What‘s Next for High-Power LEDs？

　　高效發(fā)光二極管是令人印象深刻的設(shè)備。許多領(lǐng)先的半導(dǎo)體公司銷售經(jīng)過驗(yàn)證的商業(yè)設(shè)備，功效超過100流明/瓦特，壽命超過50000小時(shí)。

　　然而，在當(dāng)代的產(chǎn)品表現(xiàn)良好，氮化銦鎵（InGaN）基白光LED（最常見的類型，產(chǎn)生今天）有一個(gè)約250流明/ W的理論有效性限制，因此還有很大的改進(jìn)余地。諸如載流子注入、內(nèi)部量子和光提取效率等因素受到學(xué)術(shù)界和研究人員的密切關(guān)注，它們?yōu)轭I(lǐng)先的LED公司工作。

　　本文回顧了這些科學(xué)家和工程師迄今所取得的進(jìn)展，并對(duì)我們可能看到的改進(jìn)做了展望。

　　Green credentials

　　LEDs are touted as the future for environmentally-friendly lighting. Some of their green credentials come from sustainable manufacturing techniques and the use of recyclable materials， but the major benefits for the planet are in the power savings LEDs exhibit compared with traditional lighting sources.

　　Although there are several techniques for producing white light from LEDs， most contemporary commercial devices combine an InGaN LED， producing light in the blue part of the spectrum， with an yttrium aluminum garnet （YAG）-based phosphor. The phosphor absorbs some of the blue light from the LED and then re-emits it across a broad range of wavelengths comprising some green and red， and a lot of yellow. The combination of blue light from the LED and the range of colors from the phosphor appears as white to the eye （see the TechZone article “Whiter， Brighter LEDs”）。 The rest of this article will be restricted to consideration of this type of white LED.