Three-dimensional variable-focus liquid lens using acoustic radiation force
Three-dimensional variable-focus liquid lens using acoustic radiation force
复制标题
利用声辐射力的三维可变焦液体透镜
DOI：
10.1109/tuffc.2011.2134
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发表时间：
2011
期刊：
影响因子：
--
通讯作者：
R. Isago and K. Nakamura
中科院分区：
文献类型：
--
作者：
D. Koyama;R. Isago and K. Nakamura
制作了一种具有轴向和径向可调焦点的液体透镜。我们一直在开发一种变焦液体透镜，它采用声辐射力，不包含任何机械运动部件。我们的液体镜片比传统的机械镜片更紧凑，反应更快。通过调幅(AM)信号激励，实现了1 kHz聚焦的快速扫描。液体透镜由一个内径为10 mm、厚度为3 mm的圆柱形丙烯酸池、两种不同折射率的不相容液体(水和硅油)和一个四电极的环形压电锆钛酸铅换能器组成。油水界面起到透镜表面的作用，它可以被换能器产生的声辐射力变形；这使得透镜能够充当可变焦距透镜。用光学相干层析技术观察了油水界面的变化。通过光线跟踪模拟计算了激光通过透镜的光路。通过控制PZT电极的输入电压，可以实现油水界面的三维变形和焦点的变化。当输入电压为45V，频率为1.9 MHz时，两个电极的径向位移角约为3°。利用高速相机对该透镜的动态性能进行了研究。具有相位差的AM信号的激励使半球状水滴振荡，使得焦点可以在轴向和径向进行扫描。
A liquid lens was fabricated with a focal point that can be varied in the axial and radial directions. We have been developing a variable-focus liquid lens that employs acoustic radiation force and does not contain any mechanical moving parts. Our liquid lens is more compact and has a faster response than conventional mechanical lenses. Rapid scanning of its focus at 1 kHz has been realized by excitation with an amplitude-modulation (AM) signal. The liquid lens consists of a cylindrical acrylic cell (inner diameter: 10 mm; thickness: 3 mm), two immiscible liquids with different refractive indices (water and silicone oil), and an annular piezoelectric lead zirconate titanate transducer with four electrodes. The oil-water interface functions as a lens surface and it can be deformed by the acoustic radiation force generated by the transducer; this enables the lens to act as a variable-focus lens. The variation of the oil-water interface was observed by optical coherence tomography. The laser beam path through the lens was calculated by ray-tracing simulations. The oil-water interface could be deformed and its focal point could be varied in three dimensions by controlling the input voltages of the PZT electrodes. The displacement angle in the radial direction was approximately 3° when two of the electrodes were excited by an input voltage of 45 V at a frequency of 1.9 MHz. The dynamic performance of the lens was investigated using a high-speed camera. Excitation by AM signals with a phase difference caused the hemispherical water droplet to oscillate, enabling the focus to be scanned in the axial and radial directions.