JPH0611031U - Cordless digitizer - Google Patents

Abstract

(57) [Abstract] [Purpose] To provide a cordless digitizer capable of providing a large number of switches on a position indicator. [Structure] A position indicator is composed of a coil, a capacitor and a switch, and a plurality of loop coils insulated from each other are arranged on the tablet in the X-axis direction and the Y-axis direction. An oscillator for driving the axis loop coil group and a changeover switch for changing and connecting the amplifier and the oscillator are provided, and when the approximate position of the position indicator is determined, the changeover switch is changed over to the oscillator and connected to drive the Y axis loop coil. The approximate position of the position indicator is detected by detecting the signal excited by the axial loop coil, and when the precise position is detected and the position of the position indicator is detected, the changeover switch is switched and connected to an amplifier to A self-oscillation system is formed by the coil and position indicator, and the voltage of the signal output from this self-oscillation system and It is configured to detect the precise position of the position indicator and the switch operating state by the frequency.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a digitizer for detecting the position coordinates and the like of a position indicator mounted on a tablet, and more specifically, a so-called cordless digitizer in which the position indicator for indicating the position is not connected to the tablet body. It is about.

[0002]

[Prior art]

 In the conventional cordless digitizer of this type, on the tablet side, for example, a transmitting coil group arranged in the X direction, a receiving coil group arranged so as to be orthogonal to the transmitting coil group, and a drive for driving the receiving coil group. It has a circuit, a sense circuit for detecting the voltage induced in the receiving coil, and a processing circuit for processing the detection output of the sense circuit. Then, the processing circuit controls the drive circuit to sequentially supply the current to the transmitting coil group, and when the position indicator is placed on the tablet, the current-supplied transmitting coil and the position indicator are arranged. And are electromagnetically coupled, and as a result, an induced conductive pressure is generated on the receiving coil group side. The generated induced voltage is detected by the sequential scanning of the sense circuit, and as a result, the processing circuit detects the position on the tablet from the X direction position of the transmitting coil to which the current is supplied and the Y direction position of the receiving coil to which the voltage is induced. Recognize the plane position of the indicator.

FIG. 3 is a configuration diagram of the above-mentioned position indicator, and this position indicator 1 is composed of a coil portion including a coil 11 and a main body portion including a switch group and a resistor group. Then, as shown in FIG. 3B, the coil portion is covered on both sides with an acrylic member which is an insulating member. The position indicator 1 has different resistances connected in series with each switch, and when the switch is opened and closed, the voltage level induced in the receiving coil on the tablet side by the difference in these resistances. Therefore, the processing circuit recognizes the switch depression information of the position indicator. That is, when such a position indicator is placed on the tablet and none of the switches in the switch group is closed, the position detection as described above is performed and the position of the position indicator is detected. When one of the switches in the switch group is closed, a corresponding level of induced voltage is generated in the receiving coil on the tablet side. As a result, the processing circuit recognizes which switch of the position indicator has been operated. .

Further, in the conventional device, when detecting the position of the position indicator, first, the rough position of the position indicator is determined, and then the precise position of the position indicator is determined, and at the same time, the switch pressing state of the position indicator is determined. Was recognizing. As a rough position detection operation, the coils of the transmitter coil group are sequentially driven and driven at predetermined intervals, and at the same time, the voltage induced in the receiver coil is detected, and the transmitter coil and receiver coil are determined when the maximum voltage is detected. . The position indicator is placed on the area formed by these two coils overlapping, and the approximate position of the position indicator is determined by determining this area.

After determining the approximate position of the position indicator, that is, the area on which the position indicator is mounted, the processing circuit detects the maximum voltage and drives the drive coil and the two adjacent coils. At the same time as selecting the driving coil, the receiving coil that has received the maximum voltage and the two receiving coils adjacent to it are selected, and when the three driving coils are sequentially driven, the signals output from the three receiving coils are detected. By comparing the voltage values induced in each area with each other, it is possible to calculate which position in the area determined by the rough position detection operation the position indicator is placed on. In addition, it is configured to detect the pressing state of the switch of the position indicator from the maximum level of the voltage detected at the same time.

Further, as an actual operation of the device, after detecting a rough position of the position indicator, precision position detection and switch state detection are repeatedly performed at a predetermined cycle, and the position indicator is detected during the precision position detection operation. If it does not exist, that is, if it is detected that the position indicator has moved outside the determined area, the rough position detection operation of the position indicator is performed.

[0007]

[Problems to be solved by the device]

 In the above conventional device, the switch state of the position indicator is detected by detecting the voltage level of the signal output from the receiving coil. Therefore, as a practical product, only about four switches are practically used. It has the drawback that it cannot be installed and the number of switches cannot be increased. The present invention has been made to solve the above drawbacks, and an object of the present invention is to provide a cordless digitizer that can be provided with a large number of switches.

[0008]

[Means for Solving the Problems]

 In order to solve the above problems, in the cordless digitizer of the present invention, the position indicator is composed of a coil, a capacitor and a switch, and the tablet has a plurality of mutually insulated loop coils in the X-axis direction and the Y-axis direction. Two loop coil groups aligned with each other, a first amplifier for amplifying a signal input to the Y-axis loop coil group, a second amplifier for amplifying a signal output from the X-axis loop coil group, a plurality of Y-axis An X-axis scanner for selecting one loop coil from the loop coils and connecting it to the first amplifier, a Y-axis scanner for selecting one loop coil from a plurality of Y-axis loop coils and connecting it to the second amplifier, An oscillator for driving the Y-axis loop coil group, a second amplifier, and a changeover switch for changing and connecting the oscillator to the second amplifier are provided. At the time of determination, the changeover switch is switched and connected to the oscillator to drive the Y-axis loop coil, the signal excited by the X-axis loop coil is detected, the approximate position of the position indicator is detected from the induced voltage, and the precise position is detected. When detecting and detecting the state of the position indicator, the changeover switch is connected to the first amplifier by switching, and the precise position and the switch state of the position indicator are determined by the voltage and frequency of the signal output from the first amplifier. Configured to detect.

[0009]

[Action]

 When detecting the approximate position of the position indicator, connect the oscillator and the Y-axis loop coil group by the changeover switch to drive this Y-axis loop coil group and detect the signal excited by the X-axis loop coil group. When the approximate position of the position indicator is detected and the precise position of the position indicator and the switch state of the position indicator are detected, the changeover switch connects the X-axis loop coil group and the Y-axis loop coil group through an amplifier. Then, a self-oscillation system is formed by the electric circuit of the position indicator, the amplifier and two loop coils connected to the amplifier, and the precise position and the switch state of the position indicator are detected based on the output of the amplifier. .

[0010]

【Example】

 The cordless digitizer of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram showing the structure of a tablet of a cordless digitizer of the present invention. In the tablet 20, X-axis loop coil groups X1, X2, which are formed on a grit plate and are sequentially insulated from each other in the X direction, are sequentially arranged. , Xn and Y-axis loop coil groups Y1, Y2, Y3, ..., which are formed on a grid plate different from the X-axis loop coil group and which are sequentially insulated from each other in the Y direction. , Yn are provided. The X-axis loop coil group is connected to capacitors C1, C2, C3, ..., Cn having a predetermined capacitance value in each loop coil, and one terminal of each loop coil is The axis scanner 21 and the other terminal are connected to the ground. Further, one terminal of each loop coil of the Y-axis loop coil group is connected to the Y-axis scanner 22, and the other terminal is connected to the ground. Here, the output side of the X-axis scanner 21 is connected to the input side of the first amplifier 23, the input side of the Y-axis scanner is connected to the second amplifier 24, and the changeover switch 26 is connected to the second amplifier 24. The input is switched and connected to the first amplifier 23 or the oscillator 27. Here, the first amplifier 23 is a voltage amplifier that amplifies a signal voltage, and the second amplifier 24 is a current amplifier that amplifies a signal current. Further, the processing circuit 25 controls the changeover switch 26, the X-axis scanner 21 and the Y-axis scanner 22, takes in the output signal of the first amplifier 23, performs various processing based on the detected signal, The position and the state of the indicator 1 are detected.

2 (a), 2 (b) and 2 (b) are block diagrams showing an embodiment of the position indicator used in the cordless digitizer of the present invention. The coil 11, the capacitor 12, the switch 13 and the ferrite are shown in FIG. It is composed of the core 14. In the position indicator of FIG. 2 (a), which is the first embodiment, when one of the switches 13 is closed, the capacitor 12 connected in series is connected to the switch. In the position indicator of the second embodiment shown in FIG. 2B, the capacitor 12 is insulated when the switch 13 is closed, and is connected when the switch 13 is opened. Moreover, FIG. 2C is a cross-sectional view showing a pen-type position indicator having the circuit shown in FIG. 2B.

In the cordless digitizer of the present invention, when detecting the approximate position of the position indicator 1, first, the processing circuit 25 controls the changeover switch 26 to switch and connect the input of the second amplifier 24 to the oscillator 27. At the same time, the Y-axis scanner 22 is controlled to sequentially drive the Y-axis loop coil. Further, the processing circuit 25 simultaneously switches the X-axis scanner 21 sequentially, detects the induced voltage excited in the X-axis loop coil, and receives the output of the first capacitor 23 as data. The processing circuit 25 determines the Y-axis loop coil and the X-axis loop coil that have output the maximum voltage value of the received data, so that the position indicator 1 is formed on which area on the tablet (the loop coils overlap each other). Area) to detect if it is placed on the area. This completes the rough position determination operation of the position indicator.

After determining the general position of the position indicator, the processing circuit 25 switches the changeover switch 26 to the output side of the first amplifier 23. Further, the processing circuit 25 controls the Y-axis scanner 22 so as to sequentially switch and connect the Y-axis loop coil determined by the above-mentioned rough position determination operation and the adjacent two loop coils, and at the same time, regarding the X-axis loop coil. The X-axis scanner 21 is controlled so as to sequentially switch and connect the X-axis loop coil determined in the rough position determination operation and the two adjacent loop coils. When the Y-axis loop coil and the X-axis loop coil immediately below the position indicator 1 are selected and connected, the Y-axis loop coil, the position indicator coil 11, the X-axis loop coil, and the parallel thereto A self-oscillation system is formed by the capacitor, the first amplifier, and the second amplifier connected to, and the signal generated by the self-oscillation system is transmitted to the processing circuit 25. The processing circuit 25 controls the X-axis scanner 21 and the Y-axis scanner 22, and controls the voltage value of the signal output from each self-oscillation system formed when the selected loop coils are connected. By comparing them with each other, it is detected at which position in the area specified by the rough position determining operation the position indicator 1 is placed. (Precision position determination operation)

Further, when the switch of the position indicator 1 is operated to connect the capacitor and the coil, the frequency of the signal transmitted from the output of the second amplifier 24 to the processing circuit 25 changes to the X-axis loop coil. By changing the frequency depending on the capacity of the capacitor Cn connected in parallel from the frequency depending on the capacity of the capacitor 12 of the position indicator 1, and detecting the frequency of the signal transmitted to the processing circuit 25, The state of the switch of the position indicator can be detected. (Switch state detection operation)

In the case of the position indicator shown in FIG. 2 (a), the capacitors 121, 122, ..., 12n have different capacities, and the frequency of the signal transmitted to the processing circuit 25 is the capacity of the capacitor. It is configured to detect which switch of the position indicator 1 is pressed by detecting whether the switch depends on the position. Further, in the case of the position indicator shown in FIG. 2 (c) having the electric circuit of FIG. 2 (b), the switch 13 is opened when the tip portion of the core body of the position indicator is grounded on the tablet surface, and the core is The capacitance value of the variable capacitor 12 is configured to continuously change as the body moves. Therefore, by detecting the frequency of the signal transmitted to the processing circuit 25, it is possible to detect whether or not the position indicator 1 is grounded on the tablet, or the pressing force of the position indicator on the tablet.

[0016]

[Effect of device]

 As described above in detail, according to the present invention, the Y-axis loop coil is driven by the oscillator at the time of detecting the approximate position of the position indicator, and the signal excited by the X-axis loop coil via the magnetic substance or coil of the position indicator. When detecting the precise position of the position indicator or the position of the position indicator, the output of the first amplifier is set to the second The voltage value of the signal output from the voltage amplifier is formed by connecting to the input of the amplifier to form a self-oscillation system consisting of the Y-axis loop coil, position indicator, X-axis loop coil, first amplifier, and second amplifier. Since it is configured to detect the precise position of the position indicator and the switch state of the position indicator from the frequency of the signal output from the current amplifier, the state detection of the position indicator is not affected by the voltage value. It can be performed reliably by the wave number, the desired number of switches of the position indicator can be installed, and the state change of the switch of the position indicator can be continuously detected. Produce an effect.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a cordless digitizer according to the present invention.

FIG. 2 is an explanatory view showing a position indicator of the cordless digitizer of the present invention.

FIG. 3 is an explanatory view showing a conventional position indicator.

[Explanation of symbols]

 1 Position Indicator 11 Coil 12 Capacitor 13 Switch 14 Magnetic Material 2 Tablet 21 X Axis Scanner 22 Y Axis Scanner 23 First Amplifier 24 Second Amplifier 25 Processing Circuit 26 Changeover Switch 27 Oscillator

Claims (1)

[Scope of utility model registration request] 1. A first coil group arranged in a first direction, and a second coil group arranged in a second direction orthogonal to the first direction and having capacitors connected in parallel for each unit coil pattern. A tablet including a coil group, an oscillator, and an amplifier, an electric circuit having at least a coil and a capacitor, and the tablet having a switch for enabling or disabling the capacitor with respect to the coil and a wireless device. A cordless digitizer for detecting a pointed position and the like of the position pointer mounted on the tablet, wherein the first coil group of the tablet is connected to the oscillator or the second position indicator. It has a switching means for switching and connecting to the output side of the coil group, and when the general position indicated by the position indicator is detected, the switching is performed. Means for connecting the first coil group to the oscillator to drive the first coil group, and detecting the signal induced in the second coil group to detect the general position of the position indicator. However, when the precise position indicated by the position indicator and the switch state of the position indicator are detected, the first means is operated by the switching means.
Connect the coil group of No. 2 to the second coil group through the amplifier,
An electric circuit of the position indicator, the amplifier, and two coil patterns connected to the amplifier form a self-oscillation system, and the precise position and the switch state of the position indicator are detected based on the output of the amplifier. A cordless digitizer characterized by doing so.