白熾燈泡和螢光燈管可以提供基本的照明需求，卻無法滿足人類對不同時段有不同光色自然光的渴望。為了實現類太陽光照明，燈具之放射光必須和日光光色相近，同時也須有寬廣的色溫變化；然而，不論是先前的OLED，或是最新的LED，皆無法達到太陽光般的廣色溫。因此，本文將介紹第一個人造太陽光光源，其光色變化不僅和日光相近，範圍更涵蓋2300+-70K至7900+-1400K，足以匹配清晨曙光的3250K、正午日光的5500K至落日餘暉的 500K，甚至包含高緯度正午的8000K。文中將簡介OLED的諸多侵入性特色，並闡述色溫對人類健康的影響。

Incandescent bulbs and fl uorescent tubes provide fundamental lighting needs but barely satisfy our desire for natural lighting, as from the sun, with time-varying color temperature. To have sunlight-style illumination, emission with daylight chromaticity and a wide color-temperature (CT) span is essential. However, no single lighting device,
including previously published white organic light-emitting diodes (OLED) as well as the latest white light emitting diode (LED), exhibits daylight-like emission with a color temperature range covering that of sunlight. Here we demonstrate a man-made lighting device that is composed of a single simple OLED capable of yielding daylight chromaticity with color-temperature ranging from 2300+-70 to 7900+-1400 K, covering that of sunlight, i.e. 3250 K at dawn, 2500 K at dusk, and 5500 K at noon or 8000 K at noon in high-latitude country. Throughout this context, we will fi rst introduce some disruptive features of OLED, followed by an elucidation on the effect of CT on human health.