Figure 1.
Potential energy distribution of ultrasonic standing wave.
This figure is obtained based on Eqs. (1) and (2). The horizontal axes x/w and z/λ are the radial and axial directions of the beam, respectively. The vertical axis is the normalized potential energy. The gradient of this distribution gives the force on a small particle.
Figure 2.
(Left) The phased array modules are operated by a computer via USB. (Middle) Each driving circuit board consists of three components; USB I/F, FPGA, and Driver ICs. (Right) Each phased array module has 285 ultrasonic transducers.
Figure 3.
Illustration and photograph of system setup.
The size of system is 520(height)×520 mm(width)×250 mm(depth). The focal point is set in the center of workspace. The labels of axis are shown in the figure: x-axis and z-axis are parallel to the device plane and y-axis is vertical to the device plane. We inserted the particles at the third node of beams that is parallel to x-axis in the stability experiments.
Figure 4.
(Left) Levitation and manipulation of particles with the vertical setup shown in Figure 3. (Right) Scooping up and holding particles with the horizontal setup in which all the ultrasonic beams are horizontally radiated.
Figure 5.
Results of stability experiments on different sizes of particles.
The horizontal axis shows the maximum acceleration (cm/s2) within back-and-forth motion. The blue, red, and green lines show the results of 0.6 mm, 1.0 mm, and 2.0 mm, respectively. (Left) The vertical axis shows the average number of times (the duration divided by the periodic time). (Right) The vertical axis shows the average duration of suspension [s]. Both show the same experimental results.
Figure 6.
Results of stability experiments on different directions of movement.
The horizontal axis shows the maximum acceleration (cm/s2) within back-and-forth motion. The green, blue, red lines show the results of along x-, y-, and z-axes. (Left) The vertical axis shows the average number of times (the duration divided by the periodic time). (Right) The vertical axis shows the average duration of suspension [s]. Both show the same experimental results.