KR20140068532A - Electronic device having a touch sensor and driving method thereof - Google Patents

Abstract

The present invention provides an electronic device which comprises touch sensors; a first noise reduction unit which receives touch raw data when a touch occurs on the touch sensors, detects an actual touch having a level more than a correction threshold and on-axis noise from the touch raw data, and removes the on-axis noise; a second noise reduction unit which detects an actual touch having a level more than a correction threshold and impulse noise, and amplifies the actual touch and the impulse noise to remove impulse noise having a low level compared to a touch threshold; and a coordinate calculating unit which gives an identification number to the touch raw data from which the on-axis noise and the impulse noise are removed, and calculates coordinates of a touch input position.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an electronic device having a touch sensor,

The present invention relates to an electronic device having a touch sensor and a driving method thereof.

Various electronic devices, such as household appliances and portable information devices, have been replaced by touch sensors in a button-type switch in accordance with the trend of weight reduction and slimness. Accordingly, an electronic device such as a display device or the like that has recently been introduced has a touch sensor (or a touch screen).

One of the touch sensors, the capacitive touch sensor, senses a change in mutual capacitance when a human finger or a conductive material touches or approaches, thereby recognizing presence or absence of touch and coordinates. In this case, in order to measure the change of the mutual capacitance and determine the information about the touch, it is necessary to set each sensor node of the touch screen panel, to output a driving signal, to sense the mutual capacitance change of the touch screen panel, .

The capacitance type senses the mutual capacitance converted by human finger or conductive material and classifies it into touch only when the peak level of the sensed signal is above the threshold value and submits the touch report to it.

However, in the conventional capacitance method, when a user performs multi-touch, a ghost touch (hereinafter referred to as ghost noise) occurs in an area other than the touch point. The ghost noise occurs in an area intersecting the touch point or in an area adjacent to the touch point. Since such a ghost noise lowers the recognition rate of the touch, an electronic device having a conventional touch sensor is required to eliminate ghost noise.

In order to solve the above problems, the present invention provides an electronic device having a touch sensor capable of improving a touch recognition rate at the time of multi-touch operation and improving a function of acquisition, linearity and papillization of a touch, Method.

According to an aspect of the present invention, A first noise removing unit that receives touch raw data when a touch occurs in the touch sensors and detects an actual touch and an axial noise having a level equal to or higher than a correction threshold value in the touch raw data and removes the axial noise; A second noise eliminator for detecting an impulse noise and a real touch having a level equal to or higher than a correction threshold value and amplifying an impulse noise and an actual touch to remove an impulsive noise having a lower level than a touch threshold value; And a coordinate calculator for assigning an identification number to the touch raw data from which the axial noise and the impulsive noise are removed and calculating coordinates for the touch input position.

The first noise removing unit can discriminate and remove flat data having no change in inclination over a certain node as axial noise.

The first noise canceller analyzes the waveform connection relation of three or more nodes with respect to the data exceeding the correction threshold value and discriminates the tilt data having the gradient change of three or more nodes as the actual touch while the flat data having no change of the tilt is referred to as axial noise Can be distinguished.

The second noise removing unit may perform upward correction of the baseline when actual touch and impulsive noise are detected, and clipping a level lower than the baseline corrected upward in the actual touch and impulsive noise.

The second noise eliminator amplifies the actual touch and the impulsive noise, sets the touch threshold at a level between the peak level of the upwardly corrected baseline and the actual touch, and removes the impulsive noise having a lower level than the touch threshold can do.

When the actual touch of the touch original data obtained through one Tx line is received in a form of gradually decreasing, the coordinate calculation unit calculates a correction coefficient based on the decrease slope of the touch original data by the position, multiplies the touch original data by a correction coefficient Can be averaged.

In another aspect, the present invention provides a method comprising: receiving touch raw data; Determining whether or not there is data exceeding a correction threshold value in the touch raw data; Detecting an actual touch and an axial noise having a level equal to or higher than a correction threshold value, and removing axial noise; Detecting an impulse noise and an actual touch having a level equal to or higher than a correction threshold value and amplifying an impulse noise and an actual touch to remove an impulsive noise having a lower level than a touch threshold value; And assigning an identification number to the touch raw data from which the axial noise and the impulsive noise are removed, and calculating coordinates for the touch input position.

In the step of removing the axial noise, flat data having no change in gradient over a certain node can be discriminated and removed as axial noise.

In the step of removing the axial noise, the waveform connection relation of three or more nodes is analyzed with respect to the data over the correction threshold value, and the tilt data with the change of the tilt of three or more nodes is discriminated by the actual touch, It can be discriminated by noise.

The step of removing the impulsive noise may perform climbing of a level lower than the base line which is up-corrected in the actual touch and the impulsive noise by up-correcting the baseline when actual touch and impulsive noise are detected.

The step of removing the impulsive noise amplifies the actual touch and the impulsive noise, sets the touch threshold to a level between the peak level of the upwardly corrected baseline and the actual touch, Noise can be removed.

When the actual touch of the touch original data obtained through one Tx line is received in a form of gradually decreasing, the coordinate calculation unit calculates a correction coefficient based on the decrease slope of the touch original data by the position, multiplies the touch original data by a correction coefficient Can be averaged.

The present invention provides an electronic device having a touch sensor capable of enhancing a signal-to-noise ratio (SNR) by removing mutual ghost noise and improving a touch recognition rate in a multi-touch operation, and a driving method thereof. In addition, the present invention provides an electronic device having a touch sensor capable of improving the uniformity of touch source data and improving the functions of acquiring, linearizing, and pausing the touch, and a driving method thereof.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is an illustration of an electronic device having a touch sensor according to an embodiment of the present invention.
2 is an equivalent circuit diagram of the touch screen shown in Fig.
3 to 5 are views showing various combinations of a liquid crystal display panel and a touch screen.
Figs. 6 and 7 are diagrams for explaining ghost noise. Fig.
8 is a flowchart illustrating a method of controlling a touch screen according to the present invention.
Figs. 9 to 15 are illustrations of removal of the ghost noise described in Fig. 8. Fig.
Figures 16-18 are illustrations of a method for improving the uniformity of touch primitive data.
19 is a modification of the first to third data correction methods;

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 is an equivalent circuit diagram of the touch screen shown in FIG. 1, and FIGS. 3 to 5 are diagrams showing an example of an electronic device having a touch sensor according to an embodiment of the present invention. FIG. 6 and FIG. 7 are views for explaining ghost noise. FIG.

The electronic device having the touch sensor of the present invention is implemented as a television, a set-top box, a navigation device, a video player, a Blu-ray player, a personal computer (PC), a home theater and a mobile phone. An electronic device having a touch sensor of the present invention is implemented based on a display panel. The display panel may be a flat panel display panel such as a liquid crystal display panel, an organic light emitting display panel, an electrophoretic display panel, or a plasma display panel, but is not limited thereto. However, in the following description, a liquid crystal display panel will be described as an example for convenience of explanation.

The electronic device having the touch sensor includes a host system 50, a timing controller 20, a data driving circuit 12, a scan driving circuit 14, a liquid crystal display panel DIS, a touch screen TSP, (30, 40).

The host system 50 includes a system on chip (SoC) with a built-in scaler, which converts the digital video data RGB of the input image into a format suitable for display on the display panel DIS. The host system 50 transmits timing signals (Vsync, Hsync, DE, MCLK) to the timing controller 20 together with the digital video data. The host system 50 executes the application program associated with the coordinate information XY of the touch input position input from the touch coordinate detection unit 40. [

The timing controller 20 receives timing signals such as a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DE and a main clock MCLK from the host system 50, And controls the data driving circuit 12 and the scan driving circuit 14 on the basis thereof.

The timing controller 20 generates a scan timing control signal based on a scan timing control signal such as a gate start pulse (GST), a gate shift clock, and a gate output enable (GOE) (14). The timing controller 20 generates a timing control signal based on a data timing control signal such as a source sampling clock (SSC), a polarity control signal (POL), and a source output enable (SOE) (12).

The data driving circuit 12 converts the digital video data RGB input from the timing controller 20 into an analog positive / negative gamma compensation voltage to generate a data voltage. The data driving circuit 12 supplies the data voltage through the data lines D1 to Dm.

The scan driving circuit 14 sequentially generates gate pulses (or scan pulses) synchronized with the data voltage. The scan driver circuit 14 supplies gate pulses through the gate lines G1 to Gn.

The liquid crystal display panel DIS displays an image based on the gate pulse supplied from the scan driving circuit 14 and the data voltage supplied from the data driving circuit 12. [ The liquid crystal display panel DIS includes a liquid crystal layer formed between two substrates GLS1 and GLS2. The liquid crystal display panel DIS may be implemented in any known liquid crystal mode such as TN (Twisted Nematic) mode, VA (Vertical Alignment) mode, IPS (In Plane Switching) mode and FFS (Fringe Field Switching) mode.

The subpixels of the liquid crystal display panel DIS are defined by the data lines (D1 to Dm, m is a positive integer) and the gate lines (G1 to Gn, n are positive integers). One subpixel includes a TFT (Thin Film Transistor) formed at the intersections of the data line and the gate line, a pixel electrode for charging the data voltage, a storage capacitor Cst connected to the pixel electrode for maintaining the voltage of the liquid crystal cell ) And the like.

A black matrix, a color filter and the like are formed on the upper substrate GLS1 of the liquid crystal display panel DIS. The lower substrate GLS2 of the liquid crystal display panel DIS may be implemented with a color filter on TFT (COT) structure. In this case, the black matrix and the color filter can be formed on the lower substrate GLS2 of the liquid crystal display panel DIS. The common electrode to which the common voltage is supplied may be formed on the upper substrate GLS1 or the lower substrate GLS2 of the liquid crystal display panel DIS. Polarizing plates POL1 and POL2 are attached to the upper substrate GLS1 and the lower substrate GLS2 of the liquid crystal display panel DIS and an alignment film for setting the pretilt angle of the liquid crystal on the inner surface in contact with the liquid crystal is formed.

A column spacer for maintaining a cell gap of the liquid crystal cell is formed between the upper substrate GLS1 and the lower substrate GLS2 of the liquid crystal display panel DIS. A backlight unit is disposed below the bottom surface of the lower polarizer plate POL2 of the liquid crystal display panel DIS. The backlight unit is implemented as an edge type or direct type to provide light to the liquid crystal display panel (DIS).

The touch screen TSP includes Tx lines (Tx1 to Txj, j is a positive integer smaller than n), Rx lines Rx1 to Rxi, i, which intersect with Tx lines Tx1 to Txj, And ix j number of touch sensors Cts formed at intersections of the Tx lines Tx1 to Txj and the Rx lines Rx1 to Rxi. Each of the touch sensors Cts includes a capacitance in view of an equivalent circuit.

Capacitance can be divided into self capacitance and mutual capacitance. The self-capacitance is formed along a conductor wiring of a single layer formed in one direction. The mutual capacitance is formed between two orthogonal conductor wirings. In the embodiment, the mutual capacitance type touch screen is illustrated, but the present invention is not limited thereto.

The touch screen TSP may be disposed on the upper polarizer POL1 of the liquid crystal display panel DIS as shown in FIG. The touch screen TSP may be disposed between the upper polarizer POL1 and the upper substrate GLS1 of the liquid crystal display panel DIS as shown in FIG. The touch screen TSP may be embodied such that the pixel electrode PIX of the lower substrate GLS2 and the touch sensor Cts are positioned together so as to be embedded in the liquid crystal display panel DIS as shown in FIG.

The touch screen driving circuits 30 and 40 supply a driving signal to the touch sensors Cts to sense a voltage change of the touch sensor before and after the touch input, compare the voltage change with a predetermined touch threshold value, . The touch screen drive circuits 30 and 40 calculate the coordinates of the touch input position.

The touch sensing circuit 30 includes a Tx driving circuit 32, an Rx driving circuit 34, a Tx / Rx controller 38, and the like. The touch sensing circuit 30 applies a driving signal to the touch sensors Cts through the Tx lines Tx1 to Txj using the Tx driving circuit 32 and applies the driving signals to the Rx lines Rx1 to Rx, Rxi) and the Rx driving circuit 34 to output touch raw data. The driving signal may be formed in various forms such as a pulse, a sinusoidal wave, and a triangular wave. The touch sensing circuit 30 may be integrated into one ROIC (read-out integrated circuit).

The Tx driving circuit 32 selects a Tx channel to output a driving signal in response to a Tx setup signal from the Tx / Rx controller 38 and outputs a driving signal to the Tx lines Tx1 to Txj connected to the selected Tx channel . The Tx lines Tx1 to Txj are charged during the high potential interval of the driving signal to supply charges to the touch sensors Cts. The driving signal is supplied to the Tx lines Tx1 to Txj through the Rx lines Rx1 to Rxi so that the voltage of the touch sensors Cts can be accumulated in the capacitors of the integrator built in the Rx driving circuit 34. [ N (N is a positive integer equal to or more than) can be continuously supplied to each of them.

The Rx driving circuit 34 selects Rx lines to receive the voltage of the touch sensor in response to the Rx set-up signal from the Tx / Rx controller 38 and outputs the touch sensor Cts through the selected Rx lines in synchronization with the driving signal. And samples it. Then, the Rx drive circuit 34 accumulates the sampled voltage in the capacitor of the integrator, converts the voltage of the capacitor to digital data using an analog-to-digital converter (ADC) And outputs the digital data as touch raw data.

The Tx / Rx controller 38 controls the Tx and Rx channel settings in response to the Tx setup signal and the Rx setup signal from the touch coordinate detector 40 and synchronizes the Tx driver 32 and the Rx driver 34.

The touch coordinate detecting unit 40 includes a first noise removing unit 42, a second noise removing unit 44, a coordinate calculating unit 46, and the like. The touch coordinate detector 40 supplies a Tx setup signal and an Rx setup signal to the Tx / Rx controller 38 and an ADC clock signal for operating the ADC of the Rx driver circuit 34 to the Rx driver circuit 34 .

The coordinate calculation unit 46 calculates the coordinates of the touch data from which the noise component is removed. The coordinate calculation unit 46 compares the touch raw data received via the first noise remover 42 and the second noise remover 44 with a preset touch threshold value. The touch coordinate detection unit 40 judges that the touch data obtained from the touch sensors Cts only exceeds the touch threshold value among the touch source data.

The coordinate calculation unit 46 assigns an identification number to each touch data having a touch threshold value or more, calculates coordinates for each of the touch input positions, and sends each identification number and coordinate information (XY) to the host system 50 send. The touch coordinate detection unit 40 may be implemented as an MCU (Micro Controller Unit).

Meanwhile, in a conventional electronic device having a touch sensor, if a user touches the touch screen (TSP), ghost noise occurs in an area outside the touch input position. Ghost noise also occurs in a single touch, but is most prominent when a user performs multi-touch (TP1 to TP5) as shown in Fig.

Ghost noises GN1 and GN2 occur in an area intersecting the touch input position or in a region adjacent to the touch input position (e.g., an adjacent Rx line). The ghost noise GN1, GN2 appears prominently when the electronic device having the touch sensor operates in the battery mode. Since the ground level of the mobile phone operating in the battery mode is in the floating state, the charging / discharging characteristics of the touch screen (TSP) are changed depending on the surrounding environment, and the ghost noise is increased.

Ghost noise (GN1, GN2) decreases the signal-to-noise ratio (SNR). In other words, the ghost noise GN1 and GN2 are factors that decrease the recognition rate of the touch. The ghost noises GN1 and GN2 vary in a component exceeding the touch threshold value T_th as shown in Fig. The ghost noises GN1 and GN2 exceeding the touch threshold value T_th can be mistaken as touch data even though they are not actual touches. The touch coordinate detecting unit 40 includes a first noise removing unit 42 and a second noise removing unit 44 for removing the ghost noise GN1 and GN2 from the touch source data.

Hereinafter, the first noise removing unit 42 and the second noise removing unit 44 for removing the ghost noise GN1 and GN2 according to the present invention will be described with reference to FIGS. 1 and 8 to 15. FIG.

FIG. 8 is a flowchart illustrating a method of controlling a touch screen according to the present invention, and FIGS. 9 to 15 are illustrations for removing ghost noise illustrated in FIG.

[TSP sensing step S110 and ADC conversion step S120]

The Tx driving circuit 32 applies a driving signal to the touch sensors Cts of the touch screen TSP. The Rx driving circuit 34 senses the voltage change of the touch sensors Cts at step S110. The Rx driving circuit 34 converts the voltage change at the touch sensors Cts into digital data, (S120)

When the user touches the touch screen TSP, the touch raw data including the ghost touch positions GT1 and GT2 together with the actual touch position TP as shown in FIG. 9 can be transmitted. The actual touch position TP appears as an actual touch RT higher than the touch threshold value T_th as shown in FIG. Sometimes ghost touch positions GT1 and GT2 also appear as ghost noises GN1 and GN2 higher than the touch threshold value T_th as shown in Fig.

Among the ghost noises GN1 and GN2, those having the peak level correspond to the impulsive noise GN1, and those having the continuously flat level correspond to the axial noise GN2. Since the method of removing the impulsive noise (GN1) and the axial noise (GN2) are different, a method of removing the impulse noise (GN1) and the axial noise (GN2) will be described separately.

[Phase Noise Removing Steps (S130 to S160): First Data Correction Method (Comp1)] [

The first noise removing unit 42 removes the axial noise GN2. The first noise remover 42 calculates the total sum and average of the entire area of the Rx lines (Rx to Rxi) in which the touch is generated when the touch primitive data is supplied. The Rx lines (Rx to Rxi) The correction threshold value C_th is set to a level that is higher than the baseline BL but lower than the touch threshold value T_th . The correction threshold value C_th is used as a filter for removing a low frequency component as a predetermined value.

The first noise remover 42 determines whether or not there is more data than the correction threshold value C_th in the touch source data (S140). If there is data larger than the correction threshold value C_th in the touch source data (Y) (RT) and ghost noise (GN1, GN2) are present. On the contrary, if there is no more data than the correction threshold value C_th in the touch source data (N), it means that there is no noise, and the subsequent noise removing steps (S150 to S190) are omitted.

The first noise removing unit 42 performs the shape search for the touch source data because there is the actual touch RT and the ghost noise GN1 and GN2 in the touch source data. A linear search method can be used.

A linear search method is a method of searching for a slope change with respect to data over a correction threshold value (C_th). The linear search method analyzes the waveform connection relation of at least three nodes with respect to the data exceeding the correction threshold C_th. According to this method, it is possible to detect slope data with a change in slope and flat data without a change in slope.

For example, since the second to fourth nodes N2 to N4 shown in FIG. 11A have different slopes, it is determined that the slope data G exists. Therefore, Fig. 11 (a) can be detected with an actual touch or impulsive noise GN1 having gradient data G1. In contrast, the second to fourth nodes N2 to N4 shown in FIG. 11B have a slope only in the second node N2, and the third and fourth nodes N3 and N4 are flat, It is determined that the data F exists. Therefore, Fig. 11 (b) can be detected with the axial noise GN2 having the flat data F. Fig.

The first noise eliminator 42 regards data having no change in slope as a noise by a linear search method and removes it as noise (S160). The impulsive noise GN1 shown in FIG. 12 has a slope Since the interval exists, it is not removed. On the other hand, the axial noise GN2 is removed because there is a flat section over a certain node. Therefore, the first noise remover 42 can remove the axial noise GN2 existing in the touch original data by the above-described method.

[Impulsive noise removing step (S170 to S190): second data correction method (Comp2)] [

The second noise removing unit 44 removes the impulsive noise GN1. The second noise eliminator 44 corrects the baseline BL upward when the touch primitive data is supplied at step S170. The second noise eliminator 44 corrects the baseline BL at a correction threshold value (C_th) or the touch threshold value (T_th). When the base line BL is upwardly corrected as described above, the level corresponding to the actual touch RT and the impulse noise GN1 below the base line BL is clipped as shown in FIG.

The second noise removing unit 44 amplifies the touch source data. (S180) The reason why the second noise removing unit 44 amplifies the touch source data is that by correcting the base line BL executed in the previous step This is because the level of the touch primitive data is lowered. The second noise removing unit 44 may amplify the touch primitive data in a manner of weighting inversely considering the rate of change of the RC according to the distance of the Tx lines (Tx to Txj). If the weights are reversely applied in this manner, the impulse noise GN1 is given a value lower than the actual touch RT.

Using this method, as shown in Fig. 14, the actual touch RT and the impulsive noise GN1 are amplified (Amp) by a given weight, and the level is increased. However, since the level of the impulse noise GN1 is lower than the level of the real touch RT, the impulse noise GN1 has a lower amplification factor than the real touch RT even if the amplification level is the same. Since the impulse noise GN1 has a level close to the level of the actual touch RT but is given a low weight, the impulsive noise GN1 has a lower amplification factor than the actual touch RT. In this case, the amplification Amp for the real touch RT and the impulsive noise GN1 may be k times (k is an integer of 1 or more) instead of once.

The second noise removing unit 44 sets the touch threshold value T_th based on the corrected baseline BL at step S190. The value T_th can be applied. The touch threshold value T_th is set to a level between 30% and 80% corresponding to the peak level between the baseline BL and the actual touch RT as shown in FIG. Therefore, the actual touch RT is recognized as a touch, whereas the impulsive noise GN1 having a lower level is recognized as a non-touch, not a touch.

On the other hand, when the level of the impulse noise GN1 is large, the second noise removing unit 44 adaptively increases the level of the touch threshold value T_th by 50% to 70% or 60% to 90% The impulsive noise GN1 may be removed. Thus, the second noise remover 44 can remove impulsive noise GN1 present in the touch primitive data in the manner described above.

On the other hand, when the impulse noise GN1 is positioned close to the real touch RT and an inflection point is formed therebetween, an error occurs in the center position algorithm for finding the center position of the real touch RT. The error of the center position algorithm leads to an error in the coordinate calculation. However, according to the present invention, it is possible to remove not only the impulsive noise GN1 but also the inflection point around the impulse noise GN1 in a manner such that the base line BL is upwardly corrected and amplified.

The ghost noise GN1 and GN2 as shown in Figs. 6 and 7 are removed or recognized as a No Touch, not a touch, so that even if a user performs a single touch or multi-touch, Can be minimized. That is, the present invention can improve the SNR by increasing the signal-to-noise ratio (SNR).

The coordinate calculation unit 46 then calculates the touch threshold value T_th in step S230. In step S230, the coordinate calculation unit 46 calculates the touch threshold value T_th, The identification number is assigned to the actual touch RT, the coordinates for the touch input position are calculated, and the identification number and the coordinate information XY are transmitted to the host system 50.

Hereinafter, a method for improving the uniformity of the touch primitive data will be described with reference to Figs. 1 and 16 to 18. Fig.

Figs. 16 to 18 are illustrations of a method for improving the uniformity of touch primitive data.

When the actual touch positions TP are uniformly distributed over the entire area of the touch screen TSP, the coordinate calculation unit 46 calculates the coordinates of the touch points TSP in accordance with Accuracy, Linearity, and Palm Rejection To improve the uniformity of the touch primitive data to improve the effect.

When the user touches one Tx line with an object of the same size as shown in Fig. 16, the drive signal (Tx Pulse) gradually decreases as shown in "TP1_P to TP5_P". In this case, as the driving signal (Tx Pulse) gradually decreases, the coordinate calculation unit 46 receives the touch raw data in the form that the actual touch gradually decreases in the order of RT1 to RT5 as shown in Fig. The reason for this phenomenon is that as the Tx line becomes longer, "? (RC time constant)" increases. 16 and 18, it is assumed that the reduction amount of the touch primitive data according to the length of the Tx line will appear linearly.

[Uniformity Improvement Steps (S211 to S212): Third Data Correction Method (Comp3)] [

In order to improve the above phenomenon, the coordinate calculation unit 46 calculates the correction coefficients Ca1 to Ca4 based on the position-dependent decrease slope G_P of the touch raw data (S211). 18 (a), the correction coefficients Ca1 to Ca4 have a larger value of Ca4 than that of Ca1 with a smaller decrease gradient G_P. When the decrease slope G_P appears linearly as shown in FIG. 18A, the correction coefficients Ca1 to Ca4 gradually increase.

The coordinate calculation unit 46 applies the correction coefficients Ca1 to Ca4 to the touch source data to average them. (S212) The coordinate calculation unit 46 adds the correction coefficients Ca1 to Ca4 to the touch source data obtained in the entire area of the touch screen TSP. (Ca1 to Ca4), the uniformity of the touch source data can be improved as shown in Fig. 18 (b).

The coordinate calculation unit 46 detects the touch input position after improving the uniformity of the raw data. (S230) The coordinate calculation unit 46 assigns an identification number to the real data RT that is equal to or larger than the touch threshold value T_th Calculates the coordinates of the touch input position, and transmits the identification number and the coordinate information (XY) to the host system 50.

Modifications of the first data correction method (Comp1) to the third data correction method (Comp3) will be described below.

19 is a modification of the first to third data correction methods.

The first data correction method (Comp1) to the third data correction method (Comp3) are methods for removing axial noise, removing impulsive noise, and improving uniformity. In the description of FIGS. 8 to 15, for example, the axial noise and the impulsive noise are removed and the uniformity is improved according to one flow in order to facilitate the understanding of the explanation.

However, the correction method according to the present invention can be performed in the order of (a), (b) and (c) of FIG. One or more of the first data correction method (Comp1) to the third data correction method (Comp3) may be omitted depending on the presence or absence of noise in the touch primitive data or the shape of the touch primitive data. For example, when only the axial noise exists in the touch primitive data, only the first data correction method (Comp1) is performed and the second data correction method (Comp2) is omitted. On the other hand, when only impulsive noise exists in the touch primitive data, only the second data correction method (Comp2) is performed and the first data correction method (Comp1) is omitted. For example, when the actual touch of the touch original data does not gradually decrease but is uniform, the third data correction method (Comp3) is omitted.

1, the touch coordinate detecting unit 40 is divided into a first noise removing unit 42, a second noise removing unit 44, and a coordinate calculating unit 46. In the embodiment of FIG. However, this is only to help understand the explanation of each configuration, and they can be algorithmically embedded in one MCU.

According to the present invention, there is provided an electronic device having a touch sensor capable of enhancing a signal-to-noise ratio (SNR) by removing mutual ghost noise and improving a touch recognition rate in a multi-touch operation, and a driving method thereof. In addition, the present invention provides an electronic device having a touch sensor capable of improving the uniformity of touch source data and improving the functions of acquiring, linearizing, and pausing the touch, and a driving method thereof.

While the present invention has been described in connection with what is presently considered to be practical exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, It will be understood that the invention may be practiced. It is therefore to be understood that the embodiments described above are to be considered in all respects only as illustrative and not restrictive. In addition, the scope of the present invention is indicated by the following claims rather than the detailed description. Also, all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

50: Host system 20: Timing controller
12: Data driving circuit 14: Scan driving circuit
DIS: LCD display panel TSP: Touch screen
30, 40: touch screen driving circuit 42: first noise removing unit
44: second noise removing unit 46: coordinate calculating unit
GN1: impulsive noise GN2: axial noise

Claims (12)

Touch sensors;
A first noise removing unit that receives touch raw data when a touch occurs in the touch sensors and detects an actual touch and an axial noise having a level equal to or higher than a correction threshold value in the touch raw data and removes the axial noise;
A second noise eliminator for detecting the actual touch and the impulsive noise having a level equal to or higher than the correction threshold value and for amplifying the actual touch and the impulsive noise to remove the impulsive noise having a lower level than the touch threshold, ; And
And a coordinate calculation unit that assigns an identification number to the touch raw data from which the axial noise and the impulsive noise are removed, and calculates coordinates for a touch input position. The method according to claim 1,
The first noise removing unit
Wherein flat data having no change in inclination over a predetermined node is discriminated as the axial noise and removed. The method according to claim 1,
The first noise removing unit
Wherein the controller is configured to analyze waveform connection relationships of three or more nodes with respect to data exceeding the correction threshold value and discriminate the tilt data having a gradient of the three or more nodes by the actual touch while the flat data having no change of the tilt is referred to as the axial noise Wherein the electronic device is a touch sensor. The method according to claim 1,
The second noise removing unit
Wherein when the actual touch and the impulsive noise are detected, the base line is upwardly corrected and the level corresponding to the actual touch and the level below the upwardly corrected base line in the impulsive noise is clipped. Electronic device. 5. The method of claim 4,
The second noise removing unit
Amplifies the actual touch and the impulsive noise, sets a touch threshold value at a level between the peak level of the up-corrected base line and the actual touch, and outputs the impulsive noise having a lower level to the touch threshold value Wherein the electronic device has a touch sensor. The method according to claim 1,
The coordinate calculation unit
When the actual touch of the touch original data obtained through one Tx line is received in a gradually decreasing manner, a correction coefficient is calculated based on the decrease slope of the touch original data by the position, and the touch original data is multiplied by the correction coefficient And averaging the currents of the plurality of touch sensors. Receiving touch raw data;
Determining whether or not there is data exceeding a correction threshold value in the touch raw data;
Detecting an actual touch and an axial noise having a level equal to or higher than the correction threshold value, and removing the axial noise;
Detecting the actual touch and impulsive noise having a level equal to or higher than the correction threshold value and amplifying the actual touch and the impulsive noise to remove the impulsive noise having a lower level than the touch threshold value; And
And adding the identification number to the touch raw data from which the axial noise and the impulsive noise have been removed, and calculating coordinates for the touch input position. 8. The method of claim 7,
The step of removing the axial noise
Wherein flatness data having no change in inclination over a predetermined node is discriminated as the axial noise and removed. 8. The method of claim 7,
The step of removing the axial noise
Wherein the controller is configured to analyze waveform connection relationships of three or more nodes with respect to data exceeding the correction threshold value and discriminate the tilt data having a gradient of the three or more nodes by the actual touch while the flat data having no change of the tilt is referred to as the axial noise And determining whether or not the touch sensor is activated. 8. The method of claim 7,
The step of removing the impulsive noise
Wherein when the actual touch and the impulsive noise are detected, the base line is upwardly corrected and the level corresponding to the actual touch and the level below the upwardly corrected base line in the impulsive noise is clipped. A method of driving an electronic device. 11. The method of claim 10,
The step of removing the impulsive noise
Amplifies the actual touch and the impulsive noise, sets a touch threshold value at a level between the peak level of the up-corrected base line and the actual touch, and outputs the impulsive noise having a lower level to the touch threshold value Wherein the touch sensor is a touch sensor. 8. The method of claim 7,
The coordinate calculation unit
When the actual touch of the touch original data obtained through one Tx line is received in a gradually decreasing manner, a correction coefficient is calculated based on the decrease slope of the touch original data by the position, and the touch original data is multiplied by the correction coefficient And averaging the currents of the plurality of touch sensors.

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