Packaging structure and method of micro LED device and display device

Abstract

The present disclosure provides a packaging structure and method of a micro-LED device and a display device. The packaging structure of the micro-LED device comprises: a circuit board provided with a recess; a micro-LED device comprising a light-emitting chip and a driving chip, the light-emitting chip being located above the driving chip, the driving chip being arranged in the recess, and a chip pad on the upper surface of the driving chip being electrically connected with a circuit board pad located around the recess and on the upper surface of the circuit board; a heat-conducting insulating glue arranged between the recess and the driving chip; and a plastic encapsulating glue arranged on the micro-LED device and on the circuit board around the micro-LED device. According to the technical solution of the present disclosure, by arranging the micro-LED device in the recess of the circuit board, the packaging height can be effectively reduced, thereby meeting the miniaturization requirement of electronic products.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to the technical field of semiconductor LEDs, and in particular, to a packaging structure and method of a micro-LED device and a display device. BACKGROUND

[0002] In recent years, with the development of semiconductor process technology and the improvement of application demand, flexibility, miniaturization, array, and integration have become the research trend of LED devices. Similarly, the packaging process of micro-LED devices plays a crucial role in the performance and application of micro-LED devices.

[0003] However, the traditional micro-LED packaging technology is to adhere the micro-LED device to the circuit board through die bonding glue. Such packaging makes it difficult to meet the development demand of miniaturization of electronic devices. SUMMARY

[0004] To solve the technical problems mentioned in the background art, the present disclosure provides a packaging structure and method of a micro-LED device and a display device.

[0005] According to an aspect of an embodiment of the present disclosure, a packaging structure of a micro-LED device is provided. The packaging structure of the micro-LED device includes: a circuit board provided with a recess; a micro-LED device including a light-emitting chip and a driving chip, the light-emitting chip being located above the driving chip, the driving chip being arranged in the recess, and a chip pad on the upper surface of the driving chip being electrically connected to a circuit board pad on the upper surface of the circuit board around the recess; a thermally conductive insulating glue arranged between the recess and the driving chip; and a plastic encapsulating glue arranged on the micro-LED device and the circuit board around the micro-LED device.

[0006] Further, the upper surface of the driving chip is flush with the upper surface of the circuit board provided with the circuit board pad.

[0007] Further, the thermally conductive insulating glue is arranged at the bottom and the side of the driving chip.

[0008] Further, the chip pad and the circuit board pad are electrically connected by a wire, and the plastic encapsulating glue covers the micro-LED device, the circuit board pad, and the wire in a convex form.

[0009] According to another aspect of the present disclosure, a packaging method of a micro-LED device is also provided. The method comprises: opening a recess at a preset position on the circuit board according to the size of the micro-LED device, wherein the micro-LED device comprises a light-emitting chip and a driving chip, and the light-emitting chip is located above the driving chip; disposing a heat-conducting insulating glue at the bottom of the recess; disposing the driving chip of the micro-LED device on the heat-conducting insulating glue at the bottom of the recess; electrically connecting a chip solder pad located on the upper surface of the driving chip with a circuit board solder pad located around the recess and on the upper surface of the circuit board; and disposing plastic sealing glue on the micro-LED device and the circuit board around the micro-LED device.

[0010] Further, the depth of the recess is greater than the height of the driving chip, and the sum of the thickness of the heat-conducting insulating glue and the height of the driving chip is greater than the depth of the recess.

[0011] Further, the disposing of the driving chip of the micro-LED device on the heat-conducting insulating glue at the bottom of the recess comprises: placing the driving chip on the heat-conducting insulating glue at the bottom of the recess, and pressing the micro-LED device so that the upper surface of the driving chip is flush with the upper surface of the circuit board on which the circuit board solder pad is disposed.

[0012] Further, after the disposing of the driving chip of the micro-LED device on the heat-conducting insulating glue at the bottom of the recess, the packaging method further comprises: filling the heat-conducting insulating glue in the gap between the side of the driving chip and the recess.

[0013] Further, the electrically connecting of the chip solder pad located on the upper surface of the driving chip with the circuit board solder pad located around the recess and on the upper surface of the circuit board comprises: electrically connecting the chip solder pad with the circuit board solder pad by a wire.

[0014] Further, the disposing of the plastic sealing glue on the micro-LED device and the circuit board around the micro-LED device comprises: disposing the plastic sealing glue in a convex form to cover the micro-LED device, the circuit board solder pad, and the wire.

[0015] According to yet another aspect of the embodiments of the present disclosure, a display device is also provided. The display device comprises the packaging structure of the micro-LED device described above.

[0016] By disposing the micro-LED device in the recess of the circuit board, the packaging height can be effectively reduced, thereby meeting the miniaturization requirement of electronic products.

[0017] In addition, by arranging heat-conducting insulating glue around the driving chip, especially on the side, the heat dissipation area can be increased, thereby effectively improving heat dissipation and reducing junction temperature to meet the reliability requirements of electronic products. In addition, by arranging the plastic sealing glue in a convex shape, the light extraction efficiency can be improved and the light divergence angle can be reduced to meet the requirement of high brightness. BRIEF DESCRIPTION OF DRAWINGS

[0018] The above and other objects, features and advantages of the exemplary embodiments of the present disclosure will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which:

[0019] Figure 1 is a side view cross-sectional schematic diagram showing a packaging structure of a micro-LED device according to one embodiment of the present disclosure;

[0020] Figure 2 is a side view schematic diagram showing a micro-LED device according to one embodiment of the present disclosure;

[0021] Figure 3 is a flow chart showing a packaging method of a micro-LED device according to one embodiment of the present disclosure;

[0022] Figures 4a-4f is a process flow chart showing a packaging method of a micro-LED device according to one embodiment of the present disclosure. DETAILED DESCRIPTION

[0023] It should be noted that the embodiments and features in the embodiments in the present application can be combined with each other without conflict. The present disclosure will be described in detail below with reference to the accompanying drawings and in conjunction with the embodiments.

[0024] It should be noted that the following detailed description is exemplary and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the present application belongs.

[0025] For ease of description, spatial relative terms, such as "on", "above", "upper surface", "upper", and the like, can be used herein to describe the spatial relationship between one device or feature to another device or feature as shown in the drawings. It should be understood that the spatial relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientations depicted in the drawings. For example, if a device in the drawings is inverted, then a device described as "above" or "on" other devices or structures would then be oriented "below" or "on" the other devices or structures. Accordingly, the exemplary term "above" can encompass both an orientation of above and below. The devices can be otherwise oriented (rotated 90 degrees or at other orientations) and the spatial relative descriptions used herein interpreted accordingly.

[0026] Example embodiments according to the present disclosure will now be described in more detail with reference to the accompanying drawings. However, these example embodiments can be implemented in various different forms and should not be construed as being limited to the embodiments set forth herein. It should be understood that the embodiments are provided so that the present disclosure will be thorough and complete, and will fully convey the concept of the example embodiments to those skilled in the art, and in the drawings, the thicknesses of layers and regions are exaggerated for clarity, and the same reference numerals are used throughout the drawings to designate the same elements, and thus a description thereof will be omitted.

[0027] The present disclosure provides a packaging structure of a micro LED device. Referring to Figure 1 and Figure 2 , Figure 1 is a side view cross-sectional schematic diagram showing a packaging structure of a micro LED device according to one embodiment of the present disclosure, Figure 2 is a side view schematic diagram showing a micro LED device according to one embodiment of the present disclosure. As Figure 1 and Figure 2 shown, the packaging structure of the micro LED device 2 includes a circuit board 1 provided with a recess 122, a micro LED device 2 including a light emitting chip 21 and a driving chip 22, the light emitting chip 21 being located above the driving chip 22, the driving chip 22 being disposed in the recess 122, and a chip solder point 221 on an upper surface of the driving chip 22 being electrically connected to a circuit board solder point 121 located around the recess 122 and on an upper surface of the circuit board 1, a thermally conductive insulating adhesive 5 disposed between the recess 122 and the driving chip 22, and a plastic encapsulating adhesive 6 disposed on the micro LED device 2 and on the circuit board 1 around the micro LED device.

[0028] According to the packaging structure of the micro-LED device, by arranging the micro-LED device in the groove of the circuit board, the packaging height of the overall packaging structure can be effectively reduced, thereby meeting the miniaturization requirement of electronic products.

[0029] As shown in Figure 1 and Figure 2 , the circuit board 1 comprises a wiring part 11 for arranging wires and a chip placement part 12 for arranging the micro-LED device 2, and the circuit board solder point 121 is located at the upper surface of the chip placement part 12 and is electrically connected with the wires. Figure 1 As shown in , the chip solder point 221 can be electrically connected with the circuit board solder point 121 through the solder wire 4. Of course, the chip solder point 221 and the circuit board solder point 121 can also be electrically connected through any other applicable means.

[0030] In addition, the light-emitting chip 21 in the micro-LED device 2 can comprise an array of light-emitting units, such as a micro-LED array, and the driving chip 22 can comprise an array of driving units. For the sake of clarity, the drawings only schematically show one chip solder point 221 located on the upper surface of the driving chip 22 and one circuit board solder point 121 located on the circuit board, and one chip solder point 221 is electrically connected with one circuit board solder point 121 through the solder wire 4. It should be understood that the number of chip solder points 221 and circuit board solder points 121 and the corresponding connection relationship can be arranged as needed, which is not limited herein.

[0031] Further, the heat-conducting insulating glue 5 can be any applicable heat-conducting insulating glue, such as high-heat-conducting silicone glue, etc.

[0032] According to the embodiment of the present disclosure, the upper surface of the driving chip 22 can be flush with the upper surface of the circuit board 1 provided with the circuit board solder point 121. By such alignment arrangement, the chip solder point 221 and the circuit board solder point 121 can be kept at the same height.

[0033] Therefore, when the chip solder point 221 and the circuit board solder point 121 are electrically connected through the solder wire, the use of the solder wire can be facilitated, thereby improving the quality of the solder wire electrical connection, and at the same time, the length of the used solder wire is the shortest due to the same height of the two solder points. The material of the solder wire can comprise gold, copper, etc., and is preferably gold, so that the length of the gold wire can be saved, thereby reducing the cost.

[0034] According to an embodiment of the present disclosure, the heat-conducting insulating glue 5 is arranged on the bottom and side of the driving chip 22. By surrounding the bottom and side of the driving chip 22 with the heat-conducting insulating glue 5, the contact leakage between the driving chip 22 and the circuit board 1 can be prevented, and at the same time, the contact area of the heat-conducting insulating glue 5 with the driving chip 22 and the circuit board 1 can be effectively increased, so that the heat dissipation of the driving chip 22 to the circuit board 1 can be improved.

[0035] According to an embodiment of the present disclosure, the plastic sealing glue 6 covers the micro-LED device 2, the circuit board solder joint 121, and the wire 4 in a convex form. Specifically, the plastic sealing glue 6 covers the light-emitting chip 21 of the micro-LED device 2 in a convex form, which can effectively converge the light emitted by the light-emitting chip 21, improve the luminous flux and brightness, and at the same time, the light-emitting angle will also be smaller, which is beneficial to the uniformity of light emission.

[0036] The present disclosure also provides a packaging method of a micro-LED device. Referring to Figure 2 、 Figure 3 and Figures 4a-4f , Figure 3 is a flow chart illustrating a packaging method of a micro-LED device according to an embodiment of the present disclosure, Figures 4a-4f is a process flow chart illustrating a packaging method of a micro-LED device according to an embodiment of the present disclosure. The packaging method of the micro-LED device will be described below in combination with the above description of the packaging structure of the micro-LED device.

[0037] As shown in Figure 3 , the packaging method of the micro-LED device includes the following steps S101-S105.

[0038] Step S101: According to the size of the micro-LED device, a groove is opened at a predetermined position on the circuit board, wherein the micro-LED device includes a light-emitting chip and a driving chip, and the light-emitting chip is located above the driving chip.

[0039] Step S102: Heat-conducting insulating glue is arranged at the bottom of the groove.

[0040] Step S103: The driving chip of the micro-LED device is arranged on the heat-conducting insulating glue at the bottom of the groove.

[0041] Step S104: The chip solder joint located on the upper surface of the driving chip is electrically connected with the circuit board solder joint located around the groove and on the upper surface of the circuit board.

[0042] Step S105: Plastic sealing glue is arranged on the micro-LED device and the circuit board around the micro-LED device.

[0043] According to the technical scheme, the micro-LED device can be arranged in the groove of the circuit board, so that the packaging height can be effectively reduced, thereby meeting the miniaturization requirement of electronic products.

[0044] In step S101, a groove can be opened at a preset position on the circuit board according to the size of the micro-LED device, wherein the micro-LED device includes a light-emitting chip and a driving chip, and the light-emitting chip is located above the driving chip.

[0045] According to an embodiment of the present disclosure, referring to Figure 2 , Figure 4a and Figure 4b , the circuit board 1 includes a wiring part 11 for arranging wires and a chip mounting part 12 for arranging the micro-LED device 2, and a circuit board soldering point 121 is located at the upper surface of the chip mounting part 12 and is electrically connected with the wires. The micro-LED device 2 includes a light-emitting chip 21 and a driving chip 22, and the light-emitting chip 21 is located above the driving chip 22, and the upper surface of the driving chip 22 includes a chip soldering point 221. According to the size of the driving chip 22 of the micro-LED device 2, a groove 122 is opened at a preset position of the chip mounting part 12 of the circuit board 1, for example, by a milling machine, and in particular, the depth of the groove 122 is greater than the height of the driving chip 22, and specifically, the length, width and height (depth) of the groove 122 are slightly greater than the size of the driving chip 22.

[0046] In step S102, a heat-conducting insulating glue can be arranged at the bottom of the groove.

[0047] According to an embodiment of the present disclosure, referring to Figure 4c , a heat-conducting insulating glue 5 can be arranged at the bottom of the groove 122. The sum of the thickness of the heat-conducting insulating glue 5 and the height of the driving chip 22 is greater than the depth of the groove 122. The heat-conducting insulating glue can be, for example, high-heat-conducting silica gel or any applicable heat-conducting insulating glue.

[0048] In step S103, the driving chip of the micro-LED device can be arranged on the heat-conducting insulating glue at the bottom of the groove.

[0049] In known packaging technology, the heat-conducting insulating glue is directly arranged on the upper surface of the circuit board without opening a groove, and the micro-LED device is directly arranged on the heat-conducting insulating glue. According to an embodiment of the present disclosure, the driving chip 22 of the micro-LED device 2 can be arranged on the heat-conducting insulating glue 5 at the bottom of the groove 122. Therefore, the overall packaging height of the micro-LED device can be reduced, thereby reducing the size of the electronic product using the packaging structure, and being more conducive to the miniaturization of the electronic product.

[0050] According to another embodiment of the present disclosure, the disposing the driving chip of the micro-LED device on the thermally conductive insulating glue at the bottom of the groove can include: placing the driving chip on the thermally conductive insulating glue at the bottom of the groove, and pressing the micro-LED device, so that the upper surface of the driving chip is flush with the upper surface of the circuit board provided with the circuit board solder point.

[0051] Referring to Figure 4d , Figure 4d It is shown that after the driving chip placed on the thermally conductive insulating glue 5 at the bottom of the groove 122 is pressed, the upper surface of the driving chip 22 is flush with the upper surface of the circuit board 1 provided with the circuit board solder point 121. As described in steps S102 and S103, the depth of the groove 122 is greater than the height of the driving chip 22, and the sum of the thickness of the thermally conductive insulating glue 5 and the height of the driving chip 22 is greater than the depth of the groove 122. Therefore, by providing an appropriate amount of thermally conductive insulating glue 5 at the bottom of the groove 122, the upper surface of the driving chip 22 can be flush with the upper surface of the circuit board 1 provided with the circuit board solder point 121 after the micro-LED device on the thermally conductive insulating glue 5 is pressed.

[0052] According to an embodiment of the present disclosure, after this step S103, the thermally conductive insulating glue 5 can also be filled in the gap between the side of the driving chip 22 and the groove 122 as shown in Figure 4d There will be a gap between the side of the driving chip 22 of the micro-LED device 2 and the groove 122, and the gap is filled with the thermally conductive insulating glue 5, so that the thermally conductive insulating glue 5 surrounds the side and bottom of the driving chip, thereby allowing to prevent the contact leakage between the driving chip 22 and the circuit board 1, while the contact area of the thermally conductive insulating glue 5 with the driving chip 22 and the circuit board 1 can be effectively increased, and the heat dissipation of the driving chip 22 to the circuit board 1 can be improved.

[0053] In step S104, the chip solder point located on the upper surface of the driving chip can be electrically connected with the circuit board solder point located around the groove and on the upper surface of the circuit board.

[0054] According to an embodiment of the present disclosure, the electrically connecting the chip solder point located on the upper surface of the driving chip with the circuit board solder point located around the groove and on the upper surface of the circuit board can include: electrically connecting the chip solder point with the circuit board solder point by a wire. Referring to Figure 4eThe chip solder point 221 and the circuit board solder point 121 are electrically connected by the solder wire 4. Since the upper surface of the driving chip 22 where the chip solder point 221 is located is flush with the upper surface of the circuit board 1 where the circuit board solder point 121 is located. Therefore, when the chip solder point 221 and the circuit board solder point 121 are electrically connected by the solder wire 4, the use of the solder wire can be facilitated, thereby improving the quality of the solder wire electrical connection, and at the same time, the length of the solder wire used is the shortest due to the same height of the two solder points. The material of the solder wire may, for example, include gold, copper, etc., and is preferably gold, so that the length of the gold wire can be saved, thereby reducing the cost. Of course, the chip solder point 221 and the circuit board solder point 121 can also be electrically connected by any other applicable means.

[0055] In step S105, a plastic encapsulation glue is disposed on the micro-LED device and the circuit board around the micro-LED device.

[0056] According to embodiments of the present disclosure, with reference to Figure 4f The plastic encapsulation glue 6 covers the micro-LED device 2, the circuit board solder point 121, and the solder wire 4 in a convex form. In particular, the plastic encapsulation glue 6 covers the light-emitting chip 21 of the micro-LED device 2 in a convex form, which can effectively converge the light emitted by the light-emitting chip 21, improve the luminous flux and brightness, and at the same time, the light-emitting angle will also be smaller, which is beneficial to the uniformity of light emission.

[0057] The present disclosure also provides a display device. The display device includes the packaging structure of the micro-LED device described above. The display device may, for example, be a display screen applied to an electronic device. The electronic device may, for example, include a smartphone, a smartwatch, a notebook computer, a tablet computer, a driving recorder, a navigator, or any device with a display screen.

[0058] It should be noted that the terms used herein are only intended to describe specific embodiments and are not intended to limit exemplary embodiments according to the present application. As used herein, the singular form is intended to include the plural form unless the context clearly indicates otherwise, and it should also be understood that the terms "comprise" and / or "include" as used in the specification indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0059] It should be noted that the terms "first", "second", and the like, used in the description and the claims of the present application as well as above-mentioned figures are intended to distinguish similar objects and not to imply a specific order or chronology of events. It is to be understood that the data thus described can be interchanged, where appropriate, so that the embodiments of the present application described herein could be carried out in a different order than the one illustrated or described herein. Furthermore, the terms "comprising", "having", and any variations thereof, are intended to cover a non-exclusive inclusion, for example, a process, method, system, product, or apparatus that comprises a list of steps or units can not necessarily be limited to those steps or units that are clearly listed, but can include other steps or units that are not expressly listed or inherent to such process, method, product, or apparatus.

[0060] The preferred embodiments of the present application are described above in detail. The present application, however, is not limited to the precise embodiments described, and variations and modifications exist which would be apparent to one skilled in the art. It is intended to cover in the claims all such modifications and equivalents.

Claims

1. A packaging structure for a micro LED device, wherein, The packaging structure includes: A circuit board with grooves provided; A miniature LED device includes a light-emitting chip and a driver chip. The light-emitting chip is disposed on and above the driver chip. The driver chip is disposed in a groove, and chip solder joints on the upper surface of the driver chip are electrically connected to circuit board solder joints located around the groove and on the upper surface of the circuit board. Thermally conductive insulating adhesive is disposed between the groove and the driving chip; A molding compound is applied to the microLED device and the circuit board surrounding the microLED device.

2. The packaging structure of the micro LED device according to claim 1, wherein, The upper surface of the driver chip is flush with the upper surface of the circuit board where the circuit board solder joints are located.

3. The packaging structure of the micro LED device according to claim 1, wherein, The thermally conductive insulating adhesive is disposed on the bottom and sides of the driver chip.

4. The packaging structure of the micro LED device according to claim 1, wherein, The chip solder joints and the circuit board solder joints are electrically connected by bonding wires, and the encapsulant covers the micro LED device, the circuit board solder joints, and the bonding wires in a convex shape.

5. A packaging method for a micro LED device, wherein, The encapsulation method includes: According to the size of the micro LED device, a groove is made at a predetermined position on the circuit board. The micro LED device includes a light-emitting chip and a driver chip. The light-emitting chip is disposed on the driver chip and located above the driver chip. Thermally conductive insulating adhesive is applied to the bottom of the groove; The driving chip of the micro LED device is disposed on the thermally conductive insulating adhesive at the bottom of the groove; The chip solder joints located on the upper surface of the driver chip are electrically connected to the circuit board solder joints located around the groove and on the upper surface of the circuit board. A molding compound is applied to the microLED device and the circuit board surrounding the microLED device.

6. The packaging method for a micro LED device according to claim 5, wherein, The depth of the groove is greater than the height of the driving chip, and the sum of the thickness of the thermally conductive insulating adhesive and the height of the driving chip is greater than the depth of the groove.

7. The packaging method for a micro LED device according to claim 6, wherein, The process of placing the driver chip of the micro LED device on the thermally conductive insulating adhesive at the bottom of the groove includes: The driver chip is placed on the thermally conductive insulating adhesive at the bottom of the groove, and the micro LED device is pressed so that the upper surface of the driver chip is flush with the upper surface of the circuit board where the circuit board solder joints are located.

8. The packaging method for a micro LED device according to claim 5, wherein, After the driver chip of the micro-LED device is disposed on the thermally conductive insulating adhesive at the bottom of the recess, the encapsulation method further includes: The thermally conductive insulating adhesive is filled into the gap between the side of the driver chip and the groove.

9. The packaging method for a micro LED device according to claim 5, wherein, Electrically connecting the chip solder joints located on the upper surface of the driver chip to the circuit board solder joints located around the recess and on the upper surface of the circuit board includes: The chip solder joints are electrically connected to the circuit board solder joints by wire bonding.

10. The packaging method for a micro LED device according to claim 9, wherein, Applying encapsulant to the microLED device and the circuit board surrounding the microLED device includes: The encapsulant is arranged in a convex shape to cover the micro LED device, the circuit board solder joints, and the bonding wires.

11. A display device, wherein, The display device includes the packaging structure of the micro LED device according to any one of claims 1 to 4.

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