Method For Driving Touch Panel

Abstract

A method for driving a touch panel including driving lines, sensing lines, and node capacitors between neighboring and/or overlapping driving lines and sensing lines is disclosed. The method includes selecting two or more of the driving lines, and simultaneously driving the selected driving lines with driving signals. Each driving signal has three or more voltages of different levels.

Description

[0001] This application claims the benefit of the Korean Patent Application No. 10-2013-0022088, filed on Feb. 28, 2013, which is hereby incorporated by reference as if fully set forth herein.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] Embodiments of the present disclosure relate to a method for driving a touch panel.

[0004] 2. Discussion of the Related Art

[0005] Generally, measurement of the capacitance of each sensing node in a touch panel is achieved by applying a pulse sequence at a specific frequency through a driving line by a driving unit, and measuring a signal received through a sensing line by a sensing unit.

[0006] In this case, the frequency of the pulse sequence may be influenced by various environmental noise such as charger noise and fluorescent lamp noise. To this end, methods for suppressing influence of such environmental noise may be applied. In addition, an appropriate signal processing scheme may be applied to the sensing unit in order to extract a signal component corresponding to the measured capacitance.

SUMMARY OF THE INVENTION

[0007] Embodiments of the present disclosure provide a method for driving a touch panel capable of reducing a harmonic component included in a driving signal, and achieving an enhancement in sensitivity and jitter immunity.

[0008] Additional advantages, objects, and features of the embodiments will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned from practice of the embodiments. The objectives and other advantages of the embodiments may be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

[0009] To achieve these objects and other advantages and in accordance with the purpose of the embodiments, as embodied and broadly described herein, a method for driving a touch panel including driving lines, sensing lines, and node capacitors formed between neighboring or overlapping ones of the driving lines and the sensing lines includes selecting two or more of the driving lines, and simultaneously driving the selected driving lines by driving signals, wherein each of the driving signals has three or more voltages of different levels.

[0010] Each driving signal may be a periodic signal, and may have three or more voltages of different levels in every period thereof.

[0011] Each driving signal may include a first signal portion or time period having a first voltage level, a second signal portion or time period having a second voltage level, and a third signal portion or time period having a third voltage level. The first voltage level, the second voltage level, and the third voltage level may be different.

[0012] The first voltage level may be higher than the second voltage level. The second voltage level may be higher than the third voltage level.

[0013] The first voltage level may be a positive (+) voltage. The second voltage level may be 0 or a ground potential, and the third voltage level may be a negative (-) voltage.

[0014] The first signal portion or time period and the third signal portion or time period may alternate. The second signal portion or time period may be between the first signal portion or time period and the third signal portion or time period.

[0015] Each driving signal may have a duty ratio second within a range of more than 0.25, but less than 1. The duty ratio of each driving signal may be a ratio or percentage of a sum of a length of the first signal portion or time period and a length of the third signal portion or time period in each period of the driving signal.

[0016] The different portions of the driving signal may have the same phase.

[0017] The driving signal applied to at least one of the selected driving lines may have a phase different from other driving signals applied to other (e.g., the remaining) driving lines.

[0018] The first signal portion or time period and the third signal portion or time period of each driving signal may have equal lengths within one period of the driving signal.

[0019] The second signal portion or time period may be before the first signal portion or time period and/or after the third signal portion or time period.

[0020] In another aspect, a method for driving a touch panel including driving lines, sensing lines, and node capacitors between overlapping ones of the driving lines and the sensing lines includes selecting two or more of the driving lines, and simultaneously driving the selected driving lines by driving signals, wherein each driving signal is a periodic signal and has a period comprising a first portion or time period in which the driving signal has a first voltage level, a second portion or time period in which the driving signal has a second voltage level lower than the first voltage level, and a third portion or time period in which the driving signal has a third voltage level lower than the second voltage level.

[0021] Each driving signal may have a duty ratio within a range of more than 0.25, but less than 1. The duty ratio of each driving signal may be a ratio or percentage of a sum of a length of the first portion or time period and a length of the third portion or time period in each period of the driving signal.

[0022] The second portion or time period of the driving signal may be present between the first portion or time period and the third portion or time period.

[0023] The first portion or time period and the third portion or time period may be equal.

[0024] The length of the second portion or time period may be shorter than the first portion or time period and/or the third portion or time period.

[0025] The different portions or time periods of an individual driving signal may have the same phase.

[0026] The driving signal applied to at least one of the selected driving lines may have a phase different from other driving signals applied to other (e.g., the remaining) driving lines.

[0027] In another aspect, a method for driving a touch panel including driving lines, sensing lines, and node capacitors between overlapping ones of the driving lines and the sensing lines includes selecting two or more of the driving lines, simultaneously driving the selected driving lines by driving signals having two or more voltages of different levels, and receiving an overlapped or combined signal from the simultaneously-driven driving signals, wherein the overlapped or combined signal is a periodic signal having three or more voltages of different levels.

[0028] The overlapped or combined signal may have a period comprising, in sequence, a first portion or time period in which the overlapped or combined signal has a first voltage level, a second portion or time period in which the overlapped or combined signal has a second voltage level lower than the first voltage level, a third portion or time period in which the overlapped or combined signal has a third voltage level lower than the second voltage level, and a fourth portion or time period in which the overlapped or combined signal has the second voltage level.

[0029] Embodiments of the present disclosure may reduce a harmonic component included in a driving signal while achieving an enhancement in sensitivity and jitter immunity.

[0030] It is to be understood that both the foregoing general description and the following detailed description of the embodiments are exemplary and explanatory and are intended to provide further explanation of the embodiments as claimed.

BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Arrangements and embodiments may be described in detail with reference to the following drawings. In the drawings:

[0032] FIG. 1 is a diagram illustrating an exemplary configuration of a touchscreen device according to one or more embodiments of the present disclosure;

[0033] FIG. 2 is a waveform diagram illustrating an example of a driving signal applied to two or more driving lines illustrated in FIG. 1;

[0034] FIG. 3 is a circuit diagram illustrating an embodiment of a sensing circuit included in the sensing unit illustrated in FIG. 1;

[0035] FIG. 4 is a waveform and/or diagram illustrating examples of a driving signal having two voltages of different levels and a driving signal having three voltages of different levels in accordance with one or more embodiments of the present disclosure;

[0036] FIG. 5 is a waveform illustrating results of a simulation showing a harmonic component of the driving signal illustrated in FIG. 4 as having two voltages of different levels;

[0037] FIG. 6 is a waveform illustrating results of a simulation showing a harmonic component of the driving signal according to the embodiment(s) of FIG. 4;

[0038] FIG. 7 is a waveform diagram illustrating a signal received by the sensing unit from each sensing line when driving signals having the same phase are simultaneously applied to two or more driving lines corresponding to the sensing line, respectively;

[0039] FIG. 8 is a waveform diagram illustrating an example in which at least one driving signal simultaneously applied to driving lines has a phase different from those of the remaining driving signals;

[0040] FIG. 9 is a method for simultaneously driving two driving lines in accordance with one or more embodiments of the present disclosure;

[0041] FIGS. 10A to 10C are waveform diagrams illustrating examples of two exemplary driving signals illustrated in FIG. 9; and

[0042] FIG. 11 is a waveform diagram illustrating a method for simultaneously driving two driving lines in accordance with one or more additional embodiments.

DETAILED DESCRIPTION OF THE INVENTION

[0043] In the following description of various embodiments, it will be understood that, when an element such as a layer (film), region, pattern, or structure is referred to as being "on" or "under" another element, it can be directly on or under the other element, or it can be indirectly on or under the other element with one or more intervening elements present. In addition, terms such as "on" or "under" should be understood on the basis of the drawings.

[0044] In the drawings, dimensions of layers may be exaggerated, omitted or schematically illustrated for clarity and convenience of description. In addition, dimensions of constituent elements do not entirely or necessarily reflect actual dimensions thereof. The same reference numerals denote the same constituent elements, respectively. Hereinafter, a method for driving lines of a touch panel in accordance with one or more embodiments and a touchscreen device according to one or more embodiments will be described with reference to the accompanying drawings.

[0045] FIG. 1 is a diagram illustrating a configuration of a touchscreen device 100 according to one or more embodiments of the present disclosure.

[0046] Referring to FIG. 1, the touchscreen device 100 includes a touch panel 10, a driving unit 20, a sensing unit 30, and a control unit 40.

[0047] The touch panel 10 provides a plurality of sensing nodes P11 to Pnm (n and m being natural numbers greater than 1) having substantially independent functions, but different positions.

[0048] The sensing nodes P11 to Pnm may be described as coordinates, sensing points, nodes, or a sensing node array.

[0049] For example, the touch panel 10 may include a plurality of driving lines X1 to Xn (n being a natural number greater than 1), a plurality of sensing lines Y1 to Ym (m being a natural number greater than 1), and node capacitors C11 to Cnm (n and m being natural numbers greater than 1) formed between overlapping driving lines X1 to Xn and sensing lines Y1 to Ym.

[0050] The driving lines X1 to Xn may be described as driving signal lines or driving electrodes.

[0051] The sensing lines Y1 to Ym may be described as sensing signal lines or sensing electrodes.

[0052] Although the driving lines and sensing lines are illustrated in FIG. 1 as intersecting each other, embodiments of the present disclosure are not limited to such an arrangement. The driving lines and sensing lines may be embodied such that they do not intersect each other.

[0053] Each sensing node (for example, the sensing node P11) may be defined by the first node capacitor (for example, C11) between the first driving line (for example, X1) and the first sensing line (for example, Y1).

[0054] For example, each driving line Xi (i being a natural number satisfying 0<i.ltoreq.n) and each sensing line Yj (j being a natural number satisfying 0<j.ltoreq.m) may be isolated from each other through insulation, and one node capacitor Cij may be formed between the driving line Xi and the sensing line Yj.

[0055] For example, the touch panel 10 may include an electrode pattern layer (not shown) including sensing electrodes and driving electrodes spaced apart from each other, a substrate (not shown) at a front side of the electrode pattern layer, and an insulating layer (not shown) at a back side of the electrode pattern layer. The electrode pattern layer may have various layouts in accordance with a designing method applied thereto.

[0056] The electrode pattern layer may include least one transparent conductive material, for example, indium tin oxide (ITO), tin oxide (TO), indium zinc oxide (IZO), indium tin zinc oxide (ITZO), indium aluminum zinc oxide (IAZO), indium gallium zinc oxide (IGZO), indium gallium tin oxide (IGTO), aluminum zinc oxide (AZO), antimony tin oxide (ATO), gallium zinc oxide (GZO), carbon nanotubes, a conductive polymer, silver, and transparent copper ink.

[0057] The electrode pattern layer may be on or over one or more layers of glass or plastic, to form a sensing node array including sensing nodes P11 to Pnm (n and m being natural numbers greater than 1).

[0058] The substrate may comprise or have the form of a dielectric film exhibiting high light transmissivity. For example, the substrate may include at least one of glass, polyethylene terephthalate (PET), polyethylene naphthalate (PEN), a polyimide (PI), or a (meth)acrylate polymer.

[0059] The insulating layer may be a transparent insulating layer including, for example, PET. In another embodiment, a shield layer (not shown) may be beneath the insulating layer in order to eliminate electromagnetic interference (EMI) and noise entering the electrode pattern layer.

[0060] The touch panel 10 may be merged with a layer for display or may share a driving or sensing path with the layer in accordance with an appropriate panel designing method.

[0061] When the touch panel 10 is not coupled with a display, a two-dimensional sensing node array may be configured in accordance with an appropriate method. Embodiments are also applicable to a touch sensing system comprising or constituted by a two-dimensional sensing node array.

[0062] The driving unit 20 is electrically connected with a plurality of driving lines X1 to Xn (n being a natural number greater than 1), to supply a driving signal to one or more of the driving lines X1 to Xn.

[0063] For example, the driving unit 20 may simultaneously supply a driving signal to two or more of the driving lines X1 to Xn.

[0064] Here, "simultaneously" may include not only events occurring nearly simultaneously, but also events occurring precisely simultaneously. For example, events occurring simultaneously may mean events that nearly simultaneously start, and nearly simultaneously end, and/or events having periods that at least partially overlap.

[0065] The driving signal applied to two or more driving lines may have three or more voltages of different levels, and may be a periodic signal.

[0066] For example, the driving signal applied to two or more driving lines may have three voltages of different levels within each period.

[0067] FIG. 2 illustrates an example of a driving signal Vd applied to two or more of the driving lines illustrated in FIG. 1.

[0068] Referring to FIG. 2, the driving signal Vd may have a first voltage level, +Vp, a second voltage level, Vss, and a third voltage level, -Vn. The first voltage level V+p, second voltage level Vss, and third voltage level -Vn may have different values, respectively.

[0069] For example, the driving signal Vd may include a first signal portion or time period V1 having a first voltage level +Vp, a second signal portion or time period V2 having a second voltage level Vss, and a third signal portion or time period V3 having a third voltage level -Vn. In this case, the first voltage level V+p, second voltage level Vss, and third voltage level -Vn may have different values, respectively.

[0070] The first voltage level +Vp may be higher than the second voltage level Vss, and the second voltage level Vss may be higher than the third voltage level -Vn (+Vp>Vss>-Vn).

[0071] For example, the first voltage level +Vp may be a positive (+) voltage. The second voltage level Vss may be 0 or a ground potential. The third voltage level -Vn may be a negative (-) voltage.

[0072] The first signal portion or time period V1 and third signal portion or time period V3 may alternate. The second signal portion or time period V2 may be between the first signal portion or time period V1 and the third signal portion or time period V3. Alternatively, the second signal portion or time period V2 may be before the first signal portion or time period V1 and/or after the third signal portion or time period V3.

[0073] In each period T of the driving signal Vd, the first signal portion, value and/or time period V1, the second signal portion, value and/or time period V2, and the third signal portion, value and/or time period V3 may be referred to as a "first portion or time period Ta1", a "second portion or time period Ta2", and a "third portion or time period Ta3", respectively.

[0074] Thus, each period T of the driving signal Vd may include the first portion or time period Ta1, second portion or time period Ta2, and third portion or time period Ta3. In each period T, the second portion or time period Ta2 may be present between the first period Ta1 and the third period Ta3.

[0075] The second portion or time period Ta2 present between the first portion or time period Ta1 and the third portion or time period Ta2 may be shorter than the first portion or time period Ta1 or the second portion or time period Ta2.

[0076] The first portion or time period Ta1 and third portion or time period Ta3 may be equal. Of course, embodiments of the present disclosure are not limited to the above-described condition. In another embodiment, the first portion or time period Ta1 and third portion or time period Ta3 may differ from each other.

[0077] The driving signal Vd may have a duty ratio DR more than 0.25, but less than 1 (0.25<DR<1). That is, the duty ratio DR of the driving signal Vd may be within a range of more than 0.25, but less than 1. When the duty ratio DR of the driving signal Vd is not more than 0.25, the average power of the driving signal Vd to be transmitted may be reduced by 1/4. In this case, touch performance may be reduced by 6 dB or more.

[0078] The duty ratio DR of the driving signal may be the rate of the sum of the first portion or time period Ta1 and third portion or time period Ta3 (Ta1+Ta3) within each period T of the driving signal ((Ta1+Ta3)/T), as compared to the second portion or time period Ta2.

[0079] Dotted line portions in FIG. 2 illustrate a driving signal VE having two voltages of different levels. The driving signal VE transits from the first voltage level V+p to the third voltage level -Vn every half period T/2. At the half period time T/2, the driving signal VE may transition from Vp to Vn.

[0080] On the other hand, in one or more embodiments of the present disclosure, the driving signal Vd at a first time t1 may transition from a first value Vp. The driving signal Vd at a second time t2 may transition to a value Vn.

[0081] That is, the transition from Vp or to Vn of the driving signal Vd according to the illustrated embodiment(s) is less than the transition from Vp to Vn of the driving signal VE.

[0082] Thus, in the illustrated embodiment, it is possible to reduce one or more harmonic components of or in the driving signal Vd because the driving signal Vd has three or more voltages of different levels within each period thereof.

[0083] FIG. 4 illustrates examples of a driving signal having two voltages of different levels and a driving signal having three voltages of different levels in accordance with one or more embodiments of the present disclosure. FIG. 5 illustrates results of a simulation illustrating a harmonic component of the driving signal of FIG. 4 having two voltages of different levels. FIG. 6 illustrates results of a simulation illustrating a harmonic component of the driving signal according to embodiment(s) of the present disclosure illustrated in FIG. 4.

[0084] In FIG. 4, the solid line depicts the driving signal according to embodiment(s) of the present disclosure, and the dotted line depicts the driving signal that has two voltages of different levels.

[0085] Referring to FIGS. 4 to 6, it can be seen that the harmonic component(s) shown in FIG. 5 is less than that of FIG. 6.

[0086] In embodiments of the present disclosure, it is possible to provide the sensing unit with enhancements in sensitivity and jitter immunity of in accordance with the reduction of the harmonic component(s) in the driving signal.

[0087] Driving signals simultaneously applied to two or more of the driving lines may have the same phase.

[0088] For example, the driving signal Vd illustrated in FIG. 2 may be simultaneously applied to two or more of the driving lines at the same phase.

[0089] An overlapped or combined signal Vc (FIG. 3) received by the sensing unit 30 may be a signal having three voltages of different levels.

[0090] Here, the "overlapped or combined signal Vc" means a signal in accordance with results of overlap, summation or combination of driving signals applied to each sensing line (for example, Yj in FIG. 3) and/or coupled to sensing nodes corresponding to the driving lines receiving the driving signals.

[0091] FIG. 7 depicts a signal received by the sensing unit via each sensing line when driving signals having the same phase are simultaneously applied to two or more driving lines corresponding to the sensing line, respectively.

[0092] Referring to FIG. 7, when driving signals Vd simultaneously applied to two driving lines, for example, X1 and X2, have the same phase, the magnitude of the signal Vc (FIG. 3) received by the corresponding sensing line Y1 may be double the magnitude of the driving signal Vd applied to each driving line, for example, X1 or X2, in accordance with a principle of overlap, summation or combination.

[0093] On the other hand, voltage variation of the overlapped or combined signal Vc received by the sensing unit 30 may be less than a first voltage variation. The first voltage variation may be the voltage variation of a signal received by the sensing unit when a driving signal having two voltages of different levels and the same phase is simultaneously applied to two driving lines, for example, X1 and X2, respectively (hereinafter, referred to as a "first case").

[0094] The overlapped or combined signal Vc (FIG. 3) received by the sensing unit 30 may be a signal having three voltages of different levels. Furthermore, the overlapped or combined signal Vc (FIG. 3) received by the sensing unit 30 may have a fourth voltage level, +2Vp, the second voltage level Vss, and a fifth voltage level, -2Vn.

[0095] In embodiments of the present disclosure, it is possible to reduce the maximum peak current of the overlapped or combined signal Vc received by the sensing unit 30, as compared to the first case, and, as a result, the design specification of the sensing unit 30 may be relaxed, as compared to the first case.

[0096] In accordance with an increase in the magnitude of the overlapped or combined signal Vc (FIG. 9) received by the sensing unit 30, it is possible to achieve an enhancement in signal to noise ratio of the sensing signal Vs (FIG. 3) received by the sensing unit 30.

[0097] The phase of the driving signal applied to at least one of the selected driving lines may differ from the phases of the driving signals applied to the remaining driving lines.

[0098] For example, different phases of the driving signal Vd illustrated in FIG. 2 may be simultaneously applied to two or more driving lines.

[0099] FIG. 8 illustrates an example in which at least one driving signal simultaneously applied to driving lines has a phase different from those of the remaining driving signals.

[0100] Referring to FIG. 8, the driving signal applied to one or more of the driving lines (for example, an odd number of driving lines X1, X2, and X3, or just X2), may have a phase different from the driving signals applied to the remaining driving lines (for example, X1 and X3).

[0101] The driving signal applied to at least one of the driving lines may have a phase difference of 180.degree. or a half period from the driving signals applied to the remaining driving lines.

[0102] For example, the phases of the driving signals applied to the first and third driving lines X1 and X3 may be identical, while at the same time being different from that of the driving signal applied to the second driving line X2.

[0103] The sensing unit 30 may be electrically connected to the plural sensing lines Y1 to Ym (m being a natural number greater than 1). The sensing unit 30 may sense the capacitance of a node capacitor between a driving line and a corresponding or overlapping one of the sensing lines.

[0104] The driving unit 20 may supply the driving signal Vd to the driving lines X1 to Xn (n being a natural number greater than 1). The sensing unit 30 may include sensing circuits for sensing signals received by the sensing unit 30 via the sensing lines Y1 to Ym, respectively.

[0105] FIG. 3 is an embodiment of the sensing circuit 30-j included in the sensing unit 30 illustrated in FIG. 1.

[0106] Although only one sensing circuit 30-j, coupled to the i-th driving line Xi and the j-th sensing line Yj, is illustrated in FIG. 3, the sensing unit 30 may include a plurality of sensing circuits coupled to m sensing lines Y1 to Ym (m being a natural number greater than 1).

[0107] Referring to FIG. 3, the sensing circuit 30-j may include an amplifier 31 and a capacitor 32.

[0108] The amplifier 31 may be a differential amplifier having a first input terminal 201 (for example, an inverting or negative terminal) coupled to the sensing line Yj, a second input terminal 202 (for example, non-inverting or positive terminal) connected to the second voltage level Vss, and an output terminal 203 for outputting a sensing signal Vs. Although an operational amplifier is illustrated as an example of the amplifier 31 in FIG. 3, embodiments of the present disclosure are not limited thereto.

[0109] The capacitor 32 is electrically connected between the first input terminal 201 and the output terminal 203 of the amplifier 31, to negatively feed back an output from the amplifier 31 to the first input terminal 201. The capacitor 32 may also determine a gain of the sensing signal Vs.

[0110] The signal Vc received by the sensing circuit 30-j may be a signal obtained by overlapping two or more driving signals simultaneously driven through the sensing line Yj.

[0111] That is, two or driving signals, which are simultaneously driven, may overlap in the sensing line Yj and, as such, an overlapped or combined signal, namely, the signal Vc, may be received by the sensing unit 30.

[0112] The control unit controls operations of the driving unit 20 and sensing unit 30.

[0113] For example, the control unit 40 may generate a driving control signal Sx for control of the driving unit 20, and a sensing control signal Sy for control of the sensing unit 30. The control unit 40 controls operations of the driving unit 20 and sensing unit 30 in accordance with the driving control signal Sx and sensing control sign al Sy.

[0114] The control unit 40 may sense the signal Vc applied to the sensing line Yj, and may control the sensing unit 30 in accordance with the sensed results, to output the sensing signal Vs.

[0115] As described above, in accordance with the embodiment, it is possible to reduce a harmonic component included in the driving signal while achieving an enhancement in sensitivity and jitter immunity by applying a driving signal having three voltages of different levels to two or more driving lines. This is because separate detection of a desired signal and a noise signal can be easily achieved in accordance with reduction of the harmonic component included in the driving signal.

[0116] In addition, in accordance with the embodiment, it is possible to compensate for a delay time due to parasitic capacitance caused by the touch panel 10 and substrate (for example, a printed circuit board (PCB)). Accordingly, stable operation of the touchscreen device 100 can be ensured.

[0117] Moreover, in accordance with the embodiment, momentary peak current can be reduced through a reduction in voltage variation of the driving signal Vd. Accordingly, it is possible to eliminate glitch of the signal received by the sensing unit, and to easily realize the circuit of the sensing unit 30.

[0118] FIG. 9 is a method for simultaneously driving two driving lines in accordance with one or more embodiments.

[0119] Referring to FIG. 9, two driving lines selected from among a plurality of driving lines X1 to Xn (n being a natural number greater than 1; for example, the driving lines X1 and X2) can be simultaneously driven. Each of the driving signals for simultaneous driving of the two selected driving lines (for example, driving signals Vd1 and Vd2 for the driving lines X1 and X2) may have voltages of different levels.

[0120] In the illustrated embodiment, the overlapped or combined signal Vc received by the sensing unit 30 may have three voltages of different levels via the sensing line (for example, Y1) through adjustment of the phases and/or adjustment, combination and/or summation of voltage levels of the driving signals, each having two voltages of different levels. The overlapped or combined signal Vc may be a periodic signal having a certain period T.

[0121] Here, the "overlapped or combined signal Vc" generally means a signal in accordance with results of overlap, combination and/or summation of driving signals (for example, Vd1 and Vd2) applied to each sensing line (for example, Y1 in FIG. 3) coupled to sensing nodes (for example, C11 and C21 in FIG. 3) corresponding to two driving lines (for example, X1 and X2) receiving the driving signals.

[0122] The overlapped or combined signal Vc received by the sensing unit 30 may be a periodic signal.

[0123] The period T of the overlapped or combined signal Vc may be divided into first to fourth portions or time periods T1 to T4, which are sequential. The signal Vc overlapped or combined for one period T may sequentially include a first section, portion or time period having a first voltage level, a second section, portion or time period having a second voltage level, a third section, portion or time period having a third voltage level, and a fourth section, portion or time period having the second voltage level.

[0124] The first voltage level, second voltage level, and third voltage level are different from each other. The first voltage level may be highest, the third voltage level may be lowest, and the second voltage level may be between the first and third voltage levels (Va1>Va2>Va3).

[0125] For example, the first voltage level may be a positive (+) voltage. The second voltage level may be 0 or a ground potential. The third voltage level may be a negative (-) voltage.

[0126] For example, the overlapped or combined signal Vc received by the sensing unit 30 may include a first signal portion or time period Va1 having the first voltage level, a second signal portion or time period Va2 having the second voltage level, and a third signal portion or time period Va3 having the third voltage level.

[0127] The first signal portion or time period Va1 and third signal portion or time period Va3 may alternate. The second signal portion or time period Va2 may be between the first signal portion or time period Va1 and the third signal portion or time period Va3.

[0128] For example, the overlapped or combined signal Vc may be the first signal portion or time period Va1 during the first period T1, the second signal portion or time period Va2 during the second period T2, the third signal portion or time period Va2 during the third period T3, and the fourth signal Va4 during the fourth period T4. The fourth signal Va4 during the fourth period T4 may have the same voltage and/or length as the second signal portion or time period Va2 during the second period T2.

[0129] The voltage of the driving signal supplied to one of the two driving lines during the first period T1 may be the first voltage level, and the voltage of the driving signal supplied to the other driving line during the first period T1 may be the second voltage level. Alternatively, the voltages of the driving signals respectively supplied to the two driving lines during the first period T1 may be the first voltage level.

[0130] For example, the voltages (for example, A1 and B1) of the driving signals Vd1 and Vd2 respectively supplied to two driving lines (for example, X1 and X2) during the first period T1 may be voltages (+, 0) or voltages (+, +), respectively.

[0131] The voltage of the driving signal supplied to one of the two driving lines during the second period T2 or during the fourth period T4 may be the first voltage level, and the voltage of the driving signal supplied to the other driving line during the second period T2 or during the fourth period T4 may be the third voltage level. Alternatively, the voltages of the driving signals respectively supplied to the two driving lines during the second period T2 or during the fourth period T4 may be the second voltage level.

[0132] For example, the voltages (for example, A2 and B2) of the driving signals Vd1 and Vd2 respectively supplied to two driving lines (for example, X1 and X2) during the second period T2 may have voltages (0, 0) or voltages (+, -), respectively. On the other hand, the voltages (for example, A4 and B4) of the driving signals Vd1 and Vd2 respectively supplied to two driving lines (for example, X1 and X2) during the fourth period T4 may have voltages (0, 0) or voltages (+, -) or (-, +), respectively.

[0133] The voltage of the driving signal supplied to one of the two driving lines during the third period T3 may be the third voltage level, and the voltage of the driving signal supplied to the other driving line during the third period T3 may be the second voltage level. Alternatively, the voltages of the driving signals respectively supplied to the two driving lines during the third period T3 may be the third voltage level.

[0134] For example, the voltages (for example, A3 and B3) of the driving signals Vd1 and Vd2 respectively supplied to two driving lines (for example, X1 and X2) during the third period T3 may have voltages (-, -) or voltages (-, 0), respectively.

[0135] Here, "+" represents the first voltage level, "0" represents the second voltage level, and "-" represents the third voltage level.

[0136] Although FIG. 9 illustrates an example in which two driving lines are simultaneously driven, embodiments of the present disclosure are not limited thereto.

[0137] For example, the overlapped or combined signal Vc received by the sensing unit 30 during each of the periods T1 to T4 may have voltages as illustrated in FIG. 9, through adjustment of the phases and/or adjustment, combination and/or summation magnitudes of the driving signals respectively supplied to the two or more driving lines. One skilled in the art can add or combine one or more additional signals having a phase and/or magnitude as shown in any of FIGS. 10A-C, or a smaller magnitude (for example as provided by a conventional voltage divider), to form an overlapped or combined signal having more than 3 voltage levels.

[0138] FIGS. 10A to 10C illustrate examples of two driving signals Vd1 and Vd2 illustrated in FIG. 9 that overlap or are combined, added or summed to form the overlapped or combined driving signal Vc.

[0139] Referring to FIGS. 10A to 10C, each of the first and second driving signals Vd1 and Vd2 may have two voltages from among the first voltage level +Vp, second voltage level Vss, and third voltage level -Vn.

[0140] The overlapped or combined signal Vc received by the sensing unit 30 during each of the periods T1 to T4 may have three voltages of different levels, Vap, Vss, and Van, in one period T, through adjustment, combination and/or summation of the phases and/or magnitudes of the first and second driving signals Vd1 and Vd2.

[0141] FIG. 11 illustrates a method for simultaneously driving two driving lines in accordance with another embodiment.

[0142] Referring to FIG. 11, each of the driving signals Vd1 and Vd2 for simultaneous driving of two selected driving lines (for example, the driving lines X1 and X2) may have voltages of different levels.

[0143] In addition, each driving signal Vd1 and Vd2 for simultaneous driving of the two selected driving lines (for example, the driving lines X1 and X2) may be a periodic signal having a certain period. The driving signals Vd1 and Vd2 may have the same phase.

[0144] The first and second driving signals Vd1 and Vd2 may have the same voltage in each of the first to fourth periods T1 to T4.

[0145] For example, the voltage of each of the first and second driving signals Vd1 and Vd2 in the first period T1 may be the first voltage level +Vp. The voltage of each of the first and second driving signals Vd1 and Vd2 in the second period T2 and/or in the fourth period T4 may be the second voltage level Vss. The voltage of each of the first and second driving signals Vd1 and Vd2 in the third period T3 may be the third voltage level -Vn.

[0146] In this embodiment, the overlapped or combined signal Vc received by the sensing unit 30 may have three voltages of different levels through adjustment of the phases and/or adjustment, combination and/or summation of the magnitudes of two driving signals (for example, Vd1 and Vd2).

[0147] Since the overlapped or combined signal Vc received by the sensing unit 30 has three voltages of different levels, it is possible to reduce a harmonic component of the overlapped or combined signal Vc. As result, the filter specification for signal detection may be relaxed. In addition, when the driving signals Vd1 and Vd2 have the same phase, it is possible to reduce influence caused by interference of driving lines (for example, X1 and X2.

[0148] Although embodiments of the present disclosure have been described with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More particularly, variations and modifications are possible in the component parts and/or arrangements of the subject combination and/or arrangement within the scope of the disclosure, the drawings and the appended claims. In addition to variations and modifications in the component parts and/or arrangements, alternative uses will also be apparent to those skilled in the art.

Claims

1. A method for driving a touch panel including driving lines, sensing lines, and node capacitors between neighboring and/or overlapping driving lines and sensing lines, comprising: selecting two or more of the driving lines; and simultaneously driving the selected driving lines with driving signals, wherein each driving signal has three or more voltages of different levels.

2. The method according to claim 1, wherein each driving signal is a periodic signal, and has three voltages of different levels during each period.

3. The method according to claim 2, wherein: each driving signal comprises: a first signal portion or time period having a first voltage level, a second signal portion or time period having a second voltage level, and a third signal portion or time period having a third voltage level; and the first voltage level, the second voltage level, and the third voltage level are different from each other.

4. The method according to claim 3, wherein the first voltage level is higher than the second voltage level, and the second voltage level is higher than the third voltage level.

5. The method according to claim 4, wherein the first voltage level is a positive (+) voltage, the second voltage level is 0 or a ground potential, and the third voltage level is a negative (-) voltage.

6. The method according to claim 4, wherein the first signal portion or time period and the third signal portion or time period alternate, and the second signal portion or time period is between the first signal portion or time period and the third signal portion or time period.

7. The method according to claim 3, wherein: each driving signal has a duty ratio within a range of more than 0.25, but less than 1; and the duty ratio of each driving signal is a ratio or percentage of a sum of a length of the first period and a length of the third signal portion or time period in each period of the driving signal.

8. The method according to claim 1, wherein the driving signals have a same phase.

9. The method according to claim 1, wherein the driving signal applied to at least one of the selected driving lines has a phase different from the driving signals applied to remaining driving lines.

10. The method according to claim 3, wherein the first signal portion or time period and the third signal portion or time period of each driving signal have equal lengths.

11. The method according to claim 6, wherein the second signal portion or time period is before the first signal portion or time period and/or after the third signal portion or time period.

12. A method for driving a touch panel including driving lines, sensing lines, and node capacitors between neighboring and/or overlapping driving lines and sensing lines, comprising: selecting two or more of the driving lines; and simultaneously driving the selected driving lines with driving signals, wherein each driving signal is a periodic signal having a period comprising a first portion or time period in which the driving signal has a first voltage level, a second portion or time period in which the driving signal has a second voltage level lower than the first voltage level, and a third period in which the driving signal has a portion or time third voltage level lower than the second voltage level.

13. The method according to claim 12, wherein: each driving signal has a duty ratio within a range of more than 0.25, but less than 1; and the duty ratio of each driving signal is a ratio or percentage of a sum of a length of the first portion or time period and a length of the third portion or time period in each period of the driving signal.

14. The method according to claim 12, wherein at least a portion of the second portion or time period is between the first portion or time period and the third portion or time period.

15. The method according to claim 14, wherein a length of the first portion or time period and a length of the third portion or time period are equal.

16. The method according to claim 14, wherein the portion of the second portion or time period between the first portion or time period and the third portion or time period is shorter than the first portion or time period or the third portion or time period.

17. The method according to claim 12, wherein the driving signals have a same phase.

18. The method according to claim 12, wherein the driving signal applied to at least one of the selected driving lines has a phase different from the driving signals applied to remaining driving lines.

19. A method for driving a touch panel including driving lines, sensing lines, and node capacitors between neighboring and/or overlapping driving lines and sensing lines, comprising: selecting two or more of the driving lines; simultaneously driving the selected driving lines with driving signals having two voltages of different levels; and receiving an overlapped or combined signal of the simultaneously-driven driving signals, wherein the overlapped or combined signal is a periodic signal having three or more voltages of different levels.

20. The method according to claim 19, wherein the overlapped or combined signal has a period sequentially comprising a first portion or time period in which the overlapped or combined signal has a first voltage level, a second portion or time period in which the overlapped or combined signal has a second voltage level lower than the first voltage level, a third portion or time period in which the overlapped or combined signal has a third voltage level lower than the second voltage level, and a fourth portion or time period in which the overlapped or combined signal has the second voltage level.