INTERLEAVED PIEZOELECTRIC TACTILE INTERFACE

• US 20130257759A1
• Filed: 12/14/2012
• Published: 10/03/2013
• Est. Priority Date: 03/29/2012
• Status: Active Grant

• Current Assignee: Intermec Technologies Corporation (Honeywell International Inc.)
• Original Assignee: Intermec Technologies Corporation (Honeywell International Inc.)
• Inventors: DAGHIGH, Hamoon Ghasemzadeh
• Granted Patent: US 9,383,848 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/04144 using an array of force sensing means position sensing using the local deformation of sensor cells G06F3/0447

Abstract

A piezoelectric tactile input device and method in a computing environment. An embodiment disclosed herein includes a touch screen having several piezoelectric regions within a piezoelectric material layer that may generate a voltage when deformed in a localized area. The piezoelectric layer may be disposed between sensor layers of rows and columns of sensor traces for detecting the voltage generated at any particular piezoelectric region. The detected voltage signals may then be used to extrapolate the position of the localized area in which the piezoelectric layer was deformed (e.g., from a finger touch or a stylus). Further, because the piezoelectric layer generates a greater voltage in the presence of a greater pressure, the device may further decipher a relative level of force for the tactile input on the touch screen and detect multiple touch locations.

Claims

1. An interface, comprising:

a first signal layer having a plurality of rows of sensing regions aligned in a first direction;

a second signal layer having a plurality of columns of sensing regions aligned in a second direction;

a piezoelectric region between over each intersection of a row and a column; and

a sensing circuit coupled the first and second signal layers configured to determine a tactile input from signals generated by at least one of the piezoelectric regions.

2. The interface of claim 1, wherein the first and second signal layers comprise indium-tin oxide layers.

3. The interface of claim 1, wherein the first and second signal layers comprise a diamond-shaped interleaving pattern.

4. The interface of claim 1, further comprising a first protective layer adjacent to a first surface of the piezoelectric layer.

5. The interface of claim 1, wherein the sensing circuit further comprises an analog-to-digital converter.

6. The interface of claim 1, wherein each piezoelectric region further comprises a transparent polyvinylidene fluoride film having a thickness of approximately nine micrometers.

7. The interface of claim 1, wherein each piezoelectric region is disposed in a plane between the first signal layer and the second signal layer and each piezoelectric region further comprises a direction of polarization that is orthogonal to the plane.

8. The interface of claim 1, wherein each piezoelectric region comprises a circular shape having an area that is at least as large as an area of intersection between one row of the first signal layer and one column of the second signal layer.

9. A computing device, comprising

a processor;

a display coupled to the processor and configured to display graphics under the control of the processor; and

a touch screen overlaying the display and coupled to the processor;

the touch screen including;

a first signal layer having a plurality of rows of sensing regions aligned in a first direction;

a second signal layer having a plurality of columns of sensing regions aligned in a second direction;

a piezoelectric region between over each intersection of a row and a column; and

a sensing circuit coupled the first and second signal layers configured to determine a tactile input from signals generated by at least one of the piezoelectric regions.

10. The device of claim 9, wherein the touch screen further comprises a first polyethylene terephthalate layer adjacent to a first surface of the piezoelectric layer;

and

a protective layer adjacent to the first polyethylene terephthalate layer; and

a glass backer adjacent to a second surface of the piezoelectric layer.

11. The device of claim 9, wherein the processor is configured to determine multiple locations of tactile input.

12. The device of claim 9, wherein the processor is configured to determine a shape of the tactile input.

13. The device of claim 9, further comprising

a memory coupled to the processor and configured to store data about the tactile input over time;

and

a communication module coupled to the processor and configured to communicate data stored in the memory to a remote computing device.

14. The device of claim 9, further comprising:

a voltage recovery circuit coupled to the piezoelectric layer of the touch screen configured to receive a voltage generated from use of the touch screen; and

a battery coupled to the voltage recovery circuit and configured to be charged by the voltage generated from use of the touch screen.

15. The device of claim 9 further comprising a stylus input device for generating tactile input.

16. A method of detecting tactile input, the method comprising:

deforming at least one piezoelectric region amongst a plurality of piezoelectric regions;

detecting a respective voltage at the deformed region; and

determining a location of the deformation in response to the voltage.

17. The method of claim 16, wherein the deformation is created by a finger.

18. The method of claim 16, further comprising determining a relative level of pressure causing the deformation in the piezoelectric layer from the voltage detected.

19. The method of claim 16, wherein the detecting further comprises:

detecting the voltage generated at a first sensor that is amongst a plurality of first aligned sensors;

detecting the voltage generated at a second sensor that is amongst a plurality of second aligned sensors, the alignment of the second sensors substantially perpendicular to the first sensors;

wherein the determining of the location further comprises extrapolating the location based upon the detection at the first sensor and the second sensor.

20. The method of claim 16, further comprising harnessing the voltage generated by the deformation of the piezoelectric region to charge a battery.