WO2015154648A1

WO2015154648A1 - Weldable led substrate

Info

Publication number: WO2015154648A1
Application number: PCT/CN2015/075956
Authority: WO
Inventors: 诸建平; 吴祖通
Original assignee: 浙江聚光科技有限公司
Priority date: 2014-04-08
Filing date: 2015-04-07
Publication date: 2015-10-15
Also published as: CN103900044A

Abstract

A weldable LED substrate comprises an LED light source (1) and a substrate (3). The surface of the substrate (3) is provided with a metal layer (2) in a thermal spraying mode, and the LED light source (1) is welded to the metal layer (2). After the LED light source (1) is welded, heat can be directly transferred to the metal layer (2) through a supporting frame and then rapidly transferred from the metal layer (2) to a heat radiator to be dissipated, so that heat resistance is reduced to the maximum extent, the heat conduction efficiency is improved, and light attenuation of the LED light source is reduced.

Description

Solderable LED substrate

Technical field

The invention relates to a novel LED substrate, in particular to a substrate on which a surface can directly solder an LED light source and a manufacturing process thereof.

Background technique

As the internationally recognized fourth-generation green lighting source, light-emitting diode (LED) has the unique advantages of energy saving, environmental protection, no radiation, long service life, fast response, and impact resistance. With the continuous improvement of LED performance, its application fields continue to increase. Expansion, the application power of the light source is also constantly increasing, and the resulting heat generation is also greatly increased. Since the heat generated by the LED, especially the power LED light source, or the multi-light source is applied at the same time, the heat is concentrated and continuously generates heat, so there is a strict requirement for the heat dissipation of the light source, which not only directly affects the light attenuation of the LED light source, but also relates to The overall stability and service life of LED applications (lamps).

At present, for the heat treatment of the LED light source, the LED light source is generally fixed on the LED aluminum substrate by mechanical contact, and after forming the light source module, it is fixed on the heat sink, and the heat dissipation fin of the heat sink is used for heat dissipation. . For example, the high-power LED road lighting patent patent application number is 200710042990.5, including at least one high-power LED lamp head and a heat sink, wherein the high-power LED lamp head is fixed on the heat sink, and the high-power LED lamp head includes a lamp base and an aluminum substrate. a lens, the upper surface of the base of the lamp holder is provided with a groove, and the aluminum substrate is bound with a plurality of high-power LED chips with a power of 1W or 3W, and the high-power LED lamp head has a power of 20W to 40W, and the aluminum substrate is fixed in the concave Inside the slot, the lens is fixed above the aluminum substrate.

The patent fixes the LED light source on the aluminum substrate, and on the one hand, can make electrical circuit distribution on the aluminum substrate, thereby directly connecting the respective light sources to form a light source module, which has high electrical performance and stability; And when it is produced, it has the advantages of simple structure, high reliability, and easy assembly and production. However, this technology also has a large disadvantage in the heat dissipation performance of the LED light source. On the one hand, the LED light source is fixed by mechanical means, and the bonding surface cannot be completely flat. Generally, the thermal paste coating method is needed to fill the gap, but the thermal conductivity of the thermal paste is small, and the thermal resistance is still relatively good compared with the metal welding. On the other hand, the heat of the LED light source is first transmitted to the aluminum substrate through the bracket, and then the heat is transferred to the heat sink by the aluminum substrate, and the heat needs to be transferred twice, and the LED light source is directly transmitted to the heat sink with respect to the primary heat transfer. The heat dissipation fins of the heat sink directly dissipate heat, and the heat resistance is still large, and the heat transfer efficiency is poor, which may result in an unsatisfactory heat dissipation effect.

Summary of the invention

The invention is directed to the above-mentioned deficiencies, and the disadvantage that the existing aluminum alloy heat sink is difficult to directly solder the LED light source, and provides a novel LED substrate with simple structure and good heat transfer capability and a manufacturing process thereof.

In order to achieve the above object, the invention adopts the following measures: a solderable LED substrate comprising an LED light source and a substrate, wherein the surface of the substrate is thermally sprayed with a metal layer, and the LED light source is soldered on the metal layer.

The substrate may be a bottom of the outer casing, a flat plate or a heat sink with fins.

The thermal spraying process uses arc spraying or plasma spraying.

The metal layer is a solderable material and comprises one or more of copper, lead, tin, and silver.

The welding method uses one or more of solder paste welding, heating stage, reflow soldering, and ultrasonic welding.

The metal layer has a thickness of 0.05 to 0.5 mm.

A manufacturing process of a solderable LED substrate, characterized in that first, a metal layer is thermally sprayed on a surface of the substrate, and then the LED light source is fixed on the metal layer by a soldering process.

The thermal spraying is performed by an arc spraying process or a plasma spraying process.

The welding process uses one or more of solder paste soldering, heating, reflow, and ultrasonic welding.

The beneficial effects of the invention:

In terms of thinking mode, this patent completely subverts the traditional aluminum substrate welding light source, and then fixes the existing technology of the heat sink, directly soldering the LED light source directly to the heat sink, although the application principle and structure of the technology are easy to understand. However, from the application fields in the middle and lower reaches of the LED industry, the transformation of LED light source transmission technology will be realized, and the promotion and popularization of LED semiconductor lighting will be promoted, which has great social and economic benefits.

In the patented technology, the direct connection of the LED light source is fixed on the metal layer of the heat sink, which not only reduces the thermal conduction intermediate transition of the aluminum substrate, but also reduces the mechanical transition of the aluminum substrate. After the light source is welded, the strength is higher and the stability is better. The metal layer material generally adopts a high thermal conductivity weldable metal such as copper. After the LED light source is welded, it can be directly transmitted to the metal layer through the bracket, and then the metal layer quickly transfers the heat to the metal layer. The heat sink dissipates heat to minimize thermal resistance, improve thermal conductivity, and reduce light attenuation of the LED source.

In the production process, on the one hand, the metal layer is thermally bonded to the surface of the substrate by means of thermal spraying, which not only has the technical advantages of high bonding strength, easy to fall off under high temperature, but also has simple thermal spraying equipment, no special requirements for spraying metal materials, and can be artificial or Automatic operation, high production efficiency and good yield, not affected by external conditions. On the other hand, in the welding method of the LED light source, the existing mature welding process such as reflow soldering is adopted, and the batch welding of the light source on the metal layer is easily realized. Therefore, according to the patented technology, the technology can be greatly improved not only in the conduction heat performance, but also in the production process, the production efficiency is high, and the overall cost is low.

DRAWINGS

Figure 1 is a schematic view of a preferred embodiment of the present invention;

Figure 2 is a schematic cross-sectional view showing a preferred embodiment of the present invention;

Figure 3 is a schematic view of another preferred embodiment of the present invention;

Figure 4 is a schematic cross-sectional view showing another preferred embodiment of the present invention.

detailed description

The invention is further described below in conjunction with the drawings and specific embodiments, but is not to be construed as limiting.

Example 1

As shown in FIG. 1 and FIG. 2, the embodiment is mainly composed of an LED light source 1, a metal layer 2, a substrate 3, a PCB board 4 and the like. Wherein, the surface of the substrate 3 is thermally sprayed with the metal layer 2, the surface of the metal layer 2 and the substrate 3 is mounted with the PCB board 4, and a plurality of openings are arranged in the middle of the PCB board 4, the aperture is slightly larger than the size of the bracket of the LED light source 1, LED The light source 1 is mounted in the opening of the PCB board 4 and soldered on the metal layer 2. The pins of the LED light source 1 are soldered on the PCB board 4 to form a connection with the circuit distribution on the PCB board 4.

During the spraying process of the metal layer 2, for the selection of the thermal spraying position of the surface of the substrate 3, local fixed-point spraying or full spraying may be adopted. All thermal spraying is used. On the one hand, it is not necessary to make auxiliary parts such as jigs, and it can be directly sprayed. On the other hand, after welding the LED light source 1, since the metal layer 2 to be sprayed has a high thermal conductivity, a common copper is taken as an example. The thermal conductivity can reach about 400 W/mK, and all of them are sprayed on the light source mounting surface of the substrate 3, which is more favorable for heat transfer. Using local fixed-point thermal spraying, Relative to all sprays, you need to make professional fixtures and control the accuracy of the spray. In the embodiment, the substrate 3 adopts a common aluminum alloy heat sink. Since the aluminum alloy material also has a high thermal conductivity, the metal layer 2 after spraying can be quickly transmitted through the aluminum alloy heat sink at about 230 W/mK. heat. Therefore, this embodiment preferentially adopts the method of local fixed point spraying. After considering the performance and cost factors, the metal layer 2 adopts a linear strip-like distribution whose width should be slightly larger or larger than the bottom of the holder of the LED light source 1, and a plurality of linear strip-shaped metal layers 2 are sprayed on the surface of the substrate 3. In the actual application process, the spraying position of the metal layer 2 can be continuously adjusted as needed, such as using various shapes, regularly or irregularly distributed on the surface of the substrate 3.

In the thermal spraying method of the metal layer 2, arc spraying, plasma spraying or the like can be employed. Among them, the plasma coating technology uses a plasma arc driven by a direct current as a heat source to heat ceramics, alloys, metals and the like into a molten or semi-molten state, and sprays at a high speed onto the surface of the pretreated workpiece to form a firm surface. Layer method. It has the following characteristics: 1. Ultra-high temperature type, easy to spray high-melting material; 2. High speed of spraying particles, dense coating and high bonding strength; 3. Use inert gas for working gas, spraying material is not easy Oxidation, etc.

In comparison, arc spraying uses an arc that is burned between two continuously fed wires to melt the metal, atomizes the molten metal with a high velocity gas stream, and accelerates the atomized metal particles to spray them onto the workpiece. The technique of forming a coating. Before the arc spraying, pre-pretreatment, that is, sandblasting, is required to achieve a certain bonding strength to prevent the sprayed layer from falling.

Arc spraying improves the flying speed and atomization quality of the molten particles, reduces the void ratio of the coating, and increases the bonding strength between the coating and the substrate. It has the following technical advantages: simple preparation, high spraying efficiency, and convenient replacement of the spraying materials. High safety, low cost and high coating quality. Therefore, the present embodiment preferably employs arc spraying to thermally spray the metal layer 2 on the surface of the substrate 3.

The metal layer 2 is a solderable material, and mainly contains one or more of copper, lead, tin, and silver. On the one hand, the above metal materials have good solderability and are easy to be processed and sprayed; on the other hand, the above metal materials have high thermal conductivity, and after welding the LED light source 1, the thermal resistance is low and the thermal conductivity is good. In the comprehensive consideration of performance and cost, it is preferred to use a copper-containing material for thermal spraying.

The thickness of the sprayed metal layer is generally 0.05 to 0.5 mm. If the thickness of the spray is too thin, it tends to cause insufficient adhesion of the metal layer, causing the metal layer to fall off; if the spray is too thick, it tends to cause an increase in material and processing costs. Therefore, by comparison test, the thickness of the metal is preferably 0.1 mm.

When the LED light source 1 is soldered on the surface of the metal layer 2, it is generally solder paste soldered, or reflow soldered, or super Sonic welding. In small batch test or sample preparation, traditional solder paste can be used for manual welding to reduce the use of professional equipment; in the process of mass production, reflow or ultrasonic welding can be used, due to the requirements of ultrasonic welding for welding materials. It is relatively high and requires ultrasonic welding equipment, so it is generally less used. The heating stage and the reflow soldering process have been widely applied in the field of electronic applications. Considering mass production efficiency and soldering quality, it is preferable to solder the LED light source 1 to the metal layer 2 by means of a heating stage or reflow soldering.

The PCB board 4 is fixed above the substrate 3 and the metal layer 2, preferably an insulating, temperature-resistant glass fiber board. In the implementation process, it is generally mounted on the substrate 3 in the form of a whole piece. On the one hand, it is convenient to provide a circuit distribution on the surface, and after the pins of the two ends of the LED light source 1 are welded, an electrical connection is formed; on the other hand, the installation process can be ensured. The positional accuracy in the middle, especially the accuracy of the opening position, will directly affect the welding position of the LED light source 1, which is convenient for batch installation and production, and also ensures the overall aesthetics of the PCB board 4 after installation.

The substrate 3 may be a bottom of the casing, a flat plate or a heat sink with fins, and the surface of the component having a heat dissipating function may be considered as the substrate 3. If the luminaire housing has a heat dissipation function, such as an LED ceiling lamp, the substrate 3 may be the bottom of the luminaire housing, and the LED light source 1 may be directly soldered to the bottom of the housing; if the number of LED light sources 1 is small or the power is small, and the space is limited Generally, a flat (metal) plate is used as the substrate 3; if the total power of the LED light source is large, it is applied to a large-sized lamp, and the space is large, which generally uses a heat sink with fins. In this embodiment, the substrate 3 is provided with a heat sink with heat dissipation fins, so that the heat generated by the LED light source 1 can be quickly transmitted to the heat dissipation fins to achieve convection heat dissipation with air.

As the material of the substrate 3, a metal or alloy material which is highly thermally conductive and easily formed such as aluminum, copper or aluminum alloy can be used. Considering the comprehensive factors of cost and performance, it is preferably made of aluminum alloy material, and is formed by one extrusion process and then processed according to production needs.

Example 2

3 and 4, the preferred embodiment is mainly composed of an LED light source 1, a metal layer 2, a substrate 3, and the like. The substrate 3 adopts an aluminum alloy heat sink similar to a sunflower flower structure, and the central portion is a solid cylinder, and the heat dissipation fins are radially distributed around the cylinder. A metal layer 2 is thermally sprayed on the cylindrical plane on the substrate 3, and the integrated packaged LED light source 1 is soldered to the surface of the metal layer 2.

As the main component of heat dissipation, the substrate 3 can be changed according to actual application requirements, and can be considered The surface of the component that serves to dissipate heat can be used as the substrate 3 to thermally spray the metal layer 2 on the surface. The substrate 3 in the present embodiment adopts a heat sink similar to a sunflower flower structure. On the one hand, it has a wide application field, and can be used in small indoor lamps such as LED downlights and LED ceiling lamps; on the other hand, its thermal conductivity is high, and the heat dissipation area is high. Large, good overall heat dissipation performance, production by extrusion process, low cost, suitable for batch scale applications.

The LED light source 1 is used as a light-emitting device, and in practical applications, it can be selected according to different division criteria such as the power size and the number of chips in the light source. As in the present embodiment, the welding area of the LED light source 1 is limited, it is difficult to solder more light sources, and the heat dissipation efficiency of the substrate 3 is high. Therefore, it is preferable to directly solder the high-power LED light source 1 on the metal layer 2 by using an integrated package.

After the LED light source 1 is soldered on the metal layer 2, the circuit board of the LED light source 1 can be connected to the driving power source by providing a circuit board beside the light source or directly adopting a wire.

The embodiments described above are only preferred embodiments of the present invention, and the usual changes and substitutions made by those skilled in the art within the scope of the technical solutions are included in the scope of the present invention.

Claims

A solderable LED substrate comprising an LED light source and a substrate, wherein the surface of the substrate is thermally sprayed with a metal layer, and the LED light source is soldered on the metal layer.
A solderable LED substrate according to claim 1, wherein the substrate is a bottom of a case, a flat plate or a heat sink with heat sink fins.
A solderable LED substrate according to claim 1 or 2, wherein said thermal spraying is by arc spraying or plasma spraying.
The solderable LED substrate according to claim 3, wherein the metal layer is a solderable material and comprises one or more of copper, lead, tin, and silver.
The solderable LED substrate according to claim 3, wherein the soldering method is one or more of solder paste soldering, heating, reflow soldering, and ultrasonic soldering.
A solderable LED substrate according to claim 3, wherein said metal layer has a thickness of 0.05 to 0.5 mm.
A manufacturing process of a solderable LED substrate, characterized in that first, a metal layer is thermally sprayed on a surface of the substrate, and then the LED light source is fixed on the metal layer by a soldering process.
The process for fabricating a solderable LED substrate according to claim 7, wherein the thermal spraying is performed by an arc spraying process or a plasma spraying process.
The process for fabricating a solderable LED substrate according to claim 8, wherein the soldering process uses one or more of solder paste soldering, heating, reflow soldering, and ultrasonic soldering.