Display device with touch sensor
A common electrode for a display, which is originally provided in a liquid crystal display element, is also used as one (drive electrode) of a pair of electrodes for a touch sensor, and the other (detection-electrode-for-the-sensor) of the pair of electrodes is newly formed. An existing common drive signal as a drive signal for display is used in common for a drive signal for the touch sensor. A capacitance is formed between the common electrode and the detection-electrode-for-the-sensor, and touch detection is performed by utilizing a change of this capacitance caused by a finger touch of a user. Thus, a display device with a touch sensor is also applicable to a mobile device in which electric potential of the user is inconstant in many cases. The newly-provided electrode is only the detection-electrode-for-the-sensor, and it is unnecessary to newly prepare a drive signal for the touch sensor.
1. A display device comprising:
a pixel substrate;
a common electrode disposed on the pixel substrate;
a plurality of touch detecting electrodes configured to detect capacitance variation caused by a touch, the touch detecting electrodes being disposed on the pixel substrate in a region surrounding the common electrode;
an opposed substrate facing the pixel substrate;
at least one pixel electrode arranged between the pixel substrate and the opposed substrate; and
a display function layer interposed between the pixel substrate and the opposed substrate within an image display area,
wherein,
the common electrode and the touch detecting electrodes are coplanar,
the pixel electrode is used to drive the function layer to effect a display of an image;
the touch detecting electrodes and the common electrode are capacitively coupled to each other; and
the touch detecting electrodes are time-divisionally scanned.
2. The display device set forth in claim 1 , wherein each of the touch detecting electrodes are located outside of the image display area.
3. The display device set forth in claim 2 , wherein each of the touch detecting; electrodes are located along at least a side of the circumference of the image display area.
4. The display device set forth in claim 1 , wherein a metal shield is embedded in the pixel substrate within an area where the touch detecting electrodes are formed.
5. The display device set forth in claim 1 , wherein the common electrode functions not only as a drive electrode for image display but also as a drive electrode for touch detection.
6. A touch detecting unit for use with a display device, the display device comprising:
a pixel substrate;
an opposed substrate facing the pixel substrate;
at least one pixel electrode arranged between the pixel substrate and the opposed substrate;
a common electrode facing the at least one pixel electrode; and
a display function layer interposed between the pixel substrate and the opposed substrate within an image display area,
wherein,
the touch detecting unit comprises a plurality of touch detecting electrodes configured to detect capacitance variation caused by a touch, the touch detecting electrodes being disposed on the pixel substrate in a region surrounding the common electrode,
the common electrode functions not only as a drive electrode of image display but also as a drive electrode of touch detection,
the common electrode and the touch detecting electrodes are coplanar,
the pixel electrode is used to drive the function layer to effect a display of an image;
the touch detecting electrodes and the common electrode are capacitively coupled to each other; and
the touch detecting electrodes are time-divisionally scanned.
7. A display device comprising:
a pixel substrate;
an opposed substrate facing the pixel substrate;
at least one pixel electrode arranged between the pixel substrate and the opposed substrate;
a display function layer interposed between the pixel substrate and the opposed substrate within an image display area;
at least one common electrode spaced apart from the at least one pixel electrode; and
a plurality of touch detecting electrodes configured to detect capacitance variation caused by a touch, the touch detecting electrodes being spaced apart from the at least one pixel electrode, the touch detecting electrodes being disposed on the pixel substrate in a region surrounding the at least one common electrode,
wherein,
the at least one common electrode and the touch detecting electrodes are coplanar,
the pixel electrode is used to drive the function layer to effect a display of an image;
the touch detecting electrodes and the common electrode are capacitively coupled to each other; and
the touch detecting electrodes are time-divisionally scanned.
8. The display device set forth in claim 7 , wherein the at least one common electrode and the plurality of touch detecting electrodes are disposed on the pixel substrate.
9. The display device set forth in claim 7 , wherein voltages to be applied to the at least one common electrode are controlled so that image display and/or touch detection are performed.