Technically, the luminous efficiency of LED chips is a key factor to improve the development of LED applications. According to Mr. Mantie Lee, the general manager of Shenzhen Ledman Optoelectronic Technology Co., Ltd., the luminous efficiency of LED chips was continuously increasing recently. The light efficiency of 1W high-power LED chips available in the market has reached up to 100lm/W.
The LED packaging technology is another important factor. Although their effects on improving luminous efficiency are not obvious, they have closed relations with the reliability of LEDs. Differences in LED packaging technology have direct impacts on the LED quality. Good packaging and cooling design enable LED chips work under 60 centigrade, the lifetime of which can be more than 50,000 hours. On the contrary, weak packaging will cut the lifetime of LEDs by half or more. 90% luminous efficiency of LED lamps is determined by the luminous efficiency of LED Tunnel Light chips. Another 10% is determined by packaging structure and phosphor excitation efficiency. 30% of the reliability of LED lighting fixtures depends on LED chips and another 70% depends on packaging materials, packaging structures and packaging management. 50% cooling effects of LED lamps is determined by package heat dissipation structure and materials.
Packaging technology is especially important to LED lighting industry. Currently, the luminous efficiency of some highly efficient LED road lamps has been more than 80lm/W, contributed by the improvement of LED chips’ luminous efficiency. These road lighting devices have obvious advantages in energy-saving, the reliability and service life of which still rely on the further improvement of packaging technology. The current bottleneck of LED street lighting technology is light attenuation and reliability rather than luminous efficiency. Using high-powered LED packaging technology can significantly improve the light attenuation and reliability of LED road lamps.
For road lamps, packaging has very limited effects on improving their luminous efficiency. They rely more on the improvement of LED chip technology, while stability, reliability and consistency more rely on production process. All LED street lighting applications are volume applications. Series-parallel technology is needed regardless of the scale of programs. There are hundreds of components used in one LED street lamp. Any failures of these units will put an impact on the original design of the current and voltage threshold, and consequently the working condition of the whole lamp.