TWI889736B - Touch sensing device - Google Patents

Abstract

The present disclosure relates to a touch sensing technology for sensing noise in order to avoid the noise, which allows previously prevent the possibility that a frequency of a driving signal is changed in a predetermined order or at random by changing the frequency of the driving signal in conformity with a frequency least affected by the noise.

Description

touch sensing device

This embodiment relates to touch sensing technology for detecting noise.

Touch sensing technology is used to detect external objects approaching or touching a touch panel. The touch panel is placed on a flat surface at the same location as the display panel. This allows users to input user manipulation signals using the touch panel while viewing images on the display panel. This method of generating user manipulation signals offers significantly greater intuitiveness than other existing methods of inputting user manipulation signals, such as mouse input or keyboard input.

Due to these advantages, touch sensing technology is being applied to various electronic devices, including display panels. A touch sensing device supplies a drive signal to a drive electrode within the touch panel and receives a response signal from a sense electrode, thereby detecting the touch or proximity of an external object to the touch panel. The touch panel generates capacitance between the drive electrode and the sense electrode, and changes in capacitance indicate the touch or proximity of an external object.

On the other hand, touch panels may contain noise. When an external object touches the touch panel, the noise may be transmitted through the external object, which may cause malfunction in the touch panel.

To detect noise, the conventional approach is to determine whether the frequency of the noise contained in the response signal is similar to that of the original signal. If so, the frequency of the drive signal is changed. If the response signal fluctuates by more than a predetermined value relative to a reference value, it is determined that the noise frequency is similar to the response signal frequency. The reference value can be data obtained without the presence of an external object, or without noise.

However, the above-mentioned conventional method can detect noise having the same frequency as the driving signal, but cannot detect various types of noise such as harmonic noise.

In this regard, the present embodiment provides a technique for effectively sensing various types of noise that occur in touch sensing.

Against this backdrop, the present embodiment aims to provide a technique for sensing noise using the average of the differences in maximum raw sensing values between consecutive frames, or using the geometric features of the touch area based on the number of touches or proximity areas.

To this end, in one aspect, the present invention provides a touch sensing device comprising: a driving circuit configured to drive a touch electrode using a driving signal; a sensing circuit configured to generate a sensing value for the touch electrode; and a noise determination circuit configured to determine that noise is contained in touch sensing of one or more touch areas segmented according to the sensing value when a distance between two adjacent touch areas segmented according to the sensing value is equal to or less than a predetermined distance and when a width of one of the two touch areas is equal to or less than a predetermined width.

The sensed value may be generated in the form of a matrix including a plurality of nodes, and when the two touch areas are formed with a node disposed therebetween, the noise determination circuit may determine that the distance is equal to or less than the predetermined distance.

When only the number of touch areas between frames is different, the noise determination circuit can determine whether noise is included in touch sensing based on the distance between two adjacent touch areas or the width of the touch areas.

The noise determination circuit can determine whether noise is included in touch sensing based on the distance between two adjacent touch areas or the width of the touch area after a predetermined frame from the beginning.

When the noise determination circuit determines that noise is included in touch sensing, the driving circuit may drive the touch electrode using a driving signal having a changed frequency.

When the number of touch areas remains the same between frames, the noise determination circuit can be configured to extract the maximum value of the sensed value for each frame, calculate the difference between the maximum values between the frames, and determine whether noise is included in the touch sensing based on a representative value of the difference values calculated for multiple frames.

The representative value may be an average value, and when the average value is greater than a threshold value, the noise determination circuit may determine that noise is included in the touch sensing.

In another aspect, the present invention provides a touch sensing device comprising: a driving circuit configured to drive a touch electrode using a driving signal; a sensing circuit configured to generate a sensing value for the touch electrode; and a noise determination circuit configured to determine that noise is included in the touch sensing of one or more touch areas segmented according to the sensing value when the width of one of the one or more touch areas segmented according to the sensing value is equal to or less than a predetermined width.

The sensed value may be generated in the form of a matrix including a plurality of nodes, and when the width of a touch area is equal to or less than the width of a node, the noise determination circuit may determine that noise is included in the touch sensing.

The noise determination circuit can determine whether noise is included in touch sensing based on the width of a touch area after a predetermined frame from the beginning.

When the noise determination circuit determines that noise is included in the touch sensing, the driving circuit may drive the touch electrode using a driving signal with a changed frequency.

When only the number of touch areas differs between frames, the noise determination circuit can determine whether noise is included in touch sensing based on the width of a touch area.

When the number of touch areas remains the same between frames, the noise determination circuit can be configured to extract the maximum value of the sensed value for each frame, calculate the difference between the maximum values between the frames, and determine whether noise is included in the touch sensing based on a representative value of the difference values calculated for multiple frames.

The representative value may be an average value, and when the average value is greater than a threshold value, the noise determination circuit may determine that noise is included in the touch sensing.

In yet another aspect, the present invention provides a touch sensing device comprising: a drive circuit configured to drive a touch electrode using a drive signal; a sensing circuit configured to generate a sensed value for the touch electrode for each frame; and a noise determination circuit configured to extract a maximum value of the sensed value for each frame, calculate the difference between the maximum values between frames, and determine whether noise is included in the touch sensing based on a representative value of the differences calculated for multiple frames.

As described above, according to this embodiment, various types of noise such as harmonic noise can be sensed, thereby reducing false recognition of touch.

100: Display device

110: Panel

120: Data drive

130: Gate drive device

140: Touch sensor device

200: Touch Sensing System

310: Drive circuit

320: Sensing circuit

330: Noise determination circuit

340: Control circuit

350: Storage circuit

401: Raw sensor value distribution

402: Raw sensor value distribution

502: Raw sensor value distribution

CS: Control signal

D: distance

DL: Data Line

GL: Gate Line

H1: Width

H2: Width

I: First contact area

I-1: 1st Touch Area

I-2: 1st-2nd touch zone

OBJ: External Object

P: Pixels

S702: Step

S704: Step

S706: Step

S708-1: Steps

S708-2: Steps

S710-1: Step

S710-2: Step

S712-1: Step

S712-2: Steps

SL: Sensing line

SRX: Response signal

STX: drive signal

TE: Touch electrode

TSEN_RAW: Raw sensor value

X: X-axis

Y:Y axis

The above and other aspects, features, and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG1 is a diagram illustrating the structure of a display device according to an embodiment; FIG2 is a diagram schematically illustrating a touch sensing system according to an embodiment; FIG3 is a diagram illustrating the structure of a touch sensing device according to an embodiment; and FIG4 is a diagram illustrating the maximum distance between frames according to an embodiment. FIG5 is a diagram illustrating a noise sensing method using the difference between the original sensing values; FIG5 is a display showing a first example of a noise sensing method using the geometric features of a touch area according to an embodiment; FIG6 is a display showing a second example of a noise sensing method using the geometric features of a touch area according to an embodiment; and FIG7 is a flow chart showing an operation of a touch sensing device sensing noise according to an embodiment.

FIG1 is a diagram showing the structure of a display device according to an embodiment.

Referring to FIG1 , a display device 100 includes a panel 110 , a data driver 120 , a gate driver 130 , and a touch sensor 140 .

A plurality of data lines DL connected to the data driver 120 may be formed on the panel 110, and a plurality of gate lines GL connected to the gate driver 130 may be formed on the panel 110. Furthermore, a plurality of pixels P may be defined at points where the plurality of data lines DL and the plurality of gate lines GL intersect in the panel 110.

A transistor may be formed in each pixel P, the transistor having a first electrode (e.g., a source electrode or a drain electrode) connected to the data line DL, a gate electrode connected to the gate line GL, and a second electrode (e.g., a drain electrode or a source electrode) connected to the display electrode.

In addition, a plurality of touch electrodes TE may be further provided in the panel 110 in a manner spaced apart from each other. One pixel P or a plurality of pixels P may be located in the region where the touch electrodes TE are located.

The panel 110 may include a display panel and a touch panel (e.g., a touch screen panel (TSP)), wherein the display panel and the touch panel may share some components. For example, the touch electrode TE may be a component of the display panel (e.g., a common electrode for applying a common voltage) and may also be a component of the touch panel (e.g., a touch electrode for detecting touch). Although the panel 110 is referred to as an "integrated panel" because some components of the display panel and the touch panel are shared, the present invention is not limited thereto. In-cell panels are known as panels that share some components of the display panel and the touch panel, but this is merely an example of the panel 110, and the panels to which the present invention is applicable are not limited to in-cell panels.

The data driver 120 supplies data signals to the data lines DL to display images on each pixel P in the panel 110.

The data drive device 120 may include at least one data drive integrated circuit, and the at least one data drive integrated circuit may be connected to the bonding pads of the panel 110 via a tape automated bonding (TAB) type or a chip-on-glass (COG) type, or may be formed directly in the panel 110. In some cases, the data drive integrated circuit may be formed to be integrated on the panel 110. Alternatively, the data drive device 120 may be implemented via a chip-on-film (COF) type.

The gate driver 130 sequentially supplies a scanning signal to the gate line GL to turn on or off the transistor in each pixel P.

Depending on the driving method, the gate driver 130 may be located on only one side of the panel 110 as shown in the figure, or two separate gate drivers may be located on both sides of the panel 110.

In addition, the gate driver device 130 may include at least one gate driver integrated circuit, and the at least one gate driver integrated circuit may be connected to a bonding pad of the panel 110 using a tape automated bonding (TAB) type or a chip-on-glass (COG) type, or may be formed directly on the panel 110 using a gate-in-panel (GIP) type. In some cases, the gate driver integrated circuit may be formed to be integrated on the panel 110. In addition, the gate driver device 130 may be implemented using a chip-on-film (COF) type.

The touch sensing device 140 applies a driving signal to all or part of the plurality of touch electrodes TE connected to the sensing line SL.

As shown in the figure, the touch sensing device 140 can be provided as a separate component from the data driver 120 and the gate driver 130 and external to the data driver 120 and the gate driver 130. However, in practice, the touch sensing device 140 can be implemented as an internal component of another independent driver integrated circuit that includes at least one of the data driver 120 and the gate driver 130; or can be implemented as an internal component of the data driver 120 or the gate driver 130.

Therefore, the operation of the touch sensing device 140 applying a drive signal to all or part of the multiple touch electrodes TE can be understood as the operation of a separate driver integrated circuit including the touch sensing device 140 applying a drive signal to all or part of the multiple touch electrodes TE. Alternatively, depending on the design, this operation can be considered as the operation of the data driver device 120 or gate driver device 130 including the touch sensing device 140 applying a drive signal to all or part of the multiple touch electrodes TE.

The touch sensing device 140 is not limited to a specific implementation and design and may be implemented as a separate component, or may be implemented as a component provided inside or outside another component, as long as the same or similar functions as those described in this specification can be achieved.

In addition, although a single touch sensing device 140 is shown in the figure as being located in the display device 100, the display device 100 may include two or more touch sensing devices 140.

On the other hand, sensing lines SL connected to each touch electrode TE are required so that the touch sensing device 140 can apply a driving signal to all or part of the multiple touch electrodes TE. Therefore, the sensing lines SL can be formed along a first direction (e.g., vertical direction) or a second direction (e.g., horizontal direction) to connect to each touch electrode TE, thereby transmitting a driving signal to these touch electrodes TE.

On the other hand, the display device 100 may use a capacitive touch method that recognizes the proximity or touch of an object by sensing a change in capacitance through a touch electrode TE.

Capacitive touch methods can be categorized into, for example, mutual capacitance touch methods and self-capacitance touch methods.

In the mutual capacitance touch method, a type of capacitive touch method, a drive signal is applied to a touch electrode (e.g., a Tx electrode), and another touch electrode (e.g., an Rx electrode) coupled to the Tx electrode is sensed. In the mutual capacitance touch method, the value sensed at the Rx electrode changes in response to the approach or touch of an object, such as a finger or pen. The sensed value at the Rx electrode is used to detect the presence or absence of a touch, the touch coordinates, and other information.

In the self-capacitive touch method, another capacitive touch method, a drive signal is applied to a touch electrode TE, and the corresponding touch electrode TE is then sensed. In the self-capacitive touch method, the value sensed at the corresponding touch electrode TE changes in response to the approach or touch of an object such as a finger or pen. The sensed value is used to detect the presence or absence of a touch, the touch coordinates, etc. In the self-capacitive touch method, since the touch electrode TE that applies the drive signal and the touch electrode TE that senses the value are the same, there is no distinction between the Tx electrode and the Rx electrode.

The display device 100 can use either of the two capacitive touch methods described above (mutual capacitance touch method and self-capacitance touch method). However, in this specification, for ease of explanation, it will be assumed that the self-capacitance touch method is used.

Alternatively, the display device 100 may drive the touch electrodes TE separately for the display segment and the touch segment. For example, the touch sensing device 140 of the display device 100 may not apply a driving signal to all or part of the touch electrodes TE during the segment in which the data signal is supplied.

In addition, the display device 100 can drive the touch electrode TE without separating the display segment and the touch segment. For example, the touch sensor device 140 of the display device 100 may not apply a driving signal to all or part of the touch electrode TE during the segment where the data signal is supplied.

FIG2 is a diagram schematically illustrating a touch sensing system according to an embodiment.

2 , the touch sensing system 200 may include a panel 110 and a touch sensing device 140.

The panel 110 may have a plurality of touch electrodes TE configured thereon.

The touch sensing device 140 can supply a driving signal STX to the touch electrode TE. The driving signal STX can be a voltage or current signal, and the voltage driving signal STX can be defined as a "driving voltage." The driving signal can include a driving cycle including a first time period and a second time period.

The touch sensing device 140 can receive a response signal SRX to the driving signal STX from the touch electrode TE and demodulate the response signal SRX to thereby sense the touch or proximity of the object 10 relative to the panel 110. The response signal SRX can be a current or voltage signal.

FIG3 is a diagram showing the structure of a touch sensing device according to an embodiment.

3 , the touch sensing device 140 may include a driving circuit 310 , a sensing circuit 320 , a noise determination circuit 330 , a control circuit 340 , and a storage circuit 350 .

The driving circuit 310 can supply a driving signal STX having a certain frequency to the touch electrode. The driving circuit 310 can drive the touch electrode using the driving signal STX having a different frequency. For example, the driving circuit 310 can receive a driving signal STX having a changed frequency from the control circuit 340 and can drive the touch electrode using the changed frequency.

The sensing circuit 320 can receive a response signal SRX from the touch electrode in response to the drive signal STX. The sensing circuit 320 can receive a response signal SRX having a different frequency in response to the drive signal STX. For example, if the drive circuit 310 drives the touch electrode using a changed frequency, the sensing circuit 320 can receive a response signal SRX having a changed frequency that is different from the previous frequency.

The sensing circuit 320 can detect the touch or proximity of an external object relative to the panel based on the response signal SRX. The sensing circuit 320 can demodulate the response signal SRX to generate touch sensing data. The sensing circuit 320 can then send the touch sensing data to the noise determination circuit 330.

Touch sensing data may include raw sensing values TSEN_RAW generated by demodulating the response signal SRX. For example, the raw sensing value TSEN_RAW may be the time-integrated value of the current or voltage of the response signal SRX. The raw sensing value TSEN_RAW can be used to determine whether an object has touched the touch panel or to generate touch coordinates. For example, if the raw sensing value TSEN_RAW is greater than or less than a reference value, it can be determined that an external object has touched the touch panel.

Sensing circuit 320 can generate a raw sensed value TSEN_RAW for the touch electrode. If the touch electrode is sensed, a raw sensed value TSEN_RAW can be generated for each touch electrode. The raw sensed value TSEN_RAW may be generated based on the configuration of the touch electrodes on the panel. When an external object touches or approaches a touch electrode, capacitance may change, and the raw sensed value TSEN_RAW may change accordingly. Changes in the raw sensed value TSEN_RAW may occur at multiple touch electrodes surrounding the touch or approach point. The raw sense value TSEN_RAW may increase or decrease in multiple touch electrodes affected by touch or proximity compared to touch electrodes not affected by touch or proximity. An area of the touch panel where the raw sense value TSEN_RAW changes in multiple touch electrodes affected by touch or proximity is referred to as a "touch area."

The sensing circuit 320 may generate raw sensing values in the form of a matrix including a plurality of nodes. Furthermore, the sensing circuit 320 may classify adjacent nodes whose raw sensing values are equal to or greater than a predetermined reference value into one touch area and assign a label to the corresponding touch area.

The touch electrode most affected by touch or proximity (i.e., the touch electrode at the point of touch or proximity) may have the most maximized raw sense value TSEN_RAW (e.g., the maximum value or minimum value). Hereinafter, the touch electrode most affected by touch or proximity may be referred to as a "point touch electrode."

Sensing circuit 320 can generate a raw sensed value TSEN_RAW of the touch electrode for each frame. Sensing circuit 320 can generate TSEN_RAW using either a first method (sensing the touch panel after scanning all lines of the display panel in a frame) or a second method (sensing the touch panel after scanning only a portion of the lines of the display panel in a frame). Sensing circuit 320 can generate TSEN_RAW of the touch electrode for each frame using either the first or second method.

The noise determination circuit 330 can compare the number of touch areas across multiple frames. For example, the noise determination circuit 330 can count the number of touch areas for each of two or more temporally close frames and determine whether the number of touch areas between these frames is the same or different. Here, the two or more temporally close frames can refer to consecutive reproduction frames, such as the current frame and the previous frame, or the current frame and the subsequent frame.

To identify the number of touch areas, the noise determination circuit 330 can use the distribution of changes in the capacitance of the touch electrode (e.g., raw sense value TSEN_RAW). For example, the noise determination circuit 330 can determine that connected raw sense values TSEN_RAW constitute a touch area. If a discontinuity or intermittent point where the raw sense value TSEN_RAW does not occur is detected in a touch area, the noise determination circuit 330 can determine that a new touch area exists based on this fact.

The noise determination circuit 330 can use a representative value of the raw sensing value TSEN_RAW between multiple frames, or can use the geometric features of the touch area based on the comparison results to determine whether noise exists in the touch area.

Specifically, if the number of touch areas remains the same across multiple frames, the noise determination circuit 330 may use the average of the differences in the maximum raw sensed values across the multiple frames as a representative value, and if it is determined that noise exists in the touch area, the control circuit 340 may be controlled to change the frequency of the drive signal.

For example, when the display device drives N frames (N is a natural number of 2 or greater), the noise detection circuit 330 can calculate the number of touch areas in the current frame and the previous frame among the 1st to Nth frames. If the number of touch areas remains the same as a result of the comparison by the noise detection circuit 330, the noise detection circuit 330 can determine that the number of touch areas is the same across multiple frames. There may be one or more touch areas, and the number of touch areas may be the same between the current frame and the previous frame.

Next, the noise detection circuit 330 can calculate the difference between the maximum raw sense values of two consecutive frames. The noise detection circuit 330 can calculate the difference between the maximum raw sense value of the (N-1)th frame and the maximum raw sense value of the Nth frame. Furthermore, the noise detection circuit 330 can calculate the difference between the maximum raw sense value of the (N-2)th frame and the maximum raw sense value of the (N-1)th frame. Using the above method, the noise detection circuit 330 can calculate the difference between the maximum raw sense values of two consecutive frames from the 1st frame to the Nth frame, thereby obtaining N-1 difference values. The noise detection circuit 330 can then obtain the average of these N-1 difference values. Therefore, the noise determination circuit 330 can calculate the average value of the difference in the maximum raw sensed values between frames.

The noise determination circuit 330 may use a threshold value to determine whether noise is present in the touch area based on an average value. If the average value is greater than the threshold value, the noise determination circuit 330 may determine that noise is present. On the other hand, if the average value is not greater than the threshold value, the noise determination circuit 330 may determine that noise is not present.

If it is determined that noise exists, the noise determination circuit 330 may generate a frequency change signal and send the frequency change signal to the control circuit 340 to change the frequency of the driving signal used to drive the touch electrode from a touch section of the current frame or from a subsequent frame.

In addition, if the number of touch areas varies between multiple frames, the noise determination circuit 330 may use geometric characteristics of the touch area and, if it is determined that noise exists in the touch area, may control the control circuit 340 to change the frequency of the driving signal.

For example, when the display device drives N frames (N is a natural number of 2 or greater), the noise detection circuit 330 can calculate the number of touch areas in the current frame and the previous frame among frames 1 to N. If the noise detection circuit 330 compares the number of touch areas and finds that the number of touch areas differs, the noise detection circuit 330 can determine that the number of touch areas differs between the multiple frames. One or more touch areas may exist, and the number of touch areas may differ between the current frame and the previous frame.

The noise detection circuit 330 can then output the geometric characteristics of the touch area for each frame. The noise detection circuit 330 can identify the shape of the touch area, the position of the touch area, and the distance between touch areas as the geometric characteristics of the touch area. For example, the noise detection circuit 330 can calculate the shape, position, and distance of the touch area in the current frame.

The noise determination circuit 330 can use predetermined conditions based on geometric features to determine whether noise exists in the touch area.

For example, if the width or amplitude (horizontal or vertical length) of the touch area in the current frame falls within a predetermined range, the noise determination circuit 330 may determine that noise exists in the touch area. The predetermined range of width or amplitude may be a length corresponding to one or two touch electrodes where a single and independent touch is unlikely to occur.

For example, if the distance (interval) between multiple touch areas in the current frame falls within a predetermined range, the noise determination circuit 330 may determine that noise exists in the touch area. The predetermined distance range may correspond to the length of one or two touch electrodes where single and independent touches are unlikely to occur. The distance may be measured between a point touch electrode and multiple touch areas, or may be measured based on the touch electrodes located at the outermost portion of the touch area.

Additionally, the noise detection circuit 330 can determine noise based on the geometric characteristics of the touch area by considering whether the difference in the maximum raw sensed values across multiple frames is greater than a threshold. The noise detection circuit 330 can compare the difference in the maximum raw sensed values between the current frame and the previous frame with the threshold.

Because touch sensitivity is low, the width or amplitude of the touch can fall within a predetermined range just before a touch or proximity occurs. That is, the width or breadth of the touch area can be as short as the length of one or two touch electrodes. Even if the width or amplitude of the touch area falls within the predetermined range, it may not contain noise just before a touch or proximity occurs. Therefore, noise detection circuit 330 can determine that noise exists in multiple touch areas only if the difference in the maximum raw sensed value across multiple frames (e.g., between the current frame and the previous frame) exceeds a threshold. If the difference in the maximum raw sensed values between the multiple frames is less than the threshold value, the noise determination circuit 330 can determine that there is no noise in the multiple touch areas.

If it is determined that noise exists, the noise determination circuit 330 may generate a frequency change signal and send the frequency change signal to the control circuit 340 to change the frequency of the drive signal used to drive the touch electrode from the touch section of the current frame or from the subsequent frame.

Furthermore, the noise determination circuit 330 can also perform noise index sensing before changing the frequency of the drive signal. The noise determination circuit 330 can determine whether multiple candidate frequency groups have low noise levels suitable for use as the drive signal STX. For example, the noise determination circuit 330 can also calculate the average of the differences in the maximum raw sense values TSEN_RAW between multiple frames of the candidate frequency groups. Even if any of the aforementioned methods determines that the current frequency is noise-free, the noise determination circuit 330 can change the drive signal frequency only if the average value of the candidate frequency groups is less than a threshold value. If the average value of the candidate group frequency is not less than the threshold value, the frequency of the driving signal can be left unchanged.

The control circuit 340 can supply a drive signal STX to the drive circuit 310. If the noise determination circuit 330 receives a request to change the frequency of the drive signal STX (e.g., a frequency change signal), the control circuit 340 can generate a drive signal STX having a frequency corresponding to the request and supply the drive signal STX to the drive circuit 310. For example, the control circuit 340 can generate a drive signal STX having a changed frequency and send the drive signal STX to the drive circuit 310. The drive circuit 310 can then drive the touch electrode using the drive signal STX having the changed frequency.

The control circuit 340 can generate a control signal CS for controlling the driving circuit 310 and the sensing circuit 320. If the control circuit 340 transmits the control signal CS to the driving circuit 310 and the sensing circuit 320, the driving circuit 310 and the sensing circuit 320 can operate according to the control signal CS.

Noise sensing data can be stored in the storage circuit 350. For example, data related to the raw sensing value TSEN_RAW of each frame, the maximum raw sensing value of each frame, or data related to the touch area can be stored.

FIG4 is a diagram illustrating a noise sensing method using the difference in maximum raw sensed values between frames according to an embodiment.

Referring to FIG4 , the touch sensing device according to an embodiment can sense noise using the difference in the maximum raw sensing value between frames when the number of touch areas between the current frame and the previous frame is the same.

The noise detection circuit of the touch sensing device can obtain the raw sensed value distribution 401 of the previous frame and the raw sensed value distribution 402 of the current frame. In this figure, the raw sensed value distribution 401 of the previous frame and the raw sensed value distribution 402 of the current frame may have the same touch area, including the first touch area I (shaded area). Because the number of touch areas is the same between the current frame and the previous frame, the noise detection circuit can use the difference in the maximum raw sensed value between the frames to perform noise detection.

The first touch area I may be an area corresponding to multiple touch electrodes representing multiple raw sensing values. Each raw sensing value may be represented by a coordinate on the X-axis (X) and the Y-axis (Y). The first touch area I may be an area corresponding to (X2, Y6), (X2, Y5), (X2, Y4), (X3, Y6), (X3, Y5), (X3, Y4), (X3, Y3), (X4, Y5), (X4, Y4), and (X4, Y3). The maximum raw sensing value in the raw sensing value distribution 401 of the previous frame may be 182 at the point (X3, Y5) pointed to by the external object OBJ. On the other hand, the maximum raw sensing value in the raw sensing value distribution 402 of the current frame may be 200 at the point (X3, Y5) pointed to by the external object OBJ.

The noise detection circuit can obtain the difference (i.e., 18) between the maximum raw sense value 200 of the current frame and the maximum raw sense value 182 of the previous frame. The noise detection circuit can obtain the difference in the maximum raw sense values between two consecutive frames for all frames in the above manner and can calculate an average value by averaging these differences.

FIG5 is a display showing a first example of a noise sensing method using geometric features of a touch area according to an embodiment, and FIG6 is a display showing a second example of a noise sensing method using geometric features of a touch area according to an embodiment.

Referring to FIG5 , the touch sensing device according to an embodiment can sense noise using the first geometric features of the current frame when the number of touch areas differs between the current frame and the previous frame.

The noise detection circuit of the touch sensing device can obtain the raw sensed value distribution of the previous frame and the raw sensed value distribution 502 of the current frame. In the above example, the raw sensed value distribution of the previous frame may have one touch area. However, the raw sensed value distribution 502 of the current frame in FIG5 may have two touch areas, including the 1-1 touch area I-1 (shaded area) and the 1-2 touch area I-2 (shaded area), which is different from the raw sensed value distribution of the previous frame. Because the number of touch areas differs between the current frame and the previous frame, the noise detection circuit can use the first geometric feature to perform noise sensing.

The 1-1 touch region I-1 may be the region corresponding to (X2, Y6) and (X3, Y6). The noise determination circuit may determine whether noise is present based on the first geometric characteristics of the 1-1 touch region I-1. For example, the noise determination circuit may determine whether the width H1 of the 1-1 touch region I-1 falls within a predetermined range. Preferably, the predetermined range may indicate that the width of a touch region falls within a length corresponding to two or fewer touch electrodes. In this case, the noise determination circuit may determine that noise is present. Since the width H1 of the 1-1 touch region I-1 corresponds to the length of one touch electrode and thus falls within a predetermined range, the noise determination circuit can determine that noise exists in the 1-1 touch region I-1.

The first-second touch region I-2 may be an area corresponding to (X2, Y4), (X3, Y4), (X3, Y3), (X4, Y4), and (X4, Y3). The noise determination circuit may determine whether noise is present based on the geometric characteristics of the first-second touch region I-2. For example, the noise determination circuit may determine whether the width H2 of the first-second touch region I-2 falls within a predetermined range. The predetermined range may indicate that the width of a touch region falls within a length corresponding to two or fewer touch electrodes, and in this case, the noise determination circuit may determine that noise is present. Because the width H2 of the first-second touch region I-2 corresponds to the length of the two touch electrodes and therefore falls within a predetermined range, the noise detection circuit can determine that noise exists in the first-second touch region I-2.

Referring to FIG6 , the touch sensing device according to an embodiment can sense noise using the second geometric feature of the current frame when the number of touch areas differs between the current frame and the previous frame.

The noise determination circuit can determine whether noise is present based on the second geometric features of the first-first touch region I-1 and the second-second touch region I-2. For example, the noise determination circuit can determine whether the distance D between the first-first touch region I-1 and the second-second touch region I-2 falls within a predetermined range. Preferably, the predetermined range indicates that the distance between multiple touch regions is within a length corresponding to two or fewer touch electrodes. In this case, the noise determination circuit can determine that noise is present. Because the distance D between the 1-1st touch region I-1 and the 1-2nd touch region I-2 corresponds to the length of one touch electrode and is therefore within a predetermined range, the noise determination circuit can determine that noise exists in the 1-1st touch region I-1 and the 1-2nd touch region I-2.

In other words, the first touch area I corresponds to (X2, Y6), (X2, Y5), (X2, Y4), (X3, Y6), (X3, Y5), (X3, Y4), (X3, Y3), (X4, Y5), (X4, Y4), and (X4, Y3) in the previous frame (401 in FIG. 4 ). However, since the first touch area I includes noise, the first touch area I can be divided into the 1-1 touch area I-1 and the 1-2 touch area I-2 in the current frame. The noise detection circuitry of a touch sensing device can determine whether the geometric features between frames meet predetermined conditions and can identify a touch area that has been divided into multiple touch areas as having noise. This is due to the fact that if a large touch area is divided into smaller touch areas due to the presence of noise, the width or amplitude of the divided touch areas is very small, and the distance between these divided touch areas is also very small. Noise sensing using geometric features can be applied to this situation.

FIG7 is a flow chart illustrating an operation of a touch sensing device for sensing noise according to an embodiment.

Referring to FIG. 7 , according to an embodiment, the touch sensing device can perform different noise sensing operations depending on whether the number of touch areas between the current frame and the previous frame is the same.

The noise detection circuit of the touch sensing device can receive raw sensing values from the touch electrode for sensing the touch or proximity of an external object (step S702). The noise detection circuit can receive raw sensing values for each frame.

The noise determination circuit can extract the touch area from the current frame and the previous frame respectively (step S704).

The noise determination circuit can compare the number of touch areas between the current frame and the previous frame (step S706).

If the number of touch areas is the same between the current frame and the previous frame ("Yes" in step S706), the noise determination circuit may calculate the average of the differences in the maximum raw sense values between consecutive frames. The maximum raw sense value difference may be calculated using all consecutive frames (step S708-1). The noise determination circuit may compare the average value with a threshold value (step S710-1). If the average value is greater than the threshold value ("Yes" in step S710-1), the noise determination circuit may determine that noise is present and may control the control circuit and the drive circuit to change the frequency of the drive signal (step S712-1). If the average value is not greater than the threshold value ("No" in step S710-1), the noise determination circuit can determine that there is no noise. The noise determination circuit can perform noise sensing again.

If the number of touch areas differs between the current frame and the previous frame ("No" in step S706), the noise detection circuitry analyzes the geometric characteristics of the touch areas in the current frame (step S708-2). The noise detection circuitry then determines whether the geometric characteristics meet predetermined conditions (step S710-2). The predetermined conditions may include whether the width or amplitude of the touch areas and the distance between the touch areas fall within a predetermined range. If the predetermined conditions are met ("Yes" in step S710-2), the noise determination circuit may determine that noise is present and may control the control circuit and drive circuit to change the frequency of the drive signal (step S712-2). If the predetermined conditions are not met ("No" in step S710-2), the noise determination circuit may determine that noise is not present. The noise determination circuit may perform noise sensing again.

Cross-references to related applications

This application claims priority to Korean Patent Application No. 10-2019-0172325, filed on December 20, 2019, which is incorporated herein by reference for all purposes as if fully set forth herein.

100: Display device

110: Panel

120: Data drive

130: Gate drive device

140: Touch sensor device

DL: Data Line

GL: Gate Line

P: Pixels

SL: Sensing line

TE: Touch electrode

Claims (13)

A touch sensing device includes: a driving circuit configured to drive a touch electrode using a driving signal; a sensing circuit configured to generate a raw sensing value for the touch electrode; and a noise determination circuit configured to determine that noise is contained in touch sensing for one or more touch areas segmented based on the raw sensing value when a distance between two adjacent touch areas segmented based on the raw sensing value is equal to or less than a predetermined distance and when a width of one of the two touch areas is equal to or less than a predetermined width. In the case where the number of touch areas between frames is different, the noise determination circuit determines whether noise is included in the touch sensing based on the distance between the two adjacent touch areas or the width of the touch areas. The touch sensing device according to claim 1, wherein the raw sensing value is generated in the form of a matrix including a plurality of nodes, and when the two touch areas are formed in the form of a node provided between the two touch areas, the noise determination circuit determines that the distance is equal to or less than the predetermined distance. The touch sensing device of claim 1, wherein the noise determination circuit determines whether noise is included in the touch sensing based on a distance between two adjacent touch areas or a width of the touch area after a predetermined frame from the start. The touch sensing device according to claim 1, wherein when the noise determination circuit determines that noise is included in the touch sensing, the driving circuit drives the touch electrode using a driving signal having a changed frequency. The touch sensing device of claim 1, wherein, while the number of touch areas remains the same between frames, the noise determination circuit is configured to extract the maximum value of the raw sensing value for each frame, calculate the difference between the maximum values between the frames, and determine whether the touch sensing includes noise based on a representative value of the difference calculated for multiple frames. The touch sensing device according to claim 5, wherein the representative value is an average value, and when the average value is greater than a threshold value, the noise determination circuit determines that noise is included in the touch sensing. A touch sensing device includes: a driving circuit configured to drive a touch electrode using a driving signal; a sensing circuit configured to generate a raw sensing value for the touch electrode; and a noise determination circuit configured to determine that noise is contained in the touch sensing for one or more touch areas if the width of one of the one or more touch areas segmented based on the raw sensing value is equal to or less than a predetermined width. In the case where the number of touch areas varies between frames, the noise determination circuit determines whether noise is included in the touch sensing based on the width of a touch area. The touch sensing device of claim 7, wherein the raw sensing value is generated in the form of a matrix including a plurality of nodes, and when the width of a touch area is equal to or smaller than the width of a node, the noise determination circuit determines that noise is included in the touch sensing. The touch sensing device of claim 7, wherein the noise determination circuit determines whether noise is included in the touch sensing based on the width of a touch area after a predetermined frame from the beginning. The touch sensing device according to claim 7, wherein when the noise determination circuit determines that noise is included in the touch sensing, the drive circuit drives the touch electrode using a drive signal with a changed frequency. The touch sensing device of claim 7, wherein, while the number of touch areas remains the same between the frames, the noise determination circuit is configured to extract the maximum value of the raw sensing value for each frame, calculate the difference between the maximum values between the frames, and determine whether noise is included in the touch sensing based on a representative value of the difference calculated for multiple frames. The touch sensing device according to claim 11, wherein the representative value is an average value, and when the average value is greater than a threshold value, the noise determination circuit determines that noise is included in the touch sensing. A touch sensing device includes: a drive circuit configured to drive a touch electrode using a drive signal; a sensing circuit configured to generate a raw sensing value for the touch electrode for each frame; and a noise determination circuit configured to extract a maximum value of the raw sensing value for each frame, calculate the difference between the maximum values between frames, and determine whether noise is included in the touch sensing based on a representative value of the differences calculated for multiple frames.