Touch sensing device

Patent metadata

Field	Value
Publication number	US-9965081-B2
Application number	US-201514696755-A
Country	US
Kind code	B2
Filing date	Apr 27, 2015
Priority date	Apr 25, 2014
Publication date	May 8, 2018
Grant date	May 8, 2018

Abstract

A device for sensing a touch by measuring a variation in capacitance according to a contact of an object, and measuring a contact position of the object is provided. The device includes a touch screen panel comprising grid electrodes forming a plurality of electrode patterns, the grid electrodes serving as Tx antennas or Rx antennas, a Tx circuit unit connected with the grid electrode to apply an electric signal to the touch screen panel unit, an Rx circuit unit connected with the grid electrodes to sense variations in the capacitance in the plurality of electrode patterns, and a controller configured to control the touch screen panel unit, the Tx circuit unit, and the Rx circuit unit. The Rx circuit unit includes a first operational amplifier, a first feedback capacitor, and a second feedback capacitor. The first feedback capacitor and the second feedback capacitor are connected with the first operational amplifier. Both terminals of the first feedback capacitor and the first operational amplifier are connected through a first switching unit. The first switching unit includes a 1-1 switch and a 1-2 switch, which are controlled to be short-circuited at a first phase of the electric signal. Both terminals of the second feedback capacitor and the first operational amplifier are connected through a second switching unit. The second switching unit includes a 2-1 switch and a 2-2 switch, which are controlled to be short-circuited at a second phase of the electric signal. The controller is further configured to short-circuit the first switching unit and the second switching unit, at different times, to store charges in each of the first feedback capacitor and the second feedback capacitor.

First claim

What is claimed is:

1. A device for sensing a touch, which measures a variation in capacitance according to a contact of an object, and measures a contact position of the object, the device comprising:
a touch screen panel comprising grid electrodes forming a plurality of electrode patterns, the grid electrodes serving as Tx antennas or Rx antennas;
a Tx circuit unit connected with the grid electrode to apply an electric signal to the touch screen panel unit;
an Rx circuit unit connected with the grid electrodes to sense variations in the capacitance in the plurality of electrode patterns; and
a controller configured to control the Tx circuit unit and the Rx circuit unit,
wherein the Rx circuit unit comprises a first operational amplifier, a first feedback capacitor, and a second feedback capacitor,
the first feedback capacitor and the second feedback capacitor are connected with the first operational amplifier, and
both terminals of the first feedback capacitor and the first operational amplifier are connected through a first switching unit,
wherein the first switching unit comprises a switch, which is controlled to be short-circuited during a first time period, which is a period that a positive charge is applied to the Rx circuit unit according to a positive parity signal generated by the Tx circuit unit, such that the positive charge is applied to the first feedback capacitor,
wherein both terminals of the second feedback capacitor and the first operational amplifier are connected through a second switching unit,
wherein the second switching unit comprises a switch, which is controlled to be short-circuited during a second time period, which is a period that a negative charge is applied to the Rx circuit unit according to a negative parity signal generated by the Tx circuit unit,
wherein the controller is further configured to short-circuit the first switching unit and the second switching unit, at different times, to store charges in each of the first feedback capacitor and the second feedback capacitor,
wherein the Rx circuit unit includes an integrator,
wherein the integrator includes an offset compensation capacitor which is charged during the first time period and the second time period, and discharged during a third time period which is a period that the first switching unit and the second switching unit are open, and
wherein the controller measures the contact position of the object based on charge discharged from the integrator.

2. The device of claim 1 , wherein the controller makes a control so that a terminal of the first feedback capacitor connected with a negative input terminal of the first operational amplifier and a terminal of the second feedback capacitor connected with an output terminal of the first operational amplifier are connected with an output terminal of the Rx circuit unit, makes a control so that the other terminals of the first feedback capacitor and the second capacitor are connected with a ground or a constant voltage power supply, respectively, and makes a control so that the charges charged in the first feedback capacitor and the second feedback capacitor are output while the switches of the first switching unit and the second switching unit are open.

3. The device of claim 2 , wherein a terminal connected with a negative input terminal of the first operational amplifier and the terminal of the second feedback capacitor connected with the output terminal of the first operational amplifier are connected by a third switching unit during the third time period by the controller, and
the controller makes a control so that the charges charged in the first feedback capacitor and the second feedback capacitor are output while the third switching unit are shorted.

4. The device of claim 1 , wherein the controller makes a control so that a terminal of the first feedback capacitor connected with a negative input terminal of the first operational amplifier and a terminal of the second feedback capacitor connected with a negative input terminal of the first operational amplifier are connected with each other, makes a control so that the other terminal of the first feedback capacitor is connected with a ground or a constant voltage power supply, makes a control so that the other terminal of the second feedback capacitor is connected with an output terminal of the Rx circuit unit, and makes a control so that the charges charged in the first feedback capacitor and the second feedback capacitor are output while the switches of the first switching unit and the second switching unit are open.

5. The device of claim 4 , wherein a terminal of the first feedback capacitor connected with a negative input terminal of the first operational amplifier and a terminal of the second feedback capacitor connected with the negative input terminal of the first operational amplifier are connected through a first switch of a third switching unit which is controlled to be short-circuited during the third time period by the controller,
the other terminal of the second feedback capacitor is connected with an output terminal of the Rx circuit unit through a second switch of the third switching unit which is controlled to be short-circuited during the third time period by the controller, and
the controller makes a control so that charges charged in the first feedback capacitor and the second feedback capacitor are output by controlling the third switching unit so that the third switching unit is short-circuited.

6. The device of claim 1 , wherein the electric signal generated by the Tx circuit unit includes the positive parity signal and the negative parity signal, and
the controller makes a control so that charges generated by the positive parity signal are charged in the first feedback capacitor, and
charges generated by the negative parity signal are charged in the second feedback capacitor.

7. The device of claim 6 , wherein the controller makes a control so that the first feedback capacitor and the second feedback capacitor are connected in parallel to output charges charged in the first feedback capacitor and the second feedback capacitor.

8. The device of claim 6 , wherein the controller makes a control so that the first feedback capacitor and the second feedback capacitor are serially connected to output charges charged in the first feedback capacitor and the second feedback capacitor.

9. A device for sensing a touch, which measures a variation in capacitance according to a contact of an object, and measures a contact position of the object, the device comprising:
a touch screen panel comprising grid electrodes forming a plurality of electrode patterns, the grid electrodes servicing as Tx antennas or Rx antennas;
a Tx circuit unit connected with the grid electrode to apply an electric signal to the touch screen panel unit; and
an Rx circuit unit connected with the grid electrodes to sense variations in capacitance in the plurality of electrode patterns,
wherein the Rx circuit unit comprises:
a first integrator including a first feedback capacitor and a second feedback capacitor, wherein the first feedback capacitor and the second feedback capacitor store charges according to a positive signal and a negative signal input to the Rx circuit, respectively; and
a second integrator that integrates the charges of the first feedback capacitor and the second feedback capacitor with charges of an offset compensation capacitor having predetermined charges stored,

wherein the offset compensation capacitor, which is charged during a first time period and a second time period, and which is discharged during a third time period which is a period that the first switching unit and the second switching unit are open,
wherein th

Assignees

• Samsung Electronics Co Ltd
• Korean Advanced Institute Of Science And Tech
• Samsung Electronics Co Ltd
• Korea Advanced Inst Sci & Tech

Inventors

• Park Sung-Soo
• Park Chang-Byung
• Cho Gyu-Hyeong

Classifications

• G06F3/0418 Primary

  for error correction or compensation, e.g. based on parallax, calibration or alignment · CPC title

• G06F3/0416 Primary

  Control or interface arrangements specially adapted for digitisers · CPC title

• G06F3/044

  by capacitive means · CPC title

• G06F3/0446

  using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes · CPC title