JPH07200136A - Coordinate detection device - Google Patents

Abstract

PURPOSE:To obtain a coordinate detection device which can detect not only the position of a pen, but also its thickness by calculating the distance between both coordinates from a signal indicating last detected coordinates and a signal indicating currently detected coordinates and judging the thickness of the pen from the calculated distance. CONSTITUTION:A resistance film input part 1 has an upper resistance film 3 and a lower resistance film 6 which are arranged opposite to each other at a certain interval and a transparent protection film which protects those, the upper resistance film 3 and lower resistance film 6 are formed out of transparent resistance films and arranged on the screen of a display device 5, and an input and a display part can be executed on the same coordinate surface. The pen 57 has, for example, four kinds of pen tip and the moment the pen 57 presses the resistance films 3 and 6, the coordinates of the tip of the pen 57 is detected (n) times, and, the distance between the last and current coordinates is found to specify the thickness of the pen tip, and then a process for drawing, etc., is performed on the basis of the detected size of the pen tip. Consequently, the trouble to set the thickness of the pen is eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate detecting device,
In particular, the present invention relates to a coordinate detection device that performs pen input with a tablet using a resistive film.

[0002]

2. Description of the Related Art In recent years, a pen input system has attracted attention as an input system for palmtop computers called Japanese word processors and personal digital assistants. Generally, a pen input system includes a tablet formed integrally with a display device, and moves a pen (stylus) on the tablet to input position information (coordinate information). Known methods for detecting the position of the pen on the tablet include a resistance film type, an electrostatic capacitance type, and a pressure sensitive type.

FIG. 7 shows the structure of a conventional resistance film type tablet. In FIG. 7, the resistance film input unit 1 has an upper resistance film 3 and a lower resistance film 6 which are opposed to each other with a constant interval. The upper resistance film 3 and the lower resistance film 6 are composed of transparent resistance films and are arranged on the screen of a display device (not shown) so that input can be performed on the display surface.

An electrode 5 is formed on the upper side of the upper resistance film 3 in the longitudinal direction. An electrode 5 is provided on the lower side of the upper resistance film 3.
An electrode 11 is formed in parallel with. An electrode 17 is formed on the right side portion of the lower resistance film 6 so as to be orthogonal to the electrodes 5 and 11 of the upper resistance film 3. Further, an electrode 23 is formed on the left side portion of the lower resistance film 6 in parallel with the electrode 17.

The a-side terminal of the switch 31 is connected to the electrode 5 of the upper resistance film 3 and applies a driving voltage Vdd to the electrode 5.
The b-side terminal of the switch 31 is connected to the electrode 17 of the lower resistance film 6 and applies the drive voltage Vdd. The a-side terminal of the switch 33 is connected to the electrode 23 of the lower resistance film 6, the electrode 23 is connected to the ground voltage, and the b-side terminal thereof is the electrode 11 of the upper resistance film 3.
To connect the electrode 11 to a ground voltage. The a-side terminal of the switch 35 is connected to the electrode 23 of the lower resistance film 6,
The voltage obtained through the electrode 23 is led to the noise elimination circuit 37, the b-side terminal is connected to the electrode 11 of the upper resistance film 3, and the voltage obtained through the electrode 11 is led to the noise elimination circuit 37.

The output of the noise elimination circuit 37 is connected to the input of an A / D (analog / digital) converter 39. A / D
The output of the converter 39 is connected to a coordinate detection system for performing coordinate detection.

In the conventional coordinate detecting device constructed as described above, when the switch 31 is set to the side a, the switch 33 is set to the side b, and the switch 35 is set to the side a, the electrode of the upper resistance film 3 is formed. A driving voltage Vdd is applied to the electrode 5, a ground voltage is applied to the electrode 11, and a current flows between the electrodes 5 and 11 of the upper resistance film 3. In this state, if it is assumed that the upper resistance film 3 and the lower resistance film 6 are brought into contact with each other at a position of coordinates (X, Y) by pressing with a pen (not shown),
The voltage V (X, Y) at the position of the coordinates (X, Y) is represented by the following equation when the total number of display dots between the electrodes 5 and 11 is represented by L1. V (X, Y) = Vdd · (L1−Y) / L1 This voltage V (X, Y) is applied to the lower resistance film 6 via the contact point.
Be transmitted to. Assuming that the input impedance of the noise elimination circuit 37 is sufficiently high, no voltage drop occurs in the lower resistance film 6, and this voltage V (X, Y) is applied to the electrode 23 and the switch 3.
It is supplied to the noise removal circuit 37 via 5.

The noise removal circuit 37 removes noise from the input signal and supplies it to the A / D conversion circuit 39. The A / D conversion circuit 39 converts the input analog voltage into a digital signal and outputs the digital signal to the coordinate detection system. The coordinate detection system detects the Y coordinate of the pressed position of the electronic pen from the supplied digital value.

After that, the switch 31, the switch 33, and the switch 35 are switched, the switch 31 is set to the side b, the switch 33 is set to the side a, and the switch 35 is set to the side b.
Set to the side. As a result, a current flows between the electrode 17 and the electrode 23 of the lower resistance film 6. In this state, the upper resistance film 3
If the lower resistance film 6 and the lower resistance film 6 are still in contact with each other at the coordinates (X, Y), the voltage V (X, Y) at the position of the coordinates (X, Y).
Is expressed by the following equation when the total number of dots between the electrodes 17 and 23 is represented by L2. V (X, Y) = Vdd · X / L2

This voltage V (X, Y) is transmitted to the upper resistance film 6 via the contact point. Assuming that the input impedance of the noise elimination circuit 37 is sufficiently high, no voltage drop occurs in the upper resistance film 3, and this voltage V (X, Y) is applied to the electrode 1
1, and is supplied to the noise elimination circuit 37 via the switch 35.

The noise removal circuit 37 removes noise from the input signal and supplies it to the A / D conversion circuit 39. The A / D conversion circuit 39 converts the input analog voltage into a digital signal and outputs it to the coordinate detection system. The coordinate detection system detects the X coordinate of the pressed position of the pen from the digital value.

After that, by switching the switches 31, 33 and 35 again, the Y coordinate of the new contact position can be obtained. In this way, the switches 31, 3
By continuously switching 3 and 35 in a short time, on the resistive film of the pen, that is, the contact surface of the tablet (= display surface)
The position above can be detected.

[0013]

As described above,
In the conventional resistance film type coordinate detection system, the position indicated by the pen or the like can be detected, but other information such as the thickness of the pen used cannot be detected. For this reason, when displaying input figures and characters on the display device,
It is necessary to display the selection screen in advance and set the line thickness and the like, and it is not easy to input characters and images according to the thickness of the pen used.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a coordinate detecting device capable of detecting not only the position of the pen but also the thickness of the pen.

[0015]

In order to achieve the above object, a coordinate detecting device according to a first aspect of the present invention comprises a first resistance film having electrodes substantially parallel to both ends thereof, and the first resistance film. A resistance film input section in which second resistance films having electrodes provided substantially parallel to both ends so as to be orthogonal to the electrodes of the first resistance film are arranged to face each other; between the electrodes of the first resistance film; and the second resistance film. Means for alternately supplying a current between the electrodes of the resistance film, a pen for pressing at least one of the first resistance film and the second resistance film to bring the resistance films into contact with each other, and the first for pressing the pen. A distance between the resistance film and the second resistance film is calculated from a detection unit that detects a signal indicating the coordinate of the contact position of the second resistance film, and a signal indicating the coordinate detected last time and a signal indicating the coordinate detected this time,
It is characterized by further comprising: a determination unit that determines the thickness of the pen based on the calculated distance.

The determination means, for example, executes the calculation of the distance a plurality of times, determines which of the predetermined ranges the calculated distance belongs to, and determines the thickness corresponding to the range to which the largest distance belongs. Is determined to be the thickness of the pen. For example, the determination means executes the distance calculation a predetermined number of times or a predetermined time immediately after pressing the first or second resistance film with the pen. Further, it may further include the coordinate detection device display means, and means for performing drawing according to the trajectory of the pen with the thickness of the pen determined by the determination means and causing the display means to display.

A handwriting input system according to a second aspect of the present invention includes a position pointing member and a contact surface of the position pointing member such as a tablet, and detects the position of the position pointing member on the contact surface. And a position detecting unit that detects a position indicated by the position indicating member a plurality of times, and a position variation detected by the detecting unit, and a degree of the determined variation. According to the above, a size detecting means for detecting the size of the contact portion at the position indicating portion is provided.

[0018]

In the pen input device and the like, the thicker the pen used (more accurately, the pen tip), the more the detected coordinates of the position of the pen tend to vary. Therefore, the thickness of the pen used can be determined by determining the degree of this variation.
Using this method, the coordinate detecting device according to the first aspect of the present invention calculates the distance between both coordinates from the signal indicating the previously detected coordinate and the signal indicating the currently detected coordinate, and based on the calculated distance. To determine the thickness of the pen.

As a specific method for determining the thickness of the pen, for example, the calculation of the distance is executed a plurality of times, and it is determined which of the predetermined ranges the calculated distance belongs to. A method of discriminating the thickness corresponding to the range to which the distance belongs from the thickness of the pen can be considered. The calculation of the distance may be performed a predetermined number of times or for a predetermined time immediately after the pen presses the first or second resistance film, and thereafter, drawing may be performed according to the trajectory of the pen with the detected thickness. Good.

According to the above arrangement, the thickness of the pen is automatically detected when a character or a figure is input, so it is not necessary to separately set the thickness of the pen. In other words, if the pen tip is selected according to the thickness of the line to be drawn, the line is automatically drawn with the thickness corresponding to the thickness of the pen tip, which simplifies the input.

Also in the handwriting input system according to the second aspect of the present invention, the variation in the position detected by the detecting means is discriminated, and the contact portion of the position pointing member is discriminated according to the degree of the discriminated variation. Detect size.

[0022]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a handwriting input system including the coordinate detection system of the present invention will be described below with reference to the drawings. FIG. 1 is a block diagram of a handwriting input system according to this embodiment. In FIG. 1, the same parts as those in FIG. 7 are designated by the same reference numerals.

As shown in FIG. 1, the resistance film input section 1 includes an upper resistance film 3 and a lower resistance film 6 which are arranged to face each other at a constant interval, and a transparent protective film (not shown) for protecting them. Have The upper resistance film 3 and the lower resistance film 6 are composed of transparent resistance films, and are arranged on the screen of the display device 53 described later.
Input and display can be executed on the same coordinate plane.

An electrode 5 is formed in the longitudinal direction on the upper side of the upper resistance film 3. An electrode 5 is provided on the lower side of the upper resistance film 3.
An electrode 11 is formed in parallel with. An electrode 17 is formed on the right side portion of the lower resistance film 6 so as to be orthogonal to the electrodes 5 and 11 of the upper resistance film 3. An electrode 23 is formed on the left side of the lower resistance film 6 in parallel with the electrode 17.

The a-side terminal of the switch 31 is connected to the electrode 5 of the upper resistance film 3 and applies the drive voltage Vdd to the electrode 5.
The b-side terminal of the switch 31 is connected to the electrode 17 of the lower resistance film 6 and applies the drive voltage Vdd. The a-side terminal of the switch 33 is connected to the electrode 23 of the lower resistance film 6, the electrode 23 is connected to the ground voltage, and the b-side terminal thereof is the electrode 11 of the upper resistance film 3.
To connect the electrode 11 to a ground voltage. The a-side terminal of the switch 35 is connected to the electrode 23 of the lower resistance film 6,
The voltage of the electrode 23 is led to the noise elimination circuit 37, the b-side terminal is connected to the electrode 11 of the upper resistance film 3, and the voltage of the electrode 11 is led to the noise elimination circuit 37.

The output of the noise removing circuit 37 is the A / D converter 3
9 and is converted into a digital signal. The output of the A / D converter 39 is supplied to the CPU 43 via the system bus 41.

The CPU 43 controls the entire coordinate detecting device, and is provided with four count registers CTR1 to CTR4 and a loop counter, which are arranged for each distance range, which will be described later. The RAM 45 is a readable / writable memory that stores various data of the CPU 43 and also has a CP.
Functions as a work area for U43. The ROM 47 is a read-only memory, which is a diagnostic program after the power is turned on.
A boot program for starting the coordinate detecting device, a program for detecting the thickness of the pen shown in FIG. 2 and the like are stored. A VRAM (video RAM) 49 is a bit map memory for storing drawing information. The display control device 51 controls transfer of display information from the VRAM 49 to the display device 53, transfer of display information from the CPU 43 to the VRAM 49, and the like.

The display device 53 is composed of, for example, a liquid crystal display device, and displays graphic and character information stored in the VRAM 49. The display device 53 is arranged below the upper resistance film 3 and the lower resistance film 6, and enables input and display on the same coordinate plane. The external interface 55 controls the exchange of data between this apparatus and an external apparatus as needed. The above components are connected by a system bus 41.
The pen (stylus) 57 is for pointing an arbitrary point on the display screen of the display device 53, and when the pen 57 is pressed, the upper resistance film 3 and the lower resistance film 6 come into contact with each other at the pressing point. A contact switch for detecting contact with the input surface is arranged at the tip of the pen 57. When the pen 57 touches the screen (transparent protective film), the contact switch is turned on, and this is done via the external interface 55. Is notified to the CPU 43.

A method of discriminating the thickness of the tip of the pen 57 by the coordinate detecting device having the above structure will be described. Generally, the detection coordinates at the moment when the pen presses the resistive film are not concentrated at one point as shown in FIG. 4, and the detection coordinates are scattered as the contact area increases. In other words, the thicker the pen tip, the greater the distance between the previously detected coordinate and the currently detected coordinate. Therefore, at the moment when the pen presses the resistive film,
The thickness of the pen tip can be specified by detecting the coordinates of the contact position a plurality of times and determining the distance between the detected coordinates.

Therefore, in the present embodiment, there are four types of pen tips of the pen 57, and at the moment when the pen 57 presses the resistance films 3 and 6, the coordinates of the tip of the pen 57 are n (n is an integer of 2 or more). 10 to 20 times is desirable), the thickness of the pen tip is specified by obtaining the distance between the coordinates of the previous time and this time, and thereafter, processing such as drawing is performed based on the detected size of the pen tip. To execute.

Next, the specific operation of the coordinate detection circuit shown in FIG. 1 will be described with reference to the flow charts of FIGS. 2 and 3, taking as an example the case of drawing on the display device 53 using the pen 57. The method of detecting the coordinates of the contact position of the pen 57 is the same as the conventional method. When the pen 57 comes into contact with the input surface integrated with the screen, the contact switch arranged at the tip of the pen 57 is turned on, and this ON signal is transmitted to the CPU 43 via the external interface 55. The CPU 43 executes the processing shown in FIGS. 2 and 3 in response to the ON signal.

The CPU 43 executes CP at step S1.
Count registers CTR1, CTR2, CT in U43
R3 and CTR4 are cleared to "0" and the loop count n is set in the loop counter (step S1).

The switches 31, 33 and 35 are the CPU 43.
The A / D converter 39 performs A / D conversion on the analog signal output from the noise removal circuit 37, and the A / D converter 39 sequentially transfers the analog signal to the CPU 43 directly or via a buffer or the like. Supply. The CPU 43 obtains the X and Y coordinates of the pressed point from the digital value output from the A / D converter 39 (step S3), and the obtained X and Y.
The coordinates are loaded into the X register and the Y register (step S5).

The CPU 43 reads the output of the A / D converter 39 and obtains the X and Y coordinates of the pressing point (step S7),
The distance is calculated according to the following equation from the difference between the previous X and Y coordinates Xreg and Yreg stored in the X register and the Y register and the X and Y coordinates X and Y obtained this time (step S
9). Z = {(Xreg-X) ² + (Yreg-Y) ² } ^1/2

The CPU 43 discriminates the magnitude of the distance Z in step S11 and executes the processing corresponding to the magnitude in steps S13 to S19. That is, when the distance Z is smaller than 3 (3 display dots), the CPU 43 causes the counter CT.
R1 is incremented by 1 (step S13). When the distance Z is 3 or more and less than 6, the CPU 43 causes the counter CTR.
2 is incremented by 1 (step S15). Distance Z
Is 6 or more and less than 9, the CPU 43 causes the counter CTR3
Is incremented by 1 (step S17). When the distance Z is 9 or more, the CPU 43 increments the counter CTR4 by 1 (step S19).

In this way, for each of the n distance measurements, the count value of the counter for the corresponding distance range is updated.

The CPU 43 subtracts 1 from the loop number n and judges whether or not n after the subtraction is "0" (step S2).
1). If it is not "0", the flow returns to step S5, and the processes of steps S5 to S21 are repeated. When it is determined in step S21 that the number of loops n-1 is "0", the values of the counters CTR1 to CTR4 are checked and the thickness corresponding to the counter having the largest value is determined by the pen 5
It is determined that the pen tip has a thickness of 7 (step S23).

That is, when the value of the counter CTR1 is the largest, it is determined that the thinnest pen is used, and when the value of the counter CTR2 is the largest, the second thinnest pen is used. When the value of the counter CTR3 is the largest, it is determined that the second thickest pen is used, and when the value of the counter CTR4 is the largest,
Determine that the thickest pen is used.

After that, the flow moves to the drawing process shown in FIG. First, the CPU 43 sets the previously read X and Y coordinates to X.
Store in register and Y register (step S25),
The output of the A / D converter 39 is read to obtain new X and Y coordinates (step S27). Next, the CPU 43 calculates the distance from the previous X and Y coordinates Xreg and Yreg stored in the X register and the Y register in step S9 and the X and Y coordinates X and Y obtained this time using the above-described formula (step S9). S29).

When the distance Z is 2 (display dots) or less, C
The PU 43 determines that the coordinates are correct coordinates, saves the coordinates as locus data in the RAM 45 as necessary based on the detected value, and corresponds to the detected thickness centered on the corresponding position of the VRAM 49. By writing the display data "1" in the range to be set, line drawing processing is performed (step S35).

For example, in step S23, the thin pen 57
When it is determined that the thick pen 57 is used, the display data “1” is written in a relatively narrow range around the detected coordinates of the VRAM 49 as shown in FIG. If it is determined that
As shown in (B), the display data "1" is written in a relatively wide range centered on the detected coordinates of the VRAM 49.

Thereafter, it is judged whether or not the drawing process is completed, for example, by judging whether or not the pen 57 is separated from the screen (step S35). If the drawing process is not completed, the flow is ended. Returns to step 25.

On the other hand, in step S31, the distance is 3
If it is determined that they are (3 display dots) or more apart, it is determined that the coordinates are incorrect dots (error), and the process jumps to step S35 without performing the line drawing process of step S33. If it is determined in step S35 that the drawing process has ended, the drawing process ends. After that, when the pen 57 comes into contact with the input surface, the processing from step S1 of FIG. 2 is started again.

For example, in the case where the upper "one" of the character "two" is written with a thick pen and the lower "one" is written with a thin pen, FIG.
As shown in (A), it is detected that the pen is thick at the tip of the "one" above, and then drawing is performed until the pen is separated by the detected pen thickness, and then FIG. As shown in, the pen is detected to be thin at the tip of the lower "one", and then drawing is performed until the pen is separated by the detected pen thickness.

In the above embodiment, the distance for specifying the thickness of the pen 57 is calculated n times, but the distance is calculated only for the time set by the software timer or the like. May be. The thickness of the pen is 4
The type is not limited. In this case, a number of counters CTR for each distance range are arranged according to the type of pen thickness. In the above embodiment, when the distance between the previous coordinate and the current coordinate is 2 (2 dots) or less at the time of drawing, the coordinate is set to be true,
When the coordinate is 3 or more, the coordinate is false, but the true / false reference may be another value.

As described above, in this embodiment, the thickness of the pen 57 used is determined by detecting the variation in the coordinates at the moment when the resistive films 3 and 6 are pressed by the pen 57, and thereafter, the thickness is continuously determined. The input coordinates are determined to have been input with a pen of the same thickness (until the pen is released), and figures and characters are drawn. Therefore, it is possible to draw a line having a thickness corresponding to the thickness of the pen without setting the thickness of the line. In addition, when drawing, the distance between the previous detected position and this detected position is calculated, and only when this distance is less than a certain value, the coordinates are judged to be correct (true) and used for drawing. It is possible to draw various images.

The present invention is not limited to the above embodiment. For example, in the above embodiment, the contact switch is arranged at the tip of the pen 57 to determine whether or not the pen 57 has come into contact with the screen (input surface). However, for example, the A / D converter 3
It may be determined that the pen 57 has touched the screen when the value output from 9 changes to a value other than “0”.

Further, in the above embodiment, the case where the drawing is performed with the detected pen thickness is described, but the process after detecting the pen thickness is arbitrary. For example, FIG. 5 (A), (B)
In the above, if "0" is written instead of the display data "1", the display on the locus of the pen is erased with a width corresponding to the thickness of the pen, and a so-called eraser function can be realized.

In the above embodiment, the distance between the detected position at the previous time and the detected position at this time is obtained in order to obtain the degree of dispersion (dispersion) of the coordinates, but other methods may be used. For example, the coordinates may be detected n times, the standard deviation σ thereof may be obtained, and the thickness of the pen tip may be detected from this value.

Although the resistive film type coordinate detecting circuit has been described in the above embodiments, the present invention is not limited to this, and can be applied to various types of coordinate detecting circuits. For example, even in an electrostatic coupling type coordinate detection circuit or the like, the variation in the detected coordinates tends to increase as the tip of the pen becomes thicker, and the present invention can be applied. The configuration for designating the position does not have to be a pen (stylus) type, and its shape is arbitrary as long as the position on the tablet can be designated.

[0051]

As described above, according to the present invention, the thickness of the pen is determined from the variation in the distance between the positions of the pens, and thereafter, drawing is performed with the thickness until the pen is separated from the resistive film. Therefore, it suffices to select the pen according to the thickness of the character in the figure, and the trouble of setting the thickness of the pen is eliminated. In addition, the thickness of the pen can be detected without changing the hardware configuration of a normal pen input system.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a coordinate detecting device of the present invention.

FIG. 2 is a flowchart for explaining a process of detecting the thickness of a pen.

FIG. 3 is a flowchart for explaining drawing processing.

FIG. 4 is a diagram showing a relationship between a pen tip thickness and a detection position.

FIG. 5 is a diagram illustrating a line drawing process.

FIG. 6 is a diagram illustrating a process when drawing “two”.

FIG. 7 is a block diagram showing a configuration example of a conventional coordinate detection device.

[Explanation of sign]

1 ... Resistive film input section, 3 ... Upper resistive film, 5, 11,
17, 23 ... Electrodes, 6 ... Lower resistance film, 31, 33,
35 ... Switch, 37 ... Noise elimination circuit, 39 ...
A / D converter, 41 ... System bus, 43 ... CP
U, 45 ... RAM, 47 ... ROM, 51 ... V
RAM, 51 ... Display control device, 53 ... Display device, 5
5 ... External interface, 57 ... Pen

Claims (5)

[Claims] 1. A first resistance film having electrodes substantially parallel to both ends, and a second resistance film having electrodes substantially parallel to both ends so as to be orthogonal to the electrodes of the first resistance film. A resistance film input section in which films are arranged to face each other; a means for alternately supplying a current between electrodes of the first resistance film and between electrodes of the second resistance film; and the first resistance film and the second resistance. A pen that presses at least one of the films to bring the two resistive films into contact with each other; a detection unit that detects a signal indicating the coordinates of the contact position of the first resistive film and the second resistive film by the pressing of the pen; A coordinate detecting apparatus comprising: a determination unit that calculates a distance between both coordinates from a signal indicating the coordinates and a signal indicating the coordinates detected this time, and determines the thickness of the pen based on the calculated distance. 2. The determination means executes the calculation of the distance a plurality of times, determines which of the predetermined ranges the calculated distance belongs to, and determines the thickness corresponding to the range to which the largest distance belongs. The coordinate detection device according to claim 1, wherein the thickness of the pen is determined. 3. The determination means executes the distance calculation a predetermined number of times or a predetermined time immediately after pressing the first or second resistance film with the pen. Coordinate detection device. 4. The coordinate detection device according to claim 1, further comprising display means for performing drawing according to a trajectory of the pen with the thickness of the pen determined by the determination means and displaying the drawn image. 5. An input system, comprising: a position indicating member; and a position detecting unit for detecting a position of the position indicating member on the contact face, wherein the position detecting unit comprises: A position detecting unit that detects the position indicated by the position indicating member a plurality of times, and a position variation detected by the position detecting unit is determined, and the size of the contact portion of the position indicating member is determined according to the degree of the determined variation. A handwriting input system comprising size detecting means for detecting.