LED heat dissipation technology

- Aug 15, 2018-

LED heat dissipation technology

    We describe physical phenomena - objects generate heat during motion. Similarly, heat is generated during operation of the lamp, so how to protect the normal operation of the lamp is referred to as heat dissipation.

    Heat dissipation means that the heat of the heat source LED light source is naturally radiated into the air through the heat sink. The heat dissipation effect is proportional to the size of the heat sink, but the effect is naturally greatly reduced due to the natural heat dissipation, and is often used in those spaces.Such as:

Aluminum radiator

    Aluminum radiators are the most common radiators in the early days. The manufacturing process is simple and the cost is low. 

    In order to increase the heat dissipation area of the fins, the most common processing method for pure aluminum radiators is aluminum extrusion technology, and the main indicator for evaluating a pure aluminum radiator is the thickness of the radiator base and the Pin-Fin ratio. (Pin refers to the height of the fins of the heat sink, and Fin refers to the distance between two adjacent fins.)

    Pin-Fin ratio is the height of Pin (excluding the thickness of the base) divided by Fin. The larger the Pin-Fin ratio, the larger the effective heat dissipation area of the heat sink, which means the more advanced aluminum extrusion technology.

Aluminum radiator

Copper radiator

    Copper has a heat transfer coefficient of 1.69 times that of aluminum, so pure copper heat sinks can remove heat from the heat source more quickly, all other things being equal.

    However, the texture of copper is a problem. Many of the advertised 'pure copper radiators' are not really 100% copper. In the copper list, copper containing more than 99% is called acid-free copper, and the next grade of copper is copper containing less than 85% copper. The copper content of most pure copper heat sinks on the market today is somewhere in between. Some inferior pure copper radiators do not even contain 85% of copper. Although the cost is very low, their heat transfer capacity is greatly reduced, which affects heat dissipation.

     In addition, copper also has obvious shortcomings, high cost, difficult processing, and too large heat sinks hinder the application of all-copper heat sinks. The hardness of red copper is not as good as that of aluminum alloy AL6063. Some mechanical processing (such as grooving, etc.) is not as good as aluminum; copper has a much higher melting point than aluminum, which is not conducive to extrusion and other problems.

Copper-aluminum bonding technology

    After considering the shortcomings of the two materials, copper and aluminum, some high-end heat sinks in the market often use a combination of copper and aluminum. These heat sinks usually use a copper metal base, while the heat sink fins use aluminum alloy. 

     In addition to the copper base, there are also methods such as using a copper post for the heat sink, which is the same principle. With a high thermal conductivity, the copper bottom can quickly absorb the heat released by the CPU; the aluminum fins can be made into a shape that is most favorable for heat dissipation by means of complicated processes, and provide a large heat storage space and quick release. 

    To improve the LED luminous efficiency and service life, solving the heat dissipation problem of LED products is one of the most important issues at this stage. The LED industry has strict requirements on the accuracy of the line alignment of the heat dissipation substrate itself, and it needs to have high heat dissipation and small. 

     Dimensions, metal line adhesion and other characteristics, therefore, the use of yellow light micro-film production of thin film ceramic heat sink substrate, will become one of the important catalysts to promote LED high power upgrade.