JPH0614309B2 - Coordinate input device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial application] The present invention relates to a coordinate input device, and more particularly to the vibration transmission of the vibration pen by detecting the vibration input from the vibration pen by a plurality of sensors provided on the vibration transmission plate. The present invention relates to a coordinate input device that detects coordinates on a board.

[Prior Art] Conventionally, a coordinate input device using various input pens, tablets, and the like has been known as a device for inputting handwritten characters, figures, and the like into a processing device such as a computer. In this type of system, the input image information including characters and figures is output to a display device such as a CRT display or a recording device such as a printer.

The following various methods are known for detecting the coordinates of the tablet of this type of device.

1) A method of detecting a change in resistance value of a sheet material that is arranged to face the resistance film.

2) A method of detecting electromagnetic or electrostatic induction of a conductive sheet or the like arranged opposite to each other.

3) A method of detecting ultrasonic vibration transmitted from the input pen to the tablet.

In the above methods 1) and 2), it is difficult to form a transparent tablet because a resistance film or a conductor film is used. On the other hand, in the method of 3), since the tablet can be made of a transparent material such as an acrylic plate or a glass plate, therefore, the operation can be performed by placing the input tablet on the liquid crystal display etc. so that it can be used as if writing an image on paper. A coordinate input device with a good feeling can be configured.

[Problems to be Solved by the Invention] In the above ultrasonic vibration method, in order to input vibration to the tablet, a vibrating pen including a vibrator including a piezoelectric element is used. In order to efficiently transmit the vibration, a method of transmitting the vibration of the vibrator of the vibrating pen to the vibration transmitting plate via the horn member has been considered.

When the vibration of the oscillator is transmitted through the horn, the horn and the oscillator must form a resonance system with respect to the oscillation frequency in order not to impair the vibration transmission efficiency. The joining surface is considered to be a plane.

Adhesion may be considered as a method of connecting the vibrator and the horn, but if an adhesive is interposed in such a vibration system, vibration may be absorbed depending on the amount and quality of the adhesive,
Alternatively, there may be a problem that the vibration transfer characteristics vary depending on the amount of adhesive for each product. Since such variations in characteristics greatly affect the coordinate detection accuracy,
It's serious. In order to eliminate the variation, inspection may be performed after the completion of the vibrating pen, but it is quite difficult to control the adhesive state to be constant, and the yield may decrease.

As a method other than bonding, crimping with a spring etc. can be considered, but in this method the coupling surface is flat as described above, so not only can the precision of the coupling position between the vibrator and the horn be kept high, but it can also be used. There is a possibility that a positional deviation may occur inside and the detection accuracy may be reduced.

[Means for Solving the Problems] In order to solve the above problems, according to the present invention, the vibration transmitted to the vibration transmission member by contacting the vibration input means is provided in the vibration transmission member. In the coordinate input device for detecting the contact coordinate position of the vibration input means to the vibration transmitting member, the vibration input means includes a vibration generating element for generating vibration, and the vibration generating element. A horn member that transmits the vibration from the vibration transmitting member to the vibration transmitting member; and a spring member that presses the vibration generating element to the horn member, and the horn member is attached to the large end surface of the horn member that is joined to the vibration generating element. And a positioning member for positioning and fixing the vibration generating element are integrally formed, and the spring member has a rear end surface facing a joint surface of the vibration generating element with the horn member. Adopting a configuration in which positioning portion fitted are formed by.

[Operation] A positioning member integrally formed on the large end surface of the horn member,
The horn member and the vibration generating element can be reliably positioned and fixed by the positioning portion of the spring member that presses the vibration generating element against the horn member and is fitted to the rear end surface of the vibration generating element.

[Examples] Hereinafter, the present invention will be described in detail based on examples shown in the drawings.

FIG. 1 shows the structure of an information input / output device adopting the present invention. The device of FIG. 1 not only detects coordinates but also displays input information. That is, the illustrated information input device causes the input tablet composed of the vibration transmission plate 8 to input coordinates by the vibration pen 3, and the display 11 'composed of the CRT arranged on the input tablet according to the input coordinate information. The input image is displayed.

In the figure, reference numeral 8 is a vibration transmission plate made of acrylic, glass plate or the like, and transmits the vibration transmitted from the vibration pen 3 to the vibration sensor 6 provided at three corners thereof. In this embodiment, the coordinate of the vibration pen 3 on the vibration transmission plate 8 is detected by measuring the transmission time of the ultrasonic vibration transmitted from the vibration pen 3 to the vibration sensor 6 via the vibration transmission plate 8.

The vibration transmitting plate 8 has its peripheral portion supported by an antireflection material 7 made of silicon rubber or the like in order to prevent the vibration transmitted from the vibrating pen 3 from being reflected at the peripheral portion and returning toward the central portion. ing.

The vibration transmitting plate 8 is arranged on a display device 11 'capable of dot display, such as a CRT (or a liquid crystal display device), and is adapted to perform dot display at a position traced by the vibration pen 3. That is, a dot display is performed at a position on the display 11 'corresponding to the detected coordinates of the vibrating pen 3, and an image composed of elements such as points and lines input by the vibrating pen 3 is written as if on paper. Appears after the locus of the vibrating pen as you did.

In addition, according to such a configuration, a menu is displayed on the display 11 ', the menu item is selected by the vibrating pen, or a prompt is displayed to bring the vibrating pen 3 into contact with a predetermined position. Can also be used.

The vibration pen 3 that transmits ultrasonic vibrations to the vibration transmission plate 8 is
It has a vibrator 4 formed of a piezoelectric element or the like inside, and transmits the ultrasonic vibration generated by the vibrator 4 to the vibration transmission plate 8 via the horn portion 5.

FIG. 2A shows the structure of the vibrating pen 3.

In the figure, reference numeral 21 is a pen shaft-shaped case of the vibrating pen 3, and a horn portion 5 is fixed to a tip portion thereof. The horn portion 5 has an exponential shape in order to efficiently transmit the vibration of the vibrator 4 to the vibration transmission plate 8. That is, the cross-sectional area of the horn portion 5 is configured to change exponentially from the root to the tip. The acoustic impedance of the horn unit 5 is set so as to form a resonance system with the vibrator 4.

In FIG. 2 (A), a convex portion 26 is provided as a positioning member in the central portion of the rear end of the horn portion 5 which is connected to the vibrator 4. The convex portion 26 is configured to fit into a concave portion having substantially the same inner diameter provided at the front end of the cylindrical vibrator 4.

The convex portion 26 may be formed integrally with the horn portion 5, or may be formed separately from a material having a mass sufficiently smaller than that of the horn portion 5, and may be configured to be press-fitted into the horn portion 5.

In this embodiment, the vibrator 4 and the horn portion 5 are not fixed by adhesion, but are pressed against each other by the spring 24 fixed to the horn portion 5. As with the horn portion 5, a convex portion 23 is provided as a positioning portion at the rear end portion of the vibrator 4, and this convex portion is provided in the spring 2
The spring 24 and the vibrator 4 are positioned and held so that the spring 24 and the vibrator 4 do not shift by being fitted in a hole provided in the central portion of 4.

According to the above configuration, the horn portion 5 and the vibrator 4 are positioned via the convex portion 26 as a positioning portion and further fixed by pressure contact with the spring 24. The spring 24 and the vibrator 4 also serve as the positioning portion. By being positioned through the convex portion 23, the vibrator 4 and the horn portion 5 can be fixed to each other in an accurate positional relationship without causing positional displacement.
Moreover, in the above configuration, since the fixing is not performed by adhesion, the vibration is not absorbed by the adhesive and the vibration transmission characteristic of the vibration pen 3 does not vary.

Further, if the convex portions 23 and 26 as the positioning portions are formed to have a sufficiently small mass, the vibration transmission between the vibrator 4 and the horn portion 5 will not be impaired.

The connecting structure of the vibrator 4 of the vibrating pen 3 and the horn portion 5 is not limited to the above-mentioned structure, and the connecting structure shown in FIG.
You may use the structure as shown in (C).

In the structure of FIG. 2 (B), a cylindrical vibrator 4 is used, and a concave portion is formed in the rear end portion of the horn portion 5 and the pressure contact portion of the spring 24 so as to hold both end portions of the vibrator 4. 27A, 27
B are provided respectively. Each recess 27A, 27B
Has an inner diameter substantially the same as the diameter of the vibrator 4, and is fitted with the vibrator 4.

Further, in the case of FIG. 2 (C), the vibrator 4 is formed into a hollow cylindrical shape, and the horn portion is fitted to the front end portion and the rear end portion of the hollow portion 28 provided in the length direction thereof. 5 and the press contact portion of the spring 24 are provided with convex portions 29A and 29B, respectively.

With the structure as described above, the same effect as described above can be obtained.

The vibrator 4 of the vibrating pen 3 is driven at a predetermined frequency by the vibrator driving circuit 2.

The electric drive signal generated by the drive circuit 2 is converted into mechanical ultrasonic vibration by the vibrator 4 and transmitted to the diaphragm 8 via the horn unit 5.

The vibration frequency of the vibrator 4 is selected to a value capable of generating a plate wave on the vibration transmission plate 8 such as acrylic or glass. Further, when driving the vibrator, the second
A vibration mode is selected in which the vibrator 4 mainly vibrates in the vertical direction of FIG. Further, by setting the vibration frequency of the vibrator 4 as the resonance frequency of the vibrator 4, it is possible to perform efficient vibration conversion.

The elastic wave transmitted from the vibrating pen 3 configured as described above to the vibration transmission plate 8 is a plate wave, and is less affected by scratches or obstacles on the surface of the vibration transmission plate 8 than surface waves. Has the advantage.

Again, in FIG. 1, the vibration sensor 6 provided at the corner of the vibration transmission plate 8 is also composed of a mechanical-electrical conversion element such as a piezoelectric element. The output signal of each of the three vibration sensors 6 is input to the waveform detection circuit 6 and converted into a detection signal which can be processed by the arithmetic control circuit 1 in the subsequent stage. Arithmetic control circuit 1
Performs the process of measuring the vibration transmission time, and detects the coordinate position of the vibration pen 3 on the vibration transmission plate 8.

The detected coordinate information of the vibrating pen 3 is processed in the arithmetic control circuit 1 according to the output system by the display 11 '.
That is, the arithmetic control circuit controls the output operation of the display 11 'via the video signal processing device 10 based on the input coordinate information.

FIG. 3 shows the structure of the arithmetic control circuit 1 of FIG.

The microcomputer 11 has an internal counter, ROM and RAM built therein. The microcomputer 11 gives a start signal for starting the drive of the vibrator drive circuit 2 to the drive signal generation circuit 12, and also starts a counter 13 for measuring the vibration transmission time in synchronization with the start of vibration.

The count value of the counter 13 is latched by the microcomputer 11 in the latch circuit 14.

On the other hand, the waveform detection circuit 9 outputs timing information of the detection signal for measuring the vibration transmission time for coordinate detection from the output of the vibration sensor 6 as described later.

The timing signal input from the waveform detection circuit 9 is input to the input port 15, and the determination circuit 16 causes the latch circuit 1 to operate.
The count value in 4 is compared and the result is transmitted to the microcomputer 11. That is, the vibration transmission time is expressed as a latch value of the output data of the counter 13, and the coordinate calculation is performed based on this vibration transmission time value.

The output control process of the display 11 'is performed via the input / output port 18.

FIG. 4 illustrates a detection waveform input to the waveform detection circuit 9 of FIG. 1 and a vibration transmission time measuring process based on the detection waveform.

In FIG. 4, reference numeral 41 indicates a drive signal pulse applied to the vibrating pen 3. The ultrasonic vibration transmitted to the vibration transmission plate 8 from the vibration pen 3 driven by such a waveform passes through the inside of the vibration transmission plate 8 and is detected by the vibration sensor 6.

After traveling through the vibration transmitting plate 8 for a time tg corresponding to the distance to the vibration sensor 6, the vibration reaches the vibration sensor 6. Reference numeral 42 in FIG. 4 indicates a signal waveform detected by the vibration sensor 6. With respect to the plate wave used in this embodiment, the relationship between the envelope 421 and the phase 422 of the detected waveform with respect to the propagation distance in the vibration transmission plate 8 changes according to the transmission distance during vibration transmission.

Here, it is assumed that the speed at which the envelope advances is the group speed Vg and the phase speed is Vp. The distance between the vibration pen 3 and the vibration sensor 6 can be detected from the difference between the group velocity and the phase velocity.

First, focusing only on the envelope 421, its speed is Vg, and when a point on a certain specific waveform, for example, a peak is detected as indicated by reference numeral 43 in FIG. 4, the distance between the vibration pen 3 and the vibration sensor 6 is detected. d is its vibration transmission time t
As g, d = Vg · tg (1) This equation relates to one of the vibration sensors 6, but the same equation can indicate the distance between the other two vibration sensors 6 and the vibration pen 3.

Further, in order to determine the coordinate value with higher accuracy, processing based on the detection of the phase signal is performed. Phase waveform 4 in FIG.
If the time from the specific vibration detection point 22 such as vibration application to the zero cross point after passing the peak is tp, the distance between the vibration sensor and the vibration pen is d = n · λp + Vp · tp (2). Here, λp is the wavelength of the elastic wave, and n is an integer.

From the expressions (1) and (2), the integer n is expressed as n = [(Vg · tg−Vp · tp) / λp + 1 / N] (3). Here, N is a real number other than 0, and an appropriate value is used. For example, if N = 2, then n can be determined within ± 1/2 wavelength. The n obtained as described above can be determined.

By substituting n obtained as described above into the equation (2), the distance between the vibration pen 3 and the vibration sensor 6 can be accurately measured.

The two vibration transmission times tg and tp shown in FIG. 4 are measured by the waveform detection circuit 9 shown in FIG. The waveform detection circuit 9 is constructed as shown in FIG.

In FIG. 5, the output signal of the vibration sensor 6 is amplified by the preamplifier circuit 51 to a predetermined level. The amplified signal is input to the envelope detection circuit 52, and only the envelope of the detection signal is extracted. The timing of the peak of the extracted envelope is detected by the envelope peak detection circuit 53. The peak detection signal is a signal detection circuit 54 composed of a mono multivibrator or the like.
By the envelope delay time detection signal Tg having a predetermined waveform
Are formed and input to the arithmetic and control circuit 1.

The comparator detection circuit 58 forms a phase delay time detection signal Tp from the Tg signal and the original signal delayed by the delay time adjustment circuit 57, and the arithmetic control circuit 1
Entered in.

The circuit shown above is for one of the vibration sensors 6, and the same circuit is provided for each of the other sensors.
If the number of sensors is generalized to h, then h detection signals of envelope delay times Tg1 to h and phase delay times Tg1 to h are input to the arithmetic control circuit 1.

In the arithmetic control circuit of FIG. 3, the above Tg1 to h, Tp1 to
The h signal is input from the input port 15, and the counter value of the counter 13 is taken into the latch circuit 14 by using each timing as a trigger. As described above, since the counter 13 is started in synchronization with the driving of the transducer pen, the latch circuit 14 fetches the data indicating the delay time of each of the envelope and the phase.

When the three vibration sensors 6 are arranged at the corners of the vibration transmitting plate 8 at the positions S1 to S3 as shown in FIG. The straight line distances d1 to d3 to the position of the vibration sensor 6 can be obtained. Further, in the arithmetic control circuit 1, the coordinates of the position P of the vibrating pen 3 (x,
y) can be calculated from the Pythagorean theorem as follows.

Here, X and Y are distances along the X and Y axes between the vibration sensor 6 at the positions S2 and S3 and the sensor at the origin (position S1).

As described above, the position coordinates of the vibrating pen 3 can be detected in rear time.

In the above embodiment, the input tablet using the vibration transmission plate 8 is used by being stacked on the display 11 'by the CRT. However, the input tablet and the display do not need to be stacked in this manner, and they are separate bodies. It doesn't matter. The display may be of another display type such as a liquid crystal display.

EFFECTS OF THE INVENTION As is apparent from the above, according to the present invention, the positioning member integrally formed on the large end surface of the horn member and the vibration generating element of the spring member for pressing the vibration generating element into contact with the horn member. Since the horn member and the vibration generating element are positioned and fixed by the positioning portion fitted to the rear end surface of the horn member, the vibration generating element can be easily operated without using an adhesive that impairs vibration transmission. It is possible to provide an excellent coordinate input device that can be reliably fixed to the horn member and that can maintain accurate coordinate input accuracy for a long period of time without causing displacement of the vibration generating element and the horn member.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an explanatory view showing a configuration of an information input / output device adopting the present invention, and FIGS. 2 (A) to (C) show different structures of a vibrating pen according to the present invention. Sectional view, FIG. 3 shows the first
FIG. 4 is a block diagram showing the structure of the arithmetic control circuit of FIG. 4, FIG. 4 is a waveform diagram showing a detection waveform for explaining the distance measurement between the vibration pen and the vibration sensor, and FIG. 5 is a waveform detection circuit of FIG. FIG. 6 is a block diagram showing the configuration, and FIG. 6 is an explanatory diagram showing the arrangement of the vibration sensor. DESCRIPTION OF SYMBOLS 1 ... Arithmetic control circuit, 3 ... Vibration pen 4 ... Vibrator, 5 ... Horn part 6 ... Vibration sensor, 8 ... Vibration transmission plate 15 ... Input port, 21 ... Case 23, 26, 29A, 29B ... Convex part 24 ... Spring , 27A, 27B ... Recesses 51 ... Preamplifier 52 ... Envelope detection circuit 54, 58 ... Signal detection circuit 59 ... A / D conversion circuit

Claims (1)

[Claims] 1. The vibration transmitted to a vibration transmission member by contacting the vibration input means is detected by a vibration detection means provided on the vibration transmission member, and the vibration input means is brought into contact with the vibration transmission member. In the coordinate input device for deriving the coordinate position, the vibration input means includes: a vibration generating element that generates vibration; a horn member that transmits the vibration from the vibration generating element to the vibration transmitting member; A spring member that presses the generating element is pressed, and a positioning member that positions and fixes the horn member and the vibration generating element is integrally formed on the large end surface of the horn member that is joined to the vibration generating element. The coordinate input device is characterized in that a positioning portion is formed which is fitted to a rear end surface of the vibration generating element, which is opposed to a joint surface of the vibration generating element and the horn member.