JPH0131206B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinate detection device for detecting the position of a pen, cursor, etc. on a tablet.

The coordinate detection device includes a pen or a cursor, a device for supplying a sinusoidal voltage to the pen or the cursor,
A tablet having an X-axis base on which a detection conductor is arranged, a Y-axis base, and a coordinate area detection base on which a selector conductor is arranged; It consists of a device that determines the X and Y coordinates of a pen or cursor.

Fig. 1 is a block diagram of such a conventional coordinate detection device, Fig. 2a is a layout diagram of the detection conductor and selector conductor on the tablet shown in Fig. 1, and Fig. 2b and c are the detection with each of the above-mentioned conductors. It is a graph of detected values. In the figure, 1 is an oscillator that generates a clock pulse of a predetermined frequency, 2 is a frequency divider that divides the clock pulse of oscillator 1, 3 is a filter that converts the rectangular wave of frequency divider 2 into a sine wave, and 4 is this sine wave. The amplifier 5 is a stylus pen having a coil 6 to which an amplified sine wave is supplied. 7 is X
This tablet consists of bases for axis, Y-axis, and coordinate area detection. Figure 2a shows two detection conductors placed on the X-axis base (hereinafter, these detection conductors are referred to as cos and sin lines, respectively) and a selector conductor placed on the coordinate area detection base. There is. In addition, the cos on the Y-axis base
The arrangement of the wires and sin wires and their relationship with the selector conducting wire are the same as those of the X-axis base, but only the arrangement is different by 90 degrees, so only the X-axis will be described below.

In FIG. 2a, 8 is a cosine line, and 9 is a sine line, which are arranged in a meandering manner on the base with a phase difference of 90 degrees in electrical angle. In the figure, the cos line 8 is a solid line, and
The sin line 9 is shown as a dashed line. On the other hand, numeral 10 denotes a selector conductor wire disposed on the coordinate area detection base, and is formed in a comb-teeth shape. Selector conductor 1
0 is shown as a thick line, and the spacing of the comb teeth is
Both bases are superimposed so as to match the interval of one period between the cosine line 9 and the sine line 10, and to be arranged as shown in the figure with respect to the cosine line 9 and the sine line 10. Tc is the terminal of cos wire 8, Ts is the terminal of sin wire 9,
T ₀ to _{T 4} are terminals of each comb tooth of the selector conducting wire.

Returning to FIG. 1, 11 indicates each terminal Tc, Ts, when the stylus pen 5 is placed on the tablet 7.
A selector sequentially switches and outputs the signals generated at T ₀ to _{T 4} , amplifiers 9 and 10 amplify the signals of the cosine line and the sine line, respectively, and 14 an adder. The adder 14 is composed of a polarizing capacitor 14a and a resistor 14b, and based on the signal generated on the cosine line 9 and the signal generated on the sinine line 10, the stylus pen 5 is moved from the reference position within one cycle of the cosine line 9. outputs a sine wave with a phase difference (phase difference with respect to the sine wave output from the filter 3) corresponding to the distance between the positions where the filters are placed. 15 is an amplifier, and 16 is a comparator for determining the level of this sine wave signal. 17 is a counter that is set at the rising edge of the rectangular wave from the frequency divider 2 and reset by the signal from the comparator 16, and a clock pulse from the oscillator 1 is introduced between this setting and reset to count the number. do. This counted number is proportional to the above-mentioned phase difference, that is, the distance from the reference position to the stylus pen 5 within one period of the cosine line 9. Hereinafter, the distance corresponding to the counted number will be referred to as a PD value. This PD value N is shown in FIG. 2b.

18 is each terminal T ₀ to _{T 4} of the selector conductor 10...
The stylus pen 5 is sequentially switched (scanned) by the selector 11.
19 is a hold circuit that holds the output value of the amplifier 18, and 20 converts the output value held in the hold circuit 19 into a corresponding digital value. It is an A/D converter. A signal processing device 21 inputs signals from the counter 17 and the A/D converter 20 and calculates the coordinates of the stylus pen 5 on the tablet 7 based on these signals. That is, by the signal of the selector conductor 10, it is detected which comb teeth the stylus pen 5 is located between.
Further, since the position of the stylus pen 5 within one cycle of the cosine line 9 is known from the PD value obtained from the counter 17, the coordinates of the stylus pen 5 can be calculated from now on. Note that the signal processing device 21
also instructs the selector 11 to switch each terminal (including scanning of selector terminals).

By the way, in the above coordinate detection device, when the stylus pen 5 is placed almost perpendicular to the surface of the tablet 7, the output signal appears only between the corresponding comb teeth of the selector conductor 10, so there is no problem in detecting the coordinate area. . However, in general, when using the stylus pen 5, it is often tilted considerably with respect to the surface of the tablet 7, and in this case, the selector conductor 10 is not only located between the comb teeth where the stylus pen 5 is located, but also between the comb teeth. Signals are also generated between adjacent comb teeth, making accurate coordinate detection impossible. In order to avoid such a situation, conventionally, the coordinate area is detected by the selector conductor 10 using the method shown in FIG.
The following measures were adopted. That is, instead of sequentially scanning adjacent comb teeth of the selector conducting wire 10, this method skips one comb tooth and scans the other. As shown in Figure 2a, first, between terminals T ₁ and T ₃ , then between terminals T ₂ and T ₄ ,
Next, scanning is performed between terminals T ₃ and T ₅ , and so on. Hereinafter, the number between these terminals will be referred to as a mesh, and the number indicating the mesh number will be referred to as a mesh number. In Fig. 2a, the mesh number 0 (mesh No. 0) is between the terminals T ₁ and T ₃ , and the mesh number 1 (mesh No. 1) is between the terminals T ₂ and T ₄ .

FIG. 2c shows the detected voltage of each mesh of the selector conducting wire 10 when the stylus pen 5 is tilted. Now, for example, stylus pen 5 is tablet 7.
Suppose it is placed at point A above. In this case, in the selector conductor 10, the voltage is
V _a2 is the mesh number and voltage V _a1 is the mesh number.
A voltage V _a3 is generated at These voltages are input to a signal processing device 21 via a hold circuit 19 and an A/D converter 20, respectively. In the signal processing device 21,
The values of each voltage are compared and the order in which each value occurs is checked, in this case the intermediate value V _a2 ,
Since the values occur in the order of the large value V _a1 and the small value V _a3 , it is determined that the stylus pen 5 is at the middle mesh among the three meshes, that is, the mesh No. Then, assuming that the coordinate origin is on the vertical line passing through the terminal _T1 , the X of the stylus pen 5
For the axis coordinates, multiply the mesh number by 1/2 of the mesh pitch, and add the PD value Na in this case to the obtained number.
The sum of the values is X _A. Also, stylus pen 5
If is at point B, mesh No. 0, mesh No.
, the voltages V _b3 and V _b at mesh No., respectively.
₁ , V _b2 occur in order, and the order of their magnitude is small,
Since the values are large and medium, the signal processing device 21 determines that point B is at the last mesh, that is, mesh No., multiplies 2 by 1/2 of the mesh pitch, and adds the PD value Nb to that value. Obtain the X coordinate value X _B. From the above, in order to detect point A or point B, it is necessary to perform the detection procedure for the selector conducting wire 10 three times.
Also, at point C, it is necessary to perform the detection procedure twice.

In this way, in conventional coordinate area detection using selector conductors, there are cases where three voltages are detected, so when one voltage is detected, two detection processes must be performed afterwards. ,
As the number of detection processing circuits and judgment conditions increases, the number of coordinate area detection processes increases, and the magnitude relationship and occurrence of voltages when two voltages are detected and when three voltages are detected. This method has the disadvantage that coordinate area detection becomes extremely complicated because the determination must be made in order and the number of determination conditions increases.

SUMMARY OF THE INVENTION An object of the present invention is to provide a coordinate detection device that eliminates the above-mentioned drawbacks and can more easily detect a coordinate area.

To achieve this objective, the present invention provides cosine,
A selector conductor is placed every half cycle of the sine wire, and the output voltage of the selector conductor is compared with a certain set value in sequence, and when a voltage higher than this set voltage is generated, the number of times that voltage has occurred and Based on the position of the selector conductor at that time, the coordinate area of the selector conductor in which the excitation device such as a stylus pen exists is determined, and this determined coordinate area and the cos
The present invention is characterized in that the coordinates of the excitation device are calculated based on the position of the excitation device within one cycle of the line and the sin line.

The present invention will be explained below based on the embodiments shown in FIGS. 3 and 4.

FIG. 3 is a layout diagram of each conductive wire on a tablet of a coordinate detection device according to an embodiment of the present invention. In this embodiment, the arrangement of the cosine line 8 and the sine line 9 is the same as that of the conventional example shown in FIG. 2a. 22 is a selector lead wire. The selector conducting wire 22 is formed in a comb-teeth shape as in the conventional example, but whereas the selector conducting wire 10 in the conventional example has comb-teeth with a pitch equal to one period of the cosine wire 8 and the sine wire 9. The selector conducting wire 22 of this embodiment has comb teeth with a pitch equal to half the period of the cosine line 8 and the sine line 9. _T0 ～ _T5
are the terminals of each comb tooth, the number 0 mesh is between terminals T ₁ and T ₃ , the number mesh is between terminals T ₂ and T ₄ , and the number mesh is between terminals T ₃ and T ₅ . In this way, the pitch of the mesh is also the same as that of the conventional selector lead wire 10.
It becomes 1/2 of the pitch of.

FIG. 4 is a block diagram of a part of a coordinate detection device according to an embodiment of the present invention. In the figure, the same parts as those shown in FIG. 1 are given the same reference numerals. In addition,
In FIG. 1, the system from the oscillator 1 to the stylus pen 5, the tablet, and the signal processing system for the cosine and sine lines are not shown. This embodiment differs from the previous embodiment in that the amplifier 18
A comparator 23 is provided for comparing the amplified signal of the selector conductor 22 with a predetermined set voltage. The comparator 23 outputs a signal when a voltage higher than the set voltage is input, and the signal is held in the hold circuit 19, converted to a digital value by the A/D converter 20, and input to the signal processing device 21. Ru.

Next, the operation of this embodiment will be explained with reference to the conductor arrangement diagrams, PD values, and selector voltage waveform diagrams shown in FIGS. 5a to 5e.

FIG. 5a is a diagram showing the same arrangement as the cosine line 8, sine line 9, and selector line ₂₂ shown in FIG. )
The arrangement of each wire in the terminal T _o+3 part is shown. or,
FIG. 5b shows the PD values corresponding to FIG. 5a.
Now, if the stylus pen 5 is placed almost perpendicular to the surface of the tablet 7, there will be a gap between the terminal T _o-2 and the terminal T _o {the (n-3)th mesh}, ......, the terminal
Selector conductor 2 occurring between T _o+1 and terminal T _o+3
The voltage of 2 becomes the voltage shown in FIG. 5c. If the stylus pen 5 is tilted to the left, for example, the voltage between the terminals will be as shown in FIG. 5d, and if it is tilted to the right, the voltage will be as shown in FIG. 5e. Furthermore, it is assumed that the value of the set voltage in the comparator 23 is the voltage level _Vs shown in FIGS. 5c to 5e. In addition, in Figure 2,
Assuming that the origin of the coordinates is on the vertical line of terminal T ₁ ,
n in FIG. 5 is an odd numbered terminal. Also, in the following explanation, among the two terminals of each mesh,
The terminal with the smaller number closest to the origin is the selector terminal for that mesh. For example, terminal T _o-2 , T _o
The selector terminal of the (n-3)th mesh between them is terminal T _o-2 .

Here, the calculation of coordinates including the determination of the coordinate area in this embodiment will be described. The set voltage V _s is set at a level that allows the voltage on the selector conductor 22 to be avoided from being detected three times during scanning. Therefore, the number of detections is 1
or twice. First, when the voltage of the selector conductor 22 is detected once, (1) the selector terminal is an odd number, (2) the selector terminal is an even number, and the PD value is between 0 and less than 1/2 of the maximum value. (3) When the selector terminal is an even number and the PD value is 1/2 or more of the maximum value, determine the coordinate area in the above three parts,
Perform coordinate calculations. In the case of (1), the X-axis coordinate is calculated by adding the PD value to the distance from the origin to the selector terminal (the number obtained by subtracting 1 from the number of the selector terminal multiplied by the pitch of the selector conducting wire 22).
In case (2), add the PD value to the distance to the next selector terminal (terminal in the middle of the mesh). In the case of (3), the PD value is added to the distance to the selector terminal with the next lowest number.

Next, if the voltage of the selector conducting wire 22 is detected twice, the next determination is made only for the first detected mesh. (1′) The current PD value is between 0 and less than 1/2 of the maximum value, or (2′) The current PD
Is the value 1/2 or more of the maximum value? In the case of (1'), the coordinates are calculated by adding the PD value to the distance from the origin to the next selector terminal. In the case of (2'), the coordinates are calculated by adding the PD value to the distance to the selector terminal.

The calculation of the coordinates described above when the stylus pen 5 is placed at points D and E shown in FIG. 5A is as follows. First, when _the stylus pen 5 is placed vertically at point D, as shown in _FIG .
The selector voltage V _d1 is detected in mesh No. 2), and since this voltage V _d1 is larger than the set voltage V _s , the comparator 23 outputs a detection signal. In this case, detection is performed only in the relevant mesh.
This is a times detection. On the other hand, the count number of the counter 17 is input to the signal processing device 21 and the PD value is calculated, and the scanning of the selector terminal is performed by the command of the signal processing device 21, so the selector terminal in this case is the terminal It is known that it is T _o-1 . From these points, the number of detections is 1, the selector terminal is an even number, and the PD value is 1/2 or more of the maximum value, that is,
The signal processing device 21 determines that the condition (3) above is met. Therefore, the X-axis coordinate of point D is the distance from selector terminal T _o-1 to selector terminal T _o-2 , which is one number smaller than selector terminal T o-1 in this case, that is,
It is calculated by adding the PD value to the number obtained by multiplying (n-3) by the pitch of the selector conducting wire 22.

When the stylus is placed at point D with the stylus pen tilted to the left, as shown in _FIG . Therefore, the exact same judgments and calculations are performed to calculate the coordinates.

When the stylus pen 5 is placed at point D with it tilted to the right, the voltage at the (n-3)th mesh is
V _d3 , then the voltage V _d at the (n-2)th mesh
₄ is detected twice. Therefore, only the detection of the first (n-3) mesh is judged. In this case, the PD value is more than 1/2 of the maximum value, so the above condition (2') is met, and the (n-th)
3) The coordinates of point D are calculated in the same way as in the above case by adding the PD value to the distance to the selector terminal T _{o-2 of mesh number T o-2} .

Next, when the stylus pen 5 is placed vertically at point E, the terminals T _o-1 and T _o
The selector voltage V _e1 is detected at the (n-2)th mesh between ₊₁ and (n-2). In this case, the conditions are: the number of detections is 1, the selector terminal is an even number, and the PD value is 1/2 of the maximum value.
Since the number is smaller, condition (2) above is met. Therefore, the X-axis coordinate of point E is the distance between the selector terminal T o next to selector terminal T _{o -1} and the origin, that is, the pitch of the selector conductor 22 at (n-1). Calculated by adding the PD value to the multiplied number. When the stylus pen 5 is placed at point E with the stylus pen 5 tilted to the right, the voltage V _e4 will be detected once in the same mesh as shown in FIG. A calculation is made.

Point E with the stylus pen 5 tilted to the left.
, the (nth
−2) voltage V _e3 at the mesh
-1) The voltage V _e2 at the mesh is detected twice. Therefore, the first detection, the (n-th
2) Determine whether the number mesh is detected. In this case, the PD value is less than 1/2 of the maximum value, so the condition (1') above is met, and the distance between the next selector terminal T _o of this selector terminal T _o-1 and the origin By adding the PD value to , the coordinates of point E are calculated in the same manner as described above.

In this embodiment, the selector terminals are numbered sequentially from the origin, and scanning of the selector terminals is performed from the smallest terminal number to the largest terminal number.

In this way, in this embodiment, selector conductors are arranged every half cycle of the cosine line and the sine line, so that only the selector voltage higher than a certain set voltage is detected, and each of the one-time detection and two-time detection Since the calculation is performed based on the selector terminal number and PD value in the case of , the number of times the selector voltage is detected can be reduced to two, and the number of judgment conditions can also be reduced accordingly. This makes detection much easier and more accurate than coordinate detection using conventional devices. In addition, by increasing the pitch of the cosine and sine lines, the thickness of the tablet can be increased, eliminating the appearance of shadows from each conducting wire on the tablet surface in coordinate detection devices that project light from the rear. It is known that the conventional COS wire,
In a configuration in which a selector lead wire is arranged for each cycle of the sine line, the selector detection voltage decreases and it becomes difficult to perform the desired detection, but in this embodiment, a selector lead wire is arranged for each half cycle. Even if cos
Even if the pitch of the line or sine line is increased, the selector detection voltage does not drop, and accurate detection can be performed.

In the above-described embodiment, the output of the comparator 23 can also be directly input to the signal processing device as a binary signal of high level and low level. Further, in the above-mentioned condition determination, it is also possible to use the mesh number instead of the selector terminal number as the basis.

As described above, in the present invention, the selector conductors are arranged at intervals of half a cycle of the two conductors arranged on the board, and only the selector voltage higher than a certain set voltage is detected. Since the position of the excitation device such as a stylus pen is determined based on the position of the coordinate area and the PD value, the number of times the coordinate area is detected can be limited to two, making it possible to perform detection easily and accurately. It is also possible to prevent the selector detection voltage from decreasing.

[Brief explanation of drawings]

Fig. 1 is a block diagram of a conventional coordinate detection device, Fig. 2 a, b, and c are detection conductor wiring diagrams, PD value and selector detection voltage waveform diagrams of the device shown in Fig. 1, and Fig. 3 is a diagram of the present invention. FIG. 4 is a partial block diagram of the coordinate detecting device according to the embodiment of the present invention, and FIG. 5 a, b, c, d, and e are the third Detection conductor wiring diagram explaining the operation of the embodiment shown in Fig. 4 and Fig. 4, PD value,
FIG. 3 is a selector detection voltage waveform diagram. 5... Stylus pen, 7... Tablet, 8
...cos line, 9...sin line, 11...selector, 1
4... Adder, 16, 23... Comparator, 17...
Counter, 21...Signal processing device, 22...Selector conductor.

Claims (1)

[Claims] 1 an excitation device that is excited at a predetermined oscillation frequency;
Two conductive wires are arranged in a meandering manner on a substrate with a predetermined period and output a voltage according to the position of the excitation device, and the position of the excitation device within the period of the conductive wire is determined based on the voltage. In the coordinate detection device, the output voltage of each of the selector wires is sequentially compared with a predetermined set voltage, and the selector wires are arranged at intervals of 1/2 of the period of the conductor wires. A comparator that generates a signal when the output voltage is higher than the set voltage of the lever, the number of times the signal is generated from this comparator, the position of the selector line at that time, and the value obtained by the calculation means. and processing means for determining the coordinates of the excitation device based on the coordinates of the excitation device.