Light emitting device and method for preparing the same

Abstract

The present application relates to the field of display technology, and specifically discloses a light-emitting device and a method for preparing the same. The method includes: providing a first substrate; sequentially forming a buffer layer, a light-emitting layer and an anode corresponding to each pixel unit on the first substrate; forming a cathode pre-buried metal layer corresponding to each pixel unit on each buffer layer; removing the first substrate, and patterning the buffer layer on the surface of the buffer layer on one side away from the cathode pre-buried metal layer to disconnect the buffer layer corresponding to each pixel unit and expose each cathode pre-buried metal layer at the same time; forming a cathode wire layer on the exposed cathode pre-buried metal layer and extending it to the buffer layer. Compared with the conventional method of performing metal wiring of the anode and cathode on the same side of the light-emitting unit, this embodiment effectively alleviates the problem of low space utilization caused by single-sided wiring through the above-mentioned double-sided wiring method, reduces the space occupied by the gap between adjacent pixel units, and improves the pixel density.

Description

Technical Field

[0001] This invention relates to the field of display technology, and in particular to a light-emitting device and its fabrication method. Background Technology

[0002] In traditional LED flip-chip technology, the metal wiring for the anode and cathode is performed on the same side of a light-emitting unit. This inevitably creates a stepped structure on that side of the light-emitting unit. Since the epitaxial layer of an LED device has a certain thickness, typically 5 micrometers, and the etching angle of the epitaxial material is typically around 70 degrees, based on geometric relationships, if adjacent pixels need to be separated, the spacing between two columns of adjacent pixels must be at least 5 micrometers, which will prevent the achievement of a high pixel density. Summary of the Invention

[0003] Therefore, it is necessary to provide a light-emitting device and its fabrication method to address the above problems.

[0004] A method for fabricating a light-emitting device, comprising:

[0005] Provide a first substrate;

[0006] A buffer layer, a light-emitting layer corresponding to each pixel unit, and an anode are sequentially formed on the first substrate;

[0007] A cathode embedded metal layer corresponding to each pixel unit is formed on each of the buffer layers;

[0008] Remove the first substrate and pattern the buffer layer on the side of the buffer layer away from the cathode embedded metal layer to disconnect the buffer layer corresponding to each pixel unit and expose each cathode embedded metal layer.

[0009] A cathode conductor layer is formed on the exposed cathode embedded metal layer and extends to the buffer layer.

[0010] In one embodiment, prior to the step of removing the first substrate, the method for fabricating the light-emitting device further includes:

[0011] A planarization layer is formed on the buffer layer to cover each pixel unit;

[0012] A second substrate is provided and disposed on the side surface of the planarization layer away from the buffer layer.

[0013] In one embodiment, the step of disposing the second substrate on the side surface of the planarization layer away from the buffer layer includes:

[0014] An adhesive layer is formed on the planarization layer;

[0015] The second substrate is disposed on the adhesive layer.

[0016] In one embodiment, prior to the step of patterning the buffer layer, the method for fabricating the light-emitting device further includes:

[0017] Thin the buffer layer to a preset thickness.

[0018] In one embodiment, the preset thickness is between 0.2 micrometers and 1 micrometer.

[0019] In one embodiment, the difference between the preset thickness and the thickness of the light-emitting layer is between -1 micrometer and +1 micrometer.

[0020] In one embodiment, during the step of patterning the buffer layer, a portion of the surface of the cathode embedded metal layer is exposed, while another portion remains covered by the buffer layer.

[0021] In one embodiment, in the step of forming a cathode conductor layer on the exposed cathode embedded metal layer and extending to the buffer layer, the cathode conductor layer extends from the surface of the cathode embedded metal layer to the surfaces of the buffer layer on adjacent sides, and the cathode conductor layers of each pixel unit are interconnected.

[0022] In one embodiment, in the step of forming a cathode conductor layer on the exposed cathode embedded metal layer and extending to the buffer layer, the cathode conductor layer extends from the surface of the cathode embedded metal layer to the surface of the buffer layer in the corresponding pixel unit, and the cathode conductor layers of each pixel unit in the same row are not connected to each other.

[0023] In the step of sequentially forming a buffer layer, a light-emitting layer corresponding to each pixel unit, and an anode on the first substrate, the anodes of each pixel unit in the same row are interconnected.

[0024] In one embodiment, after the step of forming a cathode conductor layer on the exposed cathode embedded metal layer and extending it to the buffer layer, the method for fabricating the light-emitting device further includes:

[0025] The existing device structure is electrically connected to the driver chip.

[0026] A light-emitting device includes pixel units arranged in an array, each pixel unit including a buffer layer, a light-emitting layer, an anode, a cathode embedded metal layer and a cathode wire layer;

[0027] The buffer layer includes a first surface and a second surface. The light-emitting layer and the anode are stacked sequentially on the first surface. The cathode embedded metal layer is arranged in parallel with the light-emitting layer and is at least partially exposed outside the first surface. The cathode conductor layer extends from the surface of the exposed cathode embedded metal layer to the second surface.

[0028] In one embodiment, a planarization layer is further included, which is located on the first surface and covers each of the pixel units.

[0029] In one embodiment, the cathode conductor layer extends from the surface of the cathode embedded metal layer exposed outside the first surface to the second surface of the buffer layer on both adjacent sides, and the cathode conductor layers of each pixel unit are interconnected.

[0030] In one embodiment, the cathode conductor layer extends from the surface of the cathode embedded metal layer exposed outside the first surface to the second surface of the buffer layer in the corresponding pixel unit, and the cathode conductor layers of each pixel unit in the same row are not connected to each other;

[0031] The anode interconnection of each pixel unit in the same row.

[0032] The aforementioned light-emitting device and its fabrication method first form a light-emitting layer, an anode, and a cathode metal embedded layer on a substrate. Then, the buffer layer on the back side of the cathode metal embedded layer is patterned, the buffer layer of each pixel unit is disconnected, and the back side of the cathode metal embedded layer is exposed to form a cathode conductor layer, connecting the cathode metal embedded layer and the anode, thus achieving anode and cathode wiring. Compared to the traditional method of wiring the anode and cathode on the same side of the light-emitting unit, this embodiment effectively alleviates the problem of low space utilization caused by single-sided wiring through the above-mentioned double-sided wiring method, reduces the space occupied by the gap between adjacent pixel units, and increases pixel density. Attached Figure Description

[0033] To more clearly illustrate the technical solutions in the embodiments of this application or the conventional technology, the drawings used in the description of the embodiments or the conventional technology will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0034] Figure 1 A schematic diagram of anode and cathode wiring on one side of a light-emitting device in traditional technology;

[0035] Figure 2 A flowchart illustrating a method for fabricating a light-emitting device according to an embodiment of this application;

[0036] Figure 3-10 A schematic diagram of the fabrication method of the light-emitting device provided in the embodiments of this application;

[0037] Figure 11 This is a schematic diagram showing the electrode positions of the light-emitting device corresponding to the AM driving mode;

[0038] Figure 12 This is a schematic diagram showing the electrode positions of the light-emitting device corresponding to the PM driving method.

[0039] Explanation of reference numerals in the attached figures:

[0040] 10. First substrate; 20. Buffer layer; 30. Light-emitting layer; 40. Anode; 50. Cathode embedded metal layer; 60. Cathode wire layer; 70. Planarization layer; 80. Second substrate; 90. Adhesive layer; 100. Driver chip. Detailed Implementation

[0041] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings, which illustrate preferred embodiments of the application. However, this application may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided so that the disclosure of this application will be thorough and complete.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0043] It should be understood that when an element or layer is referred to as "on," "adjacent to," "connected to," or "coupled to" other elements or layers, it may be directly on, adjacent to, connected to, or coupled to other elements or layers, or there may be intervening elements or layers. Conversely, when an element is referred to as "directly on," "directly adjacent to," "directly connected to," or "directly coupled to" other elements or layers, there are no intervening elements or layers. It should be understood that although the terms first, second, third, etc., may be used to describe various elements, parts, regions, layers, doping types, and / or portions, these elements, parts, regions, layers, doping types, and / or portions should not be limited by these terms. These terms are only used to distinguish one element, part, region, layer, doping type, or portion from another element, part, region, layer, doping type, or portion. Therefore, without departing from the teachings of this application, the first element, component, region, layer, doping type, or portion discussed below may be represented as a second element, component, region, layer, or portion; for example, the first doping type may be referred to as the second doping type, and similarly, the second doping type may be referred to as the first doping type; the first doping type and the second doping type are different doping types, for example, the first doping type may be P-type and the second doping type may be N-type, or the first doping type may be N-type and the second doping type may be P-type.

[0044] Spatial relation terms such as “below,” “under,” “below,” “under,” “above,” “above,” etc., are used herein to describe the relationship between one element or feature shown in the figure and other elements or features. It should be understood that, in addition to the orientation shown in the figure, spatial relation terms also include different orientations of the device in use and operation. For example, if the device in the figure is flipped, the element or feature described as “below,” “under,” or “below” will be oriented “above” the other element or feature. Therefore, the exemplary terms “below” and “under” can include both above and below orientations. Furthermore, the device may also include other orientations (e.g., rotated 90 degrees or other orientations), and the spatial descriptive terms used herein will be interpreted accordingly.

[0045] When used herein, the singular forms of “a,” “an,” and “the” may also include the plural forms unless the context clearly indicates otherwise. It should also be understood that when the terms “comprise” and / or “comprising” are used in this specification, the presence of the stated feature, integer, step, operation, element, and / or part is established, but the presence or addition of one or more other features, integers, steps, operations, elements, parts, and / or groups is not excluded. Meanwhile, when used herein, the term “and / or” includes any and all combinations of the associated listed items.

[0046] Embodiments of this application are described herein with reference to cross-sectional views illustrating ideal embodiments (and intermediate structures), thus allowing for the expectation of variations in the illustrated shapes due to, for example, manufacturing techniques and / or tolerances. Therefore, embodiments of this application should not be limited to the specific shapes of the regions shown herein, but rather include shape deviations due to, for example, manufacturing techniques. For instance, implantation regions shown as rectangular typically have rounded or curved features at their edges and / or implantation concentration gradients, rather than a binary change from implantation regions to non-implantation regions. Similarly, buried regions formed by implantation can result in some implantation in the region between the buried region and the surface traversed during implantation. Therefore, the regions shown in the figures are substantially schematic, and their shapes do not represent the actual shapes of regions of the device and do not limit the scope of this application.

[0047] As described in the background section, refer to Figure 1 In traditional LED flip-chip technology, metal wiring for the anode and cathode is often performed on the same side of the light-emitting unit, thereby forming a stepped structure on one side of the light-emitting unit. Since the epitaxial layer has a certain thickness (e.g., 5 micrometers) and the etching angle of the epitaxial material is generally 70 degrees, based on geometric relationships, if it is necessary to separate adjacent pixel units, the spacing between two columns of adjacent pixel units must be at least 5 micrometers.

[0048] For example, in the PM (Passive Matrix) driving method, the cathodes of each column of pixel units are controlled by different driving signals. To avoid short circuits, the cathodes of adjacent columns of pixel units need to be disconnected. In the AM (Active Matrix) driving method, to avoid crosstalk between adjacent pixel units, the epitaxial layers (such as buffer layers) of adjacent pixel units need to be disconnected. That is, when it is necessary to disconnect the cathodes or epitaxial layers of adjacent pixel units, the spacing between adjacent pixel units needs to be maintained at more than 5 micrometers to achieve separation of adjacent pixels, making it difficult to achieve high pixel density.

[0049] Please see Figure 2 In one embodiment, this application provides a method for fabricating a light-emitting device, comprising the following steps:

[0050] Step S100: Provide a first substrate 10.

[0051] The first substrate 10 may include an alumina substrate.

[0052] Step S200: A buffer layer 20, a light-emitting layer 30 corresponding to each pixel unit, and an anode 40 are sequentially formed on the first substrate 10.

[0053] Reference Figure 3An epitaxial layer is formed on the existing first substrate 10. The epitaxial layer includes a buffer layer 20 and a light-emitting layer 30. The buffer layer 20 is deposited on the entire first substrate 10. Separated light-emitting layers 30 corresponding to each pixel unit are formed on the buffer layer 20 by a photolithography-follow-dry etching process. A corresponding anode 40 is formed on each light-emitting layer 30 by a lift-off process or a standard semiconductor photolithography-follow-etching process. The epitaxial layer material can be GaN as the main material, with Al, In, etc. as doping materials. The anode 40 material can be mainly metal, including at least one of Cr, Al, Ni, Pt, Au, etc.

[0054] Step S300: Form a cathode embedded metal layer 50 corresponding to each pixel unit on each buffer layer 20.

[0055] Reference Figure 4 After the light-emitting layer 30 and anode 40 of each pixel unit are formed, the cathode embedded metal layer 50 of each pixel unit can be formed. The cathode embedded metal layer 50 is formed on the buffer layer 20 corresponding to the interval between adjacent light-emitting layers 30. That is, in the same pixel unit, the light-emitting layer 30 and anode 40 are stacked on the buffer layer 20, and the cathode embedded metal layer 50 is arranged side by side with the stacked light-emitting layer 30 and anode 40 on the buffer layer 20.

[0056] Step S500: Remove the first substrate 10, and pattern the buffer layer 20 on the side of the buffer layer 20 away from the cathode embedded metal layer 50 to disconnect the buffer layer 20 corresponding to each pixel unit, while exposing each cathode embedded metal layer 50.

[0057] Reference Figure 6 and Figure 8 In this embodiment, the first substrate 10 can be removed using processes such as laser lift-off. Then, the wafer is flipped, and the surface of the buffer layer 20 away from the cathode embedded metal layer 50 (i.e., the surface of the buffer layer 20 originally close to the first substrate 10) is patterned. This disconnects the buffer layers 20 corresponding to each pixel unit, while exposing the surfaces of each cathode embedded metal layer 50. It should be noted that the side of the cathode embedded metal layer 50 close to the buffer layer 20 can be partially or completely exposed, while the buffer layer 20 area corresponding to the light-emitting layer 30 in each pixel unit is retained. The patterning process can include etching, etc.

[0058] Step S700: A cathode conductor layer 60 is formed on the exposed cathode embedded metal layer 50 and extends to the buffer layer 20.

[0059] Reference Figure 9 or Figure 10When the cathode embedded metal layer 50 is exposed, a cathode conductor layer 60 is formed on the exposed cathode embedded metal layer 50 and extends the cathode conductor layer 60 to the buffer layer 20, so as to form a connection path of cathode embedded metal layer 50-cathode conductor layer 60-buffer layer 20-light-emitting layer 30-anode 40 in each pixel unit. Specifically, the cathode conductor layer 60 can be fabricated by a lift-off process or by standard semiconductor photolithography followed by etching. The material of the cathode conductor layer 60 can include at least one of Cr, Al, Ni, Pt, Au, etc.

[0060] In this embodiment, a light-emitting layer 30, an anode 40, and a cathode metal embedded layer are first formed on a substrate. Then, the buffer layer 20 on the back side of the cathode metal embedded layer is patterned, disconnecting the buffer layer 20 of each pixel unit and exposing the back side of the cathode metal embedded layer to form a cathode conductor layer 60, connecting the cathode embedded metal layer 50 and the anode 40, thus achieving anode and cathode wiring. Compared to the conventional method of wiring the anode and cathode metals on the same side of the light-emitting unit, this embodiment effectively alleviates the problem of low space utilization caused by single-sided wiring through the above-mentioned double-sided wiring method, reduces the space occupied by the gap between adjacent pixel units, and improves pixel density.

[0061] In one embodiment, prior to step S500, i.e., the step of removing the first substrate 10, the fabrication method of the light-emitting device provided in this embodiment further includes:

[0062] Step S410: A planarization layer 70 is formed on the buffer layer 20 to cover each pixel unit.

[0063] Step S420: Provide a second substrate 80 and place the second substrate 80 on the side surface of the planarization layer 70 away from the buffer layer 20.

[0064] Reference Figure 5 and Figure 6 Before patterning the back side of the buffer layer 20 after removing the first substrate 10, a planarization layer 70 and a second substrate 80 can be sequentially formed on the front side of the buffer layer 20, that is, the front side of the entire light-emitting device. The planarization layer 70 makes the front side of the light-emitting device flat, and the second substrate 80 can provide a substrate for the front side of the light-emitting device to support the entire light-emitting device when the back side of the buffer layer 20 is patterned.

[0065] In the process of forming the planarization layer 70, an organic layer that completely covers each pixel unit can be formed on the buffer layer 20, and the surface of the organic material can be made flat by spin coating and baking.

[0066] In one embodiment, step S420, which involves disposing the second substrate 80 on the side of the planarization layer 70 away from the buffer layer 20, includes:

[0067] Step S421: An adhesive layer 90 is formed on the planarization layer 70.

[0068] Step S422: Deposit a second substrate 80 on the adhesive layer 90.

[0069] Reference Figure 6 After the planarization layer 70 is formed, an adhesive layer 90 can be formed on the planarization layer 70. The material of the adhesive layer 90 can be BCB (benzocyclobutene) or the like. Then, the second substrate 80 is bonded to the side of the adhesive layer 90 away from the planarization layer 70, thereby realizing the connection between the second substrate 80 and the planarization layer 70.

[0070] Once the second substrate 80 is set, the first substrate 10 can be peeled off by means of laser stripping, and then the entire light-emitting device can be flipped over, with the back side of the buffer layer 20 facing upwards, so as to perform patterning processing on the back side of the buffer layer 20.

[0071] In one embodiment, before patterning the buffer layer 20 in step S500, the method for fabricating the light-emitting device further includes thinning the buffer layer 20 to a preset thickness.

[0072] Reference Figure 7 Specifically, the buffer layer 20 can be etched across its entire surface to reduce its thickness. In this embodiment, the thickness of the buffer layer 20 can be reduced to a preset thickness before subsequent patterning. Specifically, the difference between the preset thickness and the thickness of the light-emitting layer 30 can be set to be between -1 micrometer and +1 micrometer. That is, the thickness of the buffer layer 20 is reduced to be close to the thickness of the light-emitting layer 30, making the etching depth of the buffer layer 20 similar to that of the light-emitting layer 30. This results in a symmetrical structure, which helps to achieve uniform light emission from the cathode and anode regions 40 in the pixel unit. Ideally, the preset thickness should be the same as the thickness of the light-emitting layer 30, but slight deviations may occur during actual fabrication. Therefore, in this embodiment, the deviation is limited to between -1 micrometer and +1 micrometer.

[0073] In one embodiment, the preset thickness is between 0.2 micrometers and 1 micrometer.

[0074] In one embodiment, in step S500, namely the step of patterning the buffer layer 20, a portion of the surface of the cathode embedded metal layer 50 is exposed, while another portion is still covered by the buffer layer 20.

[0075] Reference Figure 8The surface of the cathode embedded metal layer 50 is partially exposed to ensure that the cathode conductor layer 60 can be fabricated on it, while another part is left unetched. This is because the same metal in contact with different epitaxial surfaces results in a large difference in contact resistance due to the presence of the Schottky barrier. In this embodiment, the buffer layer 20 is mainly made of GaN, which is a very strong polar material. The contact resistance between the cathode embedded metal layer 50 and the buffer layer 20 is relatively small. Retaining part of the cathode embedded metal layer 50 in contact with the buffer layer 20 helps to enhance the injection of electrons from the cathode into the device.

[0076] The proportion of the exposed surface area of ​​the cathode pre-embedded metal layer 50 can be determined according to the actual process. For ease of implementation, it can generally be designed to be 50% of the exposed area, that is, half of the surface area of ​​the cathode pre-embedded metal layer 50 is covered by the buffer layer 20, and the other half is exposed.

[0077] Generally, the driving types of light-emitting devices can include AM driving and PM driving, and the electrode lead-out methods are different in the two methods.

[0078] Among them, reference Figure 11 In AM driving mode, the cathodes of each pixel unit are interconnected into a mesh, while the anodes 40 of each pixel unit are independent metal contacts.

[0079] Correspondingly, refer to Figure 9 In one embodiment, in step S700, which involves forming a cathode conductor layer 60 on the exposed cathode embedded metal layer 50 and extending it to the buffer layer 20, the cathode conductor layer 60 extends from the surface of the cathode embedded metal layer 50 to the surfaces of the buffer layers 20 on both adjacent sides, and the cathode conductor layers 60 of each pixel unit are interconnected. That is, by connecting the cathode conductor layer 60 to the buffer layers 20 of two adjacent pixel units simultaneously, the cathodes of each pixel unit are interconnected, so as to be subsequently connected to the driver chip 100 to realize an AM-driven light-emitting device.

[0080] Additionally, refer to Figure 12 In PM drive mode, the anodes 40 of each row of pixel units are interconnected, the anodes 40 of each column of pixel units are disconnected, the cathodes of each column of pixel units are interconnected, and the cathodes of each row of pixel units are disconnected.

[0081] Correspondingly, refer to Figure 10In one embodiment, in step S700, which involves forming a cathode conductor layer 60 on the exposed cathode embedded metal layer 50 and extending it to the buffer layer 20, the cathode conductor layer 60 extends from the surface of the cathode embedded metal layer 50 to the surface of the buffer layer 20 in the corresponding pixel unit. The cathode conductor layers 60 of each pixel unit in the same row are not connected to each other. That is, the cathode conductor layer 60 only extends from the corresponding cathode embedded metal layer 50 to the buffer layer 20 of the pixel unit it belongs to, and is not connected to the buffer layer 20 of adjacent pixel units, thereby keeping the cathodes of each pixel unit in the same row disconnected.

[0082] Meanwhile, in step S200, which involves sequentially forming a buffer layer 20, a light-emitting layer 30 corresponding to each pixel unit, and an anode 40 on the first substrate 10, the anodes 40 of each pixel unit in the same row are interconnected. That is, after forming the light-emitting layer 30 of each pixel unit, a common anode 40 corresponding to all pixel units in the same row can be formed on each light-emitting layer 30.

[0083] Therefore, the structure formed can be connected to the driver chip 100 to realize a light-emitting device driven by PM.

[0084] In one embodiment, after step S700, i.e., forming a cathode conductor layer 60 on the exposed cathode embedded metal layer 50 and extending it to the buffer layer 20, the fabrication method of the light-emitting device provided in this embodiment further includes:

[0085] Step S800: Electrically connect the formed device structure to the driver chip 100.

[0086] Based on the foregoing, the fabrication method of the light-emitting device provided in this embodiment can form a device structure corresponding to both AM and PM driving modes, i.e., it is compatible with both AM and PM display driving modes. Once the two types of device structures are fabricated, they can be connected to the driving chip 100 to form a light-emitting device corresponding to the AM driving mode and a light-emitting device corresponding to the PM driving mode.

[0087] Specifically, for AM driving, the second substrate 80 and adhesive layer 90 can be removed, and the planarization layer 70 can be thinned to expose the anode 40. Then, the anode 40, cathode, and other points can be bonded and interconnected with points on the driving chip 100 to form a light-emitting device corresponding to AM driving. Alternatively, for PM driving, the common anode 40 of each row of pixel units can be connected to the driving chip 100 respectively, and the common cathode of each column of pixel units can be connected to the driving chip 100 respectively to form a light-emitting device corresponding to PM driving.

[0088] It should be understood that although the steps in the flowcharts of the above embodiments are shown sequentially according to the arrows, these steps are not necessarily executed in the order indicated by the arrows. Unless explicitly stated herein, there is no strict order restriction on the execution of these steps, and they can be executed in other orders. Moreover, at least some steps in the flowcharts of the above embodiments may include multiple steps or multiple stages. These steps or stages are not necessarily completed at the same time, but can be executed at different times. The execution order of these steps or stages is not necessarily sequential, but can be performed alternately or in turn with other steps or at least some of the steps or stages of other steps.

[0089] Please continue referring to the figures. In another embodiment, this application also provides a light-emitting device, see reference... Figure 9 and Figure 10 It includes pixel units arranged in an array, each pixel unit including a buffer layer 20, a light-emitting layer 30, an anode 40, a cathode embedded metal layer 50, and a cathode wire layer 60.

[0090] The buffer layer 20 includes a first surface and a second surface. The light-emitting layer 30 and the anode 40 are stacked sequentially on the first surface. The cathode pre-embedded metal layer 50 is arranged in parallel with the light-emitting layer 30 and is at least partially exposed outside the first surface. The cathode wire layer 60 extends from the surface of the exposed cathode pre-embedded metal layer 50 to the second surface.

[0091] Compared to the traditional method of wiring the anode and cathode on the same side of the light-emitting unit, the light-emitting device provided in this embodiment effectively alleviates the problem of low space utilization caused by single-sided wiring by using the above-mentioned double-sided wiring method, reduces the space occupied by the gap between adjacent pixel units, and improves the pixel density.

[0092] In one embodiment, a planarization layer 70 is also included, which is located on the first surface and covers each pixel unit.

[0093] In one embodiment, the cathode conductor layer 60 extends from the surface of the cathode embedded metal layer 50 exposed outside the first surface to the second surface of the buffer layer 20 on both adjacent sides, and the cathode conductor layers 60 of each pixel unit are interconnected.

[0094] In one embodiment, reference Figure 10 The cathode conductor layer 60 extends from the surface of the cathode embedded metal layer 50 exposed outside the first surface to the second surface of the buffer layer 20 in the corresponding pixel unit. The cathode conductor layers 60 of each pixel unit in the same row are not connected to each other.

[0095] The anodes 40 of each pixel unit in the same row are interconnected.

[0096] The light-emitting device provided in this embodiment and the method for preparing the light-emitting device provided in the previous embodiment belong to the same inventive concept. For details about the light-emitting device, please refer to the detailed description of the preparation method of the light-emitting device, which will not be repeated here.

[0097] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0098] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this application should be determined by the appended claims.

Claims

1. A method for preparing a light-emitting device, characterized in that: include: providing a first substrate; A buffer layer, a light-emitting layer corresponding to each pixel unit and an anode are sequentially formed on the first substrate; forming a cathode pre-buried metal layer corresponding to each pixel unit on each of the buffer layers; The first substrate is removed, and the buffer layer is patterned on a surface of the buffer layer on a side away from the cathode pre-buried metal layer, so as to disconnect the buffer layer corresponding to each pixel unit and expose each cathode pre-buried metal layer; A cathode wire layer is formed on the exposed cathode pre-buried metal layer and extends to the buffer layer.

2. The method for preparing a light emitting device according to claim 1, characterized in that: Before the step of removing the first substrate, the method for preparing the light emitting device further includes: forming a planarization layer on the buffer layer to cover each of the pixel units; A second substrate is provided, and the second substrate is disposed on a surface of the planarization layer that is away from the buffer layer.

3. The method for preparing a light emitting device according to claim 2, characterized in that: The step of disposing the second substrate on a surface of the planarization layer away from the buffer layer comprises: forming an adhesive layer on the planarization layer; The second substrate is disposed on the adhesive layer.

4. The method for preparing a light emitting device according to claim 1, characterized in that: Before the step of patterning the buffer layer, the method for preparing the light emitting device further includes: The buffer layer is thinned to a preset thickness.

5. The method for preparing a light emitting device according to claim 4, characterized in that: The preset thickness is between 0.2 micrometers and 1 micrometer.

6. The method for preparing a light emitting device according to claim 4, characterized in that: The difference between the preset thickness and the thickness of the light-emitting layer is between -1 micrometer and +1 micrometer.

7. The method for preparing a light emitting device according to claim 1, characterized in that: In the step of patterning the buffer layer, a portion of the surface of the cathode pre-buried metal layer is exposed, and another portion is still covered with the buffer layer.

8. The method for preparing a light emitting device according to claim 1, characterized in that: In the step of forming a cathode wire layer on the exposed cathode pre-buried metal layer and extending it to the buffer layer, the cathode wire layer extends from the surface of the cathode pre-buried metal layer to the surfaces of the buffer layers on two adjacent sides, and the cathode wire layers of each pixel unit are interconnected.

9. The method for preparing a light emitting device according to claim 1, characterized in that: In the step of forming a cathode wire layer on the exposed cathode pre-buried metal layer and extending it to the buffer layer, the cathode wire layer extends from the surface of the cathode pre-buried metal layer to the surface of the buffer layer in the corresponding pixel unit, and the cathode wire layers of the pixel units in the same row are not connected to each other; In the step of sequentially forming a buffer layer, a light-emitting layer corresponding to each pixel unit, and an anode on the first substrate, the anodes of the pixel units in the same row are interconnected.

10. The method for preparing a light emitting device according to claim 8 or 9, characterized in that: After the step of forming a cathode wire layer on the exposed cathode pre-buried metal layer and extending the cathode wire layer to the buffer layer, the method for preparing the light emitting device further includes: The formed device structure is electrically connected to the driving chip.

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