Touch panel apparatus and method for detecting distance between touch input points on touch panel

• US 8,803,842 B2
• Filed: 11/26/2010
• Issued: 08/12/2014
• Est. Priority Date: 11/26/2009
• Status: Active Grant

• Current Assignee: Asahi Kasei Microdevices Corporation (Asahi Kasei Corporation)
• Original Assignee: Asahi Kasei Microdevices Corporation (Asahi Kasei Corporation)
• Inventors: Wakasugi, Junichi, Li, Kaichin
• Primary Examiner(s): Mengistu, Amare
• Assistant Examiner(s): PATEL, PREMAL R
• Application Number:
  US13/511,027
• Publication Number:
  US 20120262417A1
• Time in Patent Office: 1,355 Days
• Field of Search: 345/173, 345/174, 178/18.01
• US Class Current: 345/174
• 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 2203/04808 Several contacts: gestures triggering a specific function, e.g. scrolling, zooming, right-click, when the user establishes several contacts with the surface simultaneously; e.g. using several fingers or a combination of fingers and pen
• CPC Class Codes: G06F 3/045 using resistive elements, e.g. a single continuous surface or two parallel surfaces put in contact
• CPC Class Codes: G06F 3/04883 for inputting data by handwriting, e.g. gesture or text

Abstract

There are provided a touch panel apparatus and a method for detecting a distance between touch input points of a touch panel, with which it is possible to detect the distance between two points with accuracy, when two points are touched on the touch panel. Whether or not two points are touched on the touch panel TP is determined based upon a resistance value between terminals opposing each other. When it is determined that two points are touched, the distances between touched two points XDual and YDual are detected. In this situation, the distances between touched two points XDual and YDual are detected based upon the resistance value of the opposing terminals and a pressing force (contact resistance value) of the touch input points.

Claims

1. A touch panel apparatus comprising:

a touch panel having two resistance films, each having a pair of electrode terminals at edge side portions opposing each other, the two resistance films closely opposing each other to be capable of being in contact with each other so that the pair of electrode terminals are vertically perpendicular to each other;

a between-terminal resistance measuring circuit designed to measure a resistance value of the pair of electrode terminals;

a two-point touch determining circuit designed to determine whether or not two points are touched on the touch panel based upon the resistance value measured by the between-terminal resistance measuring circuit;

a pressing force detector adapted to detect a pressing force of a touch input when the two-point touch determining circuit determines that the two points are touched;

a two-point distance detector adapted to detect a distance between the two points based upon the resistance value measured by the between-terminal resistance measuring circuit and the pressing force measured by the pressing force detector, when the two-point touch determining circuit determines that the two points are touched;

wherein the two-point distance detector comprises;

a reference value calculating circuit designed to calculate a reference value of the distance between the two points based upon a difference between the resistance value measured by the between-terminal resistance measuring circuit when the touch panel is not touched and the resistance value measured by the between-terminal resistance measuring circuit when the touch panel is touched; and

a correcting circuit designed to increase the reference value of the distance between the two points calculated by the reference value calculating circuit, as the pressing force detected by the pressing force detector is smaller.

4. The touch panel apparatus according to any one of claims 1, 2 and 3,

wherein when the two-point touch determining circuit determines that the two points are touched, the pressing force detector detects a pressing parameter having a correlation with a pressing force of the touch input and having a same or a substantially same degree of the correlation with the pressing force of each point.

2. A touch panel apparatus comprising,

a touch panel composed of two resistance films, each having a pair of electrode terminals at edge side portions opposing each other, the two resistance films closely opposing each other to be capable of being in contact with each other so that the pair of electrode terminals are vertically perpendicular to each other;

a first voltage detector adapted to, with a power-supply voltage being applied between the pair of the electrode terminals of one of the resistance films and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detect a voltage of any one of the pair of electrode terminals of the other of the resistance films;

a second voltage detector adapted to, with a power-supply voltage being applied, through a resistance, between the pair of the electrode terminals of one of the resistance films and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detect a voltage of any one of the pair of electrode terminals of the other of the resistance films;

a two-point touch determining circuit designed to determine whether or not two points are touched on the touch panel based upon a ratio of the voltage detected by the first voltage detector and the voltage detected by the second voltage detector;

a pressing force detector adapted to detect a pressing force of a touch input when the two-point touch determining circuit determines that the two points are touched; and

a two-point distance detector adapted to detect a distance between the two points based upon the ratio of the voltage detected by the first voltage detector and the voltage detected by the second voltage detector, and the pressing force measured by the pressing force detector, when the two-point touch determining circuit determines that the two points are touched.

3. The touch panel apparatus according to claim 2, wherein the two-point distance detector comprises:

a reference value calculating circuit designed to calculate a reference value of the distance between the two points based upon a difference between the ratio of the voltage detected by the first voltage detector and the voltage detected by the second voltage detector when one point is touched on the touch panel, and the ratio of the voltage detected by the first voltage detector and the voltage detected by the second voltage detector when the two points are touched on the touch panel; and

a correcting circuit designed to increase the reference value of the distance between the two points calculated by the reference value calculating circuit, as the pressing force detected by the pressing force detector is smaller.

5. A method for detecting a distance between touch input points of a touch panel, the method comprising:

as a first voltage detecting step, with a power-supply voltage being applied between a pair of the electrode terminals arranged at edge side portions opposing each other in each of two resistance films in a touch panel, the two resistance films closely opposing each other to be capable of being in contact with each other so that the pair of electrode terminals are vertically perpendicular to each other, and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detecting a voltage of any one of the pair of electrode terminals of the other of the resistance films;

as a second voltage detecting step, with a power-supply voltage being applied, through a resistance, between the pair of the electrode terminals of one of the resistance films and with the pair of the electrode terminals of the other of the resistance films being short-circuited, detecting a voltage of any one of the pair of electrode terminals of the other of the resistance films;

determining whether or not two points are touched on the touch panel based upon a ratio of the voltage detected by the first voltage detecting step and the voltage detected by the second voltage detecting step;

detecting a pressing force of a touch input when the two-point touch determining step determines that the two points are touched; and

detecting a distance between the two points based upon the ratio of the voltage detected by the first voltage detecting step and the voltage detected by the second voltage detecting step, and the pressing force measured by the pressing force detecting step, when the two-point touch determining step determines that the two points are touched.