Touch recognition apparatus and method in capacitive touch screen

• US 8,692,797 B2
• Filed: 12/07/2011
• Issued: 04/08/2014
• Est. Priority Date: 12/14/2010
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: Shin, Jong Woo
• Primary Examiner(s): Lefkowitz, Sumati
• Assistant Examiner(s): Wilson, Douglas M
• Application Number:
  US13/313,589
• Publication Number:
  US 20120146941A1
• Time in Patent Office: 853 Days
• Field of Search: 323/208, 323/316, 323/321, 324/322, 324/338, 324/403, 324/603, 324/647, 327/101, 327/517, 340/407.1, 340/407.2, 340/5.54, 340/5.83, 340/527, 340/539, 340/540, 345/1.3, 345/156, 345/157, 345/158, 345/161, 345/163, 345/166, 345/168, 345/169, 345/171, 345/173, 345/174, 345/175, 345/179, 345/204, 345/207, 345/211
• US Class Current: 345/174
• 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 3/044 by capacitive means
• 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 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact

Abstract

A touch recognition apparatus and method in a capacitive touch screen are provided. The touch recognition apparatus includes a touch panel and a controller. The touch panel includes a first sub panel and a second panel intersecting each other. The first sub panel includes a first electrode line and a second electrode line in X axis, and a plurality of resistors connected between the first electrode line and the second electrode line in X axis. The controller outputs scan signals to the first electrode line in X axis and the first electrode line in Y axis, receives scan sensing signals through the second electrode line in X axis and the second electrode line in Y axis, and measures delay times between the scan signals and the scan sensing signals to touched positions in X axis and Y axis, respectively.

Claims

1. A touch recognition apparatus in a capacitive touch screen, the apparatus comprising:

a touch panel including a first sub panel and a second sub panel intersecting each other, the first sub panel including a first electrode line and a second electrode line in an X axis, a plurality of resistors being connected between the first electrode line and the second electrode line in the X axis, sub electrode lines being connected to access nodes of the resistors, the second sub panel including a first electrode line and a second electrode line in a Y axis, a plurality of resistors being serially connected between the first electrode line and the second electrode line in the Y axis, and sub electrode lines being connected to access nodes of the resistors; and

a controller for outputting scan signals to the first electrode line in the X axis and the first electrode line in the Y axis, for receiving scan sensing signals through the second electrode line in the X axis and the second electrode line in the Y axis, and for measuring delay times between the scan signals and the scan sensing signals to determine touched positions in the X axis and the Y axis, respectively.

2. The apparatus of claim 1, wherein the controller comprises a first position determinator for determining a position in the X axis and a second position determinator for determining a position in the Y axis, and

wherein each of the first and second determinators comprises:

a delay measuring unit for measuring a delay time between generation of the scan signal and reception of the scan sensing signal; and

a sensor for analyzing the delay time output from the delay measuring unit to determine the position in the X axis or the Y axis.

3. The apparatus of claim 2, wherein the delay measuring unit comprises:

a converter for converting the scan sensing signal into digital data;

a comparator for comparing the digital data with a threshold value and for generating a comparison result signal when the digital data exceed the threshold value; and

a counter, activated when the scan signal is generated, for counting a generation time of the comparison result signal to measure a delay time of the scan sensing signal.

4. The apparatus of claim 3, wherein the controller further comprises a key and an item mapping table corresponding to a position of a touch panel, determines the positions in the X axis and the Y axis through the sensor, and processes a key or an item of a mapping table corresponding to the determined positions in the X axis and the Y axis.

5. The apparatus of claim 2, wherein the scan signal comprises a square wave, having an off voltage and an on voltage, output by the controller at a predefined scan period.

6. The apparatus of claim 2, wherein the delay measuring unit determines that the scan sensing signal is received when a voltage level of the scan sensing signal increases to the on voltage level of the scan signal.

7. A touch recognition method in a capacitive touch screen, the method comprising:

outputting a scan signal in a first electrode line in an X axis and a first electrode line in a Y axis in a touch panel of the capacitive touch screen including a first sub panel and a second sub panel intersecting each other, the first sub panel including the first electrode line and a second electrode line in the X axis, a plurality of resistors being connected between the first electrode line and the second electrode line in the X axis, sub electrode lines being connected to access nodes of the resistors, the second sub panel including the first electrode line and a second electrode line in the Y axis, a plurality of resistors being serially connected between the first electrode line and the second electrode line in the Y axis, and sub electrode lines being connected to access nodes of the resistors;

receiving respective scan sensing signals through the second electrode line in the X axis and the second electrode line in the Y axis;

measuring a delay time between the outputting of the scan signal and the receiving of the scan sensing signal; and

analyzing the delay time to determine touched positions in the X axis or the Y axis.

8. The method of claim 7, wherein the measuring of the delay time comprises:

converting the scan sensing signal into digital data;

comparing the digital data with a threshold value and generating a comparison result signal when the digital data exceed the threshold value; and

counting, beginning when the scan signal is generated, a generation time of the comparison result signal to measure the delay time of the scan sensing signal.

9. The method of claim 8, wherein the touch screen comprises a key and an item mapping table corresponding to a position of a touch panel, the method further comprising processing a key or an item of a mapping table corresponding to determined positions in the X axis and the Y axis.

10. The method of claim 8, wherein the outputting of the scan signal comprises outputting a square wave, having an off voltage and an on voltage, at a predefined scan period.

11. The method of claim 10, wherein the counting of the generation time comprises determining that the scan sensing signal is received when a voltage level of the scan sensing signal increases to the on voltage level of the scan signal.