JPS5885637A - Touch switching device - Google Patents

Abstract

PURPOSE:To elevate switch sensitivity, and to prevent a malfunction due to noises, by storing a delay amount of an input pulse signal at the time of non- touch to a touch electrode, detecting a delay exceeding this delay amount, and deciding that there is touch to the touch electrode. CONSTITUTION:An input pulse signal A of a prescribed periods that the product of said signal and commercial frequency from a pulse generating means becomes an integer is applied to a deciding a signal outputting circuit 29, and also a inverted signal A' of the signal A is applied to a touch electrode T1 through a CMOS inverter IV27. When no finger touches the electrode T1, an ouput signal B of a CMOSIV28 is further delayed than the signal A by a floating capacity component CX, and its delay amount is counted by a CK storing counter of the circuit 29 by a clock phi. When a finger has touched the electrode T1, a delay amount of the signal B by a touch capacity component CY is counted by another couner of the circuit 29. Each counting amount (n), (m) of the counter is compared by a comparing circuit, and in case of (n)>(m), a deciding signal C is outputted to a deciding circuit 30, and a touch key input signal TK is fetched from the circuit 30.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a touch switch device used as an external input means for W puppy watches, shed electronics, Ni computers, and the like.

Calculators in electronic watches these days? Various built-in so-called calculator watches have been developed. This calculator watch is equipped with a push-button numeric keypad and function keys for inputting numerical values and calculation instructions. However, when a wristwatch is equipped with push-button keys, the appearance of the wristwatch is impaired, giving the impression that the wristwatch is simply being worn on the wrist.

Therefore, it has been considered to use so-called touch switches such as numeric keys and function keys.

In other words, the touch switch is as shown in FIG.

On the top surface of the watch display protective glass (insulating substrate) 1.

A pair of transparent touch electrodes KA, zsv are arranged, and one touch electrode ZAv has a high potential V e (for example,
O volts, connected to logic I [@11) side, t.

Other 7y touch electrode 28 has impedance 16
It is connected to the input side of the CMOS inverter 30 and also connected to a low potential V s m (eg -1.5 volts, logic @"O")@ via a resistor R. Then, when a pair of touch electrodes, 2 people and 2BY human bodies can touch, K is,
What is the potential on the input side of inverter 3?

It is pulled to a low potential V s *@ through a resistor R.

Therefore, the output voltage VowtH of the inverter 3 becomes a high potential level. On the other hand, a pair of touch electrodes 2A.

zBv, as shown in the figure, when touched with a finger, a contact resistance component 2 due to one human body is formed. For this reason.

The input voltage V Aij of the inverter 3 is expressed as a divided voltage by a contact resistance component Z and a resistor R. If the resistance value of the resistor hole is set so as to be equal to or higher than the threshold voltage of the divided voltage inverter 3.

The input voltage of the inverter 3 becomes a high potential level, and the output voltage of the inverter 3 becomes a low potential level. Therefore,
When the output voltage Vout of the inverter 3 is at a low potential level, that is, when the pair of touch electrodes 2B is touched by the human body, it is 1! Turn on the switch again.

The output voltage ■out of inverter 3 is at a high potential level.

In other words, when a pair of touch electrodes are not touched by two people and a 28g human body, the switch turns off.

It can be operated as a switch.

Large variations occur depending on the condition of the rock surface of the person, 2B, the condition of the human body in contact with the external atmosphere, etc.

Therefore, it is necessary to set the resistance of the resistance hole to a large value in advance in accordance with the fluctuation of the IH contact resistance Z.

However, when the resistance value of the tensile resistance R is increased, the switch sensitivity improves and the switch becomes easier to turn on, but on the other hand, noise components to the inverter 3 increase, resulting in malfunction and insulating.

%, the influence of noise due to the frequency of the commercial power supply was significant.

This invention has been made in view of the above-mentioned points, and an object thereof is to provide a touch switch device f which has good switch sensitivity and prevents malfunctions caused by noise.
'The reason is that it is provided to '.

Is this invention below? An example applied to a calculator watch will be specifically explained with reference to FIGS. 2 to 9. FIG. 2 is a schematic diagram of the entire calculator watch. This calculator watch is provided with a touch input section 11 that constitutes a contact capacitance type touch switch that detects the contact capacitance component of one human body. The touch input signal 11 includes a plurality of touch electrodes corresponding to a numeric keypad and a function key, and when a human body touches the touch electrodes, a touch input signal is output and supplied to the input control unit 12. The input side @ section 12 outputs corresponding signals and switch operation signals to each touch switch in accordance with the output of the touch input section 11, and supplies them to the weighing machine section 13Vc. The calculator section 13 is capable of executing four arithmetic operations, etc., in the same way as a normal calculator.

Calculation result data is input from clock section 14 as clock data ζ
n, is supplied to the switching circuit 15. Since the output data of the computer section 13 and the output data of the clock section 14 are switched and displayed on the display section 16 in this switching circuit 15, the switching operation is controlled by the output Q of the trigger flip-flop 17 which is inputted.
and Q.

The output state of the trigger flip 70 knob 17 is inverted in accordance with the pulse signal output from the one-shot circuit 19 every time the manual operation) changeover switch 18 is operated, and its output Q is inverted according to the logic (t[r When I/J, the clock mode can be set to display the output data of the meter display section 16 [clock section 14] on the 1 display section 16.1-
The output Qn of the trigger flip 7a block 17 is given to the one-shot circuit 19 or C-)/<A/x signal 20 to which it is input. 75 Then, summer 1 flip-flop 17F'x one-shot circuit 19
It is reversed at the falling edge of the pulse signal, and when switching from clock mode to computer mode,
20 c-) A one-shot pulse signal is output,
Input fffll 11 Gives input terminal 8Vc of section 12.

23 in FIG. 1 is a pulse generating circuit, which outputs a timing signal to the computer section 13, Vc, and a reference clock signal to the clock section 14. [L pulse generation circuit 23H, 10Hz bar/
The L/S signal A and the 1024 Hz clock signal ρ are generated and output to the input control section 12.

Next, the details of the touch input section 11 and the input side m section 12 will be explained with reference to Figure 3 of VC. first.

The touch input section 11 is constructed as follows. In other words, a numeric keypad is fitted into the front IIR opening of the watch case 21 L: on the top surface K of the display glass 22.

Numerous transparent touch electrodes corresponding to function keys (
In addition, the third! E4 indicates one of the spears, the others are omitted)T
I is placed. In addition, the watch case 21 has a high potential v
Connected to the DD side and placed on the top surface of the 1 display area insulation glass 22.
The number of touch electrodes disposed on the upper surface of the fifth display section protective glass 22 is reduced by half, and is used as the other touch electrode common to a large number of touch electrodes ffi. O in 1 diagram
x is touch electrode T! Cy is the stray capacitance such as the wiring capacitance of the touch electrode T1 and the CMO8IC gate capacitance that always exists between the watch case 21 and the watch case 21.
When the human body is in contact with the touch electrode T1
When the watch case 21 and the touch electricity are in contact with the human body,
This is the contact capacitance component due to the human body that occurs between x and x.

Next, details of the input side # section 12 will be explained. The input control unit 12 receives a 1 ohz pulse signal OA from a generation circuit 23 and a clock e of 1024) IZ. The pulse signal A is eMo8. An N-channel MUS transistor (hereinafter referred to as N-MOB)) and a P-channel #MO8 transistor (hereinafter referred to as N-MOB) are connected in series through 24 IC resistors.

It is connected to each gate input side of the P-MU826 (call it P-MU8), and controls the switching operation of the N-M (J'825) P-MU826.The source side IC of the N-MU825 is connected to the The potential V, s- is supplied by r:, P-MU
826 High potential VDD is supplied via the no-source side Vci and the watch case 21.

CMOS with N-M0825 and )'-MO826
An inverter 27 is configured. And N-MU825
The connection point between and P-MO8ze is connected to the touch electrode TI, and an inverted signal of the pulse signal is supplied via the touch electric body TIKCMO8 inverter 27. It was. CM(
Other CMs based on the output of JS inverter 27 (,) 8
The signal is inverted by being input to the inverter 28. The output signal of this inverter 28 is transmitted to the pulse generating circuit 23.
A pulse signal A and a signal e are inputted from the output signal output circuit M29K. This judgment signal output circuit 29 is configured to output a judgment signal C at a predetermined timing to judge whether or not the watch case 21 and the touch electrode TIK human body are in simultaneous IC contact, and whether there is a touch or not. ing. 1L judgment newsletter/output circuit 2'
The output of the AND gate 20 of the second ceramic is given to the input terminal 8rc of the circuit 9. Judgment signal C is CMOS inverter 2
The output signal of 8 is sent to the judgment circuit 30 which is input as the judgment signal B (P! It detects whether it is in any of the areas and determines whether or not it has been touched.

When it is determined that there is a touch, the touch key human power signal T
It is configured to output K=1 output. In addition.

The I-key input signal TK is sent to the switch input operation circuit of the total switch section 13.

Here, the basic operation of the touch switch device will be explained. First, when the human body is not touching the touch electrode T+, when the pulse signal A output from the pulse generation circuit 23 is at a high potential level as shown in Figure 4, B, CMO
ON, t to N-MU82s that constitutes S inverter 27
P-MO8264-! It becomes OFF. Therefore, the low potential V's becomes the input side potential ripple of the inverter 418 via the N-MO 825. In this case, the negative output signal B of the inverter 18 is affected by the stray capacitance component CX, and the output signal B of FIG.
(Sweet mask off), the rise of the pulse signal is delayed by a length Dx corresponding to the stray capacitance component Cx.

Therefore, when the human body touches the touch electrode TI in the t''+, y,: state, the r&
A contact capacitance component Cy due to the human body is formed on H.

This contact capacitance component Cy is connected in parallel to the stray capacitance component exK:. For this reason, Inno Kuichita 18
In the output signal B of , as shown in B (switch ON) in Fig. 4, there is a long pulse (1) Only that rise will come along with it.

Therefore, the length of the delay corresponding to the stray capacitance component ex is h time) D x v.
If the 1-size 5p signal output circuit 29 is configured so that the judgment signal C is output when the time is slightly overloaded compared to x.

In the determination circuit 30, the 1 determination signal C is applied when it rises.

For these reasons, the judgment 9 signal output circuit 29 and the judgment circuit Rot! , is constructed as shown in FIG. First, in the 1 judgment signal output 1 circuit 29, the one-shot pulse signal supplied to the input terminal S is applied to the S terminal of the R8 type flip-flop 3,1. The Q output of this flip-flop 70 block 31 is applied to the D input terminal of the D-type flip 70 block 32, and the pulse signal A is applied to the clock input terminal CKK of this flip-flop 32.

The rising edge of the pulse signal A in the flip-flop 32 is configured to change. It was 1t. The Ql+1- force of the flip-flop A-tube 32 is applied to the R terminal of the flip-flop 31 and is also heard by the unr gate 33.

The to-be-determined signal B4b is input to this anime game) 33. In addition, the signal to be determined B is input to the D/D gate 35 via the inverter 34, and the clock A41 is input to the D/D gate 35 via the inverter 34.
I'm here. Then, an output signal is outputted from the unytf-)3B at a predetermined timing, and is input to the clock input terminal of the counter 36. A reset terminal KrL pulse signal MA is input to the counter 36, and the content of the spear is reset in synchronization with the rise of the pulse signal -I+. Then, the counter 36 receives the pulse signal A of 11.
+ is at the level, the output B of the NAND 0 gate 35 is counted.Furthermore, the output signal of the NAND 1 gate 33 is input as the clock input terminal CKvc write clock of the 1 yearning counter 37. counter 37Kl
-The count value data of the j counter 36 is lost.

Therefore, the counter 3 obtained by counting at the clock 91
The data mμ that has been stored in the output and storage input link 37 of 6 is sent to the comparison circuit 38.

A comparison is made between their sizes. Comparison #
38! -t Every time the data n in the counter 35 is counted up by 1, it is detected whether the contents of the counter 36 and 37 have reached n)mrc'&;
>Immediately after detecting mVC, 1 judgment signal C? is configured to print. On the other hand.

The signal to be determined B is input to the input terminal 8, and the determination signal C is input to the input terminal CKK.

Sot, Te, 7 Lip Flop 39's Q@output terminal to the stile touch car-human power-II! fTK is taken out.

Next, the operation of the above embodiment will be explained. In the clock mode, the output Q of the flip 7a knob 17 is at the logical value rlJK set to rr. Therefore, the time data t' obtained by the clock section 14 is sent out from the switching circuit 15.
It will be sent to the expression f@16 and displayed. This watch mote °
When the selector switch 18v is operated once, a pulse signal is output from the one-shot circuit 19. At this time, since it is inverted in synchronization with the falling edge of the pulse signal from the flipflop 17 and shot circuit 19,
When the selector switch 18 is operated, a one-shot pulse signal is output from the VC gate 20, and then the switch 1)
Tsu27 C! The output state of the knob 17 is reversed, and the output Q of the knob is set at the computer mode, such as logic value "l".

Therefore, a pulse signal from the Ant 0 gate 20 is output every time the clock mode is switched to the computer mode, and is supplied to the judgment signal output circuit 29 via the input terminal By of the input unit 1# section 120. When this judgment signal output circuit 29 receives a pulse signal from the first gate zO, the flip-flop 31 is set, the Q output becomes a high potential level, and is applied to the D input terminal of the flip-flop 32. When a high potential level is applied to the D input terminal of the flip-flop 32, the flip 70 knob 32 is set in synchronization with the rise of the pulse signal A.

A high potential level signal is output from the Q output terminal (t17 given to the reset terminal of the rib flop 31.

This will reset the f flip 7a knob 31. Also, a signal multiplied by S' is applied to the Q output and applied to the AND gate 33, and this high stomach level signal is used as the next pulse 41I.
It is held and held in the building where person J stands.

Further, at the rise of the pulse fltA from the pulse generating circuit 23, the counter 36 is set to 11, and a counting operation for counting the clock z output from the AND gate 35 is started. However, when the signal to be determined B rises, the output signal of the AND gate 35 becomes a low potential level, so the counting operation of the counter 36 is stopped. At the same time, the output signal of the 1-AND gate 33 goes to a high potential level, and the contents of the counter 36 at the time of the rise of the signal B to be determined are written into the storage counter 37. That's it.

As shown in the timing chart in Figure 6, AND gate 35
The output signal EH of the pulse signal A is output during the period from the rising edge 9 of the pulse signal to the rising edge 9 of the signal to be determined B.
The counter 36 receives the output signal E of the AND gate 35.
Therefore, the content of the counter 36 at the rising edge of the signal B to be determined is rKJ, and this value is stored in the storage counter 37WCIIF. This memory counter 37
The content rKJ written in is the delay of the bowl judgment signal H with respect to the input pressure of the pulse signal due to the influence of the stray capacitance component CX.

In this way, each time the clock mode is switched to the computer mode, the fallout t of the signal to be determined B is written to the storage counter 35, so that the stray capacitance component Cx changes with time or with the environmental atmosphere, etc. 1. Even if you receive a message, you will be responsible for the delay in entering the memory counter 37. The latest is what matters.

Next, the operation of detecting the presence or absence of a touch will be explained.

FIG. 7 is an output waveform diagram of various signals when a human body is not touching the touch electrode TI. First, touch electrode T! In situations where the human body is not in contact with the

Delay th of signal B to be determined with respect to pulse signal AK.

This corresponds to the stray capacitance component ex (see FIG. 7). In this state, the comparator circuit 38
At a point in time when the contents of the storage counter 37 exceed the contents of the storage counter 37, that is, the counter 36 is input with the +th mark a, and the contents of the counter 36 are rK+1 for the contents rKJ of the storage counter 37. When ``f'' is shown in Figure 7,
A determination signal c like this is output. At the 9th point in time when the 1st judgment signal C rises, the judged signal B has already risen as shown in Fig. 7, so the flip-flop 39
The signal to be determined B at a high potential level is input to the D input terminal of the flip-flop 37, and the flip-flop 37 is set in the set state. Therefore, as shown in FIG.
Low potential level touch signal TK from the side output terminal
can be taken out.

Therefore, as soon as the human body touches the touch electrode 1/kTt, the OFF state of the switch is detected.

In addition, FIG. 8 shows the I-electrode T! FIG. 3 is an output waveform diagram of various signals when a human body comes into contact with the device. When the human body is touching the watch case 21, which is worn on the wrist of the watch 2, the user hits the watch as shown in FIG. 3.

When the touch electrode TI is touched with a finger, a contact capacitance component Cy due to the human body is formed between the watch case 21 and the touch electrode T1. Therefore, the control value t of the signal B to be determined relative to the pulse signal person corresponds to the combined capacity of the stray capacitance component (x) and the contact capacitance component Cy (see @8 diagram).2. Similarly to the above case, for the content rKJ of the storage counter 37, the content of the counter 36 is [K+
When tJ is reached, the comparison circuit 38 outputs a judgment 9 signal C as shown in FIG. At the time when the determination signal C rises, the determined signal B does not rise and remains at a low potential level, as shown in FIG.

As a result, the flip-flop 39 enters a reset state, and the high potential level touch key input OK Ao Tk is output from its Q141 output terminal as shown in No. 8-.

Therefore, when a human body comes into contact with the touch electrode T1, (JN of the switch is detected).

In this way, the delay tyir of the signal B to be determined appearing in the pulse signal A caused by the shadow 41 due to the stray capacitance component Cx
- Is the negative value stored in advance, this slow t″L, and whether or not the number 51 B to be judged is slower than the amount?Judge and switch O
Since N, OFF%' is detected, the switch detection operation may be affected by the stray capacitance component C萱.

Next, consider the noise caused by the AC frequency of the commercial power supply ^ VN = A sin 2x self ct ・−・・−
・(1) (A: Con5t) A voltage appears superimposed on the input side heavy pressure of the inverter 28.

Here, the threshold voltage V! of inverter 2B! irises vv t
*= 1 / 2 V n ws t″'t): xt, +(n output BU pulse signal after the person rises.

t=o, 69cRr(sec)...-<2) CtC
After the contact capacitance component and the resistance value of the Rd resistor 24, the output B of the inverter 28 becomes a logical value "1". At this time.

Vmu=V? 11...(3) It is.

Then, the period of the pulse signal A is determined as shown in Figure 8 (, T
If so.

t' e=nT+a...----(4) (rl=0
．． 1.2...-)O≦a (1) The pulse signal can be expressed by the logical value rlJ.

To illustrate the state of this Wc6 formula, it is as shown in Figure 9. In other words, Figure 9 shows an enlarged view of one pulse of the pulse signal person, and due to the influence of the AC frequency of the commercial power supply, the A'A Since the voltage Vh increases and decreases, the potential after 0.6'9(, 'R(seC)) after the pulse signal becomes the logical value "1" is:
As shown by the dotted line in FIG.

It may be above or below 1 pressure Vtg.

Therefore, as shown in FIG. 9, the output signal B of the inverter 28 has variations in its rise, and its pulse width also changes.

In the above equation (5), the term related to the noise due to the AC frequency of the commercial power supply, f, that is, VN = Asin (2 x 1,000 mA c @ n T + #) vc, now fic@T is an integer value. If you take it.

VN=A(1#e=constant), and the pulse width of the output signal B of the inverter 28 shown in FIG. 8 does not change.

ffi, that is, 1 In Japan, the AC frequency of commercial power supply f A
afd, f h c=50Hz I/'+! 60H
Because it is z.

T=1/10 (sec) If , VN is a constant point.

From the above, the sense interval of the contact capacitance component Cy, that is, the period T%-1/1 of the pulse signal -fi+A
0 (16C), it is possible to remove the noise shadow 41 due to the AC frequency of the commercial power source, and the product of the flow wave number is an integer, so the noise shadow due to the AC frequency of the commercial power source *V It can be removed.

In addition, in the above embodiment, the watch case was used as one of the touch electrodes, but the present invention is not limited to this, and for example,
A pair of touch electrodes may be formed on the upper surface of each of the Xs screen protection glasses, and the switch may be turned on by simultaneously touching the pair of touch electrodes with the human body.

Further, although the above embodiments have been described in the case where the present invention is applied to a calculator watch, it goes without saying that the present invention can also be applied to a small electronic calculator.

As explained in detail in more than one T/C, this invention enables the touch switch (JN,
Because it detects OFF operation.

Since the sensitivity of the switch is good, the switch detection operation is reliable, and the noise shadow 411 due to the AC frequency of the commercial power source is removed, malfunctions of the touch switch can be prevented.

[Brief Description of the Drawings] Fig. 1 is a circuit configuration diagram showing a conventional touch switch device; Figs. fvL2 to Fig. 9 show an embodiment in which the present invention is applied to a calculator watch; The overall block circuit diagram of the predictor watch, Figure 3 is the basic circuit configuration diagram of the touch switch device, the timing chart showing the basic operation of the touch switch device, and Figure 5 is the judgment signal output shown in Figure 4. Circuit configuration diagram showing details of the circuit and judgment circuit, Figures f @ 6 to 8 are timing charts showing the operation of the light touch δ inch @ appetizer, and Figure 9 is for explaining the influence of noise due to the AC frequency of the commercial power supply. FIG. 3 is an output waveform diagram of various signals of FIG. 23...Pulse generation circuit, 27.28...C
MO, S inverter, 29...judgment signal output circuit. Tubuflop, Ts...touch electrode. 1st drawing completed Fig. 4, Go to 111-L Fig. 6 Fig. 7 ====-m= Fig. 9

Claims (1)

[Claims] pulse generating means for generating a pulse signal of a predetermined period; a CMO8 inverter to which the pulse signal is supplied as an input signal and also supplies an inverted signal of the pulse signal to the touch electrode; storage means for storing a delay amount of an output signal of the CMOS inverter with respect to a pulse signal from the CMOS inverter;
, a determining means for determining whether an OS first electrode is touched; and a touch switch device in which the period of the pulse signal is expressed as an integer by multiplying the frequency of the commercial power source by V%.