Design and Fabrication of Fresnel Lens and ZnO Thin-Film Transducer

Abstract

A four-level Fresnel lens and piezoelectric transducer were fabricated as an ejector using focused ultrasonic energy. The influence of the fabrication parameters on the profile of the focusing lens was investigated. Highly c-axis (002)-oriented ZnO films were successfully deposited on Pt (annealed)/Ti/SiO2/Si substrates under reasonable conditions, such as RF power of 178 W, substrate temperature of 380 °C, deposition pressure of 10 mTorr, and Ar:O2 gas flow ratio of 50%. These conditions were applied and confirmed through investigating the influence of deposition parameters on the properties of ZnO films.

Using SiO₂ Hard Mask for Fabrication of Micro Fresnel Focusing Lens for Ultrasonic Ejectors

“…According to our design, the maximum radial distance and the step height of a 100 MHz focusing lens are obtained with r16 = 244 µm and h = 4.55 µm, respectively. Likewise, the maximum radial distance and step height of a 200 MHz focusing lens are 122 µm and 2.27 µm, respectively [15]. The designated Fresnel lens is described as Fig.…”

Wideband Multimode Transducer Consisting of c-Axis Tilted ZnO/c-Axis Normal ZnO Multilayer

“…Therefore, the c-axis tilted ZnO layer is grown instead of the c-axis normal layer, because the sputtered particles tilt to the substrate plane. 24,25) The ZnO transducer with the c-axis tilted ZnO/c-axis normal ZnO multilayer thus can be fabricated continuously without changing the conditions during the deposition.…”

Development of a Long-Focal-Range Annular Array Ultrasonic Transducer

“…Annular array transducers have already been developed for nondestructive testing, medical uses, and industrial applications. [1][2][3][4][5][6][7][8] Various lens types, such as the curved type, [2][3][4][5][6] flat type, 7) and step height type, 8) have been developed to obtain effective focusing. They consist of a number of equal-area elements and allow the focal point to be shifted by electrical control.…”