微型化全像光學元件結合雙軸壓電翹板式致動器之 最佳化設計及凝血檢測研究應用

Abstract

近十年來，許多著重於微型化光學讀取模組搭配懸臂或壓電致動器之設計研究，面臨些許技術障礙，最主要由旋轉式搖臂致動器致動的微型化光學讀取模組產生偏斜致動，隨後引起離軸像差和劣化的光點品質及聚焦誤差訊號，此外，電磁驅動音圈馬達產生非致動方向的磁力導致循軌誤差及耗能。 本論文研究針對微型化全像光學讀取頭設計一雙軸式翹板致動器搭配雙層壓電片於懸臂前端，藉由電磁及壓電 “雙軸式” 聚焦驅動，有效減少了光學傾角的誤差及提高系統頻寬。並進行微型化全像光學讀取頭之光學元件、光學特性、封裝流程及其光學模擬光點品質及聚焦誤差訊號分析及實驗測試。本研究針對本光學模組設計一符合之雙軸翹板壓電致動器，建立三維致動器模型，以有限元素分析(FEM)軟體模擬結構模態及電磁場偶合靈敏度之最佳化分析，提高致動方向磁力及懸臂之聚焦與巡軌的共振頻率，再以尤拉-白努力方程式推導壓電片動態模型，並以最佳化理論做數值分析，實驗針對單雙軸差異，如系統頻譜響應、傾角誤差、橫向誤差、搭配光學讀取頭之聚焦誤差訊號做比較。 最後，本研究應用雙軸致動器及微型化全像光學讀取頭模組實現血液凝血檢測，藉由微型光學讀取系統之微小化、快速化與精密定位等特性，以635nm紅光雷射聚焦於鏡面上之全血血滴或血漿樣本，藉由反射光回授至光偵測器判別光強度大小，分析凝血酶原時間(prothrombin time, PT)，以達成凝血檢測應用的目標。血液凝血功能是檢測人體機制的重要依據，慢性疾病容易導致身體器官機能不正常，尤其是在重大手術時、糖尿病預防或是血栓栓塞，皆可由凝血機制得知。而判定血液凝固功能最直接方法即檢測凝血時間並配合國際訂定的INR值(International Normalized Ratio)，給予病人相關處方籤以達到控制病情。因此，快速、精確及家庭化的凝血檢測可適用於本研究之系統。

Many small-form-factor optical pickup unit based on the swing arm design utilize single piezoelectricity or slim plate of metal to perform focusing action. Technological obstacles to the use of rotary-type swing arm actuators to actuate optical pickup modules in small-form-factor (SFF) disk drives stem from a hinge’s skewed actuation subsequently inducts off-axis aberrations and deteriorates optical quality. This research describes a dual-stage seesaw-swivel actuator for optical pickup actuation. A bimorph bender made of piezoelectric materials, PbZrTiO3 (PZTs), is connected between the suspension and pickup head. The seesaw type actuator with PZT is a new driving mechanism used for swiveling the entire optical pickup heads devices. Additionally, the actuating force is increased within the limit of actuator size constraints by using an alternating multi segmented magnet array (MSMA) in biaxial voice coil motors (VCMs). The performance of the biaxial VCM is verified through simulation by finite-element methods, and the effectiveness is confirmed by parametric design optimization and experiments results. The configuration of the dual-stage seesaw swivel actuator has unique features including a rotary actuator for coarse and fine tracking and a seesaw arm for swiveling along a pivot instead of a hinge to permit a tilt focus movement. Besides, the tunable vibration absorber (TVA) unit is mounted on the seesaw swing arm to offer a balanced force to reduce vibrations in a focusing direction. Both PZT and TVA are designed to satisfy stable focusing operation operational requirements and compensate for the tilt angle or deformation of a measurement surface. The model equation of PZT bimorph is built and optimized by applying nonlinear programing theorem. Furthermore, the performances of optical module with swing arm-swivel actuation are experimentally evaluated to demonstrate the effectiveness of precise flying height positioning measurement method. Finally, HOE module with dual-stage seesaw arm actuator was utilized to evaluate blood coagulation in real time. The method involved assessing the decrease in transmitted light of the blood sample surface when the clotting is formed. The prothrombin time (PT) was measured by illumining and focusing a 635nm laser beam onto the sample. As the fibrinogen turned into non-solute fibrin, the transmitted efficiency and total intensity of the reflected light from the reflector changed. This method may provide a non-contact, label-free bio-detection process with less preparing time than other traditional methods. The results of PT measurements by proposed method were compared with those made by other optical sensors.