JP2003256135A - Input indicator for coordinate input device, and coordinate input device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a constitution that can further uniformize an ultrasonic generating level in the circumferential direction of an ultrasonic generating means in an input indicator having the ultrasonic generating means formed of a cylindrical piezoelectric film regarding the input indicator for an aerial ultrasonic type coordinate input device. <P>SOLUTION: The cylindrical ultrasonic generating means 2 is constituted by linearly jointing both lateral end short sides 21, 22 of an elongate piezoelectric film 20 of parallelogrammic shape. A linear joint part 20a of the piezoelectric film 20 extends along an inclined direction to an axial direction from one axial end to the other end of the ultrasonic generating means 2, and extends over a partial circular arc range C on the circumference of the ultrasonic generating means 2. The influence of the fall of an ultrasonic generating level caused by the joint part 20a is thereby relieved being dispersed in the range C in the circumferential direction, and the ultrasonic generating level can be further uniformized in the circumferential direction. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a coordinate input device for detecting coordinates of a position arbitrarily designated by an operator and inputting the coordinates to a host device, and in particular, the coordinates of a designated position using ultrasonic waves transmitted in the air. The present invention relates to an aerial ultrasonic wave type coordinate input device for detection, and an input indicator provided with an ultrasonic wave generation means used for indicating a position where an operator inputs coordinates in this device.

[0002]

2. Description of the Related Art Conventionally, an aerial ultrasonic type coordinate input device is known, and is disclosed in, for example, Japanese Unexamined Patent Publication Nos. 8-6703 and 9-9.
No. 167046 and Japanese Patent Publication No. 7-62820. This device uses a pen-shaped or rod-shaped input indicator equipped with ultrasonic wave generating means as an input indicator for indicating the position where the operator inputs coordinates, and the ultrasonic wave generating means of this input indicator emits the sound into the air. The ultrasonic waves of the input indicator are detected based on the transmission time of the ultrasonic wave from the ultrasonic wave generation means of the input indicator to the ultrasonic sensor. Detects (calculates) the position of the generating means, that is, the coordinates of the indicated position
To do. As a result, not only two-dimensional coordinate input but also three-dimensional coordinate input is possible.

In the conventional general structure of such an aerial ultrasonic type coordinate input device, a ceramic vibrator such as PZT (zircon / lead titanate) which is a piezoelectric element is used as an ultrasonic wave generating means of the input indicator. It is used.

[0004]

However, when a ceramic vibrator such as PZT is used as the ultrasonic wave generation means of the input indicator, the vibrator itself has a relatively large Q value,
Since the allowable value for the difference between the drive frequency and the resonance frequency of the vibrator is small, the burden of management is large industrially. Also,
Since the difference in acoustic impedance between the ceramic vibrator and air is large, the ultrasonic wave emission efficiency due to vibration is low, and it is necessary to mount a diaphragm or the like. Also, when incorporating a ceramic vibrator into the input indicator as an ultrasonic wave generation means,
It is desirable that the size is as small as possible, but since the dimensions of the ceramic vibrator are defined by the resonance frequency, it is impossible to adjust the desired size and the used vibration frequency. In addition, there is a structural problem when a control switch is provided at the tip of the input indicator, so that when the ceramic oscillator is used as the ultrasonic wave generating means of the input indicator, great difficulty is involved.

On the other hand, recently, there has been proposed a structure in which a piezoelectric film made of a polymer film is used as a piezoelectric element in a cylindrical shape as an ultrasonic wave generating means of an input indicator. Specifically, as shown in FIG. 9A, the portions of the short sides 21 and 22 at both ends in the longitudinal direction of the piezoelectric film 20 having an elongated rectangular shape are bonded to each other linearly by a resin tape, a crimping member sandwiching each other, or the like. do it,
As shown in FIGS. 9B and 9C, a cylindrical shape is used as the ultrasonic wave generating means 2. Note that FIG.
In (b) and (c), reference numeral 20a is the side 2 of the piezoelectric film 20.
Since the piezoelectric film 20 is a rectangular joint between the portions 1 and 22, the piezoelectric film 20 has a rectangular shape, so that the axis of the ultrasonic generator 2 extends from one end to the other end (upper end to lower end in the figure) in the axial direction. It is a straight line that extends along the direction. This ultrasonic wave generation means 2 expands and contracts in the circumferential direction by the application of a signal to cause respiratory vibration, and as shown by the arrow in FIG. 11A, radially generates ultrasonic waves in the direction perpendicular to the outer peripheral surface. In FIG. 11A, the direction of the ultrasonic wave is indicated by the arrow direction, and the sound pressure or amplitude of the ultrasonic wave is indicated by the length of the arrow.

However, in the ultrasonic wave generating means 2 as described above, since there is no continuity as a vibrating body at the joint portion 20a of the piezoelectric film 20, the ultrasonic wave generation efficiency is lowered and the ultrasonic wave generation level is generated at the joint portion 20a. Inevitably lowers. Since the joint portion 20a is in a straight line along the axial direction of the cylinder of the ultrasonic wave generating means 2, the ultrasonic wave generation level is lowered along the axial direction by the joint portion 20a in the circumferential direction. The positions are aligned at one position. Therefore, as shown in FIG. 11A, the ultrasonic wave generation level in the circumferential direction of the ultrasonic wave generating means 2 is uniform in the portion other than the joint portion 20a when viewed in the axial direction of the ultrasonic wave generating means 2. However, only one portion of the joint 20a is significantly reduced.

Since the ultrasonic wave generation level becomes extremely uneven in the circumferential direction of the ultrasonic wave generator 2 as described above, a plurality of ultrasonic wave generators 2 depending on the orientation of the joint portion 20a of the ultrasonic wave generator 2 of the input indicator at the time of coordinate detection. There is a problem in that the ultrasonic wave detection level may be remarkably lowered by only one of the ultrasonic wave sensors, which causes a decrease in coordinate detection accuracy.

On the other hand, the ultrasonic wave generating means 2 is, for example, as shown in FIG.
As shown in (a) and (b), a part is sandwiched by a fixing member 12 such as a straight linear clip with respect to the tip portion 14 of the input indicator formed in a cylindrical shape having a smaller diameter than that. And is pressed linearly against the tip portion 14 and fixed. The fixing member 12 is attached along the axial direction of the cylinder of the ultrasonic wave generating means 2.

However, in such a structure, since the fixed portion fixed by the fixing member 12 in the ultrasonic wave generating means 2 does not have continuity as a vibrating body, a decrease in the ultrasonic wave generation level at the fixed portion is avoided. I can't. The fixed portion is in a straight line along the axial direction of the cylinder of the piezoelectric film 20. Therefore, as in the case of the joint portion 20a of the ultrasonic wave generating means 2 of FIG.
As shown in (a), in the circumferential direction of the ultrasonic wave generation means 2, the ultrasonic wave generation level is fixed by the fixing member 12 to the fixing portion 12.
There is a problem in that the portion other than a is uniform, but is significantly reduced at only one portion of the fixed portion 12a, which causes a reduction in coordinate detection accuracy.

Therefore, an object of the present invention is to provide an input indicator for an aerial ultrasonic type coordinate input device of the type described above.
To provide a structure capable of making the ultrasonic wave generation level more uniform in the circumferential direction of the ultrasonic wave generating means formed of a cylindrical piezoelectric film, and to stably perform coordinate detection using the input indicator of the structure. An object is to provide an aerial ultrasonic wave coordinate input device that can perform with high accuracy.

[0011]

In order to solve the above-mentioned problems, according to the present invention, an ultrasonic wave generating means is used to indicate a position for inputting coordinates by an aerial ultrasonic type coordinate input device. In the input indicator having the ultrasonic wave generating means, the one or more piezoelectric films are linearly joined to each other to form a cylindrical shape. The joining portion of (1) extends from one end to the other end in the axial direction of the ultrasonic wave generating means, and extends over at least a part of the arc of the circumference of the ultrasonic wave generating means.

An input indicator used to indicate a position for inputting coordinates by an aerial ultrasonic type coordinate input device, in which ultrasonic wave generating means made of a cylindrical piezoelectric film is fixed to a tip end portion. In the input indicator, the fixing portion of the ultrasonic wave generating means fixed to the distal end portion is configured to exist over at least a part of the arc of the circumference of the ultrasonic wave generating means.

Further, the above-mentioned input indicator according to the present invention,
A plurality of ultrasonic wave detecting means arranged at different positions for detecting ultrasonic waves emitted in the air from the ultrasonic wave generating means of the input indicator, and processing the ultrasonic wave detection signals of the plural ultrasonic wave detecting means. Signal processing means for generating a plurality of timing signals indicating respective arrival timings of the ultrasonic waves to the plurality of ultrasonic wave detecting means, and the plurality of timing signals from the ultrasonic wave generating means of the input indicator. Based on each of the time measuring means for measuring each of the ultrasonic wave transmission time to the ultrasonic wave detecting means and each of the ultrasonic wave transmission time measured by the time measuring means, the coordinates of the position of the ultrasonic wave generating means of the input indicator The configuration of the aerial ultrasonic type coordinate input device having a calculation means for calculating is adopted.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of an aerial ultrasonic type coordinate input device and its input indicator according to the present invention will be described below in detail with reference to the accompanying drawings.

<Description of Overall Configuration of Device> First, the overall configuration of the coordinate input device according to the embodiment will be described with reference to FIG. Figure 1
In the figure, reference numeral 1 is an input indicator for instructing the position where the user inputs coordinates in the present apparatus, and the ultrasonic wave generating means 2 is fixed to the tip of the elongated housing. The ultrasonic wave generating means 2 is configured as a cylindrical shape by joining the short side portions of both ends of a piezoelectric film having an elongated parallelogram shape in a linear shape. Reference numeral 20a is the above-mentioned linear joint portion. The details of the structure of the ultrasonic wave generating means 2 itself and the fixing structure for the tip portion of the input indicator 1 will be described later.

The ultrasonic wave generating means 2 of the input indicator 1 is connected to a vibration driving circuit 4 provided on the main body side of the coordinate input device by a cable 15 and driven by this circuit 4 to vibrate and generate ultrasonic waves. . The ultrasonic waves propagate in the air.
The frequency of the ultrasonic wave is selected to be a predetermined frequency such that the ultrasonic wave reaches a predetermined effective input area outside the audible band of several tens to hundreds of kHz. The vibration drive circuit 4 is
If there is no problem spatially or structurally, it may be provided in the housing of the input indicator 1, and a power source is also provided in the input indicator 1 so that a start signal to be described later can be transmitted between the main body of the device and the input indicator 1 by infrared light. It is also possible to make the input indicator 1 cordless by wirelessly communicating with each other.

Reference numeral 5 controls the entire apparatus and
It is an arithmetic and control circuit that calculates the coordinates of the position designated by the input indicator 1. A start signal is supplied from the arithmetic control circuit 5 to the vibration drive circuit 4 as a low-level pulse signal, amplified by the vibration drive circuit 4 with a predetermined gain, and then applied to the ultrasonic wave generation means 2 as a drive signal.
The drive signal is converted into mechanical ultrasonic vibration by the ultrasonic wave generation means 2, and the ultrasonic wave is emitted into the air.

Reference numeral 6 is a plane plate whose surface serves as a coordinate input surface, and is formed in a rectangular shape here, and ultrasonic wave detecting means composed of a piezoelectric element or the like for converting ultrasonic vibration into an electric signal at its four corners. Ultrasonic sensor (vibration sensor) 7a
7d is fixed. The flat plate 6 is
Although the front plate is arranged in front of the display surface of the display 10 arranged behind it, it may be a screen of a front projector or a whiteboard.
Further, the display surface of the display 10 may be used as the coordinate input surface without providing the flat plate 6. That is, the aerial ultrasonic wave coordinate input device does not require a specific coordinate input surface and can perform not only two-dimensional coordinate input but also three-dimensional coordinate input and can be used as a pointer.

The ultrasonic sensors 7a to 7d are the input indicators 1.
The ultrasonic wave that propagates through the air from the ultrasonic wave generating means 2 and reaches itself is detected, and the vibration of the ultrasonic wave is converted into an electric signal, that is, an ultrasonic wave detection signal. The ultrasonic detection signal is input to the detection signal processing circuit 8. Note that four ultrasonic sensors are provided here, but as described later,
It may be three or three.

The detection signal processing circuit 8 includes an ultrasonic sensor 7a.
7d to process ultrasonic wave detection signals as described later to generate four ultrasonic wave arrival timing signals (TK signals described later) indicating respective ultrasonic wave arrival timings to the ultrasonic sensors 7a to 7d, and calculate Output to the control circuit 5. The arithmetic control circuit 5 is based on each of the ultrasonic wave transmission times to the ultrasonic wave sensors 7a to 7d that are timed by the ultrasonic wave arrival timing signals, as will be described later.
The coordinates of the position of the ultrasonic wave generation means 2 are calculated.

Reference numeral 10 denotes a display arranged behind the above-mentioned flat plate 6, which is driven by a display drive circuit 11 under the control of the arithmetic and control circuit 5 and is designated by the input indicator 1, for example. Display dots, cursors, etc. at position 6. With this, handwriting input to enter characters on the screen as if drawing characters on paper,
It becomes possible to directly input on the screen the instructions that are given with the mouse.

<Explanation of Arithmetic Control Circuit 5> Next, the arithmetic control circuit 5 will be described in detail. The arithmetic control circuit 5 is at a predetermined cycle
A start signal is output to the vibration drive circuit 4 every 5 ms (for example, every 5 ms) to drive the ultrasonic wave generation means 2 of the input indicator 1, and the ultrasonic wave transmission time is started to be counted by the timer composed of the internal counter. Let

The ultrasonic waves generated from the driven ultrasonic wave generating means 2 reach the ultrasonic sensors 7a to 7d over a transmission time corresponding to the distance to the ultrasonic sensors 7a to 7d and are detected. The ultrasonic detection signal of each sensor is input to the detection signal processing circuit 8.

The detection signal processing circuit 8 is provided for each ultrasonic sensor 7
The ultrasonic detection signals from a to 7d are processed as described later to generate an ultrasonic wave arrival timing signal, and the arithmetic control circuit 5
Output to.

The arithmetic control circuit 5 inputs the ultrasonic wave arrival timing signal for each sensor, detects the ultrasonic wave transmission time to each of the ultrasonic sensors 7a to 7d based on it, and transmits the ultrasonic wave transmission time. From this, the coordinates of the position of the ultrasonic wave generating means 2 of the input indicator 1 are calculated.

Further, the arithmetic control circuit 5 drives the display drive circuit 10 based on the calculated coordinate information to control the display on the display 11, or the coordinate information to an external device (not shown) by serial or parallel communication. To output.

Next, the internal structure and operation of the arithmetic control circuit 5 will be described with reference to the block diagram of FIG.

In FIG. 2, reference numeral 31 is a microcomputer that controls the arithmetic control circuit 5 and the coordinate input apparatus as a whole and performs arithmetic operations for coordinate calculation.
It is composed of a CPU which is a main body for controlling processing, a ROM storing a control program thereof, a RAM used as a working area for calculations and the like, a non-volatile memory used for storing constants and the like, an internal counter and the like. .

Reference numeral 33 is a timer composed of a counter which counts a reference clock (not shown) and measures the ultrasonic wave transmission time from the ultrasonic wave generating means 2 of the input indicator 1 to the ultrasonic sensors 7a to 7d. . In this timer 33, the microcomputer 31 inputs the input signal to the vibration drive circuit 4
When a start signal output to drive the ultrasonic wave generating means 2 is input, counting of time starts. As a result, the start of timing by the timer 33 and the generation of ultrasonic waves by the ultrasonic wave generating means 2 are synchronized, and the ultrasonic wave transmission time until ultrasonic waves are detected by the ultrasonic sensors 7a to 7d can be measured.

The ultrasonic wave detection signals of the ultrasonic wave sensors 7a to 7d are signals having waveforms corresponding to the ultrasonic waves emitted from the ultrasonic wave generation means 2 of the input indicator 1 and propagated in the air. Then, each of the four ultrasonic wave arrival timing signals generated by the detection signal processing circuit 8 processing each of the four ultrasonic wave detection signals is paired with the ultrasonic sensors 7 a to 7 d via the signal input circuit 35. Latch circuit 34 corresponding to one
It is input to each of a to 34d.

The latch circuits 34a to 34d latch the data of the measured value of the timer 33 at the time of input of the ultrasonic wave arrival timing signal generated from the ultrasonic wave detection signal of the corresponding ultrasonic wave sensor. As a result, each ultrasonic sensor 7
The ultrasonic wave transmission time to a to 7d is timed.

When the determination circuit 36 determines that all the ultrasonic wave arrival timing signals have been input in this way, it outputs a signal to that effect to the microcomputer 31.

Microcomputer 31 receiving this
Reads the ultrasonic wave transmission time from the latch circuits 34a to 34d to the respective ultrasonic sensors, performs a later-described calculation based on the transmission time, and the ultrasonic wave generation means 2 of the input indicator 1 on the flat plate 6 Calculate the coordinates of the position. Then, by outputting the information of the calculated coordinates to the display drive circuit 11 via the I / O port 37, for example, a dot or the like is displayed on the display 10 at a position corresponding to the ultrasonic wave generating means 2 of the input indicator 1. be able to. Alternatively, the coordinate information can be output from the I / O port 37 to an external device via an interface circuit (not shown).

<Description of Detection Signal Processing Circuit 8 and Detection of Ultrasonic Wave Transmission Time> Next, the configuration and signal processing of the detection signal processing circuit 8 and the detection of the ultrasonic wave transmission time based thereon will be described with reference to FIGS. 3 to 6. . Here, the ultrasonic sensors 7a-
Two embodiments, a case of generating an ultrasonic wave arrival timing signal from an envelope of an ultrasonic wave detection signal of 7d and a case of generating an ultrasonic wave arrival timing signal from a phase, will be described. First, the former case embodiment Will be described with reference to FIGS. 3 and 4. In the following, the ultrasonic sensor 7a
The configuration and processing relating to the above will be described, but it goes without saying that the configurations and processing relating to the other ultrasonic sensors 7b, 7c, 7d are completely the same.

FIG. 3 is a timing chart of each signal related to the signal processing of the detection signal processing circuit 8, and FIG. 4 is a block diagram showing the configuration of the detection signal processing circuit 8. Figure 4
4 is provided for the ultrasonic sensors 7a to 7d, or only one set is provided and shared by each sensor in a time division manner via an analog switch or the like.

As described above, the measurement of the ultrasonic wave transmission time to the ultrasonic wave sensor 7a is started at the same time when the start signal is output to the vibration drive circuit 4. At this time, the vibration drive circuit 4
3 to the ultrasonic wave generating means 2 of the input indicator 1 in FIG.
The drive signal indicated by is applied. The ultrasonic wave generated by the ultrasonic wave generating means 2 of the input indicator 1 driven by the drive signal 41 travels in the air after a delay time (transmission time) corresponding to the distance to the ultrasonic sensor 7a. It is detected by the ultrasonic sensor 7a. The ultrasonic detection signal is indicated by reference numeral 42 in FIG. In the ultrasonic wave detection signal 42, the symbol K indicates the envelope of the ultrasonic wave detection waveform.

This ultrasonic detection signal 42 is input to the structure of the detection signal processing circuit 8 of FIG.
After being amplified to a predetermined level by, the band pass filter 511 removes an excessive frequency component and inputs it to the envelope detection circuit 52.

This circuit 52 is composed of an absolute value circuit, a low pass filter, etc., and from the ultrasonic detection signal 42,
An envelope signal 43 corresponding to the envelope K of the detected waveform is taken out. The envelope signal 43 is input to the second differentiation circuit 53 and the gate signal generation circuit 56.

The second-order differentiating circuit 53 has an envelope signal 43.
2 is differentiated to generate a second-order differential signal 45, which is output to the inflection point detection circuit 54.

The gate signal generation circuit 56 is composed of a comparator, compares the level of the envelope signal 43 with a predetermined threshold level 431, and opens at a low level for a period in which the level of the envelope signal 43 exceeds the threshold level 431. A valid gate signal 44 is generated and output to the inflection point detection circuit 54.

The inflection point detection circuit 54 is composed of a comparator, a multivibrator, and the like, and has a second-order differential signal 45.
And the gate signal 44 are compared with each other, and the zero cross point from the positive side to the negative side of the second-order differential signal 45 is detected as the first inflection point of the envelope of the ultrasonic detection signal 42 in the period in which the gate signal 44 is open, A TK signal (envelope K with a pulse width of a predetermined width that rises (becomes valid) at the time of detection
Delay time detection signal) 46 of FIG. And this T
The K signal 46 is input to the arithmetic control circuit 5 as an ultrasonic wave arrival timing signal indicating the ultrasonic wave arrival timing detected from the envelope K of the ultrasonic wave detection signal 42.

In the above-mentioned configuration of the arithmetic control circuit 5, the time TK from the rising time of the drive signal 41 of the ultrasonic wave generating means 2 to the rising time of the pulse of the TK signal 46 is the ultrasonic wave generating means of the input indicator 1. The ultrasonic wave transmission time from 2 to the ultrasonic sensor 7a is measured and detected.

In the above, the inflection point of the envelope K is detected in order to generate the TK signal 46 by detecting the portion of the detected waveform of the ultrasonic detection signal 42 from the beginning in time. The peak may be detected.

Next, an embodiment in which the ultrasonic wave arrival timing signal is generated from the phases of the ultrasonic wave detection signals of the ultrasonic sensors 7a to 7d will be described with reference to the timing chart of FIG. 5 and the block diagram of FIG. 5 and 6, the same parts as those in FIGS. 3 and 4 are denoted by the same reference numerals, and the description thereof will be omitted.

In the configuration of FIG. 6, the preamplifier circuit 51, the bandpass filter 511, the envelope detection circuit 52, and the gate signal generation circuit 56 are the same as those of FIG. 4, and their operations are the same, but different points. As a result, the phase signal 47 obtained by removing the extra frequency component from the ultrasonic detection signal 42 by the band pass filter 511 and the gate signal 44 generated by the gate signal generation circuit 56 are input to the phase detection circuit 57. This circuit 57 is composed of a zero-cross comparator, etc., and detects the zero-cross point of the phase signal 47 within the period in which the gate signal 44 is open, as shown in FIG.
A TK signal 48 of a pulse train that rises at the rising zero-cross point and falls at the falling zero-cross point is generated. This makes it possible to stably detect the phase at a constant position (number of shots) in the wave packet of the phase signal 47.

Then, the TK signal 48 is input to the arithmetic control circuit 5 as an ultrasonic wave arrival timing signal indicating the ultrasonic wave arrival timing detected from the phase of the ultrasonic wave detection signal 42, and in the above-mentioned configuration, the ultrasonic wave generation means is used. 2 from the rising time of the drive signal 41 to the rising time of the first pulse of the TK signal 48 (zero crossing point of the first rising of the phase signal 47 in the period when the gate signal 44 is open). The ultrasonic wave transmission time from the ultrasonic wave generation means 2 to the ultrasonic wave sensor 7a is measured and detected.

<Explanation of distance between input indicator and sensor and calculation of coordinates> Next, from the ultrasonic wave generating means 2 of the input indicator 1 to each ultrasonic sensor according to the ultrasonic wave transmission time TK obtained as described above. A method of calculating the distance to 7a to 7d and further calculating the coordinates of the position of the ultrasonic wave generating means 2 from the distance will be described. The microcomputer 31 performs this calculation, as described above.

First, assuming that the distance from the ultrasonic wave generating means 2 of the input indicator 1 to the ultrasonic wave sensor 7a is La and the ultrasonic wave propagation velocity in the air is V, La can be calculated by the following equation.

La = VTK (1) This equation relates to one ultrasonic sensor 7a, but the same equation is used for the other three ultrasonic sensors 7b to 7d and the ultrasonic wave generating means 2 of the input indicator 1. The distances Lb to Ld can be similarly obtained.

Next, a method of calculating the coordinates of the position of the ultrasonic wave generating means 2 of the input indicator 1 from these distances will be described. Here, in order to simplify the explanation, a flat plane forming a coordinate input surface will be described. A method of calculating the two-dimensional coordinates (x, y) of the position of the ultrasonic wave generating means 2 of the input indicator 1 on the face plate 6 will be described.

In the above description, four ultrasonic sensors are provided at the four corners of the flat plate 6, but as a simpler configuration, as shown in FIG. 7, two ultrasonic sensors are provided at both ends of one side of the flat plate 6. Since the coordinates can be sufficiently detected even with the configuration in which only the sound wave sensors 7a and 7b are provided, the coordinate calculation method in the case of this configuration will be described first. Even when four ultrasonic sensors are provided, it is needless to say that two of them can be selected and used to calculate the coordinates as follows.

First, from the ultrasonic wave generating means 2 of the input indicator 1 to the vibration sensors 7a and 7b according to the equation (1) described above.
The straight line distances La and Lb to the respective positions are obtained.

Next, based on the linear distances La and Lb, the distance between the ultrasonic sensors 7a and 7b is set to X, and the input indicator 1
The coordinates (x, y) of the position of the ultrasonic wave generating means 2 are calculated from the Pythagorean theorem as follows.

X = X / 2 + (La + Lb) · (La−Lb) / 2X (2) y = √ ((La + Lb) · (La−Lb)) (3) Next, distance information of three ultrasonic sensors A method of calculating the coordinates by using will be described. In this case, as shown in FIG. 8, three ultrasonic sensors 7a to 7c are provided at three corners on the upper surface of the flat plate 6.
May be provided, or four ultrasonic sensors 7a to 7 at four corners.
d may be provided and three of four may be selected and used. Here, the former three configurations will be described.

The coordinate calculation procedure in this case is basically the same as that in the case where there are two ultrasonic sensors. First, based on the equation (1) described above, the ultrasonic wave generating means 2 of the input indicator 1 is first described. The linear distances La, Lb, and Lc from the position to the positions of the ultrasonic sensors 7a, 7b, and 7c are obtained.

Next, assuming that the distance between the ultrasonic sensors 7a and 7b is X and the distance between the sensors 7a and 7c is Y, the distance La,
Based on Lb and Lc, the coordinates (x, y) of the position of the ultrasonic wave generating means 2 of the input indicator 1 are calculated from the Pythagorean theorem as follows.

X = (La + Lb) · (La−Lb) / 2X (4) y = (La + Lc) · (La−Lc) / 2Y (5) The microcomputer 31 of the arithmetic control circuit 5 inputs as described above. The coordinates of the position of the ultrasonic wave generating means 2 of the indicator 1 can be calculated.

In the above description, the distance information of three ultrasonic sensors is used for calculation, but when four ultrasonic sensors are provided as shown in FIG. 1, the distance information of the remaining one sensor is calculated. It may be used to verify the accuracy of the calculated coordinates. In addition, when the distance between the input indicator and the sensor is large, the level of the ultrasonic detection signal decreases and the probability of being affected by noise increases, so that the distance from the input indicator among the four sensors is shorter. It is also possible to select two or three sensors and calculate the coordinates from the distance information. Considering the case where the transmission of ultrasonic waves is blocked not only by the distance from the input indicator but also by the shadow of the hand, etc., two or three from the one with the highest ultrasonic detection signal level among the four sensors. May be selected to calculate the coordinates from the distance information.

Further, although the method of calculating the two-dimensional coordinates has been described above for the sake of simplicity, it is easy to extend it to the calculation of the three-dimensional coordinates, and a description thereof will be omitted.
The coordinate calculation formula may be changed to a three-dimensional calculation formula. That is, even when the input indicator 1 is separated from the flat plate 6, the ultrasonic sensors 7a to 7d are separated from the input indicator 1.
By applying the above-described method of obtaining the two-dimensional coordinates to the three-dimensional coordinate calculation based on the ultrasonic wave transmission time up to, the distance Z from the ultrasonic wave generating means 2 of the input indicator 1 to the input plate 6
Including the three-dimensional coordinates (x,
y, z) can be easily calculated. Here, depending on the purpose of use of the device, the hardware may support three-dimensional input, and means for switching between the two-dimensional coordinate input and the three-dimensional coordinate input may be provided by switching the calculation of the coordinate calculation.

<Description of Ultrasonic Wave Generating Means of Input Indicator> Next, the ultrasonic wave generating means 2 of the input indicator 1 will be described in detail. As described above, the ultrasonic wave generating means 2 is composed of a piezoelectric film that has a lower acoustic impedance and a higher degree of freedom in shape than the ceramic vibrator of the piezoelectric element.

Specifically, the ultrasonic wave generating means 2 is shown in FIG.
It is composed of the piezoelectric film 20 shown in FIG. The piezoelectric film 20 has an elongated parallelogram shape, and in the figure, the short sides 21 and 22 at the left and right ends are the long sides 23 and 2 at the upper and lower ends.
It is inclined with respect to 4. By connecting the portions of the short sides 21 and 22 of the piezoelectric film 20 linearly,
As shown in (b) and (c), the ultrasonic wave generating means 2 has a cylindrical shape. Of course, the length A of the long sides 23 and 24 is substantially the length of the circumference of the ultrasonic wave generating means 2.

Reference numeral 20a is a linear joint between the short sides 21 and 22, and the cylindrical ultrasonic wave generator 2 has one end in the axial direction to the other end (upper end to lower end in the figure). It extends along the direction inclined with respect to the axial direction,
In the circumference of the ultrasonic wave generating means 2, reference numeral C is shown in FIG.
It extends over the range of the arc indicated by.

The short side portions of the piezoelectric film 20 in the joint portion 20a are joined to each other with an adhesive, a resin tape for bonding, or a crimping member sandwiching each other.

The piezoelectric film 20 is composed of a uniaxially stretched polarized film of a polymeric material such as polyvinylidene fluoride (PVDF) or a copolymer of PVDF and trifluoroethylene. A thin film electrode for applying a drive signal from the vibration drive circuit 4 is formed by vapor-depositing aluminum or the like or applying a conductive paint on substantially the entire surfaces of both surfaces of the. The electrodes are connected to the vibration drive circuit 4 by pressure bonding or a conductive paint or other means through the electrode lead-out portion having a small area. Further, the uniaxially stretched direction of the uniaxially stretched polarized film forming the piezoelectric film 20 is the direction along the circumferential direction of the cylindrical shape of the ultrasonic wave generating means 2, that is, the longitudinal direction of the piezoelectric film 20 in FIG. Has become.

The piezoelectricity of the piezoelectric film composed of the uniaxially stretched polarized film exhibits strong anisotropy, and when a driving voltage is applied in the thickness direction, the strain in the uniaxially stretched direction becomes the largest. Therefore, by setting the uniaxial stretching direction to be the direction along the circumferential direction of the cylindrical shape of the ultrasonic wave generating means 2, the ultrasonic wave generating means 2 can measure the dimension of the cylindrical shape in the circumferential direction by applying the drive voltage. Expands and contracts to perform respiratory vibration, and as shown by the arrow in FIG. 11B, ultrasonic waves are radially generated in a direction perpendicular to the outer peripheral surface. In addition, as described above, in FIG. 11, the direction of the ultrasonic wave is indicated by the direction of the arrow, and the sound pressure or amplitude of the ultrasonic wave is indicated by the length of the arrow.

By the way, a linear joint portion 20a in which both ends of the piezoelectric film 20 of the ultrasonic wave generating means 2 are joined together.
Becomes a discontinuous portion in the strain in the uniaxial stretching direction due to an adhesive, a resin tape, a pressure bonding member, or the like depending on the joining method. Therefore, in order to minimize the ultrasonic wave output loss due to the vibration damping, even if the use of the adhesive, the resin tape, the pressure bonding member, etc. is minimized, the generation efficiency of the ultrasonic wave emitted in the air at the joint portion 20a does not decrease. Inevitable.

However, in this embodiment, the joint 2
0a extends from one end to the other end in the axial direction of the cylindrical ultrasonic wave generating means 2 in a direction inclined with respect to the axial direction, and as shown in FIG. Then, the joint portion 20a has a range of an arc having a width significantly larger than its own line width on the circumference of the ultrasonic wave generating means 2 (see FIG. 10).
It extends over the range indicated by the symbol C in (c). Therefore, the influence of the lowering of the ultrasonic wave generation level due to the joint portion 20a does not concentrate in one extremely narrow place in the circumferential direction of the ultrasonic wave generating means 2 as shown in FIG.
As shown in FIG.
As shown in FIG. 1 (b), the joint portion 20 is formed in the circumferential direction.
A large decrease in the ultrasonic wave generation level due to a can be avoided.
Therefore, compared to the conventional example, the ultrasonic wave generation level can be made more uniform in the circumferential direction of the ultrasonic wave generation means 2, and coordinate detection can be performed by the coordinate input by the input indicator 1 equipped with this ultrasonic wave generation means 2. It can be performed more stably and with high accuracy.

The dimension of the piezoelectric film of the ultrasonic wave generating means 2 in the circumferential direction of the cylinder is determined based on the following generally known equation relating to resonance characteristics.

Fr = (1 / (2πr)) √ (Y / ρ) (6) Here, Y is the Young's modulus of the piezoelectric film, ρ is the density, and r is the radius of the cylinder.

<Description of Other Embodiments of Ultrasonic Wave Generation Means>
By the way, the shape of the piezoelectric film 20 of the ultrasonic wave generating means 2 and the shape of the joint portion 20a resulting therefrom are not limited to those of the above-described first embodiment, and are shown in, for example, FIG. 12, FIG. 13, and FIG. 15 described below. The shapes of the second to fourth embodiments may be adopted.

Second Embodiment First, in the second embodiment, as shown in FIG.
The piezoelectric film 20 has a parallelogram shape, and the lengths of the sides 21 and 22 at the left and right ends to be joined are the sides 23 and 2 at the upper and lower ends.
The length is longer than the length A of 4 and is generally shaped so that the sides 21 and 22 are the hypotenuses of right-angled triangles having the sides 24 and 23 as the bases, respectively. Note that a rectangle may be inserted between each of the right triangles. Then, the portions of the sides 21 and 22 are joined linearly to form a cylindrical ultrasonic wave generating means 2 shown in FIG. The linear joint portion 20a between the sides 21 and 22 of the ultrasonic wave generating means 2 extends from one end to the other end in the axial direction of the ultrasonic wave generating means 2 along a direction inclined with respect to the axial direction and has a long length. Thus, the ultrasonic wave generating means 2 having a size of A extends over the entire circumference of the circumference.

The function and effect of such a shape will be described with reference to FIG. In FIG. 14, the sound pressure or amplitude of ultrasonic waves generated by the ultrasonic wave generating means 2 is set to 0 when the joint 20a is not present, and the loss of sound pressure or amplitude of ultrasonic waves generated by the joint 20a is plotted on the vertical axis and the horizontal axis is plotted on the horizontal axis. 2 is a schematic view showing a portion of the ultrasonic wave generating means 2 developed in the circumferential direction.

Here, D shows the loss at the position B of the joint portion 20a in the circumferential direction of the ultrasonic wave generating means 2 shown in FIG. 9 (c) of the ultrasonic wave generating means 2 of the above-mentioned conventional example. is there. In addition, in the first embodiment described above, FIG.
E shows the loss in the existence range C of the joint portion 20a in the circumferential direction of the ultrasonic wave generating means 2 shown in (c). Also, in the second embodiment described above, the ultrasonic wave generation means 2
It is F that indicates the loss in the existing range of the joint portion 20a in the circumferential direction, that is, in the range of the entire circumference of the length A shown in FIG.

As can be seen from this, as the existence range of the joint portion 20a in the circumferential direction of the ultrasonic wave generating means 2 becomes wider, the loss due to the joint portion 20a becomes smaller and the ultrasonic wave generation level over the entire circumference becomes smaller. Improves uniformity. Therefore,
According to the second embodiment, the loss due to the joint portion 20a is the smallest, the uniformity of the ultrasonic wave generation level over the entire circumference is also the best, and the coordinate detection accuracy can be improved.

Third Embodiment Next, in the third embodiment, as shown in FIG. 13A, the piezoelectric film 20 constituting the ultrasonic wave generating means 2 is
It is an elongated quadrilateral, and the opposing long sides 23 and 24 are straight lines, but the opposing short sides 21 and 22 are curved. Of course, the curved shapes of the short sides 21 and 22 are the same.
The short sides 21 and 22 are linearly joined to each other as shown in FIG.
The ultrasonic wave generation means 2 including the cylindrical piezoelectric film 20 shown in FIG. The shape of the linear joint portion 20a between the short sides 21 and 22 is, of course, short.
2 has the same curved shape as that of 2, and extends from one end to the other end in the axial direction of the ultrasonic wave generating means 2 over the range of the arc indicated by the symbol C on the circumference of the ultrasonic wave generating means 2, and the ultrasonic wave is generated as the both ends are approached. It becomes closer to being perpendicular to the axial direction of the means 2, and becomes closer to being parallel to the axial direction as it approaches the center. However, even in the center, it is not parallel to the axial direction and is slightly inclined.

The loss of sound pressure or amplitude of ultrasonic waves generated by the joint 20a in the existing range C of the joint 20a on the circumference of the ultrasonic wave generating means 2 is described above.
4 is denoted by the reference symbol G. By the way, here
For convenience of comparison, it is assumed that the existence range C of the joint 20a matches the first embodiment of FIG. 10 described above.

As can be seen from the loss G of the third embodiment and the loss E of the first embodiment shown in FIG.
In the case of the embodiment of the present invention, the loss in the central portion of the range C is larger than that of the first embodiment, but the loss of both ends of the range C is smaller than that of the first embodiment, and the change is gentle. There is continuity with other ranges.

Therefore, according to the third embodiment, if the size of the loss at the center of the existing range C of the joint 20a is within a certain allowable range in terms of coordinate detection accuracy, the joint 20
Since it is possible to suppress a rapid change in the ultrasonic wave generation level before and after the boundary of the existence range C of a, it is possible to prevent the occurrence of an error such as a sudden coordinate jump and improve the coordinate detection accuracy.

Fourth Embodiment Next, in the fourth embodiment, as shown in FIG. 15A, two piezoelectric films 20 and 20 'having the same shape and the same size.
Are joined together to form the cylindrical ultrasonic wave generating means 2 shown in FIGS. 15 (b) and 15 (c).

In the piezoelectric films 20, 20 ', the lengths of the sides 21, 22, 21', 22 'at the left and right ends are longer than the lengths of the sides 23, 24, 23', 24 'at the upper and lower ends, respectively. The sides 21, 22, 21 ', 22' are shaped so as to be the respective oblique sides of a right triangle having the sides 24, 23, 24 ', 23' as the bases. Note that a rectangle may be inserted between each of the right triangles. The portions 21 and 22 'of the piezoelectric films 20 and 20' and the portions 22 and 21 'of the piezoelectric films 20 and 20' are linearly joined to form a cylindrical ultrasonic wave generating means 2.

In the ultrasonic wave generating means 2, two linear joint portions 20a and 20a 'are formed. Joints 20a, 20
Each a ′ extends from one end to the other end in the axial direction of the cylinder of the ultrasonic wave generating means 2 in the direction inclined in the axial direction, and extends over the half circumference of the circumference of the ultrasonic wave generating means 2.
Joints 20a, 20 on the circumference of the ultrasonic wave generating means 2
The range of existence of a'is of course deviated from each other by a half circumference, and the two are combined so that the joint exists in the range of the entire circumference of the ultrasonic wave generating means 2.

According to such a fourth embodiment, as shown in FIG.
In addition to obtaining the same effect as the second embodiment of No. 2,
Joining portions 20a, 20 with respect to the axial direction of the ultrasonic wave generating means 2
The inclination angle of a'can be made smaller than that in the second embodiment. Therefore, the handling is simplified in the cutting work and the joining work of the piezoelectric film in the production of the ultrasonic wave generating means 2, and the cost is reduced.

Needless to say, the ultrasonic wave generating means 2 may be formed by joining three or more piezoelectric films into a cylindrical shape.

<Description of Fixing Structure of Ultrasonic Wave Generating Means> Next, regarding the fixing structure of the ultrasonic wave generating means 2 to the tip portion of the input indicator 1, the first to sixth embodiments will be described with reference to FIGS. explain.

First Embodiment FIG. 17 shows the first embodiment of the fixing structure of the ultrasonic wave generating means 2.
This will be described with reference to (a) and (b). 17 (a), (b)
In the figure, 14 is the tip of the input indicator 1 whose main body is not shown here, and is formed as a cylindrical member having a diameter slightly smaller than that of the cylindrical ultrasonic wave generating means 2 made of the piezoelectric film described above. The ultrasonic wave generating means 2 is fitted on the outer side of the tip portion 14 and fixed by the fixing member 12.

The fixing member 12 is, for example, a metal clip-like member, is formed in a linear shape that is curved in an arc shape as a whole, is attached to the tip portion 14, and is a part of the piezoelectric film 20 of the ultrasonic wave generating means 2. The ultrasonic wave generating means 2 is fixed by elastically pressing it against the outer peripheral surface of the tip portion 14 with the pinch sandwiched therebetween. The fixing member 12 is attached in the axial direction of the ultrasonic wave generating means 2, that is, in the direction inclined with respect to the axial direction of the tip end portion 14, and the ultrasonic wave generating means 2 is extended over the entire width in the axial direction.
It is pressed in a line against.

The fixing portion of the ultrasonic wave generating means 2 which is fixed to the tip end portion 14 by pressure contact with the fixing member 12 has a continuous linear shape, and the axial direction of the ultrasonic wave generating means 2 is from the one end to the other end. It will extend along the direction inclined with respect to the direction.

Here, the fixing portion becomes a discontinuous portion due to the fixing member 12 in the strain in the uniaxial stretching direction of the piezoelectric film 20 of the ultrasonic wave generating means 2, like the joint portion 20a of the piezoelectric film 20 described above. The generation efficiency of ultrasonic waves emitted in the air at the fixed portion is unavoidable.

However, in this embodiment, the fixing portion extends from one end to the other end of the cylindrical ultrasonic wave generating means 2 in the axial direction along the direction inclined with respect to the axial direction, as shown in FIG. As shown in b), when viewed in the axial direction, the fixed portion 12a has a circular arc range having a width significantly larger than the line width of the fixed portion 12a itself on the circumference of the ultrasonic wave generating means 2 (FIG. 17 (b)). It extends over the range C). Therefore, the influence of the lowering of the ultrasonic wave generation level due to the fixing portion 12a is not concentrated in one extremely narrow place in the circumferential direction of the ultrasonic wave generating means 2 as shown in FIG. It is dispersed and relaxed in the range of the arc of the width, and as shown in FIG. 18 (b), a large decrease in the ultrasonic wave generation level due to the fixing portion 12a in the circumferential direction can be avoided.

Therefore, the ultrasonic wave generation level can be made more uniform in the circumferential direction of the ultrasonic wave generating means 2 as compared with the fixing structure of the ultrasonic wave generating means 2 of the conventional example. Coordinates can be detected more stably and with high accuracy by inputting coordinates by the input indicator 1 to which the sound wave generator 2 is fixed. That is, according to the fixing structure of the ultrasonic wave generating means 2 of the present embodiment, the function and effect corresponding to the first embodiment relating to the shape of the bonding portion 20a of the piezoelectric film 20 of the ultrasonic wave generating means 2 described above with reference to FIG. Is obtained.

In the above description, the fixing member 12 is configured such that the ultrasonic wave generating means 2 is linearly pressed against the tip portion to form the fixing portion 12a in a continuous linear shape.
As shown in (c), the fixing portion 12a is the ultrasonic wave generating means 2
The fixing member 12 has a plurality of pressing portions distributed so as to be dispersed in a plurality of dots (which may be a short linear shape or another shape) arranged along a direction inclined with respect to the axial direction of The ultrasonic wave generating means 2 may be brought into pressure contact with the tip portion 14 by the pressing portion. Furthermore, the plurality of fixing portions 12a are not shown in FIG.
It does not need to be lined up like 7 (c), and may be randomly distributed. This also applies to other embodiments described below.

The method of fixing the ultrasonic wave generating means 2 is not limited to the above-mentioned method, and it goes without saying that another method such as adhesion may be used, and this also applies to other embodiments.

Further, since the tip portion 14 of the input indicator 1 is a hollow cylinder and has an opening, the input plate 6 of the input indicator 1 is provided.
A switch or the like for switching the coordinate input mode such as pen-up or pen-down depending on the presence or absence of contact with the tip may be incorporated in the tip portion 14.

Second Embodiment Next, FIG. 19 shows a second embodiment of the fixing structure of the ultrasonic wave generating means 2. In this case, the ultrasonic wave generating means 2 is fixed to the distal end portion 14 of the input indicator 1 by a coil spring-shaped fixing member (not shown) or adhesion,
The fixing portion 12a has a linear shape and extends from one end to the other end in the axial direction of the ultrasonic wave generating means 2 in a direction inclined with respect to the axial direction, and over the entire circumference of the circumference of the ultrasonic wave generating means 2. It is designed to extend.

According to the fixing structure of the second embodiment, the joint portion 20 of the ultrasonic wave generating means 2 described above with reference to FIG. 12 is used.
The operational effect corresponding to the second embodiment relating to the shape of a can be obtained.

That is, the conventional example of FIG. 16 and the first example of FIG.
Of the ultrasonic wave generating means 2 in the circumferential direction of the ultrasonic wave generating means 2 in each of the above embodiment and the second embodiment of FIG. D of the conventional example (FIG. 9) in FIG. 14 showing the loss due to the joint portion 20a of the film 20,
E of the first embodiment (FIG. 10) and the second embodiment (FIG. 1)
It corresponds to F of 2).

That is, according to the second embodiment of the fixing structure of the ultrasonic wave generating means 2, the loss due to the fixing portion 12a is minimized, and the ultrasonic wave generating level over the entire circumference of the ultrasonic wave generating means 2 is reduced. Is also the best, and the coordinate detection accuracy can be improved.

Third Embodiment Next, FIG. 20 shows a third embodiment of the fixing structure of the ultrasonic wave generating means 2. In this case, the ultrasonic wave generating means 2 is fixed to the tip portion 14 of the input indicator 1 by a fixing member (not shown) or adhesion, and the fixing portion 12a thereof is
The curve has a shape corresponding to the joint portion 20a in the third embodiment related to the shape of the joint portion 20a of the ultrasonic wave generating means 2 described above with reference to FIG.

That is, the fixed portion 12a extends from one end to the other end in the axial direction of the ultrasonic wave generating means 2, extends over the range of an arc indicated by the symbol C on the circumference of the ultrasonic wave generating means 2, and is provided at both ends. The curved shape is such that it becomes closer to being perpendicular to the axial direction of the ultrasonic wave generating means 2 as it approaches, and becomes closer to being parallel to the axial direction as it approaches the center.

According to the third embodiment of the fixing structure as described above, the fixing portion 12 in the circumferential direction of the ultrasonic wave generating means 2 is provided.
The loss of the sound pressure or amplitude of the ultrasonic waves generated by a (the loss of the existing range C) is the loss due to the joint portion 20a of the piezoelectric film 20 of the ultrasonic wave generating means 2 described in the third embodiment in FIG. This corresponds to G in FIG. 13). Therefore, the function and effect corresponding to the third embodiment relating to the shape of the joint portion 20a can be obtained.

That is, it is possible to suppress a sudden change in the ultrasonic wave generation level before and after the boundary of the existing range C of the fixed portion 12a in the circumferential direction of the ultrasonic wave generating means 2, and thereby to prevent a sudden coordinate jump. It is possible to prevent the occurrence of an error and improve the coordinate detection accuracy.

Fourth Embodiment Next, FIGS. 21A and 21B show a fourth embodiment of the fixing structure of the ultrasonic wave generating means 2. In this embodiment,
The ultrasonic wave generating means is combined with the first embodiment (FIG. 10) relating to the shape of the joint portion 20a of the ultrasonic wave generating means 2 described above and the first embodiment (FIG. 17) of the fixing structure of the ultrasonic wave generating means 2. The linear joint portion 20 inclined with respect to the axial direction of 2
The position of the linear fixing portion formed by a and the fixing member 12 is made to coincide with each other.

In this case, in particular, the fixing member 12 serves also as a joining member for joining the parallelogram-shaped piezoelectric film 20 of the ultrasonic wave generating means 2 by sandwiching both side portions at both ends and crimping them together at the joint portion 20a. By doing so, it is possible to reduce the number of parts, minimize the loss occurrence portion (range) in the ultrasonic wave generation on the circumference of the ultrasonic wave generating means 2, and to measure the circumferential direction of the ultrasonic wave generating means 2. It is possible to improve the uniformity of the ultrasonic wave generation level in
The coordinate detection accuracy can be improved.

Fifth Embodiment Next, FIG. 22 shows a fifth embodiment of the fixing structure of the ultrasonic wave generating means 2. Ultrasonic wave generation means 2 of the present embodiment
In the above, a protruding portion 20b protruding in one axial direction (downward in the drawing) of the cylindrical piezoelectric film 20 forming the same is formed. The protrusion 20b has a tongue shape, has a width in the circumferential direction of the ultrasonic wave generating means 2, and is physically and electrically continuous with the cylindrical portion of the piezoelectric film 20. That is, it is continuous as a vibrating body. And this protrusion 2
The central portion of 0b is fixed to the tip portion 14 of the input indicator 1 by an elongated rectangular fixing member 12 that is curved in an arc shape, whereby the ultrasonic wave generating means 2 is fixed to the tip portion 14. The fixing portion fixed by the fixing member 12 of the ultrasonic wave generating means 2 has a shape corresponding to the fixing member 12,
Since the longitudinal direction of the fixing member 12 is along the circumferential direction of the ultrasonic wave generating means 2, the fixing member 12 extends over a part of the arc of the circumference.

According to the present embodiment as described above, the cylindrical portion, which is the main vibrating body of the ultrasonic wave generating means 2, is not directly fixed to the tip portion 14, but the protruding portion 20b is fixed. It is possible to reduce the influence of the ultrasonic wave generation efficiency due to the fixed portion of the generating means 2. Further, since the fixed portion extends over a part of the circular arc range of the circumference of the ultrasonic wave generating means 2, the influence of the lowering of the ultrasonic wave generation level due to the fixed part is dispersed and mitigated in the range, The ultrasonic wave generation level is made uniform in the circumferential direction. Therefore, the coordinate detection accuracy can be improved.

Sixth Embodiment Next, FIG. 23 shows a sixth embodiment of the fixing structure of the ultrasonic wave generating means 2. In the present embodiment shown here, in the configuration of the fifth embodiment of FIG. 22 described above, the fixing member 12 that fixes the protruding portion 20b of the ultrasonic wave generating means 2 to the tip portion 14 of the input indicator 1 is a conductor. The electrode is electrically connected to the outside (vibration drive circuit 4) by electrically connecting to a thin-film electrode (not shown) on the surface of the piezoelectric film 20 of the ultrasonic wave generation means 2 by pressure contact or the like as a T-shape. It is configured so as to also serve as an electrode lead-out portion for connection.

As shown by reference numeral 12 ', this fixing member 12 may be provided on the back surface side of the projecting portion 20b so that the projecting portion 20b is sandwiched between the front surface and the back surface and fixed to the tip portion 14, or the front surface portion. Only the fixing member 12 is provided as a take-out portion of the electrode of one polarity, the tip portion 14 is made of a conductor, and the back surface of the ultrasonic wave generating means 2 is pressed against the fixing portion to make the tip portion 14 of the other polarity. It may be used as an electrode take-out portion. Incidentally, 16 and 16 'are fixing members 12 and 1
It is a lead wire connected to 2 '.

According to the present embodiment as described above, compared to the case where the fixing portion and the electrode lead-out portion of the ultrasonic wave generating means 2 are provided separately, it is possible to reduce the influence of the reduction in the vibration generation level due to each.

[0109]

As is apparent from the above description, according to the present invention, an input indicator for a coordinate input device of the aerial ultrasonic system is provided, in which the end portions of one or a plurality of piezoelectric films are connected to each other. In an input indicator having an ultrasonic wave generating means configured as a cylindrical shape by being joined linearly, the influence of the ultrasonic wave generation level lowering due to the linear joint portion between the end portions of the ultrasonic wave generating means Disperses in the circumferential direction and relaxes,
The ultrasonic wave generation level can be made more uniform in the circumferential direction.

Further, in the input indicator having the ultrasonic wave generating means made of a cylindrical piezoelectric film fixed to the tip portion, the influence of the ultrasonic wave generation level lowering by the fixing portion of the ultrasonic wave generating means fixed to the tip portion. Can be dispersed and relaxed in the circumferential direction of the ultrasonic wave generating means, and the ultrasonic wave generation level can be made more uniform in the circumferential direction.

Further, it is possible to provide an excellent aerial ultrasonic wave type coordinate input device which can stably perform coordinate detection with high accuracy by using the input indicator according to the present invention.

[Brief description of drawings]

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

FIG. 2 is a block diagram showing a configuration of an arithmetic control circuit of the device.

FIG. 3 is a timing chart of each signal involved in signal processing in the first embodiment of the detection signal processing circuit of the same device.

FIG. 4 is a block diagram showing a configuration of a first embodiment of a detection signal processing circuit of the same device.

FIG. 5 is a timing chart of each signal related to signal processing in the second embodiment of the detection signal processing circuit of the same device.

FIG. 6 is a block diagram showing a configuration of a second embodiment of a detection signal processing circuit of the same device.

FIG. 7 is an explanatory diagram illustrating a coordinate calculation method using two ultrasonic sensors in the same apparatus.

FIG. 8 is an explanatory diagram illustrating a coordinate calculation method using the same apparatus using three ultrasonic sensors.

FIG. 9 is an explanatory diagram showing a shape and a joining structure of a piezoelectric film of an ultrasonic wave generating means including a piezoelectric film of a conventional input indicator.

FIG. 10 is an explanatory view showing a shape and a joining structure of a piezoelectric film in the ultrasonic wave generating means of the input indicator according to the first embodiment of the present invention.

FIG. 11 is an explanatory diagram showing how the ultrasonic wave generation level is lowered by the piezoelectric film bonding portion in the circumferential direction of the conventional ultrasonic wave generation means and the ultrasonic wave generation means of the first embodiment.

FIG. 12 is an explanatory diagram showing a shape and a bonding structure of a piezoelectric film in a second embodiment of an ultrasonic wave generating means.

FIG. 13 is an explanatory diagram showing a shape and a bonding structure of a piezoelectric film in a third embodiment of an ultrasonic wave generating means.

FIG. 14 is a diagram showing a sound pressure or amplitude loss of ultrasonic waves generated by a piezoelectric film joint portion in the circumferential direction of each of the conventional ultrasonic wave generating means and the ultrasonic wave generating means of each embodiment of the present invention. .

FIG. 15 is an explanatory diagram showing a shape and a bonding structure of a piezoelectric film in a fourth embodiment of an ultrasonic wave generating means.

FIG. 16 is an explanatory view showing a fixing structure of ultrasonic wave generating means of a conventional input indicator.

FIG. 17 is an explanatory view showing the first embodiment of the fixing structure of the ultrasonic wave generating means of the input indicator and its modification according to the present invention.

FIG. 18 is an explanatory view showing how the ultrasonic wave generation level is lowered by the fixing portion in the circumferential direction of the ultrasonic wave generating means in the conventional fixing structure of the ultrasonic wave generating means and the fixing structure of the first embodiment.

FIG. 19 is a side view showing a second embodiment of the fixing structure of the ultrasonic wave generating means.

FIG. 20 is a side view showing a third embodiment of the fixing structure of the ultrasonic wave generating means.

FIG. 21 is an explanatory view showing a fourth embodiment of the fixing structure of the ultrasonic wave generating means.

FIG. 22 is a perspective view showing a fifth embodiment of the fixing structure of the ultrasonic wave generating means.

FIG. 23 is a perspective view showing a sixth embodiment of the fixing structure of the ultrasonic wave generating means.

[Explanation of symbols]

1 input indicator 2 Ultrasonic generator 4 Vibration drive circuit 5 Operation control circuit 6 flat plate 7a-7d ultrasonic sensor 8 Detection signal processing circuit 10 display 11 Display drive circuit 12 Fixing member for ultrasonic wave generation means 12a Fixed part of ultrasonic wave generating means 14 Tip of input indicator 20,20 'Piezoelectric film 20a, 20a 'Joint portion of piezoelectric film 31 Microcomputer 33 timer 34a to 34d Latch circuit 51 Preamplifier circuit 52 Envelope detection circuit 53 Second-order differentiation circuit 54 Inflection point detection circuit 56 gate signal generation circuit 57 Phase detection circuit

Continued front page    (72) Inventor Katsuyuki Kobayashi             3-30-2 Shimomaruko, Ota-ku, Tokyo             Non non corporation F term (reference) 2F068 AA03 AA04 FF04 FF25 GG01                       KK14 KK18 LL29 LL30 QQ08                       QQ12                 5B068 AA04 AA22 AA36 BB21 BD02                       BD11 BD17 BE08 CC06                 5B087 AA02 CC21 CC26 CC47

Claims (11)

[Claims] 1. An input indicator having an ultrasonic wave generating means, which is used to indicate a position for inputting coordinates by an aerial ultrasonic wave coordinate input device, wherein one or more ultrasonic wave generating means are provided. The end portion of the piezoelectric film is linearly joined to form a cylindrical shape, and the linear joint portion between the end portions extends from one end to the other end in the axial direction of the ultrasonic wave generating means. An input indicator, which extends over at least a part of the arc of the circumference of the ultrasonic wave generating means. 2. The linear joint between the ends of the piezoelectric film of the ultrasonic wave generating means is formed along the direction inclined from the one end to the other end in the axial direction of the ultrasonic wave generating means. The input indicator according to claim 1, wherein the input indicator extends. 3. The ultrasonic wave generating means, wherein the linear joint between the end portions of the piezoelectric film extends over the entire circumference of the ultrasonic wave generating means.
Input indicator described in. 4. An input indicator used to indicate a position for inputting coordinates by an aerial ultrasonic type coordinate input device, wherein an ultrasonic wave generating means made of a cylindrical piezoelectric film is fixed to a tip portion. In the input indicator, the input indicator is characterized in that the fixing portion of the ultrasonic wave generating means fixed to the tip portion exists over the range of an arc of at least a part of the circumference of the ultrasonic wave generating means. . 5. The input indicator according to claim 4, wherein the fixing portion of the ultrasonic wave generating means is present along a direction inclined with respect to the axial direction of the ultrasonic wave generating means. 6. The input indicator according to claim 4, wherein the fixing portion of the ultrasonic wave generating means is present over the entire circumference of the circumference of the ultrasonic wave generating means. 7. The ultrasonic wave generation means is configured as a cylindrical shape by joining the ends of one or a plurality of piezoelectric films linearly, and connecting the ends of the piezoelectric film to each other. 5. The input indicator according to claim 4, wherein the joining means for joining in a linear shape also serves as a fixing means for fixing the ultrasonic wave generating means to the tip portion of the input indicator. 8. A cylindrical piezoelectric film forming the ultrasonic wave generating means is formed with a protrusion protruding in one axial direction, and at least a part of the protrusion serves as the fixing portion and the input indicator. The input indicator according to claim 4, wherein the input indicator is fixed to the tip of the. 9. The input indicator according to claim 4, wherein the fixing means for fixing the ultrasonic wave generating means to the tip portion of the input indicator also serves as an electrode extracting portion of the ultrasonic wave generating means. . 10. The piezoelectric film of the ultrasonic wave generating means is a uniaxially stretched polarized film, and the uniaxially stretching direction is a direction along the circumferential direction of the ultrasonic wave generating means. 9. The input indicator according to any one of 9 to 9. 11. The input indicator according to any one of claims 1 to 10, and the input indicators are arranged at different positions for detecting ultrasonic waves emitted in the air from the ultrasonic wave generation means of the input indicators. A plurality of ultrasonic wave detecting means, and a plurality of ultrasonic wave detecting signals of the plurality of ultrasonic wave detecting means are processed to generate a plurality of timing signals indicating respective arrival timings of the ultrasonic waves to the plurality of ultrasonic wave detecting means. A signal processing means, a clocking means for timing each of the transmission times of the ultrasonic waves from the ultrasonic wave generating means of the input indicator to the plurality of ultrasonic wave detecting means by the plurality of timing signals, and the timekeeping means. A coordinate input device comprising: a calculation means for calculating the coordinates of the position of the ultrasonic wave generation means of the input indicator based on each of the ultrasonic wave transmission times.