CN203376724U - Capacitive touch screen - Google Patents

Abstract

The utility model provides a capacitive touch screen which comprises a transparent protective cover plate, a plurality of induction electrodes and a touch-control chip, wherein the induction electrodes are arranged on the surface of the transparent protective cover plate and arranged in a two-dimensional array; the touch-control chip is bound and fixed to the surface of the transparent protective cover plate, and the induction electrodes are respectively connected with the touch-control chip through wires. According to the capacitive touch screen, the problem of errors caused by noise transmission between the electrodes in the prior art is solved on the premise of achieving multi-point touch control, and signal noise ratios are remarkably enhanced.

Description

Capacitive touch screen

Technical field

The utility model relates to the touch technology field, relates in particular to a kind of capacitive touch screen.

Background technology

Current, capacitive touch screen is widely used in various electronic products, has been penetrated into gradually the every field of people's work and life.The size of capacitive touch screen day by day increases, and from 3 inches to 6.1 inches of smart mobile phone, to 10 inches left and right of panel computer, the application of capacitive touch screen more extends to intelligent television etc.But the problems such as existing capacitive touch screen ubiquity interference free performance is poor, the scanning frame per second is low, volume is large and manufacturing process is complicated.

The utility model content

In view of this, the utility model embodiment provides a kind of capacitive touch screen, at least one among can overcoming the above problems.

The capacitive touch screen that the utility model embodiment provides comprises:

Transparency protected cover plate;

Be arranged at a plurality of induction electrodes on described transparency protected cover plate surface, described a plurality of induction electrodes are arranged in two-dimensional array;

Be tied to the touch control chip on described transparency protected cover plate surface, described touch control chip is connected by wire respectively with each induction electrode among described a plurality of induction electrodes.

Preferably, also comprise: with the flexible circuit board that described touch control chip is connected, described touch control chip and described flexible circuit board are tied to described transparency protected cover plate surface by anisotropic conductive film (ACF).

Preferably, described transparency protected cover plate is provided with viewing area.

Preferably, described capacitive touch screen also comprises light shield layer, and described light shield layer is arranged at outside described transparency protected cover plate viewing area.

Preferably; described a plurality of induction electrode is arranged at described transparency protected cover plate lower surface; described touch control chip and described flexible circuit board are arranged at outside described transparency protected cover plate lower surface viewing area; described light shield layer is arranged at described transparency protected cover plate lower surface, and is positioned at the top of described touch control chip and described flexible circuit board.

Preferably, described capacitive touch screen also comprises the transparent membrane that is covered in described transparency protected cover plate upper surface.

Preferably; described a plurality of induction electrode is arranged at described transparency protected cover plate lower surface; described touch control chip and described flexible circuit board are arranged at outside described transparency protected cover plate lower surface viewing area, and described light shield layer is arranged at the lower surface of described transparent membrane.

Preferably, described transparent membrane is fitted by full wafer optical cement and described transparency protected cover plate, or described transparent membrane is fitted by mouth word glue and described transparency protected cover plate.

Preferably, described touch control chip configuration is for detecting the self-capacitance of each induction electrode.

Preferably, described touch control chip configuration is for detecting by the following method the self-capacitance of each induction electrode:

With voltage source or the described induction electrode of driven with current sources; And

Detect voltage or frequency or the electric weight of described induction electrode.

Preferably, described touch control chip configuration is for detecting by the following method the self-capacitance of each induction electrode:

Drive and detect described induction electrode, drive all the other induction electrodes simultaneously; Perhaps

Drive and detect described induction electrode, drive the induction electrode of described induction electrode periphery simultaneously;

Wherein, driving the signal of described induction electrode and driving the signal of the induction electrode of described all the other induction electrodes and described induction electrode periphery is identical voltage or current signal, or different voltage or current signal.

Preferably, described touch control chip configuration is for detecting by the following method the self-capacitance of each induction electrode:

Detect all induction electrodes simultaneously; Perhaps

Grouping detects each induction electrode.

Preferably, described touch control chip configuration is for to determine touch location according to two-dimentional capacitance variations array.

Preferably, described capacitive touch screen comprises a plurality of touch control chips that are tied on described transparency protected cover plate, and each touch control chip is for detection of the corresponding a part of induction electrode among described a plurality of induction electrodes.

According to the capacitive touch screen of the utility model embodiment, adopt a plurality of induction electrodes that are arranged in two-dimensional array, solved under realizing the prerequisite of multi-point touch in the prior art and transmitted the error caused because of noise between electrode, significantly improved signal to noise ratio (S/N ratio).Utilize the scheme of the utility model embodiment, greatly eliminated the power supply noise of touch-screen, also can weaken radio frequency (RF) and from the interference of other noise sources such as liquid crystal display module.

Capacitive touch screen according to the utility model embodiment; the touch control chip is connected by wire respectively with each induction electrode; and be tied on transparency protected cover plate in the COG mode, can avoid the many difficulties that may cause of number of pin, can also reduce whole volume.In addition, by while or grouping, detect each induction electrode, can significantly reduce sweep time, thereby avoid the many problems that may cause of induction electrode quantity.

The accompanying drawing explanation

Fig. 1 is the vertical view of the capacitive touch screen that provides of the utility model embodiment mono-;

Fig. 2 is the vertical view of the related induction electrode array of the utility model embodiment mono-;

Fig. 3 is the deck structure schematic diagram of the capacitive touch screen that provides of the utility model embodiment bis-;

Fig. 4 is the deck structure schematic diagram of the capacitive touch screen that provides of the utility model embodiment tri-;

Fig. 5 to Fig. 8 shows the induction electrode driving method according to the utility model embodiment;

Fig. 9 A-9D shows four application scenarioss according to the capacitive touch screen of the utility model embodiment;

Figure 10 shows the signal flow diagram according to the touch control chip of the utility model embodiment;

Figure 11 A shows an example of the coordinate that adopts the centroid algorithm calculated touch location;

Figure 11 B shows the coordinate that adopts the centroid algorithm calculated touch location in noisy situation.

Embodiment

For the purpose of this utility model, feature and advantage can more be become apparent, below in conjunction with the accompanying drawing in the utility model embodiment, the technical scheme of utility model being opened to embodiment is described.Obviously, described embodiment is only a part of embodiment of the present utility model.Based on the utility model embodiment, any other embodiment that those skilled in the art obtain under the prerequisite of not paying creative work, should belong to protection domain of the present utility model.For ease of explanation, mean that the sectional view of structure is disobeyed general ratio and done local the amplification.And accompanying drawing is exemplary, it should not limit protection domain of the present utility model.The three-dimensional dimension that in actual fabrication, should comprise in addition, length, width and the degree of depth.

Embodiment mono-

The utility model embodiment provides a kind of capacitive touch screen, the vertical view that Fig. 1 is this capacitive touch screen, and this capacitive touch screen comprises: transparency protected cover plate (Cover Lens) 11; A plurality of induction electrode 12(Fig. 1 that are arranged at described transparency protected cover plate surface do not show), described a plurality of induction electrodes 12 are arranged in two-dimensional array; Be tied to the touch control chip 13 on described transparency protected cover plate surface, described touch control chip 13 is connected by wire respectively with each induction electrode among described a plurality of induction electrodes 12.

Transparency protected cover plate 11 can be clear glass.Be provided with a plurality of induction electrodes 12 on cover sheet 11, described a plurality of induction electrodes 12 form two-dimensional array, can be the two-dimensional arraies of rectangular array or other analogous shapes.For capacitive touch screen, each induction electrode 12 is capacitive transducers, and the electric capacity of capacitive transducer changes while being touched in the touch-screen relevant position.

Each induction electrode 12 is wired to touch control chip 13, and touch control chip 13 is bundled on transparency protected cover plate.Owing to being connected by wire respectively with each induction electrode 12, the pin of touch control chip 13 is very many, therefore, touch control chip 13 is bundled on transparency protected cover plate to the difficulty that can avoid conventional encapsulation.Particularly, touch control chip 13 can be tied on transparency protected cover plate 11 by glass flip chip (Chip-on-Glass, COG) mode.According to the utility model embodiment, can there is anisotropic conductive film (ACF) between touch control chip 13 and transparency protected cover plate 11.

In addition, by conventional flexible circuit board (FPC) to induction electrode and control to touch that chip is connected need to be to touch control chip and FPC headspace on hardware, be unfavorable for that system simplifies.And, by the COG mode, touch control chip and touch-screen become one, thereby have reduced the volume of whole touch-screen.

Because induction electrode 12 is general by transparency protected cover plate, tin indium oxide (ITO) being carried out to etching formation; and touch control chip 13 also is positioned on transparency protected cover plate; therefore, wire between the two can complete by an ITO etching, has significantly simplified manufacturing process.

Fig. 2 is the vertical view of the related induction electrode array of the utility model embodiment.It will be understood by those skilled in the art that shown in Fig. 2 to be only a kind of arrangement mode of induction electrode, in concrete enforcement, induction electrode can be arranged in any two-dimensional array.For capacitive touch screen, each induction electrode is a capacitive transducer, and the electric capacity of capacitive transducer changes when on touch-screen, relevant position is touched.In addition, the spacing of each induction electrode on either direction can equate, can be also not wait.Those skilled in the art also should be understood that the quantity of induction electrode can be more than the quantity shown in Fig. 2.

It will be understood by those skilled in the art that to be only a kind of shape of induction electrode shown in Fig. 2.According to other embodiment, the shape of induction electrode can be rectangle, rhombus, circle or oval, can be also irregularly shaped.The pattern of each induction electrode can be consistent, can be also inconsistent.For example, the induction electrode at middle part adopts diamond structure, the employing triangular structure at edge.In addition, the size of each induction electrode can be consistent, can be also inconsistent.For example, larger by inner induction electrode size, the size of the edge that keeps to the side is less, so is conducive to the touch precision at cabling and edge.

Each induction electrode has wire to draw, and wire is distributed in the space between induction electrode.Generally speaking, wire is as far as possible even, and cabling is as far as possible short.In addition, the cabling scope of wire guarantee safe distance as far as possible narrow under prerequisite, thereby leave the more area of induction electrode for, make induction more accurate.

Each induction electrode can be connected to bus 22 by wire, and bus 22 by wire directly or with the pin of touch control chip, be connected after certain sequence.For the touch-screen of giant-screen, the quantity of induction electrode may be very many.In this case, can be with all induction electrodes of single touch control chip controls; Also can control respectively the induction electrode of zones of different with a plurality of touch control chips by screen partition, between a plurality of touch control chips, can carry out clock synchronous.Now, bus 22 may be partitioned into several bus collection, in order to be connected from different touch control chips.The induction electrode of each touch control chip controls equal number, or the induction electrode of control varying number.

The touch of induction electrode array shown in Fig. 2 based on self-capacitance detects principle.Ad-hoc location on the corresponding screen of each induction electrode, in Fig. 2,2a-2d means different induction electrodes.21 mean a touch, and when touch occurs in certain corresponding position of induction electrode, the electric charge on this induction electrode changes, and therefore, detects the electric charge (current/voltage) on this induction electrode, can know whether this induction electrode touch event occurs.Generally speaking, this can be converted to digital quantity to analog quantity by analog to digital converter (ADC) and realizes.The electric charge change amount of the induction electrode area capped with induction electrode is relevant, and for example, in Fig. 2, the electric charge change amount of induction electrode 2b and 2d is greater than the electric charge change amount of induction electrode 2a and 2c.

All there is corresponding induction electrode each position on screen, and there is no physical connection between induction electrode, therefore, the capacitive touch screen that the utility model embodiment provides can be realized real multi-point touch, avoids self-capacitance in prior art to touch the ghost point problem detected.

Embodiment bis-

Fig. 3 is the side structure schematic diagram of the capacitive touch screen that provides of the utility model embodiment bis-.With embodiment mono-, compare, the disclosed capacitive touch screen of the present embodiment also comprises light shield layer 14, and transparency protected cover plate 11 is provided with viewing area, and light shield layer is arranged at outside transparency protected cover plate 11 viewing areas.As shown in Figure 3, a plurality of induction electrodes 12 are arranged at the lower surface of transparency protected cover plate 11, and the plurality of induction electrode 12 is arranged in two-dimensional array; Touch control chip 13 is arranged at outside transparency protected cover plate 11 lower surface viewing areas; Touch control chip 13 is connected by wire respectively with each induction electrode among a plurality of induction electrodes 12.

In the present embodiment, light shield layer 14 can or can be comprised of with the light screening material of transparency protected cover plate 11 effective combinations versicolor printing ink.

In addition, light shield layer 14 belows also can be provided for connecting the flexible circuit board 15 of described touch control chip 13 and external host.Wherein, described flexible circuit board 15 can be led to the lower surface that anisotropic conductive film (ACF) is bundled in transparency protected cover plate 11.

In the present embodiment, the wire that is arranged at viewing area need adopt light transmission material preferably, comprise transparent material (such as ITO etc.) and on the light transmission impact less material (such as the nano-silver thread of live width 5um etc.), be conducive to improve the light penetration of viewing area.Be arranged at the wire in zone outside viewing area, can select the less material of impedance, do not need to consider light transmission.

Due to the setting of induction electrode in the present embodiment 12, touch control chip 13, and the connection between induction electrode 12 and touch control chip 13 all can adopt the mode in embodiment mono-to carry out, and therefore, at this, do not do and repeats.

Embodiment tri-

Fig. 4 is the side structure schematic diagram of the capacitive touch screen that provides of the utility model embodiment tri-.With embodiment bis-differences, be, in the present embodiment, the outer surface of transparency protected cover plate 11 increases layer of transparent film 16, and light shield layer 14 is arranged at the lower surface of transparent membrane 16.As shown in Figure 4, a plurality of induction electrodes 12 are arranged on the lower surface of transparency protected cover plate 11, and the plurality of induction electrode 12 is arranged in two-dimensional array; Touch control chip 13 is arranged at outside the viewing area of transparency protected cover plate 11 lower surfaces; Touch control chip 13 is connected by wire respectively with each induction electrode among a plurality of induction electrodes 12; Transparent membrane 16 is covered in the upper surface of transparency protected cover plate 11; And between transparent membrane 16 and transparency protected cover plate 11, light shield layer 14 is set, and light shield layer 14 present positions are positioned at outside the viewing area of transparency protected cover plate 11.

In the present embodiment, transparent membrane 16 can be high-temperature polyester (PET) film, polycarbonate (PC) film or polymethylmethacrylate (PMMA) film etc.; Light shield layer 14 can or can be comprised of with the light screening material of the effective combination of transparent membrane versicolor printing ink.

With embodiment bis-, compare, the technical scheme that the present embodiment adopts is the upper surface increase layer of transparent film 16 at transparency protected cover plate 11, and light shield layer 14 is arranged at the lower surface of transparent membrane 16.More complicated owing on the transparency protected cover plate 11 of glass material, light shield layer technique being set, cost of manufacture is higher, and transparent membrane is as relatively cheap as the PET film, and it is simple that light shield layer technique is set on its surface, thereby can effectively reduce cost of manufacture.

In addition, also can below light shield layer 14, be provided for connecting the flexible circuit board 15 of touch control chip 13 and external host.Wherein, flexible circuit board 15 can be bundled in transparency protected cover plate 11 lower surfaces by anisotropic conductive film (ACF).

In the present embodiment, the wire that is arranged at viewing area need adopt light transmission material preferably, comprise transparent material (such as ITO etc.) and on the light transmission impact less material (such as the nano-silver thread of live width 5um etc.), be conducive to improve the light penetration of viewing area.Be arranged at the wire in zone outside viewing area, can select the less material of impedance, do not need to consider light transmission.

Transparent membrane is fitted by full wafer optical cement and transparency protected cover plate, or transparent membrane is fitted by mouth word glue and transparency protected cover plate.

Due to the setting of induction electrode in the present embodiment 12, touch control chip 13, and the connection between induction electrode 12 and touch control chip 13 all can adopt the mode in embodiment mono-to carry out, and therefore, at this, do not do and repeats.

The structure of the capacitive touch screen provided based on above-described embodiment, Fig. 5 to Fig. 9 D shows the induction electrode driving method according to the utility model embodiment.As shown in Figure 5, induction electrode 12 is driven by drive source 24, and drive source 24 can be voltage source or current source.For different induction electrode 12, drive source 24 not necessarily adopts identical structure.For example, can partly adopt voltage source, part adopts current source.In addition, for different induction electrode 12, the frequency of drive source 24 can be identical, also can be different.Sequential control circuit 23 is controlled the sequential of each drive source 24 work.

The driving sequential of each induction electrode 12 has multiple choices.As shown in Figure 6A, all induction electrodes drive simultaneously, detect simultaneously.This mode completes the needed shortest time of single pass, and drive source quantity is (consistent with the quantity of induction electrode) at most.As shown in Figure 6B, the drive source of induction electrode is divided into some groups, and every group drives the electrode in specific region successively.This mode can realize that drive source is multiplexing, but can increase sweep time, but by selecting suitable number of packet, can make drive source multiplexing and reach compromise sweep time.

Fig. 6 C shows conventional mutual capacitance and touches the scan mode detected, and supposes to have N to drive passage (TX), and be Ts the sweep time of each TX, and the time of having scanned a frame is N*Ts.And adopt the induction electrode driving method of the present embodiment, and all induction electrodes can be detected together, the time of having scanned a frame is Ts the most only.That is to say, touch to detect with conventional mutual capacitance and compare, the scheme of the present embodiment can improve sweep frequency N doubly.

For the mutual capacitance touchscreens that 40 driving passages are arranged, if each drives the sweep time of passage, be 500us, be 20ms the sweep time of whole touch-screen (frame), frame per second is 50Hz.50Hz often can not reach the requirement of good experience.The scheme of the utility model embodiment can address this problem.Be arranged in the induction electrode of two-dimensional array by employing, all electrodes can detect simultaneously, in the situation that keep 500us the detection time of each electrode, frame per second reaches 2000Hz.This is well beyond the application requirements of most touch-screens.Additional scan-data can be utilized by the digital signal processing end, for for example anti-interference or optimization touch track, thereby obtains better effect.

Preferably, detect the self-capacitance of each induction electrode.The self-capacitance of induction electrode can be its ground capacitance.

As an example, can adopt the charge detection method.As shown in Figure 7, drive source 41 provides constant voltage V1.Voltage V1 can be malleation, negative pressure or ground.S1 and S2 mean two controlled switchs, and 42 mean the ground capacitance of induction electrode, and 45 mean the electric charge receiver module, and electric charge receiver module 45 can be clamped to input terminal voltage designated value V2, and measures the quantity of electric charge inputed or outputed.At first, the closed S2 of S1 disconnects, and the top crown of Cx is charged to the voltage V1 that drive source 41 provides; Then S1 disconnects the S2 closure, and charge exchange occurs for Cx and electric charge receiver module 45.If charge transfer quantity is Q1, the top crown voltage of Cx becomes V2, by C=Q/ Δ V, Cx=Q1/ (V2-V1) is arranged, thereby realized capacitance detecting.

As another example, also can adopt current source, or obtain its self-capacitance by the frequency of induction electrode.

Alternatively, in the situation that use a plurality of drive sources, when detecting an induction electrode, for adjacent with this induction electrode or induction electrode periphery, can select to be different from the voltage of the drive source of this tested electrode.For succinct purpose, Fig. 8 only shows three induction electrodes: tested electrode 57 and two adjacent electrodes 56 and 58.It will be understood by those skilled in the art that following example also is applicable to the situation of more induction electrodes.

The drive source 54 be connected with tested electrode 57 is connected to voltage source 51 by switch S 2, to realize the driving to tested electrode 57; And the induction electrode 56 adjacent with tested electrode 57 is connected with 55 with drive source 53 with 58, they can for example be connected to voltage source 51 or specific reference voltage 52(by switch S 1 and S3).If switch S 1 and S3 are connected to voltage source 51, drive the electrode of tested electrode and periphery thereof with same voltage source simultaneously, can reduce like this voltage difference of tested electrode and its peripheral electrode, be conducive to reduce the electric capacity of tested electrode and be conducive to take precautions against the falseness touch that water droplet forms.

Preferably, the touch control chip configuration is for adjust sensitivity or the dynamic range touch detected by the parameter of drive source, and described parameter comprises any or the combination among amplitude, frequency and sequential.As an example, as shown in Figure 8, the sequential of the parameter of drive source (for example, driving voltage, electric current and frequency) and each drive source can be controlled by the steering logic 50 of the signal drive circuit in the touch control chip.By these parameters, can adjust different circuit working states, for example high sensitivity, moderate sensitivity degree or muting sensitivity, or different dynamic ranges.

Different circuit working states is applicable to different application scenarioss.Fig. 9 A-9D shows four application scenarioss according to the capacitive touch screen of the utility model embodiment: the finger normal touch, and finger suspension touch-control, active/passive pen or tiny conductor, and the band gloves touch.In conjunction with above-mentioned parameter, can realize the detection to one or more normal touch and one or more tiny conductor touches.Although it will be understood by those skilled in the art that the signal receiving unit 59 shown in Fig. 8 separates with signal drive circuit 50, in other embodiments, they can be realized by same circuit.

Figure 10 shows the signal flow diagram according to the touch control chip of the utility model embodiment.Have on induction electrode and touch while occurring, the electric capacity of induction electrode can change, and this change amount converts digital quantity to by ADC, just can recover touch information.Generally speaking, electric capacity change amount and this induction electrode area that thing hides that is touched is relevant.Signal receiving unit 59 receives the sensed data of induction electrode, through signal processing unit, recovers touch information.

As an example, the following specifically describes the data processing method of signal processing unit.

Step 61: obtain sensed data.

Step 62: sensed data is carried out to filtering and noise reduction.The purpose of this step is the noise of as far as possible eliminating in original image, in order to subsequent calculations.This step specifically can adopt spatial domain, time domain or thresholding filtering way.

Step 63: find wherein possible touch area.These zones comprise real touch area and invalid signals.Invalid signals comprises large tracts of land touch signal, power supply noise signal, unsettled abnormal signal and water droplet signal etc.What these invalid signals had approaches with actual touch, and actual touch is disturbed in some meetings, and what have should not be resolved into normal touch.

Step 64: abnormality processing, to eliminate above-mentioned invalid signals and to obtain reasonable Petting Area.

Step 65: calculated according to the data of reasonable Petting Area, to obtain the coordinate of touch location.

Preferably, can determine according to two-dimentional capacitance variations array the coordinate of touch location.Particularly, can adopt centroid algorithm to determine the coordinate of touch location according to two-dimentional capacitance variations array.

Figure 11 A shows an example of the coordinate that adopts the centroid algorithm calculated touch location.For succinct purpose, only calculated in the following description the coordinate of a dimension of touch location.It will be understood by those skilled in the art that the true coordinates that can adopt same or similar method to obtain touch location.Suppose that the induction electrode 56-58 shown in Fig. 6 is pointed covering, corresponding sensed data is respectively PT1, PT2, and PT3, and the corresponding coordinate of induction electrode 56-58 is respectively x1, x2, x3.The coordinate of the finger touch position that adopts centroid algorithm to obtain is:

$X_{\mathrm{touch}}=\frac{\mathrm{<figure-callout\; id="1"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}1*x1+\mathrm{<figure-callout\; id="2"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}2*x2+\mathrm{<figure-callout\; id="3"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}3*x3}{\mathrm{<figure-callout\; id="1"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}2+\mathrm{PT}3}---\left(1\right)$

Alternatively, after obtaining the coordinate of touch location, can also carry out step 66: analyze the data of frame in the past, in order to utilize the multiframe data to obtain current frame data.

Alternatively, also can carry out step 67 after obtaining the coordinate of touch location: according to the multiframe data, follow the tracks of touch track.In addition, can also, according to user's operating process, draw event information and report.

According to the capacitive touch screen of the utility model embodiment, can realize under the prerequisite of multi-point touch, solve the problem of noise stack in prior art.

The position 501 introducing power supply common-mode noises in Fig. 8 of take are example, below analyze the impact of noise on the calculating of touch location.

In the touch system detected based on the mutual capacitance touch of prior art, a plurality of driving passages (TX) and a plurality of receiving cable (RX) are arranged, and each RX is communicated with all TX.While having introduced a common mode interference signal in system, due to the connectedness of RX, noise can conduct on whole RX.Particularly, when on a RX, a plurality of noise source being arranged, the noise of these noise sources can superpose, thereby noise amplitude is increased.Voltage signal on the electric capacity that noise makes to measure etc. swings, thereby causes non-touch point to be reported by mistake.

In the capacitive touch screen provided at the utility model embodiment, there is no physical connection between each induction electrode before being connected to chip internal, noise can't transmit and superpose between induction electrode, has avoided wrong report.

Take the voltage detecting method as example, and noise can cause the change in voltage on the electrode that is touched, thereby causes that the sensed data of the electrode that is touched changes.Touch and detect principle according to self-capacitance, the influence value that the influence value that noise causes and normal touch cause all is proportional to the capped area of the electrode that is touched.

Figure 11 B shows the coordinate that adopts the centroid algorithm calculated touch location in noisy situation.Suppose that the influence value that normal touch causes is respectively PT1, PT2, PT3, the influence value that noise causes is PN1, PN2, PN3, (take induction electrode 56-58 as example):

PT1∝C58,PT2∝C57,PT3∝C56

PN1∝C58,PN2∝C57，PN3∝C56

Have: PN1=K*PT1, PN2=K*PT2, PN3=K*PT3, wherein K is constant.

When noise is consistent with the polarity of voltage of drive source, because the voltage final sensed data that superposes is:

PNT1=PN1+PT1=(1+K)*PT1

PNT2=PN2+PT2=(1+K)*PT2

PNT3=PN3+PT3=(1+K)*PT3

So, the coordinate that adopts centroid algorithm to obtain is:

$X_{\mathrm{touch}}\begin{array}{c}=\frac{\mathrm{<figure-callout\; id="1"\; label="PNT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PNT</figure-callout>}1*x1+\mathrm{<figure-callout\; id="2"\; label="PNT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PNT</figure-callout>}2*x2+\mathrm{<figure-callout\; id="3"\; label="PNT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PNT</figure-callout>}3*x3}{\mathrm{<figure-callout\; id="1"\; label="PNT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PNT</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="PNT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PNT</figure-callout>}2+\mathrm{<figure-callout\; id="3"\; label="PNT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PNT</figure-callout>}3}\\ =\frac{(1+K)*\mathrm{<figure-callout\; id="1"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}1*x1+(1+K)*\mathrm{<figure-callout\; id="2"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}2*x2+(1+K)*\mathrm{<figure-callout\; id="3"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}3*x3}{(\mathrm{<figure-callout\; id="1"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}2+\mathrm{PT}3)*(1+K)}\\ =\frac{\mathrm{<figure-callout\; id="1"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}1*x1+\mathrm{<figure-callout\; id="2"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}2*x2+\mathrm{<figure-callout\; id="3"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}3*x3}{(\mathrm{<figure-callout\; id="1"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}1+\mathrm{<figure-callout\; id="2"\; label="PT"\; filenames="DEST\_PATH\_HDA0000408704270000051.png,DEST\_PATH\_HDA0000408704270000052.png"\; state="\{\{state\}\}">PT</figure-callout>}2+\mathrm{PT}3)}\end{array}---\left(2\right)$

Visible, formula (2) equates with formula (1).Therefore, the capacitive touch screen of the utility model embodiment is immune to common-mode noise.As long as noise does not exceed the dynamic range of system, just can not have influence on final definite coordinate.

When the polarity of voltage of noise and drive source is contrary, can drag down useful signal.If the useful signal after dragging down can detect, from above analysis, do not affect final definite coordinate.If the useful signal after dragging down can not detect, the data failure of present frame.The sweep frequency of the capacitive touch screen but provided due to the utility model embodiment can be very high, and the N that can reach the conventional sweep frequency is (N is greater than 10 usually) doubly, utilizes this characteristic, can utilize the multiframe data to recover the data of present frame.It will be understood by those skilled in the art that due to the sweep frequency newspaper point rate required much larger than reality, therefore utilize the processing of multiframe data can not affect normal newspaper point rate.

Similarly, when noise limited exceeded the dynamic range of system, also can utilize the multiframe data to revise present frame, thereby obtain correct coordinate.The interframe disposal route is equally applicable to radio frequency and from the interference of other noise sources such as liquid crystal display module.

Above-mentioned explanation to the embodiment of institute's utility model, make those skilled in the art can realize or use the utility model.Multiple modification to these embodiment will be apparent for a person skilled in the art, and General Principle as defined herein can be in the situation that do not break away from scope of the present utility model, realization in other embodiments.Therefore, the utility model should not be restricted to disclosed these embodiment, but will meet the widest scope consistent with principle disclosed herein and features of novelty.

Claims (11)

1. a capacitive touch screen, is characterized in that, comprising:

Transparency protected cover plate;

Be arranged at a plurality of induction electrodes on described transparency protected cover plate surface, described a plurality of induction electrodes are arranged in two-dimensional array;

Be tied to the touch control chip on described transparency protected cover plate surface, described touch control chip is connected by wire respectively with each induction electrode among described a plurality of induction electrodes.

2. capacitive touch screen according to claim 1; it is characterized in that; also comprise: with the flexible circuit board that described touch control chip is connected, described touch control chip and described flexible circuit board are tied to described transparency protected cover plate surface by anisotropic conductive film ACF.

3. capacitive touch screen according to claim 2, is characterized in that, described transparency protected cover plate is provided with viewing area.

4. capacitive touch screen according to claim 3, is characterized in that, also comprises light shield layer, and described light shield layer is arranged at outside described transparency protected cover plate viewing area.

5. capacitive touch screen according to claim 4; it is characterized in that; described a plurality of induction electrode is arranged at described transparency protected cover plate lower surface; described touch control chip and described flexible circuit board are arranged at outside described transparency protected cover plate lower surface viewing area; described light shield layer is arranged at described transparency protected cover plate lower surface, and is positioned at the top of described touch control chip and described flexible circuit board.

6. capacitive touch screen according to claim 4, is characterized in that, also comprises the transparent membrane that is covered in described transparency protected cover plate upper surface.

7. capacitive touch screen according to claim 6; it is characterized in that; described a plurality of induction electrode is arranged at described transparency protected cover plate lower surface; described touch control chip and described flexible circuit board are arranged at outside described transparency protected cover plate lower surface viewing area, and described light shield layer is arranged at the lower surface of described transparent membrane.

8. capacitive touch screen according to claim 6, it is characterized in that described transparent membrane is fitted by full wafer optical cement and described transparency protected cover plate, or described transparent membrane is fitted by mouth word glue and described transparency protected cover plate.

9. according to the described capacitive touch screen of any one in claim 1 to 8, it is characterized in that, described touch control chip configuration is for detecting the self-capacitance of each induction electrode.

10. capacitive touch screen according to claim 9, is characterized in that, described touch control chip configuration is for to determine touch location according to two-dimentional capacitance variations array.

11. capacitive touch screen according to claim 9; it is characterized in that; described capacitive touch screen comprises a plurality of touch control chips that are tied on described transparency protected cover plate, and each touch control chip is for detection of the corresponding a part of induction electrode among described a plurality of induction electrodes.

Images