TW201519060A - Method for recognizing touch signal and device thereof - Google Patents

Abstract

A method for recognizing touch signal comprises: using forward signal measurement to charge a drive electrode, in which an inductive electric field is formed between the drive electrode and an inductive electrode, and a first voltage signal is read and obtained by using an analog-to-digital signal conversion circuit; using reverse signal measurement, given that the drive electrode is continuously driven, to switch the inductive electrode from the ground state to the float state; then using the analog-to-digital signal conversion circuit to temporarily charge the inductive electrode, and measuring the inductive voltage until the voltage is stabilized to obtain a second voltage signal. When the first voltage signal is deducted from the second voltage signal, noise such as electromagnetic wave interference contained in the environment and power on the inductive electric field will be eliminated.

Description

Method and device for recognizing touch signals

The present invention relates to a device and method for recognizing the position information of a touch signal by using an induced electric field change, and more particularly to a touch panel having a polar substance such as an impurity on the surface, which can accurately determine the position information of the touch signal. method.

The current capacitive touch panel includes a data processing module, a driving electrode, and a sensing electrode. The driving electrode and the sensing electrode are electrically connected to the data processing module via respective interfaces. The driving electrode is composed of a plurality of driving electrode strips parallel to each other, and the sensing electrode is composed of a plurality of mutually parallel sensing electrode strips, wherein each driving electrode strip and each sensing electrode strip are arranged perpendicular to each other to form a plurality of intersections. . When the driving electrode is driven by the driving voltage, an electric field is formed between the driving electrode and the sensing electrode, so that the sensing electrode generates an induced charge, and has an alternating capacitance, and the plurality of driving electrode strips and the plurality of sensing electrode strips form a plurality of electric fields, so It can be imagined that each intersection has an alternating capacitance, and a plurality of intersections form an array of alternating capacitors. The alternating capacitance array has a stable capacitance (hereinafter referred to as a base capacitance) in a steady state environment, so that the sensing electrode generates an induced voltage (the induced voltage is referred to as a substrate voltage), and the data processing module reads through the interface thereof. Take the induced voltage. When a finger or other conductive material approaches the intersection, the electric field at that location will change, causing a change in the induced voltage. Induced voltage of change to the data office After the module is transmitted, the analog-to-digital converter converts the digital signal into a digital signal, and then determines whether it is a touch signal through an algorithm, determines whether to perform the calculation of the touch position, and then processes the touch output to the host end. Touch the information to enter the data. The host side is a device having at least one central processing unit (CPU) control, such as a computer, a PDA, various digital audio and video devices with display screens, and the like.

A capacitive touch panel, which is exemplified by WO 97/23738, provides a capacitive coupling element that is configured as a touch sensing switch. The embodiment discloses a measurement cycle as follows. In the driving part, the sensing circuit is charged by using a driving circuit, and then in the measuring part, the charge transferred by the sensing switch is measured by a charge detecting circuit. . The charging and transferring portions of the above measurement cycle can vary widely, and the signal measurement range can be selected according to the relevant application. Even if an interfering substance is present, the presence of a nearby object can be detected due to a change in the amount of induced charge on the sensing switch.

In another prior art, in WO 00/44018, a pair of electrodes is used as a sensing switch to detect the presence of a human body such as a user's finger via a change in the amount of charge transferred between the two electrodes. One of the pair of electrodes X is driven by the driving circuit, and the other electrode Y is connected to the charge measuring circuit, and a charge measuring circuit detects the amount of charge existing on the electrode Y when the electrode X is driven. In addition, it is further disclosed that a plurality of pairs of electrodes can be configured to form a matrix of sensing regions, which can improve the efficiency of implementation of the two-dimensional positional contact sensor.

Since the electric field formed between the driving electrode and the sensing electrode is easily disturbed by external electromagnetic waves or the like, the change in the amount of charge of the capacitive charging transfer caused by the conductive substance such as a finger cannot be accurately measured. Therefore, in the prior art, there is a method of subtracting the noise by means of signal subtraction, which repeats a measurement cycle to obtain two or more different sensing voltages. The signal is subtracted to obtain a touch signal. The measuring cycle first grounds the driving electrode and the sensing electrode, removes the residual charge, and uses the analog logarithm to perform the first measurement for the converter to obtain a sensing signal A; then the sensing electrode is floated, waiting for the driving signal to drive The electrode is charged; then, the driving electrode is charged at a fixed voltage, and the sensing electrode generates an induced voltage; then, the second measurement is performed by using the analog logarithm to obtain a sensing signal B; and then the driving electrode is simultaneously The sensing electrode is grounded, the residual charge is removed, and the next measurement cycle is awaited; the sensing signal B is subtracted from the sensing signal A to obtain a value C, which is compared with a preset threshold value, above which the threshold value is exceeded. When it is judged as a touch signal.

For example, US 12/466,230 compares the range of accepted values between the plurality of signal values obtained by the measurement cycle and the preset maximum and minimum values, discards the signal beyond the range, and utilizes one or a range within the preset acceptance range. Multiple signal changes to determine the presence of the human body; and TW 100112718, which scans the rows and columns of the touch screen capacitance matrix separately, and simultaneously scans two or two columns to obtain capacitance differences of two or two columns, or scans One row or one column, obtain the capacitance difference between the row or column and its reference capacitance, and then perform data processing.

The above method will slow down the reaction time because it is necessary to measure the sensing electrode when the driving electrode is not charged. Moreover, when there is water on the surface of the touch panel, a finger or other conductive object touches the touch panel, and the power line between the electrodes is reduced due to the touch, and the long-distance power line on the driving electrode is easily coupled back to the sensing electrode, thereby not only failing to make The induced voltage between the driving electrode and the sensing electrode is reduced, but may increase, or an induced voltage signal is generated at other sensing electrodes, resulting in a decrease in the amount of voltage change that touches the touch panel. Therefore, the existing capacitive touch panel technology causes a decrease in sensitivity, causing the user to feel that the touch panel has poor waterproof performance and poor anti-interference performance.

In view of the foregoing background, the present invention provides an improved method and device for recognizing a touch signal, which effectively eliminates interference of signal detection of noise and shortens signal processing time.

The method for recognizing a touch signal is applied to a touch panel, and the method includes: providing at least one driving electrode and at least one sensing, in order to achieve the above-mentioned one or a part or all of the objectives or other purposes. The electrode is switched from a grounded state to a floating state; the driving electrode is charged to a high potential, and the sensing electrode is in a floating state; by an analog to digital converter (ADC), The sensing electrode is measured to generate a first voltage signal; the switching sensing electrode is restored from the floating state to the ground state; the driving electrode is kept charged at a high potential, and the sensing electrode is switched from the ground state to the floating state; The digital signal conversion circuit charges the sensing electrode; stops charging the sensing electrode, so that the driving electrode is lowered from a high potential to a low potential, and the sensing electrode is still in a floating state; the analog electrode is measured by an analog digital signal conversion circuit Measuring to generate a second voltage signal; and calculating the first voltage signal and the second power The difference signal to obtain a sensing signal.

If no conductive material such as a pointing object touches the touch panel, the sensing signal is defined as a substrate signal S _{b (base)} and stored in a register of the control unit; if a conductive object such as a finger touches the touch object In the panel, the sensing signal is defined as a contact signal S _{f (finger)} , and the method further includes calculating a difference between the contact signal S _f and the substrate signal S _b to generate a touch signal S _T . Then, a control unit compares the voltage value of the touch signal S _T with a threshold value preset by the controller. When the voltage value of the touch signal S _T is less than or equal to the threshold value, the control unit outputs the touch. The control signal is transmitted to the host end; when the voltage value of the touch signal S _T is greater than the threshold value, the touch signal S _{T is} excluded, and the control unit does not operate on the touch signal, and does not transmit to the host end, and uses the signal The method of subtraction can be deducted from the effects of noise.

In an embodiment, the register of the control unit of the present invention has the function of recording a plurality of sets of sensing signals, so that a plurality of sets of sensing signals S _b1 , S _{b2 are} obtained by repeating a plurality of measuring cycles. S _b3 , . . . , and a plurality of sets of sensing signals S _f1 , S _f2 , S _bf3 , . . . etc., using the algorithm of the control unit memory to obtain the sensing signals S _b1 , S _b2 , S _b3 , The average value of S _ba(average) , and then the average value of the sensing signals S _f1 , S _f2 , S _bf3 , ... S _{fa (average)} , and then the signal subtraction calculation can be more accurate The touch signal S _T ; in addition, a touch signal S _T can be obtained in each measurement cycle, and temporarily stored in the register to obtain the touch signals S _T1 , S _T2 , S _T3 , The average value of S _Ta(average) is transmitted to the host. When the average value is calculated, the control unit can delete the maximum and minimum signals in the signal group first, and then calculate the average value to obtain more accurate. Touch signal S _T .

The embodiment of the present invention can provide better noise processing capability by the above method for recognizing a touch signal. First, when the forward signal measurement is used in the first stage, by charging the driving electrode, an induced electric field is formed between the driving electrode and the sensing electrode to have an induced capacitance, and then the sensing electrode generates an induced voltage. The first voltage signal is obtained by reading the analog digital signal conversion circuit. Then, when the reverse signal measurement is used in the second stage, the sensing electrode is switched from the ground state to the floating state while the driving electrode is continuously driven. The state is further charged by the analog digital signal conversion circuit for the induction electrode, and after the voltage is stabilized, the induced voltage is measured to obtain the second voltage signal. When the second voltage signal is subtracted from the first voltage signal, the electromagnetic interference caused by the electromagnetic wave in the environment and the electromagnetic wave interference caused by the LCD driver, etc., will be deducted, especially the low frequency. The noise.

When only the driving and signal detecting methods of the prior art are used, it is easy to cause misunderstanding of noise, and it is easy to reduce the amount of signals that can be used. The invention utilizes the difference of the touch signal characteristics to achieve the purpose of enhancing the signal and reducing the noise. When the first voltage signal measured by the forward signal in the first stage is affected by the conductive material such as a finger, the voltage will decrease. When the second voltage signal obtained by the reverse signal measurement in the second stage is affected by a conductive substance such as a finger, a voltage rise occurs. Since the signal characteristic of the first stage signal measurement is affected by the conductive material such as the finger is the voltage drop, the second stage signal measurement is affected by the conductive material such as the finger, and the signal characteristic is the voltage, and the noise is measured or reversed by the positive signal. The effect of the signal measurement is to simultaneously increase or simultaneously reduce the signal level. Therefore, when calculating the difference between the first voltage signal and the second voltage signal, not only the touch signal can be obtained twice, but also the noise signal bit is simultaneously The quasi-impact is deducted from it. Since the method of the present invention does not require the base signal to be used as a comparison benchmark for the touch control, and the obtained signal strength is twice that of the prior art, and the noise is applied to the base signal and the noise to the touch signal. The effect is also eliminated during the signal processing, so a more accurate touch signal can be obtained and half of the measurement time can be saved.

110, 21‧‧‧ drive electrodes

120, 22‧‧‧Induction electrodes

130‧‧‧Matrix structure

Y ₁ , Y ₂ ,...Y _n-1 , Y _n ‧‧‧multiple row electrode strips for driving electrodes

X ₁ , X ₂ , ... X _n-1 , X _n ‧‧‧multiple column electrode strips of sensing electrodes

140‧‧‧Control circuit

141‧‧‧Control unit

150‧‧‧Sensor signal receiving module, analog digital signal conversion circuit

160‧‧‧ drive circuit

23‧‧‧Induction electrode line

T1~t11‧‧‧ Timing

Vout, Driver, Sense, Charge‧‧‧ Curve

FIG. 1 is a schematic diagram of a capacitive touch panel implemented by the present invention.

2a to 2e are schematic diagrams showing steps of inducing voltage generation in an embodiment of the present invention.

FIG. 3 is a schematic diagram showing the influence of a conductive material such as a finger approaching or contacting a capacitive touch panel in the step of generating an induced voltage in the embodiment of the present invention.

4 is a timing diagram of an operational flow of a preferred embodiment of the present invention.

5a to 5g are schematic diagrams showing the state of the touch panel of the operation flow in FIG.

6 is a schematic flow chart of a method for recognizing a touch signal according to an embodiment of the present invention; Figure.

The above and other technical contents, features and advantages of the present invention will be apparent from the following detailed description of the preferred embodiments. The directional terms mentioned in the following embodiments, such as upper, lower, left, right, front or rear, etc., are only used to refer to the directions of the accompanying drawings. Therefore, the directional terms are used for illustration only and are not intended to limit the invention.

1 is a schematic diagram of a capacitive touch panel implemented by the present invention, which is composed of a plurality of driving electrodes 110 and a plurality of sensing electrodes 120 (X ₁ , X ₂ , . . . X _n-1 , X _n ) The driving electrode 110 and the sensing electrode 120 are made of a conductive material and form a matrix structure 130 with each other, and the sensing electrode 120 is disposed above the driving electrode 110. The driving electrode 110 is composed of a plurality of row electrode strips (Y ₁ , Y ₂ , ..., Y _n-1 , Y _n ), and the sensing electrode 120 is composed of a plurality of column electrodes (X ₁ , X ₂ , ... X) _N-1 , X _n ). The capacitive touch panel of the matrix structure 130 is electrically connected to a control circuit 140 and has a touch function.

The control circuit 140 has at least one control unit 141, a sensing signal receiving module 150 and a driving circuit 160. The sensing signal receiving module 150 can also be an analog to digital converter (ADC). The control unit 141 is electrically coupled to the driving circuit 160 and the analog digital signal conversion circuit 150. The analog digital signal conversion circuit 150 is connected to the sensing electrode 120. The driving circuit 160 is electrically connected to the driving electrode 110. The capacitive touch panel is configured to apply a power signal to the driving electrode 110 by the driving circuit 160, and form an induced electric field with the sensing electrode 120 to have an induced capacitance and charge the sensing electrode 120 through the sensing capacitor, so that the sensing electrode 120 has an induction. The voltage is received by the analog digital signal conversion circuit 150 and converted into a sensing signal. Judging whether there is a conductive substance such as a finger touching the touch surface by the change of the sensing signal Board and determine the touch location.

In one embodiment, the drive electrodes 110 (Y ₁ , Y ₂ , . . . , Y _n-1 , Y _n ) of each row on the capacitive touch panel of the matrix structure 130 are respectively respectively performed by the analog digital signal conversion circuit 150. Or each column of the sensing electrodes 120 (X ₁ , X ₂ , ... X _n-1 , X _n ) is driven to scan the corresponding sensing electrodes 120 (X ₁ , X ₂ , ... X _{n- 1} , X _n ) or drive electrodes 110 (Y ₁ , Y ₂ , ... Y _n-1 , Y _n ) to receive the voltage signals generated by them; in the row of the capacitive touch panel of the matrix structure 130 ( X ₁ , X ₂ , ... X _n-1 , X _n ) or columns (Y ₁ , Y ₂ , ... Y _n-1 , Y _n ) are scanned one by one or by line by line, Obtain the voltage value of the column or row; or scan two or more columns at a time to obtain multiple voltage values; then process the acquired voltage value data to generate a sensing signal.

Please refer to FIG. 2a to FIG. 2e, which are steps of inducing voltage generation in the embodiment of the present invention. FIG. 2a is a schematic diagram showing one of the pair of capacitive touch panels shown in FIG. 1 with respect to the driving electrode 21 and the sensing electrode 22. 2a shows that the driving electrode 21 is at a low voltage (Driver Low Voltage), and the sensing electrode 22 is electrically coupled to a sensing electrode line 23 to ground (Gnding). At this time, no induced electric field occurs between the driving electrode 21 and the sensing electrode 22.

2b shows that the driving electrode 21 is at a high voltage (Driver High Voltage), and the sensing electrode 22 is still electrically coupled to the sensing electrode line 23 to ground (Gnding), so that the sensing electrode 22 is in a grounded state, and between the driving electrode 21 and the sensing electrode 22 Although an induced electric field occurs, the induced voltage generated is electrically neutralized by the grounding. At this time, the sensing electrode 22 is electrically neutral and does not generate an induced voltage change.

2c shows that the driving electrode 21 is at a high voltage (Driver High Voltage), the sensing electrode 22 is electrically coupled to the sensing electrode line 23, and the sensing electrode line 23 is in a floating state, and between the driving electrode 21 and the sensing electrode 22 at this time. Although an induced electric field occurs, the sensing electrode 22 is still electrically neutral under a stable electric field state.

2d shows that the driving electrode 21 is at a high voltage (Driver High Voltage), the sensing electrode 22 is electrically coupled to the sensing electrode line 23, and the sensing electrode 22 is charged via the sensing electrode line 23 by an analog digital signal conversion circuit; The method can charge the sensing electrode 22 with a fixed amount of current for a fixed time. After the charging is completed, the sensing electrode 22 has a certain amount of electric charge; the charging method is also preset to a voltage level, and is not fixed. The time is charged until the voltage level of the sensing electrode 22 reaches a preset value, that is, charging is stopped; at this time, an induced electric field is maintained between the driving electrode 21 and the sensing electrode 22, and the sensing electrode 22 is maintained at a certain amount in a stable electric field state. The charge.

2e shows that the driving electrode 21 is switched to the driver low voltage, and the sensing electrode 22 is electrically coupled to the sensing electrode line 23; at this time, the negative charge bounded by the induced electric field in the sensing electrode 22 is generated in the step of FIG. 2d. The positive charge generates an electrical neutralization reaction. After the electrical neutralization, the remaining unneutralized positive charge generates a positive voltage at the sensing electrode 22, and the analog electrode line 23 is used to analog digital signal conversion circuit (ADC). Transmitting this voltage signal, and then using the control unit to perform signal interpretation and calculation.

Referring to FIG. 3a to FIG. 3e, in the step of inducing voltage generation in the embodiment of the present invention, the voltage signal is generated by the influence of a conductive material such as a finger approaching or contacting the capacitive touch panel. 3a shows that the driving electrode 21 is at a low voltage (Driver Low Voltage), and the sensing electrode 22 is electrically coupled to the sensing electrode line 23 to ground (Gnding). At this time, no induced electric field occurs between the driving electrode 21 and the sensing electrode 22.

FIG. 3b shows that the driving electrode 21 is at a high potential (Driver Hign Voltage), and the sensing electrode 22 is still electrically coupled to the sensing electrode line 23, and an induced electric field is generated between the driving electrode 21 and the sensing electrode 22, but the induced voltage is generated. Electrically neutralized due to grounding (Gnding) The electrode 22 is still electrically neutral and does not produce an induced voltage change.

3c shows that the driving electrode 21 is at a high potential, the sensing electrode 22 is electrically coupled to the sensing electrode line 23, and the sensing electrode line 23 is in a floating state. At this time, an induced electric field occurs between the driving electrode 21 and the sensing electrode 22, but In the stable electric field state, the sensing electrode 22 is still electrically neutral; due to the proximity or contact of a conductive substance such as a finger, the induced electric field is disturbed, and the induced electric field can only bind less negative charges.

3d shows that the driving electrode 21 is at a high potential, the sensing electrode 22 is electrically coupled to the sensing electrode line 23, and the sensing electrode 22 is charged via the sensing electrode line 23 by an analog digital signal conversion circuit; the charging method can be fixed at a fixed time. The sensing electrode 22 is charged with a fixed amount of current during the time. After the charging is completed, the sensing electrode 22 has a certain amount of electric charge; the charging method is also preset to a voltage level, and is charged to the sensing manner in a fixed time manner. The voltage level of the electrode 22 reaches a preset value to stop charging; at this time, an induced electric field is maintained between the driving electrode 21 and the sensing electrode 22. In the stable electric field state, the sensing electrode 22 maintains a certain amount of electric charge. It is only affected by the charging method and has nothing to do with the induction field.

Figure 3e shows that the drive electrode 21 is switched to a low potential at this time, and the sense electrode 22 is electrically coupled to the sense electrode line 23; at this time, the negative charge in the sense electrode 22 bound by the induced electric field and the positive charge generated in the step of Fig. 3d An electrical neutralization reaction is generated. After the electrical neutralization, the residual positive charge that is not neutralized generates a positive voltage at the sensing electrode 22, and when the conductive material such as a finger approaches or contacts the surface of the touch panel, The amount of negative charge that can be restrained by the place is small, so the positive voltage is greater than the positive voltage generated in the step of FIG. 3e, and the voltage signal is transmitted to the analog digital signal conversion circuit by the sensing electrode line 23, and then the signal is read by the control unit. The AND operation can determine that a touch event has occurred.

The control unit of FIG. 1 interprets and calculates the voltage signal generated by the steps of FIG. 3a to FIG. 3e. When the voltage signal exceeds a threshold value, it is determined that a touch event occurs, and after the operation, The host transmits the address signal of the touch. The foregoing method is performed by the control unit for sequentially driving the driving electrodes Y ₁ , Y ₂ ... Y _n-1 , Y _n of each row and the sensing electrodes X ₁ , X ₂ ... X _n-1 , X _{n of} each column. The instructions for performing the aforementioned steps of Figures 2a to 2e or 3a to 3e are issued.

The process sequence of the preferred embodiment of the present invention is shown in FIG. 4, together with the schematic diagram of the capacitive touch panel of FIG. 1 and the state of the touch panel of the operation steps shown in FIGS. 5a to 5g. The curve Vout represents the voltage signal change received by the analog digital signal conversion circuit 150; the curve Driver represents the change of the driving signal voltage, and the driving circuit 160 receives the instruction of the control element 141 to perform the reference potential on the driving electrode 110 at a predetermined timing (also That is, the low potential LOW) is switched with the reference potential (ie, the high potential High); the curve Sense indicates the state switching of the sensing electrode 120, and the analog digital signal conversion circuit 150 accepts the instruction of the control element 141 to switch the sensing electrode at a preset timing. In the electrical coupling state of 120, the sensing electrodes are respectively coupled to the ground (GND) and the floating end (Flow), and are in a grounded state or a floating state; the curve Charge is an analog digital signal conversion circuit 150 charging the sensing electrode 120. State, respectively, the charging state is turned on (ON) or turned off (OFF).

Timing t1-t2: The analog digital signal conversion circuit 150 switches the sensing electrode 120 from the ground state to the floating state. The state of the reference touch panel is as shown in FIG. 5a, and the timing t1 is the initial state of the present invention. At this time, the driving circuit 160 electrically couples the driving electrode 110 to the reference potential (ie, the low potential LOW), and the sensing electrode 110 is electrically connected. When coupled to the ground and in a grounded state, the analog digital signal conversion circuit 150 is switched to the off state. The state of the reference touch panel is as shown in FIG. 5b, and the timing t2 is a ready state. At this time, the driving circuit 160 still electrically couples the driving electrode 110 to the reference potential. (ie, low potential LOW), the sensing electrode 110 is electrically coupled to the floating terminal and switched to the floating state, and the analog digital signal conversion circuit 150 is still in the off state (OFF).

Timing t3: The driving electrode 110 is charged to a reference potential (ie, high potential High) while the sensing electrode 120 is in a floating state. The state of the reference touch panel is as shown in FIG. 5c. The timing t3 is the startup state of the first measurement cycle. At this time, the driving circuit 160 electrically couples the driving electrode 110 to the reference potential (High), and the sensing electrode 110 remains electrically. The analog digital signal conversion circuit 150 is still in a closed state. In the closed state, the driving electrode 110 starts to generate an induced electric field with the sensing electrode 120 to cause a potential change of the sensing electrode, and analog digital signal conversion Circuit 150 produces a voltage change as indicated by curve Vout

Timing t4: The sensing electrode 120 is measured by the analog digital signal conversion circuit 150 to generate a first voltage signal V ₂₁ . The analog digital signal conversion circuit 150 performs the first signal sampling after the timing t4, that is, after the induced voltage is stabilized, to avoid obtaining an unstable voltage signal, and obtaining the first voltage signal V ₂₁ .

Timing t5: The switching sensing electrode 120 is restored from the floating state to the grounded state. Referring to the state of the reference touch panel, as shown in FIG. 5d, at time t5, the sensing electrode 110 is electrically coupled to the ground, which is prepared for the second measurement cycle, and the charge stored in the sensing electrode 120 is grounded. In the neutralization, the signal of the analog digital signal conversion circuit 150 returns to the reference potential.

Timing t6: The drive electrode is kept charged to a high potential. The state of the reference touch panel is as shown in FIG. 5e, which is the startup state of the second measurement cycle. At this time, the driving circuit still electrically couples the driving electrode 110 to the reference potential (ie, high potential), and the sensing electrode 110 switches. Coupled to the floating terminal, the analog digital signal conversion circuit 150 is still in a closed state, in which the driving electrode 110 starts to generate an induced electric field with the sensing electrode 120, but does not cause a potential change of the sensing electrode, such as As shown by the curve Sense in Fig. 5, the sensing electrode 120 is still at the reference potential (i.e., grounded state).

Timing t7-t9: At the same time, the sensing electrode 120 is switched from the ground state to the floating state; then, the sensing electrode 120 is charged by the analog digital signal conversion circuit; then, the sensing electrode 120 is stopped, so that the driving electrode 110 is high. It drops to a low level while the sensing electrode is still in a floating state. Referring to the state of the reference touch panel, as shown in FIG. 5f, at the timing t7-t8, the analog digital signal conversion circuit 150 switches to the on state (ON) and then switches to the off state (OFF), and the sensing electrode 120 maintains electrical coupling to the floating state. At the same time, the sensing electrode 120 begins to store charge to generate a voltage change indicated by the curve Sense. The voltage change is independent of the reference voltage of the driving circuit and is only related to the amount of charge charged by the analog digital signal conversion circuit 150. As for the timing t9, the state of the reference touch panel is as shown in FIG. 5g. At this time, the driving circuit 160 electrically couples the driving electrode 110 to the reference potential (ie, the low potential LOW), and the sensing electrode 110 remains electrically coupled to the floating connection. The analog digital signal conversion circuit 150 is switched to the off state. In this state, since the induced electric field disappears, the amount of induced charge bound by it is electrically neutralized with the charge stored in the previous step, resulting in a sensing electrode. The potential drops, and the analog digital signal conversion circuit 150 is as shown by the curve Sense, and the received voltage drops.

Timing t10: After the electrical neutralization reaction is stabilized, the second signal sampling of the sensing electrode is performed by the analog digital signal conversion circuit to obtain the second voltage signal V ₂₂ .

Timing t11: Finally, the difference between the first voltage signal V ₂₁ and the second voltage signal V ₂₂ is calculated to obtain a sensing signal. The sensing electrode 110 is switched electrically coupled to the ground to enter the measurement cycle preparation state of the next stage. The difference between the average voltage value of the first voltage signal and the average voltage value of the second voltage sensing signal is defined as a base signal.

When a conductive material such as a finger or other pointing object approaches or touches the touch panel, the sensing signal is obtained as a substrate signal S _2B ; when a conductive substance such as a finger or other pointing object approaches or touches the touch panel, The sensing signal is a contact signal S _2F . Next, calculate the difference signal S _2F and the contact signal S _2B of the substrate, i.e. the contact base signal by subtracting the signal S _2F S _2B, to obtain a more accurate of the touch signal S _2T. Since the signal characteristic of the first voltage signal affected by the conductive material such as the finger is a voltage drop, the signal characteristic of the second voltage signal affected by the conductive material such as the finger is a voltage rise; but the influence of the noise on the first or second measurement cycle is In order to simultaneously increase or reduce the voltage signal at the same time, the second voltage signal V ₂₂ minus the first voltage signal V ₂₁ can not only obtain twice the touch signal, but also deduct the influence of the noise from the signal.

In addition, the method of the present invention does not need to obtain the base signal as a comparison benchmark for the touch when each measurement is performed, and the obtained signal intensity is twice that of the prior art, and the noise is contacted by the base signal S _2B and the noise pair. The effect of the signal S _2F is also eliminated during the signal processing, so that the more accurate touch signal S _2T can be obtained and half of the measurement time can be saved.

FIG. 6 is a schematic flowchart diagram of a method for recognizing a touch signal according to an embodiment of the present invention. The embodiment of the invention achieves the purpose of enhancing the signal and reducing the noise by utilizing the difference in the characteristics of the touch signal.

First, after the device system for recognizing the touch signal is initialized, step S101 is performed to perform the forward signal measurement of the first measurement cycle to obtain the first voltage signal. If the conductive material is affected by the finger or the like at this stage, The signal characteristics will show a voltage drop. Next, in step S102, the reverse signal measurement of the second measurement cycle is performed to obtain the second voltage signal. If the conductive material is affected by a finger or the like at this stage, the signal characteristic will increase. Then, in step S103, the first voltage signal and the second voltage signal are subjected to signal differential processing to obtain a more accurate touch signal S _T . Since the influence of noise on the forward signal measurement or the reverse signal measurement is simultaneously increasing or simultaneously reducing the signal level, the difference between the first voltage signal and the second voltage signal can be obtained not only twice as much. The control signal, and at the same time, the effect of noise on the signal level is deducted.

Then, in step S104, a control unit is used to compare the voltage value of the touch signal S _T with a threshold value. When the voltage value of the touch signal S _T is less than or equal to the threshold value, step S105 is performed, and the control unit outputs the touch signal S _T ; when the voltage value of the touch signal S _T is greater than the threshold value, step S106 is performed to control The unit does not act on the touch signal. The sensing electrode is switched electrically coupled to the ground to enter the initialization state of the measurement cycle of the next stage.

The above is only the preferred embodiment of the present invention, and the scope of the invention is not limited thereto, that is, the simple equivalent changes and modifications made by the scope of the invention and the description of the invention are All remain within the scope of the invention patent. In addition, any of the objects or advantages or features of the present invention are not required to be achieved by any embodiment or application of the invention. In addition, the abstract sections and headings are only used to assist in the search of patent documents and are not intended to limit the scope of the invention.

Claims (18)

A method for recognizing a touch signal is applied to a touch panel, the method comprising: providing at least one driving electrode and at least one sensing electrode; switching the sensing electrode from a ground state to a floating state; and driving the driving electrode Charging to a high potential while the sensing electrode is in the floating state; measuring the sensing electrode by an analog-digital signal conversion circuit to generate a first voltage signal; switching the sensing electrode from the floating state Returning to the ground state; maintaining the driving electrode at the high potential while switching the sensing electrode from the ground state to the floating state; charging the sensing electrode by using the analog digital signal conversion circuit; stopping the sensing electrode Charging, the driving electrode is lowered from the high potential to a low potential, and the sensing electrode is still in the floating state; the analog electrode is measured by the analog digital signal conversion circuit to generate a second voltage And calculating a difference between the first voltage signal and the second voltage signal to obtain a sensing signal. The method for recognizing a touch signal according to claim 1, wherein the sensing signal is defined as a base signal if no pointing object contacts the touch panel. The method for recognizing a touch signal according to claim 1, wherein the plurality of driving electrodes are plural, and the plurality of sensing electrodes are plural, and the analog digital signal conversion circuit sequentially processes the plurality of signals. The sensing electrodes are measured to generate a plurality of first voltage signals and a plurality of second voltage signals, and the difference between the average voltage value of the first voltage signals and the average voltage values of the second voltage sensing signals, It is defined as a base signal. The method for recognizing a touch signal according to the second or third aspect of the patent application, wherein if the pointing object contacts the touch panel, the sensing signal is defined as a contact signal, and the method further comprises calculating the contact The difference between the signal and the base signal to generate a touch signal. The method for generating a touch signal according to the method of claim 4, wherein the step of generating the touch signal further comprises: comparing, by a control unit, a voltage value and a threshold value of the touch signal; When the voltage value of the touch signal is less than or equal to the threshold value, the control unit outputs the touch signal. The method for recognizing a touch signal as described in claim 5, wherein the control unit does not operate on the touch signal when the voltage value of the touch signal is greater than a threshold value. An apparatus for recognizing a touch signal includes: at least one driving electrode; a driving circuit electrically connected to the driving electrode; at least one sensing electrode disposed above the driving electrode; and an analog-digital signal conversion circuit Connecting the sensing electrode; and a control unit electrically coupling the driving circuit and the analog digital signal conversion circuit; The control unit switches the sensing electrode from a ground state to a floating state, and then the driving circuit charges the driving electrode to a high potential; and the analog electrode is measured by the analog digital signal conversion circuit a control unit that switches the sensing electrode to return to the ground state; the driving circuit maintains the driving electrode at the high potential, and the control unit switches the sensing electrode by Grounding state to the floating state; charging the sensing electrode by using the analog digital signal conversion circuit; stopping charging the sensing electrode, so that the driving electrode is lowered from the high potential to a low potential, and the sensing electrode is still located at the a floating state; the analog electrode is measured by the analog digital signal conversion circuit to generate a second voltage signal; and the control unit calculates a difference between the first voltage signal and the second voltage signal, To get a sensing signal. The device for recognizing a touch signal according to claim 7, wherein the sensing signal is defined as a base signal if no pointing object contacts the touch panel. The device for recognizing a touch signal according to the seventh aspect of the invention, wherein the plurality of driving electrodes are plural, and the plurality of sensing electrodes are plural, and the sensing electrodes are sequentially measured by the analog digital signal conversion circuit. And generating a plurality of first voltage signals and a plurality of second voltage signals, and the difference between the average voltage value of the first voltage signals and the average voltage value of the second voltage sensing signals is defined as one Base signal. The device for recognizing a touch signal as described in claim 8 or 9, wherein if the pointing object contacts the touch panel, the sensing signal is defined as a contact signal, and the contact signal and the base signal are The difference is defined as a touch signal. The device for recognizing a touch signal according to claim 10, wherein the control unit is configured to compare a voltage value of the touch signal with a threshold value, and when the voltage value of the touch signal is less than or equal to the threshold The limit unit sends the touch signal to the control unit. The device for recognizing a touch signal according to claim 10, wherein the control unit is configured to compare a voltage value of the touch signal with a threshold value, and when the voltage value of the touch signal is greater than the threshold value The control unit does not operate on the touch signal. A method for recognizing a touch signal is applied to a touch panel, the method comprising: performing initialization; performing a first measurement cycle to obtain a first voltage signal; performing a second measurement cycle, And obtaining a second voltage signal; and performing a signal differential processing according to the first voltage signal and the second voltage signal to generate a touch signal. The method for generating a touch signal according to the method of claim 13 wherein the step of generating the touch signal further comprises: comparing a voltage value of the touch signal with a threshold value by a control unit; When the voltage value of the touch signal is less than or equal to the threshold value, the control unit outputs the touch signal. The method for recognizing a touch signal according to claim 14, wherein the control unit does not operate the touch signal when the voltage value of the touch signal is greater than a threshold value. The method for recognizing a touch signal as described in claim 13 further includes, after performing the second measurement cycle, re-initializing to repeat the first measurement cycle and the second amount The measurement cycle obtains a plurality of first voltage signals and a plurality of second voltage signals. The method for recognizing a touch signal according to claim 13 , wherein the first measurement cycle is at least one positive vector measurement cycle, and the second measurement cycle is at least one inverse vector measurement cycle. The method for recognizing a touch signal according to claim 13 , wherein the first measurement cycle is at least one inverse vector measurement cycle, and the second measurement cycle is at least one positive vector measurement cycle.