Display device with integrated touch screen and method for driving the same

Disclosed is a display device with integrated touch screen. The display device includes a panel configured to include a plurality of electrodes divided into n groups; and a display driver IC configured to, apply a common voltage to the electrodes during a display driving mode of a first frame, apply a touch scan signal to a first group and a first adjacent electrode unit included in a second group during a touch driving mode of the first frame, apply the common voltage to the electrodes during the display driving mode of a second frame, and apply the touch scan signal to the second group and a second adjacent electrode unit included in the first group adjacent to the second group during the touch driving mode of the second frame.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims the benefit of the Korean Patent Application No. 10-2012-0149025 filed on Dec. 19, 2012, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND

Field of the Invention

The present invention relates to a display device, and more particularly, to a display device with integrated touch screen.

Discussion of the Related Art

Touch screens are a type of input device that is included in image display devices such as liquid crystal displays (LCDs), Field Emission Displays (FEDs), plasma display panels (PDPs), electroluminescent displays (ELDs), and electrophoretic displays (EPDs), and allows a user to input predetermined information by applying a pressure (i.e., pressing or touching) to a touch sensor of a touch screen while looking at the image display device.

Particularly, the demand of display devices with integrated in-cell type touch screen, which include a plurality of built-in elements configuring the touch screen for slimming portable terminals such as smart phones and tablet Personal Computers (PCs), is recently increasing.

General display devices with integrated in-cell type touch screen transfer touch data to a system once for each one vertical sync signal (Vsync) that defines one frame period. Hereinafter, driving of a related art display device with integrated in-cell type touch screen will be described with reference toFIG. 1.

FIG. 1is a timing chart showing signals during a display period and a touch sensing period based on one vertical sync signal, in a general display device with integrated touch screen.

In the general display device with integrated self-capacitive and in-cell type touch screen, as shown inFIG. 1, the display period and the touch sensing period are time-divided and driven according to the sync signal during one frame.

For example, a plurality of electrodes receive a common voltage to perform a display driving operation in the display period in units of a frame, and in the touch sensing period, the plurality of electrodes receive a touch sensing signal to perform a touch driving operation.

When the general display device with integrated touch screen is a high-resolution display device, the number of data to input increases in the display driving operation, and for this reason, time for the display driving operation also increases. On the other hand, time for the touch driving operation is insufficient.

SUMMARY

Accordingly, the present invention is directed to provide display device with integrated touch screen and a driving method thereof that substantially obviate one or more problems due to limitations and disadvantages of the related art.

An aspect of the present invention is directed to provide a display device with integrated touch screen, which can increase a display driving time and reduce a touch driving time.

To achieve these and other advantages and in accordance with the purpose of the invention, as embodied and broadly described herein, there is provided a display device with integrated touch screen including: a panel configured to include a plurality of electrodes that are divided into n number of groups (where n is an integer equal to or more than two); a display driver IC configured to, apply a common voltage to the plurality of electrodes during a display driving mode of a first frame, apply a touch scan signal to a first group of the n groups and a first adjacent electrode unit included in a second group adjacent to the first group during a touch driving mode of the first frame, apply the common voltage to the plurality of electrodes during the display driving mode of a second frame, and apply the touch scan signal to the second group and a second adjacent electrode unit included in the first group adjacent to the second group during the touch driving mode of the second frame; and a touch IC configured to generate the touch scan signal, and apply the touch scan signal to the display driver IC.

In another aspect of the present invention, there is provided a method of driving a display device with integrated touch screen, which includes: a panel configured to include a plurality of electrodes that are divided into n number of groups (where n is an integer equal to or more than two); a display driver IC that applies a common voltage or a touch scan signal to the plurality of electrodes; and a touch IC configured to generate the touch scan signal, and apply the touch scan signal to the display driver IC, including: applying the common voltage to the plurality of electrodes during a display driving mode of a first frame; applying the touch scan signal to a first group of the n groups and a first adjacent electrode unit included in a second group adjacent to the first group, during a touch driving mode of the first frame; applying the common voltage to the plurality of electrodes during the display driving mode of a second frame; and applying the touch scan signal to the second group and a second adjacent electrode unit included in the first group adjacent to the second group, during the touch driving mode of the second frame.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, for convenience of a description, a display device with integrated touch screen according to embodiments of the present invention will be exemplarily described as being an LCD device, but the present invention is not limited thereto. The present invention may be applied to various display devices such as FEDs, PDPs, ELDs, and EPDs. Also, a description on the general configuration of an LCD device is not provided.

In a display device with integrated touch screen according to an embodiment of the present invention, a plurality of electrodes are divided into n number of groups, and a touch scan signal is sequentially applied to the n groups. However, for convenience of a description, the below description will be made on a method where the electrodes are divided into two groups. Therefore, the present invention is not limited to the method where the electrodes are divided into the two groups, and the electrodes may be divided into three or more groups.

FIG. 2is a diagram illustrating a configuration of a display device with integrated touch screen according to an embodiment of the present invention, andFIG. 3is a diagram illustrating, in detail, a connection relationship between a panel and a display driver IC of the display device with integrated touch screen according to an embodiment of the present invention.

The display device with integrated touch screen according to an embodiment of the present invention, as illustrated inFIG. 2, includes a panel100, a display driver IC200, and a touch IC300.

First, the panel100includes a built-in touch screen (not shown), which detects a touch position of a user. In particular, the touch screen applied to the present invention is a self-capacitive and in-cell type touch screen in which a display driving operation and a touch driving operation are temporally divided and performed.

The panel100may be configured as a type in which a liquid crystal layer is formed between two substrates. In this case, a plurality of gate lines, a plurality of data lines intersecting the gate lines, a plurality of thin film transistors (TFTs) that are respectively formed in a plurality of areas defined by intersections between the data lines and the gate lines, and a plurality of pixels (which are arranged in a matrix type due to an intersection structure of the data lines and the gate lines) are disposed on a lower substrate of the panel100.

The panel100includes a plurality of electrodes101, which are divided into two groups, and a plurality of lines.

The plurality of electrodes101are formed in a pixel area of the panel100to overlap a plurality of pixel electrodes. In other words, the plurality of electrodes101are not formed in each pixel but are formed in an area overlapping a plurality of pixels.

When a driving mode of the panel100is a display driving mode, each of the electrodes101acts as a common electrode, which drives a liquid crystal, along with a pixel electrode formed in a corresponding pixel. When the driving mode of the panel100is a touch driving mode, each of the electrodes101acts as a touch electrode, which detects a touch position, according to a touch scan signal applied from the touch IC300.

The plurality of electrodes101are divided into a first group110and a second group120, and may be divided in a gate line direction or a data line direction. The first group110includes a second adjacent electrode unit121, and the second group120includes a first adjacent electrode unit111.

Here, the first adjacent electrode unit111is defined as an electrode string that is formed in an area of the second group120adjacent to the first group110, and the number of electrodes of the first adjacent electrode unit111according to an embodiment of the present invention may be one-tenth to half of the number of electrodes included in the second group120. Alternatively, the first adjacent electrode unit111may be an outermost electrode string of the second group120adjacent to the first group110.

Similarly, the second adjacent electrode unit121is defined as an electrode string that is formed in an area of the first group110adjacent to the second group120, and the number of electrodes of the second adjacent electrode unit121according to an embodiment of the present invention may be one-tenth to half of the number of electrodes included in the first group110. Alternatively, the second adjacent electrode unit121may be an outermost electrode string of the first group110adjacent to the second group120.

A plurality of lines connect the plurality of electrodes101to the display driver IC200, respectively. Therefore, a common voltage and a touch scan signal which are output from the display driver IC200are applied to the plurality of electrodes101through the respective lines.

Subsequently, the display driver IC200applies the common voltage to the plurality of electrodes101, or applies the touch scan signal to the plurality of electrodes101included in each of the two divided groups, according to the driving mode of the panel100.

In other words, during the display driving mode, the display driver IC200applies the common voltage to the plurality of electrodes101. During the touch driving mode, the display driver IC200applies the touch scan signal to the first group110and the first adjacent electrode unit111, and applies the touch scan signal to the second group120and the second adjacent electrode unit121.

For example, during the display driving mode of a first frame, the display driver IC200applies the common voltage to the plurality of electrodes, and during the touch driving mode of the first frame, the display driver IC200applies the touch scan signal to the first group110of the two groups and the first adjacent electrode unit111included in the second group120adjacent to the first group110. During the display driving mode of a second frame, the display driver IC200applies the common voltage to the plurality of electrodes, and during the touch driving mode of the second frame, the display driver IC200applies the touch scan signal to the second group120of the two groups and the second adjacent electrode unit121included in the first group110adjacent to the second group120.

Here, the reason that the display driver IC200simultaneously applies the touch scan signal to the first group110and the first adjacent electrode unit111or simultaneously applies the touch scan signal to the second group120and the second adjacent electrode unit121is because in electrodes disposed at a boundary surface between adjacent groups in the two divided groups, when the touch scan signal is applied to the adjacent groups but the electrodes cannot receive the touch scan signal at the same time, there is a possibility that a difference occurs in a touch sensitivity for touch sensing. Therefore, the display drive IC200simultaneously applies the touch scan signal to a group and a boundary surface between the groups and a group adjacent thereto.

Therefore, the touch scan signal that is applied to the first adjacent electrode unit111and the second adjacent electrode unit121may be a touch scan signal for touch sensing, or may be a dummy touch scan signal for reducing a touch sensitivity of an adjacent group, instead of touch sensing.

The display driver IC200, as illustrated inFIG. 3, may drive the plurality of electrodes101as common electrodes or touch electrodes, and include a common voltage generator210, a switching unit220, a sync signal generator230, and a switching control signal generator240.

The common voltage generator210generates the common voltage (Vcom), and applies the common voltage to the switching unit220.

When the driving mode of the panel100is the display driving mode, the common voltage generator210generates the common voltage which is to be applied to the plurality of electrodes so as to output an image, and applies the common voltage to the switching unit220.

The sync signal generator230generates a sync signal indicating the driving mode of the panel100.

For example, when the driving mode of the panel100is the display driving mode, the sync signal generator230generates a sync signal that allows the common voltage generated by the common voltage generator210to be applied to the plurality of electrodes101through the switching unit220, and allows the touch scan signal to be applied to the plurality of electrodes101.

The switching control signal generator240generates a control signal that allows the common voltage generator210to be connected to the plurality of electrodes101, or allows the touch IC300to be connected to the electrodes included in the first group110and the electrodes included in the first adjacent electrode unit111and allows the touch IC300to be connected to the electrodes included in the second group120and the electrodes included in the second adjacent electrode unit121, according to the sync signal of the sync signal generator230.

The switching unit220may be configured with a plurality of first switching units221and a plurality of switching units222, and may apply the common voltage and the touch scan signal to the electrodes101according to the sync signal and the control signal.

Moreover, the switching unit220may simultaneously apply the common voltage to the plurality of electrodes101, or may apply the touch scan signal to the first group110, the first adjacent electrode unit111, the second group120, and the second adjacent electrode unit121, according to the sync signal of the sync signal generator230and the control signal of the switching control signal generator240.

Here, as illustrated inFIG. 3, the plurality of first switching units221receive the sync signal from the sync signal generator230to connect the plurality of second switching units222to the common voltage generator210or the touch IC300. That is, when the sync signal of the sync signal generator230is a sync signal indicating the display driving mode, the plurality of first switching units221connect the plurality of second switching units222to the common voltage generator210, and when the sync signal of the sync signal generator230is a sync signal indicating the touch driving mode, the plurality of first switching units221connect the plurality of second switching units222to the touch IC300. The plurality of first switching units221may include a 2:1 multiplexer.

The plurality of second switching units222receive the control signal from the switching control signal generator240to connect the plurality of first switching units221to the plurality of electrodes or to connect the plurality of first switching units221to the electrodes included in the first group110, the electrodes included in the first adjacent electrode unit111, the electrodes included in the second group120, and the electrodes included in the second adjacent electrode unit121. That is, when the control signal of the switching control signal generator240is a control signal based on the sync signal indicating the display driving mode, the plurality of second switching units222connect the plurality of first switching units221to the plurality of electrodes, and when the control signal of the switching control signal generator240is a control signal based on the sync signal indicating the touch driving mode, the plurality of second switching units222connect the plurality of first switching units221to the first group110and the first adjacent electrode unit111during the first frame, and connect the plurality of first switching units221to the second group120and the second adjacent electrode unit121during the second frame.

For example, as illustrated inFIG. 3, when the control signal of the switching control signal generator240is a control signal based on the sync signal indicating the display driving mode, during the display driving mode, a second switching unit A is connected to electrodes a1 and a2, a second switching unit B is connected to electrodes b1 and b2, a second switching unit C is connected to electrodes c1 and c2, a second switching unit D is connected to electrodes d1 and d2, a second switching unit E is connected to electrodes e1 and e2, and a second switching unit F is connected to electrodes f1 and f2.

For example, when the control signal of the switching control signal generator240is a control signal based on the sync signal indicating the touch driving mode, during the touch driving mode of the first frame, the second switching unit A is connected to the electrodes a1 and a2, the second switching unit B is connected to the electrode b1, the second switching unit C is connected to the electrode c1, the second switching unit D is connected to the electrodes d1 and d2, the second switching unit E is connected to the electrode e1, and the second switching unit F is connected to the electrode f1, and during the touch driving mode of the second frame, the second switching unit A is connected to the electrode a2, the second switching unit B is connected to the electrode b2, the second switching unit C is connected to the electrodes c1 and c2, the second switching unit D is connected to the electrode d2, the second switching unit E is connected to the electrode e2, and the second switching unit F is connected to the electrodes f1 and f2.

Referring again toFIG. 2, the touch IC300applies the touch scan signal to the plurality of electrodes101through the display driver IC200, and then senses a capacitance change of each of the electrodes101to determine whether each electrode is touched.

For example, the touch IC300according to an embodiment of the present invention may include a touch scan signal generator that generates the touch scan signal which is to be supplied to the plurality of electrodes of the panel100for touch sensing. The touch scan signal may be a touch driving voltage, which may have a value higher than the common voltage applied to the plurality of electrodes of the panel100for display driving. In this case, the touch driving voltage may have a voltage corresponding to the common voltage as a low-level voltage, and have a voltage higher than the common voltage as a high-level voltage.

Moreover, the touch IC300according to an embodiment of the present invention may include a touch sensing unit that receives a plurality of touch sensing signals from the respective electrodes101, and calculates touch coordinates by using the touch sensing signals to sense a user's touch. Here, the calculated touch coordinates are transferred to a system unit of the display device, and are used to detect a touch position of the user in the panel100.

Hereinafter, a display device with integrated touch screen according to another embodiment of the present invention will be described in detail with reference toFIGS. 4 and 5.

FIG. 4illustrates an embodiment of an adjacent electrode unit different from the adjacent electrode unit according to an embodiment of the present invention, andFIG. 5illustrates an embodiment of an adjacent electrode unit different from the adjacent electrode unit according to an embodiment of the present invention.

In describing the embodiment ofFIG. 4and the embodiment ofFIG. 5, the elements other than a display driver panel100have been described in detail with reference toFIGS. 2 and 3, and thus, their detailed descriptions are not provided.

A first adjacent electrode unit111of the display device with integrated touch screen according to another embodiment of the present invention, as illustrated inFIG. 4, is defined as an electrode string that is formed in an area of a second group120adjacent to a first group110, and the number of electrodes of the first adjacent electrode unit111according to another embodiment of the present invention may be one-tenth to half of the number of electrodes included in the second group120. Alternatively, the first adjacent electrode unit111may be an outermost electrode string of the second group120adjacent to the first group110and an electrode string that is adjacent to the outermost electrode string in a second group direction.

Similarly, a second adjacent electrode unit121is defined as an electrode string that is formed in an area of the first group110adjacent to the second group120, and the number of electrodes of the second adjacent electrode unit121according to an embodiment of the present invention may be one-tenth to half of the number of electrodes included in the first group110. Alternatively, the second adjacent electrode unit111may be an outermost electrode string of the first group110adjacent to the second group120and an electrode string that is adjacent to the outermost electrode string in a first group direction.

Subsequently, as illustrated inFIG. 5, the electrode groups110and120of the display device with integrated touch screen according to another embodiment of the present invention may be electrode groups that are divided in a data line direction.

A display driver IC200according to another embodiment of the present invention applies the common voltage to the plurality of electrodes101, or applies the touch scan signal to the two groups110and120that are divided in the data line direction, according to the driving mode of the panel100.

In other words, during the display driving mode, the display driver IC200applies the common voltage to the plurality of electrodes101, and during the touch driving mode, the display driver IC200applies the touch scan signal to the first group110, the first adjacent electrode unit111, the second group120, and the second adjacent electrode unit121.

Here, the first adjacent electrode unit111may be the outermost electrode string of the second group120adjacent to the first group110, or may be the outermost electrode string of the second group120and an electrode string that is adjacent to the outermost electrode string in a second group direction. Also, the second adjacent electrode unit121may be the outermost electrode string of the first group110adjacent to the second group120, or may be the outermost electrode string of the first group110and an electrode string that is adjacent to the outermost electrode string in the first group direction.

For example, during the display driving mode of a first frame, the display driver IC200applies the common voltage to the plurality of electrodes, and during the touch driving mode of the first frame, the display driver IC200applies the touch scan signal to the first group110of the two groups and the first adjacent electrode unit111included in the second group120adjacent to the first group110. During the display driving mode of a second frame, the display driver IC200applies the common voltage to the plurality of electrodes, and during the touch driving mode of the second frame, the display driver IC200applies the touch scan signal to the second group110of the two groups and the second adjacent electrode unit121included in the first group110adjacent to the second group120.

Hereinafter, a method of driving the above-described display device with integrated touch screen will be described in detail with reference toFIGS. 2, 3 and 6.

FIG. 6is a timing chart showing signals during a display period and a touch sensing period based on one vertical sync signal, in a display device with integrated touch screen according to various embodiments of the present invention.

Referring again toFIGS. 2 and 3, the display device with integrated touch screen according to an embodiment of the present invention includes the panel that includes the plurality of electrodes which are divided into the two groups, the display driver IC that applies the common voltage or the touch scan signal to the plurality of electrodes, and the touch IC that generates the touch scan signal and applies the touch scan signal to the display driver IC. In particular, the two groups may be groups that are divided in the data line direction.

First, the display device performs an operation which, during the display driving mode of the first frame, applies the common voltage to the plurality of electrodes, and during the touch driving mode of the first frame, applies the touch scan signal to the first group110of the two groups and the first adjacent electrode unit111included in the second group120adjacent to the first group110. Here, the first adjacent electrode unit111is defined as an electrode string that is formed in an area of a second group120adjacent to a first group110, and the number of electrodes of the first adjacent electrode unit111according to an embodiment of the present invention may be one-tenth to half of the number of electrodes included in the second group120. Alternatively, the first adjacent electrode unit111may be an outermost electrode string of the second group120adjacent to the first group110, or the first adjacent electrode unit111may be an outermost electrode string of the second group120adjacent to the first group110and an electrode string that is adjacent to the outermost electrode string in the second group direction.

Subsequently, the display device performs an operation which, during the display driving mode of a second frame, applies the common voltage to the plurality of electrodes, and during the touch driving mode of the second frame, applies the touch scan signal to the second group110of the two groups and the second adjacent electrode unit121included in the first group110adjacent to the second group120. Here, the second adjacent electrode unit121is defined as an electrode string that is formed in an area of the first group110adjacent to the second group120, and the number of electrodes of the second adjacent electrode unit121according to an embodiment of the present invention may be one-tenth to half of the number of electrodes included in the first group110. Alternatively, the second adjacent electrode unit121may be an outermost electrode string of the first group110adjacent to the second group120, or the second adjacent electrode unit111may be an outermost electrode string of the first group110adjacent to the second group120and an electrode string that is adjacent to the outermost electrode string in the first group direction.

To summarize the display device with integrated touch screen according to an embodiment of the present invention with reference toFIG. 6, the display driving period according to the present invention is relatively longer, and the touch sensing period according to the present invention is relatively shorter, in comparison with general display devices with integrated touch screen.

Moreover, during the touch sensing period of the first frame, the display device with integrated touch screen according to an embodiment of the present invention applies the touch scan signal to all the electrodes included in the first group, and applies the touch scan signal to only some electrodes which are included in the second group and are adjacent to the first group. Furthermore, during the touch sensing period of the second frame, the display device with integrated touch screen according to an embodiment of the present invention applies the touch scan signal to all the electrodes included in the second group, and applies the touch scan signal to only some electrodes which are included in the first group and are adjacent to the second group.

Here, the reason that the display device with integrated touch screen according to an embodiment of the present invention applies the touch scan signal to all the electrodes included in the first group and some electrodes which are included in the second group and are adjacent to the first group, or applies the touch scan signal to all the electrodes included in the second group and some electrodes which are included in the first group and are adjacent to the second group is because in electrodes disposed at a boundary surface between adjacent groups in the two divided groups, when the touch scan signal is applied to the adjacent groups but the electrodes cannot receive the touch scan signal at the same time, there is a possibility that a difference occurs in a touch sensitivity for touch sensing.

According to various embodiments of the present invention, the display device with integrated touch screen can stably secure a display driving time when driving a high-resolution panel.

Moreover, according to various embodiments of the present invention, the display device with integrated touch screen can minimize a possibility of an error which is caused by a touch sensitivity and occurs at the boundaries of the touch electrodes which are divided into the groups.