JPH0816305A - Coordinate detector for reflection preventing tablet - Google Patents

Abstract

PURPOSE:To prevent a DC voltage from being continuously impressed to liquid for reflection prevention sealed in a tablet. CONSTITUTION:A counter 2 and an OR gate 73 generate a control signal REV 0 of which the level is inverted in a prescribed cycle during an input waiting period. A changeover switch 66 inverts a voltage level to be impressed to terminals XH and YH of a tablet 51 synchronously with the control signal REV 0. Switches 67 and 68 and an inverter 69 invert a terminal for extracting a control signal MON to be transmitted to a coordinate detecting switch 60 to the side of a terminal YL and a terminal XL synchronously with the control signal REV 0. Thus, by inverting the level of the voltage to be impressed to the tablet 51, the voltage to be loaded to the liquid for reflection prevention sealed in the tablet 51 is made into AC. Therefore, upper and lower conductive films or the liquid for reflection prevention can be prevented from being degraded.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detecting device for an antireflection tablet used for a personal computer, a word processor, an electronic notebook, a portable terminal device or the like having a transparent tablet and capable of pen input.

[0002]

2. Description of the Related Art A transparent touch input device having a transparent tablet as an input device on a display device such as a CRT (cathode ray tube) or a liquid crystal display and used as a pen input device as shown in FIG. (Japanese Patent Laid-Open No. 64-14)
630 publication). In this transparent touch type input device, the resistance film type tablet 2 as an input device is laminated on the display device 1, so that the visibility of the display device 1 is impaired by the reflection of light by the tablet 2. Therefore, in order to suppress the reflection of the light to a minimum, the refractive index between the upper and lower transparent resistance sheets 2a and 2b forming the tablet 2 is close to that of the resistance sheets 2a and 2b, and the electrical insulation property is improved. A liquid (silicone oil or the like) 3 having the above is enclosed.

Among the resistance film type tablets as described above, there are an analog type tablet and a matrix type tablet depending on the configuration and purpose of use.
In the above analog type tablet, as shown in the configuration diagram of FIG. 27 (a) and the sectional view of FIG. 27 (b), a transparent film 5 on which a conductive material (ITO) 6 is printed and a conductive film The glass 7 on which the material (ITO) 8 is printed is laminated so that the conductive materials 6 and 8 face each other. Electrodes 9 and 10 are provided along both sides at both ends of the transparent film 5 on the side of the conductive film 6. Similarly, on both sides of the glass 7 on the side of the conductive film 8, the electrodes 1 are provided along the respective sides.
1 and 12 are provided. Further, it has a structure in which spacers 13 of microdots (diameter of several tens of microns) are uniformly arranged between the electrodes 9 and 10 or between the electrodes 11 and 12, and the whole is an analog switch. An antireflection liquid 14 is sealed between the spacers 13.

Further, as shown in the configuration diagram of FIG. 28 (a) and the sectional view of FIG. 28 (b), the matrix type tablet has a conductive material on two transparent films 15 and 15.
The (ITO) 16, 16 is formed into a strip shape by etching or printing. And two transparent films 1
The transparent switches are formed by stacking 5 and 15 with the conductive films 16 and 16 facing each other and orthogonal to each other with a spacer 17 interposed therebetween. An antireflection liquid 18 is sealed between the spacers 17.

The analog type tablet and the matrix type tablet having the above structures are driven as described below. The analog type tablet is applied to a portable information terminal or the like, and the matrix type tablet is applied to a handy terminal or the like.

As shown in FIG. 29, the coordinate detecting device of the analog type tablet has an internal interrupt generating part 21a for controlling the whole coordinate detecting device, a display part for displaying input information and the like. 22, a resistance film type analog type tablet (hereinafter simply referred to as a tablet) 23 as an input device, a tablet drive unit 24, a storage unit 25 for storing input information and the like, and the tablet 2
3 is generally composed of a pen 26 and the like used for inputting data to the computer 3.

The storage unit 25 stores a system initialization program, a system control program, a calibration program and a coordinate detection program,
A correction data storage area, a pressing data storage area, an internal interrupt interval set value storage area, and a work area are provided. still,
In the work area 25a, an input position storage area for storing the input positions of the four representative points used when executing the calibration program, and an input designated point counter storage area for sequentially instructing the input positions of the four representative points. Further, there is provided a detected coordinate storage area for temporarily storing the coordinates detected by executing the coordinate detection program.

Here, the above-mentioned calibration means that the tablet 23 and the display section 22 laminated below the tablet 23 are displaced from each other, and the actual input point at the time of inputting with the pen 26 is displayed on the display section 22. This is a position correction method used to absorb parallax with respect to the displayed display point, fluctuations and variations in inter-terminal resistance value of the tablet 23 itself, and the like. This calibration is
It is executed when the coordinate detection device is used for the first time or when the above-mentioned shift is felt during use.

In the calibration, the four representative points are input in the inputtable range of the tablet 23, and the position of the input point detected by the tablet drive unit 24 and the display point displayed by the display unit 22 are displayed. The correction data is calculated from the difference from the position. Then, in the subsequent pen input, the above-mentioned shift is absorbed by adjusting the correction data at the pen input position.

As shown in FIG. 30, the tablet driving section 24 includes electrodes 27, 28, 29, 3 of the tablet 23.
ON / OFF connection of terminals XH, XL, YH, YL of 0 and constant potential
Switches 31a to 31d, 32a, 32b to turn off, resistor 3
3a, 33b, an A / D converter 34 for converting output data from the tablet 23 into digital data, and a coordinate detection switch 3 for requesting execution of the coordinate detection program.
5, a pull-down resistor 36 for fixing the coordinate detection switch 35 in the OFF state during the input waiting period, and a drive control unit 24a for controlling the operation of the tablet drive unit 24. The switch 37 is a power-on switch of the control unit 21.

Here, the switches 31a to 31d, 32
The operation of the a, 32b and the A / D converter 34 is performed by the drive control unit 2
Controlled by 4a. On the other hand, the coordinate detection switch 35
From the drive control unit 24a. still,
The electrodes 27 and 28 are provided on either the transparent film side or the glass side of the tablet 23.
Although 9 and 30 are provided on the other side, they are shown in a simplified manner in FIG. Further, the switches 31a to 31d, 32a, 32b and the coordinate detection switch 3
Reference numeral 5 is composed of a transistor or the like.

The above-mentioned analog type tablet is driven as follows. During the input waiting period when the coordinate detection switch 35 is in the off state, the switch 31a is turned on and the electrode 27 is connected to the power supply Vcc via the terminal XH under the control of the drive control section 24a. Then, when an arbitrary position on the tablet 23 is pressed by the pen 26, a voltage is generated in the electrode 30 and a voltage signal is output from the terminal YL, as described in detail later, and the coordinate detection switch 35.
Turns on and switches to the ground side. As a result, the control unit 21 knows that there is a pen input by the INT signal.

Then, the drive control section 24a controls ON / OFF of the switches 31a to 31d, 32a, 32b to apply a voltage alternately between the electrodes 27, 28 and between the electrodes 29, 30 in a time division manner. To do. Hereinafter, applying a voltage between the electrodes 27 and 28 is referred to as "applying a voltage in the X-axis direction", and applying a voltage between the electrodes 29 and 30 is referred to as "applying a voltage in the Y-axis direction". To tell. Then, when a voltage is applied in the X-axis direction, the pen 26 moves from the electrode 30 to the terminal YL.
While the voltage (analog value) corresponding to the tip position of the electrode is output, when the voltage is applied in the Y-axis direction,
A voltage (analog value) corresponding to the position of the tip of the pen 26 is output from the terminal XL. Then, the digital data obtained by converting the voltage value into a digital value by the A / D converter 34 is sent to the drive control unit 24a.

Now, the point K on the tablet 23
Consider the case where is pressed. In this case, the point K on the glass and the transparent film forming the tablet 23
The conductive films at the positions are in contact with each other. Then, when a voltage is applied in the X-axis direction, a circuit as shown in FIG. 31A is formed, and the voltage V ₁ is output from the terminal YL. on the other hand,
When a voltage is applied in the Y-axis direction, a circuit as shown in FIG. 31B is formed, and the voltage V ₂ is output from the terminal XL. The drive control unit 24a detects the pen input position based on the value obtained by A / D converting the voltages V ₁ and V ₂ by the A / D converter 34. At that time, since the input impedance of the A / D converter 34 is very high, the resistance value in the direction connecting the electrodes to which the voltage is not applied (the resistance value r _y in FIG. _31A , the resistance value r _y in FIG. The resistance value r _x ) in) is virtually negligible.

Here, the digital value obtained by the A / D converter 34 at the time of detecting the pen input position described above actually increases the contact resistance value between the electrodes when the input to the tablet 23 is unstable. The value may be different from the pen input position of. Therefore, prior to the above coordinate detection, dummy conversion is performed by the A / D converter 34, it is determined whether the obtained digital value is at a predetermined level or more, and it is checked in advance whether a correct digital value is obtained. To do. Since this dummy conversion is not directly related to this embodiment, detailed description will be omitted.

Hereinafter, pen input performed by the drive control section 24a under the control of the control section 21 based on the system initialization program, system control program, calibration program and coordinate detection program stored in the storage section 25. The position detection processing operation will be described in detail. 32 and 33 are flowcharts of the pen input position detection processing operation.

When the coordinate detection system of the analog tablet is turned on, the drive control section 24a starts its operation, and the pen input position detection processing operation starts based on the system control program. In step S1, this coordinate detection system is initialized. In step S2, the control signal of level "H" is output from the PON terminal of the control unit 21, the switch 37 is turned on, the power supply voltage Vcc is supplied, and the power is turned on. In step S3, the presence or absence of the correction data is confirmed by referring to the correction data storage area in the storage unit 25. As a result, if the correction data is present, the process proceeds to step S4, and if not, the process proceeds to step S5.

In step S4, after the control unit initialization subroutine for initializing the drive control unit 24a is executed based on the system initialization program, the above-described input waiting period is entered. In step S5, the calibration subroutine for performing the above-described calibration is executed based on the calibration program.
After this, the input waiting period starts. Step S6
Then, it is determined whether or not the level of the INT signal from the coordinate detection switch 35 has become "L". as a result,
When it becomes "L" and it is detected that there is a pen input, the process proceeds to step S7.

In step S7, the internal interrupt generating section 21a is generated.
Is started. Thus, at the time interval set based on the internal interrupt interval setting value stored in the storage unit 25,
Internal interrupt processing of the pen input position detection processing becomes possible. In step S8, in response to the internal interrupt from the internal interrupt generator 21a, a coordinate detection subroutine for detecting the coordinates of the pen input position is executed based on the coordinate detection program. In step S9, it is determined whether or not the result of the coordinate detection executed in step S8 is good. As a result, if it is good, the process proceeds to step S10, and if it is not due to insufficient pressing of the pen 26, the process proceeds to step S16. In step S10, the correction data stored in the storage section 25 or the correction data calculated in step S5 and stored in the storage section 25 is used to set the coordinates of the pen input position detected in step S8 to the coordinates described above. The correction data is adjusted to correct the above deviation.

In step S11, the instruction content from the user corresponding to the coordinates of the pen input position corrected in step S10 is confirmed. For example, if the input position coordinates correspond to the position of the icon, the processing content assigned to the specified icon is confirmed, and if the input position coordinates correspond to the image input area, the point display at the pen input position is confirmed. Is done. In step S12, it is determined whether or not the confirmation result in step S11 is the stop of the coordinate detection operation of the pen input position. As a result, if stopped, the process proceeds to step S16, and if not, the process proceeds to step S13.
In step S13, an instruction from the user, display of the pen input position on the display unit 22, and the like are executed according to the confirmation result in step S11.

In step S14, the internal interrupt generation unit 21
It is determined whether there is a next internal interrupt from a.
As a result, if there is an internal interrupt, the process proceeds to step S15.
In step S15, it is determined whether or not the level of the INT signal output from the coordinate detection switch 35 is "L". As a result, if it is "L", it is determined that the pen input is being performed, and the process proceeds to step S17. Otherwise, it proceeds to step S16. In step S16, the internal interrupt generation unit 21
The operation of a is stopped and the operation returns to the input waiting period. In step S17, it is determined whether or not the end of the pen input position detection processing operation has been instructed. As a result, if not instructed, the process returns to step S8 to continue the coordinate detection of the pen input position. On the other hand, if instructed, the pen input position detection processing operation ends.

Next, the calibration subroutine executed in step S5 in the flow chart of the pen input position detection processing operation will be described in detail. FIG. 34 is a flowchart of the above calibration subroutine. If it is determined in step S3 in the flowchart of the pen input position detection processing operation that the correction data is not stored in the correction data storage area in the storage unit 25, the calibration subroutine starts.

In step S21, the control part initialization subroutine is executed. In step S22, the storage unit 25
"1" is set in the input designated point counter n set in the input designated point counter storage area in the work area 25a. The input instruction point counter n is a counter for instructing the number of the representative point to be input by the user at the time of calibration. In step S23, a message prompting the pen input to the position of the representative point designated by the contents of the input designated point counter n is displayed on the display unit 22. After this, the input waiting period starts.

In step S24, the coordinate detection switch 3
It is determined whether or not the level of the INT signal output from 5 has become "L". As a result, when it becomes "L" and the pen input is detected, the process proceeds to step S25. Step S25
Then, the coordinate detection subroutine is executed based on the coordinate detection program. In step S26, it is determined whether or not the result of the coordinate detection executed in step S25 is good. If the result is good, step S
If not, the process returns to step S24 to perform coordinate detection again.

In step S27, the coordinates of the pen input position detected in step S25 are stored in the n-th point of the input position storage area in the work area 25a of the storage unit 25. In step S28, the input designated point counter n
Is incremented. In step S29, it is determined whether or not the content of the input designated point counter n is larger than the maximum value "4". As a result, if it is larger than "4", the process proceeds to step S30, and if it is "4" or less, the process returns to step S23 to start the process of the next representative point.

In step S30, the correction data is calculated by a predetermined method based on the coordinates of the pen input positions associated with the four representative points. The method of calculating the correction data is not directly related to the present invention and will not be described. Step S
In step 31, the correction data calculated in step S30 is stored in the correction data storage area of the storage unit 25 to end the calibration subroutine, and step S in the main routine of the pen input position detection processing operation.
Return to 6.

Next, the control unit initialization subroutine executed in step S4 in the flowchart of the pen input position detection processing operation or step S21 in the calibration subroutine will be described in detail. FIG. 35 is a flowchart of the control part initialization subroutine. Step S in the flowchart of the pen input position detection processing operation
If it is determined that the correction data is stored in the correction data storage area of the storage unit 25 in 3, or
When the calibration subroutine is entered, the control unit initialization subroutine starts.

In step S41, in order to realize the input waiting period, the level of the output port XH0 of the drive control section 24a is set to "H" and the other output ports XL0,
The levels of XL1, YH0, YL0, and YL1 are set to "L", and the control unit initialization subroutine ends. After that, the process returns to step S6 in the main routine of the pen input position detection processing operation or step S22 in the calibration subroutine. As a result, the voltage Vcc is applied only to the electrode 27 through the terminal XH, and the pen input from the tablet 23 is awaited. Then, when there is a pen input, the coordinate detection switch 35 is turned on as described above, the level of the INT signal becomes "L", and the pen input is detected by the drive control unit 24a.

Next, the coordinate detection subroutine executed in step S8 in the flow chart of the pen input position detection processing operation or step S25 in the calibration subroutine will be described in detail. 36 and 37 are flowcharts of the coordinate detection subroutine. When the internal interrupt generation section 21a of the control section 21 is activated in step S7 in the flow chart of the pen input position detection processing operation, or in step S24 in the flow chart of the calibration subroutine described above.
When the level of the T signal becomes "L", the coordinate detection subroutine starts.

In step S51, the level of the output port YL1 is set to "H" and the switch 32b is turned on. In step S52, it is determined whether or not the level of the signal ADEND indicating the end of A / D conversion output from the A / D converter 34 is "H". As a result, if it is "H" (that is, A / D conversion ends), step S53.
Proceed to. In step S53, the digital data DATA from the A / D converter 34 is fetched as the X coordinate value of the pen input position and set in the buffer DX. In step S54, it is determined whether or not the content of the buffer DX is smaller than the content of the X coordinate value DCX stored in the pressing data storage area. As a result, if it is smaller, the process proceeds to step S57, and if not, the process proceeds to step S55.

Here, the above steps S51 to S54.
In, the above-mentioned dummy conversion is carried out. Then, the digital value DX obtained by the dummy conversion is X.
If it is smaller than the coordinate value DCX, a correct digital value is obtained, so that step S57 and subsequent steps are executed to perform the original X coordinate detection.

In step S55, the level of the output port YL1 is set to "L" and the switch 32b is turned off.
In step S56, "0" is set to the flag indicating the quality of the coordinate detection result, and the coordinate detection subroutine ends. Then, the process returns to step S9 in the main routine of the pen input position detection processing operation or to step S26 in the calibration subroutine.

In step S57, the level of the output port YL1 is set to "L" and the switch 32b is turned off.
On the other hand, the level of the output port XL0 is set to "H" and the switch 31b is turned on. As a result, the switches 31a and 31b are turned on and a voltage is applied in the X-axis direction, which is equivalent to the circuit shown in FIG. 31 (a). Step S5
At 8, it is judged whether or not the level of the signal ADEND from the A / D converter 34 is "H". As a result, if it is "H", the process proceeds to step S59. In step S59, the digital data DATA from the A / D converter 34 is fetched as a normal X coordinate value of the pen input position and set in the buffer DX.

In step S60, output ports XH0 and XL
When the level of 0 is set to "L", the switches 31a, 3
1b is turned off. On the other hand, the levels of the output ports XL1 and YH0 are set to "H", and the switches 31c and 32a are turned on. In steps S61 to S63, dummy conversion related to Y coordinate detection is performed in the same manner as steps S52 to S54. When the digital value DY obtained by the dummy conversion is smaller than the Y coordinate value DCY stored in the pressing data storage area, the correct digital value is obtained, and therefore, step S66 and the subsequent steps are executed to execute the original Y coordinate. Detection is done.

At step S64, the output ports XL1, YH
The level of 0 is set to "L" and switches 31c and 32a
Is turned off. On the other hand, the level of the output port XHO is set to "H" and the switch 31a is turned on. In step S65, the flag is set to "0" and the coordinate detection subroutine is ended. Then, step S9 in the main routine of the pen input position detection processing operation,
Alternatively, the process returns to step S26 in the calibration subroutine.

In steps S66 to S69, the switches 31c,
31d is turned on, a voltage is applied in the Y-axis direction, the digital data DATA from the A / D converter 34 is taken in as a normal Y coordinate value of the pen input position, and the buffer DY
Is set to In step S70, the coordinates (DX, DY) of the pen input position composed of the X coordinate value "DX" stored in the buffer DX in step S59 and the Y coordinate value "DY" stored in the buffer DY in step S68.
Are stored in the detected coordinate storage area in the work area 25a of the storage unit 25. In step S71, the flag is set to "1" and the coordinate detection subroutine ends. Then, the process returns to step S9 in the main routine of the pen input position detection processing operation or to step S26 in the calibration subroutine.

After that, in step S9 of the main routine of the pen input position detection processing operation or in step S26 of the calibration subroutine, when it is determined whether the coordinate detection result is good or not, the operation is performed based on the content of the flag. To be seen.

FIG. 38 is a timing chart when the above pen input position detection processing operation is executed. The figure shows that the pen 26 is separated from the tablet 23 when the coordinate detection is performed twice. The following can be seen from FIG. That is, in the procedure "waiting for input", the terminals XH and XL of the tablet 23 have the same potential, and the terminals YH and YL have the same potential. Therefore, the application direction of the voltage applied between the terminals XH and YL and the application direction of the voltage applied between the terminals XL and YH are the same. Also, the procedure "X coordinate detection"
, The potential difference between the terminals XH and XL is the same twice, and in the procedure "Y coordinate detection", the potential difference between the terminals YH and YL is the same twice. In addition, coordinate detection is performed each time there is an internal interrupt.

FIG. 39 shows the voltage applied to the tablet 23 during the above procedure "waiting for input". The electrode 27 provided on the upper conductive film 38 is connected to the power supply Vcc, while the electrode 30 provided on the lower conductive film 39.
Is grounded through the resistor 36. Therefore, the unidirectional voltage from the upper conductive film 38 to the lower conductive film 39 is increased.
(DC voltage) is applied, and a DC voltage is applied to the antireflection liquid 40 enclosed between the transparent film of the tablet 23 and the glass.

As shown in FIG. 40, the coordinate detecting device for the matrix type tablet has an internal interrupt generating section 41a.
And a control unit 41 for controlling the entire coordinate detection device.
The display unit 42 for displaying input information and the like, a resistance film type 4 × 4 matrix type tablet (hereinafter simply referred to as a tablet) 43 as an input device, and a storage unit 44 for storing the input information and the like are roughly configured. It

The storage unit 44 stores a system initialization program, a system control program and a tablet control program, and is provided with an internal interrupt interval set value storage area and a work area. In the work area 44a, an input position storage area for storing a number of input positions corresponding to the number of lines of the tablet 43 (“4” in this embodiment) and a line counter for sequentially instructing these four input positions are provided. A storage area is provided.

FIG. 41 shows a tablet drive controller provided in the controller 41. The drive control unit 45 generates a strobe signal for scanning each line of the tablet 43 and holds the detected position data. The output ports S0 to S3 of the drive control unit 45 and the lines of the tablet 43 are provided with a device protection resistor 46 for preventing current from flowing when a plurality of elements in the matrix of the tablet 43 are pressed at the same time. Connected through. Further, it has a pull-down resistor 47 for stabilizing the level of the data signal when not input.

The matrix type tablet is driven in the same manner as in the case of driving the keyboard switch as follows. That is, the voltage of the output ports S0 to S3 is sequentially raised to the level "H" at a constant interval (scanning), and the voltage of the input ports D0 to D3 is read each time, so that the touch position on the tablet 43 is detected. Of.

For example, when the point K on the tablet 43 is touched, the upper strip-shaped conductive film located at the point K (see FIG. 28 (a)) and the lower strip-shaped conductive film. The membranes (see Figure 28 (a)) make contact. Then, as shown in the timing chart of FIG. 42, when the output port S1 is scanned, the level of only the input port D2 becomes "H". Therefore, the input coordinates on the tablet 43 are detected from the position of the input port (D2) whose level has become “H” and the position of the output port (S1) scanned at that time. Here, when the point G is also touched at the same time when the point K is touched, current tends to flow in the order of output port S1 → point K → point G → output port S2. In that case, in order to protect the drive control unit 45, the above-mentioned device protection resistor 46 is arranged for each of the output ports S0 to S3.

Below, under the control of the control unit 41 based on the tablet control program stored in the storage unit 44,
The input position detection processing operation executed by the drive control unit 45 will be described in detail. FIG. 43 is a flowchart of the input position detection processing operation. When the power supply of the control unit 41 is turned on, the input position detection processing operation starts.

In step S81, the internal interrupt generation section 41 is used.
a is activated. In this way, the internal interrupt processing of the input position detection processing becomes possible at the time interval set based on the internal interrupt interval setting value stored in the storage unit 44. In step S82, the levels of all the output ports S0 to S3 in the drive section 45 are set to "L", and "1" is set in the row counter i set in the row counter storage area in the work area 44a of the storage section 44. Set. In step S83, the voltage level of the i-th output port S _i of the output ports S0 to S3 is set to “H”.

In step S84, DATA (i) set in the i-th row of the input position storage area in the work area 44a of the storage section 44 is set to the voltage level (data level) of all the input ports D1 to D3 during i-row scanning. Information indicating the signal level) is stored. In step S85, the level of the i-th output port S _i is set to “L”, and the content of the row counter i is incremented. In step S86,
It is determined whether or not the content of the row counter i is larger than the maximum value "4". As a result, if it is larger than "4", the process proceeds to step S87, and if it is "4" or less, the process returns to step S83 to start the process of the next row.

In step S87, the coordinates of the input position are obtained based on the contents of DATA (i) stored in step S84. Then, the instruction content from the user associated with the input position coordinates is confirmed. Step S88
Then, according to the confirmation result in step S87, the program corresponding to the instruction content is displayed, the input position is displayed on the display unit 42, and the like. Here, if the user does not input to the tablet 43, D for all scan lines
The content of ATA (i) becomes “0”, and the content of instruction becomes “do nothing”.

In step S89, the internal interrupt generation section 41 is used.
It is determined whether there is a next internal interrupt from a.
As a result, if there is an internal interrupt, the process proceeds to step S90.
In step S90, it is determined whether or not the end of the input position detection processing operation has been instructed. As a result, if not instructed, the process returns to step S82 and the coordinate detection of the input position is continued. On the other hand, if instructed, the input position detection processing operation ends.

FIG. 42 is a timing chart when the input position detection processing operation is executed. The figure corresponds to the case where the coordinate detection is performed twice. From FIG. 42, the levels of the strobe signals output from the output ports S0 to S3 corresponding to the scan rows of the drive control unit 45 sequentially become “H”, and at that time, the strobe signals correspond to columns other than the input position (point K). The levels of the input ports D0, D1, D3 are always "L". Therefore, the application direction of the voltage applied between the scanning row and the column where the input position does not exist in the tablet 43 is as follows.
It turns out that it is always the same. Further, it can be seen that the internal interrupt starts scanning from the output port S0 side.

FIG. 44 shows the voltage applied to the tablet 43 when the input position detection processing is executed. The strip-shaped conductive film 49a formed on the upper transparent film 48a constituting the tablet 43 is connected to the drive control unit 45, and the output port S _i connected to the conductive film 49a related to the scanning row. Since the voltage level of the above is "H", it is equivalent to the conductive film 49a on the upper transparent film 48a side being connected to the power supply Vcc. On the other hand, the strip-shaped conductive film 49 b formed on the lower transparent film 48 b is grounded via the pull-down resistor 47. Therefore, a unidirectional voltage (DC voltage) is applied from the upper transparent film 48a to the lower transparent film 48b, and DC is applied to the antireflection liquid 50 enclosed between the two transparent films 48a and 48b of the tablet 43. The voltage is applied.

[0052]

In the coordinate detecting device for the analog type tablet 23, during the input waiting period, the control unit initialization subroutine is executed in step S4 in the flow chart of the pen input position detection processing operation. , Or, as a result of the execution of the calibration subroutine in step S5, the output port XH
The level of 0 is set to "H", and the level of the output port YL0 is set to "L". Therefore, the DC voltage Vcc is always applied from the upper conductive film 38 to the lower conductive film 39. On the other hand, during the coordinate detection period, as a result of execution of the coordinate detection subroutine in step S8, the DC voltage V is constantly applied from the electrodes 27, 29 side to the electrodes 28, 30 side.
cc is required.

In the coordinate detecting device for the matrix type tablet 43, the level of the output port S _i is set to "H" at step S83 in the flow chart of the input position detection processing operation. Therefore, the DC voltage Vcc is constantly applied from the conductive film 49a on the upper transparent film 48a connected to the output port S _i to the conductive film 49b on the lower transparent film 48b.

Therefore, in any of the analog type and matrix type tablets 23, 43, if the enclosed antireflection liquids 40, 50 are not completely insulating materials, the conductive films 38, 39, 49a, 49
b or there is a problem that electrolysis (ionization) due to a redox reaction occurs between the transparent film and the antireflection liquids 40 and 50 to cause deterioration.

However, as the antireflection liquid sealed in the tablets 23 and 43, there are very few perfect insulating materials.

Therefore, an object of the present invention is to provide a coordinate detecting device for an antireflection tablet which does not continuously apply a DC voltage to the antireflection liquid enclosed in the tablet.

[0057]

In order to achieve the above-mentioned object, the invention according to claim 1 is such that two substrates having a transparent conductive film formed on one surface thereof are made to face each other with the conductive film side facing each other. An anti-reflection tablet of the resistance film type is used, in which an anti-reflection material having a refractive index close to that of this substrate is enclosed between the above two substrates, and the input coordinates on this anti-reflection tablet are used. In the coordinate detection device of the antireflection tablet for detecting the coordinate detection unit, the coordinate detection unit is characterized by having an inverting means for inverting the application direction of the voltage applied to the antireflection tablet at predetermined time intervals. .

The invention according to claim 2 is the coordinate detecting device for an antireflection tablet according to the invention according to claim 1, wherein the antireflection tablet has the conductive film uniformly formed on one surface of the substrate. The tablet is an analog type tablet, and the coordinate detection unit has a tablet drive unit that drives the antireflection tablet and a control unit that controls the operation of the tablet drive unit. The first switching circuit for switching the conductive film for applying a predetermined voltage in the antireflection tablet to the upper conductive film and the lower conductive film, and the conductive film grounded in the antireflection tablet are The second switching circuit for switching between the conductive film and the conductive film on the upper side, and the first waiting period during the input waiting period waiting for input to the antireflection tablet. And etching circuit and the second switching circuit is characterized in that a control signal generating circuit for generating a control signal for switching control at intervals of the predetermined time.

The invention according to claim 3 is the coordinate detecting device for an antireflection tablet according to the invention according to claim 1, wherein the antireflection tablet has the conductive film uniformly formed on one surface of the substrate. The coordinate detection unit has a tablet drive unit that drives the anti-reflection tablet and a control unit that controls the operation of the tablet drive unit, and the control unit is configured to perform the predetermined time. And a time measuring means for outputting a signal representing the interval of the predetermined time every time the predetermined time elapses, and a signal from the time measuring means during the input waiting period to receive a predetermined value in the antireflection tablet. It is characterized in that it has a voltage switching means for switching the conductive film for applying the voltage to the upper conductive film and the lower conductive film.

The invention according to claim 4 is the coordinate detecting device for an antireflection tablet according to the invention according to claim 1, wherein the antireflection tablet has the conductive film uniformly formed on one surface of the substrate. The coordinate detection unit has a tablet drive unit that drives the anti-reflection tablet and a control unit that controls the operation of the tablet drive unit. A part of the conductive film on the upper side of the antireflection tablet to which a predetermined voltage is applied and a part to be grounded are a terminal provided at one end in one direction and a terminal provided at the other end in the one direction. The first switching circuit for reversing with and the place where the predetermined voltage is applied and the place where it is grounded in the conductive film under the antireflection tablet are orthogonal to the one direction. A second switching circuit for reversing a terminal provided at one end in the other direction and a terminal provided at the other end in the other direction, and a coordinate detection period for detecting input coordinates on the antireflection tablet, Each time the input coordinate is detected once, the first switching circuit and the second switching circuit
It is characterized in that a control signal generation circuit for generating a control signal for switching control with the switching circuit is provided.

The invention according to claim 5 is the coordinate detecting device for an antireflection tablet according to the invention according to claim 1, wherein the antireflection tablet has the conductive film formed in a stripe shape on one surface of the substrate. The tablet is a matrix type tablet in which the two substrates are laminated so that the respective conductive films are orthogonal to each other, and the coordinate detecting section includes a tablet driving section for driving the antireflection tablet and the tablet driving section. The tablet drive section has a control section for controlling the operation of the section, and inverts the level of the voltage signal applied to the conductive films arranged in the row direction in the antireflection tablet and outputs an inverted signal to the tablet drive section. An inverter circuit for switching, and one of the voltage signal and the inverted signal from the inverter circuit is switched and selected and sent to the antireflection tablet. 1 switching circuit, a second switching circuit for switching the conductive film arranged in the column direction of the antireflection tablet to either a predetermined voltage side or a ground side, and a conductive circuit arranged in the row direction of the antireflection tablet. A control signal generating circuit for generating a control signal for switching between the first switching circuit and the second switching circuit based on the voltage signal applied to the last conductive film to be scanned Is characterized by.

The invention according to claim 6 is the coordinate detecting device for an antireflection tablet according to the invention according to claim 1, wherein the antireflection tablet has the conductive film formed in a stripe shape on one surface of the substrate. The tablet is a matrix type tablet in which the two substrates are laminated so that the respective conductive films are orthogonal to each other, and the coordinate detecting section includes a tablet driving section for driving the antireflection tablet and the tablet driving section. The control unit has a control unit for controlling the operation of, and the control unit measures the predetermined time and outputs a signal indicating an interval of the predetermined time every time the predetermined time elapses, and the time measurement. In response to the signal from the means, the level of the voltage applied to the conductive films arranged in the row direction and the voltage applied to the conductive films arranged in the column direction in the antireflection tablet. It is characterized by having a voltage inverting means for inverting the level alternately.

[0063]

In the invention according to claim 1, a voltage is applied to the antireflection tablet formed by enclosing the antireflection material between the substrates of the resistive film type tablet, and the coordinate detection unit inputs the input coordinates on the antireflection tablet. Is detected. At this time, the direction of application of the voltage applied to the antireflection tablet is reversed by the reversing means of the coordinate detecting section at predetermined time intervals. In this way, the input coordinates are detected so that the DC voltage is not continuously applied to the antireflection material.

Further, in the invention according to claim 2, the control signal generating circuit in the tablet driving section constituting the coordinate detecting section causes the first switching circuit and the second switching circuit to be separated by the predetermined time interval during the input waiting period. A control signal for switching control is generated by. Then, when the first and second switching circuits are switched based on this control signal and a predetermined voltage is applied to the upper conductive film of the antireflection tablet, the lower conductive film is Grounded. On the other hand, when a predetermined voltage is applied to the lower conductive film, the upper conductive film is grounded. In this way, the application direction of the voltage applied to the analog type antireflection tablet during the input waiting period is reversed at the above intervals.

Further, in the invention according to claim 3, a signal indicating the interval of the predetermined time is measured each time the predetermined time is measured by the time measuring means in the control unit constituting the coordinate detection unit and the predetermined time elapses. Is output. Then, by the voltage switching means, every time the signal is received in the input waiting period, the conductive film for applying the predetermined voltage in the antireflection tablet is switched between the upper conductive film and the lower conductive film. . In this way, the application direction of the voltage applied to the analog type antireflection tablet during the input waiting period is reversed at the above intervals.

Further, in the invention according to claim 4, the control signal generating circuit of the tablet driving section controls switching between the first switching circuit and the second switching circuit each time the input coordinates are detected once during the coordinate detection period. A control signal is generated to control. Then, the first and second switching circuits are switched based on the control signal, and a predetermined voltage is applied to one end portion of the upper conductive film of the antireflection tablet in one direction, while the one direction. When the other end is grounded, a predetermined voltage is applied to one end of the lower conductive film in the other direction orthogonal to the one direction, while the other end of the other direction is grounded. It Also,
One end of the upper conductive film in one direction in the other direction is grounded while one end of the lower conductive film in the other direction is applied while the predetermined voltage is applied to the other end. Is grounded, while the predetermined voltage is applied to the other end. In this way, the application direction of the voltage applied to the analog type antireflection tablet during the coordinate detection period is reversed every time the input coordinate is detected.

Further, according to the present invention, if the control section is provided with the correction value generating means and the detected coordinate correcting means, the following can be achieved. That is, when the predetermined voltage is applied to the one end of each of the conductive films by the switching control of the first and second switching circuits by the control signal, the coordinate detecting unit is caused by the correction value generating means. Based on the coordinates of the specific input position on the antireflection tablet detected in step 1, the first correction value for correcting the deviation of the detected coordinates is obtained by a predetermined method. On the other hand, when the predetermined voltage is applied to the other end of each of the conductive films, the correction value generating means causes the second value based on the coordinates of the specific input position detected by the coordinate detecting unit. The correction value is obtained by a predetermined method.

Then, in the subsequent detection of the input coordinates, when the predetermined voltage is applied to the one end of each of the conductive films by the detection coordinate correction means, it is detected by the coordinate detection section. The input coordinates on the antireflection tablet are corrected using the first correction value. On the other hand, when the predetermined voltage is applied to the other end of each conductive film, the input coordinate seat detected by the coordinate detection unit is corrected using the second correction value.
Thus, even if the application direction of the voltage applied to the analog type antireflection tablet during the coordinate detection period is reversed, the correct coordinates of the input position can be obtained.

According to the fifth aspect of the invention, the voltage applied to the last scanned conductive film in the matrix type anti-reflection tablet by the control signal generation circuit in the tablet drive section constituting the coordinate detection section. Based on the signal, a control signal that controls switching between the first switching circuit and the second switching circuit at the predetermined time interval is generated. Then, the first and second switching circuits are switched based on the control signal,
The voltage signals applied to the conductive films arranged in the row direction in the antireflection tablet are inverted by the inverter circuit, and when the inverted signal is sent to the antireflection tablet, the conductivity signals arranged in the column direction are used. A predetermined voltage is applied to the film. On the other hand, when the voltage signal is sent to the antireflection tablet, the conductive films arranged in the column direction are grounded. In this way, the application direction of the voltage applied to the matrix-type antireflection tablet is reversed every scanning.

In the invention according to claim 6, the predetermined time is measured by the time measuring means in the control unit which constitutes the coordinate detection unit, and a signal representing the interval of the predetermined time is output. Then, each time the voltage reversing means receives the signal, the level of the voltage applied to the conductive films arranged in the row direction and the voltage applied to the conductive films arranged in the column direction in the matrix type antireflection tablet are applied. The voltage level is alternately inverted. In this way, the application direction of the voltage applied to the matrix-type antireflection tablet is reversed every scanning.

[0071]

The present invention will be described in detail below with reference to the embodiments shown in the drawings. <First Embodiment> In this embodiment, the purpose of not applying a DC voltage to the antireflection liquid during the input waiting period is to be achieved by hardware. The coordinate detection device for the antireflection tablet in the present embodiment is for detecting the input coordinates in the above-mentioned analog type tablet, and its basic configuration is the same as the configuration shown in FIG. 29. It is called a tablet), a tablet drive unit, a control unit, a display unit and a storage unit. Since the tablet, the control unit, the display unit and the storage unit have the same configurations as the tablet 23, the control unit 21, the display unit 22 and the storage unit 25 shown in FIG. 29, detailed description thereof will be omitted.

FIG. 1 is a block diagram of the tablet driving section in the coordinate detecting device for the antireflection tablet of this embodiment. This tablet drive unit has switches 56a to 56 that operate in the same manner as the tablet drive unit shown in FIG.
d, 57a, 57b, resistors 58a, 58b, A / D converter 5
9, a coordinate detection switch 60, a pull-down resistor 61, a power-on switch 62, and a drive controller 63.

Further, the tablet driving unit in this embodiment is provided with a resistor 64 and a capacitor 6 which form an integrating circuit.
5, a changeover switch 66 for switching the terminal connected to the switch 56a between the terminal XH and the terminal YH, a switch 67 for controlling ON / OFF of the connection between the terminal XL and the coordinate detection switch 60, a terminal YL and the coordinate detection switch 60 A switch 68 for controlling on / off of the connection, an inverter 69 for alternately turning on the switches 67, 68, and switches 67, 6
8 for transmitting the output of 8; an inverter 71 for inverting the level of the INT signal from the coordinate detection switch 60; a counter 72 for giving a timing for inverting the voltage applied to the tablet 51; It has an OR gate 73 for controlling the output.

FIG. 2 is a timing chart when the pen input position detecting process is executed by the coordinate detecting device of the antireflection tablet having the above-mentioned configuration. Hereinafter, FIG. 1 and FIG.
The pen input position detecting operation by the coordinate detecting device of the antireflection tablet will be described below. In the procedure “waiting for input” (see FIG. 2), the drive control unit 63 causes the output port XH as in the tablet drive unit shown in FIG.
Set the voltage level of 0 to "H" to turn on the switch 56a,
The electrode 52 is connected to the power source Vcc. Then, the control signal MO
The coordinate detection switch 60 is controlled to be turned on / off according to the level of N, and an INT signal is sent to the control unit 63.

In the present embodiment, the level of the voltage applied to each electrode of the tablet 51 when the input is waited is reversed so that the antireflection liquid enclosed in the tablet 51 is supplied with a DC voltage in one direction. Do not keep the voltage applied.
The inversion of the level at that time is performed by the changeover switch 66 and the switch 6 by the control signal REV0 or its inverted signal REV1 obtained based on a clock described later.
This is done by controlling the switching of 7,68.

In the state shown in FIG. 1, the voltage signal generated at the electrode 55 when the electrode 52 is connected to the power supply Vcc is used as the control signal MON as in the case of the tablet drive unit shown in FIG. It is designed to be sent to. In this case, a DC voltage Vcc is applied from the upper conductive film forming the tablet 51 to the lower conductive film, as in FIG. 39.

In this state, the control signal REV0
When the level is reversed, the changeover switch 66 is changed over, the switch 68 is turned off, and the switch 67 is turned on.
Contrary to the case of FIG. 1, the voltage signal generated at the electrode 53 when the electrode 54 is connected to the power supply Vcc is sent to the coordinate detection switch 60 as the control signal MON. In this case, a DC voltage Vcc is applied from the lower conductive film to the upper conductive film.

In synchronization with the level inversion of the control signal REV0, the level of the inversion signal REV1 is inverted, and the electrode 5
2, 5 (terminal XH, YL) voltage application direction and electrode 5
It can be understood from FIG. 2 that the voltage application direction between 4, 53 (terminals YH, XL) is reversed.

The clock used as the basis for generating the control signal REV0 is obtained by dividing the clock CLK used in the drive control unit 63 by the counter 72 to several hundreds of hertz. Then, the OR gate 73 takes the logical sum of the output signal of the counter 72 and the inverted signal of the INT signal from the inverter 71 to generate the control signal REV0. Therefore, when the level of the INT signal becomes "L" (that is, when the input waiting period ends), the level of the control signal REV0 is fixed to "H".

The structure of the counter 72 is uniquely determined if the frequency of the input clock and the level inversion frequency of the voltage applied to the tablet 51 are determined. For example, if a clock clock (32 kHz) is used as the input clock and the level inversion frequency is 125 Hz, an 8-bit counter (two 4-bit counters) can be used as the counter 72.

When the switches 56a and 56b are turned on at the same time and the switches 67 and 68 are simultaneously turned on at the same time, a current flows backward to the drive control unit 63 to destroy the drive control unit 63. In order to prevent
The diode 70 is arranged. Further, the coordinate detection switch 60 may be erroneously turned on by an extremely short pulse generated in association with the switching operation based on the control signal REV0. Therefore, the control circuit MON is obtained by blunting the very short pulse generated in the output signal OUT from the diode 70 by using an integrating circuit composed of the resistor 64 and the capacitor 65 as shown in FIG.

FIG. 3 shows the voltage applied to the tablet 51 during the procedure "waiting for input". FIG. 3A shows the case where the level of the control signal REV0 is "H", and the upper conductive film 74 provided with the electrodes 52 and 53 for applying a voltage in the X-axis direction is connected to the power supply Vcc. Meanwhile, the above Y
The lower conductive film 75 provided with the electrodes 54 and 55 for applying a voltage in the axial direction is grounded via the resistor 61.
Therefore, from the upper conductive film 74 to the lower conductive film 7
DC voltage is applied to 5. FIG. 3B shows the control signal RE.
When the level of V0 is "L", the upper conductive film 7
4 is grounded through the resistor 61, while the lower conductive film 75 is connected to the power supply Vcc. Therefore, a DC voltage is applied from the lower conductive film 75 to the upper conductive film 74.

Then, in the present embodiment, as described above, in synchronization with the level inversion of the control signal REV0, as shown in FIG.
The state of (a) and the state of FIG. 3 (b) appear alternately. Therefore, the voltage applied to the antireflection liquid 76 enclosed between the transparent film of the tablet 51 and the glass can be converted into an alternating current,
It is possible to prevent deterioration of the antireflection liquid 76 and the conductive films 74 and 75 due to electrolysis.

As described above, in this embodiment, during the input waiting period, each terminal XH,
The level of the voltage applied to XL, YH, YL is counted by the counter 72.
And a control signal REV0 generated by the OR gate 73
I'm trying to flip it. Therefore, the upper conductive film 7 is synchronized with the level inversion of the control signal REV0.
4 and the lower conductive film 75 can be reversed in direction. That is, the voltage applied to the antireflection liquid 76 enclosed in the tablet 51 can be converted into an alternating voltage to prevent the antireflection liquid 76 and the conductive films 74 and 75 from being deteriorated. As a result, according to the present embodiment, it is possible to use an electrolytic substance such as alcohol or water as the material of the antireflection liquid 76.

At this time, the switches 67 and 68 are turned on / off in synchronization with the level inversion of the control signal REV0, and the control terminal of the coordinate detection switch 60 is connected to the tablet 5.
The terminal YL and the terminal XL are connected alternately. Therefore, the terminals XH, XL, and
Even if the voltages applied to YH and YL are inverted in level, the pen input can be surely detected and the INT signal can be output.

Further, according to this embodiment, the program used when executing the pen input position detection processing operation is as shown in FIG.
The program stored in the storage unit 25 in the conventional analog type tablet coordinate detecting device shown in FIG. 9 can be used as it is. Therefore, the development cost can be reduced.

<Second Embodiment> In this embodiment, the purpose of not applying a DC voltage to the antireflection liquid enclosed in the tablet during the input waiting period is to be achieved by software. The coordinate detecting device for the antireflection tablet in the present embodiment detects the input coordinate in the above-mentioned analog type tablet, and its basic configuration is as shown in FIG.

In FIG. 4, an analog type tablet
A tablet (hereinafter, simply referred to as a tablet) 81, a tablet drive unit 82, a control unit 83, and a display unit 84 are exactly the same as the tablet 23, the tablet drive unit 24, the control unit 21, and the display unit 22 in FIG. Also, the tablet drive unit 8
The internal structure of No. 2 has the same structure as FIG. However,
The storage unit 85 in the present embodiment stores an INT signal detection routine in addition to the system initialization program, system control program, calibration program and coordinate detection program stored in the storage unit 25 in FIG. . In addition, the correction data storage area,
In addition to the pressing data storage area, the internal interrupt interval set value storage area and the work area 85a, a second internal interrupt interval set value storage area for storing the second internal interrupt interval set value is provided. Hereinafter, the internal interrupt interval set value storage area is referred to as a first internal interrupt interval set value storage area, and the first internal interrupt interval set value storage area stores the first internal interrupt interval set value. Shall be stored. Incidentally, as will be described in detail later,
The contents of the system initialization program and the system control program are changed.

The coordinate detecting device for the antireflection tablet having the above-described configuration controls the control unit 83 based on the system initialization program, system control program, calibration program, coordinate detection program, and INT signal detection routine stored in the storage unit 85. Below, the tablet control unit 82 executes coordinate detection of the pen input position. 5 and 6 are flowcharts of the pen input position detection processing operation.

Steps S91 to S95 in the flow chart of the pen input position detection processing operation are exactly the same as steps S1 to S5 in the flow chart of the pen input position detection processing operation shown in FIGS. Further, steps S97 to S106 and S108 in the flow chart of the pen input position detection processing operation are the same as steps S97 to S106 in the flow chart of the pen input position detection processing operation shown in FIGS.
This is exactly the same as 7 to step S17. However, the activation of the internal interrupt generation unit 83a executed in step S97 of the flowchart is the activation using the first internal interrupt interval setting value stored in the storage unit 85.

In addition, in the flow chart of the pen input position detection processing operation in the present embodiment, when the control unit initialization subroutine in step S94 or the calibration subroutine in step S95 is executed and the input waiting period is entered. , In step S96, the storage unit 85
Based on the INT signal detection routine stored in
The signal detection subroutine is executed. This INT
In the signal detection subroutine, each terminal X of the tablet 81
While inverting the levels of the voltages applied to H, XL, YH, and YL at predetermined intervals, it is detected that the INT signal level becomes "L" and the pen input is started. Therefore, when entering the input waiting period, each terminal X of the tablet 81
In order to set the timing of inverting the voltage levels applied to H, XL, YH, and YL, the internal interrupt generation unit 83a stopped in step S106 is set to step S107.
Then, the system is restarted using the second internal interrupt interval setting value stored in the storage unit 85.

Next, the control unit initialization subroutine executed in the calibration subroutine in step S94 or step S95 in the flow chart of the pen input position detection processing operation will be described.
FIG. 7 is a flowchart of the control part initialization subroutine. When it is determined that there is correction data in the storage section 85 in step S93 of the flow chart of the pen input position detection processing operation, or
When the calibration subroutine is entered at 95, the controller initialization subroutine is started.

In step S111, in order to set the timing of inverting the level of the voltage applied to each terminal XH, XL, YH, YL of the tablet 81, the internal interrupt interval setting value is used to set the internal interrupt. The inclusion generating unit 83a is activated. In this way, the internal interrupt processing of the voltage application to the tablet 81 becomes possible at the second time interval set based on the second internal interrupt interval setting value. Step S
At 112, the level of the output port XH0 of the control unit 83 is set to "H", while the other output ports XL0,
The levels of XL1, YH0, YL0, and YL1 are set to "L", and the control unit initialization subroutine ends. Then, the process returns to the calibration subroutine of step S96 or step S95 in the main routine of the pen input position detection processing operation. As a result, only the terminal XH is connected to the power source Vcc, and the tablet 81 waits for a pen input.

Next, the INT signal detection subroutine executed in step S96 in the flow chart of the pen input position detection processing operation will be described in detail. FIG. 8 is a flowchart of the INT signal detection subroutine. When the control unit initialization subroutine in step S94 or the calibration subroutine in step S95 in the flow chart of the pen input position detection processing operation is completed and the input waiting period starts, I
The NT signal detection subroutine starts.

In step S121, it is determined whether or not the level of the INT signal sent from the coordinate detection switch in the tablet drive section 82 is "L". As a result, when it becomes "L" and it is detected that there is a pen input, the process proceeds to step S128, and otherwise, the process proceeds to step S122. In step S122, it is determined whether or not there is an internal interrupt from the internal interrupt generator 83a at the second time interval. As a result, if there is, go to step S123. In step S123, the level of the output port XH0 is set to "L" and the terminal XH is separated from the power supply Vcc. In step S124, the level of the output port YH0 is set to "H" and the terminal YH is connected to the power supply Vcc.

In step S125, the internal interrupt generation unit 8
It is determined whether there is an internal interrupt at the second time interval from 2a. As a result, if there is, the process proceeds to step S126. In step S126, the level of the output port YH0 is set to "L" and the terminal YH is separated from the power supply Vcc. In step S127, the level of the output port XH0 is set to "H" and the terminal XH is connected to the power supply Vcc, and then the process returns to step S121.

Thus, in step S121, I
The above steps S122 to S127 are repeated until it is determined that the level of the NT signal has become "L". When it is determined that the level of the INT signal has become "L", the process proceeds to step S128. In step S128, the operation of the internal interrupt generation unit 83a is stopped and the INT signal detection subroutine ends. Then, the process returns to step S97 in the main routine of the pen input position detection processing operation.

If there is a pen input while the INT signal detection subroutine is being executed, the pen input is detected in step S121. Normally, the time for which the pen continues to press the tablet 81 is 100 msec or more. Therefore, in order to reliably detect the pen input in step S121, the processing time from step S121 to step S127 needs to be shorter than 100 msec. Therefore, the second internal interrupt interval setting value may be shorter than 50 msec.

FIG. 9 is a timing chart when the pen input position detecting process is executed by the coordinate detecting device for the antireflection tablet having the above-described configuration. From FIG. 9, the second
Terminals XH and YL are synchronized with internal interrupts at time intervals.
It can be seen that the application direction of the voltage applied between and the application direction of the voltage applied between the terminals YH and XL are reversed.

In this embodiment, the level of the INT signal becomes "L" when the level of the output port YHO becomes "H" and the terminal YH is connected to the power supply V _CC . However, at that time, the INT signal level is not discriminated (it is executed in step S121 only when the level of the output port XHO becomes "H" in step S127). Therefore, the process does not proceed to step S128.

If there is a pen input at the time point A, the coordinate detection switch is kept on for 100 msec or longer. Therefore, at the time point B, the second step in step S125 is performed.
Even if the power supply voltage Vcc is applied to the terminal XH0 in step S127 based on the detection of the internal interrupt at the time interval, IN
The level of the T signal does not become "H". As a result, the pen input can be detected in the next step S121. The first time interval in the figure is a time interval for coordinate detection set based on the first internal interrupt interval setting value stored in the storage unit 85.

As described above, in the present embodiment, when inverting the level of the voltage applied to the tablet 81 during the input waiting period and the first internal interrupt interval set value used in detecting the coordinates in the storage section 85, The second internal interrupt interval setting value to be used is stored. When the input waiting period is entered, the INT signal detection subroutine using the INT signal detection routine stored in the storage unit 85 is executed. Then, the level of the voltage applied to each terminal XH, XL, YH, YL of the tablet 81 is inverted at the second time interval based on the second internal interrupt interval setting value.

Therefore, as in the first embodiment, the above I
Step S123 in the NT signal detection subroutine,
By S124, a DC voltage is applied from the lower conductive film to the upper conductive film (see FIG. 3 (b)), and the above step S126,
By S127, a DC voltage is applied from the upper conductive film to the lower conductive film (see FIG. 3 (a)). As a result, the voltage applied to the antireflection liquid enclosed between the transparent film of the tablet 81 and the glass can be converted into an alternating current, and the deterioration of the antireflection liquid and the conductive film due to electrolysis can be prevented. Therefore, it becomes possible to mix an electrolytic substance such as alcohol or water into the antireflection liquid.

According to the present embodiment, the system initialization program and the system control program stored in the storage unit 25 of the conventional analog type tablet coordinate detecting apparatus shown in FIG.
The conventional tablet drive unit shown in FIG. 30 can be used as it is by simply adding a signal detection routine and expanding the internal interrupt interval set value storage area. Therefore, the development cost can be reduced.

<Third Embodiment> In this embodiment, the purpose of not applying a DC voltage to the antireflection liquid sealed in the tablet during the coordinate detection period is to be achieved by hardware. The anti-reflection tablet coordinate detection device in this embodiment detects the input coordinates in the above-mentioned analog type tablet, and the basic configuration thereof is the same as the configuration shown in FIG. 29. , Tablet drive unit, control unit, display unit and storage unit.
The tablet, the control unit, the display unit, and the storage unit have the same configuration as the tablet 23, the control unit 21, and the display unit 2 shown in FIG.
2 and the storage unit 25, the detailed description thereof will be omitted.

FIG. 10 is a block diagram of the tablet driving section in the coordinate detecting device for the antireflection tablet of this embodiment. The tablet driving unit is a switch 96a which operates similarly to the case of the tablet driving unit shown in FIG.
96d, 97a, 97b, resistors 98a, 98b, A / D converter 99, coordinate detection switch 100, pull-down resistor 10
1, a power-on switch 102, and a drive control unit 103.

Further, the tablet drive section in the present embodiment gives a changeover switch 104a for switching the terminal XH and the terminal XL, a changeover switch 104b for switching the terminal YH and the terminal YL, and a timing for inverting the voltage applied to the tablet 91. Inverter 105 and D flip-flop (hereinafter abbreviated as D-FF) 10 for
6, an inverter 107 for inverting the level of the output signal of the A / D converter 99, and a drive control as digital data by selecting either the output signal of the A / D converter 99 or the inverted signal from the inverter 107 It has a selection switch 108 for sending to the unit 103.

FIG. 11 is a timing chart when the pen input position detecting process is executed by the coordinate detecting device for the antireflection tablet having the above structure. Hereinafter, the pen input position detecting operation by the coordinate detecting device of the antireflection tablet will be described with reference to FIGS. 10 and 11. FIG.
As shown in the procedure of No. 1, X is pressed in one coordinate detection operation.
(Dummy conversion)-> X coordinate detection-> Y press-> Y coordinate detection. When the Y coordinate detection, which is the final coordinate detection operation in one coordinate detection operation, is performed, the switch 9
Since 6d is turned on and the terminal YL is grounded, the level of the output port YL0 of the drive control unit 103 becomes "H".

Therefore, in the present embodiment, the end of one coordinate detection operation is detected by detecting the level rise of the output port YL0 by the inverter 105 and the D-FF 106. Then, the D-FF 106 inverts the level every time the level of the output port YL0 falls, and generates the control signal REV for controlling the inversion of the voltage applied to the tablet 91. The above D-
The FF 106 is reset when the level of the output port PON becomes “L” and the power-on switch 102 is turned off, and stabilizes the output level.

By simultaneously switching the changeover switches 104a and 104b and the selection switch 108 according to the level of the control signal REV generated in this way, application to the upper conductive film or the lower conductive film forming the tablet 91 is performed. The application direction of the applied voltage is switched. As a result, even in the antireflection liquid sealed between the upper conductive film and the lower conductive film, the direction of the applied voltage is switched in the region close to each conductive film.

For example, considering a case where the point K on the tablet 91 is continuously pressed, in the state shown in FIG. 10, the X-coordinate detection operation is equivalent to the circuit shown in FIG. The voltage V ₁ is sent from the terminal YL to the A / D converter 99 to obtain digital data representing the pen input position. On the other hand, at the time of the Y coordinate detection operation, the circuit becomes equivalent to the circuit shown in FIG.
The voltage V ₂ is delivered to the converter 99. When the level of the control signal REV is inverted in this state, it becomes equivalent to the circuit shown in FIG. 12 (c) during the X coordinate detection operation, and the voltage V ₁ 'is sent from the terminal YL to the A / D converter 99. It On the other hand, Y
In the coordinate detecting operation, the circuit becomes equivalent to the circuit shown in FIG. 12D, and the voltage V ₂ 'is sent from the terminal XL to the A / D converter 99.

Here, as described above, the level of the control signal REV is inverted every one coordinate detection operation. Therefore, when the pen input is detected and the coordinate detection period is entered, the above-mentioned equivalent circuit becomes 12 (a) → 12 (b) → 12 (c) → 12 (d) → 1
It switches to 2 (a) → ...

At this time, ignoring the internal resistance of each switch, V ₁ '= Vcc-V ₁ and V ₂ ' = Vcc-V ₂ . Therefore, when the level of the control signal REV becomes “H” and the terminal XL or the terminal YL is connected to the power supply Vcc (see FIG. 1).
2 (c) and the equivalent circuit of FIG. 12 (d)), the control signal RE
The selection switch 108 is switched by V, the inverter 107 selects a signal obtained by inverting the output signal of the A / D converter 99, and the signal is sent to the drive control unit 103 as digital data representing the pen input position.

If the selection switch 108 is a set of a plurality of selection switches, the A / D converter 99 can handle the parallel transfer type A / D converter. In other words, if the A / D converter 99 is a serial transfer system, 1
One selection switch 108 is sufficient, and when the A / D converter 99 is, for example, a 10-bit parallel transfer system, the selection switch 108 may be 10 selection switches.

The following can be seen from the timing chart of FIG. That is, the voltage application direction between the terminals XH and XL at the time of the procedure "X coordinate detection", and the procedure "Y
The voltage application direction between the terminals YH and YL at the time of "coordinate detection" is inverted in synchronization with the level inversion of the control signal REV.
Further, the voltage application direction between the terminals XH and XL during the procedure "X pressing" and the voltage application direction between the terminals YH and YL during the procedure "Y pressing" are also synchronized with the level inversion of the control signal REV. And flip. However, the absolute value of the potential difference varies depending on the position of the pressed point on the tablet 91.

As described above, in the tablet drive unit of this embodiment, the inverter 105 and the D-FF 106 synchronize with the falling of the level of the output port YL0 of the drive control unit 103 (end of one coordinate detection). And generates a control signal REV whose level is inverted. Then, the application direction of the voltage applied to the tablet 91 is inverted in synchronization with the level inversion of the control signal REV. Therefore, the application direction of the voltage applied to the upper conductive film or the lower conductive film forming the tablet 91 can be switched for each coordinate detection, and the upper conductive film and the lower conductive film can be switched. Even in the antireflection liquid sealed between the conductive films, the direction of the applied voltage can be switched in the region close to each conductive film. As a result, it is possible to prevent the DC voltage from being continuously applied in one direction to the antireflection liquid during the coordinate detection period.

<Fourth Embodiment> This embodiment relates to correction of detected coordinates in the coordinate detecting device for the antireflection tablet of the third embodiment. As shown in FIG. 13, the basic configuration of the coordinate detection device for the antireflection tablet in this embodiment is an analog type tablet (hereinafter, simply referred to as a tablet) 111, a tablet drive unit 112, and a control unit 11.
3, a display unit 114 and a storage unit 115. The configuration of the tablet 111, the tablet drive unit 112, the control unit 113, and the display unit 114 is exactly the same as that of the tablet 91, the tablet drive unit, the control unit 103, and the display unit in the third embodiment, and particularly the tablet drive unit. 1
The operation 12 is as described in the third embodiment.

In the storage unit 115 in this embodiment, the third
In addition to the correction data storage area, the pressing data storage area, the internal interrupt interval set value storage area and the work area provided in the storage unit (that is, the storage unit 25 in FIG. 29) in the embodiment, the second correction data is added. A second correction data storage area for storing is provided. Hereinafter, the correction data storage area is referred to as a first correction data storage area, and the first correction data is stored in the first correction data storage area. The area name "0" is given to the first correction data storage area, while the area name "1" is given to the second correction data storage area.

Further, in the work area 115a, in addition to the input position storage area, the input designated point counter storage area, and the detected coordinate storage area, the second input composed of four representative points used when the calibration program is executed. A second input position storage area for storing the position and a correction data pointer storage area are provided. Hereinafter, the input position storage area is referred to as a first input position storage area, and the first input position composed of four representative points is stored in the first input position storage area. A correction data pointer Gc is set in the correction data pointer storage area. Further, as will be described in detail later, the contents of the system initialization program, system control program, and calibration program are changed.

The coordinate detecting device for the antireflection tablet having the above-described configuration is based on the system initialization program, the system control program, the calibration program and the coordinate detection program stored in the storage unit 115.
Under the control of No. 3, the tablet control unit 112 executes the coordinate detection of the pen input position. 14 and 15 are flowcharts of the pen input position detection processing operation.

32. Steps S131 to S139 in the flow chart of this pen input position detection processing operation are shown in FIG.
33. Also, this is exactly the same as steps S1 to S9 in the flowchart of the pen input position detection processing operation shown in FIG. Further, steps S142 to S148 in the flow chart of the pen input position detection processing operation.
Is exactly the same as steps S11 to S17 in the flow chart of the pen input position detection processing operation shown in FIGS.

Further, in this embodiment, in step S140 in the flowchart of the pen input position detection processing operation, the first or second correction data stored in the correction data storage area designated by the correction data pointer Gc. Is used to correct the detected coordinates obtained in the coordinate detection subroutine of step S138. Thus, when the correction of the detected coordinates is completed, step S141
Then, the contents of the correction data pointer Gc are inverted. That is, when the content of the correction data pointer Gc is "0", the detected coordinates are corrected using the first correction data in the first correction data storage area to which the area name "0" is given. After that, the content of the correction data pointer Gc is inverted to "1". As a result, the second correction data is used in the next correction of the detected coordinates.

As described above, in this embodiment, when the coordinate of the pen input position is detected by reversing the level of the voltage applied to the tablet 111 every time the coordinate is detected,
The detected coordinates are corrected using different correction data depending on whether the power source Vcc is connected to the terminal XH or the terminal YH and the power source Vcc is connected to the terminal XL or the terminal YL. Therefore, even if the resistance value R _H of the circuit on the terminal XH side or the terminal YH side is different from the resistance value R _L of the circuit on the terminal XL side or the terminal YL side, the detected coordinates can be corrected correctly. .

FIG. 16 is a flowchart of the control unit initialization subroutine executed in the calibration subroutine in step S134 or step S135 in the flowchart of the pen input position detection processing operation. In the flowchart of the control unit initialization subroutine, in step S152, the output ports XH0, XL0, XL1, YH0, Y of the control unit 113 are processed in the same manner as step S41 in the control unit initialization subroutine shown in FIG.
Prior to setting the voltage levels of L0 and YL1, in step S151, the correction data pointer Gc used in the pen input position detection processing operation is set to "0" for initialization.

FIG. 17 is a flow chart of the calibration subroutine executed in step S135 in the flow chart of the pen input position detection processing operation. The tablet drive unit 112 in the present embodiment is the third
As described in the embodiment, during the coordinate detection period, the application direction of the voltage applied to the upper conductive film and the lower conductive film of the tablet 111 is reversed every time the coordinate is detected. Therefore, as described above, the storage unit 115
Corresponding to the above two application directions, the first and second 2
It is necessary to store one correction data. Therefore, in this calibration subroutine, the first correction data and the second correction data are obtained.

Steps S161 to S167 in the flow chart of this calibration subroutine are
This is exactly the same as steps S21 to S27 in the flowchart of the calibration subroutine shown in FIG. Furthermore, steps S172 to S175 in the flowchart of the present calibration subroutine are exactly the same as steps S28 to S31 in the flowchart of the calibration subroutine shown in FIG.

At this time, in the coordinate detection executed in step S165, the level of the control signal REV is "L".
Therefore, the equivalent circuit shown in FIGS. 12 (a) and 12 (b) is executed. Then, in step S167, the coordinates of the detected pen input position are stored in the nth point of the first input position storage area in the work area 115a of the storage unit. In addition, the above step S174
In, the first correction data used when the terminal XH or the terminal YH of the tablet 111 is connected to the power supply Vcc is calculated by a predetermined method. Since the first correction data is used when the content of the correction data pointer Gc is "0" in the pen input position detection processing operation, the first correction data is stored in the storage unit 115 in step S175. It is stored in the first correction data storage area given the name "0".

Further, in the flow chart of this calibration subroutine, the second subroutine is performed as follows.
Obtain correction data. That is, in step S168, it is determined whether or not the level of the INT signal is "L". As a result, if it is "L", the process proceeds to step S169, and if not, the process returns to step S164 to redo the coordinate detection. In step S169, the coordinate detection subroutine is executed again. At that time, the level of the control signal REV is inverted as described above when the Y coordinate is detected when the coordinate detection subroutine is executed in step S165. Therefore, the coordinate detection subroutine in this step is executed by the equivalent circuit shown in FIGS. 12 (c) and 12 (d).

In step S170, it is determined whether or not the result of the coordinate detection executed in step S169 is good. If the result is good, the process proceeds to step S171,
If not, the process returns to step S164 and the coordinate detection is performed again. In step S171, the coordinates of the pen input position detected in step S169 are the n-th position of the second input position storage area in the work area 115a of the storage unit 115.
Stored at the points.

Further, in step S176, the terminal XL or the terminal YL of the tablet 111 is powered on the basis of the coordinates of the pen input positions associated with the four representative points stored in the second input position storage area in step S171. The second correction data used when connected to Vcc is calculated by a predetermined method. In step S177, the second correction data calculated in step S176 is the correction data pointer Gc in the pen input position detection processing operation.
Is used when the content of "1" is "1", the second correction data is stored in the second correction data storage area given the area name "1" in the storage unit 115.

Thus, the first correction data used when the terminal XH or the terminal YH in the tablet 111 is connected to the power supply Vcc to execute the coordinate detection, and the terminal XL or the terminal YL is connected to the power supply Vcc to detect the coordinate. That is, the second correction data to be used when executing is obtained.

<Fifth Embodiment> In the present embodiment, the purpose of not continuously applying a DC voltage to the antireflection liquid enclosed in the matrix type tablet is achieved by hardware. The basic configuration of the coordinate detecting device for the antireflection tablet in this embodiment is the same as that shown in FIG. 40, and includes a 4 × 4 matrix type tablet (hereinafter, simply referred to as a tablet), a control unit, a display unit and a storage unit. Become. The configuration of the tablet, the display unit, and the storage unit is as shown in FIG.
2 and the storage unit 44, the detailed description thereof is omitted.

FIG. 18 is a block diagram of the tablet drive section provided in the control section in the coordinate detecting apparatus for the antireflection tablet of this embodiment. The tablet drive section has a drive control section 122 and a device protection resistor 123 that operate in the same manner as the tablet drive section shown in FIG.

Further, in the tablet driving unit in the present embodiment, the inverter 125a for generating the inverted signal of the strobe signal output from the output ports S0 to S3 of the drive control unit 122, and the data signal representing the input position from the tablet 121. An inverter 125b that generates an inverted signal of
A selector switch 126a for selectively selecting and outputting either the strobe signal or its inverted signal, a selector switch 126b for selectively selecting and outputting either the data signal or its inverted signal, and selector switches 126a, 12a.
It has a D-FF 127 that determines the switching cycle of 6b, a pull-up / pull-down switch 128 that sets the reference level of the data signal, and a resistor 124 that stabilizes the level of the data signal when not input.
In the present embodiment, the changeover switches 126a, 1a
A multiplexer is used as 26b.

The tablet drive unit having the above structure operates as follows. That is, the voltage of the output ports S0 to S3 of the drive control unit 122 is sequentially raised to a level "H" at a constant interval, the tablet 121 is scanned, and the voltage of the input ports D0 to D3 is read each time, so that the tablet is read. The pressed position on 121 is detected. At that time, an inverted signal of each strobe signal is generated by the inverter 125a, and each strobe signal and its inverted signal are input to the changeover switch 126a.
Similarly, an inverted signal of each of the above data signals is output from the inverter 12
Each strobe signal and its inverted signal generated by 5b are input to the changeover switch 126b.

The level of the voltage applied to the upper strip-shaped conductive film constituting the tablet 121 is inverted by switching and selecting the strobe signal or its inverted signal with the changeover switch 126a. Further, the pull-up / pull-down changeover switch 12 connected to the lower strip-shaped conductive film via the resistor 124.
By switching and selecting the power source Vcc side or the ground side at 8, the reference level of the voltage applied to the lower conductive film is inverted. The changeover switch 126b determines which of the data signal and its inverted signal is valid. The changeover switch 126a,
126b and pull-up / pull-down switch 12
8 is switched by level inversion of the control signal CONT.

The period for inverting the voltage level applied to each conductive film of the tablet 121 is set such that the falling edge of the strobe signal output from the output port S3 of the drive control unit 122 when the last row of the tablet 121 is scanned. Based on, set as follows. That is, the strobe signal from the output port S3 is inverted by the inverter 125a, and the control signal CONT whose level is inverted in synchronization with the fall of the strobe signal by the D-FF 127 which uses the inverted signal as a clock.
Is generated.

When the tablet 121 is not pressed (that is, when no input is made), as described above, all the data signals from the lower conductive films of the tablet 121 are pulled up. The pull-down switch 128 fixes the level to either "H" or "L". At this time, when the changeover switch 126a selects the strobe signal and sends it to the tablet 121, the level of the control signal CONT is set to "L" so that the pullup / pulldown changeover switch 128 selects the ground side. Of.

Further, by the changeover switch 126b, one of the data signal from the tablet 121 and the inverted signal thereof is selected as described above. At this time, when the changeover switch 126a selects the strobe signal and applies it to the tablet 121, the changeover switch 126b selects the control signal CO so as to select the data signal side.
The level of NT is set to "L".

By setting the level of the control signal CONT and the states of the switches 126a, 126b and 128 as described above, the level of the control signal CONT becomes "L" and the changeover switch 126a selects the strobe signal side. (The active level of the scanning signal S _i 'becomes "H")
Then, the reference level of the data signal is set to "L" by the pull-up / pull-down switch 128, and the data signal side is selected by the switch 126b (the active level of the input signal to the input ports D0 to D3 is "H"). Will be set). Therefore, the relationship between the level change of the strobe signal from each output port S0 to S3 of the drive control unit 122 and the level change of the data signal to each input port D0 to D3 is the same as that of the drive control unit 45 shown in FIG. Becomes

As a result, the system initialization program, the system control program stored in the storage unit 44 shown in FIG. 40 as the system initialization program, the system control program, and the tablet control program stored in the storage unit in this embodiment. Therefore, the same program as the tablet control program can be used.

FIG. 19 is a timing chart when the drive control unit 122 executes the input position detection processing operation under the control of the control unit. The figure shows two coordinate detections.
It is equivalent to the case of going once. From FIG. 19, the output ports S0 to S3 corresponding to the scanning rows in the drive control unit 122 are shown.
It can be seen that the level of the control signal CONT is inverted in synchronization with the fall of the strobe signal from the output port S3 when the levels of the strobe signals from 1 to 3 sequentially become "H". Further, the active level and the reference level of the scanning signal of the tablet 121 and the active level and the reference level of the data signal from the tablet 121 are inverted in synchronization with the level inversion of the control signal CONT. Therefore, it can be seen that the application direction of the voltage applied between the scan row and the column where the input position does not exist in the tablet 121 is also inverted in synchronization with the level inversion of the control signal CONT.

FIG. 20 shows the voltage applied to the tablet 121 when the input position detection processing operation is executed. When the level of the control signal CONT is “L”, as shown in FIG. 20 (a), the strip-shaped conductive film 132 formed on the transparent film 131 on the upper side of the tablet 121 is driven. Since the voltage level of the output port S _i connected to the portion 122 and connected to the conductive film 132 related to the scanning row is “H”, the upper transparent film 13
It is equivalent to that the conductive film 132 on 1 is connected to the power supply Vcc. At that time, the strip-shaped conductive film 134 formed on the lower transparent film 133 is grounded via the resistor 124.

In this state, the control signal CONT
20B, the conductive film 134 formed on the lower transparent film 133 is connected to the power supply Vcc via the resistor 124, as shown in FIG. At that time,
Since the voltage level of the output port S _i connected to the conductive film 132 related to the scanning row formed on the upper transparent film 131 is “L”, the upper transparent film 131
This is equivalent to grounding the conductive film 132 on the side.

The level of the control signal CONT is inverted each time the scanning of the tablet 121 is completed once by the fall of the strobe signal from the output port S3 of the drive control section 122, as shown in FIG. 20 (a). Equivalent circuit and Fig. 2
The equivalent circuit shown in 0 (b) will appear alternately. Therefore, the transparent film 13 on the upper side of the tablet 121
The voltage applied to the antireflection liquid 135 enclosed between 1 and the lower transparent film 133 can be converted to alternating current, and the deterioration of the antireflection liquid 135 and the conductive films 132 and 134 due to electrolysis can be prevented. .

As described above, in this embodiment, the level of the strobe signal from the drive controller 122 and the level of the data signal from the tablet 121 are inverted by the inverter 125a or the inverter 125b. Further, the final output port S in the drive control unit 122
Falling of strobe signal from 3 (end of one scan)
The control signal CONT whose level is inverted every time is set to D-FF12.
Generate in 7. The changeover switches 126a and 126b and the pull-up / pull-down changeover switch 128 are changed over in synchronization with the level inversion of the control signal CONT.

Therefore, each of the output ports S0 to S3 is
To send the strobe signal from the tablet 121 to the tablet 121, the reference level of the data signal is set to "L", and the data signal is input to the input ports D0 to D of the drive control unit 122.
Send to 3. On the other hand, when the inverted signal from the inverter 125a is sent to the tablet 121, the reference level of the data signal is set to "H", and the inverted signal of the data signal from the inverter 125b is input to the input ports D0 to D0 of the drive control unit 122. It can be sent to D3. As a result, the upper conductive film 1 is synchronized with the level inversion of the control signal CONT.
The direction of the voltage applied between 32 and the lower conductive film 134 can be reversed.

That is, according to the present embodiment, the voltage applied to the antireflection liquid 135 enclosed in the tablet 121 is converted into an alternating current, and the antireflection liquid 135 and the conductive film 1 are formed.
It is possible to prevent the deterioration of 32,134.

Further, according to this embodiment, the program used when executing the input position detection processing operation is as shown in FIG.
The program stored in the storage unit 44 of the conventional matrix type tablet coordinate detection device shown in 0 can be used as it is. Therefore, the development cost can be reduced.

<Sixth Embodiment> The coordinate detecting device for an antireflection tablet according to this embodiment detects the input coordinates in the matrix type tablet, and its basic configuration is as shown in FIG.

In FIG. 21, a matrix type tablet (hereinafter simply referred to as a tablet) 141 and a display section 143 are exactly the same as the tablet 43 and the display section 42 in FIG. Further, the tablet drive unit provided in the control unit 142 has a structure as shown in FIG. Further, the storage unit 145 is provided with an inversion flag storage area in addition to the input position storage area and the row counter storage area provided in the work area 44a in FIG. As will be described later in detail, the contents of the tablet control program stored in the storage unit 145 are changed.

In FIG. 22, the tablet driving unit in the coordinate detecting apparatus for the antireflection tablet of this embodiment has a device protection resistor 147 that operates similarly to the tablet driving unit shown in FIG. The tablet 141 described above
A resistor 148 is connected to the strip-shaped conductive film formed on the lower transparent film, and the side of the resistor 148 opposite to the tablet 141 is connected to the extra output port REV of the drive controller 146. .

The coordinate detecting device for the antireflection tablet having the above-described configuration is operated by the drive control unit 146 under the control of the control unit 142 based on the tablet control program stored in the storage unit 145. Will be described in detail. FIG. 23 is a flowchart of the input position detection processing operation. When the power of the control unit 142 is turned on, the input position detection processing operation starts.

In step S181, the internal interrupt generation section 142a in the control section 142 is activated. Thus
The internal interrupt processing of the input position detection processing becomes possible at the time interval set based on the internal interrupt interval setting value stored in the storage unit 145. In step S182, "0" is set to the inversion flag R set in the inversion flag storage area in the work area 145a. In step S183, it is determined whether or not the content of the inversion flag R is "0". If the result is "0", step S1
If not, the process proceeds to step S186.

At step S184, the drive control section 146 is operated.
The level of the output port REV at is set to "L". In step S185, the levels of all the output ports S0 to S3 in the drive control unit 146 are set to "L", and the row counter i set in the row counter storage area in the work area 145a of the storage unit 145 is set to "1". Is set and the process proceeds to step S188. In step S186, the level of the output port REV is set to "H". In step S187, all the output ports S
The levels of 0 to S3 are set to "H", and the row counter i is set to "1".

In step S188, the output ports S0 to S0
The voltage level of the i-th output port S _i of S3 is set to the same level as the inversion level of the output port REV. In step S189, the contents of the inversion flag R are
It is determined whether or not it is "0". As a result, if "0", the process proceeds to step S191, and if not, step S1.
Go to 90. In step S190, the level of each data signal fetched from the input ports D0 to D3 in the drive control unit 146 is inverted. In this way, similarly to the tablet drive unit shown in FIG. 41, the signal with the reference level "L" and the active level "H" is input to the input ports D0 to D3 of the drive unit 146.

In step S191, DATA (i) set in the i-th row of the input position storage area in the work area 145a of the storage unit 145 represents the voltage levels of all the input ports D1 to D3 during the i-row scanning. Information is stored. In step S192, the level of the i-th output port S _i is set to the same level as the output port REV, and the content of the row counter i is incremented. In step S193, it is determined whether or not the content of the row counter i is larger than the maximum value "4". As a result, if it is larger than "4", the process proceeds to step S194, and if it is "4" or less, the process returns to step S188 to start the process of the next row.

In step S194, the coordinates of the input position are obtained based on the contents of DATA (i) stored in step S191. Then, the instruction content from the user associated with the input position coordinates is confirmed. Step S
At 195, the program corresponding to the instruction content, the display of the input position on the display unit 143, and the like are executed according to the confirmation result at step S194. Here, if the user does not input to the tablet 141, the contents of DATA (i) relating to all the scanning lines are “0”, and the instruction contents are “do nothing”.

In step S196, if the content of the inversion flag R is "0", it is inverted to "1", and if it is "1", it is inverted to "0". In step S197, the internal interrupt generation unit 142a
It is determined whether or not there is a next internal interrupt from. As a result, if there is an internal interrupt, the process proceeds to step S198.
In step S198, it is determined whether or not the end of the input position detection processing operation has been instructed. As a result, if not instructed, the process returns to step S183 and the coordinate detection of the input position is continued. On the other hand, if instructed, the input position detection processing operation ends.

FIG. 25 is a timing chart when the input position detection processing operation is executed. The figure corresponds to the case where the coordinate detection is performed twice. From FIG. 25, the output port S0 corresponding to the scan row in the drive control unit 146 is
The level of the strobe signal from S3 sequentially becomes "H". Then, every time one scan is completed, the tablet 1
41, the active level and the reference level of the strobe signal, the active level and the reference level of the data signal from the tablet 141 to the drive control unit 146, and
It can be seen that the level of the output port REV of the drive control unit 146 is inverted. As a result, it can be seen that the application direction of the voltage applied between the scan row and the column where the input position does not exist in the tablet 141 is inverted in synchronization with the level inversion of the output port REV.

As described above, in the present embodiment, the work area 145a in the storage unit 145 is provided with the reversal flag R, and the content of the reversal flag R is set to "0" each time one scan of the tablet 141 is completed. And invert between "1". Then, by executing the input position detection processing operation based on the tablet control program stored in the storage unit 145, in synchronization with the inversion of the inversion flag R, the level of the strobe signal sent to the tablet 141, the drive from the tablet 141. Level of data signal to control unit 146 and output port RE of drive control unit 146
The V level is inverted.

Therefore, as in the fifth embodiment, when the content of the inversion flag R is "0", a DC voltage is applied from the upper conductive film to the lower conductive film (see FIG. 2).
0 (see 0 (a)), and when the content of the inversion flag R is "1", a DC voltage is applied from the lower conductive film to the upper conductive film (see FIG. 20 (b)). As a result, the tablet 14
The voltage applied to the antireflection liquid enclosed between the upper transparent film and the lower transparent film of 1 can be converted into an alternating current,
It is possible to prevent deterioration of the antireflection liquid or the conductive material due to electrolysis.

In the fifth and sixth embodiments, a 4 × 4 matrix tablet is described as an example for simplification of description, but the present invention is not limited to this. Needless to say. Further, each of the above-described embodiments may be implemented alone, or a plurality of embodiments may be combined. For example, the application direction of the voltage applied to the tablet may be reversed during the input waiting period and the coordinate detection period by combining the second, third and fourth embodiments. Further, the changeover switches 66, 104a, 104b, the switches 67, 68, the selection switch 108, and the pull-up / pull-down changeover switch 128 in each of the above-described embodiments are composed of semiconductor elements such as transistors.

[0164]

As is apparent from the above, in the coordinate detecting device for an antireflection tablet according to the first aspect of the present invention, the coordinate detecting unit for detecting the input coordinates on the antireflection tablet of the resistance film type is provided with the reversing means. Thus, the application direction of the voltage applied to the antireflection tablet is reversed at predetermined time intervals, so that the DC voltage is not continuously applied to the antireflection material enclosed in the antireflection tablet. Therefore,
It is possible to prevent electrolysis between the conductive film or the substrate material and the antireflection material. That is, according to the present invention, an inexpensive electrolytic substance such as water or alcohol can be used as the antireflection material, and the cost can be reduced.

Further, in the coordinate detecting device for an antireflection tablet according to a second aspect of the present invention, the antireflection tablet is an analog type tablet, and the tablet drive section constituting the coordinate detection section has a first switching circuit. And providing a second switching circuit and a control signal generating circuit,
During the input waiting period, since the conductive film for applying a predetermined voltage and the conductive film to be grounded in the antireflection tablet are switched to the upper conductive film and the lower conductive film,
As the control unit for controlling the operation of the tablet driving unit, the control unit in the conventional coordinate detecting device for the antireflection tablet can be used as it is. Therefore, according to the present invention, it is possible to further inexpensively provide the coordinate detecting device of the analog type antireflection tablet in which the DC voltage is not continuously applied to the antireflection material during the input waiting period.

Further, in the coordinate detecting device for an antireflection tablet according to a third aspect of the present invention, the antireflection tablet is an analog type tablet, and the control section constituting the coordinate detecting section is a clocking means and a voltage switching means. Has
During the input waiting period, the conductive film for applying a predetermined voltage in the antireflection tablet is switched between the upper conductive film and the lower conductive film, so that the tablet drive unit controlled by the control unit has been conventionally used. The tablet drive unit in the coordinate detection device of the antireflection tablet can be used as it is. Therefore, according to the present invention, it is possible to further inexpensively provide the coordinate detecting device of the analog type antireflection tablet in which the DC voltage is not continuously applied to the antireflection material during the input waiting period.

Further, in the coordinate detecting device for an antireflection tablet according to a fourth aspect of the present invention, the antireflection tablet is an analog type tablet, and the tablet drive section has a first switching circuit, a second switching circuit and a second switching circuit. By providing a control signal generation circuit, during the coordinate detection period,
While reversing the place where a predetermined voltage is applied and the place where it is grounded in the upper conductive film of the antireflection tablet, the place where a predetermined voltage is applied and the place where it is grounded in the lower conductive film are reversed. Therefore, as the control unit for controlling the tablet driving unit, the control unit in the conventional coordinate detecting device for the antireflection tablet can be used as it is. Therefore, according to the present invention, it is possible to further inexpensively provide the coordinate detection device of the analog type antireflection tablet in which the DC voltage is not continuously applied to the antireflection material during the coordinate detection period.

Further, in the coordinate detecting device for an antireflection tablet according to the present invention, the antireflection tablet is a matrix type tablet, and the tablet driving section constituting the coordinate detecting section has an inverter circuit, 1
A switching circuit, a second switching circuit, and a control signal generating circuit are provided to send an inverted signal obtained by inverting the voltage signal applied to the conductive film in the row direction of the antireflection tablet by the inverter circuit to the antireflection tablet. While a predetermined voltage is applied to the conductive film in the column direction, the conductive film in the column direction is grounded when the voltage signal is sent to the antireflection tablet. Can use the control unit of the conventional coordinate detection device of the antireflection tablet as it is.
Therefore, according to the present invention, a coordinate detecting device for a matrix type antireflection tablet in which a DC voltage is not continuously applied to the antireflection material can be provided at a lower cost.

According to a sixth aspect of the present invention, there is provided a coordinate detecting device for an antireflection tablet, wherein the antireflection tablet is a matrix type tablet, and the control section constituting the coordinate detecting section includes a time measuring means and a voltage inverting means. Each time the conductive film in the row direction is scanned once for the level of the voltage applied to the conductive film in the row direction and the level of the voltage applied to the conductive film in the column direction in the antireflection tablet. The tablet drive unit controlled by the control unit can directly use the tablet drive unit in the conventional coordinate detecting device for the antireflection tablet. Therefore, according to the present invention, a coordinate detecting device for a matrix type antireflection tablet in which a DC voltage is not continuously applied to the antireflection material can be provided at a lower cost.

[Brief description of drawings]

FIG. 1 is a block diagram of a tablet drive unit in an embodiment of a coordinate detection device for an antireflection tablet according to the present invention.

FIG. 2 is a timing chart when executing a pen input position detection processing operation by the tablet drive section shown in FIG.

FIG. 3 is an explanatory diagram of a voltage applied to the tablet in FIG. 1 when waiting for input.

FIG. 4 is a schematic block diagram of a coordinate detection device for an antireflection tablet different from that in FIG.

5 is a flowchart of a pen input position detection processing operation executed by the tablet drive unit in FIG.

FIG. 6 is a flowchart of pen input position detection processing operation subsequent to FIG. 5;

FIG. 7 is a flowchart of a control unit initialization subroutine executed in FIG.

FIG. 8 is a flowchart of an INT signal detection subroutine executed in FIG.

9 is a timing chart when a pen input position detection processing operation is executed by the tablet drive unit in FIG.

FIG. 10 is a block diagram of a tablet driving unit in a coordinate detecting device for an antireflection tablet, which is different from FIGS. 1 and 4.

FIG. 11 is a timing chart when a pen input position detection processing operation is executed by the tablet driving section shown in FIG.

12 is an explanatory diagram of a voltage applied to a tablet when a pen input position detection processing operation is executed by the tablet drive unit shown in FIG.

FIG. 13 is a schematic block diagram of a coordinate detection device for an antireflection tablet different from those in FIGS. 1, 4, and 10.

14 is a flowchart of a pen input position detection processing operation executed by the tablet driving section in FIG.

FIG. 15 is a flowchart of pen input position detection processing operation subsequent to FIG. 14;

16 is a flowchart of a control unit initialization subroutine executed in FIG.

FIG. 17 is a flowchart of a calibration subroutine executed in FIG.

FIG. 18 is a block diagram of a tablet drive unit in a coordinate detecting device for an antireflection tablet, which is different from FIGS. 1, 4, 10 and 13.

19 is a timing chart when the input position detection processing operation is executed by the tablet drive section shown in FIG.

20 is an explanatory diagram of a voltage applied to the tablet when the input position detection processing operation is executed by the tablet driving section shown in FIG.

FIG. 21 is a schematic block diagram of a coordinate detection device for an antireflection tablet, which is different from FIGS. 1, 4, 10, 13, and 18.

22 is a block diagram of the tablet drive unit in FIG. 21. FIG.

23 is a flowchart of an input position detection processing operation executed by the drive control unit in FIG.

FIG. 24 is a flowchart of the input position detection processing operation subsequent to FIG. 23.

FIG. 25 is a timing chart when an input position detection processing operation is executed by the drive control unit in FIG. 22.

FIG. 26 is an explanatory diagram of a transparent touch input device.

FIG. 27 is an explanatory diagram of an analog type tablet.

FIG. 28 is an explanatory diagram of a matrix type tablet.

FIG. 29 is a schematic block diagram of a conventional analog tablet coordinate detection device.

30 is a block diagram of the tablet drive unit in FIG. 29. FIG.

31 is an explanatory diagram of voltages applied to the tablet when the pen input position detection processing operation is executed by the drive control unit in FIG. 30. FIG.

32 is a flowchart of a pen input position detection processing operation executed by the drive control unit in FIG. 30.

FIG. 33 is a flowchart of pen input position detection processing operation following FIG. 32.

34 is a flowchart of the calibration subroutine executed in FIG. 32.

FIG. 35 is a flowchart of a control unit initialization subroutine executed in FIG. 32.

36 is a flowchart of a coordinate detection subroutine executed in FIG.

37 is a flowchart of the coordinate detection subroutine following FIG. 36.

38 is a timing chart when the pen input position detection processing operation is executed by the tablet drive section shown in FIG. 30. FIG.

39 is an explanatory diagram of voltages applied to the tablet when the pen input position detection processing operation is executed by the tablet drive section shown in FIG. 30. FIG.

FIG. 40 is a schematic block diagram of a coordinate detection device for a conventional matrix-type tablet.

41 is a block diagram of a tablet drive unit provided in the control unit in FIG. 40. FIG.

42 is a timing chart when the input position detection processing operation is executed by the tablet drive section shown in FIG. 41. FIG.

43 is a flowchart of an input position detection processing operation executed by the drive control unit in FIG. 41.

44 is an explanatory diagram of a voltage applied to the tablet when the input position detection processing operation is executed by the tablet drive section shown in FIG. 41. FIG.

[Explanation of symbols]

51, 81, 91, 111 ... Analog type tablets,
59, 99 ... A / D converter, 60, 100 ... Coordinate detection switch, 63, 103, 122, 146 ... Drive control section, 83, 105, 113, 142 ... Control section, 66, 10
4a, 104b, 126a, 126b ... Changeover switch, 56a-
56d, 67, 68, 96a to 96d ... Switches, 69, 71,
107, 125a, 125b ... Inverter, 72 ... Counter, 73 ... OR gate, 76, 13
5 ... Anti-reflection liquid, 82, 112 ... Tablet drive unit, 83a, 113a, 142a ... Internal interrupt generation unit,
84,143 ... Display unit, 85,115,145 ... Storage unit, 85a, 115a, 145a ... Work area,
106, 127 ... D-FF, 108 ... Selection switch, 121, 141 ... Matrix type tablet, 122, 146 ... Drive unit, 128 ... Pull-up / pull-down changeover switch.

Claims (6)

[Claims] 1. A substrate having a transparent conductive film formed on one surface thereof is laminated with the conductive film sides facing each other with a predetermined gap, and the two substrates have a refractive index of the two substrates. A coordinate detecting device for an antireflection tablet, wherein a coordinate detecting unit detects an input coordinate on the antireflection tablet by using an antireflection tablet of a resistance film type in which an antireflection material having a close refractive index is enclosed. The coordinate detecting device for an antireflection tablet, wherein the unit has an inverting means for inverting the application direction of the voltage applied to the antireflection tablet at intervals of a predetermined time. 2. The coordinate detecting device for an antireflection tablet according to claim 1, wherein the antireflection tablet is an analog type tablet in which the conductive film is uniformly formed on one surface of the substrate, The coordinate detection unit has a tablet drive unit that drives the antireflection tablet and a control unit that controls the operation of the tablet drive unit. The tablet drive unit applies a predetermined voltage in the antireflection tablet. A first switching circuit that switches the conductive film to an upper conductive film and a lower conductive film; and a conductive film that is grounded in the antireflection tablet,
A second switching circuit for switching between the lower conductive film and the upper conductive film, and the first switching circuit and the second switching circuit for the predetermined time during an input waiting period for waiting an input to the antireflection tablet. A coordinate detection device for an antireflection tablet, comprising a control signal generation circuit that generates a control signal for switching control at intervals. 3. The coordinate detection device for an antireflection tablet according to claim 1, wherein the antireflection tablet is an analog type tablet in which the conductive film is uniformly formed on one surface of the substrate, The coordinate detection unit includes a tablet drive unit that drives the antireflection tablet and a control unit that controls the operation of the tablet drive unit, and the control unit measures the predetermined time and the predetermined time. A time measuring means for outputting a signal representing the interval of the predetermined time each time elapsed, and a conductive film for receiving a signal from the time measuring means and applying a predetermined voltage in the antireflection tablet during the input waiting period. A coordinate detection device for an antireflection tablet, comprising a voltage switching means for switching between an upper conductive film and a lower conductive film. 4. The coordinate detecting device for an antireflection tablet according to claim 1, wherein the antireflection tablet is an analog type tablet in which the conductive film is uniformly formed on one surface of the substrate, The coordinate detection unit includes a tablet drive unit that drives the antireflection tablet and a control unit that controls the operation of the tablet drive unit. The tablet drive unit includes a conductive film on the upper side of the antireflection tablet. A first switching circuit for reversing a location to which a predetermined voltage is applied and a location to be grounded by a terminal provided at one end in one direction and a terminal provided at the other end in the one direction, A portion of the conductive film below the antireflection tablet to which the predetermined voltage is applied and a portion to be grounded are provided at one end portion in the other direction orthogonal to the one direction. Second switching circuit for reversing the input terminal on the other end in the other direction and the input coordinate once during the coordinate detection period for detecting the input coordinate on the antireflection tablet. A coordinate detecting device for an antireflection tablet, characterized in that a control signal generating circuit for generating a control signal for switching and controlling the first switching circuit and the second switching circuit is provided for each. 5. The coordinate detection device for an antireflection tablet according to claim 1, wherein the antireflection tablet has the conductive film formed in a stripe shape on one surface of the substrate, and the two substrates are respectively formed. Is a matrix type tablet in which conductive films are laminated so as to be orthogonal to each other, and the coordinate detection unit includes a tablet drive unit that drives the antireflection tablet and a control unit that controls the operation of the tablet drive unit. The tablet drive unit has an inverter circuit that inverts the level of a voltage signal applied to the conductive films arranged in the row direction in the antireflection tablet and outputs an inverted signal, and the voltage signal. A first switching circuit for switching and selecting one of the inverted signals from the inverter circuit and sending the selected signal to the antireflection tablet; A second switching circuit for switching the conductive film arranged in the column direction in the antireflection tablet to either the predetermined voltage side or the ground side, and the last of the conductive films arranged in the row direction in the antireflection tablet. And a control signal generating circuit for generating a control signal for controlling switching between the first switching circuit and the second switching circuit based on a voltage signal applied to the conductive film scanned in the reflection. Coordinate detection device for prevention tablet. 6. The coordinate detecting device for an antireflection tablet according to claim 1, wherein the antireflection tablet has the conductive film formed in a stripe shape on one surface of the substrate, and the two substrates are respectively formed. It is a matrix type tablet in which conductive films are laminated so as to be orthogonal to each other, and the coordinate detection unit has a tablet drive unit that drives the antireflection tablet and a control unit that controls the operation of the tablet drive unit. The control unit measures the predetermined time and outputs a signal indicating an interval of the predetermined time every time the predetermined time elapses, and a signal from the time measuring unit, Alternate between the level of voltage applied to the conductive film arranged in the row direction and the level of voltage applied to the conductive film arranged in the column direction in the antireflection tablet. Coordinate detecting device antireflection tablet characterized by having a voltage reversing means for reversing.