TOUCH SENSOR DEVICE AND ELECTRONIC DEVICE

• US 20150177980A1
• Filed: 12/22/2014
• Published: 06/25/2015
• Est. Priority Date: 12/24/2013
• Status: Active Grant

• Current Assignee: Tianma Microelectronics Company Limited
• Original Assignee: NLT Technologies, Ltd. (Tianma Microelectronics Company Limited)
• Inventors: YANASE, Jiro, NONAKA, Yoshihiro
• Granted Patent: US 9,904,464 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• 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 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

A touch sensor device includes: an impedance surface where plural sets of reference coordinates are set at plural locations; plural detection electrodes arranged on the impedance surface; a detection circuit configured to detect electric currents passing the detection electrodes; a storage section storing reference standardized values and reference normalized values; a position coordinate calculation section configured to obtain standardized values calculated by standardizing the electric currents detected in each detection period and to map the standardized values onto position coordinates; a first normalized value calculation section configured to map the position coordinates onto first normalized values; a second normalized value calculation section configured to calculate second normalized values by normalizing the electric currents in each detection period; and a touch gesture detection section configured to detect a motion of pointers on the basis of a time variation of the first normalized values and the second normalized values.

Claims

1. A touch sensor device comprising:

a transparent conductive layer forming an impedance surface, the impedance surface including an active area where a human body can touch or approach, a plurality of sets of reference coordinates being set at a plurality of locations in the active area;

a plurality of detection electrodes arranged on the impedance surface;

a detection circuit configured to detect electric currents passing the detection electrodes;

a storage section storing reference standardized values and reference normalized values, the reference standardized values corresponding to estimated coordinates of each set of the reference coordinates, the reference standardized values being calculated by obtaining electric currents detected by the detection circuit on each set of the reference coordinates being pointed with one pointer and by standardizing the detected electric currents for each set of the reference coordinates, the reference normalized values being calculated by normalizing the detected electric currents so as to make a total sum of the electric currents passing the impedance surface a constant value, for each set of the reference coordinates;

a position coordinate calculation section configured to obtain standardized values calculated by standardizing the electric currents detected by the detection circuit in each detection period and to map the standardized values onto position coordinates on a basis of a relation between the reference standardized values stored in advance in the storage section and the reference coordinates;

a first normalized value calculation section configured to map the position coordinates onto first normalized values on a basis of a relation between the reference coordinates and the reference normalized values;

a second normalized value calculation section configured to calculate second normalized values by normalizing the electric currents detected by the detection circuit in each detection period; and

a touch gesture detection section configured to detect a motion of a plurality of pointers on a basis of a time variation of the first normalized values and the second normalized values.

2. The touch sensor device of claim 1, wherein

each of a number of elements of the reference normalized values, a number of elements of the first normalized values, and a number of elements of the second normalized values is greater than a number of elements of the reference standardized values, and

each of the number of elements of the reference normalized values, the number of elements of the first normalized values, and the number of elements of the second normalized values is greater than a number of elements of the standardized values.

3. The touch sensor device of claim 2, wherein

each of the number of elements of the reference normalized values, the number of elements of the first normalized values, and the number of elements of the second normalized values is four.

4. The touch sensor device of claim 2, wherein

each of the number of elements of the reference standardized values and the number of elements of the standardized values is two.

5. The touch sensor device of claim 1, wherein

the impedance surface has a rectangular shape, and

the detection electrodes are arranged at four corners of the rectangular shape, in the middles of four sides of the rectangular shape, or at the four corners and in the middles of four sides of the rectangular shape.

6. The touch sensor device of claim 1, wherein

the position coordinate calculation section configured to,

on one pointer touching or approaching the impedance surface, calculate a pointing position of the one pointer as the position coordinates, and

on two pointers touching or approaching the impedance surface, calculate a position in the middle of the two pointers as the position coordinates.

7. The touch sensor device of claim 1, wherein

either the first normalized values or the position coordinates are calculated by using an interpolation function for carrying out interpolation using a polygon surrounded by points represented by the reference normalized values.

8. The touch sensor device of claim 1, wherein

the touch gesture detection section is configured to detect the motion of the plurality of pointers using an indicator value 1 obtained by

9. The touch sensor device of claim 1, wherein

the touch gesture detection section is configured to

calculate a distance between two pointers that touch or approach the impedance surface by using the first normalized values and the second normalized values, and

detect a pinch gesture operation in which the two pointers move away from each other or move closer to each other, by using a time variation of the distance between the two pointers.

10. The touch sensor device of claim 9, wherein

the touch gesture detection section is configured to calculate the distance between the two pointers by using an absolute value of a difference between the first normalized value and the second normalized value.

11. The touch sensor device of claim 9, wherein

the touch gesture detection section is configured to define the distance between the two pointers as a reference distance value, the distance being calculated immediately after determining a touch state of the pointers such that the pointers touch or approach the impedance surface as a touch-on state.

12. The touch sensor device of claim 11, wherein

the touch gesture detection section is configured to, on detecting a pinch-in operation that reduces the distance between the two pointers or a pinch-out operation that increases the distance between the two pointers, update the reference distance value by assigning the distance between two pointers to the reference distance value.

13. The touch sensor device of claim 9, wherein

the touch gesture detection section is configured to invalidate detection a pinch-in operation that reduces the distance between the two pointers or a pinch-out operation that increases the distance between the two pointers when a change of the position coordinates coming from a change of the distance between the two pointers is greater than a predetermined threshold value.

15. An electronic device including the touch sensor device of claim 1.

14. A touch sensor device comprising:

a transparent conductive layer forming an impedance surface where a human body can touch or approach;

a plurality of detection electrodes arranged on the impedance surface;

a detection circuit configured to detect electric currents passing the detection electrodes; and

a touch gesture detection section configured to detect a motion of a plurality of pointers by using the electric currents detected by the detection circuit, wherein sensitivity to one of a detected pinch-in operation and a detected pinch-out operation both changing a distance between two pointers, is higher at a second angle in comparison with the sensitivity at a first angle, where

each of the first angle and the second angle is an angle formed, under a condition that two pointers touch the impedance surface and a midpoint of the two pointers is defined as a center of the impedance surface, by a line connecting the two pointers and a line connecting opposing detection electrodes on the impedance surface in a pinch gesture operation that changes the distance between the two pointers, and

the first angle and the second angle satisfy;

“

first angle”

=(2×

m−

1)×

180/ET and

“

second angle”

=360/ET×

(m−

1),

where ET is a number of the detection electrodes and m is an integer from 1 to ET.

16. An electronic device including the touch sensor device of claim 14.