CN110739953A

CN110739953A - Scene type signal self-adaptive processing method of capacitive touch keys and electronic device

Info

Publication number: CN110739953A
Application number: CN201910993494.0A
Authority: CN
Inventors: 周留洋
Original assignee: Sichuan Zhongwei Core Cheng Technology Co Ltd
Current assignee: Sichuan Zhongwei Core Cheng Technology Co Ltd
Priority date: 2019-10-18
Filing date: 2019-10-18
Publication date: 2020-01-31
Anticipated expiration: 2039-10-18
Also published as: CN110739953B

Abstract

The invention provides a scene type signal self-adaptive processing method of capacitive touch keys and an electronic device.

Description

Scene type signal self-adaptive processing method of capacitive touch keys and electronic device

Technical Field

The invention relates to the field of signal processing and control, in particular to a scene type signal self-adaptive processing method of capacitive touch keys and an electronic device.

Background

With the increasing popularity of the capacitive touch keys in electronic products such as household appliances, more and more users operate the electronic products through the capacitive touch keys to enjoy the convenience brought by the capacitive touch keys for life. Meanwhile, the capacitive touch key has the advantages of being inherently friendly to operation, novel in interface and the like, and is rapidly replacing the traditional key, so that the capacitive touch key becomes the mainstream of the market.

However, due to the universality of the usage scenario of the electronic product, such as different altitudes, different air pressures, different environmental temperatures, different environmental humidities, different regional environments, etc., the capacitive touch key is easily affected by various influences due to the characteristics of the capacitor itself, resulting in unstable capacitive signals.

Wherein:

ε₀dielectric constant of air

ε_rRelative dielectric constant of the coating

A ═ contact area of finger with sensor pad overlay

Thickness of covering layer

C_FIs the finger capacitance.

Changes in the touch environment, such as temperature, humidity, etc., will cause the capacitance signal to drift slowly and slightly but continuously as the environment changes; e.g., cleanliness of the touch surface (e.g., water drops, oil stain), will cause the capacitance signal to suddenly shift up or down, and then stay on; for example, the ripple of a single source of the system will make the capacitance signal fluctuate with ripple fluctuation; for example, noise and interference (such as radio frequency signals of a mobile phone and electromagnetic signals of a microwave oven) brought by other devices in the surrounding environment can cause the capacitance signal to change rapidly and violently due to the interference; even the thermal noise caused by the chip manufacturing process can cause the capacitance signal to rapidly shake up and down with small amplitude.

In the operation process of the capacitive touch keys, the detection unit stores an untouched capacitance value (reference value) for every touch keys, and when the latest capacitance value (sensing value) is subsequently received, the received sensing value is compared with the corresponding judgment reference value to judge whether the key is touched.

In the prior art, for example, some of the existing technologies use AD sampling to detect the jitter of the power supply ripple, and use different processing modes according to the jitter, for example, some of the existing technologies use a dedicated interference detection circuit to detect the occurrence of interference, so that the detection of touch can avoid the interference in time. The above-mentioned techniques have problems that, for example, adding an external interference detection circuit means increasing the cost, and indirectly analyzing a relevant interference signal without directly analyzing a capacitance signal itself, which results in imperfect analysis and processing of the signal, and finally results in misjudgment of whether a key is touched.

Disclosure of Invention

In order to solve the deficiencies of the prior art mentioned in the background art, the invention provides a scene type signal adaptive processing method of types of capacitive touch keys and an electronic device.

, the invention provides methods for adaptively processing signals of capacitive touch keys.

The method comprises the steps of collecting touch key signals to obtain a current signal sensing value which is the number of pulses within time, classifying signal scenes according to the change rate, the change intensity and the change duration of the sensing value to determine a current signal scene, storing the current signal scene, comparing the current signal scene with the last signal scene to determine whether the scene changes, using a signal processing mode of the same scene if the signal scene does not change, switching the scene if the signal scene changes, using a signal processing mode of a new scene, and processing key signals according to the signal processing mode.

Further , the acquisition of the touch key signal can employ relaxation oscillation frequency measurement or charge transfer measurement based detection of the touch signal.

Preferably, after the touch key signal is acquired, the signal may be further preprocessed, where the preprocessing is specifically two-stage processing, the th stage processing is sliding window dynamic tracking filtering, and the second stage processing is inertial filtering.

The sliding window dynamic tracking filtering can be realized by regarding continuously acquired N sensing values as queues, fixing the length of the queues to be N, and performing arithmetic mean operation on N data in the queues by adopting a first-in first-out principle to obtain a new filtering result.

implementations of inertial filtering may be such that filtering is performed using the following equation

The filtering result of this time is (1-a) + a value of this time signal and the last filtering result

Wherein, the value range of a is between 0 and 1.

Preferably, the change rate, the change intensity and the change duration are implemented by continuously acquiring sensing values, recording the ith sensing value as Data [ i ], measuring the sensing change quantity [ sigma [ i ] ═ Data [ i ] -Data [ i-1] the ith, accumulating the sensing change quantity [ sigma ] to [ sigma ], and initializing the [ sigma ] to 0 until the i reaches the preset maximum acquisition time or the absolute value of the [ sigma ] is smaller than the preset th threshold, wherein the change rate is sigma/N, the change intensity is the absolute value of the [ sigma ], and the change duration is i multiplied by the single acquisition time.

Preferably, the signal scene classification according to the change rate, the change intensity and the change duration of the sensing values comprises at least scenes as follows:

signal scene, the change rate is negative, the change intensity is less than the lower noise line, the duration is signal scene time T1;

second signal scenario: the change rate is positive, the change intensity is smaller than the upper noise line, and the duration is the second signal scene time T2;

third signal scenario: the sensing value shakes up and down in the range of the upper noise line and the lower noise line;

fourth signal scenario: the change rate is positive, the change intensity is greater than the upper noise line and less than the maximum signal line, and the duration is the fourth signal scene time T4;

fifth signal scenario: the change rate is positive, the change intensity is greater than the maximum signal line, and the duration is the fifth signal scene time T5;

sixth signal scenario: the rate of change is negative, the intensity of change is greater than the lower noise line and less than the touch line, and the duration is the sixth signal scene time T6;

seventh signal scenario: the rate of change is negative, the strength of change is greater than the touch line and less than the minimum signal line, and the duration is a seventh signal scene time T7;

eighth signal scenario: the change rate is negative, the change intensity is greater than the minimum signal line, and the duration is the eighth signal scene time T8;

wherein minimum signal line < lower noise line < touch line < reference line < upper noise line < maximum signal line;

the touch line is a threshold line for judging that the key is touched under an ideal condition;

the reference line is determined by the sensing value when the key is ideally not touched.

It should be noted that, for different products, the above scenes may appear simultaneously, or only some of them may be selected.

The signal processing method using the new scene comprises the following steps:

when the current scene is determined to be the th signal scene, the reference line is the th signal scene constant, and the th scene constant takes off the difference value between the noise line and the reference line by 0.2 times to 0.5 times;

when the current scene is determined to be a second signal scene, the reference line is the reference line plus a second signal scene constant, and the second signal scene constant takes the difference value between the noise line and the reference line from 0.3 times to 0.6 times;

when the current scene is determined to be the third signal scene, the reference line is the reference line;

when the current scene is determined to be a fourth signal scene, the reference line is equal to the reference line and a fourth signal scene constant, and the fourth signal scene constant is between 0.2 times and 0.5 times of the difference value of the sensing line and the reference line;

when the current scene is determined to be a fifth signal scene, the reference line is equal to the reference line and a fifth signal scene constant, and the fifth signal scene constant is between 0.6 times and 0.8 times of the difference value of the sensing line and the reference line;

when the current scene is determined to be a sixth signal scene, the reference line is equal to a reference line-sixth signal scene constant, and the sixth signal scene constant is between 0.6 times and 0.8 times of the difference value of the sensing line and the reference line;

when the current scene is determined to be the seventh signal scene, testing touch generation without adjusting the reference line;

when it is determined that the current scene is the eighth signal scene, the reference line is the sensing line, which is determined by the sensing value.

The above-described processing methods are not necessarily all required of , and may be selectively combined and used according to the demand of the product.

Further , after the reference line is re-determined, the minimum signal line, the lower noise line, the touch line, the upper noise line, and the maximum signal line are re-determined based on the difference or ratio of the original minimum signal line, the original lower noise line, the original touch line, the original upper noise line, the original maximum signal line, and the original reference line.

, the key signal processing according to the signal processing mode can be that the key is determined to be pressed when the sensing value is greater than the touch line within time, otherwise, the key is determined not to be pressed.

, the invention also provides electronic devices, which comprise or more touch switches, a touch detection unit, a signal scene classification unit, a signal scene storage unit, a scene comparison unit, a scene processing unit, an inter-scene processing unit and a key information judgment unit, wherein,

the touch detection unit is used for collecting touch key signals to obtain current signal sensing values, wherein the sensing values are pulses within a certain time;

the signal scene classification unit is used for classifying signal scenes according to the change rate, the change intensity and the change duration of the sensing values and determining the current signal scene;

a signal scene storage unit for storing a current signal scene;

the scene comparison unit is used for comparing the current signal scene with the last signal scene and determining whether the scene changes;

a scene processing unit, for using the signal processing mode of the same scene if the signal scene has no change;

the scene processing unit is used for switching scenes if the signal scene changes and using a signal processing mode of a new scene;

and the key information judgment unit is used for carrying out key signal processing according to the signal processing mode.

According to the scene type signal self-adaptive processing method, the touch electronic device can carry out all-around analysis and processing on the signal through the analysis of each scene of the signal and the switching processing of the signal scene, so that the signal self-adaptive processing in the current signal scene and the self-adaptive switching and processing among the signal scenes are realized, and the self-adaptation of the key touch judgment information in various signal scenes is ensured.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings based on the drawings without creative efforts.

FIG. 1 is a schematic diagram of a touch circuit based on an RC (relaxation oscillation frequency) measurement method;

FIG. 2 is a schematic diagram of a touch signal based on an RC (relaxation oscillation frequency) measurement method;

FIG. 3 is a schematic diagram of touch data based on an RC (relaxation oscillation frequency) measurement method;

FIG. 4 is a schematic diagram of a touch circuit based on a charge transfer measurement method;

FIG. 5 is a schematic diagram of a touch signal based on a charge transfer measurement method;

FIG. 6 is a schematic diagram of touch data based on a charge transfer measurement method;

FIG. 7 is a block diagram of a signal adaptive touch switch system and electronics;

FIG. 8 illustrates embodiments of a touch detection controller based on an RC (relaxation oscillation frequency) measurement method;

FIG. 9 illustrates embodiments of a touch detection controller based on a charge transfer measurement method;

FIG. 10 is a schematic diagram of a signal preprocessor;

FIG. 11 is a schematic view of a reference line variation;

FIG. 12 is a scene classification flow diagram;

FIG. 13 is a schematic diagram of signal scene classification;

fig. 14 signal scene transition diagram.

Detailed Description

The present invention is described in further detail with reference to the drawings and the detailed description, it should be noted that the embodiment described is part of the embodiment of the present invention, but not all embodiments, and all other embodiments obtained by those skilled in the art without inventive faculty based on the embodiments of the present invention are within the scope of the present invention.

The measurement method of the capacitive touch key signal mainly comprises an RC-based measurement method and a charge transmission-based measurement method, wherein the RC-based measurement method can adopt a relaxation oscillation frequency measurement method, the charge transmission-based measurement method can adopt a charge transmission capacitive sensing technology, the main principle is that capacitance change caused by human finger touch is converted into changes of numerical values such as current, voltage, frequency and time, and the numerical values are increased or decreased possibly caused by the human finger touch according to a specific implementation mode.

The basic principle of the above-described touch signal per measurement method is explained in turn.

(1) RC-based measuring method relaxation oscillation frequency measuring method

The fundamental principle of "Relaxation oscillation" (Relaxation 0 oscillator) touch detection is Relaxation oscillators that are constantly charged and discharged, as shown in fig. 1, touch detection circuit diagrams constructed based on the principle of "Relaxation oscillation" are such that if an electrode is not touched, the Relaxation oscillator has fixed fundamental charge and discharge cycles (frequencies) that are equivalent to the parasitic capacitance Cp and the resistance R, if an electrode is touched with a finger, an electric field effect is generated between the finger and the electrode, the finger capacitance Cf is superimposed on the original parasitic capacitance Cp of the key, the charge and discharge cycles of the Relaxation oscillator become longer, and the frequency is correspondingly reduced, as shown in fig. 1, touch detection circuit diagrams constructed based on the principle of "Relaxation oscillation", wherein the parasitic capacitance Cp is the capacitance when the key is touched, when the positive terminal voltage of the comparator is higher than the negative terminal voltage of the comparator, the VOUT output is a high voltage, when the comparator output is higher than the positive terminal voltage Vref, the comparator output is higher than the positive terminal voltage of the rectangular capacitor when the voltage of the rectangular capacitor is higher than the positive terminal voltage of the rectangular capacitor, the capacitor VOUT output voltage is higher than the positive terminal voltage of the rectangular capacitor, when the voltage of the capacitor VOUT is higher than the positive terminal voltage of the positive terminal, the capacitor VOUT, the capacitor output voltage of the capacitor is higher than the voltage of the positive terminal, the capacitor is higher voltage of the capacitor, and the capacitor is higher than the voltage of the capacitor, when the voltage of the capacitor, the capacitor is higher voltage of the capacitor, the capacitor is.

As shown in fig. 2, if measurement time periods t1 are determined using the reference clock and the oscillator output frequency is counted in the measurement time period t1, a touch event can be detected, as shown in fig. 2, the count value at the time of touch is less than the count value at the time of non-touch in the same measurement time period, and if the reference clock is clocked when the oscillator outputs the same number of pulses, as shown in fig. 2, the count value t1 at the time of touch is greater than the count value t0 at the time of non-touch in the same number of pulses.

As shown in fig. 3, in the measurement mode in which measurement time periods are determined using the reference clock and the oscillator output frequency is counted in the measurement time periods, it can be seen that the touch data grows downward when the count value at the time of touch is smaller than the count value at the time of non-touch, and if the reference clock is clocked when the oscillator outputs the same number of pulses, it can be seen that the touch data grows upward when the count value at the time of touch is greater than the count value at the time of non-touch.

(2) Charge transfer-based measurement method charge transfer capacitance sensing technology

The basic principle of the charge transfer capacitance sensing technology can be illustrated by referring to fig. 4, if the electrode is not touched, Cp represents the parasitic capacitance of the capacitance touch electrode, firstly closing the switch K1 to charge the parasitic capacitance Cp, when the parasitic capacitance Cp is fully charged, opening the switch K1, closing the switch K2 to transfer the charge between the parasitic capacitance Cp and the detection capacitance Cs, and charging the detection capacitance Cs, repeating the above charging and charge transfer actions, the voltage of the upper plate V of the detection capacitance Cs gradually rises, when the voltage of the V point rises to Vref, charging cycles of the detection capacitance Cs end, if the electrode is touched by a finger, an electric field effect is generated between the finger and the electrode to parasitize the finger capacitance Cf, the finger capacitance Cf is superposed with the original parasitic capacitance Cp of the key, after the switch K1 charges the parasitic capacitance Cp and the finger capacitance Cf, the charges accumulated by the parasitic capacitance Cp and the capacitance Cf are more increased, and the charges are transferred faster when the parasitic capacitance Cp and the finger capacitance Cf are transferred to the detection capacitance Cs, and the charge transfer frequency is increased accordingly.

Fig. 5 shows a waveform diagram of the V-point voltage in the whole charging cycle, if measurement time periods t2 are determined using the reference clock, and the comparator output frequency (number of pulses) is counted in the measurement time period t2, then a touch event can be detected, as shown in fig. 5, the count value (number of pulses) at the time of touch is greater than the count value (number of pulses) at the time of non-touch in the same measurement time period t2, and if the reference clock is clocked at the time of comparator outputting the same number of pulses, a touch event can also be detected, as shown in fig. 5, the count value t0 at the time of touch is less than the count value t1 at the time of non-touch in the same number of pulses.

As shown in fig. 6, in the measurement mode in which measurement time periods are determined using the reference clock and the comparator output frequency (number of pulses) is counted in the measurement time periods, it can be seen that the touch data grows upward when the count value at the time of touch is greater than the count value at the time of non-touch, and if the reference clock is clocked while the comparator outputs the same number of pulses, it can be seen that the touch data grows downward when the count value at the time of touch is less than the count value at the time of non-touch.

As described above, regardless of the RC-based frequency measurement method or the charge-based transmission measurement method, the capacitance change caused by the touch of the human finger can be finally converted into a change corresponding to the touch data, which can grow upwards or upwards, and , when modes are selected, the growth direction is fixed, that is, the data is either reduced or increased during the touch.

As shown in fig. 7, which is a flowchart of an scene-based signal adaptive touch switch information processing method, firstly, a touch detection controller collects a touch key signal to obtain a current signal sensing value, where the sensing value is the number of pulses within time;

then, preprocessing the acquired signal by using a signal preprocessor;

then, using a signal scene classifier to classify the signal scene according to the change rate, the change intensity and the change duration of the sensing value, and determining the current signal scene;

then using a signal scene memory to store the current signal scene;

after storing the current signal scene, comparing the current signal scene with the last signal scene by using a scene comparator to determine whether the scene is changed;

if the signal scene has no change, using a scene processor to process the signal of the same scene;

if the signal scene is changed, the scene is switched, and an inter-scene processor is used for switching to a new scene and carrying out signal processing;

and finally, performing key signal processing by using a key information judger according to the signal processing mode.

It should be noted that the signal preprocessor is not necessary, and whether to use the preprocessor may be determined according to the requirement for accuracy.

The touch detection unit comprises N touch detection channels, each touch detection channel is provided with a corresponding touch detection element, and the touch detection elements can be electrodes, springs, bonding pads or other similar devices capable of realizing touch detection;

a touch detection controller: the touch detection controller, whether it be an RC-based frequency measurement method or a charge-based transfer measurement method, may be implemented differently, but its primary functions are substantially the same.

In an embodiment of the touch detection controller based on the RC (relaxation oscillation frequency) measurement method as shown in fig. 8, the touch channel is switched by an analog switch, the touch oscillator, see fig. 1, is a touch circuit diagram based on the RC (relaxation oscillation frequency) measurement method for controlling charging and discharging of the touch detection element, detecting the change of the oscillation frequency, analog filtering is used for filtering unstable signals of the oscillation frequency, reference division voltage can be provided to different negative comparison voltages of the comparator, such as 0.4 power voltage, 0.5 power voltage, 0.6 power voltage and 0.7 power voltage, the Comparator (COMP) converts the voltage change on the detection capacitor into pulse waveform output, the pulse waveform is filtered out by digital filtering to be fed into a touch counter for counting, the time slot counter generates a counting interval for use by the touch counter, the time slot clock can be provided by a TKOSC (touch clock) or fsyssys system clock, the clock is provided by a prescaler (SLE _ clock), the clock is provided by a frequency divider (SLE _ prescaler) and the clock, and the clock is provided by a frequency divider (fsc) for frequency divider system for frequency divider (fsc) or frequency divider 362, and frequency divider (fsc) for selecting the touch detector for frequency divider system.

In an embodiment of the touch detection controller based on charge transfer measurement as shown in fig. 9, the touch channel is switched by analog switches, the capacitance charge conversion is shown in fig. 4, which is a schematic diagram of a touch circuit based on charge transfer measurement, and is used to control charging and discharging of the touch detection element, the detection capacitor is used to collect charges, the analog filtering is used to filter unstable charges on the detection capacitor, the reference divided voltage can be provided to different negative comparison voltages of the comparator, such as 0.4 power voltage, 0.5 power voltage, 0.6 power voltage, 0.7 power voltage, the Comparator (COMP) converts the voltage change on the detection capacitor into a pulse waveform output, and the pulse waveform output is filtered by digital filtering to count the pulse waveform, and the pulse waveform is fed to the touch counter, the time slot counter generates a count interval for the touch counter, the clock of the time slot counter can be provided by a TKOSC (touch clock) or Fsys system clock, and the clock can be selected by a TKOSC _ SLE (clock selector) or a frequency divider system (fssy) after being pre-divided by the touch clock (clock) and frequency divider (fssy) of the touch clock) and frequency divider system (fssy system) for frequency division, fssy 2, fsc 52, fssy system.

As shown in the schematic diagram of the signal preprocessor in FIG. 10, the signal preprocessor is used to perform pre-processing on the signal, which may be implemented in two stages, wherein the th stage processing is sliding window dynamic tracking filtering, the second stage processing is inertial filtering, the st stage processing is used to filter out periodic interference data, the st stage processing is used to filter out periodic and non-periodic impulse interference data, the st stage processing result is output as the input of the second stage processing, and the second stage processing result is output as the input of the signal scene classifier.

The sliding window dynamic tracking method is realized by considering continuously acquired N sensing values as queues, fixing the length of the queues to be N, sampling new data each time, putting the new data into the tail of the queue, throwing away data of the original queue first time, namely a first-in first-out principle, performing arithmetic average operation on the N data in the queues to obtain a new filtering result, selecting 1 as 2-16 for the N value, embodiments, and taking the value of N as 5.

The inertial filtering is also called order low-pass filtering or order lag filtering, and the formula is that the filtering Result of this time is (1-a) × the sampling value + a of this time and the filtering Result of last time, wherein the value range of a is between 0 and 1, that is, Result N is (1-a) × TouchDataMean + a × Result N-1, Result N is the filtering Result of the current data, TouchDataMean is the value of the current sampling value after being processed through the th stage, Result N is the filtering Result a of the current data and can be 0.8, and Result N-1 is the filtering Result of last time.

The touch data after signal preprocessing has higher reliability, and the use of a subsequent signal scene classifier is facilitated. As mentioned above, the capacitance change caused by the touch of the human finger may be converted into a change of the touch data, which may be grown upwards or upwards, for convenience, the following explains the downwards growth as an example, and the upwards growth is similar to the downwards growth and can be obtained by simple transformation according to the example herein, and thus, the present invention is also within the protection scope of the present invention.

As shown in the reference line variation diagram of fig. 11, when there is no finger touch and no environmental interference, the signal value in an ideal environment may also be referred to as a reference value, a curve drawn by the reference value with time is referred to as a reference line, and the reference value and the reference line are kept unchanged when the finger touches; the real-time signal values of the touch and the non-touch of the finger are called sensing values, and a curve of the sensing values plotted along with time is called a sensing line.

Theoretically, when no finger touches, a sensing line is smooth straight lines, when a finger touches, the signal grows downwards, if the sensing value when the finger touches is subtracted from the reference value when the finger does not touch, difference values are generated, and when the difference value is large enough, the sensing line is considered to be the finger touch.

Due to the universality of the use scene of the electronic product, such as different altitudes, different air pressures, different environmental temperatures, different environmental humidities, different regional environments and the like, and due to the characteristics of the capacitor, the capacitive touch key is extremely easy to be affected by various influences, so that the reference line is unstable.

Changes in the touch environment, such as temperature, humidity, etc., will cause the reference line to drift slowly and slightly but continuously as the environment changes; e.g., cleanliness of the touch surface (e.g., water drops, oil stain), will cause the reference line to suddenly shift up or down; for example, the ripple of a single source of the system can make the signal line fluctuate along with the fluctuation of the ripple; for example, noise and interference from other devices in the surrounding environment (such as radio frequency signals of mobile phones and electromagnetic signals of microwave ovens) will cause the reference line to change rapidly and violently due to the interference; even the thermal noise caused by the chip manufacturing process can cause the reference line to rapidly shake up and down with small amplitude.

Since the reference line reflects the sensing condition of the capacitance signal when the key is not touched, the reference line should change along with the change of the actual environment, otherwise, the instability of the reference line in the above various scenes can greatly increase the difficulty of correctly judging whether the key is touched, and the condition of false triggering or non-triggering is likely to occur.

The touch switch system and electronics continuously correct the reference value to accommodate changes in ambient operating conditions. For example, when the touch key is heated up, the capacitance is changed, and finally the touch reference value is increased or decreased. To accommodate these changes in the reference value, the touch switch system and the electronic device need to gradually adjust the reference value following the changes in the environment.

For example, if water or some other conductive liquid is sprayed onto the touch key, the continuous correction routine may adjust to this condition so that a touch event is falsely reported when water is removed.

As shown in fig. 11, which is a time plot of exemplary sensed values (touch data) representing data available from keys on a capacitive touch key device, is illustrated with reference to a line-change diagram. The Y-axis in fig. 11 represents the count value, which is a numerical value after the preprocessing. The X-axis refers to samples taken at different points in time, which represent samples taken repeatedly by the touch detection controller controlling the touch detection unit. The 701 sensing line is composed of a plurality of sensing values. The reference line 702 generally follows the trend of the curve of the sense line 701.

When the sense line exceeds the touch line, considered a touch, the reference line will not update the baseline for the duration of the touch event, T0+ T1.

Considering the situation where the reference line does not change with the change of the environment, the sensing line drifts upward as shown in 704, for example, the scene of the signal with the change of the environment temperature, although the reference line 702 remains unchanged, but the sensing line is not judged as a touch by mistake because of the upward drift, then scenes such as water drop can cause the sensing line to slowly and continuously step down, as shown in 705, because the touch system can not recognize the change of the environment, the reference line 702 remains unchanged, as shown in 706, after the timing is accumulated to , the sensing line exceeds the touch line, and the sensing line is judged as a touch by mistake.

When scenes such as water drops occur, the sensing line slowly and continuously steps down, 705, since the touch system can recognize the change of the signal environment, the reference line 703 is expected to change along with the change of the sensing line, and in the case that the touch threshold is not changed (i.e. the descending amplitude of the signal is not changed during the touch), 707 is expected to change along with the change of the expected reference line, so the sensing line does not exceed the touch line, and the judgment of false touch is avoided.

The invention has the significance that a signal scene is identified through analyzing the signal, and the reference line is processed differently according to the signal scene where the signal is located, so that the reference line is ensured to change along with the change of the environment, wherein the identification of the signal scene is realized by a signal scene classifier.

The signal scenes are different due to different actual environments, and finally the sensing values are different under different signal scenes and are reflected in three dimensions of the change rate, the change intensity and the duration of the sensing values relative to the reference value, wherein the change rate α is determined by the change intensity in the change time T0 and T0, the change rate is larger when the change intensity in the same T0 is larger, and the change intensity and the duration T1 thereof are different.

In order to accurately define the variation intensity, the variation intensity range needs to be defined according to the touch system, as shown in the signal scene classification diagram of fig. 13, the minimum signal line, the maximum signal line, the lower noise line and the upper noise line are included in addition to the reference line and the touch line. After the scenes of the signals are identified through three dimensions, different self-adaptive processing can be performed on the reference values according to different scenes, and the accuracy of touch detection is improved.

As shown in fig. 13, 8 signal scenes can be abstracted out:

signal scene, the sensing line changes in negative direction relative to the reference line, the change intensity is less than the noise reduction line, and the duration is signal scene time T1;

second signal scenario: the sensing line changes positively relative to the reference line, the change strength is smaller than that of the upper noise line, and the duration is the second signal scene time T2;

third signal scenario: the sensing line is opposite to the reference line, and the sensing line shakes up and down in the range of the upper noise line and the lower noise line;

fourth signal scenario: the sensing line changes positively relative to the reference line, the change strength is greater than the upper noise line and less than the maximum signal line, and the duration is fourth signal scene time T4;

fifth signal scenario: the sensing line changes positively relative to the reference line, the change strength is greater than the maximum signal line, and the duration is the fifth signal scene time T5;

sixth signal scenario: the sensing line changes in a negative direction relative to the reference line, the change strength is greater than the lower noise line and less than the touch line, and the duration is the sixth signal scene time T6;

seventh signal scenario: the sensing line changes in a negative direction relative to the reference line, the change strength is greater than the touch line and less than the minimum signal line, and the duration is a seventh signal scene time T7;

eighth signal scenario: the sensing line changes in a negative direction relative to the reference line, the change strength is greater than the minimum signal line, and the duration is an eighth signal scene time T8;

a description of the signal scene recognition process is made with reference to fig. 11, 12, and 13.

Firstly, after a signal scene classification program starts, executing acquisition times clear 0;

next, an ith sensing value Data [ i ] is acquired, wherein i is calculated from 0;

next, the variation of the i-th time sensing value Data [ i ] and the i-1 st time sensing value Data [ i-1] is calculated, the sensing variation σ [ i ] being Data [ i ] -Data [ i-1 ];

judging whether the data collection of N times is finished, if not, continuing the collection, if so, calculating the change rate, wherein the change rate α is sigma/time, because the interval of the collected data is fixed, the collection time reflects the collection time, and the accumulated value of the sigma reflects the change intensity in the period;

if the change rate is a positive change rate, continuously judging the change intensity and the change duration:

the variation intensity of the sensing line is smaller than that of the upper noise line, and when the duration time is the second signal scene time T2, the sensing line is the second signal scene;

the variation intensity of the sensing line is greater than the upper noise line and less than the maximum signal line, and the duration is the fourth signal scene time T4, so that the sensing line is the fourth signal scene;

the variation intensity of the sensing line is greater than the maximum signal line, the duration is the fifth signal scene time T5, and then the sensing line is the fifth signal scene;

if the change rate is a negative change rate, continuously judging the change intensity and the change duration:

the variation intensity of the sensing line is less than that of the lower noise line, the duration is signal scene time T1, and then the signal scene is signal scene;

the variation intensity of the sensing line shakes up and down in the range of the upper noise line and the lower noise line, and the third signal scene is obtained;

the variation intensity of the sensing line is greater than that of the lower noise line and less than that of the touch line, and the duration is the sixth signal scene time T6, so that the sensing line is a sixth signal scene;

the sensing line variation strength is greater than the touch line and less than the minimum signal line, the duration is the seventh signal scene time T7, and then the signal scene is a seventh signal scene (touch scene);

the variation intensity of the sensing line is greater than the minimum signal line, the duration time is the eighth signal scene time T8, and the sensing line is the eighth signal scene;

if the change rate is 0, it indicates that the sensing line is not changed, and special scenes which are the third signal scene belong to the third signal scene.

Storing the current signal scene by using a signal scene memory, wherein the signal memory can be an RAM or an FLASH; comparing the current signal scene with the last signal scene using a signal scene comparator, which conventionally may be implemented using a program, such as subtracting a previously stored signal scene from the latest signal scene;

according to the scene comparison result, signal processing of the same scene is carried out by using an intra-scene processor, or switching and signal processing of different scenes of the signal are carried out by using an inter-scene processor, if the signal processing of the same scene is carried out, the signal processing mode of the current scene is kept, and if the signal processing of the inter-scene is carried out, the signal processing mode of the latest scene is started, the following processing modes are generally adopted:

the th signal scenario, wherein the reference line is the th signal scenario constant, , and the th signal scenario constant can be removed by 0.2 to 0.5 times the difference between the noise line and the reference line;

a second signal scenario, wherein the reference line + a second signal scenario constant, , is defined as the signal scenario constant, wherein the noise line is removed from the reference line by a factor of 0.3 to 0.6;

third signal scenario: the reference line is the reference line;

a fourth signal scenario, where the reference line + a fourth signal scenario constant may be between 0.2 and 0.5 times the sense and reference line difference;

a fifth signal scenario, wherein the reference line + a fifth signal scenario constant may be between 0.6 and 0.8 times the sense and reference line difference;

a sixth signal scenario, where reference line-sixth signal scenario constant may be between 0.6 and 0.8 times the sense and reference line difference;

seventh signal scenario: the reference line is regarded as touch generation, and the reference line is not adjusted;

eighth signal scenario: a reference line is a sensing line;

the key detection is performed , a sampling sensing line is compared with a touch line, if the sampling sensing line exceeds the touch line, the touch is considered to be generated at this time, and the key debouncing operation is performed through key duration (the number of times of continuous touch generation detection within time is usually adopted).

The cooperative working effect of the touch detection unit, the touch detection controller, the signal preprocessor, the signal scene classifier, the signal scene memory, the signal scene comparator, the signal scene processor, and the key information determiner is as shown in fig. 14, which is a schematic diagram of signal scene switching:

when the change rate and the change intensity of the sensing lines exceed the touch lines and are smaller than the minimum signal line, when the duration time T1001 meets the requirement (exceeds the seventh signal scene time T7), the sensing line is considered to be a touch generation, and the sensing line is a seventh signal scene;

then, the change rate and the change intensity of the sensing line exceed the minimum signal line, when the duration time T1002 meets the requirement (exceeds the eighth signal scene time T8), the sensing line is considered to be switched into an eighth signal scene, the signal is processed according to the eighth signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, and the self-adaptive 'water rising ship height' is realized;

then, the change rate and the change intensity of the sensing line exceed the upper noise line and are less than the maximum signal line, when the duration time T1003 meets the requirement (exceeds the fourth signal scene time T4), the sensing line is considered to be switched into a fourth signal scene, the signal is processed according to the fourth signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, the self-adaptive 'water rising ship height' is realized, and if the sensing line is continuously kept in the fourth scene, the adjustment is continuously carried out within the duration time T1004, as shown by a step shape in the figure;

then, when the sensing line change rate and the change intensity exceed the touch line and are smaller than the minimum signal line, and when the duration time meets the requirement (exceeds a seventh signal scene time T7), the sensing line is considered to be touch generation, and the sensing line is a seventh signal scene;

then, the sensing line change rate and the change intensity are in the lower noise line, when the duration T1005 meets the requirement (exceeds the th signal scene time T1), the sensing line is considered to be switched to the th signal scene, the signal is processed according to the th signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, the adaptive "water ship height" is realized, and if the sensing line continues to be kept in the th scene, the sensing line continues to be adjusted step by step within the duration T1006, as shown by a step shape in the figure;

next, the change rate and the change intensity of the sensing line are in the upper noise line, when the duration time T1007 meets the requirement (exceeds the time T2 of the second signal scene), the sensing line is considered to be switched to the second signal scene, the signal is processed according to the second signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, and the self-adaptive 'water rising ship height' is realized;

then, the change rate and the change intensity of the sensing line exceed the lower noise line and are smaller than the touch line, when the duration time T1008 meets the requirement (exceeds the sixth signal scene time T6), the sensing line is considered to be switched to the sixth signal scene, the signal is processed according to the sixth signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, and the self-adaptive 'water rising ship height' is realized;

then, the change rate and the change intensity of the sensing line exceed the maximum signal line, when the duration time T1009 meets the requirement (exceeds the time T5 of a fifth signal scene), the sensing line is considered to be switched into the fifth signal scene, the signal is processed according to the fifth signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, and the self-adaptive 'water rising ship height' is realized;

then, the change rate and the change intensity of the sensing line exceed the lower noise line and are smaller than the touch line, when the duration time T1010 meets the requirement (exceeds the sixth signal scene time T6), the sensing line is considered to be switched into a sixth signal scene, the signal is processed according to the sixth signal scene, the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line are correspondingly adjusted, the self-adaptive 'water rising ship height' is realized, and if the sensing line is continuously kept in the sixth scene, the sensing line is continuously adjusted step by step within the duration time T1011, as shown in a step shape in the figure;

then, the sensing line change rate and the change intensity are jittered in the upper and lower noise lines, when the duration time meets the requirement (exceeds the third signal scene time T3), the sensing line is considered to be switched into the third signal scene, the signal is processed according to the third signal scene, and the maximum signal line, the upper noise line, the lower noise line, the reference line, the touch line and the minimum signal line do not need to be adjusted.

In another embodiment, the invention further discloses electronic devices, which include or more touch switches, a touch detection unit, a signal scene classification unit, a signal scene storage unit, a scene comparison unit, a scene processing unit, an inter-scene processing unit and a key information determination unit, wherein the touch detection unit is used for collecting touch key signals to obtain current signal sensing values, and the sensing values are the number of pulses within hours;

a signal scene storage unit for storing a current signal scene;

It should be noted that, as one of ordinary skill in the art would understand, all or part of the steps of implementing the above method embodiments may be implemented by hardware associated with program instructions, the foregoing program may be stored in a computer-readable storage medium, and when executed, the program performs the steps including the above method embodiments, and the foregoing storage medium includes: ROM, RAM, magnetic or optical disks, or the like.

Finally, it should be noted that the above description is only a preferred embodiment of the present invention, and is only used for illustrating the technical solutions of the present invention, and is not used to limit the protection scope of the present invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention shall fall within the protection scope of the present invention.

Claims

1, scene type signal self-adaptive processing method of capacitance touch key, characterized by comprising the following steps:

collecting touch key signals to obtain current signal sensing values, wherein the sensing values are the number of pulses within fixed time;

classifying the signal scene according to the change rate, the change intensity and the change duration of the sensing values to determine the current signal scene;

storing a current signal scene;

comparing the current signal scene with the last signal scene to determine whether the scene changes;

if the signal scene is not changed, using the signal processing mode of the same scene;

if the signal scene changes, the scene is switched, and a signal processing mode of a new scene is used;

and performing key signal processing according to the signal processing mode.

2. The adaptive scene-based signal processing method for capacitive touch keys according to claim 1, wherein the acquisition of the touch key signal employs relaxation oscillation frequency measurement or charge transfer measurement-based touch signal detection.

3. The method for adaptively processing the scene-type signal of the capacitive touch key as claimed in claim 1, wherein after the signal of the touch key is collected, the signal is preprocessed, specifically, the preprocessing is a two-stage processing, the th stage processing is dynamic tracking filtering of a sliding window, and the second stage processing is inertial filtering.

4. The capacitive touch key scene-type signal adaptive processing method as recited in claim 3, wherein the sliding window dynamic tracking filtering is implemented by considering continuously obtained N sensing values as queues, fixing the length of the queues to be N, and performing arithmetic mean operation on N data in the queues by using a first-in first-out principle to obtain a new filtering result.

5. The method for adaptively processing scene-based signals of a capacitive touch key according to claim 3, wherein the inertial filtering specifically comprises: filtering is performed using the following formula

The current filtering result is (1-a) + a current signal value + a last filtering result;

wherein, the value range of a is between 0 and 1.

6. The method as claimed in claim 1, wherein the variation rate, the variation intensity and the variation duration are selected from the group consisting of continuously collecting sensing values, recording the ith sensing value as Data [ i ], measuring the sensing variation σ [ i ] for the ith time as Data [ i ] -Data [ i-1], accumulating the sensing variation σ [ i ] to σ, and initializing σ to 0, until i reaches the preset maximum acquisition time or the absolute value of σ [ i ] is smaller than the preset th threshold, the variation rate is σ/N, the variation intensity is the absolute value of σ, and the variation time is i multiplied by the single acquisition time.

7. The method of claim 1, wherein said signal scene classification based on the sensing value change rate, change intensity and change duration comprises at least following scenes:

8. The method of claim 7, wherein the signal processing using the new scene comprises adjusting a reference line using the following method:

when the current scene is determined to be the seventh signal scene, generating touch without adjusting the reference line;

9. The method for adaptively processing scene-based signals of a capacitive touch key according to claim 8, wherein after the reference line is re-determined, the minimum signal line, the lower noise line, the touch line, the upper noise line and the maximum signal line are re-determined according to a difference or a ratio of an original minimum signal line, an original lower noise line, an original touch line, an original upper noise line and an original maximum signal line to the original reference line.

10. The method as claimed in claim 1, wherein the performing of the key signal processing according to the signal processing method is specifically that the key is pressed when the sensing value is greater than the touch line within times, otherwise the key is not pressed.