Micro-LED full-color display module and preparation method

Abstract

The application discloses a Micro-LED full-color display module and a preparation method. A Micro-LED array capable of self-emitting white light is integrated on a driving substrate, and each pixel can independently control the self-emitting white light Micro-LED switch and brightness. The self-emitting white light Micro-LEDs are divided into three groups, wherein the surface of the self-emitting white light Micro-LEDs in the first group is provided with a red photonic crystal filter film, the surface of the self-emitting white light Micro-LEDs in the second group is provided with a green photonic crystal filter film, and the surface of the self-emitting white light Micro-LEDs in the third group is provided with a blue photonic crystal filter film. The light emitted by the self-emitting white light Micro-LEDs after passing through the filter film is red, green and blue, respectively, serving as a light-emitting pixel. The red, green and blue pixels are two-dimensionally and periodically arranged, so that at least one red, one green and one blue pixel are contained in each period, thereby forming a full-color pixel. The application can reduce the difficulty of Micro-LED full-color display pixel transfer, and improve the color purity and stability of the Micro-LED full-color display.

Description

Technical Field

[0001] This invention relates to the field of semiconductor light-emitting devices, and in particular to a Micro-LED full-color display module and its fabrication method. Background Technology

[0002] Micro-LED displays are an array display technology that shrinks the size of LEDs to tens or even a few micrometers, integrating pixels at a high density. Micro-LEDs offer advantages such as high brightness, wide color gamut, long lifespan, low energy consumption, and fast response time, making them a promising next-generation display technology with significant application potential in displays and visible light communication. Currently, there are several technical routes for Micro-LED full-color displays: A. Liquid Crystal Display (LCD) Full-Color Display Technology. LCD full-color displays achieve full-color display using a white backlight that emits white light, combined with color filters. LCDs are passive light-emitting displays; the white backlight is always on. The brightness and on / off state of the color pixels are controlled by the color filters and liquid crystals. Therefore, LCD full-color displays have low luminous efficacy and long response times. Furthermore, it is difficult to achieve pixel sizes at the Micro-LED level for LCD displays.

[0003] B. OLED Full-Color Display Technology. OLED full-color displays rely on organic light-emitting diodes (OLEDs) for light emission. Although this is an active light-emitting technology that can achieve high contrast, the organic materials in OLEDs are unstable, resulting in insufficient brightness.

[0004] C. Three-color integrated full-color display technology. Three-color integrated full-color display achieves full color by integrating blue, green, and red Micro-LEDs as the three RGB colors. This technology requires transferring the three colors of Micro-LEDs onto the same driving substrate. Due to the large number of Micro-LED display chips to be transferred—tens of thousands or even hundreds of thousands—a single transfer requires moving an enormous number of chips, demanding an extremely high transfer rate; this process is known as "mass transfer." Simultaneously, the pixel size of Micro-LED display chips is very small (<50μm), requiring high transfer precision and resulting in low yield. Therefore, the problems of mass transfer, low yield, high precision requirements, and slow transfer rate have hindered the commercialization of three-color integrated Micro-LED full-color displays.

[0005] D. Monolithic Integrated Full-Color Display Technology. There are two approaches to monolithic integrated full-color display. The first is monolithic integration technology combined with color conversion technology. A single ultraviolet / blue epitaxial wafer is fabricated into a monochromatic Micro-LED, and then red, green, and blue emitting media are layered on top of the Micro-LED to achieve full color. Common emitting media include phosphors and quantum dots, but phosphors and quantum dots not only have low color conversion rates but also poor luminous stability, making it difficult to achieve commercially viable Micro-LED full-color displays. The second approach is monolithic integrated vertically stacked full-color display technology, which vertically stacks the three colors of Micro-LEDs at a single pixel position. While this can improve pixel resolution, the fabrication of electrodes for different pixels and the protection between pixel layers are very difficult. Additionally, light emitted from the bottom pixel is blocked, resulting in low luminous efficiency. Summary of the Invention

[0006] The first objective of this invention is to provide a Micro-LED full-color display module.

[0007] The second objective of this invention is to provide a method for preparing a Micro-LED full-color display module, which can reduce the difficulty of pixel transfer in Micro-LED full-color displays and improve the color purity and stability of Micro-LED full-color displays.

[0008] The first objective of this invention is achieved as follows: A Micro-LED full-color display module includes a driving substrate capable of controlling the switching and brightness of each pixel, and a Micro-LED array capable of self-emitting white light integrated on the driving substrate. The module is characterized in that: these self-emitting white light Micro-LED arrays are divided into three groups, wherein: a red photonic crystal filter film is disposed on the surface of the first group of self-emitting white light Micro-LEDs, a green photonic crystal filter film is disposed on the surface of the second group of self-emitting white light Micro-LEDs, and a blue photonic crystal filter film is disposed on the surface of the third group of self-emitting white light Micro-LEDs; wherein: the light emitted by the self-emitting white light Micro-LEDs after passing through the red, green, and blue photonic crystal filter films is red, green, and blue, respectively, serving as light-emitting pixels; the red, green, and blue colors are arranged in a two-dimensional periodic pattern, such that each period contains at least one red, one green, and one blue color, thereby constituting a full-color pixel.

[0009] Furthermore, the self-emissive white light Micro-LED is made of GaN-based semiconductor material. The light-emitting layer of the self-emissive white light Micro-LED contains InGaN multiple quantum wells with various In components, which enables the self-emissive white light Micro-LED to emit white light containing blue, green and red spectral components when current is injected.

[0010] Furthermore, in InGaN multiple quantum wells with various In compositions, each quantum well is sandwiched between an n-type GaN layer and a p-type GaN layer, arranged in the following order: first n-type GaN layer, blue emitting quantum well layer, first p-type GaN layer, second n-type GaN layer, green emitting quantum well layer, second p-type GaN layer, third n-type GaN layer, red emitting quantum well layer, and third p-type GaN layer.

[0011] Furthermore, the red, green, and blue photonic crystal filter films are all composed of a sandwich-structured photonic crystal, with Bragg reflector (DBR) layers on the top and bottom, and a filter control layer in the middle. The filter films on different light-emitting pixels have the same structure for the top and bottom DBR layers, but the thickness of the middle filter control layer varies to obtain filter channels for different colors.

[0012] Furthermore, the structure of the lower DBR in the red, green, and blue photonic crystal filter films is (SiO2 / GaP). n The refractive index of the material in the middle filter control layer is between 1.4 and 2.2, and the material of the filter control layer is SiO2 or SiN. x The upper DBR structure is (GaP / SiO2). n n is the logarithm of DBR, 1≤n≤6.

[0013] The second objective of this invention is achieved as follows: A method for fabricating a Micro-LED full-color display module includes the following steps: (1) Fabricating a white-light-emitting GaN-based LED epitaxial wafer on a silicon substrate; (2) The white-emitting GaN-based LED epitaxial wafer was processed by photolithography and ICP etching to prepare a self-emitting white-emitting Micro-LED array. (3) Electrodes were fabricated on a self-emitting white light Micro-LED array using metal coating technology and stripping process; (4) The white-emitting Micro-LED pixel array with electrodes is connected to a pre-designed driving substrate through a metal bonding process and the silicon substrate is removed to obtain a self-emitting white-emitting Micro-LED display module. (5) A set of lower DBR and a filter control layer are deposited on the self-emitting white light Micro-LED display module obtained in step (4); the thickness of the filter control layer is just enough to ensure that the filter channel of the filter film formed with the upper DBR and the lower DBR is for red light to pass through, while other bands of visible light are reflected. (6) Etch the filter control layer at the selected green light pixel position so that the thickness of the etched filter control layer is just enough to allow green light to pass through the filter channel of the filter film formed with the upper DBR and the lower DBR, while other bands of visible light are reflected. (7) Etch the filter control layer again at the selected blue light pixel position so that the thickness of the etched filter control layer is just enough to allow blue light to pass through the filter channel of the filter film formed with the upper DBR and the lower DBR, while other bands of visible light are reflected. (8) Prepare the upper layer DBR.

[0014] Another typical method for manufacturing a Micro-LED full-color display module includes the following steps: (1) Fabricating a white-light-emitting GaN-based LED epitaxial wafer on a silicon substrate; (2) The white-emitting GaN-based LED epitaxial wafer was processed by photolithography and ICP etching to prepare a self-emitting white-emitting Micro-LED array. (3) Electrodes were fabricated on a self-emitting white light Micro-LED array using metal coating technology and stripping process; (4) The self-emitting white light Micro-LED array with electrodes is connected to a pre-designed driving substrate through a metal bonding process and the silicon substrate is removed to obtain a self-emitting white light Micro-LED display module. (5) A red photonic crystal filter film is prepared at the selected red pixel position on a visible light transparent substrate, a green photonic crystal filter film is prepared at the selected green pixel position, and a blue photonic crystal filter film is prepared at the selected blue pixel position to form a pixel filter film array. (6) Place the visible light transparent substrate with the prepared pixel filter film array on the self-emitting white light Micro-LED display module.

[0015] The beneficial effects of this invention are: 1. Self-emitting white light Micro-LED contains blue, green and red quantum wells. When powered on, it can simultaneously emit white light containing blue, green and red spectral components. By placing red, green and blue photonic crystal filter films on the self-emitting white light Micro-LED, light-emitting pixels that emit red, green and blue light can be obtained to achieve full-color display. 2. The blue, green, and red photonic crystal filter films are all (SiO2 / GaP). n SiO2(GaP / SiO2) n Or (SiO2 / GaP) n SiN x (GaP / SiO2)n The sandwich structure only requires changing the middle layer, either SiO2 or SiN. x With the thickness of [a certain thickness], a filter film corresponding to the wavelength of the light-emitting pixel can be obtained; 3. The full width at half maximum (FWHM) of the blue, green, and red photonic crystal filter films is less than 30 nm, which can obtain narrow emission peaks for blue, green, and red light, thereby improving the color purity and stability of Micro-LED full-color displays. 4. This invention can reduce the difficulty of pixel transfer in Micro-LED full-color displays and improve the color purity and stability of Micro-LED full-color displays. Attached Figure Description

[0016] Figure 1 The diagram shows the structure of the filter film in Embodiments 1, 2 and 3 of this invention and the corresponding reflection spectrum, where (a) is a blue photonic crystal filter film, (b) is a green photonic crystal filter film and (c) is a red photonic crystal filter film. Figure 2 A schematic diagram of the white light epitaxial wafer provided by the present invention; Figure 3 This is a schematic diagram corresponding to step (2) in Embodiment 1 provided by the present invention; Figure 4 This is a schematic diagram corresponding to step (3) in Embodiment 1 provided by the present invention; Figure 5 This is a schematic diagram corresponding to step (4) in Embodiment 1 provided by the present invention; Figure 6 This is a schematic diagram corresponding to step (5) in Embodiment 1 provided by the present invention; Figure 7 This is a schematic diagram corresponding to step (6) in Embodiment 1 provided by the present invention; Figure 8 This is a schematic diagram corresponding to step (7) in Embodiment 1 provided by the present invention; Figure 9 The schematic diagrams corresponding to step (2) in Embodiments 2 and 3 provided by the present invention; Figure 10 The schematic diagrams corresponding to step (3) in Embodiments 2 and 3 provided by the present invention; Figure 11 The schematic diagrams corresponding to step (4) in Embodiments 2 and 3 provided by the present invention; Figure 12 This is a schematic diagram corresponding to step (5) in Embodiment 2 provided by the present invention; Figure 13 This is a schematic diagram corresponding to step (6) in Embodiment 2 provided by the present invention; Figure 14 This is a schematic diagram corresponding to step (7) in Embodiment 2 provided by the present invention; Figure 15 This is a schematic diagram corresponding to step (5) in Embodiment 3 provided by the present invention; Figure 16 This is a schematic diagram corresponding to step (6) in Embodiment 3 provided by the present invention; Figure 17 The diagram shows the structure of the crystal filter film in Embodiment 4 of the present invention and the corresponding reflection spectrum, wherein (a) is a blue photonic crystal filter film, (b) is a green photonic crystal filter film, and (c) is a red photonic crystal filter film. Figure 18 This is a schematic diagram of the filter film in Embodiment 5 of the present invention, wherein (a) is a blue photonic crystal filter film, (b) is a green photonic crystal filter film, and (c) is a red photonic crystal filter film; Figure 19 The reflection spectrum of the filter film in Embodiment 5 of the present invention is shown, wherein (a) is a blue photonic crystal filter film, (b) is a green photonic crystal filter film, and (c) is a red photonic crystal filter film. Explanation of reference numerals in the attached figures: Substrate 100, First n-type GaN layer 201, Blue luminescent quantum well layer 301, First p-type GaN layer 401, Second n-type GaN layer 202, Green luminescent quantum well layer 302, Second p-type GaN layer 402, Third n-type GaN layer 203, Red luminescent quantum well layer 303, Third p-type GaN layer 403, P-electrode 500, N-electrode 600, Driving substrate 700, Lower DBR 801, Filter control layer 810 of red photonic crystal filter film, Filter control layer 811 of green photonic crystal filter film, Filter control layer 812 of blue photonic crystal filter film, Upper DBR 802, Visible light transparent substrate 900. Detailed Implementation

[0017] To make the technical problems, technical solutions and advantages of the present invention clearer, a detailed description will be given below in conjunction with specific embodiments. Example

[0018] Figure 1 The diagram shows the structure and corresponding reflection spectra of blue, green, and red photonic crystal filter films.

[0019] The structure and thickness of each layer of the blue photonic crystal filter film are as follows: Figure 1As shown in (a): SiO2 100nm / GaP 38nm / SiO2 100nm / GaP 38nm-SiO2 126nm-GaP 38nm / SiO2 100nm / GaP 38nm / SiO2 100nm. The channel wavelength of the blue photonic crystal filter film is 460nm, the transmittance is 98.5%, the full width at half maximum (FWHM) of the channel of the blue photonic crystal filter film is 7nm, and the reflectance of the blue photonic crystal filter film is >90% in the wavelength range of 470nm to 780nm.

[0020] The structure of the green photonic crystal filter film includes the material and thickness of each layer, as shown in the example. Figure 1 (b) shows the following: SiO2 100nm / GaP 38nm / SiO2 100nm / GaP 38nm-SiO2 168nm-GaP 38nm / SiO2 100nm / GaP 38nm / SiO2 100nm. The channel wavelength of the green photonic crystal filter film is 519nm, the transmittance is 98.3%, the full width at half maximum (FWHM) of the channel is 9nm, and the reflectance of the green photonic crystal filter film is >90% in the wavelength ranges of 435nm–508nm and 530nm–780nm.

[0021] The structure and thickness of each layer of the red photonic crystal filter film are as follows: Figure 1 (c) shows: SiO2 100nm / GaP 38nm / SiO2 100nm / GaP 38nm-SiO2 232nm-GaP 38nm / SiO2 100nm / GaP 38nm / SiO2 100nm. The channel wavelength of the red photonic crystal filter film is 620nm, the transmittance is 99.5%, the full width at half maximum (FWHM) of the channel of the red photonic crystal filter film is 9nm, and the reflectivity of the red photonic crystal filter film is >90% in the wavelength ranges of 445nm~605nm and 639nm~780nm.

[0022] A method for fabricating a gallium nitride-based Micro-LED full-color display module specifically includes the following steps: (1) Using MOCVD technology, a first n-type GaN layer 201, a blue light-emitting quantum well layer 301, a first p-type GaN layer 401, a second n-type GaN layer 202, a green light-emitting quantum well layer 302, a second p-type GaN layer 402, a third n-type GaN layer 203, a red light-emitting quantum well layer 303, and a third p-type GaN layer 403 are sequentially grown on a silicon substrate 100, as shown in the structure. Figure 2 As shown; (2) The white light gallium nitride-based epitaxial wafer is processed using photolithography and ICP etching techniques to etch the white light gallium nitride-based epitaxial wafer through to the first n-type GaN layer 201, exposing the mesa of the first n-type GaN layer 201 to form a self-emitting white light Micro-LED array, the structure of which is as follows. Figure 3 As shown; (3) Using metal coating technology and a stripping process, an n-electrode 600 is fabricated on the first n-type GaN layer 201 of each self-emissive white light Micro-LED array, and a p-electrode 500 is fabricated on the third p-type GaN layer 403 of each self-emissive white light Micro-LED array, as shown in the figure. Figure 4 As shown; (4) The self-emissive white light Micro-LED array with electrodes is connected to a pre-designed driving substrate 700 via metal bonding, and the silicon substrate 100 is removed to obtain a self-emissive white light Micro-LED display module, the structure of which is as follows: Figure 5 As shown; (5) A filter control layer 810, consisting of a lower DBR 801 and a red photonic crystal filter film, is deposited on the self-emitting white light Micro-LED display module obtained in step (4). The lower DBR 801 has a structure of SiO2 / GaP / SiO2 / GaP, with a SiO2 thickness of 100nm and a GaP thickness of 38nm. The filter control layer 810 is made of SiO2 with a thickness of 232nm, which satisfies the requirement that the filter film formed with the upper DBR 802 and the lower DBR 801 allows 620nm red light to pass through, while other visible light bands are reflected. The structure is as follows: Figure 6 As shown; (6) At the selected green pixel position ②, the filter control layer is etched so that the thickness of the filter control layer 811 of the etched green photonic crystal filter film is 168nm, which satisfies the requirement that the filter channel of the filter film formed with the upper DBR 802 and the lower DBR 801 allows 520nm green light to pass through while other visible light bands are reflected; at the selected blue pixel position ①, the filter control layer is etched so that the thickness of the filter control layer 812 of the etched blue photonic crystal filter film is 116nm, which satisfies the requirement that the filter channel of the filter film formed with the upper DBR 802 and the lower DBR 801 allows 460nm blue light to pass through while other visible light bands are reflected, as shown in the structure. Figure 7 As shown; (7) Finally in Figure 7 On top of the existing structure, a higher layer of DBR 802 is grown. Its structure is SiO2 / GaP / SiO2 / GaP, with a SiO2 thickness of 100 nm and a GaP thickness of 38 nm. The structure is as follows: Figure 8 As shown.

[0023] The filter membrane structures and filtering effects obtained at positions ①, ②, and ③ after the above steps are shown in the figures. Figure 1 (a), Figure 1 (b) and Figure 1 (c) shows that the self-emitting white light Micro-LED at position ① emits blue light after passing through a blue photonic crystal filter film, the self-emitting white light Micro-LED at position ② emits green light after passing through a green photonic crystal filter film, and the self-emitting white light Micro-LED at position ③ emits red light after passing through a red photonic crystal filter film, thereby achieving full-color display. Example

[0024] A method for fabricating a gallium nitride-based Micro-LED full-color display module specifically includes the following steps: (1) Using MOCVD technology, a first n-type GaN layer 201, a blue light-emitting quantum well layer 301, a first p-type GaN layer 401, a second n-type GaN layer 202, a green light-emitting quantum well layer 302, a second p-type GaN layer 402, a third n-type GaN layer 203, a red light-emitting quantum well layer 303, and a third p-type GaN layer 403 are sequentially grown on a silicon substrate 100, as shown in the structure. Figure 2 As shown; (2) The white-light gallium nitride-based epitaxial wafer was processed using photolithography and ICP etching techniques. The white-light gallium nitride-based epitaxial wafer was etched onto the surface of the first n-type GaN layer 201 to fabricate a self-emitting white-light Micro-LED array, the structure of which is as follows. Figure 9 As shown; (3) Using metal coating technology and a stripping process, an n-electrode 600 is fabricated on the first n-type GaN layer 201 of the self-emitting white light Micro-LED array, and a p-electrode 500 is fabricated on the third p-type GaN layer 403 of the self-emitting white light Micro-LED array, as shown in the figure. Figure 10 As shown; (4) The self-emissive white-light Micro-LED array with electrodes is connected to a pre-designed driving substrate 700 via metal bonding, and the silicon substrate 100 is removed to obtain a self-emissive white-light Micro-LED display module, the structure of which is as follows: Figure 11 As shown; (5) A filter control layer 810, consisting of a lower DBR 801 and a red photonic crystal filter film, is deposited on the self-emitting white light Micro-LED display module obtained in step (4). The lower DBR 801 has a structure of SiO2 / GaP / SiO2 / GaP, with a SiO2 thickness of 100nm and a GaP thickness of 38nm. The filter control layer 810 is made of SiO2 with a thickness of 232nm, which satisfies the requirement that the filter film formed with the upper DBR 802 and the lower DBR 801 allows 620nm red light to pass through, while other visible light bands are reflected. The structure is as follows: Figure 12 As shown; (6) At the selected green pixel position ②, the filter control layer is etched so that the thickness of the filter control layer 811 of the etched green photonic crystal filter film is 168nm, which just satisfies the requirement that the filter channel of the filter film formed with the upper DBR 802 and the lower DBR 801 allows 520nm green light to pass through, while other visible light bands are reflected; at the selected blue pixel position ①, the filter control layer is etched so that the thickness of the filter control layer 812 of the etched blue photonic crystal filter film is 116nm, which just satisfies the requirement that the filter channel of the filter film formed with the upper DBR 802 and the lower DBR 801 allows 460nm blue light to pass through, while other visible light bands are reflected; the structure is as follows. Figure 13 As shown.

[0025] (7) Finally in Figure 7 On top of the existing structure, a higher layer of DBR 802 is grown. Its structure is SiO2 / GaP / SiO2 / GaP, with a SiO2 thickness of 100 nm and a GaP thickness of 38 nm. The structure is as follows: Figure 14 As shown.

[0026] The filter membrane structures and filtering effects obtained at positions ①, ②, and ③ after the above steps are shown in the figures. Figure 1 (a), Figure 1 (b) and Figure 1 (c) shows that the self-emitting white light Micro-LED at position ① emits blue light after passing through a blue photonic crystal filter film, the self-emitting white light Micro-LED at position ② emits green light after passing through a green photonic crystal filter film, and the self-emitting white light Micro-LED at position ③ emits red light after passing through a red photonic crystal filter film, thereby achieving full-color display. Example

[0027] A method for fabricating a gallium nitride-based Micro-LED full-color display module specifically includes the following steps: (1) Using MOCVD technology, a first n-type GaN layer 201, a blue light-emitting quantum well layer 301, a first p-type GaN layer 401, a second n-type GaN layer 202, a green light-emitting quantum well layer 302, a second p-type GaN layer 402, a third n-type GaN layer 203, a red light-emitting quantum well layer 303, and a third p-type GaN layer 403 are sequentially grown on a silicon substrate 100, as shown in the structure. Figure 2 As shown; (2) The white-light gallium nitride-based epitaxial wafer was processed using photolithography and ICP etching techniques. The white-light gallium nitride-based epitaxial wafer was etched onto the surface of the first n-type GaN layer 201 to fabricate a self-emitting white-light Micro-LED array, the structure of which is as follows. Figure 9 As shown; (3) Using metal coating technology and a stripping process, an n-electrode 600 is fabricated on the first n-type GaN layer 201 of the self-emitting white light Micro-LED array, and a p-electrode 500 is fabricated on the third p-type GaN layer 403 of the self-emitting white light Micro-LED array, as shown in the figure. Figure 10 As shown; (4) The self-emissive white-light Micro-LED array with electrodes is connected to a pre-designed driving substrate 700 via metal bonding, and the silicon substrate 100 is removed to obtain a self-emissive white-light Micro-LED display module, the structure of which is as follows: Figure 11 As shown; (5) A pixel filter film array, comprising a red photonic crystal filter film, a green photonic crystal filter film, and a blue photonic crystal filter film, is fabricated on a visible light transparent substrate. First, a lower DBR 801 and a red photonic crystal filter film filter control layer 810 are deposited on the visible light transparent substrate. The lower DBR 801 has a structure of SiO2 / GaP / SiO2 / GaP, with a SiO2 thickness of 100 nm and a GaP thickness of 38 nm. The filter control layer 810 of the red photonic crystal filter film has a thickness of 232 nm, which satisfies the requirement that the filter channel formed by the upper DBR 802 and the lower DBR 801 allows 620 nm red light to pass through while other visible light bands are reflected. At the selected green pixel position ②, the filter control layer is etched, making the thickness of the etched green photonic crystal filter film filter control layer 811 168 nm, which satisfies the requirement that the filter channel formed by the upper DBR 802 and the lower DBR 801 allows 620 nm red light to pass through while other visible light bands are reflected. The filter film formed by DBR 801 allows 520nm green light to pass through, while other visible light wavelengths are reflected. At the selected blue light pixel location ①, a filter control layer is etched, making the thickness of the etched blue photonic crystal filter film's filter control layer 812 116nm. This perfectly satisfies the requirement that the filter film formed by the upper DBR 802 and lower DBR 801 allows 460nm blue light to pass through, while other visible light wavelengths are reflected. Finally, DBR 802 is grown on top, with a structure of SiO2 / GaP / SiO2 / GaP, where the SiO2 thickness is 100nm and the GaP thickness is 38nm. Figure 15 As shown; (6) Place the prepared pixel filter film array on a visible light transparent substrate onto a white-light emitting Micro-LED display module, as shown in the structure. Figure 16 As shown.

[0028] The filter membrane structures and filtering effects obtained at positions ①, ②, and ③ after the above steps are shown in the figures. Figure 1 (a), Figure 1 (b) and Figure 1 As shown in (c), the Micro-LED that emits white light at position ① emits blue light after passing through a blue photonic crystal filter film, the Micro-LED that emits white light at position ② emits green light after passing through a green photonic crystal filter film, and the Micro-LED that emits white light at position ③ emits red light after passing through a red photonic crystal filter film, thereby achieving full-color display. Example

[0029] The fabrication method of the Micro-LED full-color display module in this embodiment is the same as that in Embodiments 1, 2 or 3, except that the materials of the filter control layers of the blue photonic crystal filter film, the green photonic crystal filter film and the red photonic crystal filter film are different.

[0030] like Figure 17 The diagram shows the structural schematics and corresponding reflection spectra of the blue, green, and red photonic crystal filter films in this embodiment 4.

[0031] The structure and thickness of each layer of the blue photonic crystal filter film are as follows: Figure 17 As shown in (a): SiO2 100nm / GaP38nm / SiO2 100nm / GaP 38nm-SiNx 88nm-GaP 38nm / SiO2 100nm / GaP38nm / SiO2 100nm; the channel wavelength of the blue photonic crystal filter film is 465nm, the transmittance is 98.2%, the full width at half maximum (FWHM) of the channel of the blue photonic crystal filter film is 10nm, and the reflectance of the blue photonic crystal filter film is >90% in the wavelength range of 478nm to 717nm.

[0032] The structure of the green photonic crystal filter film includes the material and thickness of each layer, as shown in the example. Figure 17 (b) shows: SiO2 100nm / GaP 38nm / SiO2 100nm / GaP 38nm-SiN x The green photonic crystal filter film has a channel wavelength of 532nm, a transmittance of 99.7%, a full width at half maximum (FWHM) of 8nm, and a reflectivity of >90% in the wavelength ranges of 433nm–519nm and 547nm–763nm. The filter film is composed of 127nm-GaP 38nm / SiO2 100nm / GaP 38nm / SiO2 100nm.

[0033] The structure and thickness of each layer of the red photonic crystal filter film are as follows: Figure 17 (c) shows: SiO2 100nm / GaP 38nm / SiO2 100nm / GaP 38nm-SiN x The red photonic crystal filter film has a channel wavelength of 623nm, a transmittance of 99.1%, a full width at half maximum (FWHM) of 12nm, and a reflectance of >90% in the wavelength ranges of 455nm–606nm and 652nm–800nm. The filter film is composed of 177nm-GaP 38nm / SiO2 100nm / GaP 38nm / SiO2 100nm. Example

[0034] The fabrication method of the Micro-LED full-color display module in this embodiment is the same as that in Embodiments 1, 2 or 3, except that the structures of the blue photonic crystal filter film, the green photonic crystal filter film and the red photonic crystal filter film are different.

[0035] Figure 18These are schematic diagrams of the blue, green, and red photonic crystal filter films in Example 5. Figure 19 The values ​​represent the reflection spectra of the corresponding blue, green, and red photonic crystal filter films.

[0036] The structure and thickness of each layer of the blue photonic crystal filter film are as follows: Figure 18 (a) shows: (SiO2 100nm / GaP 38nm) 4 SiO2 113nm(SiO2100nm / GaP 38nm) 4 The channel wavelength is 456nm, the transmittance is 98.7%, the full width at half maximum (FWHM) of the blue photonic crystal filter film is 2nm, and the reflectance of the blue photonic crystal filter film is >90% in the wavelength range of 459nm to 736nm.

[0037] The structure of the green photonic crystal filter film includes the material and thickness of each layer, as shown in the example. Figure 18 (b) shows: (SiO2 100nm / GaP 38nm) 4 SiO2 156nm (SiO2 100nm / GaP 38nm) 4 The green photonic crystal filter film has a channel wavelength of 504nm, a transmittance of 98.7%, a full width at half maximum (FWHM) of 0.4nm, and a reflectance of >90% in the wavelength ranges of 445nm–503nm and 504nm–751nm.

[0038] The structure and thickness of each layer of the red photonic crystal filter film are as follows: Figure 18 (c) shows: (SiO2 100nm / GaP 38nm) 4 SiO2 251nm(SiO2 100nm / GaP 38nm) 4 The red photonic crystal filter film has a channel wavelength of 643nm, a transmittance of 99.2%, a full width at half maximum (FWHM) of 1nm, and a reflectance of >90% in the wavelength ranges of 453nm–642nm and 645nm–765nm.

[0039] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A Micro-LED full-color display module, comprising a driving substrate capable of controlling the switching and brightness of each pixel, and a Micro-LED array integrated on the driving substrate capable of self-emitting white light, characterized in that: These self-emissive white-light Micro-LED arrays are divided into three groups: a red photonic crystal filter film is disposed on the surface of the first group of self-emissive white-light Micro-LEDs, a green photonic crystal filter film is disposed on the surface of the second group of self-emissive white-light Micro-LEDs, and a blue photonic crystal filter film is disposed on the surface of the third group of self-emissive white-light Micro-LEDs. The light emitted by the self-emissive white-light Micro-LEDs after passing through the red, green, and blue photonic crystal filter films is red, green, and blue, respectively, serving as light-emitting pixels. The red, green, and blue light are arranged in a two-dimensional periodic pattern, with each period containing at least one red, one green, and one blue light, thus forming a full-color pixel. The red, green, and blue photonic crystal filter films are composed of a sandwich-structured photonic crystal, with Bragg reflector (DBR) layers on the top and bottom, and a filter control layer in the middle. The filter films disposed on different light-emitting pixels have the same structure for the top and bottom DBR layers, but the thickness of the middle filter control layer is different to obtain filter channels for different colors.

2. The Micro-LED full-color display module according to claim 1, characterized in that: The self-emitting white light Micro-LED is made of GaN-based semiconductor material. The light-emitting layer of the self-emitting white light Micro-LED contains InGaN multiple quantum wells with various In components, which enables the self-emitting white light Micro-LED to emit white light containing blue, green and red spectral components when current is injected.

3. The Micro-LED full-color display module according to claim 2, characterized in that: In the InGaN multiple quantum wells with various In components, each component's quantum well is sandwiched between an n-type GaN layer and a p-type GaN layer, arranged in the following order: first n-type GaN layer, blue emitting quantum well layer, first p-type GaN layer, second n-type GaN layer, green emitting quantum well layer, second p-type GaN layer, third n-type GaN layer, red emitting quantum well layer, and third p-type GaN layer.

4. The Micro-LED full-color display module according to claim 1, characterized in that: The lower DBR structure in the red, green, and blue photonic crystal filter films is (SiO2 / GaP). n The refractive index of the material in the middle filter control layer is between 1.4 and 2.2, and the material of the filter control layer is SiO2 or SiN. x The upper DBR structure is (GaP / SiO2). n n is the logarithm of DBR, 1≤n≤6.

5. A method for manufacturing a Micro-LED full-color display module, characterized in that: Includes the following steps: (1) Fabricating a white-light-emitting GaN-based LED epitaxial wafer on a silicon substrate; (2) The white-emitting GaN-based LED epitaxial wafer was processed by photolithography and ICP etching to prepare a self-emitting white-emitting Micro-LED array. (3) Electrodes were fabricated on a self-emitting white light Micro-LED array using metal coating technology and stripping process; (4) The self-emitting white light Micro-LED array with electrodes is connected to a pre-designed driving substrate through a metal bonding process and the silicon substrate is removed to obtain a self-emitting white light Micro-LED display module. (5) A set of lower DBR and a filter control layer are deposited on the self-emitting white light Micro-LED display module obtained in step (4); the thickness of the filter control layer is just enough to ensure that the filter channel of the filter film formed with the upper DBR and the lower DBR is for red light to pass through, while other bands of visible light are reflected. (6) Etch the filter control layer at the selected green light pixel position so that the thickness of the etched filter control layer is just enough to allow green light to pass through the filter channel of the filter film formed with the upper DBR and the lower DBR, while other bands of visible light are reflected. (7) Etch the filter control layer again at the selected blue light pixel position so that the thickness of the etched filter control layer is just enough to allow blue light to pass through the filter channel of the filter film formed with the upper DBR and the lower DBR, while other bands of visible light are reflected. (8) Prepare the upper layer DBR.

6. A method for preparing a Micro-LED full-color display module as described in claim 1, characterized in that: Includes the following steps: (1) Fabricating a white-light-emitting GaN-based LED epitaxial wafer on a silicon substrate; (2) The white-emitting GaN-based LED epitaxial wafer was processed by photolithography and ICP etching to prepare a self-emitting white-emitting Micro-LED array. (3) Electrodes were fabricated on a self-emitting white light Micro-LED array using metal coating technology and stripping process; (4) The self-emitting white light Micro-LED array with electrodes is connected to a pre-designed driving substrate through a metal bonding process and the silicon substrate is removed to obtain a self-emitting white light Micro-LED display module. (5) A red photonic crystal filter film is prepared at the selected red pixel position on a visible light transparent substrate, a green photonic crystal filter film is prepared at the selected green pixel position, and a blue photonic crystal filter film is prepared at the selected blue pixel position to form a pixel filter film array. (6) Place the visible light transparent substrate with the prepared pixel filter film array on the self-emitting white light Micro-LED display module.

Images