Backlight module

Abstract

The backlight module disclosed by the present invention comprises a substrate, a plurality of lamp beads mounted on the substrate, a diffusion sheet arranged above the plurality of lamp beads and used for diffusing light, and a reflection part used for reflecting light, wherein the diffusion sheet has a light-transmitting area and a plurality of light-reflecting areas distributed in the light-transmitting area, each light-reflecting area comprises a plurality of light-reflecting circles formed by a reflective material, the light-reflecting area reflects the light emitted by the lamp beads irradiated thereon to the reflection part, the distance between the light-reflecting circles close to the lamp beads in the light-reflecting area is smaller than the distance between the light-reflecting circles far from the lamp beads, or the width of the light-reflecting circles close to the lamp beads is larger than the width of the light-reflecting circles far from the lamp beads, so that the light transmission effect of high light intensity close to the lamp beads is poor, the light transmission effect of low light intensity far from the lamp beads is good, and the light diffusion effect is poor, so that the surface light source can emit light uniformly, the light utilization efficiency is improved, the visual realism effect is achieved, and the effects of higher dynamic range and contrast are achieved.

Description

Technical Field

[0001] The invention relates to a backlight module, belonging to the technical field of display. Background Art

[0002] Mini LED is an LED chip with a size of about 100um, which is between LED and OLED. Compared with side backlight LED, mini LED has better high dynamic range, better contrast and width range, and meets the user's thinner needs and faster response speed; compared with OLED, mini LED is cheaper and has a longer life structure. However, mini LED uses direct backlight, which will cause bright and dark fields in various parts of the picture, resulting in poor visual effects and affecting the user experience. Summary of the invention

[0003] The object of the present invention is to provide a backlight module with uniform light output from a surface light source and high light utilization efficiency.

[0004] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a backlight module, comprising a substrate, and a plurality of lamp beads installed on the substrate, the backlight module also comprising a diffuser arranged above the plurality of lamp beads and used to diffuse light, and a reflective portion for reflecting light, the diffuser having a light-transmitting area and a plurality of reflective areas distributed in the light-transmitting area, each of the reflective areas comprising a plurality of reflective circles formed by reflective material, the reflective area reflects the light emitted by the lamp beads irradiated thereon to the reflective portion, the distance between the reflective circles in the reflective area close to the lamp beads is smaller than the distance between the reflective circles far from the lamp beads, or the width of the reflective circles close to the lamp beads is greater than the width of the reflective circles far from the lamp beads.

[0005] Furthermore, the plurality of reflective circles in the reflective area are connected end to end.

[0006] Furthermore, the centers of the multiple reflective circles in the reflective area are the same.

[0007] Furthermore, the reflective ring is circular.

[0008] Furthermore, the cross section of the reflective ring is a triangle.

[0009] Furthermore, the diffusion sheet has an upper surface away from the substrate, and the reflective ring is formed on the upper surface.

[0010] Furthermore, the lamp bead is a mini LED lamp.

[0011] Furthermore, the width of the reflective ring is 2 to 5 um, and the height of the cross section is 4 to 10 um.

[0012] Furthermore, the reflecting part comprises a reflecting sheet arranged between the diffusion sheet and the substrate, and the reflecting sheet is provided with openings corresponding to the lamp beads.

[0013] Furthermore, the reflective material is one or a combination of reflective ink, metallic silver, and metallic aluminum.

[0014] The beneficial effects of the present invention are as follows: the present invention provides a light-transmitting area and a plurality of reflective areas distributed in the light-transmitting area on a diffuser, and provides a reflective portion on a substrate, so that the reflective area reflects light irradiated thereon to the reflective portion, each reflective area includes a plurality of reflective circles formed by reflective material, and the distance between the reflective circles in the reflective area close to the lamp beads is smaller than the distance between the reflective circles far away from the lamp beads, or the width of the reflective circles close to the lamp beads is larger than the width of the reflective circles far away from the lamp beads, so that the light transmission effect of high light intensity near the lamp beads is poor, the light transmission effect of low light intensity far away from the lamp beads is good, and the light diffusion effect is poor, thereby achieving uniform light output from the surface light source, improving the utilization efficiency of light, achieving the effect of visual realism, and the effects of higher dynamic range and contrast.

[0015] The above description is only an overview of the technical solution of the present invention. In order to more clearly understand the technical means of the present invention and implement it according to the contents of the specification, the following is a detailed description of the preferred embodiments of the present invention in conjunction with the accompanying drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 is a schematic structural diagram of a backlight module shown in an embodiment of the present invention;

[0017] Figure 2 A schematic diagram of a reflective area with a spiral reflective ring according to an embodiment of the present invention;

[0018] Figure 3 A schematic diagram of another reflective area with a spiral reflective ring according to an embodiment of the present invention;

[0019] Figure 4 A schematic diagram of a reflective area having the same central reflective circle according to an embodiment of the present invention;

[0020] Figure 5 is a cross-sectional view of a reflective ring shown in an embodiment of the present invention;

[0021] Figure 6 FIG. 4 is a cross-sectional view of another reflective ring according to an embodiment of the present invention. DETAILED DESCRIPTION

[0022] The technical solution of the present invention will be described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0023] In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the mechanism or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only, and cannot be understood as indicating or implying relative importance.

[0024] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0025] In addition, the technical features involved in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other.

[0026] See also Figure 1 The backlight module shown in an embodiment of the present invention is specifically a direct-type backlight module, including a substrate 1, a plurality of lamp beads 2 installed on the substrate 1, a diffuser 4 arranged above the plurality of lamp beads 2 and used to diffuse light, and a reflective portion located between the substrate 1 and the diffuser 4 and used to reflect light.

[0027] In this embodiment, the lamp bead 2 is a mini LED lamp. Since the mini LED lamp has a small chip structure, it is beneficial to make the number of dimming zones (Local Dimming Zones) more detailed, thereby achieving a higher dynamic range (HDR) and a higher contrast effect; on the other hand, the use of mini LED lamps can also shorten the optical mixing distance (OD) to reduce the thickness of the backlight module to achieve the purpose of ultra-thinness. Of course, in other embodiments, the lamp bead 2 can also be LED, OLED, etc., which is not specifically limited here and can be selected according to actual needs. In this embodiment, a plurality of mini LED lamp arrays are arranged on a substrate 1. The spacing between adjacent mini LED lamps, the specific number of mini LED lamps, and the arrangement of the mini LED lamps on the substrate 1 are not specifically limited here and can be selected according to actual needs.

[0028] The reflective part includes a reflective sheet 3 arranged between the diffuser 4 and the substrate 1, and an opening 31 corresponding to the lamp bead 2 is opened on the reflective sheet 3, and each lamp bead 2 passes through the corresponding opening 31 and emerges from the opening 31. The reflective sheet 3 is made of a transparent or semi-transparent material coated with a layer of reflective material. The transparent or semi-transparent material is one of glass, acrylic resin, polycarbonate, amorphous polyolefin and polyester, but not limited to this, and is not listed here one by one. The reflective material can be one of reflective ink, metallic silver, and metallic aluminum, but not limited to this, and can also be other reflective materials, or a mixture of multiple reflective materials. The function of the reflective sheet 3 is to reflect light, and the light reflected by the reflective sheet 3 is then reflected onto the diffuser 4, making full use of light energy and improving the uniformity of the overall light. In addition, the reflective part also includes a reflective layer (not shown) formed on the substrate 1, and the reflective layer is formed by coating the reflective material on the substrate 1. In this embodiment, the reflective material is coated on the side of the substrate 1 where the lamp beads 2 are installed, so as to reflect the light reflected by the diffuser 4 and irradiated onto the substrate 1, and further improve the uniformity of the overall light. Of course, in other embodiments, the reflective part may not include the reflective sheet 3, or the reflective part may not include a reflective layer formed on the substrate 1.

[0029] The diffuser 4 has a light-transmitting area 42 and a plurality of reflective areas 41 distributed in the light-transmitting area 42. Each reflective area 41 is arranged corresponding to a lamp bead 2. Each reflective area 41 includes a plurality of reflective circles 411 formed by reflective materials. The area between the reflective circles 411 is the light-transmitting area 42. In the present embodiment, the diffuser 4 is made of a transparent material or a translucent material, and has a thickness of 0.5-1 mm. The thickness of the diffuser 4 is not specifically limited here, and can be prepared according to actual needs. Transparency is an inherent property of the diffuser 4. Therefore, before the reflective area 41 is formed on the surface of the diffuser 4, the diffuser 4 only has the light-transmitting area 42. Of course, in other embodiments, the diffuser 4 can also be made of a reflective material. Therefore, the diffuser 4 only has the reflective area 41, and the light-transmitting area 42 can be photoetched on the surface of the diffuser 4.

[0030] The diffuser 4 has an upper surface away from the substrate 1 and a lower surface arranged relative to the upper surface. In this embodiment, a reflective circle 411 is formed on the upper surface. A concave portion is formed on the upper surface of the diffuser 4. The concave portion is formed inwardly from the upper surface of the diffuser 4. The width of the concave portion is 2 to 5 um, and the height of the cross section is 4 to 10 um. The specific size of the concave portion is not specifically limited here. The specific shape of the concave portion on the surface of the diffuser 4 is a circle, and the cross section of the concave portion is a triangle, or a rectangle. The reflective circle 411 can be formed by coating the reflective material in the concave portion of the diffuser 4. Similarly, the reflective material is one of reflective ink, metallic silver, and metallic aluminum, but is not limited thereto. It can also be other reflective materials, or a mixture of multiple reflective materials. It should be noted here that the reflective material formed by mixing reflective ink with metallic silver or metallic aluminum is an existing material.

[0031] The reflective area 41 reflects the light emitted by the lamp bead 2 that is irradiated thereon to the reflective portion. Specifically, the light emitted by the lamp bead 2 is irradiated onto the diffuser 4, a portion of the light is irradiated onto the light-transmitting area 42 and directly passes through the diffuser 4 to be emitted, and a portion of the light irradiated onto the reflective ring 411 is partially reflected by the reflective ring 411 to the reflective sheet 3, and the light is then reflected by the reflective sheet 3 to the diffuser 4, and directly passes through the diffuser 4 to be emitted or continues to be repeatedly reflected according to different positions on the diffuser 4, so that the lamp bead 2 irradiates diffused and uniform light through the diffuser 4.

[0032] In the present embodiment, the lamp bead 2 is a rectangular structure, and the light at the position close to the lamp bead 2 on the diffuser 4 is relatively strong, and the light at the position far away from the lamp bead 2 is relatively weak. Therefore, in order to be able to convert the light emitted by the lamp bead 2 into uniform light, the shape of the reflective area 41 formed on the diffuser 4 is set according to the lamp bead 2, and the distance between the reflective circles 411 close to the lamp bead 2 in the reflective area 41 is smaller than the distance between the reflective circles 411 far away from the lamp bead 2, or the width of the reflective circle 411 close to the lamp bead 2 is larger than the width of the reflective circle 411 far away from the lamp bead 2, so that when the high-intensity light close to the lamp bead 2 passes through the diffuser 4, the light transmission effect is poor and the light diffusion effect is good; when the low-intensity light far away from the lamp bead 2 passes through the diffuser 4, the light transmission effect is good and the light diffusion effect is poor, thereby achieving uniform light output on the surface of the diffuser 4 and eliminating the uneven brightness between the lamp beads 2.

[0033] See also Figure 2 and Figure 3 , the structure of a reflective area 41 on the diffuser 4 can be a spiral formed by connecting multiple reflective circles 411 end to end, and the area between the reflective circles 411 is the light-transmitting area 42 on the diffuser 4, and the center position of the reflective area 41 corresponds to the center position of a lamp bead 2. Since the lamp bead 2 in this embodiment is a rectangular structure, the shape of the spiral reflective circle 411 is similar to an ellipse. The specific shape of the reflective area 41 can be designed according to the actual structure of the lamp bead 2 and the intensity curve of the light of the lamp bead 2. In this embodiment, the width of the spiral reflective circle 411 remains the same, such as Figure 3 As shown, however, the distance between the reflective circles 411 close to the lamp bead 2 is smaller than the distance between the reflective circles 411 far from the lamp bead 2, so that the distribution density of the reflective circles 411 close to the lamp bead 2 is greater than the distribution density of the reflective circles 411 far from the lamp bead 2. The spiral reflective circles 411 can also be designed so that the width of the reflective circles 411 close to the lamp bead 2 is greater than the width of the reflective circles 411 far from the lamp bead 2, and at the same time, the distances between the reflective circles 411 are the same, so that the reflective area 41 formed by the reflective circles 411 close to the lamp bead 2 is greater than the reflective area 41 formed by the reflective circles 411 far from the lamp bead 2. In addition, the spiral reflective circles 411 can also be designed so that the width of the reflective circles 411 close to the lamp bead 2 is greater than the width of the reflective circles 411 far from the lamp bead 2, and at the same time, the distance between the reflective circles 411 close to the lamp bead 2 is smaller than the distance between the reflective circles 411 far from the lamp bead 2, as shown in FIG. Figure 2 As shown, the distribution density of the reflective circles 411 close to the lamp beads 2 is greater than the distribution density of the reflective circles 411 far from the lamp beads 2.

[0034] See also Figure 4, the centers of multiple reflective circles 411 of a reflective area 41 on the diffuser are the same, that is, the reflective area 41 is composed of multiple reflective circles 411 with the same center, and the reflective circles 411 are circular or elliptical. Similarly, the area between the reflective circles 411 is the light-transmitting area 42 on the diffuser 4, the center position of the reflective area 41 corresponds to the center position of a lamp bead 2, and the reflective circle 411 is elliptical. Figure 3 , the distance between the reflective circles 411 close to the lamp beads 2 in the reflective area 41 is smaller than the distance between the reflective circles 411 far from the lamp beads 2, so that the distribution density of the reflective circles 411 close to the lamp beads 2 is greater than the distribution density of the reflective circles 411 far from the lamp beads 2, or refer to Figure 4 The width of the reflective circle 411 close to the lamp bead 2 is greater than the width of the reflective circle 411 far from the lamp bead 2, so that when the high-intensity light close to the lamp bead 2 passes through the diffuser 4, the amount of light transmitted is small and the amount of light reflected is large, while, when the low-intensity light far from the lamp bead 2 passes through the diffuser 4, the amount of light transmitted is large and the amount of light reflected is small, so that the light energy on the surface of the diffuser 4 is evenly distributed. In addition, if the lamp bead 2 is a square structure, the shape of the reflective circle 411 can be circular or square.

[0035] Figure 5 This is a cross-sectional view of a reflective ring shown in an embodiment of the present invention. The width of the reflective ring 411 remains the same, but the distance between the reflective rings 411 close to the lamp beads (i.e., the center position) is smaller than the distance between the reflective rings 411 far from the lamp beads. Figure 6 This is a cross-sectional view of another reflective ring shown in an embodiment of the present invention. The width of the reflective ring 411 close to the lamp bead (i.e., the center position) is greater than the width of the reflective ring 411 away from the lamp bead. The cross-section of the concave portion on the surface of the diffuser 4 is designed to be a triangle, which is a right-angled triangle. At the same time, the vertex angle of the diffuser 4 is in the range of 20°-60°, so as to improve the diffusion intensity of the light on the diffuser 4. For details, please refer to Figure 1 and Figure 5 or Figure 1 and Figure 6 The light emitted by the lamp bead 2 located below the diffuser 4 passes through the lower surface of the diffuser 4 and enters the interior of the diffuser 4. A portion of the light is irradiated onto the light-transmitting area 42 on the upper surface of the diffuser 4 and directly passes through the diffuser 4 and is emitted out, while another portion of the light is irradiated onto one of the two side edges of the reflective ring 411 located inside the diffuser 4 and is partially reflected onto the reflective sheet 3, and the light is then reflected onto the diffuser 4 by the reflective sheet 3.

[0036] In summary, the present invention provides a light-transmitting area and a plurality of reflective areas distributed in the light-transmitting area on the diffuser, and provides a reflective portion on the substrate, so that the reflective area reflects light irradiated thereon to the reflective portion, each reflective area includes a plurality of reflective circles formed by reflective material, and the distance between the reflective circles in the reflective area close to the lamp beads is smaller than the distance between the reflective circles far away from the lamp beads, or the width of the reflective circles close to the lamp beads is larger than the width of the reflective circles far away from the lamp beads, so that the transmission effect of high-intensity light near the lamp beads is poor, the transmission effect of low-intensity light far away from the lamp beads is good, and the light diffusion effect is poor, thereby achieving uniform light output from the surface light source, improving the utilization efficiency of light, achieving the effect of visual realism, and the effects of higher dynamic range and contrast.

[0037] The technical features of the above-described embodiments may be arbitrarily combined. To make the description concise, not all possible combinations of the technical features in the above-described embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0038] The above-mentioned embodiments only express several implementation methods of the present invention, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the invention patent. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, and these all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A backlight module, comprising a substrate and a plurality of lamp beads mounted on the substrate, It is characterized in that The backlight module also includes a diffuser arranged above the plurality of lamp beads and used for diffusing light and a reflective portion for reflecting light, the diffuser having a light-transmitting area and a plurality of reflective areas distributed in the light-transmitting area, each of the reflective areas including a plurality of reflective circles formed by reflective material, the reflective area reflects the light emitted by the lamp beads irradiated thereon to the reflective portion, the distance between the reflective circles in the reflective area close to the lamp beads is smaller than the distance between the reflective circles away from the lamp beads, or the width of the reflective circles close to the lamp beads is larger than the width of the reflective circles away from the lamp beads, a concave portion is formed on the upper surface of the diffuser which is concave inward from the upper surface of the diffuser, reflective material is coated in the concave portion of the diffuser to form the reflective circle, the cross-section of the reflective circle is a triangle, and the vertex angle of the triangle ranges from any value of 20° to 60°.

2. The backlight module according to claim 1, It is characterized in that The multiple reflective circles in the reflective area are connected end to end.

3. The backlight module according to claim 1, It is characterized in that The centers of the multiple reflective circles in the reflective area are the same.

4. The backlight module according to claim 3, It is characterized in that The reflecting circle is circular.

5. The backlight module according to claim 1, It is characterized in that The diffusion sheet has an upper surface away from the substrate, and the reflective ring is formed on the upper surface.

6. The backlight module according to claim 1, It is characterized in that The lamp beads are miniLED lamps.

7. The backlight module according to claim 1, It is characterized in that The width of the reflective ring is 2-5um, and the height of the cross section is 4-10um.

8. The backlight module according to claim 1, It is characterized in that The reflecting part comprises a reflecting sheet arranged between the diffusion sheet and the substrate, and the reflecting sheet is provided with openings corresponding to the arrangement of the lamp beads.

9. The backlight module according to claim 1, It is characterized in that The reflective material is one or a combination of reflective ink, metallic silver, and metallic aluminum.

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