JPH0225529B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinate detection device that detects the position of a pressed point on a pressed object and outputs coordinate data on the X-axis and Y-axis indicating the pressed point position, and in particular, The present invention relates to a coordinate detection device using two resistive films facing each other with dot-like spacers arranged vertically and horizontally at predetermined intervals.

Conventionally, as disclosed in, for example, Japanese Patent Application Laid-Open No. 11580/1983, one of two resistive films placed facing each other with a frame-shaped spacer in between is pressed to bring the two resistive films into contact with each other. 2. Description of the Related Art A coordinate detection device is known that obtains the coordinates of a pressing point of a pressing body such as a writing instrument by detecting the electric potential at the contact point, and thereby inputs handwritten characters, figures, etc. into a computer.

However, in the coordinate detection device described above, insulation between the two resistive films is achieved by a frame-shaped spacer, so if the area of the resistive film is made large, the resistive film will bend due to its own weight, which is an inconvenience. be.

Therefore, as shown in FIG. 1a, two resistive films 1 and 2 are arranged facing each other with dot-shaped spacers 3 arranged vertically and horizontally at predetermined intervals as objects to be pressed.
There is a structure in which by pressing one of the resistive films, both resistive films are brought into point contact in the area where the spacer 3 is absent, as shown in the sectional view of FIG. 1b.
Then, in detecting the pressing point position of the pressing body and outputting the coordinate data, the above-mentioned Japanese Patent Application Laid-Open No.
Similar to the principle of the detection operation disclosed in Publication No. 11580, an operation of applying a predetermined voltage in the X-axis direction of the first resistive film 1 using electrodes 1A and 1B;
Electrodes 2A and 2B are arranged in the Y-axis direction of the second resistive film 2.
The operation of applying a predetermined voltage using It is configured to output as axis and Y-axis coordinate data. Therefore, in a coordinate detection device using such a pressed body, the area of the pressed body can be increased, and it is particularly suitable for inputting handwritten drawings into a computer.

In this case, since the spacer is point-shaped, even if the pressing point is moved continuously, the coordinate data of the pressing point becomes time series data of time intervals related to the moving speed of the pressing point. Therefore, when displaying the trajectory of a pressed point using such a time-series coordinate data string, the computer interpolates the coordinates of the gap corresponding to one dot-like spacer based on the adjacent coordinate data. It is necessary to display the locus of the pressed point as a continuous locus using this calculated value and a time-series coordinate data string.

Incidentally, in such a coordinate detection device, the pressing operation itself is often performed discontinuously in time, for example, when drawing two mutually independent lines.

However, in the past, the coordinate data retrieved by moving the pressing point was simply output in chronological order, so even if pressing operations corresponding to two mutually independent lines were performed, the coordinate data It is not possible to determine whether the time interval between the coordinate data in the row is the time interval when moving the point-shaped spacer portion, or whether it is due to temporal discontinuity of the pressing operation itself. This has the disadvantage that it is displayed as one continuous line, making it impossible to display a locus that faithfully follows the pressing operation.

On the other hand, since the spacer is in the form of a point, the point contact area at the pressing point changes due to fluctuations in the pressing strength, as shown in Figure 1c.
Or, as shown in the cross-sectional view of d, the potential of the contact point taken out from one of the resistive films changes in various ways as shown in the cross-sectional view of d. Even if the contact point is moved to , the potential of the contact point will fluctuate depending on the size of the point contact area, and the coordinate data of the X and Y axes will become discontinuous.
It has the disadvantage that it is recognized or displayed as coordinate data of a curve as shown in .

The present invention has been made to solve these drawbacks, and its purpose is to identify coordinate data in temporally discontinuous pressing operations, and to identify discontinuous phenomena in coordinate data caused by fluctuations in pressing strength. It is an object of the present invention to provide a coordinate detection device capable of outputting coordinate data of a locus that faithfully follows the movement of a pressing point.

For this purpose, the present invention calculates the deviation between coordinate data sequentially taken out as the pressing point moves,
Only the coordinate data whose deviation is less than a predetermined value is treated as continuous coordinate data and ignored as other abnormal data, and a potential signal is generated at the contact point of both resistive films due to the pressure of the resistive film. A timer means for monitoring the time interval is provided, and coordinate data retrieved when the time interval of the potential signal generation is less than a predetermined value is output as coordinate data obtained by discontinuous movement of the pressing point, and is retrieved when the time interval of the potential signal is equal to or greater than the predetermined value. The coordinate data is output as coordinate data obtained by discontinuous movement of the pressing point.

In this specification, coordinate data that is determined to be normal and follows the movement of the pressing point among the sequentially extracted coordinate data strings is defined as the true value of the coordinate data and used for explanation.

Hereinafter, the present invention will be described in detail based on illustrated embodiments.

FIG. 2 is a block diagram showing one embodiment of the present invention. In the figure, an electrode 1A of the first resistive film 1
is connected to a positive drive voltage +V ₁ via a transistor Q ₁ , and one electrode 1B is connected to ground potential via a transistor Q ₂ . Also, the second
The electrode 2A of the resistive film 2 is connected to the positive drive voltage +V ₁ via the transistor Q ₃ , and one electrode 2
B is connected to ground potential via transistor _Q4 .

These transistors Q ₁ to _{Q 4} are configured so that conduction and non-conduction are controlled by signals YD and XD for alternate application of drive voltages output from the output terminal Q of the flip-flop FF ₁ , respectively.

The flip-flop _FF1 is used to alternately switch the application of driving voltage to the two resistive films 1 and 2, and is constituted by a D-type flip-flop. The channel switching signal CHS is input from the processor unit PU to the data input terminal D, and the inverter is input to the clock input terminal CK.
A signal CS obtained by inverting the chip select signal is input by _INV1 .

Therefore, when the flip-flop _FF1 is input with the channel switching signal CHS of logic "1",
When a logic "0" chip select signal is generated from the processor unit PU, a logic "1" signal YD and a logic "0" signal XD are generated after the falling timing of this chip select signal.
Output. That is, when the flip-flop FF ₁ receives the channel switching signal CHS of logic "1" and generates the chip select signal of logic "0", it turns on the transistors Q ₃ and Q ₄ and drives the second resistive film 2. A voltage V ₁ is applied to output a signal that generates a potential gradient in the y-axis direction indicated by the arrow.

On the other hand, when the flip-flop FF ₁ receives the channel switching signal CHS of logic "0",
When a logic "0" channel select signal is generated from the processor unit PU, a logic "0" signal YD and a logic "1" signal XD are output after the fall timing of this chip select signal. That is, flip-flop
FF ₁ receives the channel switching signal CHS of logic "0" and the chip select signal of logic "0".
When CS occurs, transistors Q ₁ and Q ₂ are made conductive, driving voltage V ₁ is applied to the first resistive film 1,
A signal is output that generates a potential gradient in the x-axis direction indicated by the arrow.

Therefore, by alternately switching the channel switching signal CHS sent from the processor unit PU between logic "1" and logic "0", the x-axis direction of the first resistive film 1 and the y-axis direction of the second resistive film A predetermined potential gradient can be generated alternately in the axial direction. As a result, if one resistive film is pressed at an arbitrary coordinate position and both resistive films are brought into point contact, when a potential gradient is generated in the y-axis direction, the position of the pressed point in the y-axis direction is changed between the two resistive films. Through the contact point and the electrode 1B of one of the resistive films 1, it can be taken out as a potential signal VY at a level corresponding to the pressed point position in the y-axis direction.On the other hand, when a potential gradient is generated in the x-axis direction, The position of the pressing point in the x-axis direction can be extracted as a potential signal VX at a level corresponding to the pressing point position in the x-axis direction via the contact point between both resistive films and the electrode 2B of one of the resistive films 2.

The potential signals VY and VX at levels corresponding to the coordinate positions of the press point in the y- and x-axis directions taken out in this way are input to integration circuits ITG ₁ and ITG ₂ via switches SW ₁ and SW _2, respectively. .

Here, the two resistive films 1 and 2 have a driving voltage V ₁
are applied alternately, the integration circuit ITG ₁ ,
The ground potential is directly applied to ITG ₂ , which slows down the integration operation and, in turn, slows down the conversion speed of potential signals VY and VX into digital values. Switches SW ₁ and SW ₂ are provided to prevent this.
In other words, in this type of coordinate detection device, the potential signal
An integrating circuit including a capacitor is added to the input stage of the AD converter to remove ripple and noise components contained in VY and VX and convert the average value of the potential signals VY and VX into digital values. Although it is generally done, in such a configuration, if the ground potential on the drive voltage application side is directly input to the integrating circuit ITG ₁ or ITG ₂ , the capacitor C of these integrating circuits will be discharged by the input of the ground potential. The potential signal extracted from each resistive film
When integrating VY and VX, charging must be restarted from ground potential. Therefore, the integration operation is delayed by the time required to charge from the ground potential to the level of the potential signals VY and VX, and the speed of conversion to coordinate data is slowed down.

For this purpose, switch SW ₁ is a flip-flop
When the output signal YD of FF ₁ is “1” and the inverter
Only when the chip select signal CS output from INV ₁ is "1", it is turned on (closed state) by the output signal of AND gate AG ₁ , and the first resistive film 1
When the driving voltage _V1 is applied to the integrator circuit ITG1, it is in an off state, and the ground potential is controlled so as not to be applied directly to the input of the integrating circuit _ITG1 . Also, switch
SW ₂ is turned on (closed state) by the output signal of AND gate AG ₁ only when the output signal XD of flip-flop FF ₁ is "1" and the chip select signal CS is "1", and the second resistive film is turned on (closed state). 2 to drive voltage
When V ₁ is applied, it is in the off state, and the ground potential is controlled so as not to be applied directly to the input of the integrating circuit ITG ₂ .

This allows the integrator circuit including capacitor C to
ITG ₁ and ITG ₂ integrate the potential signals VY and VX only during the generation period of the chip select signal CS, and apply the integrated value to the new potential signals VY and VX at the timing when the next chip select signal CS is generated. It will now be held until In this case, since the rate of change in the levels of the potential signals VY and VX is relatively small during normal pressing operations, the integration circuits ITG ₁ ,
Capacitor C in ITG ₂ is instantly charged to the level of new potential signals VY and VX,
The integral operation can be completed extremely quickly.

The potential signals VY' and VX' integrated in the integrating circuits ITG ₁ and ITG ₂ in this way are applied to an AD converter having two channels of AD conversion inputs CH1 and CH2.
Input to converter ADC.

AD converter ADC uses channel switching signal CHS
When is “0”, the AD conversion input of the first channel
Select the potential signal VY′ input to CH1,
After the chip select signal becomes a "1" signal, this signal VY' is converted into a corresponding digital value. Then, when the conversion operation is completed after a certain period of time, a conversion completion signal of logic "0" is sent.
The converted value is output as y-axis coordinate data Y with a serial data structure. In addition, the channel switching signal
When CHS is "1", the potential signal VX' input to AD conversion input CH ₂ of the second channel is selected, and after the chip select signal becomes "1" signal, this signal VX' is converted to the corresponding digital value. Convert to Then, the conversion value is converted to the conversion end signal.
Output as x-axis coordinate data X along with EOC.

In this case, the conversion end signal is
Inverted by INV ₂ to processor unit PU
sent to. Then, upon receiving the signal EOC, the processor unit PU reads the x-axis and y-axis coordinate data X, Y in a serial data configuration.

Now, the processor unit PU is an arithmetic processing unit.
Consisting of a CPU, program memory MEM, etc., it performs a series of controls such as reading the coordinate data input from the AD converter ADC and determining its continuity, and outputs it as coordinate data that accurately follows the movement of the pressing point. However, in order to start the program for performing such control, the push detection signal SNS of logic "0" is sent from the output terminal Q of flip-flop FF ₂ .
This is done by inputting .

That is, when the driving voltage V ₁ is applied alternately to the two resistive films 1 and 2, if a pressing operation is started at an arbitrary timing, the potential signals VY, VX corresponding to the pressing point position will be The signal VX is input to the integrating circuit _ITG 2 via switch SW ₂ , while the signal VX is input to the integrating circuit ITG ₂ via switch SW ₂ .
The voltage is divided by and input to the base of transistor _Q5 .

Transistor _Q5 becomes conductive when the pressing operation on the resistive film is started and the level of the potential signal VX exceeds a predetermined value, and a detection signal SNSA of "0" indicating that the pressing operation has started is output from its collector output.
Output. The detection signal SNSA of "0" output from this transistor _Q5 is supplied to the data input terminal D of the D-type flip-flop _FF2 , and is taken in at the rising timing of the chip select signal CS, and the logic "0" signal is output from the output terminal Q. Pressure detection signal
Output as SNS. Therefore, if the chip select signal is generated in a relatively short cycle, the pressure detection signal SNS can be obtained immediately after the pressure operation on the resistive film, and the process of reading the coordinate data X, Y and its continuity can be easily obtained. It is possible to start a program that performs processing such as discrimination. By the way, when detecting that the resistive film is pressed, if a relatively large current is applied to the resistive film 1 by applying the driving voltage _V1 , the potential gradient in the resistive film 1 becomes steep, and the pressure point Depending on the position of the current signal VX, the level of the current signal VX changes significantly. As a result, depending on how the identification level of transistor _Q5 is determined, it may become impossible to identify that a pressing operation has been performed. Therefore, before detecting the pressing operation, the resistive film 1
A small current is applied to the pin to create a gentle potential gradient so that a high-level potential signal VX can be obtained no matter where the pressure is applied. That is, the transistor Q ₂ is made non-conductive by the output signal (“0” signal) of the transistor Q ₆ , and only the positive potential of the driving voltage V ₁ is applied to the resistive film 1 by the transistor Q ₁ , and this resistor is turned off. The overall potential of the membrane 1 is shifted to the positive potential side. By this, the transistor is connected to the resistive film 1.
It is configured to flow a minute current determined by the impedance on the input side of Q ₅ and the integrating circuit ITG ₂ and the resistance value of the resistive film 1. In this case, the signal that makes transistor _Q6 conductive is the AD converter ADC.
The conversion end signal is used. As can be understood, after the conversion operation is completed, the AD converter ADC is in a state of waiting for the input of a new potential signal VY or VX, so this conversion end signal is inverted by the inverter INV ₂ . If the transistor Q ₆ is controlled by the resistor Q 6 , the resistive film 1 is always shifted to the positive potential side after the conversion operation is completed. Therefore, if a pressing operation is performed in this state, a high-level potential signal VX will be obtained no matter where the pressure is applied, and even if the discrimination level of transistor Q ₅ is set slightly high, transistor Q ₅ will be reliably activated. conducts. In other words, it is possible to reliably detect that a pressing operation has been performed. As a result, the program in the processor unit can be reliably started following the pressing operation. In this case, since the discrimination level of the transistor _Q5 can be set to a high value, it is possible to prevent an erroneous press detection signal SNS from being generated due to disturbance noise.

Note that since the coordinates of the pressing point are detected as a pair in the x-axis and y-axis directions, the transistor _Q5 for detecting that a pressing operation has been performed is
It is sufficient to provide it only on the axial potential signal VX side.
The same applies to transistor _Q6 .

Here, with reference to the time chart shown in FIG. 3, the operation until the coordinate data X, Y of the x-axis and y-axis is input to the processor unit PU will be summarized.

First, at time t ₁ , when the chip select signal shown in a of the figure becomes "0", the conversion end signal (b of the same figure) becomes "1" at this falling timing.
The signal is restored and the AD converter ADC goes into a standby state. At this time, the channel switching signal CHS is
, the output signal YD of the flip-flop FF ₁ becomes a "0" signal as shown in the figure d, and one output signal XD becomes a "1" signal as shown in the figure e. “It becomes a signal. This results in
A state is reached in which the driving voltage V ₁ is applied to the first resistive film 1. Furthermore, when the signal XD becomes a "1" signal, a "1" signal is output from the AND gate AG ₂ during the generation period of the chip select signal, and the switch SW ₂ is turned on as shown in FIG. . However, since the pressing operation has not yet been performed at this time, the potential signal VX does not appear on the electrode 2B of the second resistive film 2. Then, at time t ₂ ,
When the chip select signal returns to “0”,
Switch SW ₂ is turned off. At the same time, the AD converter ADC starts the conversion operation. However, at this time, the potential signal VX' to be converted is not input, so at time _t3 , a conversion end signal of logic "0" is output, and all "0" is output.
The coordinate data Y of is output. At this time _t3 , the conversion end signal becomes "0", so that the transistor _Q6 becomes conductive, and the transistor _Q2 , which had been conductive due to the signal XD, becomes non-conductive. This results in
The entire potential of the first resistive film 1 is shifted to the positive potential side, and accordingly, the signal VY taken out from the electrode 1B also shifts to the positive potential side during the generation period of the conversion end signal, as shown in FIG. 3f. Shifted.

When the pressing operation is started at time _t34 in this state, a high-level potential signal VX is taken out from the electrode 2B as shown in FIG. 3g, and the resistor _R1
to the base of transistor _Q5 .
As a result, a signal SNSA as shown in FIG. 3h is output from the collector output of transistor _Q5 . After this, at time t ₄ , the chip select signal
When CS changes to a "0" signal, the signal SNSA is taken into the flip-flop FF2 at this falling timing, and outputted from the flip-flop _FF2 as a press detection signal SNS as shown in FIG. 3i. This causes the processor unit PU to start a program for reading the coordinates of the pressed point.

On the other hand, the pressing operation is started at time _t34 ,
In addition, since the chip select signal is generated between times _t4 and _t5 , a potential signal corresponding to the position of the pressing point in the x-axis direction is generated via switch _SW2 .
VX is input to integrating circuit ITG ₂ . This results in
The integrating circuit ITG ₂ integrates the input signal VX from t ₄ to _{t 5} , outputs a potential signal VX' as shown in FIG. 3j, and supplies it to the AD conversion input CD ₂ of the second channel of the AD converter ADC. do. Then, on the condition that the channel switching signal CHS is "1", the AD converter ADC selects the potential signal VX' supplied to the AD conversion input of the second channel, and the chip select signal becomes "1". At time _t5 , when the potential signal VX' returns to the "signal," the conversion operation of the potential signal VX' into a digital value is started. When the conversion operation ends at time _t6 after a certain period of time, the conversion end signal is set to "0" and the processor unit
Notify the PU that the conversion operation has finished.
As a result, the processor unit PU reads the conversion output of the AD converter ADC, that is, the x-axis coordinate data X.

On the other hand, before reading the x-axis coordinate data X, the processor unit PU sets the channel switching signal CHS to "1" at time _t5 .
This is to switch the application of the drive voltage V ₁ from the first resistive film 1 to the second resistive film 2 at the next time t ₇ . Therefore, when the chip select signal changes to a "0" signal at time _t7 , the output signal YD of the flip-flop _FF1 changes to a "1" signal at this falling timing, and one output signal XD changes to a "0" signal. Changes to As a result, the driving voltage V ₁ for the second resistive film 2 is now applied. At the same time, the switch _SW1 is turned on from time _t7 to _t8 when the chip select signal is generated. Therefore, the potential signal VY corresponding to the pressing point in the y-axis direction taken out from the electrode 1B of the first resistive film 1 is input to the integrating circuit ITG ₁ via this switch SW ₁ . Then, the integrating circuit
ITG ₁ integrates this input potential signal VY while the chip select signal is generated, and outputs the integrated signal.
The AD converter maintains VY′ even after the signal generation has stopped.
It is supplied to the AD conversion input CH1 of the first channel of the ADC. As a result, the signal at time t ₈ to _{t 9}
VY' is converted into a digital value. Then, upon generation of the conversion end signal, the data is read into the processor unit PU.

The above operations are repeated while the pressing operation continues. Thereby, the coordinate data of the pressed point can be obtained as a pair of x-axis and y-axis.

Next, Figure 4 shows the operation of the processor unit PU, which reads the coordinate data ZD output from the AD converter ADC, determines its continuity, and outputs it as coordinate data that faithfully follows the movement of the pressing point. This will be explained with reference to the flowchart shown in .

Note that the flowchart shown in FIG. 4 is constructed on the premise that the trajectory of the pressing point will be displayed on the screen of the display device based on the finally obtained coordinate data, so the trajectory of the pressing point will be displayed. The operation up to this point will be explained.

In FIG. 4, first, in step 100, it is determined whether or not the setting of conditions such as the display color of the locus of the pressed point and its background color has been completed. If the various conditions for this display have been set, the process moves to trajectory display processing.

In the trajectory display process, first step 101
The flag FLG is set to "OH" at the time. The flag FLG is used to determine whether the coordinate data ZD read from the AD converter ADC is the first one at the stage of entering the trajectory display process, and is set to “OH” at the stage of entering the trajectory display process. , indicating that this is the first coordinate data.
When the setting of the flag FLG is completed, the process proceeds to the "CALL SENSE" routine shown in step 102.

The "CALL SENSE" routine uses the pressure detection signal
It is determined whether the signal SNS is "0" or not. First, as shown in the next step 1020, it is determined whether the signal SNS is "0" or not. if,
Pressure detection signal is generated by pressing operation on the resistive film.
If the SNS has become a "0" signal, proceed to the next step 103, the "CALL DATA READ" routine, read the x-axis and y-axis coordinate data X, Y from the AD converter ADC, and send it to the arithmetic processing unit CPU. It is stored in the built-in first register. After this, in steps 1030 and 1031, the currently read x-axis and y-axis coordinate data X and Y are also stored in the second register as coordinate data X' and
Store it as Y′. This means that the trajectory of the press point is set at the previously read coordinate data X, Y as the base point, the newly read current coordinate data X, Y is set as the target point, and these base points and the target point are connected with a straight line. This is because it is displayed by That is, since there is no data that should serve as the base point for displaying the locus for the first read coordinate data X, Y, this first coordinate data is set with the base point of the locus as the target point.

When the reading of the first coordinate data X, Y is completed in this way, the next step 104 is "CALL
The program moves to the "SENSE" routine, and in step 1040, it is determined again whether the press detection signal SNS has become "0". Here, if the press detection signal SNS is "0", the process moves to the "CALL DATA READ" routine of step 105 in order to read the coordinate data X, Y of the next press point. Then, in step 1050, new x-axis coordinate data X is read, and then in step 1051, y-axis coordinate data Y is read, and these coordinate data X and Y are stored in the first register.

Next, when the reading of the second coordinate data is completed, the process advances to step 106, where it is determined whether the flag FLG is "0H".
In other words, "CALL DATA" in step 103
A flag indicating whether the coordinate data X, Y read in the “READ” routine was the first one.
Distinguished by FLG. If the flag FLG is "0H", the process advances to step 107, and in this step, the coordinate data X' read first and stored in the second register, and the coordinate data X' read second and stored in the first register Find the deviation from the coordinate data Similarly, the deviation between the first coordinate data Y' and the second coordinate data Y is determined, and it is determined whether the deviation is a value of "5H" or more. As a result of this determination, if the deviation is "5H" or more, the process returns from step 107 to step 102 and the "CALL SENSE" routine is processed again. In addition,
In this case, the coordinate data X', Y' stored in the second register is invalidated, and the coordinate data X, Y stored in the first register is read second and is the same as the coordinate data X, Y stored in the first register. will be processed as . In other words, the previously read coordinate data X′,
If the deviation between Y' and the newly read coordinate data X, Y on the same coordinate axis is more than "5H", the previously read coordinate data X', Y' is due to fluctuations in pressing strength, etc. In step 1030, the latest coordinate data X, Y stored in the first register is stored in the second register as previously read coordinate data X', Y'. Ru.

However, as a result of the determination in step 107,
The deviation between the first read coordinate data X', Y' and the second read coordinate data X, Y is "5H"
If the coordinate data is less than
X' and Y' are transformed to correspond to pixel coordinates on the screen of the display device. After this, in step 109, the flag FLG is set to "80H",
Furthermore, in step 111, the coordinate data
(stored in the first register) is converted to correspond to pixel coordinates on the screen of the display device.
Then, in the next step 112, data CX', CY' and CX, CY converted into pixel coordinates are transferred to output registers RG3 and RG4. After this, the process proceeds to step 113, where the "CALL LINE" routine is executed and the data is
The pixels at the coordinate positions indicated by CX', CY' and the data CX, CY are connected by a straight line and displayed on the screen.

In this way, when the pixels corresponding to the two pressed points are connected by a straight line and displayed as the locus of the pressed points, next in step 114 the register RG
4 storage data CX, CY are transferred to register RG3. This is to set the pixel coordinates corresponding to the second pressed point as a new base point for trajectory display when the pixel coordinates corresponding to the third pressed point are specified.

When the processing in step 114 is completed, the flag FLG is set to "80H" in the next step 115, and then the process returns to step 1030, where the second coordinate data X stored in the first register is stored in the second register. is stored as data X'. Then, in the next step, the second coordinate data Y stored in the first register is stored in the second register as data Y'.

This moves the state to read the third coordinate data, and presses the "CALL SENSE" button in step 104.
The routine is executed again. If the press detection signal SNS is "0", the "CALL DATA READ" routine in step 105 is executed and the third new coordinate data X, Y is read in steps 1050 and 1051.

This third new coordinate data is stored in the first register.

Next, in step 106, it is determined whether the flag FLG is "0H". At this time, since the flag FLG is set to "80H" in step 115, the process advances to the next step 110.
This time, it is determined whether the deviation between the second coordinate data X', Y' and the third coordinate data X, Y is greater than or equal to "5H". If the deviation is less than "5H", these coordinate data are considered to be continuous. Then, in step 111, the newly read third coordinate data X, Y is converted to correspond to the pixel coordinates on the screen of the display device, and then the second press The pixel coordinates corresponding to the point and the pixel coordinates corresponding to the third pressed point are connected by a straight line and displayed.

The coordinate data sequentially read in this way is displayed as a locus that follows the movement of the pressed point after the continuity of the previous and subsequent coordinate data has been determined. That is, coordinate data with a deviation of less than "5H" are regarded as mutually continuous and correct (true values of coordinate data) and output to the display device.

However, as a result of the determination in step 110,
The deviation between the second coordinate data X', Y' and the third coordinate data X, Y on the same coordinate axis is "5H"
If above, step 110 to step 116
The process proceeds to step 11, where it is determined whether the flag FLG is greater than "81H". At this time, the flag
Since FLG is "80H", the process advances to step 117, where the contents of this flag FLG are incremented. That is, the flag FLG is updated to "81H" in step 117. After this, step 1 is executed without passing through step 1030.
The process returns to 04 and the "CALL/SENSE" routine is executed again. Then, in step 105, the fourth coordinate data X, Y is read. Then step 1 via step 106
Proceed to step 10, where it is determined whether the deviation between the coordinate data X', Y' stored in the second register and the coordinate data X, Y stored in the first register is "5H" or more. be done. In other words, since the process returns directly from step 117 to the "CALL SENSE" routine, the contents of the second register are not updated and the second coordinate data is stored as the true value of the previously read coordinate data. ing. Therefore, in step 110, the deviation between the second read coordinate data X', Y' and the fourth newly read coordinate data X, Y is "5H".
It will be determined whether or not this is the case.

As a result of this determination, if the deviation between the two is less than "5H", the process advances from step 110 to step 111, where the fourth coordinate data X, Y is converted into pixel coordinates, and the same process as in the previous case is performed. Displayed as a trajectory. Therefore, in this case, the third coordinate data is invalid.

However, as a result of the determination in step 110, if the deviation between the second and fourth coordinate data is again "5H" or more, the process proceeds to step 116 again.
Here, it is determined whether the flag FLG is greater than "81H". At this time, since the flag FLG is "81H", the process advances to step 117, where it is incremented to "FLG="82H". After this, as in the previous case, step 10
After the processing of step 4,105 is performed, step 10
At 50 and 1051, the fifth coordinate data X, Y is read and stored in the first register.

Then, step 11 is performed via step 106.
0, and again the coordinate data X, Y stored in the first register (i.e., the fifth coordinate data) and the coordinate data X', Y' stored in the second register (i.e., the fifth coordinate data) second coordinate data)
It is determined whether the deviation from the current value is "5H" or more.

As a result of this determination, if the deviation between the two is "5H" or more, the process advances to step 116 and the flag FLG is reset again.
A determination is made. At this time, since the flag FLG is already set to "82H", the process advances to step 118 and is set to "80H" this time. After this, the process returns to steps 1030 and 1031, and the fifth coordinate data X, Y are stored in the second register as new true values, and the processing of each step subsequent to step 104 is executed thereafter.

That is, in steps 105 to 1051, the sixth coordinate data X, Y is newly read, and then in step 110, the deviation of the fifth coordinate data X', Y' from the sixth coordinate data X, Y is calculated. It is determined whether or not it is “5H” or more. As a result of this determination, if the deviation is less than "5H", step 111 is performed.
The sixth read coordinate data X, Y is converted into pixel coordinates, and the locus is displayed in the same manner as in the previous case. In this case, the third
Since the pixel coordinates corresponding to the second pressing point are stored in register RG3, the pixel coordinates corresponding to the second pressing point and the pixel coordinates corresponding to the sixth pressing point are in a straight line. They will be tied together.
That is, if coordinate data with a deviation of "5H" or more from the previous coordinate data as the true value occurs three times in a row, the next coordinate data is determined as the true value and output for displaying the locus.

In this way, even if the continuity with the previous coordinate data is denied in step 110, if this continues n times, the (n+1)th coordinate data is output as correct, so that the pressed point coordinates can be changed. It is possible to prevent the coordinate data from being dropped when the range of change is large, and it is possible to display a locus that faithfully follows the movement of the pressing point.

Now, the pressing operation is not necessarily performed continuously in time, but may be performed at certain time intervals. In such cases, it is necessary to identify whether the first pressing operation is continuous or not.
The trajectory of the pressing point resulting from two independent pressing operations becomes continuous.

Therefore, this flowchart is provided with a software timer means for identifying the time interval between pressing operations.

That is, in step 1020, it is determined whether the press detection signal SNS is "0" or not.
If SNS is not "0", it is assumed that no pressing operation has been performed, and the process proceeds to step 1021, where the value TMD of the soft timer is set to "FF" (in hexadecimal notation). After this, in step 1022, it is again determined whether the signal SNS is "0" or not.
If not “0”, proceed to the next step 1023,
Here, it is determined whether the value TMD of the soft timer has become "0", that is, whether a predetermined time has elapsed. As a result of this determination, if TMD is not "0", the value of the soft timer is decremented (TMD - 1) in step 1024, and
Return to step 1022. Then, in step 1022, it is again determined whether the signal SNS is "0". And even at this stage, the signal
If SNS is "0", it is assumed that no pressing operation has been performed yet, and steps 1023→1024 are performed.
→The process of 1022 is repeated, and during this repetition, the value TMD of the soft timer is decremented by "1". As a result, the soft timer value TMD is “0”
If this happens, it is assumed that no pressing operation has been performed for a predetermined period of time, and the process returns to step 100, the initial condition determination step.

However, if the pressing operation is performed before the soft timer value TMD reaches "0", the "CALL DATA" from step 1022 to step 103 is
The program moves to the ``READ'' routine and sequentially reads the coordinate data X and Y.

Therefore, when a continuous pressing operation is performed, the coordinate data X and Y are successively read in sequence as described above. However, for two pressing operations separated by a predetermined time interval, the process returns to step 100 after the first pressing operation is completed, and reading of the coordinate data X, Y for the next pressing operation is flagged.
You can start after setting FLG to “0H”.
As a result, coordinate data X and Y for pressing operations that are temporally widely separated are output to the display device while being distinguished from each other, and can be displayed as completely independent trajectories.

This is exactly the same for steps 1040-1044.

As explained above, the present invention calculates the deviation between the coordinate data sequentially taken out as the pressing point moves, and treats only the coordinate data whose deviation is less than a predetermined value as continuous coordinate data, and treats the other coordinate data as continuous coordinate data. A timer means is provided to monitor the generation time interval of a potential signal generated at the contact point of both resistive films due to the pressure of the resistive film, and to ignore it as abnormal. Coordinate data retrieved in the state is output as coordinate data resulting from continuous movement of the pressing point, and coordinate data retrieved in a state exceeding a predetermined value is output as coordinate data resulting from discontinuous movement of the pressing point. .

For this reason, it is possible to identify coordinate data in temporally discontinuous pressing operations, prevent discontinuous phenomena in coordinate data caused by fluctuations in pressing strength, and create coordinate data of a trajectory that faithfully follows the movement of the pressing point. can be output.

[Brief explanation of drawings]

Figure 1a is a diagram showing the structure of the pressed body, Figure 1b
~e are diagrams for explaining the drawbacks of the conventional system, Figure 2 is a block diagram showing an embodiment of the present invention, Figure 3 is a time chart for explaining its operation, and Figure 4 is based on coordinate data. This is a flowchart up to displaying the trajectory. 1, 2...Resistive film, FF ₁ , FF ₂ ...Flip-flop, AG ₁ , AG ₂ ...And gate, SW ₁ ,
SW ₂ ... Switch, Q ₁ ~ _{Q 6} ... Transistor,
ITG ₁ , ITG ₂ ...Integrator circuit, ADC...AD converter, PU...Processor unit, CPU...Arithmetic processing unit, MEM...Memory.

Claims (1)

[Claims] 1. First and second resistive films are arranged opposite to each other with dot-like spacers arranged vertically and horizontally at predetermined intervals, and the X-axis direction of the first resistive film and the Y-axis direction of the second resistive film are By applying a voltage alternately in the directions, the potential signals at the contact point of both resistive films due to the pressure on one resistive film are taken out alternately from the voltage application electrode of the resistive film on the non-voltage side, and these potential signals are exchanged into digital values. In a coordinate detection device that outputs X-axis and Y-axis coordinate data of a pressing point on a resistive film,
a first identification means for identifying discontinuities in the coordinate data string due to temporal discontinuities in the pressing operation of the resistive film by monitoring generation time intervals of the potential signals; A coordinate detection device comprising second identification means for identifying coordinate discontinuities in a data string by comparing deviations between sequentially extracted coordinate data and a predetermined value.