LED display unit, display module and manufacturing method

Abstract

The invention discloses an LED display unit, a display module and a manufacturing method, the LED display unit comprises a transparent substrate, the substrate is provided with a first surface and a second surface along the x direction, and the first surface is provided with a TFT drive circuit; the Micro LED chip is electrically connected with the TFT driving circuit, and the micro LED chip is electrically connected with the TFT driving circuit; the DBR reflecting layer is in the shape of a hemisphere or a semi-ellipsoid, and the Micro LED chip is covered with the DBR reflecting layer; the planarization layer is arranged on the first surface of the substrate and covers the TFT driving circuit and the DBR reflecting layer, and a first signal via hole connected to the MicroLED chip is formed in the planarization layer. According to the LED display unit, the DBR reflecting layer is used for reflecting light emitted by the MicroLED chip, and the effects of dodging light and improving visual angle color cast can be achieved. The planarization layer is manufactured, the first signal via hole is formed, signals are led out to the surface of the planarization layer to form the signal contact, and compared with a traditional side edge lead structure, side edge joints can be reduced as much as possible when the display units are spliced with one another. The invention relates to the field of LEDs.

Description

Technical Field

[0001] The present application relates to the field of LEDs, and in particular to an LED display unit, a display module, and a manufacturing method. Background Art

[0002] MicroLED technology is a miniaturization of LED technology. It is a high-density, tiny LED array display. Like an LED display, each pixel is addressable and individually illuminated. It can be considered a scaled-down version of an outdoor LED display, reducing the pixel pitch from millimeters to microns. Due to its advantages such as self-luminescence, high brightness, low power consumption, and wide color gamut, it is currently attracting widespread attention and is gradually gaining popularity in the market.

[0003] Glass-based LEDs enable ultra-fine pitch, high-density displays. However, due to the presence of row / column scanning driver chips and drive signal traces at the edges of the display, visible seams can be seen at the joints, impacting viewing quality. Therefore, eliminating visible seams, reducing costs, and simplifying the process have become key design priorities. Furthermore, current LED arrays suffer from uneven brightness across individual LEDs, which can also affect the final display quality.

[0004] Currently, most manufacturers use a full-surface TFT driver backplane paired with thousands of MicroLED chips arranged in a matrix to achieve AM-driven ultra-fine pitch, high-density displays. They achieve seamless splicing of MicroLED display modules through side wiring and TGV via double-sided processes. However, this method suffers from inconsistent electrical properties of TFT devices, high process difficulty and low yield, and high resistivity and high voltage drop across the glass substrate, making it impossible to achieve large-scale mass production. Summary of the Invention

[0005] The present application aims to solve at least one of the technical problems existing in the prior art. To this end, the present application proposes an LED display unit with smaller seams and more uniform luminous brightness.

[0006] The present application also proposes a display module including the above-mentioned LED display unit, and a manufacturing method for the above-mentioned LED display unit.

[0007] According to the first embodiment of the present application, the LED display unit includes:

[0008] A substrate, which is a transparent member, is provided with a first surface and a second surface along the x-direction, and the first surface is provided with a TFT driving circuit;

[0009] A MicroLED chip electrically connected to the TFT driving circuit, wherein the MicroLED chip is embedded on the first surface of the substrate;

[0010] A DBR reflective layer, which is hemispherical or hemispherical, and covers the MicroLED chip;

[0011] a planarization layer disposed on the first surface of the substrate and covering the TFT driving circuit and the DBR reflective layer, wherein a first signal via connected to the MicroLED chip is defined in the planarization layer, and the first signal via is defined along the x-direction;

[0012] The light emitted by the MicroLED chip can be reflected by the inner wall of the DBR reflective layer, and the light sequentially passes through the first surface and the second surface of the substrate and propagates to the outside.

[0013] The LED display unit according to the embodiments of the present application has at least the following beneficial effects: The DBR reflective layer reflects light emitted by the MicroLED chip, achieving uniform light and improving visual color deviation. A planarization layer is fabricated and a first signal via is formed to route the signal to the surface of the planarization layer to form a signal contact. Compared to traditional side lead structures, this minimizes side seams when the display units are spliced ​​together.

[0014] According to some embodiments of the present application, a signal electrode is further embedded in the first surface of the substrate, and a second signal via connected to the signal electrode is opened in the planarization layer.

[0015] According to some embodiments of the present application, the materials used to prepare the signal electrode include but are not limited to Ti, Cu, Mo, Ta, Au, Pt, Pd and ITO conductive films and alloy films with Ti, Cu, Mo, Ta, Au, Pt, Pd or ITO as the main body.

[0016] According to some embodiments of the present application, the material of the substrate includes but is not limited to glass, ceramic and polyimide.

[0017] According to some embodiments of the present application, the thickness of the MicroLED chip is 10 to 200 μm.

[0018] According to some embodiments of the present application, materials of the DBR reflective layer and the planarization layer include but are not limited to polyimide, epoxy resin and acrylic.

[0019] According to some embodiments of the present application, the DBR reflective layer is covered with a metal reflective layer.

[0020] According to some embodiments of the present application, the material of the metal reflective layer is ITO / Ag.

[0021] According to the display module of the second embodiment of the present application, it includes a driving backplane and a plurality of the above-mentioned LED display units, each of the LED display units is spliced ​​together and installed on the driving backplane, and the driving backplane drives each of the LED display units to emit light.

[0022] According to the third aspect of the present application, a method for manufacturing the LED display unit includes the following steps:

[0023] fabricating the TFT driving circuit on the substrate;

[0024] Mounting the MicroLED chip on the substrate;

[0025] Fabricating the DBR reflective layer on the substrate, and evaporating a metal reflective layer on the DBR reflective layer;

[0026] Forming the planarization layer on the substrate to cover the MicroLED chip and the DBR reflective layer, and opening the first signal via in the planarization layer;

[0027] Physical vapor deposition technology is used to sputter metal copper on the first signal via to form a seed layer on the inner wall of the first signal via. The seed layer can be a single-layer film composed of copper or copper alloy, or a stacked structure of Ni / Cu, Mo / Cu, or Ti / Cu. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the technical solutions disclosed in this application and constitute a part of the specification. Together with the embodiments disclosed in this application, they are used to explain the technical solutions disclosed in this application and do not constitute a limitation on the technical solutions disclosed in this application.

[0029] Figure 1 A cross-sectional view of a MicroLED display unit currently manufactured using the side-lead process.

[0030] Figure 2 A cross-sectional view of a MicroLED display unit currently manufactured using the TGV via-hole double-sided process.

[0031] Figure 3 This is a cross-sectional view of an LED display unit according to an embodiment of the first aspect of the present application;

[0032] Figure 4 This is a top view of the LED display unit according to the first embodiment of the present application;

[0033] Figure 5 A cross-sectional view of a display module according to an embodiment of the second aspect of the present application;

[0034] Figure 6This is a top view of a driving backplane in a display module according to an embodiment of the second aspect of the present application;

[0035] Figure 7 This is a schematic diagram of preparing a TFT driving circuit on a substrate in the manufacturing method of an embodiment of the third aspect of the present application;

[0036] Figure 8 This is a schematic diagram of installing a MicroLED chip in the manufacturing method of the third embodiment of the present application;

[0037] Figure 9 This is a schematic diagram of installing a DBR reflective layer in the manufacturing method of an embodiment of the third aspect of the present application;

[0038] Figure 10 This is a schematic diagram of preparing a planarization layer in the manufacturing method of the third embodiment of the present application.

[0039] Figure 1: LED light-emitting chip, 2: TFT layer, 3: glass substrate, 4: upper surface metal lead, 5: side metal lead, 6: lower surface metal lead, 7: driver IC, 8: through hole, 100: substrate, 200: TFT driver circuit, 300: MicroLED chip, 400: DBR reflective layer, 500: planarization layer, 510: first signal via, 520: second signal via, 600: signal electrode, 700: driver backplane. DETAILED DESCRIPTION

[0040] The following describes in detail embodiments of the present application. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present application and are not to be construed as limiting the present application.

[0041] In the description of this application, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on this application.

[0042] In the description of this application, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of "first" and "second" in the description is solely for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0043] In the description of this application, unless otherwise clearly defined, terms such as setting, installing, and connecting should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in this application based on the specific content of the technical solution.

[0044] In the description of this application, reference to the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of this application. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any appropriate manner in any one or more embodiments or examples.

[0045] MicroLED technology is a miniaturization of LED technology. It is a high-density, tiny LED array display. Like an LED display, each pixel is addressable and individually illuminated. It can be considered a scaled-down version of an outdoor LED display, reducing the pixel pitch from millimeters to microns. Due to its advantages such as self-luminescence, high brightness, low power consumption, and wide color gamut, it is currently attracting widespread attention and is gradually gaining popularity in the market.

[0046] Glass-based LEDs enable ultra-fine pitch, high-density displays. However, due to the presence of row / column scanning driver chips and drive signal traces at the edges of the display, visible seams can be seen at the joints, impacting viewing quality. Therefore, eliminating visible seams, reducing costs, and simplifying the process have become key design priorities. Furthermore, current LED arrays suffer from uneven brightness across individual LEDs, which can also affect the final display quality.

[0047] Currently, most manufacturers use a full-surface TFT driver backplane with tens of thousands of MicroLED chips arranged in a matrix to realize AM-driven ultra-fine pitch high-density display screens, and use side lead technology and TGV via double-sided technology to achieve seamless splicing of MicroLED display modules. Figure 1 The MicroLED display unit currently adopts the side lead process, in which the LED light-emitting chip 1 and the TFT layer 2 are both arranged on the glass substrate 3, and the TFT layer is electrically connected to the driver IC 7 through the upper surface metal lead 4, the side metal lead 5 and the lower surface metal lead 6 arranged on the surface of the glass substrate, so that the lead bypasses the side of the glass substrate 3. Figure 2MicroLED display units currently utilize a double-sided TGV via process, which provides a through-hole 8 on the glass substrate 3, allowing the TFT layer 2 to establish an electrical connection with the driver IC 7 through the through-hole 8. However, the electrical properties of the TFT devices produced using these two methods are inconsistent. Furthermore, the side wiring process and the double-sided TGV via process are both difficult to manufacture and have low yields. The high resistivity and high voltage drop across the glass substrate also prevent large-scale mass production.

[0048] To address this issue, this application proposes an LED display unit that utilizes a DBR reflective layer to reflect light emitted by a MicroLED chip, achieving uniform light distribution and improving visual color deviation. A planarization layer is fabricated and a first signal via is formed, leading the signal to the surface of the planarization layer to form a signal contact. Compared to traditional side lead structures, this minimizes side seams when display units are spliced ​​together.

[0049] In addition, the present application also proposes a display module including the above-mentioned LED display unit, and a manufacturing method for producing the above-mentioned LED display unit.

[0050] Reference Figure 3 The LED display unit in the embodiment of the first aspect of the present application includes a substrate 100, a TFT driving circuit 200, a MicroLED chip 300, a DBR reflective layer 400, and a planarization layer 500. The substrate 100 is the main structure of the LED display unit and is a transparent member for transmitting light. The substrate 100 has a first surface and a second surface along the x-direction, and the TFT driving circuit 200 is disposed on the first surface.

[0051] The MicroLED chip 300 is electrically connected to the TFT driving circuit 200 and is embedded on the first surface of the substrate 100. The MicroLED chip 300 is capable of emitting light, and the TFT driving circuit 200 is used to drive and control the MicroLED chip 300.

[0052] The DBR reflective layer 400 is hemispherical or hemispherical and covers the MicroLED chip 300 . The inner wall of the DBR reflective layer 400 is covered with a light-reflecting coating, thereby reflecting the light emitted by the MicroLED chip 300 toward the substrate 100 .

[0053] The planarization layer 500 is disposed on the first surface of the substrate 100 and covers the TFT driver circuit 200 and the DBR reflective layer 400. A first signal via 510 connected to the MicroLED chip 300 is defined within the planarization layer 500. The first signal via 510 extends along the x-direction. The planarization layer 500 protects the TFT driver circuit 200 and the DBR reflective layer 400 while also filling any grooves on the device surface to create a smooth surface, facilitating subsequent assembly.

[0054] The light emitted by the MicroLED chip 300 can be reflected by the inner wall of the DBR reflective layer 400 , and the light sequentially passes through the first surface and the second surface of the substrate 100 and propagates to the outside.

[0055] Furthermore, a signal electrode 600 is embedded on the first surface of the substrate 100 , and a second signal via 520 connected to the signal electrode 600 is opened in the planarization layer 500 .

[0056] Furthermore, the materials used to make the signal electrode 600 include, but are not limited to, Ti, Cu, Mo, Ta, Au, Pt, Pd, and ITO conductive films, as well as alloy films primarily composed of Ti, Cu, Mo, Ta, Au, Pt, Pd, or ITO. Coating methods include, but are not limited to, electroplating, chemical plating, magnetron sputtering, and evaporation.

[0057] Furthermore, the material of the substrate 100 includes but is not limited to glass, ceramic and polyimide.

[0058] Furthermore, the thickness of the MicroLED chip 300 is 10 to 200 μm, and it can adopt a substrate-free structure or a substrate-attached structure.

[0059] Furthermore, the materials of the DBR reflective layer 400 and the planarization layer 500 include, but are not limited to, polyimide, epoxy resin, and acrylic. To enhance the reflective effect of the DBR reflective layer 400, a metal reflective layer with a thickness of 10 to 200 μm is applied to the DBR reflective layer 400. Specifically, the metal reflective layer is made of ITO / Ag and has a thickness of 10 to 100 nm.

[0060] Reference Figure 4 , V in the figure DD The contact is the positive electrode for R / G / B sub-pixel power supply, V ss The contact is the negative electrode of the R / G / B sub-pixel power supply, V scan The contact is the scanning signal electrode, V data_R 、V data_GThe data_B contact is the R / G / B sub-pixel data signal electrode. The above are only the signal contacts based on the 2T1C pixel circuit. If the TFT driving circuit 200 is a multi-T multi-C structure, the number and name of the signal contacts can be increased.

[0061] The display module in the second embodiment of the present application, referring to Figure 5 , which includes a driving backplane 700 and a plurality of the above-mentioned LED display units. Each LED display unit is spliced ​​together and mounted on the driving backplane 700. The driving backplane 700 drives each LED display unit to emit light, thereby forming a display module for image display.

[0062] Reference Figure 6 The LED display units on the driving backplane 700 are arranged in an array, and the driving backplane 700 can be made of glass or PCB substrate.

[0063] The manufacturing method for the above-mentioned LED display unit in the embodiment of the third aspect of the present application includes the following steps:

[0064] S100.Reference Figure 7 , a TFT driving circuit 200 is fabricated on the substrate 100 , and in some embodiments, a signal electrode 600 is provided, which is also fabricated simultaneously;

[0065] S200.Reference Figure 8 , mounting a MicroLED chip 300 on the substrate 100;

[0066] S300.Reference Figure 9 , forming a DBR reflective layer 400 on the substrate 100, and evaporating a metal reflective layer on the DBR reflective layer 400 to reflect the light emitted by the MicroLED chip 300;

[0067] S400.Reference Figure 10 A planarization layer 500 is formed on the substrate 100 to cover the MicroLED chip 300 and the DBR reflective layer 400. A first signal via 510 is formed in the planarization layer 500. In some embodiments, a second signal via 520 is also formed and connected to the signal electrode 600.

[0068] S500. Use physical vapor deposition technology to sputter metal copper on the first signal via 510 to form a seed layer on the inner wall of the first signal via 510. The seed layer can be a single-layer film composed of copper or a copper alloy, or a stacked structure of Ni / Cu, Mo / Cu, or Ti / Cu, with a thickness of 50nm to 500nm.

[0069] The embodiments of the present application have been described in detail above with reference to the accompanying drawings. However, the present application is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by ordinary technicians in the relevant technical field without departing from the purpose of the present application. In addition, the embodiments of the present application and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. An LED display unit, characterized in that: include: A substrate, which is a transparent member, is provided with a first surface and a second surface along the x-direction, and the first surface is provided with a TFT driving circuit; A MicroLED chip electrically connected to the TFT driving circuit, wherein the MicroLED chip is embedded on the first surface of the substrate; A DBR reflective layer, which is hemispherical or hemispherical, and covers the MicroLED chip; a planarization layer disposed on the first surface of the substrate and covering the TFT driving circuit and the DBR reflective layer, wherein a first signal via connected to the MicroLED chip is defined in the planarization layer, and the first signal via is defined along the x-direction; The light emitted by the MicroLED chip can be reflected by the inner wall of the DBR reflective layer, and the light sequentially passes through the first surface and the second surface of the substrate and propagates to the outside.

2. The LED display unit according to claim 1, wherein: A signal electrode is further embedded in the first surface of the substrate, and a second signal via hole connected to the signal electrode is opened in the planarization layer.

3. The LED display unit according to claim 2, characterized in that: The signal electrode may be made of materials including, but not limited to, Ti, Cu, Mo, Ta, Au, Pt, Pd and ITO conductive films, and alloy films based on Ti, Cu, Mo, Ta, Au, Pt, Pd or ITO.

4. The LED display unit according to claim 1, wherein: The material of the substrate includes, but is not limited to, glass, ceramic and polyimide.

5. The LED display unit according to claim 1, wherein: The thickness of the MicroLED chip is 10 to 200 μm.

6. The LED display unit according to claim 1, characterized in that: The materials of the DBR reflective layer and the planarization layer include but are not limited to polyimide, epoxy resin and acrylic.

7. The LED display unit according to claim 6, characterized in that: The DBR reflective layer is covered with a metal reflective layer.

8. The LED display unit according to claim 7, characterized in that: The material of the metal reflective layer is ITO / Ag.

9. A display module, characterized in that: It comprises a driving backplane and a plurality of LED display units as claimed in any one of claims 1 to 8, wherein the LED display units are spliced ​​together and mounted on the driving backplane, and the driving backplane drives the LED display units to emit light.

10. A method for manufacturing the LED display unit according to any one of claims 1 to 8, characterized in that: include: fabricating the TFT driving circuit on the substrate; Mounting the MicroLED chip on the substrate; Fabricating the DBR reflective layer on the substrate, and evaporating a metal reflective layer on the DBR reflective layer; Forming the planarization layer on the substrate to cover the MicroLED chip and the DBR reflective layer, and opening the first signal via in the planarization layer; Physical vapor deposition technology is used to sputter metal copper on the first signal via to form a seed layer on the inner wall of the first signal via. The seed layer can be a single-layer film composed of copper or copper alloy, or a stacked structure of Ni / Cu, Mo / Cu, or Ti / Cu.

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