JPH02133815A - Input device for plane position coordinates - Google Patents

Abstract

PURPOSE:To attain the simultaneous input of positional coordinates of plural points by supplying the AC currents of plural types of frequencies to the driving lines in a time divisional switching way, and using a cursor which is synchronous with one of those frequencies. CONSTITUTION:The synchronous frequencies of 1st and 2nd cursor coils 31 and 32 are referred to as f1 and f2, respectively. A time domain is divided into two parts and a current of the frequency f1 is supplied to the first half of the same group of driving lines 1 together with a current of the frequency f2 supplied to the second half of the group 1, respectively. A process circuit 6 knows a specific signal that is inputted to a specific time phase, and therefore can calculate the center position between both cursors 31 and 32. Thus it is possible to attain the simultaneous input of the position coordinates of plural points on a digitizer tablet 10.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a plane position coordinate input device, and in particular to a so-called cordless tablet, which does not require a signal line code for a cursor for inputting position coordinates. The present invention relates to a plane position coordinate input device.

[Prior Art] As a prior art to the present invention, there is Japanese Patent Application No. 199668-1988 "Cordless Tablet" (hereinafter referred to as "Hikari Application") filed by the applicant on August 10, 1988.

FIG. 3 is a block diagram corresponding to FIG. 1 of the earlier application, in which (1) is a drive line group, (2) is a drive circuit, (
3) is a cursor coil, (4) is a sense line group, (5) is a sense circuit, and (6) is a processing circuit. Drive line group (1)
and the sense line group (4) are arranged in directions perpendicular to each other,
Therefore, the electromagnetic coupling between them can be considered to be flat in practice. If the direction of each drive line in drive line group (1) is
An orthogonal coordinate axis is assumed in which the axial direction and the direction of each sense line of the sense line group are the Y axis. - drive lines are composed of a pair of conducting wires parallel to the X-axis, a predetermined number of drive lines are arranged at a predetermined pitch in the Y-axis direction to form a drive line group (1), - sense lines is composed of a pair of conductors parallel to the Y-axis, and a predetermined number of sense lines are arranged at a predetermined pitch in the X-axis direction to form a sense line group (4), but the drawing is simplified in Figure 3. In order to Only three sense lines are shown: (j), the (j+1)th sense line, and Y(j-1), Y(j), and Y(j+1).

The cursor coil (3) is a coil attached to the cursor, but the cursor part is omitted in the drawing. The cursor coil (3) is a circular coil and is coupled to both the drive line and the sense line. The voltage induced in the cursor coil (3) by the alternating current flowing through the drive line causes an alternating current to flow through the cursor coil itself, and this alternating current induces a voltage in the sense line.

FIG. 4 is a block diagram showing the internal connections of the sense circuit (5) in FIG. ) is scanned by the switch (52). (53) is an amplifier, (5
4) is a detector, and (55) is an A/D converter.

FIG. 5 is an operation time chart showing an example of scanning of the drive line group (1) and the sense line group (4), in which a sequential current is supplied to each drive line. Assuming that the number of drive lines is n, one frame of scanning starts from the first drive line X(1), reaches the nth drive line X(n), and then scans x( The next frame is scanned from 1).
Figure 5 shows the period from t (i-1) to t (i+2) during which three drive lines X(i-1), X(i), and X(i+1) are scanned. The vertical axis of a certain 0 diagram shows the amplitude of the alternating voltage; for example, for X(i), t(i) to t
This indicates that an AC voltage of a predetermined amplitude is applied for a period of (i+1).

The scanning switch (52) shown in FIG.
1) will be changed. When the cursor coil (3) is located at the position shown in Figure 3, the amplifier (53) is connected to the amplifier (53) in the frame where the sense line Y (j-1) is connected to the amplifier (53).
3) The amplitude of the output AC voltage is shown as Y(j-1) in FIG. That is, during the period when current is flowing in the drive line (When a current flows through i>, the current induced in the cursor coil (3) increases, and therefore the voltage induced in the sense line Y(j-1) also increases.
The amplitude of the output of 53) is detected by a wave detector (54), and the value of this amplitude is converted into a digital value by an A/D converter (55), which is input to a processing circuit (6) and stored.

Next, the scan switch (52) connects the sense line Y(j) to the amplifier (53), and the drive circuit (2) connects the drive line group (1
) is scanned for one frame, and as a result, Y(j) is shown in Figure 5.
This results in a decile value of the voltage amplitude shown as being stored in the processing circuit (6).

From the digital values stored in the processing circuit (6) in this way, the positional coordinates of the center position of the cursor coil (3) on the tablet (10) can be calculated.

For example, if Y shown in FIG. 5 is equal, the center point position J of the cursor coil (3) 2 should match the center point of the intersection area of the drive line X(i) and the sense line Y(+). It is clear that, based on the same principle, Y(+-1) in each time domain between t(i-1) and t(i+2) in FIG.

J J Y (+), Cursor coil (3) from Y (main +1) value
The center position of can be calculated precisely.

By the way, the alternating current flowing through the drive line (1) can be switched between alternating currents having a plurality of different frequencies in a time division manner. In the previous application, the tuning frequency of the cursor coil was switched to be tuned to one of the plurality of frequencies, and the attribute of the input position coordinates was expressed by that frequency.

[Problems to be Solved by the Invention] As described above, the device of the earlier application was configured to switch the tuning frequency of one cursor coil, but it is not possible to operate multiple cursor coils simultaneously on the same tablet. It didn't have a proper structure. However, for example, in applications such as a "graphic input device" filed separately by the applicant of this application, a problem arises in which two cursor coils are desired to operate simultaneously on the same tablet.

This invention was made in order to solve the above-mentioned problems in the conventional ones, and it is possible to simultaneously operate multiple cursor coils on the same tablet and input the position coordinates of multiple points at the same time. The purpose is to provide a coordinate input device.

[Means for Solving the Problems] In this invention, as in the previous application, the alternating current flowing through the drive line is made to flow by sequentially switching alternating currents of multiple types of frequencies in a time-sharing manner, so that the alternating current is passed through the drive line at different positions on the tablet. The tuning frequencies of the placed cursors are different from each other, and the cursors are tuned to one of the plurality of frequencies.

[Operation] It is possible to distinguish which cursor the data comes from depending on the time phase of the signal input.

[Examples] Examples of the present invention will be described below with reference to the drawings. 1st
The figure is an explanatory diagram showing one embodiment of the present invention, and in the figure (
10) is a tablet similar to the tablet in Figure 4, (3
1) is a first cursor coil, and (32) is a second cursor coil. The tuning frequency of the first cursor coil (31) is fl, and the tuning frequency of the second cursor coil (32) is f2.

Figure 2 shows the drive line group (1) when the frequency of the alternating current supplied to the drive line group (1) (see Figure 3) is switched in time division.
) and the sense line group (4). In the time division example shown in FIG. 2, from t(i-1) to t(
The time domain from i), t (i) to t (i+1) is divided into two, and a current with a frequency f1 is passed through the same drive line in the first half, and a current with a frequency f2 is passed in the second half. Therefore, the first cursor (31) tuned to the frequency f1 is set to the drive line
i) and the sense line Y(j), the amplitude of the voltage induced on the sense lines Y(j-1), Y(j), and Y(j+1> is shown in Figure 2 (31). It changes like this.

If the second cursor (32〉) tuned to 2 in frequency is located in the intersection area of the drive line X(i) and the sense line Y(k), the sense lines Y(k-1), Y(k), Y(k+
The amplitude of the voltage induced in 1) changes as shown in FIG. 2 (32). The second cursor (32) is the drive line x (h)
and the sense line Y(k), the frequency f2 is applied to the drive lines X(h-1), X(h), and X(h+1).
During the time when the current is supplied, a voltage with an amplitude as shown in Figure 2 (32) is induced in the sense line.

Since the processing circuit (6) (see Figure 3) knows what kind of signal is input at which time phase, the first cursor (31) and the second cursor (32)
The center position of the cursor coil can be calculated.

The embodiment shown in Fig. 1 uses two cursors, but alternating currents of arbitrary multiple types of frequencies are passed through the drive line by time division switching, and tuned to one of the multiple types of frequencies. By using the cursor, you can input the position coordinates of multiple arbitrary points at the same time.

In addition, in the time division shown in FIG. 2, from t(i-1) to t (
Although time division is performed within the time slot as in i), it is also possible to use time division in which a current of the same frequency is passed without time division in the time slot, and the frequency is changed in synchronization with the change of the frame.

[Effects of the Invention] As described above, according to the present invention, the position coordinates of a plurality of points on the digitizer tablet can be input at the same time.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram showing an embodiment of the present invention, Fig. 2 is an operation time diagram explaining the invention in detail, Fig. 3 is a block diagram showing a conventional device, and Fig. 4 is the same as Fig. 3. FIG. 5 is a block diagram showing the internal connections of the sense circuit, and FIG. 5 is an operation time diagram showing the operation of the device of FIG. 3. DESCRIPTION OF SYMBOLS 1... Drive line group, 2... Drive circuit, 3... Cursor coil, 31... First cursor, 32... Second cursor, 4... Sense line group, 5...・Sense circuit,
6...processing circuit. Note that the same reference numerals in the figures indicate the same or corresponding parts. 4th II 稟TA cause

Claims (1)

[Claims] When the orthogonal coordinate axes on a plane are the X-axis and the Y-axis, a drive line configured to flow an alternating current through a pair of conductors parallel to the X-axis direction has a predetermined pitch in the Y-axis direction. A group of drive lines arranged in a predetermined number and a sense line configured to output an AC voltage induced in a pair of conductors parallel to the Y-axis direction are
A tablet having a sense wire group arranged in a predetermined number at a predetermined pitch in the axial direction, and a cursor having a cursor coil that can be placed at any position on the tablet, each driving the drive line group. While scanning the line so that the alternating current is passed through the line sequentially, the alternating voltage induced in the cursor coil due to electromagnetic coupling with this alternating current causes an alternating current to flow through the cursor coil, and the alternating current flowing through the cursor coil causes the alternating current to flow through the cursor coil. In a plane position coordinate input device that determines the positional coordinates of the center position of the cursor coil with respect to the XY coordinate axes by measuring the amplitude of voltage induced in each sense line of the sense line group, It is equipped with a frequency switching means that sequentially switches and flows alternating current of different frequencies in a time division manner, and a plurality of cursors placed at different positions on the tablet, each cursor of the plurality of cursors is A planar position coordinate input device comprising a tuning circuit that tunes to any one of the plurality of frequencies at mutually different frequencies.