JPH06187085A - Coordinate reader - Google Patents

Abstract

PURPOSE:To transmit the switch information of a coordinate indicator to a tablet with high accuracy by turning a switching means on and superimposing the switch information on the amplitude of an alternating field while the alternating field is generated from the coordinate indicator. CONSTITUTION:When a cursor 2 is positioned on the read surface 6 of the tablet 4 and at least one of optional push button switches 18-21 is pushed, an alternating current from an oscillation circuit 24 is modulated to an amplitude pattern set by the pushed push button switches 18-21 at an amplitude modulation circuit 24 and is supplied to a pointer coil 3. Thus, the switch information which changes corresponding to the amplitude pattern is superimposed on the amplitude of the alternating field generated at the pointer coil 3. The alternating field is received by the respective sensing coils 7 and 8 of the tablet 4 and the electromotive force of sizes corresponding to respective distances from the pointer coil 3 is respectively induced. The electromotive force is amplified at an amplifier circuit 13 and amplitude demodulated at a demodulator 25, the amplitude pattern is decoded and the push button switch which was turned on is discriminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate reading device such as an electromagnetic induction type suitable for a wireless system in which a code for connecting a coordinate indicator to a tablet is omitted. The present invention relates to a coordinate reading device superimposed on an amplitude.

[0002]

2. Description of the Related Art Conventionally, as an example of this type of coordinate reading device, there is a wireless system in which a code for electrically connecting a coordinate indicator such as one or more cursors to a tablet is omitted. This is because the pointer coil of the coordinate indicator is excited by an alternating current of a predetermined frequency to generate an alternating magnetic field, and the alternating magnetic field causes the X and Y axes embedded in the X and Y axis directions of the coordinate reading surface of the tablet. By inducing an electromotive force in the sensing coil and measuring this electromotive force, the position of the coordinate indicator is detected by coordinates and given to a computer or the like.

The coordinate indicator has a switch for outputting switch information for instructing a computer or the like how to process the position data. The method for transmitting the switch information from the coordinate indicator to the tablet is as follows.
There is a method of transmitting the switch information by superimposing it on infrared rays or ultrasonic waves separately from the alternating magnetic field, and a frequency modulation method of appropriately modulating the frequency of the exciting current for exciting the pointer coil of the coordinate indicator.

[0004]

However, such a conventional infrared method or ultrasonic method has a problem of malfunction due to external noise.

Further, in the frequency modulation system, an expensive circuit element must be incorporated in the coordinate indicator in order to prevent malfunction due to changes in ambient temperature, and the tablet side has a frequency in order to prevent malfunction due to noise. This requires a plurality of expensive circuit elements such as bandpass filters and timing circuits, which complicates the circuit configuration and raises the cost.

Therefore, the present invention has been made in view of such circumstances, and an object thereof is to provide an inexpensive coordinate reading device which can easily and accurately transmit switch information of a coordinate indicator to a tablet. To do.

[0007]

The present invention is configured as follows in order to solve the above-mentioned problems.

The invention according to claim 1 of the present application (hereinafter, referred to as the first
Invention), the pointer coil of the coordinate indicator is excited by an alternating current to generate an alternating magnetic field, and the alternating magnetic field induces an electromotive force in the sensing coil embedded in the coordinate reading surface of the tablet. In a coordinate reading device that detects the position of the coordinate indicator by measuring the electric power, the switch means is turned on while an alternating magnetic field is being generated from the switch means and the pointer coil in the coordinate indicator. At this time, switch information output means for controlling the amplitude of the alternating magnetic field to output switch information for identifying the switch means that has been turned on is provided.

According to a second aspect of the present invention (hereinafter referred to as the second invention), the switch information output means is
It is characterized in that it is an amplitude modulation means for controlling the amplitude of the exciting current for exciting the pointer coil.

Further, the invention according to claim 3 of the present application (hereinafter referred to as the third invention) has a plurality of switch means, and the amplitude modulation means has a pointer corresponding to each of the plurality of switch means. It is characterized by having means for changing the amplitude of the exciting current of the coil.

Further, in the invention according to claim 4 of the present application (hereinafter referred to as the fourth invention), the amplitude modulating means modulates the amplitude of the exciting current of the pointer coil into at least two types per unit time. A plurality of combinations of patterns in which these amplitudes are variously arranged in time series are set in advance, and means for generating each of these patterns in correspondence with an ON operation of each switch means is provided.

The invention according to claim 5 of the present application (hereinafter referred to as the fifth invention) has a plurality of coordinate indicators,
Amplitude modulation means, the amplitude of the excitation current of the pointer coil,
A plurality of combinations of patterns, in which the amplitudes are modulated into two types per unit time and the amplitudes are variously arranged in time series, are set in advance, and each of these patterns is generated in correspondence with the ON operation of each coordinate indicator. It is characterized by having means.

Further, in the invention according to claim 6 of the present application (hereinafter referred to as the sixth invention), the amplitude modulating means modulates the exciting current of the pointer coil into at least two kinds of amplitude per unit time, and It is characterized in that the two kinds of amplitudes are variously combined in time series to form a plurality of patterns, and each pattern is generated in accordance with each switch means and each coordinate indicator.

Furthermore, the invention according to claim 7 of the present application (hereinafter referred to as the seventh invention) is to demodulate the amplitude of the electromotive force induced in the sensing coil when the tablet receives an alternating magnetic field. Thus, demodulation means for identifying the switch means that has been turned on is provided.

[0015]

[Action]

<First Invention> When the switch means is turned on while the alternating magnetic field is being generated from the coordinate indicator, the amplitude of the alternating magnetic field is controlled by the switch information output means, and the switch information is superimposed on the amplitude of the alternating magnetic field. To be done.

Therefore, the switch information can be detected by detecting the change in the amplitude of the alternating magnetic field.

That is, since the present invention superimposes the switch information on the alternating magnetic field, the malfunction is prevented by the external noise and the accuracy is improved as compared with the case where the switch information is superposed on the infrared rays and the ultrasonic waves as in the conventional example. In addition, unlike the frequency modulation method, there is no need to incorporate an expensive circuit element for preventing malfunction due to external noise, so that the configuration can be simplified and the cost can be reduced.

<Second Invention> When the switch means is turned on while the alternating magnetic field is being generated from the coordinate indicator, the amplitude of the exciting current for exciting the pointer coil of the coordinate indicator is modulated by the amplitude modulating means. The amplitude of the alternating magnetic field is controlled.

Therefore, since the switch information is transmitted to the tablet by amplitude-modulating the exciting current of the pointer coil, the malfunction due to the external noise is prevented and the accuracy is improved, as in the first aspect of the invention. Both simplification and cost reduction can be achieved.

<Third Invention> When the switch means is turned on while the alternating magnetic field is being generated from the coordinate indicator, the amplitude of the exciting current for exciting the pointer coil of the coordinate indicator is modulated by the amplitude modulating means. Moreover, the modulation is controlled to the amplitude corresponding to each of the plurality of switch means.

Therefore, the one which has been turned on can be identified from among the plurality of switch means depending on the amplitude of the exciting current of the pointer coil, and the switch information can be identified. Therefore, similarly to the first and second aspects of the invention, it is possible to prevent malfunction due to external noise, improve accuracy, and simplify the configuration and reduce cost.

<Inventions 4, 5, and 6> The amplitude modulating means is
The amplitude of the excitation current of the pointer coil is modulated into at least, for example, two types of low (L) and high (H) in a unit time, and further, these L and H are arranged in time series to form a plurality of patterns. .

Then, each of these patterns is assigned to each switch means, each coordinate indicator, or both.

Therefore, when any switch means, coordinate indicator, or both are turned on, an exciting current whose amplitude is modulated by a pattern assigned to the switch means, coordinate indicator, or both is generated. It is given to the pointer coil of the coordinate indicator.

For this reason, the amplitude of the alternating magnetic field of the pointer coil changes according to the pattern of the switch means that has been turned on, the coordinate indicator, or both, and is given to the tablet as switch information.

Therefore, according to the present invention, the amplitude of the alternating magnetic field is
It is possible to transmit switch information for identifying the switch means that has been turned on, the coordinate indicator, or both, to the tablet. That is, according to the present invention, since the switch information is transmitted to the tablet by amplitude modulation of the excitation current of the pointer coil, malfunctions due to external noise are prevented and accuracy is improved, and simplification of the configuration is achieved in the same manner as in each of the above inventions. The cost can be reduced together.

<Seventh Invention> The demodulating means of the tablet is
By demodulating the amplitude pattern of the electromotive force induced in the sensing coil, it is possible to identify the switch means that has been turned on, and by providing this to the computer or the like as switch information, the computer uses it as the switch information. The pointed position data of the coordinate pointing device is processed according to preset data processing.

That is, according to the present invention, the switch information can be received by demodulating the amplitude pattern of the electromotive force induced in the sensing coil of the tablet by the demodulating means.

[0029]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 2 is an overall configuration diagram of an embodiment of the present invention, and FIG. 3 is an enlarged view of a part of FIG.
The coordinate reading device 1 is a wireless electromagnetic induction type, and receives a cursor 2 which is an example of a coordinate indicator and an alternating magnetic field generated by a pointer coil 3 of the cursor 2,
It has a tablet 4 for detecting the designated position designated by the center point of the pointer coil 3 by coordinates.

The tablet 4 has an X-axis sensing coil 7 and a Y-axis sensing coil 8 in the X-axis and Y-axis directions, respectively, inside the coordinate reading surface 6 such as the upper surface of a body case 5 having a required shape. It is buried.

The X-axis and Y-axis sensing coils 7 and 8 are cursors 2.
Is to induce an electromotive force by electromagnetic induction in response to an alternating magnetic field from the pointer coil 3 of X.
The wires 9 are arranged side by side along the axial direction and the Y-axis direction, insulated in the vertical direction and made substantially orthogonal to each other. One ends of these conductors 9 are closed by the end conductors 9a and 9b, respectively, while the other open end is closed. , The X-axis multiplexer 10 and the Y-axis multiplexer 11 cause one end to the other end X1 of each X-axis and Y-axis.
.About.Xn and Y1 to Yn are sequentially or selectively closed to form adjacent conductors 9 in a loop-shaped coil.

The X-axis and Y-axis multiplexers 10 and 11 have an X / Y-axis switching circuit 1 for alternately switching their output terminals.
2, amplifier circuit 13, sample hold circuit 14, A / D
The converter 15 and the microprocessor 16 are sequentially connected, and the microprocessor 16 calculates the position of the electromotive force of the X-axis and Y-axis sensing coils 7 and 8 by the calculation method described in, for example, Japanese Patent Publication No. 3-61208. Then, the designated position designated by the cursor 2, that is, the center point of the pointer coil 3 is output in coordinates, and this is given to a computer or the like.

On the other hand, as shown in FIG. 1, the cursor 2 has a transparent window formed on the upper surface of the pointer coil 3 incorporated in the cursor case 17, and its center point is displayed by a cross-shaped mark or the like. On the upper surface of the case 17, a plurality of switch means, that is, first to fourth push button switches 1
8, 19, 20, and 21 are provided.

These first to fourth push button switches 18 to 2
1 outputs switch information for instructing a computer or the like how to process the pointed position data pointed by the pointer coil 3 when it is turned on, and is provided in the amplitude modulation circuit 22 as shown in FIG.

The amplitude modulation circuit 22 is interposed in the middle of an electric circuit that electrically connects an oscillation circuit 24, which uses a battery 23 as a power source, to the pointer coil 3, and the amplitude modulation circuit 22 is oscillated by the oscillation circuit 24 by an alternating current of a predetermined frequency. Exciting 3,
By controlling the amplitude pattern of this exciting current according to the ON operation of the first to fourth push button switches 18 to 21, the ON operation of the first to fourth push button switches 18 to 2 is performed.
The switch information for identifying 1 is transmitted to the tablet 5.

That is, as shown in FIG. 1 (A), the amplitude modulation circuit 22 sets the excitation current of the pointer coil 3 to the low level amplitude L per unit time and the high level amplitude H larger than this. Amplitude modulation is performed to each type of amplitude, and these amplitudes L and H are variously arranged in time series at a predetermined time t1 to t7, for example, as shown in FIG. The pushbutton switches 18 that have been turned on by being assigned to
Are formed as switch information for identifying each of .about.21, and when the push button switches 18 to 21 are turned on, an exciting current that repeats the amplitude pattern of the following Table 1 is applied to the pointer coil 3. This amplitude pattern corresponds to the timing chart shown in FIG.

[0038]

[Table 1]

Then, as shown in FIG. 2, a demodulator 25 for identifying the pushbutton switches 18 to 21 which are turned on by demodulating these amplitude patterns is connected to the output side of the amplifier circuit 13 of the tablet 5, The demodulator 25 supplies switch information to a computer or the like.
However, the demodulator 25 may be omitted by providing the microprocessor 16 with the demodulation function of the demodulator 25.

The microprocessor 16 detects the electromotive force induced in the sensing coils 7 and 8 when the amplitude pattern is at a low level amplitude L or at a high level amplitude H. In general, the electromotive force induced in the sensing coils 7 and 8 is large when the amplitude H is at a high level and is easy to detect. Therefore, it is better to detect when the amplitude H is at a high level. .

Next, the operation of this embodiment will be described.

When the pointer coil 3 of the cursor 2 is positioned on the reading surface 6 of the tablet 5 as shown in FIG. An alternating current having a predetermined frequency applied to the pointer coil 13 is modulated by the amplitude modulation circuit 24 into a predetermined amplitude pattern preset by the pushed push button switches 28 to 31, and the pointer coil 13 is energized.

For this reason, an alternating magnetic field is generated in the pointer coil 3, and the switch information that changes according to the amplitude pattern of the exciting coil of the pointer coil 3 is superimposed on the amplitude of this alternating magnetic field.

The alternating magnetic field is received by the X-axis and Y-axis sensing coils 17 and 18 of the tablet 14,
Since an electromotive force having a magnitude corresponding to each distance from the pointer coil 13 is induced in each of the coils 17 and 18, first, the X / Y-axis switching circuit 12 is set to, for example, the X-axis side in order to detect these. And the X-axis multiplexer 10 closes the open ends, for example, x1 and x2, of any two adjacent conducting wires 9, 9 on the X-axis side to form a loop-shaped coil and induce this coil. The generated electromotive force is amplified by the amplifier circuit 13, read by the sample hold circuit 14, further A / D converted, and then given to the microprocessor 16. By repeating this procedure, for example, the electromotive force in the X-axis direction is selectively detected at at least three points, and then the microprocessor 16 detects these detected values when the amplitude of the exciting current of the pointer coil 3 is low level L or high level H. It is read at any time, and the peak position of the electromotive force in the X-axis direction is calculated by the calculation method disclosed in Japanese Patent Publication No. 3-61208.

After that, the X / Y-axis switching circuit 22 is switched to the Y-axis direction, and then the electromotive force in the Y-axis direction is selectively detected at at least three points, which is determined in the same manner as in the case of the X-axis. The peak position in the Y-axis direction is calculated by the above calculation method and is given to a computer (not shown) as coordinate values thereof.

On the other hand, the demodulator 25 receives the electromotive force induced by the X-axis and Y-axis sensing coils 7 and 8 after being amplified by the amplifier circuit 13, demodulates the amplitude, and decodes the amplitude pattern.
Among the four push button switches 18 to 21, switch information for identifying the one that has been turned on is given to the computer or the like.

For this purpose, the computer sequentially receives these plural coordinate values and performs the processing according to the switch information.

Therefore, according to the present embodiment, the switch information for identifying which one of the first to fourth push button switches 18 to 21 has been turned on is superimposed on the amplitude of the alternating magnetic field, so that the switch information is transmitted by infrared rays or ultra light. It is possible to prevent malfunctions due to external noise as in the conventional example of superimposing on sound waves or the like and improve accuracy.

Further, unlike the conventional frequency modulation method, it is not necessary to incorporate an expensive circuit element for preventing malfunction due to external noise, so that both the simplification of the configuration and the cost reduction can be achieved.

In the above embodiment, the case where four switch means 18 to 21 are provided has been described, but the present invention is not limited to this, and, for example, a push button switch may be five.
You may provide one or more pieces and increase an amplitude pattern according to it.

Further, the coordinate indicator such as the cursor 2 and the input pen is not limited to a single one, but two or more coordinate indicators may be provided on the single tablet 5, and in that case,
An amplitude pattern for identifying the ON operation of the plurality of coordinate indicators may be provided similarly to the switch information.

[0052]

As described above, according to the first to seventh inventions of the present application, a switch that is turned on, a coordinate indicator, or a switch for identifying both of them depending on the amplitude of the alternating magnetic field output from the coordinate indicator. Since the information is superimposed, this switch information can be reliably transmitted to the tablet, malfunctions due to external noise can be prevented, accuracy can be improved, and expensive circuits such as the conventional frequency modulation method can be used. Since no element is used, both simplification of the configuration and cost reduction can be achieved.

[Brief description of drawings]

FIG. 1A is a waveform diagram showing both low-level amplitude and high-level amplitude, and FIG. 1B is a time-series arrangement of the amplitudes of these two levels in correspondence with the ON operation of a plurality of switches. 3 is a timing chart showing the combinations.

FIG. 2 is an overall configuration diagram of an embodiment of a coordinate reading device including the first to seventh inventions of the present application.

FIG. 3 is an enlarged view of a part shown in FIG.

FIG. 4 is a plan view of the cursor shown in FIG.

5 is an electric circuit diagram of the cursor shown in FIG.

[Explanation of symbols]

 1 Coordinate Reading Device 2 Cursor 3 Pointer Coil 4 Tablet 5 Body Case 6 Reading Surface 7 X Axis Sensing Coil 8 Y Axis Sensing Coil 9 Conductor 10 X Axis Multiplexer 11 Y Axis Multiplexer 12 XY Axis Switching Circuit 13 Amplifying Circuit 14 Sample Hold Circuit 15 A / D conversion circuit 16 Microprocessor 17 Cursor case 18 to 21 First to fourth push button switches 22 Amplitude modulation circuit 24 Oscillation circuit L Low level amplitude H High level amplitude

Claims (7)

[Claims] 1. A pointer coil of a coordinate indicator is excited by an alternating current to generate an alternating magnetic field, and the alternating magnetic field induces an electromotive force in a sensing coil embedded in a coordinate reading surface of a tablet. In the coordinate reading device for detecting the position of the coordinate indicator by measuring, when the switch means is turned on while the alternating magnetic field is being generated from the switch means and the pointer coil in the coordinate indicator. And a switch information output means for controlling the amplitude of the alternating magnetic field and outputting switch information for identifying the switch means that has been turned on. 2. The coordinate reading device according to claim 1, wherein the switch information output means is an amplitude modulation means for controlling the amplitude of the exciting current for exciting the pointer coil. 3. A plurality of switch means are provided, and the amplitude modulation means has means for changing the amplitude of the exciting current of the pointer coil in accordance with each of the plurality of switch means. The coordinate reading device described. 4. The amplitude modulating means modulates the amplitude of the exciting current of the pointer coil into at least two types per unit time, and sets a plurality of combinations of patterns in which these amplitudes are variously arranged in time series in advance. 4. The coordinate reading device according to claim 2, further comprising means for generating each pattern in response to an ON operation of each switch means. 5. A plurality of coordinate indicators are provided, and the amplitude modulation means modulates the amplitude of the exciting current of the pointer coil into two kinds of amplitude per unit time, and arranges these amplitudes in various time series. Set multiple combinations in advance,
5. The coordinate reading device according to claim 2, further comprising means for generating each of these patterns in correspondence with an ON operation of each coordinate indicator. 6. The amplitude modulation means modulates the exciting current of the pointer coil into at least two kinds of amplitude per unit time, and these two kinds of amplitudes are variously combined in time series to form a plurality of patterns. 6. The coordinate reading device according to claim 2, further comprising means for respectively generating each pattern in accordance with each switch means and each coordinate indicator. 7. The tablet is provided with demodulation means for identifying the switch means that has been turned on by demodulating the amplitude of the electromotive force induced in the sensing coil when receiving an alternating magnetic field. The coordinate reading device according to claim 1.