ON-SCREEN INPUT IMAGE DISPLAY SYSTEM

• US 20090115742A1
• Filed: 10/30/2008
• Published: 05/07/2009
• Est. Priority Date: 11/02/2007
• Status: Active Grant

• Current Assignee: Panasonic Intellectual Property Corporation of America (Panasonic Holdings Corporation)
• Original Assignee: Japan Display East Incorporated (Japan Display Incorporated)
• Inventors: Furuhashi, Tsutomu, MAMBA, Norio, Kinoshita, Masayoshi, Kumagai, Toshiyuki
• Granted Patent: US 8,081,168 B2
• 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 3/0444 using a single conductive element covering the whole sensing surface, e.g. by sensing the electrical current flowing at the corners

Abstract

A detection resolution is improved in a display device that employs an electrostatic capacity coupling type touch panel provided with a transparent conductive film serving as a detection film. A plurality of electrode terminals (102) is provided such that at least three electrode terminals (102) are aligned in each side of a detection transparent conductive film (101). A touch panel control circuit is provided for selecting one of two to four numbers of electrode terminals from among the plurality of electrode terminals (102) of the detection transparent conductive film (101), applying an AC signal provided from a signal source (105) through a current detection resistor (r) (103), and then detecting a current that flows through each of the selected electrode terminals.

Claims

1. An on-screen input image display system, comprising:

a touch panel for detecting two-dimensional coordinates of a touch position located on a display screen of a display device, the touch panel comprising a plurality of electrode terminals such that at least three electrode terminals are aligned in each side; and

a touch panel control circuit for selecting one of two to four numbers of electrode terminals from among the plurality of electrode terminals, and then applying an AC signal through a current detection resistor and detecting a current that flows through each of the selected electrode terminals,

wherein coordinate detection is performed in two separate periods so that in a first period of the two separate periods, a touched region is detected by selecting terminals at four corners from among the plurality of electrode terminals, and in a second period of the two separate periods, coordinates are detected by controlling electrodes selected in accordance with the region detected in the first period.

2. An on-screen input image display system according to claim 1, wherein, in the beginning of the coordinate detection, the touch panel control circuit detects a touched region similarly to that in the first period, and then repeats X-directional detection processing for detecting a horizontal coordinate and Y-directional detection processing for detecting a vertical coordinate to thereby continuously perform the coordinate detection.

3. An on-screen input image display system according to claim 2, wherein:

in the X-directional detection processing, the coordinate detection is performed by selecting one or two electrode terminals in each of two sides vertically facing each other in accordance with a region identified on the basis of coordinate detection results obtained in the first period or at a preceding timing; and

in the Y-directional detection processing, the coordinate detection is performed by selecting one or two electrode terminals in each of two sides horizontally facing each other in accordance with the region identified on the basis of the coordinate detection results obtained in the first period or at the preceding timing.

4. An on-screen input image display system according to claim 3, wherein:

in the X-directional detection processing, a touched region is determined by comparing a result of current detection obtained by selecting the electrode terminals in accordance with the region identified on the basis of the coordinate detection results obtained in the first period or at the preceding timing with an expected value range corresponding to the region; and

in the Y-directional detection processing, the touched region is determined by comparing a result of current detection obtained by selecting the electrode terminals in accordance with the region identified on the basis of the coordinate detection results obtained in the first period or at the preceding timing with an expected value region corresponding to the region.

5. An on-screen input image display system according to claim 4, wherein, in the touch panel, the X-directional detection processing and the Y-directional detection processing are controlled in accordance with sensor areas defined in advance.

6. An on-screen input image display system according to claim 1, wherein the touch panel is an electrostatic capacity coupling type touch panel employing a detection transparent conductive film arranged on a display screen of the display device.

7. An on-screen input image display system comprising a touch panel for detecting two-dimensional coordinates of a touch position located on a display screen of a display device,

the touch panel comprising:

a plurality of first detection terminals provided in a first region located at least a predetermined distance away from a center point of the touch panel; and

a plurality of second detection terminals provided in a second region within a predetermined distance from the center point of the touch panel, wherein;

in the touch panel, in a first period within a touch position detection period, a touch position is determined by the plurality of first detection terminals; and

in a second period within the touch position detection period, depending on the touch position detected in the first period, determination of whether the touch position is detected by the plurality of second detection terminals or not, or selection of a second detection terminals used for detecting the touch position from among the plurality of second detection terminals is performed.