CAPACITIVE TOUCH PANEL

• US 20120154323A1
• Filed: 09/23/2011
• Published: 06/21/2012
• Est. Priority Date: 12/15/2010
• Status: Abandoned Application

• Current Assignee: SMK Corporation
• Original Assignee: SMK Corporation
• Inventors: Nambu, Mototoshi
• Application Number:
  US13/243,100
• Publication Number:
  US 20120154323A1
• Time in Patent Office: Days
• 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 3/0445 using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer
• 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

Abstract

A capacitive touch panel that detects an input position accurately with a limited number of sensing electrodes is provided. First and second sensing electrodes adjacent to each other in a detecting direction are arranged such that among a plurality of branch patterns of the first sensing electrode a branch pattern closer to the second sensing electrode, and among a plurality of branch patterns of the second sensing electrode a branch pattern closer to the first sensing electrode are alternately arranged in the detecting direction. The widths in the detecting direction of the plurality of branch patterns of each sensing electrode are set such that the branch patterns on the opposite sides in the detecting direction have the smallest width, and the width of a branch pattern gradually becomes greater as the branch pattern gets closer to a branch pattern at the center.

Claims

1. A capacitive touch panel for detecting a change of a stray capacitance of each of a plurality of sensing electrodes spaced a predetermined distance in a detecting direction of an input position on an insulating substrate, and detecting a position of an input made by an input unit on the basis of a location of a sensing electrode on the insulating substrate that is changed in stray capacitance in response to the input unit approaching the sensing electrode, wherein:

each sensing electrode is divided into a plurality of branch patterns extending like comb teeth in a direction perpendicular to the detecting direction;

first and second sensing electrodes adjacent to each other in the detecting direction are arranged such that among a plurality of branch patterns of the first sensing electrode a branch pattern closer to the second sensing electrode, and among a plurality of branch patterns of the second sensing electrode a branch pattern closer to the first sensing electrode are alternately arranged in the detecting direction; and

widths in the detecting direction of the plurality of branch patterns of each sensing electrode are formed such that the branch patterns on the opposite sides in the detecting direction have the smallest width, and the width of a branch pattern gradually becomes greater as the branch pattern gets closer to a branch pattern at the center.

2. The capacitive touch panel according to claim 1, wherein:

the first and second sensing electrodes are divided at opposite sides of a direction perpendicular to the detecting direction into branch patterns such that the respective branch patterns of the first and second sensing electrodes interlock with each other; and

the second sensing electrode is pulled out through the branch pattern at the center of the second sensing electrode to the same direction to which the first sensing electrode is pulled out.

3. The capacitive touch panel according to claim 1, wherein the insulating substrate has a front surface on which a plurality of X sensing electrodes are placed that define an X direction as the detecting direction, and a rear surface on which a plurality of Y sensing electrodes are placed that define a Y direction perpendicular to the X direction as the detecting direction.

4. The capacitive touch panel according to claim 1, wherein a distance D1 between the respective branch patterns alternately arranged of the first and second sensing electrodes is equal to or less than (d+wb)/2, where wb is a smaller width in the detecting direction of a branch pattern of either the first or second sensing electrode adjacent to each other, and d is a width in the detecting direction of the input unit.

5. The capacitive touch panel according to claim 1, wherein a distance D2 between the respective branch patterns alternately arranged of the first and second sensing electrodes is equal to or less than (d−

wa)/2, where wa is a greater width in the detecting direction of a branch pattern of either the first or second sensing electrode adjacent to each other, and d is a width in the detecting direction of the input unit.