KR101633174B1 - Touch sensing device and driving method thereof - Google Patents

Abstract

The present invention relates to a touch sensing device and a driving method thereof, and shortens the touch sensors by connecting sensor lines during a display driving period, and supplies a common voltage to the sensor lines through one end and the other end of the sensor lines. The sensor lines are disconnected during the touch sensor activation period. The first feeder and the second feeder supply the common voltage to both ends of the same sensor line while the sensor lines are connected to each other.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch sensing device and a method of driving the touch sensing device.

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a touch sensing device in which touch sensors are embedded in a pixel array and a driving method thereof.

A user interface (UI) enables a user (a user) to communicate with various electric or electronic devices, allowing the user to easily control the device as desired. Representative examples of the user interface include a keypad, a keyboard, a mouse, an on-screen display (OSD), a remote controller having infrared communication or radio frequency (RF) communication functions. User interface technology has been developed to enhance the user's sensibility and ease of operation. Recently, the user interface has evolved into a touch UI, a voice recognition UI, a 3D UI, and the like.

Touch UI is essential for portable information devices such as smart phones, and is being applied to notebook computers, computer monitors, and home appliances. 2. Description of the Related Art In recent years, a technology for incorporating touch sensors in a pixel array of a display panel (hereinafter referred to as "In-cell touch sensor") has been proposed. Incelel touch sensor technology can install touch sensors on the display panel without increasing the thickness of the display panel. These touch sensors are connected to the pixels through parasitic capacitance. The driving method includes a period for driving pixels (hereinafter referred to as a " display driving period ") and a period for driving the touch sensors (hereinafter referred to as" touch ") for reducing mutual influences due to coupling of pixels and touch sensors, Quot; sensor driving period ").

The Insel touch sensor technology utilizes the electrodes connected to the pixels of the display panel as the electrodes of the touch sensors. For example, the in-line touch sensor technology divides a common electrode for supplying a common voltage to pixels of a liquid crystal display device and utilizes the common electrode as an electrode of the touch sensors. However, the common voltage should be applied to all the pixels at the same voltage. However, if the common electrode is divided into the touch sensors, the common voltage may become non-uniform on the large screen, and the picture quality may be deteriorated.

Referring to FIGS. 1 to 3, the in-cell touch sensor technology divides the common electrode COM into a plurality of sensor electrodes C1 to C4. Sensor lines L1 to L4 are connected to sensor electrodes C1 to C4, respectively.

During the display driving period Td, the common voltage Vcom of the pixels is supplied to the sensor electrodes C1 to C4 through the sensor lines L1 to L4. During the touch sensor driving period Tt, the sensor driving signal Tdrv is supplied to the sensor electrodes C1 to C4 through the sensor lines L1 to L4.

The lengths of the sensor lines (L1 to L4) depend on the position of the touch sensor. Therefore, the delay time of the common voltage Vcom applied to the sensor electrodes C1 to C4 due to the length difference of the sensor lines L1 to L4 varies depending on the position of the touch sensor, resulting in non-uniform image quality.

For example, as shown in FIG. 3, the delay time of the common voltage Vcom applied to the first sensor electrode C1 through the first sensor line L1 may be delayed by the fourth sensor electrode L4 through the fourth sensor line L4. C4) of the common voltage Vcom. This is because the length of the first sensor line L1 is longer than that of the fourth sensor line L4 and the RC delay is larger. Therefore, even if the same voltage is applied to the first and fourth sensor lines L1 and L4, the voltage of the first sensor electrode C1 becomes lower than the voltage of the fourth sensor electrode C4. Due to the RC delay, the delay time of the sensor driving signal (Tdrv) also changes according to the position of the touch sensor.

In the case of a display device of a large screen, the length difference of the sensor lines (L1 to L4) becomes larger. Accordingly, the conventional Insel touch sensor technology can cause the common voltage (Vcom) applied through the sensor electrodes (C1 to C4) to be uneven during the display driving period (Td) in the display device on the large screen, have.

A large-screen display device has a large parasitic capacitance due to coupling between the in-line touch sensors and the pixels. Accordingly, when the size of the touch screen to which the in-cell touch sensor is applied is increased and the resolution is increased, the parasitic capacitance connected to the in-line touch sensors is increased, thereby degrading the touch sensitivity and the touch recognition accuracy. Accordingly, there is a need for a method of minimizing the parasitic capacitance of the touch sensors in order to apply the Insel touch sensor technology to a touch screen of a large screen display device.

The present invention provides a touch sensing device and a method of driving the same that can uniformize a common voltage applied to pixels in a display device including in-line touch sensors and improve touch sensitivity and accuracy of touch recognition.

The touch sensing device of the present invention includes signal lines connected to pixels; Sensor lines connected to the touch sensors; A first power feeder supplying a common voltage to one end of the sensor lines during a display driving period and supplying a touch driving signal to one end of the sensor lines during a touch sensor driving period; And a second power feeder for disconnecting the sensor lines during the touch sensor driving period by connecting the sensor lines during the display driving period to short-circuit the touch sensors and supply the common voltage from the other end of the sensor lines . Each of the sensor lines extends along the same direction between one end and the other end of each of the sensor lines. The first feeder and the second feeder supply the common voltage to both ends of the same sensor line while the sensor lines are connected to each other.

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The method of driving the touch sensing device includes connecting the sensor lines during a display driving period to short-circuit the touch sensors, and supplying a common voltage to the sensor lines through one end and the other end of the sensor lines; And separating the sensor lines during a touch sensor driving period and supplying a touch driving signal to one end of the sensor lines.

The present invention relates to a touch sensing device and a display device, and more particularly, to a display device in which a common electrode for supplying a common voltage to pixels is divided to form sensor electrodes of a plurality of touch sensors, And supplies a driving signal to the touch sensors. The present invention connects the sensor lines during the display driving period to supply common voltages across the sensor lines in a state where the touch sensors are shorted to each other, and separates the sensor lines during the touch sensor driving period. As a result, the touch sensing device of the present invention can uniformize the common voltage applied to the pixels in the display device including the in-line touch sensors.

The present invention supplies an AC signal having the same phase as a touch driving signal to signal wirings connected to a pixel in order to minimize a parasitic capacitance connected to the touch sensors during a touch sensor driving period. Therefore, the touch sensing device of the present invention can minimize the parasitic capacitance of the touch sensors.

The display device of the present invention can uniformize the common voltage of the pixels connected to the incelel touch sensors and minimize the parasitic capacitance of the touch sensors so that the display device including the insensitive touch sensors can be made large in size and the resolution of the touch screen can be increased .

1 is a view showing sensor lines connected to touch sensors.
2 is a waveform diagram showing a common voltage and a touch driving signal applied to the touch sensors in Insel-Touch technology.
FIG. 3 is a waveform diagram showing a common voltage at which a delay time varies according to a position of a touch sensor in Insel-Touch technology.
4 is a block diagram schematically showing a display apparatus according to the present invention.
5 and 6 are views illustrating capacitive touch sensors according to an embodiment of the present invention.
7 to 9 are waveform diagrams showing a pixel driving signal and a touch driving signal applied to the display device of the present invention.
10 is a waveform diagram showing various examples of the touch driving signal.
11 is a circuit diagram showing a driving circuit of a display device according to an embodiment of the present invention in detail.
FIGS. 12 and 13 are waveform diagrams showing a pixel driving signal and a touch driving signal output from the driving circuit shown in FIG.
FIG. 14 is an equivalent circuit diagram showing the mutual capacitance type touch sensors according to the embodiment of the present invention.
15 to 17 are views showing examples in which double power feeding means are connected to the touch sensors as shown in FIG.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

The display device of the present invention can be applied to a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), an organic light emitting display , An OLED, and an electrophoresis display (EPD). In the following embodiments, the liquid crystal display device is described as an example of the flat panel display device, but the present invention is not limited thereto. For example, the display device of the present invention may be any display device to which the in-line touch sensor technology is applicable.

A touch sensing apparatus of the present invention divides a common electrode for supplying a common voltage to pixels and embeds a plurality of touch sensors in a pixel array. The touch sensing device of the present invention uses a switching device to short-circuit the touch sensors during a display driving period to apply a common voltage Vcom to the pixels through sensor electrodes connected to each other in a state where the sensor electrodes are connected to each other do. The touch sensing device of the present invention applies touch driving signals to the touch sensors in a state where the touch sensors are separated by turning off the switching elements during the touch sensor driving period. During the touch sensor period, AC signals on the same level as the touch driving signal may be supplied to the signal lines connected to the pixels to minimize the influence of the parasitic capacitance connected to the pixels.

The common voltage exemplifies the common voltage applied to the pixels of the liquid crystal display in the following embodiments, but is not limited thereto. For example, the common voltage should be interpreted as the voltage commonly supplied to the pixels in the flat panel display, such as the high / low potential power supply voltage (VDD / VSS) commonly applied to the pixels of the organic light emitting diode display.

The touch sensor of the present invention refers to a capacitive type touch sensor that can be implemented with an in-cell touch sensor. Such a touch sensor may be divided into a self capacitance type or a mutual capacitance type.

Capacitance is generated when the finger touches the capacitive type touch sensor. The sensing circuit can sense a touch position and a touch area by measuring a change in capacitance (or charge) caused by a contact object in a capacitive type touch sensor to which a touch drive signal is applied.

The mutual capacitive type uses the mutual capacitance formed between the Tx lines to which the touch driving signal is applied and the Rx lines that cross the Tx lines with the dielectric layer (or insulating layer) therebetween as a touch sensor. A touch driving signal is applied to the Tx lines. The sensing circuit can sense the touch position and the touch area by receiving the capacitance change (or charge) change amount of the touch sensor which changes due to the touch object through the Rx lines. The mutual capacitive type can more accurately determine the multi-touch input than the self-capacitance type.

4 is a block diagram schematically showing a display apparatus according to the present invention.

Referring to FIG. 4, the display device of the present invention includes a touch sensing device. The touch sensing device senses a touch input using touch sensors built in the display panel 100. The touch sensors may be implemented as a capacitive sensor type as shown in Figs. 5 and 6 or a capacitive sensor type as shown in Figs.

In the liquid crystal display device, a liquid crystal layer is formed between two substrates in the display panel 100. Fig. The liquid crystal molecules of the liquid crystal layer are driven by an electric field generated by a potential difference between a data voltage applied to the pixel electrode and a common voltage (Vcom) applied to the common electrode. The pixel array of the display panel 100 includes pixels defined by data lines (S1 to Sm, m is a positive integer of 2 or more) and gate lines (G1 to Gn, n is a positive integer of 2 or more) (L1 to Li) connected to the touch sensors, and sensor lines (L1 to Li, i being a positive integer greater than 0 and less than m) connected to the touch sensors, Device (not shown in Fig. 4), and the like.

The lengths of the sensor lines L1 to Li are equal to each other in the pixel array (or screen). The common voltage Vcom is supplied to the sensor electrodes of the touch sensors through both ends of the sensor lines L1 to Li during the display driving period Td.

Each of the pixels includes a pixel TFT (Thin Film Transistor) formed at the intersections of the data lines S1 to Sm and the gate lines G1 to Gn, a pixel electrode supplied with the data voltage through the pixel TFT, And a storage capacitor Cst connected to the pixel electrode to maintain the voltage of the liquid crystal cell. The common electrode is separated into a plurality of touch sensors during the touch sensor driving period.

A black matrix, a color filter, and the like may be formed on the upper substrate of the display panel 100. The lower substrate of the display panel 100 may be implemented as a COT (Color Filter On TFT) structure. In this case, the color filter may be formed on the lower substrate of the display panel 100. [ On the upper substrate and the lower substrate of the display panel 100, a polarizing plate is attached and an alignment film for forming a pre-tilt angle of the liquid crystal is formed on the inner surface in contact with the liquid crystal. A column spacer for maintaining a cell gap of the liquid crystal layer is formed between the upper substrate and the lower substrate of the display panel 100.

A backlight unit may be disposed under the rear surface of the display panel 100. The backlight unit is implemented as an edge type or direct type backlight unit to irradiate the display panel 100 with light. The display panel 100 may be realized in any known liquid crystal mode such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode. In a self-luminous display device such as an organic light emitting diode display device, a backlight unit is not required.

The display device of the present invention further includes a display driving circuit (12, 14, 20) for writing data of an input image to pixels, a sensing circuit (30) for driving touch sensors, and a power source do.

The display driving circuits 12, 14, and 20 and the sensing circuit 30 are synchronized with each other in response to the synchronization signal Tsync. The display driving period Td and the touch sensor driving period Tt are time-divided as shown in FIG.

The display driver circuits 12, 14, and 20 write data to the pixels during the display driving period (FIG. 2, Td). The pixels hold the data voltage charged in the display driving period Td since the pixel TFT is in the off state during the touch sensor driving period (Fig. 2, Tt). The display driving circuit is connected to the sensor lines L1 to Li in order to minimize the parasitic capacitance between the touch sensors and the signal lines S1 to Sm and G1 to Gn connected to the pixels during the touch sensor driving period Tt. An AC signal having the same phase as the touch driving signal Tdrv applied to the touch sensors can be supplied to the signal lines S1 to Sm and G1 to Gn. The signal wiring connected to the pixels is a signal wiring for writing data to the pixels, and includes a data line (S1 to Sm) for supplying a data voltage to the pixels, a gate pulse And a gate line G1 to Gm to which a scan pulse is supplied.

The display driving circuits 12, 14, and 20 include a data driving circuit 12, a gate driving circuit 14, and a timing controller 20. The data driving circuit 12 converts the digital video data RGB of the input image received from the timing controller 20 during the display driving period Td into an analog positive / negative gamma compensation voltage to output a data voltage. The data voltage output from the data driving circuit 12 is supplied to the data lines S1 to Sm. The data driving circuit 12 applies an AC signal having the same phase as the touch driving signal Tdrv applied to the touch sensors to the data lines S1 to Sm during the touch sensor driving period Tt, Thereby minimizing the parasitic capacitance between them. This is because the voltage across both ends of the parasitic capacitance changes simultaneously and the smaller the voltage difference becomes, the smaller the amount of charge charged in the parasitic capacitance becomes. On the other hand, since one end of the touch sensors is connected to the sensor electrode and the other end is connected to the ground (GND), the touch sensors charge the charge when the touch driving signal Tdrv is applied.

The gate driving circuit 14 sequentially supplies a gate pulse (or a scan pulse) synchronized with the data voltage to the gate lines G1 to Gn during the display driving period Td to sequentially supply the data voltages to the display panel 100 ) Is selected. The gate pulse swings between the gate high voltage (VGH) and the gate low voltage (VGL). The gate pulse is applied to the gate of the pixel TFTs through the gate lines G1 to Gn. The gate high voltage VGL is set to a voltage higher than the threshold voltage of the pixel TFT to turn on the pixel TFT. The gate-low voltage VGL is lower than the threshold voltage of the pixel TFT. The gate driving circuit 14 applies an AC signal having the same phase as the touch driving signal Tdrv applied to the touch sensors during the touch sensor driving period Tt to the gate lines G1 to Gn, Thereby minimizing the parasitic capacitance between them. The voltage of the AC signal applied to the gate lines G1 to Gn during the touch sensor driving period Tt is lower than the gate high voltage VGH as shown in Figs. 12 and 13 so that the data written to the pixels do not change, Lt; / RTI >

The timing controller 20 inputs a timing signal such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a main clock MCLK input from the host system 40 And synchronizes the operation timings of the data driving circuit 12 and the gate driving circuit 14 with each other. The scan timing control signal includes a gate start pulse (GSP), a gate shift clock, a gate output enable signal (GOE), and the like. The data timing control signal includes a source sampling clock (SSC), a polarity control signal (Polarity), a source output enable signal (SOE), and the like.

The host system 40 may be implemented in any one of a television system, a set-top box, a navigation system, a DVD player, a Blu-ray player, a personal computer (PC), a home theater system, and a phone system. The host system 40 includes a system on chip (SoC) with a built-in scaler to convert the digital video data of the input image into a format suitable for the resolution of the display panel 100. The host system 40 transmits the timing signals Vsync, Hsync, DE, and MCLK to the timing controller 20 together with the digital video data RGB of the input image. The host system 40 also executes an application program associated with coordinate information XY of the touch input input from the sensing circuit 30. [

The timing controller 20 or the host system 40 may generate a synchronization signal Tsync for synchronizing the display driving circuit 12, 14, 20 and the sensing circuit 30. [

The common voltage Vcom is applied to the pixels through the touch sensors during the display driving period Td. The touch sensors are short-circuited to each other through the switching element T1, the feeding line D1, the feeding control line D2 and the sensor lines L1 to L4 as shown in FIG. 5 during the display driving period Td. do. With the touch sensors thus short-circuited, the common voltage Vcom is simultaneously supplied in both directions of the sensor lines L1 to L4.

The sensing circuit 30 compares the capacitance change of the touch sensors with the predetermined threshold value during the touch sensor driving period Tt and determines the capacitance change larger than the threshold value as the touch input to sense the touch input position and area. The sensing circuit 30 calculates coordinate information XY of the touch input and transmits it to the host system 40. [

The data driving circuit 12 and the sensing circuit 30 may be integrated in one integrated circuit (IC) as shown in FIGS. 5 and 11 and bonded on a substrate of the display panel by a COG (chip on glass) process.

The power supply unit 50 supplies the common voltage Vcom to one end of the sensor lines L1 to Li during the display driving period Td. The power supply unit 50 generates voltages necessary for the feed line D1 and the feed control line D2 as shown in FIG. 5 for double feeding the common voltage Vcom. The power supply unit 50 generates an AC signal having the same phase as the touch driving signal Tdrv during the touch sensor driving period Tt.

5 and 6 are views illustrating capacitive touch sensors according to an embodiment of the present invention. 5 and 6, reference numeral 11 denotes a pixel electrode of a pixel, and reference numeral 101 denotes a substrate of the display panel 100. Reference numeral 102 denotes a pixel array in which an input image is displayed. A portion outside the pixel array 102 in the display panel 100 is a bezel that is a non-display region.

Referring to FIGS. 5 and 6, the common electrode COM is divided into a plurality of sensor electrodes C1 to C4. The sensor lines L1 to L4 are connected to the sensor electrodes C1 to C4 of the touch sensors at a ratio of 1: 1. Each of the capacitive-type touch sensors includes a capacitance connected to one sensor electrode.

Each of the sensor electrodes C1 to C4 is patterned to a size larger than a pixel and connected to a plurality of pixels. Each of the sensor electrodes C1 to C4 may be formed of a transparent conductive material, for example, ITO (Indium Tin Oxide). The sensor lines L1 to L4 may be formed of a metal having a low resistance metal, for example, Cu, AlNd, Mo, Ti, or the like. The sensor electrodes C1 to C4 are common electrodes for supplying the common voltage Vcom to the pixels while being connected to each other during the display driving period Td. The sensor electrodes C1 to C4 are separated from each other during the touch sensor driving period Tt. Accordingly, the capacitive-type touch sensors are independently driven and separated from each other during the touch sensor driving period Tt.

The display device of the present invention includes a double feeding means for connecting the sensor electrodes C1 to C4 during the display driving period Td and supplying the common voltage Vcom to the sensor electrodes C1 to C4. means. The double power supply unit applies a common voltage at both ends of the sensor lines (L1 to L4) to reduce the delay of the common voltage applied to the sensor electrodes (C1 to C4), thereby making the common voltage of the pixels uniform throughout the screen.

The double feeding means includes a first feeding portion for applying a common voltage Vcom to one end of the sensor lines L1 to L4 during the display driving period Td and a second feeding portion for applying the common voltage Vcom to one end of the sensor lines L1 to L4 during the display driving period Td, And a second power feeder for connecting the sensor lines L1 to L4 to each other and supplying the common voltage Vcom to the other end of the sensor lines L1 to L4. The touch sensors are short-circuited because the sensor lines L1 to L4 are connected through the feed line D1 during the display driving period Td.

The first feeder supplies a touch driving signal to the touch sensors through the sensor lines (L1 to L4) during the touch sensor driving period (Tt). The second feed unit separates the sensor lines during the touch sensor driving period (Tt) so that the touch sensors are independently driven.

The first feeder and the second feeder are located on opposite sides of the sensor lines L1 through L4. The first feeder may be an IC connected to the lower ends of the sensor lines L1 to L4 in FIG. 5, and the second feeder may be connected to the upper end of the sensor lines L1 to L4, but is not limited thereto. For example, when the sensor lines L1 to L4 are formed along the transverse direction, the first feeder and the second feeder are disposed on the left side of the display panel 100 with their sensor lines L1 to L4 interposed therebetween. May be disposed on the right side.

The second feed unit includes a TFT T1 connected to the sensor lines L1 through L4, a feed line D1 connected to the TFT T1, and a feed control line D2. The TFT (T1) is formed simultaneously with the pixel TFT with the same structure and size as the pixel TFT. The TFT T1 has a gate connected to the feed control line D2, a drain connected to the feed line D1, and a source connected to the sensor line. Therefore, the TFT T1 selectively connects the feed line D1 and the sensor line in response to the voltage of the feed control line D2.

The feed line D1 and the feed control line D2 are low resistance metal lines formed along the bezel area outside the pixel array 102. [ The power supply unit 50 supplies the common voltage Vcom to the power supply line D1 during the display driving period Td and supplies the gate high voltage VGH through the power supply control line D2 to turn on the TFT T1 - Turn-on. The TFT T1 supplies the common voltage Vcom from the feeder line D1 to the sensor lines (not shown) in response to the gate high voltage VGH applied through the feed control line D2 during the display drive period Td L1 to L4.

The TFT T1 maintains the off state during the touch sensor driving period Tt. An AC signal having the same phase as the touch driving signal Tdrv may be applied to the gate and drain of the TFT in order to minimize the parasitic capacitance with the sensor lines L1 to L4. During the touch sensor driving period Tt, the feed line D1 and the feed control line D2 can be controlled as shown in FIGS. 7 to 9. FIG. This will be described later with reference to FIGS. 7 to 9. FIG.

The feed line D1 and the feed control line D2 may be connected to the power source unit 50 through a flexible printed circuit (FPC).

7 to 9 are waveform diagrams showing a pixel driving signal and a touch driving signal applied to the display device of the present invention. 7 to 9, 'Ten' is the voltage of the feed control line D2 and 'Vcom_FPC' is the voltage of the feed line D1.

Referring to FIG. 7, the display driving period Td and the touch sensor driving period Tt are time-divided.

The pixels write data of the input image during the display driving period Td. During the display driving period Td, a data voltage of the input image is supplied to the data lines S1 and S2, and a gate pulse synchronized with the data voltage is sequentially applied to the scan lines G1 and G2. The common voltage Vcom is supplied to the sensor electrodes C1 to C4 connected to each other through both ends of the sensor lines L1 to L4 during the display driving period Td. The gate high voltage VGH higher than the threshold voltage of the TFT T1 is supplied to the power supply control line D2 and the common voltage Vcom is supplied to the power supply line D1 during the display driving period Td. Therefore, the common voltage Vcom is supplied to both ends of the sensor lines L1 to L4 through the IC and the TFT T1. Since the voltage drop of the sensor electrodes C1 to C4 can be prevented when the common voltage Vcom is applied to the sensor electrodes C1 to C4 through both ends of the sensor lines L1 to L4, So that the image quality can be improved.

The data voltage charged in the pixels is maintained during the touch sensor driving period Tt. This is because the pixel TFT and the TFT T1 of the second feeder remain in the off state during the touch sensor driving period Tt. The power supply unit 50 generates a voltage of the touch driving signal Tdrv to be supplied to the sensor electrodes C1 to C4 during the touch sensor driving period Tt. The output terminals of the power supply unit 50 are separated from the feed line D1 and the feed control line D2 during the touch sensor drive period Tt. Therefore, the feed line D1 and the feed control line D2 can maintain a high impedance (Hi-Z) state in which no voltage is applied during the touch sensor driving period Tt. The TFT T1 maintains the off state during the touch sensor driving period Tt because the feed line D1 and the feed control line D2 maintain high impedance (Hi-Z).

The power supply unit 50 generates an AC signal having the same phase as the touch driving signal Tdrv in order to minimize the parasitic capacitance between the sensor lines L1 to L4 and the signal lines S1, S2, G2 and G2 connected to the pixels, Occurs during the touch sensor driving period Tt. In order to minimize the parasitic capacitance, the voltage of the AC signal may be set equal to the touch driving signal Tdrv.

Referring to FIG. 8, the pixel driving method and the touch sensor driving method during the display driving period Td are substantially the same as those in the embodiment of FIG. 7, and thus a detailed description thereof will be omitted.

The data voltage charged in the pixels is maintained during the touch sensor driving period Tt. This is because the pixel TFT and the TFT T1 of the second feeder remain in the off state during the touch sensor driving period Tt. The feed line D1 maintains a high impedance state during the touch sensor driving period Tt. The voltage of the power supply control line D2 maintains the gate low voltage VGL lower than the threshold voltage of the TFT T1 during the touch sensor driving period Tt.

The power supply unit 50 generates a voltage of the touch driving signal Tdrv to be supplied to the sensor electrodes C1 to C4 during the touch sensor driving period Tt. The power supply unit 50 generates an AC signal having the same phase as the touch driving signal Tdrv in order to minimize the parasitic capacitance between the sensor lines L1 to L4 and the signal lines S1, S2, G2 and G2 connected to the pixels, Occurs during the touch sensor driving period Tt. In order to minimize the parasitic capacitance, the voltage of the AC signal may be set equal to the touch driving signal Tdrv.

Referring to FIG. 9, the pixel driving method and the touch sensor driving method during the display driving period Td are substantially the same as the embodiment of FIG. 7, and a detailed description thereof will be omitted.

The data voltage charged in the pixels is maintained during the touch sensor driving period Tt. This is because the pixel TFT and the TFT T1 of the second feeder remain in the off state during the touch sensor driving period Tt.

The power supply unit 50 generates a voltage of the touch driving signal Tdrv to be supplied to the sensor electrodes C1 to C4 during the touch sensor driving period Tt. The power supply unit 50 includes parasitic capacitances between the sensor lines L1 to L4 and the signal lines S1 to S2 connected to the pixels and the parasitic capacitance between the sensor lines L1 to L4 and the feed line D1. And the parasitic capacitance between the sensor lines L1 to L4 and the parasitic capacitance between the power supply control line D2 and the touch driving signal Tdrv. In order to minimize the parasitic capacitance, the voltage of the AC signal may be set equal to the touch driving signal Tdrv. This AC signal is supplied to the sensor lines L1 to L4 during the touch sensor driving period Tt, the signal lines S1, S2, G2 and G2 connected to the pixels, the feeding line D1 and the feeding control line D2 . The AC drive signal generated in the same phase of the touch drive signal Tdrv and the touch drive signal Tdrv is smaller than the threshold voltage of the TFT T1. Therefore, the TFT T1 maintains the off state during the touch sensor driving period Tt.

10 is a waveform diagram showing various examples of the touch driving signal Tdrv.

The touch driving signal Tdrv may be generated with various waveforms and voltages in consideration of the size, resolution, and RC delay of the display panel. For example, when the RC delay is large, it is preferable to set the voltage of the touch driving signal Tdrv higher in consideration of the voltage drop. In FIG. 10, M1 to M3 (M1> M2> M3> M4) are voltages of the touch driving signal Tdrv. The touch-driving signal Tdrv may be generated in a multi-step waveform as shown in Fig. 10 (C). M1 is a potential for charging the charge of the touch sensor within a short period of time, and M3 is a potential for discharging the residual charge of the touch sensor quickly. The touch-driving signal Tdrv shown in FIG. 10 (C) is a multi-step (multi-step) signal proposed in Korean patent application 10-2012-0130538 (Nov. 16, 2012), US patent application 14 / 079,798 multi step waveforms. An AC signal generated in phase with the touch driving signal Tdrv may be generated in various waveforms as shown in FIG. The AC signal may be generated in the same phase, the same voltage, and the same waveform as the touch driving signal Tdrv as shown in Figs. 7 to 9, Fig. 12, and Fig.

11 is a circuit diagram showing a driving circuit of a display device according to an embodiment of the present invention in detail. FIGS. 12 and 13 are waveform diagrams showing a pixel driving signal and a touch driving signal output from the driving circuit shown in FIG. 11, 'Clc' is a liquid crystal cell and 'T3' is a pixel TFT.

11 to 13, the power supply unit 50 includes a power supply unit 50 and a power supply unit 50. The power supply unit 50 includes common voltages Vcom1 and Vcom2, a logic power supply voltage Vcc, gate high voltages VGH1 and VGH2, gate low voltages VGL1 and VGL2, (M1 to M4). The logic supply voltage Vcc is the gate drive circuit 14 and the driving power source of the IC.

The first common voltage Vcom1 is applied to one end of the sensor lines L1 to L4 through the first feeders 31 and 32 in the IC. The second common voltage Vcom2 is applied to the other end of the sensor lines L1 to L4 through the second feeders D1, D2, and T1. The second common voltage Vcom2 is greater than the first common voltage Vcom1 when the load connected to the second feeders D1, D2 and T1 is greater than the load connected to the first feeders 31 and 32. [ It is preferable to set it larger. If the load difference is small, the first and second common voltages Vcom1 and Vcom2 can be set to the same potential.

The first gate high voltage VGH1 and the first gate low voltage VGL1 are supplied to the gate lines G1 and G2 through the gate driving circuit 14. [ The kickback voltage of the liquid crystal cell Clc is generated due to the parasitic capacitance of the liquid crystal cell and causes a flicker. As shown in FIG. 12, when the first gate high voltage VGH1 is lowered at the falling edge of the gate pulse, the kickback voltage can be lowered, thereby improving the flicker. The gate driving circuit 14 supplies gate lines G1 and G2 with gate pulses swinging between the first gate high voltage VGH1 and the first gate low voltage VGL1 during the display driving period Td. The gate driving circuit 14 supplies the AC signals to the gate lines G1 and G2 in synchronization with the touch driving signal Tdrv during the touch sensor driving period Tt.

The second gate high voltage VGH2 and the second gate low voltage VGL2 are supplied to the power supply control line D2. The second gate high voltage VGH2 is set to be larger than the first gate high voltage VGH1 when the load connected to the second feed portions D1, D2 and T1 is larger than the load connected to the gate drive circuit 14 . When the load connected to the second power feeders D1, D2, and T1 is greater than the load connected to the gate driving circuit 14, the second gate low voltage VGL2 is higher than the first gate low voltage VGL1 It is desirable to set it low. If the load difference is small, the first and second gate high voltages VGH1 and VGH2 may be set to the same potential and the first and second gate low voltages VGL1 and VGL2 may be set to the same potential .

The AC signal voltages M1 to M4 are the voltages of the AC drive signal synchronized with the touch drive signal Tdrv.

The power supply unit 50 may be divided into a first power supply unit 50A and a second power supply unit 50B. The first power supply unit 50A supplies a voltage necessary for driving the IC and the gate drive circuit 14. [ The second power supply unit 50B supplies a voltage necessary for driving the second power feeder 62. [

The first power supply unit 50A includes a plurality of multiplexers 51-54. The first multiplexer 51 selects the first gate low voltage VGL1 and the AC signal voltages M1 to M4 output from the second multiplexer 52 in response to the first selection signal and supplies the selected signal to the gate driving circuit 14, . In response to the second selection signal, the second multiplexer 52 selects and outputs the AC signal voltages M1 to M4 according to the waveform of the previously set AC signal. The first gate high voltage VGH1 is supplied directly to the gate drive circuit 14. [

The third multiplexer 53 supplies the AC signal voltages M1 to M4 to the second multiplexer 32 of the first feeders 31 and 32 during the touch sensor driving period Tt in response to the third select signal . The fourth multiplexer 54 supplies the AC signal voltages M1 to M4 to the multiplexer 13 connected to the data lines S1 and S2 during the touch sensor driving period Tt in response to the fourth selection signal.

The IC includes a data driving circuit 12, a sensing circuit 30, first feeders 31 and 32, a multiplexer 13, and the like.

The first multiplexer 31 of the first feeders 31 and 32 includes an output terminal connected to the sensor lines L1 to L4 and an input terminal connected to the second multiplexer 32 and the sensing circuit 30. The first multiplexer 31 supplies the first common voltage Vcom1 input through the second multiplexer 32 to the sensor lines L1 to L4 in response to the fifth selection signal during the display driving period Td . The first multiplexer 31 supplies the AC signal voltages M1 to M4 inputted through the second multiplexer 32 to the sensor lines L1 to L4 during the touch sensor driving period Tt and outputs the AC signal voltages M1 to M4 to the sensor lines L1 to L4 are connected to the sensing circuit 30. The sensing circuit 30 senses a capacitance change based on a result of counting signal changes of the sensor lines L1 to L4 during the touch sensor driving period Tt.

The second multiplexer 32 includes an output connected to the first multiplexer 31 and an input connected to the first power supply 50A. The second multiplexer 32 supplies the first common voltage Vcom1 to the first multiplexer 31 during the display driving period Td in response to the sixth selection signal, And supplies the voltages (M1 to M4) to the first multiplexer (31).

The multiplexer 13 includes an output stage connected to the data lines S1 and S2 and an input stage connected to the data drive circuit 12 and the first voltage source 50A. The multiplexer 13 supplies the data voltage of the input image to the data lines S1 and S2 during the display driving period Td and then supplies the alternating signal voltage Vdd during the touch sensor driving period Tt in response to the seventh selection signal. M1 to M4 to the data lines S1 and S2.

The second power supply unit 50B includes first through fourth multiplexers 55-58.

The first multiplexer 55 includes an output terminal connected to the feed control line D2 and an input terminal connected to the second multiplexer 57. [ The first multiplexer 55 supplies the second gate high voltage VGH2 to the feed control line D2 during the display drive period Td in response to the eighth select signal. The first multiplexer 55 selects the high impedance terminal Hi-Z and the second multiplexer 57 during the touch sensor driving period Tt in response to the eighth selection signal to implement the driving method of Figs. To the power supply control line D2 or to supply the second gate-low voltage VGL2 to the power supply control line D2.

The second multiplexer 57 includes an output terminal connected to the first multiplexer 55 and an input terminal to which the AC signal voltages M1 to M4 are supplied. The second multiplexer 57 supplies the AC signal voltages M1 to M4 during the touch sensor driving period Tt in response to the ninth selection signal.

The third multiplexer 56 includes an output connected to the feed line D1 and an input connected to the fourth multiplexer 58. [ The third multiplexer 56 supplies the second common voltage Vcom2 to the feed line D1 during the display driving period Td in response to the tenth selection signal. The third multiplexer 56 is connected to the high impedance terminal Hi-Z and the fourth multiplexer 58 during the touch sensor driving period Tt in response to the tenth selection signal to implement the driving method of Figs. To the power supply control line D2.

The fourth multiplexer 58 includes an output connected to the third multiplexer 56 and an input to which the AC signal voltages M1 to M4 are supplied. The fourth multiplexer 57 supplies the AC signal voltages M1 to M4 during the touch sensor driving period Tt in response to the eleventh selection signal.

The microcontroller unit (MCU) of the timing controller 20 or the sensing circuit 30 may generate selection signals for controlling the multiplexers 51 to 58, 13, 31 and 32.

FIG. 14 is an equivalent circuit diagram showing the mutual capacitance type touch sensors according to the embodiment of the present invention. 15 to 17 are views showing examples in which double power feeding means are connected to the touch sensors as shown in FIG.

14 to 17, the mutual capacitance Cm of the touch sensors is formed between the Tx lines Tx1 to Tx6 and the Rx lines Rx1 to R7. The Tx lines Tx1 to Tx6 are orthogonal to the Rx lines Rx1 to R7.

The Tx lines Tx1 to Tx6 and the Rx lines Rx1 to R7 are divided from the common electrode COM to which the common voltage Vcom is supplied. Each of the Tx lines Tx1 to Tx6 is formed by a method of connecting neighboring sensor electrodes along the lateral direction (x-axis direction). The Rx lines Rx1 to R7 are elongated along the longitudinal direction (y-axis direction) so as to be orthogonal to the Tx lines Tx1 to Tx6. The sensor electrodes of the neighboring Tx line along the transverse direction are connected through routing lines 104 formed in a bezel area outside the pixel array 102 as shown in Figs. 15 and 17, or connected to the pixel array 102 via a bridge pattern 103. In this embodiment, The bridge pattern penetrates the insulating layer and connects the sensor electrodes of the separated Tx line via the Rx lines Rx1 to R7.

An AC signal having the same phase as the touch driving signal Tdrv is applied to the signal lines S1, S2, G1 and G2 connected to the pixels and the Rx line Rx during the touch sensor driving period Tt, Can be minimized. Also, during the touch sensor driving period Tt, an AC signal having the same phase as the touch driving signal Tdrv may be applied to the feeding line D1 and the feeding control line D2.

To charge the mutual capacitance Cm, a potential difference must exist between the Tx line and the Rx line. Therefore, the AC signal applied to the Rx line must have the same phase and lower voltage as the touch driving signal Tdrv.

The double power supply means supplies the common voltage Vcom to both ends of the Tx lines Tx1 to Tx6 and the Rx lines Rx1 to R7 during the display driving period Td and then applies the common voltage Vcom to the both ends of the Tx lines And supplies the touch driving signal Tdrv to the lines Tx1 to Tx6. The sensing circuit 30 measures the amount of charge change received through the Rx lines Rx1 to Rx7 in synchronization with the touch drive signal Tdrv and compares the amount of charge change with a predetermined threshold value to determine a charge change amount As a touch input, and calculates coordinates.

 The power supply unit 50 generates necessary voltages for the feed line D1 and the feed control line D2 for double feeding of the common voltage Vcom. The power supply unit 50 generates power such as a gate high voltage VGH, a gate low voltage VGL, a gamma reference voltage, a logic power supply voltage Vcc for driving the driving circuits 20, 12, 14, do. The analog positive / negative gamma compensation voltage is divided from the gamma reference voltage. The power supply unit 50 generates an AC signal voltage having the same phase as the touch driving signal Tdrv during the touch sensor driving period Tt.

The double power feeding means includes a first feeder 61 for applying a common voltage Vcom to one end of the sensor lines L1 to L4 and a second feeder 61 for feeding the sensor lines L1 to L4 to each other via the feed line D1. And a second power feeder 62 for supplying a common voltage Vcom to the other end of the sensor lines L1 to L4. The Tx lines and the Rx lines are short-circuited because the sensor lines L1 to L4 are connected through the feed line D1 during the display driving period Td.

The first feeder 61 supplies the touch driving signal Tdrv to the Tx lines through the sensor lines L1 to L4 during the touch sensor driving period Tt. The second feed unit separates the sensor lines during the touch sensor driving period (Tt) to separate the Tx lines and the Rx lines.

The first feeder 61 and the second feeder 62 are located on opposite sides of the sensor lines L1 through L4. The sensor lines L1 to L4 are connected to the sensor electrodes of the Tx lines. The second feeder 62 includes a TFT T1 connected to the sensor lines L1 through L4, a TFT T2 connected to the Rx line, a feed line D1 connected to the TFTs T1 and T2, And lines D2, D2a, and D2b.

The TFTs T1 and T2 are formed simultaneously with the pixel TFT with the same structure and size as the pixel TFT. The first TFT T1 has a gate connected to the feed control lines D2 and D2a, a drain connected to the feed line D1, and a source connected to the sensor line. Therefore, the TFT T1 selectively connects the feed line D1 and the sensor line in response to the voltage of the feed control line D2.

The second TFT T2 has a gate connected to the feed control lines D2 and D2b, a drain connected to the feed line D1, and a source connected to the Rx line. Therefore, the second TFT T2 selectively connects the feed line D1 and the Rx line in response to the voltage of the feed control lines D2 and D2b. It is possible to separately control the first TFT (T1) and the second TFT (T2) in consideration of the difference between the load connected to the Tx line and the load connected to the Rx line as shown in FIG. 17, so that the power supply time and the supply voltage can be controlled differently.

The TFTs T1 and T2 remain off during the touch sensor driving period Tt. The touch driving signal Tdrv (Tdrv) is applied to the gate and drain of the TFTs T1 and T2 through the feeding line D1 and the feeding control lines D2 and D2a and D2b in order to minimize the parasitic capacitance between the TFTs T1 and T2 and the sensor lines L1 to L4. The AC signal having the same phase as the AC signal can be applied.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the specification, but should be defined by the claims.

100: display panel 12: data driving circuit
14: gate drive circuit 31, 32:
62: Second class all parts

Claims (9)

Signal wires connected to the pixels;
Sensor lines connected to the touch sensors;
A first power feeder supplying a common voltage to one end of the sensor lines during a display driving period and supplying a touch driving signal to one end of the sensor lines during a touch sensor driving period; And
And a second power feeder for disconnecting the sensor lines during the touch sensor driving period while connecting the sensor lines during the display driving period to short-circuit the touch sensors and supply the common voltage at the other end of the sensor lines and,
Each of the sensor lines extending long in the same direction between one end and the other end of each of the sensor lines,
Wherein the first feeder and the second feeder supply the common voltage to both ends of the same sensor line while the sensor lines are connected to each other. The method according to claim 1,
The second feed portion may include:
And a TFT having a source connected to the sensor lines, a drain connected to a connected feed line, and a gate connected to the feed control line,
During the display driving period, a gate high voltage higher than the threshold voltage of the TFT is supplied to the power supply control line, the common voltage is supplied to the power supply line,
Wherein the TFT is turned on in response to the gate high voltage during the display driving period to connect the sensor lines to the feed line. 3. The method of claim 2,
Wherein the feed control line and the feed line maintain a high impedance state during the touch sensor driving period. 3. The method of claim 2,
A gate low voltage lower than a threshold voltage of the TFT is supplied to the power supply control line during the touch sensor driving period,
Wherein the feed line maintains a high impedance state during the touch sensor driving period. 3. The method of claim 2,
And supplies an AC signal having the same phase as the touch driving signal to each of the feed control line and the feed line during the touch sensor driving period. 6. The method of claim 5,
And supplying a data voltage and a gate pulse for writing data of an input image to the pixels during the display driving period to the signal lines, And a display driving circuit for supplying an AC signal. The method according to claim 5 or 6,
Wherein the AC signals are generated with the same voltage as the touch driving signal. 3. The method of claim 2,
Wherein the feed line and the feed control line are formed along a bezel area outside the pixel array of the display panel. A method of driving a touch sensing apparatus including signal lines connected to pixels and sensor lines connected to touch sensors,
Connecting the sensor lines during a display driving period to short-circuit the touch sensors, and supplying a common voltage to the sensor lines through one end and the other end of the sensor lines; And
Separating the sensor lines during a touch sensor driving period and supplying a touch driving signal to one end of the sensor lines,
Each of the sensor lines extending long in the same direction between one end and the other end of each of the sensor lines,
Wherein the common voltage is supplied to both ends of the same sensor line while the sensor lines are connected to each other.

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