Touch sensitive display device

• US 20100253641A1
• Filed: 03/22/2010
• Published: 10/07/2010
• Est. Priority Date: 10/13/2003
• Status: Abandoned Application

• Current Assignee: Anders Swedin
• Original Assignee: Integritouch Development AB
• Inventors: Swedin, Anders
• Application Number:
  US12/659,772
• Publication Number:
  US 20100253641A1
• Time in Patent Office: Days
• US Class Current: 345/173
• CPC Class Codes: G02F 1/13338 Input devices, e.g. touch panels
• CPC Class Codes: G02F 1/1343 Electrodes reflective electrodes G02F1/133553
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G09G 3/04 for presentation of a single character by selection from a plurality of characters, or by composing the character by combination of individual elements, e.g. segments using a combination of such display devices for composing words, rows or the like, in a frame with fixed character positions

Abstract

A touch sensor is disclosed comprising a display device having a substrate on which substrate at least one display electrode is disposed for the display of a shape on the display device. An interface is coupled to the at least one display electrode for receiving display data to the display device. Moreover is a measuring circuit coupled to the at least one display electrode. Switching means are provided for connecting the interface to the at least one display electrode when the switching means is in a first state of operation and connecting the measuring circuit to the at least one display electrode when the switching means is in a second state of operation.

Claims

1. A touch sensor (20), comprising:

a display device 10 having a substrate (14, 15) on which substrate at least one display electrode (11) is disposed for the display of a shape on the display device (10);

an interface (21) coupled to the at least one display electrode (11) for receiving display data to the display device (10);

a measuring circuit (25, 27) coupled to the at least one display electrode (11);

switching means (22) for connecting the interface (21) to the at least one display electrode (11) when the switching means is in a first state of operation and connecting the measuring circuit (25, 27) to the at least one display electrode when the switching means is in a second state of operation.

2. A touch sensor (20) according to claim 1, wherein the measuring circuit (25, 27) is a capacitance measuring circuit.

3. A touch sensor (20) according to claim 1, wherein the measuring circuit (25, 27) is a resistance measuring circuit.

4. A touch sensor (20) according to any preceding claim, wherein the measuring circuit (25, 27) comprises a signal generator (25) coupled to the at least one display electrode (11) for providing a predetermined test signal to the display electrode, and a signal evaluating circuit (27) coupled to the at least one display electrode for receiving the test signal from the signal generator.

5. A touch sensor (20) according to claim 4, wherein the signal evaluation circuitry (27) is adapted to detect a deviation in the test signal when the switching means (22) is in the second state of operation.

6. A touch sensor (20) according to any of claims 4 or 5, wherein the signal generator (25) is adapted to apply the test signal to the segments (11) on a front substrate (14) of the display device (10).

7. A touch sensor (20) according to any of claims 4 or 4, wherein the signal generator (25) is adapted to apply the test signal to the segments (11) on a back substrate (14) of the display device (10).

8. A touch sensor (20) according to any preceding claim, wherein the segments (11) on the substrate (14, 15) which are not connected to the signal generator (25) are left in a high-ohmic state.

10. A method according to claim 7 comprising the steps of:

applying a predetermined test signal to the display electrode (11) and detecting a deviation in the test signal due to an electrical coupling towards an object (17) touching the display device 10 in the vicinity of the display electrode.

11. A method according to claim 9 or 10, wherein the electrical coupling is a capacitive coupling.

12. A method according to claim 9 or 10, wherein the electrical coupling is a galvanic coupling.

9. A method for detecting a touch on a display device (10), said display device having a substrate (14, 15) on which substrate at least one display electrode (11) is disposed for the display of a shape on the display device (10), wherein said display electrode (11) is coupled to an interface (21) for receiving display data to the display device, comprising the steps of:

disconnecting the at least one display electrode (11) from the interface (21);

connecting said display electrode (11) to a measuring circuit (25, 27); and

detecting a change in an electrical property of the display electrode (11) due to an electrical coupling towards an object (17) touching the display device (10) in the vicinity of the display electrode.