Liquid crystal display device and method of driving the same

• US 10,001,852 B2
• Filed: 05/14/2013
• Issued: 06/19/2018
• Est. Priority Date: 05/18/2012
• Status: Active Grant

• Current Assignee: LG Display Co., Ltd.
• Original Assignee: LG Display Co., Ltd.
• Inventors: Kim, HoonBae
• Primary Examiner(s): Lin, Hang
• Application Number:
  US13/893,497
• Publication Number:
  US 20130307820A1
• Time in Patent Office: 1,862 Days
• Field of Search: 345173-174
• CPC Class Codes: G06F 3/0412 Digitisers structurally integrated in a display
• CPC Class Codes: G06F 3/0443 using a single layer of sensing electrodes
• CPC Class Codes: G06F 3/0446 using a grid-like structure of electrodes in at least two directions, e.g. using row and column electrodes
• CPC Class Codes: G09G 2300/0426 Layout of electrodes and connections
• CPC Class Codes: G09G 2320/0219 Reducing feedthrough effects in active matrix panels, i.e. voltage changes on the scan electrode influencing the pixel voltage due to capacitive coupling
• CPC Class Codes: G09G 2330/06 Handling electromagnetic interferences [EMI], covering emitted as well as received electromagnetic radiation
• CPC Class Codes: G09G 3/3655 Details of drivers for counter electrodes, e.g. common electrodes for pixel capacitors or supplementary storage capacitors
• CPC Class Codes: G09G 3/3677 suitable for active matrices only

Abstract

Disclosed is an LCD device and a method of driving the same. The LCD device includes a liquid crystal panel configured to comprise a TFT substrate and a color filter substrate; a touch panel configured to comprise a plurality of electrode units parallel to the gate lines to detect a touch, each of the electrode units comprising a plurality of driving electrodes and a plurality of receiving electrodes; a common voltage generator configured to generate a common voltage; a touch sensing unit configured to supply the common voltage to the electrode units and sequentially supply a driving voltage to driving electrodes formed in scanned electrode units, corresponding to scanned gate lines which have received a scan signal for one frame period, to detect a touch; and a driving voltage generator configured to generate the driving voltage.

Claims

1. A liquid crystal display (LCD) device comprising:

a liquid crystal panel configured to comprise a TFT substrate and a color filter substrate which are coupled to each other with a liquid crystal layer therebetween;

a touch panel configured to comprise a plurality of electrode units parallel to the gate lines to detect a touch, each of the electrode units comprising a plurality of driving electrodes, formed in parallel to data lines formed in the TFT substrate, and a plurality of receiving electrodes formed in parallel to gate lines formed in the TFT substrate to intersect the driving electrodes;

a common voltage generator configured to generate a common voltage;

a touch sensing circuit configured to supply the common voltage to the electrode units and supply a driving voltage to driving electrodes formed in scanned electrode units, corresponding to scanned gate lines which have received a scan signal for one frame period, to detect a touch; and

a driving voltage generator configured to generate the driving voltage,

wherein the driving electrodes configuring one of the electrode units are separate from the driving electrodes configuring another of the electrode units in a direction of the data lines;

wherein the driving electrodes of each of the respective electrode units are parallel to each other in a direction of the gate lines, and the gate lines are perpendicular to the data lines;

wherein there are at least three electrode units in a direction parallel to the data lines;

wherein the touch sensing circuit includes a switching circuit and a touch sync signal generator;

wherein the switching circuit includes;

a plurality of driving electrode switches configured to connect the driving electrodes to the common voltage generated by the common voltage generator and to the driving voltage generated by the driving voltage generator; and

a plurality of receiving electrode switches configured to connect the receiving electrodes to the common voltage generated by the common voltage generator;

wherein the touch sync signal generator generates a touch sync signal for controlling an operation of the switching unit;

wherein the touch sync signal generator transfers a first touch sync signal to at least two switches among the driving electrode switches and receiving electrode switches, the first touch sync signal connecting the at least two switches to the common voltage generator;

wherein the touch sync signal generator transfers a second touch sync signal to the at least two switches among the driving electrode switches and receiving electrode switches, the second touch sync signal sequentially connecting the at least two switches to the driving voltage generator;

wherein when the common voltage is supplied to the driving electrodes and the receiving electrodes of one of the electrode units, the touch sensing circuit supplies the driving voltage to the driving electrodes configuring the another electrode unit to detect a touch in the another electrode unit, and

wherein the touch sensing circuit further comprises;

a sensing signal receiver configured to determine whether there is a touch, the sensing signal receiver including;

a touch sensing part that determines whether there is the touch by using sensing signals received from the receiving electrodes; and

a plurality of sensing switches that are connected between the touch sensing part and each of the receiving electrodes,

wherein the plurality of sensing switches disconnect the touch sensing part from each of the receiving electrodes that are connected to the common voltage generated by the common voltage generator by the plurality of receiving electrode switches, to thereby avoid degradation of the touch sensing part.

2. The LCD device of claim 1, wherein,

the driving electrodes and the receiving electrodes configuring the touch panel are formed on the same layer of the TFT substrate.

3. The LCD device of claim 1, wherein

the switching circuit is configured to perform a common voltage transferring operation that connects the electrode units to the common voltage generator and perform a driving voltage transferring operation where the driving electrodes formed in the scanned electrode unit connected to the common voltage generator through the common voltage transferring operation are sequentially connected to the driving voltage generator.

4. The LCD device of claim 3, wherein,

the touch sync signal generator sequentially transfers the second touch sync signal, which allows the driving electrodes formed in the scanned electrode unit to be sequentially connected to the driving voltage generator, to scanned switches of the switches connected to the scanned electrode unit corresponding to the scanned gate lines, and

the touch sync signal generator transfers the first touch sync signal, which allows the driving electrode units connected to the switches to be connected to the common voltage generator, to the switches, the second touch sync signal being not inputted to the switches.

5. The LCD device of claim 4, wherein,

the touch sync signal generator transfers a third touch sync signal to scan input sensing switches connected to scan input receiving electrodes formed in a scan input electrode unit connected to the scan input switches among the sensing switches, the third touch sync signal allowing the scan input sensing switch to be separated from the touch sensing part.

6. A method of driving a liquid crystal display (LCD) device, the method comprising:

supplying a common voltage to a plurality of electrode units parallel to a plurality of gate lines, each of the electrode units comprising a plurality of driving electrodes, formed in parallel to a plurality of data lines, and a plurality of receiving electrodes formed in parallel to the gate lines to intersect the driving electrodes, wherein the driving electrodes configuring one of the electrode units are separate from the driving electrodes configuring another of the electrode units in a direction of the data lines; and

supplying a driving voltage to driving electrodes formed in scanned electrode units, corresponding to scanned gate lines which have received a scan signal for one frame period, to detect a touch while the common voltage is supplied to the electrode units,

wherein the driving electrodes of each of the respective electrode units are parallel to each other in a direction of the gate lines, and the gate lines are perpendicular to the data lines;

wherein there are at least three electrode units in a direction parallel to the data lines;

wherein when the common voltage is supplied to the driving electrodes and the receiving electrodes of one of the electrode units, a touch sensing circuit supplies the driving voltage to the driving electrodes configuring the another electrode unit to detect a touch in the another electrode unit; and

wherein the touch sensing circuit includes a switching circuit and a touch sync signal generator;

wherein the switching circuit includes;

a plurality of driving electrode switches configured to connect the driving electrodes to the common voltage generated by a common voltage generator and to the driving voltage generated by a driving voltage generator; and

a plurality of receiving electrode switches configured to connect the receiving electrodes to the common voltage generated by the common voltage generator,

wherein the touch sync signal generator generates a touch sync signal for controlling an operation of the switching unit;

wherein the touch sync signal generator transfers a first touch sync signal to at least two switches among the driving electrode switches and receiving electrode switches, the first touch sync signal connecting the at least two switches to the common voltage generator;

wherein the touch sync signal generator transfers a second touch sync signal to the at least two switches among the driving electrode switches and receiving electrode switches, the second touch sync signal sequentially connecting the at least two switches to the driving voltage generator, and

wherein the touch sensing circuit further comprises;

a sensing signal receiver configured to determine whether there is a touch, the sensing signal receiver including;

a touch sensing part that determines whether there is the touch by using sensing signals received from the receiving electrodes; and

a plurality of sensing switches that are connected between the touch sensing part and each of the receiving electrodes,

wherein the plurality of sensing switches disconnect the touch sensing part from each of the receiving electrodes that are connected to the common voltage generated by the common voltage generator by the plurality of receiving electrode switches, to thereby avoid degradation of the touch sensing part.

7. The method of claim 6, wherein,

the driving voltage has a voltage, corresponding to the common voltage, as a low-level voltage, and has a voltage greater than the low-level voltage as a high-level voltage.

8. The method of claim 6, wherein,

each of the electrode units is formed in a liquid crystal panel in correspondence with a plurality of gate lines, and

the common voltage is continuously supplied to all of the electrode units except a electrode unit receiving the driving voltage.

9. The method of claim 6, wherein the supplying a driving voltage to detect a touch comprises:

sequentially supplying the driving voltage to driving electrodes formed in one of the scanned electrode units, and determining whether there is a touch by using a plurality of sensing signals generated from a plurality of receiving electrodes formed in the one scanned electrode unit; and

sequentially supplying the driving voltage to driving electrodes formed in another scanned electrode unit, and determining whether there is a touch by using a plurality of sensing signals generated from a plurality of receiving electrodes formed in the other scanned electrode unit.