A dual-electric QD film-based RGB mini LED backlight module

Abstract

The utility model discloses a kind of RGB Mini LED backlight module based on double electro QD film, backlight module includes substrate, LED chip, electro QD film, diffusion plate and light enhancement film, LED chip is set on substrate, electro QD film is set above LED chip, display unit of electro QD film is correspondingly set with LED chip, diffusion plate is set above electro QD film, light enhancement film is set above diffusion plate.The utility model only uses the composite backlight architecture of RGB Mini LED+electro QD film, replaces traditional three-color Mini LED array.The utility model can realize whole high color gamut, wide temperature range stability, independent accurate color control RGB Mini LED backlight, from the color point correction of spectrum synthesis of backlight source head, can realize backlight source head spectrum accurate adjustable, fundamentally solve the luminance loss, low efficiency and color consistency problem caused by panel adjustment of traditional scheme.

Description

Technical Field

[0001] This utility model discloses an LED backlight module, particularly an RGB Mini LED backlight module based on a dual electroluminescent QD film, belonging to the technical field of display device backlight module. Background Technology

[0002] As display technology evolves towards higher color accuracy, higher consistency, and higher luminous efficiency, Mini LED backlighting with independent local dimming capabilities has become a core solution for high-end TVs, professional monitors, and automotive screens. Currently, the industry's core demands for this type of backlighting focus on two points: first, color point control must have strong cross-panel adaptability to accommodate the optical tolerances of different batches of color filters and improve production flexibility; second, color output must remain highly stable throughout the entire lifespan of the device to meet the stringent reliability requirements of professional scenarios such as medical diagnosis and content creation.

[0003] However, existing mainstream technologies face two fundamental contradictions: First, at the light source level, the traditional RGB three-color Mini LED architecture for achieving high color gamut is complex in circuit design due to the differences in red, green, and blue chip materials, driving characteristics, and aging curves. Furthermore, over long-term use, the inconsistent light decay of each color chip leads to irreversible color shifts, making it difficult to guarantee color accuracy at the end of its lifespan. Second, at the calibration strategy level, the industry generally adopts a passive compensation mode of "fixed spectrum backlight + adjusted panel transmittance." This method forces the LCD panel to deviate from its optimal operating point, resulting in an overall light efficiency loss of over 20%. Moreover, calibration accuracy is limited by the combined effects of fluctuations in multiple supply chains—from light source to optical film to LCD panel—making it difficult to control color consistency in mass production, and thus difficult to achieve both high yield and high performance.

[0004] Current technologies typically employ fixed-spectrum backlighting (such as blue LEDs + phosphors or static white Mini LEDs) and compensate for white point (white point: specifically refers to the color point corresponding to a completely white screen. It defines the color balance benchmark for the entire screen and is the reference white for mixing all colors) by adjusting the panel driving voltage. While simplifying backlight design, this method has significant drawbacks—when the panel deviates from its optimal transmittance operating point to match the target color point, it directly causes overall brightness loss and energy efficiency reduction. Simultaneously, it complicates the manufacturing process, requiring post-assembly calibration of each module, making it impossible to achieve decoupled production of the panel and backlight (decoupled production: refers to separating and independenting two or more production or testing stages that were originally closely connected at the same time, in the same place, and in a fixed sequence in the product manufacturing process), and it cannot compensate for the spectral fluctuations of the backlight components themselves. This results in the product's color point consistency being highly dependent on the limited compensation capabilities 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 precisely control the output spectrum from the source to achieve high color point consistency, high optical efficiency and dynamic color capability. Summary of the Invention

[0005] To address the aforementioned issues of brightness loss and low efficiency caused by adjusting panel compensation for color points in existing technologies, this invention provides an RGB Mini LED backlight module based on dual electroluminescent QD films. This novel backlight solution actively controls the spectrum from the backlight head, achieving high-precision color point consistency. It employs a composite light source architecture of "blue Mini LED array + voltage-adjustable dual electroluminescent QD films," directly and independently controlling the spectral output of the electroluminescent QD films via voltage, thereby achieving precise and dynamic synthesis of the final emitted white light spectrum at the backlight head. This invention fundamentally replaces the traditional multi-color chip mixing and passive panel-side compensation solution, aiming to solve the collaborative challenges of precise color point control, cross-panel adaptation, long-term color accuracy stability, and optimal luminous efficiency in one go, providing a core backlight solution for next-generation high-end displays.

[0006] The technical solution adopted by this utility model to solve its technical problem is: an RGB MiniLED backlight module based on dual electro-QD films. The backlight module includes a substrate, LED chips, electro-QD films, a diffuser plate, and a brightness enhancement film. The LED chips are disposed on the substrate, the electro-QD films are disposed above the LED chips, the display units of the electro-QD films are disposed corresponding to the LED chips, the diffuser plate is disposed above the electro-QD films, and the brightness enhancement film is disposed above the diffuser plate.

[0007] The technical solution adopted by this utility model to solve its technical problem further includes: The LED chips are regularly distributed on the substrate.

[0008] A reflector is provided around the LED chip light-emitting unit or between adjacent LED chip light-emitting units.

[0009] The electroluminescent QD film adopts a micro-segmentation design, with the length of each segment being the same as the pitch value of the LED chip.

[0010] The electro-QD film has two layers: a first electro-QD film and a second electro-QD film. The first electro-QD film is red, and the second electro-QD film is green. The first electro-QD film is positioned above the LED chip, and the second electro-QD film is positioned above the first electro-QD film.

[0011] 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.

[0012] 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.

[0013] The brightness enhancement film has two layers, namely a first brightness enhancement film and a second brightness enhancement film, which are stacked together.

[0014] The beneficial effects of this utility model are as follows: This utility model adopts a precise design of dual electroluminescent QD film layering, combined with the "electroluminescence + photoluminescence" three-color synergistic driving mechanism, using blue Mini LED as blue light source, and red and green electroluminescent QD films as independent red and green electroluminescent units 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.

[0015] 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 enables overall high color gamut, wide temperature range stability, and independent precise color control in RGB Mini LED backlighting. Color point correction through spectral synthesis at the backlight head allows for precise adjustment of the backlight head spectrum, fundamentally solving the brightness loss, low efficiency, and color consistency problems caused by panel calibration in traditional solutions.

[0016] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the interlayer structure of this utility model.

[0018] Figure 2 This is a schematic diagram of the micro-regional design structure of the electro-induced QD membrane of this utility model.

[0019] Figure 3 This is a schematic diagram of the structure of a single LED display unit in this utility model.

[0020] Figure 4 This is a schematic diagram of the microstructure of the electro-QD membrane in this utility model.

[0021] In the figure, 1-substrate, 2-LED chip, 3-reflector, 4-first electroluminescent QD film, 5-second electroluminescent QD film, 6-diffuser plate, 7-first brightness enhancement film, 8-second brightness enhancement film, 9-control board, 10-control interface, 11-top electrode, 12-electron transport layer, 13-quantum dot light-emitting layer, 14-hole transport layer, 15-hole injection layer, 16-bottom electrode, 17-QD film substrate. Detailed Implementation

[0022] This embodiment is a preferred embodiment of the present invention. All other embodiments that are the same as or similar to this embodiment in principle and basic structure are within the protection scope of the present invention.

[0023] Please refer to the appendix for details. Figure 1 To be continued Figure 4 This utility model mainly protects an RGB MiniLED backlight module based on dual electro-QD films. The electro-QD film is a functional thin film that uses quantum dots as the core material and achieves changes in light emission or optical properties through external electric field modulation. It can enable new display, intelligent dimming and other scenarios. The backlight module mainly includes a substrate 1, LED chips 2, electro-QD films, a diffuser plate 6 and a brightness enhancement film 7. The LED chips 2 are disposed on the substrate 1, and the electro-QD films are disposed above the LED chips 2. The display units of the electro-QD films are correspondingly disposed with the LED chips 2. That is, each set of electro-QD film display units corresponds to one set of LED chip 2 display units, or multiple sets of electro-QD film display units correspond to one set of LED chip 2 display units, or one set of electro-QD film display units corresponds to multiple sets of LED chip 2 display units. The diffuser plate 6 is disposed above the electro-QD films, and the brightness enhancement film is disposed above the diffuser plate 6.

[0024] In this embodiment, the LED chips 2 are regularly distributed on the substrate 1. Preferably, the LED chips 2 are distributed in a matrix pattern on the substrate 1. In specific implementation, the LED chips 2 may also adopt a staggered distribution on the substrate 1, or be referred to as a "delta" shaped distribution, that is, one light-emitting unit of the LED chip 2 is disposed at a position corresponding to the middle of two light-emitting units of the LED chips 2 in the adjacent row.

[0025] In this embodiment, the LED chip 2 adopts a blue LED, and a reflective cover 3 is disposed around the light-emitting unit of the LED chip 2, which can be used to reflect the light emitted from the LED chip 2 to the surroundings, so as to enhance the light intensity of the light-emitting surface. In specific implementation, the reflective cover 3 may also be disposed between the adjacent light-emitting units of the LED chips 2.

[0026] In this embodiment, the LED chips 2 adopt Mini LED chips. Each group of Mini LED chips usually contains one Mini LED, and in specific implementation, it may also contain a plurality of Mini LEDs. The portion within the center position of each group of Mini LED chips together with the surrounding reflective cover 3 is defined as one Pitch. The electroluminescent QD film adopts a micro-zone design, and the length of each zone is the same as the pitch value of the Mini LED chips, that is, it is preferable that each micro-zone of the electroluminescent QD film is disposed corresponding to one group of Mini LED chips.

[0027] In this embodiment, two layers of electroluminescent QD films are provided, which are defined as a first electroluminescent QD film 4 and a second electroluminescent QD film 5 respectively. The first electroluminescent QD film 4 adopts a red electroluminescent QD film, and the second electroluminescent QD film 5 adopts 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 specific implementation, the first electroluminescent QD film 4 may adopt a green electroluminescent QD film, and the second electroluminescent QD film 5 may adopt a red electroluminescent QD film. In specific implementation, only one layer of electroluminescent QD film may be provided, the one layer of electroluminescent QD film adopts a red electroluminescent QD film or a green electroluminescent QD film, and the other color is realized by the LED chip.

[0028] In this embodiment, the structure of the second electroluminescent QD film 5 is described by taking the second electroluminescent QD film 5 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, the bottom electrode 16, the hole injection layer 15, the hole transport layer 14, the quantum dot light-emitting layer 13, the electron transport layer 12 and the top electrode 11 are sequentially stacked from bottom to top. The QD film substrate 17 is the supporting structure of the second electroluminescent QD film 5, which is made of Al (aluminum foil) or Glass (glass, in this embodiment, glass material is preferably used). The bottom electrode 16 adopts ITO / MoO3 / NiO xThe materials used are as follows: the hole injection layer 15 is made of PEFOT:PSS, which has high conductivity, good hole transport capability, transparency and solution processability. In this embodiment, it is used as the hole injection layer (HIL). The 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. In this embodiment, it is used as the hole transport layer (HTL). The quantum dot light-emitting layer 13 is made of CdSe. In this embodiment, the emission color of the quantum dots can be achieved by adjusting their size. By adjusting 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 phosphors (half-width > 50nm). The electron transport layer 12 is made of ZnO, and the top electrode 11 is made of ITO.

[0029] 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: Bottom electrode 16 (e.g., ITO / MoO3 / NiO) x Holes are injected into the hole injection layer 15 and the hole transport layer 14 (PEDOT: PSS, PVK) and migrate to the quantum dot emission layer 13 (CdSe QD); electrons are injected into the top electrode 11 (ITO) and migrate to the quantum dot emission layer 13 (CdSe QD) via the electron transport layer 12 (ZnO).

[0030] (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).

[0031] (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).

[0032] 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).

[0033] 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.

[0034] This invention relates to a method for 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 from a backlight source. The basic working steps are as follows: First, only the blue LED is turned on, allowing its emitted blue light to illuminate the electroluminescent QD film in its unpowered 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 the 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.

[0035] 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.

[0036] The fabrication method of the RGB Mini LED backlight module based on dual electroluminescent QD film in this invention includes 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.

[0037] This invention employs a precise design with dual electroluminescent QD films layered together, 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.

[0038] 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 enables overall high color gamut, wide temperature range stability, and independent precise color control in RGB Mini LED backlighting. Color point correction through spectral synthesis at the backlight head allows for precise adjustment of the backlight head spectrum, fundamentally solving the brightness loss, low efficiency, and color consistency problems caused by panel calibration in traditional solutions.

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.

Images