JPH0447319A - Height information calculating system in coordinate reading device - Google Patents

Abstract

PURPOSE:To detect even the height information of a coordinate indicator by calculating coordinate information based on an induced signal, extracting the amplitude signal of the induced signal induced in a sense line positioned in specified positional relation with a position where the coordinate indicator is placed as a height detection signal, and calculating the height information by using this extracted signal and the coordinate information. CONSTITUTION:In a process to select sequentially a sense line group 3, if the coordinate indicator 9 is placed in the vicinity of the selected sense line, the induced signal is generated in the sense line by an AC magnetic field which the coordinate indicator 9 generates. A control circuit 8 compares and operates the amplitude of these plural induced signals, and obtains the coordinate information. On the other hand, when the amplitude of the induced signal induced in the sense line in the specified positional relation with the coordinate indicator 9 is noticed, this becomes the signal to vary according to the position and the height of the coordinate indicator 9. The control circuit 8 calculates the height information by using this extracted signal and the coordinate information. Thus, the height information can be highly precisely obtained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a coordinate reading device that inputs coordinates to an external device such as a computer, and relates to a reading device that can calculate height information in addition to coordinate values. This relates to a method of calculating height information.

[Summary of the Invention] The present invention provides a coordinate reading device that, when a coordinate indicator that generates an alternating magnetic field is placed on a sense line, obtains coordinate values from a guided signal guided to the sense line by tt magnetic coupling between the two. It is an object of the present invention to realize a coordinate reading device that can also detect height information of a position where a coordinate indicator is placed.

To this end, in the present invention, in a control device that controls each part of the coordinate reading device and calculates coordinate values at the same time, coordinate information is calculated based on the guidance signal, and a specific positional relationship between the position of the coordinate indicator and the specific positional relationship is determined. The amplitude signal of the guidance signal guided to the sense line located at is extracted as a height detection signal, and height information is calculated from this and the coordinate information.

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

The excitation line 102 and the sense line 103 are arranged orthogonally to form the sense line plate 101, and the excitation line 102
An alternating current signal is applied to the sense line 103, and the induced signal induced on the sense line 103 is observed. The coordinate indicator 104 is a coil 105
It has a built-in resonant circuit using a capacitor.

When the coordinate indicator 104 is placed on the sense line plate 101 as shown in the figure, an induced signal is generated on the sense line 103 due to the magnetic coupling between 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 guidance signal will increase, and if it moves away from the sense line plate 101, the amplitude will decrease.If the guidance signal is amplified and detected and the amplitude is measured, the coordinate indicator The height information can be obtained.

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

For this reason, with the technology that uses the amplitude of the guidance signal as height information, the amplitude changes depending on the position on the plane where the coordinate indicator is placed, so there is a problem that height information cannot be detected accurately. there were.

For example, the coordinate indicator 104
As the sense line 103 moves, the amplitude of the induced signal becomes maximum at the center of the sense line 103 and decreases as it moves toward the periphery, as shown in FIG.

The present invention has been made to solve the above-mentioned problems in the conventional technology. The main purpose is to realize a coordinate reading device that can also detect the height information of the position where the coordinate indicator is placed, and the more specific purpose is to:
An object of the present invention is to realize a coordinate reading device that can detect height information with high precision without being affected by position.

[Means for Solving the Problems] In order to solve the above problems, the present invention connects a coordinate indicator that generates an alternating magnetic field, a sense line group that generates an induction signal by the alternating magnetic field, and a sense line group, a scanning circuit for selecting one sense line; and a scanning circuit connected to the scanning circuit;
Selected as a scanning circuit in a coordinate reading device consisting of an amplification/detection circuit that detects the amplitude signal of the guidance signal, and a control circuit that controls each part of the coordinate reading device and calculates the coordinate value of the position where the coordinate indicator is placed. A process of applying a signal, selecting a sense line group, and inputting the amplitude signal of the induced signal,
Processing that calculates coordinate information based on the input amplitude signal, height detection of the amplitude signal of the guidance signal guided to the sense line that has a specific positional relationship with the position where the coordinate indicator is placed from among the amplitude signals A coordinate reading device was constructed by providing a control circuit with a process of extracting the signal as a signal and a process of calculating the height information of the position where the coordinate indicator is placed based on the height detection signal and the coordinate information.

[Function] In the coordinate reading device configured as described above, if a coordinate indicator is placed near a selected sense line in the process of sequentially selecting a sense line group, the coordinate indicator will be generated. An induced signal is generated in the sense line by the alternating magnetic field.

The control circuit compares and calculates the amplitudes of these plurality of guidance signals to obtain coordinate information.

On the other hand, among the guidance signals, if we pay attention to the amplitude of the guidance signal guided to the sense line in a specific positional relationship with the coordinate indicator, this changes depending on the position and height of the coordinate indicator. The control circuit calculates height information using this signal and coordinate information.

[Embodiment] (Configuration of coordinate reading device according to first embodiment) A first embodiment of the present invention will be described below with reference to FIGS. 1 to 4. The first embodiment is an application of the present invention to a wireless coordinate reading device that does not require a signal line to connect the coordinate reading device main body and a coordinate indicator.

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

In FIG. 1, 1 is 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 and are arranged at regular intervals.

4 is 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 switching elements such as analog switches, and is adapted to apply an excitation signal ds supplied from an excitation circuit 6, which will be described later, to one selected excitation line.

5 is 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 composed of electronic switching elements, and one of the sense lines is selected and connected to an amplification/detection circuit 7, which will be described later.

6 is an excitation circuit. An excitation clock dc is inputted from a control circuit 8, which will be described later, and is waveform-shaped and amplified to be output as an excitation signal ds.

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

The control circuit 8 controls each part, inputs signals, performs calculations, and obtains coordinate information. This circuit provides the excitation scanning circuit 4 with a drive address dadrs indicating the excitation line to be selected, and the sense scanning circuit 5 with a sense address 5adrs indicating the sense line to be selected. Furthermore, an amplitude signal as is input to calculate coordinate values. This control circuit 8 is realized by a microprocessor, and each calculation process is performed by a program.

The coordinate indicator 9 is constituted by a resonant circuit including a coil 10 and a capacitor 11. The resonant frequency of this resonant circuit is set around the frequency of the excitation clock dc.

They do not necessarily have 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 shown in the flowchart shown in FIG. 2. First, the operation of selecting the excitation line group 2 and the sense line group 3 and the coordinate information calculation operation will be explained.

The control circuit 8 outputs a drive address dadrs to select one of the excitation lines. (St.

1) This connects the output of the excitation circuit 6 to the selected excitation line, and the excitation line generates an alternating current magnetic field.

While selecting one excitation line, the control circuit 8 outputs the sense address 5adrs to sequentially select the sense line group 3.

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

In the flowchart of FIG. 2, the sense line group 3 is sequentially selected after the excitation line group 2 is determined, but this order may be reversed. In that case,
The order of steps 4 and 5 in FIG. 2 is also exchanged.

If the coordinate indicator 9 is not on the sense line plate 1, no signal will be induced to the selected excitation line because the excitation line group 2 and the sense line group 3 are perpendicular to each other. When the indicator 9 is placed on the sense line board 1, each sense line of the sense line group 3 is guided by a guidance signal is corresponding 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 alternating magnetic field generated by the excitation line, and the coil 10 generates an alternating magnetic field due to this induction signal. This alternating magnetic field generates an induced signal on the sense line.

FIG. 3 shows the guidance signal is as a scanning timing diagram. Taking FIG. 1 as an example, 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. Positions W and P of the coil 10 are located in the area where the excitation line d2 and the sense line S2 intersect.

Now, when the excitation line dO and the sense line SO are selected, that is, when the area where they intersect is far away from the position p of the coil 10, the induction signal is
is not observed, and as the region where the excitation line and the sense line intersect approaches the coil 10 Wp, the induced signal iS
becomes large and reaches its maximum when the excitation line d2 and the sense line S2 are selected. The guidance signal is has a distribution as shown in the timing diagram of FIG.

The induced signal is is converted into an amplitude signal as by the amplification/detection circuit 7.
, and its magnitude is read by the control circuit 8. (The input of the step 3 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 process for a range in which the induction signals required for coordinate value calculation can be obtained, for example, a range of five excitation lines and five sense lines.

(Step 4, Step 5) This operation is called "scanning".

When one scan is completed, the coordinate information is calculated (step 6) using the following method.The control circuit 8 calculates the signal isp as shown in the timing diagram of FIG. 3 from the read amplitude signal as.
Amplitude signals of 1sxl, 1sxh, 1syL 1syh are detected, and coordinate information of the position where the coordinate indicator 10 is placed is calculated using Equation 1.

However, 1sxl>1sxh n is a constant, and 1sxh>1sxl (Equation 1) Although Equation 1 shows only one axis of the XY coordinate system, the same applies to the second axis. The following explanation will also be made regarding only one axis.

The value Qx of 21 has the following properties. This will be explained with reference to FIG. First, when the coil 10 is placed at the center of a certain sense line (FIG. 4(a)), the induced signals 1sxl and 1sxh on both sides of the isp are equal, and Qx=n. When the coil 10 moves and becomes between the sense line that induced tsp and the sense line that induced jsxh (FIG. 4(b)), isp and 1sxh become equal, and QX=O. Qx takes a value between n and 0 while the coil 1o moves from the center of one sense line to the boundary with the next sense line.

This relationship shows opposite trends on the left and right sides of the center of the sense line, and also shows the same tendency for each sense line.
In other words, it shows information on where the coil 1o is located between the sense lines. This information is called coordinate information here.

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

(About the operation of calculating height information) Next, the operation of calculating height information will be explained.

The control circuit 8 extracts the amplitude information of the guidance signal isp used to calculate the coordinate information from the amplitude signal asO of the guidance signal inputted during scanning, and uses it as a height detection signal. (Step 7) As explained in the prior art, this signal changes in size depending on the position and height of the coordinate indicator.

In this case, isp can be defined as the guidance signal of the 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" as claimed in the claims, and is not limited to ISP. For example, even in 1sxl, there is a specific relationship between the coordinate indicator and the sense line that guided this signal, and the size varies depending on the position and height of the coordinate indicator. Similarly, it can be used as a height detection signal.

When the amplitude signal of the induction signal isp is employed as the height detection signal, the relationship between the position within the sense line and the height detection signal is similar to that shown in FIG. 8, assuming that the height is constant. On the other hand, the coordinate information had the relationship shown in FIG. In this way, the coordinate information and height detection signal have a fixed relationship with respect to the position within the sense line, so 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 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 used to realize this. FIG. 5 is an explanatory diagram of a conversion table for height detection signals. First, the relationship between the coordinate information and the amount of correction is investigated through experiments, and the result is stored in the form of a conversion table.In step 6, the conversion table is searched using the coordinate information obtained in the summer, and the amount of correction is determined.

This correction amount is added to or subtracted from the height detection signal.

The case shown in FIG. 5 is an example of a conversion table in which n=255 in Equation 1 for converting the coordinate information Qx.

In this table, the amount by which the height detection signal decreases as the coil 10 moves from the center of the sense line to the periphery is registered as a correction amount. For example, suppose that the coil 10 is moved to a considerable position around the sense line using this conversion table, and Qx-20 is obtained as coordinate information. QX-20
The correction amount corresponding to is 27, and 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 height is not a linear tendency, some kind of conversion is required. This process was also carried out by determining the relationship between height and height detection signal through experiments and using this as a conversion table. The conversion method is the same as the height detection signal correction method described above, so a description thereof will be omitted.

(Configuration of coordinate reading device according to second embodiment) The gist of the present invention is to change the amplitude signal of a guidance signal guided to a sense line having a specific relationship with the position where a coordinate indicator is placed, depending on the position using coordinate information. The purpose is to correct the influence and obtain height information. Therefore, the means for causing the sense line to contain the induced signal is not limited to the first embodiment.

FIG. 6 is a block diagram of the second embodiment. As shown in FIG. 0, in this embodiment, the excitation line group 22 is not perpendicular to the sense line group 3 but is arranged in the same direction. Furthermore, the two overlap in part. The other configurations are similar to the first embodiment.

With the sense line plate 21 configured in this way, the excitation circuit 4
Select one excitation line and give an excitation signal by
If one sense line that overlaps this excitation line is selected at the same time, an induced signal is generated in this sense line due to 1f magnetic coupling with the excitation line.

The difference from the first embodiment is that a guidance signal is generated even if the coordinate indicator 9 is not on the sense line plate 21. However, when the coordinate indicator 9 is placed on the sense line plate 21, the coupling becomes stronger and a larger induced signal is generated. Therefore, coordinate information can be obtained by observing the amplitude of the guidance signal, and the height detection signal can also be extracted. The process of converting the height information is the same as in the first embodiment.

(Configuration of coordinate reading device according to third embodiment) The first and second embodiments are examples of a wireless coordinate reading device. FIG. 7 is a configuration diagram of an embodiment of a coordinate reading device in which an excitation circuit is connected to a coordinate indicator to generate an alternating magnetic field.

Figure 0, in which the excitation circuit 6 is connected to the coil 51 in the coordinate indicator 50 by a signal line, shows only one axis of the XY coordinate system, and the sense line group 3 and sense scanning circuit 5 are connected to the two.
By providing a set and arranging them perpendicularly to each other, a coordinate reading device capable of determining XY coordinates can be constructed.

The coordinate reading device having this configuration can detect the guiding signal guided to the sense line group 3 by scanning the sense line group 3. Although the details are omitted, the distribution of the guidance signal is the same as in the above embodiment, and the height information can also be calculated by the same process.

[Effects of the Invention] As explained above, in the present invention, between the coordinate indicator that generates an alternating magnetic field and the sense line! Among the induction signals induced in the sense line group by magnetic coupling, the amplitude of the induction signal of the sense line in a specific positional relationship with the position where the coordinate indicator is placed is extracted as a height detection signal, and this is used as a height detection signal. The coordinate reading device was configured to correct the height detection signal using coordinate information calculated from the distribution of the guidance signal to obtain a height detection signal that is not affected by position, and then convert this into height information.

We were able to realize a coordinate reading device that can accurately obtain height information without being affected by position.

[Brief explanation of the drawing]

FIG. 1 is a block diagram of a first embodiment of a wireless coordinate reading device according to the present invention, and FIG. A flowchart of the processing of the Il device, Fig. 3 is a timing diagram of the generation of the guidance signal, and Fig. 4 is a diagram of the generation timing of the guidance signal.
The figure is a distribution diagram of coordinate information Qx, 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. 7 is a configuration diagram of the third embodiment. FIG. 8 is an explanatory diagram of the conventional height detection technique, and FIG. 9 is a distribution diagram of the amplitude of the guidance signal. 1...Sense line plate 2...Excitation line group 3...Sense line group 4...Excitation scanning circuit 5...Sense scanning circuit 6... - Excitation circuit 7... Amplification/detection circuit 8... Control circuit 9... Coordinate indicator 10... Coil 11... Capacitor Applicant: Seiko Electronics Co., Ltd. Company agent Patent attorney Takayuki Hayashi Configuration diagram of an embodiment of moving unit 1 1. System vs. device processing flowchart 2. O Guidance signal generation timing-diagram 3. Coordinate information Qx distribution diagram 4. Conversion table for the eye height detection signal Explanation of the conversion table for the height detection signal Explanatory diagram of the height detection technology Distribution diagram of the amplitude of the 8th eye guidance signal Small square

Claims (1)

[Claims] a. A coordinate indicator that generates an alternating magnetic field; b. A sense line group that generates an induction signal by the alternating magnetic field; c. Connecting the sense line group and selecting one sense line. d. An amplification/detection circuit connected to the scanning circuit and detecting the amplitude signal of the guidance signal; e. Controlling each part of the coordinate reading device and determining the coordinates of the position where the coordinate indicator is placed. A coordinate reading device comprising: a control circuit that calculates a value; the control circuit: f; applies a selection signal to the scanning circuit to select the sense line group; and an amplitude signal of the guiding signal; g. Calculating coordinate information based on the input amplitude signal; h. From among the amplitude signals, select a sense line that has a specific positional relationship with the position where the coordinate indicator is placed. a process of extracting an amplitude signal of the guided guidance signal as a height detection signal; i) a process of calculating height information of the position where the coordinate indicator is placed based on the height detection signal and the coordinate information; A height information calculation method in a coordinate reading device, including: