TW202339243A - A μled display panel with a light blocking wall - Google Patents

Abstract

A micro-light-emitting diode display panel with a light blocking wall, comprising: a substrate; an electrode layer with a plurality of electrodes formed on the substrate to define a plurality of pixels; a plurality of micro-light-emitting diodes, individually adhered to the electrode; and a light blocking layer formed by black negative photoresist in the space between the micro light-emitting diodes, the light blocking wall constitutes a plurality of pixel regions to define the pixels; wherein, the light blocking wall is fabricated with a physical virtual mask by using laser direct writing exposure technology, and parts of the pixel regions are in a skewed state corresponding to the adhering state of the micro-LEDs.

Description

Micro-emitting diode display panel with light blocking layer

The present invention relates to a micro-light emitting diode technology, and in particular to a micro-light emitting diode display panel with a light blocking layer.

Micro Light Emitting Diode Display (μLED) is a new generation display that uses micro light emitting diodes as the light emitting elements of the display. This technology thins, miniaturizes, and arrays LEDs until the size of a single LED is only 1~10 μm. Then, the μLEDs are transferred to the circuit substrate in batches, and after surface adhesion, they are connected to the electrodes and transistors on the circuit substrate. , upper electrode, protective layer, etc. together constitute the μLED panel required for micro-light emitting diode displays.

μLED has many excellent characteristics such as self-illumination, low power consumption, fast response time, high brightness, ultra-high contrast, wide color gamut, wide viewing angle, ultra-thin and light, long service life and adaptability to various operating temperatures. Compared with LCD and OLED, The technical specifications of μLED have overwhelming advantages.

However, after μLED dies are transferred in large quantities and attached to the substrate 10 containing electrodes, there will be problems of lateral light mixing and substrate reflection during the emitting process of individual dies. Both of these conditions may cause pixels to fail. Problems such as clarity and reduced contrast. Therefore, the previous technology has adopted the production of black matrix to solve this technical problem.

However, in the actual mass production process, the process of mass transfer of die inevitably has problems of skew or uneven die arrangement, which results in the inability to improve the yield of the mass transfer process of die. Because if the black matrix is pre-made and then transferred in large quantities, if the die arrangement is skewed, the die must be recalibrated. In addition, in subsequent maintenance, it may also be difficult to replace the die due to the isolation of the black matrix.

In addition, the production of black matrix uses the exposure and development method, and the photomask must be prepared in advance. When the problem of grain skew occurs during the mass transfer process, the accuracy of the photomask will lead to further low mass production yields. problem.

Therefore, how to improve the mass production yield, solve possible skewed die placement, and then create a suitable black matrix structure has become an important research and development direction for the development of μLED technology.

In order to achieve the above object, the present invention provides a micro-light emitting diode display panel with a light blocking layer. Laser Direct Imaging (LDI) and development processes are used to produce the black matrix layer between the μLEDs, so as to accurately It can effectively produce a black matrix layer that can fill the gaps between μLEDs, thereby solving technical problems such as grain skew and low yield in the μLED manufacturing process, thereby achieving special technical effects such as high yield and reduced process costs.

The object of the present invention is to provide a micro-luminescent diode display panel with a light blocking layer, which includes: a substrate; an electrode layer with a plurality of electrodes formed on the substrate to define a plurality of pixels; a plurality of micro-luminescent diodes Polar bodies are individually adhered to the electrodes; and a light blocking layer is formed between the micro-light emitting diodes with black negative photoresist. The light blocking layer constitutes a plurality of pixel areas to define the pixels. ; Wherein, the light blocking layer is made with a physical virtual mask using laser direct writing exposure technology, and parts of the pixel areas are in a skewed state corresponding to the adhesion state of the micro-light emitting diodes.

The detailed features and advantages of the present invention are described in detail below in the implementation mode. The content is sufficient to enable anyone skilled in the relevant art to understand the technical content of the present invention and implement it according to the content disclosed in this specification, the patent scope and the drawings. , anyone familiar with the relevant art can easily understand the relevant objectives and advantages of the present invention.

According to an embodiment of the present invention, the present invention uses laser direct imaging and development processes to produce a black matrix layer between μLEDs, thereby accurately producing a black matrix layer that can fill the gaps between μLEDs. It then solves technical problems such as grain skew and low yield in the μLED manufacturing process, thereby achieving special technical effects such as high yield and reduced process costs.

Next, please refer to Figures 1 and 2A-2H for a flow chart of another embodiment of the manufacturing method of a micro-light emitting diode display panel with a light blocking layer of the present invention, as well as schematic cross-sectional views of each manufacturing stage and the finished product. view, wherein the manufacturing method of the micro-light emitting diode display panel with a light blocking layer of the present invention includes:

Step S111: Perform optical image scanning and calculation on the substrate on which a plurality of micro-light-emitting diodes are fabricated and generate a physical virtual mask. Through the execution of this step, the result of massive transfer of each micro-light-emitting diode in the already-produced micro-light-emitting diode substrate 10 can be understood. Among them, the distribution of micro-light emitting diodes is as shown in Figure 2F. The pixels are arranged in order as RGB pixels, namely pixel area 31-1-1, pixel area 31-1-2, and pixel area 31- in Figure 2F. 1-3, pixel area 31-1-4, pixel area 31-1-5, pixel area 31-1-6, Figure 2F is the configuration diagram of the physical virtual mask. Among them, the electrode layer 201-3-1 and the micro-light-emitting diode 301-3-1 formed on it that have been electrically connected are shown in Figure 2H (this figure is the final completed figure). . It can be found that Figure 2H is a schematic diagram showing that the micro-light emitting diodes in the pixel area 31-1-3 are skewed. When such a skew situation occurs, this step can use a physical virtual mask made from the actual photos taken. to correct the mask. In other words, each physical virtual mask is a customized product for each wafer, which can greatly improve the production yield of black matrix. Moreover, due to the use of physical virtual masks, the cost of physical masks can be reduced, thereby reducing production costs. Among them, the method of generating the physical virtual mask is optical image scanning and calculation, which can be carried out through a variety of methods, such as scanning through high-resolution optical cameras, lasers or infrared, and then each micro-luminescent diode is scanned. The position of the body is positioned, and finally, a positioning image information of the micro-luminescent diode (including its tilt angle and other information) is produced. Since the positioning image information represented by the physical virtual mask is to record the "actual position and tilt angle" of the micro-light-emitting diodes that have been transferred in large quantities, and then the black matrix produced through the subsequent laser cutting process can be It completely solves the skew problem that occurs during the mass transfer process, thereby greatly improving the process yield of micro-light-emitting diodes. In addition, the present invention can be manufactured individually for each micro-light-emitting diode substrate to individually solve the problem of skew of individual micro-light-emitting diodes of each substrate.

Step S112: Form a negative photoresist layer on the substrate that has been fabricated corresponding to the micro light-emitting diodes. The thickness of the negative photoresist layer is greater than the thickness of each micro light-emitting diode. As shown in FIG. 2B , the negative photoresist layer 30 can be formed by spin coating or spray coating. In addition, since the negative photoresist layer will be made into a black matrix structure, a negative photoresist material doped with black pigment can be used.

Step S113: Use the physical virtual mask to perform laser direct writing exposure on the negative photoresist layer, and remove the negative photoresist layer covering the micro-light emitting diodes. This step is generally called the laser direct writing exposure and development step. Since the photoresist material selected is a negative photoresist, the unexposed parts can be removed by the developer. As shown in Figure 2C, since the laser direct writing exposure head 50 can emit laser light 51, its exposure range can be directly controlled by computer software. In other words, since the physical virtual mask is an actual photo of each substrate 10 that has produced micro-light emitting diode pixel groups (as shown in Figure 2F), the laser direct writing exposure head 50 can emit The laser light 51 can directly adjust the skewed part without the need for a physical mask for exposure. The exposed negative photoresist layer 30 will remain to become the reserved black matrix structure of the present invention.

Step S114: Curing the negative photoresist layer that has not been removed to form a black matrix structure. For example, after exposure, a developer is used to remove the unexposed parts, and then the black matrix structure composed of the negative photoresist layer 30 is further cured into a permanent material layer through thermal curing or photo curing, as shown in 2E Figure 2F, Figure 2G, and Figure 2H.

Comparing Figure 2G and Figure 2H, it can be found that in Figure 2G, the micro-light emitting diode 301-1-1 in the local 2-pixel area 31-1-1 is produced normally, while in Figure 2H, the local 3-pixel area The micro-light emitting diode 301-1-3 in the area 31-1-3 is distorted due to the massive transfer. The present invention can adjust the physical virtual mask so that the window of pixel area 31-1-3 can be connected with other pixel areas 31-1-1, pixel area 31-2, pixel area 31-1-4, The pixel areas 31-1-5 and 31-1-6 are different; and by executing step S103, the window structures of different pixel areas 31-1-3 as shown in Figure 2H can be produced. In other words, part of the pixel area produced using the technology of the present invention will be in a skewed state corresponding to the adhesion state (skewed) of the micro-light emitting diodes. Among them, the distance between the micro-light emitting diode and one of the light blocking layers is less than 3 microns, or even worse, less than 1 micron, including those in which the pixel area is in a skewed state. Due to the technology used in the present invention, these skewed light blocking layers, as shown in Figure 2H, are a major technical feature of the present invention.

As for another embodiment of the present invention, the distance between the micro-light-emitting diodes and the black matrix layer can be widened, such as the average distance is 3 to 15 microns (um), so that the micro-light-emitting diodes can be tolerated to the greatest extent The skew, in this way, can standardize the structure of the pixel area without the need for fine-tuning. And when the micro-light-emitting diode is too skewed, the size and structure of the pixel area are adjusted.

In the embodiments of Figures 1 to 2H, each pixel occupies a pixel area, while in the embodiments of Figures 1 to 2G, every three pixels serve as a pixel area. However, the black matrix creation process is basically the same for both.

In the embodiments shown in Figures 1 to 2H, since each pixel occupies a separate pixel area, the present invention can further add steps S115 and S116 to fill each pixel area with a quantum dot layer. . The explanation is as follows:

Step S115: Form a quantum dot layer in the pixel area on the micro-light emitting diodes. As shown in Figure 2E, in each pixel area, depending on whether the micro-luminescent diode in each pixel area is red (R), green (G) or blue (B), the corresponding quantum dot (Quantum Dot, QD), can improve its luminous efficiency and color rendering, making the overall performance of micro-light-emitting diodes better. The quantum dot layer can be formed by coating, drip irrigation, inkjet, or glue dispensing.

Step S116: solidify the quantum dot layer. The solvent in the quantum dot layer 401-3-1 is removed by vacuum or heating, and finally it is cured with ultraviolet light or heat. This completes the solidification of the quantum dot layer in Figure 2E.

As for another embodiment of the present invention, the distance between the micro-light-emitting diodes and the black matrix layer can be widened, such as the average distance is 3 microns (um), which can tolerate the distortion of the micro-light-emitting diodes to a maximum extent. , in this way, the structure of the pixel area can be standardized without fine-tuning. And when the micro-light-emitting diode is too skewed, the size and structure of the pixel area are adjusted.

The photoresist in the present invention uses negative photoresist, but preferably, the photoresist layer of the present invention uses high-resolution negative photoresist. The material of the photoresist layer is mainly composed of polymer resin (Resin), photo initiator (Photo initiator), monomer (Monomer), solvent (Solvent), and additives (Additives).

Among the materials of the photoresist layer, the functions of polymer resin (Resin) are adhesion, developability, pigment dispersion, fluidity, heat resistance, chemical resistance, and analytical ability; the functions of photoinitiator (Photo initiator) The function lies in photosensitive properties and resolving power; the function of monomer lies in adhesion, development and resolving power; the function of solvent lies in viscosity and coating properties; the function of additives lies in coating property and leveling properties and foaming properties.

Polymer resin (Resin) can be a polymer or copolymer containing carboxylic acid group (COOH), such as acrylic resin, acrylic-epoxy (Epoxy) resin, acrylic Melamine (Melamine) , melamine) resin, acrylic-styrene (Styrene) resin, phenol-phenolic (PhenolicAldehyde) resin and other resins, or any mixture of the above resins, but is not limited to this. The weight percentage of resin in the photoresist can range from 3% to 30%.

Monomers can be divided into water-insoluble and water-soluble monomers. Among them, water-insoluble monomers can be pentoerythritol triacrylate, trimethyl ether propane triacrylate, and trimethyl ether propane. Trimethacrylate, tris,di-ethanol isocyanate triacrylate, di,trimethanol propane tetraacrylate, diisopentylerythritol pentaacrylate, pentaacrylate, isopenterythritol tetraacetate; dihexyltetraacetate hexaacetate alcohol, diisopentyltetraol hexaacetate, or multifunctional monomers, dendritic/polycluster acrylate oligomers, polyplex polyether acrylates, and ethyl urethane. The water-soluble monomer can be the monomer of Ethoxylated (polyoxyethylene) (referred to as EO) base and Propoxylated (polyoxypropylene) (referred to as PO); for example: di-(di- Oxyethylene (oxyethylene) vinyl acrylate unitary acid, 15 polyoxyethylene trimethanol propane triacrylate, 30 oxyethylene di, di-bis-p-phenolmethane diacrylate, 30 oxyethylene di-, di-bis-p- Phenolmethane dimethacrylate, eicosoxyethylene trimethanol propane triacrylate, pentadecyoxyethylene trimethanol propane triacrylate, methyloxyethylene monomethacrylate, dioxyethylene Ethylene diacrylate, ethylene glycol diacrylate, ethylene tetraethylene dimethacrylate, ethylene glycol diacrylate, polyoxyethylene dimethacrylate, polyoxypropylene monomethacrylate . Of course, two or more monomers can also be added to form a co-monomer. The weight percentage of the monomer or co-monomer in the photoresist can range from 0.1% to 99%.

The photo initiator can be selected from the group consisting of acetophenone, benzophenone or bis_imidazole, benzoin, and benzoin. Acyl compound (Benzil), α-amino ketone compound (α-amino ketone), acyl phosphine oxide compound (Acyl phosphine oxide) or benzoyl formate compound may be mixed with the above photoinitiator at will, but Not limited to this. The weight percentage of the photoinitiator in the photoresist may range from 0.1 to 10%.

The solvent (Solvent) can be ethylene glycol monopropylether, di-ethylene glycol dimethyl ether, tetrahydrofuran, ethylene glycol monomethyl ether, or ethylene glycol ether. (ethyleneglycol monoethyl ether), di-ethylene glycol mono-methylether, di-ethylene glycol mono-ethyl ether, di-ethylene glycol mono-butyl ether -butyl ether), propylene glycol mono-methyl ether acetate, propylene glycol mono-ethyl ether acetate, propylene glycol mono-propyl ether acetate, 3 -ethyl3_ethoxy propionate, etc., or any mixture of the above solvents, but is not limited thereto. The weight percentage of solvent in the photoresist can range from 0.1% to 99%.

The additive is generally a pigment dispersant, which is an ingredient that must be added to the photoresist containing pigments. It is generally a non-ionic surfactant, for example: Solsperse39000, Solsperse21000. The weight percentage range of this dispersant in the photoresist can be from to 0.1 to 5%.

When performing laser direct writing exposure and development in step S103 of the present invention, it further includes: (1) Substrate Clean; (2) Coating; (3) Pre-baking; 4) Exposure; (5) Developing and other processing steps.

The above two different embodiments are used to form the light blocking layer of the present invention in a post-processing manner. The specific thickness of the negative photoresist layer 30 can be 10 to 60 microns (um). The distance between the black matrix and the micro-light-emitting diodes can be set to less than 1 micron or 3 microns.

In addition, the RGB color definition mode in the embodiment is not intended to limit the present invention. As for micro-light emitting diode technology, the CIE color definition method or other color definition methods (for example, only using RG) can also be used. As far as the present invention is concerned, the technical focus is to use LDI technology to define each pixel space of the massively transferred micro-light emitting diodes through post-processing, and then use LDI technology to create a light blocking layer. If it is an embodiment of adding a quantum dot layer, only B, that is, a blue uLED, can be used, and the light emission relies on quantum dots.

As shown in the various embodiments mentioned above, the micro-light-emitting diode display panel with a light blocking layer of the present invention uses a physical virtual mask and laser direct writing exposure technology to solve the problem of large-scale micro-light-emitting diodes. The problem of grain distortion that occurs during the quantum transfer process is eliminated, thereby achieving special technical effects of high yield and lower cost. Furthermore, the special technical effects of blocking light and defining the pixel range of quantum dots can be further achieved.

Although the technical content of the present invention has been disclosed above in the form of preferred embodiments, it is not intended to limit the present invention. Any slight changes and modifications made by anyone skilled in the art without departing from the spirit of the present invention should be covered by the present invention. Within the scope of the present invention, the protection scope of the present invention shall be subject to the scope of the appended patent application.

2, 3: Partial 10:Substrate 30: Negative photoresist layer 31-1-1, 31-1-2, 31-1-3, 31-1-4, 31-1-5, 31-1-6: Pixel area 50: Laser direct writing exposure head 51:Laser light 201-3-1, 201-3-2, 201-3-3: Electrode layer 301-1-1, 301-1-2, 301-1-3: Micro-luminescent diodes 401-3-1: Quantum dot layer

Figure 1 is a flow chart of another embodiment of a method for manufacturing a micro-light emitting diode display panel with a light blocking layer of the present invention. Figures 2A-2H are schematic cross-sectional views of each production stage and a top view of the finished product in the process of another embodiment of the manufacturing method of a micro-light emitting diode display panel with a light blocking layer of the present invention.

without

3: Partial

31-1-3: Pixel area

301-1-3: Micro-luminescent diode

Claims (6)

A micro-light emitting diode display panel with a light blocking layer, including: a substrate; An electrode layer has a plurality of electrodes, is formed on the substrate, and defines a plurality of pixels; A plurality of micro-luminescent diodes are individually adhered to the electrode; and A light blocking layer is formed between the micro-luminescent diodes with black negative photoresist. The light blocking layer constitutes a plurality of pixel areas to define the pixels. Each of the pixel areas includes one of the micro-luminescent diodes. Diode; wherein, the light blocking layer is made with a physical virtual mask using laser direct writing exposure technology, and the parts in the pixel areas are skewed corresponding to the adhesion state of the micro-light-emitting diodes. condition. The micro-light-emitting diode display panel with a light-blocking layer as described in claim 1, wherein the thickness of the light-blocking layer is between 10 and 60 microns (um), which is thicker than the electrode layer and the micro-light-emitting diode. The combined thickness of body layers. The micro-light emitting diode display panel with a light blocking layer as claimed in claim 1, wherein a distance between the micro light emitting diodes and the light blocking layer is less than 1 micron. The micro-light emitting diode display panel with a light blocking layer as described in claim 2 further includes: A quantum dot layer is formed in the pixel area; the combined thickness of the quantum dot layer, the electrode layer and the micro-light emitting diode layer is less than the thickness of the light blocking layer. The micro-light emitting diode display panel with a light blocking layer as claimed in claim 4, wherein the quantum dot layer is formed by coating, drip irrigation, inkjet, or glue dispensing. The micro-light emitting diode display panel with a light blocking layer as claimed in claim 1, wherein a distance between the micro light emitting diodes and the light blocking layer is less than 3 microns.

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