KR20110002125A - Method and apparatus for sensing touch input - Google Patents

Abstract

PURPOSE: A touch sensitive method and a device thereof are provided to exactly distinguish a multi touch with a single touch if a plurality of contact input is generated adjacently. CONSTITUTION: A contact sensing unit determines a range of sensing channel which obtained a sensing signal of critical value abnormality(S30). The contact sensing unit calculates sum of sensing signal strength obtained from the sensing channel in the range(S40). The contact sensing unit calculates rate between the sum of the sending signal strength obtained from a center sensing channel in the range(S60). The contact detector determines contact input by comparing between predetermined reference value and rate(S70~S90).

Description

Touch sensing method and device {METHOD AND APPARATUS FOR SENSING TOUCH INPUT}

The present invention relates to a touch sensing method and apparatus, and discloses a touch sensing method and apparatus capable of accurately distinguishing a multi-touch and a single touch.

The touch sensing device can be classified into a resistive film type, a capacitive type, an ultrasonic type, and an infrared type according to an operation method. Among the capacitive type, the touch sensing panel has a thin thickness, high durability, and multi-touch. Has the inherent advantage.

1 is a plan view showing an electrode structure of a conventional capacitive touch sensing device. Referring to FIG. 1, the touch sensing panel 10 includes a plurality of X electrodes 11 extending in the Y-axis direction and connected to the X1-X8 sensing channels, respectively, and extending in the X-axis direction and respectively in the Y1-Y8 sensing channels. A plurality of Y electrodes 12 are connected.

When contact inputs are simultaneously applied to points 1 and 2 of FIG. 1 (multi-touch), a sensing signal having a relatively higher intensity than that of other sensing channels may be obtained from the sensing channels X3, X6, Y3, and Y5. Meanwhile, when a touch input is applied to point 1 of FIG. 1 (single touch), a sensing signal having a strong intensity may be detected from the sensing channels X3 and Y3. As described above, since the detection signal distribution for each sensing channel is different depending on whether the contact input is a multi-touch or a single touch, the multi-touch can be distinguished using this.

In general, a method using a maximum value and a minimum value of a detection signal distribution is used to distinguish a multi-touch and a single touch. When contact inputs are simultaneously applied to the first and second points of FIG. 1, the maximum value of the sensing signal appears in the sensing channels X3 and X6 in the X direction, and the minimum value appears in the vicinity of X4 and X5. In the Y direction, the maximum value of the detection signal is displayed in the sensing channels Y3 and Y5, and the minimum value is displayed in the vicinity of Y4. Accordingly, the multi-touch may be determined using a plurality of maximum values and whether a minimum value is detected among the plurality of maximum values in the detection signal distribution.

However, such a determination method has a problem that it is difficult to distinguish a multi-touch applied from a single touch. When contact inputs occur simultaneously at points 3 and 4 of FIG. 1, the maximum value of the detection signal appears in X6 in the X direction, and the maximum value of the detection signal in Y2 in the Y direction. That is, since a plurality of maximum values are not detected and a minimum value is not detected among the maximum values, a touch input simultaneously generated at points 3 and 4 may be erroneously determined as a single touch.

Accordingly, an object of the present invention is to provide a touch sensing method and apparatus capable of accurately distinguishing a multi-touch from a single touch.

In order to achieve the above object, a touch sensing method according to the present invention includes: acquiring a sensing signal generated by a touch input for each sensing channel, determining a range of a sensing channel for acquiring a sensing signal having a threshold value or more, Calculating a sum of sensing signal strengths obtained from an included sensing channel, calculating a ratio between sensing signal strengths obtained from a central sensing channel within the range and the sum, and comparing the ratio with a predetermined reference value And determining whether the contact input is multi-touch.

Meanwhile, the touch sensing apparatus according to the present invention may obtain a sensing signal generated by the sensing electrode by a sensing channel for each sensing channel by a substrate, a sensing electrode disposed to extend in a first axial direction on the substrate, and the touch. And a touch sensing unit to determine an input, wherein the touch sensing unit determines a range of a sensing channel that acquires a sensing signal of a first threshold or more, and includes a sum of sensing signal intensities obtained from sensing channels included in the range and the range. It is determined whether the touch input is multi-touch based on the ratio of the sensed signal strength obtained from the central sensing channel.

According to the present invention, in determining the multi-touch applied to the touch sensing panel, a ratio between the sum of the sensing signal strengths included in the predetermined range of the sensing signal distribution and the sensing signal strength of the central sensing channel of the corresponding range is used. Therefore, even when a plurality of contact inputs are generated adjacent to each other, the multi-touch can be recognized accurately by distinguishing from the single touch.

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings.

2 is a flowchart provided to explain a touch sensing method according to an embodiment of the present invention. Referring to FIG. 2, in the touch sensing method according to the present embodiment, the touch sensing unit detects a sensing signal from a sensing electrode (S10). The sensing electrode is disposed in a specific pattern on the touch sensing panel and is electrically connected to the touch sensing unit through a wiring pattern. The sensing signal is a signal according to a change in electrical characteristics generated by the touch input. In one embodiment, the touch sensing unit may detect a change in capacitance generated at the sensing electrode by the touch input as a sensing signal.

When the sensing signal is detected, the touch sensing unit determines whether there is a sensing channel in which a sensing signal of a threshold value or more is detected (S20). Since a signal can be detected even when a touch input is not applied due to noise introduced into the touch sensing device from the outside, a signal below a predetermined threshold is preferably treated as noise rather than a sensing signal. As a result of the determination in step S20, if there is no sensing channel in which a detection signal of a threshold value or more is detected, the touch sensing unit determines that a touch input is not applied.

As a result of the determination in step S20, if there is a sensing channel in which a sensing signal of a threshold or more is detected, the touch sensing unit calculates a range of sensing channels in which a sensing signal of a threshold or more is detected (S30). The touch sensing unit may independently sense each sensing channel to obtain a sensing signal from the sensing electrode. Hereinafter, throughout the present specification, the range of a sensing channel in which a sensing signal of a threshold or more is detected is a sensing in which a sensing signal of a threshold or more is first detected when the sensing signal of a threshold or more is detected based on one of horizontal or vertical directions on a sensing area of the touch sensing apparatus. It means the range from the channel to the sensing channel where the sensing signal above the threshold is finally detected.

For example, suppose that eight electrodes are disposed in the vertical direction and connected to the sensing channels X1 to X8, respectively, and eight electrodes are disposed in the horizontal direction and connected to the sensing channels Y1 to Y8. At this time, if a detection signal above the threshold is detected in X2, X3, X6, X7 by the touch input, and a detection signal smaller than the threshold is detected in X1, X4, X5, X8, the touch detection unit may detect X2 to X7 above the threshold. The sensing signal is determined as the range of the detected sensing channel. In the same manner as described above, a range of the sensing channels in which a sensing signal of a threshold value or more is detected for the sensing channels Y1 to Y8 may be calculated.

The touch sensing unit calculates the sum of the sensing signal strengths within the sensing channel range calculated in step S30 (S40). According to the above example, the sum is calculated by adding together the sensing signal strengths acquired in the sensing channels X2, X3, X4, X5, X6, and X7. At this time, a sensing signal below a threshold detected in sensing channels X4 and X5 is also added to the sum.

When the sum of the sensing signal strengths is calculated, the touch sensing unit calculates the strength of the sensing signal corresponding to the center sensing channel among the sensing channels included in the sensing channel range calculated in step S30 (S50). For example, assuming that the range of the sensing channel calculated in step S30 is X2 to X6, the strength of the sensing signal detected in the center channel X4 may be simply determined as the strength of the sensing signal corresponding to the central sensing channel.

On the other hand, assuming that the sensing channel range calculated in step S30 is X2 to X7, the central sensing channel cannot be specified as one sensing channel. In this case, the sensing signal strength obtained from the sensing channel adjacent to the average of the index value of the boundary sensing channel for determining the range is used. That is, since the index values of the boundary sensing channels are 2 and 7, the average of the sensing signal strengths acquired at X4 and X5 adjacent to the average of the index values 4.5 may be applied as the strength of the sensing signal corresponding to the central sensing channel.

The touch sensing unit calculates a ratio between the sum of the sensing signal strengths calculated in step S40 and the sensing signal strengths corresponding to the central sensing channel calculated in step S50 (S60), and compares the ratio with a predetermined reference value (S70). . As a result of the comparison, if the ratio is greater than the reference value, the touch input is determined as a single touch (S90). If the ratio is less than the reference value, the touch input is determined as the multi-touch (S80).

3 is a plan view illustrating a touch sensing apparatus to which a touch sensing method according to an embodiment of the present invention is applied. Referring to FIG. 3, the touch sensing apparatus 300 according to the present exemplary embodiment includes a substrate 310 and sensing electrodes 320 and 330 disposed on the substrate 310. It is assumed that the sensing electrodes 320 and 330 are a one-layer touch sensing device 300 disposed only on one surface of the substrate 310, and the sensing electrodes 320 and 330 are arranged on left and right sides of the substrate 310. It is connected to the sensing channels L1 to L8 and R1 to R8 of the touch sensing unit (not shown) through a pattern (not shown).

Each of the sensing electrodes 320 and 330 is formed in a sawtooth shape including a plurality of protrusions and indents, and the protrusions and the indents of the sensing electrodes 320 and 330 facing each other are disposed at the same position in the vertical direction to be engaged with each other. do. Using the above structure, the sensing electrodes 320 and 330 may be formed only on one surface of the substrate 310, and the two-dimensional position of the contact input may be accurately determined.

In this embodiment, the contact areas A and B are formed at the same time by the multi-touch in which a plurality of contact inputs are simultaneously applied. The contact region formed by the contact overlaps at least some of the sensing electrodes 320 and 330, and a capacitance change occurs in proportion to the overlapped area between the sensing electrodes 320 and 330 and the contact region. The touch detector detects a change in capacitance generated by the sensing electrodes 320 and 330 through each sensing channel as a sensing signal. The contact region A detects a detection signal from the sensing electrodes 320 and 330 connected to the sensing channels L2, R2, L3, and R3, and the contact region B is connected to the sensing channels L5, R5, L6, and R6. The sensing signal may be detected from the sensing electrodes 320 and 330.

4 is a graph illustrating a distribution of sensing signals generated by the touch sensing apparatus illustrated in FIG. 3. Referring to FIG. 4, as described above, a strong detection signal may be detected in the sensing channels L2, R2, L3, R3, L5, R5, L6, and R6. The threshold value shown in the graph is a value for distinguishing the detection signal generated by the sensing electrodes 320 and 330 by the touch input and the noise signal due to noise from the outside, physical deformation of the touch sensing panel, moisture, etc. It may be set to an appropriate value according to the use environment of the touch sensing device.

The touch sensing unit periodically detects a sensing signal from the sensing electrode, and when a sensing signal having a strength greater than or equal to a threshold is detected, it may be determined that a touch input has occurred. When the contact inputs A and B are applied to obtain a detection signal distribution as shown in FIG. 4, the contact detection unit senses a detection channel in which a detection signal above a threshold is detected from a minimum value and a minimum value among the index values of the sensing channel where a detection signal above a threshold is detected. Determine the range of. In the present embodiment, the sensing signal strength for each sensing channel is compared with a threshold to determine the sensing channels L2 and R2 to the sensing channels L6 and R6 within the above ranges.

When the range is determined, the touch sensing unit determines the center sensing channel among the sensing channels included in the range. In a first embodiment, the central sensing channel may be determined as a sensing channel corresponding to an arithmetic mean of the indices of the boundary sensing channel defining the range. In the present embodiment, since the indexes of the boundary sensing channels for determining the range are 2 and 6, respectively, sensing channels L4 and R4 having index values corresponding to 4, which is an arithmetic mean of the index values of the boundary sensing channels, are regarded as the central sensing channels. Can be.

According to the second embodiment of the present invention, the touch sensing unit may determine the central sensing channel by using a weighted average of sensing signals for each sensing channel included in the range. Referring to FIG. 4, coordinates of the midpoint of the range are obtained by using the weighted average of the sensing signals acquired for each sensing channel in the range defined from the sensing channels L2 and R2 to the sensing channels L6 and R6. The coordinate of the center can be calculated by Equation 1.

와

는 각각 감지 전극(320, 330)의 가로, 세로 길이를 의미한다. 즉, 도 3에서는 감지 전극(320, 330)이 서로 맞물려 형성하는 직사각형 형태의 전극 쌍 하나의 너비가

이며, 전극 쌍 하나의 높이가

에 해당한다.In Equation 1, L (n) and R (n) represent the strengths of the sensing signals obtained from the sensing channels Ln and Rn, respectively.

Wow

Denotes the horizontal and vertical lengths of the sensing electrodes 320 and 330, respectively. That is, in FIG. 3, the width of one pair of rectangular electrodes formed by engaging the sensing electrodes 320 and 330 with each other is

The height of one electrode pair

Corresponds to

When the weighted average is calculated from the detection signal distribution shown in FIG. 4 by Equation 1, the coordinates of the midpoint of the sensing channel range defined by L6 and R6 can be obtained from L2 and R2. In this embodiment, since the sum of the sensing signal strengths from L2 to R3 is slightly larger than the sum of the sensing signal strengths from L5 to R6, the coordinates of the midpoint are also slightly from the exact midpoints of the contact areas A and B toward the contact area A ( To the top left). The touch detector may determine the sensing channel adjacent to the coordinate of the midpoint as the central sensing channel.

In the present embodiment, since it is assumed that the multi-touch occurs by the contact areas A and B, the center sensing in the first embodiment using the arithmetic mean of the boundary sensing channel index and the second embodiment using the weighted average of the sensed signals The difference in channels does not appear much. In particular, in the calculation process, since the first embodiment is simpler than the second embodiment, it is efficient to apply the first embodiment in the general case. However, in order to prevent multi-touch misrecognition due to a touch input unintentional by the user or an external environmental factor, it is preferable to apply the second embodiment. This will be described later.

When determining the center sensing channel, the touch sensing unit calculates a ratio between the sum of the sensing signal strengths of all sensing channels included in the sensing range L2 to R6 and the sensing signal strength obtained from the central sensing channel. The detection signal distribution shown in FIG. 4 may be calculated as in Equation 2.

The touch sensing unit compares the ratio calculated according to Equation 2 with a predetermined reference value, and determines that the touch input is multi-touch when the ratio is less than (or less than) the reference value. When a multi-touch occurs, a plurality of contact regions are formed, and a sensing channel in which a sensing signal is relatively detected between the plurality of contact regions appears. Therefore, according to the formula shown in Equation 2, the multi-touch and the single touch may be distinguished by using a ratio between the sensing signal strengths of the sensing channels within a predetermined range and the sensing signal strength of the central sensing channel within the predetermined range. .

5 is a plan view illustrating a touch sensing apparatus to which a touch sensing method according to an embodiment of the present invention is applied. Referring to FIG. 5, in the touch sensing apparatus according to the present exemplary embodiment, sensing electrodes 520 and 530 extending in different directions are disposed on the substrate 510. Hereinafter, for convenience of description, an electrode extending in the Y-axis direction and connected to the sensing channels X1 to X8 is referred to as a first sensing electrode 520, and an electrode extending in the X-axis direction and connected to the sensing channels Y1 to Y8 is described. It is referred to as a two sensing electrode 530. In the present exemplary embodiment, the first sensing electrode 520 and the second sensing electrode 530 may be disposed on different layers of the substrate 510, or may be formed on separate substrates 510 and electrically separated from each other.

Referring to FIG. 5, two contact inputs having substantially the same coordinates on the X axis and separated by the Y axis coordinates are simultaneously applied. Contact regions C and D are formed by contact inputs, respectively, and the contact regions C include a first sensing electrode 520 connected to sensing channels X6 and X7, and a second sensing electrode 530 connected to sensing channels Y2 and Y3. The contact area D overlaps the first sensing electrode 520 connected to the sensing channels X6 and X7 and the second sensing electrode 530 connected to the sensing channels Y6 and Y7.

FIG. 6 is a graph illustrating a distribution of sensing signals generated by the touch sensing apparatus illustrated in FIG. 5. Referring to FIG. 6, sensing signals are generated in the sensing channels X1 to X8 and Y1 to Y8 by the contact regions C and D, respectively. As in the graph shown in FIG. 4, a constant sensing signal may be detected even in a sensing channel that does not directly overlap the contact regions C and D. The touch sensing unit processes the sensing signal below a threshold as a noise to determine the accuracy of the touch position determination. Can increase.

The first graph of FIG. 6 shows the intensity distribution of the sensing signal detected by the touch sensing unit from the sensing channels X1 to X8. Since the first sensing electrode 520 connected to the sensing channels X6 and X7 overlaps the contact regions C and D, a relatively very strong sensing signal is detected from the sensing channels X6 and X7.

The second graph of FIG. 6 shows the intensity distribution of the detection signal detected by the touch sensing unit from the sensing channels Y1 to Y8. Since the second sensing electrode 530 connected to the sensing channels Y2 and Y3 overlaps the contact area C, and the second sensing electrode 530 connected to the sensing channels Y6 and Y7 overlaps the contact area D, the sensing channel Y2, A relatively strong sense signal is detected from Y3, Y6, and Y7.

The process described in FIG. 4 is applied to this embodiment as it is. However, when the touch sensing method according to the present invention is applied to the first graph of FIG. 6, the range of the sensing channel for acquiring the sensing signal above the threshold is limited to X6 to X7, and the center sensing channel cannot be determined. The displayed touch input can be mistaken for a single touch.

Therefore, in the two-layer touch sensing apparatus as shown in FIG. 5, it is preferable to apply the touch sensing method according to the present invention to both the X and Y sensing channels. Therefore, even if the touch input cannot be determined as multi-touch in the sensing signals acquired from the sensing channels X1 to X8, the touch input illustrated in FIG. 5 may be determined as the multi-touch from the sensing signal distribution obtained from the sensing channels Y1 to Y8. .

In the second graph of FIG. 6, the sensing channel range obtained from the sensing signal above the threshold is determined as Y2 to Y7. The central sensing channel is determined as the sensing channels Y4 and Y5 by applying the arithmetic mean of the index values of the boundary sensing channels in the range, and the touch sensing unit is the sum of the sensing signal strengths obtained from the sensing channels Y2 to Y7 and the sensing channels Y4, Calculate the ratio between the average of the sensed signal strengths obtained from Y5. The ratio is compared with a predetermined reference value to determine whether the multi-touch.

7 is a view provided to explain a method of distinguishing a multi-touch from a single touch by applying a touch sensing method according to an embodiment of the present invention. Referring to FIG. 7, detection signals of more than a threshold value are detected from the sensing channels X2 to X5 and X7 by the touch input assumed in the present embodiment.

In the detection signal distribution shown in FIG. 7, the range of the sensing channel through which the detection signal above the threshold value is detected is defined as X2 to X7. In calculating the ratio for determining the multi-touch, if the center sensing channel is defined simply by the arithmetic mean of the boundary sensing channel index, the ratio may be calculated as shown in Equation (3).

X (n) represents the strength of the sensing signal acquired in the sensing channel Xn. On the other hand, if the coordinates are calculated by the weighted average within the range of the sensing channel in which a detection signal of a threshold value or more is detected, and the sensing channel adjacent to the calculated coordinates is defined as the central sensing channel, the ratio may be calculated as in Equation 4. .

In Equation 4, the index _center is an index value of the center sensing channel, and is defined as a coordinate calculated by a weighted average of sensing signals of each channel within a sensing channel range in which a sensing signal of a threshold or more is detected. In this case, since the right side of the second formula of Equation 4 is generally calculated as a non-integer value, the index _center may be determined as the nearest integer to the coordinate calculated by the weighted average.

If the index values of the central sensing channel (index _center) is determined, the touch sensing unit calculates the detected signal intensity X _(center index) corresponding to the central sensing channels. When the index _center is determined as one integer by the second formula of Equation 4, the sensing signal strength obtained from the sensing channel having an index corresponding to the determined integer may be applied as X (index _center ). Alternatively, two integers adjacent to the value calculated from the right side of the second formula of Equation 4 are determined, and the sensing signal strengths obtained from two sensing channels having respective indices corresponding to the determined integers are represented by X (index _center). You can also apply

Applying the method to FIG. 7, the index _center is defined as a real number greater than 3 and less than 4. Therefore, X (index _center ) may apply the intensity of the sensing signal acquired from the sensing channel X3 or the average of the sensing signal strength obtained from the sensing channels X3 and X4, respectively.

On the other hand, according to Equation 3, the strength of the sensing signal corresponding to the center sensing channel is determined by the arithmetic mean of the sensing signal strengths acquired in the sensing channels X4 and X5. Therefore, in Equation 3, the value of the ratio Ratio required for the multi-touch determination is smaller than in Equation 4. Since the touch sensing unit determines that the ratio value is smaller than the predetermined reference value, the touch detection unit may determine the multi-touch as shown in FIG. 7 when the equation 3 is applied, compared to the case where the equation 4 is applied.

The sensing signal distribution as shown in the graph shown in FIG. 7 is characterized in that the actual contact area overlaps the sensing electrodes connected to the sensing channels X2 to X5, and is sensed in the sensing channel X7 due to external noise or proximity of the conductive object rather than the actual contact. The detection signal above the threshold may be detected. At this time, if it is determined that the touch input is multi-touch, a command or an application different from the one intended by the user may be executed. Therefore, as shown in Equation 4, the center sensing channel may be determined using a weighted average of the sensing signals for each channel within the sensing channel range in which the sensing signal having the threshold value or more is acquired, thereby increasing the accuracy of the multi-touch recognition.

While the preferred embodiments of the present invention have been shown and described, the present invention is not limited to the specific embodiments described above, and the present invention is not limited to the specific embodiments of the present invention, without departing from the spirit of the invention as claimed in the claims. Many modifications are possible to those skilled in the art. In addition, matters that can be easily inferred from the accompanying drawings are to be regarded as included in the contents of the present invention even if they are not described in the detailed description, and various modifications may be separately understood from the technical spirit or the prospect of the present invention. I will not.

1 is a view provided to explain a general touch sensing method;

2 is a flowchart provided to explain a touch sensing method according to an embodiment of the present invention;

3 is a plan view illustrating a touch sensing apparatus to which a touch sensing method is applied according to an embodiment of the present invention;

4 is a graph illustrating a distribution of sensing signals generated by the touch sensing apparatus illustrated in FIG. 3;

5 is a plan view illustrating a touch sensing apparatus to which a touch sensing method is applied according to an embodiment of the present invention;

FIG. 6 is a graph illustrating a distribution of sensing signals generated by the touch sensing apparatus illustrated in FIG. 5;

7 is a view provided to explain a method of distinguishing a multi-touch from a single touch by applying a touch sensing method according to an embodiment of the present invention.

Claims (13)

Acquiring a sensing signal generated by a touch input for each sensing channel; Determining a range of a sensing channel for acquiring a sensing signal above a threshold; Calculating a sum of sensing signal strengths obtained from sensing channels included in the range; Calculating a ratio between the sensed signal strength obtained from a central sensing channel within the range and the sum; And Comparing the ratio with a predetermined reference value to determine whether the touch input is multi-touch; Touch detection method comprising a. The method of claim 1, wherein the determining step, And a sensing channel range from the first sensing channel to the last sensing channel to the last sensing channel in the sensing signal distribution indicating the intensity of each sensing channel of the sensing signal. The method of claim 2, wherein the determining step, And determining whether the touch input is multi-touch with reference to the sensing channel range. The method of claim 1, And a sensing signal obtained from the central sensing channel is an average of sensing signal strengths obtained from sensing channels adjacent to the center of the range. The method of claim 1, wherein the determining step, If the ratio is less than or equal to the reference value, determining the touch input as multi-touch. The method of claim 1, The reference value is a touch sensing method, characterized in that the variable determined according to the range of the sensing channel. The method of claim 1, And a center sensing channel within the range is determined using a weighted average of the sensing signals for each sensing channel included in the range. Board; A sensing electrode disposed to extend in a first axial direction on the substrate; And A touch sensing unit configured to determine the touch input by acquiring a sensing signal generated by the sensing electrode for each sensing channel by a touch input; Including, The touch sensing unit may determine a range of a sensing channel that acquires a sensing signal of a first threshold or more, and may determine the sum of the sensing signal strengths obtained from the sensing channels included in the range and the sensing signal strengths obtained from the central sensing channel within the range. And determining whether the touch input is multi-touch based on a ratio. The method of claim 8, wherein the touch sensing unit, And determining whether to multi-touch in a second axis direction crossing the first axis based on the ratio. The method of claim 8, A second sensing electrode extending in a second axis direction crossing the first axis; More, The touch sensing unit may determine whether to multi-touch in the first axis direction based on a second sensing signal obtained from the second sensing electrode. The method of claim 8, wherein the touch sensing unit, And determining the touch input as multi-touch if the ratio is equal to or less than a predetermined reference value determined according to the range. The method of claim 8, wherein the touch sensing unit, And determining the central sensing channel by using a weighted average of sensing signals for each sensing channel included in the range. The method of claim 8, wherein the touch sensing unit, And a plurality of central sensing channels, determining whether the touch input is multi-touch based on an average of sensing signal strengths obtained from each of the central sensing channels and a ratio of the sum.

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