JP5272401B2 - Handwriting handwriting input system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve problems that in a conventional handwriting input system in which when the writing speed of a pen is suddenly increased after it is reduced, accurate handwriting cannot be reproduced since change in transmission output or repeated transmission interval of ultrasonic wave cannot catch up the sudden change in speed of the pen. <P>SOLUTION: In the handwriting input system, an electronic pen has an acceleration sensor, and repeated transmission intervals of infrared signal and ultrasonic signal are controlled depending on the magnitude of the acceleration detected thereby so that position coordinate data is obtained in detail in a place having large acceleration while the position coordinate data is obtained efficiently in a place having small acceleration. According to this, the repeated transmission intervals can respond to a sudden change in moving speed of the electronic pen, and the handwriting input system can have good reproducibility of handwriting and attain power saving. <P>COPYRIGHT: (C)2009,JPO&amp;INPIT

Description

  The present invention includes an electronic pen that transmits at least an infrared signal and an ultrasonic signal, and means for receiving the infrared signal and the ultrasonic signal and calculating a position coordinate of the electronic pen from the arrival time difference thereof About the system.

Conventionally, a position detection technique of an electronic pen using an infrared signal or an ultrasonic signal is known. For example, in Japanese Patent Application Laid-Open No. Sho 62-175721 (see Patent Document 1) and US Pat. No. 4,814,552 (see Patent Document 2), an ultrasonic signal or an infrared signal and an ultrasonic wave are transmitted from an electronic pen. A technique is disclosed in which signals are generated, those signals are received by a receiving unit, and the position coordinates of the electronic pen are calculated based on the time of flight of the ultrasonic signal.

  A handwritten handwriting input system using these position detection techniques is, for example, as follows. A writer writes characters and figures using an electronic pen. At this time, the electronic pen may incorporate a ballpoint pen, for example, so that a recording medium such as paper may be used as a writing surface, and handwriting may be recorded on the recording medium. The electronic pen may include a stylus, for example. Any surface including the surface of the liquid crystal display may be used as a writing surface. At least while the pen tip of the electronic pen is in contact with the writing surface, infrared signals and ultrasonic signals are repeatedly transmitted from the electronic pen, and the receiving unit receives the infrared signals and ultrasonic signals transmitted from the electronic pen. Then, the flight time of the ultrasonic signal is measured from the difference between the arrival time of the infrared signal and the arrival time of the ultrasonic signal, and the coordinate calculation unit calculates the position coordinate data of the electronic pen from the flight time of the ultrasonic signal.

In the conversion from position coordinate data to handwriting data, information expressing features such as handwriting data derived from the handwriting written by the writer is added to the position coordinate data, or individual positions based on these features are added. This refers to processing for modifying the coordinate data, and includes, for example, any of the following processing. Information on the time when the position coordinate data is received is added. Based on the acquisition interval of the position coordinate data, the writing speed is calculated, or a set of position coordinates is identified as one stroke data including the writing order and speed as information. The continuous position coordinate data constituting one stroke data is corrected so as to draw a smooth line. Further, based on conditions such as extraction and integration of circumscribed rectangles of stroke data and restriction of writing position, the stroke data is grouped into character group data including information such as the order of writing.

The handwriting data input by the handwriting handwriting input system is displayed on the screen of an electronic device, used as code data through character recognition processing, etc., or writing such as handwriting shape, speed of handwriting, stopping, splashing, and brushing. It may be used for arbitrary purposes such as extracting the characteristics of a writer's character including characteristics and signature verification. Moreover, if it is the structure which supplies a power supply to the whole handwriting handwriting input system, the use will be possible outdoors and a use application will increase significantly. In addition, when used in combination with character recognition conversion software that converts handwriting data into character data for use in a word processor, etc., it can be used as an input means that can easily input characters, pictures, symbols, etc. by hand as well as character data. Attention has been paid.

Since handwriting data is converted based on the value of position coordinate data, the repeated transmission interval of infrared and ultrasonic waves transmitted from the electronic pen is shortened, and the more detailed the position closer to the actual handwriting, the more the number of position coordinate data. Information can be obtained and handwriting can be accurately reproduced. However, in consideration of portability and ease of writing, the electronic pen should be a wireless system. If the repeated transmission interval of infrared rays and ultrasonic waves is shortened, the power consumption of the electronic pen increases and continuously. The usable time will be shortened.

As a method for reducing pen power while maintaining reproducibility of handwriting data, Japanese Patent Application Laid-Open No. 2004-102896 discloses that a pen and a receiver have bidirectional signal notification means, and the receiver calculates the position coordinates of the pen. . Based on the state at that time, an apparatus has been disclosed in which the pen reduces the power consumption of the pen by changing the transmission output of infrared and ultrasonic waves and the repeated transmission interval of infrared and ultrasonic waves.

JP-A-62-175821 U.S. Pat. No. 4,814,552 JP 2004-102896 A

However, the above-mentioned Patent Document 3 informs the pen of the value after the receiver calculates the position coordinate of the pen, and then the pen changes the transmission output or the repeated transmission interval based on the position coordinate and the moving speed. Therefore, it may react with a delay from the actual writing action. For example, if the writing speed of the pen is slowed down and then suddenly increased, changes in the ultrasonic transmission output and repeated transmission interval cannot catch up with the rapid speed change of the pen, and accurate handwriting cannot be reproduced.
The present invention has been made in order to solve the above-mentioned problems. While the position coordinate data is obtained in detail when the acceleration is large, the position coordinate data is efficiently obtained when the acceleration is small. An object of the present invention is to realize a handwriting handwriting input system that can cope with a change in the moving speed of the handwriting, has good reproducibility of handwriting, and can save power.

At least an infrared transmission circuit including an infrared generation element, an ultrasonic transmission circuit including an ultrasonic generation element, and a means for detecting acceleration, and repeating infrared signals and ultrasonic signals from the infrared transmission circuit and the ultrasonic transmission circuit An electronic pen comprising: a signal transmission unit for transmitting; a writing unit having a function capable of directly leaving a locus on a recording medium; and a pen switch for determining whether or not the writing unit is in a writing state; At least one infrared receiving unit having a function of receiving the infrared signal, two or more ultrasonic receiving units having a function of receiving the ultrasonic signal, the infrared signal and the ultrasonic signal. A signal receiving unit having a receiving circuit for detecting reception, and the electronic pen and the ultrasonic receiving unit from the arrival time difference between the infrared signal and the ultrasonic signal Handwritten handwriting comprising: a coordinate calculation unit that calculates a distance and calculates the position coordinate data of the electronic pen using the distance; and a conversion processing unit that has a function of converting the position coordinate data of the electronic pen into handwriting data In the input system, when the acceleration applied to the electronic pen increases , the signal transmission unit shortens the repeated transmission interval of the infrared signal and the ultrasonic signal, and when the acceleration decreases, the infrared signal And a handwritten handwriting input system for prolonging the repeated transmission interval of the ultrasonic signals .

In the handwritten handwriting input system according to the present invention, when the acceleration applied to the electronic pen is large, the repeated transmission interval of infrared rays and ultrasonic waves is shortened so that the position coordinates such as the position where the writing direction is changed and the wrinkle part at the time of writing are obtained. Many can be acquired and accurate handwriting can be reproduced.

If more accurate handwriting data is to be obtained, it is better to shorten the interval between repeated transmissions of infrared rays and ultrasonic waves of the electronic pen. However, the power consumption of the electronic pen increases accordingly. When the acceleration applied to the electronic pen is small, the handwriting handwriting input system of the present invention reduces the power consumption of the electronic pen without reducing the reproducibility of the handwriting by increasing the repeated transmission interval of infrared and ultrasonic waves. Can do.

In the handwritten handwriting input system of the present invention, when the acceleration applied to the electronic pen is large, the repeated transmission interval of infrared and ultrasonic waves is shortened. When the acceleration applied to the electronic pen is small, the repetition of infrared and ultrasonic waves is performed. Since the signal transmission unit in the electronic pen controls so that the transmission interval becomes longer, it is possible to cope with a rapid change in the electronic pen speed, accurately reproduce the characteristics of the handwriting, and to save power.

DESCRIPTION OF EXEMPLARY EMBODIMENTS Hereinafter, a preferred embodiment of a handwriting handwriting input system according to the invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a perspective view showing an example of a handwritten handwriting input system according to the present embodiment. In the figure, a receiver 2 includes two ultrasonic receiving units, an infrared ultrasonic measuring unit having an infrared receiving unit and a receiving circuit, a coordinate calculation unit for calculating position coordinate data of an electronic pen, and handwriting the position coordinate data. Consists of components of a conversion processing unit that converts data. The receiver 2 is connected to the computer 6 via the communication interface 5, and the handwriting data of the electronic pen 1 is transmitted from the conversion processing unit of the receiver 2 to the computer 6, so that the computer 6 is mounted on the mounted display. A handwriting can be displayed, a character recognition process can be performed, or it can be stored in a storage device.

  The structure of the electronic pen 1 will be described with reference to the block diagram of the electronic pen in FIG. The basic configuration of the electronic pen 1 includes an ultrasonic transmission circuit 11 that can transmit an ultrasonic signal by the ultrasonic generation element 10, an infrared transmission circuit 9 that can transmit an infrared signal by the infrared generation element 8, and an acceleration. The sensor 12, the signal transmission unit 13 that controls the interval at which the ultrasonic signal and the infrared signal are repeatedly transmitted based on the measurement value of the acceleration sensor 12, the writing unit 3 of the pen tip, and the writing unit 3 are connected to the recording medium 4. In consideration of portability and ease of writing, the pen switch 14 can be turned on / off according to the writing state and non-writing state when drawing characters and drawings while touching, so that it can be used wirelessly. The battery 15 supplies power to the entire electronic pen. In the present embodiment, the writing unit 3 is a ballpoint pen or a mechanical pencil provided with a function capable of directly leaving a locus on the recording medium 4. For example, the writing unit 3 has a built-in stylus and the surface of the display. Any surface including the above may be used as a writing medium.

For example, an LC resonance circuit unit including a capacitor, a coil, and an ultrasonic generation element 10 is disposed inside the ultrasonic transmission circuit 11, and a piezoelectric element is used as the ultrasonic generation element 10. The shape of this piezo element is often cylindrical. This is because it is preferable that the piezo element of the electronic pen 1 transmits an ultrasonic signal uniformly in any direction on the recording medium 4 regardless of the direction in which the writer uses the electronic pen 1. It is. In this configuration, the cylindrical piezo element itself also has a resonance frequency. At this time, it is preferable to adjust the configuration of the resonance frequency f ₀ of the LC resonance circuit unit as close as possible to the resonance frequency of the piezoelectric element. The resonance frequency of a piezo element is determined by the characteristics of the piezo film and the diameter of the cylinder, and the ultrasonic wave has a lower attenuation with distance, while the higher the frequency, the higher the coordinate resolution. To determine the resonance frequency. In the case of a handwritten handwriting input system using an electronic pen, the frequency is preferably about several tens of kHz, and around 80 kHz is preferably used.

A transistor or FET and an infrared generation element 8 are arranged inside the infrared transmission circuit 9, and transmission of the infrared generation element 8 can be turned on or off by controlling the transistor or FET. At this time, it is preferable to arrange a plurality of the infrared ray generating elements 8 in consideration of the directivity angle so that infrared rays are transmitted in all directions with respect to the cylindrical axis of the electronic pen 1.

The acceleration sensor 12 may be small, highly sensitive, and has good linearity with respect to acceleration. Any one of a piezoelectric acceleration sensor, a piezoelectric acceleration sensor, or a capacitance acceleration sensor may be used. May be.
The acceleration sensor 12 needs to be able to detect at least two axes of the X axis and the Y axis that are orthogonal to the pen axis direction. In consideration of the inclination of the electronic pen during writing with respect to the writing surface, the Z axis is the pen axis direction. It is possible to measure more accurately by selecting one that can be detected in the three-axis direction including Moreover, it is preferable to install it at a position as close to the pen tip as possible.

The signal transmission unit 13 of the electronic pen 1 stores the measurement interval of the acceleration sensor 12 in advance, and the repetition transmission interval of the infrared signal and the ultrasonic signal corresponding to the value calculated from the measurement value of the acceleration sensor 12. Also record the table. At least while the writing unit 3 of the electronic pen 1 is in contact with the recording medium 4 and is in the writing state, the pen switch 14 is turned on. At the moment when the pen switch 14 is turned on from off, the signal transmission unit 13 transmits an infrared signal and an ultrasonic signal, and at the same time, the acceleration sensor 12 starts measurement at a predetermined interval. At this time, the value of the acceleration sensor 12 measured first is recorded in the signal transmission unit 13 as an initial value, and the corresponding infrared signal and ultrasonic wave are calculated by correcting the measured value of the acceleration sensor 12 measured next with the initial value. Sends signals at repeated signal transmission intervals. Thereafter, the position coordinate of the electronic pen 1 in the writing state can be obtained by repeatedly transmitting the transmission value of the infrared signal and the ultrasonic signal with the value obtained by correcting the measurement value of the acceleration sensor 12 with the initial value. it can. When the writing unit 3 of the electronic pen 1 is separated from the recording medium 4 and the writing state is finished, the pen switch 14 is changed from on to off, and the transmission of the infrared signal and the ultrasonic signal and the measurement of the acceleration sensor 12 are also finished. The initial value of the acceleration sensor is also deleted.

Since the acceleration sensor needs to consider the direction of gravitational acceleration, the measurement value of the acceleration sensor when the pen switch is turned on is taken as the initial value, and the measurement value of the subsequent acceleration sensor is corrected so that the electronic pen can be The influence of gravity due to the orientation of the electronic pen and the tilt of the electronic pen when writing can be eliminated. In the case of a normal handwriting handwriting input system, one stroke, that is, from when the pen switch is turned on until it is turned off, is corrected with the measured value of the acceleration sensor at the moment when the pen switch is turned on as the initial value. Although it does not cause a big problem, when a large picture in which the tilt of the electronic pen changes during one stroke is frequently written, a geomagnetic sensor and an angular velocity sensor may be used in combination with the acceleration sensor. In other words, by measuring the acceleration applied to the electronic pen and simultaneously measuring the posture and rotation of the electronic pen, it is possible to accurately measure changes in the tilt and rotation of the electronic pen during one stroke, and more accurately measure the acceleration applied to the electronic pen. Can be measured.

The shorter the measurement interval of the acceleration sensor 12, the better the writing speed, and the repeater transmission interval can be controlled. The power for measuring the acceleration is much smaller than the power consumed to transmit the infrared signal and the ultrasonic signal. In the case of a handwritten handwriting input system capable of reproducing an accurate handwriting, the measurement interval of the acceleration sensor 12 may be set longer in the case of a system in which the measurement interval of the acceleration sensor 12 is shortened and power consumption is reduced.

The shorter the repeat transmission interval between the infrared signal and the ultrasonic signal, the more position coordinates per unit time can be transmitted and more detailed handwriting information can be obtained, but the power consumption of the electronic pen increases. The repeated transmission interval between the infrared signal and the ultrasonic signal changes the repeated transmission interval between the infrared signal and the ultrasonic signal according to the measurement value of the acceleration sensor while the pen switch is on.
For example, when the acceleration increases, the repetition interval between the infrared signal and the ultrasonic signal is shortened in inverse proportion to the value. On the other hand, when the acceleration decreases, it is preferable to increase the repetition interval of the infrared signal and the ultrasonic signal in inverse proportion to the value. At this time, the upper limit value of the repeated transmission interval may be set to 10 ms and the lower limit value 100 ms.
For example, when an acceleration of a certain value or more is measured, the repeated transmission interval between the infrared signal and the ultrasonic signal may be set to 10 ms, and 20 ms when the acceleration becomes a certain value or less.

When a triaxial acceleration sensor is used, three-direction acceleration components are output as measured values. If the initial values of the acceleration sensor are x ₀ , y ₀ , and z ₀ in the x direction, y direction, and z direction, respectively, and the newly measured acceleration sensor values are x ₁ , y ₁ , and z ₁ , the acceleration applied to the electronic pen The size d can be calculated by Equation 1.

When the value of d is large, it can be determined that the writing speed suddenly increases or decreases, or the position in which the writing direction changes greatly. Since the handwriting changes greatly in this state, the signal transmission unit can reproduce the accurate handwriting by shortening the repeated transmission interval of infrared rays and ultrasonic waves.

When the value of d is small, it can be determined that the electronic pen is in a stationary state or in a constant velocity linear motion. Since there is little change in handwriting in this state, the signal transmission unit can reduce the power consumption without degrading the reproducibility of the handwriting by increasing the repeated transmission interval of infrared rays and ultrasonic waves.
Although it is unlikely to occur in actual writing, if acceleration is continuously applied in the direction of travel or vice versa during writing, the handwriting becomes a straight line and the value of d is relatively large although there is little change in the handwriting. In some cases, the interval between repeated transmissions of sound waves is shortened and power consumption is not reduced.

Next, the structure of the receiver 2 will be described with reference to an internal block diagram of the receiver of FIG. The receiver 2 includes an infrared wave receiving unit 30, ultrasonic receiving units 31, 32, an amplifier 33, a filter circuit unit 36, a comparator 41, an infrared receiving circuit 54, amplifiers 34, 39, a filter circuit unit 37, and a comparator. 42, an infrared ultrasonic measurement unit 44 having an ultrasonic reception circuit 56 including an amplifier 35, 40, a filter circuit unit 38, and a comparator 43, a CPU 45, a timer 46, a flash memory 47, and a RAM 48. A coordinate calculation unit 49, a CPU 50, a conversion processing unit 52 including a RAM 51, a communication interface 5 for connecting to the computer 6, and a battery 53 capable of supplying power to the entire receiver 2. . It is better to install the ultrasonic receiving circuits 55 and 56 by the number of ultrasonic receiving units so that the ultrasonic receiving units 3 1 and 32 can perform processing even if they simultaneously receive ultrasonic signals. In the present embodiment, the coordinate calculation unit 49 and the conversion processing unit 52 are described separately by function, but the CPU and RAM of the coordinate calculation unit 49 and the conversion processing unit 52 may be common.

The infrared receiving unit 30 is provided with an infrared receiving element and receives an infrared signal emitted from the infrared generating element 8 of the infrared transmitting circuit 9 of the electronic pen 1. For this reason, the wavelength of the infrared receiving element is preferably the same as the wavelength of the infrared generating element 8.
The ultrasonic receiving units 31 and 32 are configured by the same ultrasonic generating element 10 inside the ultrasonic transmission circuit 11 of the electronic pen 1 and receive an ultrasonic signal transmitted from the ultrasonic transmission circuit 11. To do. The receiver 2 is provided with an opening so that an ultrasonic signal transmitted from the electronic pen 1 can be received without being blocked.

Infrared signal reception will be described. The infrared signal received by the infrared receiver 30 is amplified by the amplifier 33 and sent to the filter circuit 36. Even when external noise is received, the filter circuit unit 36 is preferably a filter that allows a signal in the same frequency band as the infrared signal received by the electronic pen 1 to pass through the external noise part. For example, when the wavelength of the infrared light emitting element 8 of the electronic pen 1 is 940 nm, a band pass filter having a peak at a wavelength of 940 nm may be designed. Thereafter, when the comparator 41 receives a signal that is equal to or greater than a predetermined threshold value, the CPU 45 of the coordinate calculation unit 49 reads the current time from the timer 46 when the comparator 41 detects the signal, and this time is read by infrared rays. It is stored in the RAM 48 as the signal arrival time.

Since the circuit configurations of the ultrasonic receiving circuits 55 and 56 are the same, description will be made using the ultrasonic receiving unit 31 and the ultrasonic receiving circuit 55. The ultrasonic reception unit 31 receives the ultrasonic signal, the amplifier 34 amplifies the signal, and sends it to the filter circuit unit 37. Even when the external noise is received, the filter circuit unit 37 is preferably a filter that allows a signal in the same frequency band as the ultrasonic signal transmitted by the electronic pen 1 to pass through so that the external noise portion can be blocked. For example, when the resonance frequency of the electronic pen is 80 kHz, a band pass filter having a peak at a frequency of 80 kHz may be designed. After that, the signal is amplified again by the amplifier 39, so that the rising edge becomes steeper and the head of the signal can be accurately identified. Thereafter, the comparator 42 detects the reception of a signal equal to or greater than a specific threshold value, and transmits a timing signal to the CPU 45 of the coordinate calculation unit 49. When detecting the timing signal sent from the comparators 42 and 43, the CPU 45 of the coordinate calculation unit 49 reads the current time from the timer 46 and stores this time in the RAM 48 as the arrival time of the ultrasonic signal.

Then, the CPU 45 of the coordinate calculation unit 49 determines the arrival time difference between the arrival time of the infrared signal in the infrared reception unit 30 stored in the RAM 48 and the arrival time of the ultrasonic signal in the two ultrasonic reception units 31 and 32 and the sound speed. Is used to calculate the distance from the electronic pen 1 to the ultrasonic receivers 31 and 32. The position coordinates of the electronic pen 1 are calculated using the theory of trigonometry, assuming a triangle with the positions of the electronic pen 1 and the two ultrasonic receivers 31 and 32 as vertices. The CPU 45 stores the calculated position coordinate data of the electronic pen 1 in the RAM 51 of the conversion processing unit 52.

  The CPU 50 of the conversion processing unit 52 recognizes the position coordinate data of the electronic pen 1 stored in the RAM 51 as stroke data of a series of aggregates based on the coordinate acquisition interval. The continuous position coordinate data constituting the stroke data is connected and corrected so as to draw a smooth line, and is transmitted to the computer 7 as handwriting data. In this embodiment, writing is performed while connected to the computer 7, but the communication interface 6 and the computer 7 are disconnected from the receiver 2, and the receiver 2 uses the power of the battery 53 to connect the computer 7 such as outdoors. Can be used where there is no place. In this case, the position coordinate data may be left in the RAM 51 of the conversion processing unit 52, or the data converted into handwriting data may be left. When the receiver 2 is connected to the computer 7 again, the CPU 50 of the conversion processing unit 52 transmits the data in the RAM 51 to the computer 7.

Example 1
Hereinafter, the present invention will be described with reference to examples and comparative examples. The present invention is not limited to the following examples, and includes various modifications within the technical scope of the present invention.
In Example 1, the handwriting handwriting input system arranged as shown in FIG. 1 was used. However, the resonance frequency of the ultrasonic transmission unit 11 of the electronic pen 1 was set to 80 kHz, and the measurement interval of the acceleration sensor was set to 15 ms. Based on the acceleration sensor, the transmission interval of the infrared signal and the ultrasonic signal is set to 50 ms when the acceleration is 30 mm / s ² or less, and 15 ms when the acceleration is 300 mm / s ² or more. During that time, the transmission interval is set in inverse proportion to the magnitude of the acceleration.
The filter circuit unit 35 is a band pass filter having a peak at 940 nm. Similarly, the filter circuit unit 35 is a band pass filter having a peak at 80 kHz. The receiver 2 and the computer 7 were disconnected, and the receiver 2 was used using the power of the internal battery 53.
Using the electronic pen 1, I wrote the time of Hiragana "A". The number of position coordinates constituting the character at this time was 83 points.

(Example 2)
In Example 2, the handwriting handwriting input system arranged as shown in FIG. 1 was used. However, the resonance frequency of the ultrasonic transmitter 11 of the electronic pen 1 was set to 80 kHz, and the measurement interval of the acceleration sensor was set to 5 ms. Based on the acceleration sensor, the transmission interval of the infrared signal and the ultrasonic signal is 50 ms when the acceleration is 30 mm / s ² or less, and 5 ms when the acceleration is 300 mm / s ² or more. During that time, the transmission interval is set in inverse proportion to the magnitude of the acceleration.
The filter circuit unit 35 is a band pass filter having a peak at 940 nm. Similarly, the filter circuit unit 35 is a band pass filter having a peak at 80 kHz. The receiver 2 and the computer 7 were disconnected, and the receiver 2 was used using the power of the internal battery 53.
Using the electronic pen 1, the writing time of Hiragana “A” was written at the same writing speed as in Example 1. The number of position coordinates constituting the character at this time was 120 points.

(Comparative Example 1)
In Comparative Example 1, the handwriting handwriting input system arranged as shown in FIG. 1 was used. However, the acceleration sensor is not used in the electronic pen.
The resonance frequency of the ultrasonic transmission unit 11 of the electronic pen 1 was set to 80 kHz, and the repetition transmission interval between the infrared signal and the ultrasonic signal of the signal transmission unit 12 was set to 15 ms. The filter circuit unit 35 is a band pass filter having a peak at 940 nm. Similarly, the filter circuit unit 35 is a band pass filter having a peak at 80 kHz. The receiver 2 and the computer 7 were disconnected, and the receiver 2 was used using the power of the internal battery 53.
Using the electronic pen 1, the writing time of Hiragana “A” was written at the same writing speed as in Example 1. The number of position coordinates constituting the character at this time was 144 points.

(Comparative Example 2)
In Comparative Example 2, the receiver transmits an infrared signal toward the electronic pen, and the electronic pen transmits an ultrasonic signal toward the receiver when receiving the infrared signal. The receiver is a handwriting handwriting input system that calculates the position coordinates of the electronic pen from the transmission time of the infrared signal and the reception time of the ultrasonic wave. The receiver calculates the position coordinates of the pen and converts the position coordinates into the infrared signal. Encode and notify the electronic pen. The electronic pen calculates the writing speed from the position coordinates, and changes the repeated transmission interval of the ultrasonic wave based on the writing speed. The repeated transmission interval at this time is 30 ms when the writing speed is 0 to 2 mm / s, 20 ms when the writing speed is 1 to 20 mm / s, and the repeated transmission interval when 20 mm / s or more. 10 ms.
Using the electronic pen, the same “Hi” time of hiragana as in Example 1 was written. The number of position coordinates constituting the character at this time was 94 points.

Example 1 and Comparative Example 2 were less than Comparative Example 1 in comparison with the number of constituents of characters written by the handwriting handwriting input system of Example 1, Comparative Example 1 and Comparative Example 2. The power used for the acceleration sensor measurement and the two-way communication between the electronic pen and the receiver is much less than the power consumed when transmitting infrared and ultrasonic signals. Therefore, both Example 1 and Comparative Example 2 are in terms of power consumption. It was confirmed that it was effective. However, when the character shapes of Example 1 and Comparative Example 2 are compared, Comparative Example 2 has a handwriting that is different from the actual handwriting at the bent portion of the character as shown in FIG. In the case of the first embodiment, the signal transmission unit measures the acceleration, and the repetition transmission interval of the infrared signal and the ultrasonic signal is changed based on the measured value. On the other hand, in the case of the comparative example 2, since the position coordinate of the electronic pen is calculated by the receiver and converted into the writing speed by the electronic pen, the interval for repeatedly transmitting the ultrasonic signal is changed. This is because the response of the repeated transmission interval to the writing speed is not good.
Further, when Example 2 and Comparative Example 1 are compared, although the number of constituent points of the position coordinates is almost the same, Example 2 shows the characteristics of the handwriting more accurately. From the above, it was confirmed that the present invention is effective.

Perspective view of handwriting handwriting input system Electronic pen block diagram Block diagram of a receiver in an embodiment Comparison diagram of handwriting data of examples and comparative examples

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic pen 2 Receiver 3 Writing part 4 Recording medium 5 Communication interface 6 Computer 8 Infrared generating element 9 Infrared transmitting circuit 10 Ultrasonic generating element 11 Ultrasonic transmitting circuit 12 Acceleration sensor 13 Signal transmitting part 14 Pen switch 15, 53 Battery 30 Infrared receiver 31, 32 Ultrasonic receiver 33, 34, 35, 39, 40 Amplifier 36, 37, 38 Filter circuit 41, 42, 43 Comparator 44 Infrared ultrasonic measuring unit 45, 50 CPU
46 Timer 47 Flash memory 48, 51 RAM
49 Coordinate calculation unit 52 Conversion processing unit 54 Infrared receiving circuit 55, 56 Ultrasonic receiving circuit

Claims (1)

At least an infrared transmission circuit including an infrared generation element, an ultrasonic transmission circuit including an ultrasonic generation element, and a means for detecting acceleration, and repeating infrared signals and ultrasonic signals from the infrared transmission circuit and the ultrasonic transmission circuit An electronic pen comprising: a signal transmission unit for transmitting; a writing unit having a function capable of directly leaving a locus on a recording medium; and a pen switch for determining whether or not the writing unit is in a writing state; At least one infrared receiving unit having a function of receiving the infrared signal, two or more ultrasonic receiving units having a function of receiving the ultrasonic signal, the infrared signal and the ultrasonic signal. A signal receiving unit having a receiving circuit for detecting reception, and the electronic pen and the ultrasonic receiving unit from the arrival time difference between the infrared signal and the ultrasonic signal Handwritten handwriting comprising: a coordinate calculation unit that calculates a distance and calculates the position coordinate data of the electronic pen using the distance; and a conversion processing unit that has a function of converting the position coordinate data of the electronic pen into handwriting data In the input system, when the acceleration applied to the electronic pen increases , the signal transmission unit shortens the repeated transmission interval of the infrared signal and the ultrasonic signal, and when the acceleration decreases, the infrared signal And a handwriting handwriting input system, characterized in that the interval between repeated transmissions of the ultrasonic signals is lengthened .

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