JP2002182842A - Ultrasonic wave touch panel system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a contact position with high sensitivity when a surface acoustic wave comes into contact with a propagated non-piezoelectric plate. SOLUTION: Fifteen first surface acoustic wave propagation paths are formed between interdigital electrodes Tx1 to Tx5 for input and electrode groups Gx1 to Gx5 on the top edge surface of the non-piezoelectric plate 1 by applying an input electric signal to two adjacent interdigital electrodes for input at the same time. Similarly, fifteen second surface acoustic wave propagation paths are formed between interdigital electrodes Ty1 to Ty5 for input and electrode groups Gy1 to Gy5. When the point of intersection between a first surface acoustic wave propagation path and a second surface acoustic wave propagation path is touched, first and second delay electric signals appear at one terminal among terminals Ux1 to Ux3 and at one terminal among terminals Uy1 to Uy3 respectively. The contact position can be discriminated from the phases of the first and second delay electric signals.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic touch panel system in which when a non-piezoelectric plate on which a surface acoustic wave is propagated comes into contact, the contact position is determined.

[0002]

2. Description of the Related Art A conventional touch panel generally includes a wedge type transducer and a piezoelectric thin film transducer. The wedge-type transducer has a function of indirectly causing an elastic vibration on a non-piezoelectric plate, and the piezoelectric thin-film transducer has a function of directly causing an elastic vibration on a non-piezoelectric plate. In any case, such a conventional touch panel is based on the fact that the ultrasonic wave on the non-piezoelectric plate disappears due to the contact on the non-piezoelectric plate and the output electric signal is not detected. The contact position is determined from the arrangement of the output transducer that is no longer detected. Therefore, the conventional touch panel needs to always drive all the input transducers, so that not only has a problem in driving voltage and power consumption, but also requires a complicated circuit configuration.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide an ultrasonic touch panel system capable of detecting a contact position with high sensitivity by detecting a delayed electric signal appearing when a non-piezoelectric plate is touched. . A further object of the present invention is to provide an ultrasonic touch panel system that is low-voltage and low-power-consumption driven, has a simple circuit configuration, has a high response speed to contact, can be mass-produced, is small, lightweight, and has excellent durability. To provide.

[0004]

According to the first aspect of the present invention, there is provided an ultrasonic touch panel system comprising: a non-piezoelectric plate;
An ultrasonic touch panel system comprising an ultrasonic wave propagation means, first and second signal processing means, and a signal analyzer, wherein the first ultrasonic wave propagation means has at least two interdigital transducers Txi (i = 1 , 2,..., M), at least two electrode groups Gxi (i = 1, 2,..., M), first and second piezoelectric substrates, and at least two terminals Uxj (j = 1, 2,. , n), and one of two adjacent electrodes of the electrode group Gxi is composed of at least two output IDTs (x = 1, 2,..., n), and the other is at least two output IDTs. Electrode Rx
bj (j = 1, 2,..., n), and the output interdigital transducer R
xaj and Rxbj have opposite electrode finger directions, and the terminals Uxj are respectively connected to the output IDTs Rxaj and connected to the output IDTs Rxbj, respectively, and the second The sound wave propagation means includes at least two interdigital transducers Tyi (i = 1, 2,..., M), at least two electrode groups Gyi (i = 1, 2,. A piezoelectric substrate and at least two terminals Uyj (j = 1, 2,
, N), and two adjacent ones of the electrode group Gyi have at least two IDT electrodes Ryaj (j = 1, 2,
, N) and the other comprises at least two output interdigital transducers Rybj (j = 1, 2,..., N), and the output interdigital transducers Ryaj and Rybj are arranged such that the directions of the electrode fingers are mutually different. On the contrary, the terminal Uyj is connected to the output IDT Ryaj.
And each is connected to the output IDT Rybj, and the input IDT Tx
i, the electrode group Gxi, the input IDT Tyi, and the electrode group Gyi are the first, second,
The first, second, third, and fourth piezoelectric substrates are provided at third and fourth edges, respectively, and the first, second, third, and fourth piezoelectric substrates include the input IDT Txi, the electrode group Gxi, the input IDT Tyi, and the input IDT. The first group is provided on each of the electrode groups Gyi.
The signal processing means includes a fifth piezoelectric substrate, first, second, and third pairs of electrodes provided on the fifth piezoelectric substrate, and a first synchronization pulse generator. The second signal processing means includes a sixth piezoelectric substrate. The signal analyzer comprises a substrate, fourth, fifth, and sixth pairs of electrodes provided on the sixth piezoelectric substrate, and a second synchronization pulse generator, wherein the signal analyzer is connected to the first and second signal processing means. , The first two of the interdigital transducers Txi
When an input electric signal is applied, a first surface acoustic wave is excited on the first piezoelectric substrate, and the first surface acoustic wave is transmitted to the second piezoelectric substrate via the upper end surface of the non-piezoelectric plate. Propagated, said output interdigital transducers Rxaj and Rxbj
Is converted into a first output electric signal, and a second input electric signal is applied to two adjacent input interdigital transducers Tyi, whereby a second surface acoustic wave is excited on the third piezoelectric substrate. The second surface acoustic wave is propagated to the fourth piezoelectric substrate via the upper end surface of the non-piezoelectric plate,
Each of the output interdigital transducers Ryaj and Rybj is converted into a second output electric signal, and appears at one of the terminals Uxj and one of the terminals Uyj by contacting the upper end surface of the non-piezoelectric plate, respectively. The first and second delayed electric signals are directly detected by the signal analyzer, and detected by the signal analyzer after passing through the first and second signal processing means, and the upper end surface of the non-piezoelectric plate Is determined by the phases of the first and second delayed electric signals detected by the signal analyzer.

In an ultrasonic touch panel system according to a second aspect, the first, second, third and fourth piezoelectric substrates are integrated to form one window frame structure.

According to a third aspect of the present invention, there is provided the ultrasonic touch panel system according to the first, second, third, fourth, fifth and sixth aspects.
The piezoelectric substrate is made of piezoelectric ceramic, and the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction.

According to a fourth aspect of the present invention, the non-piezoelectric plate is made of a transparent material.

The ultrasonic touch panel system according to claim 5, wherein the thickness of the first, second, third and fourth piezoelectric substrates is smaller than the electrode cycle length of the input interdigital transducers Txi and Tyi, The thickness of the non-piezoelectric plate is greater than three times the electrode cycle length.

According to a sixth aspect of the present invention, in the ultrasonic touch panel system, the phase velocity of the surface acoustic wave propagating to the non-piezoelectric plate itself is transmitted to the first, second, third and fourth piezoelectric substrates themselves. Faster than the phase velocity of the waves.

An ultrasonic touch panel system according to a seventh aspect of the present invention includes first and second switches connected to the input interdigital transducers Txi and Tyi, respectively.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic touch panel system according to the present invention comprises a non-piezoelectric plate, first and second ultrasonic wave propagation means,
It has a simple structure consisting of first and second signal processing means and a signal analyzer. The first ultrasonic wave propagation means has at least two
One input interdigital transducer Txi (i = 1, 2,..., M), at least two electrode groups Gxi (i = 1, 2,..., M), first and second piezoelectric substrates, Terminals Uxj (j = 1, 2, ...,
n). One of two adjacent electrode groups Gxi is composed of at least two output IDTs Rxaj (j = 1, 2,..., N), and the other is at least two output IDTs Rxbj (j = 1, 2). 2, ..., n). Output IDT R
xaj and Rxbj have opposite electrode finger directions. The terminals Uxj are respectively connected to the output IDTs Rxaj and also connected to the output IDTs Rxbj. The second ultrasonic wave propagation means includes at least two interdigital transducers Tyi (i = 1, 2,..., M), at least two electrode groups Gyi (i = 1, 2,. And a fourth piezoelectric substrate, and at least two terminals Uyj (j = 1, 2,..., N). Two adjacent ones of the electrode group Gyi include at least two output IDTs Ryaj (j = 1, 2,..., N),
The other has at least two output interdigital transducers Rybj
(j = 1, 2,..., n). The directions of the output interdigital electrodes Ryaj and Rybj are opposite to each other. Terminal Uyj
Are connected to the output interdigital electrodes Rybj, respectively, and are connected to the output interdigital electrodes Rybj, respectively. The input interdigital transducer Txi, the electrode group Gxi, the input interdigital transducer Tyi and the electrode group Gyi are the first on the upper end face of the non-piezoelectric plate,
They are provided on the second, third and fourth edges, respectively.
The first, second, third, and fourth piezoelectric substrates are provided on the input IDT Txi, the electrode group Gxi, the input IDT Tyi, and the electrode group Gyi, respectively. The first signal processing means includes a fifth piezoelectric substrate, first, second, and third electrode pairs provided on the fifth piezoelectric substrate, and a first synchronization pulse generator. The second signal processing means includes a sixth piezoelectric substrate, fourth, fifth, and sixth electrode pairs provided on the sixth piezoelectric substrate, and a second synchronous pulse generator. Signal analyzer is the first
And the second signal processing means.

In the ultrasonic touch panel system according to the present invention, if the first input electric signal is the input IDT,
When the voltage is simultaneously applied to two adjacent i's, the first surface acoustic wave is excited on the first piezoelectric substrate. At this time, since the first piezoelectric substrate is made of piezoelectric ceramic and the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction, the first surface acoustic wave is efficiently excited on the first piezoelectric substrate. . Further, if the phase velocity of the first surface acoustic wave is substantially equal to the phase velocity of the Rayleigh wave of the surface acoustic wave propagating in the non-piezoelectric plate itself, the first input electric signal is highly efficiently converted to the first surface acoustic wave. Is converted. The first surface acoustic wave travels along the upper end surface of the non-piezoelectric plate, and is not leaked into the non-piezoelectric plate.
Propagated to the piezoelectric substrate. The first surface acoustic wave is not leaked into the non-piezoelectric plate because, first, the thickness of the first piezoelectric substrate is smaller than the electrode period length of the input interdigital transducer Txi. The thickness of the plate is the interdigital transducer Txi for input.
Greater than three times the electrode period length, and thirdly,
This is because the phase velocity of the first surface acoustic wave propagating through the non-piezoelectric plate itself is higher than the phase velocity of the first surface acoustic wave propagating through the first piezoelectric substrate itself. The first transmitted to the second piezoelectric substrate
The surface acoustic wave is converted into a first output electric signal at each of the output IDTs Rxaj and Rxbj. At this time,
The first output electric signal at the output interdigital transducer Rxaj and the first output electric signal at the output interdigital transducer Rxbj have opposite phases. Therefore, no electric signal appears at all terminals Uxj. In this way, a total of (i × j) first electrodes are provided between the input interdigital transducer Txi and the electrode group Gxi.
A surface acoustic wave propagation path is formed. Similarly, if the second input electric signal is adjacent to the input IDT
Simultaneously, the second surface acoustic wave is excited in the third piezoelectric substrate. The second surface acoustic wave is propagated to the fourth piezoelectric substrate via the upper end surface of the non-piezoelectric plate, and is converted into a second output electric signal at each of the output IDTs Ryaj and Rybj. In this manner, the input interdigital transducer Tyi
A total of (i × j) second surface acoustic wave propagation paths are formed between and the electrode group Gyi.

If there is no contact with any part of the upper end surface of the non-piezoelectric plate, no delayed electric signal appears anywhere on the terminals Uxj and Uyj. However, by contacting somewhere on the upper end surface of the non-piezoelectric plate, a first delayed electric signal appears at one of the terminals Uxj, and a second delayed electric signal appears at one of the terminals Uyj. The second delayed electrical signal is detected by a signal analyzer. The first delayed electrical signal reaches the signal analyzer at the same time as the first electrode pair and the first synchronization pulse generator 1.
3 and reach the second pair of electrodes. When the first delayed electric signal is applied to the first and second electrode pairs, third and fourth surface acoustic waves are excited on the fifth piezoelectric substrate, respectively. Here, the fourth surface acoustic wave is excited by a pulse signal of the same polarity from the first synchronous pulse generator. Third and fourth
The surface acoustic wave reaches the third pair of electrodes, and as a result, the first delayed electric signal is converted into a first composite burst signal. First
The amplitude state of the composite burst signal is determined in a signal analyzer. Similarly, when the second delayed electric signal is applied to the fourth and fifth electrode pairs, the fifth and sixth surface acoustic waves are excited on the sixth piezoelectric substrate, respectively. At the same time as the fifth surface acoustic wave reaches the sixth electrode pair, the sixth surface acoustic wave reaches the sixth electrode pair via the second synchronous pulse generator. As a result, the second delayed electric signal is converted into a second synthesized burst signal, and its amplitude state is determined in the signal analyzer. In this manner, the contact position corresponding to the intersection of the first and second surface acoustic wave propagation paths can be determined from the phases of the first and second delayed electric signals.

In the ultrasonic touch panel system according to the present invention, the first, second, third and fourth piezoelectric substrates can be integrated into one window frame structure. By adopting such a structure, the manufacturing process can be simplified.

In the ultrasonic touch panel system of the present invention, a structure including first and second switches connected to the input IDTs Txi and Tyi is possible. By employing such a structure, the circuit configuration can be simplified.

[0016]

FIG. 1 is a plan view showing one embodiment of a panel section included in an ultrasonic touch panel system according to the present invention. The ultrasonic touch panel system includes first and second ultrasonic wave propagation means, first and second signal processing means, a non-piezoelectric plate 1, a signal analyzer 2, a first switch 3 and a second switch 4. The first ultrasonic wave propagation means includes a first piezoelectric substrate 5, a second piezoelectric substrate 6, input IDTs Tx1, Tx2, Tx3, Tx4 and Tx.
5, electrode group Gx1, Gx2, Gx3, Gx4 and Gx5, and terminal Ux
1, consisting of Ux2 and Ux3. Each of the electrode groups Gx1, Gx3 and Gx5 is made up of output interdigital electrodes Rxa1, Rxa2 and Rxa3. Each of the electrode groups Gx2 and Gx4 is made up of output interdigital electrodes Rxb1, Rxb2 and Rxb3. The second ultrasonic wave propagation means includes a third piezoelectric substrate 7, a fourth piezoelectric substrate 8, input IDTs Ty1, Ty2, Ty3, Ty4, and Ty5, and electrode groups Gy1, Gy2, Gy.
3, consisting of Gy4 and Gy5, and terminals Uy1, Uy2 and Uy3. Each of the electrode groups Gy1, Gy3, and Gy5 is composed of output interdigital electrodes Rya1, Rya2, and Rya3. Each of the electrode groups Gy2 and Gy4 is an output interdigital electrode Ryb1, Ryb2 and R
Consists of yb3. Input IDTs Tx1, Tx2, Tx3, Tx4
And Tx5, electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5, input IDTs Ty1, Ty2, Ty3, Ty4 and Ty5, electrode group G
y1, Gy2, Gy3, Gy4 and Gy5 are provided on the first, second, third and fourth edges of the upper end surface of the non-piezoelectric plate 1, respectively. The first piezoelectric substrate 5 has IDT electrodes Tx1, Tx2,
The second piezoelectric substrate 6 is provided on Tx3, Tx4 and Tx5, and the second piezoelectric substrate 6 is provided on the electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5,
The third piezoelectric substrate 7 has IDT electrodes Ty1, Ty2, Ty3, T for input.
The fourth piezoelectric substrate 8 is provided on y4 and Ty5, and the electrode group G
It is provided on y1, Gy2, Gy3, Gy4 and Gy5. At this time, instead of the first piezoelectric substrate 5, the second piezoelectric substrate 6, the third piezoelectric substrate 7, and the fourth piezoelectric substrate 8, one window frame type piezoelectric substrate formed by integrating them is provided. Can be used. Non-piezoelectric plate 1, first piezoelectric substrate 5, second piezoelectric substrate 6, third piezoelectric substrate 7, fourth piezoelectric substrate 8, input IDTs Tx1, Tx2, Tx3, Tx4, Tx5, Ty1,
Ty2, Ty3, Ty4 and Ty5, electrode groups Gx1, Gx2, Gx3, Gx4,
Gx5, Gy1, Gy2, Gy3, Gy4 and Gy5 form a panel part. In FIG. 1, a first piezoelectric substrate 5, a second piezoelectric substrate 6, a third
The piezoelectric substrate 7 and the fourth piezoelectric substrate 8 are not shown. The non-piezoelectric plate 1 is made of a transparent glass plate, and the phase velocity of the surface acoustic wave propagating on the non-piezoelectric plate 1 itself is faster than the phase velocity of the surface acoustic wave propagating on the first piezoelectric substrate 5 itself. Input IDTs Tx1, Tx2, Tx3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4
And Ty5, electrode groups Gx1, Gx2, Gx3, Gx4, Gx5, Gy1, Gy
2, Gy3, Gy4 and Gy5 are each made of an aluminum thin film. The first piezoelectric substrate 5, the second piezoelectric substrate 6, the third piezoelectric substrate 7, and the fourth piezoelectric substrate 8 are made of piezoelectric ceramic, and the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction.

FIG. 2 is a partially enlarged plan view of the panel portion.
FIG. 2 shows only the electrode groups Gx1 and Gx2 provided on the non-piezoelectric plate 1. As described above, the electrode group Gx1 corresponding to the input IDT Tx1 is the output IDT Rx.
a1, Rxa2 and Rxa3, and the input IDT Tx2
The electrode group Gx2 corresponding to the output IDTs Rxb1 and Rxb2
And Rxb3. Input IDTs Tx1, Tx2, Tx
3, Tx4, Tx5, Ty1, Ty2, Ty3, Ty4 and Ty5 have a similar structure, and the electrode cycle length is 400 μm. Electrode group Gx1, Gx
2, Gx3, Gx4, Gx5, Gy1, Gy2, Gy3, Gy4 and Gy5 have a similar structure, and the electrode period length is 400 μm. However, the directions of the electrode fingers of the output interdigital electrodes Rxa1, Rxa2, and Rxa3 are opposite to those of the output interdigital electrodes Rxb1, Rxb2, and Rxb3. Similarly, the output interdigital electrodes Rya1, Rya2 and Rya3 and the output interdigital electrode Ryb
In 1, Ryb2 and Ryb3, the directions of the electrode fingers are opposite to each other.

FIG. 3 is a sectional view of the panel portion. The thickness of the non-piezoelectric plate 1 is 1.5 mm. The thickness of the first piezoelectric substrate 5, the second piezoelectric substrate 6, the third piezoelectric substrate 7, and the fourth piezoelectric substrate 8 is 15
0 μm.

FIG. 4 is a configuration diagram showing an embodiment of the ultrasonic touch panel system. The non-piezoelectric plate 1, the first piezoelectric substrate 5, the second piezoelectric substrate 6, the third piezoelectric substrate 7, and the fourth piezoelectric substrate 8 are not shown in FIG. Terminals Ux1, Ux2 and Ux
3 is connected to the output interdigital electrodes Rxa1, Rxa2 and Rxa3, respectively, and the output interdigital electrodes Rxb1 and Rxb2
And Rxb3. The terminals Uy1, Uy2 and Uy3 are connected to the output interdigital electrodes Rya1, Rya2 and Rya3.
And the output interdigital electrode Ry
b1, Ryb2 and Ryb3, respectively. The first signal processing means includes a fifth piezoelectric substrate 9, a first electrode pair 10, a second electrode pair 11, a third electrode pair 12, and a first synchronous pulse generator 13. The first electrode pair 10, the second electrode pair 11, and the third electrode pair 12 are provided on the fifth piezoelectric substrate 9. The second signal processing means includes a sixth piezoelectric substrate 14, a fourth electrode pair 15,
It comprises a fifth electrode pair 16, a sixth electrode pair 17, and a second synchronization pulse generator 18. Fourth electrode pair 15, fifth electrode pair 16
The sixth electrode pair 17 is provided on the sixth piezoelectric substrate 14. The signal analyzer 2 is connected to the first and second signal processing means. Fifth piezoelectric substrate 9 and sixth piezoelectric substrate 14
Is made of a piezoelectric ceramic, and the direction of the polarization axis of the piezoelectric ceramic is parallel to its thickness direction.

In the ultrasonic touch panel system of FIG. 4, if the first input electric signal is the IDT Tx1 for input.
And Tx2 are applied simultaneously via the first switch 3,
A first surface acoustic wave is excited in the first piezoelectric substrate 5. The first surface acoustic wave propagates along the upper end surface of the non-piezoelectric plate 1 and propagates to the second piezoelectric substrate 6 without leaking into the non-piezoelectric plate 1. The first surface acoustic wave propagated to the second piezoelectric substrate 6 is:
The output interdigital electrodes Rxa1, Rxa2, and Rxa3 included in the electrode group Gx1, and the output interdigital electrodes R included in the electrode group Gx2
Each of xb1, Rxb2 and Rxb3 is converted into a first output electric signal. At this time, the first output electric signals at the output interdigital transducers Rxa1, Rxa2, and Rxa3 of the electrode group Gx1, and the output interdigital transducers Rxb1, Rxb2, and Rx of the electrode group Gx2.
The first output electrical signals at xb3 are out of phase with each other. Therefore, no electric signal appears at the terminals Ux1, Ux2 and Ux3. Generally, when the first input electric signal is simultaneously applied to two adjacent ones of the IDT electrodes Tx1, Tx2, Tx3, Tx4 and Tx5, the first surface acoustic wave is excited in the first piezoelectric substrate 5. Is done. The first surface acoustic wave propagates along the upper end surface of the non-piezoelectric plate 1 and propagates to the second piezoelectric substrate 6, and the electrode group Gx
The output interdigital electrodes Rxa1, Rxa2, Rxa3, Rxb1, Rxb2 and Rxb3 included in two adjacent ones of 1, Gx2, Gx3, Gx4 and Gx5 are converted into a first output electric signal. Thus, the input IDTs Tx1, Tx2, Tx3, Tx4 and Tx5
Thus, a total of 15 first surface acoustic wave propagation paths are formed between the electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5.

If the second input electric signal is simultaneously applied to the adjacent two of the input IDTs Ty1, Ty2, Ty3, Ty4 and Ty5, a second surface acoustic wave is excited on the third piezoelectric substrate 7. You. The second surface acoustic wave propagates along the upper end surface of the non-piezoelectric plate 1 to the fourth piezoelectric substrate 8, and is applied to the electrode groups Gy1, Gy2,
The output interdigital electrodes Rya1, Rya2, Rya3, Ryb1, Ryb2 and Ryb3 included in two adjacent ones of Gy3, Gy4 and Gy5 are converted into the second output electric signal. In this way, a total of 15 second surface acoustic wave propagation paths are formed between the input IDTs Ty1, Ty2, Ty3, Ty4, and Ty5 and the electrode groups Gy1, Gy2, Gy3, Gy4, and Gy5. You.

In the ultrasonic touch panel system shown in FIG.
If it does not contact anywhere on the upper end surface of the non-piezoelectric plate 1,
No delayed electrical signal appears anywhere at terminals Ux1, Ux2, Ux3, Uy1, Uy2 and Uy3. However, by contacting somewhere on the upper end surface of the non-piezoelectric plate 1, the terminals Ux1, Ux2 and
A first delayed electrical signal appears on one of the Ux3 terminals Uy3
A second delayed electrical signal appears on one of 1, Uy2 and Uy3. These first and second delayed electric signals are detected by the signal analyzer 2. For example, the input IDTx2
A first surface acoustic wave propagation path between the electrode group Gx2 and the output interdigital electrode Rxb3, and the input interdigital electrode Ty1 and the electrode group Gy1.
Contacting the intersection of the second surface acoustic wave propagation path with the output interdigital transducer Rya2, a first delayed electric signal appears at the terminal Ux3, and a second delayed electric signal appears at the terminal Uy2. However,
At this time, it is assumed that the first input electric signal is applied to the IDT electrodes Tx2 and Tx3, and the second input electric signal is applied to the IDT electrodes Ty1 and Ty2. In this case, the first delayed electric signal appearing at the terminal Ux3 is the electrode group Gx3
The second delayed electrical signal appearing at the terminal Uy2 corresponds to the first output electrical signal at the output interdigital transducer Rxa3, and the second output electrical signal at the output interdigital transducer Ryb2 of the electrode group Gy2. Corresponding. This is because the first surface acoustic wave between the input IDT Tx2 and the output IDT Rxb3 of the electrode group Gx2, and the input IDT Ty1 and the output IDT Rya2 of the electrode group Gy1. This is because the intervening second surface acoustic waves disappear by contacting the intersections of the first and second surface acoustic wave propagation paths corresponding to the first and second surface acoustic waves, respectively.

First signal processing means is used to determine the phase state of the first delayed electric signal. The first delayed electric signal reaches the signal analyzer 2 and, at the same time, reaches the second electrode pair 11 via the first electrode pair 10 and the first synchronization pulse generator 13. When the first delayed electric signal is the first electrode pair 10
When applied to the second electrode pair 11, the fifth piezoelectric substrate 9
Then, the third and fourth surface acoustic waves are excited. Here, the fourth surface acoustic wave is excited by a pulse signal of the same polarity from the first synchronous pulse generator 13. The third and fourth surface acoustic waves reach the third electrode pair 12, and as a result, the first delayed electric signal is converted into a first composite burst signal. The amplitude state of the first synthesized burst signal is determined by reaching the signal analyzer 2. Depending on the amplitude state of the first combined burst signal, which of the two adjacent ones of the electrode groups Gx1, Gx2, Gx3, Gx4 and Gx5 is involved in the first delayed electric signal appearing at one of the terminals Ux1, Ux2 and Ux3 You know

Similarly, a second signal processing means is used to determine the phase state of the second delayed electric signal. When the second delayed electric signal is applied to the fourth electrode pair 15 and the fifth electrode pair 16, fifth and sixth surface acoustic waves are excited on the sixth piezoelectric substrate 14, respectively. At the same time that the fifth surface acoustic wave reaches the sixth electrode pair 17, the sixth surface acoustic wave is transmitted via the second synchronization pulse generator 18 to the sixth electrode pair 17.
To reach. As a result, the second delayed electric signal is converted into a second synthesized burst signal, and the signal analyzer 2 determines its amplitude state. Depending on the amplitude state of the second combined burst signal, which of two adjacent ones of the electrode groups Gy1, Gy2, Gy3, Gy4 and Gy5 is involved in the second delayed electric signal appearing at one of the terminals Uy1, Uy2 and Uy3. You know In this manner, the contact position corresponding to the intersection of the first and second surface acoustic wave propagation paths can be determined from the phases of the first and second delayed electric signals.

FIG. 5 is a characteristic diagram showing the relationship between the electromechanical coupling coefficient k ² and the fd value. However, fd value represents the product of the thickness d of the frequency f of the first surface acoustic wave first piezoelectric substrate 5, k ² values two electrical boundary conditions of different first piezoelectric substrate 5, namely electric It is calculated from the phase velocity difference between the target open state and the short circuit state. The speed of the transverse wave propagating through the non-piezoelectric plate 1 is 3,091
m / s and longitudinal wave velocity is 5,592 m / s. Since the velocities of the transverse and longitudinal waves propagating through the first piezoelectric substrate 5 are 2,450 m / s and 4,390 m / s, respectively, the velocities of the transverse and longitudinal waves in the non-piezoelectric plate 1 are the same as those in the first piezoelectric substrate 5. It can be seen that the speed is almost 1.3 times as fast as the speed. From FIG. 5, fd
4.7 k ² value of the primary mode when the value is 1.3 MHzmm is maximum
%. That is, it is understood that the first-order mode surface acoustic wave is most efficiently excited by the first piezoelectric substrate 5, and the fd value at that time is 1.3 MHzmm.

FIG. 6 is a characteristic diagram showing a velocity dispersion curve of a surface acoustic wave propagating through the layered structure of the non-piezoelectric plate 1 and the first piezoelectric substrate 5. The maximum value of the k ² value in each mode is obtained from FIG. 5 and is indicated by a black circle in FIG. The phase velocity at each mark ● is approximately 2,980 m / s, which is the phase velocity of the Rayleigh wave propagating through the non-piezoelectric plate 1 itself at 2,850 m / s.
It turns out that it is almost equal to s.

FIG. 7 is a characteristic diagram showing a displacement distribution of a first-order mode surface acoustic wave propagating through the layered structure of the non-piezoelectric plate 1 and the first piezoelectric substrate 5. The depth of the layered structure is normalized by the d value, and the displacement is normalized by setting the maximum value to 1. The vertical component of the surface acoustic wave is indicated by a solid line, and the horizontal component is indicated by a broken line. FIG. 7 shows that both the vertical component and the horizontal component exist near the boundary between the non-piezoelectric plate 1 and the first piezoelectric substrate 5. That is, it is understood that both components are not leaked to the deep part of the non-piezoelectric plate 1.

[0028]

The ultrasonic touch panel system according to the present invention comprises a non-piezoelectric plate, first and second ultrasonic wave propagating means, first and second signal processing means, and a signal analyzer, and is small and lightweight. The configuration is simple, and the circuit configuration is also simple.
Therefore, mass production is possible. Further, since a glass plate or the like can be used as the non-piezoelectric plate, it has excellent durability, and can cope with frequent use and complicated use.

In the ultrasonic touch panel system of the present invention, the terminals Uxj
A first delayed electrical signal appears at one of the terminals, and a second delayed electrical signal appears at one of the terminals Uyj. These first and second delayed electric signals are directly detected by the signal analyzer and reach the signal analyzer via the first and second signal processing means. In this way, the phase state of each of the first and second delayed electric signals becomes clear, and it becomes possible to determine the contact position with high sensitivity from these phases.

In the ultrasonic touch panel system of the present invention, the first, second, third and fourth piezoelectric substrates can be integrated into one window frame structure. By adopting such a structure, the manufacturing process can be simplified.

In the ultrasonic touch panel system of the present invention, a structure including first and second switches connected to the input IDTs Txi and Tyi, respectively, is possible. By employing such a structure, the circuit configuration can be simplified.

[Brief description of the drawings]

FIG. 1 is a plan view showing one embodiment of a panel unit included in an ultrasonic touch panel system of the present invention.

FIG. 2 is a partially enlarged plan view of a panel unit.

FIG. 3 is a sectional view of a panel unit.

FIG. 4 is a configuration diagram showing one embodiment of an ultrasonic touch panel system.

[5] characteristic diagram showing the relationship between the electromechanical coupling factor k ² and fd value.

FIG. 6 is a characteristic diagram showing a velocity dispersion curve of a surface acoustic wave propagating through a layered structure of the non-piezoelectric plate 1 and the first piezoelectric substrate 5.

FIG. 7 is a characteristic diagram showing a displacement distribution of a first-order mode surface acoustic wave propagating through a layered structure of the non-piezoelectric plate 1 and the first piezoelectric substrate 5.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 non-piezoelectric plate 2 signal analyzer 3 first switch 4 second switch 5 first piezoelectric substrate 6 second piezoelectric substrate 7 third piezoelectric substrate 8 fourth piezoelectric substrate 9 fifth piezoelectric substrate 10 first electrode pair 11 second electrode Pair 12 Third electrode pair 13 First synchronous pulse generator 14 Sixth piezoelectric substrate 15 Fourth electrode pair 16 Fifth electrode pair 17 Sixth electrode pair 18 Second synchronous pulse generator Tx1, Tx2, Tx3, Tx4, Tx5 Input IDT electrodes Gx1, Gx2, Gx3, Gx4, Gx5 Electrode group Ux1, Ux2, Ux3 terminals Rxa1, Rxa2, Rxa3, Rxb1, Rxb2, Rxb3 Electrodes Gy1, Gy2, Gy3, Gy4, Gy5 Electrode group Uy1, Uy2, Uy3 terminals Rya1, Rya2, Rya3, Ryb1, Ryb2, Ryb3 Interdigital electrodes

Claims (7)

[Claims] 1. An ultrasonic touch panel system comprising a non-piezoelectric plate, first and second ultrasonic wave propagation means, first and second signal processing means, and a signal analyzer, wherein the first
The ultrasonic wave propagation means has at least two interdigital transducers
Txi (i = 1, 2, ..., m) and at least two electrode groups Gxi (i =
1, 2,..., M), first and second piezoelectric substrates, and at least two terminals Uxj (j = 1, 2,.
Two adjacent ones of Gxi are composed of at least two output interdigital transducers Rxaj (j = 1, 2,..., N), and the other is at least two output interdigital transducers Rxbj (j = 1, 2, …,
n), the output IDTs Rxaj and Rxbj
The directions of the electrode fingers are opposite to each other, and the terminal Uxj is
Connected to the output interdigital transducer Rxaj, respectively, and connected to the output interdigital transducer Rxbj, respectively, the second ultrasonic wave propagating means includes at least two input interdigital transducers Tyi (i = 1, 2, , M), at least two electrode groups Gyi (i = 1, 2,..., M), third and fourth piezoelectric substrates, and at least two terminals Uyj (j = 1, 2,..., N). One of the two adjacent electrode groups Gyi consists of at least two output interdigital transducers Ryaj (j = 1, 2,..., N), and the other has at least two output interdigital transducers Ryj.
bj (j = 1, 2,..., n), and the output interdigital transducer R
yaj and Rybj have opposite electrode finger directions, and the terminals Uyj are respectively connected to the output IDTs Ryaj and connected to the output IDTs Rybj and the input IDTs, respectively. Electrode Txi, the electrode group Gxi, the input IDT Tyi and the electrode group
Gyi is provided at first, second, third and fourth edges of an upper end surface of the non-piezoelectric plate, respectively, and the first, second, third and fourth piezoelectric substrates are provided with the input interdigital transducer. Txi, the electrode group Gxi, the input interdigital transducer Tyi, and the electrode group Gyi. The first signal processing means is provided on a fifth piezoelectric substrate, and the first signal processing means is provided on the fifth piezoelectric substrate. , A second and a third pair of electrodes, and a first synchronization pulse generator, wherein the second signal processing means comprises a sixth piezoelectric substrate and fourth, fifth and sixth electrodes provided on the sixth piezoelectric substrate. The signal analyzer is connected to the first and second signal processing means, and a first input electric signal is applied to two adjacent ones of the input IDTs. As a result, the first surface acoustic wave is excited on the first piezoelectric substrate, and the first Sexual surface wave is propagated through the upper end surface of the non-piezoelectric plate to said second piezoelectric substrate,
Each of the output interdigital transducers Rxaj and Rxbj is converted into a first output electrical signal,
When a second input electric signal is applied to two adjacent Tyi, a second surface acoustic wave is excited on the third piezoelectric substrate, and the second surface acoustic wave is applied to the upper end surface of the non-piezoelectric plate. Is transmitted to the fourth piezoelectric substrate, and is converted into a second output electric signal at each of the output IDTs Ryaj and Rybj, and by contacting the upper end surface of the non-piezoelectric plate, the terminal Uxj The first and second delayed electrical signals appearing at one and one of the terminals Uyj, respectively, are directly detected by the signal analyzer and after passing through the first and second signal processing means. And the contact position on the upper end surface of the non-piezoelectric plate is the first position detected by the signal analyzer.
And an ultrasonic touch panel system determined by the phase of the second delayed electric signal. 2. The window frame structure according to claim 1, wherein said first, second, third and fourth piezoelectric substrates are integrated.
The ultrasonic touch panel system according to 1. 3. The piezoelectric substrate according to claim 1, wherein said first, second, third, fourth, fifth, and sixth piezoelectric substrates are made of piezoelectric ceramic, and a direction of a polarization axis of said piezoelectric ceramic is parallel to a thickness direction thereof. 3. The ultrasonic touch panel system according to 1 or 2. 4. The ultrasonic touch panel system according to claim 1, wherein said non-piezoelectric plate is made of a transparent material. 5. A thickness of said first, second, third and fourth piezoelectric substrates is smaller than an electrode cycle length of said input IDTs Txi and Tyi, and a thickness of said non-piezoelectric plate is smaller than said electrode. 5. The ultrasonic touch panel system according to claim 1, wherein the period is longer than three times the cycle length. 6. The phase velocity of the surface acoustic wave propagating to the non-piezoelectric plate itself is faster than the phase velocity of the surface acoustic wave propagating to the first, second, third, and fourth piezoelectric substrates themselves. , 2, 3, 4 or 5. 7. The ultrasonic touch panel system according to claim 1, further comprising first and second switches connected to the input interdigital transducers Txi and Tyi, respectively.