JP3069706B2 - Coordinate reading device and its height information calculation method - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate reading device for inputting coordinates to an external device such as a computer, and more particularly to a reading device capable of calculating height information in addition to coordinate values. It relates to a method for calculating height information.

SUMMARY OF THE INVENTION The present invention relates to a coordinate reading apparatus for obtaining a coordinate value from a guidance signal guided to a sense line by electromagnetic coupling between the two when a coordinate indicator for generating an AC magnetic field is placed on the sense line. An object of the present invention is to realize a coordinate reading device that can also detect height information of a position where an indicator is placed. For this reason, in the present invention, in a control device that controls each part of the coordinate reading device and calculates a coordinate value at the same time, the coordinate information is calculated based on the guidance signal, and the position of the coordinate indicator and the specific positional relationship are calculated. Is extracted as a height detection signal, and height information is calculated based on this signal and the coordinate information.

[Prior Art] A technique for obtaining height information by using the amplitude of an induced signal is a known technique. FIG. 8 is an explanatory diagram thereof.

An excitation line 102 and a sense line 103 are arranged perpendicularly to form a sense line plate 101, an AC signal is applied to the excitation line 102, and an induced signal induced on the sense line 103 is observed. The coordinate indicator 104 includes a resonance circuit including a coil 105 and a capacitor.

When the coordinate indicator 104 is placed on the sense line plate 101 as shown in the figure, an induction signal is generated on the sense line 103 by the electromagnetic coupling of the excitation line 102, the coil 105, and the sense line 103. If the coordinate indicator 104 is directly above the sense line plate 101, the amplitude of the induction signal increases, and the sense line plate
The amplitude decreases as the distance from 101 decreases. If the induction signal is amplified and detected and the amplitude is measured, the height information of the coordinate indicator can be obtained.

[Problems to be Solved by the Invention] The above description describes the principle. Actually, a plurality of excitation lines 102 and a plurality of sense lines 103 are provided as a sense line plate 101, and a coordinate indicator 104 is provided as a sense line. The plate 101 is placed at an arbitrary position on the plane. It is not placed at a fixed point as shown in FIG.

For this reason, in the technique using the amplitude of the guidance signal as the height information, the amplitude changes depending on the position on the plane where the coordinate indicator is placed, and the height information cannot be detected accurately. there were.

For example, on the straight line x shown in FIG.
As shown in FIG. 9, the amplitude of the induction signal becomes maximum at the center of the sense line 103 and decreases as it moves to the periphery as shown in FIG.

The present invention has been made to solve the above problems in the conventional technology. The main purpose is to realize a coordinate reading device that can also detect height information of the position where the coordinate indicator is placed, and a more specific purpose is to have a high accuracy without being affected by the position. It is an object of the present invention to realize a coordinate reading device capable of detecting information.

[Means for Solving the Problems] In order to solve the above problems, in the present invention, a coordinate indicator for designating a coordinate reading point, and a sense line group for generating an induction signal based on the combination with the coordinate indicator A scanning circuit that connects the sense lines and selectively scans the same; an amplification detection circuit that is connected to the scanning circuit and detects an amplitude signal of the induction signal; A control circuit for calculating a coordinate value of a position where the indicator is placed,
Applying a selection signal to the scanning circuit to select the sense line group, inputting an amplitude signal of the induction signal, calculating coordinate information based on the input amplitude signal, From among the processing of extracting the amplitude signal of the guidance signal guided to the sense line in a specific positional relationship with the position of the coordinate indicator as a height detection signal, the height detection signal and the coordinate information A process of calculating height information of a position where the coordinate indicator is placed,
And the point provided.

A feature of the coordinate reading device according to the present invention resides in that the coordinate reading device is configured to execute processing based on the height information calculation method.

In these coordinate reading devices or the height information calculating method, the coordinate pointing device, the coordinate pointing device, and the sense line group are coupled based on electrical guidance, and the sense line group is coupled to the electrical guidance. The present invention can be applied to a system in which a guidance signal is generated in a sense line group by performing a coupling based on the coordinate line. The present invention can be applied to a coordinate reading device that generates a signal.

[Operation] In the coordinate reading device configured as described above, in the process of sequentially selecting the sense line group, if the coordinate indicator is placed near the selected sense line, the connection with the coordinate indicator is made. As a result, an induction signal is generated on the sense line. The control circuit calculates the coordinate information by comparing the amplitudes of the plurality of guidance signals.

On the other hand, if attention is paid to the amplitude of the guidance signal, which is guided to a sense line having a specific positional relationship with the coordinate indicator, of the guidance signal, this varies depending on the position and height of the coordinate indicator. The control circuit produces height information based on the signal and the coordinate information.

[Embodiment] (Configuration of a coordinate reading apparatus according to a first embodiment) Hereinafter, a first embodiment of the present invention will be described with reference to Figs. 1 to 4. In the first embodiment, the present invention is applied to a wireless coordinate reading apparatus that does not require a signal line to connect between the coordinate reading apparatus main body and the coordinate indicator.

First, the configuration will be described. FIG. 1 shows a configuration diagram of a coordinate reading device according to the present invention.

In FIG. 1, reference numeral 1 denotes a sense line plate on which an excitation line group 2 and a sense line group 3 are laid. The excitation line group 2 and the sense line group 3 form a folded loop,
They are arranged at equal intervals.

Reference numeral 4 denotes an excitation scanning circuit to which each excitation line of the excitation line group 2 is connected. The excitation scanning circuit 4 is composed of a plurality of electronic switch elements such as analog switches, and supplies an excitation signal ds supplied from an excitation circuit 6 described later to one selected excitation line.

Reference numeral 5 denotes a sense scanning circuit to which each sense line of the sense line group 3 is connected. Like the excitation scanning circuit 4, it is constituted by an electronic switch element, and one of the sense lines is selected and connected to an amplification detection circuit 7 described later.

6 is an excitation circuit. An excitation clock dc is input from a control circuit 8, which will be described later, and the waveform is shaped and amplified to generate an excitation signal.
Output as ds.

Reference numeral 7 denotes an amplification detection circuit that amplifies and detects the induction signal is induced to the sense line group 3 and outputs an amplitude signal as of the induction signal.

The control circuit 8 controls each unit and inputs and calculates signals to obtain coordinate information. In this circuit, a drive address dadrs indicating the excitation line to be selected is given to the excitation scanning circuit 4, and a sense address sadrs indicating the sense line to be selected is given to the sense scanning circuit 5. Also, an amplitude signal as is input to calculate a coordinate value. This control circuit 8 is realized by a microprocessor,
Each operation is performed by a program.

The coordinate indicator 9 is constituted by a resonance circuit including a coil 10 and a capacitor 11. The resonance frequency of this resonance circuit is set around the frequency of the excitation clock dc. It is not always necessary to match.

(Regarding the Scanning and Coordinate Information Calculation Operations of the Coordinate Reading Device) Next, the operations will be described. The control circuit 8 controls the coordinate reading device, and performs the processing of the flowchart shown in FIG. First, the excitation line group 2 and the sense line group 3
And the coordinate information calculation operation will be described.

The control circuit 8 outputs the drive address dadrs and selects one of the excitation lines. (Step 1) As a result, the output of the excitation circuit 6 is connected to the selected excitation line, and the excitation line generates an AC magnetic field. The control circuit 8 is 1
While selecting the excitation line, the sense address sa
drs is output and the sense line group 3 is sequentially selected.

(Step 2) The selected sense line is connected to the amplification detection circuit 7.

In the flowchart of FIG.
The sense lines 3 are sequentially selected at the trace where is determined, but this order may be reversed. In that case, the order of step 4 and step 5 in FIG. 2 is also exchanged.

When the coordinate indicator 9 is not on the sense line plate 1, no signal is induced on the selected excitation line because the excitation line group 2 and the sense line group 3 are orthogonal. However, when the coordinate indicator 9 is placed on the sense line board 1, an induction signal is induced in each sense line of the sense line group 3 according to the positional relationship between the sense line board 1 and the coordinate indicator 9. . An induction signal is generated in the coil 10 by the AC magnetic field generated by the excitation line, and the coil 10 generates an AC magnetic field by the induction signal. This AC magnetic field generates an induction signal on the sense line.

FIG. 3 shows the guide signal is as a timing chart of scanning. FIG. 1 shows an example in which the excitation line group 2 is scanned from the top to the bottom of the figure, and the sense line group 3 is scanned from the left to the right in the figure. The position p of the coil 10 is in a region where the excitation line d2 and the sense line s2 intersect.

Now, in the case where the excitation line d0 and the sense line s0 are selected, that is, the region where both intersect is the coil
If the position p is far away from the position p, the induction signal is not observed. As the region where the excitation line and the sense line intersect approaches the position p of the coil 10, the induction signal is increased, and becomes maximum when the excitation line d2 and the sense line s2 are selected. The induction signal is has a distribution as shown in the timing chart of FIG.

The induction signal is converted into an amplitude signal as by the amplification detection circuit 7, and the magnitude is read by the control circuit 8. (Step 3) The input of the control circuit 8 is an A / D conversion circuit, which reads the magnitude of the amplitude signal as as a digital quantity.

The control circuit 8 repeats the above processing for a range in which an induction signal necessary for calculating a coordinate value can be obtained, for example, a range of five excitation lines and five sense lines.

(Steps 4 and 5) This scanning is called "scanning".

When one scan is completed, calculation of coordinate information (step 6) is performed by the following method. The control circuit 8 selects the signals isp, isx as shown in the timing chart of FIG.
The amplitude signals of l, isxh, isyl, and isyh are detected, and the coordinate information of the position where the coordinate indicator 10 is placed is calculated by Expression 1.

Where isxl> isxh n is a constant and However, isxh> isxl (Formula 1) Although Formula 1 shows only one axis of the XY coordinate system, the same applies to the second axis. The following description is also made only for one axis. The value Qx in Equation 1 has the following properties. This will be described with reference to FIG. First, when the coil 10 is placed at the center of a certain sense line (FIG. 4 (a)), the induction signals isxl and isxh on both sides of isp are equal, and Qx = n. coil
When 10 moves and becomes between the sense line that induced isp and the sense line that induced isxh (FIG. 4 (b)), isp and isxh become equal, and QX = 0.
While the coil 10 moves from the center of a certain sense line to the boundary with the next sense line, Qx takes a value between n and 0.

This relationship shows the opposite tendency on the left and right from the center of the sense line, and shows the same tendency for each sense line. That is, it indicates information on where the coil 10 is located between the sense lines. This information is called coordinate information here.

Although not the gist of the present invention, the position of the entire sense line plate can be obtained from the sense line number and the coordinate information obtained here, and this is used as the coordinate value.

(Regarding Operation for Calculating Height Information) Next, an operation for calculating height information will be described. The control circuit 8 controls the amplitude signal as of the induction signal input during the scanning.
Guidance signal isp used to calculate coordinate information from
Is extracted as a height detection signal. (Step 7) This signal is increased or decreased according to the position and height of the coordinate indicator as described in the background art.

In this case, isp can be defined as a guide signal of a sense line closest to the coordinate indicator 9. This signal is an example of "a guidance signal guided to a sense line in a specific positional relationship with the position where the coordinate indicator is placed" claimed in the claims, and is not limited to isp. . For example, even in isxl, the coordinate indicator and the sense line that induced this signal have a specific relationship, and the magnitude is larger or smaller depending on the position and height of the coordinate indicator. Similarly, a height detection signal can be used.

When the amplitude signal of the induction signal isp is adopted as the height detection signal, and the height is constant, the relationship between the position in the sense line and the height detection signal is the same as that in FIG. On the other hand, the coordinate information has the relationship shown in FIG. As described above, since the coordinate information and the height detection signal have a fixed relationship with respect to the position in the sense line, the height detection signal is corrected by the coordinate information so that the height detection signal is not affected by the position. can do. This is the gist of the present invention.

Since the relationship between the coordinate information and the correction amount of the height detection signal is complicated, a conversion table from the coordinate information to the correction amount is adopted for realization. FIG. 5 is an explanatory diagram of a conversion table of a height detection signal. First, the relationship between the coordinate information and the correction amount is examined by an experiment, and the relationship is stored in the form of a conversion table. The conversion table is searched based on the coordinate information calculated in step 6, and a correction amount is obtained. This correction amount is added to or subtracted from the height detection signal.

FIG. 5 shows an example of a conversion table in which n = 255 in Equation 1 for calculating the coordinate information Qx. This table shows coil 1
The amount by which the height detection signal decreases as 0 moves from the center to the periphery of the sense line is registered as a correction amount.
Using this conversion table, for example, it is assumed that the coil 10 has moved to a considerable periphery of the sense line and Qx = 20 has been obtained as coordinate information. The correction amount corresponding to Qx = 20 is 27,
This is added to the height detection signal.

Finally, the height detection signal corrected as described above is converted into height information. (Step 8) Since the tendency of the height detection signal with respect to the height does not become a linear tendency, some conversion is required. This processing also depends on the height-
The relationship between the height detection signals was obtained, and this was implemented as a conversion table. The conversion method is the same as the above-described method of correcting the height detection signal, and thus the description is omitted.

(Structure of the coordinate reading device according to the second embodiment) The gist of the present invention is that an amplitude signal of a guidance signal guided to a sense line having a specific relationship with a position where a coordinate indicator is placed is determined by the coordinate information. Correcting the influence and obtaining height information. Therefore, the means for generating the induction signal on the sense line is not limited to the first embodiment.

FIG. 6 is a configuration diagram of the second embodiment. As shown in the figure, in the case of this embodiment, the excitation line group 22 is arranged in the same direction as the sense line group 3 without being orthogonal. In addition, the two are partially overlapped. Other configurations are the same as those of the first embodiment.

With the sense line plate 21 configured in this manner, the excitation circuit 4
To select one excitation line and give an excitation signal,
At the same time, when one sense line overlapping this excitation line is selected, an induction signal is generated in this sense line by electromagnetic coupling with the excitation line.

The difference from the first embodiment is that an induction signal is generated even when the coordinate indicator 9 is not on the sense line board 21. However, when the coordinate indicator 9 is placed on the sense line board 21, the coupling becomes stronger and a large induced signal is generated. Therefore, the coordinate information can be obtained by observing the amplitude of the guide signal, and the height detection signal can be extracted. The processing for calculating the height information is the same as in the first embodiment.

(Configuration of Coordinate Reading Apparatus According to Third Embodiment) The first and second embodiments are embodiments of the wireless coordinate reading apparatus. FIG. 7 is a block diagram of an embodiment of a coordinate reading apparatus in which an excitation circuit is connected to a coordinate indicator to generate an AC magnetic field.

The excitation circuit 6 is connected to the coil 51 in the coordinate indicator 50 by a signal line. The figure shows only one axis of the XY coordinate system. If two sets of the sense line group 3 and the sense scanning circuit 5 are provided, and they are arranged orthogonally to each other, a coordinate reading device capable of obtaining XY coordinates can be configured. .

In the coordinate reading device having this configuration, by scanning the sense line group 3, it is possible to detect a guidance signal guided to the sense line group 3. Although the details are omitted, the distribution of the guide signal is the same as in the above embodiment, and the height information can be calculated by the same processing.

Furthermore, in the above-described first to third embodiments, examples are shown in which the coordinate indicator and the sense line are electromagnetically coupled. However, the present invention is limited by means for generating an induction signal on the sense line. Therefore, the present invention can be applied to a coordinate reading device employing another principle. For example, a coordinate reading device based on the principle of electrostatic induction has been realized. In a coordinate reading device based on this principle, a system that scans a sense line can detect a height detection signal from an induction signal. This can be corrected with the coordinate information to calculate the height information.

[Effects of the Invention] As described above, in the present invention, the position where the coordinate indicator is placed and the specific position are selected from the guidance signals guided to the sense line group by coupling between the coordinate indicator and the sense line. The amplitude of the guide signal of the relevant sense line is extracted as a height detection signal, and this is corrected by the coordinate information calculated from the distribution of the guide signal to obtain a height detection signal that is not affected by the position. The coordinate reading device was configured to convert the information into height information. A coordinate reading device capable of accurately obtaining height information without being affected by position has been realized.

[Brief description of the drawings]

FIG. 1 is a block diagram of a first embodiment of a wireless coordinate reading device according to the present invention, FIG. 2 is a flowchart of processing of a control device, FIG. 3 is a timing chart of generation of a guidance signal, and FIG. 5, FIG. 5 is an explanatory diagram of a conversion table of height detection signals, FIG. 6 is a configuration diagram of the second embodiment, and FIG.
FIG. 8 is an explanatory diagram of a conventional height detecting technique, and FIG. 9 is a distribution diagram of the amplitude of an induced signal. DESCRIPTION OF SYMBOLS 1 ... Sense line board 2 ... Excitation line group 3 ... Sense line group 4 ... Excitation scan circuit 5 ... Sense scan circuit 6 ... Excitation circuit 7 ... Amplification detection circuit 8 ... Control circuit 9 ... Coordinate Indicator 10 …… Coil 11 …… Capacitor

Claims (3)

(57) [Claims] A. A coordinate indicator for indicating a coordinate reading point; b. A sense line group for generating an induction signal based on the connection with the coordinate indicator; c. A. A scanning circuit for selectively scanning this; d. An amplification detection circuit connected to the scanning circuit for detecting the amplitude signal of the induction signal; and e. Controlling each part of the coordinate reading device and placing the coordinate indicator. A. A coordinate reading device comprising: a control circuit for calculating a coordinate value of the position thus set; f. Applying a selection signal to the scanning circuit to select the sense line group and inputting an amplitude signal of the induction signal; G. A process of calculating coordinate information based on the input amplitude signal; and h. A guide from the amplitude signal to a sense line having a specific positional relationship with the position of the coordinate indicator. Height detection of amplitude signal of induction signal A process of calculating height information of a position where the coordinate indicator is placed based on the height detection signal and the coordinate information. Information calculation method. A. A coordinate indicator for indicating a coordinate reading point; b. A sense line group for generating an induction signal based on the connection with the coordinate indicator; c. A. A scanning circuit for selectively scanning this; d. An amplification detection circuit connected to the scanning circuit for detecting the amplitude signal of the induction signal; and e. Controlling each part of the coordinate reading device and placing the coordinate indicator. A coordinate reading device comprising: a control circuit that calculates a coordinate value of the position that has been placed; f. A coordinate information calculation circuit that calculates coordinate information based on an amplitude signal that is input along with the scanning; g. From among the amplitude signals, a height signal detection circuit that extracts, as a height detection signal, an amplitude signal of a guidance signal guided to a sense line in a specific positional relationship with the position where the coordinate pointer is placed, h. The height detection signal and the coordinate information The coordinate height information calculating circuit for calculating height information of the placed position of indicator, the coordinate reading device which comprises a city by the. 3. The coordinate reading apparatus according to claim 1, wherein said coordinate indicator and said sense line group generate an induction signal in said sense line group based on electromagnetic coupling. The coordinate information reading method according to claim 2 or a coordinate reading device according to claim 2.