TOUCH PANEL AND METHOD OF DETECTING COORDINATE POSITION

• US 20130021089A1
• Filed: 01/24/2012
• Published: 01/24/2013
• Est. Priority Date: 01/27/2011
• Status: Active Grant

• Current Assignee: Fujitsu Component Limited (Fujitsu Limited)
• Original Assignee: Fujitsu Component Limited (Fujitsu Limited)
• Inventors: Sakurai, Satoshi, Shimizu, Nobuyoshi, Endo, Norio, Hirota, Shiro
• Granted Patent: US 9,019,216 B2
• Time in Patent Office: Days
• US Class Current: 327/517
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• 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 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

Disclosed is a touch panel including an upper conductive layer; a lower conductive layer facing the upper conductive layer with an interval between the upper conductive layer; a capacitive sensing unit that detects a coordinate position by a capacitive coupling under a condition where a predetermined electric potential is applied to the upper conductive layer; and a resistive sensing unit that detects a coordinate position based on an electric potential at a position where the upper conductive layer and the lower conductive layer contact under a condition where a potential gradient is generated on either one of the upper conductive layer and the lower conductive layer.

Claims

1. A touch panel comprising:

an upper conductive layer;

a lower conductive layer facing the upper conductive layer with an interval between the upper conductive layer;

a capacitive sensing unit that detects a coordinate position by a capacitive coupling under a condition where a predetermined electric potential is applied to the upper conductive layer; and

a resistive sensing unit that detects a coordinate position based on an electric potential at a position where the upper conductive layer and the lower conductive layer come into contact under a condition where a potential gradient is generated on either one of the upper conductive layer or the lower conductive layer.

2. The touch panel according to claim 1, wherein the resistive sensing unit includes

a first electric potential detecting unit that is connected to the upper conductive layer and that detects the potential of the upper conductive layer under a condition where a potential gradient is generated in a first direction on the lower conductive layer, and

a second electric potential detecting unit that is connected to the lower conductive layer and that detects the potential of the lower conductive layer under a condition where a potential gradient is generated in a second direction different from the first direction on the upper conductive layer.

3. The touch panel according to claim 1, wherein the resistive sensing unit includes an electric potential detecting unit that is connected to the upper conductive layer and that detects the potential of the upper conductive layer under a condition where a potential gradient is generated in a certain direction on the lower conductive layer.

4. The touch panel according to claim 3, wherein the electric potential detecting unit detects an electric potential of the upper conductive layer under a first condition where a potential gradient is generated in a first direction on the lower conductive layer and under a second condition where a potential gradient is generated in a second direction different from the first direction on the lower conductive layer.

5. The touch panel according to claim 1, further comprising a transparent substrate, the upper conductive layer being formed to be separated into plural areas including a first group of areas aligned in a first direction and a second group of areas aligned in a second direction perpendicular to the first direction, wherein the first group of areas and the second group of areas are formed on a surface of the transparent substrate facing the lower conductive layer.

6. The touch panel according to claim 1, further comprising a transparent substrate, the upper conductive layer being formed to be separated into plural areas including a first group of areas aligned in a first direction formed on one surface of the transparent substrate and a second group of areas aligned in a second direction perpendicular to the first direction formed on the other surface of the transparent substrate facing the lower conductive layer.

7. The touch panel according to claim 2, further comprising a transparent substrate, the upper conductive layer being formed to be separated into plural areas including a first group of areas aligned in the first direction formed on one surface of the transparent substrate and a second group of areas aligned in the second direction perpendicular to the first direction formed on the other surface of the transparent substrate facing the lower conductive layer.

8. The touch panel according to claim 1, wherein detection by the capacitive sensing unit and detection by the resistive sensing unit are performed at different timing.

9. The touch panel according to claim 1, wherein the capacitive sensing unit includes plural current detecting units provided to detect current values of the different positions of the upper conductive layer and the coordinate position is detected based on the current values detected by the plural current detecting units.

10. The touch panel according to claim 1, wherein the lower conductive layer is kept at a ground potential when detection by the capacitive sensing unit is performed.

11. A method of detecting a coordinate position by a touch panel including an upper conductive layer and a lower conductive layer facing the upper conductive layer with an interval between the upper conductive layer, comprising:

detecting, by a capacitive sensing mode, a coordinate position by a capacitive coupling under a condition where a predetermined electric potential is applied to the upper conductive layer; and

detecting, by a resistive sensing mode, a coordinate position based on an electric potential at a position where the upper conductive layer and the lower conductive layer contact under a condition where a potential gradient is generated on either one of the upper conductive layer and the lower conductive layer.

12. The method of detecting a coordinate position according to claim 11, wherein the step of detecting the coordinate position by the resistive sensing mode includes,

detecting the electric potential of the upper conductive layer under a condition where a potential gradient is generated in a first direction on the lower conductive layer, and

detecting the electric potential of the lower conductive layer under a condition where a potential gradient is generated in a second direction different from the first direction on the upper conductive layer.

13. The method of detecting a coordinate position according to claim 11, wherein the step of detecting the coordinate position by the resistive sensing mode includes detecting the electric potential of the upper conductive layer under a condition where a potential gradient is generated in a certain direction on the lower conductive layer.

14. The method of detecting a coordinate position according to claim 11, wherein the step of detecting the coordinate position by the resistive sensing mode includes detecting an electric potential of the upper conductive layer under a first condition where a potential gradient is generated in a first direction on the lower conductive layer and under a second condition where a potential gradient is generated in a second direction different from the first direction on the lower conductive layer.

15. The method of detecting a coordinate position according to claim 11, wherein the step of detecting the coordinate position by the resistive sensing mode and the step of detecting the coordinate position by the capacitive sensing mode are repeatedly performed.

16. The method of detecting a coordinate position according to claim 11, wherein when touching is not detected in the step of detecting the coordinate position by the resistive sensing mode, the process moves to the step of detecting the coordinate position by the capacitive sensing mode.

17. The method of detecting a coordinate position according to claim 11, wherein when touching is not detected in the step of detecting the coordinate position by the capacitive sensing mode, the process moves to the step of detecting the coordinate position by the resistive sensing mode.