RGB Mini LED backlight module based on double electrogenerated QD films, using method and manufacturing method

Abstract

The invention discloses an RGB Mini LED backlight module based on double electroluminescent QD films, a using method and a manufacturing method, the backlight module comprises a substrate, LED chips, the electroluminescent QD films, a diffusion plate and a brightness enhancement film, the LED chips are arranged on the substrate, the electroluminescent QD films are arranged above the LED chips, display units of the electroluminescent QD films are arranged corresponding to the LED chips, the diffusion plate is arranged above the electroluminescent QD films, and the brightness enhancement film is arranged on the substrate. And the bright enhancement film is arranged above the diffusion plate. According to the invention, only a composite backlight framework of the RGB Mini LED and the electro-generated QD film is adopted, and a traditional three-color Mini LED array is replaced. According to the invention, RGB Mini LED backlight with overall high color gamut, wide temperature range stability and independent and accurate color control can be realized, color point correction of spectrum synthesis is carried out from a backlight source, accurate and adjustable spectrum of the backlight source can be realized, and the problems of brightness loss, low efficiency and color consistency caused by panel adjustment in a traditional scheme are fundamentally solved.

Description

TECHNICAL FIELD

[0001] The application discloses an LED backlight module, in particular to a RGB Mini LED backlight module based on a double electro-QD film, a use method and a manufacturing method, and belongs to the technical field of display device backlight modules. BACKGROUND

[0002] With the deep evolution of display technology towards "high color accuracy, high consistency and high light efficiency", Mini LED backlight with independent partition light control capability has become the core solution of high-end televisions, professional displays and vehicle screens. The current industry focuses on two points for the core demands of such backlight: first, color point control needs strong cross-panel adaptation capability to compatible different batches of color film optical tolerances and improve production flexibility; second, color output needs to remain highly stable within the life of the whole machine to meet the stringent reliability requirements of professional scenarios such as medical diagnosis and content creation.

[0003] However, the existing mainstream technical solutions face two fundamental contradictions: first, at the light source level, the traditional RGB three-color Mini LED architecture for realizing high color gamut has different chip materials, driving characteristics and aging curves for red, green and blue, which not only makes the circuit design complex, but also causes irreversible color deviation due to inconsistent light decay of each color chip in long-term use, making it difficult to guarantee the color accuracy at the end of life. Second, at the calibration strategy level, the industry generally adopts a passive compensation mode of "fixed spectrum backlight + adjusting panel transmittance", which forces the liquid crystal panel to deviate from the optimal working point, resulting in a loss of overall light efficiency of more than 20%, and the calibration accuracy is limited by the superimposed influence of the fluctuations of "light source-optical film-liquid crystal panel" multiple supply chains, making it difficult to control the consistency of color points in mass production, and the yield and performance are difficult to be compatible.

[0004] The prior art generally uses a fixed spectrum backlight (such as a blue light LED + phosphor or static white light Mini LED), and compensates for the white point (white point: refers to the color point corresponding to the full white picture of the display device. It defines the color balance reference of the whole screen, and is the reference white color of all color mixing.) by adjusting the panel driving voltage. Although the backlight design is simplified, this method has significant drawbacks - when the panel deviates from the optimal transmittance operating point to match the target color point, it will directly cause overall brightness loss and energy efficiency decline. At the same time, the production process is complicated, and each module must be calibrated after assembly, which cannot achieve decoupled production of the panel and backlight (decoupled production: refers to separating and independent two or more production or test links that must be closely connected in the same time, same place and fixed order in the product manufacturing process.), and cannot compensate for the spectral fluctuations of the backlight components. This results in a high dependence of product color point consistency on the limited compensation ability of the panel, making it difficult to meet the stringent requirements of high-end displays for accurate color and production yield, and also unable to support dynamic color management functions. Therefore, there is currently a lack of a backlight solution that can actively and accurately regulate the output spectrum from the source, achieving high color point consistency, high optical efficiency and dynamic color capability. SUMMARY

[0005] In view of the brightness loss and low efficiency caused by adjusting the panel compensation color point in the prior art mentioned above, the present application provides a RGB Mini LED backlight module based on double electro QD film, a method of use and a manufacturing method, which is a new display backlight solution that actively regulates the spectrum from the backlight source and achieves high-precision color point consistency. The application adopts a composite light source architecture of "blue Mini LED array + voltage-adjustable double electro QD film", directly and independently regulates the spectral output of the electro QD film through voltage, and thus realizes the precise and dynamic synthesis of the final outgoing white light spectrum at the source of the backlight. The present application fundamentally replaces the traditional multi-color chip light mixing and passive compensation scheme at the panel end, aiming to solve the coordinated problems of accurate color point control, cross-panel adaptation, long-term color stability and light efficiency optimization at one time, and provides a core backlight solution for the next generation of high-end displays.

[0006] The technical scheme adopted by the present application to solve its technical problems is: a RGB Mini LED backlight module based on double electro QD film, the backlight module comprising a substrate, an LED chip, an electro QD film, a diffusion plate and a brightness enhancement film, the LED chip being arranged on the substrate, the electro QD film being arranged above the LED chip, the display unit of the electro QD film being arranged correspondingly to the LED chip, the diffusion plate being arranged above the electro QD film, and the brightness enhancement film being arranged above the diffusion plate.

[0007] A color point correction method for realizing spectrum synthesis of the RGB Mini LED backlight module based on the above-mentioned double-electro QD film, the color point correction method comprising the following steps: First, only the blue light LED is turned on, and the blue light emitted thereby is irradiated to the electro QD film in an unpowered state. The quantum dots generate photoluminescence under the excitation of the blue light, emit red light and green light, and mix with the partially transmitted blue light to form initial white light. Subsequently, a driving voltage is applied to the electro QD film to make it enter an electro luminescence state, and the intensity of the green light and / or red light emitted thereby is accurately controlled by adjusting the voltage value applied to the electro QD film, so as to adjust the mixing ratio of the three colors of light in the white light, and finally realize the required white balance.

[0008] A manufacturing method of the RGB Mini LED backlight module based on the double-electro QD film, the manufacturing method comprising the following steps: Step 1, LED lamp plate manufacturing: welding LED chips on a substrate; Step 2, lamp bead arrangement: encapsulating in a full-face dispensing manner on the surface of the substrate, and alternately arranging each LED chip and a reflection cover; Step 3, superimposing double-electro QD film: the first electro QD film is attached to the surface of the LED chip array through optical glue, so as to ensure that the micro-zones of the electro QD film are accurately aligned with the LED chips, and the second electro QD film is attached to the surface of the first electro QD film through optical glue, and the electrode leads of the two layers of films are respectively connected to the control panel through the control interface; Step 4, module assembly: connecting the control panel with the LED driving circuit and the electrode of the electro QD film; Step 5, backlight assembly: sequentially stacking a diffusion plate, a first light enhancement film and a second light enhancement film according to the design, and thus the backlight assembly is completed.

[0009] The technical solution further comprises: The LED chips are regularly distributed on the substrate.

[0010] The LED chip light emitting unit is provided with a reflection cover around or between adjacent LED chip light emitting units.

[0011] The electro QD film is designed in micro-zones, and the length of each micro-zone is the same as the pitch value of the LED chip.

[0012] The electro QD film is provided with two layers, i.e., a first electro QD film and a second electro QD film. The first electro QD film is a red electro QD film, and the second electro QD film is a green electro QD film. The first electro QD film is arranged above the LED chip, and the second electro QD film is arranged above the first electro QD film.

[0013] The second electro-QD film includes a QD film substrate, a bottom electrode, a hole injection layer, a hole transport layer, a quantum dot light-emitting layer, an electron transport layer, and a top electrode. The QD film substrate, bottom electrode, hole injection layer, hole transport layer, quantum dot light-emitting layer, electron transport layer, and top electrode are stacked sequentially from bottom to top. The structure of the first electro-QD film is the same as that of the second electro-QD film.

[0014] The first electro-QD film, the second electro-QD film, and the LED chip are electrically connected to the control board via a control interface.

[0015] The brightness enhancement film has two layers, namely a first brightness enhancement film and a second brightness enhancement film, which are stacked together.

[0016] The beneficial effects of this invention are as follows: This invention adopts a precise design of dual electroluminescent QD film layering, combined with a three-color synergistic driving mechanism of "electroluminescence + photoluminescence", using a blue Mini LED as the blue light source, and red and green electroluminescent QD films as independent electroluminescent units for red and green light respectively. The current ratio of the three is dynamically adjusted by the main control IC, and with the help of spectral feedback and temperature compensation, precise mixing of the RGB full color gamut is achieved.

[0017] This invention employs a composite backlight architecture of RGB Mini LED + electroluminescent QD film to replace the traditional three-color Mini LED array, achieving a high color gamut compatible solution. This invention achieves overall high color gamut, wide temperature range stability, and independent, precise color control in RGB Mini LED backlighting. The color point correction method, which synthesizes the spectrum from the backlight head, enables precise adjustment of the backlight head spectrum, fundamentally solving the problems of brightness loss, low efficiency, and color consistency caused by panel calibration in traditional solutions.

[0018] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0019] Figure 1 This is a schematic diagram of the interlayer structure of the present invention.

[0020] Figure 2 This is a schematic diagram of the micro-partition design structure of the electro-induced QD film of the present invention.

[0021] Figure 3 This is a schematic diagram of the structure of a single LED display unit in this invention.

[0022] Figure 4 This is a schematic diagram of the microstructure of the electro-induced QD membrane in this invention.

[0023] In the figure, 1 is a substrate, 2 is an LED chip, 3 is a reflector, 4 is a first electro致QD film, 5 is a second electro致QD film, 6 is a diffusion plate, 7 is a first brightness enhancement film, 8 is a second brightness enhancement film, 9 is a control board, 10 is a control interface, 11 is a top electrode, 12 is an electron transport layer, 13 is a quantum dot light-emitting layer, 14 is a hole transport layer, 15 is a hole injection layer, 16 is a bottom electrode, and 17 is a QD film substrate. Specific implementation mode

[0024] This embodiment is the preferred implementation mode of the present invention. All other devices with the same or similar principles and basic structures as this embodiment are within the protection scope of the present invention.

[0025] Please refer to the attached Figure 1 to the attached Figure 4 This invention mainly protects an RGB Mini LED backlight module based on a dual electro致QD film. The electro致QD film is a functional film with quantum dots as the core material, which can achieve light emission or optical property changes through external electric field regulation, and can empower new display, intelligent dimming and other scenarios. The backlight module mainly includes a substrate 1, an LED chip 2, an electro致QD film, a diffusion plate 6 and a brightness enhancement film 7. The LED chip 2 is arranged on the substrate 1, and the electro致QD film is arranged above the LED chip 2. The display units of the electro致QD film are arranged corresponding to the LED chip 2, that is, the display units of each group of electro致QD films correspond to a group of LED chip 2 display units, or the display units of multiple groups of electro致QD films correspond to a group of LED chip 2 display units, or the display units of a group of electro致QD films correspond to multiple groups of LED chip 2 display units. The diffusion plate 6 is arranged above the electro致QD film, and the brightness enhancement film is arranged above the diffusion plate 6.

[0026] In this embodiment, the LED chips 2 are regularly distributed on the substrate 1. Preferably, the LED chips 2 are arranged in a matrix on the substrate 1. Specifically, when implemented, the LED chips 2 can also be arranged in a staggered manner on the substrate 1, or called a "pin" shape distribution, that is, one LED chip 2 light-emitting unit is arranged at the middle position between two LED chip 2 light-emitting units in the adjacent row.

[0027] In this embodiment, the LED chips 2 use blue LEDs. Reflectors 3 are arranged around the light-emitting units of the LED chips 2, which can be used to reflect the light emitted by the LED chips 2 to the surrounding areas to enhance the light intensity of the light-emitting surface. Specifically, when implemented, the reflectors 3 can also be arranged between adjacent LED chip 2 light-emitting units.

[0028] In this embodiment, the LED chip 2 is a Mini LED chip. Each group of Mini LED chips usually contains one Mini LED. In specific implementation, it may also contain multiple Mini LEDs. The portion inside the center of each group of Mini LED chips along with the surrounding reflector 3 is defined as a Pitch. The electro-QD film adopts a micro-segment design. The length of each segment is the same as the pitch value of the Mini LED chip. That is, it is preferred that each micro-segment of the electro-QD film corresponds to a group of Mini LED chips.

[0029] In this embodiment, the electroluminescent QD film has two layers, defined as a first electroluminescent QD film 4 and a second electroluminescent QD film 5. The first electroluminescent QD film 4 is a red electroluminescent QD film, and the second electroluminescent QD film 5 is a green electroluminescent QD film. The first electroluminescent QD film 4 is disposed above the LED chip 2, and the second electroluminescent QD film 5 is disposed above the first electroluminescent QD film 4. In a specific implementation, the first electroluminescent QD film 4 can also be a green electroluminescent QD film, and the second electroluminescent QD film 5 can be a red electroluminescent QD film. In a specific implementation, the electroluminescent QD film can also be a single layer, with one layer being a red or green electroluminescent QD film, and the other color being implemented using the LED chip.

[0030] In this embodiment, the structure of the second electroluminescent QD film 5 is described as an example. The main structure of the second electroluminescent QD film 5 includes a QD film substrate 17, a bottom electrode 16, a hole injection layer 15, a hole transport layer 14, a quantum dot light-emitting layer 13, an electron transport layer 12, and a top electrode 11. The QD film substrate 17, bottom electrode 16, hole injection layer 15, hole transport layer 14, quantum dot light-emitting layer 13, electron transport layer 12, and top electrode 11 are stacked sequentially from bottom to top. The QD film substrate 17 is the supporting structure of the second electroluminescent QD film 5 and is made of Al (aluminum foil) or Glass (glass, preferably glass in this embodiment). The bottom electrode 16 is made of ITO / MoO3 / NiOx material, and the hole injection layer 15 is made of PE. FOT: PSS, which has high conductivity, good hole transport capability, transparency and solution processability, is used as a hole injection layer (HIL) in this embodiment. Hole transport layer 14 is made of PVK, which is a typical organic hole transport material. The carbazole group in the molecular chain has strong hole transport capability and is used as a hole transport layer (HTL) in this embodiment. Quantum dot emitting layer 13 is made of CdSe. In this embodiment, the emission color of quantum dots can be achieved by controlling their size. By controlling the size of the CdSe core, the photon wavelength is fixed at 525nm (green light) and the half-width is only 30nm. The color purity is significantly better than that of phosphor (half-width > 50nm). Electron transport layer 12 is made of ZnO and top electrode 11 is made of ITO.

[0031] The luminescence process of electroluminescent QD films is based on "carrier injection-transport-radiative recombination", as detailed below (taking a green electroluminescent QD film as an example): (1) Carrier injection: Holes are injected into the bottom electrode 16 (e.g., ITO / MoO3 / NiOx), and the holes migrate to the quantum dot emission layer 13 (CdSe QD) via the hole injection layer 15 and the hole transport layer 14 (PEDOT: PSS, PVK); electrons are injected into the top electrode 11 (ITO), and the electrons migrate to the quantum dot emission layer 13 (CdSe QD) via the electron transport layer 12 (ZnO).

[0032] (2) Carrier capture and exciton formation: When electrons and holes meet in the CdSe quantum dot luminescent layer 13, they combine to form excitons (a type of electron-hole bound state).

[0033] (3) Radiative recombination luminescence: When an exciton is in an excited state, it will release energy in the form of a photon when it transitions from the excited state back to the ground state. The luminescence color of quantum dots can be achieved by controlling their size. By controlling the size of the CdSe core, the photon wavelength can be fixed at 525nm (green light) and the half-width is only 30nm. The color purity is significantly better than that of phosphors (half-width > 50nm).

[0034] The structure of the first electroluminescent QD film 4 is the same as that of the second electroluminescent QD film 5. The only difference is that the CdSe QD material in the quantum dot light-emitting layer 13 of the second electroluminescent QD film 5 is replaced with InP QD material. The light emission mechanism of the red electroluminescent QD film is the same as that of the green electroluminescent QD film. By adjusting the InP core size, the emission wavelength is fixed at 625nm (red light).

[0035] The first electro-QD film 4, the second electro-QD film 5, and the LED chip 2 are electrically connected to the control board 9 through the control interface 10. The main control IC on the control board 9 independently controls the "red film current, green film current, and Mini LED current" to achieve arbitrary mixing of the three primary colors.

[0036] This invention also protects a color point (color point: on a chromaticity diagram, a coordinate (x, y) represents the color attribute (hue, saturation) of a color, without brightness information, and can be used to describe any color) correction method for spectral synthesis from a backlight head. Its basic working steps are as follows: First, only the blue LED is turned on, allowing its emitted blue light to illuminate an electroluminescent QD film in a non-energized state. At this time, the quantum dots are excited by the blue light, producing photoluminescence, emitting red and green light, which mixes with some of the transmitted blue light to form initial white light. Subsequently, a driving voltage is applied to the electroluminescent QD film, causing it to enter an electroluminescent (photoluminescence: the physical phenomenon where quantum dots absorb external light energy, are excited, and emit light of a specific color) state. By adjusting this voltage value, the intensity of the emitted green and / or red light is precisely controlled, thereby adjusting the mixing ratio of the three colors in the white light, ultimately achieving the desired white balance.

[0037] In this embodiment, the brightness enhancement film (BEF) is used to enhance the brightness of the LED. The emitted scattered light is "converged" into parallel light in the forward direction (perpendicular to the screen direction), thereby improving the brightness of the front of the screen and reducing light waste to the sides and back. The brightness enhancement film has two layers: a first brightness enhancement film 7 and a second brightness enhancement film 8, which are stacked together. The microprism structure in the first brightness enhancement film 7 has its prisms oriented "vertically" (along the vertical direction of the screen), converging the light scattered from the left and right to the "front and back forward direction," thus solving the problem of light waste in the left and right directions. The microprism structure in the second brightness enhancement film 8 has its prisms oriented "horizontally" (along the horizontal direction of the screen), converging the light scattered from the top and bottom to the "front and back forward direction," thus solving the problem of light waste in the top and bottom directions. Alternatively, the microprism structure in the first brightness enhancement film 7 has its prisms oriented "horizontally" (along the horizontal direction of the screen), converging the light scattered from the top and bottom to the "front and back forward direction," thus solving the problem of light waste in the top and bottom directions; the microprism structure in the second brightness enhancement film 8 has its prisms oriented "vertically" (along the vertical direction of the screen), converging the light scattered from the left and right to the "front and back forward direction," thus solving the problem of light waste in the left and right directions.

[0038] This invention also protects a method for manufacturing an RGB Mini LED backlight module based on dual electroluminescent QD films, comprising the following steps: Step 1: Fabricate the LED light board: Solder the LED chips 2 onto the substrate 1 (PCB, aluminum, glass or other substrates); Step 2, LED chip arrangement: The entire surface of substrate 1 is encapsulated by applying adhesive to the substrate 1, with each LED chip 2 and reflector 3 arranged alternately. Step 3: Stacking dual electroluminescent QD films: The first electroluminescent QD film 4 (red) is bonded to the surface of the Mini LED chip 2 array with optical adhesive to ensure that the micro-partitions of the electroluminescent QD film are precisely aligned with the LED chip 2. The second electroluminescent QD film 5 (green) is bonded to the surface of the first electroluminescent QD film 4 (red) with optical adhesive of the same specification. The electrode leads of the two films are respectively connected to the control module drive interface on the control board 9 through the control interface 10. Step 4, Module Assembly: The control board 9 is connected to the Mini LED driving circuit and QD film electrode via FPC cable (in this embodiment, i.e., control interface 10) to complete the overall assembly; Step 5: Backlight assembly: Stack the diffuser plate 6, the first brightness enhancement film 7, and the second brightness enhancement film 8 in sequence according to the design. The backlight assembly is now complete.

[0039] This invention employs a precise design of dual electroluminescent QD films in layers, combined with a three-color synergistic driving mechanism of "electroluminescence + photoluminescence". It uses a blue Mini LED as the blue light source, and red and green electroluminescent QD films as independent electroluminescent units for red and green light, respectively. The current ratio of the three is dynamically adjusted by the main control IC, and with the help of spectral feedback and temperature compensation, precise mixing of the RGB full color gamut is achieved.

[0040] This invention uses only a single-color blue Mini LED combined with dual electroluminescent QD films to replace the traditional three-color Mini LED array, achieving a high color gamut compatible solution. This invention achieves overall high color gamut, wide temperature range stability, and independent, precise color control in RGB MiniLED backlighting.

Claims

1. An RGB Mini LED backlight module based on dual electroluminescent QD films, characterized in that: The backlight module includes a substrate (1), an LED chip (2), an electro-QD film, a diffuser plate (6), and a brightness enhancement film (7). The LED chip (2) is disposed on the substrate (1), the electro-QD film is disposed above the LED chip (2), the display unit of the electro-QD film is disposed corresponding to the LED chip (2), the diffuser plate (6) is disposed above the electro-QD film, and the brightness enhancement film is disposed above the diffuser plate (6).

2. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 1, characterized in that: The LED chips (2) are regularly distributed on the substrate (1).

3. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 1, characterized in that: A reflector (3) is provided around the LED chip (2) light-emitting unit or between adjacent LED chip (2) light-emitting units.

4. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 1, characterized in that: The electro-QD film adopts a micro-partition design, and the length of each partition is the same as the pitch value of the LED chip (2).

5. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 1, characterized in that: The electro-QD film has two layers, namely a first electro-QD film (4) and a second electro-QD film (5). The first electro-QD film (4) is a red electro-QD film, and the second electro-QD film (5) is a green electro-QD film. The first electro-QD film (4) is disposed above the LED chip (2), and the second electro-QD film (5) is disposed above the first electro-QD film (4).

6. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 5, characterized in that: The second electro-induced QD film (5) includes a QD film substrate (17), a bottom electrode (16), a hole injection layer (15), a hole transport layer (14), a quantum dot light-emitting layer (13), an electron transport layer (12), and a top electrode (11). The QD film substrate (17), bottom electrode (16), hole injection layer (15), hole transport layer (14), quantum dot light-emitting layer (13), electron transport layer (12), and top electrode (11) are stacked sequentially from bottom to top. The structure of the first electro-induced QD film (4) is the same as that of the second electro-induced QD film (5).

7. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 5, characterized in that: The first electro-QD film (4), the second electro-QD film (5), and the LED chip (2) are electrically connected to the control board (9) through the control interface (10).

8. The RGB Mini LED backlight module based on dual electroluminescent QD films according to claim 5, characterized in that: The brightness enhancement film has two layers, namely a first brightness enhancement film (7) and a second brightness enhancement film (8), which are stacked together.

9. A color point correction method for spectral synthesis using an RGB Mini LED backlight module based on a dual electro-QD film as described in any one of claims 1 to 8, characterized in that: The color point correction method includes the following steps: First, only the blue LED is turned on, so that the blue light emitted by it shines on the electroluminescent QD film in the unpowered state. The quantum dots are excited by the blue light and produce photoluminescence, emitting red and green light, which mixes with some of the transmitted blue light to form the initial white light. Subsequently, a driving voltage is applied to the electroluminescent QD film to put it into an electroluminescent state. The intensity of the emitted green and / or red light is precisely controlled by adjusting the voltage applied to the electroluminescent QD film, thereby adjusting the mixing ratio of the three colors in the white light and ultimately achieving the desired white balance.

10. A method for manufacturing an RGB Mini LED backlight module based on a dual electroluminescent QD film, characterized in that: The manufacturing method includes the following steps: Step 1: Make LED light board: Solder LED chips (2) onto substrate (1); Step 2, LED arrangement: The entire surface of the substrate (1) is encapsulated by applying adhesive, and each LED chip (2) is arranged alternately with the reflector (3); Step 3: Stacking dual electro-QD films: The first electro-QD film (4) is bonded to the surface of the LED chip (2) array with optical adhesive to ensure that the micro-partitions of the electro-QD film are precisely aligned with the LED chip (2). The second electro-QD film (5) is bonded to the surface of the first electro-QD film (4) with optical adhesive. The electrode leads of the two films are connected to the control board (9) through the control interface (10). Step 4, Module Assembly: Connect the control board (9) to the LED driver circuit and the electro-QD film electrode; Step 5: Backlight assembly: Stack the diffuser plate (6), the first brightness enhancement film (7), and the second brightness enhancement film (8) in sequence according to the design. The backlight assembly is now complete.

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