Research and Development of Photo-sensitive Materials for Spatial Modulation of Flexible Structures

• Main Authors: Kuan-Ting Chen, 陳冠廷
• Other Authors: 李世光
• Format: Others
• Language: en_US
• Published: 2012
• Online Access: http://ndltd.ncl.edu.tw/handle/29621621348735267132

博士 === 國立臺灣大學 === 工程科學及海洋工程學研究所 === 100 === Optical field modulation has been used in many applications in recent years, such as optical tweezers, sensors, actuators, light dependent resistor and piezo-phototronic devices. Optical tweezers can generate forces in approximately the pN range. Lead zirconate titanate (PZT) is a piezoelectric material that has been investigated for applications, such as electromechanical actuators, sensors, and energy generators. PZT typically generates output forces in the range of mN to N. If the spatial mode shapes and output signals of PZT could be modulated for specific applications and linked with optical inputs, then the magnitude of the output force could be modulated by more than nine orders of magnitude compared with optical tweezers. This thesis proposed the innovation of optically modulated PZT sensors/actuators and developed the proposed device by integrating photosensitive materials with PZT. In addition, the applications of these materials were also explored and discussed. This work represents the first time that PZT sensors/actuators have been controlled using optical inputs. The optically modulated PZT actuators developed here have great potential for applications, including the manipulation of nano- and micro-particles by controlling the spatial mode shapes of PZT. Photosensitive materials are critical components for the design of optically modulated PZT sensors/actuators. Here, we propose two new photosensitive materials for integration with PZT, (1) a liquid crystal-spiropyran mixture (LC/SP) and (2) titanium oxide phthalocyanine (TiOPc). The impedance variation ratios of LC/SP mixture and TiOPc are 0.3 and 0.01 after UV and visible light irradiation respectively. The different properties of these photosensitive materials affect the device performance and can be applied for different applications. The electric properties of the LC/SP mixture and TiOPc are thus discussed in detail in terms of their suitability for PZT integration. The LC/SP mixture and TiOPc were used as the spatially modulated electrode of PZT in order to enable optical controllability. This thesis proposes an optical modal sensor system composed of an optically modulated PZT sensor for one-dimensional vibration sensing. Based on this optically controllable modal sensor system, mode 1 and mode 2 sensors could be implemented and exchanged in situ in real time using different optical images and irradiation times. These optical modal sensor systems based on LC/SP mixtures and TiOPc have high potential for adaptive vibration control systems and two-dimensional vibration control. The performance of optically modulated PZT actuators based on LC/SP mixtures and TiOPc were also discussed and investigated in detail. The successful implementation of the DC effect allowed us to control the deformation using the optically modulated PZT actuator, which was tailored in situ in real time with different optical images. This technology has great potential for applications, such as deformable mirrors and microfluidic control. Finally, this thesis explored and discussed various applications of optically modulated PZT sensors/actuators based on LC/SP mixtures and TiOPc. The output force and mode shapes of PZT sensors/actuators were modulated by introducing different optical images. The results strongly suggest that the materials developed in this thesis can perform well as optically modulated PZT sensors/actuators suitable for a variety of practical applications.