Anti-dazzle uniform light type quantum dot backlight module composite diffusion film, preparation method thereof and backlight module
Patent Information
- Application Number
- CN202611520101.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2026-09-29
- Publication Date
- 2026-11-03
AI Technical Summary
Mini-LED backlight modules suffer from glare and uneven quantum dot excitation caused by direct blue light at small angles, and traditional solutions struggle to balance ultra-thin design with low-cost production.
The system employs a stacked microstructure light-uniforming film and a multilayer directional blue light-reflecting film. The microstructure light-uniforming film is used for initial light homogenization, while the multilayer directional blue light-reflecting film reflects direct blue light at a small angle and homogenizes it a second time. Combined with high and low refractive index resin materials such as PET or PEN and PMMA, it forms an effective optical interference reflection. A microlens array is used to further homogenize the light distribution.
It effectively suppresses glare and quantum dot excitation unevenness caused by direct blue light at small angles, improves light utilization efficiency, reduces process complexity and cost, and achieves uniformity and high-efficiency optical performance of emitted light.
Smart Images
Figure CN123029651A_ABST
Abstract
Description
Technical Field
[0001] This application relates to the technical field of LCD display panels, and in particular to an anti-glare and uniform light quantum dot backlight module composite diffusion film, its preparation method, and the backlight module. Background Technology
[0002] In recent years, Mini-LED combined with quantum dot display technology has become the mainstream due to its advantages such as local dimming, high brightness, low power consumption and long lifespan, but its large-scale promotion still faces many bottlenecks.
[0003] The point light source characteristics of Mini-LEDs result in a high concentration of direct blue light (450-475nm) within a 0-30° range, which can easily cause local over-excitation of the quantum dot film, leading to problems such as visual glare, poor color stability, and blue fringing at the edges. To achieve uniform illumination, traditional solutions either use a 2-3mm thick scattering diffuser film, which severely limits the ultra-thin design of the equipment; or rely on high-precision alignment between the LED chip and the mask, which significantly increases the complexity of the process and manufacturing costs, making it difficult to guarantee the yield rate; at the same time, to compensate for uneven light distribution, LED chips need to be densely arranged, increasing the chip usage by 30-50%, which not only increases hardware costs but also reduces the energy-saving potential of the product due to the cumulative power consumption.
[0004] To address the aforementioned issues, various improvement solutions have been proposed in the industry, but shortcomings remain. Adding uniform light distribution films or diffusion films to the backlight module can improve the uniformity of light distribution, but these films have limited effectiveness in suppressing intensity in the direct direction of the light source, and the glare problem remains difficult to solve effectively. Blue light filtering films or blue light reflecting films can absorb or reflect blue light in specific wavelengths; however, these films mostly operate across the entire wavelength range, meaning they control the blue light component of the incident light holistically, making it difficult to differentiate the processing of light incident at different angles. Some solutions also have high blue light absorption rates, resulting in low overall light utilization efficiency. Microstructured optical films, which have emerged in recent years, refract and scatter light through surface microlens arrays, which can improve the uniformity of emitted light to some extent. However, their main effect is on adjusting the spatial distribution of light, and their effectiveness in improving the localized high energy density problem caused by small-angle direct blue light is limited. In solutions integrating quantum dot films with homogenizing films and diffusion films into composite films, the homogenizing and diffusion films employ traditional structures, which still lack effective means to suppress the over-excitation of quantum dots caused by direct blue light. Solutions that place reflective bumps or light extraction dots between LED chips primarily improve the light extraction efficiency at the bottom of the backlight module, but have limited ability to control the angle distribution of light rays along the emitted light path.
[0005] Therefore, how to effectively suppress glare and quantum dot excitation unevenness caused by small-angle direct blue light while improving the uniformity of emitted light from Mini-LED backlight modules, and taking into account the requirements of ultra-thin design and low-cost production of backlight modules, is an urgent problem to be solved in this field. Summary of the Invention
[0006] This application provides an anti-glare and uniform light quantum dot backlight module composite diffusion film, its preparation method, and a backlight module, aiming to improve the uniformity of emitted light from the Mini-LED backlight module, suppress glare and uneven excitation of quantum dots caused by small-angle direct blue light, while taking into account the requirements of ultra-thin design and low-cost production of the backlight module.
[0007] In a first aspect, this application provides an anti-glare and uniform light quantum dot backlight module composite diffusion film, which adopts the following technical solution: A composite diffusion film for an anti-glare and light-uniforming quantum dot backlight module includes a microstructured light-uniforming film layer and a multilayer directional blue light reflective film layer stacked together. The multilayer directional blue light reflective film layer is disposed on the light-emitting side of the microstructured light-uniforming film layer, and the side of the microstructured light-uniforming film layer away from the multilayer directional blue light reflective film layer is directed towards the blue light source of the backlight module. The multilayer directional blue light reflective film layer is composed of alternating layers of high birefringence resin and low refractive index resin. The multilayer directional blue light reflective film layer has a reflectivity of greater than or equal to 90% for blue light in the 450nm-475nm wavelength band at an incident angle of 0°-40°, and a full-angle transmittance of greater than or equal to 92% for visible light in the 500nm-780nm wavelength band.
[0008] By adopting the above technical solution, the light emitted by the blue light source is first initially homogenized by a microstructured light-uniforming film layer, and then the 0°-40° small-angle direct blue light is reflected back to the microstructured light-uniforming film layer by a multi-layered directional blue light reflective film layer for secondary homogenization, so that it can be emitted at a larger angle, avoiding glare and local light spots caused by direct high-intensity blue light at small angles; at the same time, the multi-layered directional blue light reflective film layer has a full-angle transmittance of 500nm-780nm visible light greater than or equal to 92%, ensuring efficient emission of visible light and taking into account light utilization efficiency; in addition, this structure does not require high-precision alignment with the LED array, reducing the complexity of the process.
[0009] Optionally, the number of stacked layers of the multilayer directional blue light reflective film is 100-300.
[0010] Optionally, the high birefringence resin layer is made of PET or PEN, and the low refractive index resin layer is made of PMMA.
[0011] By adopting the above technical solution, there is a sufficiently large refractive index difference between PET or PEN and PMMA, which can form effective optical interference reflection. Among them, PEN has a higher refractive index after stretching, which can produce a blue shift effect at different incident angles to match the blue light reflection band and improve the wavelength compatibility of the film. At the same time, the material combination is an optical grade transparent resin with no fluorescence absorption, ensuring that the light utilization efficiency is not less than 92%.
[0012] Optionally, the surface of the microstructure uniform light film layer facing the multilayer directional blue light reflective film layer is provided with a periodically arranged array of microlenses, the microlenses being prism-shaped, and the length and width of the bottom surface of the microlenses being smaller than the emitting surface size of the blue light source of the backlight module.
[0013] By adopting the above technical solution, the bottom surface of the microlens is smaller than the size of the light-emitting surface of the blue light source, so that one light-emitting surface covers multiple microlenses at the same time, and any microlens can receive light from multiple light-emitting surfaces at the same time. The energy distribution of the light emitted by the LED chip is more uniform after being dispersed by multiple microlenses. Effective light uniformity can be achieved without precisely aligning the microlenses with the LED array one by one, which reduces the complexity of the process.
[0014] Optionally, the bottom surface of the microlens has a length and width of 50μm-100μm, the height of the microlens has a height of 5μm-25μm, the center-to-center distance between adjacent microlenses has a distance of 5μm-10μm, and the top angle of the microlenses is 145°.
[0015] Optionally, the material of the microstructured light-uniforming film layer is optical-grade transparent resin, the refractive index of the optical-grade transparent resin is 1.42-1.56, and the uniformity of the emitted light of the microstructured light-uniforming film layer is greater than or equal to 94%.
[0016] Optionally, the total thickness of the microstructure uniform light film layer and the multilayer directional blue light reflective film layer is less than or equal to 80 μm.
[0017] Secondly, this application provides a method for preparing a composite diffusion film for an anti-glare and uniform light quantum dot backlight module, employing the following technical solution: A method for preparing an anti-glare and uniform light-emitting quantum dot backlight module composite diffusion film includes the following steps: S1. The high birefringence resin layer material and the low refractive index resin layer material are alternately stacked and cast, and after biaxial stretching, a multi-layer directional blue light reflective film layer is formed. S2. Optical grade transparent resin is hot-pressed to form a microstructured light-uniforming film layer with a microlens array on the surface. S3. The microstructure uniform light film layer and the multilayer directional blue light reflective film layer are bonded together with optical adhesive, so that the multilayer directional blue light reflective film layer is located on the light-emitting side of the microstructure uniform light film layer, thereby obtaining an anti-glare uniform light quantum dot backlight module composite diffusion film.
[0018] Thirdly, this application provides a backlight module, which adopts the following technical solution: A backlight module includes a blue light source layer, a quantum dot film layer, and a composite diffusion film disposed between the blue light source layer and the quantum dot film layer. The composite diffusion film is the aforementioned anti-glare and light-uniforming quantum dot backlight module composite diffusion film. The microstructure light-uniforming film layer is close to the blue light source layer, and the multilayer directional blue light reflective film layer is close to the quantum dot film layer.
[0019] In summary, this application includes at least one of the following beneficial technical effects: 1. The light emitted from the blue light source is first initially homogenized by a microstructured light-diffusing film layer. Then, a multi-layered directional blue light reflective film layer reflects the blue light directly incident at a small angle (0°-40°) back to the microstructured light-diffusing film layer for secondary homogenization, allowing it to be emitted at a larger angle. This avoids glare and localized light spots caused by direct exposure of high-intensity blue light at small angles. At the same time, the multi-layered directional blue light reflective film layer has a transmittance of greater than or equal to 92% for visible light in the 500nm-780nm range, ensuring efficient emission of visible light and taking into account light utilization efficiency. In addition, this structure does not require high-precision alignment with the LED array, reducing the complexity of the manufacturing process. 2. The refractive index difference between PET or PEN and PMMA is large enough to form effective optical interference reflection; PEN has a higher refractive index after stretching, which can produce a blue shift effect at different incident angles to match the blue light reflection band and improve the wavelength compatibility of the film. 3. The bottom surface of the microlens is smaller than the size of the light-emitting surface of the blue light source, so that one light-emitting surface can cover multiple microlenses at the same time, and any microlens can receive light from multiple light-emitting surfaces at the same time. The energy distribution of the light emitted from the LED chip is more uniform after being dispersed by multiple microlenses. Effective light uniformity can be achieved without precisely aligning the microlenses with the LED array one by one, which reduces the complexity of the process. Attached Figure Description
[0020] Figure 1 This is a schematic diagram of the layered structure of an anti-glare and uniform light quantum dot backlight module composite diffusion film in an LCD display panel, as described in Embodiment 2 of this application.
[0021] Figure 2 This is a schematic diagram of the morphology of the microlens array on the surface of the microstructure uniform light film layer in Embodiment 2 of this application.
[0022] Figures 3 to 5 This is a simulation diagram of light source illumination on the microstructure homogenizing film layer in Embodiment 2 of this application under different angles between the tops of the microprisms, wherein... Figure 3 This is a schematic diagram of the light source distribution when the top angle is 122°. Figure 4 This is a schematic diagram of the light source distribution when the top angle is 145°. Figure 5This is a schematic diagram of the light source distribution when the top angle is 165°.
[0023] Figure 6 This is the optical reflection spectrum of the multilayer directional blue light reflective film in Embodiment 2 of this application in the 450nm-475nm wavelength band. Detailed Implementation
[0024] This application discloses an anti-glare, uniform light quantum dot backlight module composite diffusion film.
[0025] Example 1:
[0026] Example 1 describes a composite diffusion film for an anti-glare, uniform-light quantum dot backlight module, comprising multiple layers of directional blue light reflective film. These multiple layers are composed of alternating layers of high birefringence resin and low refractive index resin. The multiple layers of directional blue light reflective film are positioned between the Mini-LED blue light source layer and the quantum dot film.
[0027] In this embodiment, the high birefringence resin layer is made of optical grade PET (Wanhua, refractive index 1.65), and the low refractive index resin layer is made of optical grade PMMA (Wanhua, refractive index 1.49).
[0028] An anti-glare and light-uniforming quantum dot backlight module composite diffusion film is prepared by the following steps: S1. PET was pre-crystallized at 120℃ for 2 hours, followed by drying at 120℃ for 4 hours; PMMA was dried at 70℃ for 4 hours. The dried PET and PMMA were fed separately into an extruder, alternately stacked in 200 layers by a casting distributor, and then converged and exited through a die, falling onto a chilling roller for shaping. Subsequently, longitudinal stretching (stretch ratio 3.0:1) and transverse stretching (stretch ratio 3.5:1) were performed sequentially to prepare a multilayer directional blue light reflective film. The total thickness of the resulting multilayer directional blue light reflective film was 22 μm, with PET as the first layer and PET as the side edging layers, each 2 μm thick. The thickness ratio of PET to PMMA was constant at 1.08. The resulting multilayer directional blue light reflective film exhibited an average reflectivity of 85% for blue light in the 450nm-475nm wavelength band at incident angles of 0°-40°, and an average transmittance of 92% for visible light in the 500nm-780nm wavelength band across all angles. S2. The multilayer directional blue light reflective film obtained in S1 is bonded between the Mini-LED blue light source layer and the quantum dot film layer (InP base, 30μm thickness) using optical pressure-sensitive adhesive (96% transmittance). The bonding pressure is 3MPa, the temperature is 25℃, and the pressure holding time is 30 minutes. After bonding, there are no bubbles or ghosting.
[0029] At room temperature of 25℃, Mini-LED blue light wavelength of 455nm, and light intensity of 3000cd / m² 2The optical performance of the composite diffusion film obtained in this embodiment was tested under the appropriate testing environment. Test results: the average blue light reflectance from 0° to 40° was 85% (450nm-475nm), the average blue light transmittance above 40° was 75% (450nm-475nm), the light utilization efficiency was 92%, the emitted light uniformity was 82%, the glare suppression rate was 84%, the quantum dot excitation intensity difference was 5.7%, and the color gamut coverage of DCI-P3 was 98%.
[0030] Example 2:
[0031] Reference Figure 1 Example 2 describes a composite diffusion film for an anti-glare, uniform-light quantum dot backlight module. This film comprises a stacked microstructure uniform-light film layer and a multilayer directional blue light reflective film layer. The multilayer directional blue light reflective film layer is disposed on the light-emitting side of the microstructure uniform-light film layer. The side of the microstructure uniform-light film layer away from the multilayer directional blue light reflective film layer is directed towards the blue light source of the backlight module. The multilayer directional blue light reflective film layer is composed of alternating layers of high birefringence resin and low refractive index resin.
[0032] In this embodiment, the high birefringence resin layer is made of optical grade PET (Wanhua, refractive index 1.65), and the low refractive index resin layer is made of optical grade PMMA (Wanhua, refractive index 1.49).
[0033] An anti-glare and light-uniforming quantum dot backlight module composite diffusion film is prepared by the following steps: S1. PET was pre-crystallized at 120℃ for 2 hours, followed by drying at 120℃ for 4 hours; PMMA was dried at 70℃ for 4 hours. The dried PET and PMMA were fed separately into an extruder, and after being alternately stacked 200 layers by a casting distributor, they converged and exited through the die, falling onto a chilling roller for shaping. Subsequently, they were subjected to longitudinal stretching (stretch ratio 3.0:1) and transverse stretching (stretch ratio 3.5:1) to prepare a multilayer oriented blue light reflective film. The total thickness of the resulting multilayer oriented blue light reflective film was 22 μm, with PET as the first layer, and PET as the edging layers on both sides, each 2 μm thick. The thickness ratio of PET to PMMA was constant at 1.08.
[0034] S2. Optical-grade PMMA particles are heated to 140°C to melt, and then hot-pressed into shape using a microlens mold. The microprisms in the mold have a 145° angle at the top. The hot-pressing pressure is 8 MPa, and the holding time is 45 seconds. After cooling to room temperature, the film is demolded to form a microstructured homogenizing film layer with a microlens array on its surface. The total thickness of the resulting microstructured homogenizing film layer is 50 μm, the bottom surface of the microlenses is 50 μm × 50 μm, the height is 15 μm, and the center-to-center distance between adjacent microlenses is 8 μm. (Refer to...) Figure 2 The surface of the microstructure homogenizing film layer is provided with a periodically arranged array of prism-shaped microlenses. (Refer to...) Figures 3 to 5 When the included angle at the top of the microprism is 122° ( Figure 3 The light source distribution uniformity is 85%, but there are local light spots; when the included angle at the top of the microprism is 145° ( Figure 4 The light source distribution uniformity is 98%, with no light spots or blue edges, representing the optimal angle; when the included angle at the top of the microprism is 165° ( Figure 5 The light source distribution uniformity is 90%, and there is a slight blue edge at the edge.
[0035] S3. Starting from the side closest to the blue light source, bond the microstructure uniform light film layer and the multilayer directional blue light reflective film layer together using optical pressure-sensitive adhesive (96% transmittance), so that the multilayer directional blue light reflective film layer is located on the light-emitting side of the microstructure uniform light film layer. Then bond it together with the quantum dot film layer (InP-based, 30μm thick). The bonding pressure is 3MPa, the temperature is 25℃, and the pressure holding time is 30 minutes. After bonding, there are no bubbles or ghosting.
[0036] In this embodiment, the LED blue light emitter chip has dimensions of 100μm × 100μm, while the bottom surface of the microlens has dimensions of 50μm × 50μm. This means the bottom surface of the microlens is smaller than the emitting surface size of the LED chip. Based on this dimensional relationship, the emitted light from an LED chip with an emitting surface size of 100μm × 100μm spatially covers approximately 2 × 2 = 4 microlenses, i.e., one emitting surface covers multiple microlenses. Simultaneously, the light received by any microlens originates from multiple LED chips at different locations. This many-to-many spatial correspondence ensures that regardless of the horizontal offset of the microlens array relative to the LED array, each microlens always has one or more LED chips providing a light source, and the emitted light from any LED chip is always dispersed by multiple microlenses. Therefore, this structure achieves uniform light distribution without requiring high-precision alignment with the LED array.
[0037] The optical performance of the composite diffusion film obtained in this embodiment was tested under the following conditions: room temperature 25℃, Mini-LED blue light wavelength 455nm, and light intensity 3000cd / m². Test results: average blue light reflectance of 90% (450nm-475nm) from 0° to 40°, average blue light transmittance of 85% (450nm-475nm) above 40°, light utilization efficiency of 95%, emitted light uniformity of 96%, glare suppression rate of 92%, quantum dot excitation intensity difference of 3.8%, and color gamut coverage of DCI-P3 of 98.5%.
[0038] Example 3:
[0039] In this embodiment, the material of the high birefringence resin layer is optical grade PEN (Wanhua, refractive index 1.75), and the material of the low refractive index resin layer is optical grade PMMA (Wanhua, refractive index 1.49).
[0040] An anti-glare and light-uniforming quantum dot backlight module composite diffusion film is prepared by the following steps: S1. PEN was dried at 140℃ for 6 hours; PMMA was dried at 70℃ for 4 hours. The dried PEN and PMMA were fed into an extruder, and after being alternately stacked 200 layers by a casting distributor, they converged and exited through a die, falling onto a chilling roller for shaping. Subsequently, they were subjected to longitudinal stretching (stretch ratio 3.0:1) and transverse stretching (stretch ratio 3.5:1) to prepare a multilayer oriented blue light reflective film. The total thickness of the resulting multilayer oriented blue light reflective film was 22 μm, with PEN as the first layer and PEN as the edging layers on both sides, each 2 μm thick. The thickness ratio of PEN to PMMA was 1.19. PEN has a higher refractive index than PET, and after biaxial stretching, it exhibits a blue shift effect at different incident angles. At an incident angle of 40°, the blue light reflection band shifts to 430nm-475nm, and at an incident angle of 30°, the blue light reflection band shifts to 440nm-480nm, significantly improving wavelength compatibility.
[0041] S2. Optical-grade PMMA particles are heated to 140°C to melt, and then hot-pressed into shape using a microlens mold. The microprisms in the mold have a top angle of 145°. The hot-pressing pressure is 8 MPa, and the holding time is 45 seconds. After cooling to room temperature, the film is demolded to form a microstructured homogenizing film layer with a microlens array on its surface. The total thickness of the resulting microstructured homogenizing film layer is 50 μm, the bottom surface of the microlenses is 50 μm × 50 μm, the height is 15 μm, and the center-to-center distance between adjacent microlenses is 8 μm.
[0042] S3. Starting from the side closest to the blue light source, bond the microstructure uniform light film layer and the multilayer directional blue light reflective film layer together using optical pressure-sensitive adhesive (96% transmittance), so that the multilayer directional blue light reflective film layer is located on the light-emitting side of the microstructure uniform light film layer. Then bond it together with the quantum dot film layer (InP-based, 30μm thick). The bonding pressure is 3MPa, the temperature is 25℃, and the pressure holding time is 30 minutes. After bonding, there are no bubbles or ghosting.
[0043] In this embodiment, the LED blue light emitter chip has dimensions of 100μm × 100μm, while the bottom surface of the microlens has dimensions of 50μm × 50μm. This means the bottom surface of the microlens is smaller than the emitting surface of the LED chip. Based on this dimensional relationship, this structure can achieve uniform light distribution without requiring high-precision alignment with the LED array.
[0044] The optical performance of the composite diffusion film obtained in this embodiment was tested under the following conditions: room temperature 25℃, Mini-LED blue light wavelength 455nm, and light intensity 3000cd / m². Test results: average blue light reflectance of 90% (450nm-475nm) from 0° to 40°, average blue light transmittance of 85% (450nm-475nm) above 40°, light utilization efficiency of 95%, emitted light uniformity of 98%, glare suppression rate of 95%, quantum dot excitation intensity difference of 3.6%, and color gamut coverage of DCI-P3 of 99%.
[0045] Comparative Example 1: Comparative Example 1 uses a traditional single-layer scattering diffusion film instead of the composite diffusion film in Examples 1-3. A 2mm thick polystyrene (PS) scattering diffusion film is used and bonded between the Mini-LED light source layer and the quantum dot film layer. Performance tests were conducted under the same testing environment, and the results are as follows: average blue light transmittance of 15% (450nm-475nm) from 0° to 40°, light utilization efficiency of 65%, emitted light uniformity of 80%, glare suppression rate of 30%, quantum dot excitation intensity difference of 18.5%, and color gamut coverage of DCI-P3 of 95%.
[0046] Comparative Example 2: A single-layer blue light filter membrane without a microstructure-free uniform light film was used to replace the composite diffusion membrane in Examples 1-3. A traditional organic blue light filter membrane (50 μm thick) was used, which can only absorb blue light in the 450nm-475nm wavelength range, and was bonded between the Mini-LED light source layer and the quantum dot film layer. Performance tests were conducted under the same test environment, and the results are as follows: light utilization efficiency 68%, emitted light uniformity 78%, glare suppression rate 60%, quantum dot excitation intensity difference 15.2%, and quantum dot conversion efficiency 70%.
[0047] The performance test results of Examples 1-3 and Comparative Examples 1-2 are shown in Table 1 below.
[0048] Table 1. Performance test results of Examples 1-3 and Comparative Examples 1-2:
[0049] Combining Examples 1-3 and Comparative Examples 1-2 with Table 1, it can be seen that in Example 1, when only a multilayer directional blue light reflective film layer was set without a microstructured homogenizing film layer, the uniformity of emitted light was only 82%, and the glare suppression effect and quantum dot excitation uniformity were limited. In Example 2, after adding a microstructured homogenizing film layer based on Example 1, the uniformity of emitted light increased to 96%, the glare suppression rate increased to 92%, and the difference in quantum dot excitation intensity decreased from 5.7% to 3.8%, indicating that the combination of the microstructured homogenizing film layer and the multilayer directional blue light reflective film layer significantly improved the performance of the composite diffusion film. In Example 3, after replacing the material of the high birefringence resin layer from PET to PEN, all indicators were further improved, with emitted light uniformity reaching 98%, glare suppression rate reaching 95%, and quantum dot excitation intensity difference at only 3.6%, indicating that the PEN / PMMA material combination further optimized the wavelength compatibility and overall optical performance of the film layer through the blue shift effect.
[0050] In contrast, while the traditional scattering diffuser film in Comparative Example 1 exhibits some light homogenization (outgoing light uniformity of 80%), it cannot suppress direct blue light at small angles, resulting in a glare suppression rate of only 30% and a quantum dot excitation intensity difference as high as 18.5%. Although the blue light filter film in Comparative Example 2 has some absorption effect on blue light, improving the glare suppression rate to 60%, its light utilization efficiency is low (68%), and its light homogenization effect is insufficient (outgoing light uniformity of 78%), with the quantum dot excitation intensity difference still as high as 15.2%.
[0051] In summary, this application achieves significant improvements in anti-glare, light uniformity, quantum dot excitation uniformity, and light utilization efficiency through the optical design of a microstructured light-uniforming film and a multilayer directional blue light reflective film. It improves the uniformity of emitted light from the Mini-LED backlight module, suppressing glare and quantum dot excitation unevenness caused by direct blue light at small angles, while also meeting the requirements for ultra-thin backlight module design and low-cost production.
[0052] All equivalent changes made to the structure, shape, and principle of this application shall be covered within the scope of protection of this application.
Claims
1. A composite diffusion film for an anti-glare and uniform light quantum dot backlight module, characterized in that, The device includes a microstructured light-diffusing film layer and a multilayer directional blue light reflective film layer stacked together. The multilayer directional blue light reflective film layer is disposed on the light-emitting side of the microstructured light-diffusing film layer, and the side of the microstructured light-diffusing film layer away from the multilayer directional blue light reflective film layer is used to face the blue light source of the backlight module. The multilayer directional blue light reflective film layer is composed of alternating layers of high birefringence resin layer and low refractive index resin layer. The multilayer directional blue light reflective film layer has a reflectivity of greater than or equal to 90% for blue light in the 450nm-475nm wavelength band at an incident angle of 0°-40°, and a full-angle transmittance of greater than or equal to 92% for visible light in the 500nm-780nm wavelength band.
2. The anti-glare and uniform light quantum dot backlight module composite diffusion film according to claim 1, characterized in that: The number of stacked layers of the multilayer directional blue light reflective film is 100-300.
3. The anti-glare and uniform light quantum dot backlight module composite diffusion film according to claim 1, characterized in that: The high birefringence resin layer is made of PET or PEN, and the low refractive index resin layer is made of PMMA.
4. The anti-glare and uniform light quantum dot backlight module composite diffusion film according to claim 1, characterized in that: The surface of the microstructure uniform light film layer facing the multilayer directional blue light reflective film layer is provided with a periodically arranged array of microlenses. The microlenses are prism-shaped, and the length and width of the bottom surface of the microlenses are smaller than the size of the light-emitting surface of the blue light source of the backlight module.
5. The anti-glare and uniform light quantum dot backlight module composite diffusion film according to claim 4, characterized in that: The microlens has a bottom surface length and width of 50μm-100μm, a height of 5μm-25μm, a center-to-center distance of 5μm-10μm between adjacent microlenses, and a top angle of 145°.
6. The anti-glare and uniform light quantum dot backlight module composite diffusion film according to claim 1, characterized in that: The material of the microstructured light-uniforming film is optical-grade transparent resin, the refractive index of which is 1.42-1.56, and the uniformity of the emitted light of the microstructured light-uniforming film is greater than or equal to 94%.
7. The anti-glare and uniform light quantum dot backlight module composite diffusion film according to claim 1, characterized in that: The total thickness of the microstructured uniform light film and the multilayer directional blue light reflective film is less than or equal to 80 μm.
8. A method for preparing an anti-glare, uniform light-emitting quantum dot backlight module composite diffusion film according to any one of claims 1-7, characterized in that, Includes the following steps: S1. The high birefringence resin layer material and the low refractive index resin layer material are alternately stacked and cast, and after biaxial stretching, a multi-layer directional blue light reflective film layer is formed. S2. Optical grade transparent resin is hot-pressed to form a microstructured light-uniforming film layer with a microlens array on the surface. S3. The microstructure uniform light film layer and the multilayer directional blue light reflective film layer are bonded together with optical adhesive, so that the multilayer directional blue light reflective film layer is located on the light-emitting side of the microstructure uniform light film layer, thereby obtaining an anti-glare uniform light quantum dot backlight module composite diffusion film.
9. A backlight module, comprising a blue light source layer, a quantum dot film layer, and a composite diffusion film disposed between the blue light source layer and the quantum dot film layer, characterized in that, The composite diffusion film is an anti-glare and uniform light quantum dot backlight module composite diffusion film according to any one of claims 1-7, wherein the microstructure uniform light film layer is close to the blue light source layer, and the multilayer directional blue light reflective film layer is close to the quantum dot film layer.