近年來，隨著多功能且輕薄的電子產品發展，使得零件漸漸朝向微小化，提升產品組裝的困難度，因此需發展微組裝技術。其中，微小物件之夾持是微組裝中最重要的一環，然而微小物件易因表面張力作用，使得在取放過程中附著於夾持具上，造成夾持位置的偏移，甚至因夾持力的不易控制，使夾持物件的表面產生磨損與髒污，這些問題將使產品的良率下降。有鑑於此，有人利用非接觸懸浮技術來實現非接觸式夾持系統，由於夾持具並不與物件實際接觸，克服在夾取過程中所產生的問題。其中，聲音懸浮技術具有不受漂浮物材質與形狀限制的特性，近年被廣泛地應用在光電、半導體、微機電製程、複合材料、與生物醫學等領域，由這些應用領域亦可知其發展性。
本研究係利用壓電致動器產生超音聲波，以實現非接觸式超音波夾持系統，提升傳統聲浮技術的懸浮力量及夾持穩定性，將可應用於開放空間之夾持。由於聲浮夾持系統包含超音波聲源與聲波之間的耦合，其理論分析較為複雜。因此本論文將建立壓電致動器的數學模型，描述其機電耦合的關係，並轉化成系統方塊圖，分析在高頻操作時的共振行及其特性響應。並且類比於一般的機電馬達系統方塊圖，提出系統參數鑑別之實驗架構，建立出壓電致動器的動態模型。
為了實現超音波聲浮夾持系統，本研究提出一套完整的設計流程，包含超音波聲源的設計，並由平面聲波原理求得達到共振聲場的操作條件，以達到足夠的懸浮力，之後根據近場的聲壓理論，計算出聲浮夾持系統內聲壓的分佈，藉此獲得懸浮位置與懸浮物密度等特性分析。而在之前的文獻中，由於在超音波量測上的一些限制，造成無法驗證理論分析的正確性，侷限非接觸夾持應用的發展。因此本論文也提出非接觸式量測的理論，不僅可量測出所設計的夾持系統之懸浮特性，並由實驗結果顯示，本論文所提出之設計流程與理論模型，具可行性與實用性。因此根據所提出的設計流程，實現一套傾斜式聲浮夾持系統，藉由調整壓電致動器的擺設角度與距離，可控制懸浮物的位置，達到平面的運動，並且藉由傾斜擺置的設計，可抵抗外界環境的干擾，擴展聲音懸浮技術的應用領域。

Recently, miniature customer electronic products with multi-functional features require the continuous reduction in the average size of the micro-components, which makes assembly become a difficult task in the micro-manipulation process. Standing-wave acoustic levitation technology, which is advantageous for levitating various shapes and materials of micro- components, has been developed to avoid damage or contamination in the pick-up and release procedure, and has been widely used in industrial applications such as optoelectronics, semiconductors, composite materials, and biomedical for its flexibility.
This paper aims to provide an alternative method to determine the characteristics of a piezoelectric transducer, which is employed to generate the high intensity acoustic wave for increasing the performance of the acoustic levitation structure. A block diagram approach is proposed to analyze the dynamic characteristics of a thickness-mode piezoelectric transducer at its resonance frequency. Based on the feedback loop framework, the input-output relations of the electromechanical interaction of the transducer are described in terms of linear block diagram models. Combined with the near-field acoustic equation, a theoretical model of the acoustic tweezers is derived such that the pressure distribution of the tweezers can be calculated to determine the trapped position.
In addition, a design procedure is proposed to determine the operation conditions for the resonance acoustic field by acoustic plane-wave analysis, and then a non-contact acoustic tweezers is implemented for suspending small objects of millimeter dimension and low density in the open-space environment without direct mechanical contact, such as a PVC tube, small metal pieces, and mosquitoes. To monitor the levitating behaviors of the proposed acoustic tweezers, non-contact measurement principles are proposed such that a parallel light with a CCD camera is adopted to measure the levitating position without the scattering problem, and a laser interferometer is employed to non-contact measure the acoustic pressure without acoustic interference. Based on these behavior measurements, a significant theoretical-measurement agreement to implement the acoustic tweezers by the proposed model and design procedure is demonstrated.
Hence, a quasi-standing wave field by crossing two ultrasonic waves with an inclined angle can be designed to develop a novel acoustic tweezers without the need for a reflector instrument. The proposed acoustic tweezers demonstrates the capability of 2-D manipulation by adjusting the inclined angle and the relative distance of the two transducers, respectively. In addition, due to the horizontal arrangement of the two transducers with an inclined angle, the resistance ability from the external environment disturbances can be improved to extend the acoustic levitation applications.

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