Display device and method of manufacturing the same

Abstract

The application discloses a display device and a preparation method thereof, and belongs to the technical field of semiconductor devices. The preparation method of the display device provides wavelength conversion layers, the wavelength conversion layers include respectively provided first wavelength conversion layers and second wavelength conversion layers; the thickness of the second wavelength conversion layers is greater than the thickness of the first wavelength conversion layers; the first wavelength conversion layers are first transferred to pixel points through a substrate, and the second wavelength conversion layers are then transferred to other pixel points through the substrate; the preparation of the display device with sequentially transferred wavelength conversion layers is realized by respectively providing the wavelength conversion layers and sequentially transferring the wavelength conversion layers according to the thickness. The display device of the application includes at least two wavelength conversion layers with different thicknesses, so that there is no gap between the wavelength conversion layers and the pixel points, and the combination is more compact.

Description

Technical Field

[0001] This invention belongs to the field of semiconductor device technology, specifically relating to display devices and their fabrication methods. Background Technology

[0002] Micro-LEDs (micro-light-emitting diodes) are achieved through the miniaturization and matrixing of LEDs. Compared with traditional LED displays, Micro-LEDs differ in processes such as chip manufacturing, packaging, integration, backplane, and driving.

[0003] Micro-LED, also known as micro light-emitting diode, refers to a high-density integrated LED array. The distance between LED pixels in the array is on the order of 0.1-100 micrometers, and each LED pixel is self-emissive. Because a higher number of LEDs can be integrated on the same area of ​​chip, the integration density of Micro-LED micro-displays is greatly improved, thereby increasing display resolution while ensuring high brightness, enabling the design of low-power or high-brightness displays.

[0004] Full-color microdisplays have wide-ranging and significant application value, especially in near-eye displays, including AR and VR. However, there is still considerable room for improvement in the technology for achieving full-color microdisplays. The technology of integrating quantum dot color conversion layers onto a display substrate to achieve full color has recently received widespread attention and made considerable progress. This color conversion layer can be integrated into the display substrate through a transfer process. However, this involves transferring multiple color conversion layers, and traditional one-time overall transfer methods result in low yield rates. Furthermore, inconsistent thicknesses of different color conversion layers can lead to poor adhesion between certain color conversion layers and the display substrate, causing light leakage and reduced conversion efficiency, ultimately resulting in poor display quality. Summary of the Invention

[0005] Purpose of the invention: The purpose of this invention is to provide a method for transferring wavelength conversion layers, thereby changing the traditional method of transferring functional layers by transferring wavelength conversion layers sequentially; another purpose of this invention is to provide a display device.

[0006] Technical solution: To achieve the above-mentioned objective, the method for preparing the display device of the present invention includes:

[0007] A wavelength conversion layer is provided, the wavelength conversion layer comprising a first wavelength conversion layer and a second wavelength conversion layer respectively provided; the thickness of the second wavelength conversion layer is greater than the thickness of the first wavelength conversion layer.

[0008] The first wavelength conversion layer is first transferred to the pixel through the substrate, and the second wavelength conversion layer is then transferred to the other pixels through the substrate.

[0009] In some embodiments, the pixels are selected from any one of organic light-emitting diodes (OLEDs), liquid crystal displays (LCDs), and micro-light-emitting diodes, and the pixels are arranged in an array; the light emitted by the pixels is any one of red, green, blue, yellow, or ultraviolet light. The wavelengths of the first wavelength conversion layer, the second wavelength conversion layer, and the third wavelength conversion layer can be longer than the wavelength of the pixels.

[0010] In some embodiments, the first wavelength conversion layer is first transferred to the pixel via a substrate, and the second wavelength conversion layer is then transferred to other pixels via the substrate, including:

[0011] The first wavelength conversion layer is formed on the substrate; when transferring the first wavelength conversion layer, the first wavelength conversion layer is pressed onto the pixel; the substrate is then removed.

[0012] The second wavelength conversion layer is formed on the substrate; when transferring the second wavelength conversion layer, the second wavelength conversion layer is pressed onto the other pixels; the substrate is removed.

[0013] In some embodiments, forming the first wavelength conversion layer on the substrate includes: first forming a first filter layer on the substrate, and then forming the first wavelength conversion layer on the first filter layer; forming the second wavelength conversion layer on the substrate includes: first forming a second filter layer on the substrate, and then forming the second wavelength conversion layer on the second filter layer.

[0014] In some embodiments, after the substrate is removed, a first filter layer is covered on the first wavelength conversion layer, and a second filter layer is covered on the second wavelength conversion layer.

[0015] In some embodiments, the method for manufacturing the display device includes:

[0016] The wavelength conversion layer also includes a third wavelength conversion layer;

[0017] The thickness of the third wavelength conversion layer is greater than that of the second wavelength conversion layer. After the second wavelength conversion layer is transferred to other pixels, the third wavelength conversion layer is transferred to another pixel via the substrate, and then the substrate is removed. The wavelength conversion layers are transferred to their corresponding pixels in stages to ensure that neither the second nor the third wavelength conversion layer is affected by previously transferred layers during the transfer process. Through the staged transfer and the resulting height difference, the wavelength conversion layer directly contacts the corresponding pixel during each staged transfer, ensuring a tight fit.

[0018] In some embodiments, the third wavelength conversion layer is transferred across the substrate to another pixel, including:

[0019] The third wavelength conversion layer is formed on the substrate; when transferring the third wavelength conversion layer, the third wavelength conversion layer is pressed onto another pixel, and the substrate is removed; a height difference is formed between any two of the first wavelength conversion layer, the second wavelength conversion layer and the third wavelength conversion layer.

[0020] In some embodiments, the thickness of the wavelength conversion layer is between 500 nm and 100 micrometers.

[0021] In some embodiments, the thickness of the wavelength conversion layer is between 1 and 5 micrometers.

[0022] In some embodiments, the height difference is selected based on the thickness of the wavelength conversion layer. Further, the height difference is the difference in thickness between any two wavelength conversion layers (first, second, and third wavelength conversion layers).

[0023] In some embodiments, forming the third wavelength conversion layer on the substrate includes first forming a third filter layer on the substrate, and then forming the third wavelength conversion layer on the third filter layer.

[0024] In some embodiments, after the substrate is removed, the third filter layer is formed on the third wavelength conversion layer.

[0025] In some embodiments, the method further includes: providing a driving panel for driving the pixels disposed above the driving panel.

[0026] In some embodiments, an LED epitaxial layer is formed on the driving panel, and an array of micro-light-emitting diodes is formed on the LED epitaxial layer, with each pixel being one of the micro-light-emitting diodes.

[0027] In some embodiments, the LED epitaxial layer includes a first doped semiconductor layer, a second doped semiconductor layer, and an active layer located between the two; specifically including:

[0028] The first doped semiconductor layer is a continuous functional layer structure; the second doped semiconductor layer is etched to form a mesa structure, or the second doped semiconductor layer is ion implanted to form an array of micro light-emitting diodes;

[0029] Alternatively, the second doped semiconductor layer is a continuous functional layer structure; the first doped semiconductor layer is etched to form a mesa structure, or the second doped semiconductor layer is ion implanted to form an array of micro light-emitting diodes;

[0030] Alternatively, in each of the LED epitaxial layers, the first doped semiconductor layer, the second doped semiconductor layer, and the active layer are electrically isolated from each other.

[0031] In some embodiments, before transferring the wavelength conversion layer, a planarization process is performed on the pixel to form a planarization layer, wherein the planarization layer material includes any one of inorganic materials, metals, semiconductor oxides, black matrix colloids, color filter photoresists, and polyimide.

[0032] In some embodiments, the display device includes:

[0033] A driver panel for driving pixels positioned above the driver panel;

[0034] A wavelength conversion layer is applied to some or all of the pixels;

[0035] The wavelength conversion layer includes at least a first wavelength conversion layer and a second wavelength conversion layer, wherein the thickness of the second wavelength conversion layer is greater than the thickness of the first wavelength conversion layer.

[0036] In some embodiments, the pixel is a miniature light-emitting diode.

[0037] In some embodiments, the pixel emits a third color light, the pixel superimposed with the first wavelength conversion layer emits a first color light, and the pixel superimposed with the second wavelength conversion layer emits a second color light.

[0038] In some embodiments, the light emitted by the pixel is blue light, the first wavelength conversion layer is a red light wavelength conversion layer, and the second wavelength conversion layer is a green light wavelength conversion layer.

[0039] In some embodiments, a first filter layer is disposed on the first wavelength conversion layer, and a second filter layer is disposed on the second wavelength conversion layer.

[0040] In some embodiments, the wavelength conversion layer further includes a third wavelength conversion layer, the thickness of which is greater than the thickness of the second wavelength conversion layer.

[0041] In some embodiments, a third filter layer is disposed on the third wavelength conversion layer.

[0042] In some embodiments, the pixel emits a fourth color light, the pixel superimposed with the first wavelength conversion layer emits a first color light, the pixel superimposed with the second wavelength conversion layer emits a second color light, and the pixel superimposed with the third wavelength conversion layer emits a third color light.

[0043] In some embodiments, the light emitted by the pixel is ultraviolet light, the first wavelength conversion layer is a red wavelength conversion layer, the second wavelength conversion layer is a blue wavelength conversion layer, and the third wavelength conversion layer is a green wavelength conversion layer.

[0044] In some embodiments, a planarization layer is covered between the pixels, and the material of the planarization layer includes any one of black matrix colloid, color filter photoresist, and polyimide.

[0045] In some embodiments, the pixels superimposed with the first wavelength conversion layer emit a first wavelength of light; other pixels superimposed with the second wavelength conversion layer emit a second wavelength of light. The pixels superimposed with the third wavelength conversion layer emit a third wavelength of light.

[0046] In some embodiments, the pixels are miniature light-emitting diodes (LEDs) with a width of 100 nanometers to 100 micrometers; the pixels are arranged in an array, and the spacing between adjacent pixels is 1 to 10 micrometers. The spacing between adjacent pixels is the distance between the center points of two adjacent pixels.

[0047] In some embodiments, a height difference is formed between the first wavelength conversion layer and the second wavelength conversion layer.

[0048] In some embodiments, a first wavelength conversion layer or a second wavelength conversion layer is formed over the substrate, the formation being achieved by dry etching. The dry etching includes physical etching, chemical etching, or physicochemical etching.

[0049] In some embodiments, the first wavelength conversion layer and the second wavelength conversion layer are transferred in stages via a substrate, including:

[0050] First, a first wavelength conversion layer is formed on the substrate, and then the first wavelength conversion layer is transferred through the substrate; then, a second wavelength conversion layer is formed on the same substrate, and then the second wavelength conversion layer is transferred through the same substrate.

[0051] Alternatively, the first wavelength conversion layer or the second wavelength conversion layer may be formed on at least two of the substrates; the first wavelength conversion layer may be transferred first through the substrate on which the first wavelength conversion layer is formed, and then the second wavelength conversion layer may be transferred through the substrate on which the second wavelength conversion layer is formed.

[0052] In some embodiments, the pixels are located above the same drive panel.

[0053] In some embodiments, the driving panel is a silicon-based CMOS or a thin-film field-effect transistor.

[0054] In some embodiments, the formation of the LED epitaxial layer is achieved by transferring the LED substrate onto the driving panel via bonding.

[0055] In some embodiments, the sacrificial layer comprises photoresist, SU-8 (near-ultraviolet negative photoresist), polyimide (PI), SiO2, and SiN. x Any one of them.

[0056] In some embodiments, the flattening process includes:

[0057] Perform flattening processing to create flat surfaces between pixels;

[0058] A photoresist matrix is ​​formed by photoresist, and the light-emitting surface of the pixel is exposed by spin coating, drying, exposure, and development; for example, a photoresist material with a black matrix is ​​used.

[0059] Alternatively, use photoresist as a mask, then remove the mask to expose the light-emitting surface of the pixel;

[0060] Alternatively, a mesa structure can be formed by etching (dry etching or wet etching) to expose the light-emitting surface of the pixel.

[0061] In some embodiments, an adhesive layer is applied to the planarization layer. The adhesive layer is made of any one of SU-8 (near-ultraviolet negative photoresist), epoxy resin, or PR photoresist.

[0062] Beneficial Effects: Compared with the prior art, the fabrication method of the display device of the present invention provides a wavelength conversion layer, which includes a first wavelength conversion layer and a second wavelength conversion layer respectively provided; the thickness of the second wavelength conversion layer is greater than the thickness of the first wavelength conversion layer; the first wavelength conversion layer is first transferred to the pixel point through the substrate, and the second wavelength conversion layer is then transferred to other pixel points through the substrate; the present invention transfers the first wavelength conversion layer first, and then the second wavelength conversion layer, by transferring the thinner layer first and then the thicker layer, and by providing wavelength conversion layers separately and transferring the wavelength conversion layers in order of thickness, thereby achieving the fabrication of a display device with sequentially transferred wavelength conversion layers. The display device of the present invention includes at least two wavelength conversion layers of different thicknesses, so that there are no gaps between the wavelength conversion layers and the pixel points, resulting in a tighter bond. The present invention improves the efficiency of light source conversion by forming a height difference between different wavelength conversion layers, so that there are no gaps between the wavelength conversion layers and the bottom pixel points. In this invention, the pixels are selected from any one of organic light-emitting diodes (OLEDs), liquid crystal displays (LCDs), and micro light-emitting diodes, thereby realizing the fabrication of micro display devices and achieving full-color display of micro display chips while maintaining high light source conversion efficiency. Attached Figure Description

[0063] The technical solution and other beneficial effects of the present invention will become apparent from the following detailed description of specific embodiments of the invention, in conjunction with the accompanying drawings.

[0064] Figure 1 This is a schematic diagram of the first wavelength conversion layer on the substrate.

[0065] Figure 2 This is a schematic diagram of the transfer of the first wavelength conversion layer through a substrate;

[0066] Figure 3 A schematic diagram showing the removal of the substrate after the first wavelength conversion layer has been transferred;

[0067] Figure 4 This is a schematic diagram of the second wavelength conversion layer on the substrate;

[0068] Figure 5 This is a schematic diagram of transferring the second wavelength conversion layer through a substrate;

[0069] Figure 6 This is a schematic diagram of the bonding process for the second wavelength conversion layer;

[0070] Figure 7 A schematic diagram showing the removal of the substrate after transferring the second wavelength conversion layer;

[0071] Figure 8 This is a schematic diagram of the third wavelength conversion layer on the substrate;

[0072] Figure 9 This is a schematic diagram of the pressing process for the third wavelength conversion layer;

[0073] Figure 10 A schematic diagram showing the removal of the substrate after transferring the third wavelength conversion layer;

[0074] Figure 11 This is a schematic diagram showing the deposited isolation layer after the transfer is complete.

[0075] Figure 12 This is a top view of the pixel array;

[0076] Figure 13 A schematic diagram of a Bayer array for pixels;

[0077] Figure 14 A schematic diagram of a bar array of pixels;

[0078] Reference numerals: 100-substrate, 101-sacrificial layer, 102-adhesive layer, 103-passivation layer, 104-pixel, 105-driving panel, 106-first doped semiconductor layer, 107-common electrode, 108-second doped semiconductor layer, 109-planarization layer, 110-first wavelength conversion layer, 111-first filter layer, 112-display unit, 113-second wavelength conversion layer, 114-second filter layer, 115-box portion, 116-height difference, 117-third wavelength conversion layer, 118-third filter layer, 119-isolation layer. Detailed Implementation

[0079] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0080] This invention discloses many different embodiments or examples for implementing different structures of the invention. To simplify the disclosure, specific examples of components and arrangements are described herein. These are merely examples and are not intended to limit the invention. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, examples of various specific processes and materials are provided in this invention, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0081] Generally, terms can be understood at least in part according to the usage of the present invention. For example, the term "one or more" as used herein, at least in part according to the present invention, can be used to describe any component, structure, or feature in the singular, or in the plural, to describe a combination of components, structures, or features. Similarly, terms such as "a," "an," or "the" can also be understood, at least in part according to the present invention, to convey either a singular or a plural usage. Furthermore, the term "based on..." can be understood not necessarily to convey an exclusive set of factors, but rather, at least in part according to the present invention, can alternatively allow for the presence of additional factors that do not necessarily have to be explicitly described.

[0082] It should be readily understood that the meanings of “on,” “above,” and “on top of” in this invention should be interpreted in the broadest sense, such that “on” means not only “directly on something,” but also “on something” including the presence of an intermediate component or layer between the two, and “on something” or “above something” means not only “on something” or “above something,” but also “on something” or “above something” where no intermediate component or layer between the two exists.

[0083] Furthermore, for ease of description, spatial relative terms such as "below," "under," "lower," "above," and "upper" may be used in this invention to describe the relationship of one element or component to another element or component shown in the accompanying drawings. In addition to the orientations described in the figures, the spatial relative terms are also intended to cover different orientations of the device during use or operation. The device may be oriented in other ways (rotated 90 degrees or otherwise), and the spatial relative descriptive terms used in this invention can be interpreted accordingly.

[0084] As used in this invention, the term "layer" refers to a portion of material comprising a region of a certain thickness. A layer may extend over the entire lower or upper layer structure, or may have a extent smaller than that of the lower or upper layer structure. Furthermore, a layer may be a region of a homogeneous or heterogeneous continuous structure with a thickness less than the thickness of the continuous structure. For example, a layer may be located between the top and bottom surfaces of a continuous structure, or between any pair of horizontal planes therebetween. A layer may extend horizontally, vertically, and / or along a tapered surface. A substrate may be a single layer, which may include one or more layers, and / or may have one or more layers on, above, and / or below it. A single layer may include multiple layers. For example, a semiconductor layer may include one or more doped or undoped semiconductor layers, and may have the same or different materials.

[0085] As used in this invention, the term substrate 100 refers to the material on which subsequent material layers are added. The substrate 100 itself may be patterned. The material added on top of the substrate 100 may be patterned or may remain unpatterned. Furthermore, the substrate 100 may comprise a wide variety of semiconductor materials, such as silicon, silicon carbide, gallium nitride, germanium, gallium arsenide, indium phosphide, etc. Alternatively, the substrate 100 may be made of a non-conductive material, such as glass, plastic, or sapphire wafer.

[0086] In some embodiments, the pixel 104 is selected from any one of organic light-emitting diodes, LCDs, and micro light-emitting diodes, and the pixel 104 is arranged in an array.

[0087] In some embodiments, the present invention describes a display device and its fabrication method. The display device of the present invention uses a Micro-LED (Micro light-emitting diode) structure, where the size of the micro-LED is reduced to 100 nanometers to 100 micrometers. In Micro-LEDs, the Micro-LED array is highly integrated, and the distance between the pixels of the Micro-LEDs in the array is further reduced to the order of 10 micrometers. The Micro-LED display method involves connecting Micro-LED chips of 10 micrometer size or even smaller to a driving panel 105, achieving precise control over the light emission brightness of each Micro-LED chip. The fabrication method of the display device of the present invention is applicable to Micro-LED structures, enabling the fabrication of display devices with extremely small dimensions. In some embodiments, in the Micro-LED structure, the distance between the pixels of the Micro-LEDs in the array is less than 5 micrometers.

[0088] In some embodiments, for fabricating a Micro-LED display device, an epitaxial layer is bonded to a driving panel 105. The driving panel 105 includes a display substrate with a CMOS backplane or a TFT glass substrate. Then, an array of pixels 104 is formed on the epitaxial layer.

[0089] In some embodiments, the pixel array 104 is a Micro-LED array. The Micro-LEDs in this invention can be of common cathode, common anode, or be independent of each other.

[0090] In some embodiments, the common cathode structure is achieved by connecting a series of cathode electrodes. In some embodiments, a common anode structure or independent structures can also be used, as long as the pixel 104 can emit light normally.

[0091] In some embodiments, a wavelength conversion layer is provided, comprising a first wavelength conversion layer 110 and a second wavelength conversion layer 113, wherein the thickness of the second wavelength conversion layer 113 is greater than the thickness of the first wavelength conversion layer 110; the first wavelength conversion layer 110 is transferred first, followed by the second wavelength conversion layer 113. The wavelength conversion layer is transferred through a substrate 100, and is located on the substrate 100, with the wavelength conversion layer transferred above the pixel 104 via the substrate 100.

[0092] In some embodiments, the thickness of the wavelength conversion layer is between 500 nm and 100 micrometers.

[0093] In some embodiments, the thickness of the wavelength conversion layer is between 1 and 5 micrometers.

[0094] In some embodiments, the height difference 116 is selected based on the thickness of the wavelength conversion layer. Further, the height difference 116 is the difference in thickness between any two wavelength conversion layers formed between the first wavelength conversion layer 110, the second wavelength conversion layer 113, and the third wavelength conversion layer 117.

[0095] In some embodiments, the driving panel 105 is a silicon-based CMOS (Complementary Metal Oxide Semiconductor) or a thin-film field-effect transistor. A silicon-based CMOS is a chip with silicon as its substrate.

[0096] In some embodiments, the patterning scheme of the wavelength conversion layer on the substrate 100 can be arbitrarily selected.

[0097] In some embodiments, the material of the wavelength conversion layer includes, but is not limited to, quantum dots, phosphors, etc. The quantum dots may be colloidal quantum dots.

[0098] In some embodiments, the wavelength conversion layer transfer method involves first transferring the first wavelength conversion layer 110, then transferring the second wavelength conversion layer 113, and then transferring the third wavelength conversion layer 117.

[0099] In some embodiments, the wavelength conversion layer transfer method involves transferring the wavelength conversion layer to the driving panel 105 via the substrate 100 after the wavelength conversion layer is transferred, and then applying pressure to the wavelength conversion layer to firmly fix the wavelength conversion layer onto the driving panel 105, so that there is no gap between the wavelength conversion layer and the pixel 104.

[0100] In some embodiments, the material of the first wavelength conversion layer 110 includes quantum dots or phosphors; the material of the second wavelength conversion layer 113 includes quantum dots or phosphors; and the material of the third wavelength conversion layer 117 includes quantum dots or phosphors.

[0101] Methods for fabricating display devices include:

[0102] A wavelength conversion layer is provided, which includes a first wavelength conversion layer 110 and a second wavelength conversion layer 113, wherein the thickness of the second wavelength conversion layer 113 is greater than the thickness of the first wavelength conversion layer 110.

[0103] First, the first wavelength conversion layer 110 is transferred to the pixel 104 of the driving panel 105, and then the second wavelength conversion layer 113 is transferred to the pixel 104 of the driving panel 105.

[0104] In some embodiments, pressure is applied to the wavelength conversion layer by the substrate 100 to fix the wavelength conversion layer onto the drive panel 105.

[0105] In some embodiments, a sacrificial layer 101 is deposited on the substrate 100. The sacrificial layer 101 includes photoresist, SU-8 (near-ultraviolet negative photoresist), polyimide (PI), SiO2, and SiN. x .

[0106] In some embodiments, after the wavelength conversion layer is formed, in addition to removing excess wavelength conversion material, the sacrificial layer 101 also needs to be removed. Methods for removing the sacrificial layer 101 include, but are not limited to, stripping, wet etching, and mechanical polishing.

[0107] In some embodiments, when the sacrificial layer 101 is a positive photoresist, the positive photoresist is easily removed by organic solvents. When the sacrificial layer 101 is an inorganic material, such as silicon dioxide, aluminum oxide, or SiN... x Inorganic substances are easily and quickly removed by corrosive solutions such as HF.

[0108] In some embodiments, the display device includes a driving panel 105, an epitaxial layer, and pixels 104. An LED epitaxial layer is transferred onto the driving panel 105, and an array of pixels 104 is formed on the LED epitaxial layer. At least two wavelength conversion layers with different thicknesses are disposed on the pixels 104.

[0109] In some embodiments, the wavelength conversion layer includes at least two wavelength conversion layers, including a first wavelength conversion layer 110 and a second wavelength conversion layer 113, wherein the thickness of the second wavelength conversion layer 113 is greater than the thickness of the first wavelength conversion layer 110.

[0110] In some embodiments, the wavelength conversion layer further includes a third wavelength conversion layer 117, wherein the thickness of the third wavelength conversion layer 117 is greater than that of the second wavelength conversion layer 113, and the thickness of the second wavelength conversion layer 113 is greater than that of the first wavelength conversion layer 110.

[0111] In some embodiments, the pixel array 104 is planarized to form a planarization layer 109. The planarization process includes:

[0112] A flattening process is performed to create a flat surface between the 104 pixels;

[0113] A photoresist matrix is ​​formed by photoresist, and the light-emitting surface of pixel 104 is exposed by spin coating, drying, exposure and development; for example, a photoresist of black matrix material is used.

[0114] Alternatively, use photoresist as a mask, then remove the mask to expose the light-emitting surface of pixel 104;

[0115] Alternatively, a mesa structure can be formed by etching (dry etching or wet etching) to expose the light-emitting surface of pixel 104.

[0116] In some embodiments, an adhesive layer 102 is covered over the planarization layer 109. The adhesive layer 102 includes any one of SU-8 (near-ultraviolet negative photoresist), epoxy resin, and PR photoresist.

[0117] Photoresist (PR) is a photosensitive liquid mixture composed of three main components: photosensitive resin, photosensitive agent, and solvent. PR photoresist is divided into two types: positive PR and negative PR. In positive PR, the unexposed areas are retained after development, while in negative PR, the exposed areas are retained after development.

[0118] In some embodiments, the light emitted by pixel 104 is any one of red, green, blue, yellow, or ultraviolet light. The wavelengths of the first wavelength conversion layer 110, the second wavelength conversion layer 113, and the third wavelength conversion layer 117 can be longer than the wavelength of pixel 104.

[0119] In some embodiments, pixel 104 emits a third color light, pixel 104 superimposed with a first wavelength conversion layer 110 emits a first color light, and pixel 104 superimposed with a second wavelength conversion layer 113 emits a second color light.

[0120] In some embodiments, pixel 104 emits a fourth color light, pixel 104 superimposed with a first wavelength conversion layer 110 emits a first color light, pixel 104 superimposed with a second wavelength conversion layer 113 emits a second color light, and pixel 104 superimposed with a third wavelength conversion layer 117 emits a third color light.

[0121] In some embodiments, the light emitted by pixel 104 is red light. In some embodiments, the light emitted by pixel 104 is green light. In some embodiments, the light emitted by pixel 104 is blue light. In some embodiments, the light emitted by pixel 104 is ultraviolet light.

[0122] In some embodiments, the light emitted by pixel 104 is blue light, the first wavelength conversion layer 110 is a red light wavelength conversion layer, and the second wavelength conversion layer 113 is a green light wavelength conversion layer.

[0123] In some embodiments, the light emitted by pixel 104 is ultraviolet light, the first wavelength conversion layer 110 is a red light wavelength conversion layer, the second wavelength conversion layer 113 is a blue light wavelength conversion layer, and the third wavelength conversion layer 117 is a green light wavelength conversion layer.

[0124] In some embodiments, a passivation layer 103 is deposited on the second doped semiconductor layer 108. The material of the passivation layer 103 and the planarization layer 109 may be the same or different.

[0125] In some embodiments, the planarization layer 109 is made of any one of inorganic materials, metals, semiconductor oxides, black matrix colloids, color filter photoresists, and polyimide.

[0126] In some embodiments, the black matrix colloid is an organic black matrix photoresist.

[0127] In some embodiments, the passivation layer 103 includes a black matrix colloid, a color filter photoresist, and polyimide.

[0128] In some embodiments, an LED epitaxial layer is formed on the driving panel 105, and an array of micro light-emitting diodes is formed on the LED epitaxial layer, with each pixel 104 being a micro light-emitting diode.

[0129] In some embodiments, the LED epitaxial layer includes a first doped semiconductor layer 106, a second doped semiconductor layer 108, and an active layer located between the two; specifically including:

[0130] The first doped semiconductor layer 106 is a continuous functional layer structure; the second doped semiconductor layer 108 is etched to form a mesa structure, or the second doped semiconductor layer 108 is ion implanted to form an array of micro light-emitting diodes.

[0131] Alternatively, the second doped semiconductor layer 108 may be a continuous functional layer structure; the first doped semiconductor layer 106 may be etched to form a mesa structure, or the second doped semiconductor layer 108 may be ion implanted to form an array of micro light-emitting diodes.

[0132] Alternatively, in each LED epitaxial layer, the first doped semiconductor layer 106, the second doped semiconductor layer 108, and the active layer are electrically isolated from each other.

[0133] like Figure 1 As shown, the first wavelength conversion layer 110 is located on the substrate 100.

[0134] In some embodiments, a sacrificial layer 101 is first deposited on a substrate 100, and then a first wavelength conversion layer 110 is formed on the sacrificial layer 101.

[0135] In some embodiments, a first filter layer 111 is first formed on the sacrificial layer 101, and then a first wavelength conversion layer 110 is covered on the first filter layer 111. Alternatively, in some embodiments, after the first wavelength conversion layer 110 is transferred, the first filter layer 111 is covered on the first wavelength conversion layer 110.

[0136] like Figure 2 As shown, after the first wavelength conversion layer 110 is transferred to the corresponding pixel 104 through the substrate 100, pressure is applied to the substrate 100 to make the first wavelength conversion layer 110 cover the pixel 104, so that the first wavelength conversion layer 110 and the pixel 104 are more tightly bonded.

[0137] like Figure 3 As shown, after the first wavelength conversion layer 110 is transferred and pressed, the substrate 100 is removed.

[0138] like Figure 4 As shown, the second wavelength conversion layer 113 is located on the substrate 100. In some embodiments, a second filter layer 114 is first formed on the sacrificial layer 101, and then the second wavelength conversion layer 113 is covered on the second filter layer 114. Alternatively, in some embodiments, after the second wavelength conversion layer 113 is transferred, the second filter layer 114 is covered on the second wavelength conversion layer 113.

[0139] like Figure 5 and Figure 6 As shown, Figure 6 This is an enlarged view of the boxed portion 115. After the second wavelength conversion layer 113 is transferred from the substrate 100 to the other pixels 104, pressure is applied to the substrate 100 to make the second wavelength conversion layer 113 cover the other pixels 104, so that the second wavelength conversion layer 113 and the other corresponding pixels 104 are more tightly bonded.

[0140] The thickness of the second wavelength conversion layer 113 is greater than that of the first wavelength conversion layer 110. After the second wavelength conversion layer 113 is transferred, pressure is applied to the substrate 100 to press it together. At this time, there is a height difference 116 between the first wavelength conversion layer 110 and the second wavelength conversion layer 113 after the first transfer, so that there is a height difference 116 between the first wavelength conversion layer 110 and the substrate 100. During the process of the substrate 100 pressing the second wavelength conversion layer 113 together, the substrate 100 is also close to the first wavelength conversion layer 110 while pressing the second wavelength conversion layer 113 together. The height difference 116 serves as the space for the substrate 100 to press down.

[0141] The height difference 116 serves as the space for the substrate 100 to press down until the first wavelength conversion layer 110 and the substrate 100 gradually approach each other.

[0142] like Figure 7 As shown, after the second wavelength conversion layer 113 is transferred and pressed, the substrate 100 is removed.

[0143] In some embodiments, the wavelength conversion layer includes only a first wavelength conversion layer 110 and a second wavelength conversion layer 113, and the first wavelength conversion layer 110 and the second wavelength conversion layer 113 have different thicknesses. During the transfer process, the first wavelength conversion layer 110 is transferred first, and then the second wavelength conversion layer 113 is transferred. The wavelength conversion layer transfer is then complete.

[0144] In some embodiments, the wavelength conversion layer includes a first wavelength conversion layer 110 and a second wavelength conversion layer 113. The first wavelength conversion layer 110 and the second wavelength conversion layer 113 have different thicknesses. During the transfer process, the first wavelength conversion layer 110 is transferred first, then the second wavelength conversion layer 113 is transferred, and then the transparent area is transferred. The wavelength conversion layer transfer is then completed.

[0145] like Figure 8 As shown, the third wavelength conversion layer 117 is located on the substrate 100. In some embodiments, a third filter layer 118 is first formed on the sacrificial layer 101, and then the third wavelength conversion layer 117 is covered on the third filter layer 118. Alternatively, in some embodiments, after the second wavelength conversion layer 113 is transferred, the third filter layer 118 is covered on the third wavelength conversion layer 117.

[0146] like Figure 9 As shown, the thickness of the third wavelength conversion layer 117 is greater than the thickness of the second wavelength conversion layer 113.

[0147] In some embodiments, after the third wavelength conversion layer 117 is transferred, pressure is applied to the substrate 100, and there is a height difference 116 between the first wavelength conversion layer 110 and the substrate 100, and between the second wavelength conversion layer 113 and the substrate 100. During the process of pressing the third wavelength conversion layer 117 onto the substrate 100, the substrate 100 is also close to the first wavelength conversion layer 110 and the second wavelength conversion layer 113. The height difference 116 serves as the space for the substrate 100 to press down.

[0148] The height difference 116 serves as a space for the substrate 100 to press down, making the first wavelength conversion layer 110, the second wavelength conversion layer 113, and the pixel 104 more tightly bonded.

[0149] In some embodiments, after removing the substrate 100, a first filter layer 111, a second filter layer 114, and a third filter layer 118 are disposed on the first wavelength conversion layer 110, the second wavelength conversion layer 113, and the third wavelength conversion layer 117.

[0150] like Figure 11 As shown, an isolation layer 119 is provided on the flat layer 109.

[0151] In some embodiments, the first wavelength conversion layer 110, the second wavelength conversion layer 113, and the third wavelength conversion layer 117 correspond arbitrarily to RGB (red, green, blue).

[0152] In some embodiments, the first wavelength conversion layer 110 is red, the second wavelength conversion layer 113 is green, and the third wavelength conversion layer 117 is blue. In this case, the transfer is performed according to the thickness of the wavelength conversion layers, transferring the thinner ones first, and then the thicker ones.

[0153] In some embodiments, the first wavelength conversion layer 110 is red and has the thinnest thickness; the second wavelength conversion layer 113 is blue and has a medium thickness; and the third wavelength conversion layer 117 is green and has the thickest thickness. In this case, the transfer is performed according to the thickness of the wavelength conversion layers, transferring the thinner ones first, and then the thicker ones.

[0154] In some embodiments, the first wavelength conversion layer 110 is red and has the thinnest thickness; the second wavelength conversion layer 113 is green and has the thickest thickness.

[0155] like Figure 12 The image shown is a top view of a 104-pixel array. Figure 13 As shown, Figure 12 A schematic diagram of the Bayer pattern of the 104 pixels in the display unit 112; as shown. Figure 14 The diagram shown is a schematic of a stripe pattern of 104 pixels. In some embodiments, the first wavelength conversion layer 110 is red light, the second wavelength conversion layer 113 is green, and the third wavelength conversion layer 117 is blue. Figure 13 and Figure 14 All pixel arrangement methods can achieve single-chip full-color Micro-LED display.

[0156] In the above embodiments, the descriptions of each embodiment have different focuses. For parts not described in detail in a certain embodiment, please refer to the relevant descriptions in other embodiments.

[0157] The display device and its preparation method provided in the embodiments of the present invention have been described in detail above. Specific examples have been used in the present invention to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only for the purpose of helping to understand the technical solutions and core ideas of the present invention. Those skilled in the art should understand that they can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for fabricating a display device, characterized in that, include: A driving panel (105) is provided for driving pixels (104) disposed above the driving panel (105); A wavelength conversion layer is provided, the wavelength conversion layer comprising a first wavelength conversion layer (110) and a second wavelength conversion layer (113) respectively provided; the thickness of the second wavelength conversion layer (113) is greater than the thickness of the first wavelength conversion layer (110); The first wavelength conversion layer (110) is first transferred to a portion of the pixels (104) through the substrate (100). Pressure is applied to the substrate (100) to make the first wavelength conversion layer (110) cover the portion of the pixels (104). The second wavelength conversion layer (113) is then transferred to other pixels (104) through the substrate (100). Pressure is applied to the substrate (100) to make the second wavelength conversion layer (113) cover the other pixels (104), and there is a height difference (116) between the second wavelength conversion layer (113) and the first wavelength conversion layer (110).

2. The method for fabricating a display device according to claim 1, characterized in that, The pixels (104) are selected from any one of organic light-emitting diodes, LCDs, and micro light-emitting diodes; the pixels (104) are arranged in an array.

3. The method for fabricating a display device according to claim 1, characterized in that, The first wavelength conversion layer (110) is first transferred to a portion of the pixels (104) via the substrate (100), and the second wavelength conversion layer (113) is then transferred to the other pixels (104) via the substrate (100), including: The first wavelength conversion layer (110) is formed on the substrate (100); when transferring the first wavelength conversion layer (110), the first wavelength conversion layer (110) is pressed onto the pixel (104) of the portion; the substrate (100) is removed; The second wavelength conversion layer (113) is formed on the substrate (100); when transferring the second wavelength conversion layer (113), the second wavelength conversion layer (113) is pressed onto the other pixel (104); the substrate (100) is removed.

4. The method for fabricating a display device according to claim 3, characterized in that, Forming the first wavelength conversion layer (110) on the substrate (100) includes: first forming a first filter layer (111) on the substrate (100), and then forming the first wavelength conversion layer (110) on the first filter layer (111); Forming the second wavelength conversion layer (113) on the substrate (100) includes: first forming a second filter layer (114) on the substrate (100), and then forming the second wavelength conversion layer (113) on the second filter layer (114).

5. The method for fabricating a display device according to claim 3, characterized in that, After removing the substrate (100), a first filter layer (111) is covered on the first wavelength conversion layer (110), and a second filter layer (114) is covered on the second wavelength conversion layer (113).

6. The method for fabricating a display device according to claim 1, characterized in that, Also includes: The wavelength conversion layer also includes a third wavelength conversion layer (117); The thickness of the third wavelength conversion layer (117) is greater than the thickness of the second wavelength conversion layer (113); after the second wavelength conversion layer (113) is transferred to the other pixel (104), the third wavelength conversion layer (117) is transferred to another pixel (104) through the substrate (100), and then the substrate (100) is removed.

7. The method for fabricating a display device according to claim 6, characterized in that, The third wavelength conversion layer (117) is transferred to another pixel (104) via the substrate (100), including: The third wavelength conversion layer (117) is formed on the substrate (100); when transferring the third wavelength conversion layer (117), the third wavelength conversion layer (117) is pressed onto the other pixel (104), and the substrate (100) is removed; a height difference (116) is formed between any two of the first wavelength conversion layer (110), the second wavelength conversion layer (113) and the third wavelength conversion layer (117).

8. The method for fabricating a display device according to claim 7, characterized in that, The formation of the third wavelength conversion layer (117) on the substrate (100) includes first forming a third filter layer (118) on the substrate (100), and then forming the third wavelength conversion layer (117) on the third filter layer (118).

9. The method for fabricating a display device according to claim 8, characterized in that, After removing the substrate (100), the third filter layer (118) is formed on the third wavelength conversion layer (117).

10. The method for fabricating a display device according to claim 1, characterized in that, An LED epitaxial layer is formed on the driving panel (105), and an array of micro light-emitting diodes is formed on the LED epitaxial layer, with each pixel (104) being one of the micro light-emitting diodes.

11. The method for fabricating a display device according to claim 10, characterized in that, The LED epitaxial layer includes a first doped semiconductor layer (106), a second doped semiconductor layer (108), and an active layer located between the two; including: The first doped semiconductor layer (106) is a continuous functional layer structure; the second doped semiconductor layer (108) is etched to form a mesa structure, or the second doped semiconductor layer (108) is ion implanted to form an array of micro light-emitting diodes; Alternatively, the second doped semiconductor layer (108) is a continuous functional layer structure; the first doped semiconductor layer (106) is etched to form a mesa structure, or the second doped semiconductor layer (108) is ion implanted to form an array of micro light-emitting diodes; Alternatively, in each of the LED epitaxial layers, the first doped semiconductor layer (106), the second doped semiconductor layer (108), and the active layer are electrically isolated from each other.

12. The method for fabricating a display device according to claim 1, characterized in that, Before transferring the first wavelength conversion layer, a planarization process is performed on the pixel (104) to form a planarization layer (109), wherein the material of the planarization layer (109) includes any one of black matrix colloid, color filter photoresist, and polyimide.

13. A display device, characterized in that, include: A driving panel (105) is used to drive pixels (104) disposed above the driving panel (105); A wavelength conversion layer is applied to some or all of the pixels (104); The wavelength conversion layer includes at least a first wavelength conversion layer (110) and a second wavelength conversion layer (113). The thickness of the second wavelength conversion layer (113) is greater than the thickness of the first wavelength conversion layer (110). The first wavelength conversion layer (110) is tightly bonded to a portion of the pixels (104) by pressing. The second wavelength conversion layer (113) is tightly bonded to other pixels (104) by pressing. There is a height difference (116) between the second wavelength conversion layer (113) and the first wavelength conversion layer (110).

14. The display device according to claim 13, characterized in that, The pixels (104) are selected from any one of organic light-emitting diodes, LCDs, and micro light-emitting diodes; the pixels (104) are arranged in an array.

15. The display device according to claim 13, characterized in that, The pixel (104) emits a third color light, the pixel (104) is superimposed with the first wavelength conversion layer (110) to emit a first color light, and the pixel (104) is superimposed with the second wavelength conversion layer (113) to emit a second color light.

16. The display device according to claim 13, characterized in that, A first filter layer (111) is provided on the first wavelength conversion layer (110), and a second filter layer (114) is provided on the second wavelength conversion layer (113).

17. The display device according to claim 13, characterized in that, The wavelength conversion layer further includes a third wavelength conversion layer (117), the thickness of which is greater than the thickness of the second wavelength conversion layer (113).

18. The display device according to claim 17, characterized in that, A third filter layer (118) is provided on the third wavelength conversion layer (117).

19. The display device according to claim 17, characterized in that, The pixel (104) emits a fourth color light, the pixel (104) superimposed with the first wavelength conversion layer (110) emits a first color light, the pixel (104) superimposed with the second wavelength conversion layer (113) emits a second color light, and the pixel (104) superimposed with the third wavelength conversion layer (117) emits a third color light.

20. The display device according to claim 13, characterized in that, A planarization layer (109) is covered between the pixels (104); the material of the planarization layer (109) includes any one of inorganic materials, metals, semiconductor oxides, black matrix colloids, color filter photoresists, and polyimide.

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