MIP box dam process and box dam process MIP lamp bead and support

Abstract

The invention discloses an MIP dam-enclosing technology, a dam-enclosing technology MIP lamp bead and a support, and relates to the technical field of LED packaging, and the method comprises the following steps: after the surface of the support is coated with solder paste, a light-emitting chip is positioned and fixed to a bonding pad area corresponding to the lamp bead surface of the support; the light-emitting chip is welded to the bonding pad area of the support through the eutectic bonding technology; grid-shaped box dam glue is dispensed on cutting seams between adjacent units of the support, and physical partitions between pixel points are formed; curing the box dam glue for the first time; carrying out glue packaging on the surface of the whole bracket; curing the packaging glue for the second time; the support is cut along the cutting seams to obtain independent lamp beads, light path crosstalk between adjacent pixel points is effectively blocked through the grid isolation structure design of the box dam glue, the light-emitting contrast ratio of the MIP packaging device is improved, the box dam glue area and the vertical projection of the cutting seams are designed in an overlapped mode, glue is prevented from covering a bonding pad light-emitting area, and light scattering losses are reduced.

Description

Technical Field

[0001] The present invention relates to the technical field of LED packaging, and more specifically to a MIP dam process and a dam process MIP lamp bead and a bracket. Background Art

[0002] In recent years, as display technology has developed rapidly towards high density and miniaturization, Micro LED display technology has become the core development direction of the new generation of display technology due to its self-luminescence, high brightness, long life and other characteristics. In the field of display device packaging, the RGB discrete devices used in the traditional surface mount (SMT) process can no longer meet the needs of ultra-small pitch display due to physical size limitations. Although the integrated packaging technology based on chip on board (COB) can achieve smaller pixel pitch, its secondary transfer yield and repairability still have technical bottlenecks.

[0003] In order to break through the limitations of existing technologies, the industry has proposed the Micro LED in Package (MIP) integrated packaging solution. This technology uses high-precision cutting of Mini / Micro LED chips to form single or multi-in-one microchip units, and combines mass transfer technology to arrange the microchips in an array on a carrier with high-precision circuits. The fan-out packaging process forms an independent package, and then realizes display device manufacturing through light splitting, color mixing and modular integration. Compared with COB technology, the MIP solution retains the high reliability advantage of chip-level integration and has the process compatibility of discrete devices, significantly reducing the difficulty of later testing and mounting processes.

[0004] In terms of specific implementation, the MIP package uses a flip-chip structure to break through the limitations of the traditional LED bracket injection molding process, so that the size of a single package can be reduced to less than 0.8mm, which is a significant improvement over the physical limit of 1mm×1mm of traditional RGB devices. However, this technology faces unique optical challenges in practical applications: since the miniaturized package forms discrete light-emitting units after cutting, the superposition of the light-emitting angles between adjacent lamp beads will cause light interference, which is specifically manifested as halo crosstalk and contrast degradation between adjacent pixels. This problem is particularly prominent in small-pitch display applications, which seriously restricts the application and expansion of MIP technology in the field of high-end displays. How to effectively control the light interference effect between discrete micropackages has become a key technical problem that needs to be solved urgently in this field.

[0005] Based on this, the present invention provides a MIP dam process and a dam process MIP lamp bead and a bracket. Summary of the invention

[0006] In order to solve the problems raised in the above background technology, the present invention provides a MIP dam process and a dam process MIP lamp bead and a bracket.

[0007] The present invention provides a MIP dam process, and the MIP lamp beads and brackets adopt the following technical solutions:

[0008] A MIP dam process includes the following steps:

[0009] Step 1: After applying solder paste on the surface of the bracket, position and fix the light-emitting chip on the pad area corresponding to the lamp bead surface of the bracket;

[0010] Step 2: Weld the light-emitting chip to the pad area of the bracket through an eutectic soldering process;

[0011] Step 3: Dot-grid-shaped dam glue at the cutting seams between adjacent units of the bracket to form a physical partition between pixel points;

[0012] Step 4: Cure the dam glue for the first time;

[0013] Step 5: Encapsulate the entire surface of the bracket with glue;

[0014] Step 6: Cure the encapsulating glue for the second time;

[0015] Step 7: Cut the bracket along the cutting seam to obtain independent lamp beads, where the cutting path coincides with the dam glue area, so that a dam structure is formed around the lamp beads.

[0016] Preferably, the coating method of the grid-shaped dam glue is strip-shaped glue lines arranged at intervals.

[0017] Preferably, the temperature range for the first curing and the second curing is 80°C - 160°C, and the curing time is 30 - 240 min.

[0018] Preferably, the glue encapsulation uses transparent silicone or epoxy resin, and the encapsulation thickness is 1.2 - 1.5 times the height of the light-emitting chip.

[0019] Preferably, the width of the dam glue is greater than the width of the cutting seam.

[0020] Preferably, the material of the dam glue is ultraviolet light-curable glue or thermosetting epoxy resin.

[0021] A dam process MIP lamp bead is prepared according to the above-mentioned MIP dam process.

[0022] Preferably, the bracket includes a BT substrate, which has a lamp bead surface and a pin surface; the lamp bead surface is provided with unit areas arranged in an array, each unit corresponding to a pixel point, and metallized vias penetrating the BT substrate are provided at the four corners of the unit for electrical connection between the lamp bead surface and the pin surface; cutting slits are provided between adjacent units, and a dam glue filling area is correspondingly arranged directly above the cutting slits; the lamp bead surface forms a metal circuit layer with a pad pattern through PCB technology, which includes metallized vias formed by drilling and copper deposition, circuit patterns formed by film pasting, exposure, and development processes, and stepped pad structures formed by electroplating and etching processes, and the pad surface is not covered by a solder mask layer; the dam glue filling area completely coincides with the cutting slit in the vertical projection, and the width of the dam glue filling area is wider than that of the cutting slit.

[0023] In summary, the present invention includes the following beneficial technical effects:

[0024] 1. Through the design of the dam glue grid isolation structure, the optical path crosstalk between adjacent pixel points is effectively blocked, improving the light emission contrast of the MIP packaging device. Moreover, the design that the dam glue area coincides with the vertical projection of the cutting slit avoids the colloid covering the light-emitting area of the pad and reduces the light scattering loss.

[0025] 2. Based on the integrated bracket structure of the BT substrate, the eutectic soldering process is directly used for die bonding, eliminating the secondary processing link of the traditional ceramic substrate and reducing the comprehensive packaging cost; combined with the PCB standard manufacturing process (drilling - copper deposition - etching), high-precision metal pads and vias are formed, and the processing efficiency is greatly improved compared with the traditional RGB bracket.

[0026] 3. The MIP dam process uses dam glue to isolate between units, which has higher producibility and precision compared with film pasting or other processes. The MIP bracket has an integrated design, and the metal pads use multiple coatings. The lamp bead life, welding thrust, moisture resistance, and storage resistance are all greatly improved compared with the traditional RGB bracket. Cutting slits are reserved between the bracket units, and the appearance dimensions are more consistent after the lamp beads are cut. After the dam glue of the MIP dam process is cured, the whole board is sealed with glue, and the lamp beads have a large light-emitting angle, less scattering, and good appearance consistency.

[0027] The above summary is only for the purpose of the specification and is not intended to be limiting in any way. In addition to the above-described illustrative aspects, embodiments, and features, further aspects, embodiments, and features of the present invention will become apparent by reference to the drawings and the following detailed description. Description of the Drawings

[0028] Figure 1 is a flow chart of a MIP dam process in an embodiment of the present invention;

[0029] Figure 2a is a schematic diagram of an unbonded chip bracket, b is a schematic diagram of a bonded chip bracket, c is a schematic diagram of a bracket with dam glue applied, and d is a schematic diagram of the finished product after bracket cutting;

[0030] Figure 3 e is a side schematic diagram of an unbonded chip bracket, f is a side schematic diagram of a bonded chip bracket, g is a side schematic diagram of a bracket with dam glue applied, and h is a side schematic diagram of the finished product after bracket cutting;

[0031] Figure 4 is a schematic diagram of the structure of the lamp bead surface of a dam process MIP lamp bead in an embodiment of the present invention;

[0032] Figure 5 is a schematic diagram of the structure of the pin surface of a dam process MIP lamp bead in an embodiment of the present invention;

[0033] Figure 6 is a schematic diagram of the sectional structure of a dam process MIP lamp bead in an embodiment of the present invention;

[0034] Figure 7 is a schematic diagram of the structure of the lamp bead surface of the bracket in an embodiment of the present invention;

[0035] Figure 8 is a schematic diagram of the structure of the pin surface of the bracket in an embodiment of the present invention.

[0036] Explanation of reference numerals: 1, BT substrate; 2, lamp bead surface; 3, pin surface; 4, metallized through hole; 5, cutting seam; 6, dam glue filling area; 7, dam; 8, light-emitting chip; 9, encapsulation glue; 10, pin; 11, hole ring. Detailed implementation manners

[0037] The following will further elaborate on the present invention in conjunction with the attached Figures 1 to 8 drawings.

[0038] It should be noted that the drawings are schematic and not drawn to scale. For the sake of clarity and convenience in the figures, the relative sizes and proportions of the parts shown in the figures are exaggerated or reduced in size for illustration, and any dimensions are merely exemplary and not limiting. In addition, the same reference numerals are used for the same structures, elements, or fittings that appear in more than two figures to represent similar features.

[0039] Embodiment 1

[0040] An embodiment of the present invention discloses a MIP dam process. Referring to Figures 1 to 3 , a MIP dam process includes the following steps:

[0041] Step 1: After applying solder paste on the surface of the bracket, position and fix the light-emitting chip on the corresponding pad area of the lamp bead surface of the bracket;

[0042] Step 2: Solder the light-emitting chip to the pad area of the bracket through eutectic soldering process;

[0043] Step 3: Dot grid-shaped dam glue at the cutting seams between adjacent units of the bracket to form a physical partition between pixel points;

[0044] Step 4: Cure the dam glue for the first time;

[0045] Step 5: Encapsulate the entire surface of the bracket with glue;

[0046] Step 6: Cure the encapsulating glue for the second time;

[0047] Step 7: Cut the bracket along the cutting seams to obtain independent lamp beads, where the cutting path coincides with the dam glue area, so that a dam structure is formed around the lamp beads.

[0048] Specifically, the coating method of the grid-shaped dam glue is strip-shaped glue lines arranged at intervals.

[0049] Specifically, the temperature range for the first curing and the second curing is 80°C - 160°C, and the curing time is 30 - 240 min.

[0050] Specifically, the glue encapsulation uses transparent silicone or epoxy resin, and the encapsulation thickness is 1.2 - 1.5 times the height of the light-emitting chip.

[0051] Specifically, the width of the dam glue is greater than the width of the cutting seam.

[0052] Specifically, the material of the dam glue is ultraviolet light-curable glue or thermosetting epoxy resin.

[0053] Through the design of the dam glue grid-shaped isolation structure, the optical path crosstalk between adjacent pixel points is effectively blocked, improving the light-emitting contrast of the MIP packaging device. And the design that the vertical projection of the dam glue area coincides with the cutting seam avoids the colloid covering the pad light-emitting area and reduces the light scattering loss;

[0054] Based on the integrated bracket structure of the BT substrate, eutectic soldering process is directly used for die bonding, eliminating the secondary processing link of the traditional ceramic substrate, reducing the comprehensive packaging cost; combined with the PCB standard process (drilling - copper deposition - etching) to form high-precision metal pads and vias, the processing efficiency is greatly improved compared with the traditional RGB bracket;

[0055] Through the collaborative design of metallized vias (quadrilateral layout) and cutting seams, the pixel unit pitch is reduced, and the pixel density per unit area is improved compared with the conventional RGB packaging; the micron-level dot coating process of the dam glue replaces the traditional film pasting isolation technology, breaking through the physical limit and improving the yield;

[0056] The MIP dam process units are separated from each other by dam glue, which has higher productivity and precision compared to film laminating or other processes. The MIP bracket has an integrated design, and the metal pads use multiple coatings. The lamp bead lifespan, welding thrust, moisture resistance, and storage resistance are all significantly improved compared to traditional RGB brackets. There are cutting seams reserved between the bracket units, and the appearance dimensions of the lamp beads are more consistent after cutting. After the dam glue of the MIP dam process cures, the entire board is sealed with glue. The lamp beads have a large emission angle, less scattering, and good appearance consistency.

[0057] Example Two

[0058] An embodiment of the present invention discloses a MIP lamp bead with a dam process. Refer to Figure 4 、 Figure 5 and Figure 6 , a MIP lamp bead with a dam process, which is prepared according to the above-mentioned MIP dam process.

[0059] Specifically, the periphery of the lamp bead is a dam 7, and in the middle are a light-emitting chip 8 and an internal connection circuit. The lamp bead has a four-pin (pin 10) design. The pads of the internal light-emitting chips are connected through the metal wiring of the bracket and can freely switch the RGB sequence and electrode placement. At the same time, the position of the round pins is the common electrode position, supporting both common anode and common cathode pin designs. The dam 7 is coated with encapsulation glue 9, and a hole ring 11 is arranged around the metallized via 4.

[0060] The light-emitting chip 8 is isolated from adjacent lamp beads through the dam structure 7, and the light path is optimized by combining the encapsulation glue 9, making the emission angle larger (compared to the existing ones), improving the light efficiency utilization rate, suppressing light crosstalk, and increasing the contrast. The four-pin design and the metal wiring of the bracket support the free switching of the RGB sequence and the common anode / common cathode electrodes, adapting to diverse display requirements.

[0061] Example Three

[0062] An embodiment of the present invention discloses a bracket. Refer to Figure 7 and Figure 8 , the bracket includes a BT substrate 1, and the BT substrate 1 has a lamp bead surface 2 and a pin surface 3; there are arrayed unit areas on the lamp bead surface 2, each unit corresponding to a pixel point. Metalized vias 4 penetrating the BT substrate 1 are provided at the four corners of the unit for electrical connection between the lamp bead surface 2 and the pin surface 3; cutting seams 5 are provided between adjacent units, and a dam glue filling area 6 is correspondingly arranged directly above the cutting seams 5; the lamp bead surface 2 forms a metal circuit layer with a pad pattern through PCB technology, which includes the metallized vias 4 formed by drilling and copper deposition, the circuit pattern formed by film laminating - exposure - development technology, and the stepped pad structure formed by electroplating - etching treatment. The surface of the pads is not covered by a solder mask layer; the dam glue filling area 6 and the cutting seams 5 completely overlap in the vertical projection, and the width of the dam glue filling area 6 is wider than that of the cutting seams 5.

[0063] Specifically, the lamp bead surface 2 and the pin surface 3 of the BT substrate 1 adopt a layered structure, and high-precision electrical interconnection is achieved by combining four-corner metallized vias 4. A stepped pad and a solder mask-free layer circuit are formed through PCB technology to improve welding reliability and signal transmission efficiency; the vertical projection of the dam glue filling area 6 completely coincides with the cutting seam 5 and has a larger width, ensuring that the dam glue completely wraps the cutting seam during cutting to avoid burrs or colloid tearing; at the same time, the collaborative design of the metallized via 4 and the cutting seam 5 supports high-density pixel arrangement, combined with the physical isolation of light crosstalk by the dam glue, improving the display contrast and comprehensively solving the problems of complex traditional bracket technology, low reliability, and light interference.

[0064] The standard parts used in the present invention can all be purchased from the market. The special-shaped parts can be customized according to the description in the specification and the drawings. The specific connection methods of each part all adopt conventional means such as bolts, rivets, and welding that are mature in the prior art. The machinery, parts, and equipment all adopt conventional models in the prior art, and the circuit connection adopts the conventional connection method in the prior art, which will not be elaborated here.

[0065] In the description of the present invention, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of such features. The meaning of "a plurality" is two or more, unless otherwise specifically defined.

[0066] In the present invention, unless otherwise clearly specified and limited, the terms "mounted", "connected", "connected to", "fixed", etc. should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or integrated; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the internal communication of two components or the interaction relationship between two components. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0067] In the present invention, unless otherwise clearly specified and limited, the first feature being "on" or "under" the second feature can be that the first and second features are in direct contact, or the first and second features are indirectly in contact through an intermediate medium. Moreover, the first feature being "above", "over", and "on" the second feature can be that the first feature is directly above or obliquely above the second feature, or simply indicates that the first feature has a higher horizontal height than the second feature. The first feature being "under", "below", and "beneath" the second feature can be that the first feature is directly below or obliquely below the second feature, or simply indicates that the first feature has a lower horizontal height than the second feature.

[0068] In the description of this specification, the descriptions referring to terms such as "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. 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 a suitable manner in any one or more embodiments or examples. In addition, without contradiction, those skilled in the art can combine and combine the different embodiments or examples described in this specification and the features of different embodiments or examples.

[0069] In the accompanying drawings of the disclosed embodiments of the present invention, only the structures related to the disclosed embodiments are involved, and other structures can refer to the general design. Without conflict, the same embodiment and different embodiments of the present invention can be combined with each other.

[0070] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A MIP dam process, characterized in that, It includes the following steps: Step 1: After applying solder paste on the surface of the bracket, position and fix the light-emitting chip on the pad area corresponding to the bead surface of the bracket; Step 2: Solder the light-emitting chip to the pad area of the bracket through the eutectic soldering process; Step 3: Dot-grid-shaped dam glue at the cutting seams between adjacent units of the bracket to form a physical partition between pixel points; Step 4: Cure the dam glue for the first time; Step 5: Glue-encapsulate the entire surface of the bracket; Step 6: Cure the encapsulating glue for the second time; Step 7: Cut the bracket along the cutting seam to obtain independent beads, where the cutting path coincides with the dam glue area, so that a dam structure is formed around the beads.

2. The MIP cofferdam process according to claim 1, wherein: The coating method of the grid-shaped dam glue is strip-shaped glue lines arranged at intervals.

3. The MIP cofferdam process according to claim 1, wherein: The temperature range for the first curing and the second curing is 80°C - 160°C, and the curing time is 30 - 240 min.

4. A MIP cofferdam process according to claim 1, characterized in that: The glue encapsulation uses transparent silicone or epoxy resin, and the encapsulation thickness is 1.2 - 1.5 times the height of the light-emitting chip.

5. A MIP dam building process according to claim 1, characterized in that: The width of the dam glue is greater than the width of the cutting seam.

6. The MIP cofferdam process according to claim 1, wherein: The material of the dam glue is ultraviolet-curable glue or thermosetting epoxy resin.

7. A dam-building process MIP lamp bead, characterized in that: Prepared according to any one of claims 1 - 6 by a MIP dam process.

8. A MIP dike construction process according to claim 1, characterized in that: The bracket includes a BT substrate (1), and the BT substrate (1) has a bead surface (2) and a pin surface (3); The bead surface (2) is provided with an array of unit areas, each unit corresponding to a pixel point, and metallized vias (4) penetrating the BT substrate (1) are provided at the four corners of the unit for electrical connection between the bead surface (2) and the pin surface (3); A cutting seam (5) is provided between adjacent units, and a dam glue filling area (6) is correspondingly arranged directly above the cutting seam (5); The bead surface (2) forms a metal circuit layer with a pad pattern through PCB technology, which includes metallized vias (4) formed by drilling - copper deposition, circuit patterns formed by film pasting - exposure - development technology, and stepped pad structures formed by electroplating - etching treatment, and the pad surface is not covered by a solder mask layer; The dam glue filling area (6) completely coincides with the cutting seam (5) in the vertical projection, and the width of the dam glue filling area (6) is wider than the cutting seam (5).

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