Plant lighting has been adopted in green houses of high-valued vegetables, fruits, and flowers. The original intention of using plant lighting was to increase photosynthesis, or to control the life cycle and to minimize the influence of climate. Currently, the main sources of plant lighting are High Pressure-sodium Lamp (HPS) and Compact Fluorescent Lamp (CFL). 

Plants only absorb particular wavelength at blue and red in spectrum, especially at red. However, the red wavelength of HPS and CFL is low. By using LED as light sources, specific wavelength can be adjusted, power efficiency can be increased, and plant growth can be improved. Although, compared with traditional light sources, the cost of LED products in plant lighting applications is higher, the evaluation should focus on the energy-saving and Wall-Plug Efficiency(WPE). 

The external luminous efficiency of the original Epistar WPE is about 30% to 35%, which although outperforms peers in the industry, still needs improvement to replace the traditional light sources. Thus, our R&D team adjusted the epitaxy structure to improve internal quantum efficiency and applied new technology platform to increase external luminous efficiency. In 2009/Q2, new 660nm LED product (BRPN42B) had been successfully developed. The WPE of BRPN42B can be up to 40~44%, which is a record high in the world.