Touch sensing device

Abstract

The present invention provides a touch sensing device. The present invention relates to a touch sensing technology for sensing noise to avoid the noise, which enables to prevent in advance the possibility that the frequency of a driving signal is changed in a predetermined order or randomly by changing the frequency of the driving signal in a frequency in which the influence of the noise is minimized.

Description

Technical Field

[0001] This embodiment relates to touch sensing technology for sensing noise. Background Technology

[0002] Touch sensing technology refers to the technology used to identify external objects that approach or touch a touch panel. The touch panel is placed on a flat surface in the same position as the display panel. Therefore, users can input user operation signals using the touch panel while viewing an image on the display panel. This method of generating user operation signals provides significant user intuitiveness compared to other existing methods of inputting user operation signals (e.g., input via a mouse or keyboard).

[0003] Based on the advantages mentioned above, touch sensing technology is being applied to various types of electronic devices, including display panels. A touch sensing device can supply drive signals to drive electrodes arranged in a touch panel and receive response signals from sensing electrodes, thereby sensing the touch or proximity of an external object relative to the touch panel. The touch panel can generate capacitance between the drive electrodes and the sensing electrodes, and changes in capacitance can indicate the touch or proximity of an external object.

[0004] On the other hand, the touch panel may contain noise. When an external object touches the touch panel, the noise may be transmitted through the external object, which may cause malfunctions in the touch panel.

[0005] Traditionally, to sense noise, it is determined whether the frequency of the noise contained in the response signal is similar to the frequency of the response signal. If the frequency of the noise contained in the response signal is similar to the frequency of the response signal, the frequency of the drive signal is changed. If the response signal fluctuates more than a predetermined value relative to a reference value, it can be determined that the frequency of the noise is similar to the frequency of the response signal. Here, the reference value can be data obtained under conditions where there is no external object touching or approaching, or under conditions where no noise is present.

[0006] However, the traditional methods described above can detect noise with the same frequency as the driving signal, but cannot detect various types of noise such as harmonic noise.

[0007] In this regard, this embodiment provides a technique for effectively sensing various types of noise that occur in touch sensing. Summary of the Invention

[0008] In this context, the objective of this embodiment is to provide a technique for sensing noise using the average of the differences between the maximum original sensed values ​​between consecutive frames, or using the geometric features of the touch area based on the number of touch or proximity areas.

[0009] Therefore, 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 touch sensing for one or more touch areas segmented according to the sensing value contains noise if the distance between two adjacent touch areas segmented according to the sensing value is equal to or less than a predetermined distance, and if the width of one of the two touch areas is equal to or less than a predetermined width.

[0010] The sensed value may be generated in the form of a matrix including multiple nodes, and in the case where the two touch areas are formed with a node between them, the noise determination circuit may determine that the distance is equal to or less than the predetermined distance.

[0011] When the number of touch areas differs between frames, the noise detection circuit can determine whether noise is present in touch sensing based on the distance between two adjacent touch areas or the width of the touch area.

[0012] The noise detection circuit can determine whether there is noise in the touch sensing based on the distance between two adjacent touch areas or the width of the touch area after a predetermined frame from the start.

[0013] If the noise detection circuit determines that there is noise in the touch sensing, the driving circuit can use a driving signal with a changed frequency to drive the touch electrode.

[0014] When the number of touch areas remains the same across frames, the noise detection 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 present in the touch sensing based on a representative value of the difference calculated for multiple frames.

[0015] The representative value can be an average value, and if the average value is greater than a threshold, the noise detection circuit can determine that there is noise in the touch sensing.

[0016] 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 touch sensing for the one or more touch areas contains noise if 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.

[0017] The sensed value can be generated in the form of a matrix including multiple nodes, and the noise detection circuit can determine that there is noise in the touch sensing when the width of a touch area is equal to or less than the width of a node.

[0018] The noise detection circuit can determine whether there is noise in the touch sensing based on the width of a touch area after a predetermined frame from the start.

[0019] If the noise detection circuit determines that there is noise in the touch sensing, the driving circuit can use a driving signal with a changed frequency to drive the touch electrode.

[0020] The noise detection circuit can determine whether there is noise in touch sensing based on the width of a touch area, provided that the number of touch areas differs only between frames.

[0021] When the number of touch areas remains the same across frames, the noise detection 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 present in the touch sensing based on a representative value of the difference calculated for multiple frames.

[0022] The representative value can be an average value, and if the average value is greater than a threshold, the noise detection circuit can determine that there is noise in the touch sensing.

[0023] 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 for each frame; and a noise determination circuit configured to extract the maximum value of the 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 difference calculated for multiple frames.

[0024] As described above, according to this embodiment, various types of noise, such as harmonic noise, can be sensed, thereby reducing false touch recognition. Attached Figure Description

[0025] 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:

[0026] Figure 1 This is a diagram illustrating the structure of a display device according to an embodiment;

[0027] Figure 2 This is a schematic diagram illustrating a touch sensing system according to an embodiment;

[0028] Figure 3 This is a diagram illustrating the structure of a touch sensing device according to an embodiment;

[0029] Figure 4 This is a diagram illustrating a noise sensing method according to an embodiment, using the difference between the maximum original sensed values ​​between frames;

[0030] Figure 5 This is a display illustrating a first example of a noise sensing method using geometric features of a touch area according to an embodiment;

[0031] Figure 6 This is a display illustrating a second example of a noise sensing method using geometric features of a touch area according to an embodiment; and

[0032] Figure 7 This is a flowchart illustrating the operation of a touch sensing device sensing noise according to an embodiment. Detailed Implementation

[0033] Figure 1 This is a diagram illustrating the structure of a display device according to an embodiment.

[0034] refer to Figure 1 The display device 100 includes a panel 110, a data driving device 120, a gate driving device 130, and a touch sensing device 140, etc.

[0035] Multiple data lines DL connected to the data driving device 120 can be formed on the panel 110, and multiple gate lines GL connected to the gate driving device 130 can be formed on the panel 110. In addition, multiple pixels P can be defined at the points where the multiple data lines DL and the multiple gate lines GL intersect in the panel 110.

[0036] A transistor can be formed in each pixel P, the transistor having a first electrode (e.g., source electrode or drain electrode) connected to a data line DL, a gate electrode connected to a gate line GL, and a second electrode (e.g., drain electrode or source electrode) connected to a display electrode.

[0037] Additionally, multiple touch electrodes TE can be further arranged in the panel 110 in a spaced-apart manner. One or more pixels P can be located in the area where the touch electrodes TE are located.

[0038] Panel 110 may include a display panel and a touch panel (e.g., a touchscreen panel (TSP)), wherein the display panel and the touch panel may share some components with each other. 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 such a panel 110 is referred to as an "integrated panel" given that some components of the display panel and the touch panel are shared, the invention is not limited thereto. Furthermore, in-cell type 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 described above, and the panels to which the invention applies are not limited to in-cell type panels.

[0039] The data drive device 120 supplies data signals to the data line DL to display images on each pixel P in the panel 110.

[0040] The data driver device 120 may include at least one data driver integrated circuit, which may be connected to the bonding pads of the panel 110 via tape autobonding (TAB) or glass flip-chip (COG) bonding, or may be directly formed in the panel 110. In some cases, the data driver integrated circuit may be formed as an integrated circuit on the panel 110. Alternatively, the data driver device 120 may be implemented using thin-film flip-chip (COF).

[0041] The gate driving device 130 sequentially supplies scan signals to the gate line GL to turn on or off the transistors located in each pixel P.

[0042] Depending on the driving method, the gate driving device 130 may be located on only one side of the panel 110 as shown in the figure, or two separate gate driving devices may be located on both sides of the panel 110.

[0043] Additionally, the gate driving device 130 may include at least one gate driver integrated circuit, which may be connected to the bonding pads of the panel 110 via tape-on-brush (TAB) or glass-on-chip (COG) bonding, or may be directly formed on the panel 110 via panel gate in-line (GIP) bonding. In some cases, the gate driver integrated circuit may be integrated onto the panel 110. Alternatively, the gate driving device 130 may be implemented via thin-film flip-chip (COF) bonding.

[0044] The touch sensing device 140 applies a drive signal to all or part of the plurality of touch electrodes TE connected to the sensing line SL.

[0045] As shown in the figure, the touch sensing device 140 can be disposed outside the data driving device 120 and the gate driving device 130 as a separate element from the data driving device 120 and the gate driving device 130. However, depending on the implementation, the touch sensing device 140 can be implemented as an internal element of another separate driver integrated circuit that includes at least one of the data driving device 120 and the gate driving device 130; or it can be implemented as an internal element of the data driving device 120 or the gate driving device 130.

[0046] Therefore, the operation of the touch sensing device 140 applying drive signals to all or part of the plurality of touch electrodes TE can be understood as the operation of a separate driver integrated circuit including the touch sensing device 140 applying drive signals to all or part of the plurality of touch electrodes TE. Alternatively, depending on the design, this operation can be considered as the operation of the data driving device 120 or the gate driving device 130 of the touch sensing device 140 applying drive signals to all or part of the plurality of touch electrodes TE.

[0047] The touch sensing device 140 is not limited to a specific implementation and design, and may be implemented as a standalone element or as an element disposed inside or outside another element, as long as it can achieve the same or similar functions as those described in this specification.

[0048] Additionally, although a single touch sensing device 140 is shown in the figure within the display device 100, the display device 100 may include two or more touch sensing devices 140.

[0049] On the other hand, sensing lines SL are required to connect to each touch electrode TE so that the touch sensing device 140 can apply drive signals 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 along a second direction (e.g., horizontal direction) to connect to each touch electrode TE, thereby sending drive signals to these touch electrodes TE.

[0050] On the other hand, the display device 100 can use a capacitive touch method that detects the approach or touch of an object by sensing changes in capacitance via the touch electrode TE.

[0051] Capacitive touch methods can be classified, for example, into mutual capacitance touch methods and self-capacitance touch methods.

[0052] In a mutual capacitance touch method, which is 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) that is coupled to the Tx electrode is sensed. In the mutual capacitance touch method, the value sensed at the Rx electrode changes according to the proximity or touch of an object such as a finger or pen, and the value sensed at the Rx electrode is used to detect the presence or absence of a touch, as well as touch coordinates, etc.

[0053] In the self-capacitance touch method, another type of capacitive touch method, a drive signal is applied to the touch electrode TE, and then the corresponding touch electrode TE is sensed. In the self-capacitance touch method, the value sensed at the corresponding touch electrode TE changes according to the proximity or touch of an object such as a finger or pen, and the sensed value is used to detect the presence or absence of a touch, as well as touch coordinates. In the self-capacitance touch method, since the touch electrode TE to which the drive signal is applied and the touch electrode TE to which the value is sensed are the same, there is no distinction between the Tx and Rx electrodes.

[0054] The display device 100 can use one of the two capacitive touch methods described above (mutual capacitance touch method and self-capacitance touch method). However, for ease of explanation, this specification will assume the use of the self-capacitance touch method.

[0055] On the other hand, the display device 100 can drive the touch electrodes TE separately for the display section and the touch section. For example, the touch sensing device 140 of the display device 100 may not apply a drive signal to all or part of the touch electrodes TE in the section where data signals are supplied.

[0056] Furthermore, the display device 100 can drive the touch electrode TE without separating the display segment and the touch segment. For example, the touch sensing device 140 of the display device 100 can apply a drive signal to all or part of the touch electrode TE in the segment where data signals are supplied.

[0057] Figure 2 This is a schematic diagram illustrating a touch sensing system according to an embodiment.

[0058] refer to Figure 2 The touch sensing system 200 may include a panel 110 and a touch sensing device 140.

[0059] The panel 110 may have multiple touch electrodes TE configured thereon.

[0060] The touch sensing device 140 can supply a drive signal STX to the touch electrode TE. The drive signal STX can be a voltage or current signal, and a voltage drive signal STX can be defined as a "drive voltage". The drive signal can include a drive cycle comprising a first time period and a second time period.

[0061] The touch sensing device 140 can receive a response signal SRX to the drive signal STX from the touch electrode TE, and can demodulate the response signal SRX to 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.

[0062] Figure 3 This is a diagram illustrating the structure of a touch sensing device according to an embodiment.

[0063] refer to Figure 3 The touch sensing device 140 may include a driving circuit 310, a sensing circuit 320, a noise detection circuit 330, a control circuit 340, and a storage circuit 350.

[0064] The driving circuit 310 can supply a driving signal STX with a certain frequency to the touch electrode. The driving circuit 310 can use driving signals STX with different frequencies to drive the touch electrode. For example, the driving circuit 310 can receive a driving signal STX with a changed frequency from the control circuit 340, and can use the changed frequency to drive the touch electrode.

[0065] The sensing circuit 320 can receive a response signal SRX to the drive signal STX from the touch electrode. The sensing circuit 320 can receive response signals SRX with different frequencies in response to the drive signal STX. For example, if the drive circuit 310 uses a changed frequency to drive the touch electrode, the sensing circuit 320 can receive a response signal SRX with a changed frequency that is different from the previous frequency.

[0066] The sensing circuit 320 can sense 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, thereby generating touch sensing data. The sensing circuit 320 can send the touch sensing data to the noise judgment circuit 330.

[0067] Touch sensing data can include the raw sensing value TSEN_RAW generated by demodulating the response signal SRX. The raw sensing value TSEN_RAW can be, for example, the time integral 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 generated 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 screen.

[0068] The sensing circuit 320 can generate the raw sensing value TSEN_RAW of the touch electrodes. If a touch electrode is sensed, a raw sensing value TSEN_RAW can be generated for each touch electrode. The raw sensing value TSEN_RAW can be generated based on the configuration of the touch electrodes on the panel. A change in capacitance may occur in the touch electrodes where an external object touches or approaches, and the raw sensing value TSEN_RAW may change according to the change in capacitance. The change in the raw sensing value TSEN_RAW may occur in multiple touch electrodes surrounding the touch electrode that is the point of touch or proximity. The raw sensing value TSEN_RAW may increase or decrease in the multiple touch electrodes affected by touch or proximity compared to touch electrodes that are not affected by touch or proximity. An area in the touch panel where the raw sensing value TSEN_RAW changes in the multiple touch electrodes affected by touch or proximity may be referred to as a "touch area".

[0069] The sensing circuit 320 can generate raw sensing values ​​in the form of a matrix including multiple nodes. In addition, the sensing circuit 320 can classify nodes whose raw sensing values ​​are equal to or greater than a predetermined reference value and are arranged in an adjacent manner into a touch area, and can assign labels to the corresponding touch areas.

[0070] The touch electrode most affected by touch or proximity (i.e., the touch electrode at the point of touch or proximity) can have the most maximized original sense value TSEN_RAW (e.g., maximum or minimum value). In the following text, the touch electrode most affected by touch or proximity may be referred to as the "point touch electrode".

[0071] The sensing circuit 320 can generate the raw sensing value TSEN_RAW of the touch electrode for each frame. The sensing circuit 320 can generate the raw sensing value TSEN_RAW using a first method and a second method. The first method scans all lines of the display panel in a frame before sensing the touch panel, and the second method scans a portion of the lines of the display panel in a frame before sensing the touch panel. The sensing circuit 320 can generate the raw sensing value TSEN_RAW of the touch electrode for each frame using either the first method or the second method.

[0072] The noise detection circuit 330 can compare the number of touch areas across multiple frames. For example, the noise detection circuit 330 can calculate the number of touch areas for each frame in two or more frames that are temporally close, and can determine whether the number of touch areas is the same or different between these frames. Here, two or more frames that are temporally close can refer to consecutively reproduced frames such as the current frame and the previous frame or the current frame and the subsequent frame.

[0073] To identify the number of touch areas, the noise detection circuit 330 can use the distribution of changes in the capacitance of the touch electrodes (e.g., the original sensed value TSEN_RAW). For example, the noise detection circuit 330 can identify interconnected original sensed values ​​TSEN_RAW as a touch area. If a discontinuity or intermittent point where the original sensed value TSEN_RAW is not present is found in a touch area, the noise detection circuit 330 can determine that a new touch area exists based on this situation.

[0074] The noise detection circuit 330 can use the representative value of the raw sensing value TSEN_RAW between multiple frames, or it can use the geometric features of the touch area based on the comparison results, to determine whether there is noise in the touch area.

[0075] Specifically, if the number of touch areas remains the same across multiple frames, the noise determination circuit 330 can use the average of the differences between the maximum original sensing values ​​across multiple frames as a representative value, and if it is determined that noise exists in the touch area, it can control the control circuit 340 to change the frequency of the drive signal.

[0076] For example, when the display device drives N frames (N is a natural number of 2 or greater), the noise determination circuit 330 can calculate the number of touch areas in the current frame and the previous frame from frame 1 to frame N. If, as a result of comparing the number of touch areas using the noise determination circuit 330, the number of touch areas remains the same, then the noise determination circuit 330 can determine that the number of touch areas is the same across multiple frames. One or more touch areas may exist, and the number of touch areas may be the same between the current frame and the previous frame.

[0077] Next, the noise detection circuit 330 can calculate the difference between the maximum original sensed values ​​between two consecutive frames. The noise detection circuit 330 can calculate the difference between the maximum original sensed value of the (N-1)th frame and the maximum original sensed value of the Nth frame. Additionally, the noise detection circuit 330 can calculate the difference between the maximum original sensed value of the (N-2)th frame and the maximum original sensed value of the (N-1)th frame. The noise detection circuit 330 can calculate the difference between the maximum original sensed values ​​between two consecutive frames from frame 1 to frame N using the above method, thereby obtaining N-1 difference values. The noise detection circuit 330 can obtain the average of these N-1 difference values. Therefore, the noise detection circuit 330 can calculate the average of the differences between the maximum original sensed values ​​between frames.

[0078] The noise detection circuit 330 can use a threshold value to determine whether noise exists in the touch area based on an average value. If the average value is greater than the threshold value, the noise detection circuit 330 can determine that noise exists. On the other hand, if the average value is not greater than the threshold value, the noise detection circuit 330 can determine that noise does not exist.

[0079] If noise is detected, the noise detection circuit 330 can 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 a touch segment in the current frame or from a subsequent frame.

[0080] In addition, if the number of touch areas differs between multiple frames, the noise determination circuit 330 can use the geometric features of the touch areas, and if it determines that noise exists in the touch areas, it can control the control circuit 340 to change the frequency of the drive signal.

[0081] For example, when the display device drives N frames (N is a natural number of 2 or greater), the noise determination circuit 330 can calculate the number of touch areas in the current frame and the previous frame from frame 1 to frame N. If, as a result of comparing the number of touch areas using the noise determination circuit 330, the number of touch areas is different, then the noise determination circuit 330 can determine that the number of touch areas is different between multiple frames. One or more touch areas may exist, and the number of touch areas may be different between the current frame and the previous frame.

[0082] Next, the noise detection circuit 330 can derive the geometric features of the touch area for each frame. The noise detection circuit 330 can identify the shape or position of the touch area and the distance between touch areas as geometric features 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.

[0083] The noise detection circuit 330 can determine whether noise exists in the touch area based on geometric features and predetermined conditions.

[0084] 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 can determine that noise exists in the touch area. The predetermined range of width or amplitude can be the length corresponding to one or two touch electrodes that are unlikely to experience individual and independent touches.

[0085] For example, if the distance (interval) between multiple touch areas in the current frame falls within a predetermined range, the noise determination circuit 330 can determine that noise exists in the touch areas. The predetermined range of distance can be a length corresponding to one or two touch electrodes that are unlikely to experience individual and independent touches. The distance can be measured between the point touch electrode and the multiple touch areas, or it can be measured based on the touch electrode located at the outermost edge of the touch area.

[0086] Additionally, the noise detection circuit 330 can consider whether the difference between the maximum original sensed values ​​across multiple frames is greater than a threshold to determine noise based on the geometric features of the touch area. The noise detection circuit 330 can compare the difference between the maximum original sensed values ​​between the current frame and the previous frame with a threshold.

[0087] Because of the low sensitivity of touch, the width or breadth of the touch can fall within a defined range when a touch or proximity is about to begin. That is, the width or breadth of the touch area can be as short as the length corresponding to one or two touch electrodes. Even if the width or breadth of the touch area falls within the defined range, there may be no noise when a touch or proximity is about to begin. Therefore, the noise detection circuit 330 can determine that noise exists in multiple touch areas only if the difference between the maximum original sensed values ​​between multiple frames (e.g., between the current frame and the previous frame) is greater than a threshold. If the difference between the maximum original sensed values ​​between multiple frames is less than the threshold, the noise detection circuit 330 can determine that there is no noise in the multiple touch areas.

[0088] If noise is detected, the noise detection circuit 330 can 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 segment of the current frame or from the subsequent frame.

[0089] Furthermore, the noise assessment circuit 330 can also perform noise figure sensing before changing the frequency of the drive signal. The noise assessment circuit 330 can determine whether multiple candidate frequency groups have low noise that can be used as the drive signal STX. For example, the noise assessment circuit 330 can also calculate the average difference of the maximum original sensed values ​​TSEN_RAW between multiple frames of the candidate frequency groups. Even if noise is determined to exist at the current frequency by any of the methods described above, the noise assessment circuit 330 can only change the frequency of the drive signal if the average value of the candidate frequency groups is less than a threshold. If the average value of the candidate frequency groups is not less than the threshold, the frequency of the drive signal can remain unchanged.

[0090] The control circuit 340 can supply a drive signal STX to the drive circuit 310. If the noise judgment circuit 340 receives a request (e.g., a frequency change signal) to change the frequency of the drive signal STX, the control circuit 340 can generate a drive signal STX with a frequency corresponding to the request and supply this drive signal STX to the drive circuit 310. For example, the control circuit 340 can generate a drive signal STX with a changed frequency and send this drive signal STX to the drive circuit 310. The drive circuit 310 can then use the drive signal STX with the changed frequency to drive the touch electrode.

[0091] The control circuit 340 can generate a control signal CS for controlling the drive circuit 310 and the sensing circuit 320. If the control circuit 340 sends the control signal CS to the drive circuit 310 and the sensing circuit 320, the drive circuit 310 and the sensing circuit 320 will operate according to the control signal CS.

[0092] Noise sensing data can be stored in 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 of the touch area can be stored.

[0093] Figure 4 This is a diagram illustrating a noise sensing method according to an embodiment, which uses the difference between the maximum original sensed values ​​between frames.

[0094] refer to Figure 4 According to the embodiment, when the number of touch areas is the same between the current frame and the previous frame, the touch sensing device can use the difference between the maximum original sensing values ​​between frames to sense noise.

[0095] The noise determination circuit of the touch sensing device can obtain the original sensing value distribution 401 of the previous frame and the original sensing value distribution 402 of the current frame. In this figure, the original sensing value distribution 401 of the previous frame and the original sensing value distribution 402 of the current frame may have the same touch area including the first touch area I (shaded area). Since the number of touch areas is the same between the current frame and the previous frame, the noise determination circuit can use the difference between the maximum original sensing values ​​between the frames to perform noise sensing operation.

[0096] The first touch area I can be an area corresponding to multiple touch electrodes representing multiple raw sense values. Each raw sense value can be represented by coordinates on the X-axis (X) and Y-axis (Y). The first touch area I can 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 sense value in the raw sense value distribution 401 of the previous frame can be 182 at the point (X3,Y5) pointed to by the external object OBJ. On the other hand, the maximum raw sense value in the raw sense value distribution 402 of the current frame can be 200 at the point (X3,Y5) pointed to by the external object OBJ.

[0097] The noise detection circuit can obtain the difference (i.e., 18) between the maximum original sensed value 200 of the current frame and the maximum original sensed value 182 of the previous frame. The noise detection circuit can obtain the difference between the maximum original sensed values ​​between two consecutive frames in all frames in the manner described above, and can calculate the average value by averaging these differences.

[0098] Figure 5 This is a display illustrating a first example of a noise sensing method using geometric features of a touch area according to an embodiment, and Figure 6 This is a display illustrating a second example of a noise sensing method using geometric features of a touch area, according to an embodiment.

[0099] refer to Figure 5 According to the embodiment, when the number of touch areas differs between the current frame and the previous frame, the touch sensing device can use the first geometric feature of the current frame to sense noise.

[0100] The noise determination circuit of the touch sensing device can obtain the original sensing value distribution of the previous frame and the original sensing value distribution of the current frame 502. In the example above, the original sensing value distribution of the previous frame may have a touch area. However, Figure 5 The original sensed value distribution 502 of the current frame may have two touch regions, including a first-1 touch region I-1 (shaded region) and a first-2 touch region I-2 (shaded region), which is different from the original sensed value distribution of the previous frame. Since the number of touch regions differs between the current frame and the previous frame, the noise determination circuit can use the first geometric feature to perform noise sensing operation.

[0101] The first-1 touch area I-1 can be the area corresponding to (X2, Y6) and (X3, Y6). The noise detection circuit can determine whether noise exists based on a first geometric feature of the first-1 touch area I-1. For example, the noise detection circuit can determine whether the width H1 of the first-1 touch area I-1 falls within a predetermined range. Preferably, this predetermined range can indicate that the width of a touch area falls within a length corresponding to two or fewer touch electrodes. In this case, the noise detection circuit can determine that noise is present. Since the width H1 of the first-1 touch area I-1 corresponds to the length of a touch electrode and thus falls within the predetermined range, the noise detection circuit can determine that noise exists in the first-1 touch area I-1.

[0102] The first and second touch areas I-2 can be areas corresponding to (X2,Y4), (X3,Y4), (X3,Y3), (X4,Y4), and (X4,Y3). The noise detection circuit can determine the presence of noise based on the geometric characteristics of the first and second touch areas I-2. For example, the noise detection circuit can determine whether the width H2 of the first and second touch areas I-2 falls within a predetermined range. This predetermined range may indicate that the width of a touch area falls within the length corresponding to two or fewer touch electrodes, and in this case, the noise detection circuit can determine that noise is present. Since the width H2 of the first and second touch areas I-2 corresponds to the length of two touch electrodes and thus falls within the predetermined range, the noise detection circuit can determine that noise exists in the first and second touch areas I-2.

[0103] refer to Figure 6 According to the embodiment, when the number of touch areas differs between the current frame and the previous frame, the touch sensing device can use the second geometric feature of the current frame to sense noise.

[0104] The noise detection circuit can determine the presence of noise based on the second geometric features of the first-1 touch area I-1 and the first-2 touch area I-2. For example, the noise detection circuit can determine whether the distance D between the first-1 touch area I-1 and the first-2 touch area I-2 falls within a predetermined range. Preferably, this predetermined range can indicate that the distance between multiple touch areas is within a length corresponding to two or fewer touch electrodes. In this case, the noise detection circuit can determine that noise is present. Since the distance D between the first-1 touch area I-1 and the first-2 touch area I-2 corresponds to the length of one touch electrode and thus falls within the predetermined range, the noise detection circuit can determine that noise exists in the first-1 touch area I-1 and the first-2 touch area I-2.

[0105] In other words, the first touch area I is the same as the previous frame ( Figure 4 The regions corresponding to (X2,Y6), (X2,Y5), (X2,Y4), (X3,Y6), (X3,Y5), (X3,Y4), (X3,Y3), (X4,Y5), (X4,Y4), and (X4,Y3) in 401 are divided into touch regions I-1 and I-2 in the current frame due to noise in the first touch region I. The noise detection circuit of the touch sensing device can determine whether the geometric features meet predetermined conditions between frames and can determine that a touch region divided into multiple touch regions is noisy. This is because if a large touch region is divided into smaller touch regions due to noise, the width or amplitude of the divided touch regions is very small and the distance between these divided touch regions is very small. Noise sensing using geometric features can be applied to this situation.

[0106] Figure 7 This is a flowchart illustrating the operation of a touch sensing device sensing noise according to an embodiment.

[0107] refer to Figure 7 According to an embodiment, the touch sensing device can perform different noise sensing operations depending on whether the number of touch areas is the same between the current frame and the previous frame.

[0108] The noise determination circuit of the touch sensing device can receive raw sensing values ​​of the touch electrodes for sensing the touch or proximity of an external object (step S702). The noise determination circuit can receive raw sensing values ​​for each frame.

[0109] The noise detection circuit can extract the touch area from the current frame and the previous frame respectively (step S704).

[0110] The noise detection circuit can compare the number of touch areas between the current frame and the previous frame (step S706).

[0111] If the number of touch areas is the same between the current frame and the previous frame ("Yes" in step S706), the noise detection circuit can calculate the average of the differences between the maximum original sensed values ​​between consecutive frames. The maximum original sensed value difference can be calculated using consecutive frames of all frames (step S708-1). The noise detection circuit can compare the average value with a threshold (step S710-1). If the average value is greater than the threshold ("Yes" in step S710-1), the noise detection circuit can determine that noise exists and can control the control circuit and drive circuit to change the frequency of the drive signal (step S712-1). If the average value is not greater than the threshold ("No" in step S710-1), the noise detection circuit can determine that no noise exists. The noise detection circuit can then perform noise sensing again.

[0112] If the number of touch areas differs between the current frame and the previous frame (No in step S706), the noise detection circuit can analyze the geometric features of the touch areas in the current frame (step S708-2). The noise detection circuit can determine whether the geometric features meet a predetermined condition (step S710-2). This predetermined condition can indicate whether the width or amplitude of the touch area and the distance between touch areas fall within a predetermined range. If the predetermined condition is met (Yes in step S710-2), the noise detection circuit can determine that noise exists and can control the control circuit and the drive circuit to change the frequency of the drive signal (step S712-2). If the predetermined condition is not met (No in step S710-2), the noise detection circuit can determine that there is no noise. The noise detection circuit can perform noise sensing again.

[0113] Cross-references to related applications

[0114] This application claims priority to Korean Patent Application No. 10-2019-0172325, filed on December 20, 2019, which, as set forth in its entirety herein, is incorporated herein by reference for all purposes.

Claims

1. 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 sensing value for the touch electrode for each frame; and a noise judgment circuit configured to judge that noise is included in touch sensing for one or more touch detection regions segmented from the sensing value, in a case where a distance between two adjacent touch detection regions segmented from the sensing value is equal to or less than a predetermined distance, and in a case where a width of one of the two adjacent touch detection regions is equal to or less than a predetermined width, wherein the noise judgment circuit is configured to judge whether noise is included in touch sensing, according to the distance between the two adjacent touch detection regions or the width of the one of the two adjacent touch detection regions, only in a case where the number of touch detection regions differs between frames.

2. The touch sensing apparatus of claim 1, wherein, The sensing value is generated in the form of a matrix including a plurality of nodes, and in a case where the two touch detection regions are formed in a form in which one node is provided between the two touch detection regions, the noise judgment circuit judges that the distance is equal to or less than the predetermined distance.

3. The touch sensing apparatus of claim 1, wherein, The noise judgment circuit judges whether noise is included in touch sensing, according to the distance between two adjacent touch detection regions or the width of one of the two adjacent touch detection regions, after a predetermined number of frames from the start.

4. The touch sensing apparatus of claim 1, wherein, In a case where the noise judgment circuit judges that noise is included in touch sensing, the drive circuit drives the touch electrode using a drive signal in which the frequency is changed.

5. The touch sensing apparatus of claim 1, wherein, In a case where the number of touch detection regions remains the same between the frames, the noise judgment circuit is configured to extract a maximum value of the sensing value for each frame, calculate a difference value of the maximum values between the frames, and judge whether noise is included in touch sensing, according to a representative value of the difference values calculated for a plurality of frames.

6. The touch sensing apparatus of claim 5, wherein, The representative value is an average value, and in a case where the average value is greater than a threshold value, the noise judgment circuit judges that noise is included in touch sensing.

7. 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 sensing value for the touch electrode for each frame; and a noise judgment circuit configured to judge that noise is included in touch sensing for one or more touch detection regions segmented from the sensing value, in a case where a width of one of the one or more touch detection regions is equal to or less than a predetermined width, wherein the noise judgment circuit is configured to judge whether noise is included in touch sensing, according to the width of the one of the one or more touch detection regions, only in a case where the number of touch detection regions differs between frames.

8. The touch sensing apparatus of claim 7, wherein, The sensing value is generated in the form of a matrix including a plurality of nodes, and in a case where the width of the one of the one or more touch detection areas is equal to or smaller than the width of one node, the noise judgment circuit judges that noise is included in touch sensing.

9. The touch sensing apparatus of claim 7, wherein, The noise judgment circuit judges whether noise is included in touch sensing according to the width of the one of the one or more touch detection areas after a predetermined number of frames from the start.

10. The touch sensing apparatus of claim 7, wherein, In a case where the noise judgment circuit judges that noise is included in touch sensing, the drive circuit drives the touch electrode using a drive signal whose frequency is changed.

11. The touch sensing apparatus of claim 7, wherein, In a case where the number of touch detection areas remains the same between the frames, the noise judgment circuit is configured to extract a maximum value of the sensing value for each frame, calculate a difference value of the maximum values between the frames, and judge whether noise is included in touch sensing according to a representative value of the difference values calculated for a plurality of frames.

12. The touch sensing apparatus of claim 11, wherein, The representative value is an average value, and in a case where the average value is greater than a threshold value, the noise judgment circuit judges that noise is included in touch sensing.

13. 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 sensing value for the touch electrode for each frame; and a noise judgment circuit configured to compare the number of touch detection areas between frames, in a case where the number of touch detection areas remains the same between the frames, extract a maximum value of the sensing value for each frame, calculate a difference value of the maximum values between the frames, and judge whether noise is included in touch sensing according to a representative value of the difference values calculated for a plurality of frames.

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