As the LED technology advances, LED applications are increasingly diversified, but because of high power LED input power is only 15 to 20% converted into light, the remaining 80 to 85% is converted into heat, if the heat is not timely to the outside, then Will make the LED chip interface temperature is too high and affect the luminous efficiency and luminous life.
With the continuous evolution of LED materials and packaging technology to promote the LED product brightness continues to increase, LED applications more and more widely to LED as a display backlight, is a recent hot topic, mainly different types of LED backlight technology Respectively, in the color, brightness, life expectancy, power consumption and environmental protection requirements are more than the traditional cold cathode tube (CCFL) more advantages, and thus attract the industry to actively invest.
The initial single-chip LED power is not high, heat is limited, the heat problem is not, so its packaging is relatively simple. But in recent years, with the LED material technology breakthrough, LED packaging technology also will change from the early single-chip shell-type package gradually developed into a flat, large-scale multi-chip package module; its current from the early 20mA Around the low-power LED, progress to the current 1/3 to 1A or so high-power LED, a single LED input power up to 1W or more, even to 3W, 5W package more evolution.
As the high-brightness high-power LED system will be derived from the thermal problems will affect the product quality key, to LED components of the heat quickly discharged to the surrounding environment, the first must be from the packaging level (L1 & L2) heat management to proceed. At present the industry's approach is to LED chip with solder or thermal paste followed by a soaking film, through the heat sink to reduce the thermal resistance of the package module, which is currently on the market the most common LED package module, the main source of Lumileds, OSRAM, Cree and Nicha LED international well-known manufacturers.
Many end applications, such as mini-projectors, automotive and lighting sources, require more lumens or thousands of lumens in a specific area, and the single-chip package module is clearly insufficient , To multi-chip LED package, and chip direct bonding substrate is the future development trend.
The problem of heat dissipation is a major obstacle in the development of LED objects for lighting, the use of ceramic or heat pipe is an effective way to prevent overheating, but the thermal management solution to make the cost of materials increased, high power LED thermal management designed to effectively reduce the The R junction-to-case is one of the material-based solutions that provides low thermal resistance but high conductivity through chip attach or hot metal methods to deliver heat directly from the chip to the Outside the package.
Of course, LED cooling components and CPU cooling is similar, are by the heat sink, heat pipe, fan and thermal interface material composed of air-cooled module, of course, water cooling is one of the thermal countermeasures. To the current most popular large-size LED TV backlight module, 40-inch and 46-inch LED backlight input power of 470W and 550W, respectively, 80% of the heat into the heat, the required heat 360W and 440W or so.
So how do you take these calories away? The current industry has a water-cooled way to cool, but with high price and reliability and other concerns; also useful heat pipe with the heat sink and fan to cool, for example, Japanese manufacturers SONY 46-inch LED backlight LCD TV, but the fan power and Noise and other problems still exist. Therefore, how to design a fanless cooling method may be the key to determining who can win in the future.