Preparation method, product and application of microminiature high-integration-level colorful LED (light-emitting diode) lamp bead

Abstract

The invention discloses a microminiature high-integration-level colorful LED lamp bead preparation method, a product and application thereof, and relates to the field of semiconductor light-emitting devices and microelectronic packaging, the preparation method comprises the following steps: providing a microminiature packaging support, and the microminiature packaging support is provided with four electrical pins; a driving chip and at least one group of RGB LED chips are fixed in a designated area of a packaging support through a die bonding technology, and the driving chip and the RGB LED chips are integrated in the same packaging body; establishing electrical connection between the driving chip and the RGB LED chip and between the driving chip and the four electrical pins through a wire bonding process; carrying out molding packaging on the chip combination subjected to wire bonding by adopting packaging colloid to form a lamp bead main body; carrying out curing treatment on the packaging colloid; carrying out photoelectric property test on the cured lamp bead; according to the preparation method, the space utilization efficiency and the signal integrity are remarkably improved, and an efficient heat dissipation path is constructed through collaborative design of the pins and the packaging body.

Description

Technical Field

[0001] This invention relates to semiconductor light-emitting devices and microelectronic packaging technology, specifically to a method for preparing micro-sized, highly integrated, colorful LED beads, the product, and its application. Background Technology

[0002] Light-emitting diodes (LEDs) are widely used in general lighting, display backlighting, outdoor large screens, and indicator lights for various electronic devices due to their advantages such as energy saving, long lifespan, high brightness, and rich colors. With the rapid development of consumer electronics, wearable devices, automotive displays, and ultra-high-definition micro-pitch displays, the market has placed unprecedented demands on LED devices for miniaturization, high integration, and high performance. Among these, dynamic color-changing LED chips have become a hot topic in technological development due to their superior performance in personalized lighting, dynamic displays, and atmosphere creation.

[0003] Currently, the colorful LED beads on the market mainly adopt the following two technical solutions:

[0004] The first type is a discrete component + external driver solution. This solution typically packages three independent LED chips (red, green, and blue) into a single LED bead, but the driver and control circuitry (IC) is external to the LED bead. In use, multiple LED beads must be connected to an external driver controller via complex printed circuit board (PCB) wiring. The main drawback of this solution is:

[0005] Low integration and large size: The external driver IC and complex wiring occupy a lot of space, making it difficult to reduce the size of the entire light-emitting module, which cannot meet the demanding requirements of ultra-miniature devices such as smartwatches and AR / VR glasses.

[0006] The system is complex and its reliability is questionable: The large number of solder joints and external connection lines increases the system complexity and makes it prone to problems such as poor contact, signal interference, and soldering failure, which reduces the long-term reliability of the product.

[0007] Low production efficiency and high cost: Additional surface mount and assembly processes are required at the application end to install the driver IC, which increases the production process steps and material costs.

[0008] The second type is the SMD LED chip solution with integrated driver IC. For example, Chinese Patent Publication No. CN116598298A discloses a color-bias-free display screen and its full-color SMD LED chips. To simplify applications, the industry has developed products that integrate the control IC and LED chip into larger-sized (e.g., 5050, 3535) LED chips. While this solves some of the external driver issues, it still has significant shortcomings:

[0009] Size remains a limitation: Due to limitations in traditional packaging processes and thermal management capabilities, the size of these integrated LED chips is difficult to further miniaturize to 1515 (1.5mm × 1.5mm) or smaller, which restricts their application in ultra-high density displays (such as Micro LED splicing screens) and extremely compact spaces.

[0010] The conflict between heat dissipation and performance: Integrating a heat-generating driver IC and multiple LED chips into a miniaturized package leads to a high concentration of heat. Poor heat dissipation design will cause the chip junction temperature to rise rapidly, resulting in decreased luminous efficacy, color temperature drift, and wavelength shift, severely shortening the device lifespan and becoming a key bottleneck restricting the performance of miniature RGB LED chips.

[0011] Pin and circuit design redundancy: Some early designs used a large number of pins or failed to optimize the circuit design, resulting in complex PCB routing at the application end, which is not conducive to achieving high-density, low-cost array layout.

[0012] In summary, existing multi-color LED technology struggles to achieve an ideal balance between miniaturization, high integration, high reliability, and excellent heat dissipation. Therefore, the industry urgently needs an innovative technical solution that can efficiently and reliably integrate drive control circuits with multi-color LED chips within extremely limited physical space (e.g., 1.5mm × 1.5mm and below), fundamentally solving a series of problems related to electrical interconnection, heat dissipation management, and signal integrity, thereby driving the further development of micro-displays and miniaturized electronic devices. Summary of the Invention

[0013] The purpose of this invention is to provide a method for preparing micro-sized, highly integrated, colorful LED beads, as well as their applications, to solve the problems of large size, poor stability, difficult heat dissipation, and complex preparation in the existing technology.

[0014] To achieve the above objectives, the present invention provides the following technical solution: a method for manufacturing micro-sized, highly integrated, multi-colored LED beads, comprising the following steps:

[0015] S1: Substrate preparation, providing a miniaturized packaging bracket with four electrical pins;

[0016] S2: Die bonding, which fixes the driver chip and at least one set of RGB LED chips to a designated area of ​​the package bracket through a die bonding process, with the driver chip and RGB LED chips integrated into the same package.

[0017] S3: Wire bonding, through the wire bonding process, establishes electrical connections between the driver chip and the RGB LED chip, as well as between the driver chip and the four electrical pins;

[0018] S4: Encapsulation and molding, using an encapsulating colloid with predetermined light transmittance and refractive index to mold and encapsulate the chip assembly with completed wire bonding to form the main body of the lamp bead;

[0019] S5: Curing, the encapsulating colloid is cured;

[0020] S6: Testing and sorting. The photoelectric performance of the cured LED beads is tested, and the beads are sorted according to the test results to obtain the finished LED beads.

[0021] Furthermore, the four electrical pins are configured as a minimal pin set to achieve data signal transmission, power supply, and grounding functions. At least one pin in this minimal pin set is configured to have multiplexing functionality for both signal and power transmission.

[0022] Furthermore, the functions of the four electrical pins are defined as follows:

[0023] The first pin (PIN1) is configured as a data input pin (DIN) and also serves as a power supply pin during the power-on initialization phase.

[0024] The second pin (PIN2) is configured as the positive power supply pin (VDD).

[0025] The third pin (PIN3) is configured as a data output pin (DOUT);

[0026] The fourth pin (PIN4) is configured as the negative power supply pin (GND).

[0027] Furthermore, in the die bonding process of S2, a high thermal conductivity insulating adhesive is used to fix the driver chip and the RGB LED chip onto the pads of the package bracket. The pin layout of the package bracket and the shape of the pads are optimized to form a heat dissipation path with low thermal resistance.

[0028] Furthermore, in the wire bonding process of S3, gold or copper wires are used for wire bonding. The driver chip integrates a single-wire serial communication interface and a PWM dimming circuit. The independent control of each color chip of the RGB LED is achieved by the driver chip through wire bonding.

[0029] Furthermore, in the encapsulation molding step of S4, the encapsulating colloid is silicone or epoxy resin doped with scattering particles. The scattering particles are used to make the light emitted by the RGB LED chip mix evenly and expand the light emission angle.

[0030] Furthermore, the process parameters for the curing step in S5 are: a curing time of 1.5 to 3 hours at a temperature of 120°C to 150°C.

[0031] Furthermore, the testing and sorting steps in S6 include testing the color coordinates, brightness, voltage, and communication functions of the LED beads to ensure that the color synchronization error is less than ±1% and that 256 levels of grayscale adjustment can be achieved.

[0032] A miniature, highly integrated RGB LED bead is prepared using the above-mentioned method. The bead has a package size of 1.5mm × 1.5mm × 1.0mm and integrates a driver chip and at least one set of RGB LED chips. It achieves power supply, data input and output functions through only four exposed pins.

[0033] Furthermore, miniature, highly integrated, colorful LED beads are used in miniature display and lighting devices (display screens, smart wearable devices, automotive interior lighting, decorative lighting, or IoT terminal devices).

[0034] A miniature display and lighting device includes multiple miniature, highly integrated, multicolored LED beads, which are cascaded in sequence through their data output pin (DOUT) and data input pin (DIN) to form a display pixel array.

[0035] Compared with existing technologies, this invention provides a method for fabricating, producing, and applying miniaturized, highly integrated RGB LED chips. At the fabrication process level, it introduces chip-level integrated integration and die bonding processes, utilizing a miniaturized packaging bracket and an optimized four-pin electrical architecture design to achieve high-density heterogeneous integration of the driver IC and RGB LED chip within a single chip. At the system application level, it simplifies external circuitry and connections, significantly improves space utilization efficiency and signal integrity, and constructs an efficient heat dissipation path through the collaborative design of the pins and package. Specific technical effects include the following:

[0036] 1. The driving circuit, control logic and RGB light-emitting unit are all integrated into a package with a size of less than 2.0mm×2.0mm, and the number of pins is reduced to four, providing core component support for the ultra-high density pixel layout and ultra-thin design of terminal devices.

[0037] 2. By using die bonding and bonding processes to replace traditional wire connections that are prone to failure, the risk of contact resistance and poor soldering is reduced. The optimized packaging structure enhances mechanical strength and heat dissipation, effectively suppressing light decay and color drift of the LED chips under long-term high-load operation.

[0038] 3. The standardized four-pin design supports serial cascading, which greatly simplifies the PCB routing complexity at the application end and reduces the difficulty of system assembly; at the same time, the integrated manufacturing process reduces production steps, improves production efficiency and yield, thereby reducing overall costs. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0040] Figure 1 This is a schematic diagram of the preparation process of Embodiment 1 of the present invention;

[0041] Figure 2 This is a schematic diagram of the packaging structure of the micro-sized, highly integrated, colorful LED lamp beads in Embodiment 1 of the present invention.

[0042] Explanation of reference numerals in the attached figures:

[0043] 1. Package bracket; 2. Electrical pins; 3. Driver chip; 4. RGB LED chip. Detailed Implementation

[0044] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0045] As attached Figure 1 To be continued Figure 2 As shown:

[0046] Example 1:

[0047] This invention provides a method for fabricating micro-sized, highly integrated, colorful LED beads, comprising the following steps:

[0048] S1: Substrate preparation, providing a miniaturized packaging bracket 1 with four electrical pins 2; the four electrical pins 2 are configured as a minimized pin set to realize data signal transmission, power supply and grounding functions. In the minimized pin set, at least one pin is configured to have multiplexing function for signal transmission and power transmission;

[0049] S2: Die bonding, fixing the driver chip 3 and at least one set of RGB LED chips 4 to a designated area of ​​the package bracket 1 through a die bonding process, with the driver chip 3 and RGB LED chips 4 integrated into the same package body;

[0050] S3: Wire bonding, through wire bonding process, establish electrical connections between driver chip 3 and RGB LED chip 4, and between driver chip 3 and four electrical pins 2;

[0051] S4: Encapsulation and molding, using an encapsulating colloid with predetermined light transmittance and refractive index to mold and encapsulate the chip assembly with completed wire bonding to form the main body of the lamp bead;

[0052] S5: Curing, the encapsulating colloid is cured;

[0053] S6: Testing and sorting. The photoelectric performance of the cured LED beads is tested, and the beads are sorted according to the test results to obtain the finished LED beads.

[0054] 1. In one embodiment of the present invention, the functions of the four electrical pins 2 are defined as follows:

[0055] The first pin (PIN1) is configured as a data input pin (DIN) and also serves as a power supply pin during the power-on initialization phase.

[0056] The second pin (PIN2) is configured as the positive power supply pin (VDD).

[0057] The third pin (PIN3) is configured as a data output pin (DOUT);

[0058] The fourth pin (PIN4) is configured as the negative power supply pin (GND).

[0059] 2. In one embodiment of the present invention, in the die bonding process of S2, the driver chip 3 and the RGB LED chip 4 are fixed on the pads of the package bracket 1 using a high thermal conductivity insulating adhesive. The pin layout and pad shape of the package bracket 1 are optimized to form a heat dissipation path with low thermal resistance.

[0060] 3. In one embodiment of the present invention, in the wire bonding process of S3, gold wire or copper wire is used for wire bonding. The driver chip 3 integrates a single-wire serial communication interface and a PWM dimming circuit. The independent control of each color chip of the RGB LED by the driver chip 3 is realized through wire bonding.

[0061] 4. In one embodiment of the present invention, the process parameters for the curing step in S5 are: curing time of 1.5 to 3 hours at a temperature of 120°C to 150°C.

[0062] 5. In one embodiment of the present invention, the test sorting step in S6 includes testing the color coordinates, brightness, voltage and communication function of the LED beads to ensure that the color synchronization error is less than ±1% and that 256 levels of grayscale adjustment can be achieved.

[0063] Working Principle: The core technology of the fabrication method described in Example 1 lies in its architecture design that minimizes the pin set and pin function reuse, thus breaking through the pin count limitation of traditional LED chips at the physical level. During fabrication, the driver chip 3 and the RGB LED chip 4 determine their spatial relationship through high-precision die bonding and establish an internal electrical connection network through wire bonding. Specifically, the DIN pin is identified as a power input port by the internal circuit during the power-on initialization phase, providing the start-up voltage to the driver chip 3; during normal operation, it switches to a serial data receiving port. After receiving and decoding the serial data, the driver chip 3 independently modulates the driving current of the three-color LED chips through its internally integrated PWM dimming circuit. Finally, the chip, leads, and electrical connection structure are solidified into a complete miniature light-emitting unit through an integrated packaging process.

[0064] Example 2:

[0065] This embodiment is basically the same as the previous embodiment, except that in the encapsulation molding step of S4, the encapsulating colloid is silicone or epoxy resin doped with scattering particles (such as silicon dioxide or titanium dioxide). The scattering particles are used to make the light emitted by the RGB LED chip 4 mix evenly and expand the light emission angle.

[0066] Working Principle: Based on Example 1, Example 2 further solves the problems of uneven light mixing, color spots, and narrow viewing angles caused by the small size and close arrangement of chips by introducing an encapsulating colloid doped with scattering particles. The scattering particles change the propagation path of light within the encapsulation, causing the light emitted by chips at different locations to superimpose and merge at the microscale, significantly improving the optical quality of a single LED as a display pixel.

[0067] A miniature, highly integrated, RGB LED bead is fabricated using the methods described in Embodiments 1 and 2. The bead has a package size of 1.5mm × 1.5mm × 1.0mm and integrates a driver chip 3 and at least one set of RGB LED chips 4. Power supply, data input, and output functions are achieved through only four exposed pins. This miniature, highly integrated, RGB LED bead is used in miniature display and lighting devices, including: indoor and outdoor micro-pitch displays, indicator and decorative lighting for smart wearable devices such as smart bracelets / watches, automotive dashboard and interior ambient lighting, miniature landscape and decorative lighting, and status indicator lights for IoT terminal devices.

[0068] A miniature display and lighting device includes multiple miniature, highly integrated, multi-colored LED beads. These LED beads are cascaded sequentially via their data output pins (DOUT) and data input pins (DIN) to form a display pixel array. The driver chip 3 inside each LED bead is configured to: upon receiving the cascaded data stream, extract and respond with the data segment corresponding to its own address, while simultaneously forwarding the remaining data stream from its data output pin (DOUT) to the next LED bead. This achieves independent addressing and control of all pixels on a single data path. This serially cascaded pin connection method significantly reduces the wiring complexity of the display's driver circuit, simplifying the traditional multi-line parallel control architecture to a single data link. This significantly reduces the number of printed circuit board layers and wiring area, lowers system power consumption and electromagnetic interference, and greatly improves the scalability and modular assembly efficiency of the pixel array.

[0069] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A method for fabricating micro-sized, highly integrated, colorful LED beads, characterized in that, Includes the following steps: S1: Substrate preparation, providing a miniaturized packaging bracket (1) with four electrical pins (2). S2: Die bonding, fixing the driver chip (3) and at least one set of RGB LED chips (4) to a designated area of ​​the package bracket (1) by die bonding process, the driver chip (3) and the RGB LED chips (4) are integrated into the same package body; S3: Wire bonding, through wire bonding process, establish electrical connections between the driver chip (3) and the RGB LED chip (4), and between the driver chip (3) and the four electrical pins (2); S4: Encapsulation and molding, using an encapsulating colloid with predetermined light transmittance and refractive index to mold and encapsulate the chip assembly with completed wire bonding to form the main body of the lamp bead; S5: Curing, curing the encapsulating colloid; S6: Testing and sorting. The photoelectric performance of the cured LED beads is tested, and the beads are sorted according to the test results to obtain the finished LED beads.

2. The method for manufacturing a micro-sized, highly integrated, multi-colored LED bead according to claim 1, characterized in that, The four electrical pins (2) are configured as a minimal set of pins to enable data signal transmission, power supply and grounding functions.

3. The method for manufacturing a micro-sized, highly integrated, multi-colored LED bead according to claim 2, characterized in that, In the minimized pin set, at least one pin is configured to have multiplexing functions for signal transmission and power transmission.

4. The method for manufacturing a micro-sized, highly integrated, multi-colored LED bead according to claim 1, characterized in that, In the die bonding process of S2, the driver chip (3) and the RGB LED chip (4) are fixed on the pads of the packaging bracket (1) using a high thermal conductivity insulating adhesive.

5. The method for manufacturing a micro-sized, highly integrated, multi-colored LED bead according to claim 1, characterized in that, In the wire bonding process of S3, gold wire or copper wire is used for wire bonding. The driver chip (3) integrates a single-wire serial communication interface and a PWM dimming circuit.

6. The method for manufacturing a micro-sized, highly integrated, multi-colored LED bead according to claim 1, characterized in that, In the encapsulation molding step S4, the encapsulating colloid is silicone or epoxy resin doped with scattering particles; the process parameters for the curing step in S5 are: curing time of 1.5 to 3 hours at a temperature of 120°C to 150°C; the testing and sorting step in S6 includes testing the color coordinates, brightness, voltage and communication function of the LED beads.

7. A micro-sized, highly integrated, multi-colored LED bead prepared by the preparation method according to any one of claims 1-6.

8. The micro-sized, highly integrated, multi-colored LED bead according to claim 7, characterized in that, The package size of the micro-sized, highly integrated, colorful LED lamp bead is 1.5mm × 1.5mm × 1.0mm.

9. The application of the micro-sized, highly integrated, RGB LED beads as described in claim 8 in micro-sized display and lighting devices.

10. A miniature display and lighting device, characterized in that, It includes multiple micro-sized, highly integrated, colorful LED beads as described in claim 7, wherein the multiple micro-sized, highly integrated, colorful LED beads are connected in a serial cascade manner, that is, the serial data output terminal of the previous stage LED bead is electrically connected to the serial data input terminal of the next stage LED bead, so as to form a pixel array that can be serially addressed.

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