CROSS REFERENCE TO RELATED APPLICATION

This application claims priority from Korean Patent Application No. 10-2018-0068330, filed on Jun. 14, 2018, which is hereby incorporated by reference for all purposes as if fully set forth herein.

BACKGROUND

1. Technical Field

The present disclosure relates to a touch display device, a touch sensing circuit, and a driving method.

2. Description of the Related Art

With the development of the information society, various demands for touch display devices to display images have increased. Recently, various display devices, such as liquid crystal display devices, plasma display devices, organic light emitting display devices, or the like are being utilized.

Among the display devices, there is a touch display device which provides a touch-based input scheme such that a user can easily and intuitively input information or commands beyond a typical input scheme, such as using a button, a keyboard, a mouse, or the like.

In related art display devices, a large number of touch electrodes that perform touch sensing are disposed, and the large number of touch electrodes are sensed to determine touch coordinates or the presence or absence of touch by a user.

Therefore, there is a problem in that all the large number of touch electrodes are required to be sensed to determine touch coordinates or the presence or absence of touch in all areas, and it takes a long time for the same.

SUMMARY

Accordingly, embodiments of the present disclosure are directed to a touch display device, a touch sensing circuit, and a driving method that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.

An aspect of the present disclosure is to provide a touch display device, a touch sensing circuit, and a driving method, by which a touch sensing time can be significantly reduced.

Another aspect of the present disclosure is to provide the touch display device, the touch sensing circuit, and the driving method, by which excellent touch sensitivity and a fast touch sensing speed are allowed.

Still another aspect of the present disclosure is to provide the touch display device, the touch sensing circuit, and the driving method, by which influence between display driving and touch driving can be reduced.

Still another aspect of the present disclosure is to provide the touch display device, the touch sensing circuit, and the driving method, by which, even though display and touch sensing are concurrently performed, touch sensing is prevented from being influenced by display driving, so that touch sensitivity can be improved.

Still another aspect of the present disclosure is to provide the touch display device, the touch sensing circuit, and the driving method, by which, when display and touch sensing are concurrently performed, undesired voltage fluctuation in touch electrodes due to voltage fluctuation of a display driving electrode, such as a data line, is prevented from occurring, so that touch sensitivity can be improved.

Additional features and aspects will be set forth in the description that follows, and in part will be apparent from the description, or may be learned by practice of the inventive concepts provided herein. Other features and aspects of the inventive concepts may be realized and attained by the structure particularly pointed out in the written description, or derivable therefrom, and the claims hereof as well as the appended drawings.

In an aspect, embodiments of the present disclosure may provide a touch display device including multiple touch electrodes and a touch sensing circuit configured to sense the multiple touch electrodes.

The touch sensing circuit may group the multiple touch electrodes into multiple touch electrode groups, and concurrently sense each of the multiple touch electrode groups.

The touch sensing circuit may perform group differential sensing for the multiple touch electrode groups.

The multiple touch electrodes may be arranged in a matrix type.

Touch electrodes arranged in each touch electrode column may include g number of touch electrode groups, each of which includes k number of touch electrodes. Here, k and g may be natural numbers of 2 or more.

During a j-th frame for displaying an image, the touch sensing circuit may: select, as sensing touch electrodes, the k number of touch electrodes included in a first touch electrode group from among the g number of touch electrode groups; select, as reference touch electrodes, the k number of touch electrodes included in a second touch electrode group that is different from the first touch electrode group from among the g number of touch electrode groups; and match the k number of the touch electrodes included in the first touch electrode group, which are selected as a sensing touch electrode group, and the k number of touch electrodes included in the second touch electrode group, which are selected as a reference touch electrode group, so as to perform group differential sensing.

The touch sensing circuit may comprise as many differential sensing circuits as the number of touch electrodes included in each of the g number of touch electrode groups.

The differential sensing circuit may have a positive input terminal and a negative input terminal.

The positive input terminal of the differential sensing circuit may be electrically connected to one among the k number of touch electrodes included in the first touch electrode group, which are selected as sensing touch electrodes. The negative input terminal of the differential sensing circuit may be electrically connected to one among the k number of touch electrodes included in the second touch electrode group, which are selected as reference touch electrodes.

The differential sensing circuit may output or store a voltage difference between a voltage applied to the positive input terminal and a voltage applied to the negative input terminal.

The touch sensing circuit may include the k number of multiplexers that selects a sensing channel and a reference channel from among the g number of channels, and the k number of differential sensing circuits including a positive input terminal, a negative input terminal, and an output terminal.

Each of the k number of multiplexers may include the g number of channels and two channel connection terminals (a sensing channel connection terminal and a reference channel connection terminal).

Each of the k number of multiplexers may select the sensing channel and the reference channel from among the g number of channels, and may connect the selected channels to two channel connection terminals (the sensing channel connection terminal and the reference channel connection terminal).

The k number of touch electrodes included in the first touch electrode group are the sensing touch electrodes and correspond to sensing channels selected from the respective k number of multiplexers, and the k number of touch electrodes included in the second touch electrode group are the reference touch electrodes and correspond to reference channels selected from the respective k number of multiplexers.

Any i-th multiplexer among the k number of multiplexers may be connected to an i-th differential sensing circuit among the k number of differential sensing circuits. Here, i may be one of numbers from 1 to k.

The i-th multiplexer may select a sensing channel and a reference channel among the g number of channels corresponding to i-th touch electrodes of the respective g number of touch electrode groups, and may connect the sensing channel and the reference channel to a sensing channel connection terminal and a reference channel connection terminal, respectively.

In the i-th multiplexer, the sensing channel connection terminal may be electrically connected to a positive input terminal of an i-th differential sensing circuit, and the reference channel connection terminal maybe connected to a negative input terminal of the i-th differential sensing circuit.

A first preamplifier electrically connected between the sensing channel connection terminal of the i-th multiplexer and the positive input terminal of the i-th differential sensing circuit may be included, and a second preamplifier electrically connected between the reference channel connection terminal of the i-th multiplexer and the negative input terminal of the i-th differential sensing circuit may be included.

A first integrator may be connected between the first preamplifier and the positive input terminal of the i-th differential sensing circuit, and a second integrator may be connected between the second preamplifier and the negative input terminal of the i-th differential sensing circuit.

An integrator may be connected to an output terminal of the i-th differential sensing circuit.

The first touch electrode group mentioned above may be positioned closer to the touch sensing circuit, compared to the second touch electrode group.

On the contrary, the second touch electrode group mentioned above may be positioned closer to the touch sensing circuit, compared to the first touch electrode group.

The touch sensing circuit may operate by alternating group differential sensing directions for each frame.

Accordingly, during a frame other than the j-th frame, the touch sensing circuit may: select, as sensing touch electrodes, the k number of touch electrodes included in the second touch electrode group from among the g number of touch electrode groups; select, as reference touch electrodes, the k number of touch electrodes included in the first touch electrode group from among the g number of touch electrode groups; and match the k number of the touch electrodes included in the second touch electrode group and the k number of touch electrodes included in the first touch electrode group, so as to concurrently perform group differential sensing.

Touch electrodes arranged in each touch electrode column may further include one additional touch electrode group including the d number of touch electrodes, in addition to the g number of touch electrode groups, each of which includes the k number of touch electrodes. Here, d is a natural number equal to or larger than 1 and smaller than k.

The touch sensing circuit may select, as sensing touch electrodes, the k number of touch electrodes including the d number of touch electrodes and the (k−d) number of touch electrodes arranged on the d number of touch electrodes, may select, as reference touch electrodes, the k number of touch electrodes arranged on the (k−d) number of touch electrodes, and may differentially sense the k number of touch electrodes selected as the sensing touch electrodes and the k number of touch electrodes selected as the reference touch electrodes.

The touch display device may include a display panel in which multiple data lines and multiple gate lines are arranged. In this case, the multiple touch electrodes may be embedded in the display panel.

The touch display device may perform display and touch sensing independently.

For example, the touch display device may concurrently perform display and touch sensing.

To this end, when a touch electrode driving signal of a pulse modulation signal type, in which voltage swings to the k number of touch electrodes included in the first touch electrode group and the k number of touch electrodes included in the second touch electrode group, is applied, a data signal for image display may be applied to the data lines.

Each touch electrode column may be disposed so as to overlap with the data lines.

In another aspect, a touch sensing circuit of embodiments of the present disclosure may include: the k number of multiplexers that select, during a j-th frame, as sensing touch electrodes, the k number of touch electrodes (k≥2) included in a first touch electrode group among the g number of touch electrode groups (g≥2) in which multiple touch electrodes are grouped, and selects, as reference touch electrodes, the k number of touch electrodes included in a second touch electrode group other than the first touch electrode group from among the g number of touch electrode groups; and a differential sensing circuit that matches the k number of touch electrodes included in the first touch electrode group and the k number of touch electrodes included in the second touch electrode group so as to perform differential sensing.

The k number of touch electrodes included in the first touch electrode group may be divided and connected to the k number of multiplexers, and the k number of multiplexers may select, as sensing touch electrodes, all the k number of touch electrodes included in the first touch electrode group so as to connect the selected k number of touch electrodes to positive input terminals of the k number of differential sensing circuits.

The k number of touch electrodes included in the second touch electrode group may be divided and connected to the k number of multiplexers, and the k number of multiplexers may select, as reference touch electrodes, all the k number of touch electrodes included in the second touch electrode group so as to connect the selected k number of touch electrodes to negative input terminals of the k number of differential sensing circuits.

During a frame other than the j-th frame: the k number of multiplexers may select, as sensing touch electrodes, the k number of touch electrodes included in the second touch electrode group from among the g number of touch electrode groups, and may select, as reference touch electrodes, the k number of touch electrodes included in the first touch electrode group from among the g number of touch electrode groups; and the k number of differential sensing circuits may match the k number of the touch electrodes included in the second touch electrode group and the k number of touch electrodes included in the first touch electrode group, so as to concurrently perform group differential sensing.

Each of the k number of differential sensing circuits may be a sample-and-hold circuit or a differential amplifier.

In still another aspect, embodiments of the present disclosure relate to a method of driving a touch display device that includes multiple touch electrodes and a touch sensing circuit configured to sense the multiple touch electrodes, the method including: during a j-th frame, selecting, as sensing touch electrodes, the k number of touch electrodes (k≥2) included in a first touch electrode group among the g number of touch electrode groups (g≥2) in which multiple touch electrodes are grouped, and selecting, as reference touch electrodes, the k number of touch electrodes included in a second touch electrode group other than the first touch electrode group from among the g number of touch electrode groups; and matching the k number of touch electrodes included in the first touch electrode group, i.e., a sensing touch electrode group, and the k number of touch electrodes included in the second touch electrode group, i.e., a reference touch electrode group, so as to perform differential sensing.

The method may further include: during the j-th frame, after performing of the differential sensing, during another frame other than the j-th frame, selecting, as sensing touch electrodes, the k number of touch electrodes included in the second touch electrode group from among the g number of touch electrode groups, and selecting, as reference touch electrodes, the k number of touch electrodes included in the first touch electrode group from among the g number of touch electrode groups; and matching the k number of the touch electrodes included in the second touch electrode group, i.e., the sensing touch electrode group, and the k number of touch electrodes included in the first touch electrode group, i.e., the reference touch electrode group, so as to perform group differential sensing.

The multiple touch electrodes may be embedded in the display panel in which multiple data lines and multiple gate lines are arranged.

When a touch electrode driving signal is applied to the k number of touch electrodes included in the first touch electrode group and the k number of touch electrodes included in the second touch electrode group, a data signal for image display may be applied to the data lines.

Embodiments of the present disclosure described above may provide a touch display device, a touch sensing circuit, and a driving method, by which a touch sensing time can be significantly reduced.

Embodiments of the present disclosure may provide the touch display device, the touch sensing circuit, and the driving method, by which excellent touch sensitivity and a fast touch sensing speed are allowed.

Embodiments of the present disclosure may provide the touch display device, the touch sensing circuit, and the driving method, by which influence between display driving and touch driving can be reduced.

Embodiments of the present disclosure may provide the touch display device, the touch sensing circuit, and the driving method, by which, even though display and touch sensing are concurrently performed, touch sensing is prevented from being influenced by display driving, so that touch sensitivity can be improved.

Embodiments of the present disclosure may provide the touch display device, the touch sensing circuit, and the driving method, by which, when display and touch sensing are concurrently performed, undesired voltage fluctuation in touch electrodes due to voltage fluctuation of a display driving electrode, such as a data line, is prevented from occurring, so that touch sensitivity can be improved.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the inventive concepts as claimed.

