LED芯片取光结构研究现状与发展趋势

Situation Development of LED Chips on Light Extraction Structure

LED芯片取光结构是指在LED芯片上窗表面、台面四周、衬底、侧面等表面上加工出能改变光线传播方向,提高LED芯片出光效率的微结构。取光结构是提高LED芯片发光效率的关键技术之一。分析了各类取光结构的取光原理,详细论述了取光结构的研究现状,分析了取光结构的未来发展趋势。目前,主要是通过图形衬底、表面粗化、倾斜侧面、光子晶体及其复合取光结构来提高LED芯片的出光效率,出光效率一般可提高25%以上,有的甚至可提高195%。未来取光结构研究重点应集中在复合取光结构、多芯片集成封装模块的取光结构、高效率和低成本的制造方法以及由功能驱动取光结构设计并按要求控制其成形。

Light extraction structure of light-emitting diode（LED） Chips is a type of microstructure fabricated on the top surface of LED,periphery of the LED’s mesa,substrate and sidewall that can change light propagation and improve light extraction efficiency.Light extraction structure is one of the crucial technologies of enhancing luminous efficiency of LED chips.Light extraction principle of different light extraction structures was analyzed and recent research on light extraction structure was dissertated.Currently,the enhancing light extraction of LED is achieved through patterned sapphire,roughened surface,inclined sidewall,photonic crystal and their integration.Generally,25% improvement or above in efficiency can be attained.Some light extraction structures can significantly improve the light extraction efficiency by 195%.The probable further trend of the research on light extraction structure was discussed.The prior research areas for the future study of light extraction structure are coupling light extraction structure,light extraction structure applied for module of multi-chip package,high efficient manufacturing method with low cost,and function-driven design of light extraction structure and fabrication in the light of design requirements.