Capacitive touch device capable of distinguishing between conductor and nonconductor

• US 8,842,094 B2
• Filed: 11/02/2011
• Issued: 09/23/2014
• Est. Priority Date: 11/03/2010
• Status: Expired due to Fees

• Current Assignee: Elan Microelectronics Corporation
• Original Assignee: Elan Microelectronics Corporation
• Inventors: Hsu, Hsin-Fu, Yang, Wei-Wen
• Primary Examiner(s): Kumar, Srilakshmi K
• Assistant Examiner(s): LANDIS, LISA S
• Application Number:
  US13/287,661
• Publication Number:
  US 20120103779A1
• Time in Patent Office: 1,056 Days
• Field of Search: None
• US Class Current: 345/174
• CPC Class Codes: G06F 3/0416 Control or interface arrangements specially adapted for digitisers
• CPC Class Codes: G06F 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/0447 Position sensing using the local deformation of sensor cells

Abstract

A capacitive touch device capable of distinguishing conductor and nonconductor includes a flexible sensor layer receiving a first driving signal, an elastic insulation layer below the flexible sensor layer, and an electrically conductive layer below the elastic insulation layer and receiving a second driving signal synchronous but out of phase to the first driving signal. The flexible sensor layer generates a capacitance variation responsive to an object touching thereon, for identifying the object as a conductor or a nonconductor.

Claims

1. A capacitive touch device capable of distinguishing between conductor and nonconductor, the capacitor touch device comprising:

a flexible sensor layer receiving a first periodic signal with a first phase;

an elastic insulation layer below the flexible sensor layer; and

an electrically conductive layer below the elastic insulation layer and receiving a second periodic signal with a second with a second phase, wherein the first phase is opposite to the second phase;

wherein the flexible sensor layer generates a capacitance variation responsive to an object touching thereon;

when the capacitance variation is positive, identifying the object as a conductor; and

when the capacitance variation is negative, identifying the object as a conductor.

2. The capacitive touch device as claimed in claim 1 further comprising a frame, wherein

the frame is mounted between the flexible sensor layer and the electrically conductive layer;

a sealed space is formed within the flexible sensor layer, the frame and the electrically conductive layer; and

the elastic insulation layer is mounted in the sealed space.

3. The capacitive touch device as claimed in claim 2, wherein the elastic insulation layer is a solid-state elastomer.

4. The capacitive touch device as claimed in claim 2, wherein the elastic insulation layer is a fluid.

5. The capacitive touch device as claimed in claim 4, wherein the fluid is air.

6. The capacitive touch device as claimed in claim 1, wherein the elastic insulation layer is a solid-state elastomer.

7. The capacitive touch device as claimed in claim 1, wherein the flexible sensor layer includes sensor traces covered by a protective film.

8. The capacitive touch device as claimed in claim 1, wherein the electrically conductive layer is a metal layer of a printed circuit board.

10. The capacitive touch device as claimed in claim 1, wherein a phase difference between the first phase and the second phase is 180 degrees.

11. The capacitive touch device as claimed in claim 1, wherein each of wave peaks of the first periodic signal corresponds to each of wave troughs of the second periodic signal.

9. A method for a capacitive touch device to distinguish between conductor and nonconductor, the capacitive touch device including a flexible sensor layer, an electrically conductive layer, and an elastic insulation layer sandwiched between the flexible sensor layer and the electrically conductive layer, the method comprising the steps of:

synchronously providing a first periodic signal with a first phase to the flexible sensor layer and providing a second periodic signal with a second phase to the electrically conductive layer, wherein the first phase is opposite to the second phase;

generating a capacitance variation between the flexible sensor layer and the electrically conductive layer by the flexible sensor layer responsive to an object touching the flexible sensor layer; and

identifying whether the object is a conductor or a nonconductor according to the capacitance variation;

when the capacitance variation is positive, identifying the object is a conductor; and

when the capacitance variation is negative, identifying the object is a nonconductor.

12. The capacitive touch device as claimed in claim 9, wherein a phase difference between the first phase and the second phase is 180 degrees.

13. The capacitive touch device as claimed in claim 9, wherein each of wave peaks of the first periodic signal corresponds to each of wave troughs of the second periodic signal.