JP2008033895A - Handwriting input system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that when transmitting a signal for discrimination by changing an infrared signal in an handwriting input system conventionally consumes power by an electronic pen because a certain process for transmitting the signal for discrimination is needed in addition to a basic structure and function of the electronic pen, thereby reducing a continuous use time. <P>SOLUTION: The electronic pen in the handwriting input system is composed of the smallest number of components without an additional function. Various functions are preferably equipped on a part except for the electronic pen. This invention uses at least a part of an ultrasonic wave signal transmitted from the electronic pen and received in reception, that is the ultrasonic wave signal transmitted in order to generate one position coordinate. Thereby, the electronic pen can be identified and discriminated without increasing the power consumption of the electronic pen. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention is a handwriting handwriting input system comprising an electronic pen that emits at least an infrared signal and an ultrasonic signal, and means for receiving these and calculating the position coordinates of the electronic pen based on the arrival time difference. The present invention relates to a handwriting handwriting input system having a function of identifying or identifying an electronic pen using at least a part of an ultrasonic signal.

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, an infrared signal and an ultrasonic signal are transmitted from the electronic pen, and an infrared ultrasonic measurement unit transmits the infrared signal and the ultrasonic signal 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. 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.

  The basic configuration of the electronic pen is an infrared generation circuit that emits infrared rays using an infrared light emitting element, an ultrasonic generation circuit that oscillates ultrasonic waves using an ultrasonic generation element, a timer that measures time, a CPU that controls these, and this CPU A flash memory or RAM storing the program and its variables, a pen switch that is turned on / off in accordance with the writing state and the non-writing state, and a battery that supplies power to the entire electronic pen including these.

The inside of the electronic pen is an ultrasonic generation circuit. When the transistor is turned on, power is supplied to the coil, the voltage is boosted by the coil, and when the boosted voltage is supplied from the coil to the piezoelectric element that is an ultrasonic generation element, the piezoelectric element Vibrates and ultrasonic waves are generated and transmitted as ultrasonic signals for specifying the position coordinates. When the ultrasonic signal reaches the piezo element in the reception-side ultrasonic reception unit, the reception-side piezo element vibrates and an ultrasonic reception waveform is formed. Thereafter, the position coordinate data of the electronic pen is specified based on the arrival time of the shortest arrival wave (hereinafter referred to as the first wave) of the received ultrasonic wave.

  Next, as a method of generally identifying the electronic pen on the receiving side, each electronic pen stores a different identification signal in advance, and the receiving side also manages an identification signal for an arbitrary electronic pen in advance. When used, the electronic pen sends an identification signal at the same time as the position coordinate signal, and the receiving side is within the measurement area of one handwritten handwriting input system by collating the identification signal at the same time as detecting the position coordinate of the electronic pen. It is conceivable to identify a plurality of electronic pens.

In order to realize this, it is necessary to identify the electronic pen by using a signal transmitted from some electronic pen. For example, Patent Document 3 below discloses a method of transmitting an infrared signal by changing the pen pressure information of the electronic pen to the receiving side. It is expected that the electronic pen can be identified on the receiving side by transmitting an identification signal using a method similar to the writing pressure information. In any case, it is necessary to send some information from the electronic pen and collate on the receiving side.

JP-A-62-175821 U.S. Pat. No. 4,814,552 JP 2004-310598 A

The method of transmitting the identification signal by changing the infrared signal described above involves some processing for transmitting the identification signal in addition to the basic structure and function of the electronic pen. There are drawbacks such as an increase in size and a reduction in continuous use time. Also, if you want to increase the number of individuals that can be identified, it is necessary to add more changes to the infrared signal, so the signals changed for identification and the position coordinate signals are accurate so as not to affect the position coordinate measurement. It is required to distinguish between
The present invention has been made to solve the above problem, and can be used to identify and identify an electronic pen with less power consumption and without erroneous detection of position coordinates due to identification. The purpose is to realize a handwriting input system.

The present invention provides at least an electronic pen that transmits an infrared signal and an ultrasonic signal, a receiving unit that receives these signals, and a position coordinate of the electronic pen based on a reception arrival time difference between the infrared signal and the ultrasonic signal. A handwriting handwriting input system comprising a calculating means, wherein the handwriting handwriting has a function of identifying or identifying the electronic pen using at least a part of an ultrasonic signal transmitted from the electronic pen. An input system as a first gist, at least an infrared generation circuit including an infrared light emitting element, an ultrasonic generation circuit including an ultrasonic generation element, and a control means for controlling an infrared signal and an ultrasonic signal transmitted from these circuits And a writing part having a function capable of leaving a locus directly on the recording medium, and a switch for determining whether or not the writing part is in a writing state. A pen, and at least one or more infrared light receivers and two or more ultrasonic receivers; a difference in arrival time between the infrared signal and the ultrasonic signal to the infrared receiver or the ultrasonic receiver; Calculate the distance between the electronic pen and the ultrasonic receiver using the infrared ultrasonic measurement unit to be measured, and the arrival time difference and the sound speed obtained from the infrared ultrasonic measurement unit, and use the distance to calculate the distance A coordinate calculation unit for calculating the position coordinate data of the electronic pen, and a conversion processing unit having a function of converting the position coordinate data of the electronic pen into handwriting data, are transmitted from the electronic pen and received by the reception unit. A handwritten handwriting input system having a function of identifying or identifying the electronic pen using at least a part of the ultrasonic signal is a second gist.

Ideally, the electronic pen should have the same size and weight as the pen that is normally used in the basic operation of writing. In other words, in the handwriting handwriting input system, it is preferable that the electronic pen has no extra functions, has as few parts as possible, and has various functions in parts other than the electronic pen.
The present invention uses the ultrasonic signal transmitted from the electronic pen and received by reception, that is, the power consumption of the electronic pen by using at least a part of the ultrasonic signal transmitted to generate one position coordinate. The electronic pen can be identified or identified without increasing

By using the handwriting handwriting input system of the present invention, when a plurality of devices are used simultaneously near a test place such as an entrance examination, for example, there are a plurality of electronic pens in the measurement region of one handwriting handwriting input system. In this case, the coordinate calculation unit and / or the conversion processing unit can identify the position coordinate signal transmitted by an arbitrary electronic pen, and accurately correct the writer's character without causing interference with the position coordinate signal transmitted by another electronic pen. It is possible to realize a system that can input to
Further, by using the handwriting handwriting input system of the present invention, the coordinate calculation unit and / or the conversion processing unit can identify the ultrasonic signals of a plurality of electronic pens, so that the plurality of electronic pens are different from each other. It can be identified as a pen and recorded as handwriting data of a plurality of electronic pens.

The ultrasonic signal measured by the ultrasonic receiver is used to calculate the position coordinates, and if the arrival time is known, the ultrasonic signal is not used otherwise. In other words, the present invention using an ultrasonic signal for identification or identification of an electronic pen uses an ultrasonic signal after calculating position coordinates, so that erroneous detection of position coordinates due to identification is unlikely to occur.
Various methods can be used for identifying a specific electronic pen or identifying a plurality of electronic pens using an ultrasonic signal. The method of rectifying and smoothing the measured waveform and then identifying or distinguishing it from the shape of the envelope can make the measurement interval longer than the measured waveform as it is, and collates even if the measurement amount is small it can. In addition, the method of identifying or identifying the electronic pen from the repetition interval of the measurement waveform can be compared without storing a special calculation process only by storing the time of the repetition interval. These methods can identify or identify an electronic pen relatively easily.
In general, it is known that noise is generated in a high frequency component. By performing Fourier transform on the measurement waveform of the ultrasonic receiver, the frequency band to be collated when identifying the electronic pen can be set to a frequency band that does not contain noise, so noise and ultrasonic waves transmitted from the electronic pen It is possible to increase the identification accuracy by separating the signal.

By changing the control means for controlling the ultrasonic wave generation circuit of the electronic pen, it is possible to change the ultrasonic waveform. In other words, the electronic pen is provided with a switching function that allows the writer to change the waveform arbitrarily, and by storing the handwriting data conversion method corresponding to the measured waveform in advance on the receiving side, the writer can use one electronic pen. For example, it is possible to select a function as a writing instrument such as changing the color of handwriting data or changing the thickness of a line.

A technique for identifying or identifying a plurality of electronic pens using at least a part of the ultrasonic signal can be selected as appropriate according to the frequency band of the ultrasonic generating element used and its control method. Regarding the identification method, the level of identification accuracy can be appropriately selected according to the configuration, performance, and function of the handwriting handwriting input system, and examples include the methods shown in the following paragraphs. In addition, the electronic pen identification or identification method according to the present invention may be used individually or in combination, for example, to simultaneously identify the waveform shape and the rectified and smoothed envelope shape. Or by combining with other identification methods such as a method of separately identifying and sending identification signals from other known electronic pens to improve identification accuracy or diversify the contents that can be identified It is also possible to do.

As a first method for identifying a specific electronic pen or identifying a plurality of electronic pens as individual electronic pens, a measurement waveform of an ultrasonic signal received by a coordinate calculation unit and / or a conversion processing unit A method is conceivable in which the shape of the image is measured and collated with the shape of the identification target stored in advance on the receiving side.
Variations in circuit elements such as piezo elements and coils that are ultrasonic generation elements of electronic pens, attachment methods, and distortions generate ultrasonic signals with different waveforms for each electronic pen. It is measured as a different waveform. The electronic pen can be identified or identified from the waveform shape.

To identify and identify the electronic pen, for example, the measurement waveform of the ultrasonic signal of the electronic pen received for the first time after the power is turned on, or the measurement waveform of the ultrasonic signal of the electronic pen received first after writing May be stored in the coordinate calculation unit and / or the conversion processing unit, and then collated with the value stored in the measurement waveform of the next received ultrasonic signal.
In order to store the measurement waveform of the ultrasonic signal of the electronic pen in the coordinate calculation unit and / or the conversion processing unit, for example, a button for waveform registration is provided in the coordinate calculation unit and / or the conversion processing unit, and the button is pressed. The measurement waveform of the received ultrasonic signal may be stored.

  The part to be collated may be the entire measurement waveform of the ultrasonic signal, or an arbitrary part can be selected. For example, in order to accurately receive the first wave, signal amplification processing is performed in the ultrasonic receiving unit, and when the signals for the first several wavelengths cannot be used for identification, or when the arrival time of the first wave is detected. When other processing cannot be performed due to the calculation process of the flight time of the accompanying ultrasonic wave, waveform measurement may be started from the time when several wavelengths have elapsed from the first wave, and the result may be used for collation. The measurement is terminated at least before the next infrared ray or ultrasonic wave is transmitted from the electronic pen. For example, when the input area is approximately A4 size, the frequency of the ultrasonic wave is around 80 kHz, and the electronic pen transmits infrared rays and ultrasonic waves 100 times / second, the transmission interval is 10 milliseconds, which is the longest of ultrasonic waves. The flight time is about 1 msec, and at least a few msec can be used as the measurement period, while the ultrasonic period is about 12.5 μsec in calculation, which is enough for verification. Information can be obtained.

The size of the waveform of the ultrasonic signal changes as a whole when the battery voltage of the electronic pen decreases, or when the distance between the electronic pen and the receiving unit is short, and when the distance between the electronic pen and the receiver is small, the size is small. For this reason, the measured waveform is compared with the stored waveform after normalizing both waveforms with their maximum values so that the difference in size of the entire waveform does not become a problem. Do. The frequency of the ultrasonic wave transmitted from the electronic pen is appropriately selected according to the size and resolution of the input area from the range of about 20 kHz to 100 MHz. However, especially when measuring individual waveforms, the measurement interval is shortened. It is necessary to accurately measure the shape of the ultrasonic waveform, and it is preferable to select a frequency of about 100 kHz or less as the ultrasonic signal.

The determination of identification or identification of the electronic pen may be performed by the coordinate calculation unit, or may be performed on the conversion processing unit by transmitting the measurement value of the ultrasonic signal to an external conversion processing unit. In the former case, only the position coordinate data of the identification target electronic pen can be transmitted to the outside. In the latter case, the electronic pen is identified by the conversion processing unit, and the conversion processing unit discards the position coordinate data of the electronic pen other than the identification target. Since the calculation load is not imposed on the coordinate calculation unit, there is no problem that processing is slow or an expensive CPU has to be selected for the coordinate calculation unit.

Here, FIG. 1 is a conceptual diagram of a measurement waveform of the received ultrasonic signal.
FIG. 1 shows the measurement waveform, and x is the measurement time of the waveform of the portion used for collation. The measurement start time a and the measurement end time b may be arbitrarily set. At this time, if the period of the measurement time x is short, the amount of information to be collated is reduced, so that the identification or identification accuracy is deteriorated.

As a second method for identifying a specific electronic pen or identifying a plurality of electronic pens as individual electronic pens, an envelope is obtained by rectifying and smoothing the waveform of an ultrasonic signal. A method of measuring and collating the envelope is conceivable.
When the measurement waveform of the ultrasonic signal is rectified, it is converted into a waveform as shown in FIG. Although full-wave rectification is performed here, half-wave rectification may be performed. By smoothing this waveform, it is converted into a more linear waveform as shown in FIG.
Since this method has a slower change in shape than the first method, it is not necessary to shorten the ultrasonic measurement interval, and an ultrasonic signal can be selected up to a frequency of about 1 MHz or less. The method described in the first method can be applied to the method for storing the identification or identification target electronic pen on the receiving side and the collation method.

  As a third method for identifying a specific electronic pen or identifying a plurality of electronic pens as individual electronic pens, a method of using a measurement waveform repetition interval of an ultrasonic receiving unit is conceivable. The repetition interval is represented by a1, a2, a3, a4, a5, b1, b2, b3, c1, c2, etc., among the measured waveforms at the ultrasonic receiving unit as shown in FIG. Any predetermined interval, and one or a plurality of these intervals can be used for identification or identification. It is also possible to identify and identify different electronic pens using the average value of these intervals. Variations in circuit elements such as piezo elements and coils that are ultrasonic wave generation elements of electronic pens, attachment methods, distortions, and the like are repeated intervals such as a1, a2, and a3 that differ for each electronic pen. Therefore, the electronic pen can be identified or identified by measuring the repetition interval of the measurement waveform of the ultrasonic receiving unit.

As a method of measuring the repetitive interval, for example, a zero cross detection circuit that measures a time when the ultrasonic signal does not receive an ultrasonic wave, for example, a crossing time of 0 V, or a time from peak to peak of a measurement waveform is used. It is good to measure. FIG. 4 is a conceptual diagram in which the measured values are graphed using zero cross detection means. The horizontal axis represents the zero crossing interval, and the vertical axis represents the elapsed time of zero crossing. T in the graph represents an average from t1 to t7. That is, it is possible to collate at the time from t1 to t7, or collate with the value of T.
In the coordinate calculation unit and / or the conversion processing unit, the time of the repetition interval of the electronic pen to be identified is measured and stored in advance. The method described in the first method can be applied to the method for storing the electronic pen to be identified or identified in the coordinate calculation unit and / or the conversion processing unit and the collation method.

As a fourth method for identifying a specific electronic pen or identifying a plurality of electronic pens as individual electronic pens, at least a part of the ultrasonic signal is Fourier-transformed by the coordinate calculation unit and / or the conversion processing unit. A method using the result of conversion processing is conceivable.
The variation, attachment method, distortion, etc. of circuit elements such as piezo elements and coils, which are ultrasonic generation elements of the electronic pen, are different in frequency distribution and phase of the intensity of the ultrasonic signal for each electronic pen. Thereby, the electronic pen can be identified or identified. As a value obtained by Fourier transforming the measurement waveform of the ultrasonic signal of the electronic pen, for example, a power spectrum can be used. The power spectrum refers to a frequency distribution of signal strength obtained by squaring the absolute value of a Fourier-transformed value. FIG. 5 is a conceptual diagram in which the power spectrum obtained as a result of Fourier transform of the measurement waveform of the ultrasonic signal is graphed. The horizontal axis represents frequency, and the vertical axis represents signal strength. The intensity is a relative value indicating how much each frequency component is included. In addition to the power spectrum, information on the phase may be used, and the combination of the power spectrum and the information on the phase improves the identification accuracy. The method described in the first method can be applied to the method for storing the identification or identification target electronic pen on the receiving side and the collation method.

Further, from the power spectrum of the identification target electronic pen stored in the coordinate calculation unit and / or the conversion processing unit, at least one, preferably several, frequencies at which characteristic peaks appear are selected, It may be verified by checking whether or not the received ultrasonic signal has a peak at the same frequency. At that time, for example, it is preferable to select five frequencies from the larger value, or check from the peak size. . The Fourier transform and identification of the electronic pen may be performed by the coordinate calculation unit, or the measurement value of the ultrasonic signal may be transmitted to an external conversion processing unit and performed on the conversion processing unit.

As a fifth method for identifying a specific electronic pen or identifying a plurality of electronic pens as individual electronic pens, an ultrasonic signal changed by a control means for controlling the ultrasonic signal of the electronic pen is used. A method of identifying or identifying the electronic pen by recognizing it by the coordinate calculation unit and / or the conversion processing unit is conceivable. To change the waveform of the ultrasonic signal, for example, a switch for connecting or disconnecting the coil in the ultrasonic wave generation circuit of the electronic pen is connected to the piezoelectric element, and the voltage boosted by the coil is supplied to the piezoelectric element. After at least the first wave is generated, the switch is disconnected or connected.
For example, the reception side recognizes an area where the amplitude of the waveform is larger than or relatively larger than a predetermined threshold value as an on state and other areas as an off state. As a result, the information for identifying the electronic pen is converted into a binary number, and the binary information is expressed by combining the waveform of the ultrasonic signal with ON and OFF, and the receiving side recognizes the combination of ON and OFF. In addition, since a digital communication technique that decodes identification information can be adopted, the identification accuracy of each electronic pen can be remarkably improved. Further, the same effect can be obtained by combining after changing the on and / or off time into several stages.

In this method, identification information is set in advance in the electronic pen. For example, the serial number may be converted into ON and OFF lengths at the time of manufacture and stored, or the electronic pen and the receiving side may have a function for setting an arbitrary number to the electronic pen through mutual digital communication. Alternatively, the electronic pen may be provided with a switch or dial so that it can be selected from several combinations. On the other hand, in order to store information for identifying an electronic pen to be identified on the receiving side, the information described in the first method can be applied, and when the receiving side can set a number on the electronic pen, That number may be used, and when a switch or dial is provided on the electronic pen, a similar switch or dial may be provided on the receiving side.

In the following embodiments, the electronic pen A transmits an ultrasonic signal having the waveform shown in FIG. 6A, and the waveform shown in FIG. 6B is measured by the ultrasonic receiver. Similarly, the electronic pen B transmits an ultrasonic signal having the waveform shown in FIG. 7A, the waveform shown in FIG. 7B is measured by the ultrasonic receiver, and the electronic pen C is shown in FIG. 8A. 8 is transmitted, and the waveform shown in FIG. 8B is measured by the ultrasonic receiver.
The ultrasonic generation circuit of an electronic pen is configured to transmit an ultrasonic signal at 80 kHz. However, individual differences such as the piezoelectric film that is an ultrasonic generation element and the coil of the ultrasonic generation circuit, and how to assemble the piezoelectric film , Each electronic pen transmits a slightly different ultrasonic signal.

(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.
This will be described with reference to the drawings. FIG. 9 is a perspective view showing a handwritten handwriting input system including the electronic pen 1 and the receiver 2 of the present invention. FIG. 10 is a block diagram of the inside of the electronic pen 1.
The electronic pen 1 is provided with a switch 5 that is turned on / off in accordance with a writing state and a non-writing state when the pen tip writing unit 3 draws a character or a figure while contacting the recording medium 4. . When the switch 5 is turned on, power is supplied to the control means 8 that controls the infrared generation circuit 9 and the ultrasonic generation circuit 10 in the electronic pen, and an infrared signal and an ultrasonic signal are transmitted. The transmitted infrared signal and ultrasonic signal are received by the receiver 2 and the position of the electronic pen 1 is measured using the arrival time difference.
The receiver 2 has a power button 6 and a waveform registration button 7 mounted thereon, and the internal configuration of the receiver 2 has one or more infrared light receivers and two or more ultrasonic receivers, Using an infrared ultrasonic measurement unit that measures the arrival time difference between the infrared signal and the ultrasonic signal to the infrared light receiving unit or the ultrasonic reception unit, and using the arrival time difference and the sound speed obtained from the infrared ultrasonic measurement unit A distance between the electronic pen and the ultrasonic wave reception unit is calculated, a coordinate calculation unit that calculates the position coordinate data of the electronic pen using the distance, and the position coordinate data of the electronic pen is converted into handwriting data And a conversion processing unit having the function of However, the conversion processing unit having a function of converting the position coordinate data of the electronic pen into handwriting data may be a component part of the receiver or may be separately provided in a host computer.

Here, the infrared generation circuit 9 of the electronic pen 1 includes a transistor, a resistor, and an infrared LED (not shown). When transmitting an infrared ray, when a signal transmission command is received from the control means 8, it is amplified via a transistor inside the infrared generation circuit 9, and the infrared ray that drives the infrared LED is transmitted. It is also possible to use FETs instead of transistors.
Further, the ultrasonic wave generation circuit 10 of the electronic pen 1 shown in FIG. 11 includes a coil 12, a boosting transistor 13, a diode 14, resistors 12, 15, and 16 and a piezoelectric element 11 that is an ultrasonic wave generation element. When a signal transmission command is received from the control means 4, two steps are performed to generate an ultrasonic wave. The first step is a step of turning on the boosting transistor 13 in the ultrasonic generation circuit 10 and boosting the coil 12. In the second step, the boosting transistor 13 in the ultrasonic wave generation circuit 10 of the first step is turned off to generate a counter electromotive force in the coil 12, and the counter electromotive force causes the coil 12 and the piezoelectric element 11 to This is a step of causing self-oscillation and transmitting an ultrasonic signal from the piezo element 11. The above two steps are performed to transmit ultrasonic waves.

A block diagram 12 inside the receiver 2 will be described.
The receiver 2 includes a coordinate calculation unit 101 including a CPU 102, a timer 103, a flash memory 104, and a RAM 105, and an infrared ultrasonic wave including an infrared reception unit 109, an ultrasonic reception unit 110, an ultrasonic reception unit 111, an ADC 106, an ADC 107, and an ADC 108. A conversion processing unit 112 including a measurement unit 116, a CPU 113, and a RAM 114 is mounted.
The receiver 2 samples 10 measurement waveforms received at the beginning of the period during which the waveform registration button 7 is being pressed at a rate of 100 Msamples / second for about 250 μs from the beginning. Next, the waveform obtained by averaging the ten sampled measurement waveforms is assumed to be that of the electronic pen to be identified, and stored in the flash memory 104 of the receiver 2. At this time, since the maximum voltage changes depending on the distance between the electronic pen and the receiver 2, it is normalized and stored with the maximum voltage of the measurement waveform. When the variation of the ten measurement waveforms is large, the writing is performed again. At this time, an error lamp or the like may be turned on.

Next, the operation of the receiver 2 during writing will be described. The infrared receiving unit 109 receives infrared rays and outputs them to the ADC 106. In addition, the ultrasonic receiving unit 110 receives ultrasonic waves and outputs them to the ADC 107. Similarly, the ultrasonic receiving unit 111 receives ultrasonic waves and outputs them to the ADC 108. The CPU 102 measures the infrared signal from the electronic pen 1 by the ADC 106 via the infrared receiver 109. When the CPU 102 receives a signal of a specific threshold value or more, the CPU 102 reads the current time from the timer 103 and uses this time as the arrival of the infrared light. The time is stored in the RAM 105, and then the ultrasonic signal from the electronic pen is measured by the ADCs 107 and 108 via the two ultrasonic receivers 110 and 111, and a signal equal to or greater than a specific threshold value is obtained. Is received from the timer 103, and this time is stored in the RAM 105 as the arrival time of the ultrasonic wave. Thereby, the CPU 102 measures the arrival time difference between the arrival times of the ultrasonic waves at the two ultrasonic reception units 110 and 111 stored in the RAM 105 and the arrival time of the infrared rays at the infrared light receiving unit 109. Then, the position coordinate of the electronic pen 1 is calculated based on the difference between the two arrival times and the distance between the ultrasonic receiving units 110 and 111.
Further, the CPU 102 samples the measurement waveform at 1 Msample / second for about 250 μsec from the beginning of the measurement waveform after the arrival of the ultrasonic wave of the ultrasonic reception unit 110, and stores it in the RAM 105. At this time, the measured waveform is normalized and stored with the maximum voltage. Next, after aligning the position of the maximum amplitude of this normalized measurement waveform with the measurement waveform stored in the flash memory 104 of the receiver, if the difference between the two is calculated and matched within a predetermined error, The ultrasonic signal is regarded as an effective signal as an ultrasonic signal transmitted from the pen to be identified, and if it does not match, the ultrasonic signal is excluded as not an ultrasonic signal transmitted from the pen to be identified. .

Using the above configuration, the following test was performed. The electronic pen A was stored in the receiver 2 in advance. Next, continuous writing was performed using the electronic pen A. During the writing of the electronic pen A, the electronic pen B was simultaneously written at a place about 10 cm away, and an ultrasonic signal was transmitted from both electronic pens. As a result, the receiver was able to identify the ultrasonic signal transmitted from the electronic pen A, and could record the handwriting drawn only by the electronic pen A without causing interference.

(Example 2)
The handwriting handwriting input system, the electronic pen 1, and the receiver 2 are the same as those in the first embodiment.
The receiver 2 stores the electronic pen A, the electronic pen B, and the electronic pen C. As a storing method, 10 measurement waveforms received at the beginning of a period in which the waveform registration button 7 is being pressed are sampled at 100 Msample / second only for about 200 μsec after 31.25 μsec from the beginning. Next, a waveform obtained by averaging ten sampled measurement waveforms is assumed to be that of an electronic pen to be identified, and stored in the flash memory 104 of the receiver 2. At this time, the measurement waveform is normalized and stored with the maximum voltage.
Next, continuous writing was performed using the electronic pen A. During the writing of the electronic pen A, the electronic pen B and the electronic pen C were simultaneously written at a distance of about 10 cm, and ultrasonic signals were transmitted from these electronic pens. The CPU 102 of the receiver 2 samples the measurement waveform at a rate of 100 Msample / second for about 200 μsec after 31.25 μsec from the beginning of the measurement waveform after the arrival of the ultrasonic wave from the ultrasonic receiver 110. And stored in the RAM 105. At this time, the measured waveform is normalized and stored with the maximum voltage. Next, after aligning the position of the maximum amplitude of this normalized measurement waveform with the measurement waveform stored in the flash memory 104 of the receiver, if the difference between the two is calculated and matched within a predetermined error, The ultrasonic signal is identified as an ultrasonic signal transmitted from each electronic pen, and is used as position coordinate data corresponding to each electronic pen.
As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen A, the electronic pen B, and the electronic pen C, and each drawn by the electronic pen A, the electronic pen B, and the electronic pen C. I was able to record the handwriting.

(Example 3)
The handwriting handwriting input system and the electronic pen 1 are the same as those in the first embodiment.
As shown in FIG. 13, the receiver 2 includes a coordinate calculation unit 201 including a CPU 202, a timer 203, a flash memory 204, a RAM 205, and a rectifying / smoothing circuit 215, an infrared reception unit 209, an ultrasonic reception unit 210, and an ultrasonic reception unit. 211, an infrared ultrasonic measurement unit 216 including ADC 206, ADC 207, and ADC 208, and a conversion processing unit 212 including a CPU 213 and a RAM 214 are mounted.
The receiver 2 rectifies and smoothes the ten measured waveforms received at the beginning of the period in which the waveform registration button 7 is being pressed, using the rectifying / smoothing circuit 215. The envelope after smoothing is sampled at 100K samples / second only for about 250 μsec from the beginning. Next, the waveform obtained by averaging the ten sampled envelopes is assumed to be that of the electronic pen to be identified, and stored in the flash memory 204 of the receiver 2. At this time, since the maximum voltage changes depending on the distance between the electronic pen and the receiver 2, it is normalized and stored with the maximum voltage of the envelope. When the variation of the ten measurement waveforms is large, the writing is performed again. At this time, an error lamp or the like may be turned on. Each time the waveform registration button 7 is pressed, an ultrasonic signal is transmitted from a different electronic pen, whereby a plurality of electronic pens to be identified can be recorded.

Next, the operation of the receiver 2 during writing will be described. The infrared light receiving unit 209 receives the infrared light and outputs it to the ADC 206. Further, the ultrasonic receiving unit 210 receives the ultrasonic wave and outputs it to the ADC 207. Similarly, the ultrasonic reception unit 211 receives an ultrasonic wave and outputs it to the ADC 208. The CPU 202 measures the infrared signal from the electronic pen 1 by the ADC 206 via the infrared receiver 209. When the CPU 202 receives a signal exceeding a specific threshold value, the CPU 202 reads the current time from the timer 203 and uses this time as the arrival of the infrared light. The time is stored in the RAM 205, and then the ultrasonic signal from the electronic pen is measured by the ADCs 207 and 208 via the two ultrasonic receivers 210 and 211, and the signal is equal to or higher than a specific threshold value. Is received from the timer 203, and this time is stored in the RAM 205 as the arrival time of the ultrasonic wave. Accordingly, the CPU 202 measures the arrival time difference between the arrival times of the ultrasonic waves at the two ultrasonic reception units 210 and 211 stored in the RAM 205 and the arrival time of the infrared rays at the infrared light receiving unit 209. Then, the position coordinates of the electronic pen 1 are calculated based on the difference between the two arrival times and the distance between the ultrasonic receiving units 210 and 211.
Further, the CPU 202 uses the rectifying / smoothing circuit 215 to obtain the envelope after rectifying and smoothing the output of the ADC 207 after the ultrasonic wave from the ultrasonic receiving unit 210 arrives, and only 100 K samples from the top for about 250 μs. The envelope is sampled at / second and stored in the RAM 205. At this time, it is normalized and stored with the maximum voltage of the envelope. Next, after aligning the position of the maximum amplitude of the normalized envelope with the envelope stored in the flash memory 204 of the receiver, the difference between the two is calculated and stored in the flash memory 204 in advance. If the envelope of the electronic pen's ultrasonic signal matches within a predetermined error, the ultrasonic signal is identified as an ultrasonic signal transmitted from each electronic pen and the position corresponding to each electronic pen Use coordinate data.

Using the above configuration, the following test was performed. The electronic pen A and the electronic pen B were stored in the receiver 2 in advance. Next, continuous writing was performed using the electronic pen A. While writing with the electronic pen A, the electronic pen B was simultaneously written at a location about 10 cm away, and ultrasonic signals were transmitted from both electronic pens. As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen A and the electronic pen B, and can record the handwriting drawn by the electronic pen A and the electronic pen B. It was.

Example 4
The handwriting handwriting input system, the electronic pen 1, and the receiver 2 are the same as those in the third embodiment.
The receiver 2 stores the electronic pen A, the electronic pen B, and the electronic pen C. The storage method rectifies and smoothes the ten measured waveforms received at the beginning of the period during which the waveform registration button 7 is being pressed, using the rectifying / smoothing circuit 215. Sampling is performed at 100K samples / second only for about 200 μsec after 31.25 μsec from the top of the envelope after smoothing. Next, the waveform obtained by averaging the ten sampled envelopes is assumed to be that of the electronic pen to be identified, and stored in the flash memory 204 of the receiver 2. At this time, the measured value of the envelope is normalized and stored with the maximum voltage.

Next, continuous writing was performed using the electronic pen A. During the writing of the electronic pen A, the electronic pen B and the electronic pen C were simultaneously written at a distance of about 10 cm, and ultrasonic signals were transmitted from these electronic pens. The CPU 202 of the receiver 2 obtains the envelope after rectification and smoothing of the output of the ADC 207 using the rectification and smoothing circuit 215 after the arrival of the ultrasonic wave of the ultrasonic reception unit 210, and after 31.25 μs from the beginning The envelope is sampled at 100 Ksamples / second for about 200 μsec and stored in RAM 205. At this time, the measured value of the envelope is normalized and stored with the maximum voltage. Next, after aligning the position of the maximum amplitude of the normalized envelope with the envelope stored in the flash memory 204 of the receiver, the difference between the two is calculated and stored in the flash memory 204 in advance. If the envelope of the electronic pen's ultrasonic signal matches within a predetermined error, the ultrasonic signal is identified as an ultrasonic signal transmitted from each electronic pen and the position corresponding to each electronic pen Use coordinate data.
As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen A, the electronic pen B, and the electronic pen C, and each drawn by the electronic pen A, the electronic pen B, and the electronic pen C. I was able to record the handwriting.

(Example 5)
The handwriting handwriting input system and the electronic pen 1 are the same as those in the first embodiment.
As illustrated in FIG. 14, the receiver 2 includes a coordinate calculation unit 301 including a CPU 302, a timer 303, a flash memory 304, a RAM 305, and a zero-cross detection unit 315, an infrared reception unit 309, an ultrasonic reception unit 310, and an ultrasonic reception unit 311. , An infrared ultrasonic measurement unit 316 including ADC 306, ADC 307, and ADC 308, and a conversion processing unit 312 including a CPU 313 and a RAM 314 are mounted.
The receiver 2 measures the ten measurement waveforms received at the beginning of the period during which the waveform registration button 7 is being pressed, using the zero cross detection means 315, and samples the repetition interval from the first five locations. Next, an interval obtained by averaging the repeated intervals of the ten sampled measurement waveforms is determined for the electronic pen to be identified and stored in the flash memory 304 of the receiver 2. When the variation of the ten measurement waveforms is large, the writing is performed again. At this time, an error lamp or the like may be turned on. Each time the waveform registration button 7 is pressed, an ultrasonic signal is transmitted from a different electronic pen, whereby a plurality of electronic pens to be identified can be stored.

Next, the operation of the receiver 2 during writing will be described. The infrared light receiving unit 309 receives the infrared light and outputs it to the ADC 306. The ultrasonic receiving unit 310 receives and outputs ultrasonic waves. Similarly, the ultrasonic receiving unit 311 receives ultrasonic waves and outputs them to the ADC 308. The CPU 302 measures the infrared signal from the electronic pen 1 by the ADC 306 via the infrared receiver 309. When the CPU 302 receives a signal equal to or greater than a specific threshold value, the CPU 302 reads the current time from the timer 303 and uses this time as the arrival of the infrared light. The time is stored in the RAM 305, and then the ultrasonic signal from the electronic pen is measured by the ADCs 307 and 308 via the two ultrasonic receivers 310 and 311, and the signal exceeding a specific threshold value is measured. Is received from the timer 303, and this time is stored in the RAM 305 as the arrival time of the ultrasonic wave. Thus, the CPU 302 measures the arrival time difference between the arrival times of the ultrasonic waves at the two ultrasonic reception units 310 and 311 stored in the RAM 305 and the arrival time of the infrared rays at the infrared light receiving unit 309. Then, the position coordinate of the electronic pen 1 is calculated based on the difference between the two arrival times and the distance between the ultrasonic receiving units 310 and 311.
Further, the CPU 202 uses the zero cross detection means 315 to output the output of the ADC 207 after the arrival of the ultrasonic wave from the ultrasonic receiving unit 210, and the signal level when the ultrasonic signal reaching the ultrasonic receiving unit 310 does not receive the ultrasonic wave. The crossing time is measured, five repetition intervals are measured from the beginning, and stored in the RAM 305. If the electronic pen 1 being used matches the repetition interval of the ultrasonic signal of the electronic pen 1 stored in advance in the flash memory 304 within a predetermined error, the ultrasonic signal is transmitted from each electronic pen. It is determined that the received ultrasonic signal is a position coordinate data corresponding to each electronic pen.

Using the above configuration, the following test was performed. The receiver 2 previously stored the electronic pen A, the electronic pen B, and the electronic pen C when the power was turned on. Next, continuous writing was performed using the electronic pen A. During the writing of the electronic pen A, the electronic pen B and the electronic pen C were simultaneously written at a distance of about 10 cm, and ultrasonic signals were transmitted from these electronic pens. As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen A, the electronic pen B, and the electronic pen C, and each of the drawings drawn by the electronic pen A, the electronic pen B, and the electronic pen C. I was able to record the handwriting.

(Example 6)
The handwriting handwriting input system and the electronic pen 1 are the same as those in the first embodiment.
As shown in FIG. 15, the receiver 2 includes a coordinate calculation unit 401 and an infrared reception unit 409, an ultrasonic reception unit 410, an ultrasonic reception unit 411, an ADC 406, an ADC 407, and an ADC 408 that include a CPU 402, a timer 403, a flash memory 404, and a RAM 405. An infrared ultrasonic measurement unit 416 comprising a conversion processing unit 412 comprising a CPU 413 and a RAM 414 is mounted.
The receiver 2 performs Fourier transform on the 10 measured waveforms received at the beginning of the period during which the waveform registration button 7 is being pressed, with a portion of about 250 μs from the beginning, and calculates the frequencies of the three peaks having the large power spectrum. Sampling. Next, a value obtained by averaging the frequencies of the three peaks of the ten sampled measurement waveforms is assumed to be that of the electronic pen to be identified and stored in the flash memory 404 of the receiver 2. When the variation of the ten measurement waveforms is large, the writing is performed again. At this time, an error lamp or the like may be turned on.

Next, the operation of the receiver 2 during writing will be described. The infrared receiving unit 409 receives infrared rays and outputs them to the ADC 406. In addition, the ultrasonic reception unit 410 receives an ultrasonic wave and outputs it to the ADC 407. Similarly, the ultrasonic receiving unit 411 receives ultrasonic waves and outputs them to the ADC 408. The CPU 402 measures the infrared signal from the electronic pen 1 by the ADC 406 via the infrared receiver 409. When the CPU 402 receives a signal equal to or greater than a specific threshold value, the CPU 402 reads the current time from the timer 403 and uses this time as the arrival of infrared light. The time is stored in the RAM 405, and then the ultrasonic signal from the electronic pen is measured by the ADCs 407 and 408 via the two ultrasonic receivers 410 and 411, and the signal is equal to or greater than a specific threshold value. Is received from the timer 403, and this time is stored in the RAM 405 as the arrival time of the ultrasonic wave. Thus, the CPU 402 measures the arrival time difference between the arrival times of the ultrasonic waves at the two ultrasonic reception units 410 and 411 stored in the RAM 405 and the arrival time of the infrared rays at the infrared light receiving unit 409. Then, the position coordinate of the electronic pen 1 is calculated based on the difference between the two arrival times and the distance between the ultrasonic receiving units 410 and 411.
The CPU 402 samples the measurement waveform at 1 Msample / second for about 250 μsec from the beginning of the measurement waveform after the arrival of the ultrasonic wave of the ultrasonic reception unit 410, and Fourier transforms the sampled measurement waveform. To do. Then, the power spectrum is obtained from the result of Fourier transform, three peaks are searched from the one with the largest numerical value, and the result is stored in the RAM 405. If the frequencies of the three peaks of the electronic pen 1 being used coincide with those stored in the flash memory 104 within a predetermined error, the ultrasonic signal is converted into an ultrasonic signal transmitted from the electronic pen A. If there is no coincidence, the ultrasonic signal is excluded as not being an ultrasonic signal transmitted from the electronic pen A.

Using the above configuration, the following test was performed. The electronic pen A was stored in the receiver 2 in advance. Next, continuous writing was performed using the electronic pen A. During the writing of the electronic pen A, the electronic pen B was simultaneously written at a place about 10 cm away, and ultrasonic signals were transmitted from both electronic pens. As a result, the receiver can identify the ultrasonic signal transmitted from the electronic pen A, and can record the handwriting drawn only by the electronic pen A without causing interference.

(Example 7)
This will be described with reference to the drawings. FIG. 16 is a perspective view showing a handwritten handwriting input system comprising an electronic pen 17 incorporating a stylus 20 of the present invention, a receiver 18 and a display 19. The electronic pen 17 has a switch 21 that is turned on / off in accordance with a writing state and a non-writing state when the stylus 20 draws a character or a figure while contacting the display 19. When the switch 21 is turned on, power is supplied to the control means 4 that controls the infrared generation circuit 5 and the ultrasonic generation circuit 6 in the electronic pen, and an infrared signal and an ultrasonic signal are transmitted. The transmitted infrared signal and ultrasonic signal are received by the receiver 18, the position of the electronic pen 17 is measured using the arrival time difference, and handwriting data is displayed on the display 19.
The configurations of the electronic pen 17 and the receiving unit 18 are the same as those of the electronic pen 1 and the receiving unit 2 of the fourth embodiment.
The electronic pen A and the electronic pen B are registered in the receiver 18 in advance. Next, continuous writing was performed using the electronic pen A. During the writing of the electronic pen A, the electronic pen B was simultaneously written at a place about 10 cm away, and ultrasonic signals were transmitted from both electronic pens. As a result, the receiver 18 can identify the ultrasonic signals transmitted from the electronic pen A and the electronic pen B, and displays the handwriting drawn by the electronic pen A and the electronic pen B on the display. We were able to.

(Example 8)
The handwriting handwriting input system and the electronic pen 1 are the same as those in the first embodiment.
However, the control unit 8 of the ultrasonic transmission circuit 10 of the electronic pen 1 repeats the first step and the second step after the first step and the second step for oscillating ultrasonic waves, The ultrasonic signal can be changed, and the identification information of the electronic pen is transmitted.
In this embodiment, an electronic pen D, an electronic pen E, and an electronic pen F are used. As shown in FIG. 17A, the electronic pen D controls the boosting transistor 13 in such a sequence that the period between the first process and the second process is d for the second time, as shown in FIG. A simple ultrasonic wave. Similarly, as shown in FIG. 18A, the electronic pen E controls the boosting transistor 13 in such a sequence that the period of the first process and the second process of the second time becomes e, and FIG. Transmitting ultrasonic waves like Similarly, as shown in FIG. 19A, the electronic pen F controls the boosting transistor 13 in such a sequence that the period between the first process and the second process is f for the second time. Transmitting ultrasonic waves like

An internal block diagram of the receiver 2 in this embodiment is shown in FIG.
The receiver 2 includes a coordinate calculation unit 501 including a CPU 502, a timer 503, a flash memory 504, and a RAM 505, an infrared ultrasonic wave including an infrared reception unit 509, an ultrasonic reception unit 510, an ultrasonic reception unit 511, an ADC 506, an ADC 507, and an ADC 508. A conversion processing unit 512 including a measurement unit 516, a CPU 513, and a RAM 514 is mounted.
The receiver 2 recognizes an area in which the amplitude of the ten measurement waveforms received at the beginning of the period during which the waveform registration button 7 is being pressed is greater than a predetermined threshold value as an on state, and other areas as an off state. Sampling combinations of and off. Next, a combination signal obtained by averaging ten sampled combination signals is assumed to be that of an electronic pen to be identified, and is stored in the flash memory 504 of the receiver 2. When the variation of the ten measurement waveforms is large, the writing is performed again. At this time, an error lamp or the like may be turned on. Each time the waveform registration button 7 is pressed, an ultrasonic signal is transmitted from a different electronic pen, whereby a plurality of electronic pens to be identified can be stored.

Next, the operation of the receiver 2 during writing will be described. The infrared receiving unit 509 receives infrared rays and outputs them to the ADC 506. In addition, the ultrasonic reception unit 510 receives an ultrasonic wave and outputs it to the ADC 507. Similarly, the ultrasonic reception unit 511 receives an ultrasonic wave and outputs it to the ADC 508. The CPU 502 measures the infrared signal from the electronic pen 1 by the ADC 506 via the infrared receiving unit 509. When the CPU 502 receives a signal equal to or greater than a specific threshold value, the CPU 502 reads the current time from the timer 503 and uses this time as the arrival of infrared light. The time is stored in the RAM 505, and then the ultrasonic signal from the electronic pen is measured by the ADCs 507 and 508 via the two ultrasonic receivers 510 and 511, and a signal equal to or greater than a specific threshold value is obtained. Is received from the timer 503, and this time is stored in the RAM 505 as the arrival time of the ultrasonic wave. Thus, the CPU 502 measures the arrival time difference between the arrival times of the ultrasonic waves at the two ultrasonic reception units 510 and 511 stored in the RAM 505 and the arrival time of the infrared rays at the infrared light receiving unit 509. Then, the position coordinate of the electronic pen 1 is calculated based on the difference between the two arrival times and the distance between the ultrasonic receiving units 510 and 511.
The CPU 502 recognizes the output of the ADC 507 after the arrival of the ultrasonic wave from the ultrasonic wave receiving unit 510 as an on state when the amplitude of the waveform is larger than a predetermined threshold value, and an off state when other regions are on and off. Are stored in the RAM 505. Next, if this on / off combination matches within a predetermined error with the on / off combination of the electronic pen ultrasonic signal stored in advance in the flash memory 504 of the receiver, the ultrasonic signal is It is identified as an ultrasonic signal transmitted from each electronic pen, and is used as position coordinate data corresponding to each electronic pen.

Using the above configuration, the following test was performed. The electronic pen D, the electronic pen E, and the electronic pen F were stored in the receiver 2 in advance. Next, continuous writing was performed using the electronic pen D. During the writing of the electronic pen D, the electronic pen E and the electronic pen F were simultaneously written at a distance of about 10 cm, and ultrasonic signals were transmitted from these electronic pens. As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen D and the electronic pen E, and can identify the handwriting drawn by the electronic pen D, the electronic pen E, and the electronic pen F. And was able to record.

Example 9
The description of the handwriting handwriting input system and the receiver 2 is the same as that in the eighth embodiment.
FIG. 21 shows an ultrasonic wave generation circuit of the electronic pen 1 of this embodiment. The ultrasonic generation circuit 22 includes a coil 12, a step-up transistor 13, a step-down transistor 23, a diode 14, resistors 15, 16, 24, 25, and 26, and a piezo element 11 that is an ultrasonic generation element. The difference from the eighth embodiment is that after the two steps for generating the ultrasonic wave are performed, the third step and the fourth step are performed in order to change the ultrasonic wave. The third step is a step of turning on the step-down transistor 23 in the ultrasonic generation circuit 22 and stopping the oscillation of the coil 12 and the piezo element 11 oscillating in the second step. The fourth step is a step of turning off the step-down transistor 23 in the ultrasonic generation circuit 22 to suppress the amplitude of the ultrasonic wave and to make the ultrasonic generation circuit 22 in an initial state. By changing or repeating the lengths of the third and fourth process periods, ultrasonic waves corresponding to the identification information of the electronic pen can be output. That is, the electronic pen control means 8 stores the electronic pen identification information in advance, and when the electronic pen identification information is transmitted, the ultrasonic signal is turned on / off using the third step and the fourth step. It converts into the length of off and / or on time, and transmits an ultrasonic wave. Here, the step-up transistor 23 is preferably one that contributes to the output of the ultrasonic wave, and the step-down transistor 23 is the current ultrasonic wave by the next ultrasonic wave output by the ultrasonic signal whose amplitude is suppressed. What can stop the output is good.

In this embodiment, an electronic pen G, an electronic pen H, and an electronic pen I are used. The electronic pen G controls the step-up transistor 13 and the step-down transistor 23 in a sequence as shown in FIG. 22A, and transmits an ultrasonic signal as shown in FIG. Similarly, the electronic pen H controls the step-up transistor 13 and the step-down transistor 23 in a sequence as shown in FIG. 23A, and transmits an ultrasonic signal as shown in FIG. The electronic pen I controls the step-up transistor 13 and the step-down transistor 23 in a sequence as shown in FIG. 24A, and transmits an ultrasonic signal as shown in FIG.
The receiver 2 stores the electronic pen G, the electronic pen H, and the electronic pen I. The storage method is to measure the maximum value of the amplitude of the measurement waveform at the interval of 12.5 μs from the beginning of the 10 measurement waveforms received at the beginning of the period when the waveform registration button 7 is being pressed, and calculate the average value of the maximum values. calculate. This average value is used as a threshold value and compared with the maximum amplitude value in units of 12.5 μs. If the amplitude is larger than the threshold value, the region in units of 12.5 μs is recognized as the on state, and other regions are recognized as the off state. Sampling combinations of on and off. Next, a combination signal obtained by averaging ten sampled combination signals is assumed to be that of an electronic pen to be identified, and is stored in the flash memory 504 of the receiver 2.

Next, continuous writing was performed using the electronic pen G. During the writing of the electronic pen G, the electronic pen H and the electronic pen I were simultaneously written at a distance of about 10 cm, and ultrasonic signals were transmitted from these electronic pens. The CPU 502 of the receiver 2 measures the maximum value of the amplitude of the measurement waveform at an interval of 12.5 μsec from the beginning of the measurement waveform after the arrival of the ultrasonic wave of the ultrasonic reception unit 510, and the average value of the maximum values Calculate The average value is used as a threshold value and compared with the maximum amplitude value in units of 12.5 μs. If the amplitude is larger than the threshold value, the region in units of 12.5 μs is turned on, and the other regions are turned off. Recognize and sample the combination of on and off and store in RAM 505. Next, if this on / off combination matches within a predetermined error with the on / off combination of the electronic pen ultrasonic signal stored in advance in the flash memory 504 of the receiver, the ultrasonic signal is It is identified as an ultrasonic signal transmitted from each electronic pen, and is used as position coordinate data corresponding to each electronic pen.
As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen G, the electronic pen H, and the electronic pen I, and each drawn by the electronic pen G, the electronic pen H, and the electronic pen I. I was able to record the handwriting.

(Example 10)
The handwriting handwriting input system and the electronic pen 1 are the same as those in the eighth embodiment, and the receiver 2 is the same as the first embodiment.
In this embodiment, an electronic pen D, an electronic pen E, and an electronic pen F are used.
The receiver 2 stores an electronic pen D, an electronic pen E, and an electronic pen F. As a storing method, 10 measurement waveforms received at the beginning of a period in which the waveform registration button 7 is being pressed are sampled at 100 Msample / second only for about 200 μsec after 31.25 μsec from the beginning. Next, a waveform obtained by averaging ten sampled measurement waveforms is assumed to be that of an electronic pen to be identified, and stored in the flash memory 104 of the receiver 2. At this time, the measured value of the waveform shape is normalized and stored with the maximum voltage.
Next, continuous writing was performed using the electronic pen D. During the writing of the electronic pen D, the electronic pen E and the electronic pen F were simultaneously written at a distance of about 10 cm, and ultrasonic signals were transmitted from these electronic pens. The CPU 102 of the receiver 2 samples the measurement waveform at 1 Msample / second for about 200 μsec after 31.25 μsec from the beginning of the measurement waveform after the arrival of the ultrasonic wave from the ultrasonic receiver 110. And stored in the RAM 105. At this time, the measured waveform is normalized and stored with the maximum voltage. Next, after aligning the position of the maximum amplitude of the normalized measurement waveform with the measurement waveform stored in the flash memory 104 of the receiver, the difference between the two is calculated and stored in the flash memory 104 in advance. If the measurement waveform of the ultrasonic signal of the electronic pen matches within a predetermined error, the ultrasonic signal is identified as an ultrasonic signal transmitted from each electronic pen, and the position corresponding to each electronic pen Use coordinate data.
As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen D, the electronic pen E, and the electronic pen F, and each drawn by the electronic pen D, the electronic pen E, and the electronic pen F. I was able to record the handwriting.

(Comparative example)
As a method of identifying the electronic pen, an infrared signal is transmitted from the electronic pen for identification separately from the position coordinate. In other words, infrared rays are transmitted twice to transmit one coordinate. The electronic pen in which the time from the infrared position coordinate signal to the identification signal shown in FIG. 25 is j is referred to as an electronic pen J. Similarly, the time from the infrared position coordinate signal to the identification signal shown in FIG. The electronic pen is referred to as an electronic pen K, and an electronic pen in which the time from the infrared position coordinate signal to the identification signal shown in FIG. Time intervals j, k, and m from the infrared position coordinate signal transmitted from the electronic pen J, the electronic pen K, and the electronic pen M to the identification signal are stored in advance in the flash memory. The electronic pen is identified by comparing the time from the infrared position coordinate signal transmitted from the electronic pen measured at the time of use to the identification signal with the time interval stored in the flash memory of the receiver.
As a result, the receiver can identify the ultrasonic signals transmitted from the electronic pen J, the electronic pen K, and the electronic pen M, and each drawn by the electronic pen J, the electronic pen K, and the electronic pen M. I was able to record the handwriting.

As described above, the electronic pen could be identified or identified without any problem in Examples 1 to 10 and Comparative Example. However, when the continuous use time of the electronic pen was compared, in Examples 1 to 7, continuous use was possible for about 90 hours. In Example 9, it could be used continuously for about 80 hours, and in Examples 7 and 10, it could be used continuously for about 75 hours. However, the comparative example could only be used continuously for 50 hours. In the case of the comparative example, since the infrared signal is transmitted once more for identification in order to transmit a signal for obtaining one coordinate data as compared with the first to tenth embodiments, the electronic This is because the power consumption of the pen has increased. Therefore, it was confirmed that Examples 1 to 10 are effective from the viewpoint of power consumption of the electronic pen.

Conceptual diagram of measurement waveform Conceptual diagram when smoothing after rectification Conceptual diagram of repetition interval Conceptual diagram of measuring the zero crossing of an ultrasonic signal Conceptual diagram of power spectrum Timing chart of electronic pen A Timing chart of electronic pen B Timing chart of electronic pen C Perspective view of handwriting handwriting input system consisting of electronic pen and receiver Electronic pen block diagram Internal block diagram of ultrasonic generation circuit of electronic pen Block diagram of the receiver in the first embodiment Block diagram of a receiver in the third embodiment Block diagram of a receiver in the fifth embodiment Block diagram of a receiver in the sixth embodiment The perspective view of the handwritten handwriting input system in Example 7 Timing chart of electronic pen D Timing chart of electronic pen E Timing chart of electronic pen F Block diagram of a receiver in the eighth embodiment Example 9 Ultrasonic oscillator circuit diagram Timing chart of electronic pen G Timing chart of electronic pen H Timing chart of electronic pen I Timing chart of electronic pen J Timing chart of electronic pen K Timing chart of electronic pen M

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electronic pen 2 Receiver 3 Pen tip writing part 4 Recording medium 5 Switch 6 Power button 7 Waveform registration button 8 Control means 9 Infrared generating circuit 10 Ultrasonic generating circuit 11 Piezo element 12 Coil 13 Boosting transistor 14 Diode 15 Resistance DESCRIPTION OF SYMBOLS 16 Resistance 17 Electronic pen 18 Receiver 19 Display 20 Stylus 21 Switch 22 Ultrasonic wave generation circuit 23 Step-down transistor 24 Resistance 25 Resistance 26 Resistance 101 Coordinate calculation part 102 CPU
103 Timer 104 Flash memory 105 RAM
106 ADC
107 ADC
108 ADC
109 Infrared light receiving unit 110 Ultrasonic wave receiving unit 111 Ultrasonic wave receiving unit 112 Conversion processing unit 113 CPU
114 RAM
116 Infrared ultrasonic measurement unit 201 Coordinate calculation unit 202 CPU
203 Timer 204 Flash memory 205 RAM
206 ADC
207 ADC
208 ADC
209 Infrared light receiving unit 210 Ultrasonic wave receiving unit 211 Ultrasonic wave receiving unit 212 Conversion processing unit 213 CPU
214 RAM
215 Rectifying and smoothing circuit 216 Infrared ultrasonic measurement unit 301 Coordinate calculation unit 302 CPU
303 Timer 304 Flash memory 305 RAM
306 ADC
307 ADC
308 ADC
309 Infrared light receiving unit 310 Ultrasonic receiving unit 311 Ultrasonic receiving unit 312 Conversion processing unit 313 CPU
314 RAM
315 Zero cross detection means 316 Infrared ultrasonic measurement unit 401 Coordinate calculation unit 402 CPU
403 Timer 404 Flash memory 405 RAM
406 ADC
407 ADC
408 ADC
409 Infrared light receiving unit 410 Ultrasonic wave receiving unit 411 Ultrasonic wave receiving unit 412 Conversion processing unit 413 CPU
414 RAM
416 Infrared ultrasonic measurement unit 501 Coordinate calculation unit 502 CPU
503 Timer 504 Flash memory 505 RAM
506 ADC
507 ADC
508 ADC
509 Infrared light receiving unit 510 Ultrasonic wave receiving unit 511 Ultrasonic wave receiving unit 512 Conversion processing unit 513 CPU
514 RAM
516 Infrared ultrasonic measurement unit

Claims (7)

An electronic pen that transmits at least an infrared signal and an ultrasonic signal; a receiving unit that receives these signals; and a means for calculating the position coordinates of the electronic pen based on a difference in arrival time between the infrared signal and the ultrasonic signal. A handwriting handwriting input system having a function of identifying or identifying the electronic pen using at least a part of an ultrasonic signal transmitted from the electronic pen. At least an infrared generating circuit including an infrared light emitting element, an ultrasonic generating circuit including an ultrasonic generating element, a control means for controlling infrared signals and ultrasonic signals transmitted from these circuits, and a locus directly on the recording medium An electronic pen consisting of a writing part having a function capable of leaving a mark, a switch for determining whether or not the writing part is in a writing state, at least one infrared receiving part, and two or more Obtained from an infrared ultrasonic measurement unit that has an ultrasonic reception unit, measures an arrival time difference between the infrared signal and the ultrasonic signal to the infrared light reception unit or the ultrasonic reception unit, and the infrared ultrasonic measurement unit A distance calculation unit that calculates a distance between the electronic pen and the ultrasonic wave reception unit using the arrival time difference and the sound speed, and calculates a position coordinate data of the electronic pen using the distance; A conversion processing unit having a function of converting pen position coordinate data into handwriting data, and using at least a part of the ultrasonic signal transmitted from the electronic pen and received by the receiving unit. Handwritten handwriting input system characterized by having an identification or identification function. 3. The handwriting according to claim 1, wherein the electronic pen is identified or identified using a waveform shape of at least a part of an ultrasonic signal transmitted from the electronic pen and received by the receiving unit. Handwriting input system. After rectifying and smoothing at least a part of an ultrasonic signal transmitted from the electronic pen and received by the receiving unit, the shape of the envelope is used to identify or identify the electronic pen. The handwritten handwriting input system according to claim 1 and 2. 2. The electronic pen is identified or identified by measuring a repetition interval of at least a part of an ultrasonic signal transmitted from the electronic pen and received by the receiving unit, and using the result. And 2. The handwritten handwriting input system described in 2. 3. The electronic pen is identified or identified using a result obtained by performing Fourier transform processing on at least a part of an ultrasonic signal transmitted from the electronic pen and received by the receiving unit. Handwriting handwriting input system. 7. An ultrasonic signal transmitted from the electronic pen is changed by a control unit of the electronic pen, and the electronic pen is identified or identified using the changed signal. The handwritten handwriting input system described.

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