JP2002023939A - Input device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an input device capable of accurately calculating written information. SOLUTION: The input device is provided with a writing material 2 and a processing part 21 for calculating writing information. The writing material 2 is provided with an acceleration sensor 11 capable of detecting respective acceleration respectively corresponding to two acceleration detecting axes orthogonally crossing with each other on intersecting planes intersecting with each other in the longitudinal direction of the writing material 2 and an angular velocity sensor 12 capable of detecting two rotational angular velocity of the writing material 2 which respectively correspond to two rotational angular velocity detecting axes orthogonally crossing with each other on the intersecting planes. The processing part 21 calculates writing information by finding out the respective rotational angles of the two acceleration detecting axes which are detected before and after a slight time in writing operation on the basis of the respective detected rotational angular velocity and converting respective acceleration corresponding to the two acceleration detecting axes detected after the slight time into respective acceleration values corresponding to the two acceleration detecting axes before the slight time.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an input device for calculating writing information based on a sensor signal of an acceleration sensor which is used in an information processing device such as a computer, a word processor and an electronic organizer and which is provided in a pen-type writing instrument. It is about.

[0002]

2. Description of the Related Art In recent years, various input devices have been proposed which calculate writing information such as the acceleration and movement amount of a tip writing portion of a writing implement based on an acceleration detection signal detected by an acceleration sensor built in the writing implement. As an input device of this type, the inventor has already proposed a handwriting input device provided with a writing instrument 51 shown in FIG.
issue). In this handwriting input device, when writing is performed using the writing instrument 51, the acceleration sensor 52 for the X direction and the acceleration sensor for the Y direction (not shown) built in the writing instrument 51 generate an acceleration detection signal in the X direction and a Y direction. Are respectively detected. Next, the handwriting input device main body integrates the acceleration detection signal in the X direction and the acceleration detection signal in the Y direction twice, respectively, to generate a displacement signal in the X direction and a displacement signal in the Y direction. Based on this, the handwriting written by the writing implement 51 is reproduced.

[0003]

However, the handwriting input device proposed by the inventor has the following points to be improved. In addition, in order to facilitate understanding, the writing instrument 51 is moved along the X direction on the writing plane below.
A case in which a written character is reproduced based only on the acceleration detection signal output from the acceleration sensor 52 will be described as an example. It is assumed that the gravitational acceleration is ignored and the writing implement 51 is moved at the acceleration a (t). Normally, in the writing operation using the writing implement 51, the inclination of the writing implement 51 with respect to the vertical direction during the writing operation is generally different from the inclination of the writing implement 51 with respect to the vertical direction at the start of the writing operation. In this case, for example, as shown in FIG.
The inclination of the writing instrument 51 with respect to the vertical direction at the start of the writing operation is defined as an angle θ (t1), and as shown in FIG.
In the case of 2), the acceleration as on the detection plane at the start of the writing operation detected by the acceleration sensor 52
(T1) is represented by a (t) · COS θ (t1), and the acceleration as (t2) on the detection plane during the writing operation is
a (t) · COS θ (t2). Therefore, although the writing implement 51 is moved along the X direction at the acceleration a (t), the detected acceleration includes a (t) ·
An error of (COS θ (t1) −COS θ (t2)) occurs. Therefore, an error occurs in the handwritten information. Therefore, it is desired that the handwritten input device has improved accuracy of the handwritten information.

In the handwriting input device proposed by the inventor, the written characters written by the writing implement 51 are reproduced based on the accelerations in the X and Y directions detected by the acceleration sensor 52. . Therefore,
If the writing instrument 51 is moved in the axial direction during the writing operation, the movement cannot be detected, and it may be difficult to accurately reproduce the written characters. It is preferable to improve this. . Furthermore, in the handwriting input device that the inventor has already proposed, the writing implement 51 is set with the axis in the axial direction.
For example, when writing a straight line while rotating, the direction of the acceleration detected by the acceleration sensor 52 changes with the rotation. For this reason, although a straight line is written, the straight line is reproduced as writing information of a curve corresponding to the rotation, and it is preferable to improve this point.

[0005] The present invention has been made in view of the above problems, and has as its main object to provide an input device capable of accurately calculating writing information.

[0006]

According to a first aspect of the present invention, there is provided an input device comprising a writing implement and a processing unit for calculating writing information about the writing implement, wherein the writing implement is arranged in the axial direction of the writing implement. An acceleration sensor configured to detect each acceleration corresponding to two acceleration detection axes orthogonal to each other on an intersecting plane, and corresponding to two rotation angle detection axes orthogonal to each other on an intersection plane. An angular velocity sensor configured to detect each rotational angular velocity of the writing instrument, and the processing unit detects each rotational angle of the two acceleration detection axes before and after a very short time during the writing operation. Based on the rotational angular velocities, the respective accelerations respectively corresponding to the two acceleration detection axes detected after a very short time are calculated based on each of the obtained rotation angles at the minute time before. One of and calculates the handwritten information by converting corresponding to the acceleration in the acceleration detection axis.

According to a second aspect of the present invention, in the input device according to the first aspect, the acceleration sensor is further configured to be capable of detecting an acceleration corresponding to an acceleration detecting axis orthogonal to the two acceleration detecting axes. The angular velocity sensor is configured to further detect a rotational angular velocity of a writing implement corresponding to a rotation angle detection axis orthogonal to the two rotation angle detection axes, and the processing unit includes three acceleration detection axes extending before and after a minute time. Are obtained based on the detected rotational angular velocities, and the respective accelerations respectively corresponding to the three acceleration detection axes detected after a very short time are calculated based on the obtained rotational angular velocities. It is characterized in that the writing information is calculated by converting the acceleration into accelerations respectively corresponding to the three acceleration detection axes.

According to a third aspect of the present invention, in the input device according to the first or second aspect, each of the acceleration sensor and the angular velocity sensor has a direction of each rotation angle detecting axis and a direction of each acceleration detecting axis parallel to each other. It is characterized by being provided in a writing instrument such that

According to a fourth aspect of the present invention, in the input device according to any one of the first to third aspects, the processing unit comprises:
The tilt angle of the writing implement is calculated based on the accelerations respectively corresponding to the acceleration detection axes, and the writing information corresponding to the writing plane of the writing implement is calculated based on the inclination angle and the writing information.

[0010]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of an input device and a writing instrument according to the present invention will be described below with reference to the accompanying drawings.

As shown in FIG. 1, the input device 1 includes a writing instrument 2 and an input device main body 3. In this case, as shown in FIG. 2, the writing instrument 2 has a pen-like appearance and is formed in a hollow shape, and has an acceleration sensor 11 inside.
And an angular velocity sensor 12 are provided. The acceleration sensor 11 is an integrated circuit type three-dimensional acceleration sensor,
The acceleration corresponding to three directions of the X direction, the Y direction, and the Z direction is detected. In this case, the Z direction is parallel to the axial direction of the writing implement 2, the X direction and the Y direction are orthogonal to each other, and also orthogonal to the axial direction of the writing implement 2. The angular velocity sensor 12 detects an angular velocity using three line segments parallel to the X direction, the Y direction, and the Z direction in which acceleration is detected by the acceleration sensor 11 as rotation axes. Regarding the angular velocity due to the writing operation, the maximum value in the X-axis direction and the Y-axis direction is about 300 ° / s and the maximum value in the Z-axis direction is about 90 ° / s when writing characters with a size of 60 mm or less. The sensor 12 is configured by, for example, disposing one single-axis vibration type gyro (detection range ± 300 ° / s) one each in the X-axis direction, the Y-axis direction, and the Z-axis direction. The acceleration sensor 11 and the angular velocity sensor 12 are connected to the input device main body 3 via a signal output cable (not shown). On the other hand, the input device main body 3 includes a processing unit 21 and a writing implement 2.
And a display unit 22 for displaying a locus or the like written by the user.

The processing unit 21 includes A / D converters 31 and 32,
An arithmetic circuit 33, an FFT (Fast Fourier Transform) processing circuit 34, a writing state detection circuit 35, a recognition circuit 36, and a recognition data ROM 37 are provided. In this case, A /
The D converter 31 outputs the acceleration detection signal SX1 for the X direction, the acceleration detection signal SY1 for the Y direction, and the acceleration detection signal S for the Z direction, which are output from the acceleration sensor 11.
The analog-to-digital conversion of Z1 results in acceleration data D in the X direction at a predetermined sampling period.
X1 and acceleration data DY1 in the Y direction and acceleration data DZ1 in the Z direction are generated. Further, the A / D converter 32 outputs an angular velocity detection signal SX2 output from the angular velocity sensor 12 having a rotation axis in the X direction, an angular velocity detection signal SY2 having a rotation axis in the Y direction, and an angular velocity having a rotation axis in the Z direction. Detection signal S
By performing analog-digital conversion of Z2, the angular velocity data D in the X direction is obtained at a predetermined sampling cycle.
X2, angular velocity data DY2 in the Y direction and angular velocity data DZ2 in the Z direction are generated.

The arithmetic circuit 33 has a built-in digital low-pass filter, and based on acceleration data DX1, DY1, and DZ1 and angular velocity data DX2, DY2, and DZ2 input through the digital low-pass filter, a writing implement 2 described later. Parameter data DP as handwriting information
Is calculated. The FFT processing circuit 34 includes, for example, a DSP (Di
gital Signal Processor) and acceleration data D
The frequency components included in X1, DY1, and DZ1 are detected, and the detected frequency data DF is output to the writing state detection circuit 35. Based on the frequency data DF, the writing state detection circuit 35 generates a frequency band component of, for example, about 50 Hz generated when the writing implement 2 is brought into contact with the writing plane, by using the acceleration data DX.
It is determined whether it is included in any of 1, DY1, and DZ1. When the writing state detection circuit 35 determines that the frequency band component is included, the writing state detection circuit 35 outputs the determination signal SD that the writing implement 2 is in the writing state.

The recognition circuit 36 detects the start and end of writing of each image of a character or a symbol based on the rising edge and the falling edge of the discrimination signal SD output from the writing state detection circuit 35, respectively. Based on the result and the writing parameter data DP output from the arithmetic circuit 33, display data DDP for reproducing the trajectory of the character and symbol is generated and output to the display unit 22. The recognition circuit 36 recognizes the type of the character or the symbol by comparing the reproduced character symbol trajectory with the recognition data DW stored in the recognition data ROM 37 and specifying the character symbol trajectory for character symbol recognition. And a signature authentication process for authenticating whether or not the signature is correct. The recognition data ROM 37 stores recognition data DW for specifying various character symbols and signature writing trajectories for performing character symbol recognition and signature authentication.

Next, the calculation principle of the writing information calculation process for calculating writing information such as the amount of movement of the writing implement 2 on the detection plane and the writing plane based on the acceleration and the acceleration acting on the writing implement 2 in the input device 1 will be described. This will be described with reference to the drawings.

As a method of obtaining a moving trajectory from three-dimensional acceleration and three-dimensional angular velocity, there are an Euler method using an Euler angle, a method based on a quaternion method, and the like. In the embodiment of the present invention, a method for obtaining the movement locus (writing information) of the writing instrument 2 by the Euler method that is easy to understand intuitively will be described.

First, as shown in FIG. 3, when the writing implement 2 is written with rotation, three-dimensional coordinates with the axis length direction of the writing implement 2 at the start of the writing operation or at an arbitrary time point as the Z axis. When one sampling time has elapsed, the system (hereinafter, referred to as a “coordinate system”), as shown in FIG.
Change to a coordinate system with one axis as the axis. Here, the acceleration detected corresponding to the coordinate system XYZ one sampling time ago (before the movement) and the movement rotated by φ, θ, and Ψ around the X, Y, and Z axes of the coordinate system XYZ, respectively. Consider acceleration later on the coordinate system X1 Y1 Z1.
In this case, the coordinates of an arbitrary vector u on the coordinate system XYZ are (xyz) ^T (“T” in this case means transpose), and the coordinates of the vector u on the coordinate system X1 Y1 Z1 are When (x1 y1 z1) ^T , the vector u, which is the movement locus of the writing instrument 2 within one sampling time, has a relationship expressed by the following equation between the vector components on each coordinate system. In this case, the coordinates (xyz) ^{T of} the vector u and the acceleration sensor 11
Writing implement 2 based on the gravitational acceleration detected by
Is calculated in advance. In the equation, I means a unit matrix, and Ω means a rotation matrix.

(Equation 1)

In this case, by setting the sampling period at the time of data capture at each speed of the writing instrument 2 to, for example, 2 ms, the level of the angular velocity change per sample is less than 1 ° at the maximum. Therefore, if the rotation angle of the writing instrument 2 is small, the rotation matrix Ω in the Euler method is c
Since osα, sinα, and αβ (α and β are arbitrary small angles) are approximated by “1”, “α”, and “0”, respectively, they are replaced by equations. In the equation,
δφ, δθ, δΨ mean minute rotation angles with respect to φ, θ, Ψ, respectively. Further, each component of the rotation matrix Ω in the expression means a rotation angle corresponding to each axis, and is approximately equivalent to the angular velocity detected by the angular velocity sensor 12.

(Equation 2)

Further, the coordinate system XYZ is defined by a small angle X1.
.., XnYZn, n times, an arbitrary vector un detected in the coordinate system XnYnZn becomes the coordinate system XYZ as shown in the following equation.
It is converted to the upper coordinate u (n).

(Equation 3)

In the equation, R (n) is represented by the following equation, and the transformation matrix (R
(0) = I). In addition, Ω (n) is represented by the following equation and means a rotation matrix.

(Equation 4)

(Equation 5)

In this case, the rotation matrix Ω (n) is configured with the rate of change of each rotation angle, that is, the angular velocity corresponding to each axis as an element. Therefore, even if the coordinate system serving as the reference of the acceleration vector is rotated by the writing operation involving rotation, the coordinate system before the movement is determined based on the angular velocity corresponding to each axis detected by the angular velocity sensor 12 at each sampling time. It can be converted into an acceleration vector on XYZ.

On the other hand, when the writing implement 2 is performing a writing operation in a circular arc, the writing implement 2 is affected not only by gravitational acceleration and acceleration due to the writing operation but also by centrifugal acceleration. Therefore, to eliminate the effects of centrifugal acceleration,
Velocity vector v at any sampling point k
(K) is expressed by an equation using a difference equation. In addition,
In the equation, g (k) means a gravitational acceleration vector, which is obtained from the initial value of the gravitational acceleration by using an inverse matrix of the transformation matrix R (n). A (k) represents an acceleration vector based on the output of the acceleration sensor, and T represents a sampling time. Further, Ωv (k) means a transformation matrix used when obtaining the current speed in consideration of the centrifugal acceleration using the speed one sample before.

(Equation 6)

In this case, when the rotation angle of the writing instrument 2 is small and cos α ≒ 1, sin α ≒ α, and αβ ≒ 0, the following equation is established.

(Equation 7)

Therefore, if the position vector p (k) of the writing instrument 2 in the reference coordinate system XYZ is represented by a difference equation using the velocity vector v (k) obtained by the equation, it is represented by the equation. The second term on the right side means the moving distance of the writing implement 2 when the coordinates are the same.

(Equation 8)

Based on the position coordinate vector p (k) of the writing implement 2 obtained by the above processing and the inclination angle of the writing implement 2 calculated first, the writing information corresponding to the writing plane of the writing implement 2 is finally obtained. calculate. Specifically, the inclination angle of the detection plane with respect to the writing plane is calculated based on the inclination angle of the writing implement 2 at the start of writing, and then the position coordinate vector p of the writing implement 2 on the detection plane at the end of writing is calculated.
(K) is detected. Next, by converting the position coordinate vector p (k) on the detection plane at the end of writing into a position coordinate vector on the writing plane, the writing locus of the writing implement 2 from the start of writing on the writing plane to the end of writing. Can be reproduced.

Next, the overall operation of the input device 1 will be described.

First, when the acceleration sensor 11 and the angular velocity sensor 12 output the acceleration detection signals SX1, SY1, SZ1 and the angular velocity detection signals SX2, SY2, SZ2 at each sampling time, the A / D converters 31, 32 are activated. ,
Analog-digital conversion and acceleration data DX1, DY
1, DZ1 and angular velocity data DX2, DY2, DZ2. Next, the arithmetic circuit 33 converts the acceleration data DX1, DY1, DZ1 into acceleration data based on the coordinate system XYZ before movement based on the angular velocity data DX2, DY2, DZ2 according to the above-described calculation principle.

On the other hand, the FFT processing circuit 34 detects the frequency components included in the acceleration data DX1, DY1, and DZ1 and outputs the frequency data DF to the writing state detection circuit 35. Next, the writing state detection circuit 35 outputs the frequency data D
When it is determined that the writing implement 2 is in the writing state based on F, a determination signal SD is output to the arithmetic circuit 33.

Next, the arithmetic circuit 33 calculates the moving speed of the writing implement 2 by performing an integration process on the converted acceleration. In this case, the acceleration detection signals SX1, SY1, S
When noise is superimposed on Z1, the influence of noise on the operation result increases. Further, when the steady deviation is superimposed on the calculated acceleration, the influence of noise increases in proportion to time. Therefore, in the subsequent movement amount calculation, when noise is superimposed on the acceleration detection signals SX1, SY1, and SZ1, the influence of the noise increases in proportion to the time, and when the stationary deviation is superimposed. In the case of, the moving amount error included in the calculation result increases quadratically. Specifically, when each image of a character or a symbol is written, when the moving speed is calculated based on the acceleration detection signals SX1, SY1, and SZ1 on which noise is superimposed, the noise of the calculated moving speed waveform is obtained. Are accumulated. Therefore, the speed error increases in proportion to the time.

Therefore, when the discrimination signal SD is output from the writing state detection circuit 35, the arithmetic circuit 33 determines that the writing of each character or symbol is to be started, and determines the moving speed of the writing start of each image. Correct to 0 cm / s. More specifically, when the discrimination signals SD corresponding to the first to n-th strokes are sequentially input, the arithmetic circuit 33 sets the speed of the writing implement 2 at the start of writing each stroke to 0 cm / s. Is corrected. This is because the moving speed at the start of writing each image, that is, the moving speed when the writing implement 2 comes into contact with the paper surface or the like is 0 cm / s or a very low speed. The purpose is to match the moving speed.

In this correction processing, the arithmetic circuit 33 determines, for example, the moving speed corresponding to the first image (normally 0 cm / s), which is the operation result before correction, and the moving speed corresponding to the second image. Is calculated. In this case, the moving speed corresponding to the start of writing the first stroke to the moving speed corresponding to the start of writing the second stroke often increase in proportion to time. Therefore, the arithmetic circuit 33 calculates the moving speed error in the intermediate process of writing the two strokes from the time required from the writing start time of the first stroke to the writing start time of the second stroke, and from the writing start time of the first stroke. By subtracting the moving speed error due to noise from the moving speed before correction based on the elapsed time until each intermediate process and the moving speed difference at the start of writing the first and second strokes, Is calculated. Thereby, the moving speed is corrected.

Next, the arithmetic circuit 33 calculates the moving amount of the writing implement 2 by integrating the corrected moving speed. After that, the arithmetic circuit 33 writes the writing parameter data DP including the acceleration, the moving speed, and the moving amount of the writing implement 2.
Is output to the recognition circuit 36. On the other hand, the recognition circuit 36 reproduces the writing locus based on one or more of the acceleration, the moving speed and the moving amount of the writing parameter data DP, and recognizes the reproduced writing locus and the recognition data ROM 37. By comparing the data with the data DW, character / character recognition processing and signature authentication processing are executed.

As described above, according to the input device 1, when a writing operation involving rotation is performed, the detection signal of the acceleration sensor 11 is converted into a coordinate system before rotation based on the angular velocity detected by the angular velocity sensor 12. By converting the acceleration into a corresponding acceleration, the written trajectory can be accurately reproduced. In addition, according to the input device 1, the writing implement 2 includes the acceleration sensor 11 that can detect acceleration in a direction (Z direction) along the axial direction. Even in the case of moving in a different direction, the writing trajectory can be accurately reproduced.

The present invention is not limited to the configuration shown in the above-described embodiment of the present invention. For example, in the embodiment of the present invention, an example in which the three-dimensional acceleration sensor 11 and the angular velocity sensor 12 are used has been described. However, the embodiment may be configured using a two-dimensional acceleration sensor and an angular velocity sensor. According to this configuration, the writing trajectory when the writing implement 2 rotates with the X-axis and Y-axis directions as rotation axes can be accurately reproduced. Also, a configuration is adopted in which the direction of each acceleration detection axis (X, Y, Z) of the acceleration sensor 11 and the direction of each rotation angle detection axis (X, Y, Z) of the angular velocity sensor 12 are not parallel to each other. Even when such a configuration is adopted, the non-parallelism of each axis can be corrected by calculation. However, if a configuration is adopted in which the direction of each acceleration detection axis of the acceleration sensor 11 and the direction of each rotation angle detection axis of the angular velocity sensor 12 are parallel to each other, the correction processing may be unnecessary. Since it is possible, the calculation of the handwritten information becomes easy. In addition, the present invention is not necessarily applied to the case where the writing implement is written on a writing plane, and can be applied to an input device that calculates three-dimensional writing information when the writing implement is written in the air.

Further, the example in which the acceleration sensor 11 and the angular velocity sensor 12 are arranged vertically in the axial direction has been described, but the arrangement positions of the acceleration sensor 11 and the angular velocity sensor 12 are not limited to this. In this case, the acceleration sensor 1
By making the acceleration detection direction 1 and the angular velocity detection axis of the angular velocity sensor 12 parallel to each other, the calculation of the movement amount of the writing implement 2 becomes easy. Further, in the embodiment of the present invention, an example has been described in which the processing unit 21 is configured by a digital circuit, but various filters and the like may be of an analog type. Further, the FFT processing circuit 34
It is needless to say that a high-pass filter or a band-pass filter can be adopted in place of the above. Furthermore, an example in which both the acceleration sensors 11 and 12 and the input device main body 3 are connected by a signal output cable has been described. Further, the present invention is not limited in its use, and can be applied to, for example, various input devices such as a measuring device.

[0036]

As described above, according to the input device of the first aspect, the acceleration sensor configured to detect each acceleration corresponding to each of the two acceleration detection axes and the two rotation angle detection axes are provided. An angular velocity sensor configured to be able to detect each rotational angular velocity of the writing implement corresponding to each of the axes, the writing implement is configured, and the processing unit performs two accelerations before and after a minute time based on each detected rotational angular velocity. Each rotation angle of the detection axis is obtained, and each acceleration corresponding to each of the two acceleration detection axes detected after a very short time is calculated based on each rotation angle. By converting the acceleration into the acceleration and calculating the writing information, the writing locus of the writing implement can be accurately reproduced.

According to the input device of the second aspect,
The acceleration sensor detects acceleration corresponding to the three acceleration detection axes, the angular velocity sensor further detects the rotational angular velocities of the writing implement corresponding to the three rotation angle detection axes, and the processing unit detects each of the detected rotations. The rotation angles of the three acceleration detection axes before and after the minute time are obtained based on the angular velocities, and the respective accelerations respectively corresponding to the three acceleration detection axes detected after the minute time are calculated before the minute time based on the respective rotation angles. Accurately reproduces the writing trajectory even when the writing implement moves in the direction along the axial length by calculating the writing information by converting the acceleration into the accelerations corresponding to the three acceleration detection axes. can do.

Further, according to the input device of the present invention, the acceleration sensor and the angular velocity sensor are provided on the writing instrument such that the directions of the rotation angle detecting axes and the acceleration detecting axes are parallel to each other. This eliminates the need for the correction processing for correcting the non-parallelism of each axis, thereby facilitating the calculation processing of the writing information.

According to the writing implement of the fourth aspect, the processing section calculates the inclination angle of the writing implement based on each acceleration corresponding to each of the two acceleration detecting axes, and based on the inclination angle and the writing information. By calculating the writing plane writing information corresponding to the writing plane of the writing implement, the writing information when writing on the writing plane can be accurately calculated.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a configuration of an input device 1 according to an embodiment of the present invention.

FIG. 2 is an external perspective view of a writing instrument 2 in the input device 1.

FIG. 3 is an explanatory diagram illustrating an example of a writing operation of the writing implement 2.

4 is a coordinate system diagram showing a relationship between a coordinate system XYZ before movement with the axis length direction of the writing implement 2 as a Z axis and a coordinate system X1 Y1 Z1 after movement in the writing operation of FIG. 3;

FIGS. 5A and 5B are side views of a handwriting input device already proposed by the inventor, wherein FIG. 5A is a side view of the writing instrument 51 at the start of a writing operation, and FIG. It is a side view of 51.

[Explanation of symbols]

 Reference Signs List 1 input device 2 writing implement 3 input device main body 11 acceleration sensor 12 angular velocity sensor 21 processing unit 33 arithmetic circuit

Continuation of the front page F term (reference) 5B068 AA04 AA36 BD12 BD17 BE08 CC17

Claims (4)

[Claims] 1. A writing instrument, comprising: a processing unit that calculates writing information about the writing instrument, wherein the writing instrument has two acceleration detection axes orthogonal to each other on an intersecting plane that intersects the axis direction of the writing instrument. An acceleration sensor configured to detect each corresponding acceleration, and an angular velocity sensor configured to detect each rotational angular velocity of the writing implement corresponding to two rotational angle detection axes orthogonal to each other on the intersection plane. The processing unit is configured to determine each rotation angle of the two acceleration detection shafts before and after a minute time during the writing operation based on the detected rotation angular velocities, and The respective accelerations respectively corresponding to the two acceleration detection axes detected later are calculated based on the obtained rotation angles and the two accelerations before the minute time. Input apparatus characterized by calculating the handwritten information by converting each time the detection axis corresponding to the acceleration. 2. The acceleration sensor according to claim 1, wherein said acceleration sensor is configured to further detect an acceleration corresponding to an acceleration detection axis orthogonal to said two acceleration detection axes, and said angular velocity sensor is connected to said two rotation angle detection axes. The rotation angular velocity of the writing implement corresponding to the orthogonal rotation angle detection axis is configured to be further detectable, and the processing unit is configured to detect the rotation angles of the three acceleration detection axes before and after the minute time. Based on the rotational angular velocities, the respective accelerations respectively corresponding to the three acceleration detection axes detected after the minute time are calculated based on the determined rotational angular velocities. 2. The input device according to claim 1, wherein the writing information is calculated by converting the writing information into accelerations respectively corresponding to the detection axes. 3. The writing instrument according to claim 1, wherein the acceleration sensor and the angular velocity sensor are arranged on the writing implement such that directions of the rotation angle detection axes and directions of the acceleration detection axes are parallel to each other. The input device according to claim 1 or 2, wherein 4. The processing unit calculates an inclination angle of the writing implement based on the accelerations respectively corresponding to the two acceleration detection axes, and calculates the inclination angle of the writing implement based on the inclination angle and the writing information. 4. The input device according to claim 1, wherein writing information corresponding to a writing plane is calculated.