LED display substrate and LED display equipment

Abstract

The invention discloses an LED display substrate and an LED display device.The LED display substrate comprises a light-emitting epitaxial layer, a first dielectric cladding, a reflecting layer and a plurality of reflecting electrodes, the light-emitting epitaxial layer comprises a first semiconductor layer, an active layer and a second semiconductor layer, and the first semiconductor layer forms a first main concave area and a plurality of first boss structures; the first dielectric cladding is arranged in the first main concave area and is in contact with the side wall of the first boss structure, and the refractive index of the first dielectric cladding is different from that of the first semiconductor layer; the reflecting layer is arranged on one side, deviating from the active layer, of one of the first semiconductor layer and the second semiconductor layer; the reflecting electrode is arranged on the side, away from the active layer, of the other one of the first semiconductor layer and the second semiconductor layer, and the reflectivity of the reflecting layer is smaller than that of the reflecting electrode, so that a resonant cavity emitting light from one side of the reflecting layer is formed. By means of the method, light emitted by the LED display substrate can be more collimated, and the light emitting efficiency of the LED display substrate can be improved.

Description

Technical Field

[0001] The present application relates to the technical field of semiconductor light emitting diodes, and in particular to an LED display substrate and an LED display device. Background Art

[0002] LEDs (Light Emitting Diodes) are semiconductor components that convert electrical energy into visible light. They are widely used as lighting sources in modern applications such as indicators, displays, decoration, backlighting, general lighting, and urban nightscapes. With the advancement of technology, the light-emitting chips that primarily emit light in LEDs have reached micrometer scale, enabling smaller LED chip sizes. However, as the size of LED chips miniaturized to micrometer scale decreases, the edge light intensity also increases. This resulting size effect affects the collimation of the light and reduces the optical efficiency of the system. Summary of the Invention

[0003] The embodiments of the present application provide an LED display substrate and an LED display device, which can make the light emitted by the LED display more collimated and improve the luminous efficiency of the LED display substrate.

[0004] In a first aspect, an embodiment of the present application provides an LED display substrate, which includes a light-emitting epitaxial layer, a light-emitting epitaxial layer, a reflective layer, and a plurality of reflective electrodes.

[0005] The light-emitting epitaxial layer includes a first semiconductor layer, an active layer and a second semiconductor layer stacked in sequence, wherein the first semiconductor layer forms a first main recessed area on the side away from the active layer and a plurality of first boss structures arranged in an array and separated by the first main recessed area, and the depth of the first main recessed area is less than or equal to the thickness of the first semiconductor layer at the first boss structure.

[0006] The light emitting epitaxial layer is arranged in the first main recessed area and contacts the sidewall of the first boss structure, wherein the refractive index of the first dielectric cladding is different from that of the first semiconductor layer, thereby forming a reflective interface between the sidewall of the first boss structure and the first dielectric cladding.

[0007] The reflective layer is disposed on a side of one of the first semiconductor layer and the second semiconductor layer away from the active layer.

[0008] A plurality of reflective electrodes are arranged in an array at intervals on a side of the other of the first semiconductor layer and the second semiconductor layer facing away from the active layer, and respectively correspond to the plurality of first boss structures, wherein the reflectivity of the reflective layer is lower than the reflectivity of the reflective electrode, so as to form a resonant cavity that emits light from one side of the reflective layer.

[0009] In a second aspect, an embodiment of the present application provides an LED display device, which includes an LED display substrate and a driving substrate as described in the above embodiment, wherein the driving substrate includes a plurality of power supply electrodes arranged in an array and spaced apart from each other, the LED display substrate is fixed on the driving substrate, and the power supply electrodes are conductively connected to corresponding reflective electrodes to form display pixels corresponding to the first protruding structure.

[0010] The beneficial effects of the present application are as follows: Different from the prior art, the present application sets a first main recessed area in the first semiconductor layer of the light-emitting epitaxial layer for generating light to form a plurality of first boss structures, and sets a reflective layer and a plurality of reflective electrodes on both sides of the plurality of first boss structures, so that the plurality of first boss structures can form a plurality of display pixels. The reflectivity of the reflective layer is less than the reflectivity of the reflective electrode, so that the reflective electrode can reflect the light of the light-emitting epitaxial layer to one side of the reflective layer, so that the light-emitting epitaxial layer at the plurality of first boss structures can form a resonant cavity that emits light from one side of the reflective layer, thereby improving the collimation of the light emitted by the LED display substrate and improving the luminous efficiency. In addition, the present application also sets a first dielectric cladding in the first main recessed area and sets the first dielectric cladding to contact the side wall of the first boss structure, and sets the refractive index of the first dielectric cladding to be different from the refractive index of the first semiconductor layer, so as to be able to form a reflective interface on the side wall of the first boss structure. When the display pixel corresponding to the first boss structure emits light, the first dielectric cladding can reflect the light generated in the first boss structure at the side wall of the first boss structure to reflect the light back into the resonant cavity. The reflective electrode with a higher reflectivity then reflects the light to the side of the reflective layer to reduce light leakage from the side wall of the first boss structure, thereby further improving the collimation of light emitted by the LED display substrate and improving the luminous efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0011] Figure 1 This is a structural diagram of an embodiment of an LED display device of the present application;

[0012] Figure 2 This is a structural diagram of another embodiment of the LED display device of the present application;

[0013] Figure 3 This is a structural diagram of another embodiment of the LED display device of the present application;

[0014] Figure 4 This is a structural diagram of another embodiment of the LED display device of the present application;

[0015] Figure 5 This is a schematic diagram comparing the light emission effects of two implementations of the LED display device embodiment of the present application. DETAILED DESCRIPTION

[0016] The following will be combined with the drawings in the embodiments of this application to clearly and completely describe the technical solutions in the embodiments of this application. Obviously, the embodiments described are only part of the embodiments of this application, not all of the embodiments. Based on the embodiments in this application, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of this application.

[0017] The inventors of this application have discovered through research that LED (Light Emitting Diode) is a semiconductor component that can convert electrical energy into visible light. It is a modern lighting source widely used in the fields of indication, display, decoration, backlight, general lighting and urban night scenes. With the development of science and technology, the main light-emitting chip in LED has been realized in the micron level, making the LED light-emitting chip have a smaller size. However, as the size of the LED light-emitting chip is reduced to the micron level, the edge light intensity also increases. Therefore, the size effect will affect the collimation of the light and reduce the optical efficiency of the system. In order to solve the above problems, this application proposes the following embodiments.

[0018] The following LED display device embodiments of the present application provide an exemplary description of the LED display device.

[0019] The LED display device 10 is a device that generates light by forming multiple display pixels internally. The generated light can be emitted from one side of the LED display device 10 to illuminate or display various information such as text and images. For example, the LED display device 10 can be an LED display chip, an LED digital car light chip, a digital light strip chip, or the like.

[0020] like Figures 1 to 2 As shown, the LED display device 10 may include an LED display substrate 100 and a driving substrate 200. The driving substrate 200 is used to provide power to the LED display substrate 100, and the LED display substrate 100 is used to receive power from the driving substrate 200 so as to form a plurality of display pixels inside to generate light.

[0021] In some embodiments, as Figures 1 to 2 As shown, the LED display substrate 100 may include a light-emitting epitaxial layer 110 , a first dielectric cladding layer 120 , a reflective layer 130 and a plurality of reflective electrodes 140 .

[0022] The light-emitting epitaxial layer 110 can emit light by recombination of electrons and holes under the action of a driving voltage, and define a plurality of display pixels.

[0023] Furthermore, if Figures 1 to 2As shown, the light emitting epitaxial layer 110 may include a first semiconductor layer 111 , an active layer 112 , and a second semiconductor layer 113 , which are sequentially stacked.

[0024] Among them, one of the first semiconductor layer 111 and the second semiconductor layer 113 can be an N-type semiconductor layer and the other can be a P-type semiconductor layer. The active layer 112 is a working medium layer. The first semiconductor layer 111 and the second semiconductor layer 113 are respectively located on the two sides of the active layer 112 and are in contact with the active layer 112. The active layer 112 can form a NiP heterostructure together with the first semiconductor layer 111 and the second semiconductor layer 113 on both sides, which can allow electrons and holes to recombine and form a PN junction to form one or more display pixels.

[0025] Optionally, the first semiconductor layer 111 , the active layer 112 and the second semiconductor layer 113 may be formed by doping semiconductor materials such as AlN, AlGaN, GaN, InGaN, AlInGaN, GaAs, GaP, GaInN, GaAsP, AlGaAs, and AlGaInP.

[0026] In which, the first semiconductor layer 111 can form a first main recess area 1111 and a plurality of first boss structures 1112 arranged in an array manner and separated by the first main recess area 1111 on the side away from the active layer 112, and the depth of the first main recess area 1111 can be less than or equal to the thickness of the first semiconductor layer 111 at the first boss structure 1112.

[0027] Optionally, the first semiconductor layer 111 can be etched on a side of the first semiconductor layer 111 facing away from the active layer 112 to form a plurality of first main recessed regions 1111. A plurality of first platform structures 1112 arranged in an array can be further formed between the first main recessed regions 1111. The array of the plurality of first platform structures 1112 can be consistent with the array of the desired plurality of display pixels, so that the plurality of first platform structures 1112 can define a plurality of display pixels.

[0028] The depth of the first main recessed area 1111 can be less than or equal to the thickness of the first semiconductor layer 111 at the first boss structure 1112, so that the first main recessed area 1111 is not easily damaged during etching of the active layer 112, thereby ensuring the luminous intensity of the light-emitting epitaxial layer 110. Figure 1 or Figure 2 As shown, in the thickness direction A of the LED display device 10, the depth of the first main recessed area 1111 is as follows: Figure 1 as well as Figure 2 As shown in the depth C, the thickness of the first semiconductor layer 111 at the first protrusion structure 1112 is as follows Figure 1 as well as Figure 2 Thickness shown as B, where C≤B.

[0029] For example, optionally, the depth of the first main recessed area 1111 can be less than the thickness of the first semiconductor layer 111 at the first boss structure 1112, so that the light-emitting epitaxial layer 110 corresponding to the first main recessed area 1111 also includes the first semiconductor layer 111. When the LED display substrate 100 is powered on and emits light, current can diffuse through the first semiconductor layer 111 corresponding to the first main recessed area 1111 to the first semiconductor layers 111 corresponding to other display pixels.

[0030] Furthermore, if Figures 1 to 2 As shown, the first dielectric cladding 120 can be disposed in the first main recessed region 1111 and contact the sidewalls of the first platform structure 1112. The refractive index of the first dielectric cladding 120 is different from the refractive index of the first semiconductor layer 111, thereby forming a reflective interface between the sidewalls of the first platform structure 1112 and the first dielectric cladding 120.

[0031] The first dielectric cladding 120 may be a cladding material, for example, a dielectric material such as SiO2 or TiO2.

[0032] Specifically, the reflective interface formed by the first dielectric cladding 120 and the sidewall of the first boss structure 1112 can reflect the light inside the first boss structure 1112, so that the light generated by the display pixel corresponding to the first boss structure 1112 is reflected back into the first boss structure 1112 when it propagates to the first dielectric cladding 120.

[0033] In some embodiments, as Figures 1 to 2 As shown, the first dielectric cladding 120 may be disposed to fully surround and contact the sidewalls of the first boss structure 1112 along the circumference of the first boss structure 1112 .

[0034] Such a setting can ensure that the light generated by the display pixel corresponding to the first boss structure 1112 can be reflected back into the first boss structure 1112 to a large extent when it propagates to the side wall of the first boss structure 1112, thereby reducing the leakage of light from the side wall direction of the first boss structure 1112 to reduce light leakage and enhance the luminous efficiency of the LED display substrate 100.

[0035] In some embodiments, the absolute value of the difference between the refractive index of the first dielectric cladding 120 and the refractive index of the first semiconductor layer 111 can be no less than 0.8. Specifically, the first dielectric cladding 120 can be disposed within the first main recessed region 1111 and in contact with the first semiconductor layer 111 within the first platform structure 1112. Setting the absolute value of the difference in refractive index between the first dielectric cladding 120 and the sidewalls of the first platform structure 1112 to be no less than 0.8 can enhance the reflective function of the reflective interface formed by the first dielectric cladding 120 and the sidewalls of the first platform structure 1112, thereby better reflecting light propagating to the sidewalls of the first platform structure 1112 and significantly reducing light leakage.

[0036] For example, the first dielectric cladding layer 120 may be made of silicon oxide, which may have a refractive index of approximately 1.45-1.50, and the first semiconductor layer 111 may be made of gallium nitride, which may have a refractive index of approximately 2.3-2.4. The absolute value of the difference between the refractive index of the first dielectric cladding layer 120 and the refractive index of the first semiconductor layer 111 may be 0.8-0.95.

[0037] In some embodiments, the first dielectric cladding 120 can be formed by deposition. Specifically, during the fabrication of the LED display substrate 100, after the first main recessed region 1111 is etched to form the plurality of first platform structures 1112, the first dielectric cladding 120 can be deposited within the first main recessed region 1111, such that the first dielectric cladding 120 fully surrounds and contacts the sidewalls of the first platform structures 1112 along their circumference. Forming the first dielectric cladding 120 by deposition can simplify the fabrication process of the LED display substrate 100 and reduce the difficulty of fabricating the LED display substrate 100.

[0038] Furthermore, if Figures 1 to 2 As shown, the reflective layer 130 can be disposed on a side of one of the first semiconductor layer 111 and the second semiconductor layer 113 facing away from the active layer 112. A plurality of reflective electrodes 140 are arranged in an array and spaced apart on a side of the other of the first semiconductor layer 111 and the second semiconductor layer 113 facing away from the active layer 112, and correspond to the plurality of first protrusion structures 1112. The reflectivity of the reflective layer 130 is lower than that of the reflective electrodes 140, thereby forming a resonant cavity 11 from which light is emitted from the reflective layer 130.

[0039] The reflective layer 130 and the plurality of reflective electrodes 140 may correspond to the plurality of first protrusion structures 1112. The reflective layer 130 may serve as the N-electrode of the LED display substrate 100, and the reflective electrode 140 may serve as the P-electrode of the LED display substrate 100, so that the display pixels corresponding to the plurality of first protrusion structures 1112 in the LED display substrate 100 can emit light under the action of the reflective layer 130 and the reflective electrode 140.

[0040] In some embodiments, as Figure 1 as well as Figure 2 As shown, the driving substrate 200 may include a plurality of power supply electrodes 210 spaced apart in an array manner, the LED display substrate 100 may be fixed on the driving substrate 200 , and the power supply electrodes 210 are conductively connected to the corresponding reflective electrodes 140 to form display pixels corresponding to the first boss structure 1112 .

[0041] Specifically, the multiple power supply electrodes 210 correspond to the multiple reflective electrodes 140. The driver substrate 200 can conduct a driving current to the reflective electrodes 140 via the power supply electrodes 210. The driving current can then flow through the reflective electrodes 140 to the light-emitting epitaxial layer 110, driving the light-emitting epitaxial layer 110 to achieve light emission. This arrangement enables the LED display device 10 to precisely control individual display pixels through the multiple power supply electrodes 210 and the multiple reflective electrodes 140, thereby enhancing and enriching the display effects of the LED display substrate 100.

[0042] In some embodiments, as Figure 1 as well as Figure 2 As shown, the reflective layer 130 and the reflective electrode 140 may both be a double-layer structure consisting of a conductive layer and a reflective mirror layer. Alternatively, the reflective layer 130 may include a first conductive layer 131 and a first reflective mirror layer 132 stacked sequentially in the thickness direction A, and the reflective electrode 140 may include a second conductive layer 141 and a second reflective mirror layer 142 stacked sequentially in the thickness direction A.

[0043] The first conductive layer 131 may be disposed on a side of one of the first semiconductor layer 111 and the second semiconductor layer 113 facing away from the active layer 112. The second conductive layer 141 may be disposed on a side of the other of the first semiconductor layer 111 and the second semiconductor layer 113 facing away from the active layer 112. The first reflector layer 132 may be disposed on a side of the first conductive layer 131 facing away from the light-emitting epitaxial layer 110, and the second reflector layer 142 may be disposed on a side of the second conductive layer 141 facing away from the light-emitting epitaxial layer 110 and electrically connected to the power supply electrode 210.

[0044] Optionally, the first conductive layer 131 may be a transparent metal layer, such as an ITO layer, or a metal layer formed by doping multiple metal layers of titanium, chromium, etc. with aluminum. The second conductive layer 141 may be an ITO layer, a metal aluminum layer, or a metal layer formed by doping multiple metal layers of titanium, chromium, etc. with aluminum. The first conductive layer 131 and the second conductive layer 141 may respectively form a bonding structure with the light-emitting epitaxial layer 110 to form an ohmic contact, and can serve as the P electrode or N electrode of the light-emitting epitaxial layer 110, thereby enhancing the propagation and diffusion of current when the LED display substrate 100 is powered on to emit light, thereby enhancing the luminous effect of the LED display substrate 100.

[0045] Optionally, the first reflector layer 132 may be a DBR reflector, which is a multi-layer SiO2 / TiO2 dielectric film structure. The second reflector layer 142 may be a DBR reflector, or may be a metal aluminum layer. The reflectivity of the second reflector layer 142 may be greater than that of the first reflector layer 132, so that the reflectivity of the reflective electrode 140 is greater than that of the reflective layer 130, thereby forming a resonant cavity 11 between the first reflector layer 132 and the second reflector layer 142.

[0046] Of course, the reflective layer 130 and the reflective electrode 140 can also be a single-layer structure that can achieve ohmic contact with the light-emitting epitaxial layer 110 and can also reflect light. For example, the reflective electrode 140 can be a metal aluminum layer, and the reflective layer 130 can be a transparent ITO layer.

[0047] In some embodiments, as Figure 1 as well as Figure 2 As shown, the LED display substrate 100 may further include a common electrode layer 150. The common electrode layer 150 may be disposed on a side of the reflective layer 130 facing away from the active layer 112 and electrically connected to the first semiconductor layer 111 through the reflective layer 130. When both the reflector 132 and the first semiconductor layer 131 are made of conductive materials, the common electrode 150 may be directly connected to the reflective layer 130 for power supply. When the reflector 132 is made of an insulating DBR dielectric material, etching is required to remove the reflector 132 above the first main recessed region 1111, allowing the common electrode 150 to be directly connected to the conductive layer 131 for power supply.

[0048] Furthermore, the common electrode layer 150 may be provided with windows 151 corresponding to the plurality of first protrusion structures 1112 , respectively, and the light output from one side of the reflective layer 130 is further output through the windows 151 .

[0049] The common electrode layer 150 can be connected to an external circuit to provide a reference voltage to the light-emitting epitaxial layer 110 , so that the light-emitting epitaxial layer 110 emits light under the combined action of the driving substrate 200 and the common electrode layer 150 .

[0050] Optionally, the common electrode layer 150 can serve as a common N electrode of the LED display electrode, capable of transmitting voltage and current to the first semiconductor layer 111, so that the current can diffuse to multiple display pixels corresponding to multiple first boss structures 1112, thereby enabling the light-emitting epitaxial layer 110 at the display pixels to smoothly emit light.

[0051] In some embodiments, the common electrode layer 150 can form a bonded metal structure with the reflective layer 130, so that the common electrode layer 150 can form an ohmic contact with the first semiconductor layer 111 through the reflective layer 130, thereby better providing current and voltage to the light-emitting epitaxial layer 110. Optionally, the common electrode layer 150 can be formed of a conductive material such as Cr, Ti, Ni metal, or Au metal.

[0052] Based on the above description, the specific structure of the LED display substrate 100 may include the following three different implementations:

[0053] The first implementation method:

[0054] like Figure 1 As shown, the reflective layer 130 is disposed on a side of the first semiconductor layer 111 away from the active layer 112 , and a plurality of reflective electrodes 140 are arranged in an array and spaced apart on a side of the second semiconductor layer 113 away from the active layer 112 .

[0055] The first semiconductor layer 111 is an N-type semiconductor layer, and the second semiconductor layer 113 can be a P-type semiconductor layer. This means that when the light-emitting epitaxial layer 110 emits light through recombination, electrons in the first semiconductor layer 111 combine with holes in the second semiconductor layer 113 to generate light. Because the reflectivity of the reflective layer 130 is lower than that of the reflective electrode 140, when the light-emitting epitaxial layer 110 emits light through recombination, the light is reflected by the reflective electrode 140 (with a higher reflectivity) toward the reflective layer 130. This allows the LED display substrate 100 to emit light from the side of the first semiconductor layer 111 facing away from the active layer 112.

[0056] Furthermore, a first main recessed region 1111 and a plurality of first platform structures 1112 are formed in the first semiconductor layer 111, a reflective layer 130 is disposed on the side of the plurality of first platform structures 1112 facing away from the active layer 112, and a reflective electrode 140 is disposed on the side of the second semiconductor layer 113 facing away from the active layer 112. This allows the light-emitting epitaxial layer 110 corresponding to the plurality of first platform structures 1112 to form a resonant cavity 11, and can form display pixels that emit light from one side of the first platform structures 1112. The depth of the first main recessed region 1111 can be less than or equal to the thickness of the first semiconductor layer 111 at the first platform structures 1112.

[0057] Furthermore, the first dielectric cladding 120 may wrap a plurality of first protrusion structures 1112 in the first main recessed region 1111 in the first semiconductor layer 111 and facing the sidewalls of the first main recessed region 1111 to form a reflective interface on the sidewalls of the first main recessed region 1111 .

[0058] This arrangement allows the LED display substrate 100 to emit light when powered on. Light in the light-emitting epitaxial layer 110 is reflected by the reflective electrode 140 and conducted to the side of the first semiconductor layer 111. When it reaches the sidewall of the first platform structure 1112, it is reflected back into the first platform structure 1112 by the reflective interface formed by the first dielectric cladding 120. This allows the majority of light generated in the light-emitting epitaxial layer 110 to be concentrated and reflected by the reflective electrode 140 to the side of the reflective layer 130 for light emission, thereby improving the light emission collimation of the LED display substrate 100. Furthermore, by arranging the first platform structure 1112 on the light-emitting side, the reflective interface formed by the first dielectric cladding 120 is also formed on the light-emitting side of the light-emitting epitaxial layer 110, thereby further preventing optical crosstalk between display pixels of the LED display substrate 100 and further improving the luminous efficiency of the LED display substrate 100.

[0059] Optionally, ion bombardment can be performed on the second semiconductor layer 113 and the active layer 112 corresponding to the regions between the multiple reflective electrodes 140 to form insulating regions (not shown). This achieves electrical insulation between the second semiconductor layer 113 and the active layer 112 corresponding to the multiple reflective electrodes 140. This configuration can prevent the driving currents of the multiple display pixels in the light-emitting epitaxial layer 110 from interfering with each other, thereby reducing electrical crosstalk between the multiple display pixels.

[0060] Alternatively, as Figure 1 As shown, the common electrode layer 150 can be disposed on the side of the reflective layer 130 facing away from the first semiconductor layer. When the reflective layer 130 is made of a conductive material, the common electrode layer 150 can be electrically connected to the reflective layer 130. Furthermore, the common electrode layer 150 is provided with windows 151 corresponding to the plurality of first boss structures 1112. Light output from one side of the reflective layer 130 is further output through the windows 151. When the LED display substrate 100 is powered on, the common electrode layer 150 can transfer current to the reflective layer 130, which then transfers the current through the reflective layer 130 to the first semiconductor layer 111 at the first boss structures 1112.

[0061] Alternatively, in other embodiments, Figure 3 As shown, the reflective layer 130 can be disposed on a side of the first semiconductor layer 111 away from the active layer 112. The LED display substrate 100 can further include a common electrode layer 150, which can be embedded in the first dielectric cladding layer 120 in the first main recessed area 1111 and conductively connected to the first semiconductor layer 111.

[0062] Specifically, during the preparation of the LED display substrate 100, after the first main recessed area 1111 is etched to form the first protruding platform structure 1112, a first dielectric cladding layer 120 may be firstly provided in the first main recessed area 1111. Figure 3 As shown, the first dielectric cladding 120 can cover the sidewalls of the first boss structure 1112 and the first semiconductor layer 111 at the bottom of the first main recessed area 1111, so that the first dielectric cladding 120 can completely cover the first semiconductor layer 111 in the first main recessed area 1111 and can reflect the leakage light emitted from the sidewalls of the first boss structure 1112.

[0063] Furthermore, the common electrode layer 150 is continuously deposited in the first main recessed area 1111 , so that the common electrode layer 150 can be embedded in the first dielectric cladding layer 120 in the first main recessed area 1111 , and the side of the common electrode layer 150 facing away from the first dielectric cladding layer 120 is exposed.

[0064] Optionally, after the common electrode layer 150 is added, the side of the first platform structure 1112 facing away from the epitaxial layer 110 can be polished to make the side of the first platform structure 1112 facing away from the epitaxial layer 110 more flat. A reflective layer 130 can then be added to the side of the first platform structure 1112 facing away from the epitaxial layer 110. The common electrode layer 150 can form an ohmic contact with the first conductive layer 131 of the reflective layer 130, and the first conductive layer 131 of the reflective layer 130 can also form an ohmic contact with the first semiconductor layer 111 at the first platform structure 1112. For example, the common electrode layer 150 can be a Cu layer, and the first conductive layer 131 can be an ITO layer. The common electrode layer 150 and the first conductive layer 131 can be electrically connected.

[0065] Specifically, when the common electrode layer 150 is powered on, the common electrode layer 150 and the first conductive layer 131 in the reflective layer 130 can serve as N electrodes of the epitaxial layer 110 , and the common electrode layer 150 can provide current to the first semiconductor layer 111 through the reflective layer 130 .

[0066] The common electrode layer 150 is arranged in the first main recessed area 1111 and embedded in the first dielectric cladding 120. This not only makes the reflective layer 130 smoother and allows light to be more collimated when passing through the reflective layer 130, but also reduces the size occupied by the common electrode layer 150 in the thickness direction of the LED display substrate 100, thereby making the LED display substrate 100 thinner.

[0067] Second implementation method:

[0068] like Figure 2As shown, the reflective layer 130 can be disposed on a side of the second semiconductor layer 113 away from the active layer 112 , and a plurality of reflective electrodes 140 can be arranged in an array and spaced apart on a side of the first semiconductor layer 111 away from the active layer 112 .

[0069] The second semiconductor layer 113 is an N-type semiconductor layer, and the first semiconductor layer 111 can be a P-type semiconductor layer. This means that when the light-emitting epitaxial layer 110 emits light through recombination, electrons in the second semiconductor layer 113 combine with holes in the first semiconductor layer 111 to generate light. Because the reflectivity of the reflective layer 130 is lower than that of the reflective electrode 140, when the light-emitting epitaxial layer 110 emits light through recombination, the light is reflected by the reflective electrode 140, which has a higher reflectivity, toward the reflective layer 130. This allows light to escape from the side of the second semiconductor layer 113 facing away from the active layer 112.

[0070] Furthermore, a first main recessed region 1111 and a plurality of first protruding terrace structures 1112 are formed in the first semiconductor layer 111. A reflective electrode 140 is disposed on the side of the plurality of first protruding terrace structures 1112 facing away from the active layer 112. The reflective layer 130 is separated from the plurality of first protruding terrace structures 1112 by the active layer 112 and the second semiconductor layer 113, and is disposed on the side of the second semiconductor layer 113 facing away from the active layer 112. This allows the light-emitting epitaxial layer 110 corresponding to the plurality of first protruding terrace structures 1112 to form a resonant cavity 11, and enables the LED display substrate 100 to form display pixels that emit light from the side of the second semiconductor layer 113.

[0071] The first dielectric cladding 120 wraps a plurality of first protrusion structures 1112 in the first main recessed region 1111 in the first semiconductor layer 111 and faces the sidewalls of the first main recessed region 1111 to form a reflective interface on the sidewalls of the first main recessed region 1111 .

[0072] This arrangement not only allows the reflective interface formed by the first dielectric cladding 120 to reflect the light corresponding to the first protruding platform structure 1112 together with the reflective electrode 140, so that the light from the LED display substrate 100 can be concentrated on the side of the reflective layer 130, thereby improving the collimation of the emitted light. In addition, by setting the light-emitting surface to be the side of the second semiconductor layer 113 facing away from the active layer 112, the light-emitting side can be made smoother, further improving the collimation of the emitted light, and also facilitating the addition of the reflective layer 130 and other functional components to the light-emitting side of the second semiconductor layer 113 when manufacturing the LED display device 10.

[0073] Optionally, ion bombardment can be performed on the first semiconductor and active layer 112 corresponding to the first main recessed region 1111 to form an insulating region (not shown) to electrically isolate the first semiconductor and active layer 112 corresponding to the plurality of first protrusion structures 1112. This arrangement can prevent the driving currents of the plurality of display pixels in the light-emitting epitaxial layer 110 from affecting each other, thereby reducing electrical crosstalk between the plurality of display pixels.

[0074] Alternatively, as Figure 2 As shown, the common electrode layer 150 is arranged on the side of the reflective layer 130 away from the second semiconductor, and the common electrode layer 150 forms a bonding structure with the reflective layer 130, so as to be able to form an ohmic contact with the reflective layer 130, and can serve as the N electrode of the light-emitting epitaxial layer 110 together with the reflective layer 130, and provide a reference current for the second semiconductor through the reflective layer 130.

[0075] The common electrode layer 150 can be arranged in a grid pattern, with multiple windows 151 corresponding to the multiple first protrusion structures 1112. The windows 151 correspond to the multiple display pixels, so that the common electrode layer 150 does not block light emitted from the multiple display pixels when the light-emitting epitaxial layer 110 emits light. The grid-like common electrode layer 150 can also further define the positions of the display pixels to prevent optical crosstalk between the display pixels.

[0076] The third implementation method:

[0077] On the basis of the first platform structure 1112 of the first semiconductor layer 111, a platform structure can also be provided in the second semiconductor layer 113, so that both the first semiconductor layer 111 and the second semiconductor layer 113 are provided with a platform structure. The specific structure is as follows:

[0078] See Figure 4 The second semiconductor layer 113 may form a second main recessed area 1131 and a plurality of second protrusion structures 1132 arranged in an array and spaced apart by the second main recessed areas 1131 on a side facing away from the active layer 112 .

[0079] The second platform structures 1132 correspond to the first platform structures 1112, so that multiple second platform structures 1132 correspond to multiple display pixels. The depth of the second main recessed area 1131 can be less than or equal to the thickness of the second semiconductor layer 113 at the second platform structures 1132. Therefore, during the process of etching the light-emitting epitaxial layer 110 to form the second main recessed area 1131, the active layer 112 is not easily damaged by etching, thereby ensuring the luminous intensity of the LED display device 10.

[0080] Alternatively, as Figure 4As shown, the LED display substrate 100 may further include a second dielectric cladding 160, which is disposed within the second main recessed region 1131 and contacts the sidewalls of the second boss structure 1132. The refractive index of the second dielectric cladding 160 is different from that of the second semiconductor layer 113, thereby forming a reflective interface between the sidewalls of the second boss structure 1132 and the second dielectric cladding 160. Optionally, the second dielectric cladding 160 may be consistent with the first dielectric cladding 120 and may be made of a dielectric material such as SiO2.

[0081] During the process of light generation by the light-emitting epitaxial layer 110, the light-emitting epitaxial layer 110 in the display pixel generates light. When the light reaches the sidewalls of the second boss structure 1132 and the sidewalls of the first boss structure 1112, the second dielectric cladding 160 and the first dielectric cladding 120 can reflect the light back into the second boss structure 1132 and the first boss structure 1112. As a result, the reflective electrode 140 with a higher reflectivity reflects the light in the light-emitting epitaxial layer 110 to one side of the reflective layer 130, so that the light can exit the cavity from one side of the reflective layer 130.

[0082] A boss structure is provided in both the first semiconductor layer 111 and the second semiconductor layer 113, and a dielectric cladding is provided on the sidewalls of the boss structure. This allows the light within the display pixel to be concentratedly reflected by the reflective electrode 140 when propagating in the light-emitting epitaxial layer 110, thereby further improving the collimation of the light emitted by the LED display substrate 100 and further improving the luminous efficiency of the LED display substrate 100.

[0083] For example, if the second semiconductor layer 113 is a P-electrode, the second protrusion structure 1132 and the second main recessed area 1131 are disposed on a side close to the reflective electrode 140, and the side of the second protrusion structure 1132 facing away from the active layer 112 is conductively connected to the reflective electrode 140. The specific structure of the second semiconductor layer 113 may refer to the structure of the first semiconductor layer 111 in the second embodiment, and will not be further described in this embodiment.

[0084] Alternatively, if the second semiconductor layer 113 is an N-electrode, the second protrusion structure 1132 and the second main recessed area 1131 are disposed on a side close to the reflective layer 130. The side of the second protrusion structure 1132 facing away from the active layer 112 is conductively connected to the reflective electrode 140 and may be connected to the common electrode layer 150. The specific structure of the second semiconductor layer 113 may refer to the structure of the first semiconductor layer 111 in the first embodiment, and will not be further described in this embodiment.

[0085] In some embodiments, the boss structures of the above three embodiments may include multiple sub-boss structures. The following is an exemplary description of the sub-boss structures in the boss structure based on the LED display device 10 shown in the third embodiment:

[0086] like Figure 4 As shown, in some embodiments, a first auxiliary recessed region 1113 may be formed on a side of the first platform structure 1112 facing away from the active layer 112 to separate the first platform structure 1112 into a plurality of first sub-platform structures 1114. The depth of the first auxiliary recessed region 1113 is less than or equal to the thickness of the first semiconductor layer 111 at the first sub-platform structures 1114. A first dielectric cladding layer 120 may be further disposed in the first auxiliary recessed region 1113 and respectively contact sidewalls of the plurality of first sub-platform structures 1114.

[0087] Specifically, when the reflective electrode 140 or the reflective layer 130 covers the side of the first platform structure 1112 facing away from the active layer 112, it also covers the multiple first sub-platform structures 1114 and the first auxiliary recessed region 1113. Furthermore, because the light-emitting epitaxial layer 110 corresponding to the first platform structure 1112 serves as a display pixel, the display pixels corresponding to the multiple first sub-platform structures 1114 can form multiple small resonant cavities 11, thereby further improving the collimation of the emitted light.

[0088] Alternatively, as Figure 4 As shown, the first dielectric cladding layer 120 can be filled in the first auxiliary recessed area 1113 to form a fully surrounding contact with the sidewalls of the plurality of first sub-projection structures 1114, thereby forming a reflective interface on the sidewalls of the plurality of first sub-projection structures 1114. When the display pixel emits light, the reflective electrode 140 reflects the light toward the reflective layer 130. The angle of the light can be further corrected as it propagates through the plurality of first sub-projection structures 1114, thereby making the light emitted from the LED display substrate 100 more collimated.

[0089] In some embodiments, as Figure 4 As shown, a second auxiliary recessed region 1133 may also be formed on the side of the second platform structure 1132 facing away from the active layer 112 to separate the second platform structure 1132 into a plurality of second sub-platform structures 1134. The depth of the second auxiliary recessed region 1133 is less than or equal to the thickness of the second semiconductor layer 113 at the second sub-platform structures 1134. The second dielectric cladding layer 160 is further disposed in the second auxiliary recessed region 1133 and contacts the sidewalls of the plurality of second sub-platform structures 1134.

[0090] The plurality of second sub-platform structures 1134 may correspond to the plurality of first sub-platform structures 1114. The reflective layer 130 and the reflective electrode 140 respectively cover the sides of the first and second projection structures 1112 and 1132 facing away from the active layer 112. Therefore, the plurality of second sub-platform structures 1134 within the first and second projection structures 1112 and 1132 may form a plurality of resonant cavities 11 with the plurality of first sub-platform structures 1114. Thus, when the display pixels corresponding to the first and second projection structures 1112 and 1132 emit light, the plurality of resonant cavities 11 may further improve light collimation.

[0091] Alternatively, as Figure 4 As shown, the second dielectric cladding 160 may be filled in the second auxiliary recessed area 1133 to form a fully surrounding contact with the sidewalls of the plurality of second sub-mesa structures 1134 , thereby forming a reflective interface on the sidewalls of the plurality of second sub-mesa structures 1134 .

[0092] When the light-emitting epitaxial layer 110 corresponding to the display pixel emits light, the light inside the light-emitting epitaxial layer 110 is reflected by the reflective electrode 140, and then the propagation angle can be further corrected multiple times by the reflective interface of the side walls of the multiple first sub-boss structures 1114 and the multiple second sub-boss structures 1134, so that the light can be more collimated and emitted from the side of the reflective layer 130.

[0093] like Figure 5 As shown, Figure 5 The middle curve a is the light emission effect when a display pixel does not have multiple resonant cavities 11. Figure 5 Curve b in the middle shows the light emission effect when a display pixel is provided with multiple resonant cavities 11. Comparing curve a and curve b, it can be seen that the light emitted by the display pixel with multiple resonant cavities 11 is more collimated.

[0094] Such a configuration enables the LED display substrate 100 to achieve collimated light output under the multiple effects of the reflective layer 130, the reflective electrode 140, the reflective interface of the side wall of the first boss structure 1112, the reflective interface of the side wall of the second boss structure 1132, the reflective interface of the side wall of the first sub-boss structure 1114, and the reflective interface of the side wall of the second sub-boss structure 1134, thereby further improving the collimation of the light output of the LED display substrate 100 and improving the luminous efficiency of the LED display substrate 100.

[0095] Moreover, the size of the display pixel can also be adjusted in the lateral direction to ensure that the display image can achieve collimated light emission under the action of the resonant cavity 11 surrounded by the cladding material on multiple sides, while reducing the lateral size of the display pixel, thereby reducing the size of the LED display device 10.

[0096] Of course, in other embodiments, the sub-boss structure may also be disposed in only one of the first boss structure 1112 and the second boss structure 1132 , which will not be specifically listed one by one in this embodiment.

[0097] In some embodiments, as Figures 1 to 4 As shown, the LED display substrate 100 may further include a plurality of first bonding electrodes 170 and a first filling layer 180 , and the driving substrate 200 may further include a substrate body 220 , a plurality of second bonding electrodes 230 and a second filling layer 240 .

[0098] The plurality of first bonding electrodes 170 can be disposed on the side of the plurality of reflective electrodes 140 facing away from the light-emitting epitaxial layer 110, and can correspond one-to-one with and be conductively connected to the plurality of reflective electrodes 140. The first filling layer 180 can cover the side of the reflective electrode 140 facing away from the light-emitting epitaxial layer 110 and the sidewalls of the first bonding electrodes 170, thereby securing the plurality of first bonding electrodes 170 to the plurality of reflective electrodes 140.

[0099] like Figures 1 to 4 As shown, multiple power supply electrodes 210 can be fixed to one side of the substrate body 220. Multiple second bonding electrodes 230 can be disposed on a side of the multiple power supply electrodes 210 facing away from the substrate body 220, corresponding one-to-one with and conductively connected to the multiple power supply electrodes 210. The second filling layer 240 covers the side of the multiple power supply electrodes 210 facing away from the substrate body 220 and the sidewall surface of the first bonding electrode 170, thereby securing the multiple second bonding electrodes 230 to the multiple power supply electrodes 210.

[0100] The multiple first bonding electrodes 170 can correspond one-to-one with the multiple second bonding electrodes 230, and the surfaces of the multiple first bonding electrodes 170 facing away from the reflective electrode 140 are metal-bonded to the surfaces of the multiple second bonding electrodes 230 facing away from the power supply electrode 210, so that the multiple first bonding electrodes 170 are conductively connected to the multiple second bonding electrodes 230. Therefore, the multiple reflective electrodes 140 and the multiple power supply electrodes 210 can be conductively connected to the second bonding electrodes 230 through the corresponding first bonding electrodes 170, and the driving substrate 200 can sequentially provide driving current to the light-emitting epitaxial layer 110 through the power supply electrode 210, the second bonding electrode 230, the first bonding electrode 170, and the reflective electrode 140.

[0101] The second bonding electrode 230 and the first bonding electrode 170 are arranged between the reflective electrode 140 and the power supply electrode 210 to present a bonding structure, which can improve the fixing effect between the reflective electrode 140 and the power supply electrode 210, thereby achieving a higher strength connection and improving the stability of the internal structure of the LED display device 10.

[0102] Optionally, the side of the first filling layer 180 facing away from the light-emitting epitaxial layer 110 may also be bonded to the side of the second filling layer 240 facing away from the substrate body 220 , thereby making the connection between the driving substrate 200 and the LED display substrate 100 more stable.

[0103] Optionally, the first filling layer 180 and the second filling layer 240 may be oxide layers made of silicon dioxide or other insulating materials. The power supply electrode 210, the first bonding electrode 170, and the second bonding electrode 230 may be electrodes made of metallic copper or other conductive materials. The substrate body 220 may be a CMOS (Complementary Metal Oxide Semiconductor) substrate.

[0104] In summary, the present application provides a first main recessed region 1111 in the first semiconductor layer 111 of the light-emitting epitaxial layer 110 for generating light to form a plurality of first boss structures 1112, and provides a reflective layer 130 and a plurality of reflective electrodes 140 on both sides of the plurality of first boss structures 1112, so that the plurality of first boss structures 1112 can form a plurality of display pixels. The reflectivity of the reflective layer 130 is lower than the reflectivity of the reflective electrode 140, so that the reflective electrode 140 can reflect light from the light-emitting epitaxial layer 110 to one side of the reflective layer 130, thereby enabling the light-emitting epitaxial layer 110 at the plurality of first boss structures 1112 to form a resonant cavity 11 that emits light from one side of the reflective layer 130, thereby improving the collimation of light emitted from the LED display substrate 100 and improving the luminous efficiency. The present application also provides a first dielectric cladding 120 within the first main recessed region 1111, contacting the sidewalls of the first platform structure 1112. Furthermore, the refractive index of the first dielectric cladding 120 is different from that of the first semiconductor layer 111, thereby forming a reflective interface on the sidewalls of the first platform structure 1112. When the display pixel corresponding to the first platform structure 1112 emits light, the first dielectric cladding 120 reflects light generated within the first platform structure 1112 from the sidewalls, thereby reflecting the light back into the resonant cavity 11. The reflective electrode 140, which has a higher reflectivity, then reflects the light toward the reflective layer 130, thereby reducing light leakage from the sidewalls of the first platform structure 1112. This further improves the collimation of light emitted from the LED display substrate 100 and enhances the luminous efficiency of the LED display substrate 100.

[0105] The above description is merely an embodiment of the present application and does not limit the patent scope of the present application. Any equivalent structure or equivalent process transformation made using the contents of the present application specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present application.

Claims

1. An LED display substrate, characterized in that: The LED display substrate comprises: a light-emitting epitaxial layer, the light-emitting epitaxial layer comprising a first semiconductor layer, an active layer, and a second semiconductor layer stacked in sequence, wherein the first semiconductor layer forms a first main recessed region on a side facing away from the active layer and a plurality of first platform structures arranged in an array and spaced apart by the first main recessed region, wherein the depth of the first main recessed region is less than or equal to the thickness of the first semiconductor layer at the first platform structures; a first dielectric cladding disposed in the first main recessed region and contacting a sidewall of the first platform structure, wherein a refractive index of the first dielectric cladding is different from a refractive index of the first semiconductor layer, thereby forming a reflective interface between the sidewall of the first platform structure and the first dielectric cladding; a reflective layer, disposed on a side of one of the first semiconductor layer and the second semiconductor layer facing away from the active layer; a plurality of reflective electrodes arranged in an array and spaced apart from each other on a side of the other of the first semiconductor layer and the second semiconductor layer facing away from the active layer, and respectively corresponding to the plurality of first boss structures, wherein the reflectivity of the reflective layer is less than the reflectivity of the reflective electrodes, so as to form a resonant cavity that emits light from one side of the reflective layer.

2. The LED display substrate according to claim 1, characterized in that: An absolute value of a difference between a refractive index of the first dielectric cladding layer and a refractive index of the first semiconductor layer is not less than 0.

8.

3. The LED display substrate according to claim 1, characterized in that: The first dielectric cladding is formed by deposition.

4. The LED display substrate according to claim 1, characterized in that: The first dielectric cladding is arranged to fully surround and contact the sidewall of the first boss structure along a circumference of the first boss structure.

5. The LED display substrate according to claim 1, characterized in that: A first auxiliary recessed region is formed on the side of the first boss structure facing away from the active layer to separate the first boss structure into a plurality of first sub-boss structures. The depth of the first auxiliary recessed region is less than or equal to the thickness of the first semiconductor layer at the first sub-boss structure. The first dielectric cladding is further arranged in the first auxiliary recessed region and contacts the side walls of the plurality of first sub-boss structures respectively.

6. The LED display substrate according to claim 5, characterized in that: The first dielectric cladding is arranged to fully surround and contact the sidewall of the first sub-boss structure along a circumference of the first sub-boss structure.

7. The LED display substrate according to claim 1, characterized in that: The second semiconductor layer forms a second main recessed area on a side away from the active layer and a plurality of second boss structures arranged in an array and separated by the second main recessed area. The second boss structure corresponds to the first boss structure. The depth of the second main recessed area is less than or equal to the thickness of the second semiconductor layer at the second boss structure. The LED display substrate also includes a second dielectric cladding, which is arranged in the second main recessed area and contacts the side wall of the second boss structure. The refractive index of the second dielectric cladding is different from the refractive index of the second semiconductor layer, thereby forming a reflective interface between the side wall of the second boss structure and the second dielectric cladding.

8. The LED display substrate according to claim 7, characterized in that: A second auxiliary recessed region is formed on the side of the second platform structure facing away from the active layer to separate the second platform structure into a plurality of second sub-platform structures. The depth of the second auxiliary recessed region is less than or equal to the thickness of the second semiconductor layer at the second sub-platform structure. The second dielectric cladding is further arranged in the second auxiliary recessed region and contacts the side walls of the plurality of second sub-platform structures respectively.

9. The LED display substrate according to claim 1, characterized in that: The LED display substrate also includes a common electrode layer, which is arranged on the side of the reflective layer away from the active layer and is electrically connected to one of the first semiconductor layer and the second semiconductor layer through the reflective layer. The common electrode layer is provided with windows corresponding to the multiple first boss structures respectively, and the light output from one side of the reflective layer is further output through the windows.

10. The LED display substrate according to claim 1, characterized in that: The reflective layer is arranged on a side of the first semiconductor layer away from the active layer; the LED display substrate further comprises a common electrode layer, which is embedded in the first dielectric cladding in the first main recessed area and is conductively connected to the first semiconductor layer.

11. An LED display device, characterized in that: The LED display device includes an LED display substrate and a driving substrate as described in any one of claims 1 to 10, wherein the driving substrate includes a plurality of power supply electrodes arranged in an array manner, the LED display substrate is fixed on the driving substrate, and the power supply electrodes are conductively connected to corresponding reflective electrodes to form display pixels corresponding to the first boss structure.

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