Study Of Structure Design And Packaging Technologies Of White High-power LED

Light Emitting Diode (LED) whose advantages are energy saving, environmental protection, fast response, long life, light and so on, is the new generation of green light source after incandescent lamp and fluorescent lamp, and now it is gradually replacing traditional light sources and infiltrating into people’s daily life. But the luminous efficiency of LED is still difficult to increase, and for long wavelength blue LED chip (462.5-470 nm), there is no sophisticated packaging technology to obtain the white LED with the high luminous efficiency and high color rendering, semiconductor LED solid-state lighting, there are many practical issues that need to explore in the application. In this thesis, thses issuse were studiesd, enhance the performance of the high-power white LED from the structure design and packaging technology. Respectively using imitation lumens, integrated, COB package with three different packaging structures, some meaningful research results were obtained as following:1. The long band (462.5-470nm) chip were used to package out the white LED with high color rendering and high efficiency. Five schemes were designed and packaged to test out the luminous efficiency and color rendering index. As a result, it is found that using blue chip+yellow phosphor (530 nm YAG)+red phosphor (nitrogen) packaging scheme can achieve the better effect. The light efficiency of that scheme is 110.03 lm/W, while the color rendering index is 80.76. We used the long band (462.5-470nm) chip to package out high color rendering high luminous efficiency of white LED, which is useful to reduce the cost of lighting application of LED.2. The 50w-LED device was achieved with series and parallel connection by using the vertical structure chips whose optimal distance between the nearest chips was 2 mm. the integrated device samples were prepared. The driving voltage of this device is 30.2V, while the luminous efficiency is 95.1591m/w. It is found that this device has the high driving voltage with better luminous efficiency. This device provides a new design for the solid state LED lighting.3. The influence on the luminous efficiency LED with different chip arrangement by using the same packaging materials and process was studied. Three COB including the circular, triangular and rectangular structures COB were fabricated respectively. It is indicated that the COB packaging with rectangular arrangement has the best luminous efficiency in three types of COB packaging structures. As a result, it is suggested that the rectangular arrangement may be a better way to improve LED luminous efficiency, as for COB packaging chip which is concentrated in the center of the base board results in the balance of the light-emitting area.