Localized multimodal electromechanical polymer transducers
A localized multimodal haptic system includes one or more electromechanical polymer (EMP) transducers, each including an EMP layer, such as an electrostrictive polymer active layer. In some applications the EMP transducer may perform an actuator function or a sensor function, or both. The EMP polymer layer has a first surface and a second surface on which one or more electrodes are provided. The EMP layer of the EMP actuator may be 5 microns thick or less. The EMP transducers may provide local haptic response to a local a stimulus. In one application, a touch sensor may be associated with each EMP transducer, such that the haptic event at the touch sensor may be responded to by activating only the associated EMP transducer. Furthermore, the EMP transducer may act as its own touch sensor. A variety of haptic responses may be made available. The EMP transducers may be used in various other applications, such as providing complex surface morphology and audio speakers.
1. A system comprising one or more electromechanical polymer (EMP) transducers, each EMP transducer comprising:
a plurality of EMP layers each having a first surface and a second surface separated by a thickness that is less than 10 microns, each EMP layer being formed out of an electrostrictive polymer; and
a plurality of electrodes each provided adjacent one or more of the EMP layers, wherein the electrodes are connected to provide or to sense, in each EMP layer, a voltage across the first surface and the second surface, wherein the EMP transducer generates an acceleration of greater than 0.5 Gs under an electric field.
2. The system of claim 1 , wherein each EMP transducer is independently controlled or sensed.
3. The system of claim 1 , wherein at least one of the EMP layers is stretched.
4. The system of claim 3 , wherein the EMP layer is stretched biaxially.
5. The system of claim 1 , wherein the electric field is an AC electric field which causes the EMP transducer to vibrate.
6. The system of claim 5 , wherein the EMP transducer vibrates at a frequency proportional to the frequency of the AC electric field.
7. The system of claim 1 , further comprising a substrate having a surface to which one or more of the EMP transducers are attached, wherein the provided voltage creates an electric field which causes the attached EMP transducers to deform the surface in response to the applied electric field.
8. The system of claim 1 , wherein the EMP layers in each EMP transducer are of different thicknesses and sizes.
9. The system of claim 8 , wherein the EMP transducers have EMP layers that are of different thicknesses.
10. The system of claim 1 , wherein the EMP transducers are arranged regularly on a surface.
11. The system of claim 10 , wherein the EMP transducers are arranged in an array.
12. The system of claim 10 , wherein the EMP transducers are provided at selected positions of a grid.
13. The system of claim 10 , wherein the EMP transducers are positioned at selected corners of a regular polygon.
14. The system of claim 1 , wherein EMP transducer comprises multiple component transducers stacked together, the component transducers being of a different size, a different layer thickness, or a different number of EMP layers relative to each other.
15. The system of claim 1 , wherein each EMP transducer has a response latency of less than 40 milliseconds.
16. The system of claim 1 , wherein each EMP transducer has a decay me of less than 40 milliseconds.
17. The system of claim 1 , wherein the EMP layer is between 0.1 um to 10 um.
18. The system of claim 17 , wherein the EMP layer is 5 microns thick or less.
19. The system of claim 17 , wherein the EMP layer is 3 microns thick or less.
20. The system of claim 1 , further comprising a substrate bonded to the EMP transducers.
21. The system of claim 20 , wherein the substrate is bonded to the EMP transducers by an adhesive.
22. The system of claim 20 , wherein the substrate is bonded to the EMP transducers by thermal lamination.
23. The system of claim 20 , wherein the substrate is rigid.
24. The system of claim 20 , wherein the substrate is flexible.
25. The system of claim 1 , wherein the EMP transducer is transparent.
26. The system of claim 1 , wherein the EMP transducer is semitransparent.
27. The system of claim 1 , wherein the EMP transducer is opaque.
28. The system of claim 1 , further comprising a controller providing individual control signals to the electrodes of each EMP transducers.
29. The system of claim 28 , wherein the EMP transducers are positioned in predetermined locations such that the EMP transducer are controlled by the individual signals to function as a phased array of actuators to focus the haptic responses of the EMP transducers.
30. The system of claim 28 , wherein the EMP transducers are positioned at predetermined locations and controlled by the individual signals to achieve pre-determined displacements at the predetermined locations.
31. The system of claim 30 , wherein one of the EMP transducers achieves an acceleration magnitude of greater than 0.5 G.
32. The system of claim 1 , wherein the electrostrictive polymer comprises one or more polymers selected from the group consisting of a polymer, copolymer, or terpolymer of vinylidene fluoride.
33. The system of claim 1 , wherein the electrostrictive polymer comprises a polymer selected from a group of polymers consisting of: P(VDF x -TrFE y -CFE 1-x-y ) (CFE: chlorofluoroethylene), P(VDF x -TrFE y -CTFE 1-x-y ) (CTFE: chlorotrifluoroethylene), Poly(vinylidene fluoride-trifluoroethylene-vinylidede chloride) (P(VDF-TrFE-VC)), poly(vinylidene fluoride-tetrafluoroethylene-chlorotrifluoroethylene) (P(VDF-TFE-CTFE)), poly(vinylidene fluoride-trifluoroethylene-hexafluoropropylene), poly(vinylidene fluoride-tetrafluoroethylene-hexafluoropropylene), poly(vinylidene fluoride-trifluoroethylene-tetrafluoroethylene), poly(vinylidene fluoride-tetrafluoroethylene-tetrafluoroethylene), poly(vinylidene fluoride-tri fluoroethylene-vinyl fluoride), poly(vinylidene fluoride-tetrafluoroethylene-vinyl fluoride), poly(vinylidene fluoride-trifluoroethylene-perfluoro(methyl vinyl ether)), poly(vinylidene fluoride-tetrafluoroethylene-perfluoro (methyl vinyl ether)), poly(vinylidene fluoride-trifluoroethylene-bromotrifluoroethylene, polyvinylidene), poly(vinylidene fluoride-tetrafluoroethylene-chlorofluoroethylene), poly(vinylidene fluoride-trifluoroethylene-vinylidene chloride), and poly(vinylidene fluoride-tetrafluoroethylene vinylidene chloride), where x has a value in the range between 0.5 and 0.75, y has a value in the range between 0.45 and 0.2.
34. The system of claim 1 , wherein the elecctrostrictive polymer comprises a P(VDF-TrFE-CFE) or P(VDF-TrFE-CTFE) terpolymer.
35. The system of claim 1 , wherein the electrostrictive polymer comprises a high energy electron irradiated P(VDF-TrFE).
36. The system of claim 1 , wherein the electrostrictive polymer comprises a blend of electrostrictive polymers with PVDF and PVDF copolymers.
37. The system of claim 36 , wherein the blend includes one or more of P(VDF-CTFE), P(VDF-HFP), P(VDF-CFE), P(VDF-TrFE), and P(VDF-TFE) polymers.
38. The system of claim 1 , wherein the EMP transducer acts as a temperature change sensor in response to variations in temperature in its environment.
39. The system of claim 1 , wherein the EMP transducer cools in response to activation signals in the electrodes.
40. The system of claim 39 , wherein the cooling in the EMP transducer is used in a haptic application to provide tactile feedback to a user.
41. The system of claim 1 , further comprising a force receiving surface structurally connected with the EMP layers for transmitting an external force to the EMP layers.
42. The system of claim 41 , further comprising a substrate bonded to one side of one of the EMP transducers, and wherein the force receiving surface being provided on the side of the EMP sensor opposite to the side of the EMP sensor bonded to the substrate.
43. The system of claim 41 , wherein the force receiving surface is provided on a compliant metal plate.