Touch screen driver circuit and touch sensor display device

Patent metadata

Field	Value
Publication number	US-2020183539-A1
Application number	US-201916693002-A
Country	US
Kind code	A1
Filing date	Nov 22, 2019
Priority date	Dec 10, 2018
Publication date	Jun 11, 2020
Grant date	—

Abstract

A touchscreen driver circuit and a touch sensor display device are discussed. The touch sensor display device and the touch sensing method can improve touch sensitivity and improve touch sensitivity and the uniformity of a touch sensing signal while reducing the size of a circuit area.

First claim

What is claimed is:

1 . A touch sensor display device comprising:
a display panel in which a plurality of gate lines, a plurality of data lines, a plurality of sensing lines, and a plurality of subpixels are arranged; a touch panel disposed within the display panel; a gate driver circuit disposed on a side of the display panel to drive the plurality of gate lines; a data driver circuit disposed on a side of the display panel to drive the plurality of data lines; a touchscreen driver circuit disposed on a side of the display panel to drive the plurality of sensing lines, wherein the touchscreen driver circuit includes:
a polarity control circuit configured to control a polarity of a touch sensing signal, transferred through the plurality of sensing lines, by dividing the touch sensing signal into a plurality of signals,
an integrator circuit configured to charge a voltage output from the polarity control circuit, and
a sampling circuit configured to generate a sensing output voltage by sampling the voltage charged in the integrator circuit; and
a controller configured to control signals applied to the gate driver circuit, the data driver circuit, and the touchscreen driver circuit.

2 . The touch sensor display device according to claim 1 , wherein the polarity control circuit includes:
a plurality of voltage followers dividing the touch sensing signal into the plurality of signals and transferring the divided signals to another element; and an inverting amplifier connected to a voltage follower among the plurality of voltage followers.

3 . The touch sensor display device according to claim 2 , wherein each of the plurality of voltage followers comprises:
an operational amplifier having a non-inverting input terminal, to which the touch sensing signal is applied, and an inverting input terminal, to which an output signal is fed back.

4 . The touch sensor display device according to claim 2 , wherein the inverting amplifier comprises:
an operational amplifier receiving the touch sensing signal, transferred through a first resistor, through an inverting input terminal thereof, with a second resistor being connected between the inverting input terminal of the inverting amplifier and an output terminal, and a reference voltage being applied to a non-inverting input terminal of the inverting amplifier.

5 . The touch sensor display device according to claim 1 , wherein the integrator circuit includes:
a plurality of switches, connected to the polarity control circuit, and at least one capacitor, so that the integrator circuit charges the capacitor with the voltage, output from the polarity control circuit, in response to the plurality of switches being manipulated.

6 . The touch sensor display device according to claim 1 , wherein the sampling circuit includes:
an operational amplifier having an inverting input terminal, to which an output terminal of the integrator circuit is connected, and a non-inverting input terminal, to which a reference voltage is applied; and a feedback capacitor and a reset switch connected between the inverting input terminal and an output terminal of the operational amplifier in parallel.

7 . The touch sensor display device according to claim 1 , further comprising:
a calibration circuit compensating for offsets according to the plurality of sensing lines or offset deviations regarding circuit elements within the touchscreen driver circuit.

8 . The touch sensor display device according to claim 7 , wherein the calibration circuit feedbacks a threshold voltage of a transistor disposed in the display panel to the sensing output voltage, as a compensation value for calibration, according to the sensing lines.

9 . The touch sensor display device according to claim 1 , wherein the polarity control circuit includes:
a first polarity control circuit to which the touch sensing signal in a rising interval of a touch driving signal is applied; and a second polarity control circuit to which the touch sensing signal in a falling interval of the touch driving signal is applied.

10 . The touch sensor display device according to claim 9 , wherein the integrator circuit includes:
a first integrator circuit including a plurality of first switches, connected to the first polarity control circuit, and at least one first capacitor, to charge the first capacitor with a voltage, output from the first polarity control circuit, in response to the plurality of first switches being manipulated; and a second integrator circuit including a plurality of second switches, connected to the second polarity control circuit, and at least one second capacitor, to charge the second capacitor of the second integrator circuit with a voltage, output from the second polarity control circuit, in response to the plurality of second switches being manipulated.

11 . The touch sensor display device according to claim 10 , wherein the sampling circuit includes:
an operational amplifier receiving the voltage, output from the first integrator circuit, through an inverting input terminal thereof, and receiving the voltage, output from the second integrator circuit, through a non-inverting input terminal thereof; a feedback capacitor and a reset switch connected between the inverting input terminal and an output terminal of the operational amplifier in parallel; and a feedback capacitor and a reset switch connected between the non-inverting input terminal and the output terminal of the operational amplifier in parallel.

12 . A touchscreen driver circuit in a touch sensor display device including a display panel in which a plurality of subpixels are arranged, a gate driver circuit electrically connected to the display panel through a plurality of gate lines, a data driver circuit electrically connected to the display panel through a plurality of data lines, the touchscreen driver circuit configured to drive touch sensors in the display panel through a plurality of sensing lines, the touchscreen driver circuit comprising:
a polarity control circuit configured to control a polarity of a touch sensing signal, transferred through the plurality of sensing lines, by dividing the touch sensing signal into a plurality of signals; an integrator circuit configured to charge a voltage output from the polarity control circuit; and a sampling circuit configured to generate a sensing output voltage by sampling the voltage charged in the integrator circuit.

13 . The touchscreen driver circuit according to claim 12 , wherein the polarity control circuit includes:
a plurality of voltage followers configured to divide the touch sensing signal into the plurality of signals, and transfer the divided signals to another element; and an inverting amplifier connected to a voltage follower among the plurality of voltage followers.

14 . The touchscreen driver circuit according to claim 13 , wherein each of the plurality of voltage followers comprises:
an operational amplifier having a non-inverting input terminal, to which the touch sensing signal is applied, and an inverting input terminal, to which an output signal is fed back.

15 . The touchscreen driver circuit according to claim 13 , wherein the inverting amplifier comprises:
an operational amplifier receiving the touch sensing signal, transferred through a first resistor, through an inverting input terminal thereof, with a second resistor being connected between the inverting input terminal of the inverting amplifier and an output terminal, and a reference voltage being applied to a non-inverting input terminal of the inverting amplifier.

Assignees

• Lg Display Co Ltd

Inventors

• Kang Hyeongwon
• Lee Hongju

Classifications

• H03K17/962

  Capacitive touch switches · CPC title

• G06F3/0445

  using two or more layers of sensing electrodes, e.g. using two layers of electrodes separated by a dielectric layer · CPC title

• H03K2217/960735

  characterised by circuit details · CPC title

• G06F3/04184 Primary

  Synchronisation with the driving of the display or the backlighting unit to avoid interferences generated internally · CPC title

• G06F2203/04106

  Multi-sensing digitiser, i.e. digitiser using at least two different sensing technologies simultaneously or alternatively, e.g. for detecting pen and finger, for saving power or for improving position detection · CPC title