KR20160150630A - Touch singla detection apparatus and touch signal detection method - Google Patents

Abstract

The present invention relates to an electrostatic touch input device of a human finger or a touch input means having conductive characteristics similar thereto and, more particularly, to a touch signal detection device for improving touch detection resolution by minimizing or excluding signal interference between touch detection signals upon detecting touch signals and a touch signal detection method. According to the touch signal detection device and the touch signal detection method of the present invention, the touch detection resolution is improved by removing interference between the touch signals even in the case of multi-touch. According to the touch signal detection device and the touch signal detection method of the present invention, the touch signal is easily detected and the display quality of a display device is maximized by minimizing an effect on the display device.

Description

TECHNICAL FIELD [0001] The present invention relates to a touch signal detecting apparatus and a touch signal detecting method.

The present invention relates to an electrostatic touch input device of a touch input means having a finger or a similar conductive characteristic of the body, and more particularly, to a touch input device which minimizes or eliminates signal interference between touch detection signals And to a touch signal detecting method and a touch signal detecting method.

Generally, a touch screen panel is attached to a display device such as a liquid crystal display (LCD), a plasma display panel (PDP), an organic light emitting diode (OLED), or an active matrix organic light emitting diode (AMOLED) And is an input device that generates a signal corresponding to a position when an object such as a finger or a pen is touched. The touch screen panel is used in a wide range of fields such as a small portable terminal, an industrial terminal, and a DID (Digital Information Device).

Conventionally, various types of touch screen panels have been disclosed, but resistance type touch screen panels having a simple manufacturing process and a low manufacturing cost have been widely used. However, since the resistance type touch screen panel has low transmittance and must be applied with pressure, it is inconvenient to use, and it is difficult to recognize multi-touch and gesture, and detection error occurs.

On the other hand, capacitive touch screen panels are increasingly penetrating the market because of their high transmittance, soft touch recognition, and good multi-touch and gesture recognition.

1 shows an example of a conventional capacitive touch screen panel. 1, a transparent conductive film is formed on the upper and lower surfaces of a transparent substrate 2 made of plastic or glass, and metal electrodes 4 for voltage application are formed on each of four corners of the transparent substrate 2. The transparent conductive film is formed of a transparent metal such as ITO (Indium Tin Oxide) or ATO (Antimony Tin Oxide). The metal electrodes 4 formed at the four corners of the transparent conductive film are formed by printing with a conductive metal having a low resistivity such as silver (Ag). A resistor network is formed around the metal electrodes 4. The resistance network is formed with a linearization pattern for uniformly transmitting a control signal to the entire surface of the transparent conductive film. A protective film is coated on the transparent conductive film including the metal electrode 4.

When a high frequency AC voltage is applied to the metal electrode 4, the electrostatic touch screen panel is spread over the front surface of the transparent substrate 2. At this time, if the transparent conductive film on the upper surface of the transparent substrate 2 is lightly touched by the finger 8 or the conductive touch inputting means, a certain amount of current is absorbed into the body and the current sensor incorporated in the controller 6 senses the change of current, The touch points are recognized by calculating the amount of current in each of the metal electrodes 4.

However, since the electrostatic touch screen panel as shown in FIG. 1 is a method of detecting the magnitude of the minute current, an expensive sensing device is required, so that the price rises and multi-touch which recognizes a plurality of touches is difficult.

In order to overcome such a problem, a capacitive touch screen panel as shown in FIG. 2 has been used in recent years. The touch screen panel of FIG. 2 includes a horizontal linear touch pad 5a and a longitudinal linear touch pad 5b, and a touch drive IC 7 for analyzing a touch signal. This touch screen panel detects the magnitude of the capacitance formed between the linear touch pad 5 and the finger 8. The horizontal linear touch pad 5a and the longitudinal linear touch pad 5b are scanned So that a plurality of touch points can be recognized.

However, when the touch screen panel is mounted on a display device such as an LCD, it is difficult to detect a signal due to noise. For example, in the LCD, a common electrode to which a common voltage Vcom applied in common to a liquid crystal is applied, a common voltage is affected by a pixel voltage applied to the liquid crystal, The common voltage Vcom of the touch point acts as a noise at the touch point detection.

In addition, by scanning the horizontal linear touch pad 5a and the vertical linear touch pad 5b in order to obtain the touch signal, the scan signal is obtained The image quality may be affected due to the influence of the common voltage.

Figure 3 shows an embodiment in which a conventional capacitive touch screen panel is mounted on an LCD. The display device 200 has a structure in which a liquid crystal is enclosed between the TFT substrate 205 on the lower side and the color filter 215 on the upper side to form the liquid crystal layer 210. The TFT substrate 205 and the color filter 215 are bonded to each other by the sealant 230 at the outer portion thereof. Although not shown, a polarizing plate is attached to the upper and lower sides of the liquid crystal panel, and a BLU (Back Light Unit) is installed thereon.

As shown in the figure, a touch screen panel is installed on the display device 200. The touch screen panel has a structure in which the linear touch pad 5 is mounted on the upper surface of the substrate 1. [ On the substrate 1, a protective panel 3 for protecting the linear touch pad 5 is attached. The touch screen panel is adhered to an edge portion of the display device 200 via an adhesive member 9 such as DAT (Double Adhesive Tape) or the like, and forms an air gap 9a with the display device 200.

In this configuration, when a touch as shown in FIG. 3 occurs, a capacitance such as Ct is formed between the finger 8 and the linear touch pad 5. As shown in the drawing, a capacitance equal to the common electrode capacitance Cvcom is formed between the linear touchpad 5 and the common electrode 220 formed on the lower surface of the color filter 215 of the display device 200, (Cp), which is an unknown parasitic capacitance due to a capacitance coupling between the patterns or a manufacturing process factor, is also applied to the capacitor 5. Therefore, a circuit similar to that of the equivalent circuit of Fig. 4 is constructed.

Here, the conventional touch screen panel detects the touch by detecting the change amount of the touch capacitance Ct, and the components such as Cvcom and Cp act as noise in the detection of Ct. In particular, since the common electrode capacitance Cvom is sometimes ten times larger than the touch capacitance Ct, there is a problem that the touch sensitivity is lowered due to the distortion of the touch signal due to the shaking of the Cvcom and the problem that the capacitance Ct is ten times larger than the touch capacitance Ct .

To solve this problem, a new structure of touch detection method is proposed which reduces Cvom. FIG. 5 shows an embodiment of a method for reducing Cvcom. FIG. 5 illustrates a method of reducing the Cvcom since the linear sensor of FIG. 2 is divided into several sensors. Thus, the above-described sensitivity reduction and influence on the display device can be solved. However, since the number of the touch pads 10 is larger than that of the linear sensors 5 in FIG. 2, it is necessary to detect the touch signals in the plurality of touch pads 10 to satisfy the report time At this time, when a touch signal is simultaneously detected in Row signals (Col1, Row1) and (Cool1, Row2) adjacent to the same column, a parasitic power interruption There is a problem that interference of the touch signal occurs due to the capacitance Cp.

FIG. 6 shows an embodiment in which the touch signal is interfered when touch signals are simultaneously detected in (C1, R1) 22-a and (C1, R2) 22-b. Referring to FIGS. 5 and 6, the sensing pad signal line 22a of FIG. 6 is connected to the touch driver IC (TDI) adjacent to each other in FIG. 5, and parasitic capacitance Cp is formed between lines. (C1, R1) and (C1, R1) through the parasitic capacitance Cp when the touch signal is detected in the touch pad (C1, R1) of FIG. 6 using the driving back phenomenon (see Patent Application No. 2012-0109309) R2) are mutually influenced, an error of touch signal detection occurs.

Application number: 2012-0109309 Title: Touch detection means, detection method and touch screen panel using driving back phenomenon and display device incorporating such touch screen panel.

The present invention has been proposed in order to solve the problems of the conventional touch screen panel as described above, and it is an object of the present invention to provide a touch detection apparatus and a touch detection method thereof that prevent signal interference between touch pads 10 when a plurality of touch pads 10 detect a touch signal. And a touch detection method.

According to an aspect of the touch-signal detecting apparatus according to the present invention,

A touch signal detecting apparatus for detecting whether or not a touch is generated by sensing a touch capacitance which is added to an upper surface of a display device and is generated by an approach of a touch input means such as a finger of a user or a similar conductor,

And a touch detector connected to each of the touch pads for detecting the touch signal received through a plurality of touch signal lines for transmitting a touch signal to determine whether or not the conductor is touched,

Wherein the touch detection unit sequentially detects the touch signal in units of columns of the touch pad and each column of the touch pad detects at least one sensing pad and a plurality of non- -sensing pad).

Preferably,

The sensing pad is a touch pad for detecting a touch signal in the touch detection unit, and the non-sensing pad is a touch pad that does not detect a touch signal in the touch detection unit.

Preferably,

The non-sensing pad is connected to a ground potential or a ground potential or a constant DC voltage.

Preferably,

And the positions of the rows of at least one of the sensing pads when the touch signal is detected are different for each column.

Preferably,

And the positions of the rows of at least one of the sensing pads are the same for each column when the touch signal is detected.

Preferably,

And a separation signal line having a ground potential or a ground or a DC voltage is disposed between the sensing pads when the positions of the rows of the at least one sensing pad are the same for each column.

Preferably,

And the plurality of non-sensing pads are located between the at least one sensing pads.

Preferably,

The nano-sensing pad is connected to a ground potential or a ground potential or a constant DC voltage.

Preferably,

The sensing pad is one for each column, and the rest is an n-sensing pad.

Preferably,

The nano-sensing pad is connected to a ground potential or a ground potential or a constant DC voltage.

Preferably,

And the non-sensing pads are connected so as to have the same potential.

Preferably,

The touch signal detecting device

Charging means for charging the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct formed between the touch pad and the touch input tool, which are present in the touch pad;

An alternating voltage application unit for applying an alternating voltage to the touch pad; And

And a level shift detector for comparing a voltage variation of the touch detection sensor when a touch is not generated with a voltage variation of the touch detection sensor when the touch is generated.

Preferably,

The charging means is turned off so that the alternating voltage is applied in a state in which the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct are maintained in a floating state .

Preferably,

And the input terminal of the level shift detecting unit maintains a high impedance (Hi-Z) state when it is determined that the touch is detected.

Preferably,

Wherein the voltage level change in the touch pad when the touch is generated is smaller than the voltage level change in the case where no touch occurs.

Preferably,

The voltage variation in the touch pad during the touch generation and the voltage variation in the touch pad during the non-touch occurrence are generated in conjunction with the rising edge and the falling edge of the applied alternating voltage.

According to an aspect of the touch-signal detecting apparatus according to the present invention,

1. A touch signal detecting apparatus for detecting whether or not a touch is detected in a plurality of touch pads arranged in a matrix form,

A plurality of multiplexers connected to a plurality of touch pads of each column for receiving touch signals through a plurality of touch signal lines transmitting touch signals generated from the touch pads;

A selection signal generator for generating at least one selection signal for selecting one of the touch signals received by the multiplexer;

And a touch detector for detecting the touch signal selected by the selection signal and determining whether the touch signal is touched.

Preferably,

Wherein at least one of the plurality of multiplexers used in the touch signal detecting apparatus has the same configuration of the input and the output, and the number of the same output, the number of the same selection signal, and the order of the input signal selected for the arbitrary selection signal are the same do.

Preferably,

And the number of touch signals that can be accommodated in each of the multiplexers is equal to the number of touch pads of each column.

Preferably,

And the touch signal lines inputted to the respective multiplexers are arranged with a direction according to the positions of the touch pads of the respective columns.

Preferably,

Wherein the directionality is determined by the number of input pins of the touch signal line input to each of the multiplexers as the row number of the touch pad of each column increases or the row number of the touch pad of each column increases, As the number decreases, the number of input pins of the touch signal line input to each of the multiplexers decreases.

Preferably,

Each of the multiplexers receives the touch signal through a touch signal line connected to the touch pad belonging to the same column and does not receive an input from a touch signal line connected to the touch pad belonging to another column.

Preferably,

And the selection signal generated by the selection signal generator is commonly applied to each of the multiplexers.

Preferably,

And the selection signal is configured to output only one of the inputs of the multiplexer.

Preferably,

Wherein the touch pad corresponding to the one output selected by the selection signal is a sensing pad and it is determined whether the touch pad is touched by the touch detection unit and the remaining touch pads other than the sensing pad are non- pad or a ground potential or a DC potential.

Preferably,

The touch signal detecting device

Charging means for charging the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct generated by the appearance of the conductor existing in the touch pad; And

An alternating voltage application unit for applying an alternating voltage to the touch pad;

And a level shift detector for comparing a voltage variation of the touch detection sensor when a touch is not generated with a voltage variation of the touch detection sensor when the touch is generated.

Preferably,

The charging means is turned off so that the alternating voltage is applied in a state in which the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct are maintained in a floating state .

Preferably,

And the input terminal of the level shift detecting unit maintains a high impedance (Hi-Z) state when it is determined that the touch is detected.

Preferably,

Wherein the voltage level change in the touch pad when the touch is generated is smaller than the voltage level change in the case where no touch occurs.

Preferably,

The voltage variation in the touch pad during the touch generation and the voltage variation in the touch pad during the non-touch occurrence are generated in conjunction with the rising edge and the falling edge of the applied alternating voltage.

According to an aspect of the touch signal detecting method according to the present invention,

1. A touch signal detecting method for detecting touch in a touch pad including a plurality of touch pads arranged in a matrix form,

And a touch detecting step of detecting the touch signal received through the plurality of touch signal lines connected to the respective touch pads by the touch detecting unit and transmitting the touch signal to determine whether or not the conductive object is touched,

Wherein the touch detection step sequentially detects the touch signal in a column unit of the touch pad, wherein each column of the touch pad detects at least one sensing pad and a plurality of non-sensing pads non-sensing pad).

Preferably,

The touch detection step

A charging step of charging the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct generated by the appearance of the conductor by the charging means; And

An alternate voltage application step of applying an alternate voltage to the touch pad by an alternate voltage application unit;

And a level shift detecting step of comparing the voltage variation in the touch detection sensor when the touch failure occurs with the level shift detection unit and the voltage variation in the touch detection sensor when the touch is generated.

Preferably,

The charging means is turned off so that the alternating voltage is applied in a state in which the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct are maintained in a floating state .

According to the touch detection apparatus and the touch detection method according to the present invention, there is no interference between touch signals even in the case of multi-touch, so that the touch detection resolution is improved.

The touch detection device and the touch detection method according to the present invention have the effect of maximizing the display quality of the display device by easily detecting the touch signal and minimizing the influence on the display device.

1 is a perspective view illustrating an example of a conventional touch screen panel.
2 is a plan view showing another example of a conventional touch screen panel
Fig. 3 is a sectional view showing an example in which the touch screen panel of Fig. 2 is installed on a display device
Fig. 4 is an equivalent circuit diagram for detecting the touch capacitance in Fig. 3
5 illustrates an embodiment of a method for reducing the common voltage Vcom in a touch screen panel
FIG. 6 is a diagram illustrating a case where interference of a touch signal occurs when touch signals are simultaneously detected from two adjacent touch pads
7 is a block diagram for explaining a configuration of a touch detection apparatus 200 according to an embodiment of the present invention.
FIG. 8 is a view for explaining an embodiment in which interference due to parasitic capacitance between adjacent sensor signal lines is solved according to an embodiment of the present invention
FIG. 9 is a view for explaining a method of solving the problem of widening a width of a sensor signal line according to an embodiment of the present invention
10 is a block diagram of an embodiment of the use of a multiplexer according to an embodiment of the present invention

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

In order to fully understand the present invention, operational advantages of the present invention, and objects achieved by the practice of the present invention, reference should be made to the accompanying drawings and the accompanying drawings which illustrate preferred embodiments of the present invention.

Hereinafter, the present invention will be described in detail with reference to the preferred embodiments of the present invention with reference to the accompanying drawings. Like reference symbols in the drawings denote like elements.

The display device referred to in the present invention means any one of LCD, PDP, and OLED, or any other means for displaying other images.

Among the display devices listed above, the LCD requires a common voltage (Vcom) for driving the liquid crystal. For example, in a small and medium sized LCD for a portable device, a line inversion method in which a common voltage of a common electrode is alternated for one or a plurality of gate lines is used in order to reduce current consumption. As another example, a large LCD uses a dot inversion driving method in which the common voltage of the common electrode has a constant DC level. As another example, in the case of the transverse electric field mode LCD, the common electrode is formed in a part of the TFT substrate constituting the LCD, and the image is displayed by the line inversion or the dot inversion driving method. In the case of the transverse electric field mode LCD, a back ground is formed commonly in the entire color filter which is exposed to the outside through the back ITO, and is grounded to the ground signal for ESD blocking.

In the present invention, in addition to the electrode to which the common voltage Vcom is applied as described above, all the electrodes that commonly function in the display device are referred to as " common electrodes ", and alternate voltage, DC voltage, The voltage in the form of alternating in frequency will be referred to as " common voltage ".

The present invention detects a noncontact touch input of a finger or a touch input means having similar electrical characteristics. Here, the term " noncontact touch input " means that a touch input means such as a finger or the like touches the touch pad while being spaced apart from the touch pad by a substrate existing between the input means and the touch pad. The touch input means can be brought into contact with the outer surface of the substrate. In this case, however, the touch input means and the touch pad maintain the non-contact state. Accordingly, the touching action of the finger with respect to the touch pad can be expressed by the term " approach ". On the other hand, since the finger may be in contact with the outer surface of the substrate, the touching action of the finger with respect to the substrate may be expressed by the term " contact ". &Quot; Approach " and " contact " are commonly used herein.

The components such as " to " described below are aggregates of unit function elements that perform specific functions. For example, when an amplifier of a signal is a unit functional element and an amplifier or signal converter The aggregate can be called a signal transformer. Also, " part " may be included in a larger element or " part, " or may include smaller elements and " parts. &Quot; Also, " part " may have its own CPU.

In the following drawings, thicknesses and regions are enlarged to clearly show layers and regions. Like reference numerals are used for like parts throughout the specification. Whenever a portion of a layer, region, substrate, or the like is referred to as being "on" or "over" another portion, it includes not only the case where it is "directly on" another portion, but also the case where there is another portion in between. Conversely, when a part is "directly over" another part, it means that there is no other part in the middle.

Further, the " signal " described in this specification refers to a voltage or a current collectively unless otherwise specified.

In the present specification, the term " capacitance " refers to a physical size and is used in the same sense as " capacitance ". On the other hand, a " capacitor " refers to an element having a capacitance that is a physical size.

In this specification, C, which is a symbol used as a symbol of a capacitor, is used as a code for designating a capacitor and also indicates a capacitance which is the size of a capacitor. For example, C1 is a code that refers to a capacitor, and it also means that the capacitance, which is the size of the capacitor, is C1.

The term " forcing a signal "in this specification means that the level of a signal which is maintained in a certain state is changed. For example, the on / off control terminal of the switching element Applying the signal means that the existing low level voltage is changed to the high level,

In this specification, the touch pad 10 is composed of a sensing pad 10a (a hatched touch pad in FIG. 9) and a non-sensing pad 10b (an empty touch pad in FIG. 9). The sensing pad 10a includes a touch pad 10 connected to the touch detection unit 14 to detect a touch among the plurality of touch pads 10 The non-sensing pad 10b is a touch pad 10 that is not connected to the touch detection unit 14 without performing touch detection (that is, whether or not the touch pad 10 A touch pad that is not judged). After the touch detection is completed, the sensing pad 10a is turned to the non-sensing pad 10b, and any non-sensing pad 10b is switched to the sensing pad 10a according to a predetermined order. Therefore, the sensing pads and the non-sensing pads are not fixed and are determined sequentially in a predetermined order. The Time Sharing Technique is an example of ordering. The sensing pad 10b may be connected to a zero voltage or ground or a DC power source having a predetermined size.

In this specification, the meaning of detecting a touch or a touch signal means the same. The voltage detected by the touch detection unit when a touch capacitance is not formed due to a conductor such as a finger touching or approaching the touch pad 10, Is detected by the touch capacitance Ct formed when the conductor such as the touch pad is opposed to the touch pad.

In this specification, a touch drive IC (Touch Drive IC) is shortened to TDI.

Also, in this specification, precharge and charge, precharge voltage and charge voltage are used in the same sense.

In this specification, sensor signal lines connecting the sensing pads to the sensing pads are the same unless otherwise noted. Unnecessary sensing signal pad lines connecting the non-sensing pads and the non-sensing pads are also used unless otherwise specified.

In this specification, a column is a direction toward a TDI 30 after sensor signal lines are formed in a group, and a row is a direction perpendicular to a column direction.

7 is a block diagram for explaining a configuration of the touch detection apparatus 200 according to an embodiment of the present invention. The touch sensing apparatus 200 according to an embodiment of the present invention includes a touch pad 10, a driving electrostatic capacity adjusting unit 41, an alternating voltage applying unit 42, a charging voltage applying unit, and a level shift detecting unit 14 5 corresponding to the touch detection unit 14).

First, the touch detection operation of the level shift detection unit 14 will be described. The touch pad 10 forms a touch capacitance Ct with a touch input tool such as a finger or a conductor as a patterned electrode on a substrate to detect a touch input. The touch pad 10 may be formed entirely of transparency.

For example, the touch pad 10 may be formed of a transparent material such as ITO (Indium Tin Oxide), ATO (Antimony Tin Oxide), CNT (Carbon Nano Tube), IZO (Indium Zinc Oxide) However, in another example, the touch pad 10 may be formed of metal.

The touch pad 10 outputs a signal corresponding to the touch state in response to the alternating voltage in a floating state after the charge is charged. For example, the touch pad 10 responds to an alternating voltage Vdrv at a predetermined frequency And outputs different level shift values when the touch input tool is touched and when it is not touched. The touch detection apparatus 200 may further include a charging means 12. [

The charging means 12 may be a three-terminal type switching element performing a switching operation in response to a control signal supplied to an on / off control terminal, or may be a linear element such as an OP-AMP for supplying a signal in accordance with a control signal. The touch capacitances Ct, parasitic capacitance Cp and driving capacitances Cdrv acting on the touch pad 10 are connected to the output terminal of the charging means 12, and when the charging means is turned on, When a certain charging voltage is applied, Ct, Cdrv, Cp, etc. are charged to the charging voltage. Thereafter, when the charging means 12 is turned off, signals charged to Ct, Cdrv, and the like are isolated in a charged state unless they are discharged separately. At this time, in order to stably isolate the charged signal, it is preferable that the input terminal of the level shift detecting unit, which will be described later, has a high impedance. However, it is possible to observe the touch input while discharging the signal charged in the Cdrv or the like, Or the impedance of the input terminal of the level shift detection unit may be low if rapid observation is possible at the start of discharge.

The charging means 12 is turned on and the charge charged in the touch pad 10 is isolated as the charging means 12 is turned off. This isolated state is referred to as a floating state. The level of the voltage is changed by the alternating voltage applied to the driving electrostatic capacitance externally from the charge of the charging signal isolated between the charging means 12 and the level shift detecting portion. The voltage level is different when a touch occurs and when a touch does not occur. This level difference before and after the touch is referred to as a level shift.

The driving capacitance adjusting unit 41 adjusts the driving electrostatic capacitance formed between the driving capacitance adjusting unit 41 and the touch pad 10.

The alternating voltage application unit 42 applies an alternating voltage. Specifically, the alternating voltage application unit applies an alternating voltage alternating at a predetermined frequency to the touchpad 10 to vary the potential at the touchpad 10.

The level shift detecting section detects a level shift caused by the alternating voltage Vdrv in the floating state. Specifically, the level shift detection unit can detect whether a level shift has occurred by measuring a voltage variation in the touch pad 10 at the time of occurrence of a non-touch and a voltage variation at the touch pad 10 at the time of occurrence of a touch. That is, the potential of the touch pad 10 is raised or lowered by the applied alternating voltage Vdrv. The voltage level fluctuation when the touch occurs is smaller than the voltage level fluctuation when the touch is not generated. Therefore, the level shift detection section detects the level shift by comparing the voltage levels before and after the touch.

The level shift detector 14 can acquire the touch signal based on the difference of the voltage variation in the touch pad 10 according to the alternating voltage before and after the touch generation.

The level shift detection section may be configured with various elements or combinations of circuits. For example, the level shift detecting unit may include an amplifying element for amplifying a signal at an output terminal of the touch pad 10, an analog to digital converter (ADC), a voltage to frequency converter (VFC), a flip- ), A buffer, a TR (Transistor), a TFT (Thin Film Transistor), a comparator, a DAC, or the like.

Hereinafter, terms used in FIG. 7 are defined as follows.

The touch capacitance Ct refers to a capacitance formed between the touch pad 10 and a touch input tool such as a hand. The parasitic capacitance Cp refers to the capacitance attached to the touch pad 10 and may include any parasitic capacitance generated by the layout of the touch pad 10, have.

The driving electrostatic capacitance Cdrv may exist in the TDI as an electrostatic capacitance formed in a path for supplying an alternating voltage Vdrv alternating at a predetermined frequency for each touch pad 10 and may exist separately outside the TDI.

The charging means 12 is a CMOS as one example of a switch, and a control signal Vg may be applied to the gate and a charge voltage may be applied to the source (or drain). In other embodiments of the present invention, other devices that can be switched rather than CMOS may be used.

The initial input unit of the level shift detection unit may include a voltage follower. In the voltage follow, the same signal as the input signal is output, and the input end has a high impedance (Hi-z) characteristic. The voltage follower can function as a buffer.

The charging means 12 is turned on to supply the charging voltage to charge the driving capacitance Cdrv, the touch capacitance Ct and the parasitic capacitance Cp. Thereafter, when the charging means 12 is turned off, the input terminal of the voltage follower is high impedance, so that the charged charge is isolated. Accordingly, the voltage Vnt of the touch pad 10 is maintained, Lt; / RTI > Thereafter, when the voltage of the alternating voltage Vdrv is raised or lowered, the voltage Vo at the output terminal of the touch pad 10 is raised or lowered in conjunction with the alternating voltage.

* Voltage variation (DELTA Vnt) in the touch pad 10 due to Cdrv at the time of non-touch occurrence is changed according to the following equation (1).

Since Ct is added in parallel to Cdrv when a touch is generated, the voltage variation (DELTA Vtc) in the touch pad 10 at the time of touch generation is changed by the following formula (2).

Here,? V is the voltage variation at the touch pad 10, Vh is the high level voltage of the alternating voltage, Vl is the low level voltage of the alternating voltage, Cdrv is the driving capacitance, Cp is the parasitic capacitance, The capacitance and Vpre are charge voltages. The sign after Vpre is "+" when the alternating voltage rises and the sign after Vpre is "-" when the alternating voltage falls.

As shown in Equations (1) and (2), a difference in voltage occurs due to the addition of the touch capacitance Ct to the denominator in relation to the difference ΔVnt before the touch generation, When the level shift is detected, it is possible to detect the touch signal.

In this level shift detection method, when touch signals are simultaneously detected at (C1, R1) and (C1, R2) in FIG. 5, two touch pads are connected due to the parasitic capacitance Cp formed between the sensor signal lines (1) and (2) are different from each other, resulting in an error of touch detection.

As one embodiment of a method for solving the problem that the touch signal detection failure occurs due to the parasitic capacitance existing between the sensor signal line 22 and the touch pad 10 and the sensor signal line 22, A separate signal line (a separate signal line 300) having a ground voltage, a zero voltage or a DC power of a predetermined size is inserted between the adjacent sensor signal lines and the touch pad. That is, the separate signal line (separation signal line 300) is inserted between the touch pads 10 of (C1, R1) and (C1, R2) (A separate signal line 300). The parasitic capacitance Cp of FIG. 6 formed between the adjacent sensor signal lines 22 is separated into two parasitic capacitances Cp1 and Cp2 by a separate signal line (separation signal line 300) do.

However, this method has a problem in that a separate signal line (a separate signal line 300) must be inserted between the sensor signal lines 22, so that the width of the path in which the sensor signal lines 22 are disposed is widened. That is, referring to FIG. 5, there is a problem that the width of a portion where the bundle 100 of the sensor signal line 22 passes is widened.

Fig. 9 is an embodiment for solving such a problem. 9, the hatched touch pad 10 of FIG. 9 is a sensing pad 10a for detecting a touch signal and the non-hatched touch pad 10 is a non-touch sensing sensing pad 10b, to be. The I sensing pad 10b is a DC voltage located between the sensing pads 10a and having a zero voltage, a ground voltage, or a predetermined magnitude. That is, at the time when the sensing pad 10a detects the touch signal, the non-sensing pad 10b is positioned between the sensing pads 10a, and the potential of the non-sensing pad 10b is the ground potential or the ground or DC voltage. The TDI 30 controls the non-sensing pad 10b to be connected to the ground potential or the ground or the DC voltage. At this time, the sensing pads 10a such as col1 and col2 can be shifted from each other, or it is possible to detect touch signals in the same row as col3 and col4. (C3, R1) and (C4, R1) are generated when touch signals are detected in the same row as col3 and col4. As shown in the figure, a DC line having a ground potential or a ground voltage or a DC voltage is disposed between the .

As shown in FIG. 9, when too many touch pads 10 detect a touch signal, it takes a certain time to detect the touch signal using the ADC, so that the touch signal can be lost. Of course, it is possible to detect the touch signal in a short time by using a large amount of ADC. However, if the number of ADC is increased, the volume of the TDI 30 increases and the consumption current increases.

In order to solve such a problem, the preferred embodiment has one sensing pad 10a in one column. At this time, of course, the potential of the non-sensing pad 10b is the ground potential / ground / DC potential. In addition, the potential of the sensing pad is the same. That is, the potential of the nonsensing pad 10b existing in the same column is all potential or all of the potentials of DC or both.

One method of extracting one sensing pad 10a from a plurality of touch pads included in one column is to use a multiplexer (mux). 10 is an embodiment relating to the use of a multiplexer. Although the embodiment of FIG. 10 has been described by way of example in the case of having five groups and including six touch pads 10 in one group, this is only one embodiment for explanation, More touch pads 10 can be added.

In the embodiment of FIG. 10, the group is a collection of touch pads 10 sharing the mux 31. The mux 31 is a 6in x 1out type that outputs one signal for each of six inputs. The mux 31in is a 20in x 1out (select one of 20 inputs) or 30in x 1out ≪ / RTI > select one of the inputs).

A select signal is required to select one of a plurality of signals input to the mux 31. Two selection signals are required to select one of the four input signals and three selection signals are required to select one of the eight input signals. In the embodiment of FIG. 10, since one output signal among six input signals must be determined, at least three selection signals are required, which are denoted by "A, B, C" Since the selection signal generator 400 is applied to all the muxes even if only one selection signal generator 400 is applied, the circuit for the selection signal generator becomes simple and the TDI 30 becomes simple. Signals are common to all muxes.

It is also preferable to use the same type of mux 31 for simplifying the circuit. The same type of mux means that 1) the number of identical inputs 2) the number of identical outputs 3) the number of identical selection signals 4) the case that the order of the input signals selected for any selection signal is the same (ie, HLL means that the fourth of the six signals input to the MUX is selected and this signal is output). The same selection signal is used for all muxes for this purpose.

Since the muxes of the present invention are all of the same type, the connection method of the touch pad 10 and the mux in the group connected to the mux 31 is also the same. Referring again to FIG. 10, Row 1 is allotted to input 1 of mux 30a and Row 2 is assigned to mux input 2. The last Row6 is assigned to mux input 6, and this wiring method is the same in all muxes. Since the present invention uses a plurality of muxes and uses the same selection signal, one input signal is selected in one mux. Therefore, the touch pad 10 in the same row is used for detecting the touch signal, except that the re-map method is not used. At this time, all the remaining touch pads 10 except for the touch pads 10 of the same row used for touch detection are connected to a ground potential or a predetermined DC potential. In addition, the potential of the nonsensing pad 10b is the same potential or the same ground or the same DC potential.

Referring again to FIG. 10, since one mux is used for one group, the input pins of the TDI 30 are assigned the same number of pins per group. For example, since there are six touch pads 10 in each of the five groups illustrated in FIG. 10, six connection pins are allocated to one group in the TDI 30. This means that the same number of pins as 1 through 6, 7 through 12 in FIG. 10 are allocated.

In addition, the TDI 30 has a group to which the same number of input pins are assigned. Referring to FIG. 10, six pins are assigned to five groups, with 1 to 6 being group 1, 7 to 12 being group 2, and 25 to 30 being group 5. In some cases, the number of pins may be increased by adding a few inputs to an arbitrary group, but it is also possible to use the same mux in this case.

In addition, they are arranged in the TDI 30 for each group. For example, between 1 and 6 input pins of TDI in which group 1 is placed, it is impossible for signals of 7 to 30, which are pins of another group, to intervene. This is a method for easily operating the ADC, the amplifier, and the like by using the same input signal by selecting the same input signal and using the touch pad 10 of the same row for detecting the touch signal. Therefore, the tendency that the selected row number increases (or decreases) as the pin number in the TDI 30 increases (or decreases) in each group is the same. That is, the tendency that the number of the selected row increases as the pin number of the TDI increases in the group 1 means that the same applies to all the groups.

In this situation, since the row and column selected for touch signal detection are regular, if the touch signal stored in the memory unit 28 mapped to each touch pad 10 is mapped, It is possible to perform an operation. For example, when a touch signal is detected at (C3, R3) and (C3, R4), this is a signal detected by two consecutive sensors, Since the signal is continuously stored in the corresponding memory, it is possible to obtain the touch coordinates without performing an arithmetic operation such as Re-map (a process of rearranging the touch signal stored in the memory unit to match the arrangement of the touch sensor) It means.

A touch signal detecting method according to the present invention is for detecting whether or not a touch is detected in a touch pad including a plurality of touch pads arranged in a matrix form.

The touch signal detecting method according to the present invention includes a touch detecting step of detecting a touch signal received through a plurality of touch signal lines connected to respective touch pads for transmitting a touch signal to determine whether or not a conductor is touched, Is performed by the touch detection section or the level shift detection section (14).

The touch pad further includes at least one separated signal line 300 having a predetermined constant width not connected to the touch pad between each row of the touch pad and between the touch signal line connected to the touch detection sensor of the corresponding row .

The isolation signal line is connected to the ground potential or the ground potential or a constant DC voltage.

In the touch detection step, a touch signal is sequentially detected in units of columns of the touch pad. At the time of touch signal detection, each column of the touch pad includes at least one sensing pad, And a plurality of non-sensing pads. The touch pad is divided into a plurality of non-sensing pads and a plurality of touch pads that are not simultaneously touched when the sensing pads are touched.

A non-sensing pad is connected to the ground or ground potential or a constant DC voltage.

When detecting a touch signal, the positions of the rows of the sensing pads and the non-sensing pads may be different for each column or may be the same for each column.

A plurality of sensing pads in each column, and at least one non-sensing pad is disposed between the sensing pads.

The n-sensing pad is characterized by being connected to a ground potential or a ground potential or to a constant DC voltage.

This is a method that can eliminate interference between signal lines more easily than a method for removing parasitic capacitance between signal lines by providing separate signal lines.

That is, by arranging the non-sensing pads between the sensing pads, the non-sensing pads can serve as separate separated signal lines.

Specifically, the non-sensing pad serves to separate the sensing pad, and the touch signal line connected to the non-sensing pad functions as a separate signal line for separating the touch signal line connected to the sensing pad.

Therefore, it is possible to obtain a desired effect of eliminating the interference between the signal lines without the drawback that the number of signal lines increases.

The sensing pads may be configured to be one for each column and the remainder may be non-sensing pads, and the non-sensing pads may be connected to a ground potential or a ground potential or a constant DC voltage.

In particular, the n-sensing pads are all connected so as to have the same potential.

Also, if the touch detection step is specifically described

A charging step of charging the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct generated by the appearance of the conductor existing in the touch pad by the charging means; An alternating voltage applying step of applying an alternating voltage to the touch pad by the alternate voltage applying unit and a voltage change of the touch detecting sensor at the time of occurrence of a touch and a voltage variation of the touch detecting sensor at the time of occurrence of touch by the level shift detecting unit And a level shift detecting step of determining whether or not a touch is made.

The charging means is turned off and the alternating voltage is applied while the parasitic capacitance Cp, the driving capacitance Cdrv and the touch capacitance Ct are maintained in a floating state, The input terminal of the detection unit maintains a high impedance (Hi-Z) state when it is judged whether or not it is touched.

Wherein a voltage variation in the touch detection sensor at the time of occurrence of a touch is smaller than a voltage variation at the touch detection sensor at the time of occurrence of the touch failure and a voltage variation in the touch detection sensor at the time of occurrence of a touch, Occurs in conjunction with the rising edge and the falling edge of the applied alternating voltage.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit and scope of the invention. It is.

10: touch pad 10a: sensing pad
10b: Non Sensing Pad 12: Charging means
14: touch detection unit or level shift detection unit 22: sensor signal line
22a: sensing pad sensor signal line 22b: non-sensing pad sensor signal line
25: finger 28: memory part
30: Touch Drive IC (TDI) 31: Multiplexer (Mux)
33: timing control section 35: signal processing section
40: CPU 42: Alternating voltage generating section
46: communication unit 47:
50: touch screen panel 57: adhesive member
58: air gap or contact member 200: display device
205: TFT substrate 210: liquid crystal layer
215: color filter 220: common electrode
230: Sealant

Claims (10)

A touch signal detecting apparatus for detecting a touch signal generated by an approach of a touch input means,
A touch pad disposed in rows and columns, the touch pad generating the touch signal;
A touch signal line connected to the touch pad; And
And a touch detection unit that receives the touch signal through the touch signal line and detects whether the touch input unit is touched,
The touch detection unit sequentially receives the touch signals of the touch pads of each column unit, and the touch pads of each column unit include at least one sensing pad during touch detection and a plurality of non-touch sensing pads However,
An alternating voltage is applied to the sensing pad when the touch signal is detected,
Wherein at least one non-sensing pad to which a zero potential or a ground potential or a constant DC voltage is applied is disposed between at least two sensing pads adjacent to each other in each column, Detection device. The method according to claim 1,
The nano-sensing pad serving as the separation signal line and the touch signal line connected to the nano-sensing pad are used to exclude mutual interference due to parasitic capacitance formed between the sensing pads and the touch signal lines connected to the sensing pads Wherein the touch signal detecting device comprises: The method according to claim 1,
Wherein a position of a row of at least one of the sensing pads when the touch signal is detected is different for each column. The method according to claim 1,
Wherein a position of a row of at least one of the sensing pads is the same for each column when the touch signal is detected. The method according to claim 1,
And the nano-sensing pads are connected so as to have the same potential. The method according to claim 1,
The touch signal detecting device
Charging means for charging the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct formed between the touch pad and the touch input tool, which are present in the touch pad;
An alternating voltage application unit for applying an alternating voltage to the sensing pad; And
And a level shift detector for comparing the voltage variation of the touch pad when the touch is not generated with the voltage variation of the touch pad when the touch is generated. The method according to claim 6,
The charging means is turned off so that the alternating voltage is applied in a state in which the parasitic capacitance Cp, the driving capacitance Cdrv, and the touch capacitance Ct are maintained in a floating state To be detected. 8. The method of claim 7,
Wherein the input terminal of the level shift detection unit maintains a high impedance (Hi-Z) state when it is determined that the touch is detected. The method according to claim 6,
Wherein the voltage level change in the touch pad when the touch is generated is smaller than the voltage level change in the case where no touch occurs. The method according to claim 6,
Wherein a voltage variation in the touch pad when the touch is generated and a voltage variation in the touch pad when the touch is not generated are generated in conjunction with a rising edge and a falling edge of the applied alternating voltage.

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