JPH0235512A - Position indicator - Google Patents

Abstract

PURPOSE:To increase the amount of information to be sent by providing a 1st tuning circuit which increases in tuning frequency from a specific frequency according to a pen stroke force and a 2nd tuning frequency which has a low tuning frequency to one end of a rod type housing. CONSTITUTION:A coordinate input device which uses the position indicator (input pen) 10 consists of a tablet 20, a position detecting circuit 30, a data processor 40, and a display device 50. This input pen 10 is equipped with the rod type housing 11, the 1st tuning circuit 12 provided to one end 11a of the housing, and the 2nd tuning circuit 13 provided to the other end 11b. This tuning circuit 12 consists of a core body 121 equipped with a ferrite chip 121a, a coil 122, a core holder 123, a support spring 124, and a capacitor 125 and the tuning circuit 13 is also constituted similarly. The coils 122 and 132 and capacitors 125 and 135 form resonance circuits and the tuning frequency of the tuning circuit 13 increases with the pen stroke force. Consequently, one end is used as a pen and the other is used as an eraser.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a position indicator of a coordinate input device that detects the position of a tablet by exchanging radio waves with the tablet.

(Prior art) Prior to filing this application, the applicant filed the patent application No. 61-2139.
No. 70 (see Japanese Unexamined Patent Publication No. 63-70326) (hereinafter referred to as
It is called a first application. ) proposed a device that detects the designated position of a position indicator by exchanging radio waves between the tablet and the position indicator.

To briefly explain the content of the earlier application, a signal of a predetermined frequency is applied to the negative loop coil of a tablet in which a large number of loop coils are arranged in parallel in the position detection direction, and radio waves are transmitted from the negative loop coil. Then, the radio waves are received by a tuned circuit including a coil and a capacitor provided in the position indicator, and at this time, the radio waves emitted from the tuned coil of the tuned circuit are transferred to the - loop where the signal supply has been stopped. By causing the coil to receive the induced voltage, an induced voltage is generated in the negative loop coil, and this is repeated for all of the large number of loop coils, so that the voltage value is the maximum among the large number of induced voltages generated in each loop coil. This is to detect the specified position of the position indicator.

(Problems to be Solved by the Invention) The device does not require a wire between the position indicator and other parts. Further, although there are advantages such as the position indicator does not require a power source, there is a problem in that there is little information other than position information that can be transmitted from the position indicator to other parts.

The present invention provides a position indicator that does not require a signal line between it and other parts and does not require a power source, and can greatly increase the amount of information that can be transmitted to other parts. The purpose is to

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a first method that includes at least a coil and a capacitor, and whose tuning frequency changes higher (or lower) than a predetermined frequency according to pen pressure. A position indicator including a tuning circuit and a second tuning circuit including at least a coil and a capacitor and having a tuning frequency lower (or higher) than a predetermined frequency, respectively provided at both ends of a rod-shaped housing; Contains a capacitor, and the tuning frequency is higher (or lower) than the predetermined frequency depending on the pen pressure
A first tuning circuit that changes in the direction of the predetermined frequency and a second tuning circuit that includes at least a coil and a capacitor and whose tuning frequency changes toward lower (or higher) than a predetermined frequency according to the pen pressure are housed in a rod-shaped casing. We propose a position indicator installed at each end of the body.

(Function) According to the present invention, when one end of the casing of the position indicator is used on a tablet and used, the radio waves emitted from the tablet are received by the two tuned circuits of the position indicator. However, compared to the tuning circuit installed at one end, the tuning circuit installed at the other end is farther away from the tablet, so the received radio waves are weaker, and the emitted radio waves are also weaker. Only the designated position based on the circuit will be detected, and in this case, if the tuning circuit provided at one end is the first tuning circuit, the tuning frequency will be higher than the predetermined frequency according to the pen pressure. (or lower), this causes the tuning circuit in use on the processing device side to
If the tuning circuit provided at one end is the second tuning circuit, the tuning circuit is recognized as being a tuning circuit of Since it is low (or high), this confirms that the tuning circuit in use on the processing device side is the second tuning circuit.

Further, according to the present invention, if the tuning circuit provided at one end is the first tuning circuit, the tuning frequency changes higher (or lower) than a predetermined frequency according to the writing pressure.
As a result, the processing device side recognizes that the tuning circuit in use is the first tuning circuit, and the information corresponding to the pen pressure is extracted, and the tuning circuit provided at one end becomes the second tuning circuit. In the case of the same week circuit, the tuning frequency changes to lower (or higher) depending on the pen pressure compared to the predetermined frequency, so this causes the tuning circuit in use on the processing device side to switch to the second tuning frequency. It is recognized that it is a circuit, and information corresponding to the writing pressure is extracted.

(Embodiment) FIG. 1 shows an embodiment of the position indicator of the present invention.
In the figure, 11 is a rod-shaped casing made of a non-metallic material such as synthetic resin, 12 is a first tuning circuit provided at one end 11a of the casing 11, and 13 is a first tuning circuit provided at the other end 11b of the casing 11. This is the second tuned circuit.

The tuning circuit 12 includes a core body 121 provided with a ferrite chip 12La, a coil 122 that can slidably accommodate the core body 121 therein, a core holder 123 that holds the rear end of the core body 121, and a core holder 123. a spring 124 that supports the capacitor 125 so as to be slightly displaceable relative to the housing 11; and a capacitor 125.
It consists of Further, the tuning circuit 13 includes a core body 131 having a ferrite chip 131a, a coil 132 that can slidably accommodate the core body 131, and a core body 131.
a lead holder 133 that holds the rear end of the lead holder 13;
3 and a capacitor 135. Also,
A cap 14 is provided at the tip of the core body 131.

As shown in FIG. 2, the coil 122 and capacitor 125 are connected in series to form a well-known resonant (tuned) circuit, and the values of the coil 122 and capacitor 125 are set at a predetermined frequency of 10. The voltage and current phases are set to values that resonate in the same phase. Here, when the core body 121 is held by the core holder 123, the ferrite chip 121a is located at the lower end of the coil 122, and when it comes into contact with a tablet, etc., which will be described later, the current brush Depending on the pressure, the core ■21,
That is, the ferrite chip 121a moves, thereby increasing the inductance of the coil 122, and the tuning frequency in the above-mentioned tuning circuit 12 changes slightly to the lower side.

Further, the coil 132 and the capacitor 135 are connected in series with each other as shown in FIG. At frequency fO, the phases of the voltage and current are set to a value that resonates in the same phase. Here, in a state where the core body 131 is held by the core holder 133, the ferrite chip 131a is attached to the coil 132.
It is located at the lower end (upper end when in use), and when it comes into contact with a tablet, etc. (described later), the core body 131, that is, the ferrite chip 131
a moves, thereby the inductance of the coil 132 becomes smaller, and the tuning frequency applied to the above-mentioned tuning circuit 13 changes to a slightly higher side.

FIG. 2 shows the above-mentioned position indicator (hereinafter referred to as input pen).

) 10, in which 20 is a tablet, 30 is a position detection circuit, 40 is a data processing device, and 50 is a display device.

FIG. 3 shows details of the X-direction loop coil group 21 and the Y-direction loop coil group 22 that constitute the tablet 20. The loop coil group 21 in the X direction includes a large number of loop coils arranged parallel to each other and overlapping each other along the X direction.
For example, 48 loop coils 21-1, 21-2.・
...21-48, and the loop coil group 22 in the Y direction includes a large number of loop coils 22-1, 22-2, which are arranged parallel to each other and overlapping each other along the Y direction. ．． ...22-48, and the loop coil group 21 in the X direction and the loop coil group 22 in the Y direction are closely overlapped with each other (however, in the drawing, they are separated for ease of understanding). ),
Furthermore, it is housed in a case (not shown) made of a non-metallic material. Although each loop coil is configured with one turn here, it may be configured with multiple turns as necessary.

FIG. 4 shows details of the position detection circuit 30 as well as the tuning circuit 1213 of the input pen 10 described above.
1 is a control circuit, 302 is a signal generation circuit, 303, 30
4 is a selection circuit; 305 and 306 are transmission/reception switching circuits; 30
7 and 308 are drive circuits; 309 and 310 are amplifiers;
311 is an XY switching circuit, 312 is a reception timing switching circuit, 313 is a bandpass filter, 314 is a detector, 315°, 316 is a phase detector (PSD), 317, 31
8 and 31.9 are low pass filters (LPF).

Next, the operation of the device will be explained along with its configuration.
First, the manner in which radio waves are transmitted and received between the input pen 10 and the tablet 20 and the signals obtained at this time will be described with reference to FIG.

The control circuit 301 is composed of a well-known microprocessor, etc., and controls the signal generation circuit 302, and also controls switching of each loop coil of the tablet 20 via selection circuits 303 and 304 according to the flowchart shown in FIG. It also controls the switching of the coordinate detection direction for the XY switching circuit 311 and the reception timing switching circuit 312, and also controls the switching of the coordinate detection direction for the XY switching circuit 311 and the reception timing switching circuit 312.
The output value from 19 is analog-digital (A/D) converted, the arithmetic processing described later is executed to obtain the coordinates specified by the human pen 10, the phase of the received signal is detected, and these are sent to the data processing device 40. Send.

The selection circuit 303 sequentially selects one loop coil from the loop coil group 21 in the X direction, and the selection circuit 304 sequentially selects one loop coil from the loop coil group 22 in the Y direction. Each of them operates according to information from the control circuit 301.

The transmission/reception switching circuit 305 alternately connects the selected negative loop coil in the X direction to the drive circuit 307 and the amplifier 309, and the transmission/reception switching circuit 30B connects the selected negative loop coil in the Y direction to the drive circuit 307 and the amplifier 309. The drive circuit 308
and amplifier 310, and these operate according to a transmission/reception switching signal, which will be described later.

The signal generation circuit 302 has a predetermined frequency fO1, for example, 500.
kHz rectangular wave signal A1 The phase of the rectangular wave signal A is 90''
Delayed signal B, predetermined frequency fk.

For example, a 15.625 kHz transmission/reception switching signal C and a reception timing signal are generated. The rectangular wave signal A is sent as it is to the phase detector 315, is converted into a sine wave signal E by a low-pass filter (not shown), and is further sent to the drive circuit 307 or 308 via the XY switching circuit 311.
Further, the rectangular wave signal B is sent to the phase detector 316, the transmission/reception switching signal C is sent to the transmission/reception switching circuits 305 and 306, and the reception timing signal is sent to the reception timing. The signal is sent to the switching circuit 312.

Now, if information for selecting the X direction is input from the control circuit 301 to the XY switching circuit 311 and the reception timing switching circuit 312, the sine wave signal E is transmitted to the drive circuit 30.
7, is converted into a balanced signal, and is further sent to the transmission/reception switching circuit 805, but the transmission/reception switching circuit 305 switches and connects either the drive circuit 307 or the amplifier 309 based on the transmission/reception switching signal C. Transmission/reception switching circuit 305
The signal output to the selection circuit 303 is the time T (-1
/2 fk), here 500k every 32μsec
This becomes a signal F that outputs or does not output the H2 signal.

The signal F is passed through the selection circuit 303 to the negative loop coil 21-i (i-1, 2,
...48), but the loop coil 2
1-1 generates radio waves based on the signal F.

At this time, when the input pen 10 is held on the tablet 20 in a substantially upright state with one end 11a side close to it, that is, in a use state, the radio wave excites the coil 122, and the tuned circuit 12 receives the above-mentioned signal. An induced voltage G synchronized with F is generated.

At this time, the radio wave also excites the coil 132, and the tuned circuit 13 thereof also generates an induced voltage synchronized with the signal F, but the tuned circuit 13 is connected to the other end 11b side of the housing 11 of the input pen 10. and is far away from the tablet 20, the induced voltage generated in the tuned circuit 13 is far away from the tuned circuit 12.
It is quite small compared to the induced voltage generated in this case, and can be almost ignored.

Thereafter, when the loop coil 21-1 is switched to the amplifier 309 side as the signal F enters a no-signal period, that is, the reception period, the radio wave from the loop coil 21-1 immediately disappears, but the induced voltage G It gradually attenuates depending on the loss within the tuning circuit 12.

On the other hand, the current flowing through the tuned circuit 12 based on the induced voltage G causes the coil 122 to emit radio waves.

The radio waves are transmitted through the loop coil 21- connected to the amplifier 309.
1 is reversely excited, an induced voltage is generated in the loop coil 21-1 by the radio waves from the coil 122. The induced voltage is sent from the transmission/reception switching circuit 305 to the amplifier 309 only during the reception period, is amplified, becomes a reception signal H, and is further sent to the reception timing switching circuit 312.

The reception timing switching circuit 312 receives either the selection information in the X direction or the Y direction, here the selection information in the X direction, and the reception timing signal R which is essentially an inverted signal of the transmission/reception switching signal C. The signal is high (H)
During the level period, the received signal H is output, and during the low (L) level period, nothing is output, so the output is the signal I (
(substantially the same as the received signal H) is obtained.

The signal I is sent to a bandpass filter 313, which is a ceramic filter whose natural frequency is fO.
A signal J having an amplitude corresponding to the energy of the O component (strictly speaking, in a state in which several signals I are input to the bandpass filter 313 and converged) is sent to a detector 314 and phase detectors 315 and 318.

The signal J input to the detector 314 is detected and rectified into a signal, and then passed through a low-pass filter 317 with a sufficiently low cutoff frequency to a voltage value corresponding to approximately 1/2 of the amplitude.
For example, the control circuit 3
01.

The voltage value VW of the signal is a value that depends on the distance between the coil 122 of the first tuned circuit 12 of the input valve 10 and the loop coil 21-1, and here is a value that is approximately inversely proportional to the fourth power of the distance. , changes when the loop coil 21-i is switched. Therefore, in the control circuit 301, the voltage value VX obtained for each loop coil is converted into a digital value, and by performing arithmetic processing to be described later on these values, the input pen 1
The specified coordinates in the X direction by the first tuning circuit 12 of 0 are determined. Further, the coordinates specified in the Y direction by the first tuning circuit 12 of the input pen 10 are obtained in the same manner, and furthermore, the coordinates designated by the second tuning circuit 13 of the input pen 10 are
The specified coordinates in the direction and the Y direction are similarly determined when the other end 11b of the handheld bench 10 is used on the tablet 20 in close proximity to each other.

On the other hand, the rectangular wave signals A and B are manually input to the phase detectors 315 and 316 as detection signals, and at this time, assuming that the phase of the signal J almost matches the phase of the rectangular wave signal A, the phase The detector 315 outputs a signal Ml (substantially the same as the signal) which is the inversion of the signal J to the positive side, and the phase detector 316 outputs a signal M2 having a waveform that is symmetrical on the positive and negative sides. do.

The signal M1 is converted into a DC signal Nl (substantially the same as the signal Nl) having a voltage value corresponding to approximately 1/2 of the amplitude of the signal J, that is, Vx, by a low-pass filter 31B similar to the above, and then passed through the control circuit 301. Also, the signal M2 is converted into a DC signal N2 by a similar low-pass filter 319 and sent to the control circuit 301, but here
Since the positive side and negative side components of the signal M2 are the same, the voltage value of the output of the low-pass filter 319 is 0 [V].

The control circuit 301 converts the output values of the low-pass filters 318 and 319, here the signals NL and N2, into digital values, and further uses these digital values to perform the arithmetic processing of the following equation (1). The phase difference θ between the signal added to signal 316, here J, and the rectangular wave signal A is determined.

θ--tan-' (VQ/VP)
--(1) However, VP is the digital value corresponding to the output of the low-pass filter 318, and VQ is the digital value corresponding to the output of the low-pass filter 318.
The digital value corresponding to the output of No. 19 is shown. For example, in the case of the signal J described above, the voltage value of the signal Nl is VX, but the voltage value of the signal N2 is 0 [V], that is, VQ-0, so the phase difference is θ-0°.

Incidentally, the phase of the signal J changes in accordance with the tuning frequency in the tuning circuit 12 or 13 of the input pen 10.

When the tuning frequency in the tuning circuit 12 or 13 matches the predetermined frequency fO, that is, the core body 131 or 132
When no pen pressure is applied to the received signal H( Or, the frequency and phase of I) will match those of the rectangular wave signal A, and the phase of the signal J will also match those of the rectangular wave signal A.

On the other hand, if the tuned frequency in the tuning circuit 12 does not match the predetermined frequency fO, for example, if it changes to a frequency slightly lower than the frequency fO, for example, fl, the tuning circuit 12 will have an induction of the frequency fO during the signal transmission period. A voltage is generated, but at that time, an induced current with a phase lag flows through the tuned circuit 12. Also, during the signal reception period, an induced voltage of approximately frequency f1 is generated, and an induced current synchronized with this is generated. , the frequency of the received signal H (or I) is slightly lower than the frequency of the rectangular wave signal A, and
The phase is also slightly delayed. As mentioned above, since the bandpass filter 313 has only the frequency fO as its frequency, a shift in the frequency of the input signal toward the lower side is outputted as a phase lag, and therefore, the phase of the signal J is is further delayed than the received signal H (or I).

Conversely, if the tuning frequency in the tuning circuit 13 changes to a frequency slightly higher than the predetermined frequency fO, for example f2, an induced voltage at the frequency fO is generated in the tuning circuit 13 during the signal transmission period; , an induced current with a phase lead flows through the tuning circuit 13, and an induced voltage of approximately frequency f2 is generated during the signal reception period, and an induced current synchronized with this occurs, so that the received signal H The frequency of (or ■) is slightly higher than the frequency of the rectangular wave signal A, and its phase is also slightly advanced. In the bandpass filter 313, the frequency shift toward the higher side of the input signal is output as a phase lead, contrary to the case described above. ) It goes further than slander.

As mentioned above, since the tuning frequency of the tuning circuits 12 and 13 changes according to the writing pressure applied to the input pen 10, the above (
1) The phase difference θ determined by the formula also changes in accordance with the writing pressure, and in this case, if the phase difference θ is negative, the phase is delayed, that is, the coordinate value at that point is the same as that of the first tuned circuit i2. In addition, if the phase difference θ is positive, the phase is advanced, that is, the coordinate value at that point is due to the second tuning circuit 13. This means that it can be determined that the writing pressure is the same, and information regarding the writing pressure can also be extracted.

Actually, the determined position difference θ is transferred to the data processing device 40 together with the coordinate values in the X direction and the X direction, where the above-mentioned judgment is made.

Next, the details of the position detection operation and phase detection operation in the input pen 10, tablet 20, and position detection circuit 30 will be explained according to FIGS. 6 to 9.

First, the control circuit 301 sends information for selecting the X direction to the XY switching circuit 311 and the reception timing switching circuit 312, and also selects the first loop coil among the loop coils 21-1 to 21-48 in the X direction of the tablet 20. 21
-1 is sent to the selection circuit 303, and the loop coil 21-1 is connected to the transmission/reception switching circuit 305.

The transmission/reception switching circuit 305 alternately connects the loop coil 21-1 to the drive circuit 307 and the amplifier 309 based on the transmission/reception switching signal C described above.
sends 16 sine wave signals of 500 kHz as shown in FIG. 7(a) to the loop coil 21-1 during a transmission period of 32 μsec (in FIG. 5, 5 of them are shown for convenience of drawing). ).

The switching between transmission and reception is as shown in FIG. 7(b).
loop coil, here repeated seven times for 21-1. This seven-time transmission and reception repetition period corresponds to the - loop coil selection period (448 μsec).

At this time, an induced voltage is obtained at the output of the amplifier 309 for the - loop coil every seven reception periods, but this induced voltage is transferred to the reception timing switching circuit 311 as described above.
The signal is sent to the bandpass filter 313 via the wave detector 314, the phase detector 315.degree.

The control circuit 301 converts the output value of the low-pass filter 317 into A
/D conversion and input, and temporarily stored as a detected voltage, for example, Vxl, depending on the distance between the tuning circuit of the input pen 10, for example, the 12 coils 122 and the loop coil 21-1.

Next, the control circuit 301 sends information for selecting the loop coil 21-2 to the selection circuit 303, and sends information to select the loop coil 21-2.
2 is connected to the transmission/reception switching circuit 305 to obtain a detection voltage VX2 that depends on the distance between the coil 122 and the loop coil 21-2 and store it.
21-48 are sequentially connected to the transmission/reception switching circuit 305, and the coils 12 for each loop coil are connected as shown in FIG. 7(c).
Detection voltage Vxl-Vx4 depending on the distance in the X direction from 2
8 (however, only a part of it is shown in an analog representation in FIG. 7(C)) is stored in S2.

As shown in FIG. 8, the actual detected voltage is obtained only from several loop coils before and after the position (xp) where the coil 122 is placed as the center.

The control circuit 301 checks whether the voltage value of the stored detection voltage is above a certain detection level, and if it is below the certain detection level, selects each loop coil in the X direction and performs voltage detection again. Repeatedly, if the detection level is above a certain level, proceed to the next process.

Next, the control circuit 301 sends selection information in the Y direction to the XY switching circuit 311 and the reception timing switching circuit 312,
In the same manner as described above, the selection circuit 304 and the transmission/reception switching circuit 30B
The detection voltage is determined depending on the distance between the coil 122 and each of the loop coils 22-1 to 22-48 in the Y direction, which is obtained by A/D converting the output value of the low-pass filter 317 when transmitting and receiving radio waves. Memorize temporarily. After that, perform a level check in the same way as above, and if it is below a certain detection level,
Returning again to selecting each loop coil in the X direction and detecting the voltage, if it is above a certain detection level, the coordinate values of the coil 122 in the X and Y directions are determined from the stored voltage value as described later. Calculate.

Next, the control circuit 301 controls the loop coil 21 in the X direction.
-1 to 21-48 (or Y direction loop coil 22-
1 to 22-48), information for selecting the loop coil (peak coil) from which the maximum detected voltage was obtained is sent to the selection circuit 303 (or 304), and the radio waves are transmitted and received multiple times, for example, 7 times. Repeat, then the low pass filter 31
The output values obtained from 8 and 319 are A/D converted, and the phase difference θ is calculated as described above.

The phase difference θ is transferred to the data processing device 40 together with the coordinate values of the coil 122 in the X and Y directions.

When the first coordinate detection operation and phase detection operation are completed in this manner, the control circuit 301 performs the second and subsequent coordinate detection operations as shown in FIG. 21-48, information for selecting only a certain number of loop coils, for example, 10 loop coils before and after the loop coil where the maximum detected voltage was obtained, is sent to the selection circuit 303, and the loop coil in the Y direction coil 2
Among 2-1 to 22-48, a certain number of loop coils around the loop coil where the maximum detection voltage was obtained, also 1
Information selection circuit 30 for selecting only 0 loop coils
4, obtain the output value in the same manner as described above, and send it to the coil 122.
A coordinate detection operation and a phase detection operation in the X direction and Y direction are performed for the coordinates, and the obtained coordinate values and phase difference are transferred to the data processing device 40, and these steps are repeated hereafter.

Further, coordinate detection operations and phase detection operations in the X and Y directions for other coils 132 of the input pen 10 are performed in the same manner, and the obtained coordinate values and phase differences are transferred to the data processing device 40, which will be described below. is repeated.

To explain the level check mentioned above in detail, it checks whether the maximum value of the detection voltage has reached the detection level and which loop coil has the maximum detection voltage, and then checks whether the maximum value of the detection voltage has reached the detection level. If it has not been reached, subsequent coordinate calculations etc. are stopped, and the center of the loop coil to be selected in the next coordinate detection operation and phase detection operation is set.

As one calculation method for determining the coordinate value in the X direction or the Y direction, for example, the coordinate value xp, the detection voltages Vx1 to V
There is a method of approximating the waveform near the maximum value of X48 by an appropriate function and finding the coordinates of the maximum value of the function.

For example, in FIG. 7(c), the maximum detection voltage Vx3
By approximating the detected voltages Vx2 and VX4 on both sides by a quadratic function, it can be calculated as follows (however, the coordinate values of the center positions of each loop coil 21-1 to 21-48 are x4g, and the interval is ΔX.)
. First, from each voltage and coordinate value, Vx2-a (x2-xp) 2+b -
(2) Vx3-a (x3-xp) 2+b
-(3)Vx4-a (x4-xi3) 2+b
-(4). Here, a and b are constants (a
< 0).

Also, x3-x2 =Δx =-(5)
x4−x2 =2Δx =16). (5), (6) to (3), (4)
Substituting it into the formula and rearranging it, xp = x2 + Δx/2 f (3VX2-4Vx3+
VX4) / (VX2-2VX3+VX4) 1...
・(7) becomes.

Therefore, from each detection voltage V The coordinate value xp of the coil 122 (or 132) can be calculated by performing an operation corresponding to the above-mentioned equation (7) from the coordinate value (known) of the previous loop coil.

FIG. 10 shows details of the data processing device 40. In the figure, 41 is a keyboard, 42 is a read-only memory (R
OM), 43 is random access memory (RAM)
, 44 is a frame memory, 45 is an interface circuit for the position detection circuit 30, 46 is an interface circuit for the display device 50, and 47 is a microprocessor (CPU).

FIG. 11 shows a function for continuously inputting points of different sizes depending on the writing pressure using the input pen 10 (hereinafter referred to as brush pen function) and an area of different sizes depending on the writing pressure. It shows the flow of a program in the data processing device 40 when realizing a continuous erasing function (hereinafter referred to as an eraser function).

Further, FIG. 12 shows the phase angle setting state corresponding to the program. Here, at frequency fO
-5a to -30° is the brush pen approach area, -30'' to 6
0'' is the brush pen input area for inputting a point proportional to the value, 5'' to 30@ is the eraser approach area, and 30'' to 60'' is the area proportional to the value. Use the eraser to erase the area. It is assumed that the phases of the first and second tuning circuits 12 and 13 of the input pen 10 are set to indicate -10 degrees and 10 degrees when no writing pressure is applied.

First, when the input pen 10 approaches the tablet 20 with its one end 11a facing downward, the above-described radio waves are exchanged between the first tuning circuit 12 and the tablet 20, and the position detection circuit 30 The designated position and phase are detected and sent to the data processing device 40.

At this time, when the core 121 of the input pen 10 is not in contact with the tablet 20, the phase in the first tuning circuit 12 is -10'' as described above. When this is detected from the information, a cursor indicating a brush pen, for example "ten", is displayed at a specified position on the display device 50.

When the core body 121 of the human pen 10 is brought into contact with the tablet 20 and the phase difference becomes 130'' or more, the CPU 47
converts the phase information in the received data at that time into spread information of the input point, for example, the diameter of a circle proportional to the phase information, draws an image of a circle having the diameter at a specified position in the frame memory 44, and converts this into It is displayed on the display device 50.

The above process is repeated while data is being transferred from the position detection circuit 30, so when the human pen 10 is moved while changing the pen pressure, a trajectory 6 of the designated position is created as shown in FIG.
Images 61 of circles with different diameters are continuously arranged along 0,
An image similar to that obtained using a brush is obtained. Note that a more natural result can be obtained by performing the process of filling out the inside of the image.

Next, when the input pen 10 is approached on the tablet 2o with the other end 11b facing downward, the above-described exchange of radio waves is performed between the first tuning circuit 13 and the tablet 20, and the position detection circuit The designated position and phase are detected at 30 and sent to the data processing device 40.

At this time, the cap 14 of the input pen 10, that is, the core 13
1 is not in contact with the tablet 20, the phase in the first tuning circuit 13 is 10'' as described above, so when the CPU 47 detects this from the received information regarding the designated position and phase, the display device A cursor indicating an eraser, for example, a "mouth" is displayed at a specified position on the screen 50.

When the cap 14 of the human pen 10 is brought into contact with the tablet 20 and the phase difference becomes 30@ or more, the CPU 47
converts the phase information in the received data at that time into spread information of the erasure area, for example, the diameter of a circle proportional to the phase information,
The inside of a circle having the aforementioned diameter centered at the specified position in the frame memory 44 is erased, and this is displayed on the display device 50.

The above process is repeated while data is being transferred from the position detection circuit 30, so when the input ben 10 is moved while changing the pen pressure, the input ben 10 follows the trajectory of the designated position and has a width corresponding to the pen pressure, as described above. The area is erased.

Further, the data stored in the frame memory 44 is converted into an 11-copy by a printer (not shown) as needed, and is transmitted to another device via a communication line (not shown).

According to the embodiment described above, by simply using the input pen 10 by bringing the one end 11a side into contact with the tablet 20, it is possible to input a brush pen, and the thickness of the input pen 10 can be adjusted according to the pressure of the pen. Eraser can be applied by simply using the other end 11b in contact with the tablet 20, and the size of the erasing area can be adjusted. There is no need to enter a command to indicate its use or to enter a command to indicate its use.

The reason why the phase angle of -5'' to 5° is not used is because the phase of each tuning circuit actually shifts slightly due to temperature changes, etc. Due to this influence, the data processing device 40 is not used when the brush pen approaches and the eraser This is to prevent erroneous recognition that the object is approaching.

Further, in the above embodiment, the first tuning circuit 12 is used for inputting a brush pen, and the second tuning circuit 13 is used for an eraser, but the invention is not limited to this. For example, the tuning circuit 12 is used for inputting handwriting. If the tuning circuit 13 is for manual menu input, there is no possibility of accidentally inputting a menu item provided outside the handwriting input area during handwriting input. Furthermore, if the tuning circuit 12 is used for adjusting the color density and the tuning circuit 13 is used for adjusting the color saturation, coloring in various designs etc. can be performed efficiently.

Further, either one of the tuning circuits 12 or 13 may be configured to always generate constant phase information regardless of the pen pressure, and in this case, a switch that is linked to the core may be provided to The switch may be turned on only when is pressed, forming a tuned circuit.

(Effects of the Invention) As explained above, according to the present invention, a first tuning circuit whose tuning frequency changes to higher (or lower) than a predetermined frequency according to pen pressure is provided at one end of the rod-shaped housing. Since a second tuning circuit having a tuning frequency lower (higher) than the predetermined frequency is provided at the other end, the input pen can be used with either one end or the other end facing the tablet, and the difference can be recognized. As a result, it is possible to provide information for selective use, such as using a pen manually in one case, and applying an eraser in the other case.Moreover, when the first tuning circuit is used, Information can also be given depending on the pressure of the pen. Further, according to the present invention, the first tuning circuit whose tuning frequency changes to higher (or lower) than a predetermined frequency according to the pen pressure is provided at one end of the rod-shaped housing, and the first tuning circuit is provided at the other end according to the pen pressure. Since a second tuning circuit is provided in which the tuning frequency changes to lower (or higher) than the predetermined frequency accordingly, in addition to the above effect, even when the second tuning circuit is used, information according to the pen pressure can be transmitted. There are advantages such as being able to give.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the position indicator of the present invention;
Figure 2 shows a coordinate input device using the position indicator of the present invention.
- A diagram showing an example, Figure 3 is a detailed configuration diagram of the loop coil group in the X direction and Y direction of the tablet, Figure 4 is a diagram showing details of the tuning circuit and position detection circuit of the position indicator, Figure 5 are signal waveform diagrams of each part in Fig. 4, Fig. 6 is a flow chart of processing in the control circuit of the position detection circuit, and Fig. 7 (a) (b)
(c) is a timing diagram showing the basic position detection operation in the position detection circuit, FIG. 8 is a diagram showing the detection voltage obtained from each loop coil during the first position detection operation, and FIG. A timing diagram showing the second and subsequent position detection operations and phase detection operations, FIG. 10 is a diagram showing details of the data and processing device, and FIG. 11 shows a program that realizes the brush pen function and eraser function in the data processing device. FIG. 12 is a diagram showing a phase angle setting state corresponding to the program of FIG. 11, and FIG. 13 is a diagram showing an image when the input pen is moved while changing the writing pressure. DESCRIPTION OF SYMBOLS 10... Input pen, 11... Housing, ila... One end, 11, b... Other end, 12.13... Tuning circuit.

Claims (2)

[Claims] (1) A first tuning circuit that includes at least a coil and a capacitor and whose tuning frequency changes higher (or lower) than a predetermined frequency according to pen pressure; A position indicator characterized in that a second tuning circuit having a tuning frequency (or a high tuning frequency) is provided at both ends of a rod-shaped housing. (2) A first tuning circuit that includes at least a coil and a capacitor and whose tuning frequency changes higher (or lower) than a predetermined frequency according to the pen pressure; A position indicator characterized in that a second tuning circuit whose tuning frequency changes to lower (or higher) than a predetermined frequency is provided at both ends of a rod-shaped housing.