High speed 3D multi touch sensitive device

• US 20120013569A1
• Filed: 07/15/2011
• Published: 01/19/2012
• Est. Priority Date: 10/13/2003
• Status: Active Grant

• Current Assignee: Anders Swedin
• Original Assignee: Anders Swedin
• Inventors: Swedin, Anders
• Granted Patent: US 8,531,431 B2
• Time in Patent Office: Days
• 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 (20) capable of determining at least one position of at least one conducting object (17, 51) with respect to (52) a display device (10) of said touch sensor (20), comprising:

said 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 (11) when the switching means is in a second state of operation,

wherein the measuring circuit (25, 27), when said switching means (22) is in said second state of operation, is adapted to perform at least one measurement of the capacitive load of said at least one display electrode (11), and

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

charging at least one capacitive load of said at least one display electrode (11) by a predefined signal (31), wherein said charging results in at least one charging curve (33);

determining the size of said at least one capacitive load of said at least one display electrode (11) by measuring at least one rise time of said at least one charging curve (33); and

calculating at least one position of said at least one conducting object (17, 51), with respect to (52) said display device (10), based on said determined size of the at least one capacitive load.

2. A touch sensor (20) according to claim 1, wherein said measuring circuit (25, 27) is further adapted to perform at least two measurements to determine at least two positions, at at least two time instants, of said at least one conducting object (17, 51), said measuring circuit (25, 27) is further adapted to determine from said at least two positions if said at least one conducting object has moved or not.

3. A touch sensor (20) according to claim 2, wherein said measuring circuit (25, 27) is further adapted to, based on said at least two measurements, determine the direction of which said conducting object (17, 51) has moved between said at least two measurements.

4. A touch sensor (20) according to claim 3, wherein said measuring circuit (25, 27) is further adapted to, based on said at least two measurements, determine the speed of which said conducting object (17, 51) is moving between said at least two measurements.

5. A touch sensor (20) according to any of the previous claims, wherein said measuring circuit (25, 27) is further adapted to perform at least three measurements to determine if said speed of said conducting object (17, 51) is increasing, decreasing or constant.

6. A method for determining at least one position of at least one conducting object (17, 51) with respect to (52) a display device (10) of a touch sensor (20), wherein said 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), wherein said at least one display electrode (11) is coupled to an interface (21) for receiving display data to the display device (10), the method 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);

performing at least one measuring of at least one capacitive load of said at least one display electrode (11) at an time instant, wherein the measuring comprises;

charging at least one capacitive load of said at least one display electrode (11) by a predefined signal (31), wherein said charging results in at least one charging curve (33);

determining the size of said at least one capacitive load of said at least one display electrode (11) by measuring at least one rise time of said at least one charging curve (33); and

calculating at least one position of said at least one conducting object (17, 51), with respect to (52) said display device (10), based on said 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 said at least one conducting object (17, 51), the method further comprising determining from said at least two positions if said at least one conducting object has moved or not.

8. The method according to claim 7, further comprising determining, based on said at least two positions, the direction of which said conducting object (17, 51) has moved between said at least two measurements.

9. The method according to any of claims 7-8, further comprising determining, based on said at least two positions, the speed of which said conducting object (17, 51) is moving.

10. The method according to claim 9, further comprising performing at least three measurements to determine at if said speed of said conducting object (17, 51) is increasing, decreasing or constant.