Synaptics Japan Gk

Synaptics Display Devices Gk

Isao Munechika

One display frame period is divided into one or a plurality of display driving periods and non-display driving periods, and immediately before transition from the non-display driving period to the display driving period, a dummy driving period is inserted. During the dummy driving period, using dummy data changed from display data at the time of driving stop of a signal electrode during the non-display driving period, driving of the signal electrode starts. Thereafter, a display line is selected, and, using the display data corresponding to each display line selected, the signal electrode is driven.

Driver IC for a display panel with touch device with display state timing in accordance with differing driving periods

A semiconductor device connected to the display panel including the in-cell type touch sensor is configured as follows. The semiconductor device includes a driving circuit of the display panel, a touch sensing circuit of the touch sensor, a power supply circuit that supplies a power source to these circuits, and a bias control circuit that controls a bias current flowing through these circuits. The semiconductor device is able to perform a time-division operation in which one frame period of display is divided into a plurality of display driving periods and sensing periods. In the display driving periods, the supply of power to the touch sensing circuit is suppressed, and/or a bias current is reduced. In the sensing periods, the supply of power to the driving circuit is suppressed, and/or a bias current is reduced.

Semiconductor device

The driver IC includes: a control circuit operable to perform control for creating the timing of detection by a touch panel in a non-display drive period during which the action of a drive circuit remains stopped, and for creating a display drive period during which the drive circuit drives the display panel, and the non-display drive period; and a data RAM operable to hold display data of more than one display line, but smaller than one display frame in capacity. The control circuit performs control for alternately creating the display and non-display drive periods by repeating a memory-addressing operation for writing display data supplied from outside into the RAM and reading the display data from the RAM at a speed faster than the writing speed to provide the read data to the drive circuit two or more times in a period of one display frame according to a wraparound method.

Driver IC and display device

The drive circuit operable to output a drive pulse pattern to drive electrodes of a touch panel is arranged so that it can change the pulse frequency of the drive pulse pattern for each drive electrode. The detection circuit operable to detect signal changes arising on detection electrodes of the touch panel for each drive pulse pattern output by the drive circuit is arranged so that it can change the sampling frequency of signal change for each detection electrode. The range to make higher the pulse frequency of the drive pulse pattern for each drive electrode, and the sampling frequency of signal change for each detection electrode is variably controlled according to a touch position where a touch has been detected by use of a detection signal detected by the detection circuit.

Growing community of inventors

Tokyo, Japan

Isao Munechika