JPH0822361A - Electrostatic inducation type noncontact switch controller - Google Patents

Abstract

PURPOSE:To prevent malfunction due to chattering, temperature variation, etc. CONSTITUTION:This controller is equipped with a judgement reference storage means 24 which stores the 1st frequency and 2nd oscillation frequency, obtained by multiplying the oscillation frequency when a human body is not in contact with a switch element by specific ratios (1-RON) and (1-ROFF), as a switch-ON judgement reference Fi and a switch-OFF judgement reference Gi, a temperature variation detecting means 23, and a judgement reference arithmetic means 26 which detects the frequency of each switch element that the human body is not in contact with and updates the switch-ON judgement reference Fi and switch-OFF judgement reference Gi if it is judged that there is temperature variation after the judgement references are set after the switch element is scanned. Further, if the environmental temperature varies, a reference level is automatically updated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an electrostatic induction type switch which operates by detecting a change in electrostatic capacitance caused by contact with a person.

[0002]

2. Description of the Related Art A non-contact type switch controller utilizing electrostatic induction is provided with a capacitor 30 having a pair of two electrode plates as shown in FIG. The circuit is configured by an on / off judging means including a frequency detection circuit 32 and the like, which converts the change in the oscillation frequency of the oscillation circuit 31 which outputs a pulse signal connected thereto and which changes the frequency.

However, since there is only one criterion for judging that the finger is on and a standard for judging that the finger is off, so-called chattering occurs in which the finger is repeatedly turned on and off in response to unstable movements. As shown in FIG. 9, when the finger W comes into contact with an inaccurate position due to parallax, in addition to the problem that the two switch elements 33 and 34 are turned on at the same time, direct sunlight is also generated. When used in an environment where a sudden temperature change such as hit occurs, there is a problem that the frequency changes regardless of whether or not a finger is touched, resulting in malfunction.

In order to solve such a problem, it is conceivable to use a special material (a liquid crystal filling method) between the switch electrodes or a highly reliable circuit component. There is a new problem that the structure is complicated, the manufacturing process is complicated, and the cost is increased.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object thereof is to provide chattering while an object to be detected is approaching without causing an increase in cost. Another object of the present invention is to provide a highly reliable electrostatic induction type non-contact switch control device that prevents malfunction due to changes in ambient temperature (high temperature, high humidity) and the like.

[0006]

In order to solve such a problem, in the present invention, a plurality of conductors are arranged at regular intervals on the back surface of an insulator to form a plurality of switch elements. An oscillation circuit connected to each of the switch elements of the switch substrate, the oscillation frequency of which changes based on the capacitance of the switch element, and a frequency of the oscillation circuit that depends on the capacitance of the switch element are cyclically output. In the electrostatic induction type non-contact switch control device including a scanning means and an on / off judging means for judging ON / OFF of the switch element by comparing an oscillation frequency of the oscillation circuit with a reference value, each of the switches Predetermined ratio (1-RON), (1-ROF) to the frequency when the human body is not in contact with the element
F) is multiplied by the first frequency and the second oscillation frequency to determine switch-on criterion Fi and switch-off criterion G, respectively.
It is determined that the temperature has changed from the time when each of the determination criteria was set by the temperature change detection means after the scanning of the determination element storage means, the temperature change detection means, and the switch element to be stored as i. In this case, the switching element is provided with a determination reference calculating means for detecting the frequency of the switch element in a state where the human body is not in contact and updating the switch-on determination reference Fi and the switch-off determination reference Gi.

[0007]

[Function] It is determined whether the first frequency and the second oscillation frequency obtained by multiplying the frequency in the state where the human body is not in contact with each switch element by a predetermined ratio (1-RON) or (1-ROFF) are switched on. Since the reference Fi and the switch-off judgment reference Gi are used, the boundary between the switch-on and the switch-off is clarified, and the chattering is prevented by removing the judgment due to the unstable movement of the finger or the uncertain finger position. The switch-on determination standard Fi and the switch-off determination standard Gi are updated corresponding to the temperature change, and the on / off determination is accurately performed even with a rapid temperature change.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the illustrated embodiments. FIG. 1 shows an embodiment of the present invention. In the figure, reference numeral 1 is a non-contact type switch substrate, on which dirt such as hand marks is unlikely to adhere and which can be easily wiped off. On the back surface of the electrically insulating substrate 2 made of tempered glass of about 4 mm, a distance to prevent mutual interference when a specific electrode is selected with a finger, for example, 1 cm in length, 1 cm in width, and 0. Switch elements 3-1 and 3 are provided by providing a plurality of electrodes made of a 5 mm copper plate.
-2 ... 3-N is formed. These switching elements 3-1, 3-2, ..., 3-N are oscillating circuits 4-1 and 4-2, which will be described later with respect to changes in the electrostatic capacitance Cx between the switching elements 3-1 and 3-2 ... 4-3, ... 4-N is configured to be detected as a frequency change.

4-1, 4-2, ... 4-N, and 5 are
In the oscillator circuit, a resistor R is connected between the input and output terminals of the inverter T to output a pulse signal having a frequency matching the capacitance of the input terminal. Each oscillation circuit 4-
Switch elements 3-1 3-2 ... 3-N are connected to the input terminals of 1, 4-2 ... 4-N, and these switch elements 3-1 3-2. And oscillator circuit 4-1 and 4
The sequence number -2, ..., 4-N matches the branch numbers 1, 2, ... Further, the oscillator circuit 5 functions as a temperature detecting means utilizing the change in frequency depending on the ambient temperature, and therefore its input terminal is opened so as not to receive a change in external capacitance. Or a reference capacitor is connected.

These oscillator circuits 4-1, 4-2, ... 4-
N and the operating voltage supply terminal of the oscillation circuit 5 are connected to the decoder 7
The operating voltage V ₀ is connected through the multiplexer 6 that is selectively opened and closed by the pulse signal, and the pulse signal from the output terminal is connected through the multi-digital switch 8 to the signal processing device 10 described later.

Reference numeral 10 denotes the above-described signal processing device, which in this embodiment is a microcomputer comprising a CPU 11, a ROM 12 and a RAM 13, a first output port 1 for outputting a selection signal to a decoder 7 and a multi-digital switch 8.
4 and the respective oscillation circuits 4-1, 4-2, 4-3 ... 4-N,
Timer 1 for setting the count time of pulse signal from 5
5, a counter 15 for detecting the frequencies f1, f2, ... fN, fT of the output signals from the respective oscillation circuits 4-1, 4-2, ... 4-N, 5 and converting them into digital signals, and a finger. The switch element 3 that has been shaken and is determined to be switched on reliably
-1, 3-2 ... 3-N, which outputs the code j of N to a driven device, for example, a plurality of terminals Z1, Z2, Z3 ... ZN
And a second output port 17 provided with.

FIG. 2 shows the functions that the above microcomputer should perform. Each of the switch elements 3-1 and
3-2 ... Oscillation circuits 4-1, 4-2 connected to 3-N,
4-3 ... 4-N and the oscillation circuit 5 are sequentially operated, and the oscillation circuits 4-1, 4-2, 4-3 ,.
Scanning means 21 for taking in frequencies f1, f2, ... fN, fT from -N, 5 and frequencies f1, f2, ... fN, fT sequentially obtained by scanning by scanning means 21 are stored as data Ei. A frequency storage means 22 and a temperature change detection means 23 for detecting the presence or absence of a temperature change using the frequency fT from the oscillation circuit 5 as the temperature detection means as data ET;
A predetermined ratio (1-RON) to the frequency when the human body is not in contact with the switch elements 3-1, 3-2, ..., 3-N,
Judgment standard storage means 24 for storing the first frequency and the second oscillation frequency multiplied by (1-ROFF) as the switch-on judgment standard Fi and the switch-off judgment standard Gi, respectively.
The frequency change rate RON of the oscillation circuit that determines that the finger has come into contact with the switch elements 3-1, 3-2, ..., 3-N, the frequency change rate ROFF that determines that the finger has left, and the rise and fall of the temperature are determined. When the temperature change is detected by the reference data storage means 25 storing the determination reference setting data such as the rate of change RT of the frequency and the temperature change detection means 23, the frequency Ei of the frequency storage means 22 and the reference data storage means 25. Judgment criteria Fi ′ and Gi ′ are calculated based on the above data and are used as new judgment criteria Fi and Gi.
4 is updated, and the oscillation circuits 4-1, 4-2, 4-3, ... Connected to the judgment reference calculator 26 and the switch elements 3-1, 3-2, ... 3-N obtained by scanning. An ON / OFF judging means 27 for judging the ON / OFF of the switch elements 3-1, 3-2 ... 3-N by comparing the frequency Ei of 4-N with the judgment criteria Fi, Gi, and the switch element 3-. 1, 3-
2 ... The number of on-switch elements that stores the number of on-switch elements and the code J when 3-N is determined to be on, and the switch only when the number of turned-on switches is one. The output device 29 is programmed to output the code J of the element to the external device and, when the switch element is turned off, to output a signal indicating the off state to the external device.

Next, the operation of the apparatus thus configured will be described with reference to the flow charts of FIGS. 3, 4 and 5 and the timing chart shown in FIG.

When the power is turned on, the signal processing device 10
Is a decoder 7 based on a clock signal φ having a constant period,
And the code signals A, B, and
C is output to output each oscillation circuit 4-1, 4-2, ... 4-
N and the oscillating circuit 5 are supplied with the operating voltage V ₀ through the multiplexer 6 at a constant cycle for a certain period of time, and each switch 3-
1, 3-2 ..., 3-N oscillator circuits 4-1, 4-2 ,.
The frequency f1 of the pulse output signal output from 4-N,
, fN and the frequency fT of the pulse signal output from the oscillation circuit 5 are read and stored in a predetermined storage area of the RAM 13, that is, the frequency storage means 22 (step M1 in FIG. 3).

That is, each switch element 3-1 and 3-
2, ... 3-N, and the order code i as a switch element assigned to the oscillation circuit 5 is reset (see FIG.
Step S1), the first order code i is output to the first output port 14, the operating voltage supply terminal of the first oscillator circuit 4-1 and the power supply V ₀ are connected by the multiplexer 6,
The oscillation circuit 4-1 connected to the first switch element is turned on (step S2 in FIG. 4), and the multi-digital switch 8 enables reception of the output signal from the oscillation circuit 4-1.

In this state, the timer 15 is started (step S3 in FIG. 4), the counting operation of the pulse counter 16 is started (start S4 in FIG. 4), and the time T ₀ set in the timer 15, for example, 10 msec. When the time has elapsed (step S5 in FIG. 4), the count content of the counter 16 is stored in a predetermined area of the RAM 13, that is, in the frequency storage means 22 as the oscillation frequency Ei of the oscillation circuit 4-1 (FIG. 4).
Step 6).

When the detection of the oscillating frequency of one oscillating circuit is completed, the order code i is incremented (step S7 in FIG. 4), and the above-mentioned steps S2 to S5 for the other oscillating circuits 4-2. The operation of step S7 is executed.

In this way, all switch elements 3
-1, 3-2, ... Oscillation circuit 4-1 connected to 3-N,
4-2, 4-N and RA of the oscillation frequency of the oscillation circuit 5
When the storage in M13 is completed (step S8 in FIG. 4),
Return to main program.

Subsequently, the main program is the switching elements 3-1, 3-2, ... Taken in the sampling routine.
The oscillation frequencies Ei of the oscillation circuits 4-1, 4-2, ..., 4-N connected to the 3-N and the change rates RON and ROFF stored in the ROM 12, that is, the reference data storage means 25 are set to the ON level and the OFF level. Judgment reference frequency level Fi,
A judgment criterion calculation routine (step M3 in FIG. 3) of calculating Gi and storing it in a predetermined storage area of the RAM 13, that is, the judgment criterion storage means 24 is executed.

That is, the order code i of the switch elements is reset as in the sampling routine described above (see FIG. 5).
Step D1), reading the oscillation frequency Ei of the i-th switch element stored in a predetermined area of the RAM 13 by the sampling routine described above, and changing rate RON% corresponding to the preset ON level, that is, In order to determine whether or not the fingertip is approaching, the rate of frequency change from the reference state, that is, the frequency of the state in which the finger is not in contact with the switch element and the state in which it can be determined that the finger touches the switch element (I in FIG. 7) ROM12 of the ratio RON% of
That is, the judgment criterion Fi read from the reference data storage means 25 and set to the ON level by the following formula is calculated as Fi = Ei (1-RON / 100) (step D2 in FIG. 5), and this value Fi is R
A predetermined storage area of the AM 13, that is, the judgment reference storage means 24
(Step D3 in FIG. 5).

Next, the oscillation frequency Ei of the i-th switch element taken in the above sampling routine is set to RAM1.
Read from the predetermined area 3 and change rate ROFF% corresponding to the preset OFF level, that is, the frequency when the finger is not in contact with the switch element and the contact finger is reliably determined to have been separated from the switch element. The judgment criterion Gi for reading the ratio with the frequency in the possible state (II in FIG. 7) from the ROM 12, that is, the reference data storage means 25, and setting it as the OFF level based on the following formula is Gi = Ei (1-ROFF / 100) (step D4 in FIG. 5), and this value Gi is R
A predetermined storage area of the AM 13, that is, the judgment reference storage means 24
(Step D5 in FIG. 5).

Further, the same calculation is executed for the frequency ET of the oscillation circuit 5 to obtain a judgment criterion FT for judging that the temperature has risen and a judgment criterion GT for judging that the temperature has fallen. That is, when the temperature rises, the oscillation frequency fT
As the oscillation frequency fT rises when the temperature drops and the temperature drops, the signs of the rates of change corresponding to the two levels are reversed, and the temperature rise determination reference FT and the temperature drop determination reference GT
Is FT = EN-1 (1-RT%) GT = EN-1 (1 + RT%). Here, the constant RT% is the rate of change of the oscillation frequency due to the temperature change per 1 ° C.

The values of the frequency change rates RON% and ROFF% for judging the approach or retreat of the finger are as follows.
Switch elements 3-1, 3-2, ... 3-N size,
Further, since it depends on the oscillator circuits 4-1, 4-2, ..., 4-N and the elements that constitute the oscillator circuit 5, it is an experimentally required value in advance, but normally RON is about 10%, ROFF
Is about 3% and RT is about 0.007% / ° C.

When the rate of change RON is set small, the sensitivity as a switch is improved and the response is improved, but misrecognition is likely to occur due to the influence of mutual interference, and when it is set large, the operation as a switch is made. Although it is stable, the fingertip must be strongly pressed against the insulator in order to turn on the switch, which deteriorates the operability. Considering these matters, it is desirable to set the above-mentioned about 10%.

On the other hand, since ROFF is for determining switch-off, it is necessary to promptly determine if the finger is slightly separated from the switch element, and therefore, it must be set smaller than RON. .

The greater the difference between RON and ROFF, the greater the effect of preventing chattering.
If it is too large, the switch will not turn off unless the fingertips are sufficiently separated from the insulator, resulting in poor operability. These change rates RON and ROFF need to be appropriately selected depending on the material and thickness of the insulating substrate 2, the size of the conductive plate forming the switch element, the circuit components forming the oscillation circuit, the semiconductor chip, etc. It is desirable to obtain the optimum value by a test after the temperature rises and print it on the ROM 12.

The rate of change RT determines the degree of temperature change for updating the switch-on and switch-off judgment criteria Fi and Gi, and if set small, the frequency of update increases. This is also determined by experiment, but normally, a value of about 0.007% / ° C. is desirable as described above.

The order code i is incremented at the stage when data storage for one oscillation circuit is completed (see FIG. 5).
Step D6), and the operations of steps D2 to D5 are executed again.

In this way, the new judgment criteria Fi ', Gi' of each oscillation circuit 4-1, 4-2, ... 4-N in the current temperature environment are stored as new judgment criteria Fi, Gi. Then (step D7 in FIG. 5), the process returns to the main program.

Next, in the main program, the scanning loop of the switch element is entered, and the same sampling routine as the above-mentioned sampling routine (FIG. 4) is executed this time as a sampling routine for determining the operation of the switch element (FIG. 3). Step M3), whether or not the switch elements 3-1, 3-2, ... 3-N that are turned on, that is, the oscillation circuits 4-1, 4-2 ,. To judge.

That is, the current switching elements 3-1 and
3-2, ... 3-Oscillation circuits 4-N connected to N
, 4-N, and the oscillation frequencies f1, f2, f3, ... Of the oscillation circuit 5 are read in order at a fixed sampling period, and the frequencies f1, f2, f3 ,. That is, it is stored in the frequency storage means 22 (step M4 in FIG. 3).

If there is a switch element that is turned on at the same time, or if there is a switch element that has already been determined to be turned on by checking the flag of the on switch number storage means 28 and that has output a signal to an external device to that effect. To step M
5 and if such a switching element does not exist, the process proceeds to step M6.

(When the switch-on flag is not set) The order code i of the switch elements is reset (see FIG. 3).
Step M6) The scanning is started from the first switch element, and the scanned oscillation circuits 4-1, 4-2, ..., 4-
N and the oscillation frequency Ei of the oscillation circuit 5 are compared with the ON level judgment criterion Fi of the switch i stored in a predetermined storage area of the RAM 37 (step M7 in FIG. 3).

As a result of the comparison, the oscillation circuit 4 sampled
If the oscillation frequency Ei of -1, 4-2, ..., 4-N is smaller than the determination reference Fi (when the fingertip is at the position shown in I of FIG. 7), it is determined to be ON, and this switch element The order code i is stored in a predetermined storage area of the RAM 37, that is, in the on-switch number storage means 28 (step M in FIG. 3).
9), the counter for counting the number of ON switches is incremented once (step M10 in FIG. 3).

By the way, there is a constant deviation Ei × | between the switch-on criterion Fi and the switch-off criterion Gi.
Since RON-ROFF | exists, chattering is prevented without making a determination as to whether the finger is on or off at a halfway position as in III in FIG.

Then, the order code i of the switch element is incremented, and the operations of the above steps M7 to M11 are repeated until the i value matches the order code N of the last switch (step M12 in FIG. 3).

In this way, all the switches 3-
If there is no switch element determined to be ON at the stage when the scanning for 1, 3-2, ..., 3-N is completed (step 13 in FIG. 3), the idle time until the next scanning is used, and Steps M18 and M19 are executed to update the switch-on determination criterion Fi and the switch-off determination criterion Gi, respectively.

That is, when it is determined by the temperature change detection means 23 that the current temperature is changing from the temperature at the time when the determination criteria Fi and Gi are set (step M18 in FIG. 3), the determination reference calculation means 26 , Frequency storage means 22
Switch element stored in the previous scan obtained by 3-
1, 3-2, ... Oscillation circuits 4-1 and 4 connected to 3-N
-2 ... 4-N oscillation frequency Ei and change rate RON stored in ROM 12, that is, reference data storage means 25,
The determination reference frequency levels Fi and Gi which are the ON level and the OFF level from ROFF are calculated and stored in the predetermined storage area of the RAM 13, that is, the determination reference storage means 24 (step M1 in FIG. 3).
Execute 9).

On the other hand, the ON switch number storage means 28 stores the number of switch elements temporarily determined to be in the ON state by one operation.
If the number is 2 or more (step M13 in FIG. 3), the output means 29 is turned on because the finger is applied across the two electrodes (the state shown in FIG. 9). This information is invalidated without specifying the switch element, and the on-switch information is not output to the external device. Then, the process returns to step M3 again to execute sampling. As a result, a malfunction due to an uncertain pressing operation of the switch element is prevented.

On the other hand, when the number of switch elements turned on is 1, it is determined that one switch element is being operated correctly, and the order code i of the switch element is determined.
Is stored in a predetermined storage area of the RAM 13, for example, the ON switch number storage means 28. Then, the output means 29 outputs the order code j of the switch element to one of the output terminals of the output port 17 corresponding to the switch element which is turned on, and sets the switch-on flag (FIG. 3).
Step M14). Then, the process returns to step M3 again, and the switch element which is turned on next is detected.

Needless to say, the signals output from the specific output terminals Z-1, Z-2, ... Z-N of the second output port 17 are input to a device (not shown) connected thereto. , The operation assigned to the pressed switch element will be executed.

(When the switch-on flag is set) When the switch-on flag is set in step M14 and the process returns to the sampling routine again (step M3 in FIG. 3), the switch-on flag is set this time. Therefore (step M4 in FIG. 3), the order code j of the switch element in the ON state is called from a predetermined area of the RAM 13, that is, the ON switch number storage means 28 (step M5 in FIG. 3), and the oscillation circuit connected to this switch element. The oscillating frequency EJ is compared with the off-level judgment reference GJ of the switch element having the order code j stored in the RAM 13 (step M15 in FIG. 3).

As a result of the comparison, when the oscillation frequency EJ is equal to or lower than the off level judgment reference GJ (step M16 in FIG. 3),
It is determined that the finger is still present in the operating region of the switch element or in the vicinity thereof (I or III in FIG. 7), and the process returns to step M3 again. In this case as well, the switch-on flag is still standing (step M4 in FIG. 3), so steps M5 and M15 are executed in the same manner as described above.

As a result of comparison, when the oscillation frequency EJ of the oscillation circuit connected to the switch element exceeds the off-level judgment reference Gi of the switch element of the order code j stored in the RAM 13, ( In step M16) of FIG. 3, the finger W1 (I in FIG. 7) that has been touching the switch element so far retreats from the switch element to II in FIG. 7 and is completely separated, that is, halfway as in III in FIG. It is determined that the switch element is not in the state, the switch-on flag set in the switch element is cleared, and at the same time, the output means 29 causes the terminals Z-1, Z-2, ... Corresponding to the switch of the second output port 17 ... Output a switch-off signal from Z-N.

Then, by utilizing the idle time until the next scan, it is judged whether or not the temperature has changed since the last reference setting (step M18 in FIG. 3), and if there is a temperature change, the switch is turned on. And the switch-off determination criterion Gi are updated (step M1 in FIG. 3).
9).

As described above, when it is detected that all the switch elements are off (step M13 in FIG. 3), the switch-on determination reference Fi and the switch-off determination reference Gi are constantly updated in accordance with the temperature change, Always set a standard that corresponds to changes in the environment and accurately judge whether the switch is on or off.

In the above-described embodiment, the oscillator circuits 4-1, 4-2, ..., 4-N are individually connected to the switch elements, but each switch element is composed of an analog switching element. The same operation can be achieved by connecting one oscillation circuit via the scanning switch, connecting each switching element in turn to the same oscillation circuit, and detecting the oscillation frequency based on the capacitance change of the switching element. It is clear that

Further, in the above-mentioned embodiment, the oscillation circuit 5 to which no switching element is connected is used, and this is used as the temperature detecting means. However, a temperature sensor such as a thermistor or a thermocouple is used, and the signal from this is converted into an analog signal. It is obvious that the same effect can be obtained even if the digital signal is converted into the digital signal by the digital means and is output to the temperature change detecting means 23.

[0049]

As described above, in the present invention, each of the switch elements of the switch substrate in which a plurality of switch elements are formed by disposing a plurality of conductors at regular intervals on the back surface of the insulator is provided. An oscillating circuit that is connected and has an oscillating frequency that changes based on the capacitance of the switching element, a scanning unit that cyclically outputs the frequency of the oscillating circuit based on the capacitance of the switching element, and an oscillating frequency of the oscillating circuit and a reference. In an electrostatic induction type non-contact switch control device equipped with an ON / OFF judging means for judging ON / OFF of a switch element by comparing it with a value, a predetermined frequency is set in a state where a human body is not in contact with each switch element. Ratio of (1-RON), (1-R
OFF) is multiplied by the first frequency and the second oscillation frequency as the switch-on determination reference Fi and the switch-off determination reference Gi, respectively, a determination reference storage means, a temperature change detection means, and after the scanning of the switch element is completed. If the temperature change detection means determines that the temperature has changed since the determination criteria were set, the frequency of each switch element in the state where the human body is not in contact is detected to determine the switch-on determination criteria Fi, Also, since the switching-off determination reference Gi is provided with the determination reference calculation means, it is possible to clearly distinguish the ON level and the OFF level from each other to prevent chattering due to unstable finger movement, and to use two switch elements. It is possible to prevent signal output due to inaccurate operation such as straddling, and to automatically update the reference level when the environmental temperature changes, which is reliable. It makes it possible the high-switch operation. For this reason, in order to make it usable outdoors, the thickness of the insulating substrate is increased so that the frequency change caused by the contact of the human body is small, and a large number of switch elements are used in an extremely narrow area such as a portable device. Can be operated with a high degree of reliability even when it is arranged.

[Brief description of drawings]

FIG. 1 is a block diagram of an apparatus showing an embodiment of the present invention.

FIG. 2 is a block diagram showing functions to be performed by a microcomputer in the same apparatus.

FIG. 3 is a flowchart showing a main operation of the same apparatus.

FIG. 4 is a flowchart showing a sampling operation of the above apparatus.

FIG. 5 is a flowchart showing a judgment reference calculation operation of the above apparatus.

FIG. 6 is a timing chart showing the operation of the above apparatus.

FIG. 7 is a diagram schematically showing judgment criteria in the same apparatus.

FIG. 8 is a diagram showing an example of a conventional static induction type non-contact switch control device.

FIG. 9 is a diagram showing a cause of malfunction of a conventional device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electrostatic induction type switch panel 2 Electric insulating substrate 3-1, ... 3-N switch element 4-1, 4-N Oscillation circuit 5 Oscillation circuit 6 Multiplexer 10 Signal processing device 20 Functions realized by microcomputer

Claims (4)

[Claims] 1. A capacitance of the switch element, which is connected to each of the switch elements of a switch substrate on which a plurality of switch elements are formed by disposing a plurality of conductors on the back surface of an insulator at regular intervals. An oscillation circuit whose oscillation frequency changes based on the above, scanning means for cyclically outputting the frequency of the oscillation circuit due to the capacitance of the switch element, and comparing the oscillation frequency of the oscillation circuit with a reference value. In an electrostatic induction type non-contact switch control device equipped with an ON / OFF judging means for judging ON / OFF of a switch element, a predetermined ratio (1- RON), (1-ROFF) multiplied by the first frequency and the second oscillation frequency as the switch-on determination standard Fi and the switch-off determination standard Gi, respectively. The temperature change detecting means and the human body of each switch element when the temperature change detecting means determines that the temperature has changed from the time when each of the determination criteria is set after the scanning of the switch element is completed. An electrostatic induction type non-contact switch control device comprising a judgment reference calculation means for detecting a frequency in a non-contact state and updating the switch-on judgment reference Fi and the switch-off judgment reference Gi. 2. The electrostatic circuit according to claim 1, wherein an oscillation circuit is individually connected to each of the switch elements, and the temperature information of the temperature change detecting means is a frequency of the oscillation circuit to which the switch element is not connected. Inductive non-contact switch control device. 3. The electrostatic induction type switch control according to claim 1, wherein the judgment reference calculation means operates when there is no newly turned on switch element by the step of detecting whether the switch element is on or off. apparatus. 4. The RON is about 10%, and the ROFF is
Is about 3%, The static induction type non-contact switch control device according to claim 1.