In one embodiment, the angle between the peak angle of the light-emitting element 120 at the horizontal viewing angle and the vertical viewing angle and the normal N may be approximately 0 degrees, but other embodiments are not limited to this. Incidentally, in one embodiment, the side 123 of the light-emitting element 120 may be surrounded by a frame (not shown) and shielded by the frame; furthermore, the frame may be made of a light-transmitting or opaque material, but other embodiments are not limited thereto. However, in another embodiment, the frame may be omitted to expose the side 123 of the light-emitting element 120.

[0088] Please continue to refer to this. Figure 1 The light diffuser 130 allows light L generated by the light-emitting element 120 to be incident upon it. In this embodiment, the light diffuser 130 may have a light-emitting surface 131 and a light-incident surface 132. The light-emitting surface 131 faces away from the first surface 111 and is opposite to the light-incident surface 132. Please refer to [further details]. Figure 1 and Figure 4 The light-emitting surface 131 and / or the light-incident surface 132 may have multiple optical microstructures 1310. In this way, the brightness of the light ray L emitted from the light-emitting surface 131 can be more uniform. For example, please refer to... Figure 6 and Figure 7Each optical microstructure 1310 may have a bevel 1311. The bevel 1311 stands on the light-emitting surface 131 and / or the light-incident surface 132, and in this embodiment, the bevel 1311 stands on the light-emitting surface 131, for example. The bevel 1311 is inclined relative to the light-emitting surface 131 and the light-incident surface 132. The two bevels 1311 of two adjacent optical microstructures 1310 in the optical microstructure face each other, and the two bevels 1311 are adjacent to each other by a connecting line 1312. An angle A' is between the two bevels 1311, and the angle A' is between 30 degrees and 150 degrees. The connecting lines 1312 of four adjacent optical microstructures 1310 in the optical microstructure intersect at the intersection point P, and eight adjacent optical microstructures 1310 in the optical microstructure are adjacent to each other around the intersection point P. In this way, the light emission uniformity of the light diffuser 130 can be further improved, thereby improving the optical quality of the backlight module 100. Furthermore, because the light diffuser 130 enables more uniform light emission, the distance between the light diffuser 130 and the light-emitting element 120 can be reduced, thereby reducing the thickness of the backlight module 100. On the other hand, because the light diffuser 130 enables more uniform light emission, the distance between the light-emitting elements 120 can be increased, thereby reducing the number of light-emitting elements 120, which can further reduce the cost of the backlight module 100.

[0089] It is understandable that the shape of the optical microstructure 1310 is not limited to... Figure 6 As shown. In other embodiments, the shape of the optical microstructure may include a triangular pyramid, a square pyramid, a triangular prism, a cylinder, a cone, or a sphere, respectively. For example, as... Figure 6 As shown, each optical microstructure 1310a may include a triangular pyramid Ta, and the triangular pyramids Ta may be arranged close together. Further, please refer to... Figure 7 The angle A1 of the apex of each triangular pyramid Ta can be between 30° and 150°, but other embodiments are not limited to this. In another embodiment, for example... Figure 8 As shown, each optical microstructure 1310b may include a square pyramid Q, and the square pyramids Q may be arranged close together. Furthermore, please refer to... Figure 9 Each optical microstructure 1310c may include a sphere, while Figure 9 Take a hemisphere HS as an example. Specifically, the radius of curvature of the spherical surface SS of the hemisphere HS can be between 0.002 mm and 0.05 mm, the radius R1 of the hemisphere HS can be between 5 μm and 500 μm, and the height H1 of the hemisphere HS can be between 10 μm and 200 μm. In another embodiment, for example... Figure 10As shown, each optical microstructure 1310d may include a cone C. Further, the radius of curvature of the curved surface CS of the cone C can be between 0.002 mm and 0.05 mm, the radius R2 of the base of the cone C can be between 5 μm and 500 μm, and the height H2 of the cone C can be between 10 μm and 200 μm. It is understood that this invention does not impose many restrictions on the shape and arrangement of the optical microstructures, nor does it impose many restrictions on the specific dimensions of the optical microstructures.

[0090] Please refer to this again. Figure 1 and Figure 2 In this embodiment, the light source slot 113 of the reflective element 110 may have a bottom 1131 and a reflective portion 1132. The bottom 1131 is opposite to the light outlet O and is adapted to accommodate the light-emitting element 120. The reflective portion 1132 is located between the light outlet O and the bottom 1131 and is adapted to surround the light-emitting element 120. Specifically, the reflective portion 1132 can reflect the light L generated by the light-emitting element 120. For example, the reflective element 110 in this embodiment may include a plurality of reflective sheets, and the reflective sheets may be connected to each other to form the reflective portion 1132. Furthermore, the material of the reflective sheets may include metal, but the present invention is not limited thereto. In one embodiment, the material of the reflective element 110 may include reflective adhesive, and the aforementioned reflective adhesive may be formed into the reflective element 110 by injection molding or hot pressing, and the reflective portion 1132 is formed together. In another embodiment, the reflective portion 1132 may be formed by a reflective layer disposed on the reflective element 110, and the present invention does not impose many restrictions on the materials and manufacturing processes of the reflective element 110 and the reflective portion 1132. Furthermore, the bottom 1131 of this embodiment can reflect light L to increase light utilization. The features of the bottom 1131 are similar to those of the reflective portion 1132, so related descriptions are omitted here.

[0091] Compared to existing technologies, the backlight module 100 employs a reflective element 110 and a light diffuser plate 130. The light L generated by the light-emitting element 120, after being reflected by the reflective element 110, can exit from the reflective element 110 at a relatively small exit angle. Furthermore, because the distance D between the light diffuser plate 130 and the first surface 111 of the reflective element 110 is between 1 mm and 4 mm, the light L exiting from the reflective element 110 will enter the light diffuser plate 130 at a relatively small angle, thereby reducing the exit angle of the light L from the light diffuser plate 130. Based on the above structure, the backlight module 100 of this embodiment has the advantages of a small exit angle and uniform light output brightness, thereby improving the brightness contrast of the dimming area performed by the backlight module 100.

[0092] It is worth mentioning that the backlight module 100 also includes, for example, a support element 140. The support element 140 is fixed to the reflective element 110 and abuts against the light diffuser plate 130, so that there is a distance D between the light diffuser plate 130 and the first surface 111. Simply put, one side of the support element 140 can be fixed to the reflective element 110, and the other side of the support element 140 can be used to place the light diffuser plate 130 to maintain the distance D between the light diffuser plate 130 and the first surface 111. In detail, the first surface 111 may have an outer edge OE, and the outer edge OE surrounds the light outlet O; for example, in this embodiment, the outer edge OE surrounds all the light outlets O. The support element 140 can be fixed to the reflective element 110 along the outer edge OE. For example, the support element 140 can be fixed to the outer surface OS of the reflective element 110 (drawn on the outer surface OS) along the outer edge OE. Figure 1 However, the present invention does not impose many restrictions on the fixed position of the support element 140. Furthermore, in this embodiment, the support element 140 extends continuously along the outer edge OE and is frame-shaped, but in another embodiment, the support element 140 may be segmented along the outer edge OE. In another embodiment, the support element 140 may be located at a corner of the outer edge OE, and the present invention does not impose many restrictions on the specific shape of the support element 140.

[0093] Incidentally, the support element 140 and the reflective element 110 can be integral or separate structures. For example, in this embodiment, the support element 140 and the reflective element 110 are separate structures, wherein the support element 140 can be fixed to the reflective element 110 by adhesive. In one embodiment, the support element 140 and the reflective element 110 are integral structures, and the support element 140 and the reflective element 110 can be formed together by injection molding or thermoforming. In another embodiment, the support element 140 and the reflective element 110 are integral structures, wherein the reflective element 110 can be formed first by injection molding or thermoforming, and the support element 140 is fixed to the reflective element 110 by a similar process. The material of the support element 140 in this embodiment may include rubber, but other embodiments are not limited thereto. For example, in one embodiment, the materials of the support element 140 and the reflective element 110 may include polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), or polyethylene (PE), etc., and the present invention does not impose further limitations on this. It should be noted that regardless of whether the support element 140 and the reflective element 110 are integral or separate structures, the support element 140 and the reflective element 110 may be made of different materials, and the present invention does not limit whether the materials of the support element 140 and the reflective element 110 are the same.

[0094] Please continue to refer to this. Figure 1The backlight module 100 in this embodiment also includes, for example, an optical film 150, which is disposed on the side of the light diffuser plate 130 opposite to the reflective element 110. Specifically, the optical film 150 may be disposed opposite to the light-emitting surface 131. There may be multiple optical films 150, which may include brightness enhancement films, beam-splitting films, and diffusion films. In one embodiment, the optical film 150 may also include a wavelength conversion film and a color filter film, but the present invention does not impose many limitations on the type and number of optical films 150.

[0095] Figure 11 This is a cross-sectional schematic diagram of a backlight module according to another embodiment of the present invention. The structure and advantages of the backlight module 100a in this embodiment are similar to those of the present invention. Figure 1 The following describes only the differences in the embodiments. Please refer to [the previous text]. Figure 11 The reflective portion 1132 of the light source slot 113a includes, for example, a first reflective surface RS1 and a second reflective surface RS2. The first reflective surface RS1 is located between the second reflective surface RS2 and the bottom 1131a, and the second reflective surface RS2 is located between the first reflective surface RS1 and the light exit port O. The slope S1 of the first reflective surface RS1 relative to the second surface 112a can be smaller than the slope S1 of the second reflective surface RS2 relative to the second surface 112a. In this way, the reflective element 110a can further reduce the angle at which the light L1 is emitted from the light exit port O, making the light emission angle of the backlight module 100a even smaller, thereby further improving the brightness contrast of the dimming area of ​​the backlight module 100a.

[0096] In this embodiment, the first reflecting surface RS1 and the second reflecting surface RS2 may each comprise a plane, and the second surface 112 of the reflecting element 110a is, for example, a plane. The first reflecting surface RS1 and the second reflecting surface RS2 may be inclined relative to the second surface 112. In one embodiment, the slope S1 of the first reflecting surface RS1 is, for example, between 0 and 1.5, which can further reduce the angle at which the light L1 exits from the light outlet O. In another embodiment, the slope S1 of the first reflecting surface RS1 may be 0. In other words, the first reflecting surface RS1 may be, for example, a plane substantially parallel to the second surface 112, and may be located at the bottom 1131a of the light source slot 113a, which can further increase the light utilization rate, thereby improving the light output brightness of the reflecting element 110a. Furthermore, in another embodiment, the second reflecting surface RS2 may be adjacent to the light outlet O, and the second reflecting surface RS2 may be perpendicular to the second surface 112. In other words, the slope S2 of the second reflecting surface RS2 may be close to infinity, so as to be substantially perpendicular to the second surface 112. It is understood that although the reflective portion 1132 in this embodiment is exemplified by two reflective surfaces, namely the first reflective surface RS1 and the second reflective surface RS2, the present invention does not impose many limitations on the number of reflective surfaces. For example, in one embodiment, the reflective portion 1132 may include three or more reflective surfaces, and the slope of each reflective surface relative to the second surface 112 may gradually increase from the side of the light source slot 113a near the bottom 1131a toward the light outlet O. In another embodiment, the reflective portion 1132 may include three or more reflective surfaces, and the slope of each reflective surface relative to the second surface 112 may be alternately large and small in the direction from the bottom 1131a of the light source slot 113a toward the light outlet O. Incidentally, the bottom 1131a in this embodiment may be open, and the light-emitting element 120 may be disposed in the opening, but the present invention does not impose many limitations on the specific features of the bottom 1131a.

[0097] It is worth mentioning that, in this embodiment, the two adjacent light-emitting ports O can have a spacing G between them on the first surface 111, and the spacing G can be between 0.01mm and 2mm. Specifically, the spacing G can better prevent the light L2 emitted from one of the light-emitting ports O from passing over the other adjacent light-emitting port O. Thus, when the backlight module 100a performs regional dimming, the reflective element 110a can further reduce the interference of light emitted from the bright area to the dark area, thereby further improving the brightness contrast of the backlight module 100a when performing regional dimming. In this embodiment, the portion of the first surface 111 located between the two adjacent light-emitting ports O is, for example, a plane FS, and the plane FS can be sandwiched with a sharp angle TA between it and the two adjacent reflective portions 1132 (for example, two adjacent first reflective surfaces RS1). In detail, the two sharp corners TA can block more light rays (e.g., light ray L2) that are about to exit from the light outlet O at a larger angle, thus reducing the angle at which the light rays exit from the light outlet O, and further improving the brightness contrast of the backlight module 100a when dimming the execution area. However, in one embodiment, the portion of the first surface 111 located between two adjacent light outlets O is, for example, a curved surface; specifically, because the curved surface can reflect light more uniformly, the brightness of the light emitted by the reflective element 110a can be more uniform, and it also has the advantage of being easy to manufacture. The radius of curvature of the curved surface is, for example, between 0.01 mm and 2 mm, but the present invention does not impose any restrictions on this. Incidentally, the curved surface is, for example, formed by polishing a flat surface FS, but the present invention does not impose any restrictions on the manufacturing method.

[0098] Figure 12 yes Figure 11 A schematic diagram of the light pattern distribution of the light-emitting element. Please refer to it as well. Figure 11 and Figure 12 In this embodiment, the angle A between the peak angle of the light emission intensity of the light-emitting element 120 and the normal N is, for example, between 50 and 90 degrees. In one embodiment, the angle A may be between approximately 70 and 90 degrees, and for example, approximately 80 degrees. Thus, the light L1 generated by the light-emitting element 120, after being reflected by the first reflecting surface RS1 and the second reflecting surface RS2, can be emitted from the light emission port O at a smaller angle, thereby further improving the brightness contrast of the backlight module 100a when performing dimming in the execution area. In another embodiment, such as... Figure 13 As shown, the included angle A can be between 50 degrees and 70 degrees to further improve the brightness contrast of the backlight module 100a when dimming the execution area. Please refer to [link / reference needed]. Figure 11 In this embodiment, the beam angle BA1 of each light-emitting element 120 is, for example, between 140 degrees and 180 degrees. This further improves the brightness contrast of the backlight module 100a when performing dimming in the execution area.

[0099] Incidentally, the backlight module 100a of this embodiment may also include a plurality of light-shielding elements 160, each light-shielding element 160 being disposed on the top surface 121 of each light-emitting element 120, such that the included angle A may be approximately between 50 and 90 degrees. For example, the light-shielding element 160 may include a light-shielding cover or a distributed Bragg reflector (DBR), but other embodiments are not limited thereto.

[0100] Figure 14 This is a cross-sectional schematic diagram of a backlight module according to another embodiment of the present invention. The structure and advantages of the backlight module 100b in this embodiment are similar to those of the present invention. Figure 11 The following describes only the differences in the embodiments. Please refer to... Figure 14 The curvature C1 of the first reflecting surface RS1b can be greater than the curvature C2 of the second reflecting surface RS2b. For example, in one embodiment, the curvature C2 of the second reflecting surface RS2b can be close to zero; in other words, the second reflecting surface RS2b can be substantially perpendicular to the second surface 112b of the reflecting element 110b. Similarly, in addition to the first reflecting surface RS1b and the second reflecting surface RS2b, the reflecting portion 1132b can also have more reflecting surfaces. For example, in one embodiment, the reflecting portion 1132b can have more than two reflecting surfaces, and the curvature of each reflecting surface can gradually decrease from the side of the light source slot 113b near the bottom 1131b towards the light outlet O. Similarly, in this embodiment, the peak angle of the light emission intensity of the light-emitting element 120 can be approximately between 50 and 90 degrees, and the peak angle of the light-emitting element 120 can be approximately within the above range by the light-shielding element 160. However, the present invention does not impose many restrictions on the means of changing the peak angle of the light-emitting element 120.

[0101] In summary, the backlight module of the present invention employs a reflective element and a light diffuser plate. Light generated by the light-emitting element is reflected by the reflective element and emitted from it at a relatively small emission angle. Furthermore, because the distance between the light diffuser plate and the first surface of the reflective element is between 1 mm and 4 mm, light emitted from the reflective element enters the light diffuser plate at a smaller angle, thus reducing the angle at which light exits the light diffuser plate. Based on this structure, the backlight module of the present invention has the advantages of a small emission angle and uniform emission brightness, thereby improving the brightness contrast of the dimming area of ​​the backlight module.

[0102] Although the present invention has been disclosed above by way of embodiments, it is not intended to limit the present invention. Those skilled in the art to which this invention pertains may make some modifications and refinements without departing from the spirit and scope of the present invention. Therefore, the scope of protection of the present invention shall be determined by the appended claims.

Claims

1. A backlight module, characterized in that, include: A reflective element has a first surface, a second surface, and a plurality of light source slots, the first surface and the second surface being opposite to each other, the light source slots extending from the first surface toward the second surface, and each having a light outlet located on the first surface; Multiple light-emitting elements are respectively disposed in the light source slots; and A light diffusion plate is disposed opposite to the first surface, wherein the distance between the light diffusion plate and the first surface is between 0.5 mm and 4 mm; The light diffuser has a light-emitting surface and a light-receiving surface. The light-emitting surface faces away from the first surface and is opposite to the light-receiving surface. The light-emitting surface and / or the light-receiving surface has a plurality of optical microstructures. Each of the optical microstructures has an inclined surface that stands on the light-emitting surface and / or the light-receiving surface and is inclined relative to the light-emitting surface and the light-receiving surface. The two inclined surfaces of two adjacent optical microstructures face each other and are adjacent to each other by a connecting line. The two inclined surfaces are separated by an angle between 30 degrees and 150 degrees. The connecting lines of four adjacent optical microstructures intersect at an intersection point, and eight adjacent optical microstructures are adjacent to each other around the intersection point.

2. The backlight module as described in claim 1, characterized in that, It further includes a support element, wherein the support element is fixed to the reflective element and abuts against the light diffusion plate, so that there is the distance between the light diffusion plate and the first surface.

3. The backlight module as described in claim 2, characterized in that, The first surface has an outer edge surrounding the light outlets, and the support element is fixed to the reflective element along the outer edge.

4. The backlight module as described in claim 2, characterized in that, The support element and the reflective element can be integrated or separate.

5. The backlight module as described in claim 4, characterized in that, The materials of the support element and the reflective element include rubber, polycarbonate, polypropylene, polyethylene terephthalate, or polyethylene.

6. The backlight module as described in claim 1, characterized in that, Each of the light source slots has a bottom and a reflective portion. The bottoms are respectively opposite to the light outlets and are adapted to accommodate the light-emitting elements. The reflective portion is located between the light outlet and the bottom and is adapted to surround the light-emitting element. The reflective portion includes a first reflective surface and a second reflective surface. The first reflective surface is located between the second reflective surface and the bottom, and the second reflective surface is located between the first reflective surface and the light outlet. The slope of the first reflective surface relative to the second surface is less than the slope of the second reflective surface relative to the second surface, or the curvature of the first reflective surface is greater than the curvature of the second reflective surface.

7. The backlight module as described in claim 1, characterized in that, Each of the light-emitting elements has a top surface and a bottom surface, the top surfaces are opposite to the bottom surfaces and face the light-emitting ports, the top surfaces have a normal, the peak angle of the light intensity of each of the light-emitting elements is between 50 degrees and 90 degrees with the normal, and the beam angle of the light-emitting elements is between 140 degrees and 180 degrees.

8. The backlight module as described in claim 7, characterized in that, It also includes multiple light-shielding elements, wherein the light-emitting element has a top surface and a bottom surface, the top surface and the bottom surface are opposite to each other, and the top surface faces the light outlet, and the light-shielding elements are respectively disposed on the top surface.

9. The backlight module as described in claim 1, characterized in that, Each of the light-emitting elements has a top surface and a bottom surface, the top surfaces are opposite to the bottom surfaces and face the light-emitting ports, the top surfaces have a normal, the peak angle of the light intensity of each of the light-emitting elements is between -5 degrees and 5 degrees with the normal, and the beam angle of each of the light-emitting elements is between 120 degrees and 140 degrees.

10. The backlight module as described in claim 1, characterized in that, The first surface has a spacing between two adjacent light-emitting ports, which is between 0.01 mm and 2 mm.

11. The backlight module as described in claim 1, characterized in that, The shapes of these optical microstructures include triangular pyramids, quadrangular pyramids, triangular prisms, cylinders, cones, or spheres.

12. The backlight module as described in claim 1, characterized in that, It also includes an optical film disposed on the side of the light diffuser opposite the reflective element.

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