JPH06149449A - Digitizer - Google Patents

Abstract

PURPOSE:To reduce oscillation systems required for measurement as less as possible and to shorten measuring time by providing a conductor loop around a tablet, defining this conductor loop as a first oscillation element and composing the oscillation system of this first oscillation element and a loop coil arranged in an X axis direction. CONSTITUTION:When a position indicator 2 is positioned at any arbitrary position on a tablet 1, first of all, a loop coil x1 of an X axis scanner 11 is selectively connected by an address signal from a utilizing circuit 15. The circuit of the loop coil x1, a voltage amplifier 13x as second oscillation elements, a current amplifier 14 and a surrounding conductor loop 10 as third oscillation elements is formed. When the position indicator 2 as the fourth oscillation element gets close to this circuit, a stable oscillating state exceeding a prescribed level is provided. In a stage when this loop coil x1 is connected, a Y axis scanner 12 successively switches and connects loop coils arranged in a Y direction, and outputs are successively measured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention selects a desired pair of conductors (first and second oscillating elements) from a large number of conductors arranged on a tablet and connects them through a third oscillating element. However, the present invention relates to a digitizer of a system in which an oscillation system is constituted by these and a position indicator equipped with a fourth oscillation element.

[0002]

2. Description of the Related Art As a conventional device of this type, a digitizer of the following method previously proposed by the applicant of the present application (Japanese Patent Application No. 4-7
2421) was there. On the tablet of this digitizer, for example, a group of X-direction loop coils as conductors sequentially arranged in the X-direction (selected to become a first oscillation element).
And a Y-direction loop coil group (selected to serve as a second oscillating element) as conductors sequentially arranged in the Y-direction. In the X-direction loop coil group, any X-direction loop coil is selectively connected to the input side of the amplifier (third oscillating element) via the X-axis scanner, and the Y-direction loop coil group is connected via the Y-axis scanner. Either Y-direction loop coil is selectively connected to the output side of the amplifier.

Assuming that the position indicator is positioned on the surface of the tablet, the X-side loop coil (first position) arranged near the coil of the position indicator (fourth oscillating element).
Oscillator element) and the Y-side loop coil (second oscillation element) are connected to the input side and the output side of the amplifier (third oscillation element) via the X-side scanner and the Y-side scanner, respectively. A coil (fourth oscillating element) of the position indicator, an amplifier (third oscillating element), an X-side loop coil (first oscillating element) and a Y-side loop coil connected to the amplifier, triggered by noise radio waves or the like. The (second oscillating element) constitutes an oscillating system, and oscillates at a frequency peculiar to this oscillating system.
The output of the amplifier (third oscillating element) at this time is input to the utilization circuit and used for position determination. Such an oscillation system
The loop coil groups (that is, the first and second oscillating elements) are sequentially switched by the X-axis scanner and the Y-axis scanner to sequentially configure, and the output of the amplifier is sequentially measured and stored for each individual oscillation system. Go. In this way, since the oscillation output is stored and stored for each oscillation system, that is, along with the rank of each X-side and Y-side loop coil, the output distribution corresponding to the rank of each side loop coil can be obtained. The utilization circuit calculates and determines the position of the position indicator in the X and Y directions from the output distribution result.

[0004]

By the way, the above-mentioned device is of a system in which both the first oscillating element and the second oscillating element are sequentially selected from a plurality of conductor groups arranged in the tablet. While it is possible to minimize the number of conductors arranged in the above, it is necessary to sequentially switch each oscillation element to form a large number of oscillation systems one after another. Each oscillation system reaches stable oscillation after a short time, but it is still necessary to provide a waiting time before starting measurement, and these waiting times are accumulated in order to measure many oscillation systems. However, there is a drawback that the measurement time becomes long. The present invention has been made in order to improve this point, and provides a digitizer capable of shortening the measurement time by minimizing the oscillation system required for measurement.

[0005]

Therefore, according to the present invention, the first oscillating element and the second oscillating element provided on the tablet are provided.
And an oscillating element of No. 3 are connected by a third oscillating element, and an oscillating system is constituted by the combined body and the fourth oscillating element provided in the position indicator, and the oscillating system on the tablet is formed based on the output signal of the oscillating system. In the digitizer for detecting the pointing position of the position pointing device, the first oscillating element is constituted by a conductor loop arranged in a peripheral region of the tablet, and the second oscillating element is arranged in relation to the position of the tablet. The above-mentioned first
Oscillating element, selected second, third oscillating element and fourth
The oscillating system formed by the oscillating element is configured to detect the pointing position of the position pointing device on the tablet based on the output signal of the oscillating system when the oscillating system is in the oscillating state.

[0006]

The conductor loop is formed so as to surround the tablet, and this conductor loop is used as the first oscillating element. Further, loop coils are sequentially arranged in the X direction in relation to the position to form a second oscillating element, and the first oscillating element and the second oscillating element are coupled by the third oscillating element. The position indicator is provided with a fourth oscillating element, and when the position indicator is positioned on the tablet, the first to fourth oscillating elements constitute an oscillation system and a stable oscillation output can be obtained. . The X-direction position of the position indicated by the position indicator is determined based on this oscillation output. Further, apart from these oscillating elements, loop coils are sequentially arranged in relation to the position in the Y direction, and the voltage induced in these Y direction loop coils is measured when the above-mentioned oscillation system is formed. To do. Then, the position of the position indicator in the Y direction is determined from these voltage signals. Since the oscillation system requires only the number of X-direction loop coils, there is no large accumulation of waiting time for measurement.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings. 1 to 3 show a first embodiment of the present invention, respectively. FIG. 1 is a front view showing a conductor configuration on a tablet 1 and an electrical connection configuration relating to these, and FIG. 2 is a schematic diagram showing a position determining method. FIG. 3 is a schematic diagram schematically showing the output of each oscillating system constituted by each oscillating element of the present invention.

Please refer to FIG. A conductor loop 10 as a first oscillating element is provided in the peripheral portion of the tablet 1. Further, loop coils x1, x2, ..., Xn are sequentially arranged in the X direction of the tablet 1, and loop coils y1, y2 ,. Has been done. Each X-side loop coil group is configured as a second oscillation element, and the X-axis scanner 11
A desired loop coil is selected by, and the selected X-direction loop coil is connected to the conductor loop 10 which is the first oscillating element via the voltage amplifier 13x and the current amplifier 14. The output of the voltage amplifier 13x is the utilization circuit 1
5 and is used for position determination in the X direction.
Here, the voltage amplifier 13x and the current amplifier 14 act as a third oscillating element. Each Y-side loop coil group is provided for position determination in the Y direction, and the Y-axis scanner 1
A desired loop coil is selected by 2, and the voltage signal generated in this loop coil is taken into the utilization circuit 15 via the voltage amplifier 13y. The position indicator 2 has a fourth oscillating element including a coil 21, a first capacitor 221, and a second capacitor 222 connected by operating the switch 23.

Now, it is assumed that the position indicator 2 is positioned at an arbitrary position on the tablet 1. An address signal from the utilization circuit 15 first selectively connects the contact (loop coil x1) at the right end of the X-axis scanner 11. As a result, a circuit including the loop coil x1 (second oscillating element), the voltage amplifier 13x, the current amplifier 14 (third oscillating element), and the peripheral conductor loop 10 (first oscillating element) is formed.
When the position indicator 2 (fourth oscillating element) and these circuits are close to each other, the voltage amplifier 13 forming the third oscillating element
When the output of x exceeds a predetermined level, it is further amplified by the current amplifier 14 and this signal is supplied to the conductor loop 10 to bring about a stable oscillation state. In this case, when the position indicator 2 is present at a position apart from the selected loop coil x1, the output of the voltage amplifier 13x does not reach a predetermined level and a stable oscillation state is not achieved. Now, at the stage where the loop coil x1 is connected, the Y-axis scanner 12 sequentially switches and connects the loop coils arranged in the Y direction, and the utilization circuit 15 is connected via the voltage amplifier 13y.
To enter. Here, when the oscillation system formed at this time is continuously in an oscillating state, a predetermined magnetic field is generated from the fourth oscillating element of the position indicator 2, and this magnetic field causes the magnetic field to move in the Y direction. A predetermined voltage is induced in each loop coil. In this way, the X-axis loop coils are switched one after another to form oscillation systems of X-direction loop coils of different orders one after another, and the output of each oscillation system (voltage amplifier 13x) and each Y-direction loop coil (voltage amplifier) are formed. 13y) output is measured one after another.

With such a measurement operation, as shown in FIG. 2, an output voltage corresponding to the rank of the selected loop coil can be obtained in each direction. The utilization circuit 15 is
These output voltages are calculated using a predetermined calculation formula, and the coordinate value in each direction is determined.

Further, in the apparatus of this embodiment, the coil 21 of the position indicator 2 is provided with a capacitor 222 which is added according to the operation of the switch 23. By adding this capacitor 222, the oscillation frequency of the oscillation system formed at each measurement can be made different. Therefore, the on / off state of the switch 23 can be known by the use circuit 15 measuring the frequency of the output voltage at the time of position determination.

FIG. 3 is a plot of the output voltage of each oscillation system formed as described above. Here, FIG. 3A shows a method of measuring the output of each oscillation system. The fourth oscillating element of the position indicator 2 is positioned at a height h with respect to the loop coil surface of the tablet 1 and is positioned immediately above the X-direction loop coil that constitutes the oscillating system for each oscillating system, The output of amplifier 13x was measured. FIG. 3B is a plot of the measurement results. Space h between the position indicator 2 and the loop coil surface
Can be used in a wide range by making the size according to the size of the diameter of the loop coil. As described above, even when the first oscillating element is provided around the tablet 1, by providing a cover or the like on the loop coil surface of the tablet 1 to maintain the position indicator 2 at an appropriate height, It can be used in a wide range.

In this embodiment, the LC resonance circuit is used as the fourth oscillating element of the position indicator, but a magnetic substance or a conductor block may be used. Further, as the third oscillating element, a so-called negative resistance whose voltage-current characteristic becomes non-resistive may be used instead of the amplifier.

[0015]

As described above, according to the present invention, a conductor loop is provided around the tablet, the conductor loop is used as the first oscillating element, and the loop coil is arranged in the X-axis direction with the first oscillating element. Since the oscillating system is constituted by and, the oscillating system for measurement can be relatively reduced, and therefore the total measuring time can be shortened.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a tablet relating to a first embodiment device of the present invention.

FIG. 2 is a schematic diagram for explaining a calculation for position determination of the device of FIG.

FIG. 3 is an oscillation output diagram of the oscillation system of the present invention.

[Explanation of symbols]

 1: Tablet 2: Position indicator

Claims (1)

[Claims] 1. A first oscillating element and a second oscillating element arranged on a tablet are coupled by a third oscillating element, and a fourth oscillating element provided on the combined body and a position indicator. In the digitizer that configures the oscillation system and detects the pointing position of the position pointing device on the tablet based on the output signal of the oscillation system, the first oscillating element is formed by a conductor loop arranged in the peripheral region of the tablet. The second oscillating element is constituted by a plurality of conductor loops arranged in association with the position of the tablet and is selectable, and the first oscillating element, the selected second and third A digitizer characterized by detecting a pointing position of a position pointing device on a tablet based on an output signal of the oscillating system formed by the oscillating element and the fourth oscillating element when the oscillating system is in an oscillating state.