White LED Packaging Technology

LED packaging process

The packaging process of LED devices is a very important task. Otherwise, LED devices will suffer from serious light loss, low light flux and light efficiency, uneven light color, and short service life. The packaging process determines the success or failure of the device. The typical traditional structure of the currently developed white LED is difficult to adapt to the requirements of being a lighting source. The mold particles, brackets, resins for packaging, optical structures, etc. need to adopt new design ideas, new processes and new materials to achieve process perfection and be suitable for the development of solid lighting sources. On the one hand, people inherit, but more importantly, they abandon the old framework and innovatively launch new white light LED light sources with their own characteristics. The following issues should be given priority:

1. Light extraction rate. The external quantum efficiency is low, and the physical barrier of refractive index is difficult to overcome.

2. Thermal conductivity.

3. Packaging process with uniform light color and high light flux;

4. Packaging resin, high transmittance, heat resistance, high thermal conductivity, UV and sunlight radiation resistance and moisture resistance.

5. Coating phosphor glue process. The current glue dripping process is backward, the yield is low, the consistency is poor, and the labor intensity is high.

2. White LED lighting fixtures

We must realize that there is a difference between the concepts of single or multiple white LEDs and lamps used as lighting sources. So far, the white LEDs developed and produced at home and abroad are far from meeting the requirements of lighting sources. We should use and give full play to China's advantages and advanced technologies in the development of various types of small compact fluorescent lamps in the world, seize opportunities, and make a difference in the development of new solid light sources. Some major problems faced by white LEDs in realizing lighting sources are similar to those that have been solved or are being solved by compact fluorescent lamps.

1. The AC-DC conversion circuit installed in the lamp should adapt to the characteristics of LED current drive;

this power supply should have both a forward current output close to constant current required by the LED and a high conversion rate to ensure the safe and reliable operation of the LED, and of course pay attention to the cost.

2. LED lamp reliability

The factors that affect the reliability of lamps are mainly LED devices and the above-mentioned electrical components. So far, no manufacturer of white LED devices has provided detailed information or technical specifications on device failure rates, let alone standards for LED lamps used as lighting sources.

3. Heat dissipation of lamps

Overcoming the heat conduction of a single LED does not mean solving the heat dissipation of lighting source lamps. With the development of high-power, large-size, and high-brightness chips, the heat dissipation of LED devices and lamps must be solved.

4. Uniformity of light color and optical system of lamps

Due to the special structure of small LEDs, the light characteristics are not like incandescent bulbs and fluorescent lamps, and there is a problem of uneven white light color. After being combined into lighting fixtures, how is the uniformity of light color? How the light distribution of the "secondary light source" composed of several LEDs and the optical system that constitutes the LED lamp meet the requirements of the lighting source is a complex system project, which needs to be seriously considered and solved.

People should consider the development of white light LED lamps in 5 or 10 years. Green, intelligent, automatic dimming system, practical functionality and decorative beauty are one of its development goals.