JP2837858B2 - Coordinate input device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a coordinate input device capable of inputting characters and figures drawn with a brush.

(Prior Art) As a conventional coordinate input device of this type, a pressure-sensitive sensor using a pressurized conductive rubber or the like is provided in an input indicator, and a position is indicated on the tablet by the input indicator. In some cases, the writing pressure is detected during the writing and the thickness of the line is changed in accordance with the writing pressure so that characters and figures as if drawn with a writing brush can be input.

(Problems to be Solved by the Invention) However, in the above-mentioned device, in order to accurately transmit the pen pressure applied to the input indicator to the pressure-sensitive sensor, a highly rigid core body is provided at the tip of the input indicator only in one direction. Since it must be movably provided, it cannot be used with its tip bent like a brush, and a large displacement cannot be obtained with a pressure-sensitive sensor using conductive rubber or the like. The amount of displacement (stroke) at the tip of the indicator cannot be increased, and therefore, there is a problem that the same operational feeling as a real brush cannot be obtained.

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems and to provide a coordinate input device capable of changing the thickness of a character or graphic line with the same feeling as a real brush.

(Means for Solving the Problems) In the present invention, in order to achieve the above object, in a coordinate input device that transmits and receives signals between an input indicator and a tablet and detects a position indicated by the input indicator, A writing tip made of a hairy or similar material is provided at the tip of the input indicator, and a height at which the height of the input indicator is detected from the level of a signal transmitted and received between the tablet and the input indicator. A coordinate input device that is provided with a detecting unit and changes a parameter of a portion corresponding to the indicated position according to the detected height of the input indicator; and a coil or a coil input device in the coordinate input device. A tuning circuit consisting only of a passive element such as a capacitor and tuned to a predetermined frequency is provided, a radio wave generating means for generating a radio wave of the predetermined frequency in the tablet, and a radio wave detecting means for detecting the radio wave of the predetermined frequency. Proposes a coordinate input device provided with a position detecting means for detecting a position indicated by said input indicator based on the electric wave detected by the electric wave detection means and the electric wave detection means.

(Operation) According to the coordinate input device of the present invention, when the tip of the input indicator is used in contact with the tablet, the writing tip made of a hairy or similar material is deformed according to the writing pressure,
The height of the input indicator on the tablet changes.
When the height, that is, the distance between the input indicator and the tablet changes, the level of the signal transmitted and received during the change changes, and the height of the input indicator is changed by the height detecting means from the level of this signal. The detected parameter is changed, and accordingly, the parameter of the part corresponding to the designated position, for example, the spread of the figure is changed.

According to the coordinate input device of the present invention, when a radio wave of a predetermined frequency is generated by the radio wave generation means of the tablet,
The radio waves are tuned, that is, received by the tuning circuit of the input indicator used on the tablet, but the tuning circuit that has received the radio waves transmits or reflects similar radio waves. The reflected radio wave is detected by the radio wave detecting means of the tablet, and the detected radio wave is further transmitted to the coordinate detecting means of the tablet, and the position indicated by the input indicator is detected. At this time, the radio wave detected by the radio wave detection means of the tablet is sent to the height detection means, and the height of the input indicator is detected from the level as in the above-described manner. The parameters of the part to be changed are changed.

(Embodiment) FIG. 1 shows an outline of an embodiment of a coordinate input device according to the present invention, in which 1 is a tablet, 2 is an input indicator,
For example, a pen 3 is a host computer, and 4 is a display device.

FIG. 2 shows details of the tablet 1 together with a tuning circuit of the brush pen 2 described later. In the figure, 5 is a position detecting unit, 6 is a control circuit, 7 is a signal generating circuit, 8 and 9
Is a selection circuit for the X and Y directions, 10 and 11 are transmission / reception switching circuits, 12 is an XY switching circuit, 13 is a reception timing switching circuit, 14
Is a band-pass filter (BPE), 15 is a detector, 16 is a low-pass filter (LPF), 17 and 18 are drive circuits, and 19 and 20 are amplifiers.
These are all accommodated in a case made of a nonmetallic material.

FIG. 3 shows details of the loop coil group 5x in the X direction and the loop coil group 5y in the Y direction, which constitute the position detecting section 5. A large number, for example, 48 loop coils 5x-1, 5x-2,..., 5x arranged in parallel with each other at predetermined intervals in the X direction so as to overlap with each other in the X direction.
−48, and a number of loop coils 5y in the Y direction are arranged in parallel at a predetermined interval from each other in the Y direction and are arranged so as to overlap with each other.
5y-2, ... 5y-48, loop coil group in X direction
The 5x and the Y-direction loop coil groups 5y are closely overlapped with each other (however, they are drawn apart in the drawings for easy understanding). Here, each loop coil is constituted by one turn, but may be constituted by a plurality of turns as necessary.

FIG. 4 shows a specific structure of the brush pen 2, in which a pen shaft 21 made of a non-metallic material such as a synthetic resin and a brush-like member attached to one end of the pen shaft 21 such as a brush 22 are shown. A coil 23 containing a core housed inside the pen shaft 21 and a capacitor 24. In addition, specifically, the coil
For 23, a rod-shaped ferrite core with a diameter of 6 mm and a length of 30 mm and a litz wire of 0.2 mm in diameter (specifically, five wires of 0.02 mm in diameter) wound around 100 turns is used. As the capacitor 24, a multilayer ceramic chip capacitor is used. Further, instead of the brush 22, a brush tip having a structure made of rubber or the like may be used.

As shown in FIG. 2, the coil 23 and the capacitor 24 are connected in series with each other to form a well-known tuning circuit 25. The inductance of the coil 23 and the capacitance value of the capacitor 24 are adjusted by the tuning ( (Resonance) frequency is set to a value that is substantially equal to a predetermined frequency f0.

The host computer 3 receives the coordinate value and the height information of the designated position transmitted from the tablet 1, performs predetermined data, and transmits the obtained information to the display device 4 for display.

Next, the operation of the apparatus will be described together with its configuration. First, how radio waves are transmitted and received between the tablet 1 and the pen 2 and the signals obtained at this time will be described with reference to FIG.

The control circuit 6 comprises a well-known microprocessor or the like, controls the signal generation circuit 7, and controls switching of each loop coil of the position detection unit 5 via the selection circuits 8 and 9 according to the flowchart shown in FIG. And also
The XY switching circuit 12 and the reception timing switching circuit 13 control the switching of the coordinate detection direction, and furthermore, a reduction filter.
The output value from the pen 16 is converted from analog to digital (A / D), and the arithmetic processing described later is executed to obtain the coordinate value of the position pointed by the pen 2. And sends them to the host computer 3.

The selection circuit 8 is for sequentially selecting one loop coil from the X-direction loop coil group 5x, and the selection circuit 9 is for sequentially selecting one loop coil from the Y-direction loop coil group 5y. And operates according to the information from the control circuit 6.

The transmission / reception switching circuit 10 alternately connects the selected one loop coil in the X direction to the driving circuit 17 and the amplifier 19, and the transmission / reception switching circuit 11 includes the one loop coil in the selected Y direction. Are alternately connected to the drive circuit 18 and the amplifier 20, which operate according to a transmission / reception switching signal described later.

The signal generation circuit 7 generates a rectangular wave signal A having a predetermined frequency f0, for example, 500 kHz, a transmission / reception switching signal B and a reception timing signal C having a predetermined frequency fk, for example, 15.625 kHz. The rectangular wave signal A is converted into a sine wave signal D by a reduction filter (not shown),
Sent to either one of 17 or 18, and the transmission / reception switching signal B is transmitted to the transmission / reception switching circuits 10 and 11, and
The reception timing signal C is sent to the reception timing switching circuit 13.

Assuming now that information for selecting the X direction from the control circuit 6 has been input to the XY switching circuit 12 and the reception timing switching circuit 13, the sine wave signal D is sent to the driving circuit 17 and converted into a balanced signal. The signal is sent to the transmission / reception switching circuit 10. The transmission / reception switching circuit 10 outputs the signal to the selection circuit 8 from the transmission / reception switching circuit 10 in order to switch and connect one of the driving circuit 17 and the amplifier 19 based on the transmission / reception switching signal B. The signal is a signal E for outputting or not outputting a signal of 500 kHz every time T (= 1 / 2fk), here, every 32 μsec.

The signal E is sent to one loop coil 5x-i (i = 1, 2,..., 48) in the X direction of the position detection unit 5 via the selection circuit 8, and the loop coil 5x-i is A radio wave based on the signal E is generated.

At this time, the brush pen 2 is substantially upright on the tablet 1,
That is, when held in use, the radio wave excites the coil 23 of the brush pen 2 and causes the tuning circuit 25 to generate an induced voltage F synchronized with the signal E.

Thereafter, when the signal E enters a period in which there is no signal, that is, the reception period, and the loop coil 5x-i is switched to the amplifier 19 side, the radio wave from the loop coil 5x-i immediately disappears, but the induced voltage F It gradually attenuates according to the loss in the tuning circuit 25.

On the other hand, the current flowing through the tuning circuit 25 based on the induction voltage F causes the coil 23 to receive radio waves. The radio wave is an amplifier
In order to excite the loop coil 5x-i connected to 19 in reverse, an induced voltage by radio waves from the coil 23 is generated in the loop coil 5x-i. The induced voltage is sent from the transmission / reception switching circuit 10 to the amplifier 19 only during the reception period, amplified and becomes a reception signal G, and further transmitted to the reception timing switching circuit 13.

In the reception timing switching circuit 13, either one of the selection information in the X direction or the Y direction, here, the selection information in the X direction,
A reception timing signal C, which is substantially an inverted signal of the transmission / reception switching signal B, is input. The reception signal G is output while the signal C is at the high (H) level, and the reception signal G is output during the low (L) level. Since nothing is output, a signal H (substantially the same as the reception signal G) is obtained at the output.

The signal H is sent to the bandpass filter 14. The bandpass filter 14 is a ceramic filter having a frequency f0 as a unique frequency, and the signal H having an amplitude corresponding to the energy of the frequency f0 component in the signal H. (Strictly, in the state where several signals H are input to the bandpass filter 14 and converge), are transmitted to the detector 15.

The signal I input to the detector 15 is detected and rectified,
After the signal J, a filter with sufficiently low cutoff frequency
At 16, a voltage value corresponding to almost half of the amplitude, for example, Vx
And transmitted to the control circuit 6.

The voltage value Vx of the signal K is expressed by the brush pen 2 and the loop coil 5x−
a value dependent on the distance to the variable i, here a value substantially inversely proportional to the fourth power of the distance, and changes when the loop coil 5x-i is switched, so that the voltage obtained for each loop coil in the control circuit 6 By converting the value Vx into a digital value and performing an arithmetic process described later on the digital value,
Thus, the coordinate value of the designated position in the X direction is obtained. In addition,
The coordinate value in the Y direction of the position pointed by the pen 2 is obtained in the same manner.

On the other hand, the distance between the brush pen 2 and the loop coil 5x-i in the X direction (or the loop coil 5y-i in the Y direction) is
Varies with the height with respect to the position detection unit 5, that is, the height h with respect to the tablet 1. Therefore, the voltage value Vx of the signal K is a value that also depends on the height h of the brush pen 2 with respect to the tablet 1, and here is a value substantially inversely proportional to the square of the height h.

As described above, the X direction (or Y direction) of the position detection unit 5
The induced voltage generated in each of the loop coils differs according to the position of the brush pen 2 in the X direction (or Y direction). Therefore, in order to determine the height, the unique voltage in the X direction (or Y direction) of the brush pen 2 is determined. It is necessary to find a voltage value corresponding to a position, for example, directly below the brush pen 2 at which the maximum value of the induced voltage is obtained, or a value corresponding thereto.

By the way, since the respective loop coils in the X direction (or the Y direction) of the position detecting unit 5 are arranged at a predetermined interval from each other as described above, the voltage obtained from each loop coil in the X direction (or the Y direction) is obtained. The value is essentially a discrete value in the induced voltage that shows a continuous change. For this reason, the voltage value obtained from the loop coil closest to the brush pen 2 in the X direction (or the Y direction) is not always the maximum value of the above-described induced voltage.

Therefore, in practice, a predetermined calculation process is performed on a voltage value obtained from each loop coil in the X direction (or the Y direction) to obtain a maximum value of the induced voltage, and a table prepared in advance is used.
That is, a plurality of (for example, 60 steps) heights h of the brush pen 2 with respect to the tablet 1 are compared with a table corresponding to a plurality of maximum values of the induced voltage to determine the height h, or the position indicated by the brush pen 2 That is, the difference between the coordinate value in the X direction (or Y direction) of the position where the induced voltage shows the maximum value and the position of the loop coil in the X direction (or Y direction) where the maximum voltage value is obtained (hereinafter, this is referred to as Is referred to as a deviation σ), and the deviation σ and the maximum voltage value are converted into a table prepared in advance, that is, a plurality of heights h of the pen 2 with respect to the tablet 1 are converted into a plurality of deviations σ and the maximum voltage value, respectively. The height h is obtained by comparing with the corresponding table.

Here, the loop coil 5x- in the X direction (or Y direction)
The deviation σ obtained at the time of calculating the X-direction (or Y-direction) coordinate value of the designated position of the brush pen 2 from the value obtained by A / D conversion of the voltage value for each i (or 5y-i) and the deviation σ And the maximum voltage value of the brush pen 2 according to the latter method described above.
Of the tablet 1 with respect to the tablet 1 is determined.

The calculated height h is transferred to the host computer 3 together with the coordinate values of the designated position in the X and Y directions.

Next, referring to FIGS. 5 to 10, a description will be given in detail of the coordinate detection operation and the height detection operation, as well as the creation of the image data based on the coordinate value and the height information of the designated position.

First, when the power of the entire apparatus is turned on and the measurement is started, the control circuit 6 transmits information for selecting the X direction to the XY switching circuit.
12 and to the reception timing switching circuit 13,
The information for selecting the first loop coil 5x-1 among the loop coils 5x-1 to 5x-48 in the X direction of the position detection unit 5 is sent to the selection circuit 8, and the loop coil 5x-1 is transmitted to the transmission / reception switching circuit 10.
Connect to

The transmission / reception switching circuit 10 alternately connects the loop coil 5x-1 to the driving circuit 17 and the amplifier 19 based on the transmission / reception switching signal B described above. At this time, the driving circuit 17 operates during the transmission period of 32 μsec in FIG. 500kHz 16 as shown in (a)
Sine wave signals are sent to the loop coil 5x-1 (note that
FIG. 5 shows only five of them for the sake of illustration. ).

The switching between the transmission and the reception is repeated seven times for one loop coil, here 5x-1, as shown in FIG. 7 (b). The seven transmission and reception repetition periods correspond to one loop coil selection period (488 μsec).

At this time, an induced voltage is obtained from the output of the amplifier 19 every seven reception periods for one loop coil, and this induced voltage is transmitted to the bandpass filter 14 via the reception timing switching circuit 13 as described above. The signal is transmitted, averaged, and transmitted to the control circuit 6 via the detector 15 and the low-pass filter 16.

The control circuit 6 performs A / D conversion of the output value of the low-pass filter 16 and inputs it, and temporarily stores it as a detection voltage depending on the distance between the brush pen 2 and the loop coil 5x-1, for example, Vx1.

Next, the control circuit 6 sends information for selecting the loop coil 5x-2 to the selection circuit 8, connects the loop coil 5x-2 to the transmission / reception switching circuit 10, and sets the distance between the brush pen 2 and the loop coil 5x-2. The detection voltage Vx2 depending on the time is obtained and stored, and thereafter the loop coils 5x-3 to 5x-48 are sequentially connected to the transmission / reception switching circuit 10 in the same manner, and each loop coil as shown in FIG. Detection voltage Vx depending on the distance in the X direction from the pen 2
1 to Vx48 (however, only a part thereof is shown in an analog representation in FIG. 7C).

As shown in FIG. 8, the actual detection voltage is obtained only in a few loop coils before and after the position (xp) where the brush pen 2 is placed as a center.

The control circuit 6 checks whether or not the voltage value of the stored detection voltage is equal to or higher than a certain detection level. If the voltage value is equal to or lower than the certain detection level, the control circuit 6 again selects each loop coil in the X direction and detects the voltage. Repeat, if it is above a certain detection level, proceed to the next process.

Next, the control circuit 6 sends the selection information in the Y direction to the XY switching circuit 12 and the reception timing switching circuit 13, switches the selection circuit 9 and the transmission / reception switching circuit 11 in the same manner as described above, and controls the low band when transmitting and receiving radio waves. The brush pen 2 obtained by A / D converting the output value of the filter 16 and each of the Y-direction loop coils 5y-1 to 5y-48
Is temporarily stored. After this,
A level check is performed in the same manner as described above, and if it is below a certain detection level, the process returns to the selection of each loop coil in the X direction and voltage detection again. As will be described later, the coordinates of the position pointed by the pen 2 in the X and Y directions are calculated, the height h of the pen 2 is calculated, and these are transferred to the host computer 3.

When the first coordinate detecting operation and the height detecting operation are completed in this manner, the control circuit 6 performs the X-direction loop coil 5x-1 as the second and subsequent coordinate detecting operations as shown in FIG. 5x-48, a selection circuit 8 is used to select information for selecting only a certain constant before and after the loop coil at which the maximum detection voltage is obtained, for example, only 10 loop coils.
And the Y-direction loop coils 5y-1 to 5y-48
Out of the loop coil from which the maximum detected voltage is obtained, a constant number of the loop coil and the information for selecting only the ten loop coils are sent to the selection circuit 9, and the output value is obtained in the same manner as described above. A coordinate detection operation and a height detection operation in the X direction and the Y direction with respect to the brush pen 2 are performed, and the obtained coordinate value and height information of the designated position are transferred to the host computer 3, and thereafter, these operations are repeated.

In addition, if the level check described above is explained in detail,
Check whether the maximum value of the detection voltage has reached the detection level and which loop coil has the maximum value of the detection voltage, and if the detection level has not been reached, stop the subsequent coordinate calculation and the like. This is a process of setting the center of the loop coil to be selected in the next coordinate detection operation and phase detection operation.

X-direction or Y-direction coordinate values, for example, as one method of calculating the coordinate value xp, approximate the waveform near the maximum value of the detection voltage Vx1 ~ Vx48 with a suitable function, the coordinates of the maximum value of the function There is a way to ask.

For example, in FIG. 7 (c), the maximum detection voltage Vx3
, And the detection voltages Vx2 and Vx4 on both sides thereof can be calculated as follows by approximation by a quadratic function (however, the coordinate values of the center position of each loop coil 5x-1 to 5x-48 are x1 to
x48, and the interval is Δx. ). First, from each voltage and coordinate value, Vx2 = a (x2-xp) ² + b (1) Vx3 = a (x3-xp) ² + b (2) Vx4 = a (x4-xp) ² + b ... ... (3) Here, a and b are constants (a <0). X3−x2 = Δx (4) x4−x2 = 2Δx (5) Substituting the expressions (4) and (5) into the expressions (2) and (3) and rearranging them, xp = x2 + Δx / 2 ｛(3Vx2-4Vx3 + Vx4) / (Vx2-2Vx3 + Vx4)｝ (6) .

Therefore, the maximum value of the detection voltage obtained in the level check and the detection voltages before and after the maximum value are extracted from each of the detection voltages Vx1 to Vx48. The coordinate value xp of the brush pen 2 can be calculated by performing an operation corresponding to the above equation (6) from the coordinate value (known) of the previous loop coil.

The height h of the brush pen 2 at this time is the latter half of the equation (6), that is, the deviation σ σ = Δx / 2 ｛(3Vx2-4Vx3 + Vx4) / (Vx2-2Vx3 + Vx4)｝ ... (7) and the maximum Can be calculated by comparing the voltage value Vx3 with a table prepared in advance.

On the other hand, the host computer 3 stores the data transferred from the control circuit 6 in accordance with the flowchart shown in FIG. 10, and stores the height information therein as a parameter of a portion corresponding to the designated position (coordinate point), such as a diameter of a circle. Converted to spread information of a simple figure (for example, converted to a value proportional to the height h)
Then, a figure of a circle having the diameter is drawn at a coordinate position based on the coordinate values in the X direction and the Y direction in an image memory (not shown), sent to the display device 4, and displayed on the screen.

Since the above process is repeated while data is transferred from the control circuit 6, when a half-paper is laid on the tablet 1 and characters are written in the brush 22 of the brush pen 2 with black ink, a normal text is written on the half-paper. As the brush character is drawn, circles 27 of different diameters are continuously arranged along the locus 26 of the designated position as shown in FIG. 11, and the thickness of any line similar to the brush character on the half paper is changed. The resulting image is obtained.

FIGS. 12 (a) and 12 (b) show another example of a display image by the present apparatus, and FIG. 12 (a) shows an image when a kanji character "creativity" is input. (B) "Effort"
This shows an image obtained when the user inputs a kanji character and performs a process of painting the inside of the circle.

The obtained image can be converted into a hard copy by a printer (not shown) or the like, if necessary, or transmitted to another device via a telephone line or the like.

In the above embodiment, the height information is converted into the diameter of the circle indicating the designated position. However, by changing the program of the host computer 3, the spread information of an arbitrary figure, for example, "the major axis of the ellipse", "the length of the rectangle" And so on.

Further, as shown in FIG. 13, in a rectangular graphic 28 whose length changes according to the height information, when a `` rectangular rectangle 28 'with a part cut off''is inserted in correspondence with the height information in a predetermined range. , An image 29 expressing “blurring” can be obtained.

Note that the number of loop coils and the arrangement thereof in the embodiment are merely examples, and it is needless to say that the present invention is not limited to this.

In the above embodiment, the loop coil for transmitting the radio wave and the loop coil for receiving the radio wave are switched and used as one loop coil, but they may be provided separately.

Further, in the above-described embodiment, the coordinate input device that transmits a radio wave from the tablet side to the input indicator and receives the reflected radio wave to perform position detection and the like is used, but the radio wave transmitted from the tablet side is used as the input indicator. It is also possible to use a well-known electromagnetic induction type coordinate input device or the like that receives on the tablet side or receives on the tablet the radio wave transmitted from the input indicator.

(Effect of the Invention) As described above, according to the coordinate input device of the present invention,
The writing indicator made of a hairy or similar material is provided at the tip of the input indicator, so that the tip can be bent and used with the same feeling as a normal writing brush, and the displacement can be increased. The tablet further comprises height detecting means for detecting the height of the input indicator from the level of a signal transmitted and received between the tablet and the input indicator, according to the detected height of the input indicator. To change the parameters of the part corresponding to the indicated position, the information on the height of the input indicator can be obtained only by using the input indicator on the tablet. The parameters of the part, for example, the extent of the figure are changed,
You can change the line thickness of characters and figures.

According to the coordinate input device of the present invention, the input indicator includes only a passive element such as a coil or a capacitor and is provided with a tuning circuit for tuning to a predetermined frequency, and the tablet generates the radio wave of the predetermined frequency. Radio wave generating means, a radio wave detecting means for detecting the radio wave of the predetermined frequency, and a position detecting means for detecting a position indicated by the input indicator based on the radio wave detected by the radio wave detecting means. Cables and the like between the indicator and the tablet are no longer required, and heavy parts such as batteries and magnets are not required on the input indicator side. Operability at the time is improved.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing an outline of an embodiment of a coordinate input device according to the present invention, FIG. 2 is a block diagram showing details of a tablet together with a tuning circuit of a brush pen, and FIG. FIG. 4 is a detailed configuration diagram of a loop coil group in the X direction and the Y direction of the position detection unit, FIG. 4 is a cross-sectional view of a brush pen, FIG. 5 is a signal waveform diagram of each unit in FIG.
The figure is a flowchart of the processing in the control circuit, FIG. 7 (a)
(B) and (c) are timing diagrams showing a basic coordinate detecting operation in the control circuit, FIG. 8 is a diagram showing a detected voltage obtained from each loop coil at the time of the first coordinate detecting operation,
FIG. 9 is a timing chart showing the coordinate detection operation and the height detection operation from the second time onward, FIG. 10 is a flowchart of processing in the host computer, and FIG. 11 is a display when the brush pen is moved while changing the height. Figures showing images, FIGS. 12 (a) and (b)
FIG. 13 is a diagram showing another example of a display image, and FIG. 13 is an explanatory diagram showing another example of a figure showing a designated position that changes in accordance with height information and an example of a display image drawn by this figure. 1 tablet, 2 brush pen, 3 host computer, 4 display device, 5 position detector, 5x X
Direction loop coil group, 5y loop coil group in Y direction, 6 control circuit, 7 signal generation circuit, 8 selection circuit in X direction, 9 selection circuit in Y direction, 10, 11 ... Transmission / reception switching circuit, 12 ... XY switching circuit, 13 ... Reception timing switching circuit, 14 ... Band filter, 15 ... Detector, 16 ...
Low-pass filter, 22… brush, 23… coil, 24… capacitor, 25… tuning circuit.

────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Takahiko Funabashi 5-23-4 Sakurada, Washinomiya-cho, Kita-Katsushika-gun, Saitama Prefecture Inside Wacom Co., Ltd. (56) References JP-A-61-59523 (JP, A) JP-A Sho 63-307522 (JP, A) (58) Fields investigated (Int. Cl. ⁶ , DB name) G06F 3/03

Claims (2)

(57) [Claims] 1. A coordinate input device for transmitting and receiving signals between an input indicator and a tablet and detecting a position indicated by the input indicator, wherein a tip of the input indicator is made of a hairy or similar material. A writing tip, and height detecting means for detecting the height of the input indicator from the level of a signal transmitted and received between the tablet and the input indicator, the height of the detected input indicator being provided. A coordinate input device characterized by changing a parameter of a part corresponding to a designated position according to the position. 2. An input indicator is provided with a tuning circuit consisting of only passive elements such as coils and capacitors and tuned to a predetermined frequency, and a radio wave generating means for generating a radio wave of the predetermined frequency on a tablet; And a radio wave detecting means for detecting a radio wave having a frequency of the predetermined frequency and a position detecting means for detecting a position indicated by the input indicator based on the radio wave detected by the radio wave detecting means. Coordinate input device as described.