FORMABLE AND FLEXIBLE HAPTICS MATERIALS AND STRUCTURES

Abstract

A composition comprising: a piezoelectric polymer, and a binder. The composition may be printed to form a haptic component during a method of forming an electronic device.

Claims

1-23. (canceled)

24. A method of manufacturing an in-mould electronic (IME) component, the method comprising: preparing a blank; and thermoforming the blank, wherein preparing the blank comprises forming one or more structures on a thermoformable substrate, each structure formed by a method comprising: disposing a composition on a thermoformable substrate, and drying the composition at a temperature of from 20 to 150 C. for from 0.5 to 60 minutes, wherein the composition comprises: a piezoelectric polymer, and a binder.

25. The method of claim 24, wherein the one or more structures comprises a haptic structure, preferably an audio speaker or mechanical vibration device.

26. (canceled)

27. The method of claim 24, wherein the substrate comprises one or more of PolyEthylene Terephthalate (PET), Poly-Carbonate (PC), Paper, Poly(methyl methacrylate) (PMMA), PolyEthylene Nephalate (PEN), Polyimide (PI) and Thermoplastic polyurethane (TPU).

28. The method of claim 24, wherein the thermoforming is carried out at a temperature of from 140 C. to 210 C. and/or at a pressure of from 0.25 MPa to 0.4 Mpa and/or at a pressure ranging from 6 Mpa to 12 Mpa.

29. The method of claim 24, further comprising, after thermoforming, applying a layer of resin to the substrate using injection moulding, preferably wherein the resin comprises one or more of polycarbonate (PC), polyethylene terephthalate (PET), acrylonitrile butadiene styrene (ABS), polypropylene (PP), polyester, poly(methyl methacrylate) (PMMA), low density polyethylene (LDPE), high-density polyethylene (HDPE), polystyrene (PS) and thermoplastic polyurethane (TPU).

30. The method of claim 29, wherein the injection moulding is carried out at a temperature of from 170 to 330 C.

31. The method of claim 24, wherein preparing the blank further comprises forming one or more conductive layers and/or dielectric layers on the substrate and/or structure.

32-43. (canceled)

44. The method of claim 24, wherein the piezoelectric polymer comprises polyvinylidene fluoride (PVDF).

45. The method of claim 44, wherein the piezoelectric polymer comprises polyvinylidene fluoride-trifluoroethylene copolymer (PVDF-TrFe).

46. The method of claim 24, wherein the composition comprises, based on the total weight of the composition: from 5 to 95 wt. % piezoelectric polymer, preferably 15 to 70 wt. % piezoelectric polymer, more preferably from 20 to 60 wt. % piezoelectric polymer; and from 5 to 95 wt. % binder, preferably from 30 to 85 wt. % binder, more preferably from 40 to 80 wt. % binder.

47. The method of claim 24, wherein the binder comprises: a thermoplastic resin comprising a hydroxyl group, a crosslinking agent, and a solvent.

48. The method of claim 47, wherein the thermoplastic resin has a glass transition temperature of less than 100 C. and/or a softening point of less than 100 C.

49. The method of claim 47, wherein the thermoplastic resin comprises one or more of a polyurethane resin, a polyester resin, a polyacrylate resin, a polyvinyl ester resin, a phenoxy resin and a ketonic resin.

50. The method of claim 49, wherein the thermoplastic resin comprises, based on the total weight of the thermoplastic resin: from 20 to 60 wt. % polyurethane resin, preferably from 35 to 47 wt. % polyurethane resin, from 5 to 30 wt. % polyester resin, preferably from 13 to 19 wt. % polyester resin, and from 20 to 60 wt. % phenoxy resin, preferably from 34 to 51 wt. % phenoxy resin.

51. The method of claim 47, wherein the crosslinking agent comprises one or more of a melamine resin, an amino resin, a polyamine resin, an isocyanate, and a poly-isocyanate.

52. The method of claim 51, wherein the cross-linking agent comprises melamine formaldehyde.

53. The method of claim 52, wherein the melamine formaldehyde comprises hexamethoxymethyl melamine.

54. The method of claim 52, wherein the cross-linking agent further comprises isocyanate and/or polyisocyantate and/or blocked polyisocyanate.

55. The method of claim 47, wherein the binder comprises, based on the total weight of the binder: from 10 to 40 wt. % of the thermoplastic resin, preferably from 11 to 30.4 wt. % of the thermoplastic resin; from 0.5 to 12 wt. % of the crosslinking agent, preferably from 1.5 to 7.7 wt. % of the crosslinking agent; and from 40 to 85 wt. % solvent, preferably from 46.7 to 78.8 wt. % solvent.

56. The method of claim 47, wherein the binder further comprises a thermosetting resin, preferably comprising one or both of acrylic resin and epoxy resin; and a curing catalyst for curing the thermosetting resin, preferably for thermally curing the thermosetting resin and/or for UV curing the thermosetting resin.

Description

[0088] The invention will now be further described with reference to the following drawings in which:

[0089] FIGS. 1a, 1b and 1c are photographs of a touch pad formed using the composition of the present invention.

[0090] FIG. 2 shows the electrical response displayed on an oscilloscope screen when the touch pad of FIG. 1a was repeatedly pressed with a finger.

[0091] FIG. 3 shows oscilloscope screen shots of the force sense signal from a polymer based haptic integrated with capacitive touch switch.

[0092] FIG. 4 shows the detected force signal from a printed touch sensor.

[0093] The invention will now be further described with reference to the following example.

EXAMPLE

[0094] A two-electrode touch pad was prepared according to the following method. First a flexible polycarbonate film was provided. Onto the film was printed a conductive silver ink to form a bottom electrode. A composition according to the present invention in the form of an ink was then printed onto the bottom electrode to form a haptic layer, and onto the haptic layer was printed a conductive silver ink to form a top electrode. The inks were then cured in an over at a temperature of less than 120 C. The resulting touch pad is shown in FIG. 1a.

[0095] Two more two-electrode touch pads were prepared using a similar method. However, following curing, the touch pads were thermoformed at a temperature of from 150 to 180 C. The resulting thermoformed touch pads are shown in FIGS. 1b and 1c.

[0096] The touch pad of FIG. 1a was connected to an oscilloscope to monitor the electrical signal generated during experiments. During initial experiments, the central pad was repeatedly pressed with a finger to see if any electrical signal generated. To avoid grounding by the human body, an electrically insulating tape was pasted on top of the top electrode.

[0097] FIG. 2 shows the electrical response displayed on the oscilloscope screen when the touch pad was repeatedly pressed with a finger. No filter circuit was used between the touch pads and the oscilloscope. Therefore, multiple peaks are observed for each touch showing a natural response and natural damped vibrations as expected. The touch pads formed into 3D shapes (FIGS. 1b and 1c) also show performance similar to the flat sample (FIG. 1a). Extreme forming, where samples are stretched beyond the limits of the materials used to make them, may lead to degradation of performance or failure. Failure, for example, in conductive inks may be loss of conductivity while that in dielectric or haptics layer may be an increase in leakage current (loss of isolation).

[0098] FIG. 3 shows a typical electrical response from an active haptics layer under a capacitive touch pad manufactured in accordance with the present invention. In this case a known weight was placed on the touch pad. A response was recorded when the weight was quickly lifted. A variation in the response time was observed, as expected, because the weight is lifted manually. A similar response is observed when the weight is placed onto the sample. Manual nature of experiments means a variation in the applied stimulus rate/time, and hence, in observed response time. Polarity of the electrical signal is immaterial here because it depends on the order of the probe terminals.

[0099] FIG. 4 shows the total energy response of the haptics/sensor shown in FIG. 1a versus the applied force. The total energy response is calculated as the full integrated area under the response curve shown in FIG. 3. Taking this integration removes variation induced because of the manual experiment. Each data point is an average of a large number of measurements. Experiments done with different samples produce a similar response. The response signal increases with increasing applied force. This demonstrates that this structure can be used as force sensor. Alternately, the touch sensor switch can be used to turn on an electrical voltage and thus physically expand or contract the active haptics layer. An alternating voltage signal can be used to vibrate the stack at a preset frequency and send a sensory signal back to the object touching the pad.

[0100] The foregoing detailed description has been provided by way of explanation and illustration, and is not intended to limit the scope of the appended claims. Many variations in the presently preferred embodiments illustrated herein will be apparent to one of ordinary skill in the art and remain within the scope of the appended claims and their equivalents.