Design and Development of High-Speed Resonant Scanner with Piezo-electric Buzzer
Date Issued
2015
Date
2015
Author(s)
Cheng, Yuo-Po
Abstract
Along with the development of biomedical technology, MEMS processing, and micro-machining, the high resolution and dynamic measuring ability technology for sample profile measurement has become the receiving attention field in recent years. Profile measurement system consists of two major parts of the positioning unit and the optical measurement unit. The positioning unit is applied to localize the position in the plane. The optical measurement unit is employed to detect the height information of the sample surface. Therefore, the profile measurement system can build the sample surface profile by scanning a region of the sample. This thesis demonstrates that the piezoelectric buzzer as the core component is utilized to design a high-speed resonant scanner. The astigmatic optical pick-up head measures the height of the sample surface. Integrating the high-speed resonant scanner and astigmatic optical pick-up head, the profile measurement system becomes compact and has a high-speed scanning capability. High-speed resonant scanner constructs with a coplanar design, which integrates the fast-axis and slow-axis in the same plane with the brass board of the piezoelectric buzzer as a parallel guide mechanism. The fast-axis operated at its resonant frequency can increase the scanning speed and amplify the stroke. The piezoelectric buzzer applying inverse piezoelectric effect drives a large stroke in open-loop control. The closed-loop scan mode is another function if applying the direct piezoelectric effect on the buzzer. Besides, this thesis also demonstrates that the theory and finite element simulation are employed to enhance the dynamic performance of the scanner. In the thesis, we develop a two-dimensional coplanar high-speed resonant scanner with buzzers. The dimensions of the scanner are 47 mm in length, 33 mm in wide, and 20 mm in height. The total weight of the scanner is 21.40 g. The scanner has maximum actuation strokes of 140 μm and 5 μm in the fast-axis and slow-axis, respectively. The non-linearity of the axes are 5.90% in fast-axis and 3.07% in slow-axis. Furthermore, the resonant frequency of the fast-axis without loading is up to 675 Hz. Combining the resonant scanner with astigmatism Blu-ray pick-up head, the profile measurement system can use both open-loop control and close-loop control to get the surface profile of the standard sample TGZ3 successfully.
Subjects
Piezo buzzer
Coplanar structure
Resonance
High-speed
Astigmatic pick-up head
Profile scanning
Piezo actuator
Piezo sensor
Type
thesis
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