Two-Dimensional Position Sensor

• US 20100258360A1
• Filed: 04/14/2009
• Published: 10/14/2010
• Est. Priority Date: 04/14/2009
• Status: Active Grant

• Current Assignee: Neodrón Limited (Atlantic IP Services Limited)
• Original Assignee: Atmel Corporation (Microchip Technology Incorporated)
• Inventors: Yilmaz, Esat
• Granted Patent: US 9,495,042 B2
• Time in Patent Office: Days
• US Class Current: 178/18.60
• CPC Class Codes: G06F 3/04166 Details of scanning methods, e.g. sampling time, grouping of sub areas or time sharing with display driving Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally G06F3/04184
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes

Abstract

A two dimensional position sensor having a touch-sensitive panel defined by a single-layer electrode pattern arranged on one side of a substrate. The electrode pattern is made up of ‘n’ electrode units extending row-wise over the panel. Each electrode unit is made up of a single drive electrode extending across the touch-sensitive area of the panel and a plurality of ‘m’ sense electrodes, which collectively laterally extend across the touch-sensitive area and individually each occupy only a portion of the lateral extent. The sense electrodes are longitudinally offset from their associated drive electrode so that one edge of each sense electrode lies adjacent to one edge of the drive electrode, these coupling edges being separated by a gap dimensioned so that in use each pair of drive and sense electrodes have efficient capacitively coupling across the gap. This electrode pattern allows the longitudinal extent of each electrode unit to be made relatively small, which in turn is better for sensing multiple simultaneous touches, since this benefits from having more electrode units in any given panel.

Claims

1. A two dimensional position sensor having a touch-sensitive area defined by a single-layer electrode pattern arranged on one side of a substrate, the electrode pattern having a lateral extent in a first direction and a longitudinal extent in a second direction transverse thereto and comprising a plurality of ‘

n’

electrode units, where n is at least 3, extending row-wise over the touch-sensitive area longitudinally offset from one another, wherein the electrode units each comprise a drive electrode laterally extending across the touch-sensitive area and a plurality of ‘

m’

sense electrodes, wherein m is at least 3, which collectively laterally extend across the touch-sensitive area and individually each occupy a portion of the lateral extent, the sense electrodes of each unit being longitudinally offset from the drive electrode so that one edge of each sense electrode lies adjacent to one edge of the drive electrode, these coupling edges being separated by a gap dimensioned so that in use each pair of drive and sense electrodes capacitively couple across the gap.

2. The sensor of claim 1, wherein the sense electrodes of each unit have different lateral extents.

3. The sensor of claim 2, wherein the different lateral extents alternate between first and second values for laterally adjacent sense electrodes.

4. The sensor of claim 1, further comprising laterally extending ground electrodes arranged between adjacent electrode units to screen them from each other and thereby suppress capacitive coupling between adjacent electrode units.

5. The sensor of claim 1, further comprising tracks extending from the periphery of the touch sensitive area to connect to respective ones of the sense electrodes, wherein the tracks extend adjacent to a further edge of the sense electrodes opposed to the coupling edge.

6. The sensor of claim 5, wherein the tracks have extension portions that extend in the first direction arranged between the sense electrodes of the electrode unit and a drive electrode of an adjacent electrode unit.

7. The sensor of claim 5, wherein some of the tracks from the sense electrodes connect to one lateral side of the touch-sensitive area and the other tracks connect to the other lateral side.

8. The sensor of claim 1, wherein each electrode unit has a longitudinal extent of no more than 7 mm.

9. The sensor of claim 1, wherein the drive and sense electrodes each have a longitudinal extent of no more than 1 mm.

10. The sensor of claim 1, further comprising:

(a) a capacitance measurement circuit connected to the electrodes and operable repeatedly to acquire sets of capacitance signal values from the touch-sensitive area, each set being made up of a capacitance signal value from each pair of drive and sense electrodes, each pair constituting a sensing element; and

(b) a processor connected to receive the sets of capacitance signal values and operable to process each set to compute and output coordinates of single or multiple touch locations on the touch-sensitive area, the processing of each set being performed by;

(i) identifying the sensing element having the largest capacitance signal value;

(ii) defining a region of the touch-sensitive area including said sensing element having the largest capacitance signal value and selected ones of its neighbors;

(iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch-sensitive area; and

(iv) outputting data indicating the coordinates of the touch location in each region identified.

11. A two dimensional position sensor having a touch-sensitive area defined by a single-layer electrode pattern arranged on one side of a substrate, the electrode pattern having a lateral extent in a first direction and a longitudinal extent in a second direction transverse thereto and comprising a plurality of ‘

n’

electrode units, where n is at least 3, extending column-wise over the touch-sensitive area laterally offset from one another, wherein the electrode units each comprise a sense electrode longitudinally extending down the touch-sensitive area and a plurality of ‘

m’

drive electrodes, wherein m is at least 3, which collectively longitudinally extend down the touch-sensitive area and individually each occupy a portion of the longitudinal extent, the drive electrodes of each unit being laterally offset from the sense electrode so that one edge of each drive electrode lies adjacent to one edge of the sense electrode, these coupling edges being separated by a gap dimensioned so that in use each pair of drive and sense electrodes capacitively couple across the gap.

12. The sensor of claim 11, further comprising longitudinally extending ground electrodes arranged between adjacent electrode units to screen them from each other and thereby suppress capacitive coupling between adjacent electrode units.

13. The sensor of claim 11, further comprising tracks extending from the periphery of the touch sensitive area to connect to respective ones of the drive electrodes, wherein the tracks extend adjacent to a further edge of the drive electrodes opposed to the coupling edge.

14. The sensor of claim 13, wherein the tracks have extension portions that extend in the second direction arranged between the sense electrodes of the electrode unit and a drive electrode of an adjacent electrode unit.

15. The sensor of claim 13, wherein some of the tracks from the drive electrodes connect to one longitudinal side of the touch-sensitive area and the other tracks connect to the other longitudinal side.

16. The sensor of claim 11, wherein each electrode unit has a lateral extent of no more than 7 mm.

17. The sensor of claim 11, wherein the drive and sense electrodes each have a lateral extent of no more than 1 mm.

18. The sensor of claim 11, further comprising:

(a) a capacitance measurement circuit connected to the electrodes and operable repeatedly to acquire sets of capacitance signal values from the touch-sensitive area, each set being made up of a capacitance signal value from each pair of drive and sense electrodes, each pair constituting a sensing element; and

(b) a processor connected to receive the sets of capacitance signal values and operable to process each set to compute and output coordinates of single or multiple touch locations on the touch-sensitive area, the processing of each set being performed by;

(i) identifying the sensing element having the largest capacitance signal value;

(ii) defining a region of the touch-sensitive area including said sensing element having the largest capacitance signal value and selected ones of its neighbors;

(iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch-sensitive area; and

(iv) outputting data indicating the coordinates of the touch location in each region identified.

19. A method of processing signals from a 2D touch-sensitive capacitive position sensor having a touch-sensitive area defined by a single-layer electrode pattern arranged on one side of a substrate, the electrode pattern having a lateral extent in a first direction and a longitudinal extent in a second direction transverse thereto and comprising a plurality of ‘

n’

electrode units, where n is at least 3, extending row-wise over the touch-sensitive area longitudinally offset from one another, wherein the electrode units each comprise a drive electrode laterally extending across the touch-sensitive area and a plurality of ‘

m’

sense electrodes, wherein m is at least 3, which collectively laterally extend across the touch-sensitive area and individually each occupy a portion of the lateral extent, the sense electrodes of each unit being longitudinally offset from the drive electrode so that one edge of each sense electrode lies adjacent to one edge of the drive electrode, these coupling edges being separated by a gap dimensioned so that in use each pair of drive and sense electrodes capacitively couple across the gap, wherein each pair of drive and sense electrodes constitutes a sensing element, the sensor further comprising a capacitance measurement circuit connected to the sensing elements and operable repeatedly to acquire sets of capacitance signal values, each set being made up of a capacitance signal value from each of the sensing elements; and

a processor connected to receive the sets of capacitance signal values and operable to process each set to compute and output coordinates of single or multiple touch locations on the touch-sensitive area, the method of processing each set comprising;

(i) identifying the sensing element having the largest capacitance signal value;

(ii) defining a region of the touch panel including said sensing element having the largest capacitance signal value and selected ones of its neighbors;

(iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch panel; and

(iv) outputting data indicating the coordinates of the touch location in each region identified.

20. A method of processing signals from a 2D touch-sensitive capacitive position sensor having a touch-sensitive area defined by a single-layer electrode pattern arranged on one side of a substrate, the electrode pattern having a lateral extent in a first direction and a longitudinal extent in a second direction transverse thereto and comprising a plurality of ‘

n’

electrode units, where n is at least 3, extending column-wise over the touch-sensitive area laterally offset from one another, wherein the electrode units each comprise a sense electrode longitudinally extending down the touch-sensitive area and a plurality of ‘

m’

drive electrodes, wherein m is at least 3, which collectively longitudinally extend down the touch-sensitive area and individually each occupy a portion of the longitudinal extent, the drive electrodes of each unit being laterally offset from the sense electrode so that one edge of each drive electrode lies adjacent to one edge of the sense electrode, these coupling edges being separated by a gap dimensioned so that in use each pair of drive and sense electrodes capacitively couple across the gap, wherein each pair of drive and sense electrodes constitutes a sensing element, the sensor further comprising a capacitance measurement circuit connected to the sensing elements and operable repeatedly to acquire sets of capacitance signal values, each set being made up of a capacitance signal value from each of the sensing elements; and

a processor connected to receive the sets of capacitance signal values and operable to process each set to compute and output coordinates of single or multiple touch locations on the touch-sensitive area, the method of processing each set comprising;

(i) identifying the sensing element having the largest capacitance signal value;

(ii) defining a region of the touch panel including said sensing element having the largest capacitance signal value and selected ones of its neighbors;

(iii) identifying and defining one or more further sensing elements and regions respectively, wherein each iteration excludes capacitance signal values from consideration if they lie in previously defined regions of the touch panel; and

(iv) outputting data indicating the coordinates of the touch location in each region identified.