WO2012024899A1 - 一种平板结构的超声波手写板 - Google Patents

一种平板结构的超声波手写板 Download PDF

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Publication number
WO2012024899A1
WO2012024899A1 PCT/CN2011/001432 CN2011001432W WO2012024899A1 WO 2012024899 A1 WO2012024899 A1 WO 2012024899A1 CN 2011001432 W CN2011001432 W CN 2011001432W WO 2012024899 A1 WO2012024899 A1 WO 2012024899A1
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WO
WIPO (PCT)
Prior art keywords
ultrasonic
pen
signal
handwriting
tablet
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Application number
PCT/CN2011/001432
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English (en)
French (fr)
Inventor
刘中华
Original Assignee
北京爱易玛克科技有限公司
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Publication of WO2012024899A1 publication Critical patent/WO2012024899A1/zh

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Classifications

    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/041—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means
    • G06F3/043—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves
    • G06F3/0433—Digitisers, e.g. for touch screens or touch pads, characterised by the transducing means using propagating acoustic waves in which the acoustic waves are either generated by a movable member and propagated within a surface layer or propagated within a surface layer and captured by a movable member
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01B—MEASURING LENGTH, THICKNESS OR SIMILAR LINEAR DIMENSIONS; MEASURING ANGLES; MEASURING AREAS; MEASURING IRREGULARITIES OF SURFACES OR CONTOURS
    • G01B17/00—Measuring arrangements characterised by the use of infrasonic, sonic or ultrasonic vibrations
    • G—PHYSICS
    • G06—COMPUTING; CALCULATING OR COUNTING
    • G06F—ELECTRIC DIGITAL DATA PROCESSING
    • G06F3/00—Input arrangements for transferring data to be processed into a form capable of being handled by the computer; Output arrangements for transferring data from processing unit to output unit, e.g. interface arrangements
    • G06F3/01—Input arrangements or combined input and output arrangements for interaction between user and computer
    • G06F3/03—Arrangements for converting the position or the displacement of a member into a coded form
    • G06F3/033—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor
    • G06F3/0354—Pointing devices displaced or positioned by the user, e.g. mice, trackballs, pens or joysticks; Accessories therefor with detection of 2D relative movements between the device, or an operating part thereof, and a plane or surface, e.g. 2D mice, trackballs, pens or pucks
    • G06F3/03545—Pens or stylus

Definitions

  • This invention relates to a handwriting input device for a computer, and belongs to the field of acoustic signal generation and acquisition technology, and more particularly to the application of acoustic technology in the field of computer data input technology.
  • the existing handwriting input technologies mainly include resistive film technology, capacitive sensing technology, electromagnetic induction technology, infrared optical technology, electromagnetic induction technology, space ultrasonic technology, and surface acoustic wave technology.
  • resistive film technology capacitive sensing technology
  • electromagnetic induction technology infrared optical technology
  • electromagnetic induction technology space ultrasonic technology
  • surface acoustic wave technology The use of these technologies constitutes several basic tablet technology solutions that satisfy many applications. But these technologies also have their own shortcomings, thus limiting their application in certain areas. For example, in the application of full-size large-size handwriting tablet applications, the application of these technologies is greatly limited.
  • the resistive film technology and the induction capacitor technology have poor light transmittance, and when applied
  • the palm or wrist can not be pressed on the screen and it is easy to fatigue, and the resistive film technology has the disadvantage of being scratch-resistant;
  • the problems of infrared optical technology, surface acoustic wave technology and spatial ultrasonic technology are: It is located on the upper surface of the tablet, so it is used on the display. There are sensor parts and even the frame needs to protrude on the surface of the display screen. It is impossible to achieve full flatness; and the surface acoustic wave technology and the ultrasonic reflection stripe are easily affected by dirt and cannot be used. problem.
  • the most suitable technology for handwriting tablets is electromagnetic induction technology, such as the Chinese patents number ZL02105382. 0 and ZL03238835.
  • An object of the present invention is to provide a tablet having a full flat writing surface and a structure for manufacturing a writing substrate using a transparent hard material for constructing a tablet having a flat display surface.
  • the ultrasonic handwriting board of the invention comprises a handwritten ultrasonic pen equipped with an ultrasonic transmitter, and the ultrasonic receiver installed at different positions comprises the same ultrasonic signal receiving and amplifying processing circuit as the ultrasonic receiver, respectively, through the input and output ports Connected to the amplification processing circuit and the computer system, including data An ultrasonic data calculation processing unit of the specification processor, a signal transmission channel coupled to the ultrasonic transmitter and the data calculation processing unit, for calibrating an ultrasonic pulse emission time, and a ultrasonic transmission pen capable of detecting the ultrasonic wave Pen writing pressure piezoelectric signal detecting element.
  • the ultrasonic receivers are respectively mounted on the surface of the edge of the isotropic hard bottom plate; the ultrasonic transmitter mounted in the ultrasonic pen has a vibration output end and the ultrasonic pen The nib is mechanically coupled, and the nib of the ultrasonic pen is made of a hard elastic material.
  • the ultrasonic receiver may be mounted on the front or back side of the bottom plate or the side of the bottom plate if only from the realization of the function. However, if all the objects of the invention are to be achieved, the ultrasonic receiver can be mounted on the side or the reverse side of the handwriting base to achieve a full flat design of the writing surface of the tablet.
  • the handwriting ultrasonic pen of the present invention can have both wireless and wired configurations.
  • the ultrasonic pen and the ultrasonic data calculation processing unit are connected by a cable as a signal transmission channel for calibrating the transmission time of the ultrasonic signal; in the ultrasonic data calculation processing unit, An ultrasonic signal generator is included, coupled to an ultrasonic transmitter in the ultrasonic pen through a wire in the cable; the piezoelectric signal detecting element is also passed through a wire in the cable The ultrasonic data calculation processing units are connected.
  • the ultrasonic pen When the ultrasonic pen is a wireless pen, the ultrasonic pen further includes an ultrasonic generating circuit connected to the ultrasonic transmitter, and a power source composed of the energy storage element; the ultrasonic receiver has four, and The ultrasonic signal receiving and amplifying processing circuit corresponding to the ultrasonic signal receiving circuit also has four sets, which are all formed into four signal detecting processing channels; the signal transmission channel for calibrating the ultrasonic signal transmitting time is composed of one of the four signal detecting processes.
  • the piezoelectric signal detecting element may be a pressure detecting element capable of outputting an electrical signal having a specific function relationship with the pressure received by the tip of the ultrasonic pen, that is, a pressure/electrical signal sensor, or A pressure switch.
  • the pressure detecting element can be connected to the ultrasonic data processing unit through a cable connecting the ultrasonic pen, and the "pressure/electric signal" sensor can be conveniently used to obtain the user's writing.
  • the switch can also be installed in the ultrasonic pen for the ultrasonic transmitter and the device connected in the ultrasonic pen. On the wire in the cable.
  • this binarized pressure switch can also be connected to the control end of the circuit inside the ultrasonic pen for controlling the ultrasonic transmission.
  • the ultrasonic pen is a wireless pen
  • the data of the pressure detecting element of the electrical signal having a specific function relationship with the pressure cannot be transmitted, so a binarized pressure switch is generally used.
  • the isotropic handwriting substrate may be a transparent glass plate or a plexiglass plate made of a polymer material.
  • the ultrasonic frequency to be used is several hundred kilohertz or more, it is generally required to use piezoelectric ceramics as ultrasonic wave transmitting transducers.
  • the ultrasonic transducer is coupled with the tip of the ultrasonic pen by mechanical means.
  • an ultrasonic horn can be included in the pen tip, and the amplitude amplification end of the horn is used as the stylus. Writing end.
  • an analog/digital converter can be used to convert the analog ultrasonic signal received by the receiver into a digital signal, and then the ultrasonic data calculation processing unit can be utilized.
  • the ultrasonic data calculation processing unit further includes an A/D converter having the same number as the ultrasonic receiver and the signal amplification processing circuit thereof; the input ends of each of the A/D converters are respectively Connected to the output of each of the ultrasonic signal amplification processing circuits, the output is connected to an internal or external I/O interface of the ultrasonic data calculation processing unit through I/O.
  • the tablet of the present invention has the advantages of simple structure, wide application, low cost, high precision, long life, and maintenance-free. Especially when a transparent material is used as the handwriting backplane, the tablet of the present invention can be directly mounted on the surface of various flat panel displays, and is used as a low-cost input device for a handwriting screen or a tablet computer.
  • FIG. 1 Schematic diagram of the basic structure of the present invention
  • Figure 2 A graph of different propagation modes and phase velocities of ultrasonic waves in a rigid elastic plate
  • Figure 3 Schematic diagram of the installation of the ultrasonic receiver on the side of the handwriting base
  • Figure 4 structural block diagram of a wired ultrasonic stylus
  • Figure 5 Structural block diagram of a wireless ultrasonic stylus
  • Figure 6 Basic structure of the ultrasonic stylus
  • Figure 7 The basic structural shape of the horn in the stylus tip
  • Figure 8 A schematic view of a structure of a pressure switch composed of a stylus tip
  • Figure 9 Block diagram of the structure of a data processing unit using an A/D converter.
  • the basic structural form of the tablet of the present invention is shown in FIG.
  • the tip of the stylus 106 is in contact with the surface of the handwriting substrate 101, and the ultrasonic waves emitted by the pen tip excite the handwriting substrate to generate ultrasonic vibrations 107 propagating in various directions, reaching the ultrasonic receivers 102, 103 and 104.
  • the role of the controller 108 is to receive, Amplifying, processing, and analyzing the ultrasonic signal received by the ultrasonic receiver, and calculating the coordinates of the writing end of the ultrasonic stylus in a certain coordinate system by calculation, and the signal input end is connected to the ultrasonic receivers 102, 103, 104 through the wires.
  • the receiver After the receiver receives the ultrasonic signal, after the amplification, filtering, processing, and calculation by the controller, the time interval at which the ultrasonic wave is emitted from the tip of the ultrasonic pen to each receiver is obtained, and the ultrasonic wave is obtained through mathematical calculation.
  • the position coordinates of the pen tip on the handwriting base are then transmitted through the output port 110 to the computer using the tablet.
  • the structure in Figure 1 also shows two configurations using wired and wireless ultrasonic pens.
  • the stylus is connected to the controller via the cable 109, as indicated by the dashed line in the figure; if a wireless ultrasonic pen is used, an ultrasonic receiver 105 is attached to the handwriting base plate, through the wire and the controller 108. Connected, also shown in the dotted line in the figure.
  • the ultrasonic stylus 106 transmits the longitudinal ultrasonic wave vibrating and propagating in the direction of the pen tip at an angle ⁇ to the surface of the handwriting substrate 101 through its writing end 201
  • the thickness of the plate is comparable to the wavelength of the ultrasonic wave
  • the nib will stimulate the handwritten bottom plate to produce very complex vibrations.
  • the wave propagation acts in a way of reflection and refraction with the boundary, and modal transformation between the transverse wave and the longitudinal wave occurs.
  • the incident angle ⁇ is some value
  • various modes of guided wave vibrations, Lamb waves are generated in the panel.
  • the ultrasonic waves in the flat panel exhibit some characteristics that ordinary ultrasonic waves do not have.
  • the Lamb waves in the slab have symmetric and antisymmetric modes, the symmetric modes are S0, Sl, ..., and the antisymmetric modes are A0, A1, ..., see the multiple curves 301 in Fig. 3.
  • the example of Figure 3 shows the phase velocity dispersion curves of the Lamb waves in an aluminum plate.
  • a guided wave (Lamp wave) in a plate its phase velocity is the propagation velocity of the wavefront of the same frequency, which is a function of the product of plate thickness and frequency, and the formation of the mode is related to the incident angle ⁇ .
  • the incident angle ⁇ is changed at any time, that is, the posture of the pen changes as the user writes. Change, so that the process of propagation in the handwriting base 101 will change accordingly, so whether the ultrasonic wave propagates in the handwriting base plate by the fixed mode lamb wave or other stray waveform without the fixed mode, the propagation phase of the ultrasonic wave Speed is an unknown variable. Therefore, a Cartesian coordinate system ⁇ 0 ⁇ is established in the structure shown in Fig.
  • the wave velocity of the fastest ultrasonic wave in the bottom plate is v
  • the time of propagation to the four receivers is respectively Is ti, t 2 , t 3 and t 4 , Bay ij :
  • the transmission time of the ultrasonic wave and the received time ti are known, so the equation can be obtained according to Fig. 1. group:
  • equation (1) there are three unknown ultrasonic probe tip coordinates x, y and the unknown phase velocity v of the unknown mode. Therefore, solving the equations (1) can obtain the values of the above three unknowns.
  • equation (2) there are a total of seven unknowns x, y, v, ti, t 2 , t 3 , t 4 , so the solution of equation (2) can be used to obtain the values of these seven unknowns.
  • the basic structure of the present invention as shown in Fig. 1 is mainly the ultrasonic transmitting and receiving portion.
  • the basic structure is mainly the ultrasonic transmitting and receiving portion.
  • Fig. 2 also shows a mounting structure of each ultrasonic receiver 203 on the handwriting base 101.
  • the ultrasonic receiver 203 is the basic structure of one or all of the receivers of the ultrasonic receivers 102, 103, 104 or 105 of FIG. 1, that is, an ultrasonic receiver composed of a piezoelectric ceramic sheet and a metal electrode. Installed on one end surface 202 of the handwriting base 101. In this way, an ultrasonic receiver of a specific vibration mode can be used to receive the longitudinal wave having the fastest propagation speed, and the receiver can be prevented from being exposed on the surface of the handwriting substrate.
  • the signal conditioning channels constituting the controller 108 for amplifying, filtering, and the like of the signals received by the respective ultrasonic receivers are constructed, and the microcontroller (MCU) is built as a core. Threshold signal comparison, transmission time timing, coordinate value calculation and transmission to the use of the present invention through the output port A signal processing, transmission unit, and a structure of a handwritten ultrasonic pen for transmitting ultrasonic waves to a handwriting substrate are described.
  • FIG. 4 and Figure 5 show block diagrams of the implementation of wired and wireless ultrasonic pens.
  • the tip 401 of the ultrasonic pen and the ultrasonic transducer 402 are mechanically coupled to the ultrasonic transmitting transducer 402 by some connection means such as imperative bonding, bonding, welding, etc., as shown by the interlocking dotted line with an arrow in the figure. , so that the ultrasonic vibrations generated by the transducer can be transmitted to the nib with minimal loss.
  • the ultrasonic transducer is a piezoelectric transducer composed of a light transmissive piezoelectric material and a light transmissive electrode.
  • the transparent piezoelectric material may be a PVDF piezoelectric film or a lead zirconate titanate (PLZT) piezoelectric material; the transparent electrode may be a material such as IT0.
  • the pressure detecting element 403 (pressure sensing element PR in the figure) capable of detecting the tip pressure at the time of writing.
  • these components are coupled to the microcontroller system in controller 108 via connection port 404 and cable 405. Since it is a wired pen, the pressure detecting element 403 in the figure can also use an element capable of outputting an electrical signal having a specific functional relationship with the pressure applied to the tip of the ultrasonic pen, as disclosed in Chinese Patent Application No. 201010101907.
  • a "pressure/electrical signal" conversion element even a conductive rubber whose resistance varies with pressure.
  • the electric signal outputted by the pressure detecting element 403 is transmitted to the controller 108 through the wire in the cable 405, processed by the same, and encoded together with the coordinate signal obtained after the processing, and output to the computer using the present invention as a control.
  • an ultrasonic wave transmitting transducer made of a piezoelectric material such as a piezoelectric ceramic transducer is generally required.
  • an ultrasonic generating and driving circuit 501 which is generally composed of an analog or digital component system, and a built-in energy storage component are included.
  • a pressure detecting element capable of outputting an electrical signal having a specific function relationship with the pressure received by the tip of the ultrasonic pen is generally not used, and the use can only detect the pass.
  • the broken binarization pressure switch acts as a writing pressure detecting element.
  • the general mechanical implementation structure of the wireless ultrasonic stylus is shown in FIG. 6.
  • the main components are composed.
  • the function of the limiting mechanism 603 is to prevent the pen tip from crushing the pressure switch 403 when the writing pressure is too large (in the case that the switch cannot withstand a large pressure);
  • the role of the transmitter bracket 602 is to protect the transmitter, and also The transmitter matches the appropriate acoustic impedance.
  • piezoelectric ceramics can generally be used to produce ultrasonic waves in a thickness mode to emit ultrasonic waves, which has the advantages of low cost and high efficiency.
  • the ultrasound letter The number is the modulated ultrasonic signal.
  • the optional modulation method is pulse modulation (transmitting a set of ultrasonic pulses at regular intervals), amplitude modulation or frequency modulation.
  • the nib 401 is the only path through which the ultrasonic wave propagates from the emitter to the handwriting base plate.
  • the surface of the handwriting base plate is not in contact with the handwriting base plate, and the surface of the handwriting base plate cannot be scratched, and the loss is required to be small. Therefore, the elastic modulus of the material is required to be large and the hardness is moderate. Organic materials such as various polymers are manufactured.
  • the design of the horn can also be applied to the tip of the pen to amplify the small vibration of the transmitter 402 at the writing end of the pen tip.
  • the entire nib can be composed of a horn, or a horn can be included in the nib.
  • the main structure of the nib is a horn, but the writing end can be embedded with other suitable acoustic waves, and the hardness is relative to A writing head made of other materials with a lower surface of the handwriting (not shown).
  • the section coupled to the vibrating surface of the ultrasonic transmitter 402 can be tightly coupled to the surface of the emitter in a variety of ways to ensure that ultrasonic vibrations are transmitted to the nib as little as possible.
  • Figure 7 shows the basic shape of several horns.
  • the book contains four commonly used horns: a conical horn 701, a catenary horn 702, a stepped horn 703, and an exponential horn 704.
  • a conical horn 701 a conical horn 701
  • a catenary horn 702 a catenary horn 702
  • a stepped horn 703 a conical horn 701
  • the structure of the wired handwriting ultrasonic pen is simpler than the wireless handwriting ultrasonic pen, and even does not need to have other electronic components built in, the simplest structure only needs to connect the two components of the ultrasonic transmitter and the pressure detecting component to the controller through the wire, so The structure is not specifically described here, and can be designed and manufactured with reference to the structure of the wireless ultrasonic pen. If a built-in auxiliary circuit, such as a signal drive, more function switches, etc., is required, the entire space of the outer casing 601 of Fig. 6 except the pressure detecting element can be used to mount these components.
  • a static contact 801 is disposed on a structure inside the ultrasonic pen, such as an inner wall of the outer casing or a circuit board 804 (the circuit board is shown), and then mechanically connected to the pen tip.
  • a movable contact 802 is disposed on the bracket 602 on which the ultrasonic transducer is mounted, and the nib 401 and the bracket 602 are commonly connected to a fixed structure of the ultrasonic pen through an elastic member 803, such as an inner wall of the outer casing or a circuit board.
  • an elastic member 803 such as an inner wall of the outer casing or a circuit board.
  • the two contacts constitute a pressure switch, and the two contacts are respectively connected in series between the ultrasonic transmitter in the ultrasonic pen and the ultrasonic signal generator in the ultrasonic data calculation processing unit.
  • the ultrasonic transmitter obtains a driving signal to emit ultrasonic waves.
  • the handwriting base used in the present invention may be any isotropic rigid sheet of resilient material having a thickness generally between 2 and 5 mm.
  • the thickness can be selected according to actual needs, as long as the thickness is within the same order of magnitude as the wavelength of the ultrasonic wave used, and the frequency of the ultrasonic wave can be between several hundred kilohertz and several megahertz.
  • the handwriting base is required to be transparent, and a handwritten base plate can be manufactured using a transparent inorganic or high molecular organic material such as glass or plexiglass or acrylic.
  • the analog signal processing part comprises a plurality of signal amplifying circuits and filtering circuits, each of the ultrasonic receivers corresponding to a single amplification and filtering circuit;
  • the digital signal processing circuit is composed of a microcontroller system, and includes each ultrasonic wave The receiver and its amplification, filter circuit corresponding to the timer trigger circuit, and an output port for communicating with the computer using the present invention. If a wired stylus is used, it also includes ultrasonic generation, drive circuitry, and its cable interface to the stylus.
  • the analog signal processing section and the digital signal processing section may use existing mature techniques, such as those disclosed in Chinese Patent No. 98242237. 7, 98242235. 0, 98101663. 4, 00133388. 7, 00124896.
  • the timer trigger circuit can be implemented using a comparator that controls the turn-on and turn-off of the timer by comparing the level output by each analog signal processing channel with a set threshold level.
  • the components of the analog channel can be selected with components whose passband is adapted to the ultrasonic wave emitted by the ultrasonic pen; and the digital processing part uses a single-chip microcomputer with good performance and a digital circuit matched with speed. Just fine.
  • the timer trigger circuit can also be implemented by an A/D converter and by numerical processing software, as shown in Fig. 9.
  • Figure 9 shows the internal structure of the controller 108 when a wired ultrasonic pen is used.
  • the core of the microcontroller system 901 is composed of a controller, an arithmetic unit, a memory and a timer, a timer B and a timer C, through an I/O port and three A/D converters 902,
  • the data outputs of 903 and 904 are connected, and the analog inputs of the A/D converter are respectively output terminals of analog signal processing channels 905, 906 and 907 connected to three ultrasonic receivers 102, 103 and 104, respectively. connection.
  • the ultrasonic generator After the ultrasonic generator outputs the ultrasonic signal, three timers A, timer B, and meter C corresponding to the respective analog circuits in the microcontroller system start counting; meanwhile, the microcontroller 901 starts receiving from The data output by each A/D converter.
  • the microcontroller uses software to analyze the received data, confirming the waveform of the received signal (such as the waveform of a specific frequency range emitted by the ultrasonic pen) and feature points (such as the maximum value, When the zero point or the specific phase point is the set data, the timer A, the timer B, and the timer C inside the control microcontroller system are stopped, so that the time-correlation of the three sets of ultrasonic waves in the handwriting backplane is obtained. Time value. The time error known from these time values, for example: If the characteristic waveform is captured and the time of arrival of the feature point is confirmed, the propagation time of the fastest ultrasonic wave in the bottom plate is calculated.
  • the waveform of the received signal such as the waveform of a specific frequency range emitted by the ultrasonic pen
  • feature points such as the maximum value
  • the timer is still counting, so when calculating the time, it is necessary to reduce the time counted by the timer, and other hysteresis such as the transducer.
  • Ultrasonic waves are removed in the time required for the ultrasonic pen to propagate in the tip of the pen, and the actual time of the ultrasonic wave propagating in the plate is obtained, which is brought into the equation (1) to solve, and the position coordinates of the tip of the ultrasonic pen on the handwriting base plate can be obtained. .
  • an ultrasonic receiver and a corresponding analog signal processing circuit and an A/D converter are added to the controller 108, and when the microcontroller system confirms that the signal received by a certain path is as described above, When the characteristic waveform and the feature point are started, the timer corresponding to the path is started to start timing. At this time, the ultrasonic connection of this road Description The book receiver actually acts as a time calibration channel. When the second road receives the characteristic waveform and the feature point, the first timer is turned off and the timer corresponding to the road is started to start timing, so that three time differences of four ultrasonic signals to each receiver can be obtained.
  • the actual time difference of the ultrasonic wave propagating in the plate is obtained, and is brought into the equation group (2) for solution, and the position coordinates of the tip of the ultrasonic pen on the handwriting base plate can be obtained.
  • a microcontroller can be used, and a high-performance single-chip microcomputer can be used, such as a 16-bit or 32-bit single-chip microcomputer, an FPGA, a CPLD, and the like having a clock frequency of up to several tens of megabytes or even hundreds of megabytes, and even a DSP or the like can be used.
  • Data processor can be used, and a processor for analyzing the signals output from the respective A/D converters.
  • the same number of A/D converters as the ultrasonic receiver and the signal amplification processing circuit thereof are included; the input ends of each A/D converter are respectively The output ends of the respective ultrasonic signal amplification processing circuits are connected, and the output terminals are connected to the internal or external I/O interfaces of the ultrasonic data calculation processing unit through I/O.
  • the above embodiments give a general structural solution in which the present invention can be implemented, but the embodiments in which the present invention can be applied are not limited to the specific structures given in the embodiments.
  • the specific structure of other parts of the handwritten ultrasonic pen, the modulation form of the transmitted ultrasonic signal, the addition of other function keys on the ultrasonic pen, or even the setting of another wireless data transmission channel using an electrical signal component having a specific function relationship with the pressure.
  • a binarized pressure switch to achieve detection of the amount of writing pressure, as well as the specific configuration of the type of ultrasonic receiver, the mode of vibration, the mounting position on the handwriting base, etc., there are many options. Therefore, on the basis of the basic structural solutions of the present invention, the technical solutions of the improvements, substitutions, omissions, and transplantation of the present invention are all within the scope of the present invention.

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Description

一种平板结构的超声波手写板 技术领域 - 本发明涉及一种用于计算机的手写输入装置， 属于声学信号发生和采集技术领域， 尤其是在声学技术在计算机数据输入技术领域的应用。
技术背晕
现有的手写输入技术， 主要有电阻膜技术、 电容感应技术、 电磁感应技术、 红外光 学技术、 电磁感应技术、 空间超声波技术、 表面声波技术。使用这些技术构成了若干种 基本的手写板技术方案， 满足了很多说应用。但是这些技术也都有各自的缺点， 因此限制 了他们在某些领域的应用。例如在全平的大尺寸的手写平板电脑应用领域，这些技术的 应用都受到了很大的限制。其中， 电阻膜技术、 感应电容技术存在透光性差、在应用时
书
手掌或手腕不能压在屏幕上而容易疲劳的缺点， 而且电阻膜技术还有不耐擦刮的缺点； 红外光学技术、表面声波技术、空间超声技术存在的问题是： 因为检测传感部件都要位 于手写板的上表面，所以用在显示器上，有传感器件甚至边框需要突出在显示屏幕表面 缺点， 不能实现全平； 并且表面声波技术， 还有超声波反射条纹容易被污物影响而不能 使用的问题。 目前最适合于手写平板电脑的技术是电磁感应技术， 如号码为 ZL02105382. 0和 ZL03238835. 7的中国专利以及类似的其他专利， 公开了一类在 LCD显 示屏幕的前面或者后面设置电磁感应层的技术方案，可以用于手写平板电脑。但这类技 术或者因为构造复杂、生产成本高而难以普及， 或者存在透明电极透光性差的问题， 所 以也难以满足平板电脑上应用要求。
申请号为 98101325. 2的中国专利申请中公开了一种利用显示器的硬质表面传播的 超声波来实现手写输入的技术方案，给出了一种将超声波接收器安装在硬质板或显示器 的硬质表面的背面的基本结构方案，理论上可以实现全平的书写界面。但是这个方案还 不是完整的技术方案。首先， 这个方案的基础是假设超声波在有限厚度的、各向同性的 硬质板中传播的速度是一定的， 没有考虑到其传播模式的复杂性； 其次， 这个技术方案 公开得不够充分， 一些必要的技术细节没有被公开， 因为也无法实用。
发明内容
本发明的目的， 就是针对现有技术的缺点， 公开了一种书写表面全平的手写板， 并 可使用透明硬质材质制造书写底板的结构， 用于构建显示表面全平的平板电脑。
本发明的超声波手写板，包含有一支安装有超声波发射器的手写超声笔，安装在不 同位置的超声波接收器， 包含有与超声波接收器的数量相同超声信号接收放大处理电 路，分别通过输入输出端口与所述放大处理电路和计算机系统相连接的、包含有数据处 说 明 书 理器的超声波数据计算处理单元，一条耦合连接所述超声波发射器和所述数据计算处理 单元、用于标定超声波脉冲发射时间的信号传输通道， 以及一个能够通过超声笔的笔尖 检测所述超声笔书写压力的压电信号检测元件。在本发明中，所述超声波接收器至少有 三只，分别安装在各向同性的硬质底板边缘的表面上；所述安装在超声笔内的超声波发 射器，其振动输出端与所述超声笔的笔尖机械耦合连接，所述超声笔的笔尖由硬质弹性 材料制造。
在本发明中，如果仅从功能的实现来考虑，所述超声波接收器可以安装在所述底板 的正面或者反面的边缘， 也可以是底板的侧面。但如果要全部的发明目的， 则超声波接 收器可以安装在手写底板的侧面或者反面， 即可实现手写板书写表面的全平的设计。
本发明的手写超声笔可以有无线和有线两种结构形式。
当所述手写超声笔为有线笔时，超声笔与所述超声波数据计算处理单元通过电缆相 连接，作为用于标定超声波信号发射时间的信号传输通道；在所述超声波数据计算处理 单元中， 还包含有一个超声波信号发生器， 通过所述电缆线中的导线， 与所述超声笔中 的超声波发射器相耦合连接；所述压电信号检测元件，也通过所述电缆中的导线与所述 超声波数据计算处理单元相连接。
当所述超声笔为无线笔时，所述超声笔中还包含有一个与超声波发射器相连接的超 声波发生电路， 和一个由储能元件构成的电源； 所述超声波接收器有四只， 与此对应所 述超声信号接收放大处理电路也有四套，都成四条信号检测处理通道；所述标定超声波 信号发射时间的信号传输通道， 由这四条信号检测处理中的一路构成。
在本发明中，所述压电信号检测元件， 既可以是一个能输出与超声笔的笔尖所受到 的压力有特定函数关系的电信号的压力检测元件， 即压力 /电信号传感器， 也可以是一 个压力开关。
当超声笔为有线笔时，可以通过连接超声笔的电缆线将所述压力检测元件与所述超 声波数据处理单元相连接， 这时可以很方便地使用 "压力 /电信号"传感器获取使用者 书写时的压力大小，用于控制超声笔笔划粗细的显示。如果使用只有开与关两个状态的 二值化压力开关用于检测使用者出是否在书写，则该开关还可以安装在超声笔中用于中 由于连接在超声笔中的超声波发射器和所述电缆线中的导线上。当然，这个二值化的压 力开关， 也可以与超声笔内部用于控制超声波发射的电路的控制端相连接。
当超声笔为无线笔时，如果没有其他数据传输方式，那么与压力有特定函数关系的 电信号的压力检测元件的数据就无法传输， 所以一般都使用二值化的压力开关。
本发明的手写板如果用于显示器的表面构成手写显示器，则所述各向同性的手写底 板， 可以使用透明的玻璃板或由高分子材料构成的有机玻璃板。 说 明 书 在本发明中， 因为使用的超声波频率要在几百千赫以上， 因此一般需要使用压电陶 瓷作为超声波发射换能器。超声波换能器与超声笔的笔尖通过机械的方式耦合连接， 为 补偿传输损耗甚至增加笔尖的振幅，可以在笔尖内包含一个超声波变幅杆，并将变幅杆 的振幅放大端作为手写笔的书写端。
在本发明中， 由于板内的超声波的振动传播模式复杂， 所以可以使用模拟 /数字变 换器，将接收器收到的模拟超声波信号转换为数字信号， 再通过所述超声波数据计算处 理单元利用现有的数据分析、 计算、 处理方法， 对数字化的超声波接收信号进行处理， 得到超声笔所发出的超声波在所述板内的传播速度、传播到各个接收器的时间，进而得 到超声笔笔尖所在的位置数据。 因此， 在所述超声波数据计算处理单元中， 还包含有与 超声波接收器及其信号放大处理电路的数量相同的 A/D变换器；所述每个 A/D变换器的 输入端，都分别与所述各个超声信号放大处理电路的输出端相连接，输出端通过 I/O与 所述超声波数据计算处理单元的内部或外部 I/O接口相连接。
发明的益处
通过对本发明的技术方案的描述，可以看到本发明的手写板具有结构简单、用途广 泛、成本低、精度高、寿命长、免维护等优点。尤其在使用透明的材料作为手写底板时， 本发明的手写板可以直接安装在各种平板显示器的表面，作为低成本的输入设备，应用 于手写屏幕或者平板电脑。 附图说明
图 1 ： 本发明的基本结构的示意图；
图 2 ： 硬质弹性板中超声波不同传播模式和相速度的曲线图；
图 3 ： 在手写底板侧面安装超声波接收器的结构示意图；
图 4 ； 有线超声手写笔的结构方框图；
图 5 ： 无线超声手写笔的结构方框图；
图 6 ： 超声手写笔的基本结构图；
图 7 ： 手写笔尖中变幅杆的基本结构形状；
图 8 : 由手写笔尖构成的压力开关的一种结构示意图；
图 9 ： 使用 A/D变换器的数据处理单元的结构方框图。
具体实施方式
下面参照附图来说明本发明的原理和具体实施方式。
图 1中给出了本发明手写板的基本结构形式。从图中可以看到，手写笔 106的笔尖 与手写底板 101的表面相接触，笔尖所发射的超声波激励手写底板，产生向各个方向传 播的超声波振动 107， 到达超声波接收器 102、 103和 104。 控制器 108的作用是接收、 放大、处理、解析超声波接收器所收到的超声波信号， 通过计算得到超声手写笔的书写 端在某个设定坐标系内坐标， 其信号输入端通过导线与超声波接收器 102、 103、 104相 连接，这些接收器接收到超声波信号以后，通过控制器的放大、滤波、处理、计算以后， 得到超声波从超声笔的笔尖发射出到各个接收器接收到的时间间隔，在通过数学计算的 得到超声笔笔尖在手写底板上的位置坐标， 然后通过输出端口 110, 传输到使用本手写 板的计算机。图 1中的结构同时给出了使用有线和无线超声笔的两种结构。如果使用有 线超声笔， 则手写笔通过电缆 109与控制器相连接， 如图中虚线所示； 如果使用无线超 声笔， 则在手写底板上加装一个超声波接收器 105, 通过导线与控制器 108相连接， 也 如图中虚线所示。 说
下面来说明图 1所示结构的物理和数学原理。
如图 2所示， 当超声手写笔 106通过其书写书端 201向手写底板 101的表面， 以角度 α发射沿笔尖方向振动和传播的纵波超声波， 当板厚 Η与超声波的波长可比拟时，笔尖 将激励手写底板产生非常复杂的振动， 因为手写底板存在上下表面，所以波的传播以反 射与折射的方式与边界发生作用，且发生横波和纵波间的模态转换。当入射角 α为某些 数值时，还会在板内产生各种模式的导波振动——兰姆波。于是， 平板中的超声波就呈 现出了普通超声波所不具有的一些特点。 最主要的特征就是导波的频散现象和多模式。 平板中的 Lamb波有对称和反对称模式， 对称模式有 S0、 Sl、 ……， 反对称模式有 A0、 A1 , ……， 参见图 3中的多条曲线 301。 图 3的示例给出的是铝板中兰姆波的相速度频 散曲线。 对于板中的导波 (兰姆波） 而言， 它的相速度是相同频率波前的传播速度， 是 板厚与频率乘积的函数，而模式的形成又与入射角 α相关。详细的理论分析可参考如下 专业著作和论文：
《超声手册》， 冯诺主编， 南京大学出版社 1999 年 10 月出版， 统一书号 ISBN 7-305-03354-5/0 · 237；
论文 《大型薄板中超声导波的产生与鉴别》， 作者冯占英、 周正干、 高翌飞， 刊登 于《无损探伤》期刊第 31卷第 5期， 2007年 10月号。
在本发明中，虽然超声笔所发射的超声波的频率是固定的，手写底板的厚度也是固 定的，但是入射角 α却是随时变化的，也就是随着使用者书写时的笔的姿势改变而改变， 这样手写底板 101中传播的过程也就随之改变，因此无论超声波在手写底板中传播的方 式是由固定模式的兰姆波，还是没有固定模式的其他杂散波形，超声波的传播的相速度 都是一个未知的变量。 因此在图 1所示的结构中建立直角坐标系 Χ0Υ， 假设超声笔尖所 在的位置 P (x, y)到各个超声波接收器 PI (xi, y！)、 P2 (x2， y2)、 P3 ( , y3)和 P4 (x4, 74 ) 的直线距离分别是 D2、 和¾, 底板中传播最快的超声波的波速为 v， 传播到 到这四只接收器的时间分别是 ti、 t2、 t3和 t4, 贝 ij : 说 明 书 当使用有线超声笔时， 因超声波的发射时间和被接收到的时间 ti (i是各个接收器 的编号， i=l，2,3) 都是已知的， 所以根据图 1可得方程组：
2 2 2 2
(xi-x) + <yi-y) = Di = (vti)
(x2-x) 2+ (y2-y) 2 = 2 = (vt2) 2 (1)
2 2 2 2
(x3-x) + (y3~y) = D3 = (vt3
方程组（1)中有三个未知数超声笔笔尖的坐标值 x、 y和未知模态的未知相速度 v， 因此求解方程组 （1) 即可得到上述三个未知数的值。
当使用无线笔时， 因超声波的发射时间未知，而被各个接收器接收到的时间的差值 Atij (i、 j分别是各个接收器的编号， i≠j; i、 j = l，2,3,4)， 则可以通过控制器 108 内的微控制器系统测量得到。假设以第 1个超声波接收器 102接收到超声波信号的时刻 为基准时间， 则根据图 1可得方程组：
(xi-χ) + (yi~y) = Di = (vti)
2 2 2
( 2- ) + (y2~y) = D2 = (vt2)
2 2 2
(x3-x + (y3-y) = D3 = (vt3)
(Xf x) 2+ (y~y) 2 = di = (vt4)
|t2-ti| = Δΐ2ι
Figure imgf000007_0001
|t4-ti| = ΔΪ41
在方程组（2)中， 共有 x、 y、 v、 ti, t2、 t3、 t4共七个未知数， 因此对方程组（2) 求解， 就可以得到这七个未知数的值。
因为超声波在板中的传播与在空气中或其他无限大的均匀介质中的传播模式有很 大的差别， 因此才有了本发明如图 1所示的基本结构，主要是超声波发射和接收部分的 基本结构。
图 2还给出了各个超声波接收器 203在手写底板 101上的一种安装结构。如图所示， 超声波接收器 203， 是图 1中超声波接收器 102、 103、 104或 105中一只或所有的接收 器的基本结构， 即由压电陶瓷片和金属电极构成的超声波接收器， 安装在手写底板 101 的一个端面 202上。这样，既可以使用特定振动模式的超声波接收器来接收传播速度最 快的纵波， 又可以避免接收器暴露在手写底板的表面。
具体实施中，其余部分的结构只剩下了构成控制器 108的、对各个超声波接收器所 接收到的信号进行放大、 滤波等处理的各个信号调理通道和由微控制器 （MCU) 为核心 构建的阈值信号比较、传输时间计时、坐标值计算并通过输出端口传输到使用本发明手 说 明 书 写板的计算机上的信号处理、传输单元， 以及用于向手写底板发射超声波的手写超声笔 的结构。
首先说明超声笔的实施结构。图 4和图 5给出了有线和无线超声笔的实施结构方框 图。两幅图中， 超声笔的笔尖 401与超声波换能器 402通过禁锢、粘接、 焊接等某种连 接方式， 与超声波发射换能器 402机械耦合连接， 如图中带箭头的联动虚线所示， 以便 换能器发生的超声振动能够以最小的损耗传递到笔尖上。
其中，超声波换能器是由可透光的压电材料和可透光的电极构成的压电换能器。透 光压电材料可为 PVDF压电薄膜、 锆钛酸镧铅（PLZT) 压电材料； 透明电极可为 IT0等 材料。
对于有线笔， 内部除了换能器 402， 还有一个能够检测到书写时笔尖压力的压力检 测元件 403 (图中压力感应元件 PR)。 这几个部件通过连接端口 404和电缆线 405与控 制器 108中的微控制器系统相连接。 因为是有线笔， 所以图中的压力检测元件 403， 还 可以使用能输出与超声笔的笔尖所受到的压力有特定函数关系的电信号的元件，如中国 专利申请 201010101907. 9中所公布的各种 "压力 /电信号"转换元件， 甚至使用电阻随 压力变化的导电橡胶。压力检测元件 403输出的电信号， 通过电缆 405中的导线， 传输 到控制器 108之中，通过其处理后与其处理后所得到的坐标信号一同编码，输出到使用 本发明的计算机中， 作为控制显示笔画粗细的一个变量。
本发明中的超声笔， 因为使用的超声波频率要在几百千赫以上， 因此一般需要使用 压电材料制作的超声波发射换能器， 如压电陶瓷换能器。
对于无线笔， 除了与超声发射换能器 402机械耦合连接的笔尖 401、 以及压力检测 元件 403以外,还包含有一般由模拟或数字元件系统构成的超声波发生和驱动电路 501、 内置储能元件（一般是电池） 502。
由于本发明的无线笔本身没有特别设计另外的信号传输通道，所以一般不使用能输 出与超声笔的笔尖所受到的压力有特定函数关系的电信号的压力检测元件，而使用只能 检测到通断的二值化压力开关作为书写压力检测元件。
无线超声手写笔的一般机械实施结构见图 6， 由笔尖 401、 超声波发射换能器 402、 压力开关 403、 外壳 601、 超声发射器支架 602、 限位机构 603、 超声波发生电路 501、 电源 502等主要部件构成。其中， 限位机构 603的作用是防止书写压力过大时， 笔尖压 坏压力开关 403 (在开关不能承受很大的压力的情况下）； 发射器支架 602的作用是保 护发射器， 同时也为发射器匹配合适的声阻抗。
由于本发明使用的超声波的频率一般要在几百 kHz以上，因此一般可用压电陶瓷来 制作以厚度模式振动来发射超声波， 具有成本低效率高的优点。并且， 这里的超声波信 号是被调制的超声波信号，可选的调制方式有脉冲调制（间隔一定时间发射一组超声波 脉冲）、 幅度调制或频率调制。
笔尖 401是超声波从发射器传播到手写底板上的唯一通路，要与手写底板相接触但 又不能划伤手写底板的表面， 且要求损耗小， 所以要求材料的弹性模量大、 硬度适中， 可用有机材料如各种聚合物等来制造。同时， 为了以较小的能量最大限度地激励手写底 板产生振动，还可以在笔尖中应用变幅杆的设计，将发射器 402的微小振动在笔尖的书 写端放大。整个笔尖可以由一根变幅杆构成， 也可以在笔尖中包含有一根变幅杆， 例如 笔尖的主体结构是一根变幅杆，但书写端可以嵌入由其它适合声波传导的、硬度相对于 手写底板表面低一些的其它材料制造的书写头 （图中未画出）。 笔尖的另一端， 即尾端
说
与超声波发射器 402的振动面相耦合连接的断面，则可利用各种方式将其与发射器的表 面紧密连接， 确保超声振动尽可能小损耗地被传送到笔尖上。
图 7给出了几种变幅杆的基本形状图。图中书包含有四种常用的变幅杆： 圆锥形变幅 杆 701、悬链形变幅杆 702、 阶梯型变幅杆 703、 指数型变幅杆 704。 相关选择设计的理 论和方法， 可参见前面给出的参考资料——《超声手册》 的相关章节。
由于有线手写超声笔的结构比无线手写超声笔更简单，甚至不需要内置其它电子元 件，最简单的结构只需要将超声波发射器、压力检测元件这两个元件通过导线与控制器 相连接， 故在此不再专门说明其结构， 可参照无线超声笔的结构设计生产。如果需要内 置辅助电路， 如信号驱动、更多的功能开关等， 则可以将图 6中外壳 601的内部除压力 检测元件之外的全部空间用于安装这些元件。
对于有线手写超声笔， 还可以简化压力检测元件的结构。如图 8所示， 在超声笔内 部的某个结构上， 如外壳内壁或某块电路板 804上（图中给出的是电路板）设置一个静 触点 801 ,再在与笔尖机械连接的、安装超声波换能器的支架 602上设置一个动触点 802， 并将笔尖 401和支架 602共同通过一个弹性元件 803连接到超声笔的某个固定结构上， 如外壳内壁或某块电路板上 804上（图中给出的是外壳内壁）。 这样这两个触点就构成 了一个压力开关，两个触点分别串联在超声笔中的超声波发射器和超声波数据计算处理 单元中超声波信号发生器之间。这样当笔尖被压下接通两个触电时，超声波发射器得到 驱动信号而发射超声波。
本发明所使用的手写底板可以是任何各向同性的硬质弹性材料板， 厚度一般在 2— 一 5毫米之间。 当然可根据实际需要来选择厚度， 只要厚度与所使用的超声波的波长在 同一个数量级之内， 即可以相比拟即可；而超声波的频率可以在几百千赫至几兆赫兹之 间。如果本发明应用于手写电脑、手写显示器等的表面， 要求手写底板透明， 这时可以 使用玻璃或者有机玻璃、 亚克力等透明的无机或高分子有机材料制造手写底板。
构成本发明的另一个部分——控制器 108， 主要由模拟信号处理电路和数字信号处 说 明 书 理电路两大部分构成。 其中模拟信号处理部分包含有若干条信号放大电路和滤波电路， 每一只超声波接收器都对应一路单独的放大和滤波电路；数字信号处理电路由微控制器 器系统构成，包含有与每一路超声波接收器及其放大、滤波电路相对应的计时器触发电 路、与使用本发明的计算机进行通信的输出端口。如果使用有线手写笔， 还包括超声波 发生、驱动电路及其与手写笔的电缆接口。在本发明中， 模拟信号处理部分和数字信号 处理部分可以使用现有的成熟技术， 如号码为 98242237. 7、 98242235. 0、 98101663. 4、 00133388. 7, 00124896. 0等的中国专利所公开的电路原理、 系统结构、 以及数据处理 的软件流程。在这种结构中， 计时器触发电路可以使用比较器来实现， 通过比较每条模 拟信号处理通道所输出的电平与设定的阈值电平相比较， 来控制计时器的开启与关闭。
上述电路和系统结构应用在本发明中，模拟通道的元器件可选用通频带与超声笔所 发射的超声波相适应的元器件；数字处理部分则使用性能较好的单片机及速度相配合的 数字电路即可。
在本发明中， 计时器触发电路还可以使用 A/D变换器并通过数值处理软件来实现， 如图 9所示的结构。图 9给出的是使用有线超声笔时控制器 108的内部结构。再图 9中， 微控制器系统 901的核心由控制器、 运算器、 存贮器和计时器 、 计时器 B和计时器 C 构成， 通过 I/O端口与三只 A/D变换器 902、 903和 904的数据输出端相连接， 而 A/D 变换器的模拟输入端， 则分别与三只超声波接收器 102、 103和 104相连接的模拟信号 处理通道 905、 906和 907的输出端相连接。 这样， 当超声波发生器输出超声波信号以 后， 微控制器系统内的三只与各路模拟电路相对应的计时器 A、 计时器 B、 计吋器 C开 始计时； 同时微控制器 901开始接收来自各个 A/D变换器所输出的数据。当有信号出现 时， 微控制器利用软件对所收到的数据进行分析， 在确认所接收的信号的波形（如超声 笔所发射的特定频率范围的波形）和特征点（如最大值、过零点或者特定相位点）是所 设定的数据时， 控制微控制器系统内部的计时器 A、 计时器 B以及计时器 C停止计时， 这样就得到了三组超声波在手写底板内传播的时间相关的时间值。再将这些时间值中可 知的时间误差， 例如： 如果采用捕获特征波形并通过确认特征点到达的时间的方式， 来 计算在手写底板传播最快的超声波在底板中的传播时间，这样很可能在所述特征点到达 之后而特征波形被确认之前， 所述的计时器仍在计时， 这样计算时间时， 就要减掉这段 计时器所多计的时间， 以及其他一些如换能器的迟滞、超声波在超声笔在笔尖中传播所 需要的时间等误差除去， 得到超声波在板中传播的实际时间， 带入方程组 （1 ) 求解， 即可得到超声笔的笔尖在手写底板上的位置坐标。
对于无线手写超声笔，控制器 108中要增加一路超声波接收器和相应的模拟信号处 理电路以及 A/D变换器，这时当微控制器系统在确认某一路所接收到的信号是如上所述 的特征波形和特征点时， 则启动与该路对应的计时器开始计时。此时， 这一路超声波接 说 明 书 收器实际上就起到了时间标定通道的作用。当第二路收到特征波形和特征点后，则关闭 第一路计时器并启动与该路对应的计时器开始计时，如此类推即可得到四路超声波信号 到达各个接收器的三个时间差，在除去与前述有线手写笔相似的吋间误差之后，得到超 声波在板中传播的实际时间差， 带入方程组 （2)进行求解， 即可得到超声笔的笔尖在 手写底板上的位置坐标。
在本发明中，对于从各个 A/D变换器输出的信号进行分析，有若干种成熟的方法可 供使用， 如专利号为 200510076769. 2的中国专利所公开的信号采集和处理、 计算的方 法， 以及其中的其他相关内容。本发明中使用微控制器， 可以使用高性能的单片机， 如 时钟频率高达数十兆甚至上百兆的 16位或 32位单片机、 FPGA、 CPLD等元器件， 甚至 可以使用 DSP等性能更强大的数据处理器。
在本发明中的超声波数据计算处理单元中，还包含有与超声波接收器及其信号放大 处理电路的数量相同的 A/D变换器；每个 A/D变换器的输入端，都分别与所述各个超声 信号放大处理电路的输出端相连接，输出端通过 I/O与所述超声波数据计算处理单元的 内部或外部 I/O接口相连接。
上述实施例给出了本发明可以实施的一般结构方案，但是实施本发明可用的实施方 案不只局限于实施例所给出的具体结构。例如手写超声笔其它部分的具体结构，所发射 的超声波信号的调制形式，在超声笔上增加其他功能键，甚至通过设置另外的无线数据 传输通道，使用与压力有特定函数关系的电信号的元件来替代二值化的压力开关以实现 对书写压力大小的检测， 以及超声波接收器的种类、振动模式、在手写底板上的安装位 置等具体结构， 都可以有很多种方案。 因此， 在本发明的基本结构方案的基础上， 对本 发明的改进、 替换、 省略、 移植等技术方案， 均属于本发明的保护范围之内。

Claims

权 利 要 求 书
1. 一种平板结构的超声波手写板，包括： 手写底板； 安装有超声波发射器的 手写超声笔， 内部还包含有能够检测书写压力的压力信号检测元件；超声 波接收器以及与其数量相同的超声信号接收放大处理电路;通过输入输出 端口与所述超声信号接收放大处理电路相连接、并且包含有数据处理器及 输出端口的超声波数据计算处理单元；耦合连接于所述手写超声笔和所述 数据计算处理单元、用于标定超声波脉冲发射时间的信号传输通道；其特 征在于，所述超声波接收器至少有三只，分别安装在各向同性的弹性手写 底板边缘的表面上；安装在所述手写超声笔内的所述超声波发射器，其振 动输出端与所述手写超声笔的笔尖耦合连接，并且所述手写超声笔的笔尖 由硬质材料制造。
2. 根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于，所述 超声波接收器安装在所述手写底板的侧面的不同位置上。
3. 根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于，所述 手写超声笔与所述超声波数据计算处理单元通过电缆相连接，作为用于标 定超声波信号发射时间的信号传输通道;在所述超声波数据计算处理单元 中， 还包含有一个超声波信号发生器， 通过所述电缆线中的导线， 与所述 超声笔中的超声波发射器相耦合连接；所述压力信号检测元件，也通过所 述电缆中的导线与所述超声波数据计算处理单元相耦合连接。
4. 根据权利要求 1或 3所述的一种平板结构的超声波手写板， 其特征在于， 所述压力信号检测元件，是一个能输出与超声笔的笔尖所受到的压力有特 定函数关系的电信号的压力检测元件。
5. 根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于，所述 超声笔中还包含有超声波发生电路、由储能元件构成的电源；所述手写底 板上安装的超声波接收器有四只，与此对应所述超声信号接收放大处理电 路也有四套，构成四条信号检测处理通道；所述标定超声波信号发射时间 的信号传输通道， 由这四条信号检测处理通道共同构成。
6.根据权利要求 1所述的平板结构的超声波手写板，其特征在于，所述手写 超声笔中还包含有超声波发生电路、 红外信号发生电路和红外发射元件、 由储能元件构成的电源；所述手写底板上安装的超声波接收器有三只， 与 权 利 要 求 书 此对应所述超声信号接收放大处理电路也有三套，构成三条信号检测处理 通道；所述手写板中还包含有红外接收元件及其配合的信号处理电路，与 所述数据处理单元相联接；所述手写底板上至少有部分面积由能透过红外 线的材料构成，所述的红外接收元件安装的位置，对应于所述手写底板上 能透过红外线的部分。
7. 根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于，所述 各向同性的手写底板，是透明的玻璃板或由高分子有机材料构成的有机玻 璃板。
8. 根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于：所述 超声波换能器是压电陶瓷。
9. 根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于：所述 超声波换能器是由可透光的压电材料和可透光的电极构成的压电换能器。
10.根据权利要求 1所述的一种平板结构的超声波手写板，其特征在于，在所 述超声笔的笔尖中， 包含有一根超声变幅杆； 所述变幅杆的振幅放大端, 是手写笔的书写端。
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