JPH0226827B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a touch switch device used as an external input means for electronic wristwatches, small electronic calculators, and the like.

Recently, various so-called calculator watches, which are electronic wristwatches with a built-in calculation function, have been commercialized. If the numeric keypad and function keys of this calculator watch are push-button keys, the appearance of the watch will be impaired.

Conventionally, it has been considered to configure the numeric keypad and function keys with so-called touch switches, as shown in FIGS. 1 and 2. That is, in this type of watch, a plurality of touch electrodes b _{1 to bn corresponding to the numeric keypad and function keys are arranged on the upper surface of the display protective glass a on the front surface of the watch, and a plurality of touch electrodes b 1} to bn corresponding to the numeric keypad and function keys are arranged below the display protective glass a. Each touch electrode b ₁
I am trying to display ~bn functions.

However, when a large number of touch electrodes are arranged in a small electronic device such as a wristwatch, the size of the touch electrodes and the mutual spacing between adjacent touch electrodes become extremely small. Therefore, as shown in FIG. 3, if you try to touch the touch electrode b ₁ corresponding to the display D ₁ while viewing the display D ₁ of the liquid crystal panel c from diagonally above, the display position of the liquid crystal display panel c and the touch Due to visual misalignment with the electrode installation position,
Even if you touch the displayed area accurately, you will also touch other adjacent touch electrodes at the same time. for example,
As shown in Figure 4a, when you touch the numeric keypad □5, the position of your finger shifts downward, and when you touch it with your right hand, it shifts to the right, and when you touch it with your left hand, it shifts to the left. This causes the user to simultaneously touch not only the desired numeric keypad □5 but also the numeric keypad □6 on the right side, the numeric keypad □2 on the lower side, and the numeric keypad □3 diagonally lower to the right.
In such a case, it may be possible to switch only the one with the largest contact area between the touch electrode and the human body, but the contact area is determined by the desired contact area between the touch electrode and the human body, as shown in Figure 4b. It doesn't necessarily have to be the largest area.

The present invention has been made in view of the above circumstances, and its purpose is to provide the desired touch electrodes even when a human body accidentally touches multiple touch electrodes adjacent to each other at the same time. To provide a touch switch device which prevents erroneous operation of switch input by operating only a touch switch.

Hereinafter, an embodiment in which the present invention is applied to a calculator watch will be described in detail with reference to FIGS. 5 to 14. FIG. 5 shows the overall block circuit diagram of the calculator watch. On the top surface of the display protective glass 2 attached to the watch case 1, there are numeric keys and function keys.
Sixteen touch electrodes T ₁ to T ₁₆ are arranged. These 16 touch electrodes T ₁ to T ₁₆ are arranged as shown in FIG.

Figure 6 shows 16 as the names of touch electrodes T ₁ to _{T 16} .
The hexadecimal numbers "0", "1", "2"..."9", "A" from the top left in the figure correspond to single digit numbers in decimal.
,
They are represented by numbers "B"..."F".
From now on, in order to distinguish between hexadecimal numbers and decimal numbers, the sign S is added to the hexadecimal numbers and they are written as $0, $1, $2...$A, $
B... shall be expressed as $F. Corresponding to Fig. 1, the touch electrode of numeric keypad □7 is numbered $0, the touch electrode of numeric keypad □8 is numbered $1,
The touch electrode of the numeric keypad □3 can be represented as the number $A.

In FIG. 5, each touch electrode T ₁ to _{T 16} is connected to a sense circuit 4 constituting the touch sensor section 3, respectively. This touch sensor section 3 is composed of a sense circuit 4 and a control circuit 5, and includes touch electrodes.
The contact capacitance component when a human body contacts T ₁ to T ₁₆ is detected corresponding to each of the touch electrodes T ₁ to T ₁₆ , respectively.

Here, details of the touch sensor section 3 will be explained with reference to FIGS. 7 to 9. FIG. 7 shows a basic configuration diagram. In the figure, 4-1 is a CMOS inverter, and N-channel MOS transistors (hereinafter referred to as N
-MOS) 4-1A and P channel MOS
Transistor (hereinafter referred to as P-MOS) 4-
The gate electrode of 1B has a predetermined period (for example, 16
Hz) rectangular wave X is input. And N-
One ends of the MOS 4-1A and the P-MOS 4-1B are connected to each other via a CMOSIC tensile resistor 4-2. In addition, low potential V _SS is supplied to the other end of N-MOS4-1A, and P-MOS4-
High potential V _DD is connected to the other end of 1B via watch case 1.
is supplied. And P-MOS4-1B
The connection point between and the tensile resistor 4-2 is the touch electrode T ₁
is connected, and CMOS inverter 4
-3 is connected to the input side. This switch 4-3
The output B of the other inverter 4- connected in series is
4 and is inverted. This inverter 4-
The output of 4 is supplied to an AND gate 4-5 to which the rectangular wave X is input. This and gate 4-
The output Y of 5 is a determined signal used to determine whether or not a human body has touched the touch electrode _T1 . In addition, Cx in the figure is a stray capacitance component,
The wiring capacitance caused by the wiring of touch electrode _T1 ,
This is caused by natural phenomena such as gate capacitance caused by the high input impedance of the CMOSIC gate. In addition, in the figure, Cy indicates the touch electrode when the human body is in contact with the watch case 1.
This is a contact capacitance component caused by the human body that occurs between the watch case 1 and the touch electrode T ₁ when the human body touches T ₁ .

Therefore, when the human body is not touching the touch electrode _T1 , the CMOS inverter 4-1
When the square wave X shown in the figure is input, N-MOS4
-1A is ON and P-MOS4-1B is OFF.
Therefore, the low potential V _SS is input to the input side of the inverter 4-3 via the N-MOS 4-1A.
At this time, the output B of the inverter 4-3 is due to the time constant of the stray capacitance component Cx and the tensile resistance 4-2.
As shown at B (switch OFF) in FIG. 8, the rise of the rectangular wave X is delayed by a length (Dx) corresponding to the stray capacitance component Cx.
Therefore, the output Y of the AND gate 4-5 is
As shown by Y (switch OFF) in the figure, the pulse width becomes a rectangular wave equal to the delay amount Dx.

Next, when the touch electrode T ₁ is touched by the human body, a contact capacitance component Cy due to the human body is formed between the touch electrode T ₁ and the watch case 1 . This contact capacitance component Cy is connected in parallel to the stray capacitance component Cx, so the output B of inverter 4-3
As shown in B (switch ON) in Figure 8, the stray capacitance component Cx and the contact capacitance component for the rectangular wave
Length corresponding to the combined capacitance component with Cy (Dx + Dy)
However, its rise will be delayed. Therefore, the output Y of the AND gate 4-5 is Y in FIG.
As shown by (switch ON), the pulse width becomes a rectangular wave equal to the delay amount Dx+Dy.

The sense circuit shown in Figure 9 consists of 16 touch electrodes.
T ₁ to T ₁₆ ($0 to $F) are specified in a time-division manner, and rectangular waves Y corresponding to the touch electrodes T ₁ to _{T 16} are sequentially output. That is, 4-bit signals a to d are inputted from the control circuit 4 to this sense circuit. These 4-bit signals a to d are used to selectively designate each touch electrode T ₁ to _{T 16} sequentially, and each signal a to d is weighted with "1", "2", "4",
If "8" is added, the 4-bit data becomes 16
Touch electrodes T ₁ , T ₂ , T ₃ . . . T ₁₆ correspond to numbers $0, $1, $2 . . . $F expressed in base numbers. When these signals a to d are input to the decoder 4-6, the decoder 4-6 outputs signals "1" to "16" corresponding to the input 4-bit data, and the corresponding transmission Supplied to gates _G1 to _G16 . This transmission gate G ₁ ~
For G ₁₆ , the corresponding signal “1” to “16” is high potential V _DD
It is turned ON when the level is on, and one end thereof is connected to the corresponding touch electrodes _T1 to _T16 , and the other end is connected to the connection point of inverters 4-1 and 4-3. Therefore, each transmission gate _G1 to _G16 , when alternatively turned on sequentially, connects the touch electrode _T1 to the inverters 4-1 and 4-3.
Connect to the connection points in time division. Therefore, rectangular waves Y corresponding to the touch electrodes T ₁ to _{T 16} are sequentially outputted from the AND gate 4 - 5 and supplied to the control circuit 5 .

As shown in FIG. 5, the control circuit 5 is supplied with control pulses O/ ₁ to O/ ₃ generated and outputted by the pulse generation circuit 6 and a pulse width count signal fc, respectively. As shown in FIG. 11, the control pulses O/ ₁ to O/ ₃ are three-phase signals with different phases, and their frequency is, for example, 512 Hz. Further, the pulse width count signal fc is a signal for counting the pulse width of the rectangular wave Y, and its frequency is, for example, 524288 Hz.

The control circuit 5 is constructed as shown in FIG. That is, the control circuit 5 has a 5-bit up counter 5-1. This up counter 5-1 has its clock input terminal.
The control pulse _O1 input to CK is frequency-divided and signals A to E (see FIG. 11) are output from the output terminals of each bit. The output of this most significant bit, i.e.
Signal E is a 16Hz signal, and the corresponding signals A to D
is applied to the AND gates 5-2 to 5-5 to which the control pulse O2 is input, and is applied to the AND gate 5-6 to which the control pulse _O2 is input. And gate 5-
2 to 5-6 are the corresponding signals a to d at 1/16 sec intervals,
It outputs a control pulse O ₂ (see Figure 11), and this output is given to the sense circuit 4, which connects 16 touch electrodes at intervals of 1/32 seconds.
Make the user repeatedly perform the sensing motion.

In addition, the control pulse _O1 is applied to the up counter 5-7.
is applied to the clear terminal CLR to clear its contents. Further, the control pulse O ₃ is applied to the AND gate 5-8 to which the signal E is input, causing the AND gate 5-8 to output a signal O ₃ ' (see FIG. 11). This signal _O3 ' is applied to the clock input terminal of latch 5-9 to which each bit output "1", "2", "3"..."K" of up counter 5-7 is input.
CK, the output contents of the up counter 5-7 are stored in the latch 5-9, and the signals a to
4-bit latch 5-1 to which d is input
0 clock input terminal CK, and the signal a~
The contents of d are stored in latch 5-10. The up counter 5-7 counts the output of the AND gate 5-11 (the AND of the signal Y to be determined and the pulse width count signal fc) input to its clock input terminal CK, and calculates the pulse width of the signal Y to be determined. It converts the width into a digital value (binary number), and the counted value data of the up counter 5-7 corresponds to the delay amount Dx when the human body is not touching the touch electrode sensed by the sense circuit 4. Moreover, when it is touched, it corresponds to the delay amount Dx+Dy. Therefore, the delay amount is stored in the latch 5-9 in synchronization with the signal _O3 ', and the numbers $0 to $F of the touch electrodes being sensed by the sense circuit 4 are stored in the latch 5-10. be remembered. Note that the output content of the latch 5-9 is x, and the output content of the latch 5-10 is n.

On the other hand, the signal E is applied to the clock input terminal CK of a delay type flip-flop (hereinafter referred to as D-FF) 5-12. The delay input terminal D of this D-FF5-12 has a
When the AC switch S is turned on, a high potential V _DD is supplied as its operation signal, and the operation signal of the switch S is latched to the D-FF5-12 at the rising edge of the signal E. Therefore, when the AC switch S is operated once, the output Q
becomes “1” and is output as a signal AC. Note that this signal AC is a signal for storing the delay amount Dx for the stray capacitance component of each touch electrode in a predetermined memory in advance.

Next, another circuit configuration shown in FIG. 5 will be explained. The output data of the control circuit 5 is supplied to the input port 8 of the data processing device 7. This data processing device 7 has a CPU (central processing unit) 9, a ROM (read only memory) 10, a RAM (random access memory) 11, and an output port 12, each of which is connected via a bus line. It is connected. Note that the output of the output port 12 is sent out as a switch signal.

Thus, the data processing device 7 is configured to be able to execute the following four processes. That is, first, a preset process in which the delay amount Dx for the stray capacitance component of each touch electrode is written and stored in advance in the RAM 11 for each touch electrode, and second, a switch selection process in which only a desired touch switch is selected and switched. , thirdly, touch sensitivity automatic adjustment processing, and fourthly, processing against changes over time.

First, the first process can be executed as follows. That is, when the signal AC sent from the control circuit 5 is "1", the RAM 11
When AC switch S is turned on, a write designation is received. Further, addresses of the RAM 11 are sequentially designated according to data n (touch electrode number) sent from the control circuit 5. However,
When the AC switch S is turned on, assuming that the touch electrode is not touched by the human body, the data x sent from the control circuit 5 becomes the delay amount Dx with respect to the stray capacitance component of the touch electrode. This data x
The data is sequentially written and stored at designated addresses in the RAM 11. That is, the RAM 11 has storage areas corresponding to 16 touch electrodes, and each storage area stores data x ₁ , x 2 , x ₂ corresponding to 16 touch electrodes.
x ₃ , . . . x _F are written and stored as shown in FIG. At the same time, data x ₁ is stored in RAM11,
It has storage areas corresponding to x ₂ , x ₃ , . . . x _F , and the data y ₁ ,
y ₂ , y ₃ , ...y _F are written and stored. That is,
The data processing device 7 now considers the data x for the n-th touch electrode as xn, the data y as yn, and also considers the fluctuation of the stray capacitance component, the counting error ±LSB in the up-down counter 5-7 of the control circuit 5, etc. , ε = 2 to 3, execute yn = xn (AC: ON) + ε ((xn (AC: ON) is the value of data xn when AC switch S is turned on)) and set the specified value in RAM 11. It is designed to be stored in the memory area.

In this way data x ₁ ~ x _F , y ₁ ~ y _F are stored in RAM
11 and then touch the touch electrode with the human body, the data processing device 7 executes the calculation of the following equation and stores the data t ₁ , t ₂ , t ₃ . . . t shown in FIG. Write and memorize _F.
That is, if the n-th data t is tn, then t _o = x _{o (AC} : _OFF) - y _o This value of t _o is the above delay amount Dy for the contact capacitance component when the human body contacts the touch electrode. .

Next, the second process described above can be executed as follows. The data processing device 7 first processes the contact capacitance component (data) obtained corresponding to each touch electrode.
t _o ), the touch electrode with the maximum contact capacitance component is detected. If this touch electrode is used as a reference touch electrode and its designated number is m, then (1) If Jt _n-1 −t _n <0, then r←m Jt _n-1 −t _n ≧0, then r←m _-1 ( J: constant). That is, select the touch electrode m _-1 adjacent to the left side of the reference touch electrode m for the maximum contact capacitance component, multiply the contact capacitance component of this touch electrode m _-1 by a constant J, and calculate the difference between that value and the maximum contact capacitance component. The magnitude is compared, one of the touch electrodes m and m-1 is selected according to the comparison result, and processing is performed to select it as r.

Next, the data processing device 7 executes the following calculation: (2) If KJt _r-4 −t _r <0, S←r If KJt _r-4 −t _r ≧0, S←r-4 (K: constant) do. That is, select the touch electrode r-4 adjacent to the upper side of the touch electrode r selected in the above process, multiply the contact capacitance component of this touch electrode r-4 by a constant K, and calculate the value and the touch electrode r.
Compare the magnitude with the contact capacitance component of and select one of the touch electrodes r and r-4 according to the comparison result,
Processing is executed to set it as S. This touch electrode S becomes the finally selected touch electrode.

The above processing will be specifically explained with reference to FIG. Fig. 13 shows that when trying to touch touch electrode $5, touch electrode $6, which is placed next to it, is mistakenly touched.
When $A is also touched, the value of the contact capacitance component (data _to ) obtained corresponding to each touch electrode is shown. In this case, assuming constants J=1.5 and K=2, first, touch electrode m having the maximum contact capacitance component is touch electrode $A, and m=$A.

Next, Jt _n-1 −t _n =1.5×48−51 =21≧0, so r=$9 is selected.

Next, since Ktr _-4 −t _r =2×32−48 =16≧0, S=$5 is selected.

Therefore, touch electrode $5 was finally selected. In this case, constant J=1.5, K=
The reason why it was set as 2 was due to the visual discrepancy between the display position of the touch electrode and the function display position of the touch electrode.
This takes into consideration the possibility that even if you touch the displayed area accurately, the touch position will touch other adjacent touch electrodes at the same time, and the amount of touch position deviation is generally larger in the upward direction than in the horizontal direction. Since the amount of deviation is large, the constant K is set to a larger value than J. The amount of deviation in the touch position varies depending on the user's habits, the pitch of the touch electrode, etc., but it can be accommodated by appropriately selecting the constants J and K. Note that the constant J is the leftward shift selectivity, and the constant K is the upward shift strength.

Here, the above formula (1) cannot be implemented in the case of touch electrodes $0, $4, $8, and $C where no touch electrode is adjacent to the left side, and the above formula (2) cannot be implemented when the touch electrodes are not adjacent to each other on the left side. Touch electrodes with no adjacent electrodes $0, $1, $2,
In the case of $3, it is not possible. Therefore, in such a case, the calculation of the above formula is executed. That is, the touch electrode m with the maximum contact capacitance component
When the touch electrodes $0, $4, $8, $C, r=m regardless of the above equation (1), and the selected touch electrode r is the touch electrodes $0, $1, $
2. When $3, S=r is set regardless of the above equation (2). Note that the data m is stored in a predetermined storage area of the RAM 11 as shown in FIG.

Next, the third process described above can be executed as follows. In other words, the data processing device 7 senses each of the 16 touch electrodes and processes each data.
t _o is compared with data △, and if there is at least one touch electrode where t _o >△, it is determined whether the touch electrode has touched.
This data △ is the touch sensitivity, for example, K
In determining the presence of a touch for the first time, let M be the maximum value of the data t _o up to that point, execute △=dM (0≦d<1), and use this value as K + the data △ for determining the presence of a touch for the first time. It has come to be used as a In this way, each time the presence of a touch is determined, a new sensitivity is determined to be used in the next determination of the presence of a touch. This is done in order to improve switching stability and operability by setting the sensitivity to match the surface condition of the touch electrode, the condition of the human body being touched (perspiration rate, hardness), the environmental atmosphere (temperature, humidity), etc. It is. Note that when K=0, Δ=0, and the first touch determination is made at the highest degree. Further, the sensitivity data Δ is stored in a predetermined storage area of the RAM 11 as shown in FIG.

Next, the fourth process described above can be executed as follows. Since the contact capacitance component changes over time, it takes time for it to stabilize. For this reason, the data (t _o ) obtained immediately after touching the touch electrode is unstable. Therefore, the switch selection of the second process is executed after a certain period of time has elapsed since it was first determined that there was a touch, and the data had stabilized. In other words, the determination of touch is e
When the process continues (e≧2) times, the switch selection process is executed for the first time. If the touch detection number e is increased, the above data will be stabilized, but the time from touching the touch electrode to turning on the touch switch will become longer, and if the limit for the feeling of use is about 1/4 second. In addition, the value of e is set to be approximately 2 to 4. Furthermore, the data e is
It is stored in a predetermined storage area of the RAM 11 as shown in FIG.

Next, the operation of the data processing device 7 will be explained with reference to the flowchart of FIG. When the power is turned on, an initial set (initial value setting) subroutine (INIT) is executed in step S1.
This subroutine proceeds to a data reading subroutine (DATA) at step SA1, and sequentially executes steps SB1 to SB3. That is,
Data n, x, AC sent from control circuit 5
In step SB1, data n is read, in step SB2, data x is read, and in step SB3, data AC is read and stored in a predetermined storage area of the RAM 11. Next, the process proceeds to step SA2 of the initial reset subroutine, and it is determined whether the AC switch S is turned on or not, depending on whether the data AC is "1" or "0". Here, when the AC switch S is ON, that is, when the data AC is "1" and it is determined as "YES", the process proceeds to the next step SA3. This step SA3 executes a process of calculating "x _o +ε" and writing this calculation result data into a predetermined storage area of the RAM 11 as data y _o . Next, the process proceeds to step SA4, where the sensitivity data Δ is set to "0" and set to the highest sensitivity. Next, step SA5
After executing the data reading process of the subroutine, the process moves to step SA6. Here, it is determined whether the AC switch S is turned on or not in the same manner as in step SA2, and when the determination is ``YES'', steps SA3 to SA6 described above are repeatedly executed. In this case, when the AC switch S is turned on once, the AC switch S is turned on at least while the sense circuit 4 senses the 16 touch electrodes once.
Since it is in the ON state, step SA3 to
By repeatedly executing SA6, data x ₁ to x _F and y ₁ to y _F for each touch electrode are obtained.
The data is written to a predetermined storage area of the RAM 11. As a result, data x ₁ ~ x _F representing the delay amount of the stray capacitance component corresponding to each touch electrode, and this data x ₁ ~
Presetting of data y ₁ to y _F obtained by adding the value of ε to x _F is executed. If the answer is NO in step SA6, the process returns to the main routine and returns to step S2.
This step S2 executes a process of transferring the touch detection count e to a predetermined register U. continue,
By executing step S3, the process advances to a subroutine (TOUTH) for determining whether there is a touch.

In executing step SC1 of this subroutine, the maximum value data M of the contact capacitance component is stored.
A process of transferring data "0" to a predetermined storage area of the RAM 11 and clearing its contents is executed.
Next, the program advances to step SC2 and executes a subroutine (READ). Step SA5 of this subroutine executes the subroutine (DATA),
Data n, x, AC sent from control circuit 5
Load. Then proceed to the next step SA6,
Executes whether or not AC switch S is turned on. Here, AC switch S is turned off, so the next step of the subroutine (TOUCH)
Proceed to run SC3. This step SC3 is RAM1
A process is executed in which the data x _o and y _o stored in the RAM 11 are read out, y _o is subtracted from the data x _o , and the subtraction result data is written as data _to in a predetermined storage area of the RAM 11 . As a result, the contact capacitance component corresponding to each touch electrode is determined. This data _to is compared in magnitude with the sensitivity data △ in the next step SC4, and it is determined that t _o >△. Here, _to
If there is at least one touch electrode that is >△, it is determined that there is a touch. Now, when no touch electrode is touched, _to is set to "0", or when the first touch is judged, data △ is set to the highest sensitivity "0", so in this case, in step SC4, The answer is “NO”. Also, if step SC4 is determined to be ``YES'', the next step is
Move on to running SC5. This step SC5 is data <sub>to</sub>
and data M, and determines whether t <sub>o</sub> > M. When it is determined as "YES", that is, it is determined that the data t <sub>o</sub> just obtained is larger than the maximum value M up to that point. Occasionally, proceed to the next step SC6. This step SC6 executes a process of writing <sub>data</sub> to into a predetermined storage area of the RAM 11 as M and data n as m, thereby updating the contents of data M and m. Next, the process proceeds to step SC7, where it is determined whether the data n is the touch electrode $F, in other words, whether one round of processing for the 16 touch electrodes has been completed. This step SC7 is a step
It is also executed if SC4 and SC5 are determined to be "NO". Then, in step SC7,
When the answer is "NO", that is, when it is determined that the processing for the 16th touch electrode $F has not been completed, the process returns to step SC2, and steps SC2 to SC7 are repeatedly executed. Further, if the determination at step SC7 is "YES", the process advances to the next step SC8, where it is determined whether the data M is greater than "0". In this case, when the human body is touched by even one of the 16 touch electrodes, it is determined as ``YES'', and the process proceeds to the next step SC9, where a process of transferring data M to a predetermined register D is executed. If all the touch electrodes have not been touched, "NO" is determined at step SC8, and the process proceeds to the next step SC10, where a process is executed to turn off the switches for all touch electrodes. However, step SC9 or
When the process of SC10 is completed, the process returns to the main routine and executes step S4.

In this step S4, similarly to the above-mentioned step SC8, a judgment is made as to whether or not M>0, and the result is "NO".
When it is determined that this is the case, the process returns to step S2 and steps S2 to S4 are repeatedly executed. “YES” again
When it is determined that this is the case, the process proceeds to the next step S5, where "1" is subtracted from the contents of the register u in which the number of times of touch detection is stored, and the subtraction result data is transferred to the register.
Next, the process moves to step S6 to determine whether the contents of the register u are u = 0, that is, the number of times e to determine if the subroutine (TOUTH) has been touched is determined.
It is determined whether or not the
When it is determined that this is the case, the process returns to step S3 and steps S3 to S6 are repeatedly executed. If the answer is ``YES'', the process moves to the next step S7 to execute the subroutine (KEYON).

In executing step SD1 of this subroutine, it is determined whether m=L and whether data m is touch electrode number $0, $4, $8, $C. Here, if the determination is "NO", the process moves to the next step SD2. This step SD2 executes the operation Jt _n-1 -M and transfers the resultant data to a predetermined register A. continue,
Proceed to step SD3 and the contents of register A are A≧0.
Execute the judgment as to whether or not. "YES" here
If it is determined that this is the case, the process proceeds to step SD4, where data t _n-1 is transferred to a predetermined storage area of the RAM 11 as data M and data m-1 as data m.
Next, the process moves to step SD5, where it is determined whether m=v, that is, whether data m is the touch electrode number $0, $1, $2, $3. This step SD5 is also executed when it is determined ``YES'' in step SD1 and ``NO'' in step SD3. If the answer is NO at step SD5, the process moves to the next step SD6, where the calculation Kt _n-1 -M is executed and the resulting data is transferred to a predetermined register B. Next, the process proceeds to step SD7, where it is determined whether the contents of register B are B≧0. If the answer is “YES”, the step
Proceed to SD8, data t _n-4 to data M, data m-
4 is transferred to a predetermined storage area of the RAM 11 as data m. Next, the process proceeds to step SD9, where a switch signal for the touch electrode indicated by the content of data m is output, and the switch for the touch electrode is turned on. This step SD9 is also executed when it is determined ``YES'' in step SD5 and ``NO'' in step SD7. Therefore, the subroutine (KEYON) outputs switch signals for the touch electrodes $0, $4, $8, $C when m=$0, $4, $8, $C, and m≠$ 0, $4, $
8. At the time of $C, the touch electrode indicated by data m is used as the reference touch electrode, a predetermined calculation is performed between the touch electrode m-1 adjacent to the left side of this reference touch electrode, and the calculation result is Touch electrode m or m-1 is selected accordingly, and a switch signal of the selected touch electrode is output. Also, m=$0,
When $1, $2, $3, touch electrode $0,
Output switch signals of $4, $8, $C, and when m≠$0, $1, $2, $3, use the touch electrode indicated by data m as the reference touch electrode,
A predetermined calculation is performed between the reference touch electrode and the adjacent touch electrode m-4, and touch electrode m or m-4 is selected according to the calculation result, and the switch signal of the selected touch electrode is activated. Output. When the subroutine (KEYON) ends, the process returns to step S8 of the subroutine and executes the subroutine (TOUTH). continue,
Proceeding to the next step S9, a judgment is made as to whether the data M is greater than "0", and here,
If it is judged as ``YES'', it means that the touch electrode is being touched by the human body, so the process returns to step S8 and steps S8 and S9 are repeated. Since the fingertip has been released, the process moves to the next step S10. Step S10 is to execute a subroutine (DELTA), and step SE of this subroutine is to calculate sensitivity data D for the next touch. , and the resulting data is used as sensitivity data. When this subroutine ends, the process returns to step S2 of the main routine, and similar processing is executed in preparation for the next touch.

In addition, in the above embodiment, the case where the touch is performed with the fingertip of the right hand is shown, but when the touch is performed with the fingertip of the left hand, the touch electrode numbers are assigned sequentially starting from the upper right: $0, $1, $2...$ 7, and the circuit configuration is such that the signals a, input to the sense circuit,
Just invert b.

Furthermore, although the above embodiments have been described as being applied to a calculator watch, it is of course applicable to small electronic calculators and the like.

As described above in detail, the present invention includes a plurality of touch electrodes T ₁ to _{T 16} and a rectangular wave pulse supply means G ₁ to _{G 16} that supplies a rectangular wave pulse signal of a predetermined period to each of the plurality of touch electrodes. ,4-1,4-
2, 4-6, and delayed signal output means 4-3, 4- connected to the plurality of touch electrodes and outputting a delayed signal of the rectangular wave pulse signal whose delay amount differs depending on the touched area when in the touch state. 4,4-
5, and counting means 5-11, 5-7, 5-9 for obtaining the delay amount of the delay signal from the delay signal output means for each of the plurality of touch electrodes as count value data by counting high frequency clock signals. , a count value data storage means (11, FIG. 12) for storing the count value data for each of the plurality of touch electrodes obtained by the counting means, and a count value data storage means (11, FIG. 12) for storing the count value data for each of the plurality of touch electrodes obtained by the counting means; Among the count value data for each electrode, the count value data of the touch electrode adjacent to the touch electrode with the largest count value data is multiplied by a predetermined number (J, K) and compared with the maximum count value data, and the larger one is calculated. Since it is equipped with a touch electrode selection means (9, 10, steps SD1 to SD9 in FIG. 4) that obtains a touch electrode switch signal, even when a plurality of adjacent touch electrodes are touched at the same time, the desired touch electrode can be selected. It is possible to switch only the switches. Therefore, it is particularly effective in devices where the pitch of the touch electrodes is narrow, such as calculator watches and small electronic calculators.

[Brief explanation of drawings]

Figures 1 to 4 a and b are explanatory diagrams of conventional examples; Figure 1 is an external view of the calculator watch;
The figure is a schematic cross-sectional view of Figure 1, Figure 3 is a diagram showing the state in which the touch electrode is touched with a fingertip while visually checking the display on the liquid crystal display panel, and Figure 4a is a diagram showing the state in which the numeric keypad □5 is touched with a fingertip. FIG. 4b shows the part where the touch electrode contacts the fingertip in the case of FIG. 4a, and FIGS. 5 to 14 show an embodiment of the present invention. Figure 5 is a diagram showing the overall system configuration, Figure 6 is a diagram showing touch electrode numbers, Figure 7 is a diagram showing the basic configuration of the sense circuit shown in Figure 5,
8 is an output waveform diagram of various signals showing the operation of FIG. 5, FIG. 9 is a diagram showing a specific configuration of the sense circuit shown in FIG. 5, and FIG. 10 is a diagram of the configuration of the control circuit shown in FIG. 5. 11 is an output waveform diagram of various signals showing the operation of the control circuit shown in FIG. 10, and FIG.
Figure 13 is a diagram showing the contents of the RAM shown in the figure. Figure 13 is a diagram showing the value of the contact capacitance component detected corresponding to each touch electrode when a predetermined touch electrode is touched. 3 is a flowchart showing the operation of the data processing device shown in the figure. T ₁ to T ₁₆ ...Touch electrode, 3...Touch sensor section,
4...Sense circuit, 5...Control circuit, 7...Data processing device.

Claims (1)

[Scope of Claims] 1: a plurality of touch electrodes; a rectangular wave pulse supply means for supplying a rectangular wave pulse signal of a predetermined period to each of the plurality of touch electrodes; a delay signal output means for outputting a delay signal of the rectangular wave pulse signal whose amount differs depending on the touch area; and a high frequency clock signal that outputs a delay amount of the delay signal from the delay signal output means for each of the plurality of touch electrodes. a counting means that obtains count value data by counting; a count data storage means that stores count value data for each of the plurality of touch electrodes obtained by this counting means; Among the count value data for each of the plurality of touch electrodes, the count value data of the touch electrode adjacent to the touch electrode with the largest count value data is multiplied by a predetermined number and compared with the above-mentioned maximum count value data, and the larger one is calculated. 1. A touch switch device comprising touch electrode selection means for obtaining a touch electrode switch signal.