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Science was way behind nature in developing LED light technology, a new study finds.
The beautifully colored wings of African swallowtail butterflies manipulate light using engineering tricks similar to those found in digital displays. The butterflies have black wings with bright patches of green and blue, which they use to communicate across long distances. Microscopic scales covering the wings absorb ultraviolet light and then re-emit it.
The re-emitted light interacts with fluorescent pigments found on the butterflies' wings to produce the vibrant green-blue color.
Like LEDs
Researchers investigating how the scales work found that they have many similarities to digital devices known as light emitting diodes, also known as LEDs, which are found in everything from computer and television screens to traffic lights.
The first LEDs invented in the late 1960s weren't very bright. They produced a lot of light but most of it tended to either become trapped inside the device or to spread sideways and become diluted.
In the early 1990s, engineers came up with ways to get around these problems. They outfitted LEDs with tiny mirrors that could reflect and channel the light and made microscopic holes in them to help the light escape.
Behind the butterflies
While studying the wings of swallowtail butterflies, researchers discovered that there were a lot of similarities between the scale coverings and LEDs.
The scales that cover the butterflies' wings contain tiny structures called "photonic crystals," which act very much like the microholes found in LEDs.
"[The scales] prevent the fluorescent light from being trapped inside the scales and from being emitted sideways," said Pete Vukusic of Exeter University, a researcher in the study.
The scales on the wing also have a specialized mirror underneath them, which act very much like the tiny mirrors found in LEDs.
The mirror reflects all the scattered fluorescent light it receives upward, giving the butterflies control over the direction in which in the light is emitted.
The study was reported in the Nov. 18 issue of the journal Science.
中文：
英国一项最新的研究结果显示，在研制发光二极管（LED）方面，科学家远远落在了自然造化的后面。科学家发现，非洲燕尾蝶漂亮的双翅处理光线的原理竟然与数码显示器的原理相类似。
据美国“生活科学网”日前报道，非洲燕尾蝶的翅膀底色为黑色，上面点缀着明亮的绿色和蓝色斑纹。研究人员发现，非洲燕尾蝶的翅膀上覆盖着细微的鳞状物，这些鳞状微结构吸收紫外线后，又将其重新发射回去。那些被重新发射的光线与蝴蝶翅膀上的荧光色素相互作用，就产生了明亮的蓝绿色。相隔长距离的蝴蝶用这种明亮的颜色进行相互沟通。
发光二极管的微孔
发光二极管最早于上世纪60年代被发明出来，如今在日常生活中随处可见，如电脑和电视屏幕以及红绿灯等都利用了发光二极管原理。但当时的发光二极管并不是非常亮。虽然它们可以产生出许多光线，但其中大部分不是在装置内部被截留了，就是从旁边发散出去，光也因此变淡。直到上世纪90年代初期，工程师们给发光二极管配备上了一些可以反射并引导光线的微小的“镜子”，才算找到了避免出现上述问题的方法。同时，工程师们还在二极管内部加上了一些细微的小洞，以防止光线被截留。
蝴蝶翅膀——天然的发光二极管
科学家在研究非洲燕尾蝶的时候，发现其翅膀上的鳞状覆盖物和发光二级管之间拥有很多相似的地方。
蝴蝶翅膀上的鳞状覆盖物内包含着一些被称为“光子晶体”（Photonic Crystals）的微小结构，而这和发光二极管中的微孔的作用机制非常类似。对此，研究人员之一的英国埃克赛特大学专家皮特表示：“（这些鳞状物）可以防止荧光光线在鳞状物内部被截留，同时也能防止光线向侧面发散出去。”
另外，这些鳞状物的下方也有一个专门的“镜子”，这与发光二极管中的微小的“镜子”作用非常相似。
报道说，此项研究被发表在最近一期的《科学》杂志上。 | 
