LED packaging technology elements

led with environmental protection, long life, small size, high directivity, in solid form is not easy to damage ... etc., have gradually replaced the traditional tungsten (incandescent), CCFL fluorescent lamps, but for different application needs, there is still light efficiency, light type, cooling and cost, and many other issues, in order to better meet the needs of the product must be from the LED component side of the package started to improve ...
LED as light-emitting material properties and principles different from conventional light sources, it has many advantages of the use, just replace the light source is generally routine applications, LED solid-state light-emitting components still need multiple design and improvement, to the luminous efficiency, color rendering, illumination type, to obtain enhanced power efficiency, etc., in order to test the market through lighting applications.

In general lighting (General Lighting) market, LED solid state lighting you want to speed up the spread, so components must be in the short term costs, production technology, certification standards in place ... and other aspects of eleven, the performance of technology to enhance the color temperature, color rendering and the photoelectric conversion efficiency, from the perspective of the lighting system to think, still need to solve the LED light source, AC / DC power conversion, LED drivers control, thermal and optical components for processing key.

Note: Special package of LED components, may be due to different lighting needs to be optimized, both for photo Osram LED lighting application design components of the module.

Thin-film chip packaging technology development focus of lighting applications

LED light source applications, the key to the core of development in chip technology, which affect the characteristics of the LED components for luminous efficiency is the key to the growth of technology and the wafer substrate material differences.

In the LED substrate material, in addition to the traditional sapphire substrate, the silicon (Si), silicon carbide (SiC), zinc oxide (ZnO), gallium nitride (GaN) ..., are currently the development of LED components focus on the development of light regardless of the lighting or the application is to create an atmosphere of ambient light, covers a large, low-power application mode, the chip substrate technologies to enhance the goal is to create more efficient, more stable LED chip.

Improve the optical efficiency of LED chips, LED lighting application technology has become the key indicators, such as changes in the structure by the chip, the chip surface rough design, the design of multi-quantum well structure forms through multiple process technology improvements, the current have to make a single LED chip has a luminous efficiency breakthrough.

The thin-film chip technology (Thin film LED), is used to develop the key high-brightness LED chip technology, which focused on reducing the chip side light loss through the bottom of the reflector with, you can make the chip more than 97% of the electro-optical reaction, so that direct light from the front of the chip output, a substantial increase in lumen LED units.

Enhanced package technology to improve efficiency and light-emitting type
Observation of the current common high power LED packaging technology can be divided into single-chip packages, multi-chip packaging and chip board packaging integrated three technologies, and through optimization of packaging, enhance the luminous efficiency of LED chip, heat dissipation and product reliability.

In a single chip package, the single LED chip allows light to play a substantial advantage, for example, for the improvement of luminous efficiency, heat thermal impedance adjustment, or made of easy-to-SMT assembly production line to produce the form. Single chip package, the LED light emitting diode of the most common bottleneck is that the technology must yield control for each chip, because the single chip package, package deal, if the chip itself is already damaged or inefficient, packaging the finished product will show the same materials and parts, and the other stages in the package body can also be phosphor package deal, to improve the final product output color temperature or light type.

Note: SMT LED components form plastic material through the fill and form changes, resulting in multi-product characteristics. The picture shows the PLCC (Plastic Leaded Chip Carrier) in the form of SMT LED.

To Osram's Golden DRAGON Plus LED, for example, is taken to fill silicone seal design, LED components packaged with 170-degree beam angle can be easily carried out 2 times optical lens or reflector to improve the optical properties of the component, Golden DRAGON Plus LED silicone lens has a high temperature and low light attenuation characteristics. Single-chip package of considerable advantage, especially in light efficiency, thermal efficiency and enhance the ease with light, high-reliability components are quite worthy of attention.

Multi-chip integrated package of small size with high flux performance can be

The so-called power in unity, is also true on the LED component packages, if more than one LED chip will be packaged in the same plane, can be integrated out of a high-power integrated components. Multi-chip integration of components is also a common high-power, high brightness LED components of the most common application package, can be divided into low-power and high-power integrated form of the two chips.

In the low-power applications, the majority is to take six low-power LED chip integration, made out of 1 watt high power LED solid-state light-emitting components of the most common, and the use of six low-power chips integrated 1-watt high-power applications, the advantage is relatively lower production costs, and sources of more stars in the form if the chip yield problems can also be used to complement the surrounding chip due performance, the product yield is unlikely that the negative issues, low-power integrated multi-chip package, is currently the production of high-power LED components common form.

In the high-power chips integrated part to Osram's OSTAR SMT series, for example, its shape has been optimized package design, footprint size is relatively small, the final component that allows the product per watt thermal impedance control at 3.1 ℃ or so, drive power as high as 15 watts, this package design has a lot of advantages, especially in the confined space to reach the general components of the few high-flux LED performance.

Chip On Board can effectively improve the heat dissipation problem
COB (Chip On Board) LED light panels polycrystalline, as the traditional semiconductor technology development application form, which means the LED chip directly fixed on the printed circuit board (PCB), COB technology is currently only has 0.3mm thickness LED components design . As the LED chip can directly contact with the PCB to increase the heat transfer area, the LED heat dissipation common solid state light sources can also be so improved.

Most components of the LED printed circuit board arranged in the formation of multiple LED light combination, can enhance the solid-state light source LED lighting, low-power drive components will normally apply the core material for the FR4 printed circuit board to the general product of the 2 groups structure, in response to high-power drive applications, it will shift to the metal core PCB LED components need to strengthen the high heat environment, by the metal core PCB to reduce the thermal impedance.

Metal core PCB is used MCPCB (Metal Core Printed Circuit Board), the lower the thermal resistance of components to meet design requirements, design architecture is typical of MCPCB formed on the metal surface while the thin line isolation design, and circuit traces line must be used to provide compounds of nickel metal welding production line can be machined surface, they must have to avoid the isolation layer short-circuit, without sacrificing cooling rate of thin design, heat transfer process in order to minimize thermal resistance. Most selected aluminum as the core, with a low cost, good heat dissipation and better corrosion resistance and so on.

Relatively new production methods, the LED chip is directly mounted on printed circuit board, or with a plug and play integration of components, and COB package form, its purpose is to provide discrete than the existing arrangement of the LED components with higher performance, lower heat resistance of the product form, so that end products can be developed via a simple second time, a system mature enough to enter the lighting market products. (more information please visit www.greendyled.com)