System and method for manipulating objects in a computational acoustic-potential field
A novel system and method based on three-dimensional acoustic-manipulation technology is disclosed. By changing the distribution of an acoustic-potential field generated by ultrasonic phased arrays, objects can be levitated and animated. Various distributions of acoustic-potential fields can be generated in accordance with the present invention, including acoustic-potential fields having arbitrary shapes, including any three-dimensional shapes. One or more ultrasonic phased arrays surrounding a workspace can be used to generate standing waves of various shapes to provide the acoustic-potential fields. Objects can be suspended at the nodes of the acoustic-potential field so that the ultrasound distribution (i.e., the desired arbitrary shape) is visualized. The system and method can be used to realize floating screen or mid-air raster graphics, mid-air vector graphics, and interaction with levitated objects. The system and method can also be used in other applications, including cleaning applications.
1. A method of generating an acoustic-potential field using a pair of phased arrays opposite each other, each phased array comprising a plurality of ultrasonic transducers arranged in columns, the method comprising the steps of:
receiving holographic information representative of a desired acoustic-potential field;
identifying target coordinates for a plurality of focal points based on the holographic information;
targeting the focal points with each column of ultrasonic transducers;
determining phase information between each of the focal points and each ultrasonic transducer within each column of ultrasonic transducers; and
using the phase information to generate ultrasonic waves from the phased arrays of ultrasonic transducers to form standing waves at the focal points.
2. The method of claim 1 , wherein the plurality of focal points are provided at arbitrary positions in three-dimensional space.
3. The method of claim 1 , wherein the standing waves are formed in three dimensions.
4. The method of claim 1 , further comprising the step of suspending objects in nodes of the standing waves.
5. The method of claim 1 , further comprising the step of visualizing the desired acoustic-potential field.
6. The method of claim 5 , wherein the visualizing step comprises the step of suspending objects in nodes of the standing waves.
7. The method of claim 1 , involving a plurality of phased arrays of ultrasonic transducers, further comprising the steps of:
orienting the holographic information relative to a spatial position of each of the plurality of phased arrays of ultrasonic transducers;
identifying target coordinates for the plurality of focal points based on the oriented holographic information for each phased array of ultrasonic transducers;
targeting the focal points with each column of ultrasonic transducers;
determining the phase information between each of the focal points and each ultrasonic transducer within each column of ultrasonic transducers; and
using the phase information to generate ultrasonic waves from each phased array of ultrasonic transducers to form standing waves at each of the plurality of focal points.
8. The method of claim 1 , wherein the step of targeting the focal point targets a separate focal point with each column of ultrasonic transducers in accordance with the equation Δt ij =(l 0j −l ij )/c, wherein
Δt ij represents a time delay for the application of a drive signal to an ultrasonic transducer in a column of ultrasonic transducers relative to the application of a drive signal to a reference ultrasonic transducer for that column,
l 0j represents a distance from the focal point targeted by that column of ultrasonic transducers to the reference transducer for that column,
l ij represents the distance from the focal point targeted by that column to a non-reference ultrasonic transducer for that column, and
c represents the speed of sound in air.
9. A system for generating an acoustic-potential field using a pair of phased arrays opposite each other, each phased array comprising a plurality of ultrasonic transducers arranged in columns, the system comprising:
a calculator configured to receive holographic information representative of a desired acoustic-potential field, identify target coordinates for a plurality of focal points based on the holographic information, target the focal points with each column of ultrasonic transducers, and determine phase information between each of the focal points and each ultrasonic transducer within each column of ultrasonic transducers; and
a generator configured to use the phase information to generate ultrasonic waves from the phased arrays of ultrasonic transducers to form standing waves at the focal points.
10. The system of claim 9 , wherein the plurality of focal points are provided at arbitrary positions in three-dimensional space.
11. The system of claim 9 , wherein the standing waves are formed in three dimensions.
12. The system of claim 9 , wherein objects are suspended in nodes of the standing waves.
13. The system of claim 9 , further comprising a visualizer configured to visualize the desired acoustic-potential field.
14. The system of claim 13 , wherein the visualizer suspends objects in nodes of the standing waves.
15. The system of claim 9 , further comprising a plurality of pairs of phased arrays of ultrasonic transducers, the phased arrays in each pair of phased arrays disposed opposite each other, wherein the calculator orients the holographic information relative to a spatial position of each of the plurality of phased arrays of ultrasonic transducers, identifies target coordinates for the plurality of focal points based on the oriented holographic information for each phased array of ultrasonic transducers, targets the focal points with each column of ultrasonic transducers, and determines the phase information between each of the focal points and each ultrasonic transducer within each column of ultrasonic transducers, and the generator uses the phase information to generate ultrasonic waves from each phased array of ultrasonic transducers to form standing waves at each of the plurality of focal points.