(1) The rival of LED lighting products-heat dissipation

　　In recent years, with the rapid advancement of LED chip technology, the road  commercial application of LEDs has been very mature. LED products are known as "green light sources" because of their small size, low power consumption, long service life, high brightness, environmental protection, sturdiness and durability, as well as significant energy-saving LED lamps. Using ultra-bright and high-power LED light source, with high-efficiency power supply, it can save more than 80% of electricity than traditional incandescent lamps, and the brightness is 10 times that of incandescent lamps under the same power. The long life span is more than 50,000 hours, which is more than 50 times that of traditional tungsten filament lamps. The LED adopts a highly reliable advanced packaging process-eutectic welding, which fully guarantees the long life of the LED. The luminous visual efficiency can be as high as 80lm/W or more, a variety of LED lamp color temperatures are available, high color rendering index, and good color rendering. LED light string LED technology is advancing with each passing day, its luminous efficiency is making amazing breakthroughs, and the price is constantly decreasing. As a lighting product, it has penetrated in thousands of households and streets.

　　However, LED light source products are not without any shortcomings. Like all electrical products, LED lights will generate heat during use, leading  an increase in ambient temperature and their own temperature. LED is a solid-state light source with a small light-emitting chip area and a large current density through the chip during operation; while the power of a single LED chip is relatively small, and the output luminous flux is also low. Therefore, when practically applied  lighting equipment, most lamps require The combination of multiple LED light sources makes the LED chip denser. And because the phoelectric conversion rate of the LED light source is not high, only about 15%  35% of the electric energy is converted in light output, and the rest is converted in heat energy. Therefore, when a large number of LED light sources work gether, a large amount of heat energy will be generated. If this heat cannot be dissipated as quickly as possible, it will cause the junction temperature of the LED light source  rise, reduce the phons emitted by the chip, reduce the color temperature quality, accelerate the aging of the chip, and shorten the life of the device. Therefore, thermal analysis and optimal design of the heat dissipation structure of LED lamps become extremely critical.

　　Figure 1 LED heat transfer diagram

　　Figure 2 LED CFD analysis

　　Figure 3 Optical output and junction temperature characteristic diagram

　　Based on years of development experience of LED products in the industry, a very complete design theory system has been formed. As a lighting product structure designer, it is equivalent  standing on the shoulders of giants. However, it is not that it is so easy  reach the p on the shoulders of giants. There are many problems that need  be overcome in daily design. For example, from the perspective of cost, in the design, it is necessary  meet the heat dissipation requirements of the product, but also  minimize the cost; currently, the most commonly used method on the market is  use aluminum alloy fins for heat dissipation. In this way, how do designers  determine the gap distance between the fin and the fin and the height of the fin, as well as the influence of the structure of the product on the airflow and the orientation of the light-emitting surface, will lead  inconsistent heat dissipation. These are problems that plague designers. Usually, an experienced old designer will design based on experience, while a young designer is not so lucky because he does not have so much experience  learn from. What should I do? Xiaobian Huagong is also a young designer and does not have much product design experience. I usually use thermal simulation  optimize the design of the product and reduce the LED junction temperature through the simulation results. Figure 4 and Figure 5 below are the two simulation results obtained by adjusting the product structure through thermal simulation of the same product.

　　Figure 4 Thermal simulation optimization design simulation result 1 of a certain lighting product

　　Figure 5 Thermal simulation optimization design simulation result 2 of a certain lighting product

　　The following two figures, Figure 6 and Figure 7, are our actual product design, by simulating the use form of the product,  simulate the product heat dissipation, through the heat dissipation simulation cloud diagram, we can clearly see that in different use situations, the heat The distribution and heat radiation state inside and outside the product.

　　Figure 6 A simulation diagram of a luminaire when it emits downward light

　　Figure 7 A simulation diagram of a lamp when it emits light  the side

　　The above are actual cases in our daily design. In the design process of LED lamps, there are many ways  reduce the junction temperature of the LED and ensure the life of the LED: ① Strengthen heat conduction (there are three ways of heat transfer: heat conduction, convection heat exchange and radiation heat exchange), ②, select Low thermal resistance LED chips, ③, under-load or overload use the rated power or current of the LED (it is recommended  use 70%~80% of the rated power), which can effectively reduce the LED junction temperature.

　　Then  strengthen heat conduction, we can adopt the following methods: ①, a good secondary heat dissipation mechanism; ②, reduce the thermal resistance between the installation interface of the LED and the secondary heat dissipation mechanism; ③, enhance the contact between the LED and the secondary heat dissipation mechanism The thermal conductivity of the surface; ④, the structure design adopts the principle of air convection.

　　Therefore, heat dissipation is an insurmountable gap for product designers in the lighting industry at this stage. At this point, I believe that with the revolutionary advancement of technology, the impact of heat dissipation on LEDs will gradually become smaller. We are also trying  find ways  reduce the junction temperature of LEDs, ensure the life of LEDs, and make cost-effective products through application methods. .

　　Original: Huagong

　　Shenzhen  Lighting is a lamp manufacturer focusing on R&D and production of LED landscape lighting and outdoor lighting. It has 9 years of experience in military industry lighting services. It is located in Shenzhen Baoan. Its products cover: stadium lighting, LED sports lighting, stadium lights, LED stadium lights, High bay lights, high bay lights manufacturers, LED workshop lights, workshop LED lights, tunnel LED lights, LED tunnel lights, LED wer chandeliers, street lights, LED workshop lights, LED squares, lamps, LED lights, high pole lights, wer chandelier, LED Street lights, LED lamps, LED high pole lights, etc. For many years, our company has always put product quality in the first place. At present, the company has passed the ISO9001 international quality certification system, and the products have passed CE, ROHS, 3C and other domestic and international certifications and inspections. We insist on making cusmers feel free  buy and use LED lights. Philosophy and mission,  Lighting [Chongde Shangshan is the source of the original] look forward  cooperating with you for a win-win situation.