JPH062441U - Digitizer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a digitizer that can give additional information without impairing the operability when using a pen-type position indicator [Configuration] Induction voltage generated in a conductor grid A level detecting means for detecting the level, an A / D converter for converting the voltage level detected by the level detecting means into a digital value, and a processing means for performing a predetermined process based on the output of the A / D converter. Prepare for digitizer.

Description

[Detailed description of the device]

[0001]

[Industrial technical field]

 The present invention relates to a so-called digitizer, which is a device that includes a tablet and a position indicator to obtain coordinate information of the position indicated by the position indicator on the tablet surface, and is particularly a cordless device that does not require a connecting cord between the tablet and the position indicator. This is for the system type.

[0002]

[Prior art]

 A conventional device in this type of digitizer will be described with reference to FIGS. First, the configuration of the digitizer will be described with reference to FIG. The digitizer includes a position indicator 1 in which a tuning circuit including an indicator coil 11, a capacitor 12 and a switch 13 is formed, a transmitter coil group 21, a receiver coil group 22, a transmitter circuit 211, a sense circuit 221, a processing circuit 23 and a detector. It is composed of a tablet 2 composed of 24. First, based on an instruction from the processing circuit 23, the transmission circuit 211 sends out a current to the transmission coil group 21 at a predetermined timing. Due to this current, a magnetic field is generated around the transmitting coil group 21. When this magnetic field reaches the position where the position indicator 1 is positioned, the magnetic field and the above-mentioned indicator coil 11 are magnetically coupled to each other to generate a current in the tuning circuit. Induce. The current induced in the tuning circuit further generates a magnetic field around the indicating coil 11 and magnetically couples to the receiving coil 22. As a result, a voltage is induced in the sense coil at the position where the position indicator 1 is located.

Now, consider the case where the position indicator 1 is placed on the tablet 2. When the receiving coil located at the center of the indicating coil 11 is n and the loop coils in the vicinity thereof are n ± 1, n ± 2 ... from the near side, the distribution of the induced voltage appearing at the end of the sense coil is shown in FIG. As shown in FIG. 5, the voltage en induced in the receiving coil n is the highest, and then the values en + 1 and en-1, en + 2 and en-2 gradually decrease with distance from the mounting position. The processing circuit 23 calculates the designated coordinates of the position indicator 1 based on this distribution. In this calculation, the rough position is calculated by the receiving coil n to which the maximum induced voltage en is given, and the distance from the receiving coil n, that is, the detailed distance is calculated by the ratio of the voltage values of the adjacent receiving coils n ± 1. It is a thing.

In the above-mentioned conventional device, the additional information such as the line width is provided by the switch mechanism provided in the position indicator 1. This switch mechanism switches and connects a plurality of capacitors, each having a different capacitance, and makes the tuning frequency of the tuning circuit arranged in the position indicator variable. The identification of the additional information in this conventional device is performed by sequentially supplying currents of different frequencies to the oscillator coil group from the drive circuit at a predetermined timing, and the frequency of the induction voltage after passing through the position indicator 1. It was done by detecting.

[0005]

[Problems to be solved by the device]

 When the above switch mechanism is used for a pen-type position indicator, the arranging position of the switch part is limited to the cylindrical part of the housing, so that the operability is impaired when a plurality of switches are mounted. There was such a problem.

The present invention has been made to solve this problem, and its purpose is to be able to provide additional information without impairing its operability even when using a pen-type position indicator. To provide a digitizer.

[0007]

[Means for Solving the Problems]

 Therefore, the digitizer of the present invention comprises a level detecting means for detecting the level of the induced voltage generated in the conductor grid, an A / D converter for converting the voltage level detected by the level detecting means into a digital value, and And a processing means for performing a predetermined process based on the output of the A / D converter.

[0007]

[Action]

 The additional information is determined by the degree of coupling between the grid line group and the position indicator, in other words, the voltage value of the induction voltage. That is, since the additional information can be selected according to the positioning height of the position indicator, the number of switches can be reduced.

[0008]

【Example】

 1 and 2 are views for explaining the present invention, FIG. 1 is a view for explaining a device configuration of the present invention, and FIG. 2 is a view for showing a relationship between a positioning height of a position indicator and an induced voltage.

First, the configuration of the embodiment apparatus will be described. In FIG. 1, the same parts as those shown above are indicated by the same reference numerals. In the figure, reference numeral 24 is a detection unit, which includes a peak voltage detection circuit 241, an A / D (analog / digital) conversion circuit 242, a comparison detection unit 243, and a reference table 244. The other mechanism and operation are the same as those of the conventional device described above, and therefore the description thereof is omitted here to avoid duplication.

In the device of the embodiment, the detection unit 24 is arranged between the sense circuit 221 and the processing circuit 23. In the detection unit 24, the peak voltage detection circuit 241 detects the maximum voltage value for the output signal from the sense circuit 221, and the maximum voltage value is digitally converted by the A / D conversion circuit 242 and then compared and detected. The section 243 compares the data in the reference table 244 to detect additional information.

Here, the reference table 244 will be described. FIG. 2 is a diagram showing the relationship between the positioning distance of the position indicator 1 with respect to the tablet 2 in the height direction and the induced voltage value. As shown in this figure, there is a specific relationship between the height of the position indicator 1 and the induced voltage. The induced voltage has the highest value when the position indicator 1 is closest to the tablet 2, and the value of the induced voltage decreases exponentially as it moves away from the tablet 2.

Therefore, the induced voltage value is divided into e1, e2, and e3, e1 to e2 are set as the first information range, e2 to e3 are set as the second information range, and e3 to are set as the third information range. It is understood that the information can be selected according to the positioning distance of the position pointing device 1 by storing it in the reference table 244. That is, if the distance giving the induced voltage e1 is l1, the distance giving e2 is l2, and the distance giving e3 is l3, if the position indicator 1 is in the range of l1 to l2, the above first information is stored. , L2 to l3, the second information can be selected, and if the distance is more than l3, the third information can be selected. For example, line width and color data are assigned to the first to third information. Also, if the number of divisions is increased and the distance from the tablet surface is transmitted as additional information, three-dimensional data can be input.

In the above description, the position indicator 1 is separated to select information, but the indicating coil 11 may be moved up and down.

[0014]

[Effect of device]

 As described above, according to the digitizer of the present invention, the maximum voltage value of the induced voltage is identified in the tablet, and the additional information is determined based on the maximum voltage value. It has the advantage that the number can be reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing a configuration of the present invention.

FIG. 2 is a diagram for explaining the operation of the present invention.

FIG. 3 is a configuration diagram illustrating a conventional device.

FIG. 4 is an explanatory diagram showing a distribution of induced voltage.

[Explanation of symbols]

 1 Position Indicator 11 Pointing Coil 2 Tablet 221 Sense Circuit 23 Processing Circuit 24 Detection Unit 241 Peak Voltage Detection Circuit 242 A / D Detection Circuit 243 Comparison Detection Unit 244 Reference Table

Claims (1)

[Reference number] G1224 [Claims for utility model registration] 1. A digitizer having a conductor grid in which a voltage corresponding to a position indicated by the position indicator is induced by an electromagnetic field generated by the position indicator, and the level of the induced voltage generated in the conductor grid is detected. A digitizer comprising level detection means, an A / D converter for converting the voltage level detected by the level detection means into a digital value, and processing means for performing a predetermined process based on the output of the A / D converter.