JPH03175522A - Coordinate reader - Google Patents

Abstract

PURPOSE:To obtain and output inclination information of a coordinate indicator by detecting a main peak signal group and secondary peak signals existing before and after this signal group from a guidance signal and dividing the difference between secondary peak signals by the sum of the main peak signal group. CONSTITUTION:A main peak signal group detecting circuit 51 which detects main peak signal groups, which exist in the vicinity of the main peak signal having a maximum amplitude and have the same phase, from the guidance signal, first and second secondary peak detecting circuits 52 and 53 which detect secondary peak signals which exist before and after the main peak signal group and have a maximum value of the guidance signal whose phase is opposite to that of the main peak signal, a main peak signal group adding circuit 54 which obtains the sum of amplitudes of the main peak signal group, a secondary peak difference circuit 55 which obtains the difference between first and second secondary peaks, and an inclination information calculating circuit 56 which divides the difference between secondary peaks by this sum of amplitudes to output inclination information of a coordinate indicator 2 are provided. Thus, inclination information of the coordinate indicator 2 is outputted to the external.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an external device such as a computer and a coordinate reading device that performs coordinate reading, and particularly relates to an electromagnetic induction type coordinate reading device that applies electromagnetic induction phenomena. It is something.

(Summary of the Invention) An object of the present invention is to provide a coordinate reading device that can output tilt information to the outside when a coordinate indicator is placed tilted on a sense line.

The m& coordinate reading device to which the present invention is directed calculates coordinate values by calculating the amplitude of a guidance signal induced to a sense line by an electromagnetic induction phenomenon between a sense line and a coordinate indicator. It is.

In order to achieve the above object, the present invention detects, from a guided signal, a group of main peak signals that include a main peak signal with the largest amplitude and that are in the same phase and that reside in the vicinity of the main peak signal. a main peak signal group detection circuit; a second secondary peak detection circuit; a main peak signal group addition circuit that calculates the sum of the amplitudes of the main peak signal group; a secondary peak difference circuit that calculates the difference between the first and second secondary peaks; A tilt information calculation circuit is provided which divides the peak difference by the sum of the amplitudes of the main peak signal group and outputs coordinate indicator tilt 1a information.

[Prior Art] In an electromagnetic induction type coordinate reading device, a guided signal induced to a sense line in the vicinity of a coordinate indicator is inputted and processed by sequentially selecting the sense lines, and the amplitudes are compared and calculated. Find the coordinates.

FIG. 2 is an explanatory diagram showing the amplitude of the guidance signal along the time axis. Vp is the main peak signal, and the coordinate indicator is located near the sense line from which this signal is induced. Since the spacing between the sense lines is rougher than the resolution of the coordinate values normally obtained, more detailed positions between the sense lines can be determined by comparing 11.1 Vp with the Vpl and Vph before and after it7.
Find it by calculating.

In FIG. 2, Vph>Vpl, indicating that the coordinate indicator is displaced in the scanning direction (the direction of the sense line that induced Vph) rather than the sense line that induced Vp. By arithmetic processing of Vp, Vpl, and Vph, coordinate values can be obtained with a predetermined resolution, for example, Q, in units of 1 mm.

[Problem to be solved by the invention] However, in conventional coordinate input devices, when the coordinate indicator is tilted, the distribution of the 16-lead signals on the sense line changes, and the coordinate values also change accordingly. There was a problem.

There is a type of coordinate indicator called a stylus pen, which is particularly problematic when used.

FIG. 3 is an explanatory diagram showing the amplitude of the guidance signal along the time axis when the coordinate indicator is tilted, similar to FIG. 2. The coordinate indicator is a stylus pen, and the tip of the pen is in the same position as in FIG.

Further, the direction of the inclination is the direction in which the sense line is scanned.

As shown in FIG. 3, there is a tendency that the induced voltage in the direction in which the pen is tilted, that is, Vph, increases, and conversely, Vpl decreases. For this reason, the coordinate values are displaced in the direction in which the pen is tilted.

The present invention has been made to improve these drawbacks. A main object of the present invention is to provide a coordinate reading device that can output inclination information of a coordinate indicator to the outside. This allows the external device to correct the tilt error in the coordinate values output by the coordinate reading device, or to use the tilt information by giving it its own meaning.

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an electromagnetic induction coordinate reading device that includes a main peak signal with the maximum amplitude from a guided signal, and detects signals that are identical to each other in the vicinity of the main peak signal. A main peak signal detection circuit detects the main peak signal group of the phase, and first and second peak signal detection circuits exist before and after the main peak signal group and are the maximum values of the induction signals that are in opposite phase to the main beam 9 signal. A first and second secondary peak detection circuit detects a secondary peak signal, a main peak signal mixing and addition circuit calculates the sum of the amplitudes of the main peak signal group, and a main peak signal mixing circuit calculates the difference between the first and second secondary peaks. A secondary peak difference circuit for determining the secondary peak and a slope information calculation circuit that divides the difference between the secondary peaks by the sum of the amplitudes of the main peak signal group and outputs slope information of the coordinate indicator are provided.

[Function] According to the coordinate reading device according to the present invention, the main beak signal group and the first and second secondary peak signals can be detected from the guided signals guided to the sense line. The main peak signals are added together, and the difference is determined from the secondary peaks.

It has been found through experiments that the difference between the secondary peaks has information on the inclination of the coordinate indicator. However, this 11'1 report is
It is also known that it is affected by the average magnitude of the induced signal. Ag'sl! The average magnitude of the signal changes depending on the distance between the coordinate indicator and the sense line, the gain of the signal processing circuit, etc.

On the other hand, it was also found that the sum of the main beak signals represents the average magnitude of the above-mentioned induced signals.

Based on the above experimental results, the coordinate reading device according to the present invention is designed to divide the difference between secondary peaks by the sum of the main beak signal group. In this way, it is possible to obtain inclination information independent of the magnitude of the guide (J).

[Example 1] An example of the present invention will be described below with reference to FIGS. 1 and 4 to 6.
This will be explained based on the diagram.

FIG. 1 shows a block diagram of a coordinate reading device according to the present invention. In the figure, 1 is a sense line group, 2 is a coordinate indicator, 3 is a scanning circuit, 4 is a signal processing circuit, and 5 is a control circuit.

To explain the control circuit 5 in detail, 51 is a main peak signal group detection circuit, 52 is a first secondary peak detection circuit, and 53
54 is a second secondary peak detection circuit, 54 is a main peak signal group addition circuit, 55 is a secondary peak difference circuit, 56 is a slope information calculation circuit, and 57 is a coordinate calculation circuit.

In the sense line group shown in FIG. 1, the coordinate detection direction is only horizontal. By arranging two sense line groups so that they are orthogonal to each other, coordinate values and inclination information in the xY rectangular coordinate system can be obtained. However, since the operation in this case is the same as that for one axis, the following explanation will be made for one axis according to FIG.

Next, the operation will be explained.

(Operation of inputting a guidance signal) The control circuit 5 outputs the scanning signal sl to the scanning circuit 3. The scanning circuit 3 receives this signal and sequentially selects the sense line group 1. A coordinate indicator 2 is placed on the sense line group l.

(The vote indicator has a coil inside and generates an alternating current magnetic field. There are various ways to excite the coil, but here it is assumed that the coil is excited by an oscillator and an amplifier (not shown). .Other methods will be described later.

The scanning circuit 3 sequentially outputs the induction signal s2 induced to the sense line group 1 along with the scanning signal s1. The signal processing circuit 4 converts the induced signal s2 into an envelope signal s3.

FIG. 4 is an explanatory diagram of the distribution of the induced signal, and the envelope signal s3
FIG. This figure shows that the guiding signal s2 is generated sequentially over time as the scanning progresses, but it also shows the distribution of the guiding signal for each sense line.

This signal has a large amplitude of the guidance signal near where the coordinate indicator is placed, and becomes smaller as it goes to the periphery.
The distribution tends to take the maximum value again. The local maximum value at the periphery is an effect of a magnetic field that is in an opposite phase relationship with the magnetic field that generates the central maximum value.

(Operation of the main peak signal group detection circuit 51 and the main peak signal group addition circuit 54) The main peak signal group detection circuit 51 detects the envelope No. 18 S3.
, the main peak signal Vp having the maximum amplitude is detected, and a group of main peak signals s4 continuously existing around it and having the same phase as Vp are detected. Practically speaking, if the minimum values existing after ff1N of Vp are detected, the signal group sandwiched between these minimum values becomes the main peak signal group S4. (See FIG. 4) The main peak signal group detection circuit 51 detects the main peak signal ff54 in this manner. To detect the main signal group, of course, the phase may be detected and compared.

The main peak signal group S4 detected by the main peak signal group detection circuit 51 is added by the main peak signal group addition circuit 54, and becomes main peak sum information S5.

(Operation of the first and second secondary peak detection circuits 52 and 53) The secondary peak is a signal that takes a local maximum value that exists before and after the main peak signal group S4, as shown in FIG.

The first secondary peak detection circuit 52 detects the maximum value between the scanning start position and the position of the minimum value existing before the main beak signal group, and sets it as the first secondary peak signal s6.

Similarly, the second secondary peak detection circuit 53 detects the maximum value between the position of the minimum value existing after the main peak signal group and the scanning end position, and detects the maximum value between the position of the minimum value existing after the main peak signal group and the second secondary peak signal s7.
shall be.

(Operation of secondary peak difference circuit 55) The difference between the first and second secondary peaks detected by the first and second secondary peak detection circuits is determined by the secondary peak difference circuit 55, Secondary peak difference information s
It becomes 8.

FIG. 5(a) is an explanatory diagram showing the distribution of the guidance signal when the slope is 0. If the slope is O, the first and second
The magnitudes of the secondary peaks are equal, and the difference between the two is 0, so that secondary peak difference information O is obtained.

FIG. 5(b) is an explanatory diagram showing the distribution of guidance signals when the coordinate indicator is tilted in the scanning direction.

In this case, (first secondary peak)<(second secondary peak>),
When the difference between the two is taken, (first secondary peak) - (second secondary peak) = -dv. The sign of the calculation result indicates the direction of the slope. In this example, it is negative, indicating that the coordinate indicator is tilted in the scanning direction. dv represents the magnitude of the slope.

(Operation of the slope information calculation circuit 56) However, if left as is, dv will fluctuate depending on the average magnitude of the induction (ε).

Fig. 6(a) shows the distribution of induced voltage when the distance between the coordinate indicator and the sense line is small, and Fig. 6(b) shows the distribution when the distance is large. . The positions of the coordinate indicators in both cases along the detection direction are the same. In this case, it is clear that dvl>dv2, and it can be seen that this is not effective as current information.

On the other hand, according to experiments, the main peak peace f
llis5 was found to be representative of the average magnitude of the induced signal. The slope information calculation circuit 56 divides the secondary peak difference information by the main peak sum information. This result shows that the slope information s is not affected by the average magnitude of the guidance signal.
It becomes 9.

(Regarding implementation in other electromagnetic induction type coordinate reading devices) The above explanation is based on connecting a transmitter and an amplifier to a coordinate indicator, and calculating coordinate values from a signal induced on a sense line by a magnetic field generated by the coordinate indicator. However, the detection of inclination information can be similarly carried out in other electromagnetic induction type coordinate reading devices.

For example, in a coordinate reading device for which the present applicant has already applied, one of the sense lines laid perpendicular to the XY force direction is excited, and a resonant circuit is provided in the coordinate indicator.
The configuration is such that when the coordinate indicator is placed on the sense line, electromagnetic induction occurs from the excitation sense line to the detection sense line. A block diagram of this type of coordinate reading device is shown in FIG. Even with this method, the distribution of the 11 conductor numbers on the detection sense line is the same as in the embodiment described above, and the slope information can also be obtained in the same manner.

Another example is an implementation of the method disclosed in Japanese Patent Application Laid-Open No. 63-70326 Position Detection Apparatus. In this type of coordinate reading device, the sense line is temporarily excited, energy is stored in a resonant circuit within the coordinate indicator, and after the excitation is stopped, the coordinate value is obtained from the distribution of the induced signal induced in the same sense line. seek. Also in this method, tilt information can be obtained in the same way as in the embodiment described above.

The essence of the present invention is to detect a secondary peak from a 33i signal obtained by scanning a sense line in an electromagnetic induction type coordinate reading device, and calculate slope information from this signal. Regardless of the principle of generating the induction signal on the line, it can be implemented in any manner.

[Effects of the Invention] As explained above, according to the present invention, in an electromagnetic induction type coordinate reading device, a main biller signal group and secondary peak signals existing before and after the main peak signal group are detected from the induced 4 signal, To realize a coordinate reading device that can obtain tilt information of a coordinate indicator without being affected by the average magnitude of a guidance signal by dividing the difference between secondary peak signals by the sum of a group of main peak signals. I was able to do that.

The external device can use this tilt information to correct tilt errors in coordinate values, making it possible to read coordinates more accurately. Also, this 1rIf [! By assigning a unique meaning to the information, it has become possible to use it as new information other than coordinate information.

[Brief explanation of drawings]

FIG. 1 is a block diagram of a coordinate reading device according to the present invention, and FIG.
The figure is an explanatory diagram of the guidance signal, Figure 3 is an explanatory diagram of the guidance signal when the coordinate indicator is tilted, Figure 4 is an explanatory diagram of the distribution of the guidance signal, and Figure 5 (a) is the guidance when the tilt is O. Figure 5 (b) is an explanatory diagram of the distribution of the signal. Figure 5 (b) is an illustration of the distribution of the guidance signal when tilted in the scanning direction. Figure 6 (a) is the distribution of the guidance signal when the distance between the coordinate indicator and the sense line is small. Explanatory diagram, Figure 6 (b
) is an explanatory diagram of the distribution of guidance signals when the distance between the coordinate indicator and the sense line is large, and FIG. 7 is a block diagram of a second embodiment of the present invention. 1...Sense line group 2...Coordinate indicator 3...Scanning circuit 4...Signal processing circuit 5...Control circuit 51...Main peak Signal processing circuit 52...
... First secondary peak detection circuit 53 ... Second
Secondary peak detection circuit 54 ... Main peak signal group subtraction circuit 55 ... Secondary peak difference circuit 56 ... Slope information calculation circuit Coordinate detection direction No. 10 Figure 2 Figure 3 Leading Illustration of the distribution of the signal Fig. 4 Illustration of the distribution of the guidance signal in the case of llJ and O Fig. 5 (a) Illustration of the distribution of the guidance signal in the case of tilting in the scanning direction Figure 5 (b) Illustration of the distribution of the guidance signal in the case of small Figure 6 (a) is an explanatory diagram of the distribution of the induced signal when it is large (Figure 6 (Cb))

Claims (2)

[Claims] (1) a. A plurality of sense line groups laid at equal intervals in the direction of detecting coordinates and parallel to each other; b. The sense line group is placed on the sense line group and is caused by electromagnetic induction. c. a scanning circuit that sequentially selects the sense line group; d. a signal processing circuit that is connected to the scanning circuit and processes the guided signal guided to the sense line group. , e. By controlling the scanning circuit, sequentially inputting the guidance signal induced to each sense line from the signal processing circuit, and calculating the amplitude of the guidance signal, the position where the coordinate indicator is placed is determined. and a control circuit for determining the coordinates of f, the control circuit detects a main peak signal having the maximum amplitude from among the induced signals f, and detects a main peak signal having the maximum amplitude and having the same phase as the main peak signal. , a main peak signal group detection circuit that detects a main peak signal group that exists continuously in the main peak signal, g. a first secondary peak detection circuit that detects a first secondary peak signal that is the maximum value of the induced signal that is the phase; h. A second secondary peak signal that is the maximum value of the induced signal that is in opposite phase to the signal group is detected.
i, a main peak signal group addition circuit that calculates the sum of the amplitudes of the main peak signal group; j, a secondary peak difference circuit that calculates the difference between the first and second secondary peaks; k, a tilt information calculation circuit that divides the difference between the secondary peaks by the sum of the amplitudes of the main peak signal group and outputs tilt information of the coordinate detection direction of the coordinate indicator. Coordinate reading device. (2) a. A plurality of sense line groups laid at equal intervals in the X and Y directions of the XY rectangular coordinate system and parallel to each other, and b. Electromagnetic induction placed on the sense line group. c. an X scanning circuit and a Y scanning circuit that sequentially select the sense line group; d. a coordinate indicator connected to the X scanning circuit and the Y scanning circuit, and a signal processing circuit that processes the guided signals guided to the line group; and a control circuit that calculates the X and Y coordinates of the position where the coordinate indicator is placed by calculating the amplitude of the guidance signal in each of the direction and the Y direction, the control circuit comprising: The circuit detects the main peak signal with the maximum amplitude from among the f induced signals in each of the X direction and the Y direction, and detects the main peak signal that is in the same phase as the main peak signal and exists continuously with the main peak signal. g. A main peak signal group detection circuit that detects a main peak signal group that is a main peak signal group; g. a first secondary peak detection circuit that detects a certain first secondary peak signal; h. A first secondary peak detection circuit that detects a certain first secondary peak signal, h. a second second peak signal that is the local maximum value of the signal;
i, a main peak signal group addition circuit that calculates the sum of the amplitudes of the main peak signal group; j, a secondary peak difference circuit that calculates the difference between the first and second secondary peaks; k, a tilt information calculation circuit that divides the difference between the secondary peaks by the sum of the amplitudes of the main peak signal group and outputs tilt information in the X direction and Y direction of the coordinate indicator. coordinate reading device.