Ultra-high thermal conductivity substrate for high power LED applications

He Zhongliang, General Manager of Shenzhen Huanji Industrial Co., Ltd.

Established in 1992, Huanji Industrial Co., Ltd. has a considerable history and scale. The company has developed and completed LED new high thermal conductivity aluminum substrate, and has applied for patents and has mass production capacity.

As LED materials continue to advance, brightness, power consumption and heat are also increased, especially the greatly increased heat needs to be eliminated as quickly as possible, otherwise it will reduce its luminous efficiency and accelerate the deterioration of LED components, so LED heat Management has become quite important.

Since only 15-20% of the input power of high-power LEDs is converted into light, the remaining 80-85% is converted into heat. If these heats are not properly discharged to the outside world, the interface temperature of the LED die will be too high and the luminous efficiency will be affected. Luminous lifetime

70% of LEDs will fail due to excessive interface temperature. LED product life cycle, brightness, product stability, etc. will all fail as the interface temperature increases.

When the LED heat source cannot be effectively exported, it will lead to an increase in the LED interface temperature, which will in turn affect the output efficiency of the light.

As the brightness of LED dies increases, the wattage of power consumption of a single LED increases from 0.1W to 1W, 3W, and 5W. The thermal resistance of the LED package module is 250 to 350K/W. Greatly reduced to less than 5K/W now. Due to the development of such technology, LEDs are facing increasingly severe thermal management challenges. The specific heat of LEDs is lower than that of ICs. When the temperature rises, not only will the brightness decrease, but when the temperature exceeds 100 °C, the deterioration of the components will be accelerated. The heat dissipation technology of the LED component itself must be further improved to meet the heat dissipation requirements of high power LEDs.

There are two kinds of grooving and smashing nails commonly used in the process.

Trenching has the following drawbacks

1, the depth is not easy to control
2. There are processing marks on the surface of the substrate, and the surface is uneven.
3. High processing cost
4, the surface can only be aluminum, not easy to solder
5, the bond is easy to fall off

The drawback of smashing nails is

1, complex processing
2. The cooperation between the nail and the substrate is easy to cause problems, and the heat conduction is affected when the fit is not tight.
3, the height of the nail itself will lead to uneven surface, is not conducive to sealing and other subsequent processes.

The company currently uses a new process to solve the problem of heat dissipation. At present, this process has applied for a patent, and the product produced by the new process has the advantage of

1, the board surface is flat
2, the surface can choose a variety of gold, silver, copper, tin, etc.
3, can meet various requirements

The following are the results of the testing of the ring-based products in the testing organization:

Sample background

LED is Osram, 2pcs of aluminum substrate ring base, 1pcs of a brand, temperature comparison test is now carried out

Temperature test

First, test equipment: temperature tester, DC voltage regulator, multimeter, etc.;
Second, the test environment: 25 ± 5 ° C, normal atmospheric pressure;
Third, the test steps:

1. First measure the positive and negative LEDs with a multimeter, then place a thermocouple on the aluminum substrate of the LED and the white ring.
Input DC 350mA and 700mA current respectively, work according to the conditions in the table, and record the temperature (please note that the glue should not be solidified on the LED during the process of thermocouple to avoid damage to the LED, and need to add heat sink during the test of 700mA current);

Sample type

2Pcs of ring-based aluminum substrate, temperature comparison test of 2Pcs of aluminum substrate with thermal conductivity of 0.5, 1.0, 2.0, 4.0

First, test equipment: temperature tester, DC voltage regulator, multimeter, etc.;
Second, the test environment: 28 ± 2 ° C, normal atmospheric pressure;
Third, the test steps:

1. First measure the positive and negative LEDs with a multimeter, then solder a conductive wire on the aluminum substrate of the LED, input 850mA current, 3.6V voltage, work for 30 minutes, 60 minutes, 90 minutes, and record for 30 minutes. 60 minutes, 90 minutes temperature

Fourth, test data:

From the experimental data, it can be seen that the aluminum substrate with different thermal conductivity has a temperature of about 20 degrees, and the ring-based ultra-high thermal conductivity aluminum substrate is 20 degrees Celsius lower than the temperature of the aluminum substrate of the manufacturer. Thermal conductivity, welcome to use the factory test to provide valuable advice.

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