Kunshan thermal pad manufacturers for your interpretation from the heat dissipation technology to explore LED road light failure

Exploring LED Light Illumination Problem from Heat Dissipation Technology

The serious light failure of LED street lights needs to be solved from the fundamentals of LED heat dissipation technology. At present, the growth rate of LED street lamps in China is higher than that of other countries. According to statistics, it is predicted that 2010 will continue to dominate the global market. Last year, the Ministry of Science and Technology finalized the “Ten Cities, Ten Thousand” pilot project for semiconductor lighting application engineering, although it was through the central policy to create a model for economic development of market demand, but the first-line response on the actual case of the manufacturers is not as expected.

The gap between policy and market, in addition to the LED standard has not yet fully regulated for vendors to follow, another potential technical problem is that "LED lights are severely declining", resulting in the installation of LED lights less than a year can not pass the use of unit certification and acceptance. The aforementioned LED standard specification has been formulated in a unified way, and it is possible to draw up a final decision in the near future. As for the “serious light failure of LED street lights”, it needs to be solved from the root of LED heat dissipation technology.

Discussion on Causes of LED Lighting Failure

The temperature of the thermal shim in Kunshan is actually the key issue of the LED light failure, but the LED street light is stuck in this link. Because the LED street light has a higher luminous power than a household lamp, the manufacturers have made painstaking efforts in the design of the heat sink substrate fins and the heat dissipation module. After the assembly is completed, it is necessary to protect the exterior of the lamp cooling module and protect it from weather erosion. Unexpectedly, the external protection of the paint but the heat of the heat module is sealed back, resulting in poor heat dissipation LED epitaxy light failure.

LED epitaxial luminescence heat belongs to a small range of concentrated thermal energy. In the application of high-power street lamps, the power input power is also large, and the interface temperature of the LED is quite high. Under long-term continuous operation of the street lamp, the heat dissipation module cannot effectively dissipate heat. Will affect the LED life and luminous performance, such as the current serious LED light failure is caused by these factors. LED street light is used outdoors, there are environmental climate interference factors, so most manufacturers are to LED lamp radiator shell anode protection, or spray paint, in order to avoid acid and alkali material erosion. The life of anodizing is not long, and it will still be oxidized and discolored for a long time. If you want to remove the heavy industry, it will not only time-consuming and labor-consuming but also increase the maintenance cost; the cost of paint protection is low, and the protection effect is also good, but the general paint has no heat dissipation. Function, the paint itself will form a barrier effect, is equal to increase the heat resistance of the LED street lamp radiator, not only does not help, but because of the heat blockade in the heat sink, so that LED epitaxial luminous power is reduced, and finally lead to serious light failure . The above has been a serious problem in the LED lighting industry, is almost the main reason for the failure of the public engineering LED street light to pass the purchase unit acceptance.

LED Road Lighting Failure Solution

To solve these existing problems, it is recommended that manufacturers of street lamp manufacturers start with basic materials and solve the high-power LED heat source problem from the inside out. For example, in the bonding of the light emitting component and the aluminum substrate, the heat conductive adhesive plays a key role, and some manufacturers think that the thermal conductivity coefficient of the thermal conductive adhesive film or the thermal conductive adhesive pad is better, and the thicker the film thickness is, the better the thermal resistance is. No matter how good the thermal conductivity is, the thermal resistance of the film thickness is useless. What's more, the thermal conductive film or the soft thermal pad can't really adhere to the substrate, and there are many pores in the joint surface. These pores are viewed under an electron microscope and are like empty cavitations, which are another form of thermal resistance. With so many thermal resistances that interfere with heat conduction, the efficiency of heat dissipation and heat transfer is virtually reduced.

If the thermal resistance is low, the thermal conductive adhesive should be used for thermal conductive adhesives. The soft ceramic heat-conducting adhesive used for screen printing is different from the traditional adhesive heat-conducting adhesive film. The soft ceramic heat-conducting adhesive is a soft semi-liquid. When the screen printer scraper is applied to the aluminum substrate, the heat-conducting particles will penetrate into the pores of the substrate surface. Filled to full. This will result in a perfectly flat, non-porous plane that will fully adhere to the LED epitaxial carrier. In this way, the thermal resistance is reduced to a minimum, and the heat can be rapidly conducted. Naturally, the ambient temperature of the LED die is reduced, and the lifetime of the epitaxial crystal is also prolonged, and the occurrence of light failure is significantly delayed. In addition, due to the ductility of the soft ceramic thermal conductive paint used for screen printing, it will change with the thermal expansion and contraction of the aluminum substrate during high-temperature baking or reflow. The stress is very small and will not cause the aluminum substrate to warp. Will burst board.

The external protection of LED lamps is recommended to use LED lamps soft ceramic heat-dissipating paint. This spray-type soft ceramic heat-dissipating paint can be directly sprayed on the outside of the LED lamp. The construction is easy to operate, can adapt to various shapes of the heat dissipation structure, and can also be adjusted to different colors to meet the needs of landscape design. The soft ceramic particles in the spray-type heat-dissipating paint are treated with nano-particles. The fine particles are not only easy to operate with the spray gun, but also the heat-conducting particles on the same coated area are numerous and dense, and the area where the temperature is volatilized and dispersed is also enlarged. Let the heat energy of LED lamps be conducted quickly. Soft ceramic heat-dissipating lacquer is a thermosetting material that complies with the RoHS environmental safety regulations. The construction procedure is simple and does not require any special equipment. After being baked, it is heat-fixed and can withstand the high temperature of the LED for a long time without any qualitative change. Outdoor use of LED street lights, landscape lights, or LED advertising billboards, will also face the wind and rain, acid rain guano, air dust, black smoke emissions & hellip; acid and alkali damage. Therefore, this kind of sprayed soft ceramic heat-dissipation paint must have anti-acid and alkali resistance properties. The current range of acid and alkali resistance is PH3~11, which can effectively protect the appearance of LED outdoor lighting from being eroded.

The cost structure of LED lamps and lanterns along with the packaging technology, carrier board design, cooling module structure of the sophisticated development, the quality continues to increase, the cost with technology development and market demand and decline. However, there are not many companies investing in material improvement. This is mainly related to the history and habits of Taiwan's industrial and commercial development. Taiwanese manufacturers are more proficient in manufacturing processes and design, and have less ink on the basic research and development of materials. Therefore, on the issues of solving technical problems or reducing costs, it is more inclined to purchase thinking or management thinking. However, at the first time, the US and Japanese manufacturers will consider the application materials, reduce costs, improve quality, and increase profits from the perspective of innovation.

The output value of Taiwan's LED industry is among the top two in the world. Under the common theme of global warming and energy saving and carbon reduction, it has an organic industrial advantage. If Taiwanese businessmen can master the current stage of high-quality production technology, advanced manufacturing processes, and the development and improvement of materials, it is very likely that they will become the leading LED application field after the computer industry. At the beginning of 2010, within the foreseeable one or two years, LED lighting industry will be able to see the economic scale, which is also the key opportunity for Taiwanese companies to master.