JPH04246714A - Coordinate detector - Google Patents

Abstract

PURPOSE:To constitute the detector so that an area can be decided even if a coordinate indicator indicates on a conductor of a first loop. CONSTITUTION:Width of a conductor 10 of a first loop is made larger than width of the other conductor 2, etc. In such a way, with respect to a magnetic field generated from a coordinate indicator, the conductor 10 comes to have the same effect as a state that many thin conductors are placed at a minute interval, and even if the coordinate indicator indicates on the conductor 10, many thin conductors which are not indicated come to exist, an induction voltage is generated on these conductors, and it can be used as a phase comparing signal for deciding an area.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detector equipped with an area determining device for determining whether the area at a position indicated by a coordinate indicator is a valid area or outside the valid area.

0002

2. Description of the Related Art A coordinate detector includes a tablet on which a conductive wire is laid in a predetermined form, a coordinate indicator that generates a magnetic field to generate a guidance signal on the conductor, and a coordinate detector that inputs the guidance signal and performs a predetermined process. It consists of an arithmetic processing section that obtains the coordinates of the position indicated by the coordinate indicator through arithmetic operations. Usually, the coordinate indicator in the above configuration is connected to the arithmetic processing section by a cord, but in recent years, cordless coordinate indicators have been proposed that omit the above cord for convenient handling. By the way, in the coordinate detector, when the coordinate indicator indicates the laying edge of the conductor or the position outside of it, the guidance signal is distorted, so the final coordinate values obtained are not reliable values. isn't it. That is, on the tablet, there is an area (valid area) in which the obtained coordinate values can be trusted, and coordinate values obtained in other areas are unreliable. Therefore, the coordinate detector requires a determining means for determining whether or not the position indicated by the coordinate indicator is a valid area. Such a determination means is proposed in Japanese Patent Application No. 2-188010. This will be explained with reference to FIG.

FIG. 3 is a diagram showing the arrangement of conductors of a conventional determining means of a coordinate detector using a cordless coordinate indicator. In the figure, A
indicates the above-mentioned effective area. Reference numeral 1 denotes a conductive wire disposed along and close to the outer edge of the effective area A, and numeral 2 denotes a conductor wire disposed along the outside of the conductor 1 at a distance therefrom. The conducting wire 1 forms a first loop, and the conducting wire 2 forms a second loop. B indicates a region between the first loop and the second loop, and C indicates a region outside the second loop. All of these areas and conductors are arranged on the tablet. T1
, T2 indicate terminals of conductors 1 and 2, respectively. In addition,
The illustration of the conductive wire laid in the effective area A and its terminal is omitted. When the coordinate indicator indicates a position within the effective area A and near the edge thereof, the induced voltage appearing at the terminal T1 and the induced voltage appearing at the terminal T2 have the same phase. However, when the coordinate indicator indicates the position of area B, the induced voltage appearing at terminal T1 and terminal T2
The phase is opposite to that of the induced voltage appearing in . In this way, by comparing the phases of the output voltages of the terminals T1 and T2, it is possible to determine whether the coordinate indicator is pointing to the effective area A or another area. Note that when the coordinate indicator indicates area C, the output voltages of terminals T1 and T2 will be in the same phase, but in this case, the induced voltage in the conductor laid in effective area A will be a minute value. , can be determined.

0004

[Problem to be Solved by the Invention] It is possible to determine whether or not the coordinate indicator indicates a position within the effective area A by the determination means using the first loop and the second loop. , if the coordinate indicator is located exactly above the conducting wire 1, this determination becomes impossible. This will be explained with reference to FIG. FIG. 4 is a waveform diagram of the induced voltage in the conducting wire 1. In the figure, the horizontal axis represents the position on the tablet in the direction of arrow E in Figure 3.
Moreover, the induced voltage output from the terminal T1 is plotted on the vertical axis. When the coordinate indicator indicates a position within the effective area A, the voltage induced in the conductor 1 is almost 0, but when the coordinate indicator indicates a position in an area other than the effective area A, the voltage induced in the conductor 1 The voltage induced in the conductive wire 1 has a value corresponding to the distance from the conductive wire 1. However, when the coordinate indicator is located directly above the conducting wire 1, the induced voltage becomes almost zero as shown in FIG. Therefore, in this case, it is no longer possible to compare the phases of the output voltages of the terminals T1 and T2, and it becomes impossible to determine the indicated position area of the coordinate indicator, resulting in a problem that coordinates cannot be detected. SUMMARY OF THE INVENTION An object of the present invention is to provide a coordinate detector capable of reliably determining an area by solving the problems in the prior art described above.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides a tablet on which a large number of conductive wires are laid in a predetermined form, a coordinate indicator having a built-in power source, an oscillation circuit, and a coil, and a coordinate indicator as described above. A coordinate detector comprising a processing section that detects coordinates by processing an induction signal induced in the conductive wire by a magnetic field generated from a coil, and the coordinate detector is installed surrounding and close to the outer edge of the coordinate detection effective area of the tablet. a first loop made of a conducting wire having a width sufficiently larger than the width of the conducting wire laid in the coordinate detection effective area;
A second loop consisting of a conductor laid outside and surrounding the first loop, and a phase of each induction signal generated in the first loop and the second loop by the magnetic field of the coordinate indicator. The present invention is characterized in that it includes an area determination device comprising phase comparison means for comparing.

[0006]

[Operation] Since the first loop conductor has a large width, the magnetic field generated from the coordinate indicator becomes equivalent to a state in which a large number of thin conductive wires are arranged at minute intervals. Therefore, even when the coordinate indicator points on the conductor of the first loop, an induced voltage sufficient for phase determination is generated in the conductor.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be explained below based on the illustrated embodiments. FIG. 1 is a diagram showing the arrangement of conductors of an area determination device according to an embodiment of the present invention. In the figure, the same parts as those shown in FIG. 3 are denoted by the same reference numerals, and the description thereof will be omitted. Reference numeral 10 indicates a conducting wire constituting the first loop, and T10 indicates a terminal of the conducting wire 10. While the conductor 1 of the device shown in FIG. 3 has the same width (0.3 mm) as the detection conductor of the effective area A and the conductor 2 of the second loop,
The conducting wire 10 of this embodiment has a width (1 mm) larger than the detection conducting wire of the effective area A and the conducting wire 2 of the second loop. Such a wide conducting wire has the same effect on the magnetic field generated by the coordinate indicator as a large number of thin conducting wires placed at minute intervals, and the coordinate indicator Even if a point near the center of the conductor 10 is specified, an induced voltage will be generated in other parts of the conductor 10 that are deviated from that part, and the induced voltage appearing at the terminal T10 will never be 0 or a value close to 0. This state is shown in FIG. Figure 2
1 is a waveform diagram of the induced voltage in the conducting wire 10. FIG. In the figure, the horizontal axis represents the position on the tablet in the direction of arrow F in FIG. 1, and the vertical axis represents the induced voltage output from terminal T10. Even if the coordinate indicator is located on the conductor 10, the induced voltage appearing at the terminal T10 has a value higher than a certain voltage VS due to the above-mentioned reason, and therefore it is possible to compare the phase with the induced voltage appearing at the terminal T2. . As described above, in this embodiment, the width of the conductive wire 10 is several times larger than the width of the other conductive wires, so even if the coordinate indicator points on the conductive wire 10, the width of the conductive wire 10 is
It is possible to generate an induced voltage without causing any problem in area determination. Although the coordinate indicator may indicate the complete center position of the conducting wire 10, this rarely occurs during actual coordinate detection operation, and even if it occurs, the coordinate indicator may indicate the perfect center position of the conductor 10. There are few cases where the center position is indicated, and if there is a slight inclination, an induced voltage will be generated, so there will be no problem in coordinate detection. Moreover, the width of the conducting wire 10 is 1
As an example, the value is several times that of other conductive wires (approximately three times as much in the above example), but the value is not limited to this, and can be set to an appropriate value in consideration of various conditions.

[0008]

As described above, in the present invention, the width of the first loop conducting wire is made sufficiently larger than the width of the other conducting wires, so that the coordinate indicator can point on the first loop conducting wire. too,
An induced voltage can be generated in the conductor, and this can therefore be used as a signal for phase comparison,
Area determination can be performed reliably.

[Brief explanation of the drawing]

FIG. 1 is a diagram showing a conductor arrangement of an area determination device according to an embodiment of the present invention.

FIG. 2 is a waveform diagram of induced voltage in the conductor shown in FIG. 1;

FIG. 3 is a diagram showing a conductor arrangement of a conventional area determination device.

FIG. 4 is a waveform diagram of induced voltage in the conductive wire shown in FIG. 3;

[Explanation of symbols]

2 Conductor wire 10 Conductor wire T2 terminal T10 terminal A Effective area B Area outside the effective area

Claims (1)

[Claims] 1. A tablet on which a large number of conductive wires are laid in a predetermined form, a coordinate indicator having a built-in power source, an oscillation circuit, and a coil, and processing of an induction signal induced in the conductive wire by a magnetic field generated from the coil. In a coordinate detector equipped with a processing unit that detects coordinates by using A first loop made of a conducting wire having a sufficiently large width, a second loop made of a conducting wire laid outside the first loop surrounding it, and a magnetic field of the coordinate indicator that causes the first loop to be and phase comparison means for comparing the phases of the respective guidance signals generated in the second loop.