Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7137042 | Sensors and Actuators A: Physical | 2014 | 10 Pages |
Abstract
High frequency (>15Â MHz) ultrasound imaging is capable of producing high spatial resolution B-mode and color Doppler images for the efficient diagnosis of ocular diseases. However, commercial high frequency ultrasound imaging systems cannot currently provide its full capability for ophthalmic applications because either single element or annular array transducers are used in conjunction with mechanical scanning. To overcome the current limitations, 15Â MHz 128-element linear array transducers were developed, which are suitable to cover the whole eye from the eyelid in anterior segment to orbital fundus in posterior segment. To achieve the highest electromechanical coupling coefficient, 2-2 piezo-composite was designed and fabricated as an active layer. For the design, the simple model of the thickness-mode oscillation was derived and used in the 1-D model simulator such as PiezoCAD. Also, the usability of the simple model was verified by comparing its simulation results with those by finite element model-based PZFlex. In addition, easy fabrication procedure for the high frequency 2-2 piezo-composite arrays was proposed. In performance evaluation, the pulse-echo response of a representative composite element showed the center frequency of 14.4Â MHz and the â6Â dB fractional bandwidth of 69.4%. Measured insertion loss was achieved higher than â33.9Â dB and crosstalk level between elements less than â30Â dB. From the evaluation results, it is expected that the linear array transducer developed using the proposed design and fabrication methods can provide a potential alternative for high frequency ophthalmic imaging with the desired capability.
Related Topics
Physical Sciences and Engineering
Chemistry
Electrochemistry
Authors
Jung Hyui Cha, Jin Ho Chang,