将LED设计成可穿戴电子产品

　　将LED设计成可穿戴电子产品

　　GaN更高的效率被用于可穿戴和能量收集设计的低功率指示灯。本文着眼于最新的LED技术如何在超低功耗系统中提供重要反馈。

　　氮化镓（GaN）是一种非常有趣的能量收集系统材料。3.5电子伏特的带隙本身以及建筑发光LED器件和高电子迁移率和更高的效率比硅让这些LED运行在较低的电流，开放的超低功耗的应用程序，可以通过提供能源的环境动力。GaN不仅是发光二极管的一种令人兴奋的材料，而且还有研究如何将这种材料也用作压电装置，以从运动中产生动力本身。这两种趋势正在引导GaN进入可穿戴和医疗电子领域的令人兴奋的新领域。

　　传统上很难在体积上取得成本效益，因为GaN结构的衬底是碳化硅（碳化硅）或蓝宝石来处理器件所能产生的热量。最近的发展已经取代了低成本的硅衬底，允许使用标准CMOS设备和硅晶片，从而大幅降低氮化镓基LED的成本。这就打开了在柔性衬底和可穿戴设计中使用这种低功率LED的可能性。

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　　The key issue for energy-harvesting applications is of course the power consumption. However， as these are high-brightness LEDs， the devices can be reduced in both size and power and still provide light for a range of wearable designs such as system monitors， and even as decoration in the material.

　　Pure GaN LEDs are at the UV and blue end of the spectrum and were originally used as the laser in Blu-ray systems， but can be doped with Indium and aluminum to generate green and white light. This makes use of the higher electron mobility and band gap of GaN and provides a range of colors for the LEDs. These can be powered by energy harvested from movement via vibration or solar cells. The vibration energy from movements can be captured by piezo electric devices， such as the Mide V22B， which feed into a power management sub-system that either provides the power directly to the LEDs or， more commonly， charges a battery as a store for the energy.