JPS5924388A - Coordinate reader - Google Patents

Abstract

PURPOSE:To read assuredly the coordinates through a simple constitution, by providing a tablet containing loop coils distributed equidistantly and a cursor storing a conduction coil and then reading the coordinates of the cursor with the induced electromotive force of the loop coil. CONSTITUTION:A rectangular tablet 1 contains (n) units of loop coils arranged equidisitantly and with overlap with each other. Each loop coil is connected to the input terminal of an A/D converter 4 via analog switches 31-3n respectively. An oscillating pulse is applied to a coil 6 stored in a cursor 5 from a pulse oscillator 7. The output of a converter 4 is supplied to a microcomputer 8. The computer 8 delivers a switch control signal S to the switches 31-3n respectively and at the same time the timing signal T to the oscillator 7. Then the position of the coil 6, i.e., the cursor 5 is read from the electromotive force of all loop coils.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coordinate reading device that uses a loop coil to read coordinates.

Various coordinate reading devices have been proposed in the past, but they have problems such as being difficult to use, complicated, and expensive. Therefore, there is a need for a coordinate reading device that can reliably read coordinates and can be manufactured at low cost.

This invention satisfies the above-mentioned needs, and its purpose is to ensure that when an alternating current is passed through one of two different coils, an alternating current or force is generated in the other due to the action of electromagnetic induction. By using the Ichihara as the cursor and the electromotive force generator as the tufflet,
To provide a coordinate reading device that can reliably read coordinates and is inexpensive.

The present invention will be described below based on embodiments shown in the accompanying drawings.

As shown in FIGS. 1 and 2, the rectangular tablet 1 is provided with n loop coils 21, 22, . Each loop coil 21, 22, 2n is connected to an input terminal of the AD converter 4 via an analog switch 31, 32, . . . 3n, respectively. Further, the coil 6 housed in the cursor 5 receives five oscillation pulses from the pulse oscillator 7.

”=Note A-7) The output signal of the converter 4 is input to the microcomputer 8. This microcomputer 8 has the analog switches 31, 321...3.
n is turned on one by one in order to output a switch control signal S that connects the turned-on loop coil and the A-D converter 4 to the analog switches 31, 32, etc., and also outputs this switch control signal A timing signal T whose timing is aligned with S is outputted to the pulse oscillator 7. Also,
The microcomputer 8 has loop coils 21, 22,
... are sequentially connected to the /l-D converter 4, the coil 6
The electromotive force induced in the loop coils 2+, 22, . . . is stored in a storage unit (not shown).

The position of the coil 6, that is, the cursor 5, can be read by the electromotive force applied to all the loop coils 2+, 22, . That is, the electromotive force in the loop coil 2 is maximum,
If the electromotive forces of -1 and +1 in the loop coil 2 are equal, the position of the loop coil 2 becomes the position of the cursor 5, and the position Xk of the loop coil 2 from the origin can be read from the microcomputer 8. Also, if the electromotive force of +1 is equal to loop coil 2 and 2, the position of cursor 5 is +(Xk+
xkII). Furthermore, the electromotive force on loop coil 2 is maximum, and the electromotive force on loop coil 2 is +1.
Assuming that the electromotive force of the loop coil changes linearly with the largest ratio of 1:a, the position of cursor 5 is xk→-AT-(xkII-xk)=144 (xk
10aXI10, ). Note that this calculation is performed within the microcomputer 8, and the microcomputer only outputs the position of the cursor 5.

Incidentally, the timing signal 'I' from the microcomputer 8 is sent to the loop coils 21 and 22 by the coil 6.
This is to turn on the analog switches 31, 32, . . . when the electromotive force induced in .

Moreover, instead of recording all the electromotive forces for all the loop coils 21, 22, etc., the microcomputer 8 stores the coordinates even if it stores large electromotive forces and the corresponding loop coils. Can be read.

In the second embodiment, the loop coils provided on the tablet 1 do not need to overlap, as shown in FIG. 3, and the loop coils 2+ are arranged at equal intervals so as not to overlap. 22...maybe.

Moreover, in order to measure the plane coordinates consisting of the X direction and the y direction, it is sufficient to prepare two tablets 1 and overlap them so that the loop coils of each tablet are orthogonal.

As described above, the present invention includes a tablet in which loop coils are arranged at equal intervals and a cursor that houses the coil to be energized, and the coordinates of the cursor are read by the electromotive force of the loop coil induced by the coil. This has the advantage that the configuration is simple, the coordinates can be read reliably, and the tablet and cursor can be manufactured at low cost.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing an example of the present invention, FIG. 2 is a plan view showing the tablet of FIG. 1, and FIG. 3 is a plan view showing the other side of FIG. 1...Tablet, 2+, 22...Loop coil, 3+ +32...Analog switch, 4...
A-D converter, 5... Cursor, 6... Coil, 7
...Pulse oscillator, 8...Microcomputer.

Claims (1)

[Claims] A tablet with multiple loop coils arranged at equal intervals,
1. A coordinate reading device comprising: a cursor housing a coil to be energized, and reading coordinates by detecting an electromotive force induced in a loop coil of a tablet by the coil of the cursor.