The LED light cooling substrate

The LED light cooling substrate

Heat the webmaster if use LED light the heat dissipation substrate materials itself has a better thermal conductivity, will heat source from crystal grain export LED. Therefore, we from the heat in the narratives, LED way can be heat LED base board subdivision two large categories, respectively crystal grain of substrate and LED system, the two kinds of different circuit of the base board heat were carrying LED grain and LED chip will LED grain light at the heat energy produced by cooling and grain size, LED board to system, and then by the atmospheric environment circuit absorption, in order to achieve the effect of heat spread.

With the global environmental protection consciousness, saving energy saving up has become a current trends. LED industry in recent years is the most popular one of purpose sort industry. Now, LED products already have an energy, save electricity, high efficiency, the reaction time is fast, and long life cycle, and does not contain mercury, has the environmental benefits; Etc. However, often LED high power input power is about 20% can convert light, only 80% of the electrical energy are converted to heat energy.

Generally speaking, when LED the heat energy produced if cannot export, will make LED to high temperature, and then face "shadow ring product life cycle, the luminous efficiency, stability, and surface temperature, and LED the Luminaire efficacy and life of the relationship between the following will use the relationship chart for further instructions. 1, LED heat way

According to different types of packaging technology, the heat dissipation methods also different from all kinds of cooling way, and LED the way for roughly can:

Cooling way explains:

(1). From the air cooling

(2). Heat directly by the System circuit board export

(3). The heat through gold line is derived

(4). If the eutectic and Flip chip process, through the heat through holes to system is derived and circuit board

Generally speaking, the LED grain (Die) to a gold line, eutectic or flip chip way in the base board links (Substrate of LEDDie) to form a LED chips (chip) and then LED chips will be fixed in the way electricity board System (System circuitboard). Therefore, LED the way for possible heat directly from the air cooling, or the grain substrate by LED to the system to the atmospheric environment. Circuit board And by system circuit board to heat the rate of atmospheric environment based on the design of the light lamps and lanterns or system. However, the current stage of the whole system bottlenecks, most of the heat happened in will heat transmission to the grain from LED base board to system mainly circuit board. This part of the cooling way: one for may directly by grain base board heat to the system board, in this cooling circuit in the way, and its LED grain substrate materials scattered ability of heat that for quite important parameters. On the other hand, LED the heat produced in the metal wire through electrode will also be to system circuit boards, in general, use gold thread way by the heat, and electrode by metal line itself is the slender geometry and limited; Therefore, recently have namely Eutectic (Eutectic) or flip chip (Flipchip engagement way, the design sharply reduce the length of the wire, and increase the cross section area, so a wire, wire electrode by LED to system of circuit board cooling efficiency will improve. Through the above explanation, that the cooling way heat substrate materials and the choice of mode in the encapsulation of the grain size of the LED LED hot on the management of scattered extremely important a ring, post will be LED to heat boards do outline.

2.1 system circuit board

The system mainly as a circuit board LED cooling system, finally will lead to heat radiator fins, shell or the atmosphere of the material. In recent years the printed circuit board (PCB) production technology has very strong, the early LED products in PCB board of the system is given priority to, but with high power LED increased the demand of thermal capacity, PCB material Co., LTD, making them unable to apply to its high power products, in order to improve high power LED heat dissipation problems, recent has developed a high fever conductivity coefficient aluminum plate (MCPCB), the heat with metal material characteristics better features, has reached a high power products of cooling purposes. However, along with the brightness LED the continuous development of the requirements and performance, although system circuit board can chip LED the heat produced in the effective heat to atmospheric environment, but LED grain the heat energy produced is not effective from grain of transmission to system YiYan circuit boards, the higher power, when LED to improve efficiency, the whole LED's heat bottleneck will appear in the base board heat LED grain.

2.2 LED grain base board

Grain base webmaster if LED as LED grain and system between the media are board heat energy, etc.the through line, eutectic or flip chip of the process and LED grain union. And based on the heat on market considerations, current grain base board mainly LED ceramic substrate, primarily, by line preparation of method can distinguish different roughly for: thick film ceramic substrates, low temperature co-firing multi-layer ceramics, and film ceramic substrates three, in the traditional high power LED components, in thick film or low temperature co-firing ceramic substrates as grain cooling substrate, again with gold thread will play way LED grain and ceramic substrates combined.

As mentioned, this foreword golden line link limits the quantity of heat to the effectiveness of the lost along the electrode contact. Therefore, in recent years, the domestic giant toward all solve the problem and try hard. The solving two ways, one for looking for high heat coefficient of substrate materials, to replace the alumina, contains the silicon substrate, silicon carbide substrate, the anodic aluminum plate or nitriding aluminum plate, including silicon and the silicon substrate carbon of semiconductor material characteristics of its present meet the test of a harsh, and anode, aluminum plate is because its anode oxidation layer of insufficient strength and easy for chipped conduction, make its cause in practical application, and so on, the limited more mature and general acceptance is higher for the aluminum nitride heat as base board; At present, however, limited to nitriding aluminum plate is not preach all thick film process (material in silver glue should be approved by 850 ¡æ after printing atmospheric heat treatment, make its appear material reliability problems), therefore, nitriding aluminum plate lines to film ChengBei system should be made.

The film ChengBei system with the nitriding aluminum plate greatly accelerated the heat from grain LED through substrate materials to system performance, so the circuit board to sharply reduce heat LED by metal line by grain to the burden of the circuit board, and the system to achieve high fever spread effect.

Another hot scattered solutions to its substrate LED grain eutectic or flip chip way link, and so, through electrode lead to increase of circuit board system cooling efficiency. However this process of the substrate for accuracy and substrate wiring circuit surface flatness requirement is extremely high, this makes thick film and low temperature co-firing ceramic substrates for accuracy of process nets edition web through problems and sintering contraction ratio problem and not apply to use. At present many to import film ceramic substrates, in order to solve the problem. Thin film ceramic substrate to HuangGuangWei way of preparation of circuit, supplemented by electroless plating or increasing the thickness of the way that the product line with high lines with high degree of accuracy characteristics.

Eutectic/flip chip process with film ceramic substrate, certainly will will be greatly heat to the power and light up LED product life. In recent years, due to the development of the aluminum plate, the system the circuit board of heat, even improve gradually get gradually to the soft circuit board development can bend. On the other hand, the LED grain base board also gradually towards reduce its thermal resistance direction.

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