Touch sensing device and method for avoiding noise in touch sensing device

Abstract

A touch sensing device and a method for avoiding noise in the touch sensing device. The present invention relates to a touch sensing technology for sensing noise and avoiding noise, which prevents the possibility of the frequency of a driving signal changing in a predetermined order or randomly by changing the frequency of the driving signal at a frequency least affected by noise.

Description

Technical Field

[0001] The present embodiment relates to a touch sensing technology for sensing and avoiding noise. Background Art

[0002] The technology used to sense external objects approaching or touching a touch panel is called touch sensing technology. The touch panel is placed on a plane in the same position as the display panel, so that the user can input user manipulation signals through the touch panel while viewing the image on the display panel. This user manipulation signal generation method provides a higher level of user intuitiveness compared to other traditional user manipulation signal input schemes (for example, mouse input scheme or keyboard input scheme).

[0003] As a result of these advantages, touch sensing technology has been applied to various electronic devices including display panels. A touch sensing device can supply drive signals to drive electrodes arranged in a touch panel and can receive response signals formed in the sensing signals, thereby sensing the touch or proximity of an external object to the touch panel. In the touch panel, capacitance is formed 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 contacts the touch panel, the noise may be transmitted through the external noise, and the touch panel may malfunction accordingly.

[0005] Conventional methods for addressing noise interference determine whether a drive signal is noisy. If so, the frequency of the drive signal is changed from its current frequency to a predefined frequency. For example, if three frequencies are used as drive signals in a predetermined order, one frequency is used to drive the touch electrodes, while the remaining two frequencies remain idle. If the first frequency used is noisy, one of the remaining two frequencies is selected based on the order and used to drive the touch electrodes. If the selected frequency also exhibits noise, the last frequency is used.

[0006] This conventional method has the following problem: because the frequency of the drive signal changes in a predetermined order, it may not be possible to consider whether the new frequency introduced in response to the frequency change is noisy. In other words, the new frequency may also be noisy. Furthermore, if the new frequency is noisy, the process may become inefficient due to frequent switching to different frequencies.

[0007] In this regard, the present embodiment seeks to provide a technique for effectively avoiding noise occurring during touch sensing. Summary of the Invention

[0008] In view of the above background, one aspect of the present invention is to provide a technique of measuring noise associated with individual frequencies in advance and driving a touch electrode by a driving signal having a frequency with minimal noise.

[0009] To this end, in one aspect, the present invention provides a touch sensing device, comprising: a driving circuit configured to drive a touch electrode with a driving signal having a first frequency to sense the touch or approach of an external object, and to drive the touch electrode with a driving signal having a second frequency to measure noise; a sensing circuit configured to receive a response signal with the first frequency and the second frequency in response to the driving signals with the first frequency and the second frequency; and a noise control circuit configured to pre-acquire measurement data related to a result of measuring the noise of the response signal with the second frequency, to determine whether the response signal with the first frequency has noise, and to determine, based on the measurement data, whether to use the driving signal with the second frequency to sense the touch or approach of an external object according to the determination result.

[0010] In the device, the driving circuit can drive the touch electrode by a driving signal having a third frequency; the sensing circuit can receive a response signal having the third frequency in response to the driving signal having the third frequency; if the response signal having the first frequency has noise, the noise control circuit can determine the frequency with the least noise between the second frequency and the third frequency based on the measurement data.

[0011] The apparatus may further include a storage circuit configured to store the measurement data, and the noise control circuit may determine a frequency at which the noise is minimum based on the stored measurement data.

[0012] In the device, the measurement data may be generated and stored in advance before the touch electrode is driven by the driving signal having the first frequency.

[0013] In the device, the second frequency can be selected as a frequency with minimal noise; the driving circuit can drive the touch electrode by a driving signal having the second frequency to sense the touch or approach of an external object, and can drive the touch electrode by a driving signal having the first frequency and the third frequency to measure noise; the noise control circuit can pre-acquire measurement data related to the results of measuring the noise of the response signal having the first frequency and the third frequency; the noise control circuit can determine whether the response signal having the second frequency has noise; if the response signal having the second frequency has noise, the noise control circuit can determine the frequency with minimal noise between the first frequency and the third frequency based on the measurement data.

[0014] In the apparatus, the noise control circuit may determine that the response signal having the first frequency has noise if a noise level exceeds a threshold value.

[0015] In the device, if the response signal with the first frequency has noise, the noise control circuit may compare the noise of the response signal with the first frequency with the noise of the response signals with the second frequency and the third frequency; and if the noise of the response signal with the first frequency is less than the noise of the response signals with the second frequency and the third frequency, the noise control circuit may transmit a frequency maintaining signal to the control circuit so that the driving circuit continues to receive the driving signal with the first frequency.

[0016] In the device, the driving circuit may drive the touch electrodes using a driving signal having the first frequency to sense a touch or proximity of an external object in a first plurality of touch intervals in a frame, and may drive the touch electrodes using driving signals having the second and third frequencies, respectively, to measure noise in a second plurality of touch intervals in the frame. The noise control circuit may measure noise of a response signal having the second and third frequencies in the second plurality of touch intervals.

[0017] In the device, the driving circuit may drive the touch electrode using a driving signal having one of the second frequency and the third frequency to measure noise in the second plurality of touch intervals. The noise control circuit may measure noise at one of the second frequency and the third frequency in the second plurality of touch intervals.

[0018] In the device, a touch or proximity of a finger may be sensed in the first plurality of touch intervals or the second plurality of touch intervals.

[0019] In the apparatus, the first plurality of touch intervals and the second plurality of touch intervals may be long horizontal blanks (LHB).

[0020] On the other hand, the present invention provides a method for avoiding noise in a touch sensing device, the method comprising the following steps: driving a touch electrode by a driving signal having a first frequency for noise measurement; receiving a response signal having the first frequency in response to the driving signal having the first frequency; acquiring measurement data related to the result of measuring the noise of the response signal having the first frequency; driving the touch electrode by a driving signal having a second frequency to sense the touch or approach of an external object; judging whether the response signal to the driving signal having the second frequency has noise; and in a case where the response signal to the driving signal having the second frequency is judged to have noise, judging whether to use the driving signal having the first frequency to sense the touch or approach of the external object based on the measurement data for the first frequency.

[0021] In the method for avoiding noise, obtaining measurement data for the first frequency may be performed before determining whether a response signal to a drive signal having the second frequency has noise.

[0022] In the method for avoiding noise, a time during which the touch electrodes are driven by the driving signal having the first frequency may be shorter than a time during which the touch electrodes are driven by the driving signal having the second frequency.

[0023] In the method for avoiding noise, in a case where the touch sensing device drives the touch electrodes by the driving signal having the first frequency, at least two touch electrodes may be short-circuited and driven.

[0024] In the method for avoiding noise, the touch sensing device may drive the touch electrode by the driving signal having the second frequency in a long horizontal blanking (LHB).

[0025] On the other hand, the present invention provides a touch sensing device, comprising: a driving circuit for driving touch electrodes in frames, each frame including multiple display intervals, multiple first touch intervals and multiple second touch intervals, the driving circuit being configured to drive the touch electrodes by a first driving signal in the first touch interval, and to drive the touch electrodes by a second driving signal and a third driving signal in the second touch interval, the first driving signal, the second driving signal and the third driving signal having different frequencies; a sensing circuit being configured to sense the touch or approach of an external object by using sensing data of the touch electrodes generated corresponding to the first driving signal; and a noise control circuit being configured to change the frequency of the first driving signal to the frequency of the driving signal with less noise between the second driving signal and the third driving signal when the sensing data is judged to be noisy.

[0026] The first touch interval or the second touch interval can be arranged between two display intervals, so that the touch intervals and the display intervals are arranged alternately.

[0027] The first touch interval may correspond to a long horizontal blanking (LHB).

[0028] The second touch interval may be divided into an interval for the second driving signal and an interval for the third driving signal, and the first touch interval may be longer than the interval for the second driving signal and / or the interval for the third driving signal.

[0029] The driving circuit may drive each touch electrode individually in the first touch interval, and may short-circuit and drive at least two touch electrodes in the second touch interval.

[0030] The noise control circuit may generate noise measurement data regarding the second drive signal and the third drive signal, and may select the drive signal with less noise between the second drive signal and the third drive signal based on the noise measurement data.

[0031] The touch sensing device may further include a storage circuit for storing the noise measurement data, and the noise control circuit may determine a frequency at which the noise is minimized based on the stored noise measurement data.

[0032] The noise measurement data may be generated and stored before the touch electrode is driven by the first driving signal.

[0033] The noise control circuit may determine that the response signal from the touch electrode to the first driving signal has noise when the noise level exceeds a threshold.

[0034] The noise control circuit can compare the noise level of the first drive signal with the noise level of the second drive signal and the noise level of the third drive signal, and can maintain the frequency of the first drive signal when the noise level of the first drive signal is lower than the noise level of the second drive signal and the noise level of the third drive signal.

[0035] The touch or proximity of the finger may be sensed in the plurality of first touch intervals.

[0036] As described above, according to the present invention, data on noise levels at respective frequencies can be obtained in advance, so that the frequency of the driving signal can be changed to a frequency at which noise is minimized.

[0037] In addition, according to the present invention, the possibility that the frequency changes in a predetermined order or randomly can be prevented in advance without considering the noise level of each frequency. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] 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:

[0039] Figure 1 is a diagram showing a structure of a display device according to an embodiment;

[0040] Figure 2 is a diagram schematically illustrating a touch sensing system according to the present invention;

[0041] Figure 3 is a diagram showing the structure of a touch sensing device according to the present invention;

[0042] Figure 4 is a first flow chart of noise avoidance operations according to an embodiment;

[0043] Figure 5 is a second flow chart of noise avoidance operations according to an embodiment;

[0044] Figure 6 is a waveform diagram showing a driving signal for touch sensing according to an embodiment; and

[0045] Figure 7 2 is a waveform diagram illustrating a driving signal for touch sensing and a driving signal for noise measurement according to an embodiment. DETAILED DESCRIPTION

[0046] Figure 1 is a diagram showing a structure of a display device according to an embodiment.

[0047] refer to Figure 1 The display device 100 includes a panel 110, a data driving device 120, a gate driving device 130, a touch sensing device 140, and the like.

[0048] The panel 110 may have a plurality of data lines DL formed thereon and connected to the data driving device 120, and may have a plurality of gate lines GL formed thereon and connected to the gate driving device 130. In addition, the panel 110 may have a plurality of pixels P defined to correspond to intersections between the plurality of data lines DL and the plurality of gate lines GL, respectively.

[0049] A transistor may be formed at each pixel P in such a manner that a first electrode (eg, source electrode or drain electrode) is connected to the data line DL, a gate electrode is connected to the gate line GL, and a second electrode (eg, drain electrode or source electrode) is connected to the display electrode.

[0050] In addition, the panel 110 may have a plurality of touch electrodes TE additionally formed thereon and spaced apart from each other. One pixel P or a plurality of pixels P may be located in the region where the touch electrode TE is located.

[0051] The panel 110 may include a display panel and a touch screen panel (TSP), and the display panel and the TSP may share some components with each other. For example, a plurality of touch electrodes TE may constitute a component of the display panel (e.g., a common electrode for applying a common voltage) and may also constitute a component of the TSP (a touch electrode for sensing touch). Considering that the display panel and the TSP share some components with each other, such a panel 110 may be referred to as an integrated panel, but the present invention is not limited thereto. In addition, a panel within a unit is known as a panel of this type (including a display panel and a TSP that share some components with each other), but is only an example of the above-mentioned panel 110, and the type of panel to which the present invention is applied is not limited to the panel within the unit.

[0052] The data driving device 120 is configured to supply data signals through the data lines DL so that the respective pixels P display images.

[0053] The data driving device 120 may include at least one data driver integrated circuit. The at least one data driver integrated circuit may be connected to a bonding pad of the panel 110 in a tape automated bonding (TAB) type or a chip on glass (COG) type, or may be directly formed on the panel 110. If necessary, the data driving device 120 may be formed to be integrated with the panel 110. In addition, the data driving device 120 may be implemented in a chip on film (COF) type.

[0054] The gate driving device 130 is configured to sequentially supply scan signals through the gate lines GL to turn on or off transistors in the respective pixels P.

[0055] Depending on the driving scheme, 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 130 may be located on both sides of the panel 110 .

[0056] In addition, the gate driver 130 may include at least one gate driver integrated circuit. The at least one gate driver integrated circuit may be connected to the bonding pad of the panel 110 in a TAB type or a COG type. Alternatively, the gate driver 130 may be implemented in a gate-in-panel (GIP) type and formed directly on the panel 110. If necessary, the gate driver 130 may be formed to be integrated with the panel 110. In addition, the gate driver 130 may be implemented in a COF type.

[0057] The touch sensing device 140 is configured to apply a driving signal to all or a portion of the plurality of touch electrodes TE connected to the sensing line SL.

[0058] As shown in the figure, the touch sensing device 140 can be configured separately from the data driving device 120 and the gate driving device 130 and located outside the data driving device 120 and the gate driving device 130. Depending on the implementation, the touch sensing device 140 can also be configured as an internal component of a separate driver integrated circuit that includes at least one of the data driving device 120 and the gate driving device 130. Alternatively, the touch sensing device 140 can be configured as an internal component of the data driving device 120 or the gate driving device 130.

[0059] Therefore, the description that the touch sensing device 140 applies a driving signal to all or part of the plurality of touch electrodes TE may also be considered to include the meaning that a separate driver integrated circuit of the touch sensing device 140 applies a driving signal to all or part of the plurality of touch electrodes TE. In addition, depending on the design solution, the description may also be considered to include the meaning that the data driving device 120 or the gate driving device 130 of the touch sensing device 140 applies a driving signal to all or part of the plurality of touch electrodes TE.

[0060] The touch sensing device 140 is not limited in any way in terms of how it is implemented and designed. The touch sensing device 140 may be a separate component itself or a component located inside or outside a separate component, as long as it performs the same or similar functions as those described herein.

[0061] In addition, although one touch sensing device 140 is illustrated as being located in the display device 100 in the drawing, the display device 100 may include two or more touch sensing devices 140 .

[0062] On the other hand, in order for the touch sensing device 140 to apply a driving signal to all or part of the plurality of touch electrodes TE, the sensing lines SL need to be connected to the plurality of touch electrodes TE. Therefore, the sensing lines SL may be formed on the panel 110 in a first direction (e.g., a vertical direction) or in a second direction (e.g., a horizontal direction) and connected to the plurality of touch electrodes TE to transmit the driving signal.

[0063] On the other hand, the display device 100 may adopt a capacitive touch scheme, so that the approach or touch of an external object can be recognized by detecting a change in capacitance through the touch electrode TE.

[0064] Such capacitive touch schemes may be classified into, for example, a mutual capacitance touch scheme and a self capacitance touch scheme.

[0065] According to the mutual capacitive touch scheme, which is a capacitive touch scheme, a driving signal is applied to a touch electrode (Tx electrode), and another touch electrode (Rx electrode) mutually coupled with the Tx electrode is sensed. According to the mutual capacitive touch scheme, since the value sensed at the Rx electrode changes according to the approach or touch of an external object such as a finger or a pen, the value sensed at the Rx electrode can be used to detect the presence of a touch or obtain touch coordinates.

[0066] According to the self-capacitive touch scheme, which is another capacitive touch scheme, a drive signal is applied to the touch electrode TE, and the touch electrode TE is sensed again. According to the self-capacitive touch scheme, since the value sensed in the touch electrode TE changes according to the approach or touch of an external object such as a finger or a pen, such a value can be used to detect the presence of a touch or obtain touch coordinates. In the self-capacitive touch scheme, the touch electrode TE to which the drive signal is applied is the same as the touch electrode TE to which the sense is applied, that is, there is no distinction between the Tx electrode and the Rx electrode.

[0067] The display device 100 may adopt one of the two capacitive touch schemes (mutual capacitive touch scheme and self-capacitive touch scheme). In the following description of the embodiment, for ease of description, it will be assumed that the self-capacitive touch scheme is adopted.

[0068] On the other hand, the display device 100 can distinguish between the display interval and the touch interval and drive the touch electrodes TE accordingly. 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 in the interval of supplying data signals.

[0069] In addition, the display device 100 can drive the touch electrodes TE without distinguishing between display intervals and touch intervals. For example, the touch sensing device 140 of the display device 100 can apply a driving signal to all or part of the touch electrodes TE in an interval in which a data signal is supplied.

[0070] Figure 2 is a diagram schematically illustrating a touch sensing system according to the present invention.

[0071] refer to Figure 2 , the touch sensing system 200 may include a panel 110 and a touch sensing device 140 .

[0072] The panel 110 may have a plurality of touch electrodes TE arranged thereon.

[0073] The touch sensing device 140 may supply a driving signal STX to the touch electrode TE. The driving signal STX may be a voltage type or current type signal, and the voltage type driving signal STX may be defined as a driving voltage. The driving signal may include a driving period having a first period and a second period.

[0074] The touch sensing device 140 may receive a response signal SRX related to the driving signal STX from the touch electrode TE and may demodulate the response signal SRX, thereby sensing the touch or proximity of the object 10 to the panel 110. The response signal SRX may be a current type or voltage type signal.

[0075] Figure 3 is a diagram showing the structure of a touch sensing device according to the present invention.

[0076] refer to Figure 3 The touch sensing device 140 may include a driving circuit 310 , a sensing circuit 320 , a noise control circuit 330 , a control circuit 340 , and a storage circuit 350 .

[0077] The driving circuit 310 can supply a driving signal STX having a certain frequency to the touch electrode TE. The driving circuit 310 can drive the touch electrode using driving signals STX having different frequencies depending on the function. For example, the driving circuit 310 can drive the touch electrode using a driving signal STX having a first frequency to sense the touch or proximity of an external object. The driving circuit 310 can also drive the touch electrode using a driving signal STX having a second frequency and a driving signal STX having a third frequency to measure noise.

[0078] The sensing circuit 320 may receive a response signal SRX related to the drive signal STX from the touch electrode TE. The sensing circuit 320 may receive a response signal SRX having different frequencies depending on the function and corresponding to the drive signal STX. For example, the sensing circuit 320 may receive a response signal SRX having a first frequency to sense the touch or proximity of an external object. The sensing circuit 320 may receive a response signal SRX having a second frequency and a response signal SRX having a third frequency to measure noise.

[0079] The sensing circuit 320 may sense a touch or proximity of an external object to the panel based on the response signal SRX, and may generate sensing data based on the response signal SRX.

[0080] The sensing data may include a sensed value obtained by demodulating the response signal SRX. For example, the sensed value may be a time-integrated value of the current or voltage of the response signal SRX. The sensed value may be used to determine whether an object has touched the touch panel or to obtain touch coordinates. For example, if the sensed value is greater than or less than a reference value, it may be determined that an external object has touched the touch panel.

[0081] The noise control circuit 330 can measure the noise of the frequency used for noise measurement and generate measurement data related to the measurement result. If the noise control circuit 330 determines that the current frequency of the drive signal STX is noisy, the noise control circuit 330 can determine the frequency with the minimum noise based on the measurement data and control the control circuit 340 to drive the touch electrode with the drive signal having the selected frequency.

[0082] Specifically, the noise control circuit 330 can receive a response signal SRX having a second frequency and a response signal SRX having a third frequency from the sensing circuit 320 to perform noise measurement. The noise control circuit 330 can measure the noise of the response signal SRX having the second frequency and the response signal SRX having the third frequency, and can generate measurement data related to the measurement results. The noise control circuit 330 can store the measurement data in the storage circuit 350. The noise control circuit 330 can generate and store the measurement data when the first frequency is used as the drive signal STX, or can generate and store the measurement data in advance before the first frequency is used as the drive signal STX. The noise control circuit 330 can pre-measure the noise levels related to the second frequency and the third frequency, thereby identifying the noise state to prevent possible interference from the noise in the drive signal STX having the first frequency.

[0083] Afterwards, the noise control circuit 330 may determine whether the first frequency currently used to drive the touch electrodes has noise. If the noise level of the driving signal STX with the first frequency exceeds a threshold, the noise control circuit 330 may determine that the driving signal STX has noise.

[0084] If the currently used first frequency has noise, the noise control circuit 330 may determine the frequency with the least noise between the second frequency and the third frequency based on the measurement data. The noise control circuit 330 may retrieve the measurement data stored in the storage circuit 350 and select one of the second frequency and the third frequency from the retrieved data as a frequency to replace the first frequency.

[0085] If the current frequency used to drive the touch electrodes is noisy, the noise control circuit 330 may send a frequency change signal to the control circuit 340 to supply a drive signal STX having a different frequency. For example, if the frequency with the least noise is selected as the second frequency, the noise control circuit 330 may generate a frequency change signal instructing to change the frequency of the drive signal STX from the first frequency to the second frequency, and may send the frequency change signal to the control circuit 340. The control circuit 340 may supply the drive signal STX having the second frequency to the drive circuit 310.

[0086] If the drive signal STX having a frequency is noisy, and if the frequency is replaced with another frequency accordingly, the noise control circuit 330 can measure the noise associated with the replaced frequency. For example, if the drive signal STX having a first frequency has been driving the touch electrode, and if the first frequency is replaced with a second frequency, the noise control circuit 330 can measure the noise associated with the response signal SRX having the first frequency and the response signal SRX having a third frequency. The noise control circuit 330 can store the results of measuring the noise of the first and third frequencies in the storage circuit 350. The noise of the first and third frequencies can be measured when the drive signal STX having the second frequency drives the touch electrode. That is, the noise of the first and third frequencies can be measured in the partial touch interval where the driving of the touch electrode is suspended.

[0087] On the other hand, even if the current frequency used to drive the touch electrodes is noisy, instead of sending a frequency change signal, the noise control circuit 330 may send a frequency maintenance signal to maintain the drive signal STX having the current frequency. For example, if the response signal SRX having a first frequency is noisy, the noise control circuit 330 may compare the noise level of the first frequency with the noise levels of the second frequency and the noise levels of the third frequency. If the noise level of the first frequency is lower than the noise levels of the second frequency and the third frequency, the noise control circuit 330 may determine to maintain the drive signal STX having the first frequency. The noise control circuit 330 may send a frequency maintenance signal including information instructing to maintain the drive signal STX having the first frequency to the control circuit 340.

[0088] The control circuit 340 may supply the drive signal STX to the drive circuit 310. If the control circuit 340 receives a request (frequency change signal) from the noise control circuit 330 to change the frequency of the drive signal STX, the control circuit 340 may generate a drive signal STX having a frequency that complies with the request and may supply the drive signal STX to the drive circuit 310. For example, if a frequency with minimal noise is selected as the second frequency, the control circuit 340 may generate a drive signal STX having the second frequency and may send the drive signal STX to the drive circuit 310. The drive circuit 310 may then drive the touch electrode using the drive signal STX having the second frequency instead of the first frequency.

[0089] The control circuit 340 may generate a control signal CS to control 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 may operate according to the control signal CS.

[0090] The storage circuit 350 may store the results of measuring noise at the frequencies used for noise measurement. For example, if a driving signal STX having a first frequency is currently used to drive the touch electrode, the results of measuring noise at the second and third frequencies may be stored in the storage circuit 350. If the first frequency is noisy, and if the driving signal STX having the second frequency is correspondingly used to drive the touch electrode, the results of measuring noise at the first and third frequencies may be stored in the storage circuit 350 again.

[0091] On the other hand, the touch panel may include multiple touch electrodes. During the touch electrode driving period for noise measurement, the touch sensing device 140 may concurrently drive the multiple touch electrodes. To this end, the touch sensing device 140 may further include a mux (multiplexer) (not shown).

[0092] A mux can be provided in each channel including the drive circuit 310 and the sensing circuit 320. The mux can short-circuit each touch electrode. If the multiplexer does not short-circuit each touch electrode, one channel drives the touch electrode individually through the drive circuit 310 and the sensing circuit 320. However, if the mux drives each touch electrode, one channel can drive multiple touch electrodes concurrently. This concurrent driving can be performed at the frequency used for noise measurement. The touch sensing device 140 can simultaneously send a drive signal STX having the frequency used for noise measurement to multiple touch electrodes and can receive response signals SRX to these drive signals STX. The touch sensing device 140 can measure the noise of the response signals SRX.

[0093] Figure 4is a first flow chart of noise avoidance operations according to an embodiment.

[0094] refer to Figure 4 The touch sensing device of the display device according to the embodiment can obtain the following data in advance. This data is obtained by measuring noise at different frequencies when the touch electrode is driven at the current frequency. If noise interferes with the current frequency, the touch sensing device can determine the frequency with the lowest noise based on this data and replace the frequency of the driving signal with the determined frequency.

[0095] The driving circuit may drive the touch electrode by a driving signal for noise measurement having a first frequency and a second frequency ( S402 ).

[0096] The noise control circuit can measure the noise of the first frequency and the second frequency, and can store measurement data related to the results of measuring the noise of the first frequency and the second frequency in the storage circuit (S404). The noise control circuit can receive response signals having the first frequency and the second frequency from the sensing circuit and can measure the noise levels of these response signals.

[0097] For touch sensing, the driving circuit may drive the touch electrode by a driving signal having a third frequency ( S406 ).

[0098] The noise control circuit may measure noise of the third frequency ( S408 ).

[0099] The noise control circuit may compare the noise level of the third frequency with a threshold value ( S410 ).

[0100] If the noise level of the third frequency is not higher than the threshold, the noise control circuit may repeatedly measure the noise of the third frequency (“No” in S410 ).

[0101] If the noise level of the third frequency is higher than the threshold ("Yes" in S410), the noise control circuit may select one of the first frequency and the second frequency (S412). The noise control circuit may read the stored measurement data and, based on the measurement data, may select the frequency with the lowest noise level between the first frequency and the second frequency.

[0102] The driving circuit may drive the touch electrode using a driving signal having the selected frequency (S414). The noise control circuit may send a signal to the control circuit to change the frequency of the driving signal from the third frequency to a frequency with the lowest noise level. The control circuit may generate a driving signal having a frequency with the lowest noise level and send the driving signal to the driving circuit.

[0103] Figure 5 is a second flow chart of noise avoidance operation according to an embodiment.

[0104] refer to Figure 5 According to an embodiment, if noise of another frequency is greater than noise of a current frequency of a driving signal, a touch sensing device of a display device may not change the driving signal to have the another frequency.

[0105] The noise control circuit may measure noise of a first frequency and a second frequency, and may store measurement data related to a result of measuring the noise in a storage circuit ( S502 ).

[0106] For touch sensing, the driving circuit may drive the touch electrode by a driving signal having a third frequency ( S504 ).

[0107] The noise control circuit may measure noise of a third frequency ( S506 ).

[0108] The noise control circuit may compare the noise level of the third frequency with a threshold value ( S508 ).

[0109] If the noise level of the third frequency is not higher than the threshold, the noise control circuit may continue to measure the noise of the third frequency (“No” in S508 ).

[0110] If the noise level of the third frequency is higher than the threshold (YES in S508 ), the noise control circuit may compare the noise level of the third frequency with the noise levels of the first and second frequencies ( S510 ).

[0111] If the noise level of the third frequency is not higher than the noise levels of the first and second frequencies, the noise control circuit may repeat measuring the noise of the third frequency (“No” in S510 ).

[0112] If the noise level of the third frequency is higher than the noise levels of the first frequency and the second frequency (“Yes” in S510 ), the noise control circuit may select one of the first frequency and the second frequency ( S512 ).

[0113] The driving circuit may drive the touch electrode by the driving signal having the selected frequency ( S514 ).

[0114] Figure 6 is a waveform diagram illustrating a driving signal for touch sensing according to an embodiment.

[0115] Figure 6 1 and 2. A synchronization signal SYNC for instructing the display device to perform a display operation and a touch operation on a time-division basis, and a drive signal STX for driving the touch electrode according to the synchronization signal SYNC are shown.

[0116] The synchronization signal SYNC may include a display interval D for adjusting display operations and a touch interval T for adjusting touch operations. This display and touch operation may be performed in a first type, in which all lines of the display panel are scanned in a single frame before the touch panel is sensed, or in a second type, in which scanning of specific lines of the display panel and sensing of the touch panel are repeated in a single frame. The second type, in which display and touch operations are repeated in a single frame, will be described below. Each touch interval T in the second type may be referred to as a long horizontal blanking (LHB).

[0117] The synchronization signal SYNC may include multiple display intervals D and multiple touch intervals T (multiple LHBs) in each frame. In this figure, the synchronization signal SYNC may include 16 display intervals D and 16 touch intervals T in one frame. The touch intervals T may be labeled T1-T16.

[0118] The driving circuit can drive the touch electrodes to sense the touch or proximity of an external object in multiple touch intervals of a frame. For example, the driving circuit can drive the touch electrodes in multiple touch intervals T1-T4 and T9-T12 using a driving signal STX having a first frequency f1. The multiple touch intervals T1-T4 and T9-T12 for sensing the touch or proximity of an external object can be positioned adjacent to each other. Alternatively, as shown in the figure, the multiple touch intervals T1-T4 and T9-T12 can be configured so that a group of touch intervals are positioned to be spaced apart from each other.

[0119] Figure 7 2 is a waveform diagram illustrating a driving signal for touch sensing and a driving signal for noise measurement according to an embodiment.

[0120] Figure 7 A driving signal STX for sensing the touch or proximity of an external object and a driving signal STX for noise measurement are shown.

[0121] The driving circuit may drive the touch electrodes to sense the touch or proximity of an external object in a plurality of touch intervals of one frame, and on the other hand, may drive the touch electrodes to measure noise in other plurality of touch intervals.

[0122] For example, the driving circuit may drive the touch electrodes by a driving signal STX having a first frequency f1 in the first multiple touch intervals T1-T4 and T9-T12, and on the other hand, may drive the touch electrodes by a driving signal STX having a second frequency f2 or a driving signal STX having a third frequency f3 in the second multiple touch intervals T5, T6, T13, and T14.

[0123] The second frequency f2 and the third frequency f3 may be different from the first frequency f1. The second frequency f2 may be greater than the first frequency f1, and the third frequency f3 may be less than the first frequency f1.

[0124] The second plurality of touch intervals T5, T6, T13, and T14 for noise measurement can be positioned adjacent to each other. Alternatively, as shown in the figure, the plurality of touch intervals T1-T4 and T9-T12 can be configured so that a group of touch intervals are positioned spaced apart from each other. The positions and combinations of the touch intervals used only for sensing the touch or proximity of an external object and the touch intervals used for noise measurement are not limited thereto and can be configured in various ways.

[0125] In this regard, each touch interval may correspond to a time period during which a touch or proximity of a stylus or finger is sensed. Thus, a first plurality of touch intervals T1-T4 and T9-T12 may be designated for sensing a finger, and a second plurality of touch intervals T5, T6, T13, and T14 may be designated for sensing a stylus.

[0126] In this case, noise measurement and sensing of the touch or proximity of an external object can be performed simultaneously in the second plurality of touch intervals T5, T6, T13, and T14. For example, noise of the third frequency f3 can be measured in a portion of touch interval T13, and the touch or proximity of the stylus can be sensed in the remaining portion of touch interval T13. The arrangement and combination of touch intervals for sensing only the touch or proximity of an external object and touch intervals for measuring noise are not limited thereto and can be set in various ways.

[0127] CROSS-REFERENCE TO RELATED APPLICATIONS

[0128] This application claims priority to Korean Patent Application No. 10-2019-0173696, filed on December 24, 2019, which is hereby incorporated by reference for all purposes as if fully set forth herein.

Claims

1. A touch sensing device, comprising: a driving circuit configured to drive the touch electrodes in frames, each frame comprising a plurality of display intervals, a plurality of first touch intervals, and a plurality of second touch intervals, the driving circuit being configured to drive the touch electrodes using a first driving signal in the first touch intervals, and to drive the touch electrodes using a second driving signal and a third driving signal in the second touch intervals, the first driving signal, the second driving signal, and the third driving signal having different frequencies; a sensing circuit configured to sense a touch or proximity of an external object by using sensing data of the touch electrode generated corresponding to the first driving signal; as well as The noise control circuit is configured to change the frequency of the first drive signal to a frequency of the drive signal with less noise among the second drive signal and the third drive signal when the sensing data is determined to have noise.

2. The touch sensing device according to claim 1, wherein: The first touch interval or the second touch interval is arranged between two display intervals, so that the touch intervals and the display intervals are alternately arranged.

3. The touch sensing device according to claim 2, wherein: The first touch interval corresponds to a long horizontal blanking (LHB).

4. The touch sensing device according to claim 1, wherein: The second touch interval is divided into an interval for the second drive signal and an interval for the third drive signal, and the first touch interval is longer than the interval for the second drive signal and / or the interval for the third drive signal.

5. The touch sensing device according to claim 4, wherein: The driving circuit is configured to drive each touch electrode individually in the first touch interval, and is configured to short-circuit and drive at least two touch electrodes in the second touch interval. The touch sensing device according to claim 1 , wherein: The noise control circuit is configured to generate noise measurement data related to the second drive signal and the third drive signal, and is configured to select a drive signal with less noise between the second drive signal and the third drive signal based on the noise measurement data. 7 . The touch sensing device according to claim 6 , further comprising a storage circuit in which the noise measurement data is stored, and the noise control circuit is configured to determine a frequency at which noise is minimized based on the stored noise measurement data.

8. The touch sensing device according to claim 6, wherein: The noise measurement data is generated and stored before the touch electrode is driven by the first driving signal.

9. The touch sensing device according to claim 1, wherein: The noise control circuit is configured to determine that a response signal from the touch electrode to the first drive signal has noise when a noise level exceeds a threshold.

10. The touch sensing device according to claim 2, wherein: The noise control circuit is configured to compare the noise level of the first drive signal with the noise levels of the second drive signal and the third drive signal, and maintain the frequency of the first drive signal if the noise level of the first drive signal is lower than the noise level of the second drive signal and the noise level of the third drive signal.

11. The touch sensing device according to claim 1, wherein: A touch or proximity of a finger is sensed in the plurality of first touch intervals.

12. A method for avoiding noise in a touch sensing device, the method comprising: driving the touch electrode by a driving signal for noise measurement having a first frequency; receiving a response signal having the first frequency in response to a drive signal having the first frequency; acquiring measurement data related to a result of measuring noise of a response signal having the first frequency; driving the touch electrodes by a driving signal having a second frequency to sense a touch or proximity of an external object; determining whether a response signal to the driving signal having the second frequency has noise; as well as If it is determined that the response signal to the driving signal having the second frequency has noise, it is determined based on the measurement data for the first frequency whether to use the driving signal having the first frequency to sense the touch or proximity of the external object.

13. The method according to claim 12, wherein: A time during which the touch electrodes are driven by the driving signal having the first frequency is shorter than a time during which the touch electrodes are driven by the driving signal having the second frequency.

14. The method according to claim 13, wherein In driving of the touch electrodes by the driving signal having the first frequency, at least two touch electrodes are short-circuited and driven.

15. The method according to claim 12, wherein: The touch electrodes are driven by the driving signal having the second frequency in a long horizontal blanking (LHB).

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