CN101673163B - A sensing circuit used in a capacitance touching control panel - Google Patents

A sensing circuit used in a capacitance touching control panel Download PDF

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Publication number
CN101673163B
CN101673163B CN 200910134850 CN200910134850A CN101673163B CN 101673163 B CN101673163 B CN 101673163B CN 200910134850 CN200910134850 CN 200910134850 CN 200910134850 A CN200910134850 A CN 200910134850A CN 101673163 B CN101673163 B CN 101673163B
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China
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capacitance
sensing
noise
reference signal
sensing signal
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CN 200910134850
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Chinese (zh)
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CN101673163A (en
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吴泽宏
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群创光电股份有限公司
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Abstract

The invention discloses a sensing circuit used in a capacitance touching control panel, which helps noise pass by adding a path, so as to reduce noise by differential treatment to the noise by going through two identical paths of same electrical doncitions, and the sensing signal can be correctly sensed.

Description

The sensing circuit that is used for capacitance type touch-control panel

Technical field

The invention discloses a kind of sensing circuit, particularly about a kind of sensing circuit for capacitance type touch-control panel.

Background technology

The at present application of contact panel is very extensive, and the screen, Automatic Teller Machine of information inquiry etc. are provided as mobile phone, public arena, and its intuitive operation replaces the function of keyboard and mouse, and is quite convenient in use.

Seeing also Fig. 1 and Fig. 2, is the schematic diagram of two kinds of capacitance type touch-control panels 150,250 sensing touched positions.In Fig. 1, capacitance type touch-control panel 150 comprises the sense wire of directions X and Y-direction, i.e. sense wire X 1To sense wire X 4And sense wire Y 1To sense wire Y 4, each sense wire has respectively several sensing electrodes (not shown), and the sense capacitance value of each sensing electrode is with sense capacitance C SenseExpression.When the touchless event occurs, this sense capacitance C SenseValue be zero, when having touch event to occur, this sense capacitance C SenseValue be not equal to zero.The capacitance type touch-control panel 150 of Fig. 1 is to come sensing touched position by the mode that order (Sequential) scans each sweep trace.As shown in Figure 1, scanning sequency is from sense wire Y 1Be scanned up to sense wire Y 4, and then from sense wire X 1Be scanned up to sense wire X 4For example, as sense wire X 4And sense wire Y 1Point of crossing when touched, by sense capacitance C SenseThe variation of capacitance, and learn touched position.

Another kind of sensing mode only scans the sweep trace of single direction, and the direction of scanning is not inputted excitation signal (Stimulating Signal), and as shown in Figure 2, capacitance type touch-control panel 250 comprises the sense wire of directions X and Y-direction equally, i.e. sense wire X 1To sense wire X 4And sense wire Y 1To sense wire Y 4, scanning sequency is from sense wire X 1Be scanned up to sense wire X 4, and sense wire Y 1To sense wire Y 4Directly input excitation signal.Be sense wire Y 1The input excitation signal sequentially scans sense wire X 1To sense wire X 4, follow sense wire Y 2The input excitation signal, more sequentially scan sense wire X 1To sense wire X 4, the rest may be inferred.Sense capacitance C TransRepresentative be sense wire X 1And sense wire Y 1Between coupling capacitance, sense wire X 1And sense wire Y 1When the point of crossing is touched and not touched, sense capacitance C TransHas different values.As Fig. 1, by checking sense capacitance C where TransCapacitance change, thereby learn touched position.

See also Fig. 3, be the calcspar of sensing circuit 100 in comprehensive above-mentioned schematic diagram prior art.Sensing circuit 100 comprises sensing cell 102 (sensing electrode), sensing signal generation unit 104 and integrator 106.Sensing cell 102 has the sense capacitance C of Fig. 1 SenseOr the sense capacitance C of Fig. 2 TransThe represented capacitance that is used to indicate the touchless generation, when the capacitance type touch-control panel 250 of the capacitance type touch-control panel 150 of Fig. 1 or Fig. 2 is touched, the capacitance of sensing cell 102 changes, 104 of sensing signal generation units produce a sensing signal according to capacitance variation, this sensing signal is voltage signal, input to integrator 106 and carry out integration, and integral result is exported to judge touched position.

Yet, no matter be the capacitance type touch-control panel 150 of Fig. 1 or the capacitance type touch-control panel 250 of Fig. 2, all exist the problem of noise effect sensing signal.Know as one of skill in the art, sensing cell 102 is to be made on sensing electrode substrate (not shown), and sensing signal generation unit 104 and integrator 106 are made on array (Array) substrate (not shown) of liquid crystal panel.Has a common voltage electrode (Common Electrode between the array base palte of sensing electrode substrate and liquid crystal panel; Not shown) in order to liquid crystal panel required voltage quasi position of when operation to be provided.When liquid crystal panel operated, the common electric voltage signal that the common voltage electrode provides was unclean, that is contains noise, source bus line (SourceBus when for example driving liquid crystal panel; Not shown) precharge (Pre-Charge) and the conducting of switch and disconnect action etc. and can produce noise, this noise can enter the sensing circuit 100 of Fig. 3, easily causes the problem of can't the sensing touched position of sensing circuit 100 or sensing mistake to occur.

Therefore need a kind of method to solve the problem of above-mentioned noise effect sensing signal.

Summary of the invention

For addressing the above problem, the object of the present invention is to provide a kind of sensing circuit for capacitance type touch-control panel, it is the size of reducing noise significantly, makes the sensing signal can be by correct sensing.

For achieving the above object, the present invention adopts following technical scheme: a kind of sensing circuit for capacitance type touch-control panel comprises a sensing signal section, a reference signal section and an integrator.Sensing signal section is in order to based on the capacitance of capacitance type touch-control panel and a noise of reception, and to produce a sensing signal, the capacitance of this capacitance type touch-control panel is in the situation that touched and not touched different.Reference signal section being in order to receiving this noise and to export a reference signal, and has the electric condition identical with sensing signal section.Integrator is subtracted each other sensing signal and reference signal in order to receive sensing signal and reference signal, and produces an output signal.

For achieving the above object, the present invention also adopts following technical scheme: a kind of sensing circuit for capacitance type touch-control panel comprises a sensing signal path, a reference signal path and one first differential amplifier.The sensing signal path is in order to based on the capacitance of capacitance type touch-control panel and a noise of reception, and to produce a sensing signal, the capacitance of this capacitance type touch-control panel is in the situation that touched and not touched different.The reference signal path being in order to receiving this noise and to export a reference signal, and has the electric condition identical with the sensing signal path.The first differential amplifier is subtracted each other sensing signal and reference signal in order to receive sensing signal and reference signal, and produces an output signal.

Compared with prior art, the present invention passes through for noise by increasing by a path, make noise via electric condition identical two paths by after subtracting each other again, significantly lower the size of noise in sensing signal, make the only signal that produces of remaining sensing element and can by correct sensing, increase sensitivity and the correctness of sensing circuit of output.

The present invention is described further below in conjunction with accompanying drawing and embodiment.

Description of drawings

Fig. 1 and Fig. 2 are the schematic diagram of two kinds of capacitance type touch-control panel sensing touched positions.

Fig. 3 is the calcspar of sensing circuit in the schematic diagram prior art.

Fig. 4 is the calcspar according to sensing circuit of the present invention.

Fig. 5 is the circuit diagram according to the first embodiment of Fig. 4.

Fig. 6 is the circuit diagram according to the second embodiment of Fig. 4.

Fig. 7 is that an electronic installation comprises a capacitance type touch-control panel, and wherein capacitance type touch-control panel comprises according to sensing circuit of the present invention.

Embodiment

Relevant detailed description of the present invention and technology contents, existing as follows with regard to accompanying drawings.The explanation of following examples is with reference to additional diagram, is used for the specific embodiment that illustration the present invention can be used for implementing.

See also Fig. 4, be the calcspar according to sensing circuit 400 of the present invention.Sensing circuit 400 can reduce the noise S that produces because of common voltage electrode 440 in capacitance type touch-control panel (not shown) NoiseImpact.Sensing circuit 400 consists essentially of a sensing signal section 411, a reference signal section 421 and an integrator 406.Sensing signal section 411 is in order to based on the capacitance of capacitance type touch-control panel and the noise S of reception NoiseProduce a sensing signal S tThe capacitance of capacitance type touch-control panel is in the situation that touched and not touched different.Reference signal section 421 is in order to receive noise S NoiseAnd export a reference signal S Noise'.This reference signal section 421 is analog sensing signal sections 411 and have the electric condition identical with sensing signal section 411.Integrator 406 is in order to receive sensing signal S tAnd reference signal S Noise', its characteristic is that the difference with two input ends gives integration, so integrator 406 is with sensing signal S tAnd reference signal S Noise' subtracted each other, and produce an output signal S out

Reference signal section 421 has a capacitance, and the capacitance when this capacitance is not touched with sensing signal section 411 in fact equates.Sensing signal section 411 and reference signal section 421 electric conditions are identical refers to that the electronic component of reference signal section 421 and these electronic component connected modes are the equivalent electrical circuit of analog sensing signal section 411, so that the electrical specifications such as both impedances, capacitance are consistent as far as possible, its purpose is to make noise S NoiseBy identical circuit, guarantee noise S NoiseValue by entering integrator 406 after sensing signal section 411 and reference signal section 421 is identical as far as possible.

For making the present invention be easier to understand, below with comparative descriptions prior art and difference of the present invention.See also Fig. 5, be the circuit diagram according to the first embodiment of Fig. 4.This embodiment is for scanning the sensing circuit 500 of the capacitance type touch-control panel of other direction after scanning one direction again.Sensing signal section 511 comprises a sensing cell 512 and a sensing signal generation unit 514.Reference signal section 521 comprises a reference unit 522 and a reference signal generation unit 524.

Sensing cell 512 has a sense capacitance value, namely with sense capacitance C SenseThe expression capacitance.When capacitance type touch-control panel is not touched, the sense capacitance C of sensing cell 512 SenseCapacitance be zero, when capacitance type touch-control panel is touched, sense capacitance C SenseCapacitance non-vanishing.In addition, sensing cell 512 also has parasitic capacitance value, for the equivalent capacitance value between common voltage electrode 540 and sensing electrode substrate, with stray capacitance C Par1Expression.The noise S of common voltage electrode 540 NoiseVia stray capacitance C Par1Be coupled to sensing cell 512.

Sensing cell 512 is via stray capacitance C Par1Receive noise S Noise, and have one first equivalent capacitance value or one second equivalent capacitance value.The first equivalent capacitance value is capacitance (the sense capacitance C of capacitance type touch-control panel when touched SenseCapacitance) and stray capacitance C Par1The equivalent capacitance value of capacitance, the second equivalent capacitance value is capacitance (the sense capacitance C of capacitance type touch-control panel when not touched SenseCapacitance be zero) and stray capacitance C Par1The equivalent capacitance value of capacitance.Sensing signal generation unit 514 is coupled to sensing cell 512, according to the first equivalent capacitance value and noise S Noise, or according to the second equivalent capacitance value and noise S NoiseProduce sensing signal S t

The signal of the node 1 of Fig. 5 comprises control signal V ToggleThe part that (as a square wave) produces and noise S NoiseThe part that produces.Control signal V ToggleBe the signal that adds, be used for reaction and have or not the event of touching (that is sense capacitance C SenseValue) generation, i.e. control signal V ToggleBe used for the first equivalent capacitance value or the second equivalent capacitance value are converted to the variation of signal, have or not with expression the event of touching, wherein control signal V ToggleSee through one first coupling capacitance C c1Be coupled to sensing signal generation unit 514.As for noise S NoiseSee through stray capacitance C Par1Coupling and result from the part S of node 1 1noiseCan be tried to achieve by following (1) formula:

S 1 noise = S noise ( C par 1 C par 1 + C c 1 + C sense ) - - - ( 1 )

Noise S NoiseBy sensing signal section 511, the present invention sets up another path for the noise S of common voltage electrode 540 except meeting NoiseBy.Reference unit 522 receives noise S NoiseAnd has a C grade effect capacitance.C grade effect capacitance is capacitance and the stray capacitance C of artificial capacitor formula contact panel when not touched Par1The equivalent capacitance value of capacitance, namely have the numerical value identical with the second equivalent capacitance value of sensing cell 512.Therefore reference unit 522 has a capacitor C Par2, in order to the analog parasitic capacitor C Par1Noise S NoiseSee through capacitor C Par2Be coupled to reference unit 522.As mentioned above, stray capacitance C Par1Be the equivalent capacity between common voltage electrode 540 and sensing electrode substrate, can get by measurement, and capacitor C Par2Be a capacitor that adds, have and stray capacitance C Par1The capacitance that equates in fact.

The circuit of reference signal generation unit 524 is identical with the circuit of sensing signal generation unit 514, and imitates capacitance and noise S according to the C grade of reference unit 522 NoiseOutput reference signal S Noise'.Reference signal generation unit 524 has second a coupling capacitance C who adds c2, for the electric condition that makes reference signal section 521 is identical with the electric condition of sensing signal section 511, control signal V ToggleAs seeing through the first coupling capacitance C ciBe coupled to as sensing signal generation unit 514, also see through the second coupling capacitance C c2Be coupled to reference signal generation unit 524, so that noise S NoiseElectric condition by reference signal section 521 is with identical by the electric condition of sensing signal section 511.The second coupling capacitance C wherein c2Capacitance and the first coupling capacitance C c1Capacitance equal in fact.So noise signal S of node 2 2noiseFor:

S 2 noise = S noise ( C par 2 C par 2 + C c 2 )

Due to capacitor C Par2Capacitance and stray capacitance C Par1Capacitance equal in fact, and the second coupling capacitance C c2Capacitance and the first coupling capacitance C c1Capacitance equal in fact, therefore:

S 2 noise = S noise ( C par 1 C par 1 + C c 1 )

The noise difference of 506 liang of input ends of input integral device is:

S 1 noise - S 2 noise = S noise ( C par 1 C par 1 + C c 1 + C sense - C par 1 C par 1 + C c 1 )

= S noise [ - C par 1 × C sense ( C par 1 + C c 1 + C sense ) × ( C par 1 + C c 1 ) ] - - - ( 2 )

The noise S that compares the prior art of (1) formula 1noiseNoise (S with the first embodiment of (2) formula 1noise-S 2noise) can get, the size of the noise of (2) formula reduces than the size of the noise of (1) formula Doubly, can get rid of noise S via the signal after integrator 506 integrations Noise, and the sensitivity of increase sensing circuit 500.

Sensing signal section 511 can comprise that preferably one first wave filter 518 is coupled between sensing signal generation unit 514 and integrator 506, in order to the sensing signal S of filtering via 514 generations of sensing signal generation unit tHFS.According to sensing signal section 511, reference signal section 521 comprises that preferably one second wave filter 528 is coupled between reference signal generation unit 524 and integrator 506, and the circuit of the second wave filter 528 is identical with the circuit of the first wave filter 518, in order to filtering reference signal S Noise' HFS.

In the present embodiment, the first wave filter 518 comprises one the 3rd resistance R 3Be coupled between sensing signal generation unit 514 and integrator 506; And one the 3rd capacitor C 3Be coupled between integrator 506 and an earth terminal.The second wave filter 528 comprises one the 4th resistance R 4Be coupled between reference signal generation unit 524 and integrator 506; And one the 4th capacitor C 4Be coupled between integrator 506 and an earth terminal.For the circuit that makes the first wave filter 518 is identical with the circuit of the second wave filter 528, the 3rd resistance R 3Resistance value and the 4th resistance R 4Resistance value equal in fact, the 3rd capacitor C 3Capacitance and the 4th capacitor C 4Capacitance equal in fact.

Integrator 506 comprises one first differential amplifier 532, one first resistance R 1And one first capacitor C 1The first differential amplifier 532 has an inverting input (-), a non-inverting input (+) and an output node 4.The first resistance R 1Be coupled between sensing signal section 511 and inverting input (-).The first capacitor C 1Be coupled between inverting input (-) and output node 4.For making noise S NoiseThe path of passing through before 532 two input ends of the first differential amplifier is identical entering, and integrator 506 has more ground connection matching unit 536 use to input the circuit of non-inverting input (+) of the first differential amplifier 532 identical with the circuit of inverting input (-) of input the first differential amplifier 532.Ground connection matching unit 536 comprises one second resistance R 2And one second capacitor C 2, and the second resistance R 2Value must design and the first resistance R 1Value equate, the second capacitor C 2Value must with the first capacitor C 1Value equate.The second resistance R 2Be coupled between the non-inverting input (+) of reference signal section 521 and the first differential amplifier 532 the second capacitor C 2Be coupled between the non-inverting input (+) and an earth terminal of the first differential amplifier 532.

Sensing signal section 511 adds the first resistance R in integrator 506 1And first capacitor C 1Consist of according to touchless and noise S are arranged NoiseThe sensing signal S that produces tThe fullpath that passes through can be considered sensing signal path 510.And the second resistance R in reference signal section 521 and integrator 506 2, the second capacitor C 2Consist of noise S NoiseThe path of passing through can be considered reference signal path 520.Reference signal path 520 is analog sensing signal paths 510, so that the electric condition in two paths is identical.

Output terminal at integrator 506 more can be coupled to an amplifying unit 530, the output signal S that produces in order to amplify integrator 506 outAmplifying unit 530 comprises one second differential amplifier 534, the 5th resistance R 5And the 6th resistance R 6The second differential amplifier 534 has an inverting input (-), a non-inverting input (+) and an output node 3, and non-inverting input (+) is coupled to the output node 4 of integrator 506.The 5th resistance R 5Be coupled between inverting input (-) and an earth terminal.The 6th resistance R 6Be coupled between inverting input (-) and output node 3.

The switch SW of sensing signal generation unit 514 1In order to switch the different scanning line, each sweep trace comprises several sensing cells 512, and the remainder element comprises the part that integrator 506, the first wave filter 518, reference unit 522, reference signal generation unit 524, ground connection matching unit 536, the second wave filter 528 and amplifying unit 530 are shared for all sweep traces.

On the side circuit layout, sensing signal generation unit 514, the first wave filter 518, reference signal section 521, integrator 506 and amplifying unit 530 are integrated in the array base palte of liquid crystal panel usually, or being independent of array base palte makes.As mentioned above, each sensing cell 512 is the sensing electrode in capacitance type touch-control panel, for being made on the sensing electrode substrate.

See also Fig. 6, be the circuit diagram according to the second embodiment of Fig. 4.This embodiment only scans a direction for being used for, the embodiment of sensing circuit 600 in the capacitance type touch-control panel of other direction input excitation signal.Sensing signal section 611 comprises a sensing cell 612 and a sensing signal generation unit 614.Reference signal section 621 comprises a reference unit 622 and a reference signal generation unit 624.

When capacitance type touch-control panel was touched, sensing cell 612 had a sense capacitance value, namely with sense capacitance C TransThe expression capacitance.Capacitance when capacitance type touch-control panel is not touched, the i.e. capacitor C of reference unit 622 artificial capacitor formula contact panels when not touched Trans' the expression capacitance.In addition, sensing cell 612 also has parasitic capacitance value, for the equivalent capacitance value between common voltage electrode 640 and sensing electrode substrate, with stray capacitance C Par3And stray capacitance C Par5Expression.The noise S of common voltage electrode 640 NoiseVia stray capacitance C Par3Be coupled to sensing cell 612.

Sensing cell 612 is via stray capacitance C Par3Receive noise S Noise, and have one first equivalent capacitance value or one second equivalent capacitance value.The first equivalent capacitance value is capacitance (the sense capacitance C of capacitance type touch-control panel when touched TransThe expression capacitance) and stray capacitance C Par3, C Par5The equivalent capacitance value of capacitance, the second equivalent capacitance value is the capacitor C of capacitance type touch-control panel when not touched Trans' expression capacitance and stray capacitance C Par3, C Par5The equivalent capacitance value of capacitance.Sensing signal generation unit 614 is coupled to sensing cell 612, according to the first equivalent capacitance value and noise S Noise, or according to the second equivalent capacitance value and noise S NoiseProduce sensing signal S t

The signal of the node 5 of Fig. 6 comprises control signal V ToggleThe part that (as a square wave) produces and noise S NoiseThe part that produces.Control signal V ToggleBe the signal that adds, be used for reaction and have or not the event of touching (that is sense capacitance C TransValue) generation, i.e. control signal V ToggleBe used for the first equivalent capacitance value or the second equivalent capacitance value are converted to the variation of signal, have or not with expression the event of touching, wherein control signal V ToggleDirectly be applied to sensing cell 612 and sensing signal generation unit 614.As for noise S NoiseSee through stray capacitance C Par3Coupling and result from the part S of node 5 5noiseCan be tried to achieve by following (3) formula:

S 5 noise = S noise ( C par 3 C par 3 + C trans ) - - - ( 3 )

Noise S NoiseBy sensing signal section 611, the present invention sets up another path for the noise S of common voltage electrode 640 except meeting NoiseBy.Reference unit 622 receives noise S NoiseAnd has a C grade effect capacitance.C grade effect capacitance is the capacitor C of artificial capacitor formula contact panel when not touched Trans' expression capacitance and stray capacitance C Par3, C Par5The equivalent capacitance value of capacitance, namely have the numerical value identical with the second equivalent capacitance value of sensing cell 612.Therefore reference unit 622 has capacitor C Par4And capacitor C Par6Represent respectively the analog parasitic capacitor C Par3, C Par5Noise S NoiseSee through capacitor C Par4Be coupled to reference unit 622.Identical with the first embodiment of Fig. 5, capacitor C Par4And capacitor C Par6Be the capacitor that adds, have respectively and stray capacitance C Par3And capacitor C Par5The capacitance that equates in fact.

The circuit of reference signal generation unit 624 is identical with the circuit of sensing signal generation unit 614, and imitates capacitance and noise S according to the C grade of reference unit 622 NoiseOutput reference signal S Noise'.For the electric condition that makes reference signal section 621 is identical with the electric condition of sensing signal section 611, control signal V ToggleAlso directly be applied to reference unit 622 and reference signal generation unit 624 as being applied to as sensing cell 612 and sensing signal generation unit 614, so that noise S NoiseElectric condition by reference signal section 621 is with identical by the electric condition of sensing signal section 611.So noise S of node 6 6noiseFor:

S 6 noise = S noise ( C par 4 C par 4 + C trans ′ )

Due to capacitor C Par4Capacitance and stray capacitance C Par3Capacitance equal in fact, therefore:

S 6 noise = S noise ( C par 3 C par 3 + C trans ′ )

The noise difference of 606 liang of input ends of input integral device is:

S 5 noise - S 6 noise = S noise ( C par 3 C par 3 + C trans - C par 3 C par 3 + C tarns ′ )

= S noise [ C par 3 × C trans ′ - C par 3 × C trans ( C par 3 + C trans ) × ( C par 3 + C trans ′ ) ] - - - ( 4 )

The noise S that compares the prior art of (3) formula 5noiseNoise (S with the second embodiment of (4) formula 5noise-S 6noise) can get, the size of the noise of (4) formula reduces than the size of the noise of (3) formula Doubly, can get rid of noise S via the signal after integrator 606 integrations Noise, and the sensitivity of increase sensing circuit 600.

In the embodiment of circuit, the side circuit of the first wave filter 618, the second wave filter 628, integrator 606, ground connection matching unit 636 and amplifying unit 630 is as described in the first embodiment of above-mentioned Fig. 5, so repeat no more.

As Fig. 5, the 7th resistance R that sensing signal section 611 adds in integrator 606 7And the 7th capacitor C 7Consist of according to touchless and noise S are arranged NoiseThe sensing signal S that produces tThe fullpath that passes through can be considered sensing signal path 610.And the 8th resistance R in reference signal section 621 and integrator 606 8, the 8th capacitor C 8Consist of noise S NoiseThe path of passing through can be considered reference signal path 620.620 analog sensing signal paths 610, reference signal path are so that the electric condition in two paths is identical.

Compared with prior art, the present invention passes through for noise by increasing the reference signal path, make noise via the identical sensing signal path of electric condition and reference signal path by after export two input ends of differential amplifier to, see through after differential amplifier subtracts each other the noise of two paths, significantly lower the size of noise in sensing signal, the output that makes differential amplifier is the signal that produces of remaining sensing element and can by correct sensing, increase sensitivity and the correctness of sensing circuit only.

Fig. 7 is that an electronic installation 700 comprises a capacitance type touch-control panel 750, wherein capacitance type touch-control panel 750 comprise according to sensing circuit 400 of the present invention, 500 and 600 one of them.Comprise as Fig. 4 to sensing circuit 400 shown in Figure 6,500 and 600 one of them capacitance type touch-control panel 750 can be the part of electronic installation 700.Electronic installation 700 comprises capacitance type touch-control panel 750 and a power supply unit 740, and power supply unit 740 couples to supply power to capacitance type touch-control panel 750 with capacitance type touch-control panel 750.Electronic installation 700 can be display on mobile phone, digital camera, personal digital assistant, mobile computer, desktop PC, TV, satellite navigation, car, aviation with display or portable digital video disk (Digital Video Disc, DVD) projector etc.

Although the present invention discloses as above with embodiment; so it is not to limit the present invention, any those skilled in the art, without departing from the spirit and scope of the present invention; when can do various changes and retouching, so protection scope of the present invention is as the criterion when looking appended the claim person of defining.

Claims (11)

1. sensing circuit that is used for capacitance type touch-control panel, it is characterized in that: comprising: a sensing signal section, a reference signal section and an integrator, wherein this sensing signal section is in order to based on the capacitance of this capacitance type touch-control panel and a noise of reception, to produce a sensing signal, the capacitance of this capacitance type touch-control panel is in the situation that touched and not touched different; This reference signal section is in order to receiving this noise and to export a reference signal, and this reference signal section has the electric condition identical with this sensing signal section; Integrator is in order to receive this sensing signal and this reference signal, this sensing signal and this reference signal are subtracted each other, and produce an output signal, this integrator comprises: one first differential amplifier, one first resistance and one first electric capacity, and wherein this first differential amplifier has an inverting input, a non-inverting input and an output node; This first resistance has a first end and is coupled to this sensing signal section, and one second end is coupled to this inverting input; This first electric capacity has a first end and is coupled to this inverting input, and one second end be coupled to this output node, this integrator more comprises a ground connection matching unit, this ground connection matching unit comprises: one second resistance and one second electric capacity, wherein this second resistance has a first end and is coupled to this reference signal section, and one second end is coupled to this non-inverting input; This second electric capacity has a first end and is coupled to this non-inverting input, and one second end be coupled to an earth terminal, wherein the resistance value of this second resistance equates with the resistance value of this first resistance in fact, and the capacitance of this second electric capacity equates with the capacitance of this first electric capacity in fact.
2. sensing circuit as claimed in claim 1 is characterized in that: this reference signal section has a capacitance, and the capacitance when this capacitance is not touched with this sensing signal section in fact equates.
3. sensing circuit as claimed in claim 1 is characterized in that: this reference signal section has several electronic packages, and these electronic components are for connecting to simulate the equivalent electrical circuit of this sensing signal section.
4. sensing circuit as claimed in claim 1, it is characterized in that: this sensing signal section comprises: a sensing cell and a sensing signal generation unit, wherein this sensing cell receives this noise via a stray capacitance, this sensing cell has one first equivalent capacitance value or one second equivalent capacitance value, this first equivalent capacitance value is the capacitance of this capacitance type touch-control panel when touched and the equivalent capacitance value of the capacitance of this stray capacitance, this second equivalent capacitance value is the capacitance of this capacitance type touch-control panel when not touched and the equivalent capacitance value of the capacitance of this stray capacitance, this sensing signal generation unit is coupled to this sensing cell, according to this first equivalent capacitance value and this noise, or produces this sensing signal according to this second equivalent capacitance value and this noise, and
This reference signal section comprises: a reference unit and a reference signal generation unit, this reference unit receives this noise and has a C grade effect capacitance, the equivalent capacitance value of the capacitance of this C grade effect capacitance capacitance when not touched and this stray capacitance for this capacitance type touch-control panel of simulation; This reference signal generation unit is coupled to this reference unit, export this reference signal according to this C grade effect capacitance and this noise, wherein this reference unit has the circuit identical with this sensing cell, and this reference signal generation unit has the circuit identical with the sensing signal generation unit.
5. sensing circuit as claimed in claim 4, it is characterized in that: this sensing signal section comprises that more one first wave filter is coupled between this sensing signal generation unit and this integrator, the HFS of this sensing signal that produces via this sensing signal generation unit in order to filtering; This reference signal section comprises that more one second wave filter is coupled between this reference signal generation unit and this integrator, and the circuit of this second wave filter is identical with the circuit of this first wave filter, in order to the HFS of this reference signal of filtering.
6. sensing circuit as claimed in claim 4 is characterized in that: comprising: one first coupling capacitance and one second coupling capacitance, and a control signal is coupled to this sensing signal generation unit via this first coupling capacitance; This control signal is coupled to this reference signal generation unit via this second coupling capacitance, and wherein the capacitance of this first coupling capacitance equates with the capacitance of this second coupling capacitance in fact.
7. sensing circuit as claimed in claim 4, it is characterized in that: this reference unit comprises an electric capacity, the capacitance of this electric capacity equates with the capacitance of this stray capacitance in fact, and this noise sees through this and is capacitively coupled to this reference unit.
8. sensing circuit that is used for capacitance type touch-control panel, it is characterized in that: comprising: a sensing signal path, a reference signal path and one first differential amplifier, wherein this sensing signal path is in order to based on the capacitance of this capacitance type touch-control panel and a noise of reception, to produce a sensing signal, the capacitance of this capacitance type touch-control panel is in the situation that touched and not touched different; This reference signal path is in order to receiving this noise and to export a reference signal, and this reference signal path has the electric condition identical with this sensing signal path; This first differential amplifier is subtracted each other this sensing signal and this reference signal in order to receive this sensing signal and this reference signal, and produces an output signal.
9. sensing circuit as claimed in claim 8 is characterized in that: this reference signal path has a capacitance, and the capacitance when this capacitance is not touched with this sensing signal path in fact equates.
10. sensing circuit as claimed in claim 8 is characterized in that: this reference signal path has several electronic packages, and these electronic components are for connecting to simulate the equivalent electrical circuit in this sensing signal path.
11. an electronic installation is characterized in that: comprising:
One capacitance touching control road deck, comprise sensing circuit as described in claim 1 or 8, wherein this electronic installation is display on a mobile phone, a digital camera, a personal digital assistant, a mobile computer, a desktop PC, a TV, a satellite navigation, a car, an aviation with display or a portable digital video disk projector.
CN 200910134850 2008-09-08 2009-04-09 A sensing circuit used in a capacitance touching control panel CN101673163B (en)

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CN101673163B true CN101673163B (en) 2013-11-06

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