Micro light emitting diode module, display module thereof and repairing method thereof

Abstract

The micro light emitting diode module comprises at least three inverted micro light emitting diodes, the adjacent inverted micro light emitting diodes are connected through electrode pads, the polarities of the adjacent electrode pads are different, the negative electrode pads are connected through first lines, the positive electrode pads are connected through second lines, at least one first line is provided with a cuttable connecting point, and at least one second line is provided with a repairable breakpoint. Through the above structure, a relatively convenient and simple operation mode is provided for the repair work of the micro light emitting diode module, and the repair efficiency of the micro light emitting diode module is improved.

Description

Technical Field

[0001] The present invention relates to the field of LED technology, and in particular to a micro light emitting diode, a display module thereof, and a repair method thereof. Background Art

[0002] Micron-sized Mini / Micro LEDs have become a recent research hotspot due to their high brightness, contrast, color saturation, and local dimming capabilities. They are expected to replace LCDs and OLEDs as the next generation of displays, with potential applications in display screens, backlights, automotive lighting, wearable devices, and more. To achieve high pixel counts, Mini / Micro LEDs require extremely high density and quantity. Even a small defect can result in a high module defect rate. Therefore, rework is a key process in promoting the commercialization of Mini / Micro LED products. Effective rework in such a miniaturized, high-density arrangement is a pressing issue. Summary of the Invention

[0003] The purpose of the present invention is to overcome the problems existing in the prior art and provide a micro light emitting diode module that can effectively improve the yield rate of the manufacturing process.

[0004] The second object of the present invention is to provide a method for repairing a micro LED module.

[0005] The third object of the present invention is to provide a micro light emitting diode display module.

[0006] To solve the above technical problems, the following technical solutions are adopted:

[0007] A micro-LED module includes at least three flip-chip micro-LEDs, where adjacent flip-chip micro-LEDs are connected via electrode pads, and the polarities of adjacent electrode pads are different; the negative electrode pads are connected via a first circuit, and the positive electrode pads are connected via a second circuit; and the module is characterized in that at least one first circuit is provided with a cuttable connection point, and at least one second circuit is provided with a repairable breakpoint.

[0008] Preferably, it includes a first flip-chip micro-light-emitting diode, a second flip-chip micro-light-emitting diode, a third flip-chip micro-light-emitting diode, a first positive electrode pad, a second positive electrode pad, a first negative electrode pad, and a second negative electrode pad, and also includes a first circuit connecting the first negative electrode pad and the second negative electrode pad, and a second circuit connecting the first positive electrode pad and the second positive electrode pad.

[0009] Preferably, the size of the flip-chip micro light-emitting diode is less than 300 μm*300 μm.

[0010] Preferably, the connection point is a low melting point alloy connection point.

[0011] Preferably, the melting point of the low-melting-point alloy connection point is less than 217°C.

[0012] Preferably, the device further comprises a fluorescent conversion layer for white light conversion, wherein the fluorescent conversion layer is arranged on the inverted micro-light emitting diode.

[0013] Preferably, the micro-LED module forms a blue pixel, and the flip-chip micro-LED forms a blue sub-pixel.

[0014] A method for repairing a micro-LED module according to claim 1, wherein when a short circuit occurs in the flip-chip micro-LED connected to the first circuit, the connection point of the first circuit is cut off and the breakpoint of the second circuit is repaired;

[0015] Or when the first flip-chip micro-LED connected to the first circuit is broken, the connection point of the second circuit is repaired.

[0016] Alternatively, when a short circuit occurs in the flip-chip micro-LED connected to the first circuit, the connection point of the first circuit is cut off and the break point of the second circuit is repaired; when a short circuit occurs in the flip-chip micro-LED connected to the second circuit, the repaired point of the second circuit is cut off and the cut connection point of the first circuit is repaired;

[0017] Or when a short circuit occurs in the flip-chip micro-LED connected to the first circuit, the connection point of the first circuit is cut off and the break point of the second circuit is repaired; when a short circuit occurs in the flip-chip micro-LED connected to the second circuit, the cut connection point of the first circuit is repaired;

[0018] Or when the flip-chip micro-LED connected to the first circuit has a short circuit, the connection point of the second circuit is repaired; when the flip-chip micro-LED connected to the second circuit has a short circuit, the repaired point of the second circuit is cut off and the cut connection point of the first circuit is repaired; or when the flip-chip micro-LED connected to the first circuit has a short circuit, the connection point of the second circuit is repaired; when the flip-chip micro-LED connected to the second circuit has a short circuit, the cut connection point of the first circuit is repaired.

[0019] Preferably, the connection point of the first circuit is cut off by thermal fusing, cutting or chemical cutting.

[0020] Preferably, the breakpoint connection method is:

[0021] Apply flux to the traces on both sides of the breakpoint;

[0022] Place the metal sheet with low melting point alloy bumps on the flux spot;

[0023] Apply heat to connect the metal tabs to the traces on both sides of the break.

[0024] A micro-light emitting diode display module comprises at least one substrate, at least one pixel, and an IC driver, wherein the pixel comprises the micro-light emitting diode module according to any one of claims 1 to 7.

[0025] Preferably, the pixel points include red, green and blue sub-pixels, and the sub-pixels include the micro-light emitting diode module described in any one of claims 1 to 6.

[0026] Based on the above technical solution, the beneficial effects of the present invention are as follows:

[0027] 1. Through the above structure and method, the process yield of micro-light-emitting diodes is effectively improved and the cost is effectively reduced.

[0028] 2. Repair the micro LED module by repairing the circuit, avoiding secondary damage caused by directly repairing the micro LED;

[0029] 3. The difference in melting points between the alloy at the circuit connection point and the soldering alloy of the micro-LED can be used to avoid the impact of rework on the soldering of the micro-LED.

[0030] 4. The metal sheet with low-melting-point alloy bumps of the present invention facilitates circuit maintenance. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 This is a TOP schematic diagram of the blue light micro-LED module of the present invention.

[0032] Figure 2 This is a schematic diagram of the TOP structure of the pixel point of the micro-LED module in the present invention.

[0033] Figure 3 This is a diagram of the metal sheet with low-melting-point alloy bumps and the structure after connection in the present invention;

[0034] Figure 4 It is a schematic diagram of the TOP structure of the micro-LED display module of the present invention.

[0035] in:

[0036] 1—diode module; 11—blue pixel; 21—first positive electrode pad; 23—second positive electrode pad; 22—first negative electrode pad; 24—second negative electrode pad; 25—first flip-chip micro-LED; 26—second flip-chip micro-LED; 27—third flip-chip micro-LED; 28—first circuit; 281—connection point; 29—second circuit; 291—breakpoint; 31—circuit point; 32—circuit point; 33—low-melting-point alloy bump; 34—low-melting-point alloy bump; 35—metal sheet; 4—display module; 41—pixel; 411—red sub-pixel; 412—green sub-pixel; 413—blue sub-pixel; 42—IC driver; 43—substrate. DETAILED DESCRIPTION

[0037] The following description sets forth numerous specific details to facilitate a thorough understanding of the present invention. However, the present invention can be implemented in many other ways than those described herein, and those skilled in the art can make similar generalizations without departing from the scope of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0038] The technical solution of the present invention is described clearly and completely below with reference to specific embodiments and accompanying drawings.

[0039] The micro-LED module described in the present invention includes at least three flip-chip micro-LEDs, where adjacent flip-chip micro-LEDs are connected via electrode pads, and the polarities of adjacent electrode pads are different; the negative electrode pads are connected via a first circuit, and the positive electrode pads are connected via a second circuit; at least one first circuit is provided with a cuttable connection point, and at least one second circuit is provided with a repairable breakpoint.

[0040] By providing a disconnectable connection point on the first circuit, if all flip-chip micro-LEDs connected in series with the first circuit short-circuit, the connection point can be cut to disconnect the entire circuit, ensuring safe operation. At this point, simply repair the disconnection point on the second circuit and reconnect it, and the micro-LED module can be used again after repair. The disconnected connection point can be repaired as needed, and the repaired disconnection point can be disconnected as needed.

[0041] A method for repairing a micro-LED module according to the present invention:

[0042] When a short circuit occurs in the flip-chip micro-LED connected to the first circuit, the connection point of the first circuit is cut off and the breakpoint of the second circuit is repaired;

[0043] Or when the first flip-chip micro-LED connected to the first circuit is broken, the connection point of the second circuit is repaired.

[0044] Alternatively, when a short circuit occurs in the flip-chip micro-LED connected to the first circuit, the connection point of the first circuit is cut off and the break point of the second circuit is repaired; when a short circuit occurs in the flip-chip micro-LED connected to the second circuit, the repaired point of the second circuit is cut off and the cut connection point of the first circuit is repaired;

[0045] Or when a short circuit occurs in the flip-chip micro-LED connected to the first circuit, the connection point of the first circuit is cut off and the break point of the second circuit is repaired; when a short circuit occurs in the flip-chip micro-LED connected to the second circuit, the cut connection point of the first circuit is repaired;

[0046] Or when the flip-chip micro-LED connected to the first circuit has a short circuit, the connection point of the second circuit is repaired; when the flip-chip micro-LED connected to the second circuit has a short circuit, the repaired point of the second circuit is cut off and the cut connection point of the first circuit is repaired; or when the flip-chip micro-LED connected to the first circuit has a short circuit, the connection point of the second circuit is repaired; when the flip-chip micro-LED connected to the second circuit has a short circuit, the cut connection point of the first circuit is repaired.

[0047] The connection point of the first circuit is cut off by thermal fusing, cutting or chemical cutting.

[0048] The breakpoint connection method includes the following steps:

[0049] Apply flux to the traces on both sides of the breakpoint;

[0050] Place the metal sheet with low melting point alloy bumps on the flux spot;

[0051] Apply heat to connect the metal tabs to the traces on both sides of the break.

[0052] Example 1

[0053] See also Figure 1 , Figure 2 , Figure 3 , is a micro-LED module described in this embodiment. As shown in the figure, the micro-LED module 1 includes a plurality of blue pixels 11. The blue pixels 11 include a first flip-chip micro-LED 25, a second flip-chip micro-LED 26, a third flip-chip micro-LED 27, a first positive electrode pad 21, a second positive electrode pad 23, a first negative electrode pad 22, and a second negative electrode pad 24. It also includes a first line 28 connecting the first negative electrode pad 22 and the second negative electrode pad 24, and a second line 29 connecting the first positive electrode pad 21 and the second positive electrode pad 23.

[0054] The first circuit has a low melting point alloy connection point 281, and the second circuit has a repairable break point 291. The first circuit is conductive, and the break point of the second circuit remains disconnected.

[0055] In this embodiment, the size of the first flip-chip micro LED 25 , the second flip-chip micro LED 26 , and the third flip-chip micro LED 27 is 300 μm*300 μm.

[0056] The specific method for repairing the micro-LED module described in this embodiment is as follows: When the first flip-chip micro-LED 25 is short-circuited, the connection point 281 of the first circuit 28 is cut with a laser, and the break point 291 of the second circuit 29 is repaired and connected. When the first flip-chip micro-LED is open-circuited, the break point 291 of the second circuit is repaired and connected.

[0057] The repair method of the breakpoint 291 includes: first applying flux to the circuit points 31 and 32 on both sides of the breakpoint; placing a metal sheet 35 with low-melting-point alloy bumps (33 and 34) at the flux-applied location; and heating the metal sheet so that the low-melting-point alloy bumps (33 and 34) are connected to the circuits 31 and 32, respectively.

[0058] The metal sheet of the present invention is aluminum. The low-melting-point alloys 281, 33, and 34 are PbSn, which has a melting point of 185° C. The module also includes a fluorescent conversion layer for white light conversion, including quantum dots as a fluorescent conversion material and silicone as a fluorescent protective layer material.

[0059] Example 2

[0060] This embodiment is different from the first embodiment in that the size of the flip-chip micro-LED described in this embodiment is 130 μm*230 μm.

[0061] The connection point cutting method in this embodiment is chemical cutting.

[0062] The metal sheet in this embodiment is copper.

[0063] The low melting point alloys 281, 33, and 34 in this embodiment are BiSn, which has a melting point of 160°C.

[0064] The micro-LED module of this embodiment further includes a fluorescent conversion layer for white light conversion, and the fluorescent conversion layer includes a fluorescent conversion material β-sialon / K2SiF6 and a fluorescent protective layer material epoxy resin.

[0065] Example 3

[0066] This embodiment differs from embodiment 1 in that:

[0067] The size of the flip-chip micro LED in this embodiment is 50 μm*80 μm.

[0068] The cutting method of the connecting point of the present embodiment is chemical cutting.

[0069] The metal sheet of the present embodiment is silver.

[0070] The low melting point alloy 281, 33, 34 of the micro light emitting diode of the present embodiment is LnSn, and its melting point is 200℃.

[0071] The micro light emitting diode module of the present embodiment further comprises a fluorescent conversion layer for white light conversion, and the fluorescent conversion layer comprises a fluorescent conversion material γ-alon / SrLiAlN:Eu and a fluorescent protective layer material epoxy resin.

[0072] Embodiment 4

[0073] As Figure 4 The present embodiment is a display module 4 of red, green and blue micro light emitting diodes, which comprises at least one substrate 43, at least one pixel point 41, and an IC drive 42. The pixel point 41 is composed of red sub-pixel points 411, green sub-pixel points 412, and blue sub-pixel points 413. The sub-pixel points comprise the micro light emitting diode module as described in any one of embodiments 1-3.

[0074] The above is only the preferred embodiment of the present application, and does not limit the present application in any form. Any simple modification, equivalent change and modification of the above embodiment without departing from the technical solution of the present application, according to the technical essence of the present application, all still belong to the scope of the technical solution of the present application.

Claims

1. A micro-LED module comprising at least three flip-chip micro-LEDs, wherein adjacent flip-chip micro-LEDs are connected via electrode pads, and the polarities of adjacent electrode pads are different; the negative electrode pads are connected via a first circuit, and the positive electrode pads are connected via a second circuit; characterized in that: A cuttable connection point is provided on at least one first line, and a repairable breakpoint is provided on at least one second line; The connection point is a low-melting-point alloy connection point, and the melting point of the low-melting-point alloy connection point is less than 217° C. It includes a first flip-chip micro-LED, a second flip-chip micro-LED, a third flip-chip micro-LED, a first positive electrode pad, a second positive electrode pad, a first negative electrode pad, and a second negative electrode pad, and also includes a first circuit connecting the first negative electrode pad and the second negative electrode pad, and a second circuit connecting the first positive electrode pad and the second positive electrode pad; When the first flip-chip micro-LED is short-circuited, the connection point of the first circuit is cut off with a laser, and the breakpoint of the second circuit is repaired and connected; when the first flip-chip micro-LED is open-circuited, the breakpoint of the second circuit is repaired and connected.

2. The micro light emitting diode module according to claim 1, characterized in that: The size of the flip-chip micro light-emitting diode is less than 300 μm*300 μm.

3. The micro-LED module according to claim 1, wherein: It also includes a fluorescent conversion layer for white light conversion, and the fluorescent conversion layer is arranged on the inverted micro light emitting diode.

4. A method for repairing a micro-LED module according to any one of claims 1 to 3, characterized in that: The following steps are involved: When the first flip-chip micro-LED is short-circuited, the connection point of the first circuit is cut off with a laser, and the breakpoint of the second circuit is repaired and connected; when the first flip-chip micro-LED is open-circuited, the breakpoint of the second circuit is repaired and connected.

5. The method for repairing a micro LED module according to claim 4, wherein: The connection point of the first circuit is cut off by thermal fusing, cutting or chemical cutting.

6. The method for repairing a micro LED module according to claim 4, wherein: The connection method of the breakpoint: Apply flux to the traces on both sides of the breakpoint; Place the metal sheet with low melting point alloy bumps on the flux spot; Apply heat to connect the metal tabs to the traces on both sides of the break.

7. A micro-light emitting diode display module, characterized in that: It comprises at least one substrate, at least one pixel, and an IC driver, wherein the pixel comprises the micro light emitting diode module according to any one of claims 1 to 3.

8. The micro-LED display module according to claim 7, characterized in that: The pixel points include red, green, and blue sub-pixels, and the sub-pixels include the micro-light emitting diode module described in any one of claims 1 to 3.

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