JPH01267720A - Coordinate input device - Google Patents

Abstract

PURPOSE:To obtain a fixed reading degree by providing a first threshold deciding part, a position specifying part, an inducing signal correcting part and a second threshold deciding part. CONSTITUTION:A first threshold deciding means 5a, an inducing signal correcting means 5c and a second threshold deciding means 5b are provided. The first threshold deciding means 5a decides whether the maximum value of an inducing signal 8 to be detected is larger than a threshold to be set beforehand or not, and when the value is larger than the threshold, the position of a coordinates indicator 2 is specified by means of a position specifying means 5 by comparing the inducing signals of respective electrode lines x1-xn and y1-ym. An inducing signal correcting means 5c corrects the maximum value of the inducing signal 8 by the specified position so as to be fixed independently of the position of the coordinates indicator 2. The second threshold deciding means 5d decides whether the corrected value is larger than the threshold to be set beforehand or not, and when the value is larger than the threshold, coordinates are finally calculated. Since whether to calculate the coordinates or not is decided by the second threshold deciding means 5d, the reading degree of the coordinates indicator 2 can be made fixed on a tablet.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a coordinate input device, and more particularly to an improvement in a signal detection method of a coordinate input device used for inputting coordinates of a combinatorial computer.

[Summary of the invention]

The present invention detects the position of a coordinate indicator with respect to a group of electrode lines provided on a tablet, and uses the detected position to keep the guidance signal generated between the tablet and the coordinate indicator constant regardless of the position of the coordinate indicator. Based on the magnitude of this corrected value, it is determined whether or not to calculate the coordinates, and the reading height of the coordinate indicator on the tablet is kept constant.

(Prior Art) Conventional coordinate input devices include Japanese Patent Laid-Open No. 138124/1982 and Japanese Patent Laid-Open No. 99683/1989 invented by the present applicant.

These coordinate input devices sequentially detect the induced voltage induced in the electrode wire group arranged on the tablet by the alternating magnetic field generated by the indicator 15, and when the maximum value of this induced voltage is equal to or higher than a predetermined threshold, The coordinates are calculated by comparing the induced voltages of each electrode wire.

[Problem to be solved by the invention]

However, with this conventional coordinate input device, even if the distance between the coordinate indicator 2 blade and the tablet having the electrode wire group is the same,
The maximum value of the induced voltage induced in the electrode wires differs depending on the position of the coordinate indicator, and whether or not to calculate the seat charge based on the induced voltage is determined only by the maximum value of the induced voltage, so the table left The reading height of the coordinate indicator differs depending on the position at which the coordinate indicator is pointed. For example, when using a coordinate input device that requires a particularly low reading height, such as when used in mouse mode, the difference is noticeable and becomes very large. It was difficult to use.

The object of the present invention is to improve upon such conventional drawbacks, and to provide a coordinate input device that allows a coordinate indicator to be read with a constant accuracy no matter where it is placed on the tablet, and that is easy to operate for the operator. There is a particular thing.

[Means to solve the problem]

In order to solve the conventional problems, the present invention includes a detection means for detecting a guidance signal generated by coupling between a tablet and a coordinate indicator, and a first detection means for determining the magnitude of the detected guidance signal.
, a position specifying means for specifying the position of the coordinate indicator based on the position of the coordinate indicator, and a position specifying means for correcting the iM A'I signal based on the determined position. ,
The configuration includes second threshold value determining means for determining the magnitude of this corrected value.

[Effect]

That is, the first threshold value determining means determines whether the maximum value of lead No. 13 detected by the detecting means is larger than a preset threshold. The position of the coordinate indicator is specified by comparing the numbers.The guidance signal correction means corrects the maximum value of the guidance signal based on the specified position so that it is constant regardless of the position of the coordinate indicator.Second The threshold value determination means determines whether or not this corrected value is larger than a preset threshold value, and if it is larger, the coordinates are finally calculated.

Therefore, since the second threshold value determining means determines whether or not to calculate coordinates, it is possible to provide a coordinate input device in which the reading height of the coordinate indicator is constant on the tablet.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 1 to 5. FIG. 1 shows a block diagram of an electric coordinate input device. In FIG. 1, reference numeral 1 denotes a tablet having two sets of conductor electrode wire groups X, .about.xn+ Y.sup.+ .about.Ya. 2 is m
It is connected to the drive circuit 3 by a coordinate indicator having a 5Fa coil (not shown). Scanning circuit 4. ．． 4. is the electrode line group x1 according to the scanning address 6 given from the control circuit 5.
~Xn+7+"")'a are sequentially scanned, and the minute signals induced therein are input to the detection circuit 7. The detection circuit 7 is a circuit that filters, amplifies, and detects the input 4-signal, and is connected to the control circuit 5. Although the internal configuration of the control circuit 5 is not shown, it is a general CPU circuit including an A/D converter, and uses a random access memory to perform predetermined data according to a program written in a read-on memory by a microprocessor. Execute processing. 53-5C is the control circuit 5
The details will be described later.

Next, the operation of this embodiment will be explained. In FIG. 1, the alternating C4l field generated by the coordinate indicator 2 is scanned by a group of electrode lines x1""x which are sequentially selected by scanning circuits 4X and 4y.
For example, when the coordinate indicator 2 is located at the point He and the point B at a certain reading height on the tablet i, the detection circuit 7 Guidance signal 8 of the electrode lines x1 to X to be output
becomes like the prisoner shown in Figure 2, ■.

Then, the control circuit 5 converts the guidance signal 8 into D/D conversion and performs the following processing. That is, FIG. 3 shows a flowchart of the processing in the control n circuit 5, in which the digitalized guidance signal 8 is first determined by the first threshold determination section 5a, where the maximum value V of the guidance signal is set to a certain threshold value {circle around (2)}. , □, and if it is, the position specifying unit 5b performs the following calculation.

V, -V.

V, -V.

V,, V, are the induced signals of the electrode wires with both sides open, where the maximum value of the induced signal, ■, was detected, and the larger value is defined as V. In Fig. 1, at a certain height of the coordinate indicator 2,
When moving from point to point B, Q and the maximum value V of the induced signal shown in the above equation change as shown in FIGS. 4 and 5.

Therefore, by writing the relationship shown in FIG. 4 in advance as jTJ, the relative position on the electrode line can be specified by finding the Q of the old type -1.

Next, in the guidance signal correction section 5c, the maximum value V of guidance No. 13 is
A correction value V shown in FIG. 5 is added to . The correction value V is the fifth
This shows the size of the shaded area in the figure, and by adding to ■, the added values ■ and ′ are made constant. A second threshold value determination section 5d determines whether these values 2 and 2 are larger than a certain threshold value V phi 2, and if it is larger, a coordinate calculation section 5e calculates absolute coordinates from Q determined by the position specifying section 5b.

To explain each threshold value in more detail, when setting the coordinate indicator 2 to a certain reading height, in FIG.
, may be set as the threshold value Vt1I+ of the first threshold value determination section, and Vl'A may be set as the threshold value V Tl+2 of the second threshold value determination section.

In addition, the guidance signal correction unit 5c of this embodiment added the correction value ■, but the value obtained by subtracting the correction value ■ (indicating the size of the diagonal and lined portion) shown in FIG. 6 from V. ■, ′ may also be calculated. At this time, the threshold value VTH of the first and second threshold value determination sections
Both I and V TH2 may be shifted to ▪ in FIG. 2.

FIG. 7 is a block diagram showing another embodiment of the present invention. The difference from the embodiment shown in FIG.
This point is that it is connected to jlfe7.

Next, the operation will be explained. The electrode line group arranged in the tableno)l is scanned by the scanning address 6 outputted from the control circuit 5.
A scanning circuit 4x controlled by.

4y and excited by the drive circuit 3.

The coordinate indicator 2 has a built-in detection coil (not shown), and when each electrode wire is excited, the induction signal induced in the detection coil is input to the detection circuit 7, and the waveform-shaped induction signal 8 is sent to the control circuit 5. input.

In this embodiment as well, the waveform of the induction signal 8 output from the detection circuit 7 is the same as that in the embodiment shown in FIG.
The operation of the ff11 circuit 5 is also the same, so a description thereof will be omitted.

Although the above two embodiments have been described, it goes without saying that the present invention is applicable not only to the electromagnetic induction method described in the embodiments but also to various detection methods, such as an electrostatic induction method.

〔Effect of the invention〕

As explained above, according to the present invention, by providing the first threshold determination section, the position specifying section, the guidance signal correction section, and the second threshold determination section, a constant reading height can be achieved at any location on the tablet. This can be achieved especially with a shuttle input device where a low reading height is used, e.g. when used as a mouse mode (outputs relative coordinates when within the reading height and outputs coordinates when above the reading height). do not)
It is effective when used as an input device for character recognition (- character delimiters are read and recognized using data of a height or higher).

[Brief explanation of the drawing]

3 is a flowchart of the present invention, FIG. 4 is an explanatory diagram of characteristics in the position specifying section, FIG. 5 is an explanatory diagram of characteristics in the guidance signal correction section, and FIG. 6 is a diagram of the characteristics in the guidance signal correction section. FIG. 7 is a block diagram showing another embodiment. l...Tablet 2...Coordinate indicator 3...Drive circuits 4X, 4y...Scanning circuit 5...Control circuits 5a, 5d...Threshold determination section 5b...・Position specifying section 5C... Guidance signal correction section 5e... Coordinate calculation section 6... Scanning address 7... Detection circuit 8... Induction J3 (, No. 1 x 1 ~ xn + y + ~ y, ... Electrode wire group or more Applicant: Seiko Electronics Industries Co., Ltd.

Claims (1)

[Claims] A tablet having two sets of conductor electrode wires arranged at right angles, a coordinate indicator electrically or magnetically coupled to the tablet, and a guiding signal induced by the coupling between the tablet and the coordinate indicator. a coordinate input device having a detection means for detecting, a first threshold value determination means for determining the maximum value of the guidance signal detected by the detection means; and a position determination means for determining the position of the coordinate indicator based on the guidance signal. a guiding signal correcting means for correcting the maximum value of the guiding signal based on the position specified by the position specifying means; and a second threshold determining means for determining the magnitude of the value corrected by the guiding signal correcting means. A coordinate input device comprising: