KR102429413B1 - Touch display device, display panel, common electrolde driving circuit and driving method - Google Patents

Abstract

Embodiments of the present invention relate to a touch display device, a display panel, a common electrode driving circuit and a driving method, and more particularly, a common voltage applied to a common electrode used as a touch electrode by configuring a common voltage compensation circuit, etc. The present invention relates to a touch display device, a display panel, a common electrode driving circuit, and a driving method that can be stabilized without being unstable by noise such as ripple, and through which display driving and touch driving can be performed normally and stably .

Description

Touch display device, display panel, common electrode driving circuit and driving method

The present invention relates to a touch display device, a display panel, a common electrode driving circuit, and a driving method.

As the information society develops, the demand for a touch display device for displaying an image is increasing in various forms, and in recent years, various display devices such as a liquid crystal display device, a plasma display device, an organic light emitting display device, etc. are utilized.

Among these display devices, there is a touch display device that provides a touch-based input method that allows a user to easily and intuitively and conveniently input information or a command by breaking away from a conventional input method such as a button, a keyboard, and a mouse.

In the conventional touch display device, during the touch driving period, the touch electrode to be sensed is affected by the surrounding electrodes or wires, and noise such as ripple may be generated. Accordingly, there is often a problem in that the touch sensitivity is greatly reduced.

In particular, when a common electrode used for driving a display is used as a touch electrode, the above-described problem may be more severe, and a problem that the display driving may not be performed normally may also occur.

Against this background, an object of the embodiments of the present invention is to remove or reduce noise, such as ripple, generated from a common electrode that is also used as a touch electrode, and thus a touch display device and a display panel capable of normally performing display driving and touch driving , to provide a common electrode driving circuit and a driving method.

Another object of the embodiments of the present invention is to remove or reduce noise, such as ripple, generated in a common electrode commonly used for display driving and touch driving, so that the display driving and the touch driving can be time-divided and normally performed by touch. To provide a display device, a display panel, a common electrode driving circuit, and a driving method.

Another object of the embodiments of the present invention is to remove or reduce noise, such as ripple, generated from a common electrode commonly used for display driving and touch driving, so that display driving and touch driving can be performed normally at the same time. To provide an apparatus, a display panel, a common electrode driving circuit, and a driving method.

In one aspect, embodiments of the present invention provide a display panel in which a plurality of data lines and a plurality of gate lines are disposed, a plurality of common electrodes are disposed, and a plurality of signal lines electrically connected to the plurality of common electrodes are disposed. and a data driving circuit for outputting a data voltage to a data line, a gate driving circuit for outputting a gate signal to a gate line, and a common electrode driving circuit for outputting a common voltage to a common electrode. have.

In such a touch display device, the common electrode driving circuit includes a common voltage compensation circuit that receives a common voltage fed back from the display panel, inverts the polarity of the fed back common voltage and outputs the common voltage compensation circuit, and a common voltage corresponding to the output signal of the common voltage compensation circuit. It may include an output circuit for outputting.

The common voltage compensation circuit may include a feedback node to which the common voltage fed back from the display panel is applied.

The common voltage compensation circuit includes a first input terminal to which a first input voltage is applied, a second input terminal electrically connected to the feedback node and to which a second input voltage corresponding to the fed back common voltage is applied, and an output for outputting an output voltage It may include an inverting amplifier having a stage.

For each common electrode column, a feedback line electrically connecting a specific common electrode and a feedback node of the common voltage compensation circuit may be disposed on the display panel.

The specific common electrode may be a common electrode located farthest from the common electrode driving circuit in each common electrode column.

A dummy electrode may be disposed in an outer region of the display panel and corresponding to each common electrode column, and a feedback line may be disposed on the display panel to electrically connect the dummy electrode and the feedback node of the common voltage compensation circuit for each common electrode column. .

The dummy electrode may be located outside the common electrode located farthest from the common electrode driving circuit in each common electrode column.

In another aspect, embodiments of the present invention provide a plurality of data lines arranged in a first direction, a plurality of gate lines arranged in a second direction, a plurality of common electrodes arranged in a row, and a plurality of common electrodes. It is possible to provide a display panel including a plurality of signal lines respectively electrically connected to the .

Such a display panel may include one or more feedback lines electrically connected to one or more specific common electrodes among the plurality of common electrodes or electrically connected to one or more other electrodes disposed outside the plurality of common electrodes.

After the feedback signal is output from the feedback line, the signal supplied to the signal line may have a polarity reversed from the polarity of the feedback signal.

The feedback line may be longer than the longest signal line among the plurality of signal lines.

The specific common electrode may be a common electrode located farthest from the pad area among the plurality of common electrodes.

The other electrode may be located outside the common electrode located farthest from the pad area among the plurality of common electrodes.

In another aspect, embodiments of the present invention may include a common electrode driving circuit for driving a plurality of common electrodes disposed on a display panel.

The common electrode driving circuit includes a first input terminal (+) to which a first input voltage is applied, a second input terminal (-) to which a second input voltage corresponding to the common voltage fed back from the display panel is applied, and an output voltage It may include an inverting amplifier having an output stage for outputting , and an output circuit for outputting a common voltage corresponding to the output voltage.

The output circuit may be in the form of a signal wiring, and may further include components such as an amplifier or a preamplifier.

In another aspect, embodiments of the present invention include the steps of supplying a common voltage to a display panel, receiving feedback of the common voltage from the display panel, inverting the polarity of the fed back common voltage, and inverting the polarity. It is possible to provide a driving method including the step of supplying a common voltage to the display panel.

According to the present invention described above, a touch display device, a display panel, and a common electrode driving circuit capable of normally performing display driving and touch driving by removing or reducing noise, such as ripple, generated from a common electrode that is also used as a touch electrode. A furnace and a driving method may be provided.

According to the present invention, a touch display device and a display panel capable of normally performing display driving and touch driving by time division by removing or reducing noise such as ripple generated from a common electrode commonly used for display driving and touch driving , a common electrode driving circuit and a driving method can be provided.

According to the present invention, a touch display device, a display panel, and a common electrode capable of performing display driving and touch driving normally at the same time by removing or reducing noise such as ripple generated in a common electrode commonly used for display driving and touch driving An electrode driving circuit and a driving method can be provided.

1 and 2 are system configuration diagrams of a touch display device according to embodiments of the present invention.
3 is a diagram illustrating a display panel having a built-in touch panel in a touch display device according to embodiments of the present invention.
4 is a time division driving timing diagram of a touch display device according to embodiments of the present invention.
5 is a time-free driving timing diagram of a touch display device according to embodiments of the present invention.
6 is a diagram illustrating a ground environment of a touch display device according to embodiments of the present invention.
7 is a time-free driving timing diagram during ground modulation in a touch display device according to embodiments of the present invention.
8 is a diagram illustrating a touch driving circuit of a touch display device according to embodiments of the present invention.
9 is a diagram illustrating a touch driving operation for one common electrode column performed by a touch driving circuit of a touch display device according to embodiments of the present invention.
10 is a diagram illustrating a touch driving operation for a touch panel performed by a touch driving circuit of a touch display device according to embodiments of the present invention.
11 is a view for explaining a common voltage ripple phenomenon that occurs during touch driving of a touch display device according to embodiments of the present invention and a touch sensing failure according thereto.
12 and 13 are diagrams illustrating a common electrode driving operation when a display of a touch display device is driven according to embodiments of the present invention.
14 is a diagram for explaining a common voltage compensation principle in a common voltage compensation system of a touch display device according to embodiments of the present invention.
15 is a diagram schematically illustrating a common voltage compensation circuit CC in a common voltage compensation system of a touch display device according to embodiments of the present invention.
16 is a diagram illustrating a common voltage compensation system of a touch display device according to embodiments of the present invention.
17 is an exemplary diagram of a common voltage compensation system of a touch display device according to embodiments of the present invention.
18 is another exemplary diagram of a common voltage compensation system of a touch display device according to embodiments of the present invention.
19 is another exemplary diagram of a common voltage compensation system of a touch display device according to embodiments of the present invention.
20 is a flowchart of a driving method according to embodiments of the present invention.

Hereinafter, some embodiments of the present invention will be described in detail with reference to exemplary drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

In addition, in describing the components of the present invention, terms such as first, second, A, B, (a), (b), etc. may be used. These terms are only for distinguishing the elements from other elements, and the essence, order, order, or number of the elements are not limited by the terms. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected,” “coupled,” or “connected” through another component.

1 and 2 are system configuration diagrams of a touch display device according to embodiments of the present invention.

A touch display device according to embodiments of the present invention may perform an image display function and a touch sensing function (touch input function).

Hereinafter, configurations for the touch display device according to embodiments of the present invention to provide an image display function will be described with reference to FIG. 1 , and the touch display device according to the embodiments of the present invention provides a touch sensing function (touch input). function) will be described with reference to FIG. 2 .

Referring to FIG. 1 , a touch display device according to embodiments of the present invention may include a display panel DISP and driving circuits for driving the display panel DISP to provide an image display function.

A plurality of data lines DL and a plurality of gate lines GL are disposed on the display panel DISP, and a plurality of data lines DL and a plurality of gate lines GL defined by the plurality of data lines DL and GL are disposed. The subpixels SP of are arranged.

The driving circuits for driving the display panel DISP include a data driving circuit DDC driving the plurality of data lines DL, a gate driving circuit GDC driving the plurality of gate lines GL, and , a display controller D-CTR for controlling the data driving circuit DDC and the gate driving circuit GDC, and the like.

Pixel electrodes in each sub-pixel SP may be disposed on the display panel DISP.

A pixel voltage may be applied to the pixel electrode of each sub-pixel SP.

Also, one or more common electrodes CE to which a common voltage is applied may be disposed on the display panel DISP.

One common electrode CE is a single cylindrical electrode formed on the front surface of the display panel DISP.

The two or more common electrodes CE may be regarded as an electrode obtained by dividing one cylindrical electrode into two or more. Each of the two or more common electrodes CE may have a size greater than the size of one sub-pixel area.

In each sub-pixel SP, a corresponding electric field may be formed by the pixel voltage (which may be a data voltage) applied to the corresponding pixel electrode and the common voltage applied to the common electrode CE.

The display controller D-CTR supplies various driving control signals DCS and GCS to the data driving circuit DDC and the gate driving circuit GDC to control the data driving circuit DDC and the gate driving circuit GDC. control

The display controller (D-CTR) starts scanning according to the timing implemented in each frame, and converts the input image data input from the outside according to the data signal format used by the data driving circuit (DDC) to convert the converted image data (DATA) is output, and data operation is controlled at an appropriate time according to the scan.

The display controller D-CTR may include a timing controller used in the field of display technology, and may be a control device further including other control functions or modules.

The display controller D-CTR may be implemented as a separate component from the data driving circuit DDC, or may be integrated with the data driving circuit DDC and implemented as an integrated circuit.

The data driving circuit DDC receives image data DATA from the display controller D-CTR and supplies a data voltage to the plurality of data lines DL to drive the plurality of data lines DL. .

The data driving circuit DDC may be implemented by including at least one source driver integrated circuit.

Each source driver integrated circuit is connected to a bonding pad of the display panel DISP by a tape automated bonding (TAB) method or a chip on glass (COG) method, or the display panel It may be directly disposed on the DISP or, in some cases, may be integrated and disposed on the display panel DISP. In addition, each source driver integrated circuit SDIC may be implemented in a Chip On Film (COF) method mounted on a film connected to the display panel DISP.

The gate driving circuit GDC sequentially drives the plurality of gate lines GL by sequentially supplying a scan signal to the plurality of gate lines GL.

The gate driving circuit GDC may be implemented by including at least one gate driver integrated circuit.

Each gate driver integrated circuit is connected to a bonding pad of the display panel DISP by a tape automated bonding (TAB) method or a chip-on-glass (COG) method, or is implemented as a GIP (Gate In Panel) type. It may be directly disposed on the display panel DISP or, in some cases, may be integrated and disposed on the display panel DISP. In addition, each gate driver integrated circuit GDIC may be implemented in a chip-on-film (COF) method that is mounted on a film connected to the display panel DISP.

The gate driving circuit GDC sequentially transmits a scan signal (gate signal) of an on voltage or an off voltage to the plurality of gate lines GL under the control of the display controller D-CTR. supply

When a specific gate line is opened by the gate driving circuit GDC, the data driving circuit DDC converts the image data DATA received from the display controller D-CTR into an analog data voltage to a plurality of data lines. Supplied by DL.

The data driving circuit DDC may be located only on one side (eg, upper or lower side) of the display panel DISP. : It may be located both above and below).

The gate driving circuit GDC may be located only on one side (eg, left or right side) of the display panel DISP, and in some cases, both sides (eg, the left side or the right side) of the display panel DISP according to a driving method, a panel design method, etc. For example, it can be located on both the left and right side).

Referring to FIG. 2 , the touch display device according to the embodiments provides a touch sensing function, a touch panel TSP built into the display panel DISP, and detecting the touch panel TSP to determine whether there is a touch or not. A touch circuit TC for finding out touch coordinates may be included.

In the touch panel TSP, a plurality of common electrodes CE serving as touch electrodes (touch sensors) are disposed in a touch area (which may correspond to a display area), and are electrically connected to the plurality of common electrodes CE, respectively. A plurality of connected signal lines SL may be disposed. That is, at least one signal line SL may be connected to each of the plurality of common electrodes CE.

Each common electrode CE may be an electrode without an opening.

Alternatively, each common electrode CE may be a mesh-type electrode having a plurality of openings, or a comb-tooth-shaped electrode.

Each common electrode CE may be electrically connected to one or more signal lines SL through one or more contact holes.

The plurality of signal lines SL electrically connect the plurality of common electrodes CE to the common electrode driving circuit CDC.

The touch circuit TC may include a common electrode driving circuit CDC, a touch controller T-CTR, and the like.

The common electrode driving circuit CDC and the touch controller T-CTR may be implemented separately or may be integrated and implemented as one.

The common electrode driving circuit CDC may be configured separately from the data driving circuit DDC or may be implemented by being integrated with the data driving circuit DDC.

The common electrode driving circuit CDC may generate and output sensing data by driving the touch panel TSP.

For example, the common electrode driving circuit CDC supplies a driving signal to all or a part of the plurality of common electrodes CE disposed on the touch panel TSP, and detects a sensing signal from at least one common electrode CE. to generate and output the sensed data.

The common electrode driving circuit CDC may supply a driving signal (touch driving signal) to one or more common electrodes CE through one or more signal lines SL and detect a sensing signal (touch sensing signal).

The touch controller T-CTR may acquire touch presence and/or touch coordinates by using the sensed data output from the common electrode driving circuit CDC.

The touch display device may detect a touch based on mutual-capacitance or may detect a touch based on self-capacitance.

When a touch is sensed based on mutual-capacitance, the plurality of common electrodes CE disposed on the touch panel TSP may be disposed in a matrix form. In this case, each common electrode CE may have a bar shape.

Alternatively, when sensing a touch based on mutual-capacitance, the plurality of common electrodes CE disposed on the touch panel TSP may form row-direction touch electrode lines and column-direction touch electrode lines. In this case, each common electrode CE may have a diamond shape, a rectangular shape, or a square shape.

The common electrode driving circuit CDC supplies driving signals to the common electrode CE or touch electrode lines in the row direction (or column direction), and the common electrode CE or touch electrode in the column direction (or row direction). The sensing signal is received through the lines, and sensing data is generated based on the received sensing signal and supplied to the touch controller (T-CTR). The touch controller T-CTR detects the presence or absence of a touch or touch coordinates based on the sensed data.

When a touch is sensed based on self-capacitance, the common electrode CE on the touch panel TSP may be an electrode electrically separated from each other.

The common electrode driving circuit CDC supplies a driving signal to all or part of the plurality of common electrodes CE, receives a sensing signal from the common electrode CE to which the driving signal is supplied, and senses based on the received sensing signal. It generates data and supplies it to the touch controller (T-CTR). The touch controller T-CTR detects the presence or absence of a touch or touch coordinates based on the sensed data.

As described above, the touch display device according to embodiments of the present invention may sense a touch based on self-capacitance or may sense a touch based on mutual-capacitance. However, hereinafter, for convenience of description, sensing a touch based on self-capacitance will be described as an example.

As described above, the touch panel TSP is embedded in the display panel DISP. That is, a plurality of common electrodes CE serving as a touch electrode (touch sensor) and a plurality of signal lines SL connected thereto are embedded in the display panel DISP.

In this case, in the process step of manufacturing the display panel DISP, a plurality of common electrodes CE and a plurality of signal lines SL may be formed.

The above-described common electrode driving circuit CDC and data driving circuit DDC may be integrated and implemented.

The display controller D-CTR and the touch controller T-CTR may be configured separately or may be integrated.

3 is a diagram illustrating a display panel DISP having a built-in touch panel TSP in the touch display device according to embodiments of the present invention.

When the touch panel TSP is embedded in the display panel DISP, the plurality of common electrodes CE disposed in the touch area of the display panel DISP may be common electrodes used for driving the display. In this case, as an example, the display panel DISP may be of various types such as a liquid crystal display panel and an organic light emitting display panel.

Accordingly, a common voltage may be applied to the plurality of common electrodes CE for image display, and a driving signal may be applied to all or part of the plurality of common electrodes CE for touch sensing.

Meanwhile, the display panel DISP may be an organic light emitting display panel. In this case, the plurality of common electrodes CE and the plurality of signal lines SL are disposed on the entire surface of the display panel DISP and are disposed on an encapsulation layer disposed on the common electrode to which the common voltage is applied. can

Here, the common electrode disposed on the front surface of the display panel DISP, which is an organic light emitting display panel, is, for example, an anode electrode (corresponding to a pixel electrode) of an organic light emitting diode (OLED) in each subpixel SP. ) and the cathode electrode may be the cathode electrode, and the common voltage may be the cathode voltage.

In this case, each of the plurality of common electrodes CE may have an electrode shape without an opening. In this case, each of the plurality of common electrodes CE may be a transparent electrode for light emission from the sub-pixels SP.

Alternatively, each of the plurality of common electrodes CE may be a mesh-type electrode having a plurality of openings. In this case, each opening in each of the plurality of common electrodes CE may correspond to a light emitting region (eg, a region in which a part of the anode electrode is located) of the subpixel SP.

Meanwhile, in relation to the size of the common electrode, an area of each of the plurality of common electrodes CE may overlap an area of two or more sub-pixels SP.

That is, the area size of one common electrode CE may correspond to the area size of two or more sub-pixels SP.

One common electrode CE may overlap two or more gate lines GL.

One common electrode CE and two or more gate lines GL are insulated from each other.

One common electrode CE may overlap two or more data lines DL.

One common electrode CE and two or more data lines DL are insulated from each other.

2 and 3 , the plurality of signal lines SL are insulated from each other in the touch panel TSP.

2 and 3 , the plurality of signal lines SL may be arranged in the same direction as the plurality of data lines DL.

In this case, the data lines DL parallel to the signal line SL affect the common electrode CE disposed in the same direction. That is, the voltage state of the data lines DL parallel to the signal line SL affects the voltage state of the common electrode CE disposed in the same direction.

Alternatively, the plurality of signal lines SL may be arranged in the same direction as the plurality of gate lines GL.

In this case, the gate lines GL parallel to the signal line SL affect the common electrode CE disposed in the same direction. That is, the voltage state of the gate lines GL parallel to the signal line SL affects the voltage state of the common electrode CE disposed in the same direction.

4 is a time division driving timing diagram of a touch display device according to embodiments of the present invention.

Referring to FIG. 4 , the touch display device according to embodiments of the present invention may perform display driving and touch driving in different time zones.

That is, the touch display device according to embodiments of the present invention may perform display driving and touch driving by time division. This driving method is called a time division driving method.

The touch display device according to embodiments of the present invention may use the synchronization signal TSYNC to distinguish the display driving period from the touch driving period.

For example, in the synchronization signal TSYNC, a first level (eg, a high level or a low level) may indicate a display driving period, and a second level (eg, a low level or a high level) may indicate a touch driving period. .

During the touch driving period, all or part of the plurality of common electrodes CE receives the driving signal TDS. During the display driving period, the plurality of common electrodes CE may be floated, grounded to the ground, or a specific DC voltage may be applied.

That is, the common electrode CE may receive the common voltage Vcom for driving the display during the display driving period and may receive the driving signal TDS during the touch driving period.

The driving signal TDS applied to the common electrode CE during the touch driving period may be a DC voltage or a signal whose voltage level is changed. When the driving signal TDS is a signal whose voltage level is changed, the driving signal TDS may also be referred to as a modulation signal, a pulse signal, or an AC signal.

Meanwhile, during the touch driving period, while the driving signal TDS is applied to the common electrode CE, the common electrode CE may form a parasitic capacitance with other surrounding electrodes. Such parasitic capacitance may degrade touch sensitivity.

Accordingly, the touch display device may apply the load-free driving signal to other electrodes around the common electrode CE while the driving signal TDS is applied to the common electrode CE during the touch driving period.

The load-free driving signal LFD may be a driving signal TDS or a signal corresponding to at least one of a frequency, a phase, a voltage polarity, and an amplitude of the driving signal TDS.

Other electrodes around the common electrode CE may be data lines, gate lines, or other common electrodes, and may be all electrodes or signal wires in the vicinity.

During the touch driving period, while the driving signal TDS is applied to the common electrode CE, one or more data lines positioned around the common electrode CE or load-free driving to all data lines in the display panel DIPS A signal LFD_DATA may be applied.

During the touch driving period, while the driving signal TDS is applied to the common electrode CE, one or more gate lines positioned around the common electrode CE or load-free driving to all gate lines in the display panel DIPS A signal LFD_GATE may be applied.

During the touch driving period, while the driving signal TDS is applied to the common electrode CE, one or more common electrodes CE positioned around the common electrode CE or all other common electrodes CE in the display panel DIPS CE), the load-free driving signal LFD_Vcom may be applied.

When the touch display device according to the embodiments of the present invention is driven by the time division driving method, since the frame time must be divided into the display driving period and the touch driving period to be used, the display driving time may be insufficient.

This lack of driving time for the display may cause a situation in which a capacitor for displaying an image (eg, a capacitor between a pixel electrode and a common electrode, etc.) cannot be charged as much as necessary.

Accordingly, in a situation in which more display driving time is required, such as in high resolution, the touch display device according to embodiments of the present invention may simultaneously perform display driving and touch driving.

5 is a time-free driving timing diagram of a touch display device according to embodiments of the present invention.

Referring to FIG. 5 , the touch display device according to embodiments of the present invention may simultaneously perform display driving and touch driving. Such a driving method is called a Time Free Driving (TFD) method.

Accordingly, the touch display device according to embodiments of the present invention may not require a synchronization signal TSYNC for distinguishing the display driving period from the touch driving period.

When the touch display device according to the embodiments of the present invention performs time-free driving, display driving and touch driving may be performed during an active time among an active time and a blank time defined by the vertical synchronization signal Vsync. . Here, one active time may correspond to one display frame time.

Accordingly, in the case of performing time-free driving, the touch display device according to embodiments of the present invention operates a plurality of gate lines GL to drive the display during the active time defined by the vertical synchronization signal Vsync. While sequentially driving, a data voltage for image display may be supplied to the data lines DL and, at the same time, a driving signal TDS may be supplied to the plurality of common electrodes CE for touch driving.

Accordingly, the touch display device according to the embodiments of the present invention may sense a touch by a finger and/or a pen while displaying an image through display driving by performing a driving operation in a time-free driving method.

Meanwhile, the touch display device according to embodiments of the present invention may simultaneously perform display driving and touch driving in all frame times (ie, all active times).

On the other hand, in the touch display device according to the embodiments of the present invention, only display driving is performed in some frame times (active time), and display driving and touch driving are simultaneously performed in some other frame times (active time), , in some cases, only touch driving may be performed in some frame time (active time).

On the other hand, in the touch display device according to the embodiments of the present invention, a driving signal TDS having a variable voltage level during an active time is supplied to the common electrode CE, and a driving signal TDS having a variable voltage level even during a blank time is supplied. TDS) can be supplied to the common electrode CE (Case 1).

Alternatively, the touch display device according to the embodiments of the present invention may float the common electrode CE, supply a DC voltage, or supply a specific reference voltage (eg, a ground voltage) during the blank time (Case 2). ). This may be applied when the blank time is used as a special time for pen touch driving.

As described above, when the touch display device performs display driving and touch driving simultaneously in a time-free driving method, it is possible to prevent a situation in which display driving time is insufficient due to touch driving. Accordingly, it is possible to realize a high resolution while performing touch sensing.

6 is a diagram illustrating a ground environment of a touch display device according to embodiments of the present invention, and FIG. 7 is a time-free driving timing diagram during ground modulation in a touch display device according to embodiments of the present invention.

Referring to FIG. 6 , the touch display device according to embodiments of the present invention has two types of ground GND1 and GND2 .

The touch controller T-CTR, the display controller D-CTR, and the like may be grounded to the primary ground GND1 among the two grounds GND1 and GND2.

The display panel DISP and the like may be grounded to the secondary ground GND2 among the two grounds GND1 and GND2 .

Since the common electrode driving circuit CDC exchanges signals between the touch controller T-CTR grounded to the primary ground GND1 and the display panel DISP grounded to the secondary ground GND2, the primary Both the ground GND1 and the secondary ground GND2 may be grounded.

In addition, since the data driving circuit DDC sends and receives a signal between the display controller D-CTR grounded to the primary ground GND1 and the display panel DISP grounded to the secondary ground GND2, 1 Both the secondary ground GND1 and the secondary ground GND2 may be grounded.

Meanwhile, the primary ground GND1 may be a ground wire or a ground electrode disposed on the display panel DISP, an external structure such as an outer cover of the display panel DISP, or a wire or electrode disposed on the external structure. . In addition, the secondary ground GND2 may be a ground wire or a ground electrode disposed on the display panel DISP, an external structure such as an outer cover of the display panel DISP, or a wire or electrode disposed on the external structure. .

Referring to FIG. 6 , the touch display device according to embodiments of the present invention may further include a ground modulation circuit (GMC) for performing ground modulation.

In the ground modulation circuit GMC, one of the primary ground voltage Vgnd1 of the primary ground GND1 and the secondary ground voltage Vgnd2 of the secondary ground GND2 is modulated with respect to the other one. Modulation processing can be performed to achieve this.

Referring to FIG. 6 , the secondary ground voltage Vgnd2 of the secondary ground GND2 can be viewed as a modulated ground voltage with respect to the primary ground voltage Vgnd1 of the primary ground GND1.

Also, the primary ground voltage Vgnd1 of the primary ground GND1 may be viewed as a modulated ground voltage with respect to the secondary ground voltage Vgnd2 of the secondary ground GND2.

That is, looking at the secondary ground voltage Vgnd2 based on the primary ground voltage Vgnd1, the secondary ground voltage Vgnd2 appears to be a modulated signal (modulated ground voltage) whose voltage level is variable. Looking at the primary ground voltage Vgnd1 based on the secondary ground voltage Vgnd2, the primary ground voltage Vgnd1 appears to be a modulated signal (modulated ground voltage) whose voltage level is variable.

The driving signal TDS applied to the common electrodes CE in the display panel DISP by grounding the display panel DISP to the secondary ground GND2 having the secondary ground voltage Vgnd2 in the form of a modulated signal can swing like the secondary ground voltage (Vgnd2).

As described above, the touch display device can stably drive the display and the touch at the same time in a time-free driving method using the two grounds GND1 and GND2.

When the touch display device performs display driving and touch driving simultaneously in a time-free driving method, data is transmitted to the plurality of data lines DL while the driving signal TDS is applied to one or more of the plurality of common electrodes CE. A voltage may be applied.

In this case, the driving signal TDS applied to one or more of the plurality of common electrodes CE may have the secondary ground voltage Vgnd2 of the secondary ground GND2 to which the display panel DISP is grounded, the frequency, the phase, One or more of signal characteristics such as voltage polarity and amplitude may correspond.

On the other hand, when the plurality of common electrodes CE are divided common electrodes to which a common voltage used for driving a display is applied, the driving signal TDS applied to one or more of the plurality of common electrodes CE is required for driving the display. It may be a common voltage (Vcom).

When the touch display device according to the embodiments of the present invention performs display driving and touch driving at the same time according to a time-free driving method, the driving signal TDS and the common voltage Vcom may be regarded as the same below. .

Referring to FIG. 7 , in the touch display device according to the embodiments of the present invention, during the display driving period (ie, during the active time), a driving signal TDS having a variable voltage level is transmitted to a plurality of common electrodes CE. is supplied

The driving signal TDS supplied to the plurality of common electrodes CE is a touch driving signal for driving a touch and also a common voltage Vcom forming a capacitance with each pixel voltage (data voltage) for image display.

Referring to FIG. 7 , the driving signal TDS applied to the plurality of common electrodes CE disposed on the display panel DISP is a secondary ground voltage of the secondary ground GND2 to which the display panel DISP is grounded. (Vgnd2) may correspond to one or more of frequency, phase, voltage polarity, and amplitude.

Referring to the example of FIG. 7 , while the display driving and the touch driving are simultaneously performed (ie, during the active time), the secondary ground voltage Vgnd2 of the secondary ground GND2 to which the display panel DISP is grounded is ΔV. The voltage level can vary between V0 and V0+ΔV with an amplitude of . The driving signal TDS applied to the common electrode CE may have an amplitude of ΔV and a voltage level may vary between V1 and V1+ΔV.

As shown in the example of FIG. 7 , the secondary ground voltage Vgnd2 of the secondary ground GND2 to which the display panel DISP is grounded and the driving signal TDS applied to the common electrode CE are, in frequency, phase, At least one of amplitude and signal polarity may be the same.

However, when the voltage level is changed, the high level voltage and the low level voltage may be the same (V0=V1) or different from each other (V0≠V1).

As shown in FIG. 7 , the vertical synchronization signal Vsync maintains a second level (eg, a high level or a low level) during the active time, and maintains a first level (eg, a low level or a high level) during the blank time. can keep In this case, between the first levels (eg, low level or high level) may be defined as one display frame.

Alternatively, the vertical synchronization signal Vsync may maintain a first level (eg, a low level or a high level) during the active time and maintain a second level (eg, a high level or a low level) during the blank time. In this case, between two pulses having a second level (eg, a high level or a low level) may be defined as one display frame.

8 is a diagram illustrating a touch driving circuit of a touch display device according to embodiments of the present invention, and FIG. 9 is a diagram illustrating one operation performed by a common electrode driving circuit CDC of a touch display device according to embodiments of the present invention. It is a diagram showing a touch driving operation for a common electrode column.

Referring to FIG. 8 , the common electrode driving circuit CDC according to embodiments of the present invention includes a first multiplexer circuit MUX1, a sensing unit block SUB including a plurality of sensing units SU, and a second It may include a multiplexer circuit MUX2 and an analog-to-digital converter ADC.

The first multiplexer circuit MUX1 may include one or two or more multiplexers. The second multiplexer circuit MUX2 may include one or two or more multiplexers.

Referring to FIG. 8 , each sensing unit SU may include a pre-amplifier (Pre-AMP), an integrator (INTG), a sample and hold circuit (SHA), and the like.

One pre-amplifier (Pre-AMP) may be electrically connected to one or two or more common electrodes (CE).

For example, as shown in FIG. 9 , one pre-amplifier (Pre-AMP) includes a plurality of common electrodes (CE1, CE2, CE3, CE4, CE5) included in one common electrode column (CEC: CE Column). , ......) can be electrically connected to.

Referring to FIG. 9 , one pre-amplifier (Pre-AMP) is selected as a sensing target while rotating among one or more connectable common electrodes (CE1, CE2, CE3, CE4, CE5, ...). The driving signal TDS may be supplied to one common electrode to be sensed (eg, CE1), and the sensing signal may be received from the common electrode to be sensed (eg, CE1) to which the driving signal TDS is applied.

Referring to FIG. 9 , the multiplexer MUX included in the first multiplexer circuit MUX1 includes a plurality of common electrodes CE1 , CE2 , CE3 , CE4 , CE5 included in the common electrode column CEC. , ...... ), which is a common electrode selected as a sensing target, connects the sensing target common electrode CE1 with the pre-amplifier (Pre-AMP).

That is, the multiplexer MUX connects the node b connected to the pre-amplifier with the node a1 connected to the selected sensing target common electrode CE1.

Accordingly, the pre-amplifier (Pre-AMP) receives the common voltage (Vcom) corresponding to the driving signal (TDS) output from the power management integrated circuit (PMIC) through the first input terminal (I1) and receives the second input terminal ( output as I2).

The common voltage Vcom output from the second input terminal I2 of the pre-amplifier is supplied to the sensing target common electrode CE1 selected by the multiplexer MUX.

The multiplexer MUX is a plurality of common electrodes CE1, CE2, CE3, CE4, CE5, ...... , included in the corresponding common electrode column CEC, except for the sensing target common electrode CE1 The nodes (a2, a3, a4, a5, ...... ) connected to the non-sensing target common electrodes (CE2, CE3, CE4, CE5, ...... ) are connected to the power management integrated circuit (PMIC). It connects in common to node c that is directly connected to .

Accordingly, the non-sensing target common electrodes CE2, CE3, CE4, CE5, among the plurality of common electrodes CE1, CE2, CE3, CE4, CE5, ...... ...... ) can directly receive the common voltage (Vcom) without going through the pre-amplifier (Pre-AMP).

Thereafter, the pre-amplifier (Pre-AMP) may receive the sensing signal from the sensing target common electrode CE1. The feedback capacitor Cfb is charged by the sensing signal thus received, and accordingly, a signal output to the output terminal O of the pre-amplifier may be input to the integrator INTG.

The pre-amplifier (Pre-AMP) and the integrator (INTG) may be implemented integrally.

The integrator (INTG) integrates the signal output from the pre-amplifier (Pre-AMP).

The analog-to-digital converter ADC may output touch sensing data obtained by converting the integral value output to the integrator INTG into a digital value to the touch controller T-CTR.

The analog-to-digital converter ADC may output sensing data to the touch controller T-CTR grounded to the primary ground GND1.

The pre-amplifier may receive a sensing signal from the common electrode CE disposed on the display panel DISP grounded to a secondary ground GND2 that is a different ground from the primary ground GND1. When the common electrode driving circuit CDC is used, the touch sensing signal is received from the common electrode CE disposed on the display panel DISP grounded to the secondary ground GND2, which is the ground, and the primary ground GND1 is used. By outputting touch detection data to the touch controller (D-CTR) grounded to , it is possible to enable touch detection in a touch display device having two grounds (GND1, GND2).

Meanwhile, referring to FIG. 8 , the common electrode driving circuit CDC according to embodiments of the present invention may further include a signal transmission circuit STC for signal transmission with the touch controller T-CTR. In this case, the signal transfer circuit STC included in the common electrode driving circuit CDC according to embodiments of the present invention may be grounded to both the primary ground GND1 and the secondary ground GND2.

10 is a view showing a touch driving operation for the touch panel TSP performed by the common electrode driving circuit CDC of the touch display device according to the embodiments of the present invention, and FIG. A diagram for explaining a common voltage ripple (Vcom ripple) phenomenon that occurs as a noise component of a common voltage (Vcom) during touch driving of a touch display device according to the present invention and a touch sensing failure according thereto.

As shown in FIG. 10 , for convenience of explanation, nine common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE It is assumed that 3-1, CE 3-2, CE 3-3) are disposed in the touch area and arranged in 3 rows and 3 columns.

9 common electrodes (CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) One or more signal lines SL are connected to each.

The first common electrode column CEC #1 includes three common electrodes CE 1-1, CE 1-2, and CE 1-3, and the second common electrode column CEC #2 includes three common electrodes. (CE 2-1, CE 2-2, CE 2-3), and the third common electrode column (CEC #3) has three common electrodes CE 3-1, CE 3-2, CE 3-3. ) is included.

The signal line direction and the common electrode column direction correspond to the data line direction.

Meanwhile, there may be three preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) corresponding to the three common electrode columns (CEC #1, CEC #2, CEC #3). .

When driven in the time-free driving method, the common electrode driving circuit CDC includes nine common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2 A common voltage Vcom is supplied to all -3, CE 3-1, CE 3-2, CE 3-3), and the nine common electrodes CE 1-1 and CE 1 are provided by the first multiplexer circuit MUX1. -2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) receive a detection signal from the detect

In the example of FIG. 10 , the common electrodes CE 1-1, CE 2-1, and CE 3-1 positioned in the first row in each of the three common electrode columns CEC #1, CEC #2, and CEC #3 ) is a common electrode selected as a "sensing target common electrode" by the first multiplexer circuit MUX1.

Common electrodes (CE 1-2, CE 1-3, CE 2-2, CE 2) located in the second and third rows in each of the three common electrode columns (CEC #1, CEC #2, CEC #3) -3, CE 3-2, CE 3-3) are common electrodes selected as the "non-sensing target common electrode" by the first multiplexer circuit MUX1.

The common electrode driving circuit CDC receives the common voltage Vcom output from the power management integrated circuit PMIC through the common voltage buffer BUF.

The common electrode driving circuit CDC transmits the common voltage Vcom output from the common voltage buffer BUF through the six amplifiers AMP to the six non-sensing target common electrodes CE 1-2, CE 1-3, CE 2-2, CE 2-3, CE 3-2, CE 3-3) can be supplied.

The common electrode driving circuit CDC includes three preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP) corresponding to the three common electrode columns (CEC #1, CEC #2, CEC #3). A common voltage Vcom is supplied to the first input terminal I1 of #3).

Accordingly, the first of the three preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) corresponding to the three common electrode columns (CEC #1, CEC #2, CEC #3) The common voltage Vcom input to the input terminal I1 is output to the second input terminal I2 of the three preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3).

The common voltage (Vcom) output to the second input terminal (I2) of the three preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) is , CE 2-1, CE 3-1).

Thereafter, the common electrode driving circuit CDC receives the common voltage Vcom through the second input terminal I2 of the three preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3). A sensing signal is received from the applied three sensing target common electrodes CE 1-1, CE 2-1, CE 3-1. Thereafter, the signals output from the output terminals O of the three preamplifiers (Pre-AMP #1, Pre-AMP #2, and Pre-AMP #3) are input to the three integrators INTG.

In this way, in each of the three common electrode columns CEC #1, CEC #2, and CEC #3, the common electrodes CE 1-1, CE 2-1, CE 3-1 located in the first row are “detected”. After the detection of "target common electrode" is completed, thereafter, the common electrode driving circuit CDC, through the first multiplexer circuit MUX1, performs three common electrode columns CEC #1, CEC #2, and CEC #3. In each of the common electrodes (CE 1-2, CE 2-2, CE 3-2) positioned in the second row are selected as the “common electrode to be detected”, and the common electrodes CE positioned in the first and third rows are selected. 1-1, CE 1-3, CE 2-1, CE 2-3, CE 3-1, CE 3-3), select the "non-sensing target common electrode" and repeat the above-mentioned touch driving operation in the same way do.

In this way, in each of the three common electrode columns (CEC #1, CEC #2, CEC #3), the common electrodes CE 1-2, CE 2-2, CE 3-2 located in the second row are "detected". After the detection of "target common electrode" is completed, thereafter, the common electrode driving circuit CDC, through the first multiplexer circuit MUX1, performs three common electrode columns CEC #1, CEC #2, and CEC #3. In each of the common electrodes (CE 1-3, CE 2-3, CE 3-3) positioned in the third row are selected as the “common electrode to be detected”, and the common electrodes CE positioned in the first and second rows are selected. 1-1, CE 1-2, CE 2-1, CE 2-2, CE 3-1, CE 3-2), select the “non-sensing target common electrode” and repeat the above-mentioned touch driving operation in the same way do.

In this way, in each of the three common electrode columns (CEC #1, CEC #2, CEC #3), the common electrodes (CE 1-3, CE 2-3, CE 3-3) located in the third row are “detected”. When the sensing of "target common electrode" is completed, the sensing of the entire area of the display panel DISP in which the touch panel TSP is embedded is completed.

Accordingly, the touch controller T-CTR may calculate the presence or absence of a touch in the entire area of the display panel DISP or the touch coordinates based on the touch sensing data generated and output by the common electrode driving circuit CDC. have.

As described above with reference to FIG. 10 , during the touch driving operation, the common voltage Vcom is simultaneously applied to the sensing target common electrode (Sensing Target CE) and the non-sensing target common electrode (Non-sensing target CE). .

The common voltage Vcom applied to the common electrode to be sensed is a driving signal for touch sensing. The common voltage Vcom applied to the non-sensing common electrode may be a load free driving signal for preventing unnecessary parasitic capacitance from being formed between the sensing target common electrode and the non-sensing common electrode.

In addition, in the case of the time-free driving method, the common voltage Vcom applied to all common electrodes CE including the common electrode to be sensed and the common electrode not to be sensed is applied to the pixel electrode in each subpixel for image display. It is also the voltage that forms the pixel voltage and capacitance.

Meanwhile, referring to FIGS. 10 and 11 , when display driving and touch driving are simultaneously performed in a time-free driving method, if the common voltage Vcom is not stable and fluctuates, touch sensitivity and display quality are greatly reduced. can

For example, the common electrodes CE, the signal lines SL, and the data lines DL are arranged according to the arrangement structure, the driving method, etc., due to a change in the data voltage applied to the data line DL. A change in the common voltage Vcom applied to the electrodes CE may occur.

When this variation of the common voltage Vcom occurs, a ripple (hereinafter, referred to as a common voltage ripple Vcom Ripple) may be generated as a noise component in the signal waveform of the common voltage Vcom.

The common voltage Vcom applied to the plurality of common electrodes CE according to the time-free driving method is a modulation signal whose voltage level is changed, but the signal waveforms shown in FIGS. 10 and 11 are, for convenience of explanation, DC It shows that the common voltage ripple Vcom ripple occurs in the positive direction and the negative direction at the common voltage Vcom of the voltage.

As illustrated in FIG. 11 , when the common voltage ripple Vcom Ripple is generated, an undesired change may occur in the sensed data (touch sensed data), which may result in a touch sense failure.

In addition, the generation of the common voltage ripple Vcom Ripple may affect display operation as well as touch sensing failure, thereby causing display-related defects such as crosstalk.

Accordingly, in the touch display device according to the embodiments of the present invention, a common voltage that may be generated in the common electrode CE when the common electrode CE is driven when the touch is sensed by the time-free driving method or the time division driving method. It is possible to prevent deterioration of touch sensitivity and display quality due to ripple.

12 and 13 are diagrams illustrating a driving operation of a common electrode when a display of a touch display device is driven according to embodiments of the present invention.

According to the example of FIG. 12 , in the display panel DISP, nine common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, and CE 3-3) are arranged in three rows and three columns, so three common electrode columns CEC #1, CEC #2, and CEC #3 exist in the display panel DISP. . Here, in the display panel DISP, each of the three common electrode columns CEC #1, CEC #2, and CEC #3 may correspond to a data line direction.

Common electrodes (CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-) arranged on the display panel DISP 2, CE 3-3) also serve as a touch electrode, so they must all be electrically separated from the display panel DISP.

Meanwhile, referring to FIG. 13 , in the display panel DISP, common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, and CE 3-3), since the data lines DL and the like are disposed, a large change in the data voltage Vdata in the data lines DL is caused by the common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) Vcom) causing voltage instability.

For this reason, during the display driving period, the touch driving period, or the period in which the display driving and the touch driving are performed together, the common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2 A ripple may occur in the common voltage Vcom applied to -2, CE 2-3, CE 3-1, CE 3-2, CE 3-3).

Meanwhile, referring to FIG. 13 , a large change in the data voltage Vdata in the data lines DL may be different for each data line column. The degree may be significantly different for each column (CEC #1, CEC #2, CEC #3).

However, through one output buffer BUF, the common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1 , CE 3-2, CE 3-3) have a structure in which the common voltage Vcom is supplied. It is difficult to reduce or eliminate the instability of (Vcom).

Below, during the display driving period, the touch driving period, or the period in which the display driving and the touch driving are performed together, the common voltage Vcom that may be differently generated for each common electrode column (CEC #1, CEC #2, CEC #3) ), a method and circuit structure that can effectively reduce or eliminate the instability of

14 is a diagram for explaining a common voltage compensation principle in a common voltage compensation system of a touch display device according to embodiments of the present invention, and FIG. 15 is a common voltage compensation system for a touch display device according to embodiments of the present invention. is a diagram schematically illustrating a common voltage compensation circuit CC, and FIG. 16 is a diagram illustrating a common voltage compensation system of a touch display device according to embodiments of the present invention.

14 and 15 , the common electrode driving circuit CDC receives a common voltage fed back from the display panel DISP, and inverts the polarity of the fed back feedback common voltage FB Vcom to output the common voltage compensation circuit. (CC) may be included.

The signal output from the common voltage compensation circuit CC is a signal in which the polarity of the feedback common voltage FB Vcom is inverted.

Hereinafter, the signal output from the common voltage compensation circuit CC is also referred to as an inverted common voltage INV Vcom.

The common electrode driving circuit CDC may further include an output circuit OC for outputting an output signal of the common voltage compensation circuit CC (ie, an inverted common voltage INV Vcom) or a common voltage corresponding thereto. .

The common electrode driving circuit CDC supplies an output signal (inverted common voltage INV Vcom) or a common voltage corresponding thereto of the common voltage compensation circuit CC to the display panel DISP through the output circuit OC. , it is possible to compensate for the instability of the common voltage Vcom, such as ripple occurring in the common voltage Vcom. This is called common voltage compensation processing.

The signal application state (voltage application state) of the common electrodes CE disposed on the display panel DISP is the common voltage Vcom that was already applied before the common voltage compensation process; this is the feedback common voltage FB Vcom and Corresponding) and the common voltage Vcom (corresponding to the inverted common voltage INV Vcom) applied with inverted polarity according to the common voltage compensation process is signally added to a compensation state. This compensation state may be a signal state in which a ripple is removed by combining two signals having different polarities.

Accordingly, through the above-described common voltage compensation process, the common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2 disposed on the display panel DISP. -3, CE 3-1, CE 3-2, CE 3-3) can remove or reduce the instability of the common voltage Vcom.

Referring to FIG. 15 , the common voltage compensation circuit CC has a feedback node NFB to which the common voltage FB Vcom fed back from the display panel DISP is applied.

The feedback node NFB may be electrically connected to a feedback line FBL additionally disposed on the display panel DISP.

Also, the common voltage compensation circuit CC may include an inverting amplifier INV-AMP that performs signal polarity inversion processing.

The inverting amplifier INV-AMP is electrically connected to the first input terminal N1 to which the first input voltage is applied, and the feedback node NFB, and a second input voltage corresponding to the fed back common voltage FB Vcom. It may have a second input terminal N2 to which this is applied, and an output terminal M outputting an output voltage.

The inverting amplifier INV-AMP may include an operational amplifier OP AMP, a first resistor R1 and a second resistor R2, and the like.

The first input voltage input to the first input terminal N1 may be a common voltage Vcom first input from the power management integrated circuit PMIC or the like.

The second input voltage input to the second input terminal N2 may be a feedback common voltage FB Vcom input through the feedback node NFB.

The output voltage output through the output terminal M may be a signal in which the polarity of the second input voltage is inverted.

The output voltage of the inverting amplifier INV-AMP may correspond to (-R2/R1)*(second input voltage).

Meanwhile, referring to FIG. 15 , the common voltage compensation circuit CC may further include a capacitor Cb connected between the feedback node NFB and the second input terminal N2 .

Through the capacitor Cb, the polarity of the feedback common voltage FB Vcom can be inverted more stably.

In embodiments of the present invention, the common voltage compensation system may include a common voltage compensation circuit CC and an output circuit OC.

In the common voltage compensation system, a common voltage compensation circuit (CC) composed of a feedback node (NFB), an inverting amplifier (INV-AMP), a capacitor (Cb), etc. 3) There can be one of each.

Also, one output circuit OC may exist for each common electrode column CEC #1, CEC #2, and CEC #3.

As shown in FIG. 16 , in the common voltage compensation system according to embodiments of the present invention, when three common electrode columns CEC #1, CEC #2, and CEC #3 are present in the display panel DISP , three common voltage compensation circuits (CC #1, CC #2, CC#3) and three output circuits (OC #1, OC #2, OC #3).

17 to 19 are exemplary views of a common voltage compensation system of a touch display device according to embodiments of the present invention.

17 and 18 , during the display driving period, all common electrodes CE 1-1, CE 1-2, and CE belonging to three common electrode columns CEC #1, CEC #2, and CEC #3 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) supply a common voltage (Vcom), and three common electrode columns ( For each CEC #1, CEC #2, CEC #3), the common voltage (Vcom) is fed back at a predetermined position, the polarity of the feedback common voltage (Vcom) is inverted, and the polarity inverted common voltage (INV Vcom) is converted into three common It can be supplied for each electrode row (CEC #1, CEC #2, CEC #3).

As illustrated in FIG. 17 , the positions at which the common voltage Vcom is fed back for each of the three common electrode columns CEC #1, CEC #2, and CEC #3 are the three common electrode columns CEC #1, CEC # 2, CEC #3) may be a specific common electrode (CE 1-1, CE 2-1, CE 3-1).

As illustrated in FIG. 17 , the positions at which the common voltage Vcom is fed back for each of the three common electrode columns CEC #1, CEC #2, and CEC #3 are the three common electrode columns CEC #1, CEC # 2, it may be a dummy electrode DE existing for each CEC #3).

Referring to FIG. 19 , during the touch driving period in the time division driving method or the time free driving method, all common electrodes CE 1 - belonging to three common electrode columns CEC #1, CEC #2, CEC #3 1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) A common voltage Vcom that plays a role is supplied, and the common voltage Vcom is fed back to each of the three common electrode columns (CEC #1, CEC #2, CEC #3) at a predetermined position, and the feedback common voltage Vcom is By inverting the polarity, the inverted common voltage INV Vcom may be supplied to each of the three common electrode columns CEC #1, CEC #2, and CEC #3.

In the example of FIG. 19 , in each of the three common electrode columns CEC #1, CEC #2, and CEC #3, the common electrodes CE 1-1, CE 2-1, and CE 3-1 located in the first row are Common electrodes to be sensed, and common electrodes (CE 1-2, CE 2-2, CE 3-2, CE 1-3, CE 2-3, CE 3-3) located in the second and third rows These are common electrodes that are load-free driving as the sensing target common electrodes.

Applied to common electrodes (CE 1-2, CE 2-2, CE 3-2, CE 1-3, CE 2-3, CE 3-3) located in the second and third rows, which are common electrodes not to be detected The common voltage Vcom used corresponds to the load-free driving signal LFD_Vcom.

As illustrated in FIG. 19 , the positions at which the common voltage Vcom is fed back for each of the three common electrode columns CEC #1, CEC #2, and CEC #3 are the three common electrode columns CEC #1, CEC # 2, it may be a dummy electrode DE existing for each CEC #3).

As another example, the position at which the common voltage Vcom is fed back for each of the three common electrode columns CEC #1, CEC #2, and CEC #3 is determined by the three common electrode columns CEC #1, CEC #2, and CEC # 3) It may be a specific common electrode CE 1-1, CE 2-1, CE 3-1.

The above will be described again below.

17 to 19 , for each common electrode column, a feedback line FBL electrically connecting a specific common electrode and the feedback node NFB of the common voltage compensation circuit CC is disposed on the display panel DISP can be

Through this, the common voltage compensation circuits CC #1, CC #2, and CC #3 may receive feedback of the common voltage Vcom from the display panel DISP.

Referring to FIG. 17 , as an example of a position at which the common voltage Vcom is fed back for each of three common electrode columns CEC #1, CEC #2, and CEC #3, a specific common electrode includes three common electrode columns ( In each of CEC #1, CEC #2, and CEC #3), the common electrodes CE 1-1, CE 2-1, and CE 3-1 may be the most distant from the common electrode driving circuit CDC.

Therefore, the common voltage compensation circuits CC #1, CC #2, and CC #3 in the common electrode driving circuit CDC receive feedback from the common voltage Vcom from a position where noise (ripple) is most severe, and thus effectively A common voltage compensation process may be performed.

18 and 19 , as another example of a position at which the common voltage Vcom is fed back for each of the three common electrode columns CEC #1, CEC #2, and CEC #3, the outer region of the display panel DISP It may be a dummy electrode DE positioned in the .

In this case, the display panel DISP includes the dummy electrode DE and the feedback node NFB of the common voltage compensation circuit CC for each of the three common electrode columns CEC #1, CEC #2, and CEC #3. A feedback line FBL electrically connecting may be disposed.

18 and 19 , the dummy electrode DE is a common electrode located farthest from the common electrode driving circuit CDC in each common electrode column CEC #1, CEC #2, and CEC #3. It can be located outside of (CE 1-1, CE 2-1, CE 3-1).

In this case, the common voltage compensation circuits CC #1, CC #2, and CC #3 in the common electrode driving circuit CDC are located at the positions where noise (ripple) is most severe without structural change related to the common electrode itself. By receiving a feedback of the common voltage Vcom from , an effective common voltage compensation process can be performed.

Meanwhile, the structure of the common voltage compensation system will be described again in terms of the time division driving method and the time free driving method.

First, in the case of driving in the time division driving method, display driving and touch driving are performed at different time zones.

Accordingly, during a display driving period in which a plurality of gate lines are sequentially driven, the common voltage Vcom has a constant voltage level, and during a touch driving period that is temporally different from the display driving period, the common voltage Vcom is a touch Since it should serve as the driving signal TDS, it may be a modulation signal whose voltage level is changed.

17 and 18 , during the display driving period, the output circuit OC may include a plurality of amplifiers AMP amplifying the output voltage and outputting the amplified output voltage to the signal line as a common voltage.

Such an amplifier AMP may be connected to each signal line SL, and by using it, the common electrodes CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2 -3, CE 3-1, CE 3-2, CE 3-3), the common voltage Vcom can be output with a desired size.

Referring to FIG. 19 , the output circuit OC includes the common electrodes CE 1-1 and CE 2- to be sensed in each common electrode column CEC #1, CEC #2, and CEC #3 during the touch driving period. 1, CE 3-1) and preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) that output a common voltage to the signal line (SL), and during the touch driving period, each common At least one non-sensing target common electrode (CE 1-2) except for the sensing target common electrode (CE 1-1, CE 2-1, CE 3-1) in the electrode column (CEC #1, CEC #2, CEC #3) , CE 1-3, CE 2-2, CE 2-3, CE 3-2, CE 3-3) includes one or more amplifiers (AMP) that output the common voltage (Vcom) to the signal line (SL) can do.

Preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) present in each common electrode column (CEC #1, CEC #2, CEC #3) are inverted amplifiers (INV-AMP) a first input terminal I1 connected to the output terminal M of the may include

One or more amplifiers (AMP) present in each common electrode column (CEC #1, CEC #2, CEC #3) have an input terminal connected to the output terminal (M) of the inverting amplifier (INV-AMP) and a common non-sensing target It may include an output terminal electrically connected to the signal line SL connected to the electrodes CE 1-2, CE 1-3, CE 2-2, CE 2-3, CE 3-2, CE 3-3. .

According to the above description, the common voltage compensation process can be effectively performed during touch driving according to the time division driving method.

Next, when driving in the time-free driving method, display driving and touch driving are performed simultaneously.

Therefore, during the display driving period (concept including the touch driving period) in which a plurality of gate lines are sequentially driven, the common voltage must also serve as the touch driving signal TDS, so it may be a modulation signal whose voltage level is changed. have.

In this case, the output circuit OC is connected to the sensing target common electrodes CE 1-1, CE 2-1, CE 3-1 in each common electrode column CEC #1, CEC #2, and CEC #3. Preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) that output a common voltage to the connected signal line (SL), and each common electrode column (CEC #1, CEC #2, CEC #) At least one non-sensing target (CE 1-2, CE 1-3, CE 2-2, CE 2-3) except for the common electrode to be detected (CE 1-1, CE 2-1, CE 3-1) in 3) , CE 3-2, CE 3-3) may include one or more amplifiers AMP for outputting a common voltage Vcom to the signal line SL connected to the CE 3-2 and CE 3-3).

The preamplifiers (Pre-AMP #1, Pre-AMP #2, Pre-AMP #3) present in each common electrode column (CEC #1, CEC #2, CEC #3) are,

A first input terminal I1 connected to the output terminal M of the inverting amplifier INV-AMP, a second input terminal I2 electrically connected to a signal line connected to a common electrode to be sensed, and a detection output signal It may include an output terminal (O) that is.

One or more amplifiers (AMP) present in each common electrode column (CEC #1, CEC #2, CEC #3) have an input terminal connected to the output terminal (M) of the inverting amplifier (INV-AMP) and a common non-sensing target It may include an output terminal electrically connected to the signal line SL connected to the electrodes CE 1-2, CE 1-3, CE 2-2, CE 2-3, CE 3-2, CE 3-3. .

According to the above description, the common voltage compensation process can be effectively performed during touch driving according to the time-free driving method.

Hereinafter, the display panel DISP for the above-described common voltage compensation will be described.

The display panel DISP according to embodiments of the present invention includes a plurality of data lines DL arranged in a first direction (eg, a column direction or a row direction), and a second direction (eg, a row direction) different from the first direction. direction or column direction), a plurality of common electrodes CE arranged in a column, and a plurality of signal lines SL electrically connected to the plurality of common electrodes CE, respectively. includes

In addition, as shown in FIGS. 17 to 19 , the display panel DISP according to embodiments of the present invention includes a plurality of common electrodes CE 1-1, CE 1-2, CE 1-3, and CE 2 . -1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) at least one specific common electrode (CE 1-1, CE 2-1, CE 3-1) electrically connected to, or a plurality of common electrodes (CE 1-1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2). , CE 3 - 3 ) may include one or more feedback lines FBL electrically connected to one or more other electrodes DE disposed outside.

In the display panel DISP according to the embodiments of the present invention, after the feedback signal (the feedback common voltage FB Vcom) is output to the outside (the common electrode driving circuit CDC) from the feedback line FBL, the external ( A signal (a signal corresponding to the inverted common voltage INV Vcom) supplied from the common electrode driving circuit CDC to the signal line SL has a polarity reversed from that of the feedback signal (the feedback common voltage FB Vcom). can have

When the display panel DISP is used, noise such as a ripple induced in the common voltage Vcom applied to the display panel DISP can be removed or reduced.

The feedback line FBL disposed on the display panel DISP may be longer than the longest signal line among the plurality of signal lines SL.

17 , in the display panel DISP, the specific common electrodes CE 1-1, CE 2-1, CE 3-1 connected to the feedback line FBL have a plurality of common electrodes CE 1- 1, CE 1-2, CE 1-3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3) display panel (DISP) pad It may be a common electrode (CE 1-1, CE 2-1, CE 3-1) located farthest from the region.

Here, the pad region of the display panel DISP is a region to which the common electrode driving circuit CDC is bonded.

Meanwhile, as shown in FIGS. 18 and 19 , in the display panel DISP, the other electrode DE connected to the feedback line FBL is a plurality of common electrodes CE 1-1, CE 1-2, CE 1 . -3, CE 2-1, CE 2-2, CE 2-3, CE 3-1, CE 3-2, CE 3-3), the most common electrode (CE 1-1, CE 2) located farthest from the pad area -1, CE 3-1).

According to the above-described structure of the display panel DISP, the common voltage Vcom may be fed back from a position where noise (ripple) is most severe, and effective common voltage compensation processing may be performed.

20 is a flowchart of a driving method according to embodiments of the present invention.

Referring to FIG. 20 , a driving method for driving a display panel DISP according to embodiments of the present invention includes the steps of supplying a common voltage Vcom to the display panel DISP ( S2010 ), and the display panel DISP. ) receiving the common voltage Vcom as feedback (S2020), inverting the polarity of the fed back common voltage FB Vcom (S2030), and applying the inverted common voltage INV Vcom to the display panel DISP ) may include a step of supplying (S2040) and the like.

By using the above-described driving method, the common voltage Vcom from which noise such as ripple is removed or reduced is stably supplied to the display panel DISP, so that display and touch sensing can be stably performed.

According to the present invention described above, the touch display device, the display panel DIS0, which can normally perform display driving and touch driving by removing or reducing noise such as ripple generated from a common electrode that is also used as a touch electrode, A common electrode driving circuit CDC and a driving method may be provided.

According to the present invention, a touch display device and a display panel capable of normally performing display driving and touch driving by time division by removing or reducing noise such as ripple generated from a common electrode commonly used for display driving and touch driving (DIS0), a common electrode driving circuit CDC, and a driving method may be provided.

According to the present invention, a touch display device and a display panel (DIS0) capable of normally performing display driving and touch driving at the same time by removing or reducing noise such as ripple generated in a common electrode commonly used for display driving and touch driving ), a common electrode driving circuit CDC and a driving method may be provided.

The above description and the accompanying drawings are merely illustrative of the technical idea of the present invention, and those of ordinary skill in the art to which the present invention pertains can combine configurations within a range that does not depart from the essential characteristics of the present invention. , various modifications and variations such as separation, substitution and alteration will be possible. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to illustrate, and the scope of the technical spirit of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

DISP: display panel
DDC: data driving circuit
GDC: gate driving circuit
D-CTR: Display Controller
CDC: Common electrode driving circuit
T-CTR: Touch Controller

Claims (18)

a display panel including a plurality of data lines and a plurality of gate lines, a plurality of common electrodes, and a plurality of signal lines electrically connected to the plurality of common electrodes, respectively;
a data driving circuit for outputting a data voltage to the data line;
a gate driving circuit outputting a gate signal to the gate line; and
a common electrode driving circuit for outputting a common voltage to the common electrode;
The common electrode driving circuit,
a common voltage compensation circuit that receives a common voltage fed back from a feedback line disposed on the display panel and outputs the inverted polarity of the fed back common voltage;
an output circuit for outputting a common voltage corresponding to the output signal of the common voltage compensation circuit to common electrodes arranged in one common electrode column among the plurality of common electrodes;
the output circuit outputs a common voltage corresponding to the output signal of the common voltage compensation circuit to signal lines electrically connected to the common electrodes arranged in the common electrode column;
the feedback line overlaps the common electrodes arranged in the common electrode column in the touch area of the display panel;
The feedback line and the signal lines are disposed in the same direction as a direction in which the plurality of data lines are disposed in the touch area.
According to claim 1,
The common voltage compensation circuit,
a feedback node to which the feedback line is connected and to which a common voltage fed back from the display panel is applied;
Inverting having a first input terminal to which a first input voltage is applied, a second input terminal electrically connected to the feedback node and to which a second input voltage corresponding to the fed back common voltage is applied, and an output terminal outputting an output voltage A touch display device including an amplifier.
3. The method of claim 2,
The feedback line electrically connecting a specific common electrode and a feedback node of the common voltage compensation circuit is disposed on the display panel for each common electrode column.
4. The method of claim 3,
The specific common electrode is
A touch display device which is a common electrode located farthest from the common electrode driving circuit in each common electrode column.
3. The method of claim 2,
a dummy electrode positioned in an outer region of the display panel and corresponding to each common electrode column is disposed;
and the feedback line electrically connecting the dummy electrode and a feedback node of the common voltage compensation circuit to each of the common electrode columns is disposed on the display panel.
6. The method of claim 5,
The dummy electrode is
In each of the common electrode columns, the touch display device is located outside the common electrode located farthest from the common electrode driving circuit.
3. The method of claim 2,
During a display driving period in which the plurality of gate lines are sequentially driven, the common voltage has a constant voltage level,
During a touch driving period that is temporally different from the display driving period, the common voltage is a modulation signal in which a voltage level is changed.
8. The method of claim 7,
The output circuit is
During the display driving period,
and a plurality of amplifiers for amplifying the output voltage and outputting the amplified output voltage to the signal line as the common voltage.
8. The method of claim 7,
The output circuit is
a preamplifier for outputting the common voltage to a signal line connected to a common electrode to be sensed in each common electrode column during the touch driving period;
at least one amplifier for outputting the common voltage to a signal line connected to one or more non-sensing common electrodes except for the sensing target common electrode in each common electrode column during the touch driving period;
The preamplifier is
A first input terminal connected to the output terminal of the inverting amplifier, a second input terminal electrically connected to a signal line connected to the sensing target common electrode, and an output terminal for outputting a detection output signal,
The amplifier is
and an input terminal connected to an output terminal of the inverting amplifier and an output terminal electrically connected to a signal line connected to the non-sensing target common electrode.
3. The method of claim 2,
During a display driving period in which the plurality of gate lines are sequentially driven, the common voltage is a modulation signal whose voltage level is changed.
11. The method of claim 10,
The output circuit is
a preamplifier for outputting the common voltage to a signal line connected to a common electrode to be sensed in each common electrode column;
at least one amplifier for outputting the common voltage to a signal line connected to at least one non-sensing target common electrode except for the sensing target common electrode in each common electrode column;
The preamplifier is
A first input terminal connected to the output terminal of the inverting amplifier, a second input terminal electrically connected to a signal line connected to the sensing target common electrode, and an output terminal for outputting a detection output signal,
The amplifier is
and an input terminal connected to an output terminal of the inverting amplifier and an output terminal electrically connected to a signal line connected to the non-sensing target common electrode.
3. The method of claim 2,
The common voltage compensation circuit,
and a capacitor connected between the feedback node and the second input terminal.
In the display panel,
a plurality of data lines arranged in a first direction;
a plurality of gate lines arranged in a second direction;
a plurality of common electrodes arranged in a column;
a plurality of signal lines electrically connected to the plurality of common electrodes; and
a feedback line electrically connected to a specific common electrode among the plurality of common electrodes or electrically connected to another electrode disposed outside the plurality of common electrodes;
After the feedback signal is output from the feedback line, the signal supplied to the signal lines electrically connected to the common electrodes arranged in one common electrode column among the plurality of common electrodes has a polarity reversed from the polarity of the feedback signal have,
the feedback line overlaps the common electrodes arranged in the common electrode column in the touch area of the display panel;
The feedback line and the signal lines are disposed in the same direction as a direction in which the plurality of data lines are disposed in the touch area.
14. The method of claim 13,
The feedback line is longer than a longest signal line among the plurality of signal lines.
14. The method of claim 13,
The specific common electrode is a common electrode located farthest from the pad area among the plurality of common electrodes.
14. The method of claim 13,
The other electrode is located outside the common electrode located farthest from the pad area among the plurality of common electrodes.
A common electrode driving circuit for driving a plurality of common electrodes disposed on a display panel, the common electrode driving circuit comprising:
a first input terminal to which a first input voltage is applied; a second input terminal electrically connected to a feedback line of the display panel and to which a second input voltage corresponding to a common voltage fed back from the feedback line is applied; an inverting amplifier having an output stage for outputting an output voltage in which the polarity of the voltage is inverted; and
an output circuit for outputting a common voltage corresponding to the output voltage to common electrodes arranged in one common electrode column among the plurality of common electrodes;
the output circuit outputs a common voltage corresponding to the output voltage to signal lines electrically connected to the common electrodes arranged in the common electrode column;
the feedback line overlaps the common electrodes arranged in the common electrode column in the touch area of the display panel;
The feedback line and the signal lines are disposed in the same direction as a direction in which a plurality of data lines for driving a display are disposed in the touch area.
A driving method for driving a display panel, comprising:
supplying a common voltage to signal lines electrically connected to common electrodes arranged in a common electrode column in the display panel;
receiving a common voltage feedback from a feedback line disposed on the display panel;
inverting the polarity of the fed back common voltage; and
supplying the common voltage with the inverted polarity from the display panel to signal lines electrically connected to common electrodes arranged in the common electrode column, respectively;
the feedback line overlaps the common electrodes arranged in the common electrode column in the touch area of the display panel;
The feedback line and the signal lines are arranged in the same direction as a direction in which a plurality of data lines for driving a display are arranged in the touch area.

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