Backlight module with U-shaped frame and yellow reflective film
By attaching a yellow reflective film to the blue LED backlight module, the white reflective film layer reflects and scatters light, while the yellow fluorescent resin layer absorbs and converts blue light, thus solving the problem of blue light leakage and improving the visual effect and light uniformity.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- DONGGUAN SANBAO MATERIAL TECH CO LTD
- Filing Date
- 2025-07-15
- Publication Date
- 2026-06-23
AI Technical Summary
Existing blue LED backlight modules are prone to blue light leakage at the lamp opening position, resulting in poor visual effect.
A yellow reflective film is attached above the blue LED and on the upper left side of the light guide plate. The yellow reflective film consists of a white reflective film layer and a yellow fluorescent resin layer. The white reflective film layer reflects scattered or unused light, while the yellow fluorescent resin layer absorbs blue light and is excited to produce yellow light, which is then mixed to form white light.
It effectively prevents blue light leakage, improves visual effects, and achieves uniform white light output.
Smart Images
Figure CN224399707U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of backlight module technology, and in particular to a backlight module with a U-shaped frame fitted with a yellow reflective film. Background Technology
[0002] Currently, LCD screens are widely used in monitors, tablets, and laptops. An LCD screen consists of an LCD panel and an LED backlight module, with the LED backlight module providing the light source for the LCD panel. LED backlight modules are primarily edge-lit LED backlight modules. These can be categorized into two main types based on the type of LED: the first type uses high color gamut white LEDs as the light source, mainly used in products with high display performance requirements, such as larger tablets and gaming laptops; the second type uses blue LEDs as the light source, mainly used in products with high eye protection requirements, such as mini tablets, children's tablets, and medical monitors.
[0003] like Figure 1 The diagram shows a cross-sectional view of the light guide plate of an LED backlight module using blue LEDs as a light source in the prior art. The backlight module includes a back plate 1, a U-shaped frame 2 at the left end of the back plate 1, an LED 3 installed inside the U-shaped frame 2, and a light guide plate 4 installed on the right side of the LED 3. The blue light emitted by the LED 3 can be uniformly guided out through the light guide plate 4. The upper side of the light guide plate 4 is the light-emitting surface, and a QD (Quantum Dot) film 5 is attached to the upper side of the light guide plate 4. The QD film 5 contains red and green quantum dots. When the blue light uniformly guided out from the light guide plate 4 passes through the QD film 5, the red and green quantum dots in the QD film 5 absorb the blue light and emit red and green light. The red and green light then mix with the blue light to form white light, which is then emitted upwards. A black and white reflective film or a white reflective film 6 is attached to the lower side of the upper end of the U-shaped frame 2. The black and white reflective film refers to a composite reflective film with a black film layer on the top and a white film layer on the bottom. The white reflective film refers to a reflective film with a single white film layer. The black and white reflective film or the white reflective film 6 is located above the ends of the LED 3 and the light guide plate 4, and can reflect some of the light emitted by the LED 3 to the light guide plate 4.
[0004] Because the white reflective film only reflects light, the black layer in the black-and-white reflective film only blocks light, and the white layer only reflects light, the black-and-white reflective film or the white reflective film 6 can only reflect blue light and cannot convert blue light into white light. Furthermore, since the LED is a blue LED, the light intensity at the light-incident end of the light guide plate 4 is relatively high. Therefore, some blue light will still leak out at the light-incident end of the light guide plate. When the human eye observes the LED backlight module at a wide viewing angle (E) near the lamp opening of LED 3, that is, when observing… Figure 1When the dotted circle is in the middle, blue light will leak out from the light source from a wide angle, which is not visually appealing. Utility Model Content
[0005] The technical problem to be solved by this utility model is to provide a backlight module with a U-shaped frame and a yellow reflective film, which addresses the shortcomings of the above-mentioned technology. The backlight module has a yellow reflective film attached above the LED and on the upper left side of the light guide plate. The yellow reflective film includes a white reflective film layer and a yellow fluorescent resin layer from top to bottom. The white reflective film layer can efficiently reflect scattered or unused light back. The yellow fluorescent resin layer can absorb blue light and generate yellow light. The yellow light then mixes with the blue light to form white light, thereby avoiding blue light leakage at the lamp opening position of the backlight module and improving the visual effect.
[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is: a backlight module with a U-shaped frame and a yellow reflective film, including a back plate, a blue LED, a light guide plate, a QD film, and a yellow reflective film. The left end of the back plate is connected to a U-shaped frame, and a blue LED is installed inside the U-shaped frame. The light guide plate is disposed on the upper side of the back plate and located to the right of the blue LED. The light emitted by the blue LED can be uniformly guided out through the light guide plate. The upper side of the light guide plate is the light-emitting surface, and the QD film is attached to the upper side of the light guide plate. The upper end of the U-shaped frame has a top edge strip. The left end of the yellow reflective film is attached to the lower side of the top edge strip of the U-shaped frame and located above the blue LED. The right end of the yellow reflective film is attached to the upper left side of the light-emitting surface of the light guide plate. The yellow reflective film includes a white reflective film layer and a yellow fluorescent resin layer from top to bottom.
[0007] In the above technical solution, a white high-reflectivity ink layer is coated on the lower side of the white reflective film layer. The yellow fluorescent resin layer comprises, from top to bottom, a first yellow fluorescent resin layer, a second yellow fluorescent resin layer, and a third yellow fluorescent resin layer. The first yellow fluorescent resin layer is coated on the lower side of the white high-reflectivity ink layer, the second yellow fluorescent resin layer is coated on the lower side of the first yellow fluorescent resin layer, and the third yellow fluorescent resin layer is coated on the lower side of the second yellow fluorescent resin layer. The thickness of the white reflective film layer is 25–300 μm, the thickness of the white high-reflectivity ink layer is 2–5 μm, and the thicknesses of the first, second, and third yellow fluorescent resin layers are 2–6 μm, respectively. A diffusion particle layer with a thickness of 5–7 μm is further provided below the third yellow fluorescent resin layer. The diffusion particle layer is a PMMA acrylic particle layer.
[0008] In the above technical solution, the U-shaped frame includes a side strip, which is vertically connected to the left end of the back panel and is formed by bending upward from the left end of the back panel. The top strip is horizontally connected to the upper end of the side strip and is formed by bending to the right from the upper end of the side strip. The top strip is parallel to the back panel.
[0009] In the above technical solution, a light strip FPC is attached to the upper left end of the back plate, and a row of blue LEDs is welded to the upper left end of the light strip FPC. The lower left side of the light guide plate and the upper right side of the light strip FPC are bonded to each other with double-sided adhesive.
[0010] In the above technical solution, the QD film includes a first PET high-permeability film layer and a second PET high-permeability film layer, with red and green quantum dot layers sandwiched between the first PET high-permeability film layer and the second PET high-permeability film layer.
[0011] In the above technical solution, a reflective film is attached to the lower side of the light guide plate, a diffusion film is attached to the upper side of the QD film, a lower brightness enhancement film is attached to the upper side of the diffusion film, and an upper brightness enhancement film is attached to the upper side of the lower brightness enhancement film.
[0012] In the above technical solution, the backlight module with yellow reflective film attached to the U-shaped frame also includes liquid crystal glass. The left end of the liquid crystal glass is attached to the top edge strip of the U-shaped frame. A lower polarizer is attached to the lower side of the liquid crystal glass, and an upper polarizer is attached to the upper side of the liquid crystal glass. An OCA optical adhesive layer is provided on the upper side of the upper polarizer, and a high-transparency glass protective cover is provided on the upper side of the OCA optical adhesive layer. The upper polarizer and the high-transparency glass protective cover are bonded together by the OCA optical adhesive layer.
[0013] The beneficial effects of this utility model are as follows: The backlight module of this utility model has a yellow reflective film attached above the blue LED and on the upper left side of the light guide plate. The left end of the yellow reflective film is attached to the lower side of the top edge strip of the U-shaped frame and above the blue LED, while the right end is attached to the upper left side of the light guide plate. The yellow reflective film, from top to bottom, includes a white reflective film layer and a yellow fluorescent resin layer. Firstly, the white reflective film layer can efficiently reflect scattered or unused light back. Secondly, the yellow fluorescent resin layer can absorb blue light and generate yellow light, which then mixes with the blue light to form white light, thereby preventing blue light leakage at the lamp opening position of the backlight module and resulting in a good visual effect. Attached Figure Description
[0014] Figure 1 This is a cross-sectional view of the light-incident end of the light guide plate in a side-lit blue LED backlight module in the prior art.
[0015] Figure 2 This is a preferred embodiment of the backlight module of this utility model.
[0016] Figure 3 This is a schematic diagram of a preferred embodiment of the backlight module of this utility model.
[0017] Figure 4This is a longitudinal sectional view of a preferred embodiment of the backlight module of this utility model.
[0018] Figure 5 for Figure 4 A magnified view of part A in the middle.
[0019] Figure 6 This is a diagram showing the layered structure of the yellow reflective film in the backlight module of this utility model.
[0020] Figure 7 This is a preferred layer structure diagram of the yellow reflective film in the backlight module of this utility model.
[0021] Figure 8 This is a diagram showing the layered structure of the QD film in the backlight module of this utility model. Detailed Implementation
[0022] The structural and working principles of this utility model will be further described in detail below with reference to the accompanying drawings.
[0023] In the description of this utility model, it should be understood that the terms "upper", "lower", "left", "right", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the utility model.
[0024] like Figures 2-6As shown, this utility model is a backlight module with a U-shaped frame and a yellow reflective film, including a back plate 1, a blue LED 3, a light guide plate 4, a QD (Quantum Dot) film 5, and a yellow reflective film 7. The left end of the back plate 1 is connected to a U-shaped frame 2, and the blue LED 3 is installed inside the U-shaped frame 2. The light guide plate 4 is located on the upper side of the back plate 1 and to the right of the blue LED 3. The lower side of the light guide plate 4 is a reflective surface with a dotted pattern. The emitted light can be uniformly guided out through the dot matrix of the light guide plate 4. The upper side of the light guide plate 4 is the light-emitting surface, and a QD film 5 is attached to the upper side of the light guide plate 4. The upper end of the U-shaped frame 2 has a top edge strip 21. The left end of the yellow reflective film 7 is attached to the lower side of the top edge strip 21 of the U-shaped frame 2 and is located above the blue LED 3. The right end of the yellow reflective film 7 is attached to the upper left side of the light-emitting surface of the light guide plate 4. The yellow reflective film 7 includes a white reflective film layer 71 and a yellow fluorescent resin layer 72 from top to bottom. The blue LED 3 of this application is an InGaN (indium gallium nitride) based blue LED. The center wavelength range of the blue light is 450-465nm, and the peak wavelength is commonly between 452-455nm. The QD (Quantum Dot) film 5 contains red and green quantum dots. When blue light uniformly guided from the light guide plate 4 passes through the QD film 5, the red and green quantum dots in the QD film 5 absorb the blue light and emit red and green light. The red and green light then mix with the blue light to form white light, which is then emitted upwards. The white reflective film layer 71 of this invention can efficiently reflect scattered or unused light back. The yellow fluorescent resin layer 72 of this invention can absorb blue light and generate yellow light, which then mixes with the blue light to form white light, thereby preventing blue light leakage at the lamp opening position of the backlight module and providing a good visual effect.
[0025] like Figure 8 As shown, the QD film 5 of this application includes a first PET high-transparency film layer 51 and a second PET high-transparency film layer 52, with red and green quantum dot layers 53 sandwiched between the first PET high-transparency film layer 51 and the second PET high-transparency film layer 52. The QD film absorbs blue light and emits red / green light, and its absorption characteristics depend on the material and structure of the quantum dots: Cd-based quantum dots (such as CdSe) can efficiently absorb blue light in the 450-480nm range. For example, CdSe / ZnS core-shell QDs can achieve an absorption rate of over 90% at 450nm. Cadmium-free quantum dots (such as InP and perovskite): For example, InP QDs absorb blue light <480nm, and perovskite quantum dots (such as CsPbBr3) absorb <520nm, but perovskite quantum dots need to be optimized to avoid residual absorption in the green light region. Wavelength matching strategies to improve blue light leakage: (1) Optimize the matching between the absorption spectrum of the QD film and the blue LED, and adjust the QD film size / composition: for example, reducing the size of the CdSe QD film can cause its absorption edge to shift to blue, enhancing the absorption near 450nm. Mix QD with phosphor: add red phosphor with stronger blue absorption (such as K2SiF6:Mn).4 (2) Compensate for the weak absorption region of InP QD; (3) Narrow the blue LED spectrum by using DBR (distributed Bragg reflector) to filter out the components >470nm in the LED spectrum and reduce the bands not covered by the QD film; (4) Add the wavelength effect of yellow fluorescent resin. Yellow phosphor (such as YAG:Ce³⁺) can absorb 440~480nm blue light and emit 500~700nm broadband yellow light, effectively neutralizing the blue light leakage.
[0026] like Figure 7 As shown, the white reflective film layer 71 is coated with a white high-reflectivity ink layer 711 on its lower side. The yellow fluorescent resin layer 72, from top to bottom, includes a first yellow fluorescent resin layer 721, a second yellow fluorescent resin layer 722, and a third yellow fluorescent resin layer 723. The first yellow fluorescent resin layer 721 is coated on the lower side of the white high-reflectivity ink layer 711, the second yellow fluorescent resin layer 722 is coated on the lower side of the first yellow fluorescent resin layer 721, and the third yellow fluorescent resin layer 723 is coated on the lower side of the second yellow fluorescent resin layer 722. The reflectivity of the white reflective film layer 71 of this invention is typically 88%–90%, but after coating with the white high-reflectivity ink layer 711, the reflectivity of the white reflective film layer 71 can be increased to 95%–97%, and the white reflective film layer 71 can maintain a high reflectivity standard for a long time. The yellow fluorescent resin layer 72 of this invention is formed by sequentially coating a first yellow fluorescent resin layer 721, a second yellow fluorescent resin layer 722, and a third yellow fluorescent resin layer 723. The three-layer thin coating method can reduce brightness loss, make the coating more uniform and dense, and accurately control the proportion and concentration of yellow fluorescent resin in the yellow fluorescent resin layer 72, avoiding the problems of excessive or insufficient pink.
[0027] like Figure 7 As shown, the thickness of the white reflective film layer 71 is 25–300 μm, the thickness of the white high-reflectivity ink layer 711 is 2–5 μm, and the thicknesses of the first yellow fluorescent resin layer 721, the second yellow fluorescent resin layer 722, and the third yellow fluorescent resin layer 723 are 2–6 μm, respectively. This thickness range allows the white reflective film layer 71 and the yellow fluorescent resin layer 72 to achieve optimal light reflection.
[0028] like Figure 7 As shown, in a preferred embodiment of this invention, a diffusion particle layer 73 with a thickness of 5–7 μm is further provided below the third yellow fluorescent resin layer 723. Preferably, the diffusion particle layer 73 is a PMMA acrylic particle layer. The high-refractive-index diffusion particle layer 73 coated on the yellow fluorescent resin layer 72 further improves light utilization, allowing reflected light to be refracted, resulting in better light refraction and mixing uniformity, allowing more light to enter the light guide plate 4, and improving the brightness of the backlight module.
[0029] like Figures 3-5 As shown, the U-shaped frame 2 includes side strips 22, which are vertically connected to the upper left end of the back panel 1 and formed by bending upwards from the left end of the back panel 1. A top strip 21 is horizontally connected to the upper end of the side strips 22 and formed by bending to the right from the upper end of the side strips 22. The top strip 21 is parallel to the back panel 1. This bending method ensures the stability of the U-shaped frame 2.
[0030] like Figures 3-5 As shown, a light strip FPC 8 is attached to the upper left end of the back plate 1, and a row of blue LEDs 3 is welded to the upper left end of the light strip FPC 8. The lower left side of the light guide plate 4 is bonded to the upper right side of the light strip FPC 8 with double-sided adhesive, so that the left end of the light guide plate 4 can be tightly attached to the blue LEDs 3.
[0031] like Figures 3-5 As shown, a reflective film 9 is attached to the lower side of the light guide plate 4, which reflects the light leaking through the light guide plate 4 back, reducing light loss and increasing backlight brightness; a diffusion film 10 is attached to the upper side of the QD film 5, which makes the light more uniform through internal microstructures (such as scattering particles or imprinted structures), correcting the line light source or point light source output by the light guide plate 4 into a uniform surface light source, avoiding uneven local brightness; a lower brightness enhancement film 11 is attached to the upper side of the diffusion film 10, and an upper brightness enhancement film 12 is attached to the upper side of the lower brightness enhancement film 11.
[0032] like Figures 3-5 As shown, the backlight module with a yellow reflective film attached to the U-shaped frame also includes a liquid crystal glass 13. The left end of the liquid crystal glass 13 is attached to the top edge strip 21 of the U-shaped frame 2. A lower polarizer 14 is attached to the lower side of the liquid crystal glass 13, and an upper polarizer 15 is attached to the upper side of the liquid crystal glass 13. An OCA optical adhesive layer 16 is provided on the upper side of the upper polarizer 15, and a high-transparency glass protective cover plate 17 is provided on the upper side of the OCA optical adhesive layer 16. The upper polarizer 15 and the high-transparency glass protective cover plate 17 are bonded together by the OCA optical adhesive layer 16.
[0033] The above description is merely a preferred embodiment of this utility model. Any minor modifications, equivalent changes, and alterations made to the above embodiments based on the technical solution of this utility model shall fall within the scope of the technical solution of this utility model.
Claims
1. A backlight module with a U-shaped frame and a yellow reflective film, characterized in that: The device includes a backplate, a blue LED, a light guide plate, a QD film, and a yellow reflective film. The left end of the backplate is connected to a U-shaped frame, and the blue LED is installed inside the U-shaped frame. The light guide plate is located on the upper part of the backplate and to the right of the blue LED. The light emitted by the blue LED can be uniformly guided out through the light guide plate. The upper side of the light guide plate is the light-emitting surface, and the QD film is attached to the upper side of the light guide plate. The upper end of the U-shaped frame has a top edge strip. The left end of the yellow reflective film is attached to the lower side of the top edge strip of the U-shaped frame and above the blue LED. The right end of the yellow reflective film is attached to the upper left side of the light-emitting surface of the light guide plate. The yellow reflective film consists of a white reflective film layer and a yellow fluorescent resin layer from top to bottom.
2. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 1, characterized in that: The white reflective film layer is coated with a white high-reflectivity ink layer on its lower side. The yellow fluorescent resin layer includes a first yellow fluorescent resin layer, a second yellow fluorescent resin layer and a third yellow fluorescent resin layer from top to bottom. The first yellow fluorescent resin layer is coated on the lower side of the white high-reflectivity ink layer, the second yellow fluorescent resin layer is coated on the lower side of the first yellow fluorescent resin layer, and the third yellow fluorescent resin layer is coated on the lower side of the second yellow fluorescent resin layer.
3. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 2, characterized in that: The thickness of the white reflective film layer is 25–300 μm, the thickness of the white high-reflective ink layer is 2–5 μm, and the thicknesses of the first yellow fluorescent resin layer, the second yellow fluorescent resin layer, and the third yellow fluorescent resin layer are 2–6 μm, respectively.
4. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 2, characterized in that: Below the third yellow fluorescent resin layer, there is also a diffusion particle layer with a thickness of 5-7 μm.
5. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 2, characterized in that: The diffused particle layer is a PMMA acrylic particle layer.
6. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 1, characterized in that: The U-shaped frame includes a side strip, which is vertically connected to the upper left end of the back panel and is formed by bending upward from the left end of the back panel. The top strip is horizontally connected to the upper end of the side strip and is formed by bending to the right from the upper end of the side strip. The top strip is parallel to the back panel.
7. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 1, characterized in that: A light strip FPC is attached to the upper left end of the back plate, and a row of blue LEDs is welded to the upper left end of the light strip FPC. The lower left side of the light guide plate is bonded to the upper right side of the light strip FPC with double-sided adhesive.
8. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 1, characterized in that: The QD film includes a first PET high-permeability film layer and a second PET high-permeability film layer, with red and green quantum dot layers sandwiched between the first PET high-permeability film layer and the second PET high-permeability film layer.
9. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 1, characterized in that: A reflective film is attached to the lower side of the light guide plate, a diffusion film is attached to the upper side of the QD film, a lower brightness enhancement film is attached to the upper side of the diffusion film, and an upper brightness enhancement film is attached to the upper side of the lower brightness enhancement film.
10. The backlight module with a yellow reflective film attached to a U-shaped frame according to claim 1, characterized in that: It also includes liquid crystal glass, the left end of which is attached to the top edge strip of the U-shaped frame, a lower polarizer is attached to the lower side of the liquid crystal glass, an upper polarizer is attached to the upper side of the liquid crystal glass, an OCA optical adhesive layer is provided on the upper side of the upper polarizer, and a high-transparency glass protective cover is provided on the upper side of the OCA optical adhesive layer. The upper polarizer and the high-transparency glass protective cover are bonded together by the OCA optical adhesive layer.