Method and device for position detection

• US 8,970,551 B2
• Filed: 09/18/2013
• Issued: 03/03/2015
• Est. Priority Date: 10/09/2009
• Status: Active Grant

• Current Assignee: eGalax_eMPIA Technology Inc.
• Original Assignee: eGalax_eMPIA Technology Inc.
• Inventors: Chang, Chin-Fu, Lee, Cheng-Han, Tang, Chi-Hao, Ho, Shun-Lung
• Primary Examiner(s): OSORIO, RICARDO
• Application Number:
  US14/030,418
• Publication Number:
  US 20140015798A1
• Time in Patent Office: 531 Days
• Field of Search: 345156-174, 178 1801- 1806, 324/658, 463/16, 463/20, 463/25
• US Class Current: 345/174
• CPC Class Codes: G01R 27/2605 Measuring capacitance capacitive sensors G01D5/24
• CPC Class Codes: G06F 2203/04103 Manufacturing, i.e. details related to manufacturing processes specially suited for touch sensitive devices
• CPC Class Codes: G06F 2203/04104 Multi-touch detection in digitiser, i.e. details about the simultaneous detection of a plurality of touching locations, e.g. multiple fingers or pen and finger
• CPC Class Codes: G06F 2203/04106 Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection
• CPC Class Codes: G06F 2203/04111 Cross over in capacitive digitiser, i.e. details of structures for connecting electrodes of the sensing pattern where the connections cross each other, e.g. bridge structures comprising an insulating layer, or vias through substrate
• CPC Class Codes: G06F 3/03545 Pens or stylus
• CPC Class Codes: G06F 3/04182 Filtering of noise external to the device and not generated by digitiser components
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/047 using sets of wires, e.g. crossed wires

Abstract

A method and device for position detection are disclosed. A self-capacitance detection can be performed by a sensing device. According to the result of the self-capacitance detection, a first mutual-capacitance detection can be performed for determining one or more first 1-D positions. According to the result of the first mutual-capacitance detection, a second mutual-capacitance detection can be performed for determining one or more second 1-D positions corresponding to each first 1-D position. One or more 2-D positions can be provided according to the one or more second 1-D positions corresponding to each first 1-D position. Besides, during the self-capacitance detection, the first mutual-capacitance detection, and the second mutual-capacitance detection, a touch related sensing information corresponding to a touch that covers a wide area can be neglected for palm rejection.

Claims

1. A method for position detection that neglects wide-area touches, comprising:

providing a sensing device including a plurality of sensors including a plurality of first sensors and a plurality of second sensors, these first and second sensors intersecting each other at a plurality of intersecting points;

obtaining a first 1-D sensing information from signals of the first sensors by self-capacitance detection;

obtaining a second 1-D sensing information from signals of the second sensors by self-capacitance detection;

determining a detected touch related sensing information based on the range of each touch related sensing information on the first 1-D sensing information and the second 1-D sensing information, wherein each touch related sensing information corresponds to a touch or approach by at least one external object;

analyzing at least one 1-D position based on each detected touch related sensing information; and

analyzing at least one 2-D position by performing mutual-capacitance detection on each 1-D position.

2. The method of claim 1, wherein the self-capacitance detection includes:

providing a driving signal to these first sensors, and detecting variations in capactively coupled signals between these first sensor and the at least one external object to obtain the first 1-D sensing information; and

providing a driving signal to these second sensors, and detecting variations in capactively coupled signals between these second sensor and the at least one external object to obtain the second 1-D sensing information.

3. The method of claim 1, wherein the mutual-capacitance detection includes:

providing a driving signal to one of these first sensors as a first single source, and detecting variations in capactively coupled signals between the first signal source, these first 1-D sensors and the at least one external object using these second sensors.

4. The method of claim 3, wherein the mutual-capacitance detection further includes:

selecting a sensor provided with the driving signal from one of these sensors based on the at least one 1-D position;

generating a third 1-D sensing information based on signals of these first sensors or the second sensors when each sensor selected based on the 1-D position is provided with the driving signal;

analyzing at least one first 1-D position corresponding to each 1-D position based on the third 1-D sensing information; and

providing at least one 2-D position based on the at least one first 1-D position corresponding to each 1-D position.

5. The method of claim 4, wherein when the 1-D position is analyzed from the touch related sensing information of the first 1-D sensing information, the sensor provided with the driving signal is the first sensor closest to the 1-D position, and when the 1-D position is analyzed from the touch related sensing information of the second 1-D sensing information, the sensor provided with the driving signal is the second sensor closest to the 1-D position.

6. The method of claim 3, wherein when the 1-D position or the first 1-D position is analyzed from the touch related sensing information of the first 1-D sensing information, the sensor provided with the driving signal is the first sensor closest to the 1-D position, and when the 1-D position or the first 1-D position is analyzed from the touch related sensing information of the second 1-D sensing information, the sensor provided with the driving signal is the second sensor closest to the 1-D position.

7. The method of claim 1, wherein the range of the detected touch related sensing information is smaller than a threshold.

8. The method of claim 1, wherein the first 1-D sensing information and the second 1-D sensing information including a plurality of differences, wherein each difference is generated based on a pair of sensors among these sensors.

9. A device for position detection that neglects wide-area touches, comprising:

a sensing device including a plurality of sensors including a plurality of first sensors and a plurality of second sensors, these first and second sensors intersecting each other at a plurality of intersecting points; and

a controller for performing at least the following operations;

obtaining a first 1-D sensing information from signals of the first sensors by self-capacitance detection;

obtaining a second 1-D sensing information from signals of the second sensors by self-capacitance detection;

determining a detected touch related sensing information based on the range of each touch related sensing information on the first 1-D sensing information and the second 1-D sensing information, wherein each touch related sensing information corresponds to a touch or approach by at least one external object;

analyzing at least one 1-D position based on each detected touch related sensing information; and

analyzing at least one 2-D position by performing mutual-capacitance detection on each 1-D position.

10. The device of claim 9, wherein the self-capacitance detection includes:

providing a driving signal to these first sensors, and detecting variations in capactively coupled signals between these first sensor and the at least one external object to obtain the first 1-D sensing information; and

providing a driving signal to these second sensors, and detecting variations in capactively coupled signals between these second sensor and the at least one external object to obtain the second 1-D sensing information.

11. The device of claim 9, wherein the mutual-capacitance detection includes:

providing a driving signal to one of these first sensors as a first single source, and detecting variations in capactively coupled signals between the first signal source, these first 1-D sensors and the at least one external object using these second sensors.

12. The device of claim 11, wherein the mutual-capacitance detection further includes:

selecting a sensor provided with the driving signal from one of these sensors based on the at least one 1-D position;

generating a third 1-D sensing information based on signals of these first sensors or the second sensors when each sensor selected based on the 1-D position is provided with the driving signal;

analyzing at least one first 1-D position corresponding to each 1-D position based on the third 1-D sensing information; and

providing at least one 2-D position based on the at least one first 1-D position corresponding to each 1-D position.

13. The device of claim 12, wherein when the 1-D position is analyzed from the touch related sensing information of the first 1-D sensing information, the sensor provided with the driving signal is the first sensor closest to the 1-D position, and when the 1-D position is analyzed from the touch related sensing information of the second 1-D sensing information, the sensor provided with the driving signal is the second sensor closest to the 1-D position.

14. The device of claim 11, wherein when the 1-D position or the first 1-D position is analyzed from the touch related sensing information of the first 1-D sensing information, the sensor provided with the driving signal is the first sensor closest to the 1-D position, and when the 1-D position or the first 1-D position is analyzed from the touch related sensing information of the second 1-D sensing information, the sensor provided with the driving signal is the second sensor closest to the 1-D position.

15. The device of claim 9, wherein the range of the detected touch related sensing information is smaller than a threshold.

16. The device of claim 9, wherein the first 1-D sensing information and the second 1-D sensing information including a plurality of differences, wherein each difference is generated based on a pair of sensors among these sensors.