Display device with touch panel and method for controlling display device with touch panel
A display device with a touch panel starts a first touch detection process within an extension period, and ends the first touch detection process before a normal drive period starts. The display device with a touch panel performs a process of outputting first report data when a length of the extension period is equal to or longer than a predetermined length. The display device with a touch panel performs, after the normal drive period starts, a second touch detection process, a writing process, and a process of outputting second report data.
1 . A display device with a touch panel that operates at a variable frame rate, wherein
the variable frame rate is achieved by changing a length of a first period of one frame period that includes the first period and a second period,
the display device comprising:
the touch panel including pixel electrodes and a plurality of touch detection electrodes; and
a control unit configured to:
perform a writing process of writing data signals to the pixel electrodes,
perform a touch detection process for touches detected by the touch panel, wherein the touch detection process comprises at least a first touch detection process of acquiring first detection signals from the plurality of touch detection electrodes and a second touch detection process of acquiring second detection signals from the plurality of touch detection electrodes,
start the first touch detection process within the first period,
end the first touch detection process before a beginning of the second period that follows the first period,
forgo outputting first report data reporting a detection result of the first touch detection process when the length of the first period is shorter than a length of a reference period obtained by adding a time required for acquiring the first and second detection signals from the plurality of touch detection electrodes to a length of a vertical blanking period, and output the first report data when the length of the first period is equal to, or longer than, the length of the reference period, and
perform, after the second period starts, the second touch detection process, the writing process, and a process of outputting second report data reporting a detection result of the second touch detection process.
2 . The display device with a touch panel according to claim 1 , wherein
the control unit is configured to end the first touch detection process, within the first period, when a length of a period, in which the first touch detection process is performed, becomes equal to, or longer than, the length of the reference period.
3 . The display device with a touch panel according to claim 1 , wherein
the control unit is further configured to perform a process of discarding the detection result of the first touch detection process when the length of the first period is shorter than the length of the reference period.