Integrated piezoelectric cantilever actuator and transistor for touch input and haptic feedback applications

• US 10,061,386 B2
• Filed: 06/03/2016
• Issued: 08/28/2018
• Est. Priority Date: 06/26/2015
• Status: Active Grant

• Current Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Original Assignee: SABIC Global Technologies BV (Government of Saudi Arabia)
• Inventors: Frescas, Jesus Alfonso Caraveo, Al-Howaish, Ibrahim, Almadhoun, Mahmoud M., Bella, Redha
• Primary Examiner(s): DOUGHERTY, THOMAS M
• Application Number:
  US15/303,855
• Publication Number:
  US 20180120938A1
• Time in Patent Office: 816 Days
• Field of Search: None
• CPC Class Codes: G06F 1/163 Wearable computers, e.g. on a belt
• CPC Class Codes: G06F 3/014 Hand-worn input/output arrangements, e.g. data gloves
• CPC Class Codes: G06F 3/016 Input arrangements with force or tactile feedback as computer generated output to the user
• CPC Class Codes: H10N 30/2042 Cantilevers, i.e. having one fixed end
• CPC Class Codes: H10N 30/306 Cantilevers
• CPC Class Codes: H10N 39/00 Integrated devices, or assemblies of multiple devices, comprising at least one piezoelectric, electrostrictive or magnetostrictive element covered by groups H10N30/00 – H10N35/00

Abstract

User feedback may be generated and user input received through a single semiconductor component integrated into the electronic device. The single semiconductor component may include a piezoelectric cantilever actuator integrated with a transistor, such as a thin-film transistor, such that the actuator is electrically isolated from the transistor but mechanically attached to the transistor. One manner of integration is to extend a piezoelectric thin film of the actuator into a gate electrode stack of the transistor. The cantilever actuator may be controlled to provide haptic feedback. Separate from, and possibly simultaneously with the control of the cantilever actuator, user input may be received through the transistor integrated with the cantilever actuator.

Claims

1. An apparatus, comprising:

a transistor comprising at least a source electrode, a drain electrode, and a gate electrode; and

a cantilever actuator comprising a piezoelectric material,

wherein the cantilever actuator is electrically isolated but mechanically connected to and integrated with the transistor through the gate electrode of the transistor,

wherein the cantilever actuator comprises at least two electrodes separate from the source electrode, the drain electrode, and the gate electrode, wherein the at least two electrodes comprise a first electrode and a second electrode, and

wherein the at least two electrodes allow for simultaneous actuating of the cantilever actuator separate from accessing of the transistor through the source electrode, the drain electrode, and the gate electrode.

2. The apparatus of claim 1, further comprising a sensing circuit coupled to at least the source electrode, the drain electrode, and the gate electrode of the transistor, wherein the sensing circuit is configured to detect pressure applied to the cantilever actuator by sensing a change in the threshold voltage of the transistor.

3. The apparatus of claim 2, wherein the piezoelectric material comprises a pyroelectric material, and wherein the sensing circuit is configured to detect a temperature of an environment around the cantilever actuator.

4. The apparatus of claim 1, further comprising a haptic feedback circuit coupled to the at least two electrodes of the cantilever actuator.

5. The apparatus of claim 4, wherein the haptic feedback circuit is configured to generate a direct current (DC) signal or an alternating current (AC) signal to deflect the cantilever actuator.

6. The apparatus of claim 5, wherein the haptic feedback circuit is configured to to generate a direct current (DC) signal and simulate a button raising from a surface.

7. The apparatus of claim 5, wherein the haptic feedback circuit is configured to generate an alternating current (AC) signal and a shake effect.

8. The apparatus of claim 1, wherein the cantilever actuator comprises PVDF and/or the cantilever actuator comprises a load attached at a distal end of the piezoelectric material from the transistor.

9. The apparatus of claim 1, wherein the transistor comprises at least one of a staggered bottom gate thin film transistor (TFT), a coplanar bottom-gate TFT, a staggered top-gate TFT, and a coplanar top-gate TFT.

10. The apparatus of claim 1, wherein the transistor and the cantilever are integrated in a display device, wherein the display device is part of an electronic device comprising at least one of a mobile device, a cellular phone, a laptop, a tablet, a media player, a global positioning system (GPS) device, and an e-book reader.

11. The apparatus of claim 1, wherein the transistor further comprises:

a first semiconductor channel region;

a second semiconductor channel region;

a dielectric layer over the first semiconductor channel region and the second semiconductor channel region; and

a piezoelectric layer over the first semiconductor channel region and the second semiconductor channel region,

wherein the gate electrode extends over the first semiconductor channel region and over the second semiconductor channel region.

12. The apparatus of claim 11, wherein the first semiconductor channel region comprises a p-type semiconductor, and where the second semiconductor channel region comprises a n-type semiconductor.

13. The apparatus of claim 12, further comprising:

a first source electrode coupled to the first semiconductor channel region;

a second source electrode coupled to the second semiconductor channel region; and

a drain electrode coupled to the first semiconductor channel region and coupled to the second semiconductor channel region.

14. The apparatus of claim 13, further comprising:

a first sensor circuit coupled to the first source electrode and the drain electrode, wherein the first sensor circuit is configured to measure a piezoelectric effect within the piezoelectric layer; and

a second sensor circuit coupled to the second source electrode and the drain electrode, wherein the second sensor circuit is configured to measure a pyroelectric effect within the piezoelectric layer.

15. An electronic device capable of providing haptic feedback to a user, the electronic device comprising:

an array of haptic feedback devices, wherein at least one haptic feedback device of the array of haptic feedback devices comprises;

a transistor comprising at least a source electrode, a drain electrode, and a gate electrode; and

a cantilever actuator comprising a piezoelectric material,

wherein the cantilever actuator is electrically isolated but mechanically connected to and integrated with the transistor through the gate electrode of the transistor,

wherein the cantilever actuator comprises at least two electrodes separate from the source electrode, the drain electrode, and the gate electrode, wherein the at least two electrodes comprise a first electrode and a second electrode, and

wherein the at least two electrodes allow for simultaneous actuating of the cantilever actuator separate from accessing of the transistor through the source electrode, the drain electrode, and the gate electrode.

16. The haptic feedback-enabled device of claim 15, further comprising a processor coupled to the array of haptic feedback devices, wherein the processor is configured to receive signals from the array of haptic feedback devices and is configured to determine a user input based on the received signals or the processor is configured to determine a haptic feedback sensation to provide to a user and configured to generate signals that when provided to the array of haptic feedback devices cause the user to receive the determined haptic feedback sensation.

17. The haptic feedback-enabled device of claim 15, further comprising a display device, wherein the array of haptic feedback devices is positioned above the display device.

18. A method, comprising:

detecting, through a transistor of a sensor, a change in induced charge of a piezoelectric film indicative of a user input to an electronic device, wherein the piezoelectric film is electrically isolated from the transistor but mechanically connected to the transistor;

determining, by a processor coupled to the transistor, whether a pressure was applied to the sensor based, at least in part, on the change in induced charge, wherein the change in induced charge is determined based, at least in part, on a threshold voltage of a transistor coupled to the piezoelectric film;

processing, by the processor, the user input based, at least in part, on the determined pressure at the sensor; and

performing, by the processor, an operation based, at least in part, on the received user input.

19. The method of claim 18, further comprising outputting a signal to the piezoelectric film of the sensor, wherein the signal induces movement an actuator of the sensor, wherein the signal comprises a direct current (DC) signal selected to move the actuator a determined distance or outputting a signal to the piezoelectric film of the sensor, wherein the signal comprises an alternating current (AC) signal selected to induce vibration in the actuator.

20. The method of claim 18, wherein the step of detecting the change in induced charge and the step of outputting the signal to the piezoelectric film are performed simultaneously.