CN203455812U - Touch sensor - Google Patents
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- CN203455812U CN203455812U CN201320465024.5U CN201320465024U CN203455812U CN 203455812 U CN203455812 U CN 203455812U CN 201320465024 U CN201320465024 U CN 201320465024U CN 203455812 U CN203455812 U CN 203455812U
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Abstract
A touch sensor can sense approaching or touching of the human body without being affected by noise in a periodic and noisy environment. The touch sensor comprises a detection electrode for detecting approaching or touching of the fingers and other parts of the human body, a measurement circuit, a detection circuit, a first timing circuit, a second timing circuit, a time comparison circuit and a value comparison circuit, wherein the measurement circuit is used for measuring electric amount corresponding to static electric capacitance generated in the position of the detection electrode, the detection circuit outputs detection signals when the measurement value obtained by the measurement circuit exceeds a set threshold, the first timing circuit times a specified period, the second timing circuit is used for timing the total time of outputting detection signals by the detection circuit during the period that the first timing circuit carries out timing, the time comparison circuit works out the comparison value between the specified period timed by the first timing circuit and the total time obtained by the second timing circuit, and the value comparison circuit compares the comparison value obtained by the time comparison circuit and a specified value.
Description
Technical field
The utility model relates to a kind of touch sensor, relates in detail a kind of impact that can not be subject to this noise in the environment that periodically noise is many and touches the touch sensor of detection.
Background technology
In the past, in doors with room outside various devices, equipment in be widely used touch sensor, used the soft-touch control of this touch sensor, this touch sensor approaches or the operation part of contact possesses one or more detecting electrode at people's finger etc., by carrying out the approaching of sensing human body or contact to the stray capacitance producing at this detecting electrode place or with variation measurements of electrostatic capacitance between ground connection (the earth).
In this touch sensor, there is following problem: if be judged as the contact that has human body when only observing the variation of the electric parameters corresponding with electrostatic capacitance and surpassing (or lower than) fixing threshold value in its value, because the electrostatic capacitance producing at detecting electrode place is broken along with environment etc. changes or detected electric parameters is subject to noise impact changes to produce to judge by accident.
As the countermeasure of this problem, such as having used situation about reaching more than the set time over threshold value in the electric parameters corresponding with electrostatic capacitance to judge as there is the whole bag of tricks such as contact of human body.In addition, known following a kind of touch sensor (with reference to patent documentation 1): do not touch accurately detection in order to rely on the environmental changes such as temperature, electrostatic capacitance change between detecting electrode is detected and obtains its pace of change, variation the moment of the variation from more than having there is the pace of change of regulation more than the pace of change of this regulation has continued the stipulated time when above, determines to touch and detects.
Patent documentation 1: Japanese kokai publication hei 11-136116 communique
Utility model content
The problem that utility model will solve
Due to the human body proximities such as finger or contact (touch) detecting electrode, the stray capacitance producing at detecting electrode place or and the earth between electrostatic capacitance, the electrostatic capacitance producing between two detecting electrodes change.About to changing in touch sensor that corresponding electric parameters detects or soft-touch control and the threshold value of the measured value of detected electric parameters and regulation compared, judge as there is the method for the touch of human body in the situation that for example more than the set time surpasses continuously threshold value with this electrostatic capacitance or its, there is following problem: while comprising noise in detected electric parameters, in the change up and down of threshold value, exist sensing less than the situation of the touch of finger of people etc.In addition, even the electric signal that will detect is filtered in order to remove noise contribution, in the situation that there is large noise, be also difficult to obtain touch and sensitivity and the good touch sensor of response of sensing human body reliably.
In addition, even if the pace of change that to be made as when the pace of change of electrostatic capacitance as recorded in above-mentioned patent documentation 1 be regulation is above and determine during the lasting set time and touch detection, in the signal of the electrostatic capacitance that will detect, superpose in noisy situation, due to the value of pace of change in during this set time, towards changing, therefore also there is the problem of the touch of sensing human body reliably.
That is,, in any method for sensing as above, in the situation that change in the signal of corresponding electric parameters and comprise noise with electrostatic capacitance or its, be all difficult to the touch of sensing human body exactly.As the noise that touch sensor is impacted, there is periodic noise, this periodic noise by human body sensing, has the cycle (frequency) of fixed range from various power circuits, motor etc.For example there is following situation: sensed via stray capacitance, human body from the source power supply exchanging, in the signal of detected electrode detection, be mingled with this alternating current impression noise.
The utility model is in view of problem as above, and its object is to provide a kind of touch sensor that approaches or contact that can not be subject to the impact ground sensing human body of this noise in the environment that periodically noise is many.
For the scheme of dealing with problems
In order to address the above problem, the touch sensor of this first utility model is a kind of touch sensor that approaches or contact for detection of human body, and its aim is to possess: the detecting electrode of human body proximity or contact; Metering circuit, it measures the electric parameters corresponding with the electrostatic capacitance producing at above-mentioned detecting electrode place; Testing circuit, it is output detection signal when the measured value being obtained by above-mentioned metering circuit surpasses the threshold value setting; The first timing circuit, it carries out the timing of specified time limit from timing starts; The second timing circuit, its utilize above-mentioned the first timing circuit carry out timing during, to export the T.T. of the time of above-mentioned detection signal from above-mentioned testing circuit, carry out timing; Time comparison circuitry, it obtains during the afore mentioned rules that utilizes above-mentioned the first timing circuit timing the fiducial value with the above-mentioned T.T. of utilizing above-mentioned the second timing circuit timing to obtain; And value comparator circuit, it will utilize above-mentioned fiducial value and the setting that above-mentioned time comparison circuitry is obtained to compare.
The aim of this second utility model is, in above-mentioned the first utility model, in the situation that comprise known noise of cycle in utilizing the change of the above-mentioned electric parameters that above-mentioned metering circuit measures, above-mentioned the first timing circuit carries out timing using the time that surpasses the one-period of above-mentioned noise during afore mentioned rules.
The aim of this 3rd utility model is, in above-mentioned the second utility model, also to possess: the 3rd timing circuit, and it will carry out timing from time as the continuous time of the above-mentioned detection signal of above-mentioned testing circuit continuous wave output; And second value comparator circuit, it compares above-mentioned continuous time and the second stipulated time of utilizing above-mentioned the 3rd timing circuit timing to obtain.
The aim of this 4th utility model is, in above-mentioned the second utility model, also to possess: filtering circuit, and it reduces the above-mentioned noise contribution in the change of the measured value that obtained by above-mentioned metering circuit; And Threshold circuit, it is according to setting above-mentioned threshold value by the signal of above-mentioned filtering circuit.
The aim of this 5th utility model is, in above-mentioned the 3rd utility model, also to possess: filtering circuit, and it makes to utilize the composition of the above-mentioned noise in the signal that above-mentioned metering circuit measures to reduce; And Threshold circuit, it is according to setting above-mentioned threshold value by the signal of above-mentioned filtering circuit.
The aim of this 6th utility model is, in above-mentioned the first utility model, also to possess: the 3rd timing circuit, and it will carry out timing from time as the continuous time of the above-mentioned detection signal of above-mentioned testing circuit continuous wave output; And second value comparator circuit, it compares above-mentioned continuous time and the second stipulated time of utilizing above-mentioned the 3rd timing circuit timing to obtain.
The effect of utility model
Touch sensor according to this first utility model, possesses: the detecting electrode of the human body touch such as finger (approaching or contact); Metering circuit, it measures the electric parameters corresponding with the electrostatic capacitance producing at detecting electrode place; Testing circuit, it is output detection signal when the measured value being obtained by above-mentioned metering circuit surpasses the threshold value setting; The first timing circuit, its from timing starts to carrying out timing specified time limit; The second timing circuit, its utilize above-mentioned the first timing circuit carry out timing during, to exporting the T.T. of the time of above-mentioned detection signal, carry out timing; Time comparison circuitry, it obtains during the afore mentioned rules that utilizes above-mentioned the first timing circuit timing the fiducial value with the above-mentioned T.T. of utilizing above-mentioned the second timing circuit timing to obtain; And value comparator circuit, it will utilize above-mentioned fiducial value and the setting that above-mentioned time comparison circuitry is obtained to compare, therefore with the fixed cycle, utilize at the appointed time above-mentioned metering circuit to measure, by by its measured value, T.T. and the afore mentioned rules time over threshold value compares, can judge the touch of human body.; this touch sensor can be obtained specified time limit and the fiducial value of the measured value being obtained by this metering circuit over the T.T. of the time (from the time of testing circuit output detection signal) of threshold value; and this fiducial value and setting are compared, thereby determine whether the touch that has human body.For example,, when for specified time limit and the ratio that T.T. is regulation when above can be judged to be the touch that has human body.Thus, about this touch sensor, even if comprise periodic noise in detected electric parameters or the signal corresponding with its variation, measured value, also can be according to add up to surpassing the time of threshold value the T.T. touch of sensing human body reliably obtaining within specified time limit in the situation that threshold value changes up and down due to noise.In addition, compare with the situation of removing noise by strong filter unit, this touch sensor is easy to maintain detection sensitivity and the response for touching.
In the situation that comprise known noise of cycle in the change of the measured value being obtained by above-mentioned metering circuit, above-mentioned the first timing circuit carries out timing using the time that surpasses the one-period of above-mentioned noise during afore mentioned rules, in this case, noise by the cycle for fixed range (frequency) determine appropriate during, can compare the cycle in the change that comprises the measured value causing with touch by human body and effectively carry out the touch-sensing of human body during short noise.
In addition, also possess: the 3rd timing circuit, it will carry out timing from time as the continuous time of the above-mentioned detection signal of above-mentioned testing circuit continuous wave output; And second value comparator circuit, it compares above-mentioned continuous time and the second stipulated time of utilizing above-mentioned the 3rd timing circuit timing to obtain, in this case, when the measured value being obtained by above-mentioned metering circuit reached for the second stipulated time over the threshold value setting continuously, can be judged as and have approaching or contact of human body.Thus, about this touch sensor, in the situation that do not comprise large noise in the change of above-mentioned measured value, also can be fast and the stably touch of sensing human body.
Also possess: filtering circuit, it reduces the above-mentioned noise contribution in the change of the measured value that obtained by above-mentioned metering circuit; And Threshold circuit, it is according to setting above-mentioned threshold value by the signal of above-mentioned filtering circuit, in this case, can, based on be removed the change of the measured value of noise contribution by filtering circuit, always correspondingly set best threshold value with the level of measured value.Thus, about this touch sensor, not only can set accordingly best threshold value with environmental change, can also remove noise by appropriate filter effect, and according to above-mentioned T.T. or the touch of carrying out more exactly human body above-mentioned continuous time, judge when guaranteeing the detection sensitivity of touch sensor and response.
Accompanying drawing explanation
About the utility model, enumerated the example being not intended to limit of typical embodiment of the present utility model, with reference to mentioned a plurality of accompanying drawings, describe further on one side by following detailed narration on one side, identical reference marker represents identical parts in several figure of accompanying drawing.
Fig. 1 is the block diagram that conceptually represents this touch sensor.
Fig. 2 means the schematic block diagram of the structure of the touch sensor that present embodiment is related.
Fig. 3 means the schematic block diagram of the structure of the touch sensor that possesses filtering circuit and Threshold circuit.
Fig. 4 represents the change of the measured value that obtained by metering circuit and the curve map of the threshold value that sets for the action of the touch sensor that present embodiment is related is described.
Fig. 5 means the change of the measured value being obtained by metering circuit and the curve map of the threshold value set by filter unit.
Fig. 6 is for the process flow diagram of the control method of touch sensor is described.
Fig. 7 means the change of the measured value being obtained by metering circuit and by filtering in the past, processes the curve map of the threshold value of setting.
Fig. 8 carries out for the change of the measured value being obtained by metering circuit the curve map that the situation that removes noise is processed in stronger filtering.
Description of reference numerals
1,11: touch sensor; 2: detecting electrode; 3: metering circuit; 31: filtering circuit; 32: Threshold circuit; 4: judging part; 41: T.T. sensing cell; 410: testing circuit; 411: the first timing circuits; 412: the second timing circuits; 413: time comparison circuitry; 414: value comparator circuit; 42: continuous time sensing cell; 422: the three timing circuits; 424: the second value comparator circuits; 9: human body.
Embodiment
Below, with reference to Fig. 1～Fig. 8, explain touch sensor of the present utility model.
In the item shown in this, for illustrated content and embodiment of the present utility model being described illustratively, providing, think and can the object that be illustrated as the most effective and easy to understand principle of the present utility model and conceptional features narrate.Based on this point, be not to be intended to exceed the required degree of basic comprehension of the present utility model detailed structure of the present utility model is shown, but the explanation of carrying out in conjunction with the drawings make those skilled in the art understand that in fact how several embodiment of the present utility model embodies.
1. the structure of touch sensor
Fig. 1 is the block diagram that represents synoptically this touch sensor.This touch sensor 1 is that the approaching or contact for detection of human body (is called " touch " by " approach or contact " below.) touch sensor, possess detecting electrode 2 that human body 9 touches, for measuring with the electrostatic capacitance or its metering circuit 3 that changes corresponding electric parameters that produce at detecting electrode 2 places and using the measured value of periodically being measured by metering circuit 3 to judge the judging part 4 of the touch of human body 9.In addition, touch sensor 1 possesses for making the not shown power supply etc. of metering circuit 3 and judging part 4 actions.
Detecting electrode 2 is set as human body proximity or is contacted its surperficial electric conductor, and its quantity, shape, size, structure etc. are not limited especially.In addition, the material of electric conductor is not limited especially yet, except metal, can also use conductive fabric etc.At this, " approaching " of the so-called human body to detecting electrode 2, except making palm, finger near the surperficial mode of detecting electrode, also comprise the mode that human body contacts via the surperficial insulant that covers detecting electrode, " contact " is made as to the surperficial mode of the direct contact detection electrode of human body.
Judging part 4 is configured to and makes metering circuit 3 measure with the cycle (sampling period) of fixing the electric parameters producing at detecting electrode place, and inputs the measured value being obtained by metering circuit 3.Can suitably set the sampling period (for example 1ms).In addition, the setting processing of calculation process, threshold value is carried out in the change that judging part 4 is configured to based on this measured value.This threshold value can be made as to predefined value.But, generally except touch have or not, due to the difference of the environment such as temperature, humidity, the electric parameters producing at detecting electrode 2 places also changes, the level of the measured value consequently being obtained by metering circuit 3 changes, therefore preferred successive adjustment setting threshold.
And judging part 4 is configured to the comparison of threshold value by setting and measured value and has the touch of human body to detecting electrode 2, the calculating of time (Tc continuous time) that measured value surpasses threshold value continuously and the processing such as calculating of the T.T. (T.T. Ts) of the time that measured value surpasses threshold value determine whether.In addition, in the following drawings, when there is touch, the measured value being obtained by metering circuit 3 is lower than threshold value, and the state that surpasses threshold value in the direction by measured value when there is touch is called " having surpassed threshold value ".
Processing about judging part 4, can realize by any in hardware, software, it is desirable to can by centered by the microcontroller (microcomputer) to possess not shown CPU, storer (ROM, RAM etc.), imput output circuit etc., possess the peripheral circuits such as IO interface and form.In addition, also can form with programmable logical circuit, gate matrix and other logical circuit.Also can be in this microcontroller etc. built-in above-mentioned metering circuit 3.
In addition, judging part 4 can be configured to various devices, equipment (such as illumination, air-conditioning, AV equipment, automatic open-close type window etc.) and be electrically connected to, in the situation that be judged to be the state of human body proximity or contact, by this judgement or for carrying out the proximity test signal S of the action based on judging, output to these devices etc.
In judging part 4, possesses T.T. sensing cell 41, this, sensing cell 41 obtained the summation that the measured value of being measured by metering circuit 3 surpasses the time of above-mentioned threshold value within specified time limit (Tat) T.T., when this T.T. Ts is with respect to being judged as and having approaching or contact of human body when Tat is for more than the ratio of regulation time specified time limit.At this, (below also referred to as " during object ") Tat during afore mentioned rules can be made as since during the length predetermining of any time.In addition, for Tat during object, can predetermine than short time of Tat during object as the time more than ratio of regulation.
In addition, because extraneous noise makes the electric parameters producing at detecting electrode 2 places, change and therefore in the situation that the measured value being obtained by metering circuit 3 changes in time, be difficult to by judging part 4 touch of sensing human body exactly.As the noise that touch sensor 1 is impacted, there is periodic noise, this periodic noise is from various power circuits around, motor etc. by human body sensing and have cycle (frequency) of fixed range.For example, there is following situation: sensed and in the change of the signal being detected by detecting electrode 2 and measured value thereof, comprise the alternating current impression noise (with reference to Fig. 4) of the frequency of supply frequency (50Hz or 60Hz) or its integral multiple via stray capacitance, human body etc. from the wiring of source power supply and equipment etc.
In the situation that comprise the known noise of cycle as alternating current impression noise in the change in time of the measured value of being measured by metering circuit 3, Tat during object can be made as to time over the one-period of this noise (being preferably 2～4 times of one-period of noise).Can be for cycle of the fixed range of noise Tat during decision objects suitably, for Tat during object, suitably determine the time (for example time of 0.5～2 times of left and right of the time of 15～50% left and right during object or the one-period of noise) more than requirement ratio, the touch-sensing of the human body in the time of can effectively comprising thus than the short periodic noise of Tat during object.
Judging part 4 is except the touch by above-mentioned T.T. sensing cell 41 judgement human bodies, can also possess sensing cell 42 continuous time, sensing cell 42 surpassed continuously and when above-mentioned threshold value reached for the second stipulated time, was judged as the touch that has human body at the measured value being obtained by metering circuit 3 continuous time this.Can suitably set above-mentioned the second stipulated time (for example, 0.5～2 of the one-period of noise times of left and right).By possessing this of sensing cell 42 continuous time, in the situation that do not comprise large noise in the change of the measured value being obtained by metering circuit 3, if the time (Tc continuous time) that measured value surpasses threshold value continuously for the set time above; be judged as to exist and touch, can be fast and the stably touch of sensing human body.
Conventionally, in the change of the measured value being obtained by metering circuit 3, comprise noise, therefore preferably remove noise contribution.In addition, the benchmark that the measured value being obtained by metering circuit 3 for basis takes a decision as to whether touch condition, along with the environmental baselines such as temperature, humidity change, therefore preferably successively calculates and sets above-mentioned threshold value.The signal (filtering signal) that therefore, can be configured to the above-mentioned filter unit generation of the above-mentioned noise in the change of the measured value based on via stoping (minimizings) to be obtained by metering circuit 3 is set above-mentioned threshold value.
Above-mentioned filter unit is not limited especially, for example, can be configured to the hardware or the software that by judging part 4, possess the change of the measured value being produced by metering circuit 3 is carried out to filtering processing.In addition, also can be configured to, in metering circuit 3, the signal of the electric parameters based on producing at detecting electrode 2 places generates filtering signal via low-pass filter circuit, with this filtering signal, carrys out setting threshold.Be configured in a word characteristic, the progression that can set arbitrarily wave filter, the change of measured value based on having removed the noise of certain limit, by having used the appropriate computing of hardware or software to implement, for touching the adjustment of judgement, to set thus above-mentioned threshold value.
As an example, in Fig. 5, enumerate the change of the measured value Cx based on being obtained by metering circuit, by the filtering of software, processed the example of setting threshold.This figure is following example: use the computing that once lags behind on two rank to carry out filtering processing to the periodic measured value Cx being obtained by metering circuit 3, by the adjusted value of the output valve on each rank and regulation being carried out to computing, obtain as the threshold value that touches the benchmark of judging.Using known filtering circuit also can form identical filtering processes.
Specifically, can form as shown in Figure 2 the related touch sensor of present embodiment.Identical with above-mentioned situation with metering circuit 3 about detecting electrode 2.In the structure shown in Fig. 2, above-mentioned judging part 4 possesses: testing circuit 410, output detection signal A when its signal at the measured value Cx from metering circuit 3 outputs surpasses the threshold value setting; The first timing circuit 411, it carries out the timing of Tat specified time limit from timing starts; The second timing circuit 412, its utilize the first timing circuit 411 carry out timing during, to the T.T. of the time of output detection signal A (Ts) carrying out timing; Time comparison circuitry 413, its obtain utilize the first timing circuit 411 timing specified time limit Tat with the fiducial value (Cs) that utilizes the T.T. Ts that the second timing circuit 412 timing obtain; And value comparator circuit 414, it compares the fiducial value Cs and the setting that utilize time comparison circuitry 413 to obtain.Value comparator circuit 414 can be configured to and when fiducial value Cs surpasses setting, export proximity test signal S.
In said structure, above-mentioned T.T. sensing cell 41 by testing circuit 410, the first timing circuit 411, the second timing circuit 412, time comparison circuitry 413 and value comparator circuit 414, formed.
The first timing circuit 411 can consist of the timer that Tat during the object predetermining is carried out to timing.The first timing circuit 411 can be configured to the signal being expressed as in timing is outputed to the second timing circuit 412, time comparison circuitry 413 etc.The timing that utilizes the first timing circuit 411 to start timing is arbitrarily, for example, can also be provided for starting with the cycle longer than Tat during object the timer of the first timing circuit 411.
The second timing circuit 412 is configured to and uses known timer or counting circuit, during utilizing the first timing circuit 411 to carry out object, in the timing course of Tat, measures from the T.T. Ts of the time of testing circuit 410 output detection signal A.Even without output detection signal A continuously, as long as the time of exporting is added up as T.T. Ts.
In the situation that comprise known noise of cycle in the change of the electric parameters of being measured by metering circuit 3, the first timing circuit 411 can be configured to Tat time as specified time limit that surpasses the one-period of above-mentioned noise is carried out to timing.
In addition, above-mentioned judging part 4 can also possess: the 3rd timing circuit 422, its using from testing circuit 410 continuously Tc time as continuous time of output detection signal A carry out timing; And the second value comparator circuit 424, it exports proximity test signal S when Tc continuous time being obtained by the 3rd timing circuit 422 timing surpassed for the second stipulated time.In this case, this touch sensor can be configured to from value comparator circuit 414 and the second value comparator circuit 424 and all export proximity test signal S.
In said structure, above-mentioned continuous time, sensing cell 42 consisted of the 3rd timing circuit 422 and the second value comparator circuit 424.
The 3rd timing circuit 422 can form with known timer or counting circuit.The 3rd timing circuit 422 also can be only having inputted signal from the expression timing of above-mentioned the first timing circuit 411 outputs during carrying out object the timing of Tat during to continuous time Tc carry out timing.
The second value comparator circuit 424 can be configured to use known digital comparator etc. to utilize the 3rd timing circuit 422 timing and obtain continuous time Tc and the second stipulated time compare.Can predetermine for the second stipulated time.And the second value comparator circuit 424 can be configured to and export proximity test signal S when continuous time when Tc surpassed for the second stipulated time.
And as shown in Figure 3, touch sensor (11) can possess the filtering circuit 31 of the noise contribution minimizing of the signal for making to be measured by metering circuit 3.The signal being generated by filtering circuit 31 (filtering signal) is sent to testing circuit 410.In addition, this touch sensor can be configured to be possessed for setting the Threshold circuit 32 of above-mentioned threshold value, from filtering circuit 31, to Threshold circuit 32, sends filtering signal.
Above-mentioned filter unit consists of filtering circuit 31 and Threshold circuit 32.
In there is the environment of noise, in the change in time of the measured value being obtained by metering circuit 3, contain noise, therefore preferably remove noise contribution.Filtering circuit 31 is for reducing the circuit of noise contribution of the signal of the measured value Cx that (prevention) obtained by metering circuit 3.Filtering circuit 31 can correspondingly consist of known low-pass filter, bandpass filter with frequency, the intensity of noise contribution.Filtering circuit 31 also can be configured to possesses multistage wave filter.
In addition, the level of the measured value Cx being obtained by metering circuit 3 changes along with environmental baselines such as temperature, humidity, and therefore preferably successive adjustment setting conduct generate the threshold value of the benchmark of detection signal A in testing circuit 410.Threshold circuit 32 is based on above-mentioned filtering signal, to carry out the circuit of setting threshold.For example, Threshold circuit 32 can, by using known computing circuit etc., add that to filtering signal (or deducting) fixing adjusted value carrys out setting threshold.In addition, also can carry out setting threshold by filtering signal being multiplied by fixing adjusted value.The threshold value of utilizing Threshold circuit 32 to set is sent to testing circuit 410.
2. the action of touch sensor
Fig. 7 shows the change of the measured value Cx being obtained by metering circuit 3 and by existing filtering, processes the change of the threshold value of setting.The longitudinal axis is the level of measured value and threshold value, and transverse axis is the time.In the scope of this figure, human body touch detecting electrode 2 three times (a portion), but contain large noise in measured value, so measured value can not surpass continuously (lower than) threshold value reaches the set time, is difficult to sensing touch.In addition, for example, although as long as removing fully noise contribution from the change of measured value can detect touch, produced the lower degradation problem of response (, the tracing ability of threshold value) of touch sensor.
Fig. 4 is for the figure of the action of this touch sensor (1,11) is described, the measured value Cx being obtained by metering circuit 3 while showing human body touch detecting electrode and the change of threshold value (being equivalent to a portion in Fig. 7).At this, measured value Cx shows the change after the noise that utilizes first-order filtering unit (filtering circuit 31) to remove certain limit, is superimposed with in addition periodic noise.In Fig. 4, the periodic table of noise is shown to Tn, will touch detecting electrode 2 during be expressed as period of contact Tt, in (Tc1, Tc2, Tc3), measured value Cx surpasses threshold value during therein three.
As periodic noise, can list alternating current impression noise, below, the situation of the alternating current impression noise (period Tn=17ms) that the source power supply of take by frequency 60Hz causes describes as example.
The judging part 4 of this touch sensor (T.T. sensing cell 41) is obtained the T.T. that the measured value being obtained by metering circuit 3 surpasses threshold value within specified time limit (Tat during object), when Tat is the time more than ratio of stipulating during this T.T. is with respect to object, can be judged as and has approaching or contact of human body.With the size of periodic noise, characteristic Tat during decision objects correspondingly, Tat during this object can be made as to the time over the one-period of noise.The in the situation that of this figure, during object, in Tat, total time (T.T. Tc) that measured value Cx surpasses threshold value is (Tc1+Tc2+Tc3).In Tat during object arbitrarily, T.T. Tc is fixed value when above, and judging part 4 can be judged as the touch that has human body.By judging like this, even if this touch sensor is in the situation that measured value surpasses continuously time of threshold value and shortly also can prevent the undetected survey that touches due to noise.
The in the situation that of above-mentioned alternating current impression noise, for example Tat during object is made as to 55ms (noise periods 3.3 times), when above-mentioned T.T. in 55ms, be 20ms (36% during object, 1.2 of noise periods times) when above, judging part 4 is judged as the touch that has human body.
In addition, except utilizing above-mentioned T.T. sensing of touching of sensing cell 41, the judging part 4 of touch sensor 1 (continuous time, sensing cell 42) can also surpass continuously when threshold value reaches the set time (the second stipulated time) and be judged as and have approaching or contact of human body at the measured value being obtained by metering circuit 3.For example can be made as to the time (being 10ms～20ms left and right) more than cycle of noise above-mentioned the second stipulated time in the situation that producing above-mentioned alternating current impression noise (cycle 17ms).By suitably setting above-mentioned the second stipulated time, can with the having or not independently fast and the stably touch of sensing human body of noise.
For the mode of the action with this touch sensor of easy to understand describes, the situation that microcontroller is formed to touch sensor as center and control according to its program of take is example, and the process flow diagram based on shown in Fig. 6 describes.
Judging part 4 utilizes metering circuit 3 to measure the electric parameters (step S1) corresponding with the electrostatic capacitance producing at detecting electrode 2 places.With the sampling interval of fixing, carry out this step S1 and later processing.
The measured value Cx that importing is measured by step S1 utilizes filter unit to carry out filtering processing, and calculates threshold value (step S2).For example can be by having used the once hysteresis computing of measured value in the past (result that filtering is processed) and this measured value Cx to carry out filtering processing.About the threshold value as judging the benchmark having or not touching, the output that can process filtering is implemented to adjust and is set.
Then, this measured value Cx is compared with the threshold value of setting in step S2, judge whether measured value Cx surpasses threshold value (whether value is lower than threshold value) (step S3).As this measured value Cx, can use by the filtering of step S2 and process the value after the noise of having removed certain limit.
In the situation that measured value Cx does not surpass threshold value, will be initialized as 0 (step S4) continuous time.On the other hand, in the situation that measured value Cx surpasses threshold value, to continuous time with carry out timing (step S5) T.T..Specifically, to continuous time with add that a sampling period upgrades T.T..About T.T., the time that measured value Cx is surpassed to threshold value in time range during object when starting to surpass threshold value adds up to obtain.
Afterwards, by continuous time sensing cell 42 judge whether surpass setting (step S6) continuous time.When surpass setting continuous time, be judged to be and have touch, output proximity test signal S (step S8).
Then, by T.T. sensing cell 41 judge whether T.T. is fixed value above (step S7).In T.T., be fixed value when above, be judged to be to exist and touch, output proximity test signal S (step S8).
Continuous time sensing cell 42 and T.T. sensing cell 41 all do not determine touch in the situation that, turn back to step S1, in sampling timing, by metering circuit 3, measure.
3. the test of the touch-sensing based on T.T.
For confirm by touch sensor as above (1,11) T.T. sensing cell 41 whether can sensing human body touch carried out sensing test.Carry out like that as follows this test: when human body under the state of noise that detecting electrode 2 has been applied to 60Hz 9 touches detecting electrode 2, to measured value Cx measuring T.T. over threshold value in during the object of 55ms.This test findings is as shown in table 1.In addition, measured value Cx detects the current potential of detecting electrode 2 and uses with the sampling period of 1ms to be arranged at the value that the AD converter of metering circuit 3 obtains.
Table 1*IMG[T001]
| The touch time (ms) of actual measurement | T.T. (ms) |
| 40 | 22 |
| 55 | 20 |
| 56 | 23 |
| 69 | 23 |
| 71 | 29 |
| 84 | 28 |
| 86 | 29 |
| 87 | 24 |
| 89 | 20 |
| 107 | 30 |
| 124 | 28 |
As shown in table 1, in the situation that the touch time of actual measurement is 40ms～124ms, during object, in 55ms, measured value Cx is surpassed to the scope that T.T. that time of threshold value adds up to obtain is 20ms～30ms.According to this result, know, in the situation that there is the alternating current impression noise of frequency 60Hz, will during object, be made as 55ms, judgement during this object in measured value Cx over T.T. of threshold value, whether be more than 20ms, the touch of sensing human body reliably thus.
4. comparative example
(1) when by continuous time sensing cell 42 with touch with above-mentioned 3. identical conditions sensing time, measured value Cx in the one-period 17ms of AC noise, have 6ms～7ms during surpass threshold value (with reference to Fig. 7).But can know following content: in the situation that hypothesis measured value Cx surpasses the time of threshold value continuously, be judged to be to exist while surpassing 20ms and touch, utilize continuous time sensing cell 42 sensings less than touch.
(2) in addition, Fig. 8 is illustrated in the identical condition of the comparative example with above-mentioned (1) change of measured value Cx is further strengthened applying the situation that hysteresis filter removes periodic noise.According to this result, know, when touching for the first time, during 10ms, measured value Cx surpasses threshold value greatly, but in the situation that by filtering, processes the change with respect to measured value of the threshold value of calculating tracing ability decline, repeatedly touch and cannot carry out sensing.
According to above test findings and comparative example, know, even if utilizing continuous time sensing cell 42 sensings less than touch in the situation that due to periodic noise, by T.T. sensing cell 41, also can not change the touch of the detection performance ground sensing human body of touch sensor.
In addition, in the utility model, be not limited to above recorded embodiment, can be made as with object, purposes and correspondingly in scope of the present utility model, carry out the embodiment of various changes.
Claims (6)
1. a touch sensor, for detection of approaching or contact of human body, is characterized in that possessing:
The detecting electrode of human body proximity or contact;
Metering circuit, it measures the electric parameters corresponding with the electrostatic capacitance producing at above-mentioned detecting electrode place;
Testing circuit, it is output detection signal when the measured value being obtained by above-mentioned metering circuit surpasses the threshold value setting;
The first timing circuit, it carries out the timing of specified time limit from timing starts;
The second timing circuit, its utilize above-mentioned the first timing circuit carry out timing during, to export the T.T. of the time of above-mentioned detection signal from above-mentioned testing circuit, carry out timing;
Time comparison circuitry, it obtains during the afore mentioned rules that utilizes above-mentioned the first timing circuit timing the fiducial value with the above-mentioned T.T. of utilizing above-mentioned the second timing circuit timing to obtain; And
Value comparator circuit, it will utilize above-mentioned fiducial value and the setting that above-mentioned time comparison circuitry is obtained to compare.
2. touch sensor according to claim 1, is characterized in that,
In the situation that comprise known noise of cycle in utilizing the change of the above-mentioned electric parameters that above-mentioned metering circuit measures, above-mentioned the first timing circuit carries out timing using the time that surpasses the one-period of above-mentioned noise during afore mentioned rules.
3. touch sensor according to claim 2, is characterized in that, also possesses:
The 3rd timing circuit, it will carry out timing from time as the continuous time of the above-mentioned detection signal of above-mentioned testing circuit continuous wave output; And
The second value comparator circuit, it compares above-mentioned continuous time and the second stipulated time of utilizing above-mentioned the 3rd timing circuit timing to obtain.
4. touch sensor according to claim 2, is characterized in that, also possesses:
Filtering circuit, it makes to utilize the composition of the above-mentioned noise in the signal that above-mentioned metering circuit measures to reduce; And
Threshold circuit, it is according to setting above-mentioned threshold value by the signal of above-mentioned filtering circuit.
5. touch sensor according to claim 3, is characterized in that, also possesses:
Filtering circuit, it makes to utilize the composition of the above-mentioned noise in the signal that above-mentioned metering circuit measures to reduce; And
Threshold circuit, it is according to setting above-mentioned threshold value by the signal of above-mentioned filtering circuit.
6. touch sensor according to claim 1, is characterized in that, also possesses:
The 3rd timing circuit, it will carry out timing from time as the continuous time of the above-mentioned detection signal of above-mentioned testing circuit continuous wave output; And
The second value comparator circuit, it compares above-mentioned continuous time and the second stipulated time of utilizing above-mentioned the 3rd timing circuit timing to obtain.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP2012177565A JP5962320B2 (en) | 2012-08-09 | 2012-08-09 | Touch sensor |
| JP2012-177565 | 2012-08-09 |
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| CN203455812U true CN203455812U (en) | 2014-02-26 |
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| CN (1) | CN203455812U (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104898910A (en) * | 2015-05-04 | 2015-09-09 | 联想(北京)有限公司 | Control method and electronic equipment |
| CN106295487A (en) * | 2015-06-25 | 2017-01-04 | 力传扬股份有限公司 | The fingerprint detection method of capacitance type fingerprint sensor |
| WO2018083637A1 (en) * | 2016-11-03 | 2018-05-11 | Vicwood Prosperity Technology Limited | Living body detection method and apparatus |
| CN108917797A (en) * | 2017-05-12 | 2018-11-30 | 商升特公司 | Proximity sensor and method with nonlinear filter |
| CN110521123A (en) * | 2017-03-15 | 2019-11-29 | 利奥波德·科世达责任有限股份公司 | Method for determining the time of contact of capacitive sensor element |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP6194860B2 (en) * | 2014-07-11 | 2017-09-13 | トヨタ紡織株式会社 | Touch sensor |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS60229132A (en) * | 1984-04-26 | 1985-11-14 | Asahi Glass Co Ltd | Touch sensor |
| JP2002100976A (en) * | 2000-09-22 | 2002-04-05 | Gunze Ltd | Capacitance type proximity switch and automatic vending machine using the capacitance type proximity switch |
| KR100982282B1 (en) * | 2008-09-19 | 2010-09-15 | 주식회사 애트랩 | Sensor, sensing method for the sensor, and filter for the sensor |
| JP5558928B2 (en) * | 2010-06-04 | 2014-07-23 | 株式会社ユーシン | Touch sensor |
-
2012
- 2012-08-09 JP JP2012177565A patent/JP5962320B2/en not_active Expired - Fee Related
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Cited By (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104898910A (en) * | 2015-05-04 | 2015-09-09 | 联想(北京)有限公司 | Control method and electronic equipment |
| CN106295487A (en) * | 2015-06-25 | 2017-01-04 | 力传扬股份有限公司 | The fingerprint detection method of capacitance type fingerprint sensor |
| WO2018083637A1 (en) * | 2016-11-03 | 2018-05-11 | Vicwood Prosperity Technology Limited | Living body detection method and apparatus |
| US10819340B2 (en) | 2016-11-03 | 2020-10-27 | Vicwood Prosperity Technology Limited | Living body detection method and apparatus |
| CN110521123A (en) * | 2017-03-15 | 2019-11-29 | 利奥波德·科世达责任有限股份公司 | Method for determining the time of contact of capacitive sensor element |
| CN110521123B (en) * | 2017-03-15 | 2023-05-26 | 利奥波德·科世达责任有限股份公司 | Method for determining the contact time of a capacitive sensor element |
| CN108917797A (en) * | 2017-05-12 | 2018-11-30 | 商升特公司 | Proximity sensor and method with nonlinear filter |
Also Published As
| Publication number | Publication date |
|---|---|
| JP5962320B2 (en) | 2016-08-03 |
| JP2014035705A (en) | 2014-02-24 |
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