JPS58123183A - Reading system of coordinate position - Google Patents

Abstract

PURPOSE:To simplify the constitution of a circuit, by setting the original point of a coordinate system and the reference points of X and Y axes at a coordinate input plate and then giving an arithmetic process to the information signal that shows the distances between the point indicated by a coordinate input pen and above-mentioned three reference points. CONSTITUTION:The coordinate original point 4 of a coordinate input plate 1 is set at the 1st reference point, and the 2nd and 3rd reference points 5 and 8 are set on the X and Y coordinate axes respectively. Then the 1st, 2nd and 3rd information signals are obtained to show the distances between a point P indicated by a light pen 3 and the reference points 4, 5 and 6 respectively. An arithmetic process is given to the 1st and 2nd information signals as well as to the 1st and 3rd information signals to detect the coordinate position of the point P.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinate position reading method suitable for reading characters and figures handwritten on a coordinate input board with a coordinate input pen.

In order to input handwritten characters and figures into a computer or display device, such characters and figures are written on a horizontal coordinate input board with a coordinate input pen, and the position of the coordinate input pen on the coordinate input board ( (hereinafter referred to as the indicated point) is x,
By converting the changes in the coordinate position of the indicated point, which changes from moment to moment, into electrical signals, characters and figures can be expressed as ym*.
It is supplied to electronic computers and display devices as a signal representing lt.

Such handwritten characters and figures can be read in real time, and characters and figures can be written quickly.

By the way, in the above method of reading characters and figures,
When writing characters and figures on the coordinate input board with a coordinate input pen, the position of the indicated point is generally determined by determining 12 reference points, and then the position of any point is determined by each of the two reference points and the arbitrary point. Since it is uniquely determined by the distance between the two reference points, two O reference points are set on the coordinate input board, and the coordinate position regarding these two reference points is expressed.

FIG. 1 is an explanatory diagram showing the principle of an example of such a conventional coordinate position reading system, in which 1 is a coordinate input board, 2
Fi alternating current source, 3 is a coordinate person wall/, 4.5 is a point electrode, and 6.7 is a current needle.

Next, the operation of this prior art will be explained.

In the figure, the coordinate input board 1 consists of a flat resistance plate,
Reference points B and C are set and each point electrode 4.5 is provided and connected to an ammeter 6.7.

Further, the coordinate input pen 3 is connected to the AC current source 2, and when the coordinate input pen 3 contacts the coordinate input board l, the AC current source 2
The alternating current flows through the coordinate input pen 3 and the coordinate input board l to the respective ammeters 6.7. The value of the current flowing through the ammeter 6.7 is inversely proportional to the distance between the point where the coordinate input pen 3 contacts the coordinate input board IK, that is, the indicated point P, and the reference points B and C.

By the way, now, the X-Y coordinate system is set on the coordinate input board 1, and the coordinate position of the reference point B is set at the origin of this X-Y coordinate system (0,
0) and set the coordinate position of reference point C to an arbitrary point on the X axis (x
@, 0), the indicated point P located at the coordinate position (x, y)
The distance #b from to reference point B is: b - x2 + y snow (1)
The distance C from the indicated point P to the reference point C is a” =
(x −X@)” + y snow
......(2), so the formula (
From 1) and (2), y=J ward=7...
...(4), and the coordinate position of the indicated point P is determined.

Therefore, as mentioned above, the current Ib flowing through the ammeter 6.7
, Eng. are inversely proportional to the distances and e, respectively, so b = k / 11) c = k / I 6 However, if k is a constant, then from equations (3) and (4), the reference point B, By arithmetic processing the current obtained from C, a signal representing the position coordinates of the indicated point P is obtained.

By the way, as is clear from equations (5) and (6), the calculation formula for determining the coordinate position (x, y) of one designated point P is the value X.

The difference is with respect to y, and the operations to obtain the value X consist of addition, subtraction, multiplication, and division, whereas the operations to obtain the value y consist of subtraction, multiplication, division, and square root. Separate and complex arithmetic circuits are not required. This means that, considering the circuit configuration, the value y can only be found by finding the value
Since subtraction and square rooting are performed, the error generated in the value X is multiplied by the value yK'lA, and the result of the calculation of the value y is less accurate than the result of the calculation of the value X.

As mentioned above, the conventional coordinate position reading method has a circuit configuration,
The purpose of the present invention is to eliminate the drawbacks of the prior art described above and to provide a system that can obtain the respective values x and y of the coordinate position of an indicated point using a common arithmetic circuit. The purpose is to provide a method for reading the coordinate position of Kl, 7 so that it can be converted into a coordinate position.

To achieve this objective, the present invention provides a coordinate input plate K,
Set reference points at the origin of the coordinate system and each of the X and Y axes,
Information signals representing the respective distances between the indicated point and these three reference points are obtained, and the information signals are processed in the same calculation format to obtain the x and y coordinate positions of the indicated point. Features.

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.0 Fig. 2 is an explanatory diagram showing the principle of the coordinate position reading method according to the present invention, in which 8 is a point electrode, 9 is a current needle,
Corresponding parts are given the same symbols.

Next, the operation shown in FIG. 2 will be explained.

In the figure, when the coordinate input pen 3 is brought into contact with the coordinate input board 1, a current flows from the indicated point P to the ammeter 9 as well as the ammeter 6.17, and this current value is measured at the indicated point P. As stated in item 11 of the explanation of the prior art, it is inversely proportional to the distance between and the reference point A.

By the way, let the coordinate position of the reference point B be (0,0), and the coordinate position of the reference point A
, the coordinate positions of C (Oe 7@L (x6+0)
If the coordinate position of the indicated point P is (x, y), then the respective distances between the indicated point P and the reference points B and C, cld, are as in equations (1) and (2) above, b −□ +y
......(ηc"-=(x yyo)” ...(9).

From equations (7) and (8), y==! (11)

From formulas (7) and (9), x-...JF72
...(12). Therefore, from the three information signals representing the distance aebect, the calculation formula representing each value 11F of the coordinate position of the indicated point P is 2.
By the way, if you look at equations (10) and (13), the calculation formats are exactly the same as To, so if you perform the calculation using these two equations, the values x and y will be It is possible to use the common 0 arithmetic Kamiro.

The current value obtained at point electrode 8.4.5 was calculated for 5 s. Then, azk/I.

b-ni/Ib @=ni/le From equations (1G) and (18), it may be true.

FIG. 3 is a block diagram showing an embodiment of the coordinate position reading method according to the present invention, in which 10 is a processing circuit, 11 is an arithmetic circuit, 12ti equivalent capacitance, 13.14° and 15 are resistors, respectively. 16.17.18 are respectively amplifier circuits, 19.20.2
1 is a resistor, 22.23゜24ij is a rectifier circuit, 2
5 is a switching circuit, 26.27 is a multiplication circuit, 28 is a subtraction circuit, 29 is a multiplication circuit, 30 is a division circuit, 31 is a multiplication circuit, 32 is an addition circuit, 33 is a division circuit, 34 is a constant circuit, 35 is an output Terminals and parts corresponding to those in FIG. 2 are given the same reference numerals.

Next, the operation of this embodiment will be explained.

In the same figure, when the coordinate input pen 3 is brought into contact with the coordinate input board 1, the contact points are the indicated point P and each reference point C.
, B, and A! . +l1)e■8 flows. The capacitance 12 is an equivalent capacitance generated between the coordinate input pen 3 and the coordinate input board l, and the resistors 13, 14.
15 are the respective resistances between the designated point P and the reference points C, B, and A.

The current Ic+ Ib II from each of the point electrodes 5.4.8 at the reference points C, B, and A is supplied to the processing circuit 10.
．． 20.21, from the regulator fILIl path 22, 23.24 and the switching circuit 2s9, from the current IcI, I
, are supplied to amplifier circuits 16, 17, and 18, respectively. Each amplifier circuit 141.17.18 has a resistor 19.20.21, respectively.
] Since the output signal is inverted and fed back to the input side, each point electrode 5, 4.8Fi of the coordinate input board 10 is grounded AC-wise. , Il) and I have current values inversely proportional to the resistance value of the resistor 13.14°15, respectively.

From the input side resistor 13, feedback resistor 19, and K of the amplifier circuit 160, a current of 1. Similarly, output voltages proportional to the current IbeIa are obtained from the output sides of the amplifier circuits 17 and 18, respectively.

These output voltages are rectified by rectifier circuits 22, 23, and 241, respectively, the voltages from the rectifier circuits 22, 24 are switched by a switching circuit 25, and the voltage from the rectifier circuit 23 is directly supplied to the arithmetic circuit 11. .

The arithmetic circuit 11 includes multiplication circuits 26 and 27, a subtraction circuit 28,
It consists of a multiplication circuit 29, a division circuit 30, a multiplication circuit 31, an addition circuit 32, a division circuit 33, and a constant circuit 34, and the multiplication circuits 26 and 27 have the function of squaring when the same two signals are input. O Therefore, now the voltage from the switching circuit 25 is Eα
, if the voltage from the rectifier circuit 23 is Eβ, then the multiplier circuit 2
The output voltage of 6.27 is also E respectively.

E2. These are the subtraction circuit 28 and the multiplication circuit 29'.
, and the output voltages El, g, respectively, are:
E, -E')X -E''/E, -E*a @Eshi.

These voltages are supplied to the divider circuit 30, and its output voltage E is as follows.

This voltage E is multiplied by a constant kl from a constant circuit 34 in a multiplier circuit 31, then added to a constant xi in an adder circuit 32, and further divided by a constant 2x in a divider circuit 33, resulting in a calculation. The output voltage E0 of the circuit 11 is as follows.

Therefore, the voltage Eβ supplied to the multiplication circuit 27 is always
is supplied from the rectifier circuit 23, Eβ=lb, and the switching circuit 25 is now connected to the rectifier circuit 22.
If it is closed to the side, Eα=Ec. The output voltage E of the arithmetic circuit at this time is E@(!
Then, it becomes .

On the other hand, when the switching circuit 2 is closed to the rectifier circuit 24 side, Eα=E in the same way.

Since Eβ=Eb, the arithmetic circuit 1112) output voltage E at this time
, to E6. Then, it becomes .

Here, the voltages E, Eb, and Ec are at the reference points A and B.

The currents obtained from point electrodes 8.4.5 respectively provided at C (FIG. 2) 1. ,Ib,I. Since it is proportional to, the reference points A and B
The distance y0 between them is equal to the distance x0 between the reference points C and B, and the constant x from the constant circuit 34.

By appropriately determining k, formulas (14) and (15
), the voltage Egle in equation (17) represents the value X of the indicated point PO sitting position X, 'I), and the voltage Eoa t'j value y of the equation (1B).

In addition, when the distances of the reference points A and C from the reference point B are made to be different, depending on the switching of the switching circuit 25,
As described above, the switching circuit 25 is switched from the constant circuit 34 to the addition path 32°. ! A signal is obtained alternately.

By the way, in the above embodiment, the case where a resistance plate was used as the coordinate input board was explained, but the invention is not limited to this.
For example, an elastic diaphragm may be used to obtain a coordinate signal, or a coordinate input pen may emit a sound wave to obtain a signal proportional to the propagation time of each reference point. By detecting the phase difference between the signal obtained from the point electrode and the reference signal, an information signal is obtained which fits the distance between the indicated point and each reference point.

As explained above, according to the original Wi4, the coordinate person
1 Force plate K, the origin of the coordinate system, each of the x and y axes, and KtA
By setting quasi-points and calculating the information signals representing the distances between the point indicated by the coordinate input pen and these three reference points, p1 each value of the coordinate position (z, y) of the indicated point is calculated. Since it is designed to obtain x + y, the value x
, y can be obtained by a common arithmetic circuit, and therefore,
11. The enclosure structure can be simplified, and the calculation accuracy can be made equal to each other, thereby providing a coordinate position reading method with excellent functions while eliminating the drawbacks of the above-mentioned prior art.

[Brief explanation of drawings]

Figure 111 is an explanatory diagram showing the principle of an example of the conventional coordinate position reading method, Figure 12 is an explanatory diagram showing the principle of the coordinate position reading method according to the present invention, and Figure 3 is an example of the coordinate position reading method according to the present invention. FIG. l...Coordinate input board, 3...Coordinate input pen, 4゜5.8...Point electrode, 11...
1 path of calculation.

Claims (1)

[Claims] (1) Based on an information signal representing the distance between a reference point set on a coordinate input board and a point indicated on the coordinate input board by a coordinate input pen, the coordinate position of the indicated point is obtained. In the coordinate position reading method, the coordinate origin of the coordinate input board is set as a first reference point, and second . A third reference point is set, and the designated point and the building 1. The first . obtaining second and third information signals, processing the first and second information signals, and processing the first and third information signals to obtain the coordinate position of the indicated point; A coordinate position reading method characterized by being configured so as to enable the following. (2. In claim (1), the first and second information signals are defined as: x: value b of the coordinate position of the indicated point in the X-axis direction; b: the tenth information signal C: The 20th information signal Value a of the coordinate position in the Y-axis direction: the third information signal y: performs arithmetic processing of the information signal representing the distance between the first and third reference points, and each of the above calculations is carried out in a common arithmetic circuit. The coordinate position reading method is characterized in that it is configured as follows: The plate is a flat resistance plate, and the first, second, and third information signals are inversely proportional to the respective distances MK between the pointing point and the first, second, and third reference points. A coordinate position reading system characterized in that the coordinate input plate is a signal.
A vibration wave is supplied from the indicated point by the coordinate input pen, and the first. Second and third information signals communicate with said pointing point and said first . A coordinate position reading system characterized in that the signal is proportional to the propagation time of the vibration wave propagating between the second and third reference points, respectively.