Detection apparatus, display apparatus, and detection method
A detection apparatus includes a first substrate, a first electrode, a plurality of second electrodes, a detection controller, and a second electrode controller. The first electrode is disposed on the first substrate. The second electrodes have an area smaller than the area of the first electrode and overlap the first electrode. The detection controller is coupled to the first electrode and detects a detection signal corresponding to a capacitance change in the first electrode. The second electrode controller supplies, to some of second electrodes in the second electrodes, a guard signal for suppressing a capacitance change in overlapping areas of the first electrode overlapping the respective second electrodes.
1. A detection apparatus comprising:
a first substrate;
a first electrode disposed on the first substrate;
a plurality of second electrodes having an area smaller than an area of the first electrode and overlapping the first electrode;
a detection controller coupled to the first electrode and configured to detect a detection signal corresponding to a capacitance change in the first electrode; and
a second electrode controller configured to supply, to some of second electrodes in the second electrodes, a guard signal for suppressing a capacitance change in overlapping areas of the first electrode overlapping the respective second electrodes, wherein
the second electrode controller is configured to bring second electrodes serving as a first selection target out of the second electrodes into a floating state where an electric potential is not fixed and is configured to supply the guard signal to second electrodes serving as a second selection target not included in the first selection target,
the second electrode controller is configured to perform a first selection operation for bringing the second electrodes serving as the first selection target into a floating state and is configured to perform a second selection operation for bringing the second electrodes serving as the second selection target into a floating state at a timing different from a timing of the first selection operation,
a first detection signal is output from the first electrode to the detection controller in the first selection operation, and a second detection signal is output from the first electrode to the detection controller in the second selection operation, and
the detection controller includes a calculator configured to calculate difference between the first detection signal and the second detection signal.
2. The detection apparatus according to claim 1 , wherein the detection controller includes a calculator configured to calculate the capacitance change in each of the overlapping areas based on the detection signal supplied from the first electrode.
3. The detection apparatus according to claim 1 , wherein the detection controller is configured to supply a detection drive signal to the first electrode and is configured to be supplied with the detection signal due to the detection drive signal from the first electrode.
4. The detection apparatus according to claim 1 , wherein the second electrodes are provided in a row-column configuration overlapping the first electrode.
5. The detection apparatus according to claim 1 , wherein the second electrode controller is configured to perform the first selection operation and the second selection operation at successive timings.
6. The detection apparatus according to claim 1 , wherein the detection controller is configured to provide signals having the same polarity to the first electrode in the first selection operation and the second selection operation.
7. The detection apparatus according to claim 1 , wherein
the second electrode controller is configured to select a first group of the second electrodes as a first selection target and select a second group of the second electrodes as a second selection target at a first timing,
the second electrode controller is configured to select a third group of the second electrodes as the first selection target and select a fourth group of the second electrodes as the second selection target at a second timing,
the second electrode controller is configured to bring the first selection target into the floating state and supply the guard signal to the second selection target,
the first group of the second electrodes is equal to the third group of the second electrodes, and
the second group of the second electrodes is equal to the fourth group of the second electrodes.
8. The detection apparatus according to claim 1 , wherein the second electrode controller includes a selection signal generator configured to generate a selection signal for selecting the second electrodes and an inversion circuit configured to generate a signal by inverting a high level part and a low level part of the selection signal.
9. The detection apparatus according to claim 1 , wherein
a plurality of the first electrodes are arrayed in a row-column configuration,
the first electrodes are coupled to respective coupling wires, and
the detection signal is output to the detection controller via the coupling wires.
10. The detection apparatus according to claim 1 , wherein the second electrode controller selects the second electrodes in units of a second electrode group including a plurality of second electrodes.
11. A display apparatus comprising:
the detection apparatus according to claim 1 ; and
a display layer configured to display an image.
12. The display apparatus according to claim 11 , wherein the display layer is controlled by the first electrode and the second electrodes.
13. The display apparatus according to claim 11 , wherein the first electrode is supplied with a display drive signal serving as a common potential for a plurality of pixels, and each the second electrodes is supplied with respective pixel signals in a display operation.
14. The display apparatus according to claim 11 , wherein the second electrodes, the first electrode, and the display layer are provided in order from a display surface on which the image is displayed.
15. A detection method performed by a detection apparatus including:
a first substrate;
a first electrode disposed on the first substrate;
a plurality of second electrodes having an area smaller than the area of the first electrode and overlapping the first electrode;
a detection controller coupled to the first electrode and configured to detect a detection signal corresponding to a capacitance change in the first electrode; and
a second electrode controller configured to select some of second electrodes in the second electrodes, the detection method comprising step of
supplying, to the some of the second electrodes by the second electrode controller, a guard signal for suppressing a capacitance change in overlapping areas of the first electrode overlapping the respective second electrodes and supplying a detection signal corresponding to the capacitance change in the first electrode to the detection controller, wherein
the second electrode controller is configured to bring second electrodes serving as a first selection target out of the second electrodes into a floating state where an electric potential is not fixed and is configured to supply the guard signal to second electrodes serving as a second selection target not included in the first selection target,
the second electrode controller is configured to perform a first selection operation for bringing the second electrodes serving as the first selection target into a floating state and is configured to perform a second selection operation for bringing the second electrodes serving as the second selection target into a floating state at a timing different from a timing of the first selection operation,
a first detection signal is output from the first electrode to the detection controller in the first selection operation, and a second detection signal is output from the first electrode to the detection controller in the second selection operation, and
the detection controller includes a calculator configured to calculate difference between the first detection signal and the second detection signal.
16. A detection apparatus comprising:
a first substrate;
a first electrode disposed on the first substrate;
a plurality of second electrodes having an area smaller than an area of the first electrode and overlapping the first electrode;
a detection controller coupled to the first electrode and configured to detect a detection signal corresponding to a capacitance change in the first electrode; and
a second electrode controller configured to supply, to some of second electrodes in the second electrodes, a guard signal for suppressing a capacitance change in overlapping areas of the first electrode overlapping the respective second electrodes, wherein
the second electrode controller is configured to bring second electrodes serving as a first selection target out of the second electrodes into a floating state where an electric potential is not fixed and is configured to supply the guard signal to second electrodes serving as a second selection target not included in the first selection target,
wherein the second electrode controller is configured to select the second electrodes serving as the first selection target and the second electrodes serving as the second selection target corresponding to a selection signal that is based on a predetermined code, and
the selection signal based on the predetermined code is a signal that is based on a Hadamard matrix.