WO2014169819A1

WO2014169819A1 - Led multi-cup integrated cob light source and encapsulation method therefor

Info

Publication number: WO2014169819A1
Application number: PCT/CN2014/075476
Authority: WO
Inventors: 胡琨
Original assignee: Hu Kun
Priority date: 2013-04-16
Filing date: 2014-04-16
Publication date: 2014-10-23
Also published as: CN103972223A; CN103972223B; CN103258819A

Abstract

An LED multi-cup integrated COB light source and encapsulation method therefor. The method comprises: performing silver precipitation on a PCB substrate; fixing multiple LED chips separately onto the PCB substrate by means of viscose, and electrically connecting the LED chips to the PCB substrate by means of wire-bonding; arranging one optic cup for each LED chip, and encapsulating the optic cup and the LED chip together on the PCT substrate. The solution fully utilizes the PCB substrate that has been silver precipitated, such that the silver plated layer does not require matching parameters for power, pressure, and temperature during the process of die bonding and wire bonding, thereby reducing cold solder joints and false solder points between the LED chips and bonding wires and enhancing the COB light source encapsulation success rate. Optic cups and LED chips are encapsulated together, thereby fully utilizing the optic processing of the optic cups and enhancing the light emitting efficiency of the COB light sources.

Description

LED multi-cup integrated integrated COB light source and packaging method thereof

Technical field

The invention relates to the technical field of LED packaging, in particular to an LED multi-cup integrated integrated COB light source and a packaging method thereof.

Background technique

COB is Chip On The English abbreviation of Board (on-board chip direct mounting) is a kind of packaging technology that directly bonds the LED chip to the PCB board through chip solid crystal glue, and then electrically interconnects the chip and the PCB board through wire bonding. The package structure of the bracket has the advantages of low cost and high reliability, but the prior art COB package is packaged by using a conventional PCB made by a silver plating process, resulting in a silver plating layer on the PCB surface in the solid crystal and the wire. Process, power, pressure and temperature have no matching parameters Therefore, the welding wire has a virtual welding and a false welding, which is prone to the flashing or dead light phenomenon of the light source; in addition, although the COB light source has a good heat dissipation function, the copper foil under the substrate can only be energized well, but cannot Do a good optical treatment, the light output rate is not high.

How to solve the problem of virtual welding and false welding, improve the packaging yield, and improve the light extraction rate of COB light source is a problem to be solved.

Summary of the invention

The main object of the present invention is to provide an LED multi-cup integrated integrated COB packaging method capable of reducing the light-emitting and false-welding ratio of an LED chip and improving the light-emitting rate of the COB light source, and the LED multi-cup integration formed by the above method Integrated COB light source.

In order to solve the above object, the first technical solution proposed by the embodiment of the present invention is:

An LED multi-cup integrated integrated COB packaging method, comprising:

Performing a silver plating process on the PCB substrate;

Disposing a plurality of LED chips on the PCB substrate, and electrically connecting the LED chip and the PCB substrate by wire bonding;

An optical cup is disposed corresponding to each of the LED chips, and the optical cup and the LED chip are integrally packaged on the PCB substrate, wherein the reflective film is plated by magnetron sputtering in the optical cup.

Further, the LED chip is a small power chip, and the spacing between the small power chips is greater than 5 mm.

Further, the step of providing an optical cup corresponding to each LED chip and integrally packaging the optical cup and the LED chip on the PCB substrate comprises:

Each optical cup is designed to have a multi-point integrated surface illumination design.

Further, the step of providing an optical cup corresponding to each LED chip and integrally packaging the optical cup and the LED chip on the PCB substrate includes

Fill the optical cup with a full light guide.

Further, before the step of fixing the plurality of LED chips by the adhesive to the PCB substrate and electrically connecting the LED chip to the PCB substrate by wire bonding, the method includes:

A groove that is fully or partially embedded in the optical cup is etched on the PCB substrate at a position corresponding to the LED chip.

The embodiment of the invention further provides an LED multi-cup integrated integrated COB light source, comprising a PCB substrate processed by a silver plating process, an LED chip and an optical cup.

Disposing the LED chip on the PCB substrate, and electrically connecting the LED chip and the PCB substrate by wire bonding;

One optical cup is disposed corresponding to each LED chip, and the optical cup and the LED chip are integrally packaged on the PCB substrate, wherein a reflective film coated by magnetron sputtering is disposed in the optical cup.

Further, the optical cup is disposed on the PCB substrate through a light-emitting design of a multi-point integrated surface.

Further, the optical cup is filled with a light guide glue.

Further, the position of the corresponding LED chip on the PCB substrate is etched to fit all or part of the recessed surface of the optical cup.

The invention has the beneficial effects that the PCB substrate processed by the immersion silver process is fully utilized, and the immersion silver process is a process of etching silver after the substrate is first etched, so that the silver plating layer is in the process of solid crystal and wire bonding, and the power, pressure and temperature are not The matching parameters are needed, thereby reducing the occurrence of virtual soldering and false soldering between the LED chip and the bonding wire, improving the packaging yield of the COB light source, and simultaneously adopting the form of the optical cup and the LED chip in one package, making full use of the optical cup. The optical treatment effect improves the light extraction efficiency of the COB light source.

DRAWINGS

1 is a flow chart of an LED multi-cup integrated integrated COB packaging method according to an embodiment of the invention;

2 is a schematic diagram of light exiting of each light cup in an LED multi-cup integrated integrated COB packaging method according to an embodiment of the invention;

FIG. 3 is a schematic diagram showing the arrangement of a light cup in an LED multi-cup integrated integrated COB light source according to an embodiment of the invention.

The implementation, functional features, and advantages of the present invention will be further described in conjunction with the embodiments.

detailed description

It is understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Referring to FIG. 1 , an embodiment of the present invention provides an LED multi-cup integrated integrated COB packaging method, including:

Step S1, performing a silver immersion process on the PCB substrate 10; the difference between the immersion silver process and the silver plating process is that the silver plating process is performed by plating a layer of silver on the circuit board after development, and then performing etching; After development, the pattern is electroplated with copper, tinned, relinded, etched, and silver is deposited in the pads and holes after the solder mask is printed. The silver plating process has silver in the entire line and via holes, so it is easy to cause the occurrence of soldering and false soldering. The silver plating process only has silver on the pads and holes, so the PCB substrate 10 after the silver processing is processed. In the process of solid crystal and wire bonding, the power, pressure and temperature do not need matching parameters, thereby reducing the occurrence of virtual welding and false welding between the LED chip 40 and the bonding wire, and improving the packaging yield of the COB light source;

Step S2, the plurality of LED chips 40 are dispersed and fixed on the PCB substrate 10 by adhesive, and the LED chip 40 is electrically connected to the PCB substrate 10 by wire bonding; of course, the general expansion is included before this step. The steps of a general COB package;

In step S3, an optical cup 30 is disposed corresponding to each LED chip 40, and the optical cup 30 and the LED chip 40 are integrally packaged on the PCB substrate 10. The optical cup 30 can function as a light collecting function, and the LED chip 40 can be used. The illuminating light is gathered to improve the light-emitting efficiency of the COB light source, and the optical cup 30 and the LED chip 40 are integrally packaged on the PCB substrate 10, so that the optical cup 30 can be stably installed and the installation is more convenient and quick.

In an embodiment of the invention, the optical cup 30 is coated with a reflective film by magnetron sputtering. The magnetron sputtering coating can effectively improve the reflectivity of the reflective film, and the material and the chip can be directly contacted, so that the heat dissipation is only One layer can be directly transmitted to the PCB substrate 10, and the substrate is connected to the outer casing, and the heat dissipation efficiency is high.

In an embodiment of the invention, the LED chip 40 is a small power chip, and the spacing between the small power chips is greater than 5 mm. The so-called low power chip mainly includes 7*8 mil and 9*9. Mil, white light, red yellow light chip such as mil, 9*11 mil, 10*10 mil, 12*12mil. research shows, The LED chip 40 emits light inside the chip. To allow more light to be released, there must be a lot of light exits, so that the efficiency of light can be improved, and the efficiency of low-power chip packaging is about 15% of the efficiency of high-power chip packaging. In the above, the multi-cup integrated integrated COB packaging technology of the present invention can divide a high-power chip into more than ten small-power chips and form them in a one-time package according to optical distribution, thereby improving the light-emitting efficiency of 15%, and not Increasing the physical cost and labor cost, and the distributed multi-point package can increase the single-point heat dissipation area, so that the heat dissipation effect is better, and experiments show that the low power chip spacing of 5mm or more can reduce the temperature of the PCB substrate by 105 ° C, and the temperature of the PCB substrate 10 is lowered. Then, the luminescence attenuation of the LED chip 40 is lowered, the luminous efficiency of the LED chip 40 can be greatly improved, and the service life of the LED chip 40 can be prolonged.

In an embodiment of the present invention, when the LED chip 40 is driven by the same voltage, the LED chip 40 emits the same wavelength and the same brightness, that is, before the LED chip 40 is packaged, the LED chip 40 is required. The selection and testing are carried out to obtain the same illuminating color and illuminating brightness when driven by the same voltage, so that the luminescent aberration of the COB source after packaging can be avoided.

In an embodiment of the invention, an optical lens is disposed on the optical cup 30, and the light of the LED chip 40 is emitted through the lens, so that the light output of the LED chip 40 can be further adjusted to achieve a desired light exit angle and the like.

In an embodiment of the present invention, the optical glass 30 is disposed on each of the LED chips 40, and the optical glass 30 and the LED chip 40 are integrally packaged on the PCB substrate 10. In step S2, the method includes: The optical cup performs the illumination design of the multi-point integrated surface. The multi-point integrated surface illumination design can effectively avoid glare caused by excessive local light caused by the small distance between the light-emitting points, or the distance between the light-emitting points is too large, and the light is insufficient to complement each other. The zebra pattern, as shown in FIG. 2-A, is a light-emitting effect diagram of the four LED chips 40 after the optical cup 30 is disposed, wherein the shaded portion is a coincident portion of each light source after the light is emitted, and only the adjacent light source can be obtained. The overlapping part avoids the overlapping portions of the light emitted by the plurality of light-emitting points, generating a spot, and at the same time avoiding the light source from leaking a certain area. Similarly, Figure 2-B and Figure 2-C are five. Luminous design of the luminous point and three luminous points.

In an embodiment of the invention, the wire bonding is performed by thermosonic bonding or ultrasonic bonding at normal temperature, the technology is mature, and the welding is firm, and the thermosonic bonding is performed by gold wire ball bonding, and the ultrasonic key at normal temperature. The joint is welded by an aluminum file.

In an embodiment of the present invention, the step S2 of disposing the plurality of LED chips 40 by the adhesive is fixed on the PCB substrate 10, and the LED chip 40 is electrically connected to the PCB substrate 10 by wire bonding. The PCB substrate 10 is cleaned, and the adhesive is dropped on a position where the LED chip 40 of the PCB substrate 10 is to be fixed. The cleaned PCB substrate 10 still has oily or oxide layer and other unclean parts. It can be used to test the position or test the needle position. The wiped PCB board should be cleaned with a brush or blown with an air gun to flow into the next process. For products with strict antistatic properties, use an ion blower. The purpose of the cleaning is to clean the dust and oil on the PCB substrate 10 to improve the bonding quality; and the adhesive is dropped on the PCB substrate 10 where the LED chip 40 is to be fixed, and the adhesive is dropped. The purpose is to prevent the LED chip 40 from falling off during the transfer and bonding process. Usually, the needle transfer and pressure injection methods are used. The needle transfer method is: using a needle to take a small amount of adhesive from the container and applying it on the PCB substrate. 10, this is a very rapid dispensing method; the pressure injection method is: the glue is put into the syringe, and a certain pressure is applied to squeeze out the glue. The size of the glue point is determined by the size of the nozzle of the syringe and the pressing time and The size of the pressure is determined.

As shown in FIG. 3, in an embodiment of the present invention, an optical cup 30 is disposed corresponding to each LED chip 40, and the optical cup 30 and the LED chip 40 are integrally packaged on the PCB substrate 10. The optical glass 30 is mounted on the PCB substrate 10, and the optical glass 30 is filled in the optical glass 30. The optical glass 30 is fixed on the PCB substrate 10, and the optical glass 30 is filled. The light guiding glue 40 enables the LED chip 40 and the optical cup 30 to be relatively fixedly connected, greatly improving the seismic performance of the COB package light source, improving the use efficiency and service life of the COB package light source, and improving the light extraction rate of the LED chip 40 because The light guiding glue 40 forms a columnar body in the optical cup 30, and some light is totally reflected in the light guiding glue 40 of the columnar body, so that the light exiting angle is small and the light emitting efficiency is high.

As shown in FIG. 3, in an embodiment of the present invention, the plurality of LED chips 40 are dispersed and fixed on the PCB substrate 10 by adhesive, and the LED chip 40 and the PCB substrate 10 are electrically connected by wire bonding. Before the step S2 of the connection, the embossing of the groove of the optical cup 30 is fully or partially embedded on the PCB substrate 10 corresponding to the position of the LED chip 40. The design of the groove is convenient for alignment during the installation process of the optical cup 30, and The adhesive between the optical cup 30 and the sidewall of the groove can be filled, which greatly improves the stability of the optical cup 30, and can also reduce the overall thickness of the COB light source and reduce the volume.

In the embodiment of the present invention, an LED multi-cup integrated integrated COB light source is further provided, including a PCB substrate 10 processed by a silver plating process, an LED chip 20 and an optical cup 30, wherein the LED chip 20 is dispersedly disposed on the PCB. On the substrate 10, the LED chip 20 is electrically connected to the PCB substrate 10 by wire bonding; one optical cup 30 is disposed corresponding to each LED chip 20, and the optical cup 30 and the LED chip 20 are integrally packaged on the PCB substrate. In 10, a reflective film coated by magnetron sputtering is disposed in the optical cup 30.

The difference between the silver-plating process and the silver-plating process is that the silver plating process is to deposit a layer of silver on the circuit board after development, and then perform etching; and the silver-plating process is to develop a pattern of copper, tin, and film after development. Etching, sinking silver in the pads and holes after the solder mask is printed The silver plating process has silver in the entire line and via holes, so it is easy to cause the occurrence of soldering and false soldering. The silver plating process only has silver on the pads and holes, so the PCB substrate 10 after the silver processing is processed. In the process of solid crystal and wire bonding, the parameters of power, pressure and temperature do not need to be matched, thereby reducing the occurrence of virtual welding and false welding between the LED chip 20 and the bonding wire, and improving the packaging yield of the COB light source, so The LED multi-cup integrated integrated COB light source of the invention is more stable, and the electrical connection relationship between the electric appliances is more stable, and the quality of the de-energization is improved. The optical cup 30 can function as a condensing light, and the illuminating light of the LED chip 20 can be gathered to improve the light-emitting efficiency of the COB light source. The optical cup 30 and the LED chip 20 are integrally packaged on the PCB substrate 10 to improve the optical efficiency. The cup 30 is stable and easy to install. The optical cup 3030 is coated with a reflective film by magnetron sputtering. The magnetron sputtering coating can effectively improve the reflectivity of the reflective film, and can directly contact the material and the chip, so that only one layer of heat can be directly transmitted to the PCB substrate. On the 10th, the substrate is connected to the outer casing, and the heat dissipation efficiency is high.

In an embodiment of the invention, the LED chip 20 is a small power chip, and the spacing between the small power chips is greater than 5 mm. The spacing between small power chips is greater than 5mm, so-called low-power chips mainly include 7*8mil , 9 * 9 mil, 9 * 11 mil, 10 * 10 mil, 12 * 12mil and other blue and white light, red and yellow light chips. research shows, The LED chip 20 emits light inside the chip. To allow more light to be released, there must be a lot of light exits, so that the efficiency of light can be improved, and the efficiency of low-power chip packaging is about 15% of the efficiency of high-power chip packaging. In the above, the multi-cup integrated integrated COB packaging technology of the present invention can divide a high-power chip into more than ten small-power chips and form them in a one-time package according to optical distribution, thereby improving the light-emitting efficiency of 15%, and not Increasing the physical cost and labor cost, and the distributed multi-point package can increase the single-point heat dissipation area, so that the heat dissipation effect is better, and experiments show that the low power chip spacing of 5mm or more can reduce the temperature of the PCB substrate by 105 ° C, and the temperature of the PCB substrate 10 is lowered. Then, the luminescence attenuation of the LED chip 20 is lowered, the luminous efficiency of the LED chip 20 can be greatly improved, and the service life of the LED chip 20 can be prolonged.

In an embodiment of the present invention, the optical cup 30 is disposed on the PCB substrate 10 through a multi-point integrated surface illumination design, and the multi-point integrated surface illumination design can effectively prevent local light from being formed due to too small a spacing of the light-emitting points. Excessively causing glare, or the distance between the light-emitting points is too large, and the light is insufficient to complement each other to form a zebra pattern. As shown in FIG. 2-A, the light-emitting effect of the four LED chips 20 after the optical cup 30 is set, wherein the shaded portion is After the light is separated, the overlapping portions of the light sources can obtain overlapping portions of only the adjacent light sources, avoiding the overlapping portions of the light emitted by the plurality of light-emitting points, generating a spot, and at the same time avoiding the light source from leaking out. Region, the same reason, Figure 2-B and Figure 2-C are the illumination design of five luminous points and three luminous points, respectively.

In an embodiment of the present invention, as shown in FIG. 3, the optical cup 30 is filled with a light guide glue 40, and the arrangement of the light guide glue 40 can improve the mounting stability of the LED chip 20. The optical cup 30 is fixed on the PCB substrate 10. The LED chip 20 is soldered on the PCB substrate 10, and then the optical cup 30 is filled with the light guide glue 40, so that the LED chip 20 and the optical cup 30 are relatively connected and fixed, thereby greatly improving the seismic performance of the COB package light source and improving the COB package light source. The use efficiency and the service life can simultaneously increase the light extraction rate of the LED chip 20, because the light guide glue 40 forms a columnar body in the optical cup 30, and some light is totally reflected in the light guide glue 40 of the column body, thereby making the light The exit angle is small and the light extraction efficiency is high.

In an embodiment of the present invention, as shown in FIG. 3, the position of the corresponding LED chip 20 on the PCB substrate 10 is etched to fit all or part of the recessed surface of the optical cup 30, and the design of the groove is installed in the optical cup 30. The process is convenient for alignment, and the optical cup 30 and the sidewall of the groove can be filled with glue, which greatly improves the stability of the optical cup 30, and can also reduce the overall thickness of the COB light source and reduce the volume.

The above is only the preferred embodiment of the present invention, and is not intended to limit the scope of the invention, and the equivalent structure or equivalent process transformations made by the description of the invention and the drawings are directly or indirectly applied to other related The technical field is equally included in the scope of patent protection of the present invention.

Claims

An LED multi-cup integrated integrated COB packaging method, comprising:

Performing a silver plating process on the PCB substrate;

Disposing a plurality of LED chips on the PCB substrate, and electrically connecting the LED chip and the PCB substrate by wire bonding;

An optical cup is disposed corresponding to each of the LED chips, and the optical cup and the LED chip are integrally packaged on the PCB substrate, wherein the reflective film is plated by magnetron sputtering in the optical cup.
The LED multi-cup integrated integrated COB packaging method according to claim 1, wherein the LED chip is a small power chip, and the spacing between the small power chips is greater than 5 mm.
The LED multi-cup integrated integrated COB packaging method according to claim 1, wherein the step of providing an optical cup corresponding to each LED chip and integrally packaging the optical cup and the LED chip on the PCB substrate Including:

Each optical cup is designed to have a multi-point integrated surface illumination design.
The LED multi-cup integrated integrated COB packaging method according to any one of claims 1 to 3, wherein the optical chip is disposed corresponding to each LED chip, and the optical cup and the LED chip are integrally packaged in the same. In the steps on the PCB substrate, including

Fill the optical cup with a full light guide.
The LED multi-cup integrated integrated COB packaging method according to any one of claims 1 to 3, wherein the plurality of LED chips are dispersed and fixed on the PCB substrate by an adhesive, and passed through leads Before the step of electrically connecting the LED chip to the PCB substrate, the method includes:

A groove that is fully or partially embedded in the optical cup is etched on the PCB substrate at a position corresponding to the LED chip.
An LED multi-cup integrated integrated COB light source, characterized in that comprising a sinking silver processing PCB substrate, an LED chip and an optical cup,

Disposing the LED chip on the PCB substrate, and electrically connecting the LED chip and the PCB substrate by wire bonding;

One optical cup is disposed corresponding to each LED chip, and the optical cup and the LED chip are integrally packaged on the PCB substrate, wherein a reflective film coated by magnetron sputtering is disposed in the optical cup.
The LED multi-cup integrated integrated COB light source according to claim 6, wherein the LED chip is a small power chip, and the spacing between the small power chips is greater than 5 mm.
The LED multi-cup integrated integrated COB light source according to claim 6, wherein the optical cup is disposed on the PCB substrate through a light-emitting design of a multi-point integrated surface.
The LED multi-cup integrated integrated COB light source according to any one of claims 6-8, wherein the optical cup is filled with a light guiding glue.
The LED multi-cup integrated integrated COB light source according to any one of claims 6-8, wherein the position of the corresponding LED chip on the PCB substrate is etched to fit all or part of the recessed groove of the optical cup.
An LED multi-cup integrated integrated COB light source, characterized in that comprising a sinking silver processing PCB substrate, an LED chip and an optical cup,

Disposing the LED chip on the PCB substrate, and electrically connecting the LED chip and the PCB substrate by wire bonding;

One optical cup is disposed corresponding to each LED chip, and the optical cup and the LED chip are integrally packaged on the PCB substrate, wherein the optical cup is provided with a reflective film coated by magnetron sputtering; The LED chip is a small power chip, and the spacing between the small power chips is greater than 5 mm;

The optical cup is disposed on the PCB substrate through a light-emitting design of a multi-point integrated surface; the position of the corresponding LED chip on the PCB substrate is etched to fit all or part of the recessed surface of the optical cup.