An LED display device

Abstract

This application discloses an LED display device, belonging to the field of display technology. When the LED display device disclosed in this application is operating normally, in the first current diffusion layer near the first electrode layer where the pixel electrodes are disposed, the lateral current diffusion length is less than or equal to half the shortest distance between the edges of adjacent pixel electrodes. This prevents the operating current of each pixel corresponding to a pixel electrode from diffusing to adjacent pixels. In other words, the active layer of each pixel can be independently controlled to emit light. Thus, on a large-size LED chip, self-isolation of each pixel is achieved by adjusting the lateral current diffusion length, eliminating the need for etching to achieve isolation between pixels. This avoids the negative effects caused by etching damage, thereby improving the reliability and yield of the LED display device and reducing the probability of leakage.

Description

Technical Field

[0001] This application relates to the field of display technology, and in particular to an LED display device. Background Technology

[0002] Micro-LED technology miniaturizes and matrixes traditional LEDs. It first shrinks large-size LED chips to micrometer-level Micro-LED chips, then matrixes them into a high-density integrated LED array. This allows each pixel in a Micro-LED display to be independently positioned and illuminated, enabling precise control of each Micro-LED chip and thus achieving display functionality. Current technologies typically employ etching processes to control chip size, leading to etching damage and problems such as leakage, decreased reliability, and reduced yield. Furthermore, as Micro-LED chip sizes shrink, the proportion of the etched chip sides to the total chip surface area increases, amplifying the negative impact of etching damage. Summary of the Invention

[0003] The main technical problem addressed by this application is to provide an LED display device that can improve the reliability and yield of LED display devices and reduce the probability of leakage.

[0004] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide an LED display device, the LED display device comprising a light-emitting epitaxial wafer, the light-emitting epitaxial wafer comprising:

[0005] Active layer;

[0006] The first current diffusion layer and the second current diffusion layer are respectively disposed on opposite sides of the active layer;

[0007] A first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on the side of the first current diffusion layer away from the active layer, and the second electrode layer is disposed on the side of the second current diffusion layer away from the active layer, and the first electrode layer includes a plurality of pixel electrodes arranged in an array.

[0008] The thickness and resistivity of the first current diffusion layer are set such that, when the LED display device is operating normally, the lateral current diffusion length of the first current diffusion layer satisfies... Where Ls is the lateral current diffusion length of the first current diffusion layer, and D1 is the shortest distance between the edges of adjacent pixel electrodes.

[0009] The lateral current diffusion length Ls of the first current diffusion layer is calculated using the following formula:

[0010]

[0011] Where k is Boltzmann constant, T is thermodynamic temperature, e is electron charge, t is the thickness of the first current diffusion layer, ρ is the resistivity of the first current diffusion layer, and J0 is the current density in the first current diffusion layer covered by the pixel electrode when the LED display device is working normally.

[0012] The resistivity of the first current diffusion layer is greater than or equal to 0.1 Ω·cm.

[0013] The thickness of the first current diffusion layer is less than or equal to 1 μm.

[0014] Wherein, the resistivity of the first current diffusion layer is greater than or equal to 0.5 Ω·cm, and the thickness of the first current diffusion layer is less than or equal to 0.5 μm.

[0015] Wherein, the resistivity of the first current diffusion layer is greater than or equal to 1 Ω·cm, and the thickness of the first current diffusion layer is less than or equal to 0.1 μm.

[0016] in,

[0017] Where D1≤20μm.

[0018] in, Where D2 is the distance between the geometric centers of the adjacent pixel electrodes.

[0019] The LED display device further includes a driving backplane, which includes a backplane body and a plurality of switching devices arranged in an array on the backplane body. Each pixel electrode is electrically connected to the corresponding switching device so that the connected switching device provides a driving signal.

[0020] Wherein, the driving backplate is bonded and fixed to the light-emitting epitaxial wafer; the pixel electrode is formed on the backplate body and forms a conductive contact with the first current diffusion layer when the driving backplate is bonded and fixed to the light-emitting epitaxial wafer; or, the pixel electrode is formed on the first current diffusion layer, and the driving backplate further includes a plurality of bonding electrodes arranged in an array on the backplate body, each of the bonding electrodes being electrically connected to the corresponding switching device and aligned and bonded to the corresponding pixel electrode.

[0021] The driving backplate is formed on one side of the light-emitting epitaxial wafer by growth; the pixel electrode is formed on the first current diffusion layer; when the driving backplate is formed by growth, the switching device is grown and formed corresponding to the position of the pixel electrode; the LED display device further includes a backplate substrate located on the side of the backplate body away from the pixel electrode, and is bonded and fixed to the backplate body.

[0022] In this configuration, one of the first current diffusion layer and the second current diffusion layer is an N-type semiconductor layer, and the other is a P-type semiconductor layer. The second electrode layer is a common electrode layer.

[0023] To solve the above-mentioned technical problems, one technical solution adopted in this application is: to provide an LED display device, the LED display device comprising a light-emitting epitaxial wafer, the light-emitting epitaxial wafer comprising:

[0024] Active layer;

[0025] The first current diffusion layer and the second current diffusion layer are respectively disposed on opposite sides of the active layer;

[0026] A first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on the side of the first current diffusion layer away from the active layer, and the second electrode layer is disposed on the side of the second current diffusion layer away from the active layer, and the first electrode layer includes a plurality of pixel electrodes arranged in an array.

[0027] The thickness and resistivity of the first current diffusion layer are set such that when a normal operating voltage is applied to each pixel electrode and the second electrode layer respectively, the light generated in the area covered by each pixel electrode has a first luminous intensity, and the light generated in the area covered by the lateral diffusion current generated by each pixel electrode in the adjacent pixel electrode has a second luminous intensity, and the ratio of the first luminous intensity to the second luminous intensity is greater than or equal to 10.

[0028] Wherein, the thickness of the first current diffusion layer is less than or equal to 1 μm, and the resistivity of the first current diffusion layer is greater than or equal to 0.1 Ω·cm.

[0029] Wherein, the ratio of the first luminous intensity to the second luminous intensity is greater than or equal to 20.

[0030] The shortest distance between the edge of each pixel electrode and the edge of other adjacent pixel electrodes is less than or equal to 10 μm.

[0031] The beneficial effects of this application are as follows: Unlike the prior art, in the LED display device of this application, when the LED display device is working normally, the lateral current diffusion length in the first current diffusion layer near the first electrode layer where the pixel electrodes are disposed is less than or equal to half of the shortest distance between the edges of adjacent pixel electrodes. This ensures that the operating current of each pixel corresponding to each pixel electrode will not diffuse to adjacent pixels. In other words, the active layer of each pixel can be independently controlled to emit light. Thus, on a large-size LED chip, self-isolation of each pixel can be achieved by adjusting the lateral current diffusion length, eliminating the need for etching to achieve isolation between pixels. This avoids the negative effects caused by etching damage, thereby improving the reliability and yield of the LED display device and reducing the probability of leakage. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments 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. Among them:

[0033] Figure 1 This is a schematic diagram of the structure of one embodiment of the LED display device of this application;

[0034] Figure 2 A schematic diagram of one embodiment of the drive backplate;

[0035] Figure 3 This is a schematic diagram of one embodiment of the extensional structure;

[0036] Figure 4 A schematic diagram of a temporary bonding implementation of an epitaxial structure;

[0037] Figure 5 A schematic diagram of a structure in which the epitaxial structure and the driving backplate are bonded together;

[0038] Figure 6 This is a schematic diagram of another embodiment of the extensional structure;

[0039] Figure 7 A schematic diagram of another embodiment of bonding the epitaxial structure to the drive backplate;

[0040] Figure 8 This is a schematic diagram of another embodiment of the LED display device of this application;

[0041] Figure 9 A schematic diagram of a structure for one embodiment of a growth-driven backplate;

[0042] Figure 10This is a schematic diagram of another embodiment of the LED display device of this application. Detailed Implementation

[0043] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0044] Please see Figure 1 , Figure 1 This is a schematic diagram of an embodiment of the LED display device of this application. The LED display device includes a light-emitting epitaxial wafer 100, which further includes an active layer 11, a first current diffusion layer 12, a second current diffusion layer 13, a first electrode layer 14, and a second electrode layer 15. The first current diffusion layer 12 and the second current diffusion layer 13 are respectively disposed on opposite sides of the active layer 11. The first electrode layer 14 is disposed on the side of the first current diffusion layer 12 facing away from the active layer 11, and the second electrode layer 15 is disposed on the side of the second current diffusion layer 13 facing away from the active layer 11. The first electrode layer 14 includes a plurality of pixel electrodes 141 arranged in an array, with one pixel electrode 141 corresponding to one pixel. The pixel electrodes 141 are electrically connected to a driving backplane, receive driving signals from the driving backplane, and control the corresponding active layer 11 to emit light. Figure 1 The arrows in the diagram indicate that each individual pixel emits light.

[0045] In this design, one of the first current diffusion layer 12 and the second current diffusion layer 13 is an N-type semiconductor layer, and the other is a P-type semiconductor layer, formed by doping semiconductor materials such as AlN, AlGaN, GaN, InGaN, AlInGaN, GaAs, GaP, GaAsP, AlGaAs, and AlGaInP. For example, the first current diffusion layer 12 is an N-type semiconductor layer, and the second current diffusion layer 13 is a P-type semiconductor layer; or, the first current diffusion layer 12 is a P-type semiconductor layer, and the second current diffusion layer 13 is an N-type semiconductor layer. The fabrication process for the LED display device of this application differs depending on the two different structures, as will be described below. The active layer 11, the first current diffusion layer 12, and the second current diffusion layer 13 can all be formed by epitaxial growth processes.

[0046] The second electrode layer 15 is a common electrode layer, such as a common electrode layer formed of materials like Al, Cr, or ITO. Preferably, the second electrode layer 15 is a transparent layer and serves as the light-emitting surface of the light-emitting epitaxial wafer 100. When the first electrode layer 14 and the second electrode layer 15 are connected to a working voltage, holes from the P-type semiconductor layer and electrons from the N-type semiconductor layer recombine in the active layer 11 to emit light. The emission wavelength is determined by the energy band structure of the semiconductor material.

[0047] The thickness and resistivity of the first current diffusion layer 12 are set such that, when the LED display device is operating normally, the lateral current diffusion length of the first current diffusion layer 12 satisfies... Where Ls is the lateral current diffusion length of the first current diffusion layer 12, and D1 is the shortest distance between the edges of adjacent pixel electrodes 141. Figure 1 schematic drawing The situation.

[0048] The thickness of the first current diffusion layer 12 in the spacing region between the pixel electrodes 141 can be uniform, meaning that no etching process is performed after the first current diffusion layer 12 with a preset thickness and preset resistivity is formed. Of course, the thickness of the first current diffusion layer 12 in the spacing region between the pixel electrodes 141 can also be inconsistent. After the first current diffusion layer 12 with a preset thickness and preset resistivity is formed, other structural features can be formed using processes such as etching. This application does not limit this.

[0049] As can be seen, the operating current of each pixel corresponding to pixel electrode 141 will not diffuse to adjacent pixels. In other words, the active layer 11 of each pixel can be independently controlled to emit light. This allows for self-isolation of pixels on a large-size LED chip by adjusting the lateral current diffusion length, eliminating the need for etching to achieve pixel isolation. This avoids the negative effects of etching damage, thereby improving the reliability and yield of LED display devices and reducing the probability of leakage. Furthermore, the implementation of self-isolation simplifies the chip manufacturing process and reduces production costs.

[0050] In one implementation, please refer to [link / reference needed]. Figure 1 The lateral current diffusion length Ls of the first current diffusion layer 12 is calculated by the following formula (1):

[0051]

[0052] Where k is Boltzmann constant, T is thermodynamic temperature, e is electron charge, t is thickness of the first current diffusion layer 12, ρ is resistivity of the first current diffusion layer 12, and J0 is current density within the first current diffusion layer 12 covered by the pixel electrode 141 when the LED display device is operating normally. It can be seen that the lateral current diffusion length Ls decreases as the thickness t of the first current diffusion layer 12 decreases and as the resistivity ρ of the first current diffusion layer 12 increases. To prevent the operating current of each pixel corresponding to the pixel electrode 141 from diffusing to adjacent pixels, the lateral current diffusion length Ls needs to be reduced.

[0053] This embodiment achieves this by limiting the resistivity ρ of the first current diffusion layer 12 to be greater than or equal to 0.1 Ω·cm, and by adjusting the thickness t and the current density J0. Or other smaller sizes, such as resistivity ρ of 0.1Ω·cm, 0.3Ω·cm, 0.5Ω·cm, 0.7Ω·cm, 1Ω·cm, etc., can be achieved by adjusting the parameters of the epitaxial growth process.

[0054] In one embodiment, this can also be achieved by limiting the thickness t of the first current diffusion layer 12 to be less than or equal to 1 μm. For example, thicknesses t can be 1μm, 0.8μm, 0.6μm, 0.4μm, 0.2μm, 0.1μm, etc., which can be achieved by adjusting the parameters of the epitaxial growth process.

[0055] In one embodiment, this can also be achieved by simultaneously limiting the resistivity ρ of the first current diffusion layer 12 to be greater than or equal to 0.5 Ω·cm and the thickness t of the first current diffusion layer 12 to be less than or equal to 0.5 μm. For example, the resistivity ρ can be 0.5Ω·cm, 0.8Ω·cm, 1.2Ω·cm, 1.5Ω·cm, 1.8Ω·cm, etc., while the thickness t can be 0.5μm, 0.4μm, 0.3μm, 0.2μm, 0.1μm, etc., which can be achieved by adjusting the parameters of the epitaxial growth process.

[0056] In one embodiment, this can also be achieved by simultaneously limiting the resistivity ρ of the first current diffusion layer 12 to be greater than or equal to 1 Ω·cm and the thickness t of the first current diffusion layer 12 to be less than or equal to 0.1 μm. For example, the resistivity ρ can be 1Ω·cm, 1.2Ω·cm, 1.4Ω·cm, 1.6Ω·cm, 2Ω·cm, etc., while the thickness t can be 0.1μm, 0.08μm, 0.06μm, 0.04μm, etc., which can be achieved by adjusting the parameters of the epitaxial growth process.

[0057] It is worth noting that the resistivity of a semiconductor layer is generally controlled by the doping rate; generally, the higher the doping rate, the lower the resistivity (and thus the higher the conductivity). In the above embodiment, the resistivity of the first current diffusion layer 12 is much greater than that of the semiconductor used in conventional LEDs, meaning a lower doping rate is required. This does not increase the manufacturing difficulty of the LED; on the contrary, it reduces it. Furthermore, the thickness of the first current diffusion layer 12 is also much smaller than that of the semiconductor used in conventional LEDs, thereby reducing material costs.

[0058] In one embodiment, to further ensure that the operating current of the pixel corresponding to each pixel electrode 141 does not diffuse to adjacent pixels, the lateral current diffusion length of the first current diffusion layer 12 is limited. The working current of two adjacent pixel electrodes 141 can diffuse to the farthest point of the pixel at a distance of at least D1 / 3, or even D1 / 5, D1 / 10 or smaller, so that each pixel can be independently controlled to emit light without the need for isolation through etching process.

[0059] In one embodiment, the shortest spacing D1 between the edges of adjacent pixel electrodes 141 is ≤20μm, such as 20μm, 18μm, 16μm, 14μm, 12μm, 10μm, 5μm, 1μm, etc., which can meet the pixel density requirements of LED display devices without the need for isolation through etching processes.

[0060] In one embodiment, the LED display device of this application also satisfies: Where D2 is the distance between the geometric centers of adjacent pixel electrodes. This ensures that the minimum distance D1 between the edges of adjacent pixel electrodes 141 is not too small, which would make it difficult to control the lateral current diffusion length of the first current diffusion layer 12. This also prevents D1 from being too large, which would result in too low pixel density and reduce display quality.

[0061] In one implementation, please refer to [link / reference needed]. Figure 1 The LED display device of this application further includes a driving backplate 200, which includes a backplate body 21 and a plurality of switching devices (not shown) arranged in an array on the backplate body 21. The driving backplate 200 is bonded and fixed to the light-emitting epitaxial film 100, and each pixel electrode 141 is electrically connected to the corresponding switching device so that the connected switching device provides a driving signal. That is, there is a one-to-one correspondence between the switching device and the pixel electrode 141.

[0062] In the process of fabricating the LED display device, the pixel electrode 141 can first be formed on the backplate body 21 corresponding to the switching device, and form a conductive contact with the first current diffusion layer 12 when the driving backplate 200 is bonded and fixed to the light-emitting epitaxial wafer 100, that is, the pixel electrode 141 and the first current diffusion layer 12 are bonded and fixed. The driving signal is directly transmitted from the switching device to the corresponding pixel electrode 141, thereby controlling the active layer 11 covered by the pixel electrode 141 to emit light, while satisfying the requirements of the switching device. Based on this, individual control of each pixel can be achieved. Furthermore, the alignment process can be reduced during fabrication, improving process yield.

[0063] In other embodiments, the pixel electrode 141 can also be directly formed on the first current diffusion layer 12. In this case, the driving backplane 200 further includes a plurality of bonding electrodes arranged in an array on the backplane body 21. Each bonding electrode is electrically connected to a corresponding switching device and is aligned and bonded to the corresponding pixel electrode 141. The driving signal is transmitted from the switching device through the bonding electrode to the corresponding pixel electrode 141, thereby controlling the active layer 11 covered by the pixel electrode 141 to emit light, while satisfying the requirements... Based on this, individual control of each pixel is achieved.

[0064] The following describes the fabrication process of the LED display device of this application in two cases: the first current diffusion layer 12 is an N-type semiconductor layer and a P-type semiconductor layer. In both cases, the pixel electrode 141 and the corresponding switching device are formed on the back plate body 21, and the driving back plate 200 and the light-emitting epitaxial film 100 are fixed by bonding.

[0065] First, a driver backplane is required for all of them. Please refer to [link / reference]. Figure 2 , Figure 2 This is a schematic diagram of one embodiment of the driving backplate. The driving backplate 200 includes a backplate body 21 and a plurality of switching devices (not shown) arranged in an array on the backplate body 21. The plurality of pixel electrodes 141 arranged in an array in the first electrode layer 14 are also pre-connected to the corresponding switching devices. The backplate contact metal on the surface of the backplate body 21 facing the light-emitting epitaxial wafer 100 is preferably made of materials or alloys such as AlGe, Cr, Ti, Pt, Au, and Sn, with AlGe being the most suitable material due to its high reflectivity. This metal is used to reflect light from the light-emitting epitaxial wafer 100 toward the backplate body 21 to the light-emitting surface.

[0066] Additionally, the extensional structure also needs to be provided; please refer to... Figure 2 See Figure 3 , Figure 3This is a schematic diagram of an embodiment of the epitaxial structure 300. The epitaxial structure 300 includes a substrate 31, a buffer layer 32, a first current diffusion layer 12, an active layer 11, and a second current diffusion layer 13, wherein the first current diffusion layer 12 is an N-type semiconductor layer and the second current diffusion layer 13 is a P-type semiconductor layer. Specifically, the buffer layer 32, the first current diffusion layer 12, the active layer 11, and the second current diffusion layer 13 are sequentially formed on the substrate 31 using an epitaxial process. The buffer layer 32 is used to reduce the adverse effects caused by lattice mismatch between the substrate 31 and the N-type semiconductor layer. When forming the first current diffusion layer 12, its thickness t and resistivity ρ need to be designed according to the size information of the driving backplate 200, so that the lateral current diffusion length of the first current diffusion layer 12 meets the requirements. Where Ls is the lateral current diffusion length of the first current diffusion layer 12, and D1 is the shortest distance between the edges of adjacent pixel electrodes 141.

[0067] Next, a second electrode layer 15, such as a transparent electrode ITO, is formed on one side surface of the second current diffusion layer 13 of the epitaxial structure 300. (See [link to documentation]). Figure 4 , Figure 4 This is a schematic diagram of an embodiment of temporary bonding of the epitaxial structure. The epitaxial structure 300 is then transferred from the second electrode layer 15 side to the temporary substrate 42 via the temporary bonding layer 41. The temporary bonding layer 41 can be formed of a thermoplastic material and can be removed subsequently by high-temperature pyrolysis. Next, the substrate 31 is removed by grinding, chemical etching, laser lift-off, etc., and the buffer layer 32 is removed by dry or wet etching.

[0068] Furthermore, please combine Figure 1 and Figure 4 See Figure 5 , Figure 5 This is a schematic diagram of an embodiment where the epitaxial structure is bonded to the driving backplane. The epitaxial structure 300, with the substrate 31 and buffer layer 32 removed, is bonded to the driving backplane 200 from the first current diffusion layer 12 side, specifically to the pixel electrode 141 formed on the switching device, and an ohmic contact is formed by high-temperature annealing. Then, the temporary substrate 42 and temporary bonding layer 41 are removed by high-temperature pyrolysis to obtain the LED display device of this application.

[0069] In another case, please refer to Figure 6 , Figure 6 This is a schematic diagram of another embodiment of the epitaxial structure. The epitaxial structure 300 includes a substrate 31, a buffer layer 32, the aforementioned second current diffusion layer 13, an active layer 11, and a first current diffusion layer 12, wherein the second current diffusion layer 13 is an N-type semiconductor layer and the first current diffusion layer 12 is a P-type semiconductor layer.

[0070] Then, the epitaxial structure 300 is bonded directly to the driving backplane 200 from the P-type semiconductor layer (i.e., the first current diffusion layer 12), specifically to the pixel electrode 141 formed on the switching device, and an ohmic contact is formed by high-temperature annealing. See details in [link to relevant documentation]. Figure 7 , Figure 7 This is a schematic diagram of another embodiment of the bonding of the epitaxial structure to the drive backplane.

[0071] Next, the substrate 31 and the buffer layer 32 are removed sequentially, and a second electrode layer 15, such as a transparent electrode ITO, is formed on one side of the second current diffusion layer 13. To form an ohmic contact, an Al or Cr conductive layer with a thickness of less than 5 nm can be formed between the ITO and the N-type semiconductor layer (i.e., the second current diffusion layer 13), thereby obtaining the LED display device of this application. For details, please refer to the relevant reference. Figure 1 and Figure 7 .

[0072] In one implementation, please refer to Figure 8 , Figure 8 This is a schematic diagram of another embodiment of the LED display device of this application, and... Figure 1 The LED display device shown is the same as the one in this embodiment. The LED display device includes a light-emitting epitaxial wafer 100, which in turn includes an active layer 11, a first current diffusion layer 12, a second current diffusion layer 13, a first electrode layer 14, and a second electrode layer 15. Figure 8 The arrows in the diagram indicate that each individual pixel emits light.

[0073] Similar to the above embodiments, the thickness and resistivity of the first current diffusion layer 12 are set such that, when the LED display device is operating normally, the lateral current diffusion length of the first current diffusion layer 12 satisfies Where Ls is the lateral current diffusion length of the first current diffusion layer 12, and D1 is the shortest distance between the edges of adjacent pixel electrodes 141. In other words, the active layer 11 of each pixel can be independently controlled to emit light, thereby achieving self-isolation of each pixel on a large-size LED chip by adjusting the lateral current diffusion length. Isolation between pixels is achieved without etching, avoiding the negative effects of etching damage, thus improving the reliability and yield of LED display devices and reducing the probability of leakage. Furthermore, the implementation of self-isolation simplifies the chip manufacturing process and reduces production costs.

[0074] Specifically, the LED display device can have the above-mentioned characteristics by controlling the thickness and resistivity of the first current diffusion layer 12, as described in the above embodiments, which will not be repeated here.

[0075] In one implementation, please refer to [link / reference needed]. Figure 8The LED display device further includes a driving backplane 200, which includes a backplane body 21 and a plurality of switching devices 22 arranged in an array on the backplane body 21. The driving backplane 200 is formed on one side of the light-emitting epitaxial wafer 100 by growth, and each pixel electrode 141 is electrically connected to the corresponding switching device 22 so that the connected switching device 22 provides a driving signal. That is, there is a one-to-one correspondence between the switching device 22 and the pixel electrode 141.

[0076] The pixel electrode 141 is formed on the first current diffusion layer 12. When the driving backplate 200 is formed by growth, the switching device 22 is grown and formed corresponding to the position of the pixel electrode 141.

[0077] The LED display device further includes a backplane substrate 201 and a bonding material layer 202. The backplane substrate 201 is located on the side of the backplane body 21 away from the pixel electrode 141 and is bonded and fixed to the backplane body 21, that is, it is disposed on the side of the backplane body 21 away from the pixel electrode 141 by the bonding material layer 202.

[0078] The following explanation uses the first current diffusion layer 12 as an example, which is a P-type semiconductor layer. Figure 8 The manufacturing process of the LED display device is shown.

[0079] First, provide, such as Figure 6 The diagram shows an epitaxial structure 300, which includes a substrate 31, a buffer layer 32, and the aforementioned second current diffusion layer 13, active layer 11, and first current diffusion layer 12. The second current diffusion layer 13 is an N-type semiconductor layer, and the first current diffusion layer 12 is a P-type semiconductor layer. Specifically, the buffer layer 32, the second current diffusion layer 13, the active layer 11, and the first current diffusion layer 12 are epitaxially grown sequentially on the substrate 31. Then, pixel electrodes 141 arranged in an array are formed on the first current diffusion layer 12. The pixel electrodes 141 form an ohmic contact with the first current diffusion layer 12 and also include a highly reflective surface to reflect light emitted from the active layer 11 toward the pixel electrodes 141 in the light-emitting direction.

[0080] Then, please combine Figure 6 and Figure 8 See Figure 9 , Figure 9This is a schematic diagram of one embodiment of the growth and formation of a driving backplane. A backplane body 21 and a switching device 22 of the driving backplane 200 are grown and formed on one side of the pixel electrode 141, wherein the switching device 22 corresponds to the position of the pixel electrode 141. The backplane body 21 includes an insulating layer 211 and a polysilicon layer 212. The insulating layer 211 is used to isolate the multiple pixel electrodes 141 and to isolate the first current diffusion layer 12 from the polysilicon layer 212. The polysilicon layer 212 includes the functional layers forming the TFTs, as in the prior art, and will not be described again here. A bonding material layer 202 is used to bond and fix the driving backplane 200 to the backplane substrate 201 on one side of the driving backplane 200, thereby supporting the other layers and improving the strength and lifespan of the LED display device.

[0081] Then, please combine Figure 9 Continue reading Figure 8 ,Will Figure 9 The structure is flipped, and the substrate 31 is removed by grinding, chemical etching, laser lift-off, etc., and the buffer layer 32 is removed by dry or wet etching. Next, a second electrode layer 15, such as a transparent electrode ITO, is formed on one side of the second current diffusion layer 13, resulting in... Figure 8 The LED display device shown.

[0082] Of course, the first current diffusion layer 12 can also be an N-type semiconductor layer. The preparation process can be found in the above embodiments, and will not be illustrated in detail here.

[0083] In one implementation, please refer to Figure 10 , Figure 10 This is a schematic diagram of another embodiment of the LED display device of this application. Figure 1 Based on the structure shown, the LED display device in this embodiment also includes a light-blocking element 500 located between adjacent pixel electrodes 141. As mentioned earlier, the light emission of each pixel corresponding to each pixel electrode 141 can be independently controlled, but light crosstalk may occur between adjacent pixels, affecting the display effect. The light-blocking element 500 has a highly reflective surface, which can reflect the light that is about to enter the area of ​​the adjacent pixel back to the current pixel area, thereby improving the light crosstalk phenomenon and enhancing the display effect.

[0084] The light-blocking component 500 can be made directly from a highly reflective metal, or an insulating transparent dielectric layer can be formed first, and then a highly reflective metal can be plated to cover the surface of the dielectric layer. The shape of the light-blocking component 500 can be rectangular, trapezoidal, triangular, etc., which can improve light crosstalk while also adjusting the light emission angle. Figure 10 Draw one of the scenarios schematically.

[0085] For further information, please refer to [link / reference]. Figure 10The LED display device of this application also includes an adjustment element 600, located between adjacent light-blocking elements 500, that is, set for each pixel. Specifically, it can be formed by using SU8 material (a negative epoxy photoresist) to form a lens, which can improve the light emission angle of each pixel and increase the light emission efficiency.

[0086] Of course, the aforementioned light-blocking component 500 and adjusting component 600 can also be provided in... Figure 8 The LED display device shown achieves the goals of improving light crosstalk, enhancing display effect, improving light emission angle, and increasing light emission efficiency. Further illustrations are not provided here.

[0087] In one implementation, please refer to [link / reference needed]. Figure 1 Similar to the embodiments described above, in this embodiment, the LED display device also includes an active layer 11, a first current diffusion layer 12, a second current diffusion layer 13, a first electrode layer 14, and a second electrode layer 15. The first current diffusion layer 12 and the second current diffusion layer 13 are respectively disposed on opposite sides of the active layer 11. The first electrode layer 14 is disposed on the side of the first current diffusion layer 12 facing away from the active layer 11, and the second electrode layer 15 is disposed on the side of the second current diffusion layer 13 facing away from the active layer 11. The first electrode layer 14 includes a plurality of pixel electrodes 141 arranged in an array, with one pixel electrode 141 corresponding to one pixel.

[0088] The thickness and resistivity of the first current diffusion layer 12 are set such that when a normal operating voltage is applied to each pixel electrode 141 and the second electrode layer 15 respectively, the light generated in the area covered by each pixel electrode 141 has a first luminous intensity E1, and the light generated in the area covered by the lateral diffusion current generated by each pixel electrode 141 in the adjacent pixel electrode 141 has a second luminous intensity E2. The ratio of the first luminous intensity E1 to the second luminous intensity E2, E1 / E2, is greater than or equal to 10, for example, E1 / E2 is 10, 15, 20, 30, 50, etc.

[0089] The current within the first current diffusion layer 12 covered by the pixel electrode 141 diffuses laterally. The area where the current diffuses generates light of a preset wavelength, and the greater the distance of current diffusion, the weaker the light intensity. This embodiment limits E1 / E2 to ≥ 10, making the light intensity generated by the current diffused from the current pixel to adjacent pixels negligible. This achieves self-isolation between pixels, allowing the emission of each pixel to be controlled individually. Therefore, this embodiment eliminates the need for etching to achieve isolation between pixels, avoiding the negative effects of etching damage, improving the reliability and yield of LED display devices, and reducing the probability of leakage. Furthermore, the self-isolation simplifies the chip manufacturing process and reduces production costs.

[0090] At this point, the resistivity and thickness of the first current diffusion layer 12 can also be limited in various ways as described above. For example, the thickness of the first current diffusion layer 12 can be limited to less than or equal to 1 μm, such as 1 μm, 0.8 μm, 0.6 μm, 0.4 μm, 0.2 μm, 0.1 μm, etc., and the resistivity of the first current diffusion layer 12 can be greater than or equal to 0.1 Ω·cm, such as 0.1 Ω·cm, 0.3 Ω·cm, 0.5 Ω·cm, 0.7 Ω·cm, 1 Ω·cm, etc., to achieve E1 / E2≥10. Specifically, this can be achieved by adjusting the parameters of the epitaxial growth process for forming the first current diffusion layer 12.

[0091] In one embodiment, the ratio of the first luminous intensity E1 to the second luminous intensity E2 is further defined to be greater than or equal to 20, for example, E1 / E2 is 30, 50, 100, etc., which can improve the self-isolation effect between each pixel, reduce the crosstalk between each pixel, and improve the yield and display effect of the LED display device.

[0092] In one embodiment, the shortest distance between the edge of each pixel electrode 141 and the edge of other adjacent pixel electrodes 141 is less than or equal to 10 μm, such as 10 μm, 8 μm, 6 μm, 4 μm, 2 μm, etc., which can meet the pixel density requirements of LED display devices without the need for isolation through etching processes.

[0093] Of course, the relationship between the first luminous intensity E1 and the second luminous intensity E2 can also be set to... Figure 8 On the LED display device shown, isolation between each pixel is achieved to avoid the negative impact of etching damage, improve the reliability and yield of the LED display device, and reduce the probability of leakage. This will not be elaborated further here.

[0094] It is understood that the LED display device in this embodiment also includes the aforementioned driving backplate 200, which is used to provide driving signals to the corresponding pixel through the pixel electrode 141. For details, please refer to the above embodiment, which will not be repeated here.

[0095] The above description is merely an embodiment of this application and does not limit the patent scope of this application. Any equivalent structural or procedural transformations made using the content of this application's specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of this application.

Claims

1. An LED display device, characterized in that, The LED display device includes a light-emitting epitaxial wafer, the light-emitting epitaxial wafer comprising: Active layer; The first current diffusion layer and the second current diffusion layer are respectively disposed on opposite sides of the active layer; A first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on the side of the first current diffusion layer away from the active layer, and the second electrode layer is disposed on the side of the second current diffusion layer away from the active layer, and the first electrode layer includes a plurality of pixel electrodes arranged in an array. The thickness and resistivity of the first current diffusion layer are set such that, when the LED display device is operating normally, the lateral current diffusion length of the first current diffusion layer satisfies... Where Ls is the lateral current diffusion length of the first current diffusion layer, and D1 is the shortest distance between the edges of adjacent pixel electrodes, the lateral current diffusion length Ls of the first current diffusion layer is calculated by the following formula: Where k is the Boltzmann constant, T is the thermodynamic temperature, e is the electron charge, and t is the thickness of the first current diffusion layer. The resistivity of the first current diffusion layer. The current density within the first current diffusion layer covering the pixel electrode when the LED display device is operating normally.

2. The LED display device according to claim 1, characterized in that, The resistivity of the first current diffusion layer is greater than or equal to 0.1 Ω·cm.

3. The LED display device according to claim 2, characterized in that, The thickness of the first current diffusion layer is less than or equal to 1 μm.

4. The LED display device of claim 3, wherein, The resistivity of the first current diffusion layer is greater than or equal to 0.5 Ω·cm, and the thickness of the first current diffusion layer is less than or equal to 0.5 μm.

5. The LED display device of claim 3, wherein, The resistivity of the first current diffusion layer is greater than or equal to 1 Ω·cm, and the thickness of the first current diffusion layer is less than or equal to 0.1 μm.

6. The LED display device of claim 1, wherein, 。 7. The LED display device of claim 1, wherein, 。 8. The LED display device of claim 1, wherein, where D2 is the spacing between the geometric centers of the pixel electrodes disposed adjacent to one another.

9. The LED display device of claim 1, wherein, The LED display device further includes a driving backplane, which includes a backplane body and a plurality of switching devices arranged in an array on the backplane body, wherein each pixel electrode is electrically connected to the corresponding switching device so that the connected switching device provides a driving signal.

10. The LED display device of claim 9, wherein, The driving backplate is bonded and fixed to the light-emitting epitaxial sheet; The pixel electrode is formed on the backplate body and forms a conductive contact with the first current diffusion layer when the driving backplate is bonded and fixed to the light-emitting epitaxial wafer. or, The pixel electrode is formed on the first current diffusion layer, and the driving backplane further includes a plurality of bonding electrodes arranged in an array on the backplane body. Each bonding electrode is electrically connected to the corresponding switching device and is aligned and bonded to the corresponding pixel electrode.

11. The LED display device of claim 9, wherein, The driving backplate is formed on one side of the light-emitting epitaxial wafer by growth. The pixel electrode is formed on the first current diffusion layer. When the driving backplate is formed by growth, the switching device is grown and formed corresponding to the position of the pixel electrode. The LED display device further includes a backplate substrate located on the side of the backplate body away from the pixel electrode, and bonded and fixed to the backplate body.

12. The LED display device of claim 1, wherein, One of the first current diffusion layer and the second current diffusion layer is an N-type semiconductor layer and the other is a P-type semiconductor layer, and the second electrode layer is a common electrode layer.

13. An LED display device, characterized by, The LED display device includes a light-emitting epitaxial wafer, the light-emitting epitaxial wafer comprising: Active layer; The first current diffusion layer and the second current diffusion layer are respectively disposed on opposite sides of the active layer; A first electrode layer and a second electrode layer, wherein the first electrode layer is disposed on the side of the first current diffusion layer away from the active layer, and the second electrode layer is disposed on the side of the second current diffusion layer away from the active layer, and the first electrode layer includes a plurality of pixel electrodes arranged in an array. The thickness and resistivity of the first current diffusion layer are set such that when a normal operating voltage is applied to each pixel electrode and the second electrode layer respectively, the light generated in the area covered by each pixel electrode has a first luminous intensity, and the light generated in the area covered by the lateral diffusion current generated by each pixel electrode in the adjacent pixel electrode has a second luminous intensity, and the ratio of the first luminous intensity to the second luminous intensity is greater than or equal to 10.

14. The LED display device of claim 13, wherein, The thickness of the first current diffusion layer is less than or equal to 1 μm, and the resistivity of the first current diffusion layer is greater than or equal to 0.1 Ω·cm.

15. The LED display device according to claim 13, characterized in that, The ratio of the first luminous intensity to the second luminous intensity is greater than or equal to 20.

16. The LED display device of claim 13, wherein, The shortest distance between each pixel electrode and the edge of the other pixel electrode disposed adjacently is less than or equal to .

Images