KR20140028219A - Touch detecting apparatus for improving visibility and method - Google Patents

Abstract

A touch detecting apparatus according to the present invention comprises: a plurality of sensor pads arranged in a matrix shape and made of a transparent material; a driving part including switches and driving capacitors electrically connected to the sensor pads and a plurality of selectable resistors connected between a charging signal and the driving capacitors, charging and floating the sensor pads using the switches, and then outputting voltage variations responding to an alternate voltage applied to the driving capacitors; and a plurality of signal wires connecting the sensor pads to the driving part, wherein the sensor pads have a plurality of spaces which are formed at the same intervals with those of the signal wires within the sensor pads. [Reference numerals] (AA) Forming a dummy pattern between sensor pads

Description

Touch detection device and touch detection method for improving visibility {TOUCH DETECTING APPARATUS FOR IMPROVING VISIBILITY AND METHOD}

The present invention relates to a touch detection device and a touch detection method, and more particularly, to a touch detection device and a touch detection method for improving visibility.

The touch screen panel is an input device for touching a user's hand or other contact means based on the contents displayed by the image display device so as to input a command of the user.

To this end, the touch screen panel is provided on the front face of the image display device and converts the contact position, which is in direct contact with a human hand or other contact means, into an electrical signal. Accordingly, the instruction content selected at the contact position is accepted as the input signal.

As a method of implementing a touch screen panel, a resistive film method, a light sensing method, and a capacitive method are known. Among them, the capacitive touch panel converts the contact position into an electrical signal by detecting a change in the capacitance formed by the conductive sensor pattern with other surrounding sensor patterns or the ground electrode when a human hand or an object is contacted.

1 is an exploded top view of an example of a conventional capacitive touch screen panel.

The conventional touch screen panel 1 includes a transparent substrate 2, a first sensor pattern 3 formed sequentially on the transparent substrate 2, a first insulating film 4, a second sensor pattern 5, 6 and a position detection line 7.

The first sensor pattern 3 is formed to be connected to one side of the transparent substrate 2 along the transverse direction. For example, the first sensor pattern 3 may be formed on the transparent substrate 2 in a regular pattern in which a plurality of diamond shapes are connected in a line.

The first sensor pattern 3 may be composed of a plurality of Y patterns formed so that the first sensor patterns 3 located on one row having the same Y coordinate are connected to each other. Lt; / RTI >

The second sensor patterns 5 are formed on the first insulating film 4 so as to be connected along the column direction and arranged alternately with the first sensor patterns 3 so as not to overlap with the first sensor patterns 3. For example, the second sensor pattern 5 may be formed in the same diamond pattern as the first sensor pattern 3, and the second sensor patterns 5 positioned in one column having the same X-coordinate are connected to each other. And the second sensor pattern 5 is connected to the position detection line 7 in units of columns.

The first and second sensor patterns 3 and 5 are made of a transparent conductive material such as indium tin oxide (ITO), and the first insulating layer 4 is made of a transparent insulating material.

Unit sensor patterns 3 and 5 are respectively electrically connected to the position detection line 7 to supply a contact position signal to a driving circuit (not shown) or the like.

When a hand or an object is brought into contact with the touch screen panel 1 shown in Fig. 1, the first and second sensor patterns 3 and 5 and the position detection line 7, Change is delivered. The contact position is recognized as a change in capacitance is converted into an electrical signal by an X and Y input processing circuit (not shown) or the like.

However, the conventional touch screen panel 1 must have an ITO pattern in each layer for X and Y, and an insulating layer must be provided between the X layer and the Y layer, thereby increasing the thickness. In addition, since the touch detection can be performed by accumulating the change of the capacitance which is generated finely by the touch several times, the capacitance change should be detected at the high frequency. This requires complex computation and statistical processing.

In addition, the difference between the electrical signals before and after the touch is extremely small, so it is influenced by the wiring resistance. Therefore, metal wiring is required to maintain a low resistance. An additional masking process is needed to form such metallization.

In addition, since the touch detection of the conventional touch screen panel 1 is highly dependent on the resistance value and is sensitive to noise, there is a great difficulty in increasing the touch detection sensitivity. In particular, a touch capacitance is not grounded at the time of touch, but a human body is affected by an antenna, and a noise signal of an environmental frequency component flows into the touch panel as an input. Actually, in an environment using a 50 Hz or 60 Hz home power source, an electric signal applied to a hand tip is interfered with an electric field generated from a home power source, and an input signal of the corresponding frequency is input to a touch sensing node. When a human body radiated noise signal flows into the touch panel, the touch detection value by the touch greatly changes, and it is impossible to distinguish whether or not the touch is detected.

Furthermore, the conventional touch screen panel 1 can not calculate an accurate touch area because a touch is detected by using a minute change of the capacitance accumulated several times by a complicated calculation. Thus, it was practically impossible for the user to use the touch area as one means of user input.

An object of the present invention is to provide an apparatus capable of detecting accurate touch coordinates.

In addition, another object of the present invention is to provide a touch detection device that can improve visibility. In more detail, a dummy pattern giving uniform characteristics between patterns is formed inside a sensor pad having a significant difference between patterns, thereby inducing visually uniform refractive index equalization, thereby improving visibility.

According to an aspect of the present invention, there is provided a touch sensing apparatus including: a plurality of sensor pads of a transparent material arranged in a matrix; A switch electrically connected to the plurality of sensor pads, the driving capacitor and a plurality of resistors connected between the charging signal and the driving capacitor and selectable resistors; and the driving capacitor after charging and floating the sensor pad using the switch. A driver for outputting a voltage change responsive to an alternating voltage applied thereto; A plurality of signal wires connecting the sensor pads to the driving unit, and a plurality of spaces are formed in the sensor pads, and the plurality of spaces are formed inside the sensor pads at the same intervals as the intervals between the signal wires. It is characterized by.

As described above, according to the touch detection apparatus according to the embodiment of the present invention, the touch detection speed can be increased, the influence of noise can be minimized, and the touch area and touch coordinates can be accurately detected.

In addition, by forming the same pattern and line width of the signal wirings connecting the sensor pads arranged in a matrix form with the driving device (touch IC), and the same pattern and line width inside the sensor pads, shape separation between the sensor pads and the signal wirings can be achieved. By minimizing the effect, the user may improve the phenomenon of seeing transparent conductive materials (eg, ITO, CNT, graphene, etc.) formed on the touch panel. That is, there is an effect that can improve the visibility of the touch panel.

1 is an exploded top view of a conventional touch screen panel.
2 is an exploded top view of a touch detection apparatus according to an embodiment of the present invention.
3 is a block diagram illustrating a configuration of a touch detection apparatus according to an embodiment of the present invention.
4 is a circuit diagram illustrating a touch detection unit according to an embodiment of the present invention.
5 is an exemplary waveform diagram of a touch detection unit according to an embodiment of the present invention.
6 is a schematic diagram showing a state in which a charging voltage is charged in a capacitor in a charging section of the waveform diagram shown in FIG.
7 is an exemplary view illustrating a touch panel according to an embodiment of the present invention.
8 is an exemplary view illustrating another touch panel in accordance with another embodiment of the present invention.
9 is an exemplary view illustrating a cross section of the touch panel illustrated in FIG. 7 or 8.

The terms used in this specification will be briefly described and the present invention will be described in detail.

While the present invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments. Also, in certain cases, there may be a term selected arbitrarily by the applicant, in which case the meaning thereof will be described in detail in the description of the corresponding invention. Therefore, the term used in the present invention should be defined based on the meaning of the term, not on the name of a simple term, but on the entire contents of the present invention.

When an element is referred to as "including" an element throughout the specification, it is to be understood that the element may include other elements, without departing from the spirit or scope of the present invention. In addition, the terms "... unit", "module", etc. described in the specification mean a unit for processing at least one function or operation, which may be implemented in hardware or software or a combination of hardware and software. . When a part is "connected" to another part, it includes not only a direct connection but also a connection with another system in the middle.

DETAILED DESCRIPTION Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein. In order to clearly illustrate the present invention, parts not related to the description are omitted, and similar parts are denoted by like reference characters throughout the specification.

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

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

First, a touch detection apparatus according to an embodiment of the present invention will be described in detail with reference to FIGS. 2 and 3. FIG.

FIG. 2 is an exploded top view of a touch detection apparatus according to an embodiment of the present invention, and FIG. 3 is a block diagram illustrating a configuration of a touch detection apparatus according to an embodiment of the present invention.

Referring to FIGS. 2 and 3, the touch detection apparatus according to the present embodiment includes a touch panel 100, a driving apparatus 200, and a circuit board 20 connecting the touch panel 100 and the touch panel 100.

The touch panel 100 includes a plurality of sensor pads 110 formed on a substrate 15 such as a transparent glass or plastic film and a plurality of signal lines 120 connected thereto.

The plurality of sensor pads 110 may be, for example, rectangular or rhombic, but are not limited thereto. The sensor pad 110 may be implemented as a uniform polygonal shape. The sensor pads 110 may be arranged in the form of a matrix of substantially contiguous polygons.

Each signal line 120 has one end connected to the sensor pad 110 and the other end extending to the lower edge of the substrate 15. The line width of the signal line 120 can be designed to be quite narrow to the order of several to several tens of micrometers.

The sensor pad 110 and the signal line 120 may be formed of a material such as indium tin oxide (ITO), antimony tin oxide (ATO), indium zinc oxide (IZO), carbon nanotube (CNT), graphene It can be made of a transparent conductive material.

The sensor pad 110 and the signal wiring 120 can be formed at the same time by, for example, laminating an ITO film on the substrate 15 by a method such as sputtering and then patterning using an etching method such as photolithography.

The sensor pad 110 and the signal wiring 120 may be covered with a transparent insulating film 10.

The driving device 200 for driving the touch panel 100 may be formed on a circuit board 20 such as a printed circuit board or a flexible circuit film but is not limited thereto and may be mounted directly on a part of the substrate 15 have. The driving apparatus 200 may include a touch detection unit 210, a touch information processing unit 220, a memory 230, and a control unit 240, and may be implemented by one or more integrated circuit (IC) chips.

The touch detection unit 210 is connected to the signal line 120 and receives signals from the control unit 240 to drive circuits for touch detection and outputs a voltage corresponding to a result of the touch detection determination. The touch detection unit 210 may include a plurality of switches connected to the sensor pad 110 and a capacitor.

The touch detection unit 210 may include an amplifier and an analog-to-digital converter, which converts, amplifies or digitizes the difference in voltage change of the sensor pad 110 and stores the same in the memory 230.

The touch information processor 220 processes the digital voltage stored in the memory 230 to generate necessary information such as whether or not it is touched, a touch area, and touch coordinates.

The control unit 240 controls the touch detection unit 210 and the touch information processing unit 220 and may include a micro control unit (MCU), and may perform predetermined signal processing through the firmware.

The memory 240 stores a predetermined voltage or real-time data to be used for the touch detection, the area calculation, the touch calculation, and the digital voltage based on the difference of the voltage change detected from the touch detection unit 210.

As described above, the touch detection unit 210, the touch information processing unit 220, the memory 230, and the control unit 240 may be separated, or two or more components may be integrated.

4 to 6, a specific embodiment of the touch panel and the touch detection unit and its operation will be described in detail.

FIG. 4 is a circuit diagram illustrating a touch detection unit according to an embodiment of the present invention, FIG. 5 is an exemplary waveform diagram of a touch detection unit according to an embodiment of the present invention, FIG. 6 is a waveform diagram of FIG. FIG. 3 is a schematic view showing a state in which a charging voltage is charged in a capacitor in a charging section. FIG.

4, the touch detection unit 210 includes a plurality of selectable resistors R1 through Rn, a plurality of transistors 211 performing a switching operation, a plurality of parasitic capacitors Cp, a plurality of drive capacitors Cdrv, A plurality of common capacitors Cvcom and a plurality of level shift detectors 212 and are connected to the sensor pads 110 through signal lines 120. [ The transistor 211, the parasitic capacitor Cp, the drive capacitor Cdrv, the common capacitor Cvcom and the level shift detection unit 212 can be grouped one by one per sensor pad 110 and signal line 120, The sensor pad 110, the signal wiring 120, the transistor 211, the parasitic capacitor Cp, the driving capacitor Cdrv, and the common capacitor Cvcom are collectively referred to as a "touch cell ". The touch cell is a concept that includes the case where each component is electrically connected by a multiplexer. For the sake of simplicity, the capacitors and their capacitances shall have the same reference numerals.

The transistor 211 is, for example, a field effect transistor, and a control signal Vg may be applied to the gate, a charge signal Vb may be applied to the source (or drain) 120, respectively. The control signal Vg and the charge signal Vb may be applied under the control of the control unit 240. [ Here, other elements capable of switching in place of the transistor 211 may be used.

One of the resistors (R1 to Rn) is selected and connected between the charging signal (Vb) and the transistor (211).

The parasitic capacitance Cp means a capacitance attached to the sensor pad 110 and is a kind of parasitic capacitance formed by the sensor pad 110, the signal wiring 120, and the like. The parasitic capacitance Cp may include any parasitic capacitance generated by the touch detection unit 210, the touch panel, and the image display device.

The common capacitance Cvcom is a capacitance formed between the common electrode (not shown) of the display device and the touch panel 100 when the touch panel 100 is mounted on a display device (not shown). A common voltage Vcom such as a square wave is applied to the common electrode by the display device. On the other hand, the common capacitance Cvcom can be included in the parasitic capacitance Cp as a kind of parasitic capacitance, and the common capacitance Cvcom will be included in the parasitic capacitance Cp unless otherwise noted.

The driving capacitance Cdrv is a capacitance formed in a path for supplying an alternating voltage Vdrv alternating at a predetermined frequency for each sensor pad 110. [ The alternating voltage Vdrv applied to the driving capacitor Cdrv is preferably a square wave signal. The alternating voltage Vdrv may be a clock signal having the same duty ratio but may have a different duty ratio. The alternating voltage Vdrv may be provided by a separate alternating voltage generating means, but the common voltage Vcom may also be used.

4, the touch capacitance Ct indicates capacitance formed between the sensor pad 110 and a touch input tool such as a user's finger when the user touches the sensor pad 110. [

In the future, it is possible to arrange a cell having an electrical characteristic that is placed in a position that can not be touched by the user, or is not always touched. The "reference cell" may be physically present, but may be a virtual cell having only data values.

5, the controller 240 may apply the charge signal Vb and the control signal Vg to the source and gate of the transistor 211, respectively.

First, a case where the touch input tool is not touched to the sensor pad 110 (non-touch) will be described. When the charging period T1 starts after the charging signal Vb rises to, for example, 10 V and the control signal Vg applied to the gate of the transistor 211 rises from the low voltage VL to the high voltage VH, (211) is turned on. Accordingly, the sensor pad 110 starts to be charged by the charge signal Vb, and the charge is also charged to the parasitic capacitor Cp, the drive capacitor Cdrv, and the common capacitor Cvcom by the charge voltage Vb. When the charge charged in the sensor pad 110 reaches the target voltage Vpc, the control unit 240 lowers the control signal Vg from the high voltage VH to the low voltage VL to turn off the transistor 211, And completes the section T1. The touch detection unit 210 may include a comparator (not shown) so that the target voltage Vpc and the output voltage Vo may be input to the comparator and the output thereof may be used as the control signal Vg.

Referring to FIG. 6, when the charging period T1 starts and the transistor 211 is turned on, it is equal to the voltage V = Vb * e- ^{t / (R * C)} charged in the entire capacitor C. Here, R is a resistance value selected from a plurality of resistors R1 to R4, and C is a sum of capacitances of the parasitic capacitor Cp, the driving capacitor Cdrv, and the common capacitor Cvcom. If the charging voltage Vb is sufficiently higher than the target voltage Vpc, the time required to reach the target voltage Vpc can be shortened by the above equation.

For example, when the target voltage Vpc is 5 V, the time when the charging voltage Vb is 5 V (V1) and the charging voltage Vb is 10 V (V2) To about half the level. Accordingly, the touch detection speed can be increased. Also, the waveform of the voltage V charged in the capacitor C may vary as in V3 depending on the resistance value selected from the plurality of resistors R1 to Rn.

Therefore, when a malfunction occurs in a specific frequency band at the time of touch detection, it is possible to select a resistor among the plurality of resistors R1 to Rn to enable the malfunction band avoidance start-up. Not only the resistors V1 to Vn but also the target voltage Vpc and the charging voltage Vb can be varied as needed so that the charge charging speed and the amount of current can be controlled. When the charging voltage Vb is sufficiently high, the relative strong current can be detected by raising the target voltage Vpc. When the strong current detection condition is established as described above, since the charging potential of the capacitor C is high during touch detection, Which is strong against the radiated noise in the self-pressing state.

Next, when the sensing period T2 starts with the control signal Vg falling from the high voltage VH to the low voltage VL, the transistor 211 is turned off, and the touch capacitor Ct, the parasitic capacitor Cp, The capacitor Cdrv and the common capacitor Cvcom are isolated in a charged state. In order to stably isolate the charged signal, the input terminal of the level shift detection unit 212 preferably has a high impedance. However, when discharging the charged signal to the sensor pad 110 and the driving capacitor Cdrv, The impedance of the input terminal of the level shift detection unit 212 may be low if the charge signal is isolated by observation or other means or if it is possible to quickly observe the discharge start point.

A state in which the charge charged in the sensor pad 110 is isolated is referred to as a floating state. At this time, when the alternating voltage Vdrv applied to the drive capacitor Cdrv increases from 0 V to 5 V, for example, the voltage level of the output voltage Vo of the sensor pad 110 instantaneously rises, The level of the output voltage Vo drops instantaneously. This phenomenon of rising or falling voltage levels is sometimes called "kick-back".

When there is no touch on the sensor pad 110, that is, when the capacitors connected to the sensor pad 110 are only the driving capacitors Cdrv and the parasitic capacitors Cp, the output voltage Vo by these capacitors Cdrv, The voltage variation?

[Equation 1]

. Here, VdrvH and VdrvL are the high level voltage and the low level voltage of the alternating voltage Vdrv, respectively.

Next, a case where the touch input tool is touched on the sensor pad 110 will be described. The touch capacitors Ct are formed between the sensor pad 110 and the touch input tool so that the capacitors connected to the sensor pad 110 are connected to the touch capacitors Cdrv and Cp in addition to the capacitors Cdrv and Cp. Ct) is added. The charging voltage Vb is charged in the charging period T3 and the voltage fluctuation? Vo of the sensor pad 110 by the three capacitors Cdrv, Cp, and Ct during the sensing period T4 ) Is expressed by the following equation (2).

&Quot; (2) "

Comparing the equations (1) and (2), the touch capacitance Ct is added to the numerator item of the equation (2), so that the voltage variation? Quot; is smaller than the voltage variation [Delta] Vo in the absence of the touch capacitance Ct, and the difference is dependent on the touch capacitance Ct. The difference in voltage fluctuation? Vo before and after the touch is referred to as "level shift ".

In general, the capacitance C of the capacitor is proportional to the area A of the electrode and is proportional to the distance d between the electrodes, that is, C = εA / d (ε is the dielectric constant). Therefore, as the touch area increases, the touch capacitance Ct increases. 5, when the alternating voltage Vdrv applied to the driving capacitor Cdrv fluctuates in the sensing periods T2 and T4 during which the transistor 211 is turned off, A voltage change occurs. By using such a relationship, it is possible to calculate the touch area and the touch area using the difference in the voltage variation (? Vo) of the output voltage Vo before and after the touch.

Referring again to FIG. 4, the level shift detecting section 212 detects a level shift caused by the alternating voltage Vdrv in the floating state. Specifically, the level shift detection unit 212 detects a variation (? Vo) of the output voltage (Vo) at the sensor pad 110 at the time of occurrence of a non-touch and a variation (? V0) of the output voltage Vo at the sensor pad ? Vo) can be measured to detect whether a level shift has occurred. That is, the potential of the sensor pad 110 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 212 detects the level shift by comparing the output voltage Vo levels before and after the touch. Further, the level shift detection unit 212 can acquire the touch signal based on the difference of the voltage variation.

7 is an exemplary view illustrating a touch panel according to an embodiment of the present invention.

Before describing FIG. 7, first, referring to FIG. 3, the touch panel 100 of FIG. 3 includes a single layer including a plurality of sensor pads 110 and a plurality of signal wires 120 in a matrix form formed on a substrate surface. Touch panel having a transparent conductive material (eg, ITO, CNT, graphene, etc.).

Since the signal wire 120 has a relatively small line width, pitch, and density compared to the sensor pad 110, there has been a problem of visual interference.

In order to solve this problem, researches for implementing optimized ITO deposition having high transmissive properties have been conducted, and techniques for introducing an oxide underlayer as an index matching concept between an underlying substrate and an ITO material have been developed.

However, in the case of FIG. 3, when the significant difference between signal wires is obvious, visibility has not been completely overcome.

The touch panel of FIG. 7 is designed to solve the above-described problem, and by forming a space that gives uniformity between patterns in the sensor pad 110 with respect to a signal wiring of a distinct type between patterns, When the user looks at the touch panel with the naked eye, the user tries to induce visually uniform refractive index equalization (Averaging) to improve visibility.

That is, the sensor pads 110 having the same pitch and line width as those of the signal wiring 120 are regularly formed in each sensor pad 110, which is a transparent electrode pattern, and the sensor pad 110 does not pass through the signal wiring 120. ) And a dummy pattern is formed in the empty space between the sensor pad 110 and the same pitch and line width as the signal wire 120. In this case, the dummy pattern may be formed of the same transparent conductive material (ITO, CNT, graphene, etc.) as the sensor pad 110 or the signal wire 120, and the same pitch and line width as the signal wire 120 as in the above-described space. It may be formed to have.

Meanwhile, as illustrated in FIG. 7, the sensor pad 110 connects the outer surface of the sensor pad 110, the pattern line formed inside the sensor pad 110, and the sensor pad 110 and the driver 200. The signal wire 120 may be implemented in the form of a wave line. That is, the sensor pad having a rectangular edge shown in FIG. 3 is implemented by changing the wave pad shape together with the signal wire. Through this, it is possible to further improve visibility by promoting visually uniform refractive index equalization.

8 is an exemplary view illustrating another touch panel in accordance with another embodiment of the present invention.

Referring to FIG. 8, the conductive patterns formed in the sensor pad 110 are arranged in the form of independent squares instead of the continuous connection structure in the longitudinal direction like the signal wires 120. For example, circular, rectangular, triangular, Concept includes at least one polygonal shape, such as a pentagon.

FIG. 9 is an exemplary view illustrating a cross-section B-B 'of the touch panel illustrated in FIG. 7 or a cross-section C-C' illustrated in FIG. 8, and the transmission and reflectance of light may be determined by the following equation.

Index of Reflection in any medium: n _r Quot;

The transmittance of the light,

&Quot; (3) "

The reflectance (R) of the light is

&Quot; (4) "

Insertion of a dummy pattern (or formation of a space) in the sensor pad 110 increases the aperture ratio, which gives more possibility of light transmission, thereby giving uniformity with the signal wiring 120, thereby causing a difference between the reflective index between the substrate and the substrate-ITO. It is expected that not only can improve the visibility through the uniform refractive index with respect to, but also improve the light transmittance of the display screen mounted on the touch panel.

10: insulating film, 15: substrate,
20: circuit board, 100: touch panel,
110: sensor pad, 120: signal wiring,
200: drive unit, 210: touch detection unit,
212: transistor, 212: level shift detector,
221: touch cell detector, 222: touch area calculator,
223: touch coordinate calculator, 230: memory,
240:

Claims (1)

A plurality of sensor pads of transparent material arranged in a matrix form;
A switch electrically connected to the plurality of sensor pads and a driving capacitor and a plurality of resistors connected between the charging signal and the driving capacitor, the plurality of selectable resistors being used; A driver for outputting a voltage change responsive to an alternating voltage applied thereto;
A plurality of signal wires connecting the sensor pads to the driving unit;
A plurality of spaces are formed in the sensor pad, and the plurality of spaces are formed inside the sensor pad to have the same pitch and line width as the signal wiring.
Touch detection device.

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