Display panel and preparation method thereof

Abstract

The invention provides a display panel and a preparation method thereof, belongs to the technical field of display, and aims at reducing the bonding process and improving the product yield of the display panel. The display panel comprises a driving backboard and a light-emitting substrate located on one side of the driving backboard; the first contact pad is positioned on one side, close to the light-emitting substrate, of the driving back plate; the second contact pad is positioned on one side, close to the driving back plate, of the light-emitting substrate; and the bonding glue layer is located between the first contact pad and the second contact pad, and conductive nanoparticles are dispersed in the bonding glue layer.

Description

Technical Field

[0001] This disclosure relates to the field of display technology, and in particular to a display panel and a method for manufacturing the same. Background Technology

[0002] Compared to traditional display technologies, Micro-LED displays offer superior brightness, high luminous efficiency, low energy consumption, high response speed, high contrast, ultra-high resolution, and color saturation. Micro-LEDs typically employ metal bonding when bonding the light-emitting substrate to the driving backplane.

[0003] However, the metal bonding process has high requirements for process conditions and is difficult to thin, which results in a low yield of the resulting display panels. Summary of the Invention

[0004] Based on the background art, this disclosure proposes a display panel and a method for manufacturing the same.

[0005] In a first aspect, this disclosure provides a display panel, comprising: a driving backplate and a light-emitting substrate located on one side of the driving backplate;

[0006] The first contact pad is located on the side of the driving backplate close to the light-emitting substrate;

[0007] The second contact pad is located on the side of the light-emitting substrate closer to the driving back plate;

[0008] A bonding adhesive layer is located between the first contact pad and the second contact pad, and conductive nanoparticles are dispersed within the bonding adhesive layer.

[0009] Optionally, the material of the first contact pad and / or the material of the second contact pad includes a reflective metal.

[0010] Optionally, in the direction of the driving backplate toward the light-emitting substrate, the first contact pad and / or the second contact pad sequentially include a first conductive layer, a reflective layer, and a second conductive layer;

[0011] The first conductive layer and the second conductive layer comprise light-transmitting conductive materials, and the reflective layer comprises the reflective metal.

[0012] Optionally, the thickness of the bonding adhesive layer is 0.1 μm-2 μm.

[0013] Optionally, the conductive nanoparticles account for 1%-70% of the volume of the bonding adhesive layer, and the size of the conductive nanoparticles is 10-1000 nm.

[0014] Optionally, the conductive nanoparticles include at least one of indium tin oxide nanoparticles, indium zinc oxide nanoparticles, silver nanoparticles, tin nanoparticles, and gold nanoparticles; or, the conductive nanoparticles are core-shell structured nanoparticles, and the shell material of the core-shell structured nanoparticles is a conductive material.

[0015] Optionally, the display panel includes a plurality of light-emitting devices, each of which is connected to the driving backplate via the bonding adhesive layer;

[0016] The light-emitting substrate further includes:

[0017] A common electrode layer is located on the side of the light-emitting device away from the bonding adhesive layer, and the orthogonal projection of the common electrode layer on the driving backplate covers the entire surface of the multiple light-emitting devices.

[0018] An auxiliary electrode is located on the side of the common electrode layer opposite to the bonding adhesive layer. The orthographic projection of the auxiliary electrode on the driving backplate does not overlap with the orthographic projection of the light-emitting device on the driving backplate.

[0019] A second aspect of this disclosure provides a method for manufacturing a display panel, applied to the manufacturing of a display panel as described in the first aspect, the method comprising:

[0020] A driving backplate and a light-emitting substrate are provided. A first contact pad is provided on one side of the driving backplate, and a second contact pad is provided on one side of the light-emitting substrate.

[0021] On the side of the first contact pad facing away from the driving backplate, and / or on the side of the second contact pad facing away from the light-emitting substrate, a bonding adhesive is spin-coated to form a bonding adhesive layer, thereby obtaining the display panel; wherein conductive nanoparticles are dispersed within the bonding adhesive.

[0022] Optionally, after forming the bonding adhesive layer, the method further includes:

[0023] The light-emitting functional layer on the light-emitting substrate is etched to obtain multiple light-emitting devices;

[0024] In the same etching process, the first contact pad, the bonding adhesive layer, and the second contact pad are etched to obtain multiple contact units corresponding to the multiple light-emitting devices. Each contact unit includes the first contact pad, the bonding adhesive layer, and the second contact pad, wherein there is a gap between two adjacent contact units.

[0025] Optionally, the method further includes:

[0026] A common electrode layer is formed on the side of the plurality of light-emitting devices opposite to the bonding adhesive layer;

[0027] An auxiliary electrode is formed on the side of the common electrode layer away from the bonding adhesive layer. The orthographic projection of the auxiliary electrode on the driving backplate does not overlap with the orthographic projection of the light-emitting device on the driving backplate.

[0028] The display panel disclosed herein includes: a driving backplate and a light-emitting substrate located on one side of the driving backplate; a first contact pad located on the side of the driving backplate close to the light-emitting substrate; a second contact pad located on the side of the light-emitting substrate close to the driving backplate; and a bonding adhesive layer located between the first contact pad and the second contact pad, wherein conductive nanoparticles are dispersed in the bonding adhesive layer.

[0029] Therefore, this disclosure connects the first contact pad of the driving backplane and the second contact pad of the light-emitting substrate by using a bonding adhesive layer. Since the bonding adhesive layer can be formed by spin-coating the bonding adhesive and annealing, the bonding process conditions of the display panel are reduced, and the stress mismatch problem introduced by the high process conditions in metal bonding is avoided, which leads to a decrease in product yield. At the same time, since conductive nanoparticles are dispersed in the bonding adhesive layer, the electrical connection between the first contact pad and the second contact pad can be realized based on the conductive nanoparticles in the bonding adhesive layer, thereby realizing the electrical connection between the driving backplane and the light-emitting substrate.

[0030] The above description is merely an overview of the technical solution disclosed herein. In order to better understand the technical means of this disclosure and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this disclosure more apparent and understandable, specific embodiments of this disclosure are described below. Attached Figure Description

[0031] To more clearly illustrate the technical solutions in the embodiments or related technologies of this disclosure, the accompanying drawings used in the description of the embodiments or related technologies will be briefly introduced below. Obviously, the accompanying drawings described below are some embodiments of this disclosure. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort. It should be noted that the scale in the drawings is for illustration only and does not represent the actual scale.

[0032] Figure 1 A schematic diagram of the structure of a display panel provided in an embodiment of this disclosure is shown;

[0033] Figure 2 A schematic diagram of the structure of the first contact pad and the second contact pad in an embodiment of this disclosure is shown;

[0034] Figure 3 A schematic diagram of the structure of a display panel provided in yet another embodiment of this disclosure is shown;

[0035] Figure 4A schematic diagram of the structure of a display panel provided in another embodiment of this disclosure is shown;

[0036] Figure 5 A flowchart illustrating the steps of a method for manufacturing a display panel according to an embodiment of this disclosure is shown;

[0037] Figure 6a A schematic diagram of the structure of the light-emitting substrate in an embodiment of this disclosure is shown;

[0038] Figure 6b This diagram illustrates an intermediate structure obtained after forming the bonding adhesive layer in an embodiment of the present disclosure.

[0039] Figure 6c This diagram shows an intermediate structure obtained after etching the light-emitting functional layer on the light-emitting substrate in an embodiment of this disclosure.

[0040] Figure 6d This diagram illustrates an intermediate structure formed after etching the first contact pad, the bonding adhesive layer, and the second contact pad in an embodiment of the present disclosure.

[0041] Figure 6e This diagram illustrates an intermediate structure obtained after forming a common electrode layer on the side of the multiple light-emitting devices away from the bonding adhesive layer, according to an embodiment of this disclosure.

[0042] Explanation of reference numerals in the attached figures:

[0043] 10. Driving backplate; 20. Light-emitting substrate; 21. First electrode layer; 22. Light-emitting layer; 23. Second electrode layer; 24. Buffer layer; 25. Common electrode layer; 26. Auxiliary electrode; 30. First contact pad; 31. First conductive layer; 32. Reflective layer; 33. Second conductive layer; 40. Second contact pad; 50. Bonding adhesive layer; 51. Conductive nanoparticles; 200. Light-emitting device. Detailed Implementation

[0044] To make the above-mentioned objectives, features, and advantages of this disclosure more apparent and understandable, the technical solutions of the embodiments of this disclosure will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this disclosure. Based on the embodiments of this disclosure, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this disclosure.

[0045] Micro LED is considered an ideal display technology due to its excellent brightness, high luminous efficiency, low energy consumption, high response speed, high contrast, ultra-high resolution and color saturation. However, the development of micro LED is constrained by problems such as the difficulty in achieving uniform epitaxial layers, high requirements for miniaturization processes, and harsh bonding technology conditions.

[0046] Metal bonding is typically used to bond micro LEDs to the backplane. However, the metal bonding process requires high pressure and temperature and suffers from stress mismatch after bonding, which reduces product yield.

[0047] In view of this, this disclosure proposes a display panel and its manufacturing method, which uses a bonding adhesive layer to bond the first contact pad and the second contact pad, and achieves electrical connection between the driving backplane and the light-emitting substrate through conductive nanoparticles dispersed in the bonding adhesive layer. Since the bonding process conditions using bonding adhesive are lower than those of metal bonding, the bonding process is simplified. At the same time, due to the low bonding process conditions when using bonding adhesive, the bonding process between the driving backplane and the light-emitting substrate is less affected by stress, avoiding warping or bending of micro LEDs due to external forces or stress caused by bonding, thereby improving product yield.

[0048] Reference Figure 1 , Figure 1 A schematic diagram of the structure of a display panel provided in an embodiment of this disclosure is shown, such as... Figure 1 As shown, the display panel specifically includes: a driving backplate 10 and a light-emitting substrate 20 located on one side of the driving backplate 10;

[0049] The first contact pad 30 is located on the side of the driving backplate 10 near the light-emitting substrate 20;

[0050] The second contact pad 40 is located on the side of the light-emitting substrate 20 near the driving back plate 10;

[0051] The bonding adhesive layer 50 is located between the first contact pad 30 and the second contact pad 40, and conductive nanoparticles 51 are dispersed within the bonding adhesive layer 50.

[0052] In this example, the driving backplane 10 can be made of silicon as a substrate using complementary metal-oxide-semiconductor technology. That is, the driving backplane 10 includes multiple CMOS circuits, and the surface of the driving backplane 10 is provided with multiple first contact pads 30 that are respectively connected to each CMOS circuit. The multiple light-emitting devices 200 included in the light-emitting substrate 20 can be electrically connected to the multiple CMOS circuits through multiple conductive pads, thereby enabling the CMOS circuits to provide driving signals to the light-emitting substrate 20.

[0053] The light-emitting substrate 20 includes, in sequence, a first electrode layer 21, a light-emitting layer 22, a second electrode layer 23, and a buffer layer 24 in the direction from the first contact pad 30 to the second contact pad 40. The first contact pad 30 is located on the side of the first electrode layer 21 opposite to the light-emitting layer 22. The first electrode layer 21 comprises a p-type semiconductor material, such as p-type gallium nitride; the second electrode layer 23 comprises an n-type semiconductor material, such as n-type gallium nitride; and the light-emitting layer 22 is a multi-quantum-well layer.

[0054] The first contact pad 30 is a p-type ohmic contact pad, which can be a transparent conductive material such as indium tin oxide (ITO). The second contact pad 40 can also be a transparent conductive material such as ITO.

[0055] The bonding adhesive layer 50 can be formed by spin-coating bonding adhesive onto the surface of the first contact pad 30 or the second contact pad 40. The bonding adhesive can be a permanent bonding adhesive such as epoxy resin, so as to firmly bond the driving backplate 10 and the light-emitting substrate 20. Spin coating is used to prepare the bonding layer, which has lower bonding requirements and can usually be achieved at room temperature or a lower temperature. Therefore, during the fabrication of the display panel, the stress mismatch caused by the different thermal expansion coefficients of the layers on the light-emitting substrate 20 and the driving backplate 10 during the heating and cooling process can be avoided. This also avoids the problem of warping and bending of the epitaxial layer during the bonding process, which would reduce the product yield. In addition, the thickness of the bonding adhesive layer 50 formed by spin coating is easier to control. A thinner bonding adhesive layer 50 can be obtained during the bonding process, which facilitates the patterning of the bonding adhesive layer 50. In contrast, the metal bonding layer obtained by the metal bonding method used in related technologies is difficult to bond after thinning and is prone to stress problems. Therefore, using the bonding adhesive layer 50 can reduce the thickness of the bonding layer between the driving backplate 10 and the light-emitting substrate 20, and reduce the overall thickness of the display panel.

[0056] The bonding adhesive forming the bonding layer 50 typically lacks conductivity. Using only the bonding adhesive layer 50 to bond the driving backplate 10 and the light-emitting substrate 20 is insufficient to achieve electrical connection between them. Therefore, conductive nanoparticles 51 can be mixed into the bonding adhesive layer 50 to achieve electrical connection between the driving backplate 10 and the light-emitting substrate 20. The mixing ratio of the conductive nanoparticles in the bonding adhesive layer 50 should be sufficient to achieve electrical connection between the light-emitting substrate 20 and the driving backplate 10. It is understood that the conductive nanoparticles 51 are uniformly dispersed in the bonding adhesive layer 50, thus giving the bonding adhesive layer 50 good conductivity. The conductive nanoparticles can be non-metallic nanoparticles with conductivity, or metallic nanoparticles. Alternatively, the conductive nanoparticles can be core-shell structured nanoparticles, where the shell material is conductive and the core material can be conductive or non-conductive.

[0057] It should be noted that although ITO can also achieve bonding, it requires high bonding conditions. The surface roughness Ra (Roughness Average) of the surfaces to be bonded is less than 0.5 mm, and the bonding process is carried out in a high temperature and high pressure environment. In contrast, the bonding adhesive layer obtained by the bonding adhesive mixed with conductive nanoparticles in this embodiment can achieve bonding at room temperature or low temperature.

[0058] In one example, the first contact pad 30 and / or the second contact pad 40 may include a reflective material, so that when a portion of the light emitted from the light-emitting substrate 20 is directed toward the driving backplate 10, the light can be reflected back to the light-emitting substrate 20 by the first contact pad 30 and / or the second contact pad 40, allowing the light that was originally trapped inside the display panel to be emitted, thereby improving the luminous efficiency.

[0059] It is understandable that, since the bonding adhesive layer 50 is located between the first contact pad 30 and the second contact pad 40, and if the first contact pad 30 and / or the second contact pad 40 include a reflective material, the conductive nanoparticles 51 can be a reflective material or a transparent material. This allows reflection to be achieved through the first contact pad 30, the second contact pad 40, and the conductive nanoparticles 51 in the bonding adhesive layer 50, thereby improving the luminous efficiency of the display panel. For example, the conductive nanoparticles 51 can be transparent materials such as indium tin oxide nanoparticles or indium zinc oxide nanoparticles, or reflective materials such as silver nanoparticles or aluminum nanoparticles.

[0060] The display panel provided in this embodiment includes a driving backplate 10 and a light-emitting substrate 20. A first contact pad 30 is disposed on the side of the driving backplate 10 near the light-emitting substrate 20, and a second contact pad 40 is disposed on the side of the light-emitting substrate 20 near the driving backplate 10. The first contact pad 30 and the second contact pad 40 are connected by a bonding adhesive layer 50, and conductive nanoparticles 51 are dispersed in the bonding adhesive layer 50. Thus, the connection between the driving backplate 10 and the light-emitting substrate 20 is achieved through the bonding adhesive. Because the conductive nanoparticles 51 are dispersed within the bonding adhesive layer 50, the conductive nanoparticles 51 can... Electrical connection is achieved between the first contact pad 30 and the second contact pad 40. In this way, bonding between the driving backplate 10 and the light-emitting substrate 20 can be achieved by bonding adhesive. The bonding process conditions for bonding adhesive are lower than those required for metal bonding, making the bonding process simpler and easier. It also avoids the problem of reduced product yield caused by stress mismatch between the light-emitting substrate 10 and the growth substrate in metal bonding. Furthermore, the thickness of the bonding adhesive layer 50 is easy to control during the bonding process, allowing the bonding adhesive layer 50 to be thinner than the bonding layer formed by metal bonding, which facilitates the subsequent patterning process.

[0061] In one embodiment, the material of the first contact pad 30 and / or the material of the second contact pad 40 includes a reflective metal.

[0062] Specifically, the material of the first contact pad 30 may include reflective metal, the material of the second contact pad 40 may include reflective metal, or both the first contact pad 30 and the second contact pad 40 may include reflective metal.

[0063] In the case where the material of the first contact pad 30 includes a reflective metal, the light emitted from the light-emitting layer 22 to the driving backplate 10 is reflected within the first contact pad 30 and emitted in the direction of the light-emitting layer 22. This avoids the problem of light emitted to the driving backplate 10 remaining inside the device and reducing the luminous efficiency.

[0064] When the material of the second contact pad 40 includes a reflective metal, the first contact pad 30 is a transparent conductive material, and the conductive nanoparticles 51 in the bonding adhesive layer 50 can be a transparent material or a reflective material. If the conductive nanoparticles 51 are transparent, the light emitted toward the driving backplate 10 passes through the first contact pad 30 and the bonding adhesive layer 50 and enters the second contact pad 40, where it is reflected by the second contact pad 40 and emitted toward the light-emitting substrate 10. For example, the conductive nanoparticles 51 are ITO nanoparticles. Since ITO is a transparent material, the light emitted toward the driving backplate 10 can pass through the bonding adhesive layer 50 where the conductive nanoparticles 51 are located and be reflected by the second contact pad 40. In this way, the light originally emitted toward the side where the driving backplate 10 is located can be reflected toward the direction where the light-emitting substrate 20 is located, thereby improving the luminous efficiency of the display panel.

[0065] If the conductive nanoparticles 51 are reflective materials, the bonding adhesive layer 50 and the second contact pad 40 can jointly reflect the light emitted from the light-emitting layer 22 toward the driving backplate 10. When both the materials of the first contact pad 30 and the second contact pad 40 include reflective metals, both the first contact pad 30 and the second contact pad 40 can reflect light incident from the side where the light-emitting substrate 20 is located. For example, if the conductive nanoparticles are silver nanoparticles, since the silver nanoparticles are reflective materials, the light emitted toward the driving backplate 10 can be reflected by the bonding adhesive layer 50 to be emitted toward the direction where the light-emitting substrate 20 is located, thus improving the luminous efficiency of the display panel.

[0066] In one embodiment, the first contact pad 30 and the second contact pad 40 are composite materials obtained by mixing conductive materials and reflective metals. To achieve a better reflective effect, refer to... Figure 2 , Figure 2 A schematic diagram of the structure of the first contact pad 30 and the second contact pad 40 in an embodiment of this disclosure is shown, as follows: Figure 2As shown, in the direction of the driving backplate 10 toward the light-emitting substrate 20, the first contact pad 30 and / or the second contact pad 40 sequentially include a first conductive layer 31, a reflective layer 32 and a second conductive layer 33; wherein, the first conductive layer 31 and the second conductive layer 33 include light-transmitting conductive materials, and the reflective layer 32 is made of metal.

[0067] In this embodiment, the reflective layer 32 includes reflective metals such as silver and aluminum. Since the reflective metal has poor adhesion to other layers, a first conductive layer 31 and a second conductive layer 32 are disposed on opposite sides of the reflective layer 32 to achieve bonding between the reflective layer and other layers. Both the first conductive layer 31 and the second conductive layer 32 are transparent and conductive materials, allowing light incident on the first contact pad 30 or the second contact pad 40 to be reflected on the surface of the reflective layer 32. Specifically, when the first contact pad 30 includes a first conductive layer 31, a reflective layer 32, and a second conductive layer 33, the first conductive layer 31 is located on the side of the bonding adhesive layer 50 away from the driving backplate 10, and the second conductive layer 32 is located on the side of the light-emitting substrate 20 close to the driving backplate 10. Similarly, when the second contact pad 40 includes a first conductive layer 31, a reflective layer 32, and a second conductive layer 33, the first conductive layer 31 is located on the side of the driving backplate 10 close to the light-emitting substrate 20, and the second conductive layer 33 is located on the side of the bonding adhesive layer 50 away from the first contact pad 30.

[0068] In one embodiment, the thickness of the bonding adhesive layer is 0.1 μm-2 μm.

[0069] For example, the thickness of the bonding adhesive layer can be 0.1 μm, 0.5 μm, 1 μm, 1.5 μm or 2 μm, etc.

[0070] In one embodiment, the conductive nanoparticles 51 account for 1%-70% of the volume of the bonding adhesive layer 50, and the size of the conductive nanoparticles 51 is 10-1000 nm.

[0071] For example, the volume percentage of conductive nanoparticles 51 in the bonding adhesive layer 50 is 1%, 5%, 10%, 30%, 50%, or 70%, etc.; the size of conductive nanoparticles 51 is 10nm, 50nm, 100nm, 500nm, or 1000nm, etc.

[0072] In this embodiment, the mixing ratio of conductive nanoparticles 51 in the bonding adhesive layer 50 can be adjusted according to the thickness of the bonding adhesive layer 50. When the bonding adhesive layer 50 is thinner, it is easier for the conductive nanoparticles 51 to contact the first contact pad 30 and the second contact pad 40, and the mixing ratio of conductive nanoparticles 51 in the bonding adhesive layer 50 can be lower. However, when the bonding adhesive layer 50 is thicker, it is difficult for the conductive nanoparticles 51 to contact the first contact pad 30 and the second contact pad 40, so a higher mixing ratio of conductive nanoparticles 51 in the bonding adhesive layer 50 is needed to achieve electrical connection between the first contact pad 30 and the second contact pad 40. Similarly, the size of the conductive nanoparticles 51 can also be determined according to the thickness of the bonding adhesive layer 50. When the bonding layer 50 is thinner, a smaller size of the conductive nanoparticles 51 can also achieve electrical connection between the first contact pad 30 and the second contact pad 40. When the bonding adhesive layer 50 is thicker, the size of the conductive nanoparticles 51 needs to be larger to avoid an excessively high mixing ratio of conductive nanoparticles 51 in the bonding adhesive layer 50, which could reduce the bonding strength.

[0073] In one embodiment, the conductive nanoparticles 51 include at least one of indium tin oxide nanoparticles, indium zinc oxide nanoparticles, silver nanoparticles, tin nanoparticles, and gold nanoparticles; or, the conductive nanoparticles are core-shell structured nanoparticles, and the shell material of the core-shell structured nanoparticles is a conductive material.

[0074] In the case where the conductive nanoparticle 51 is a core-shell structured nanoparticle, its conductivity can be achieved by its shell material being a conductive material, and its core can be a conductive material or a non-conductive material.

[0075] For example, the conductive nanoparticle 51 is an indium tin oxide nanoparticle, an indium zinc oxide nanoparticle, or a silver nanoparticle. The conductive nanoparticle 51 can also be a mixture of indium tin oxide nanoparticles and indium zinc oxide nanoparticles. The conductive nanoparticle 51 can also be a core-shell structured nanoparticle with gold nanoparticles as the core and silver as the shell material.

[0076] In this embodiment, when the material of the first contact pad 30 includes a reflective metal, most of the light emitted from the light-emitting substrate 20 toward the driving back plate 10 is reflected by the first contact pad 30. Thus, the conductive nanoparticles 51 can achieve electrical connection between the first contact pad 30 and the second contact pad 40. Therefore, the conductive nanoparticles 51 can be light-transmitting materials such as indium tin oxide nanoparticles and indium zinc oxide nanoparticles, or reflective materials such as silver nanoparticles, or light-absorbing materials such as tin nanoparticles and gold nanoparticles. When the material of the second contact pad 40 includes a reflective metal, the conductive nanoparticles 51 are either reflective or transparent. When the conductive nanoparticles 51 are reflective, the bonding adhesive layer 50 and the second contact pad 40 together reflect the light emitted from the light-emitting substrate 20 toward the driving backplate 10. When the conductive nanoparticles 51 are transparent, the bonding adhesive layer 50 allows the light emitted from the light-emitting substrate 20 toward the driving backplate 10 to pass through. The transmitted light is reflected by the second contact pad 40 and passed through the bonding adhesive layer 50, so that the reflected light can be emitted again from the side of the light-emitting substrate 20 away from the driving backplate 10, thereby improving the luminous efficiency of the display panel.

[0077] In one embodiment, reference is made to Figure 3 , Figure 3 A schematic diagram of the structure of a display panel provided in another embodiment of this disclosure is shown, as follows: Figure 3 As shown, the display panel includes multiple light-emitting devices, each of which is connected to the driving backplate 10 via a bonding adhesive layer 50;

[0078] The light-emitting substrate 20 also includes:

[0079] The common electrode layer 25 is located on the side of the light-emitting device away from the bonding adhesive layer 50. The orthogonal projection of the common electrode layer 25 on the driving backplate 10 covers the entire surface of multiple light-emitting devices.

[0080] The auxiliary electrode 26 is located on the side of the common electrode layer 25 away from the bonding adhesive layer 50. The orthographic projection of the auxiliary electrode 26 on the driving backplate 10 does not overlap with the orthographic projection of the light-emitting device on the driving backplate 10.

[0081] Specifically, in this embodiment, after etching the first electrode layer 21, the light-emitting layer 22 and the second electrode layer 23 in the light-emitting substrate 20, a plurality of light-emitting devices are formed. Each light-emitting device is connected to the driving backplate 10 through the bonding adhesive layer 50. A common electrode layer 25 is provided on the side of the light-emitting device away from the bonding adhesive layer. The orthogonal projection of the common electrode layer 25 on the driving backplate covers the entire surface of the plurality of light-emitting devices.

[0082] An auxiliary electrode 26 is provided on the side of the common electrode layer 25 away from the bonding adhesive layer 50. The auxiliary electrode 26 is used to enhance the current spreading effect of the common electrode layer 25 so that the current can be injected uniformly. The auxiliary electrode can be composed of a grid-like titanium-aluminum-titanium laminated metal structure.

[0083] The display panel provided in this embodiment uses a bonding adhesive layer 50 to bond a first contact pad 30 located on the side of the driving backplate 10 near the light-emitting substrate 20 to a second contact pad 40 located on the side of the light-emitting substrate 20 near the driving backplate 10. Since the bonding adhesive layer 50 is formed by spin-coating bonding adhesive, the bonding method is simple and easy to implement, and the bonding process does not cause stress problems, thus improving the product yield of the display panel. At the same time, conductive nanoparticles 51 are dispersed in the bonding adhesive layer 50, which enables the bonding adhesive layer 50 to be conductive, thereby making the driving backplate 10 and the light-emitting substrate 20 electrically connected. In addition, the conductive nanoparticles 51 in the bonding adhesive layer 50 are light-transmitting or reflective materials, and the materials of the first contact pad 30 and / or the second contact pad 40 include reflective metals. That is, the light emitted from the light-emitting substrate 20 toward the driving backplate 10 can be reflected by the first contact pad 30, the bonding adhesive layer 50, and the second contact pad 40, thereby improving the luminous efficiency of the display panel.

[0084] The display panel provided in the embodiments of this disclosure will now be described in detail using specific examples:

[0085] Example 1: Continue to refer to Figure 2 The display panel includes a driving backplate 10 and a light-emitting substrate 20 located on one side of the driving backplate 10. A first contact pad 30 is disposed on the side of the driving backplate 10 near the light-emitting substrate 20, and a second contact pad 40 is disposed on the side of the light-emitting substrate 20 near the driving backplate 10. A bonding adhesive layer 50 is disposed between the first contact pad 30 and the second contact pad 40, and conductive nanoparticles 51 are dispersed in the bonding adhesive layer 50. The light-emitting substrate 20 includes a first electrode layer 21, a light-emitting layer 22, and a second electrode layer 23. The first electrode layer 21 is p-type gallium nitride, the light-emitting layer 22 is a multiple quantum well, and the second electrode is n-type gallium nitride.

[0086] The first contact pad 30 comprises ITO, and the second contact pad 40 comprises a first conductive layer 31, a reflective layer 32, and a second conductive layer 33. The first conductive layer 31 and the second conductive layer 33 comprise ITO, and the reflective layer is Ag. The thickness of the bonding adhesive layer 50 can be 0.1 μm, 0.5 μm, 1 μm, or 2 μm, etc. The conductive nanoparticles in the bonding adhesive layer 50 can be indium tin oxide nanoparticles, indium zinc oxide nanoparticles, silver nanoparticles, etc. The size of the conductive nanoparticles 51 can be 10 nm, 100 nm, 500 nm, or 1000 nm, etc. The volume percentage of the conductive nanoparticles 51 in the bonding adhesive layer 50 can be 1%, 10%, 30%, or 70%, etc. For example, the thickness of the bonding adhesive layer 50 is 0.5 μm, and the conductive nanoparticles 51 in the bonding adhesive layer 50 are indium tin oxide nanoparticles or silver nanoparticles with a size of 300 nm. The volume ratio of the conductive nanoparticles 51 in the bonding adhesive layer 50 is 20%. When the thickness of the bonding adhesive layer 50 is small and the volume ratio of the conductive nanoparticles 51 is small, the electrical connection between the driving backplate 10 and the light-emitting substrate 20 can be achieved.

[0087] The display panel shown in Example 1 uses a bonding adhesive layer 50 to bond the first contact pad 30 and the second contact pad 40, thereby electrically connecting the driving backplate 10 and the light-emitting substrate 20. Since the bonding adhesive layer 50 is formed by spin coating, the bonding method is simple and easy to implement. Compared with the metal bonding method in related technologies, the thickness of the bonding layer is smaller, which is beneficial to reducing the overall thickness of the display panel. In addition, since the second contact pad 40 includes a reflective layer 32, the reflective layer 32 can reflect the light emitted from the light-emitting substrate 20 toward the driving backplate 10 to the direction where the light-emitting substrate 20 is located, so that the light that was originally trapped in the device can be emitted, thereby improving the luminous efficiency of the display panel.

[0088] Example 2: Reference Figure 4 , Figure 4 A schematic diagram of the structure of a display panel provided in another embodiment of this disclosure is shown, such as... Figure 4 As shown, the display panel includes: a driving backplate 10 and a light-emitting substrate 20 located on one side of the driving backplate 10; a first contact pad 30 is disposed on the side of the driving backplate 10 near the light-emitting substrate 20, and a second contact pad 40 is disposed on the side of the light-emitting substrate 20 near the driving backplate 10; a bonding adhesive layer 50 is disposed between the first contact pad 30 and the second contact pad 40, and conductive nanoparticles 51 are dispersed within the bonding adhesive layer 50. The light-emitting substrate 20 includes a first electrode layer 21, a light-emitting layer 22, a second electrode layer 23, and a buffer layer 24. The first electrode layer 21 is p-type gallium nitride, the light-emitting layer 22 is a multiple quantum well, the second electrode layer 23 is n-type gallium nitride, and the buffer layer 24 is a gallium nitride layer.

[0089] The second contact pad 40 comprises ITO, a first conductive layer 31, a reflective layer 32, and a second conductive layer 33. The first and second conductive layers 31 and 33 are ITO, and the reflective layer is Ag. The thickness of the bonding adhesive layer 50 can be 0.1 μm, 0.5 μm, 1 μm, or 2 μm, etc. The conductive nanoparticles within the bonding adhesive layer 50 can be tin nanoparticles, gold nanoparticles, or core-shell structured nanoparticles, etc. The size of the conductive nanoparticles 51 can be 10 nm, 100 nm, 500 nm, or 1000 nm, etc. The volume percentage of the conductive nanoparticles 51 within the bonding adhesive layer 50 can be 1%, 10%, 30%, or 70%, etc. For example, the thickness of the bonding adhesive layer 50 is 0.3 μm, the conductive nanoparticles 51 within the bonding adhesive layer 50 are tin nanoparticles with a size of 100 nm, and the volume percentage of the conductive nanoparticles 51 within the bonding adhesive layer 50 is 30%, etc. Since the light emitted toward the driving backplate 10 is reflected by the second contact pad 40, the conductive nanoparticles 51 only need to have conductive properties. When the thickness of the bonding adhesive layer 50 is small, if the size of the conductive nanoparticles 51 is small, the volume ratio of the conductive nanoparticles 51 in the bonding adhesive layer 50 can be appropriately increased to ensure the electrical connection between the driving backplate 10 and the light-emitting substrate 20.

[0090] The display panel shown in Example 2 uses a bonding adhesive layer 50 to bond the first contact pad 30 and the second contact pad 40, thereby electrically connecting the driving backplate 10 and the light-emitting substrate 20. Since the bonding adhesive layer 50 is formed by spin coating, the bonding method is simple and easy to implement. Compared with the metal bonding method in related technologies, the thickness of the bonding layer is smaller, which is beneficial to reducing the overall thickness of the display panel. In addition, since the first contact pad 30 includes a reflective layer 32 and the conductive nanoparticles 51 in the bonding adhesive layer 50 are reflective, the light emitted from the light-emitting substrate 20 toward the driving backplate 10 can be reflected by the bonding adhesive layer 50 and the first contact pad 30 to the direction where the light-emitting substrate 20 is located, so that the light that was originally trapped in the device can be emitted, thereby improving the luminous efficiency of the display panel.

[0091] Based on the same inventive concept, this disclosure also provides a method for manufacturing a display panel, used to manufacture a display panel as described in the above embodiments. Specifically, refer to... Figure 5 , Figure 5 A flowchart illustrating the steps of a method for manufacturing a display panel according to an embodiment of this disclosure is shown, as follows: Figure 5 As shown, the preparation method specifically includes:

[0092] S101 provides a driving backplate and a light-emitting substrate. A first contact pad is provided on one side of the driving backplate, and a second contact pad is provided on one side of the light-emitting substrate.

[0093] S102, on the side of the first contact pad away from the driving backplate and / or the side of the second contact pad away from the light-emitting substrate, a bonding adhesive is spin-coated to form a bonding adhesive layer to obtain a display panel; wherein conductive nanoparticles are dispersed in the bonding adhesive layer.

[0094] Among them, reference Figure 6a and Figure 6b , Figure 6a A schematic diagram of the light-emitting substrate is shown. Figure 6b A schematic diagram of the intermediate structure after the bonding adhesive layer is formed is shown, as follows. Figure 6a and Figure 6b As shown, the light-emitting substrate 20 includes a first electrode layer 21, a light-emitting layer 22, and a second electrode layer 23 located on the growth substrate. A second contact pad 40 is disposed on the side of the first electrode layer 21 facing away from the growth substrate, and a first contact pad 30 is disposed on the side of the driving backplate 10. When forming the bonding adhesive layer 50, the bonding adhesive can be spin-coated on the side of the first contact pad 30 facing away from the driving backplate 10, or it can be spin-coated on the side of the second contact pad 40 facing away from the light-emitting substrate 20, or it can be spin-coated on both the side of the first contact pad 30 facing away from the driving backplate 10 and the side of the second contact pad 40 facing away from the light-emitting substrate 20, as long as the first contact pad 30 and the second contact pad 40 are bonded together. Conductive nanoparticles 51 are dispersed in the bonding adhesive layer 50. The mixing ratio of the conductive nanoparticles 51 in the bonding adhesive layer 50 is 1%-70%, and the size of the conductive nanoparticles 51 is 10-1000 nm. The conductive nanoparticles 51 include indium tin oxide nanoparticles, indium zinc oxide nanoparticles, and silver nanoparticles, etc.

[0095] In this embodiment, the first electrode layer 21, the light-emitting layer 22, and the second electrode layer 23 are all formed on the growth substrate. After the first contact pad 30 and the second contact pad 40 are bonded, the growth substrate can be peeled off. The method for peeling off the growth substrate can be selected according to the material of the growth substrate. For example, when the growth substrate is made of sapphire or silicon carbide, laser lift-off (LLO) technology can be used to peel off the growth substrate. After peeling off the growth substrate, the gallium particles attached to the light-emitting substrate are cleaned with acid. When the growth substrate is made of silicon, the silicon growth substrate is first mechanically thinned to below 200 μm, and then peeled off using a silicon stripping solution or a dry etching method.

[0096] The bonding method for the display panel provided in this disclosure uses bonding adhesive to bond the first contact pad and the second contact pad. Compared with metal bonding, the process conditions for bonding with bonding adhesive are lower, making the preparation process simpler and easier. Moreover, the bonding process is less likely to cause thermal runaway problems, thus improving the product yield of the display panel. Furthermore, the bonding layer thickness can be reduced compared with metal bonding, and the bonding adhesive layer is easier to pattern. In addition, since conductive nanoparticles are dispersed in the formed bonding adhesive layer, the bonding adhesive layer can conduct electricity, thereby realizing the electrical connection between the driving backplane and the light-emitting substrate.

[0097] Understandably, after forming the bonding adhesive layer, etching is required to obtain multiple light-emitting devices. Specifically, this includes: first, etching the light-emitting functional layer on the light-emitting substrate to obtain multiple light-emitting devices; then, in the same etching process, etching the first contact pad, the bonding adhesive layer, and the second contact pad to obtain multiple contact units corresponding to the multiple light-emitting devices. Each contact unit includes a first contact pad, a bonding adhesive layer, and a second contact pad, wherein there is a gap between two adjacent contact units.

[0098] Specifically, after peeling off the growth substrate, the light-emitting functional layer on the light-emitting substrate needs to be etched to form multiple light-emitting devices, as shown in the figure. Figures 6c-6d , Figure 6c A schematic diagram of the intermediate structure obtained after etching the light-emitting functional layer on the light-emitting substrate is shown. Figure 6d This diagram illustrates the intermediate structure formed after etching the first contact pad, the bonding adhesive layer, and the second contact pad. Figure 6c and Figure 6d As shown, the first electrode layer 21, the light-emitting layer 22, and the second electrode layer 23 are etched using a dry etching method to obtain multiple light-emitting devices. Then, the first contact pad 30, the bonding adhesive layer 50, and the second contact pad 40 are etched to obtain multiple contact units corresponding to the multiple light-emitting devices. Each contact unit includes the first contact pad 30, the bonding adhesive layer 50, and the second contact pad 40. At this time, the multiple light-emitting devices are arranged at intervals, and each light-emitting device is electrically connected to the driving backplane 10 through a contact unit.

[0099] It is understandable that the display panel also includes a common electrode connected to multiple light-emitting devices. After etching to obtain multiple light-emitting devices, the fabrication method of the display panel also includes: first, forming a common electrode layer on the side of the multiple light-emitting devices away from the bonding adhesive layer; then, forming an auxiliary electrode on the side of the common electrode layer away from the bonding adhesive layer, wherein the orthographic projection of the auxiliary electrode on the driving backplate does not overlap with the orthographic projection of the light-emitting devices on the driving backplate.

[0100] Specifically, refer to Figure 6e , Figure 6eThis diagram illustrates an intermediate structure obtained after forming a common electrode layer on the side of multiple light-emitting devices away from the bonding adhesive layer. Figure 6e As shown, after forming multiple light-emitting devices, an insulating layer is first covered on the side of the multiple light-emitting devices away from the driving backplate 10. This insulating layer can be SiO2, SiN, or SiON, or a sandwich of any two or three of SiO2, SiN, and SiON, or an organic insulating layer, such as SOG or BCB. Then, holes are made in the insulating layer to expose the second electrode layer 23. Next, a common electrode layer 25 is formed on the side of the insulating layer away from the light-emitting devices. This common electrode layer 25 is an ITO transparent electrode, electrically connected to the second electrode layer 23 of each light-emitting device, and allows light emitted by the light-emitting devices to pass through. Then, an auxiliary electrode 26 is formed on the side of the common electrode layer 25 away from the bonding adhesive layer. This auxiliary electrode 26 can be composed of a grid-like titanium-aluminum-titanium laminated metal structure. Its orthographic projection on the driving backplate 10 does not overlap with the orthographic projection of the light-emitting devices on the driving backplate 10. Thus, the auxiliary electrode 26 can be located in a non-light-emitting area, avoiding blocking the light emitted by the light-emitting devices. After forming the auxiliary electrode, a display panel is obtained, as shown... Figure 3 As shown.

[0101] In addition to fabricating the auxiliary electrode, a lens structure can be fabricated on the side of the auxiliary electrode away from the bonding adhesive layer. This lens structure can include organic or inorganic materials such as SiO2, SiON, or SiN, which can further improve the luminous efficiency of the display panel.

[0102] The various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.

[0103] Finally, it should be noted that in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0104] The above provides a detailed description of a display panel and its manufacturing method. Specific examples have been used to illustrate the principles and implementation methods of this disclosure. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this disclosure. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this disclosure. Therefore, the content of this specification should not be construed as a limitation of this disclosure.

[0105] Other embodiments of this disclosure will readily occur to those skilled in the art upon consideration of the specification and practice of the invention disclosed herein. This disclosure is intended to cover any variations, uses, or adaptations of this disclosure that follow the general principles of this disclosure and include common knowledge or customary techniques in the art not disclosed herein. The specification and examples are to be considered exemplary only, and the true scope and spirit of this disclosure are indicated by the following claims.

[0106] It should be understood that this disclosure is not limited to the precise structures described above and shown in the accompanying drawings, and various modifications and changes can be made without departing from its scope. The scope of this disclosure is limited only by the appended claims.

[0107] The terms "an embodiment," "embodiment," or "one or more embodiments" as used herein mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of this disclosure. Furthermore, please note that the examples of the phrase "in one embodiment" do not necessarily all refer to the same embodiment.

[0108] Numerous specific details are set forth in the specification provided herein. However, it will be understood that embodiments of this disclosure may be practiced without these specific details. In some instances, well-known methods, structures, and techniques have not been shown in detail so as not to obscure the understanding of this specification.

[0109] In the claims, any reference signs placed between parentheses should not be construed as limiting the claims. The word "comprising" does not exclude the presence of elements or steps not listed in the claims. The word "a" or "an" preceding an element does not exclude the presence of a plurality of such elements. This disclosure can be implemented by means of hardware comprising a plurality of different elements and by means of a suitably programmed computer. In a unit claim enumerating a plurality of means, several of these means may be embodied by the same item of hardware. The use of the words first, second, and third, etc., does not indicate any order. These words may be interpreted as names.

[0110] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this disclosure, and are not intended to limit them. Although this disclosure has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this disclosure.

Claims

1. A display panel, characterized in that, include: A driving backplate and a light-emitting substrate located on one side of the driving backplate; The first contact pad is located on the side of the driving backplate close to the light-emitting substrate; The second contact pad is located on the side of the light-emitting substrate closer to the driving back plate; A bonding adhesive layer is located between the first contact pad and the second contact pad, and conductive nanoparticles are dispersed within the bonding adhesive layer.

2. The display panel according to claim 1, characterized in that, The material of the first contact pad and / or the material of the second contact pad includes reflective metal.

3. The display panel according to claim 2, characterized in that, In the direction of the driving backplate toward the light-emitting substrate, the first contact pad and / or the second contact pad sequentially include a first conductive layer, a reflective layer and a second conductive layer; The first conductive layer and the second conductive layer comprise light-transmitting conductive materials, and the reflective layer comprises the reflective metal.

4. The display panel according to claim 1, characterized in that, The thickness of the bonding adhesive layer is 0.1μm-2μm.

5. The display panel according to claim 1, characterized in that, The conductive nanoparticles account for 1%-70% of the volume of the bonding adhesive layer, and the size of the conductive nanoparticles is 10-1000 nm.

6. The display panel according to claim 1, characterized in that, The conductive nanoparticles include at least one of indium tin oxide nanoparticles, indium zinc oxide nanoparticles, silver nanoparticles, tin nanoparticles, and gold nanoparticles, or the conductive nanoparticles are core-shell structured nanoparticles, and the shell material of the core-shell structured nanoparticles is a conductive material.

7. The display panel according to claim 1, characterized in that, The display panel includes a plurality of light-emitting devices, each of which is connected to the driving backplate via the bonding adhesive layer; The light-emitting substrate further includes: A common electrode layer is located on the side of the light-emitting device away from the bonding adhesive layer, and the orthogonal projection of the common electrode layer on the driving backplate covers the entire surface of the multiple light-emitting devices. An auxiliary electrode is located on the side of the common electrode layer opposite to the bonding adhesive layer. The orthographic projection of the auxiliary electrode on the driving backplate does not overlap with the orthographic projection of the light-emitting device on the driving backplate.

8. A method for manufacturing a display panel, characterized in that, The method is applied to the fabrication of a display panel as described in any one of claims 1-7, wherein the fabrication method comprises: A driving backplate and a light-emitting substrate are provided. A first contact pad is provided on one side of the driving backplate, and a second contact pad is provided on one side of the light-emitting substrate. On the side of the first contact pad facing away from the driving backplate, and / or on the side of the second contact pad facing away from the light-emitting substrate, a bonding adhesive is spin-coated to form a bonding adhesive layer, thereby obtaining the display panel; wherein conductive nanoparticles are dispersed within the bonding adhesive layer.

9. The method for manufacturing a display panel according to claim 8, characterized in that, After forming the bonding adhesive layer, the method further includes: The light-emitting functional layer on the light-emitting substrate is etched to obtain multiple light-emitting devices; In the same etching process, the first contact pad, the bonding adhesive layer, and the second contact pad are etched to obtain multiple contact units corresponding to the multiple light-emitting devices. Each contact unit includes the first contact pad, the bonding adhesive layer, and the second contact pad, wherein there is a gap between two adjacent contact units.

10. The method for manufacturing a display panel according to claim 9, characterized in that, The method further includes: A common electrode layer is formed on the side of the plurality of light-emitting devices opposite to the bonding adhesive layer; An auxiliary electrode is formed on the side of the common electrode layer away from the bonding adhesive layer. The orthographic projection of the auxiliary electrode on the driving backplate does not overlap with the orthographic projection of the light-emitting device on the driving backplate.

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