微纳米尺度红外光热膨胀效应及新型光热驱动方法研究

The effect of infrared laser-induced micro/nano photothermal expansion and the novel method of photothermal actuation

介绍了一种新型的基于非对称结构的光热微型驱动器.驱动器由两个宽细不同的薄悬臂组成.当红外激光照射在悬臂上时,宽窄悬臂的比表面积不同,导致其温度升高和伸长量不同,从而使驱动器产生偏转.建立了驱动器的热力学模型,并给出了偏转量的计算公式.使用准分子激光加工系统制作了一个长750μm的微驱动器样机,红外激光(998nm)作为驱动源,利用自制的控制监控系统进行了可行性试验,观察并测量了驱动器偏转量与红外激光功率的关系.结果表明,本驱动器在16mW的红外激光的驱动下,即可产生25.8μm的偏转量.利用光热膨胀的方法实现的驱动器制作简单,位移输出可调,无电磁干扰,易于集成,并可以实现远程控制,在微纳技术和MEMS领域具有广阔的应用前景.

This paper presents a novel asymmetric microactuator based on photo-thermal expansion. It has an asymmetric structure consisting of two thin expansion arms with different widths. When a beam of infrared laser irradiates the arms, the different increases in temperature and photo-thermal expansion controlled by the different rates of specific surface area causes a magnified lateral deflection. In the paper, the thermodynamic model is introduced, and the computing formula of lateral deflection is given. A prototype microactuator of 750 μm length has been manufactured by using the excimer laser micromaching system Optec Promaster with an infrared laser diode （998 nm） as the external power source to activate the microactuator. Then we carried out feasibility experiments by using a monitored control system made by our laboratory, and measured the relationship between the lateral deflection and laser power. The experiment results demonstrate that the deflection of the microactuator reached 25.8 μm at lfi mW infrared laser power. The photo-thermal microactuator has the advantages of simple structure, adjustable deflection, no electromagnetic interference, easy integrating and remote controlling. It will be quite useful for applications in the fields of micro/ nano-technology and micro-electro-mechanical systems （MEMS）.