INDUCTIVE TOUCH SCREEN AND METHODS FOR USE THEREWITH

• US 20100265190A1
• Filed: 04/20/2009
• Published: 10/21/2010
• Est. Priority Date: 04/20/2009
• Status: Active Grant

• Current Assignee: Avago Technologies International Sales Pte Limited (Broadcom, Inc.)
• Original Assignee: Broadcom Corporation (Broadcom, Inc.)
• Inventors: Rofougaran, Ahmadreza (Reza)
• Granted Patent: US 8,810,523 B2
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G06F 3/046 by electromagnetic means

Abstract

A touch screen includes a display layer for displaying information. An inductor grid includes a plurality of inductive elements arranged on a single layer. At least one switch matrix selects an inductive element in response to the selection signal. A driver generates the selection signal, drives the selected inductive element to detect a touch object in proximity to the selected inductive element and generates touch screen data in response thereto.

Claims

1. A touch screen comprising:

a display layer for displaying information;

an inductor grid, coupled to display layer, that includes a plurality of inductive elements arranged on a single layer;

at least one switch matrix, coupled to the inductor grid, that selects a selected one of the plurality of inductive elements in response to at least one selection signal;

a driver, coupled to the at least one switch matrix and the inductor grid, that generates the at least one selection signal and that drives the selected one of the plurality of inductive elements to detect a touch object in proximity to the selected one of the plurality of inductive elements and that generates touch screen data in response thereto.

2. The touch screen of claim 1 wherein the plurality of inductive elements each include a single inductor and wherein the driver detects the touch object in proximity to the selected one of the plurality of inductive elements based on a measured self inductance of the single inductor.

3. The touch screen of claim 2 wherein the driver executes a calibration procedure to detect an initial self inductance, and wherein the driver generates touch screen data based on a comparison of the measured self inductance and the initial self inductance.

4. The touch screen of claim 1 wherein the plurality of inductive elements each include a inductor pair and wherein the driver detects the touch object in proximity to the selected one of the plurality of inductive elements based on a mutual inductance of the inductor pair.

5. The touch screen of claim 1 wherein the touch screen data includes a grid position associated with the selected one of the plurality of inductive elements.

6. The touch screen of claim 1 wherein the switch matrix includes a row matrix and a column matrix, the at least one selection signal includes a row selection signal and a column selection signals and the driver includes a row/column selector that generates the row selection signal and the column selection signal to sequentially scan the plurality of inductive elements.

7. The touch screen of claim 6 wherein the driver includes a controller, coupled to the row/column selector, that generates the touch screen data.

8. The touch screen of claim 1 wherein the driver includes a signal generator for generating an oscillation to drive the selected one of the plurality of inductive elements and a sensing circuit that generates a sensing signal in response to the oscillation.

9. The touch screen of claim 1 wherein the driver includes a signal generator for generating a pulse to drive the selected one of the plurality of inductive elements and a sensing circuit that generates a sensing signal in response to the pulse.

10. The touch screen of claim 1 wherein the touch object includes at least one of:

a finger; and

a stylus.

11. A method for use in a touch screen, the method comprising:

displaying information via a display layer;

generating at least one selection signal;

selecting, in response to the at least one selection signal, a selected one of a plurality of inductive elements arranged on a single layer;

driving the selected one of the plurality of inductive elements;

detecting a touch object in proximity to the selected one of the plurality of inductive elements; and

generating touch screen data in response to detecting the touch object in proximity to the selected one of the plurality of inductive elements.

12. The method of claim 11 wherein the plurality of inductive elements each include a single inductor;

and

wherein driving the selected one of the plurality of inductive elements includes detecting the touch object in proximity to the selected one of the plurality of inductive elements based on a measured self inductance of the single inductor.

13. The method of claim 12 wherein driving the selected one of the plurality of inductive elements includes executing a calibration procedure to detect an initial self inductance;

and

wherein generating the touch screen data includes generating the touch screen data based on a comparison of the measured self inductance and the initial self inductance.

14. The method of claim 11 wherein the plurality of inductive elements each include a inductor pair;

and

wherein driving the selected one of the plurality of inductive elements includes detecting the touch object in proximity to the selected one of the plurality of inductive elements based on a mutual inductance of the inductor pair.

15. The method of claim 11 wherein the touch screen data includes a grid position associated with the selected one of the plurality of inductive elements.

16. The method of claim 11 wherein the at least one selection signal includes a row selection signal and a column selection signals;

and

the generating the selection signal includes generating the row selection signal and the column selection signal to sequentially scan the plurality of inductive elements.

17. The method of claim 11 wherein driving the selected one of the plurality of inductive elements includes:

generating an oscillation to drive the selected one of the plurality of inductive elements; and

generating a sensing signal in response to the oscillation.

18. The method of claim 11 wherein driving the selected one of the plurality of inductive elements includes:

generating a pulse to drive the selected one of the plurality of inductive elements; and

generating a sensing signal in response to the pulse.

19. The method of claim 11 wherein the touch object includes at least one of:

a finger; and

a stylus.

20. The method of claim 11 wherein generating touch screen data in response to detecting the touch object in proximity to the selected one of the plurality of inductive elements includes detecting the touch object deflecting the display layer.