Quantum dot light diffusing plate and method for manufacturing the same

Abstract

The present invention discloses a quantum dot light diffusing plate and a manufacturing method thereof. The diffusing plate can be assembled on a backlight module with a blue light-emitting diode (LED) as a bottom light source. A plurality of microstructures having a plurality of concave portions and convex portions are formed on the surface of the diffusing plate, and a quantum dot layer including a plurality of green quantum dots and a plurality of red quantum dots is coated in the plurality of concave portions of the plurality of microstructures, and then a water and oxygen barrier layer is provided on the upper surface of the quantum dot layer. The plurality of convex portions of the plurality of microstructures are used to separate the quantum dot layers located in the plurality of concave portions so that they are independent of each other, so that moisture and oxygen in the outside world cannot invade the entire quantum dot layer through the four side end faces of the quantum dot layer, and it has the advantages of simple process, low cost and high production qualification rate.

Description

Technical Field

[0001] The present invention relates to a quantum dot light diffusing plate and a manufacturing method thereof, and particularly to a quantum dot light diffusing plate that can be assembled into a backlight module and can prevent the quantum dot layer on the light diffusing plate from reducing its activity due to the intrusion of water vapor and oxygen, and a manufacturing method thereof. Background Art

[0002] In the development of the backlight display environment, there are mainly two types of light emitting diodes (LEDs) used in traditional backlight displays. One is a blue LED that excites a yellow phosphor, and the two colors are mixed into white light; the other is a mixture of three primary color LEDs into white light. However, the color gamut values of the existing backlight displays using these two light sources are relatively low, and the color performance is insufficient.

[0003] Currently, the light source of the backlight display is a blue LED that excites green and red quantum dots, and the three lights are mixed into white light, which can increase the color gamut value to NTSC 120%. However, such a backlight display still has the following disadvantages. First, quantum dots are easily affected by water vapor and oxygen, resulting in a decrease or even loss of activity. After long-term use, quantum dot failure occurs, leading to color abnormality problems in the display. Second, a blue LED excites green and red quantum dots, and the blue, green, and red lights are mixed into white light. There must be a consistent light intensity to avoid insufficient red / green light conversion. However, due to the lower light intensity around the display than in the center, a blue light leakage phenomenon occurs around the display, resulting in inconsistent colors. Moreover, most of the existing quantum dot films use a method of attaching a water and oxygen barrier film on the surface to block water vapor and oxygen. However, this method can only block the water vapor and oxygen entering the quantum dot film from the upper surface and cannot prevent the water vapor and oxygen entering from the side end faces of the quantum dot film. Therefore, after a period of use, the four side edges of the quantum dot film of the backlight display will still be invaded by water vapor and oxygen, causing quantum dot failure and resulting in color abnormality in the peripheral area of the backlight display. Although some manufacturers have tried to coat a protective coating on the four side end faces of the quantum dot film of the backlight display, this method requires multiple processing steps, with complex processes, high costs, and low qualification rates.

[0004] Therefore, the present invention provides a quantum dot light diffusing plate and a manufacturing method thereof, which can be assembled into a backlight module and can prevent the quantum dot layer on the light diffusing plate from reducing its activity due to the intrusion of water vapor and oxygen, thus solving the various deficiencies of the aforementioned existing backlight displays. Summary of the Invention

[0005] The main object of the present invention is to provide a diffusion plate, which can be assembled on a backlight module using blue light-emitting diodes (LEDs) as a light source. A plurality of microstructures having a plurality of concave portions and convex portions are formed on the surface of the diffusion plate, and a quantum dot layer including a plurality of green quantum dots and a plurality of red quantum dots is coated in the plurality of concave portions of the plurality of microstructures, and then a water and oxygen barrier layer is disposed on the upper surface of the quantum dot layer. The plurality of convex portions of the plurality of microstructures are used to separate the quantum dot layers located in the plurality of concave portions so that they are independent of each other, so that water vapor and oxygen in the outside world cannot penetrate through the four side edges of the quantum dot layer to invade the entire quantum dot layer, which has the advantages of simple manufacturing process, low cost, and high production qualification rate, etc.

[0006] To achieve the above object, the present invention provides a quantum dot light diffusion plate, which can be combined onto a backlight module. The backlight module includes: a substrate and a plurality of blue light-emitting elements arranged in an array on the substrate. The diffusion plate is located above the substrate and includes: a plate body, a plurality of microstructures, a quantum dot layer, and a water and oxygen barrier layer. The plate body has an upper surface and a lower surface, and the lower surface faces the substrate. A plurality of microstructures are arranged in an array on the upper surface of the plate body; a plurality of the microstructures form a plurality of convex portions and a plurality of concave portions on the upper surface of the plate body, and the plurality of concave portions are separated by the plurality of convex portions, so that the plurality of concave portions are independent of each other and do not communicate with each other. The quantum dot layer is disposed at the plurality of concave portions on the upper surface of the plate body; wherein, the thickness of the quantum dot layer is t1, and the distance from the top of a plurality of the convex portions to the bottom of a plurality of the concave portions is t2, and, t1 < t2. The water and oxygen barrier layer is disposed on the upper surface of the plate body and covers the plurality of convex portions and the quantum dot layer.

[0007] In an embodiment, a plurality of the microstructures, the quantum dot layer, and the water and oxygen barrier layer are also disposed on the lower surface of the plate body; a plurality of the microstructures form a plurality of the convex portions and a plurality of the concave portions on the lower surface of the plate body, and the plurality of concave portions are separated by the plurality of convex portions, so that the plurality of concave portions on the lower surface of the plate body are independent of each other and do not communicate with each other; and, the quantum dot layer located on the lower surface of the plate body is disposed at the plurality of concave portions on the lower surface of the plate body; in addition, the water and oxygen barrier layer on the lower surface of the plate body covers the plurality of convex portions and the quantum dot layer on the lower surface of the plate body.

[0008] In one embodiment, the quantum dot layer contains a plurality of quantum dots (abbreviated as QD); the plurality of quantum dots are a kind of nanocrystal semiconductor material composed of elements of Group II-VI, III-V or IV-VI, and the grain diameter of each quantum dot is between 2 and 10 nm; wherein, the plurality of quantum dots include a plurality of green quantum dots with a light emission wavelength of 520-530 nm and a plurality of red quantum dots with a light emission wavelength of 620-630 nm.

[0009] In one embodiment, the plurality of microstructures include a plurality of N-sided pyramids, where N is a positive integer greater than or equal to three; t2 is between 6 and 200 μm; the thickness of the water and gas barrier layer is t3, and t3 is between 5 and 100 μm.

[0010] In one embodiment, t2 is between 25 and 50 μm, t1 is between 10 and 40 μm, and t3 is between 10 and 30 μm.

[0011] In one embodiment, the maximum width of the convex portion is between 50 and 500 μm, and the distance between adjacent convex portions is between 50 and 1000 μm.

[0012] In one embodiment, the material of the plate body includes one of the following: polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA, commonly known as acrylic), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET).

[0013] In one embodiment, the plate body is formed by foam extrusion, and the plate body contains a plurality of microbubbles; the weight reduction rate of the plurality of microbubbles for the plate body is between 15 and 25%, and the average size of the plurality of microbubbles is between 60 and 800 μm;

[0014] Among them, the calculation formula of the weight reduction rate is:

[0015] Weight reduction rate (%) = (W1 - W2) / W2 * 100%;

[0016] W1 = H * (L1 * L2 * D);

[0017] Among them:

[0018] H is the average thickness (mm) of the plate body;

[0019] L1 is the length (mm) of the plate body;

[0020] L2 is the width (mm) of the plate body;

[0021] D is the raw material specific gravity (g / mm 3 )

[0022] W1 is the theoretical weight (g) of the plate body, that is, the weight without a plurality of the microbubbles;

[0023] W2 is the actual weight (g) of the plate body, that is, the actual weight of the plate body containing a plurality of the microbubbles actually measured by a weighing scale.

[0024] In one embodiment, a plurality of the microbubbles are generated by adding a foaming agent and a nucleating agent in the foaming extrusion molding process of the plate body; the nucleating agent includes at least one of the following: calcium carbonate, silicon dioxide, calcium oxide; the weight percentage of the added nucleating agent is 0.1%-0.5%.

[0025] In one embodiment, the plate body is a multi-layer structure formed by co-extruding at least two or more different materials.

[0026] To achieve the above object, the present invention provides a method for manufacturing a quantum dot diffusion plate, which includes the following steps: First, a plate body is manufactured through a foaming extrusion molding process. The plate body has an upper surface and a lower surface, and a plurality of micro-structures are extruded on at least the upper surface of the plate body. A plurality of the micro-structures are arranged in an array form on the upper surface of the plate body and form a plurality of convex portions and a plurality of concave portions on the upper surface of the plate body. A plurality of the concave portions are separated by a plurality of the convex portions, so a plurality of the concave portions are independent of each other and do not communicate with each other. Then, a quantum dot layer is coated at a plurality of the concave portions on the upper surface of the plate body through a coating process. Wherein, the thickness of the quantum dot layer is t1, the distance from the top of a plurality of the convex portions to the bottom of a plurality of the concave portions is t2, and t1 < t2. After that, through an adhesion process, a water and gas barrier layer is attached to the upper surface of the plate body and covers a plurality of the convex portions and the quantum dot layer. Description of the Drawings

[0027] Figure 1 It is a schematic cross-sectional view of an embodiment of the quantum dot light diffusion plate of the present invention installed on a backlight module.

[0028] Figure 2 It is a schematic three-dimensional exploded view of an embodiment of the quantum dot light diffusion plate of the present invention installed on a backlight module.

[0029] Figures 3A to 3E They are respectively schematic views of several different embodiments of the micro-structure of the quantum dot light diffusion plate of the present invention.

[0030] Figure 4 It is a schematic cross-sectional view of another embodiment of the quantum dot light diffusion plate of the present invention installed on a backlight module.

[0031] Explanation of the reference numerals: 20 - substrate; 21 - light-emitting element; 211 - blue light; 212 - white light; 10 - board body; 101 - main board layer; 102 - upper surface layer; 103 - lower surface layer; 11 - microstructure; 111 - convex portion; 112 - concave portion; 12 - quantum dot layer; 120 - quantum dots; 13 - water- and gas-blocking layer; 100 - microbubbles. DETAILED DESCRIPTION

[0032] The present invention relates to a quantum dot light diffusion plate and a method for making the same. The diffusion plate can be assembled on a backlight module with a blue light emitting diode (LED) as a lower light source. A plurality of microstructures having a plurality of concave portions and convex portions are formed on the surface of the diffusion plate, and a quantum dot layer including a plurality of green quantum dots and a plurality of red quantum dots is coated in the plurality of concave portions of the plurality of microstructures, and then a water- and gas-blocking layer is disposed on the upper surface of the quantum dot layer. The plurality of convex portions of the plurality of microstructures are used to separate the quantum dot layers located in the plurality of concave portions so that they are each independent, so that external water vapor and oxygen cannot penetrate the four side end faces of the quantum dot layer and invade the entire quantum dot layer, which has the advantages of simple process, low cost and high production qualification rate. The present invention attaches a water-blocking and gas-blocking film to the upper surface of the diffusion plate, and blocks water vapor from entering the quantum dot layer from the side end face through a microstructure, so that the distance for water vapor to enter the quantum dot layer from the end face is reduced to a minimum. Moreover, since it is extruded in one piece, the subsequent processing process and production cost can be reduced, and a relatively high production qualification rate can be achieved.

[0033] In order to more clearly describe the quantum dot light diffuser plate and the manufacturing method thereof proposed by the present invention, they are described in detail with reference to the drawings below.

[0034] See also Figure 1 and Figure 2 The figures are respectively a cross-sectional schematic diagram and a three-dimensional exploded schematic diagram of an embodiment of the quantum dot light diffuser of the present invention installed on a backlight module. In this embodiment, the backlight module of the present invention includes, from bottom to top, a substrate 20, a plurality of light-emitting elements 21, and a diffuser. The diffuser includes: a plate body 10, a plurality of micro-structures 11, a quantum dot layer 12, and a water- and gas-blocking layer 13.

[0035] A circuit layout is provided on the substrate 20, and a plurality of light-emitting elements 21 are arranged on the substrate 20 in an array form and electrically coupled to the circuit layout. In the present invention, the plurality of light-emitting elements 21 are blue light-emitting diodes (LEDs), which can emit blue light 211 upward toward the plate body 10 of the diffusion plate. In this embodiment, the plurality of light-emitting elements 21 can be conventional blue LEDs, blue Mini LEDs, or even blue Micro LEDs. A reflective layer (not numbered) is provided on the top surface of the substrate 20, and the reflective layer can be white or other colors or surfaces with better light reflection effects, for reflecting light upward toward the plate body 10 of the diffusion plate. The base material of the plate body 10 of the diffusion plate can be an amorphous or semi-crystalline plasticized material, and its material includes at least one of the following: polycarbonate (PC), polystyrene (PS), polymethyl methacrylate (PMMA, commonly known as acrylic), polyethylene (PE), polypropylene (PP), polyethylene terephthalate (PET), or a copolymer of any of the foregoing materials. In this embodiment, the plate body 10 is a single-layer plate structure based on polystyrene (PS), and its thickness is preferably between 0.8 mm and 2.5 mm. The plate body 10 of the diffusion plate is located above the substrate 20 and adjacent to the substrate 20, and generally there are no other elements between the plate body 10 of the diffusion plate and the light-emitting elements 21 provided on the substrate 20. The quantum dot layer 12 requires a consistent blue light intensity to convert red / green light and mix it into uniform white light; due to the lower ambient light intensity compared to the central intensity of the display, there is easily insufficient red / green light conversion, resulting in a blue light leakage phenomenon around the display. The plate body 10 of the present invention is formed by foaming extrusion, and a plurality of microbubbles 100 are included in the plate body 10, which has a higher light refraction effect, improves the light intensity in the surrounding area of the display, and thus improves the blue light leakage problem. In one embodiment, diffusion particles can be added to the plate body 10 of the diffusion plate of the present invention, and the diffusion particles can be known types on the market, for further improving the light diffusion effect of the diffusion plate.

[0036] In this embodiment, the feasible range of the weight reduction rate of the plurality of microbubbles 100 for the plate body 10 is between 10% and 35%, but the preferred range of the weight reduction rate is between 15% and 25%, and the average size of the plurality of microbubbles 100 is between 60 and 800 μm; wherein, the calculation formula of the weight reduction rate is:

[0037] Weight reduction rate (%) = (W1 - W2) / W2 * 100%;

[0038] W1 = H * (L1 * L2 * D);

[0039] Wherein:

[0040] H is the average thickness (mm) of the plate body;

[0041] L1 is the length (mm) of the plate body;

[0042] L2 is the width (mm) of the plate body;

[0043] D is the raw material specific gravity (g / mm 3 ) of the plate body;

[0044] W1 is the theoretical weight (g) of the plate body, that is, the weight without a plurality of the microbubbles;

[0045] W2 is the actual weight (g) of the plate body, that is, the actual weight of the plate body containing a plurality of the microbubbles actually measured with a weighing scale.

[0046] In this embodiment, a plurality of the microbubbles 100 are generated by appropriately adding a foaming agent and a nucleating agent in the foam extrusion molding process of the plate body 10; the nucleating agent includes at least one of the following: calcium carbonate, silicon dioxide, calcium oxide; the applicable range of the weight percentage of the added nucleating agent is 0.01%-5%, but the preferred range is 0.1%-0.5%. The weight reduction rate of the microbubbles 100 can be controlled by the amount of the added foaming agent, and the method for controlling the bubble diameter of the microbubbles 100 can be the addition of the nucleating agent and the adjustment of the process temperature.

[0047] In this embodiment, the diffusion plate includes: a plate body 10, a plurality of micro-structures 11 (Micro-Structures), a quantum dot layer 12, and a water and oxygen barrier layer 13. The plate body 10 has an upper surface and a lower surface, and the lower surface faces the substrate 20. The plurality of micro-structures 11 are arranged in an array on the upper surface of the plate body 10, and a plurality of convex portions 111 and a plurality of concave portions 112 are formed on the upper surface of the plate body 10. The plurality of concave portions 112 are separated by the plurality of convex portions 111, so the plurality of concave portions 112 are independent of each other and do not communicate with each other. The quantum dot layer 12 is disposed at the plurality of concave portions 112 on the upper surface of the plate body 10, and the quantum dot layer 12 is not disposed at the plurality of convex portions 111. Wherein, the thickness of the quantum dot layer 12 is t1, and the distance from the top of one of the plurality of convex portions 111 to the bottom of one of the plurality of concave portions 112 is t2, and t1 < t2. In other words, the height t2 of the convex portion 111 of the micro-structure 11 is greater than the thickness t1 of the quantum dot layer 12, so that the quantum dot layers 12 located in different concave portions 112 do not communicate with each other and do not contact the water and oxygen barrier layer 13 is disposed on the entire upper surface of the plate body 10 and closely covers the plurality of convex portions 111 and the quantum dot layer 12. Through the water and oxygen barrier layer 13, external water vapor and oxygen can be isolated and prevented from invading the upper surface of the quantum dot layer 12. The thickness of the water and oxygen barrier layer 13 is t3, and it can be selected from commercially available water and oxygen barrier films and directly adhered to the convex portions 111 of the plurality of micro-structures 11 and the quantum dot layer 12 on the upper surface of the plate body 10. The distance between two adjacent convex portions 111 is P. In this embodiment,

[0048] The quantum dot layer 12 contains a plurality of quantum dots 120 (Quantum Dot; hereinafter referred to as QD). The plurality of quantum dots 120 can be selected from commercially available nanocrystalline semiconductor materials composed of II-VI, III-V, or IV-VI group elements, and the grain diameter of each quantum dot 120 is between 2 and 10 nm. Among them, the emission wavelength of the plurality of quantum dots 120 in the quantum dot layer 12 can be between 490 and 650 nm; in this embodiment, the plurality of quantum dots 120 include a plurality of green quantum dots with an emission wavelength of 520 to 530 nm and a plurality of red quantum dots with an emission wavelength of 620 to 630 nm. The blue light 211 emitted upward by the light-emitting element 21 can be mixed into white light 212 and emitted upward from the upper surface of the plate body 10 after passing through the quantum dot layer 12.

[0049] In this embodiment, the feasible range of the thickness t1 of the quantum dot layer 12 is between 5 and 150 μm, but the preferred feasible range is that t1 is between 10 and 40 μm. The feasible range of the distance from the tops of the plurality of convex portions 111 to the bottoms of the plurality of concave portions 112 (or the height of the convex portion, which can be called) t2 is between 6 and 200 μm, but the preferred feasible range is that t2 is between 25 and 50 μm; and, t1 < t2. The feasible range of the thickness t3 of the water and gas barrier layer 13 is between 5 and 100 μm, but the preferred feasible range is that t3 is between 10 and 30 μm. The maximum width of the convex portion 111 is between 50 and 500 μm. The feasible range of the distance P between two adjacent convex portions 111 is between 50 and 1000 μm, but the preferred feasible range is that P is between 250 and 500 μm.

[0050] Please refer to Figures 3A to 3E , which are schematic diagrams of several different embodiments of the microstructure of the quantum dot light diffusing plate of the present invention. In the present invention, the plurality of microstructures include a plurality of N-sided pyramids, where N is a positive integer greater than or equal to three; and the plurality of microstructures can be composed of pyramids of a single shape or a combination of two or more different shapes of pyramids. The name of the pyramid varies according to the shape of the bottom surface and depends on the bottom polygon; for example, a pyramid with a triangular bottom surface is called a triangular pyramid, and a pyramid with a square bottom surface is called a square pyramid, and so on. A pyramid with an N-sided bottom surface has a total of N + 1 vertices, N + 1 faces, and 2N edges. The dual polyhedron of a pyramid is a pyramid of the same shape. For example, the dual polyhedron of a square pyramid is an inverted square pyramid. As Figure 3A shown in the embodiment, each microstructure presents a triangular pyramid (N = 3) in the top view. As Figure 3B shown, the plurality of microstructures include a combination of two different pyramids, namely a hexagonal pyramid (N = 6) and a triangular pyramid (N = 3) presented in the top view. As Figure 3C shown, each microstructure presents a quadrilateral pyramid (N = 4), that is, a square pyramid or a pyramidal pyramid, in the top view. As Figure 3D shown, the plurality of microstructures include a combination of two different pyramids, namely a quadrilateral pyramid (N = 4) and a triangular pyramid (N = 3) presented in the top view. As Figure 3E shown, each microstructure presents a quadrilateral pyramid (N = 4), that is, a square pyramid or a pyramidal pyramid shape, but the width of the convex portion of each microstructure in the Y-axis direction is greater than the width of the convex portion in the X-axis direction.

[0051] The present invention sets several types of pyramid-shaped microstructures with different depths on the upper surface of the diffusion plate body to cooperate with a quantum dot (QD) layer of the same thickness for testing, so as to compare the degree of edge failure achieved by microstructures with different depths after environmental testing. Table 1 below shows the structural information of each comparative example for testing. For example, the upper surface of the diffusion plate of Comparative Example 1 is "flat", so the depth and spacing values of its surface microstructure are both "NA", that is, 0. In other words, the quantum dot (QD) layer is attached to the upper surface of the diffusion plate in the form of a whole flat QD film, and the thickness of the QD film is 20 μm. After the environmental test of 60 °C, 90% RH - 1000 hr for Comparative Example 1, it is found that the degree of edge failure of the quantum dot layer at the four peripheral edges of the diffusion plate reaches a width of 1 cm. The upper surface of the diffusion plate of Comparative Example 2 is "matte", and the depth of its surface microstructure is the matte level of "Ra15". In other words, the quantum dot (QD) layer is coated on the upper surface of the diffusion plate in a whole surface form, and the thickness of the QD layer is 20 μm. After the environmental test of 60 °C, 90% RH - 1000 hr for Comparative Example 2, it is found that the degree of edge failure of the quantum dot layer at the four peripheral edges of the diffusion plate reaches a width of 1 cm. The depth of the microstructure set on the upper surface of the diffusion plate of Comparative Example 3 is only 5 μm, while the thickness of the quantum dot (QD) layer is 20 μm. In other words, the thickness of the quantum dot (QD) layer is greater than the depth of the microstructure. After the environmental test of 60 °C, 90% RH - 1000 hr for Comparative Example 3, it is found that the degree of edge failure of the quantum dot layer at the four peripheral edges of the diffusion plate reaches a width of 1 cm. The depth of the microstructure set on the upper surface of the diffusion plate according to Example 1 of the present invention is 30 μm, while the thickness of the quantum dot (QD) layer is 20 μm. In other words, the thickness of the quantum dot (QD) layer is less than the depth of the microstructure. After the environmental test of 60 °C, 90% RH - 1000 hr for Example 1, it is found that the degree of edge failure of the quantum dot layer at the four peripheral edges of the diffusion plate is only 0.2 cm wide. It can be seen that when the thickness of the quantum dot (QD) layer is less than the depth of the microstructure (such as Example 1), the degree of edge failure of the quantum dot layer can be greatly reduced. The upper and lower surfaces of the diffusion plate according to Example 2 of the present invention are both provided with microstructures and QD layers. The depths of the microstructures on the upper and lower surfaces are both 30 μm, while the thicknesses of the quantum dot (QD) layers on the upper and lower surfaces are 15 μm. In other words, the thickness of each quantum dot (QD) layer is not only less than the depth of the microstructure but also smaller than the thickness of the quantum dot layer in Example 1. After the environmental test of 60 °C, 90% RH - 1000 hr for Example 2, it is found that the degree of edge failure of the quantum dot layer at the four peripheral edges of the diffusion plate is only 0.15 cm wide (due to the reduction of the thickness of each quantum dot layer), and the luminance is increased to 380 cd / m 2 (because the microstructures and quantum dot layers are provided on both the upper and lower surfaces of the diffusion plate), and its performance is better than that of Example 1. It can be seen that when the microstructures and quantum dot layers are provided on both the upper and lower surfaces of the diffusion plate (such as Example 2), better effects can be achieved.

[0052] Table 1: Comparison table of the edge failure degrees caused by different depths of microstructures on the surface of the diffusion plate after environmental testing

[0053]

[0054] In the present invention, by adding diffusion particles and a foaming agent into the plate body of the diffusion plate to generate microbubbles, the light diffusion effect is improved and the distance of blue light leakage around the backlight module is reduced. The applicant of the present invention provides multiple diffusion plates with different weight ratios of the foaming agent added to achieve different microbubble weight reduction ratios (Examples 3 to 4 and Comparative Examples 4 to 8 shown in Table 2), and measures the distance of blue light leakage around and the luminance value after each diffusion plate is assembled in the backlight module, so as to compare the comparison relationship between the weight reduction ratio (%) of the microbubbles contained in the diffusion plate and the distance of blue light leakage around the backlight module and the luminance value. Table 2 below shows the structural information of each diffusion plate example for testing and comparison. It can be seen from Table 2 that different addition ratios of the foaming agent result in different proportions of microbubbles in the plate body of the diffusion plate, which will affect the performance of the light emission uniformity (MURA) of the backlight module provided with the diffusion plate. The more the addition ratio of the foaming agent, although the MURA shielding effect is good, it will cause too much luminance loss (<3%). Among them, the weight reduction ratio of 15 to 25% is better. For example, in Comparative Examples 5 to 6 and Example 4, relatively optimal comprehensive performance can be achieved in terms of luminance and MURA shielding effect.

[0055] Table 2: Comparison table of the diffusion plate containing different microbubble weight reduction ratios with respect to the luminance value and the distance of blue light leakage around

[0056]

[0057]

[0058] In an embodiment of the present invention, the method for manufacturing the quantum dot light diffusing plate includes the following steps: First, a plate body is manufactured through a foaming extrusion molding process. The plate body has an upper surface and a lower surface, and a plurality of micro-structures are extruded on at least the upper surface of the plate body. The plurality of micro-structures are arranged in an array form on the upper surface of the plate body and form a plurality of convex portions and a plurality of concave portions on the upper surface of the plate body. The plurality of concave portions are separated by the plurality of convex portions, so the plurality of concave portions are independent of each other and do not communicate with each other. Then, a quantum dot layer is coated at the plurality of concave portions on the upper surface of the plate body through a coating process. Wherein, the thickness of the quantum dot layer is t1, the distance from the top of the plurality of convex portions to the bottom of the plurality of concave portions is t2, and t1 < t2. After that, through an adhesion process, a water and gas barrier layer is attached to the upper surface of the plate body and covers the plurality of convex portions and the quantum dot layer. The present invention prevents water vapor from invading the quantum dot layer from the upper surface by attaching a water and gas barrier film to the upper surface of the diffusing plate, and blocks the entry of water vapor from the side end faces through the convex portions of the micro-structures, minimizing the distance for water vapor to enter the quantum dot layer from the end faces. And, since the diffusing plate is integrally formed by extrusion, subsequent processing processes and production costs can be reduced, and a relatively high production qualification rate can be achieved.

[0059] Please refer to Figure 4 , which is a schematic cross-sectional view of another embodiment of the quantum dot light diffusing plate of the present invention installed on a backlight module. Since Figure 4 the structures and functions of most components in the illustrated embodiment are the same as those in Figure 1 the illustrated embodiment, the same or similar components will be directly given the same component names and numbers, and their details will not be described in detail. In the Figure 4 illustrated embodiment, the plate body 10 is a multi-layer structure formed by co-extrusion of different materials including at least two layers (main board layer 101, upper surface layer 102, lower surface layer 103) or more, and a plurality of micro-structures 11, quantum dot layers 12, and water and gas barrier layers 13 are respectively arranged on the upper and lower surfaces of the plate body 10. In other words, Figure 4 in the illustrated embodiment, in addition to setting on the upper surface of the plate body 10 the same as Figure 1In addition to a plurality of microstructures 11, a quantum dot layer 12, and a water and gas barrier layer 13 that are the same as those in the illustrated embodiment, a plurality of the microstructures 11, the quantum dot layer 12, and the water and gas barrier layer 13 are also provided on the lower surface of the plate body 10. The plurality of microstructures 11 form a plurality of convex portions 111 and a plurality of concave portions 112 on the lower surface of the plate body 10. The plurality of concave portions 112 are separated by the plurality of convex portions 111, so that the plurality of concave portions 112 on the lower surface of the plate body 10 are independent of each other and do not communicate with each other. Moreover, the quantum dot layer 12 located on the lower surface of the plate body 10 is disposed at the plurality of concave portions 112 on the lower surface of the plate body 10. In addition, the water and gas barrier layer 13 on the lower surface of the plate body 10 covers the plurality of convex portions 111 and the quantum dot layer 12 on the lower surface of the plate body 10. In this embodiment, the structures of the plurality of microstructures 11, the quantum dot layer 12, and the water and gas barrier layer 13 provided on the upper and lower surfaces of the plate body 10 are substantially the same, and the thickness of the quantum dot layer 12 is also less than the height of the convex portions 111 of the microstructures 11.

[0060] The embodiments described above are not intended to limit the scope of application of the present invention. The protection scope of the present invention shall be based on the technical spirit defined by the content of the claims of the present invention and the scope covered by its equivalent variations. That is, all equivalent changes and modifications made in accordance with the claims of the present invention will still not lose the essence of the present invention, nor depart from the spirit and scope of the present invention, and therefore should all be regarded as further implementation situations of the present invention.

Claims

1. A quantum dot light diffusing plate for combination with a backlight module; the backlight module includes: A substrate and a plurality of blue light emitting elements are arranged on the substrate in an array form; it is characterized in that the diffusion plate is located above the substrate and includes: A plate body having an upper surface and a lower surface, and the lower surface faces the substrate; A plurality of microstructures are arranged on the upper surface of the plate body in an array form; the plurality of microstructures form a plurality of convex portions and a plurality of concave portions on the upper surface of the plate body, and the plurality of concave portions are separated by the plurality of convex portions, so that the plurality of concave portions are independent of each other and do not communicate with each other; A quantum dot layer is arranged at the plurality of concave portions on the upper surface of the plate body; wherein, the thickness of the quantum dot layer is t1, and the distance from the top of one of the plurality of convex portions to the bottom of one of the plurality of concave portions is t2, and t1 < t2; and A water and oxygen barrier layer is arranged on the upper surface of the plate body and covers the plurality of convex portions and the quantum dot layer; Wherein, the plate body is formed by foam extrusion molding, and a plurality of microbubbles are included in the plate body; the weight reduction rate of the plurality of microbubbles for the plate body is between 15% and 25%, and the average size of the plurality of microbubbles is between 60 and 800 μm; Wherein, the calculation formula of the weight reduction rate is: Weight reduction rate (%) = (W1 - W2) / W2 * 100%; W1 = H * (L1 * L2 * D); Wherein: H is the average thickness of the plate body; L1 is the length of the plate body; L2 is the width of the plate body; D is the raw material specific gravity of the plate body; W1 is the theoretical weight of the plate body, that is, the weight when not including the plurality of microbubbles; W2 is the actual weight of the plate body, that is, the actual weight of the plate body including the plurality of microbubbles actually weighed with a scale.

2. The quantum dot light diffusing plate according to claim 1, wherein A plurality of the microstructures, the quantum dot layer and the water and oxygen barrier layer are also arranged on the lower surface of the plate body; the plurality of microstructures form a plurality of the convex portions and a plurality of the concave portions on the lower surface of the plate body, and the plurality of concave portions are separated by the plurality of convex portions, so that the plurality of concave portions on the lower surface of the plate body are independent of each other and do not communicate with each other; and, the quantum dot layer located on the lower surface of the plate body is arranged at the plurality of concave portions on the lower surface of the plate body; in addition, the water and oxygen barrier layer on the lower surface of the plate body covers the plurality of convex portions and the quantum dot layer on the lower surface of the plate body.

3. The quantum dot light diffusing plate according to claim 1, wherein A plurality of quantum dots are included in the quantum dot layer; the plurality of quantum dots are a kind of nano microcrystalline semiconductor material, composed of II-VI, III-V or IV-VI group elements, and the grain diameter of each of the quantum dots is between 2 and 10 nm; wherein, the plurality of quantum dots include a plurality of green quantum dots with a light emission wavelength of 520 - 530 nm and a plurality of red quantum dots with a light emission wavelength of 620 - 630 nm.

4. The quantum dot light diffusion plate according to claim 1, wherein, The plurality of microstructures include a plurality of N-sided pyramids, where N is a positive integer greater than or equal to three; t2 is between 6 and 200 μm; the thickness of the water and oxygen barrier layer is t3, and t3 is between 5 and 100 μm.

5. The quantum dot light diffusing plate according to claim 4, wherein t2 is between 25 and 50 μm, t1 is between 10 and 40 μm, and t3 is between 10 and 30 μm.

6. The quantum dot light diffusing plate according to claim 1, wherein The maximum width of the convex part is between 50 and 500 μm, and the distance between two adjacent convex parts is between 50 and 1000 μm.

7. The quantum dot light diffusion plate according to claim 1, wherein The material of the plate body includes one of the following: polycarbonate, polystyrene, polymethyl methacrylate, polyethylene, polypropylene, polyethylene terephthalate.

8. The quantum dot light diffusing plate according to claim 1, wherein, A plurality of the microbubbles are generated by adding a foaming agent and a nucleating agent in the foaming extrusion molding process of the plate body; the nucleating agent includes at least one of the following: calcium carbonate, silicon dioxide, calcium oxide; the weight percentage of the added nucleating agent is 0.1%-0.5%.

9. The quantum dot light diffusing plate according to claim 1, wherein, The plate body is a multi-layer structure formed by co-extrusion of at least two different materials.

10. A method for manufacturing a quantum dot light diffusing plate, characterized in that, Including: Manufacturing a plate body through a foaming extrusion molding process. The plate body has an upper surface and a lower surface, and a plurality of microbubbles are included in the plate body; and, a plurality of microstructures are extruded on at least the upper surface of the plate body; the plurality of microstructures are arranged in an array on the upper surface of the plate body and form a plurality of convex parts and a plurality of concave parts on the upper surface of the plate body; the plurality of concave parts are separated by the plurality of convex parts, so the plurality of concave parts are independent of each other and do not communicate with each other; Coating a quantum dot layer on the plurality of concave parts on the upper surface of the plate body through a coating process; wherein, the thickness of the quantum dot layer is t1, the distance from the top of one of the plurality of convex parts to the bottom of one of the plurality of concave parts is t2, and, t1 < t2; and Through an adhesion process, a water and gas barrier layer is attached to the upper surface of the plate body and covers the plurality of convex parts and the quantum dot layer Wherein, the weight reduction rate of the plurality of microbubbles for the plate body is between 15% and 25%, and the average size of the plurality of microbubbles is between 60 and 800 μm; Wherein, the calculation formula of the weight reduction rate is: Weight reduction rate (%) = (W1 - W2) / W2 * 100%; W1 = H * (L1 * L2 * D); Where: H is the average thickness of the plate body; L1 is the length of the plate body; L2 is the width of the plate body; D is the raw material specific gravity of the plate body; W1 is the theoretical weight of the plate body, that is, the weight without the plurality of microbubbles; W2 is the actual weight of the plate body, that is, the actual weight of the plate body containing the plurality of microbubbles measured by a weighing scale.

11. The method for manufacturing a quantum dot light diffusing plate according to claim 10, wherein, A plurality of the microstructures, the quantum dot layer, and the water and gas barrier layer are also provided on the lower surface of the plate body; the plurality of microstructures form a plurality of convex parts and a plurality of concave parts on the lower surface of the plate body, and the plurality of concave parts are separated by the plurality of convex parts, so the plurality of concave parts on the lower surface of the plate body are independent of each other and do not communicate with each other; and, the quantum dot layer located on the lower surface of the plate body is provided at the plurality of concave parts on the lower surface of the plate body; in addition, the water and gas barrier layer on the lower surface of the plate body covers the plurality of convex parts and the quantum dot layer on the lower surface of the plate body.

12. The manufacturing method of the quantum dot light diffusing plate according to claim 10, characterized in that, The quantum dot layer contains a plurality of quantum dots; the plurality of quantum dots are a kind of nano-microcrystalline semiconductor material composed of elements of II-VI, III-V or IV-VI groups, and the grain diameter of each of the quantum dots ranges from 2 to 10 nm; wherein, the plurality of quantum dots include a plurality of green quantum dots with a light emission wavelength of 520-530 nm and a plurality of red quantum dots with a light emission wavelength of 620-630 nm.

13. The manufacturing method of the quantum dot light diffusing plate according to claim 10, characterized in that, The plurality of microstructures include a plurality of N-sided pyramids, where N is a positive integer greater than or equal to three; t2 ranges from 6 to 200 μm; the thickness of the water and gas barrier layer is t3, and t3 ranges from 5 to 100 μm.

14. The manufacturing method of the quantum dot light diffusing plate according to claim 10, characterized in that, t2 ranges from 25 to 50 μm, t1 ranges from 10 to 40 μm, and t3 ranges from 10 to 30 μm.

15. The manufacturing method of the quantum dot light diffusion plate according to claim 10, wherein, The maximum width of the convex portion ranges from 50 to 500 μm, and the distance between two adjacent convex portions ranges from 50 to 1000 μm.

16. The manufacturing method of the quantum dot light diffusing plate according to claim 10, characterized in that, The material of the plate body includes one of the following: polycarbonate, polystyrene, polymethyl methacrylate, polyethylene, polypropylene, polyethylene terephthalate.

17. The manufacturing method of the quantum dot light diffusing plate according to claim 10, characterized in that, The plurality of microbubbles are generated by adding a foaming agent and a nucleating agent during the foam extrusion molding process of the plate body; the nucleating agent includes at least one of the following: calcium carbonate, silicon dioxide, calcium oxide; the weight percentage of the added nucleating agent is 0.1%-0.5%.

18. The manufacturing method of the quantum dot light diffusing plate according to claim 10, characterized in that, The plate body is a multi-layer structure formed by co-extrusion of at least two or more different materials.

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