JPS62293417A - Ultrasonic application tablet - Google Patents

Abstract

PURPOSE:To prevent a phase inversion of an input wave, which is caused by an inclination of an input pen, by forming a write plate for an ultrasonic tablet, by a multilayer structure of at least three layers or more. CONSTITUTION:In case of a write plate 3 of a composite multilayer structure, when an ultrasonic wave which has been made incident from an input pen 1 is made incident on an intermediate layer medium 3b in which the speed of sound is lower, from an input layer medium 3c in which the speed of sound is higher, an incident angle becomes small as to its angle of refraction against an inclination of the pen. It becomes equivalent to that which has made an inclination of the input pen 1 smaller. In the intermediate layer medium 3b, an area whose phase is symmetrical is enlarged. Subsequently, when the ultrasonic wave is made incident on a medium 3a in which the speed of sound is high, the ultrasonic whose phase is symmetrical is led by a sound wave receiver 4 at a higher speed than that of the ultrasonic wave whose phase is asymmetrical.

Description

[Detailed Description of the Invention] 3. Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an ultrasonic tablet for manually inputting information into a computer, etc., and is particularly suitable for highly accurate writing. The present invention relates to an ultrasonic application tablet having a writing device using a writing plate with a composite multilayer structure.

[Conventional technology]

Conventional ultrasonic application tablets generally use a single glass plate made of a single material as the writing plate, and are provided around the writing plate to allow ultrasonic waves to be written and temporarily incident from the tip of the input pen. The contact position (coordinates) of the pen tip on the writing board is determined by measuring the propagation time until it is received by the wave receiver, and from the propagation time, the speed of sound (velocity of propagation) and dimensions of the writing board, and the position of the wave receiver. This ultrasonic wave uses longitudinal waves, plate waves, surface waves, etc.

Furthermore, as a writing device using surface waves of conventional ultrasonic waves, one using a writing plate with a layered structure was published in Japanese Patent Application Laid-Open No. 1983-1989.
This is proposed in Japanese Patent No. 50830. This is a contact-type position encoder writing device that uses surface acoustic waves, and has a layered structure in which a second sheet made of a material that absorbs volumetric acoustic waves is provided below a first sheet that transmits surface waves on a writing plate. The purpose of this is to attenuate volume waves that propagate faster than surface waves and to avoid unwanted reflections causing erroneous reactions. However, no consideration is given to the structure and material of the writing board necessary to eliminate the influence of the tilt of the input pen.

[Problem that the invention seeks to solve]

” - Writing devices using the writing board made of a single material of ultrasonic tablets used as handwriting input devices in the prior art have a problem in that the orientation position changes due to the inclination of the input pen with respect to the writing board. In the case of the method of positioning by measuring the propagation time of the input pen, the waveform of the detected wave changes greatly depending on the tilt of the input pen, resulting in a total of 1III error in the propagation time, and there is a problem that accurate positioning cannot be performed. Ta.

FIGS. 6(n) to 6(d) are explanatory diagrams illustrating a situation in which the waveform of a detected wave changes due to the tilt of an input pen of a writing device of a conventional ultrasonic application tablet.

In FIGS. 6(,) to (d), when wave receivers 4A and 411 are installed at both ends of a writing board 3A made of a single material, and longitudinal ultrasonic waves are input from the midpoint P by the input pen 1. The waveforms of the waves detected by the respective wave receivers 4A and 4F3 are shown. 6th
The figure (pl) shows the detected waveform when the input pen 1 is placed perpendicular to the writing board 3A.

The first arriving wave F is detected in the same phase by both wave receivers 4A and 4B. In contrast, FIG. 6(b).

(c) and (d) are when the input pen 1 is gradually tilted toward the wave receiver 4A side with respect to the writing board 3A (tilt angle O and θx<02
<88), the first ?
The JiI arriving wave F has a slight level change but no phase change, whereas the first arriving wave F at the receiver 4A shows a phase change as well as a level change, as shown in Fig. 6(d).
), the phase will be reversed. Therefore, the transmitters 4A, 4. First arriving wave F at r3
When measuring the propagation time by focusing on 8111, for example, when measuring the propagation time by capturing the peak point of the detected wave, the phase of the first arriving wave F changes due to the tilt of the input pen 1. Since the position (time) of the peak point of the wave shifts, the measured propagation time also fluctuates, which causes a problem in the positioning error of the human-powered pen 1.

The purpose of the present invention is to reduce the waveform change of the detected wave caused by the tilt of the input pen with respect to the writing plate, and in particular to prevent phase reversal, thereby enabling highly accurate positioning using a writing plate with a composite multilayer structure. An ultrasonic application tablet with a writing device is provided.

[Means for solving problems]

The above purpose is to make the writing plate of the ultrasonic application tablet a multilayer structure with at least three layers, so that the ultrasonic waves can be propagated. A composite multilayer structure is provided in which a layer medium is provided, and an input layer medium made of a material having a faster sound velocity than the intermediate layer medium is provided on the intermediate layer medium, and the input layer is provided on the propagation layer medium side of the writing board. This is achieved by configuring a writing device by attaching a receiver of ultrasonic waves incident from an input pen on the medium.

[Effect]

The phenomenon in which the detected waveform changes when the input pen is tilted with respect to a conventional writing board made of a single material is that the phase of the SIZ component of the ultrasonic wave incident on the writing board is different from that of the input pen. The present inventor's simulation analysis revealed that this is mainly caused by the inversion caused by the inclination.

FIGS. 7(a) and 7(b) are explanatory diagrams of simulation analysis results illustrating the phase of the ultrasonic waves incident on the writing board from the input pen of the writing device of the conventional ultrasonic application tablet. Figure 7(n).

In (b), when the input pen 1 is perpendicular to the surface of the writing board (medium) 3A as shown in FIG. 7(a), the phase of the ultrasonic wave spreading within the writing board (medium) 3A is While the input pen 1 is symmetrical as shown by the arrow, when the input pen 1 is tilted as shown in FIG. 7(b), the phase of the ultrasonic wave changes as shown by the arrow in the figure. It is found that the area near the surface of the writing board (medium) 3A on the inclined side of the input pen 1 is reversed and becomes asymmetrical with respect to the input pen 1.

Furthermore, the region where the phase of the ultrasonic wave is reversed as shown in FIG. 7(b) expands as the inclination of the input pen 1 increases, and it is further confirmed that it increases approximately in proportion to the inclination angle of the input pen 1. This will become clear from detailed analysis results. Also, Figure 3 (
If you look carefully at b), even if the input pen 1 is tilted, the phase of the leading edge of the ultrasonic wave is almost symmetrical with the input pen 1 at the center in the deep region from the surface of the writing board (medium) 3A. I understand.

From these simulation analysis results, in order to reduce the change in the detected waveform due to the tilt of the input pen of the writing device, the first countermeasure is to reduce the tilt of the input pen equivalently in the area near the surface of the writing board (medium). All you have to do is make it smaller. Also, as a second measure, writing board (medium)
It has been clarified that ultrasonic waves with a symmetrical phase in a region deep from the surface of the writing plate (medium) can be guided to the wave receiver faster than ultrasonic waves with an asymmetrical phase in a region near the surface of the writing plate (medium). The present invention was made based on the elucidation of the above analysis results.

FIG. 2 is a perspective view showing an example of a basic structure of a writing device for an ultrasonic tablet according to the present invention. In Figure 2,
The writing board 3 constituting the writing device @ 2 that receives an ultrasonic wave from the input pen 1 and receives a detection wave is made of a multilayered material made of a multilayer medium of at least 3M or more, and the ultrasonic wave is propagated and guided to the wave receiver. An intermediate layer medium 3 made of a material having a lower sound velocity (propagation speed) than the propagation layer medium 3a is disposed on the layer medium 3a.
b, and further provided on the intermediate layer medium 3b is an input layer medium 3c made of a material having a faster sound velocity than the intermediate layer medium 3b. ) wave receivers 4 (4a to 4d) are attached.

According to the writing device 2 using the writing board 3 having such a composite multilayer structure, first, the ultrasonic waves incident from the input pen 1 are transmitted from the input layer medium 3c, which has a faster sound speed, to the intermediate layer medium 3b, which has a slower sound speed. When a sound wave is refracted, even if the angle of incidence is large, the angle of refraction becomes smaller, which is equivalent to making the inclination angle of the input pen 1 smaller and making the ultrasonic wave incident on the intermediate layer medium 3b. Therefore, within the intermediate layer medium 3b, the region of ultrasonic waves whose phase is asymmetrical with respect to the input pen is reduced, and the region of ultrasonic waves whose phase is symmetrical is expanded. Next, the ultrasonic wave whose phase is more symmetrical is transferred from the intermediate layer medium 3b where the sound speed is slower to the propagation layer medium 3a where the sound speed is faster.
As a result, the ultrasonic waves with more symmetrical phase reach the receiver 4 (4a to 4) faster than the ultrasonic waves with asymmetrical phase.
d). Due to the above two effects, the influence of the tilt of the input pen 1 on the writing plate 3 is reduced, and the wave receiver 4
Since changes in the detected waveform and especially inversion of the phase due to (4a to 4d) can be prevented, measurement errors in the propagation time of ultrasonic waves can be eliminated and positioning can be performed with high accuracy.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 to 5.

FIG. 1 is an overall configuration diagram showing an embodiment of an ultrasonic application tablet using longitudinal waves according to the present invention.

In FIG. 1, 1 is an input pen, 2 is a writing device, and these constitute a writing section. ;3 is a writing board, 4
(48 to 4d) are wave receiving elements installed at a part of each corner, and these constitute the writing device 2. input pen 1
consists of a wave transmitter 1a, a pen tip 1b, and a grip 1c. The writing plate 3 includes a propagation layer medium 38 that guides ultrasonic waves to the wave receivers 43 to 4 d according to the present invention, and a propagation layer medium 38 provided on the propagation layer medium 3a that has a speed of sound (longitudinal wave propagation velocity) higher than that of the propagation layer medium 3a. It has a composite multilayer structure including at least three layers of a slow intermediate layer medium 3b and an input layer medium 3c provided on the intermediate layer medium 3b and having a faster sound speed than the intermediate layer medium 3b, and has a composite multilayer structure of at least three layers.
4d is attached to the side of the transfer ITtIFPJ medium 3a. 5 is a pulse excitation circuit that applies a pulse voltage to the input pen 1; 6 is a waveform shaping circuit that shapes the detected waves of the wave receiving elements 48 to 4d; 7 is a waveform shaping circuit that applies an output signal of the waveform shaping circuit 6 from the input pen 1 to the wave receiving element 48; A time counting circuit for counting the propagation time of the ultrasonic waves up to 4d; 8 a coordinate calculation circuit for calculating the position (coordinates) of the input pen 1 based on the output of the time counting circuit 7; 9 provided directly below the writing board 3; coordinate calculation circuit 8
This is a display device that displays the position (coordinate) W determination result.

With the above configuration, a pulse voltage is applied from the pulse excitation circuit 5 to the wave transmitter 1a of the input pen 1, and the pen tip 1b of the input pen 1
Longitudinal ultrasound waves are emitted. As a result, the longitudinal ultrasonic waves incident on the writing plate 3 having a composite multilayer structure consisting of the propagation layer medium 3a, intermediate medium 3b, and input layer medium 3C are refracted when entering the intermediate layer medium 3b from the input layer medium 3C. As the angle becomes smaller than the incident angle, the ultrasonic wave with good phase symmetry enters the propagation layer medium 3a from the intermediate layer medium 3b and propagates to the receivers 4Q to 4d at a faster sound speed, causing the propagation. Ultrasonic waves with good symmetry, which reduces the influence of the tilt of the input pen 1, are detected by each of the wave receivers 48 to 4d attached to the side of the MII and the body 3a. This wave receiver 48~4d
The detected wave is input to a waveform shaping circuit 6, and the output waveform-shaped by this waveform shaping circuit 6 is inputted to a time counting circuit 7.
Pen tip 1b of the input pen 1 based on the output pulse of
and the ultrasonic incidence point at the contact position of the writing plate 3 and each wave receiver 4R.
Ultrasonic propagation time is measured until ~4d. The output of this time counting circuit 7 is input to a coordinate calculation circuit 8, and each receiver 4
After calculating the position (coordinates) of the ultrasonic incident point of the input pen 1 from the propagation times from a to 4d, the positioning result is displayed directly below the writing board 3'! It is displayed in A position 9.

In this way, according to this embodiment, since the writing plate 3 of the writing device 2 has the above-described composite multilayer structure, changes in the detected waveforms of the wave receivers 4a to 4d are reduced even when the input pen 1 is tilted. In particular, phase reversal can be prevented,
Therefore, highly accurate positioning is possible. If a transparent material is used for the writing board 3, these positioning results can be directly displayed on the display device i''?9 directly below.

FIGS. 3(a) and 3()+) are explanatory diagrams showing the material structure of each layer medium used in one embodiment of the writing plate 3 of FIG. 1 (FIG. 2) and analysis results obtained by simulation thereof. In Part 3!4 (a), the propagation layer medium 3a and the input layer medium 3c constituting the #embedded board 3 are made of the same glass material, which has a faster sound velocity (longitudinal wave propagation velocity), and the intermediate layer medium 3b is It uses ethylene vinyl acetate, a material with a slower speed of sound.

In FIG. 3())), the simulation analysis results of the writing board 3 having a composite multilayer structure with the material composition of each layer medium shown in FIG. Although the phase of the ultrasonic wave indicated by the arrow in the figure is reversed in the region on the inclined side of the pen 1, the influence of the inclination of the input pen 1 is reduced when it enters the intermediate layer medium 3b, and The phase of the ultrasonic wave indicated by the arrow is almost symmetrical with respect to the input pen 1, and the effect of the writing plate 3 having a single-condensed multilayer structure is confirmed by simulation.

According to the writing board 3 of this embodiment, the propagation layer medium 3a and the input layer medium 3C are made of glass, the input layer medium: 3 (z can be easily configured as an adhesive layer of ethylene vinyl acetate, and each layer medium is made of a transparent material. Therefore, as shown in FIG. 1, by joining the display surface of a display device 9 such as a liquid crystal display or CRT directly below the writing device 2 using the book writing board 3, the input surface and the display surface can be integrated. It is possible to realize an ultrasonic application tablet with a
Figure 3(a) shows transparent materials with different longitudinal wave propagation speeds.
There are many options other than those shown, and various combinations are possible. Next, of course, opaque materials may be used for each layer medium, and since there are many opaque materials with different sound velocities, various combinations thereof are possible.

FIGS. 4(a) and 4(b) are explanatory diagrams showing the material structure of each layer medium used in another embodiment of the writing plate 3 shown in FIG. 2, and the analysis results obtained by simulation thereof. Figure 4(a)
In this case, the propagation layer medium 3a constituting the writing board 3 is made of glass, which is a material with a faster sound speed, the intermediate layer medium 3b is an adhesive layer of ethylene vinyl acetate, which is a material with a slower sound speed, and the input layer medium 3C is an intermediate layer with a faster sound speed. Polycarbonate is used, which is a material that is faster than the medium 3b and slower than the propagation layer medium 3a. In FIG. 4, in the simulation analysis results of the writing board 3 having a composite multilayer structure with the material composition of each layer medium shown in FIG. Since the propagation layer medium 3a becomes faster, the ultrasonic wave propagates fastest in the propagation layer medium 3a, as shown by the arrow in the figure indicating the phase of the ultrasonic wave. The ultrasonic waves in the intermediate layer medium 3b and the input layer medium 3c, which propagate slowly, do not interfere with and affect the leading portion of the ultrasonic waves propagating in the propagation layer medium 3a. Therefore, according to this embodiment, the detected waveform of the [th] arrival wave of the wave receivers 48 to 4d attached to the side of the propagation layer medium 3a becomes more stable, and more accurate positioning becomes possible. Further, in embodiments of the writing plate 3 in which a viscoelastic material with particularly high attenuation of transverse waves, such as a Got1 sheet, etc. is used as the intermediate layer medium 3b, or a liquid material that hardly transmits transverse waves is used, the composite material according to the present invention may be used. The effect of multi-layered structure becomes greater.

Figure 5 shows the writing board 3 (writing device 2) in Figure 1 (Figure 2).
) is a sectional view showing the material structure of each layer medium of still another example. In FIG. 5, a liquid material that hardly transmits ultrasonic transverse waves is used as an intermediate layer medium 3b between a propagation layer medium 3a and an input layer medium 3c constituting the writing plate 3,
The periphery thereof is sealed with a sealing material 10. According to this embodiment, the effect of the composite multilayer structure of the writing plate 3 according to the present invention is further enhanced. Further, in this embodiment, it is also possible to use a transparent material for the input layer medium 3c, and to use liquid crystal as the liquid material for the intermediate layer medium 3b, so that display can be performed on this liquid crystal. In this case, input pen 1
Since the incident position of the pen tip 1°b and the display position are extremely close to each other, it is possible to realize an integrated input/display ultrasonic application tablet with little parallax.

In each of the above-mentioned embodiments, the input layer medium 3c of the writing board 3 has a composite multilayer structure of three or more layers with an extremely thin surface sheet provided at H, and the surface sheet is designed to prevent the input pen 1 from slipping. Furthermore, in the above embodiment, the intermediate layer medium 3b may be an adhesive layer. It may be made of a non-adhesive material.

〔Effect of the invention〕

According to the present invention, it is possible to reduce the change in the detected waveform caused by the tilt of the input pen in the ultrasonic application tablet 1-, and in particular to prevent phase inversion, making it possible to perform highly accurate positioning. Since there is no need to correct the detected waveform or phase inversion using , it can be easily and inexpensively created.

[Brief explanation of drawings]

FIG. 1 is an overall configuration diagram showing one embodiment of an ultrasonic application tablet according to the present invention, FIG. 2 is a basic configuration diagram of a writing device, and FIGS. 3(a) and (b) are an implementation of a writing board. Example material composition and explanatory diagram of simulation results, Part 4
Figures (a) and (b) are illustrations of the material composition of another example of the writing board and explanatory diagrams of simulation results, Figure 5 is a sectional view of the material composition of yet another example of the writing plate, and Figure 6 Figures (a) to (d) are explanatory diagrams of the inclination of each input pen and detected waveforms of a conventional writing device, and Figure 7 (a). (b) is also an explanatory diagram of the simulation results when each input pen is vertical and tilted. DESCRIPTION OF SYMBOLS 1... Input pen, 2... Writing device, 3... Writing board; 38... Propagation layer medium, 3b... Intermediate layer medium, 3c... Input layer medium, 4a to 4d.・Receiver wave element, 5
... Pulse excitation circuit, 6... Waveform shaping circuit, 7...
- Time counting circuit, 8... Coordinate calculation circuit, 9... Display device, 10... Sealing material.

Claims (1)

[Claims] 1. The input ultrasonic wave emitted from the input pen tip is propagated through the writing plate, the propagated ultrasonic wave is detected by a wave receiver, and the input pen is activated based on the detection signal. In the ultrasonic application tablet for locating the coordinate position on the writing plate, the writing plate includes a propagation layer medium for propagating ultrasonic waves, and a material having a lower sound speed than the propagation layer medium provided on the propagation layer medium. and an input layer medium made of a material having a faster sound velocity than the intermediate layer medium provided on the intermediate layer medium. An ultrasonic application tablet characterized by being equipped with an ultrasonic wave receiver. 2. The ultrasonic application tablet according to claim 1, wherein the input layer medium is made of a material having a lower sound velocity than the propagation layer medium. 3. The ultrasonic application tablet according to claim 1, wherein the intermediate layer medium is made of a viscoelastic material with high attenuation of transverse waves. 4. The ultrasonic application tablet according to claim 1, wherein the intermediate layer medium is made of a liquid material that hardly transmits transverse waves. 5. The ultrasonic application tablet according to claim 4, wherein the intermediate layer medium is made of a liquid crystal material that can also be used for display purposes.