Method for manufacturing display panel and display panel

Abstract

This application belongs to the field of display technology, specifically relating to a method for fabricating a display panel and the display panel itself. The fabrication method includes: providing a substrate on which multiple light-emitting device layers are disposed; sequentially forming a first inorganic encapsulation layer and an organic encapsulation layer; providing a transfer substrate having interconnected first protrusions and second protrusions of different heights; pressing the transfer substrate against the organic encapsulation layer to form a first recess and a second recess of different depths; removing the transfer substrate; sequentially forming a second inorganic encapsulation layer and a color filter layer, wherein the color filter layer fills the recessed patterns and has a flat surface; the first recess corresponds to the area between the light-emitting device layers and is filled with a stacked structure of at least two colors of color resist blocks, and the second recess corresponds to the light-emitting device layer and is filled with a single-color color resist block. This application pre-defines recessed patterns on the organic encapsulation layer that are complementary to the thickness distribution of the color filter layer, achieving self-planarization of the color filter layer, reducing panel thickness, improving bending performance and light extraction efficiency, and simplifying the manufacturing process.

Description

Technical Field

[0001] This application belongs to the field of display technology, specifically relating to a method for preparing a display panel and the display panel itself. Background Technology

[0002] Organic light-emitting diode (OLED) display panels are widely used in the display field due to their advantages such as self-illumination, high contrast, and wide viewing angle. To reduce power consumption and improve light extraction efficiency, related technologies often fabricate color filter layers on thin-film encapsulation (TFE) layers to replace polarizers, i.e., COE (Color Filter on Encapsulation) structures. To further simplify the manufacturing process and reduce costs, some COE structures use red, green, and blue color resist blocks stacked in the non-light-emitting area to replace the traditional black matrix (BM) to achieve a light-blocking effect.

[0003] However, in the structure where RGB color resist stacking replaces BM, the stacked thickness of the color resist in the non-light-emitting area is much greater than the thickness of a single layer of color resist in the light-emitting area, resulting in an uneven surface on the color filter layer. To meet the flatness requirements, an additional flattening layer needs to be applied, which not only increases the panel thickness and affects bending performance, but also reduces light extraction efficiency and increases process complexity. Summary of the Invention

[0004] The purpose of this application is to provide a method for manufacturing a display panel and a display panel that can achieve self-planarization of the color filter layer, reduce panel thickness, improve bending performance and light extraction efficiency, and simplify the manufacturing process.

[0005] This application provides a method for fabricating a display panel, comprising the following steps: providing a substrate, wherein a plurality of light-emitting device layers are disposed on the substrate; sequentially forming a first inorganic encapsulation layer and an organic encapsulation layer on the plurality of light-emitting device layers; providing a transfer substrate, the transfer substrate including a first protrusion and a second protrusion, the first protrusion and the second protrusion being interconnected, and the height of the first protrusion being greater than the height of the second protrusion; pressing one side of the transfer substrate having the first protrusion and the second protrusion toward the organic encapsulation layer, such that the side of the organic encapsulation layer opposite to the substrate forms a recessed pattern complementary to the first protrusion and the second protrusion, wherein the first protrusion... A first recess is formed at a corresponding position of the first part, and a second recess is formed at a corresponding position of the second protrusion, wherein the depth of the first recess is greater than the depth of the second recess; the transfer substrate is removed; a second inorganic encapsulation layer and a color filter layer are sequentially formed on the organic encapsulation layer, wherein the color filter layer fills the recess pattern, and the surface of the color filter layer facing away from the substrate is a flat surface; wherein the color filter layer includes color resist blocks of multiple colors, the area between the first recess and the light-emitting device layer is correspondingly disposed, and the first recess is filled with a stacked structure of at least two different colors of color resist blocks; the second recess is correspondingly disposed with respect to the light-emitting device layer, and the second recess is filled with a color resist block of a single color.

[0006] In one exemplary embodiment of this application, the organic encapsulation layer is cured after the side of the transfer substrate having the first protrusion and the second protrusion is pressed against the organic encapsulation layer.

[0007] In one exemplary embodiment of this application, the fabrication of the transfer substrate includes: providing a transparent substrate; forming a patterned color resist layer on the transparent substrate, the patterned color resist layer having a first protrusion and a second protrusion connected to each other, the height of the first protrusion being greater than the height of the second protrusion, wherein the first protrusion corresponds to the region between the light-emitting device layers, and the second protrusion corresponds to the light-emitting device layer; forming an inorganic layer on the patterned color resist layer; and forming a sacrificial layer on the inorganic layer.

[0008] In one exemplary embodiment of this application, the step of removing the transfer substrate includes: irradiating the transparent substrate with a laser to decompose the sacrificial layer, thereby separating the transfer substrate from the organic encapsulation layer.

[0009] In one exemplary embodiment of this application, the fabrication of the transfer substrate includes: providing a transparent substrate; forming a rigid layer on the transparent substrate, the rigid layer including a first protrusion and a second protrusion connected to each other, wherein the height of the first protrusion is greater than the height of the second protrusion; and forming an inorganic layer on the rigid layer.

[0010] In one exemplary embodiment of this application, the organic encapsulation layer is partially cured before the side of the transfer substrate having the first protrusion and the second protrusion is pressed against the organic encapsulation layer.

[0011] In an exemplary embodiment of this application, the formation of the interconnected first and second protrusions in the rigid layer includes: forming a rigid material layer on the transparent substrate; forming a patterned color resist layer on the rigid material layer, the patterned color resist layer having interconnected first and second initial protrusions, the height of the first initial protrusion being greater than the height of the second initial protrusion, wherein the first initial protrusion corresponds to the region between the light-emitting device layers, and the second initial protrusion corresponds to the light-emitting device layer; etching the patterned color resist layer and the rigid material layer using a dry etching process, utilizing the etching rate difference of different thickness regions of the patterned color resist layer to replicate the uneven morphology of the patterned color resist layer to the rigid material layer, so that the rigid material layer forms interconnected first and second protrusions, and the height of the first protrusion is greater than the height of the second protrusion.

[0012] In one exemplary embodiment of this application, after pressing the side of the transfer substrate having the first protrusion and the second protrusion onto the organic encapsulation layer, the organic encapsulation layer is completely cured.

[0013] A second aspect of this application provides a display panel, comprising: a substrate on which a plurality of light-emitting device layers are disposed; a first inorganic encapsulation layer disposed on the plurality of light-emitting device layers; an organic encapsulation layer disposed on the first inorganic encapsulation layer, the organic encapsulation layer having a recessed pattern on a side facing away from the substrate, the recessed pattern including a first recess and a second recess, wherein the depth of the first recess is greater than the depth of the second recess; a second inorganic encapsulation layer disposed on the organic encapsulation layer; and a color filter layer disposed on the second inorganic encapsulation layer, the color filter layer filling the recessed pattern, and the surface of the color filter layer facing away from the substrate being a flat surface; wherein the color filter layer includes color resist blocks of multiple colors, the area between the first recess and the light-emitting device layers is correspondingly disposed, the first recess being filled with a stacked structure of at least two different colors of color resist blocks; the second recess being correspondingly disposed with the light-emitting device layers, the second recess being filled with a color resist block of a single color.

[0014] In one exemplary embodiment of this application, the stacked structure of color resist blocks of at least two different colors includes at least two of red color resist blocks, green color resist blocks, and blue color resist blocks.

[0015] The method for manufacturing the display panel and the display panel described in this application have at least the following beneficial effects:

[0016] The method for fabricating a display panel provided in this application involves providing a transfer substrate with a first protrusion and a second protrusion, wherein the height of the first protrusion is greater than the height of the second protrusion. The side of the transfer substrate with the protrusion is pressed against an organic encapsulation layer, causing the organic encapsulation layer to form a recessed pattern complementary to the protrusion. The first protrusion corresponds to a first recess with a greater depth, and the second protrusion corresponds to a second recess with a smaller depth. Based on this, at least two different colors of color resist stacked structures are correspondingly disposed and filled in the area between the first recess and the light-emitting device layer, and a single-color color resist is correspondingly disposed and filled in the second recess and the light-emitting device layer. Since the depth of the first recess matches the thickness of the color resist stacked structure, and the depth of the second recess matches the thickness of the single-color color resist, the surface of the color filter layer is naturally flat after filling the recessed pattern, eliminating the need for an additional flattening layer. Therefore, this application improves the problem that the surface of the color filter layer is uneven due to the replacement of the black matrix structure with color resist stacking, which requires an additional planarization layer. It effectively reduces the overall thickness of the display panel, improves the bending performance of the panel, reduces light loss caused by light passing through the planarization layer, improves light extraction efficiency, simplifies the manufacturing process, and reduces production costs.

[0017] Other features and advantages of this application will become apparent from the following detailed description, or may be learned in part from practice of this application.

[0018] It should be understood that the above general description and the following detailed description are exemplary and explanatory only, and do not limit this application. Attached Figure Description

[0019] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0020] Figure 1 A schematic diagram of a method for manufacturing a display panel is shown.

[0021] Figure 2 It shows Figure 1A schematic diagram of the structural process of the method for manufacturing a display panel.

[0022] Figure 3 The preparation is shown Figure 2 A schematic diagram of the fabrication process of the transfer substrate for the display panel.

[0023] Figure 4 It shows Figure 3 A schematic diagram of the structural process of the fabrication method of the transfer substrate.

[0024] Figure 5 A schematic diagram of another method for manufacturing a display panel is shown.

[0025] Figure 6 It shows Figure 5 A schematic diagram of the structural process of the method for manufacturing a display panel.

[0026] Figure 7 The preparation is shown Figure 6 A schematic diagram of the fabrication process of the transfer substrate for the display panel.

[0027] Figure 8 It shows Figure 7 A schematic diagram of the structural process of the fabrication method of the transfer substrate.

[0028] Figure 9 It shows the use of Figure 1 A schematic diagram of the process for fabricating a display panel and a schematic diagram of the structure of the resulting display panel.

[0029] Figure 10 It shows the use of Figure 5 A schematic diagram of the process for fabricating a display panel and a schematic diagram of the structure of the resulting display panel.

[0030] Explanation of reference numerals in the attached figures:

[0031] 100, Display panel; 110, Substrate; 120, Light-emitting device layer; 121, First light-emitting device layer; 122, Second light-emitting device layer; 123, Third light-emitting device layer; 130, First inorganic encapsulation layer; 140, Organic encapsulation layer; 141, Recessed pattern; 141a, First recess; 141b, Second recess; 200, Transfer substrate; 210, Transparent substrate; 220, Patterned color resist layer; 221, First protrusion; 222, Second protrusion; 230, Inorganic layer; 240, Sacrificial layer; 250, Rigid layer; 251, Rigid material layer; 300, Second inorganic encapsulation layer; 400, Color filter layer; 410, Color resist block; 411, Red color resist block; 412, Green color resist block; 413, Blue color resist block. Detailed Implementation

[0032] Exemplary embodiments will now be described more fully with reference to the accompanying drawings. However, these exemplary embodiments can be implemented in many forms and should not be construed as limited to the examples set forth herein; rather, these embodiments are provided to make this application more comprehensive and complete, and to fully convey the concept of the exemplary embodiments to those skilled in the art.

[0033] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, "multiple" means two or more, unless otherwise explicitly specified.

[0034] In this application, unless otherwise expressly specified and limited, the terms "assembly," "connection," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0035] Furthermore, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. Numerous specific details are provided in the following description to give a thorough understanding of embodiments of this application. However, those skilled in the art will recognize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, apparatuses, steps, etc., can be employed. In other instances, well-known methods, apparatuses, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0036] Example 1

[0037] See Figure 1 and Figure 2 As shown, this embodiment provides a method for manufacturing a display panel 100, which specifically includes the following steps:

[0038] Step S100a: Provide substrate 110.

[0039] A plurality of light-emitting device layers 120 are disposed on a substrate 110. The substrate 110 can be a flexible substrate 110, such as a polyimide (PI) substrate 110, or a rigid substrate 110, such as a glass substrate 110. The plurality of light-emitting device layers 120 include a first light-emitting device layer 121, a second light-emitting device layer 122, and a third light-emitting device layer 123 with different emission colors, such as a red light-emitting device layer, a green light-emitting device layer, and a blue light-emitting device layer. Each light-emitting device layer 120 includes an anode, an organic emitting layer, and a cathode, wherein the anode can be controlled by a thin-film transistor (TFT) driving circuit. The TFT driving circuit includes an active layer, a gate, a source, a drain, and various insulating layers, the specific structure of which is well known to those skilled in the art and will not be described in detail here.

[0040] Step S200a: A first inorganic encapsulation layer 130 and an organic encapsulation layer 140 are formed.

[0041] A first inorganic encapsulation layer 130 and an organic encapsulation layer 140 are sequentially formed on multiple light-emitting device layers 120. The first inorganic encapsulation layer 130 can be formed using a chemical vapor deposition (CVD) process, and the material can be selected from one or more of silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiON), with a thickness of approximately 0.5 μm to 1 μm. The function of the first inorganic encapsulation layer 130 is to block water and oxygen, protecting the underlying light-emitting device layer 120.

[0042] The organic encapsulation layer 140 can be formed using inkjet printing, spin coating, or slot coating processes. The material can be selected from organic materials such as acrylic resins, epoxy resins, or polyimides, and its thickness is approximately 5 μm to 10 μm. The organic encapsulation layer 140 serves to provide a planarization base and as a carrier for subsequent imprinting patterning. The organic encapsulation layer 140 is initially in a liquid or semi-fluid state, facilitating imprinting patterning.

[0043] It should be noted that the organic encapsulation layer 140 can be made of photosensitive polyimide or photosensitive acrylic resin. These materials can be directly cured under ultraviolet (UV) irradiation without the need for additional photoinitiators, which simplifies the manufacturing process. Furthermore, the thickness of the organic encapsulation layer 140 can be adjusted according to actual needs. For example, for a high-resolution display panel 100, the thickness of the organic encapsulation layer 140 can be appropriately reduced to decrease the overall panel thickness.

[0044] Step S300a: Provide transfer substrate 200.

[0045] The transfer substrate 200 has a first protrusion 221 and a second protrusion 222 on the side facing the organic encapsulation layer 140. The first protrusion 221 and the second protrusion 222 are connected to each other, and the height of the first protrusion 221 is greater than the height of the second protrusion 222. (See also...) Figure 3and Figure 4 As shown, the specific fabrication method of the transfer substrate 200 is as follows:

[0046] Step S310a: Provide a transparent substrate 210.

[0047] The substrate can be, for example, a glass substrate or a quartz substrate. The transparent substrate 210 has good light transmittance, which facilitates subsequent laser lift-off processes.

[0048] Step S320a: A patterned color resist layer 220 is formed on the transparent substrate 210.

[0049] The patterned color resist layer 220 is formed by sequentially depositing color resist blocks 410 of different colors. For example, red color resist block 411, green color resist block 412 and blue color resist block 413 are deposited sequentially in the reverse order of the target color filter layer 400.

[0050] For example, if the process sequence of the target color filter layer is blue, green, red (BGR), then the process sequence of the patterned color resist layer 220 on the transfer substrate 200 is red, green, blue (RGB), to ensure that the morphology of the transfer substrate 200 and the thickness distribution of the target color filter layer 400 are inverted complementary. During the deposition process, the number of color resist layers deposited in different regions is different through mask design.

[0051] In the region between the corresponding light-emitting device layers 120 (i.e., the non-light-emitting region), multiple layers of color resist blocks 410 of different colors are sequentially deposited, for example, red color resist block 411, green color resist block 412 and blue color resist block 413 are sequentially deposited to form a three-layer color resist stacked structure. This region is the first protrusion 221. Due to the three-layer color resist stack, the first protrusion 221 has a relatively high height.

[0052] In the corresponding light-emitting device layer 120 (i.e., the light-emitting area), only a single color resist block 410 is deposited, such as only a red resist block 411, only a green resist block 412, or only a blue resist block 413. This area is the second protrusion 222. Because only a single layer of resist is deposited, the height of the second protrusion 222 is relatively low.

[0053] It should be noted that the individual color resists can also have different thicknesses. That is, the thickness of the single-layer color resist blocks 410 corresponding to different light-emitting areas can be set differently. For example, the luminous intensity of the green sub-pixel is usually higher than that of the red and blue sub-pixels. To balance the light extraction efficiency of different color sub-pixels, the thickness of the color resist block 410 corresponding to the green sub-pixel can be set to be less than the thickness of the color resist blocks 410 corresponding to the red and blue sub-pixels. Correspondingly, the height of the second protrusion 222 on the transfer substrate 200 corresponding to the green light-emitting area is also less than the height of the second protrusion 222 corresponding to the red or blue light-emitting area. This design results in differences in the thickness of the single-layer color resists in different color light-emitting areas of the final color filter layer 400, thereby balancing the light extraction efficiency and improving the display effect.

[0054] Thus, the patterned color resist layer 220 forms interconnected first protrusions 221 and second protrusions 222, with the height of the first protrusion 221 being greater than the height of the second protrusion 222. The height difference between the first protrusion 221 and the second protrusion 222 is the thickness difference between the multilayer color resist stack and the single-layer color resist. This height difference matches the thickness difference between the non-emitting and emitting areas in the subsequent color filter layer 400. For example, when the thickness of the non-emitting area color resist stack is approximately three times the thickness of the single-layer color resist in the emitting area, the height difference between the first protrusion 221 and the second protrusion 222 is approximately twice the thickness of the single-layer color resist.

[0055] Step S330a: An inorganic layer 230 is formed on the patterned color resist layer 220.

[0056] The inorganic layer 230 can be formed using a chemical vapor deposition (CVD) process. The material is the same as that of the subsequent second inorganic encapsulation layer 300, such as silicon nitride (SiNx). The thickness of the inorganic layer 230 is consistent with the thickness of the second inorganic encapsulation layer 300, such as 0.5 μm to 1 μm, to ensure that the structure on the transfer substrate 200 is completely complementary to the structure finally formed on the OLED.

[0057] It should be noted that the inorganic layer 230 on the transfer substrate 200 only needs to ensure that its thickness is consistent with that of the second inorganic encapsulation layer 300. Its film quality (such as water and oxygen barrier properties) is not subject to special requirements, because the inorganic layer 230 will be removed along with the transfer substrate 200 after the transfer substrate 200 is peeled off and will not be retained in the display panel 100.

[0058] Step S340a: A sacrificial layer 240 is formed on the inorganic layer 230.

[0059] The sacrificial layer 240 can be made of materials such as gallium nitride (GaN) and has a thickness of 0.1 μm to 1 μm. The sacrificial layer 240 will decompose under laser irradiation of a specific wavelength, which facilitates the subsequent peeling off of the transfer substrate 200.

[0060] It is worth mentioning that the thickness of the sacrificial layer 240 should be as thin as possible (e.g., 0.1μm to 0.5μm) to reduce the overall thickness of the display panel 100 while ensuring sufficient decomposition efficiency. Gallium nitride (GaN) material has strong absorption characteristics for lasers with wavelengths of 256nm or 308nm, and can decompose rapidly under laser irradiation. During laser irradiation, the surface portion of the sacrificial layer 240 absorbs most of the laser energy, causing the decomposition to occur on the side closer to the laser irradiation, thereby ensuring that the sacrificial layer 240 is peeled off from the transfer substrate 200 side, leaving very little residue on the OLED panel.

[0061] Furthermore, the material of the sacrificial layer 240 is not limited to gallium nitride (GaN); other materials that decompose under specific wavelength laser irradiation, such as polymethyl methacrylate (PMMA), can also be used. PMMA undergoes a depolymerization reaction under ultraviolet laser irradiation, decomposing into gaseous monomers, which can also achieve non-destructive peeling. The selection of different sacrificial layer 240 materials can be optimized according to process requirements such as laser wavelength and peeling speed.

[0062] Through the above steps, a transfer substrate 200 with a first protrusion 221 and a second protrusion 222 can be obtained. The morphology of the transfer substrate 200 is inverted and complementary to the thickness distribution of the target color filter layer 400. The first protrusion 221 (higher, formed by stacking multiple layers of color resist) on the transfer substrate 200 corresponds to the non-light-emitting area (thicker) in the subsequent color filter layer 400, and the second protrusion 222 (lower, formed by a single layer of color resist) corresponds to the light-emitting area (thinner) in the subsequent color filter layer 400. This inverted relationship ensures that the recessed pattern 141 formed by the organic encapsulation layer 140 after imprinting matches the thickness distribution of the color filter layer 400.

[0063] Step S400a, Imprinting process.

[0064] The transfer substrate 200, with the first protrusion 221 and the second protrusion 222 on one side, is pressed against the organic encapsulation layer 140. At this time, the organic encapsulation layer 140 is not yet solidified and is still in a liquid or semi-fluid state, so the protrusions on the transfer substrate 200 can be pressed into the organic encapsulation layer 140. During imprinting, the pressure needs to be controlled to ensure that the thinnest film layer on the transfer substrate 200 (i.e., the second protrusion 222) is also completely pressed into the organic encapsulation layer 140, that is, the second protrusion 222 must be completely embedded in the organic encapsulation layer 140 to ensure that an effective recessed pattern 141 can be formed in all areas. At the same time, excessive pressure should be avoided to prevent the organic encapsulation layer 140 from being over-extruded. For example, the imprinting pressure is generally controlled between 0.1 MPa and 0.5 MPa.

[0065] After imprinting, the organic encapsulation layer 140 is cured. In this embodiment, ultraviolet (UV) light is used to cure the organic encapsulation layer 140. UV light can be applied from one side of the transfer substrate 200 (the transparent substrate 210 allows UV light to pass through), from one side of the substrate 110, or simultaneously from both sides to accelerate the curing process. After curing, the organic encapsulation layer 140 changes from a liquid to a solid state while retaining the pattern formed by imprinting.

[0066] Understandably, during the imprinting process, the transfer substrate 200 and / or the organic encapsulation layer 140 can be heated to reduce the viscosity of the organic encapsulation layer 140 and improve the patterning quality. The heating temperature is generally controlled between 50°C and 100°C. Furthermore, a release agent, such as a fluorocarbon compound, can be applied to the surface of the transfer substrate 200 to reduce adhesion during peeling and improve the reusability of the transfer substrate 200.

[0067] After curing, the organic encapsulation layer 140 forms a recessed pattern 141 on the side facing away from the substrate 110, complementary to the first protrusion 221 and the second protrusion 222. A first recess 141a is formed at a position corresponding to the first protrusion 221 (higher), and a second recess 141b is formed at a position corresponding to the second protrusion 222 (lower), with the depth of the first recess 141a greater than the depth of the second recess 141b. Since the first protrusion 221 corresponds to a non-light-emitting area and the second protrusion 222 corresponds to a light-emitting area, the first recess 141a corresponds to the non-light-emitting area, and the second recess 141b corresponds to the light-emitting area. The depth of the first recess 141a is approximately equal to the height of the first protrusion 221, and the depth of the second recess 141b is approximately equal to the height of the second protrusion 222.

[0068] Step S500a: Remove the transfer substrate 200.

[0069] The transfer substrate 200 is removed using a laser lift-off method. A laser is irradiated from one side of the transparent substrate 210, with the laser wavelength selectable as 256 nm or 308 nm. Gallium nitride (GaN) material has extremely strong absorption capabilities for this wavelength of laser light. During laser irradiation, the surface portion of the sacrificial layer 240 absorbs most of the laser energy and decomposes. The decomposition occurs near the side closest to the laser irradiation, allowing the sacrificial layer 240 to be peeled off from the transfer substrate 200 side without damaging the underlying organic encapsulation layer 140.

[0070] During laser stripping, the laser energy density needs to be controlled to ensure that the sacrificial layer 240 is completely decomposed without damaging the underlying organic encapsulation layer 140. Because gallium nitride (GaN) has extremely strong absorption of laser light, most of the laser energy is absorbed by the sacrificial layer 240, thus having little impact on the organic encapsulation layer 140.

[0071] Understandably, the stripped transfer substrate 200 can be recycled; it can be reused simply by re-fabricating the sacrificial layer 240, inorganic layer 230, and patterned color resist layer 220. This significantly reduces production costs and improves material utilization. To facilitate reuse, the transparent substrate 210 of the transfer substrate 200 should be made of a laser-resistant material, such as quartz glass.

[0072] Step S600a: Form the second inorganic encapsulation layer 300 and the color filter layer 400.

[0073] A second inorganic encapsulation layer 300 and a color filter layer 400 are sequentially formed on the organic encapsulation layer 140. The second inorganic encapsulation layer 300 can be formed using the same chemical vapor deposition (CVD) process as the first inorganic encapsulation layer 130, and the material can be selected from silicon nitride (SiNx) or silicon oxide (SiOx), with a thickness of approximately 0.5 μm to 1 μm. The function of the second inorganic encapsulation layer 300 is to further block water and oxygen and protect the underlying organic encapsulation layer 140.

[0074] The color filter layer 400 fills the recessed pattern 141, and the surface of the color filter layer 400 facing away from the substrate 110 is a flat surface. For example, the color filter layer 400 may include color resist blocks 410 of multiple colors, such as red color resist block 411, green color resist block 412, and blue color resist block 413. The first recess 141a (corresponding to the non-emitting area) is filled with a stacked structure of at least two different colors of color resist blocks 410, such as a red and green stack, a red and blue stack, a green and blue stack, or a red-green-blue three-layer stack. Because the first recess 141a has a relatively large depth, it can accommodate multiple layers of color resist stacks, and this depth matches the thickness of the multiple layers of color resist stacks. The second recess 141b (corresponding to the emitting area) is filled with a single color resist block 410, such as red, green, or blue. Because the second recess 141b has a smaller depth, it can only accommodate a single layer of color resist, and this depth matches the thickness of the single layer of color resist.

[0075] The color filter layer 400 can be formed using inkjet printing or photolithography. Taking photolithography as an example, a red color resist 411, a green color resist 412, and a blue color resist 413 can be formed sequentially. When forming each color resist 410, the mask design ensures that the color resist 410 is deposited only in the second recess 141b of the corresponding light-emitting area and the first recess 141a of the non-light-emitting area that needs to be stacked. For example, when forming the red color resist 411, a single layer of red color resist 411 is deposited in the second recess 141b corresponding to the red light-emitting area, and simultaneously, a red color resist 411 is also deposited in the first recess 141a of the non-light-emitting area that needs to be stacked; when forming the green color resist 412, a single layer of green color resist 412 is deposited in the second recess 141b corresponding to the green light-emitting area, and simultaneously, a green color resist 412 is also deposited in the first recess 141a of the non-light-emitting area that needs to be stacked; the same applies when forming the blue color resist 413. Finally, in the first recess 141a of the non-luminescent area, multiple layers of color resist blocks 410 of different colors are deposited to form a light-blocking structure; in the second recess 141b of the luminescent area, a single-color color resist block 410 is deposited to form a light-filtering structure.

[0076] It should be noted that different stacking orders can be set in the multi-layer color resist stacking in the non-light-emitting area. For example, when red color resist block 411, green color resist block 412, and blue color resist block 413 are stacked, the light-blocking effect can be optimized by adjusting the stacking order. Tests have shown that different stacking orders have little impact on the light-blocking effect, but the process can be chosen according to the convenience of the manufacturing process. For example, blue color resist block 413 can be formed first, then green color resist block 412, and finally red color resist block 411. In addition, the number of stacked color resist blocks 410 is not limited to two or three layers, but can also be four or more layers, such as adding yellow color resist block 410, to enhance the light-blocking effect or achieve other optical functions.

[0077] Because the recessed pattern 141 on the organic encapsulation layer 140 is complementary to the thickness distribution of the color filter layer 400—that is, the non-light-emitting area is recessed deeper to accommodate a thicker stack of multiple color resist layers, while the light-emitting area is recessed shallower to accommodate a thinner single layer of color resist—the surface of the color filter layer 400 is naturally flat after filling, eliminating the need for an additional planarization layer. This structural design cleverly solves the problem that would otherwise require an additional planarization layer by pre-solving it through an imprinting process, achieving self-planarization.

[0078] It is worth noting that the widths of the first and second protrusions on the transfer substrate do not necessarily have to be the same, nor do the widths of individual color resist blocks necessarily have to be identical. The widths of the first and second protrusions, as well as the widths of each color resist block, should be adaptively set according to the pixel arrangement of the display panel and the dimensions of different color light-emitting device layers. For example, the pixel arrangement of OLED display panels includes various methods such as strip arrangement and diamond arrangement, and the opening sizes of each color light-emitting device layer differ under different arrangement methods. For example, the luminous efficiency of the blue light-emitting device layer is relatively low, and its opening size is usually set larger to balance the light emission efficiency; the luminous efficiency of the green light-emitting device layer is relatively the highest, and its opening size is usually set smaller; the opening size of the red light-emitting device layer is between the two. Accordingly, the dimensions of the color resist blocks corresponding to each light-emitting device layer in the color filter layer mentioned below should match the opening size of the light-emitting device layer, that is, the width of the blue color resist block is greater than the width of the red color resist block, and the width of the red color resist block is greater than the width of the green color resist block. Based on this, the width of the second protrusion on the transfer substrate corresponding to each color resist block is also set accordingly. That is, the width of the second protrusion corresponding to the blue color resist block is the largest, the width of the second protrusion corresponding to the red color resist block is the second largest, and the width of the second protrusion corresponding to the green color resist block is the smallest. Similarly, the width of the first protrusion (corresponding to the non-light-emitting area) should also be designed according to the actual size of the non-light-emitting area. Through the above design, the morphology of the transfer substrate can be precisely matched with the actual thickness and size distribution of the color filter layer, further improving the accuracy of imprinting patterning and the display effect of the final product.

[0079] The preparation method of this embodiment effectively improves the problem that the surface of the color filter layer 400 is uneven due to the replacement of the BM structure with RGB color resist stacking, which requires an additional planarization layer. It significantly reduces the overall thickness of the display panel 100, improves bending performance, reduces light loss caused by light passing through the planarization layer, improves light extraction efficiency, simplifies the process, and reduces production costs.

[0080] Example 2

[0081] See Figure 5 and Figure 6 As shown, this embodiment provides another method for manufacturing a display panel 100. The main difference from Embodiment 1 lies in the structure of the transfer substrate 200, the formation method of the protrusions, and the removal method. This embodiment aims to further optimize the process, reduce the use of the sacrificial layer 240, realize the direct reuse of the transfer substrate 200, and improve the patterning accuracy.

[0082] Step S100b: Provide substrate 110 and form encapsulation layer.

[0083] This step is the same as in Embodiment 1, providing a substrate 110, on which multiple light-emitting device layers 120 are disposed, and a first inorganic encapsulation layer 130 and an organic encapsulation layer 140 are formed sequentially. Further details are omitted here.

[0084] Step S200b: Provide transfer substrate 200.

[0085] In this embodiment, the transfer substrate 200 includes a rigid layer 250. The rigid layer 250 has a first protrusion 221 and a second protrusion 222 that are connected to each other, and the height of the first protrusion 221 is greater than the height of the second protrusion 222. See also Figure 7 and Figure 8 As shown, the specific preparation method is as follows:

[0086] Step S210b: Provide a transparent substrate 210, such as a glass substrate. Form a rigid material layer 251 on the transparent substrate 210. The rigid material layer 251 can be an inorganic layer 230 or a metal layer, such as silicon nitride (SiNx), silicon oxide (SiOx), aluminum (Al), molybdenum (Mo), etc. Its thickness is greater than the maximum thickness difference of the color filter layer 400. For example, if the difference between the RGB stack thickness of the non-light-emitting area and the single-layer color resist thickness of the light-emitting area in the color filter layer 400 is Δh, then the thickness of the rigid material layer 251 should be greater than Δh, which can be 2μm to 5μm, to ensure that the uneven morphology of the color resist layer can be completely replicated during the dry etching process.

[0087] In other embodiments, the rigid layer 250 can be made of metal or alloy, such as aluminum (Al), molybdenum (Mo), titanium (Ti), etc. Metal materials have better mechanical strength and thermal conductivity, which is beneficial to improving the accuracy and consistency of the embossed pattern. At the same time, the thermal conductivity of metal materials helps to control the temperature during the embossing process.

[0088] Step S220b: A patterned color resist layer 220 is formed on the rigid material layer 251.

[0089] The patterned color resist layer 220 is formed in the same manner as in Embodiment 1, by sequentially depositing color resist blocks 410 of different colors. It has a first initial protrusion and a second initial protrusion that are interconnected, and the height of the first initial protrusion is greater than the height of the second initial protrusion. The first initial protrusion corresponds to the region between the light-emitting device layers 120 (non-light-emitting region), and the second initial protrusion corresponds to the light-emitting device layer 120 (light-emitting region).

[0090] In step S230b, the patterned color resist layer 220 and the rigid material layer 251 are etched using a dry etching process.

[0091] Dry etching processes can employ reactive ion etching (RIE) or inductively coupled plasma etching (ICP). The etching gas can be selected according to the material. For example, O2 or a mixture of O2 and Cl2 can be used to etch organic color resist layers, while CF4, SF6, or Cl2 can be used to etch inorganic rigid layers.

[0092] For example, a mixture of O2 and Cl2 gas is used for dry etching. During the dry etching process, due to the different etching rates in different thickness areas of the patterned color resist layer 220, the thinner areas (second initial protrusions) of the color resist layer are completely etched away first, exposing the underlying rigid material layer 251, which then begins etching. The thicker areas (first initial protrusions) of the color resist layer are etched more slowly, protecting the underlying rigid material layer 251. After all color resist layers have been etched, a concave-convex structure corresponding to the original color resist layer morphology is formed on the rigid material layer 251, namely, the interconnected first protrusion 221 and second protrusion 222, with the height of the first protrusion 221 being greater than the height of the second protrusion 222. This process utilizes the etching selectivity between the color resist layer and the rigid material layer 251 to achieve precise morphology transfer.

[0093] Understandably, in dry etching processes, the etching rate can be precisely controlled by adjusting parameters such as the proportion of etching gas, etching power, and pressure, thereby achieving fine-grained control over the height and shape of the protrusions. For example, increasing the O2 ratio can improve the etching rate of organic color resist layers, while increasing the Cl2 ratio can improve the etching rate of inorganic rigid layer 250. By optimizing etching parameters, protrusion structures with steeper sidewalls can be obtained.

[0094] In step S240b, an inorganic layer 230 is formed on the rigid layer 250. This inorganic layer 230 protects the rigid layer 250 and contacts the organic encapsulation layer 140 during subsequent imprinting. The inorganic layer 230 can be formed using a chemical vapor deposition (CVD) process, and the material can be selected from silicon nitride (SiNx) or silicon oxide (SiOx), with a thickness of approximately 0.5 μm to 1 μm.

[0095] Through the above steps, a transfer substrate 200 with a rigid layer 250 protrusion structure can be obtained. This solution eliminates the need for a sacrificial layer 240, simplifying the process. Furthermore, the rigid layer 250 possesses good mechanical strength, is less prone to deformation during imprinting, and achieves higher patterning accuracy. Simultaneously, since there is no sacrificial layer 240 between the rigid layer 250 and the organic encapsulation layer 140, laser irradiation is unnecessary during peeling, reducing the potential impact of laser on the organic encapsulation layer 140.

[0096] Step S300b: Partial curing and imprinting.

[0097] Before pressing the side of the transfer substrate 200 with the first protrusion 221 and the second protrusion 222 onto the organic encapsulation layer 140, the organic encapsulation layer 140 is partially cured, causing it to change from a liquid state to a soft solid state. Partial curing can be achieved by controlling the ultraviolet (UV) irradiation time or heating temperature, for example, by irradiating with ultraviolet (UV) light for 5 to 10 seconds, so that the organic encapsulation layer 140 reaches a gel state. At this time, the organic encapsulation layer 140 retains a certain degree of deformability but does not have fluidity, making it easy to imprint and less prone to flow and adhesion.

[0098] It should be noted that the degree of partial curing can be precisely controlled by curing time or temperature. Excessive partial curing will result in the organic encapsulation layer 140 being too hard, making it difficult to form a clear recessed pattern 141 during imprinting; insufficient partial curing will leave the organic encapsulation layer 140 still fluid, easily causing overflow during imprinting. Therefore, the optimal partial curing conditions need to be determined experimentally based on the material properties of the organic encapsulation layer 140.

[0099] The transfer substrate 200 is then pressed against the partially cured organic encapsulation layer 140. Since the organic encapsulation layer 140 is a soft solid, the rigid protrusions on the transfer substrate 200 can be effectively pressed into the organic encapsulation layer 140 during imprinting, forming a clear recessed pattern 141. The imprinting pressure can be adjusted according to the hardness of the organic encapsulation layer 140, and is generally controlled between 0.1 MPa and 0.5 MPa.

[0100] After imprinting, the organic encapsulation layer 140 is completely cured, for example by irradiating with ultraviolet (UV) light for 30 to 60 seconds or heating to 100°C to 150°C, so that the organic encapsulation layer 140 is completely cured and shaped.

[0101] After curing, the organic encapsulation layer 140 forms a recessed pattern 141 on the side opposite to the substrate 110, which is complementary to the first protrusion 221 and the second protrusion 222. The first protrusion 221 forms a first recess 141a with a larger depth, and the second protrusion 222 forms a second recess 141b with a smaller depth.

[0102] Step S400b: Remove the transfer substrate 200.

[0103] The transfer substrate 200 and the organic encapsulation layer 140 are mechanically separated by external force. Since the organic encapsulation layer 140 is partially cured before imprinting and fully cured after imprinting, and no sacrificial layer 240 is provided on the transfer substrate 200, there is no strong adhesion between the two. Therefore, the transfer substrate 200 can be directly removed by mechanical peeling without laser irradiation. During peeling, a vacuum suction cup can be used to adsorb the transfer substrate 200, and a vertical pulling force can be applied for easy separation.

[0104] Understandably, the removed transfer substrate 200 can be reused; it only requires surface cleaning and can be reused without the need to re-prepare any film layers, further reducing production costs. To ensure the accuracy of reuse, the cleaning process should employ methods that do not damage the surface of the rigid layer 250, such as plasma cleaning or solvent cleaning.

[0105] Step S500b forms a second inorganic encapsulation layer 300 and a color filter layer 400.

[0106] This step is the same as in Embodiment 1, in which a second inorganic encapsulation layer 300 and a color filter layer 400 are sequentially formed on the organic encapsulation layer 140. Since a recessed pattern 141 complementary to the thickness distribution of the color filter layer 400 has been formed on the organic encapsulation layer 140, the surface of the color filter layer 400 is naturally flat after filling, and no additional flattening layer is required.

[0107] This embodiment achieves a sacrificial layer 240-free peeling process by using a rigid layer 250 to transfer the protrusion morphology and by partially curing the organic encapsulation layer 140 before imprinting. This further simplifies the process, reduces costs, and enables the reuse of the transfer substrate 200. Furthermore, the rigid layer 250 transfer method can achieve a higher precision protrusion morphology, which is beneficial for realizing a higher resolution display panel 100.

[0108] Example 3

[0109] See Figure 9 or Figure 10 As shown, a display panel 100 can be obtained by the preparation method of any of the above embodiments, and its structure is as follows:

[0110] The display panel 100 includes a substrate 110, on which a plurality of light-emitting device layers 120 are disposed. A first inorganic encapsulation layer 130 is disposed on the plurality of light-emitting device layers 120. An organic encapsulation layer 140 is disposed on the first inorganic encapsulation layer 130, and the organic encapsulation layer 140 has a recessed pattern 141 on the side facing away from the substrate 110. The recessed pattern 141 includes a first recess 141a and a second recess 141b, and the depth of the first recess 141a is greater than the depth of the second recess 141b. A second inorganic encapsulation layer 300 is disposed on the organic encapsulation layer 140. A color filter layer 400 is disposed on the second inorganic encapsulation layer 300, and the color filter layer 400 fills the recessed pattern 141, and the surface of the color filter layer 400 facing away from the substrate 110 is a flat surface.

[0111] The color filter layer 400 includes color resist blocks 410 of multiple colors. The area between the first recess 141a and the light-emitting device layer 120 is correspondingly disposed. The first recess 141a is filled with a stacked structure of at least two different colors of color resist blocks 410, such as at least two of the following: red color resist block 411, green color resist block 412, and blue color resist block 413. The second recess 141b is correspondingly disposed with the light-emitting device layer 120. The second recess 141b is filled with a color resist block 410 of a single color, such as red, green, or blue.

[0112] It is understood that the stacked structure of at least two different colored color resist blocks 410 can include a stack of red color resist block 411 and green color resist block 412, a stack of red color resist block 411 and blue color resist block 413, a stack of green color resist block 412 and blue color resist block 413, or a three-layer stack of red color resist block 411, green color resist block 412 and blue color resist block 413. The stacking order of different colors can be adjusted according to process requirements, for example, from bottom to top, red, green, blue, or blue, green, red, etc.

[0113] Furthermore, touch functionality can be integrated into the display panel 100. For example, a touch electrode layer can be positioned above or below the color filter layer 400. This touch electrode layer can employ a mesh-like metal structure and be positioned in the corresponding non-light-emitting area to avoid affecting light extraction efficiency. The touch electrode layer can be implemented using existing Flexible Multi-Layer On Cell (FMLOC) technology, sharing some manufacturing processes with the color filter layer 400, further reducing thickness and cost.

[0114] It is worth mentioning that, due to its thinner thickness and better bending performance, the display panel 100 of this application is particularly suitable for foldable display devices. In foldable display devices, the display panel 100 needs to be bent frequently, and a thinner thickness and better bending performance can extend the lifespan of the device. The technical solution of this application reduces the thickness of the display panel 100 and decreases the bending radius by eliminating an additional planarization layer, making it more suitable for foldable applications.

[0115] Because the display panel 100 uses the above-mentioned manufacturing method, its color filter layer 400 has a naturally flat surface, eliminating the need for an additional flattening layer. As a result, the overall thickness is thinner, the bending performance is better, the light extraction efficiency is higher, and the manufacturing process is simpler and the cost is lower.

[0116] The display panel 100 and its manufacturing method provided in this application form a recessed pattern 141 on the organic encapsulation layer 140 that is complementary to the thickness distribution of the color filter layer 400. This makes the surface of the color filter layer 400 naturally flat after filling, reducing the use of additional flattening layers. This effectively improves the problems of increased thickness, decreased bending performance, and reduced light extraction efficiency caused by RGB stacking replacing BM in the COE structure of related technologies. It has significant technological progress and industrial application value.

[0117] In the description of this specification, references to terms such as "some embodiments," "exemplarily," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of this application. The illustrative expressions of the above terms in this specification do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in a suitable manner in any one or more embodiments or examples. Moreover, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0118] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application. Therefore, any changes or modifications made in accordance with the claims and description of this application should fall within the scope of this patent application.

Claims

1. A method for manufacturing a display panel, characterized by, Includes the following steps: A substrate is provided, on which multiple light-emitting device layers are disposed; A first inorganic encapsulation layer and an organic encapsulation layer are sequentially formed on the plurality of light-emitting device layers; A transfer substrate is provided, the transfer substrate including a first protrusion and a second protrusion, the first protrusion and the second protrusion being connected to each other, and the height of the first protrusion being greater than the height of the second protrusion; The transfer substrate with the first protrusion and the second protrusion is pressed against the organic encapsulation layer, so that the organic encapsulation layer forms a recessed pattern on the side away from the substrate that is complementary to the first protrusion and the second protrusion. The first protrusion forms a first recess at a corresponding position, the second protrusion forms a second recess at a corresponding position, and the depth of the first recess is greater than the depth of the second recess. Remove the transfer substrate; A second inorganic encapsulation layer and a color filter layer are sequentially formed on the organic encapsulation layer. The color filter layer fills the recessed pattern, and the surface of the color filter layer facing away from the substrate is a flat surface. The color filter layer includes color resist blocks of multiple colors, and the area between the first recess and the light-emitting device layer is correspondingly arranged. The first recess is filled with a stacked structure of color resist blocks of at least two different colors. The second recess is correspondingly arranged with the light-emitting device layer, and the second recess is filled with a color resist block of a single color.

2. The production method according to claim 1, characterized by, After pressing the side of the transfer substrate with the first protrusion and the second protrusion onto the organic encapsulation layer, the organic encapsulation layer is cured.

3. The production method according to claim 2, characterized by, The fabrication of the transfer substrate includes: Provide a transparent substrate; A patterned color resist layer is formed on the transparent substrate. The patterned color resist layer has a first protrusion and a second protrusion that are connected to each other. The height of the first protrusion is greater than the height of the second protrusion. The first protrusion corresponds to the region between the light-emitting device layers, and the second protrusion corresponds to the light-emitting device layer. An inorganic layer is formed on the patterned color resist layer; A sacrificial layer is formed on the inorganic layer.

4. The production method according to claim 3, characterized by, The step of removing the transfer substrate includes: A laser is irradiated from one side of the transparent substrate to decompose the sacrificial layer, thereby separating the transfer substrate from the organic encapsulation layer.

5. The preparation method according to claim 1, characterized in that, The fabrication of the transfer substrate includes: Provide a transparent substrate; A rigid layer is formed on the transparent substrate. The rigid layer includes a first protrusion and a second protrusion that are connected to each other, and the height of the first protrusion is greater than the height of the second protrusion. An inorganic layer is formed on the rigid layer.

6. The preparation method according to claim 5, characterized in that, Before pressing the side of the transfer substrate with the first protrusion and the second protrusion onto the organic encapsulation layer, the organic encapsulation layer is partially cured.

7. The preparation method according to claim 5, characterized in that, The formation of the first and second protrusions that are interconnected in the rigid layer includes: A rigid material layer is formed on the transparent substrate; A patterned color resist layer is formed on the rigid material layer. The patterned color resist layer has a first initial protrusion and a second initial protrusion that are connected to each other. The height of the first initial protrusion is greater than the height of the second initial protrusion. The first initial protrusion corresponds to the region between the light-emitting device layers, and the second initial protrusion corresponds to the light-emitting device layer. The patterned color resist layer and the rigid material layer are etched using a dry etching process. By utilizing the etching rate difference in different thickness regions of the patterned color resist layer, the uneven morphology of the patterned color resist layer is copied to the rigid material layer, so that the rigid material layer forms a first protrusion and a second protrusion that are interconnected, and the height of the first protrusion is greater than the height of the second protrusion.

8. The preparation method according to claim 6, characterized in that, After pressing the side of the transfer substrate with the first protrusion and the second protrusion onto the organic encapsulation layer, the organic encapsulation layer is completely cured.

9. A display panel, characterized in that, include: A substrate, on which multiple light-emitting device layers are disposed; A first inorganic encapsulation layer is disposed on the plurality of light-emitting device layers; An organic encapsulation layer is disposed on the first inorganic encapsulation layer. The organic encapsulation layer has a recessed pattern on the side opposite to the substrate. The recessed pattern includes a first recess and a second recess, and the depth of the first recess is greater than the depth of the second recess. A second inorganic encapsulation layer is disposed on the organic encapsulation layer; A color filter layer is disposed on the second inorganic encapsulation layer, the color filter layer fills the recessed pattern, and the surface of the color filter layer facing away from the substrate is a flat surface; The color filter layer includes color resist blocks of multiple colors, and the area between the first recess and the light-emitting device layer is correspondingly arranged. The first recess is filled with a stacked structure of color resist blocks of at least two different colors. The second recess is correspondingly arranged with the light-emitting device layer, and the second recess is filled with a color resist block of a single color.

10. The display panel according to claim 9, characterized in that, The color resist stack structure of at least two different colors includes at least two of red, green and blue color resist blocks.

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