High speed 3D multi touch sensitive device

• US 8,531,431 B2
• Filed: 07/15/2011
• Issued: 09/10/2013
• Est. Priority Date: 10/13/2003
• Status: Active Grant

• Current Assignee: Integritouch Development AB
• Original Assignee: Integritouch Development AB
• Inventors: Swedin, Anders
• Primary Examiner(s): Bolotin, Dmitriy
• Application Number:
  US13/137,021
• Publication Number:
  US 20120013569A1
• Time in Patent Office: 788 Days
• Field of Search: 345173-178, 345/104, 345/156, 178 1801- 1811
• US Class Current: 345/174
• 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 2203/04101 2.5D-digitiser, i.e. digitiser detecting the X/Y position of the input means, finger or stylus, also when it does not touch, but is proximate to the digitiser's interaction surface and also measures the distance of the input means within a short range in the Z direction, possibly with a separate measurement setup
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/044 by capacitive means
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G09G 3/18 using liquid crystals

Abstract

Disclosed are a touch sensor and a method for determining a position, in three dimensions, of a conducting object with respect to a display device of the touch sensor. The determination of the position of the conducting object is done by performing at least one measurement of the capacitive load of at least one display electrode of the display wherein the measurement is performed by charging the capacitive load of the at least one display electrode by a predefined signal. The charging results in at least one charging curve, from which the capacitive load of the at least one display electrode may be determined by measuring the rise time of the charging curve of the charging, and calculating the position of the at least one conducting object, with respect to said display device based on the determined capacitive load.

Claims

1. A touch sensor capable of determining at least one position of at least one conducting object with respect to a display device of the touch sensor, comprising:

in the display device a first substrate on which at least a first display electrode is disposed and a second substrate on which at least a second display electrode is disposed, for the display of a shape on the display device;

an interface coupled to at least one of the first display electrode or the second display electrode for receiving display data to the display device;

a measuring circuit coupled to the at least one display electrode;

a switching circuit for;

connecting the interface to the at least one display electrode when the switching means is in a first state of operation;

disconnecting the interface from the at least one display electrode; and

connecting the measuring circuit to the at least one display electrode when the switching circuit is in a second state of operation,

wherein the switching circuit is adapted to preserve the voltage value between the first display electrode on the first substrate and the second display electrode on the second substrate when the switching circuit is in the second state of operation,

wherein the measuring circuit, when the switching circuit is in the second state of operation, is adapted to perform at least one measurement of the capacitive load of the at least one display electrode, and

wherein the measurement is performed by, at a time instant;

charging at least one capacitive load of the at least one display electrode by a predefined signal, wherein the charging results in at least one charging curve;

determining the size of the at least one capacitive load of the at least one display electrode by measuring at least one rise time of the at least one charging curve; and

calculating at least one position of the at least one conducting object, with respect to the display device, based on the determined size of the at least one capacitive load.

2. The touch sensor according to claim 1, wherein the measuring circuit is further adapted to perform at least two measurements to determine at least two positions, at at least two time instants, of the at least one conducting object, the measuring circuit being further adapted to determine from the at least two positions if the at least one conducting object has moved or not.

3. The touch sensor according to claim 2, wherein the measuring circuit is further adapted to, based on the at least two measurements, determine the direction of which the conducting object has moved between the at least two measurements.

4. The touch sensor according to claim 3, wherein the measuring circuit is further adapted to, based on the at least two measurements, determine the speed of which the conducting object is moving between the at least two measurements.

5. The touch sensor according to any of claims 1 through 4, wherein the measuring circuit is further adapted to perform at least three measurements to determine if the speed of the conducting object is increasing, decreasing, or constant.

6. A method for determining at least one position of at least one conducting object with respect to a display device of a touch sensor, wherein the display device has a first substrate on which at least a first display electrode is disposed and a second substrate on which at least a second display electrode is disposed, for the display of a shape on the display device, wherein at least one of the first display electrode or the second display electrode is coupled to an interface for receiving display data to the display device, the method comprising the steps of:

disconnecting the at least one display electrode from the interface;

connecting the at least one display electrode to a measuring circuit while preserving the voltage value between the first display electrode on the first substrate and the second display electrode on the second substrate;

performing at least one measuring of at least one capacitive load of the at least one display electrode at an time instant, wherein the measuring comprises;

charging at least one capacitive load of the at least one display electrode by a predefined signal, wherein the charging results in at least one charging curve;

determining the size of the at least one capacitive load of the at least one display electrode by measuring at least one rise time of the at least one charging curve; and

calculating at least one position of the at least one conducting object, with respect to the display device, based on the determined size of the at least one capacitive load.

7. The method according to claim 6, further comprising performing at least two measurements to determine at least two positions, at at least two time instants, of the at least one conducting object, the method further comprising determining from the at least two positions if the at least one conducting object has moved or not.

8. The method according to claim 7, further comprising determining, based on the at least two positions, the direction of which the conducting object has moved between the at least two measurements.

9. The method according to any of claims 7-8, further comprising determining, based on the at least two positions, the speed of which the conducting object is moving.

10. The method according to claim 9, further comprising performing at least three measurements to determine if the speed of the conducting object is increasing, decreasing, or constant.