Metamaterials and acoustic lenses in haptic systems
The properties of metamaterials are derived both from the inherent properties of their constituent materials and from the geometrical arrangement of those materials. Metamaterials may be stacked or otherwise manipulated to transform substantially monochromatic signal into a second signal having a desired amplitude and phase. Metamaterials may be used with acoustic devices to create haptic feedback with desired properties or to transform the shape of certain devices. Metamaterials may be used in rotating devices with openings that transform a monochromatic signal into a non-monochromatic signal.
1. A method comprising:
generating a substantially monochromatic signal having a first phase and a first amplitude;
transmitting the substantially monochromatic signal through a metamaterial system, wherein the metamaterial system has a plurality of structural elements defining a first elongated path through the metamaterial system and wherein the metamaterial system comprises stacked metamaterial layers and wherein the stacked metamaterial layers sample a curve in the complex plane;
actuating the plurality of structural elements so as to define a second elongated path through the metamaterial system, wherein the second elongated path has a different length that the first elongated path;
wherein the substantially monochromatic signal is transformed within the metamaterial system into a second signal having a second amplitude and a second phase.
2. The method as in claim 1 , wherein the plurality of structural elements comprise teeth in a tortuous path design and wherein the second phase is different than the first phase.
3. The method as in claim 1 , wherein the plurality of structural elements comprise layers of mesh and wherein the second amplitude is different than the first amplitude.
4. The method as in claim 1 , wherein the change from the first amplitude to the second amplitude and the change from the first phase and the second phase are encoded in a complex phasor.
5. The method as in claim 1 , wherein the metamaterial system comprises a Helmholtz resonator that is actuated by opening a hole in a chamber producing effectively an amplitude increase.
6. The method as in claim 1 , wherein the stacked metamaterial layers sample the complex plane of phasors using a logarithmic spiral of coefficients reachable through digital control.
7. The method as in claim 1 , wherein the stacked metamaterial layers conduct a sampling of the complex plane through an irrational step using the golden angle in order to find the most efficient packing of coefficients in the complex plane.
8. The method as in claim 1 , wherein the second signal is focused at a control point to produce haptic effects.
9. The method as in claim 1 , wherein the second signal is focused at a control point to produce parametric audio.
10. The method as in claim 1 , wherein the second signal is focused at a control point to cause an object at the control point to levitate.
11. An apparatus comprising:
a first rotating teeth structure comprising:
a first spindle;
a first rotating element having a first metamaterial cell, wherein the first metamaterial cell is capable of rotating about the first spindle in a first rotating direction;
a first set of gear teeth at the circumference of the first rotating structure that is capable of rotating about the first spindle in a first rotating direction;
a first opening in the first rotating element capable of transforming a monochromatic signal into a non-monochromatic signal while the first rotating element is rotating the first metamaterial cell.
12. The apparatus as in claim 11 , further comprising:
a second rotating teeth structure comprising:
a second spindle;
a second rotating element having a second metamaterial cell, wherein the second metamaterial cell is capable of rotating about the second spindle in a second rotating direction;
a second set of gear teeth at the circumference of the second rotating structure that is capable of rotating about the second spindle in a second rotating direction;
a second opening in the second rotating element capable of transforming a monochromatic signal into a non-monochromatic signal while the second rotating element is rotating the second metamaterial cell.
13. The apparatus as in claim 12 , wherein the first set of gear teeth interface with the second set of gear teeth and wherein the first rotating direction is opposite to the second rotating direction.
14. The apparatus as in claim 13 , further comprising a third opening in the second rotating element capable of transforming a monochromatic signal into a non-monochromatic signal while the second rotating element is rotating the second metamaterial cell;
wherein the first rotating teeth structure is smaller than the second rotating teeth structure;
and wherein the ratio of the circumference of the first rotating structure and the circumference of the second rotating structure is approximately an integer.