JPH0668716B2 - Ultrasonic application tablet - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an ultrasonic application tablet for manually inputting information in a computer or the like, and particularly to a writing plate having a composite multilayer structure suitable for highly accurate writing. The present invention relates to an ultrasonic application tablet having a writing device using.

[Conventional technology]

In the conventional ultrasonic application tablet, a single glass plate made of a single material is generally used as a writing plate, and ultrasonic waves are made incident on the writing plate from the pen tip of an input pen to provide the writing plate around the writing plate. The propagation time until it is received by the received wave receiver is measured, and the contact position (coordinates) of the pen tip on the writing board is calculated from the propagation time, the sound velocity (propagation speed) and size of the writing board, and the position of the receiving board. ), And longitudinal waves, plate waves, surface waves, etc. are used as the ultrasonic waves.

As a conventional writing device using surface waves among ultrasonic waves, one using a writing plate having a layered structure is disclosed in Japanese Patent Laid-Open No. 50-50.
No. 830 is proposed. This is a writing device for a contact type position encoder using surface acoustic waves, which has a layered structure in which a second sheet made of a material that absorbs volume acoustic waves is provided under a first sheet that transmits the surface waves of a writing plate. With the purpose of attenuating volume waves propagating faster than surface waves and avoiding unwanted reflections causing false reactions. However, no consideration is given to the structure and material of the writing plate necessary to eliminate the influence of the tilt of the input pen.

[Problems to be solved by the invention]

In the writing device using the writing plate made of a single material of the ultrasonic application tablet used as the above-mentioned conventional handwriting input device, there is a problem that the orientation position changes due to the inclination of the input pen with respect to the writing plate. In the case of the method that measures the propagation time of the position to measure the position, the waveform of the detected wave changes greatly due to the inclination of the input pen, which causes a measurement error of the propagation time, and there is a problem that the position cannot be accurately measured. Atsuta

FIGS. 6 (a) to 6 (d) are explanatory views illustrating the situation in which the waveform of the detected wave changes due to the inclination of the input pen of the writing device of the conventional ultrasonic application tablet. FIG. 6 (a)-
In (d), the wave receivers 4A and 4B are installed at both ends of the writing plate 3A made of a single material, and the wave receivers 4A and 4A when the longitudinal ultrasonic waves are incident from the intermediate point P by the input pen 1.
The waveform of the detection wave by B is shown. FIG. 6 (a) shows a detection waveform when the input pen 1 is placed vertically with respect to the writing plate 3A.
The first arrival wave F is detected in phase by both wave receivers 4A and 4B. On the other hand, FIG. 6 (b), (c), (d)
Is a detected waveform when the input pen 1 is gradually inclined to the wave receiver 4A side with respect to the writing plate 3A (tilt angle O <θ ₁ <θ ₂ <θ ₃ ), and the first arrival wave F at the wave receiver 4B is shown. Shows a slight level change but no phase change, whereas the first arriving wave F in the wave receiver 4A shows a phase change with a level change and has a large inclination in FIG. 6 (d). The phase is reversed. Therefore, the longitudinal ultrasonic wave receiver 4 incident from the input pen 1 on the writing plate 3A made of a single material.
When measuring the propagation time by paying attention to the first arrival wave F in A and 4B, for example, when measuring the propagation time by capturing the peak point of the detected wave, the inclination of the input pen 1 causes the first arrival wave to arrive. Since the position (time) of the peak point of the detected wave shifts due to the phase change of F, the measured propagation time also fluctuates, which causes a problem of positioning error of the input pen 1.

An object of the present invention is to provide a writing plate having a composite multi-layer structure that enables highly accurate position localization by reducing the waveform change of the detection wave caused by the inclination of the input pen with respect to the writing plate and preventing phase inversion in particular. An ultrasonic application tablet having the writing device used is provided.

[Means for solving problems]

The above-mentioned object is that the writing plate of the ultrasonic application tablet has a multi-layered structure of at least three layers or more, and the intermediate layer is made of a material having a slower sound velocity (propagation speed) than the propagation layer medium on the propagation layer medium for propagating the ultrasonic waves. A layered medium is provided, and an input layer medium made of a material having a higher sound velocity than that of the intermediate layer medium is further provided on the intermediate layer medium to form a composite multilayer structure, and the input layer is provided on the propagation layer medium side of the writing plate. This is achieved by constructing a writing device by attaching an ultrasonic wave receiver incident from an input pen on the medium.

[Action]

The phenomenon that the detected waveform changes when the input pen is tilted with respect to the conventional writing plate made of a single material is that the phase of the component of the ultrasonic waves incident on the writing plate parallel to the writing plate is the inclination of the input pen. It was clarified by the analysis by the simulation of the present inventor that the phenomenon mainly occurs due to the inversion.

FIGS. 7 (a) and 7 (b) are explanatory diagrams of the simulation analysis result illustrating the phase of the ultrasonic waves incident on the writing plate from the input pen of the writing device of the conventional ultrasonic application tablet. 7 (a) and 7 (b), FIG. 7 (a)
When the input pen 1 is perpendicular to the surface of the writing plate (medium) 3A as shown in FIG. 3, the phase of the ultrasonic wave expanding in the writing plate (medium) 3A is centered on the input pen 1 as shown by the arrow in the figure. On the other hand, when the input pen 1 is tilted as shown in FIG. 7 (b), the phase of the ultrasonic wave is the writing plate on the tilt side of the input pen 1 as shown by the arrow in the drawing. Medium) 3A
It is found that the image is inverted in the area near the surface of the and becomes asymmetrical about the input pen 1. Furthermore, the region in which the phase of the ultrasonic wave is inverted as shown in FIG. 7B expands as the inclination of the input pen 1 increases, and it further increases in proportion to the inclination angle of the input pen 1. It will be known from detailed analysis results. Also, paying attention to FIG. 3 (b), even if the input pen 1 is inclined, in the region deep from the surface of the writing plate (medium) 3A, the phase of the leading portion of the ultrasonic wave is almost centered on the input pen 1. You can see that they are symmetrical.

From such a simulation analysis result, in order to reduce the change in the detected waveform due to the inclination of the input pen of the writing device, as a first countermeasure, the inclination of the input pen is equivalent in the area near the surface of the writing plate (medium). It should be small. As a second measure, a writing board (medium)
It is clarified that ultrasonic waves having a phase symmetry in a deeper region from the surface of the surface should be guided to the receiver faster than ultrasonic waves having a phase asymmetry in the region near the surface of the writing plate (medium). The present invention has been made with a focus on elucidation of the above analysis results.

FIG. 2 is a perspective view showing an example of the basic configuration of a writing device for an ultrasonic application tablet according to the present invention. In FIG.
The writing plate 3 that constitutes the writing device 2 that receives the ultrasonic wave from the input pen 1 to generate the detection wave has a multi-layered structure including a multi-layered medium having at least three layers, and propagates the ultrasonic wave to the wave receiver. On the medium 3a, the intermediate layer medium 3 made of a material whose sound velocity (propagation velocity) is slower than that of the propagation layer medium 3a.
b, and an input layer medium 3c made of a material having a higher sonic velocity than the intermediate layer medium 3b is further provided on the intermediate layer medium 3b to form a composite multilayer structure, and the side (4 corners) of the propagation layer medium 3a. The wave receiver 4 (4a to 4d) is attached.

According to the writing device 2 using the writing plate 3 having such a composite multi-layer structure, the ultrasonic wave incident from the input pen 1 is first transmitted from the input layer medium 3c having a higher sound speed to the intermediate layer medium 3b having a lower sound speed. As the sound wave is refracted, even if the incident angle is large, the refraction angle becomes smaller. As a result, it 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. In the intermediate layer medium 3b, a region of ultrasonic waves having an asymmetric phase with respect to the input pen 1 is reduced, and a region of ultrasonic waves having a symmetrical phase is enlarged. Next, the ultrasonic wave having a more symmetric phase enters the propagation layer medium 3a having a higher sound speed from the intermediate-layer medium 3b having a slower sound speed and propagates. As a result, the ultrasonic wave having a more symmetric phase has an asymmetric phase. Receiving element 4 (4a-4
Guided to d). Due to the above two effects, the influence of the inclination of the input pen 1 on the writing plate 3 is reduced, and
Since it is possible to prevent changes in the detected waveform due to (4a to 4d) and especially phase inversion, it is possible to eliminate the measurement error of the propagation time of the ultrasonic wave and perform the position localization with high accuracy.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS.

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 unit. Reference numeral 3 is a writing plate, and 4 (4a to 4d) are wave receivers installed at respective corners thereof, which constitute the writing device 2. The input pen 1 includes a wave transmitter 1a, a pen tip 1b, and a grip 1c. The writing plate 3 is a propagation layer medium 3a that guides ultrasonic waves to the wave receivers 4a to 4d according to the present invention.
An intermediate layer medium 3b provided on the propagation layer medium 3a and having a sound velocity (longitudinal wave propagation velocity) slower than that of the propagation layer medium 3a, and an intermediate layer medium 3b provided on the intermediate layer medium 3b. Also has a composite multi-layer structure of at least three layers of the input layer medium 3c having a high sound velocity, and the wave receivers 4a to 4d are the propagation layer medium 3
It is attached to the side of a. Reference numeral 5 is a pulse excitation circuit for applying a pulse voltage to the input pen 1, 6 is a waveform shaping circuit for shaping the detection waves of the wave receivers 4a to 4d, and 7 is a waveform shaping circuit 6
A time counting circuit for counting the propagation time of the ultrasonic wave from the input pen 1 to the wave receivers 4a to 4d in accordance with the output signal of 8 and a coordinate calculation 8 for performing the position (coordinate) orientation calculation of the input pen 1 by the output of the time counting circuit 7. A circuit 9 is a display device for displaying a position (coordinate) orientation result by the coordinate operation circuit 8 provided directly below the writing plate 3.

With the above configuration, a pulse voltage is applied from the pulse excitation circuit 5 to the transmitter 1a of the input pen 1, and the pen tip 1b of the input pen 1 is applied.
More longitudinal ultrasonic waves are emitted. As a result, the longitudinal ultrasonic waves incident on the writing plate 3 having the composite multilayer structure including the propagation layer medium 3a, the intermediate medium 3b, and the input layer medium 3c are refracted when entering the intermediate layer medium 3b from the input layer medium 3c. While the angle becomes smaller than the incident angle, ultrasonic waves having good phase symmetry from the intermediate layer medium 3b enter the propagation layer medium 3a and propagate to the receivers 4a to 4d at a higher speed of sound. Each wave receiver 4a attached to the side of the layer medium 3a
By 4d, an ultrasonic wave with good symmetry in which the influence of the inclination of the input pen 1 is reduced is detected. The detected waves from the wave receivers 4a to 4d are input to the waveform shaping circuit 6, the output waveform-shaped by the waveform shaping circuit 6 is input to the time counting circuit 7, and the output of the pulse excitation circuit 5 is output by the time counting circuit 7. An ultrasonic wave incident point at a contact position between the pen tip 1b of the input pen 1 and the writing plate 3 and each of the wave receivers 4a to 4 on the basis of a pulse.
The ultrasonic propagation time is measured up to d. The output of the time counting circuit 7 is input to the coordinate calculating circuit 8 and the respective wave receivers 4a to 4a.
After the position (coordinates) orientation calculation of the ultrasonic wave incident point of the input pen 1 is performed from the propagation time up to 4d, the position orientation result is displayed on the display device 9 directly below the writing plate 3.

In this way, according to the present embodiment, the writing plate 3 of the writing device 2 has the above-described composite multi-layer structure, so that even when the input pen 1 is tilted, changes in the detected waveforms of the wave receivers 4a to 4d are reduced. It is possible to prevent the phase reversal,
Therefore, highly accurate position location can be performed. Such a position locating result can be directly displayed on the display device 9 directly below if a transparent material is used for the writing plate 3.

FIGS. 3 (a) and 3 (b) show the writing plate 3 of FIG. 1 (FIG. 2).
FIG. 6 is an explanatory diagram showing a material configuration of each layer medium used in one example and an analysis result by the simulation. Third
In FIG. 3A, the propagation layer medium 3 that constitutes the writing plate 3
The a and the input layer medium 3c are made of glass of the same material having a faster sound velocity (longitudinal wave propagation velocity), and the intermediate layer medium 3b is made of ethylene vinyl acetate, which is a material having a slower sound velocity. In FIG. 3 (b), the simulation analysis result of the writing plate 3 having the composite multi-layer structure by the material composition of each layer medium in FIG. 3 (a) shows the input pen in the input layer medium 3 c incident from the input pen 1 according to the simulation analysis result. Although the phase of the ultrasonic wave indicated by the arrow in the figure is inverted in the region on the inclined side of 1, the intermediate layer medium 3b
When it enters inside, the influence of the inclination of the input pen 1 is reduced, and further, in the propagation layer medium 3a, the phase of the ultrasonic wave indicated by the arrow is substantially symmetrical with the input pen 1 as the center. The effect of the plate 3 is confirmed by the simulation.

According to the writing plate 3 of this embodiment, the propagation layer medium 3a and the input layer medium 3c are made of glass, the input layer medium 3c can be easily constructed as an adhesive layer of ethylene vinyl acetate, and each layer medium is made of a transparent material. As shown in FIG. 1, by joining a display surface of a display device 9 such as a liquid crystal display device or a CRT directly below a writing device 2 using the writing plate 3, an input surface and a display surface are integrated. Sonic application tablet can be realized. There are many transparent materials having different sound velocities (longitudinal wave propagation velocities) of the layered media of the writing plate 3 other than those shown in FIG. 3A, and various combinations are possible. Next, of course, an opaque material may be used for each layer medium, and there are many opaque materials having different sound velocities, and various combinations thereof are possible.

FIGS. 4 (a) and 4 (b) are explanatory views showing the material composition of each layer medium used in another embodiment of the writing plate 3 in FIG. 2 and the analysis result by the simulation. Figure 4 (a)
In FIG. 3, the propagation layer medium 3a constituting the writing plate 3 is glass of a material having a higher sound velocity, the intermediate layer medium 3b is an adhesive layer of ethylene vinyl acetate which is a material of a slower sound velocity, and the input layer medium 3c is an intermediate layer having a sound velocity. Polycarbonate, which is a material faster than the medium 3b and slower than the propagation layer medium 3a, is used. In FIG. 4, in the simulation analysis result of the writing plate 3 having the composite multilayer structure based on the material configuration of each layer medium in FIG. 4A, the sound velocity of the material of each layer medium is the intermediate layer medium 3b, the input layer medium 3c, and the propagation. Since the layer medium 3a becomes faster in order, the ultrasonic wave propagates fastest in the propagation layer medium 3a as indicated by the arrow in the figure, and as a result, the ultrasonic wave propagates faster than the propagation layer medium 3a. The ultrasonic waves in the intermediate layer medium 3b and the input layer medium 3c whose velocity is slow are propagated by the propagation layer medium 3
There is no influence by interfering with the leading portion of the ultrasonic wave propagating in a. Therefore, according to the present embodiment, the detected waveform of the first arrival wave of the wave receivers 4a to 4d attached to the side of the propagation layer medium 3a becomes more stable, and more accurate position location becomes possible. . Further, as the intermediate layer medium 3b, a viscoelastic material having a large attenuation of transverse waves, for example, a rubber sheet or the like is used. Further, in the embodiment of the writing plate 3 using a liquid material that hardly transmits transverse waves, the composite according to the present invention is used. The effect of the multilayer structure is increased.

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

In each of the above-described embodiments, the writing pen 3 has a composite multi-layer structure of three layers or more in which an ultrathin surface sheet is provided on the input layer medium 3c so that the input pen 1 does not easily slip. It is also possible to mix friction materials, and the surface sheet may serve as a surface protective layer of the input layer medium 3c. Further, in the above-mentioned embodiment, the intermediate layer medium 3b may be made of an adhesive layer having a material structure having no adhesive property.

〔The invention's effect〕

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 and prevent the phase inversion in particular, so that it is possible to perform the highly accurate position location and use the special additional circuit. Since it is not necessary to correct the detected waveform and phase inversion by using the method, it can be easily and inexpensively created.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing an 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 3 (b) are one implementation of a writing plate. The material composition of the example and an explanatory view of the result of simulation, FIGS. 4 (a) and 4 (b) are the same as the material composition of another embodiment of the writing plate, and an explanatory view of the result of the simulation, and FIG. Sectional drawing of the material constitution of further another Example, 6th
FIGS. 7A to 7D are explanatory views of the inclination and detection waveform of each input pen of the conventional writing device, and FIGS. 7A and 7B are the same as the vertical direction of each input pen, and the simulation simulation when inclined. It is explanatory drawing of a result. 1 ... input pen, 2 ... writing device, 3 ... writing board,
3a ... Propagation layer medium, 3b ... Intermediate layer medium, 3c ... Input layer medium, 4a-4d ... Receiving element, 5 ... Pulse excitation circuit, 6 ... Waveform shaping circuit, 7 ... Time counting circuit, 8 ……
Coordinate calculation circuit, 9 ... Display device, 10 ... Sealing material.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Shigeru Inose 800 Tomioka, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi Co., Ltd. Tochigi factory (72) Inventor Hideo Fukuhashi 800 Tomioka, Ohira-cho, Shimotsuga-gun, Tochigi Hitachi, Ltd. Tochigi Plant (56) Reference JP 60-230230 (JP, A) JP 60-132228 (JP, A) JP 61-281324 (JP, A) JP 61-168031 (JP, A)

Claims (5)

[Claims] 1. An input pen having an ultrasonic wave transmitter incorporated therein is brought into contact with a writing plate, and ultrasonic waves propagated from the input pen into the writing plate are attached to a plurality of positions on a side portion of the writing plate. In an ultrasonic application tablet which is received by a sound wave receiver and determines the contact position on the surface of the writing plate of the input pen from the received signal of each ultrasonic wave receiver, the writing plate is an input layer medium with which the input pen contacts. A plate, an ultrasonic wave propagation layer medium plate to which each of the ultrasonic wave receivers is attached to the side, and an ultrasonic wave propagation speed slower than both of which is interposed between the input layer medium plate and the ultrasonic wave propagation layer medium plate. The ultrasonic wave receiver has at least a three-layered structure including an intermediate layer medium made of a material, and each of the ultrasonic wave receivers is input from an input pen to an input layer medium plate and propagates through the intermediate layer medium in the ultrasonic wave propagation medium. Configuration for receiving sound waves Ultrasonic application tablets, characterized in that the. 2. The ultrasonic application tablet according to claim 1, wherein the input layer medium plate is made of a material slower than the ultrasonic wave propagation velocity of the ultrasonic wave propagation layer medium plate. 3. The ultrasonic application tablet according to claim 1, wherein the intermediate layer medium is made of a viscoelastic material having a large attenuation of transverse waves. 4. The ultrasonic application tablet according to claim 1, wherein the intermediate layer medium is a liquid material. 5. The ultrasonic application tablet according to claim 4, wherein the intermediate layer medium is made of a liquid crystal material commonly used for display.