JPH1055239A - Ultrasonic touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To decide a contact position without being affected by a light hand touch on the panel and the sticking of a small amount of foreign matter on the panel. SOLUTION: Ultrasonic wave transmitting and receiving means X and Y which have mutually orthogonal propagation paths excite unidirectional elastic waves in two-layered structure parts LTXi and LTYi respectively and propagate them in an acryl plate 1, and propagates them in two-layered structure parts LRX and LRY respectively and outputting those waves as electric signals. When the intersection part of propagation paths UXi and UYi on the acryl plate 1 is touched, those output electric signals are attenuated or ceased, so the contact position can be decided.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention provides a non-piezoelectric plate having a piezoelectric plate having interdigital electrodes so that the pen tip of an input pen contacts the non-piezoelectric plate surface with a pressure exceeding a predetermined value. The present invention relates to an ultrasonic touch panel for specifying the coordinates of a position where the touch panel is located.

2. Description of the Related Art Conventional touch panels mainly include a method using a resistive film and a method using ultrasonic waves. The method using a resistive film is based on the fact that the resistance value of the transparent conductive film changes when it comes into contact with the transparent conductive film (resistive film). There is a problem in terms of properties. In addition, there is a disadvantage that it is difficult to increase the area of the panel. The method using ultrasonic waves utilizes the fact that surface acoustic waves are attenuated by contact with a non-piezoelectric plate in which surface acoustic waves have been excited in advance. Conventional methods of exciting a surface acoustic wave to a non-piezoelectric plate include a method of indirectly exciting a wedge-shaped transducer using a bulk wave oscillator, and a method of directly exciting a piezoelectric thin film transducer. The wedge-shaped transducer is used for non-destructive inspection or the like by ultrasonic waves, but is used only in a relatively low frequency region due to the problem of machining accuracy of the wedge angle. Piezoelectric thin film transducer is ZnO
A method in which a piezoelectric thin film is deposited on a substrate and a surface acoustic wave is excited by an interdigital electrode. Since the interdigital electrode shows various transmission characteristics, it is used as a high-frequency device, but is limited to the UHF and VHF bands. In addition, there is a problem in workability and mass productivity. Thus, the response time, sensitivity, durability, work accuracy, workability,
There are problems in terms of mass productivity and ease of use, and the operating frequency range is also limited. Therefore, an ultrasonic touch panel that solves these problems has been filed by the present inventor in Japanese Patent Application No. 4-218336. This ultrasonic touch panel is provided with at least two ultrasonic devices comprising a piezoelectric thin plate and an interdigital electrode on one plate surface of a non-piezoelectric plate, and efficiently generates a surface acoustic wave with low power consumption on the non-piezoelectric plate. Can be excited on the surface. Therefore, if a finger or an object comes into contact with a surface acoustic wave propagation path on one surface of the non-piezoelectric plate, the surface acoustic wave is attenuated or eliminated, so that contact with the finger or the object is sensed. However, such a method using a surface acoustic wave has an advantage that it is easy to increase the area of the panel because it is less susceptible to electromagnetic noise, but it is affected by the magnitude of the contact pressure when contacting the panel. Since the response occurs without being performed, the sensitivity is high, but on the other hand, it has a disadvantage that it is liable to malfunction and is difficult to use. For example, in order to calculate the coordinates of the position by touching the panel with the pen tip of the input pen, touching the panel even by a small amount is not allowed. This is because touching the panel makes it impossible to calculate coordinates. Further, the panel is easily affected by a small amount of foreign matter attached to the panel. Further, in this ultrasonic touch panel, since ultrasonic waves are excited evenly in both directions perpendicular to the electrode fingers of the interdigital electrodes, not only was half of the ultrasonic energy wasted, but also the piezoelectric thin plate Depending on the thickness of the device, unnecessary signals were caused.

The conventional touch panel not only has problems in response time, sensitivity, durability, work precision, workability, mass productivity, ease of use, and the like.
There was also a problem in terms of waste of ultrasonic energy, how to support and unnecessary signals. An object of the present invention is to provide a process that is excellent in workability, durability and mass productivity, has a low response time with low power consumption driving, and is not affected by light hand touching on a panel or a small amount of foreign matter attached to a panel. An object of the present invention is to provide an ultrasonic touch panel excellent in ease of use.

An ultrasonic touch panel according to claim 1 comprises a non-piezoelectric plate, at least two ultrasonic wave transmitting and receiving means X and Y, and one of the non-piezoelectric plates or the other. A display screen displayed in at least one color provided on the plate surface of the ultrasonic touch panel comprising an information processing unit, wherein the information processing unit is provided on each of the ultrasonic wave transmitting / receiving means and the display screen. And each of the ultrasonic wave transmitting / receiving means is connected to N sets of interdigital electrodes I _Ti (i =
1, 2, a piezoelectric plate P _T with the N), and the piezoelectric plate P _R having the interdigital electrodes I _R, N number of switches C _i (i =
1, 2, made from a N), said interdigital transducer I _Ti
Is provided on one plate surface of said piezoelectric plate P _T, said interdigital transducer I _R is provided on one plate surface of said piezoelectric plate P _R, the piezoelectric plate P _T is the piezoelectric plate P _T Fixed to the non-piezoelectric plate via the one plate surface or the other plate surface,
It said piezoelectric plate P _R is not secured to the non-piezoelectric plate through the one plate surface or the other plate surface of the piezoelectric plate P _R, the piezoelectric plate P _T corresponding to the interdigital transducer I _Ti portion P _Ti to (i = 1,2, ......, N ) made in said non-piezoelectric plate includes a portion corresponding to the portion P _Ti, and a portion corresponding to the piezoelectric plate P _R, the switch C _i is an output terminal of which is connected to the input end of the interdigital transducer I _Ti, the interdigital transducer I _Ti is an electrical signal E _T of a frequency substantially corresponding to the interdigital periodicity p of the interdigital transducer I _Ti by being input, the portion P _Ti and said non-piezoelectric second layer consisting of the said partial P _Ti corresponding portion of the plate structure portion L _Ti (i
= 1,2, ..., the elastic wave is excited in N), by propagating elastic waves in the non-piezoelectric plate, the elastic wave excited in the two-layer structure L _Ti is S ₀ mode and 1 In higher order mode waves, the wavelength of the elastic wave is substantially equal to the electrode period length p of the interdigital transducer I _Ti , and the phase velocity of the elastic wave is
The product KD of the wave number K of the elastic wave and the thickness D of the piezoelectric plate _PT
Is approximately equal to the phase velocity V _{kd = 0} of the elastic wave in the S ₀ mode when is zero, and the interdigital transducer I _R transmits the elastic wave propagated in the non-piezoelectric plate to the piezoelectric plate P _R and the non-piezoelectric plate. the propagate a two-layer structure L _R consisting of the portion corresponding to the piezoelectric plate P _R of the piezoelectric plate, wherein the elastic wave propagating in the two-layer structure L _R IDT I interdigital periodicity of _R p and converts almost corresponding to the electric signal E _R of the frequency, the two-layer structure L _R
Is the wavelength of the elastic wave propagating almost equal to the interdigital periodicity p of the interdigital transducer I _R, the phase velocity of the elastic wave, the thickness D of the wavenumber K of the elastic wave piezoelectric plate P _R Is zero, the phase velocity V _{kd = 0} of the elastic wave in the S ₀ mode when the product KD is zero
And the thickness D of each of the piezoelectric plates is approximately equal to or less than each of the electrode period lengths p, and the thickness of the non-piezoelectric plate is approximately equal to the thickness D of each of the piezoelectric plates or Above that, it is less than about 2.5 times the thickness D of each piezoelectric plate, and the phase velocity of the elastic wave propagating to the non-piezoelectric plate alone is the phase velocity of the elastic wave propagating to each piezoelectric plate alone. smaller than, the information processing unit is intermittently by sequentially predetermined cycle said switch C _i, detects the magnitude of the electric signal E _R, the plate surface of the side not having the display screen in the non-piezoelectric plate determined by the fact that the pen tip of the input pen on contacts at a pressure exceeding a predetermined value is the magnitude of the electrical signal E _R attenuated or abolished, the magnitude of the electrical signal E _R is attenuated or eliminated By identifying the switch C _i that was connected at the time, The contact position is identified, and information corresponding to the identified contact position is displayed on the display screen. Ultrasonic touch panel as set forth in claim 2, wherein the channel U _Xi (i = 1 of the acoustic wave between said two-layer structure L _Ti in ultrasonic transmitter means X the two-layer structure L _R, 2,
.., N), and the 2 in the ultrasonic wave transmitting / receiving means Y.
The elastic wave propagation paths U _Yi (i = 1, 2,..., N) between the layer structure part L _Ti and the two-layer structure part L _R are orthogonal to each other. In the ultrasonic touch panel according to claim 3, the propagation paths U _Xi are adjacent to each other or partially overlap each other, and the propagation paths U _Yi are adjacent to each other or partially overlap each other. 5. The ultrasonic touch panel according to claim 4, wherein an oscillator H _i (i = 1, 2,..., N) having the propagation paths U _Xi and U _Yi as delay elements is configured, and the ultrasonic transmission / reception is performed. input of the switch C _i in unit X, the are connected via an amplifier a _Y to the output terminal of the interdigital transducer I _R in ultrasonic transmitter unit Y, wherein the ultrasonic transmitter means Y input of switch C _i, the are connected via an amplifier a _X to the output of the interdigital transducer I _R in ultrasonic transmitter unit X, the signal loop of the oscillator H _i, the ultrasonic transmitting and receiving Wave means X
The switch C _i, the channel U _Xi in the amplifier A _X, and the said switch C _i in ultrasonic transmitter unit Y, the channel U _Yi, comprising the amplifier A _Y.
The ultrasonic touch panel according to claim 5, wherein a non-piezoelectric plate,
At least two ultrasonic transmitting and receiving means X and Y, a display screen provided in at least one color provided on one plate surface or the other plate surface of the non-piezoelectric plate, and an information processing unit. An ultrasonic touch panel, wherein the information processing unit is connected to each of the ultrasonic wave transmitting / receiving means and the display screen, and each of the ultrasonic wave transmitting / receiving means comprises N sets of interdigital transducers T _i (i = 1 , 2, ......, N) and N ground electrode _{G Ti (i = 1,2, ......} , comprising: a piezoelectric plate P _T having a N), the IDT R and the ground electrode G _R piezoelectric a plate P _R, phase shifter S _T and phase shifter S _R and, N sets of switches _{W i (i = 1,2, ......} , N) become from and, wherein the interdigital transducer T _i the piezoelectric provided on one plate surface of the plate P _T, the ground electrode G _Ti is provided on the other plate surface of the piezoelectric plate P _T, Serial IDT R is provided on one plate surface of said piezoelectric plate P _R, the ground electrode G _R provided on the other plate surface of the piezoelectric plate P _R, the piezoelectric plate P _T
Is fixed to the non-piezoelectric plate via the ground electrode G _Ti ,
Said piezoelectric plate P _R is not secured to the non-piezoelectric plate via the ground electrode G _R, the piezoelectric plate P _T is part P _Ti (i = 1,2 corresponding to the interdigital transducer T _i, ... ... consists in N), the non-piezoelectric plate includes a portion corresponding to the portion P _Ti, and a portion corresponding to the piezoelectric plate P _R, the IDT T _i, the electrode T _i-1 and T _i-2 , the electrode T
There are two types of distance between the electrode finger of _{i-1 and} the electrode finger of the electrode T _i-2 , and the switch _Wi includes a switch _Wi-1 and a switch _Wi-2 , and the switch _{Wi -1} is connected to the input terminal of the electrode T _i-1 , the output terminal of the switch W _i-2 is connected to the input terminal of the electrode T _i-2 , and the phase shifter S _T comprises at least one coil L _1, the coil L ₁ is connected to an input terminal of the switch W _i-1 or W _i-2, the interdigital electrode T _i and the ground electrode G _Ti is , The electrode T _i-1 and the ground electrode G
By inputting the electrical signals E _T1 and E _T2 having a phase difference 2πy through the phase shifter S _T between and between the electrode T _i-2 and the ground electrode G _Ti and _Ti, the part P _Ti and, wherein the portion P 2 layer structure consisting of a portion corresponding to _Ti L _Ti of the non-piezoelectric plate (i = 1,2, ......, N )
And the frequency of the electric signals E _T1 and E _T2 substantially corresponds to the electrode period length p of the interdigital transducer T _i , and the elastic wave is propagated through the non-piezoelectric plate. 2
The elastic wave excited in the layer structure part L _Ti is a wave of S ₀ mode and a first-order or higher-order mode, and the wavelength of the elastic wave is substantially equal to the electrode period length p of the interdigital transducer T _i . The phase velocity of the elastic wave is determined by the wave number K of the elastic wave and the piezoelectric plate P.
_When the product KD of _{T and} the thickness D is zero, the phase velocity V _{kd = 0} of the elastic wave in the S ₀ mode is almost equal to the interdigital electrode R.
Consists electrode R _-1 and R _-2, there are two types of distance between the electrode fingers of the electrode R _-1 and the electrode fingers of the electrode R _-2, the phase shifter S _R is at least one coil comprises L _2, the coil L ₂ is connected to the output terminal of the electrode R _-1 or R _-2, the IDT R and the ground electrode G _R
, The elastic wave that is propagated in a non-piezoelectric plate and the piezoelectric plate P _R, propagate the two-layer structure L _R consisting of the portion corresponding to the piezoelectric plate P _R of the non-piezoelectric plate, the two-layer structure L the acoustic wave propagating in _R as the electric signals E _R1 and E _R2 having a phase difference 2πy the the electrode R _-1 ground electrode G
Outputs from and between the said electrode R _-2 and the ground electrode G _R and _R, the phase shifter S _R is the electrical signal E _R1 and E
_R2 is combined with an electric signal E _R of the same phase and output. The frequency of the electric signals E _R1 and E _R2 substantially corresponds to the electrode period length p of the interdigital transducer R. _R
Is the wavelength of the elastic wave propagating almost equal to the interdigital periodicity p of the interdigital transducer I _R, the phase velocity of the elastic wave, the thickness D of the wavenumber K of the elastic wave piezoelectric plate P _R Is zero, the phase velocity V _{kd = 0} of the elastic wave in the S ₀ mode when the product KD is zero
And the thickness D of each of the piezoelectric plates is approximately equal to or less than each of the electrode period lengths p, and the thickness of the non-piezoelectric plate is approximately equal to the thickness D of each of the piezoelectric plates or Above that, it is less than about 2.5 times the thickness D of each piezoelectric plate, and the phase velocity of the elastic wave propagating to the non-piezoelectric plate alone is the phase velocity of the elastic wave propagating to each piezoelectric plate alone. smaller than, the information processing unit is intermittently by sequentially predetermined cycle said switch W _i, detects the magnitude of the electric signal E _R, the plate surface of the side not having the display screen in the non-piezoelectric plate determined by the fact that the pen tip of the input pen on contacts at a pressure exceeding a predetermined value is the magnitude of the electrical signal E _R attenuated or abolished, the magnitude of the electrical signal E _R is attenuated or eliminated to identify the switch W _i, which has been sometimes connected The contact position is identified, and information corresponding to the identified contact position is displayed on the display screen. The ultrasonic touch panel according to claim 6, wherein x <1/2 at a shorter distance xp among the distance between the electrode finger of the electrode T _{i-1 and} the electrode finger of the electrode T _i-2. At the same time, the phase difference 2πy between said electric signal E _T1 and E _T2
In this case, x + y = ± 1/2 holds, and the electrode R _-1
At the shorter distance xp of the distance between the electrode finger of the electrode R- _{2 and} the electrode finger of the electrode R- ₂ , the phase difference between the electric signals E _R1 and E _R2 at the same time x <１ ／. At 2πy, x + y = ± 1/2 holds. Ultrasonic forth in claim 7, wherein the channel U _Xi (i = 1 of the acoustic wave between said two-layer structure L _Ti in ultrasonic transmitter means X the two-layer structure L _R, 2, ......, N) and the ultrasonic transmitter means propagation path of the acoustic wave between said two-layer structure L _Ti and the two-layer structure L _R in the Y U _Yi (i = 1,2,
.., N) are orthogonal to each other. In the ultrasonic touch panel according to claim 8, the propagation paths U _Xi are adjacent to each other or partially overlap each other, and the propagation paths U _Yi are adjacent to each other or partially overlap each other. The ultrasonic touch panel according to claim 9, wherein the oscillator H _i (i = 1, 2,...) Using the propagation paths U _Xi and U _Yi as delay elements.
..., have N) is configured, the input of the phase shifter S _T in ultrasonic transmitter unit X, the ultrasonic transmitting and receiving the phase shifter in the decoupling means Y S _R amplifier A _Y to the output terminal of the the are connected through said input end of said phase shifter S _T in ultrasonic transmitter unit Y is via the amplifier a _X in the phase shifter S output of _R in the ultrasonic transmitter means X are connected Te, signal loop of the oscillator H _i, the said phase shifter S _T in ultrasonic transmitter unit X, the switch W _i, the channel U _Xi, the phase shifter S _R, the amplifier A _X, and wherein the phase shifter S _T in ultrasonic transmitter unit Y, the switch W _i, the channel U _Yi, said phase shifter S _R, consists of the amplifier A _Y. In the ultrasonic touch panel according to the tenth aspect, each of the piezoelectric plates is made of a piezoelectric ceramic, and a direction of a polarization axis of the piezoelectric ceramic is parallel to a thickness direction of the piezoelectric ceramic. In the ultrasonic touch panel according to the eleventh aspect, each of the piezoelectric plates is made of PVDF or another piezoelectric polymer compound. In the ultrasonic touch panel according to the twelfth aspect, the non-piezoelectric plate is made of acrylic or another polymer compound. The ultrasonic touch panel according to claim 13, wherein the phase velocity of the elastic wave propagating to the display screen alone is:
The phase velocity is larger than the phase velocity of the elastic wave propagating through the non-piezoelectric plate alone.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic touch panel according to the present invention has a non-piezoelectric plate, at least two ultrasonic wave transmitting and receiving means X and Y, and at least one type of non-piezoelectric plate provided on one of the surfaces. It has a simple structure consisting of a display screen displayed in color and an information processing unit. The information processing section is connected to each ultrasonic wave transmitting / receiving means and a display screen. Two structures are provided as ultrasonic wave transmitting / receiving means. The first structure is that each ultrasonic transmitting / receiving means has N sets of interdigital electrodes I
_{Ti (i = 1,2, ......,} N) and the piezoelectric plate P _T with and a piezoelectric plate P _R having the interdigital electrodes I _R, N number of switches C
_i (i = 1, 2,..., N). In this case, the interdigital transducers I _Ti is provided on one plate surface of the piezoelectric plate P _T, the piezoelectric plate P _T is fixed to the non-piezoelectric plate via either one plate surface of the piezoelectric plate P _T I have. IDT I _R is provided on one plate surface of the piezoelectric plate P _R, the piezoelectric plate P _R is fixed via one plate surface either of the piezoelectric plate P _R to the non-piezoelectric plate. The output terminal of the switch C _i is connected to the input terminal of the interdigital electrodes I _Ti. The piezoelectric plate P _T is part P _Ti (i = 1,2 corresponding to the interdigital transducer I _Ti, ......,
N). Non piezoelectric plate includes a portion corresponding to the portion P _Ti, and a portion corresponding to the piezoelectric plate P _R. By adopting a structure for inputting substantially corresponding electrical signal E _T frequencies interdigital periodicity p of interdigital electrodes I _Ti in interdigital transducer I _Ti,
An elastic wave is excited to a two-layer structure part L _Ti (i = 1, 2,..., N) composed of a part P _Ti and a part corresponding to the part P _Ti of the non-piezoelectric plate, It can be propagated through the piezoelectric plate. The elastic wave excited in the two-layer structure part L _Ti is S ₀
The mode and the first-order or higher-order mode waves (that is, waves excluding the A ₀ mode), and the wavelength of this elastic wave is substantially equal to the electrode period length p of the interdigital transducer I _Ti . The phase velocity of this elastic wave is the phase velocity V _{kd = 0} of the elastic wave in the S ₀ mode when the product KD of the wave number K of the elastic wave and the thickness D of the piezoelectric plate _PT is zero.
Not only can the degree of conversion of the electric energy applied from the interdigital electrode I _Ti into an elastic wave be increased, but also the piezoelectric plate _PT and the non-piezoelectric plate Reflection and the like caused by acoustic impedance mismatch at the interface can be removed. The piezoelectric plate P _T of the thickness D of the interdigital electrodes I _Ti
Second electrode period length p and is about the same or less than, the thickness D of the piezoelectric plate P _T with the thickness of the non-piezoelectric plate to approximately the same or greater than the thickness D of the piezoelectric plate P _T. By adopting a structure of five times or less, it is possible to efficiently excite the S ₀ mode and the first-order or higher-order elastic waves in the two-layer structure part L _Ti . That is, the degree to which the electric energy applied from the interdigital electrode I _Ti is converted into an elastic wave can be increased. As a non-piezoelectric plate,
Phase velocity piezoelectric plate P _T of the elastic wave propagating in a non-piezoelectric plate alone
By using a material having a phase velocity smaller than the phase velocity of an elastic wave propagating to a single body, for example, an acrylic resin or other polymer compound, the elastic wave can be efficiently excited in the two-layer structure part L _Ti and propagated through the non-piezoelectric plate. Can be. In this way,
Low voltage driving with low power consumption is possible. Interdigital electrode I
By adopting a structure in which _Ti and I _R are arranged so that the directional axes of the transmission and reception of the elastic wave are common, the elastic wave propagated in the non-piezoelectric plate can be transmitted to the piezoelectric plate P _R and the piezoelectric plate among the non-piezoelectric plates. plate P _R to be propagated to the two-layer structure L _R consisting of the corresponding parts, a two-layer structure L IDT and an elastic wave propagating in the _R I _R
Can be converted into an electric signal E _R having a frequency substantially corresponding to the electrode cycle length p and output. In this case, the wavelength of the acoustic wave propagating in the two-layer structure L _R is approximately equal to the interdigital periodicity p of interdigital transducer I _R. Phase velocity of the acoustic wave, such as the product KD and the thickness D of the wave number K and the piezoelectric plate P _R of the acoustic wave is approximately equal to the phase velocity V _{kd = 0} in the acoustic wave S ₀ mode in the case of zero by adopting the structure, not only can the elastic waves propagated to the two-layer structure L _R is increased the degree that is converted to an electrical signal at the interdigital transducer I _R, the piezoelectric plate P _R and the non-piezoelectric plate Reflection or the like caused by acoustic impedance mismatch at the interface with the interface can be eliminated. Further, in substantially the same or less than the thickness D of the piezoelectric plate P _R and interdigital periodicity p of interdigital transducer I _R, the thickness of the non-piezoelectric plate to the thickness D of the piezoelectric plate P _R substantially the same as or by adopting the structure below 2.5 times the thickness D of the piezoelectric plate P _R as well as the more, propagating acoustic waves are propagated in a non-piezoelectric plate efficiently two-layer structure L _R after, it is possible to output from the interdigital transducer I _R as an electric signal E _R. That is, the degree to which the elastic wave is converted into the electric signal E _R can be increased. Further, as the non-piezoelectric plate, less material than the phase velocity of the acoustic wave phase velocity of the acoustic wave propagating in a non-piezoelectric plate alone is propagated on the piezoelectric plate P _R alone, for example, adopting an acrylic resin other polymer compounds Accordingly, it is possible to propagate the acoustic wave which is propagated in a non-piezoelectric plate efficiently two-layer structure L _R. If between the interdigital electrodes I _Ti and I _R on the plate surface of the side having no display screen in the non-piezoelectric board is contacted at a pressure exceeding a predetermined value to the pen tip of the input pen, the propagation of an acoustic wave Since the path is interrupted, the electric signal E _R output to the interdigital electrode I _R disappears or attenuates accordingly. The function of the information processing unit to detect the magnitude of the electric signal E _R , and the fact that the magnitude of the electric signal E _R attenuates or disappears when the tip of the pen touches the surface of the non-piezoelectric plate with a pressure exceeding a predetermined value In this case, it is detected that the non-piezoelectric plate has come into contact with the plate surface with a pressure exceeding a predetermined value. At this time, since the elastic wave propagates inside the non-piezoelectric plate instead of near the surface, the elastic wave disappears or attenuates by contacting either one of the two non-piezoelectric plates. I do. Therefore, a display screen can be provided on one of the plate surfaces, and the other plate surface can be used as a contact surface of the pen tip. Further, since the elastic wave does not disappear or attenuate even if the hand is touched lightly, it is possible to prevent a malfunction due to a hand on the non-piezoelectric plate or the like. In this way, it is not affected by light hand or small amount of foreign matter on the non-piezoelectric plate,
Moreover, the response time is short. Therefore, it is possible to realize a touch panel that has a response only when the input pen touches the non-piezoelectric plate with the pen tip or the like. Furthermore, the functions of the information processing unit is intermittently by sequentially predetermined cycle switch C _i, the electric signal E _R
By size of and a function of specifying the contact position on the non-piezoelectric plate by identifying the switch C _i which is connected when the attenuated or abolished, the contact position on the non-piezoelectric plate is seen. For example, the magnitude of the electric signal E _R disappears by touching the surface of the non-piezoelectric plate, and if the switch C ₅ is connected at that time, the elastic wave corresponding to the switch C ₅ is generated. It can be seen that the contact position is on the propagation path. Also, information from the fact that a function of displaying information corresponding to the switch C _i the information processing unit is identified on the display screen, by contacting a plate on surfaces of the non-piezoelectric plate, corresponding to the contact position Can be displayed on the display screen. The second structure of the ultrasonic wave transmitting / receiving means is such that each ultrasonic wave transmitting / receiving means has N sets of interdigital transducers T _i (i = 1, 2,...,
N) and N ground electrodes G _Ti (i = 1, 2,...,
A piezoelectric plate P _T having a N), 1 set of the piezoelectric plate P _R having the interdigital electrodes R and the ground electrode G _R, and the phase shifter S _T, the phase shifter S _R, N sets of switches W _i (i = 1, 2,...,
N). IDT T _i is provided on one plate surface of the piezoelectric plate P _T, the ground electrode G _Ti a piezoelectric plate P _T
The piezoelectric plate _PT is fixed to a non-piezoelectric plate via a ground electrode G _Ti . IDT R is provided on one plate surface of the piezoelectric plate P _R, the ground electrode G _R is provided on the other plate surface of the piezoelectric plate P _R, the piezoelectric plate P _R is through the ground electrode G _R To the non-piezoelectric plate. The piezoelectric plate P _T is the portion P corresponding to the IDT T _i
Ti (i = 1, 2,..., N). Non-piezoelectric plate is part P
Including a portion corresponding to _Ti, and a portion corresponding to the piezoelectric plate P _R. IDT T _i consists electrode T _i-1 and T _i-2, longer the distance between the electrode fingers of the electrode T _i-1 of the electrode finger and the electrode T _i-2 and short and There are two types. Switch W _i consists switches W _i-1 and the switch W _i-2, the output terminal of the switch W _i-1 is connected to an input end of the electrode T _i-1, the output terminal of the switch W _i-2 is It is connected to the input terminal of the electrode _Ti-2 . Phase shifter S _T at least one coil L ₁
Wherein the coil L ₁ is connected to the input end of the switch W _i-1 or W _i-2. IDT R consists electrode R _-1 and R _-2, there are two types of long and short the distance between the electrode fingers of the electrode finger and the electrode R _-2 electrode R _-1 . Phase shifter S _R comprises at least one coil L _2, the coil L ₂ is connected to an output end of the electrode R _-1 or R _-2. An electric signal E having a phase difference of 2πy between the electrode T _i-1 and the ground electrode G _Ti and between the electrode T _i-2 and the ground electrode G _Ti.
By inputting _T1 and E _T2 , a unidirectional elastic wave is excited in a two-layer structure part L _Ti composed of a part P _Ti and a part corresponding to the part P _Ti of the non-piezoelectric plate, and its elasticity is excited. Waves can propagate through the non-piezoelectric plate. Excitation of such a unidirectional elastic wave not only enables further low power consumption driving, but also enables the first ultrasonic wave transmitting / receiving means to be driven.
As seen in an ultrasonic touch panel with a structure of
There is no reflection of elastic waves generated at the two-layer structure part L _Ti or at the end of the non-piezoelectric plate. Therefore, the ultrasonic touch panel having the second structure of the ultrasonic wave transmitting / receiving means has a small number of unnecessary signals and high sensitivity. The frequency of the electrical signal E _T1 and E _T2 corresponds substantially to the interdigital periodicity p of IDT T _i. Here, at the shorter distance xp of the distance between the electrode finger of the electrode T _{i-1 and} the electrode finger of the electrode T _i-2 , x <１ ／ and the electric signals E _T1 and E _T2. In the case where x + y = ± 1/2 is satisfied in the phase difference 2πy between the two-layer structure portion L
_A unidirectional elastic wave is excited in _Ti . For example, if x is 1
At / 4, y = 1/4 or y = -3 / 4.
That is, the distance xp is p / 4, and the phase difference 2πy is π / 2.
By inputting the electric signals E _T1 and E _T2 of (90 °) or −3π / 2 (−270 °), it is possible to excite a unidirectional elastic wave to the two-layer structure part L _Ti. .
Acoustic wave excited in the two-layer structure L _Ti is a wave of S ₀ mode and first-order or higher-order mode, the wavelength of the elastic wave is approximately equal to the interdigital periodicity p of IDT T _i. Phase velocity of the acoustic wave, such as the product KD and the thickness D of the wave number K and the piezoelectric plate P _T of the acoustic wave is approximately equal to the phase velocity V _{kd = 0} in the acoustic wave S ₀ mode in the case of zero by adopting the structure, electrical energy applied from interdigital transducer T _i is not only able to increase the degree of being converted into an acoustic wave, the acoustic impedance at the interface between the piezoelectric plate P _T and non-piezoelectric plate Reflections and the like caused by mismatching of the two can be eliminated. Further, in substantially the same or less than the thickness D of the piezoelectric plate P _T and interdigital periodicity p of IDT T _i, the thickness of the non-piezoelectric plate to the thickness D of the piezoelectric plate P _T generally equal to or By adopting a structure in which the thickness is greater than 2.5 times the thickness D of the piezoelectric plate _PT , the elasticity of the S ₀ mode and the first or higher order mode can be efficiently provided in the two-layer structure part L _Ti. It becomes possible to excite the waves. That is, it is possible to increase the degree to which the electrical energy applied from interdigital transducer T _i is converted into acoustic waves. Further, by adopting a material in which the phase velocity of the elastic wave propagating through the non-piezoelectric plate alone is smaller than the phase velocity of the elastic wave propagating through the piezoelectric plate _PT alone, as the non-piezoelectric plate, the two-layer structure L
_An elastic wave can be efficiently excited in _Ti and propagated through the non-piezoelectric plate. In this way, low power consumption driving can be performed at a low voltage. In addition, the area of the non-piezoelectric plate can be relatively large. By the IDT T _i and R directional axes of transmission and reception waves of the elastic waves to adopt a structure arranged to be common, and the piezoelectric plate P _R acoustic wave which is propagated in a non-piezoelectric plate, non It is propagated to the two-layer structure L _R consisting of the portion corresponding to the piezoelectric plate P _R of the piezoelectric plate, part 2
Layer structure L the acoustic wave propagating in _R as an electric signal E _{R 1} and E _R2 having a phase difference 2πy the electrode R _-1 ground electrode G _R
Can be output from between the ground electrode G _R and between the electrodes R _-2 with. Phase shifter S _R electric signals E _R1 and E _R2
Can be combined with the electric signal E _R of the same phase and output. The frequencies of the electric signals E _R1 and E _R2 substantially correspond to the electrode period length p of the interdigital transducer R. Here, at the shorter distance xp of the distance between the electrode finger of the electrode R _{-1 and} the electrode finger of the electrode R _-2 , x <１ ／ and the electric signal E _R1 and E _R2 in the phase difference 2πy between, when x + y = ± 1/2 is satisfied, IDT R and the ground electrode G _R detects only unidirectional acoustic wave propagating in the two-layer structure L _R The electric signals E _R1 and E
Enable output as _R2 . For example, if x is 1
At / 4, y = 1/4 or y = -3 / 4.
That is, if the distance xp is p / 4, the phase difference 2πy becomes π
/ 2 (90 °) or -3π / 2 (-270 °) electrical signals E _R1 and E _R2 is the ground electrode G _R and between the electrodes R _-2 and the ground electrode G _R and the electrode R _-1 is Output from between. The wavelength of propagating a two-layer structure L _R acoustic wave is approximately equal to the electrode periodicity p of interdigital transducers R. At this time,
Phase velocity of the propagated acoustic wave to a two-layer structure L _R is the phase velocity of the S ₀ mode acoustic wave in the case of the product KD of the thickness D of the wave number K and the piezoelectric plate P _R of the acoustic wave is zero V by employing approximately equal such structures and _{kd = 0,} it is possible not only to acoustic waves propagating in the two-layer structure L _R is increased the degree that is converted into an electric signal in the IDT R,
Reflection or the like caused by acoustic impedance mismatch at the interface between the piezoelectric plate _PR and the non-piezoelectric plate can be eliminated. Further, in substantially the same or less than the thickness D of the piezoelectric plate P _R and interdigital periodicity p of interdigital electrodes R, the thickness of the non-piezoelectric plate to the thickness D of the piezoelectric plate P _R substantially equal to or is propagated by adopting a structure that than 2.5 times the thickness D of the piezoelectric plate P _R, an elastic wave is propagated in a non-piezoelectric plate efficiently two-layer structure L _R while above After
It is possible to output an electric signal from the interdigital electrode R. That is, the degree to which the elastic wave is converted into an electric signal can be increased. Furthermore, as a non-piezoelectric plate,
The phase velocity of the elastic wave propagating on the non-piezoelectric plate alone is equal to the piezoelectric plate P _R
By employing the smaller material than the phase velocity of the acoustic wave propagating in a single can of propagating acoustic waves are propagated in a non-piezoelectric plate efficiently two-layer structure L _R.
When the interdigital transducers T _i and R on the surface of the non-piezoelectric plate having no display screen are brought into contact with the pen tip of the input pen at a pressure exceeding a predetermined value, the propagation path of the elastic wave is reduced. Since it is cut off, the elastic wave disappears or attenuates. Accordingly, since also disappears or attenuates electrical signals output IDT R with it, also disappears or attenuates electrical signals E _R outputted from the phase shifter S _R. The function of the information processing unit to detect the magnitude of the electric signal E _R , and the fact that the magnitude of the electric signal E _R attenuates or disappears when the tip of the pen touches the surface of the non-piezoelectric plate with a pressure exceeding a predetermined value In this case, it is detected that the non-piezoelectric plate has come into contact with the plate surface with a pressure exceeding a predetermined value. On this occasion,
Since the elastic wave is a wave propagating inside the non-piezoelectric plate, not near the surface thereof, the elastic wave disappears or attenuates by contacting either of the two plate surfaces of the non-piezoelectric plate. Therefore, a display screen can be provided on one of the plate surfaces, and the other plate surface can be used as a contact surface of the pen tip. Further, since the elastic wave does not disappear or attenuate even if the hand is touched lightly, it is possible to prevent a malfunction due to a hand on the non-piezoelectric plate or the like. In this way, the response time is short without being affected by a light hand touch or a small amount of foreign matter adhering to the non-piezoelectric plate. Therefore, it is possible to realize a touch panel that has a response only when the input pen touches the non-piezoelectric plate with the pen tip or the like. Furthermore, the functions of the information processing unit is intermittently by sequentially predetermined cycle switches W _i, nonpiezoelectric board by the magnitude of the electric signal E _R to identify the switch W _i which is connected when the attenuated or abolished And a function for specifying the contact position of the non-piezoelectric plate. In this case, the switch _Wi-1 and the corresponding switch _Wi-2 are always in the same state. For example, the switch W _4-2 if the switch W _4-1 is connected are also connected, the switch W _4-1 is intermittently also switch W _4-2 if intermittently. In this way, for example, the magnitude of the electric signal E _R disappears by contacting the surface of the non-piezoelectric plate, and if the switch W ₃ is connected at that time, the switch W ₃ is connected to the switch W ₃ . It can be seen that the corresponding acoustic wave propagation path is the contact position. Also, information from the fact that a function of displaying information corresponding to the switch W _i which the information processing unit is identified on the display screen, by contacting a plate on surfaces of the non-piezoelectric plate, corresponding to the contact position Can be displayed on the display screen. In addition, the ultrasonic touch panel of the present invention, which can excite an elastic wave having one direction, can be driven with even lower power consumption, has less unnecessary signals, and has high sensitivity. The ultrasonic touch panel of the present invention has at least two ultrasonic transmitting and receiving means X and Y. The propagation path U _Xi (i = 1, 2,..., N) of the elastic wave between the two-layer structure part L _Ti and the two-layer structure part L _R in the ultrasonic wave transmitting and receiving means X, and the ultrasonic wave transmitting and receiving means Two-layer structure part L _Ti and two-layer structure part L in Y
Propagation path of the acoustic wave between the _{R U Yi (i = 1,2,} ......,
N) and a structure that is orthogonal to each other,
When the pen tip of the input pen contacts the surface of the non-piezoelectric plate that does not have a display screen with a pressure exceeding a predetermined value, the coordinates of the contact position are output as electric signals output from each ultrasonic wave transmitting / receiving means. It can be specified from the magnitude of E _R.
That is, the coordinates of the contact position are made to correspond to two-dimensional coordinates with the propagation paths U _Xi and U _Yi as the X axis and the Y axis, respectively.
If the contact position is made to correspond to the intersection of the propagation paths U _Xi and U _Yi , the coordinates of the intersection are calculated. In addition, the propagation path U _Xi
The contact position on the non-piezoelectric plate can be specified more precisely by adopting a structure in which the transmission paths U _Yi are adjacent to or partially overlap with each other and the propagation paths U _Yi are mutually adjacent or partially overlapped. Becomes
In the ultrasonic touch panel having a first structure of the ultrasonic transmitter means, while connecting one of the switches C _i in the X-axis direction, a method is employed to cycle the switch C _i in the Y-axis direction is, in the ultrasonic touch panel having a second structure of the ultrasonic transmitter means, methods while connected to a pair of switches W _i in the X-axis direction, a round switch W _i in the Y-axis direction Has been adopted. Thus, for example, the propagation path U _X3 between the interdigital transducer T ₃ and the interdigital transducer R in the X-axis direction, and the propagation path between the interdigital transducer T ₅ and the interdigital transducer R in the Y-axis direction. If the intersection with U _Y5 is touched with the pen tip, the magnitude of the electric signal E _{R in} the X-axis direction is attenuated or eliminated only when the switch W ₃ in the X-axis direction is connected, and at the same time, the switch in the Y-axis direction is made. only when connecting the W ₅ magnitude of the electrical signal E _R in the Y-axis direction is attenuated or disappears. Thus, it is found that the intersection of the propagation paths U _X3 and U _Y5 is in contact. In the ultrasonic touch panel having a first structure of the ultrasonic transmitter means, respectively the switch C _i in ultrasonic transmitter means X and Y and the switch C _Xi and switch C _Yi, ultrasonic transmitting and receiving an input end of the switch C _Xi connected via an amplifier a _Y to the output terminal of the interdigital electrodes I _R in the wave means Y, via an amplifier a _X input terminal of the switch C _Yi at the output end of the interdigital transducer I _R in ultrasonic transmitter means X By adopting a structure in which the propagation paths U _Xi and U _Yi are used as delay elements, it is possible to configure an oscillator H _i (i = 1, 2,..., N). At this time, the signal loop of the oscillator H _i switch C
_Xi , propagation path U _Xi , amplifier A _X , switch C _Yi , propagation path U
_Yi and amplifier _AY . Since the circuit configuration is simplified in this way, the device can be further reduced in size and weight, and can be driven with low power consumption and low voltage. In the ultrasonic touch panel having a second structure of the ultrasonic transmitter means, the phase shifter in the ultrasonic transmitter means X S _T, switches W _i and the phase shifter S _R each phase shifter S _T
X, switch W and _Xi and the phase shifter S _RX, the phase shifter in the ultrasonic transmitter means Y S _T, switches W _i and the phase shifter S
_R is a phase shifter S _TY , a switch W _Yi and a phase shifter S
And _RY, and connected via amplifier A _Y to the output terminal of the phase shifter S _RY input terminal of the phase shifter S _TX, amplifier A the inputs of the phase shifter S _TY to the output terminal of the phase shifter S _RX By adopting the structure of connection via _X , it is possible to configure an oscillator _Hi (i = 1, 2,..., N) using the propagation paths U _Xi and U _Yi as delay elements. In this case, the oscillator H _i signal loops phase shifter S _TX, the switch W _Xi, channel U _Xi, phase shifter S _RX, amplifier A _X, phase shifter S _TY, switches W _Yi, channel U _Yi, It comprises a phase shifter _SRY and an amplifier _AY . In this way,
The simplification of the circuit configuration further promotes the reduction in size and weight of the device, and enables driving at low voltage with low power consumption. In the ultrasonic touch panel of the present invention, the piezoelectric plate P
_{By using} a piezoelectric ceramic as _T and adopting a structure in which the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction, elastic waves can be efficiently excited in the two-layer structure part L _Ti and the non-piezoelectric plate Can be propagated to Moreover, the piezoelectric ceramic is employed as the piezoelectric plate P _R, by adopting a structure for collimating the direction and the thickness direction of the polarization axis of the piezoelectric ceramic, the acoustic wave propagated in a non-piezoelectric plate efficiently it can be propagated to the two-layer structure L _R. In the ultrasonic touch panel of the present invention, PVD is used as the piezoelectric plate _PT.
By adopting F and other polymer piezoelectric films,
An elastic wave can be efficiently excited in the two-layer structure part L _Ti and propagated through the non-piezoelectric plate. In addition, PV as a piezoelectric plate P _R
DF by adopting other polymeric piezoelectric film, can be propagated acoustic wave propagated in a non-piezoelectric plate efficiently two-layer structure L _R. In the ultrasonic touch panel of the present invention, as the display screen, by using a substance in which the phase velocity of the elastic wave propagating to the display screen alone is larger than the phase velocity of the elastic wave propagating to the non-piezoelectric plate alone, Of the elastic wave transmitted to the display screen itself can be suppressed.

FIG. 1 is a sectional view showing a first embodiment of an ultrasonic touch panel according to the present invention. In this embodiment, an acrylic plate 1 is used.
It comprises a display screen 2, a driving section 3, a frame 4, an ultrasonic wave transmitting / receiving means X in the X-axis direction, and an ultrasonic wave transmitting / receiving means Y in the Y-axis direction. The ultrasonic wave transmitting / receiving means X is an interdigital transducer T _Xi (i =
1, 2,..., 8), interdigital electrodes R _X , ground electrodes G _{T Xi}
(I = 1, 2,..., 8), ground electrode G _RX , phase shifters S _TX , S _RX , amplifier A _X , switch W _Xi (i = 1, 2, 2)
.., 8), composed of piezoelectric ceramic plates P _TX and P _RX . The ultrasonic wave transmitting / receiving means Y includes an interdigital electrode T _Yi (i = 1, 2,...)
.., 8), interdigital electrodes R _Y , ground electrodes G _TYi (i = 1,
, 8), ground electrode G _RY , phase shifters S _TY , S _RY , amplifier A _Y , switch W _Yi (i = 1, 2,..., 8), piezoelectric ceramic plates P _TY and P _RY Consists of In FIG. 1, only the acrylic plate 1, the display screen 2, the drive unit 3, the frame 4, and the ultrasonic wave transmitting / receiving means X are illustrated. IDTs T _Xi , T
_Yi, R _X and R _Y are made of aluminum thin film. Each piezoelectric ceramic plate is made of TDK 101A material (product name) with a thickness of 400 μm
Consists of The acrylic plate 1 is made of an acrylic resin having a thickness of 1 mm. Each piezoelectric ceramic plate is fixed to an end of one surface of the acrylic plate 1 with an epoxy resin having a thickness of about 20 μm. The velocity of the transverse wave of the elastic wave propagating through each piezoelectric ceramic plate alone is 2450 m / s, and the velocity of the longitudinal wave is 4390 m / s. The speed of the shear wave propagating through the acrylic plate 1 alone is 1461 m / s, and the speed of the longitudinal wave is 2718 m / s.
In this case, each of the shear wave velocity and the longitudinal wave velocity of the elastic wave propagating through each piezoelectric ceramic plate alone is approximately 0.6 times. IDTs T _Xi , T _Yi , R _X and R _Y are provided on piezoelectric ceramic plates P _TX , P _TY , P _RX and P _RY , respectively. The display screen 2 is in contact with the central portion of the surface of the acrylic plate 1 having the piezoelectric ceramic plates. Each ground electrode is provided at the interface between each piezoelectric ceramic plate and the acrylic plate 1, and the ground electrodes G _TXi , G _RX , G _TYi and G _RY are interdigital electrodes T _Xi , R _X , T _{Y i} and R, respectively. It is provided in the part corresponding to _Y. The piezoelectric ceramic plate P _TX includes a portion P _TXi (i = 1, 2,..., 8) corresponding to the interdigital electrode T _Xi , and the piezoelectric ceramic plate P _TYi includes a portion P corresponding to the interdigital electrode T _Yi.
TYi (i = 1, 2,..., 8). The acrylic plate 1 has a portion corresponding to the portion P _TXi , a portion corresponding to the portion P _{T Yi} ,
A portion corresponding to the piezoelectric ceramic plate P _RX and a portion corresponding to the piezoelectric ceramic plate P _RY are included. The part corresponding to the part P _TXi of the part P _TXi and the acrylic plate 1 is a two-layer structure part L _TXi (i =
, 8), and a portion of the piezoelectric ceramic plate P _RX and the acrylic plate 1 corresponding to the piezoelectric ceramic plate P _RX forms a two-layer structure portion L _RX . Part P _TYi and acrylic plate 1
A portion corresponding to the portion P _Tyi two-layer structure L _Tyi (i
= 1, 2,..., 8), and the portion of the piezoelectric ceramic plate P _RY and the acrylic plate 1 corresponding to the piezoelectric ceramic plate P _RY is 2
The layer structure _LRY is formed. The outer edge of the plate surface (hereinafter referred to as a panel screen) of the acrylic plate 1 that does not have each piezoelectric ceramic plate is fixed to the frame 4 and is surrounded.
The frame 4 prevents intrusion of drinks such as tea and foods such as mayonnaise on the panel screen of the acrylic plate 1 even if they adhere thereto. Accordingly, internal components such as the piezoelectric ceramic plate and the drive circuit are shielded from the outside and protected. FIG.
FIG. 2 is a plan view showing the interdigital transducer T _Xi of FIG. 1. The interdigital transducer T _Yi has the same structure as the interdigital transducer T _Xi .
IDT R _X and R _Y have the same structure except that the interdigital transducer T _Xi number of the electrode fingers is different.
The interdigital transducer T _Xi has ten pairs of electrode fingers, the electrode cycle length p is 460 μm, and the overall shape is a parallelogram. Interdigital transducer T _Xi consists electrodes T _Xi-1 and T _Xi-2, interdigital electrodes T _Yi consists electrodes T _Yi-1 and T _Yi-2, interdigital electrodes R _X electrode R _X-1 and Consists of R _X-2 , and the interdigital electrode R _Y consists of electrodes R _Y-1 and R _Y-2 . In each interdigital electrode, there are two types of distance between the electrode fingers, and the shorter distance xp is 115 μm. At this time, x is 1
/ 4. FIG. 3 is a partial perspective view of the ultrasonic touch panel of FIG. The interdigital transducer T _Xi and the ground electrode G _TXi are connected to a phase shifter S _TX via a switch W _Xi , and the interdigital transducer T _Yi and the ground electrode G _TYi are connected to a phase shifter S via a switch W _Yi.
Connected to _Tyi, IDT R _X and the ground electrode G _RX is connected to the phase shifter S _RX, interdigital transducers R _Y and the ground electrode G _RY is connected to the phase shifter S _RY. Phase shifter S _TX and S _TY includes coil L ₁ respectively, each comprise phase shifters S _RX and S _RY is a coil L _2. In FIG. 3, the interdigital transducer T _X1
And a state where the ground electrode G _TX1 is connected to the phase shifter S _TX , and the switch W _X1 is omitted. FIG. 4 is a plan view of the ultrasonic touch panel of FIG.
In FIG. 4, the acrylic plate 1, the piezoelectric ceramic plates P _TX , P _TY , P _RX ,
Only P _RY and IDTs T _Xi , T _Yi , R _X and R _Y are shown. FIG. 5 is a diagram showing a drive circuit of the ultrasonic touch panel of FIG. The drive unit 3 includes a voltage doubler rectifier 5, a comparator 6, and an information processing unit 7. The switch W _Xi is composed of a switch W _Xi-1 and a switch W _Xi-2 , the output terminal of the switch W _Xi-1 is connected to the input terminal of the electrode T _Xi-1 , and the output terminal of the switch W _Xi-2 is It is connected to the input terminal of the electrode T _Xi-2 . The switch W _Yi includes a switch W _Yi-1 and a switch W _Yi-2 , an output terminal of the switch W _Yi-1 is connected to an input terminal of the electrode T _Yi-1 , and an output terminal of the switch W _{Yi -2} is It is connected to the input terminal of the electrode T _Yi-2 . However, in FIG. 5, the connection between the information processing section 7 and the switch W _Xi and the connection between the information processing section 7 and the switch W _Yi are omitted. In the driving circuit of FIG. 5, electrodes T _Xi-1 electrical signal phase difference is 90 ° or -270 ° to and between the electrode T _{XI- 2} and the ground electrode G _TXi the ground electrode G _TXi E _T1 and When E _T2 is input via the phase shifter S _TX , only the electric signal of the center frequency indicated by the interdigital transducer T _Xi and the electric signal of a frequency in the vicinity of the center frequency of the electric signals E _T1 and E _T2 has a unidirectional elasticity. _Is converted into a wave and propagates through the two-layer structure part L _TXi ,
Further, the elastic wave propagates through the acrylic plate 1. Acoustic wave propagated in the acrylic plate 1 is propagated to the two-layer structure L _RX, center frequency and frequency in the vicinity indicated by interdigital electrodes R _X of the elastic waves propagated to the two-layer structure L _RX Is converted into electric signals E _R1 and E _R2 having a phase difference of 90 ° or −270 °, and between the electrode R _X-1 and the ground electrode G _{R X} and between the electrode R _X-2 and the ground electrode. Output from between G _RX . Electrical signals E _R1 and E _R2 output is output as a single electrical signal E _R of the retardation by passing through the phase shifter S _RX is zero, is amplified by an amplifier A _X. A part of the amplified electric signal is input between the interdigital transducer T _Yi and the ground electrode G _TYi via the phase shifter S _TY and the switch W _Yi , and the remainder via the voltage doubler rectifier 5 and the comparator 6. And sent to the information processing section 7. When an electric signal is input between the interdigital electrode T _Yi and the ground electrode G _TYi , the electric signal is transmitted in the same manner as in the X-axis direction.
Two electric signals E _T1 and E _T2 having different phases between _Yi-1 and the ground electrode G _TYi and between the electrode T _Yi-2 and the ground electrode G _TYi are inputted to the elastic wave having one direction. It is converted and propagates through the two-layer structure part _LTYi . Further the elastic wave is propagated in the two-layer structure L _RY through the middle acrylic plate 1, and between the electrodes R _Y-2 of the electrode R _Y-1 and the ground electrode G _RY and the ground electrode G _{RY Are} converted into electric signals E _R1 and E _R2 and output as a single electric signal E _R having a zero phase difference via a phase shifter S _RY , and amplified by an amplifier _AY . A part of the amplified electric signal is supplied to a phase shifter S _TX
The _signal is input between the interdigital transducer T _Xi and the ground electrode G _TXi via the switch W _Xi , and the remainder is sent to the information processing unit 7 via the voltage doubler rectifier 5 and the comparator 6.
The information processing section 7 has the following functions. First, switch W
To intermittently _Xi and W _Yi sequentially at a predetermined period, the second, detecting the magnitude of the electrical signal E _R, the third, the input pen on the panel screen of the acrylic plate 1 nib predetermined The contact at a pressure exceeding the value is determined by the magnitude of the electric signal E _R attenuating or disappearing. Fourth, the switch W connected when the magnitude of the electric signal E _R attenuates or disappears. Fifth, specifying the contact position by specifying _Xi and W _Yi , and displaying the information corresponding to the specified contact position on the display screen 2. When the switches W _Xi and W _Yi are sequentially turned on and off at a predetermined cycle, a method is adopted in which the switch W _Yi is cycled while one set of the switches W _Xi is connected. Further, the switch W _Xi-1 and the corresponding switch W _Xi-2 are always in the same intermittent state, and the switch W _Yi-1 and the corresponding switch W _Yi-2 are always in the same intermittent state. Elastic wave propagation path U between two-layer structure part L _TXi and two-layer structure part L _RX
Xi (i = 1, 2,..., 8) and the two-layer structure parts L _TYi and 2
Channel U _Yi (i = 1 of the acoustic wave between the layer structure L _RY,
,..., 8) with the pen tip, for example, when the intersection of the propagation paths U _X3 and U _Y5 is contacted,
At the same time the size of the X-axis direction of the electric signal E _R only when connecting the switch W _X3 is attenuated or disappears, only when connecting switches W _Y5 magnitude of the Y-axis direction of the electric signal E _R is attenuated or Disappear. Thus, the propagation path U
It turns out that the intersection of _X3 and _UY5 is in contact. That is, it is possible to specify the contact position by specifying the switches W _Xi and W _Yi that were connected when the magnitude of the electric signal E _R was attenuated or extinguished. As shown in FIG. 2, since the interdigital transducers form a parallelogram, the propagation paths U _Xi can be adjacent to each other without any gap, and the propagation paths U _Yi can be similarly spaced from each other. And adjacent structures can be adopted. Therefore, when specifying the contact position, all of the panel screens of the acrylic plate 1 can be used without gaps, so that the contact position can be specified precisely. If the propagation paths U _Xi partially overlap each other, two adjacent propagation paths U _Xi having the overlapped part are specified, so that the contact position is determined by the two propagation paths U _Xi. Is determined to be between the two. The same applies to the case where the propagation paths U _Yi partially overlap each other. In the driving circuit of FIG. 5, the input terminal of the phase shifter S _TX is connected to the phase shifter S output of _RY via amplifier A _Y,
By input of the phase shifter S _TY is connected to the output terminal of the phase shifter S _RX via the amplifier A _X, oscillator H _{i (i} = 1,
2,..., 8). The signal loop of the oscillator H _i includes a phase shifter S _TX , a switch W _Xi , a propagation path U _Xi , a phase shifter S _RX , an amplifier A _X , a phase shifter S _TY , a switch W _Yi , a propagation path U _Yi , and a phase shift. It consists of a device _SRY and an amplifier _AY . Since the circuit configuration is simplified in this way, the device can be further reduced in size and weight, and can be driven with low power consumption and low voltage. Figure 6 is a characteristic diagram showing the velocity dispersion curve of the acoustic wave propagating piezoelectric ceramic plate P _TX alone of each mode to the product (KD) between the thickness D of the wave number K and the piezoelectric ceramic plate P _TX acoustic wave It is a figure showing a phase velocity. FIG. 7 shows FIG.
FIG. 10 is a characteristic diagram showing a velocity dispersion curve of an elastic wave propagating through the two-layer structure part L _TXi of FIG. 8 characteristic diagram showing the relationship between the electromechanical coupling coefficient K ² and the KD value calculated from the phase velocity difference between the two electrical boundary conditions of different piezoelectric ceramic plate P _TX in a two-layer structure L _TXi of FIG It is. However, Figure 8 shows a characteristic diagram of the S ₂ mode. S is a two-layer structure L _TXi of FIG ₀
It has been confirmed that the mode and the first-order (A ₁ and S ₁ ) or higher order elastic waves are efficiently excited. S
The ₂ mode, K ² when KD value of about 1.4 indicates about 6.4% of the maximum value. That is, it is understood that the electric energy applied to the interdigital electrode T _Xi or T _Yi is most easily converted into the S ₂ mode elastic wave when the KD value is about 1.4. It is clear that the K ² value deserves evaluation even when compared with a value of about 5% of a LiNbO ₃ single crystal in a practical range as a piezoelectric substrate for a surface acoustic wave. 7 and 8, the phase velocity at which K ² has the maximum value depends on the wave number K of the elastic wave and the piezoelectric ceramic plate P _TX
It can be understood that the phase velocity V _{kd = 0} of the elastic wave in the S ₀ mode when the product KD with the thickness D is zero. FIG. 9 shows FIG.
_Of the piezoelectric ceramic plate P _TX in the two-layer structure L _TXi
One of which is a characteristic diagram showing the relationship between the electromechanical coupling coefficient K ² and the KD value calculated from the phase difference in speed electric boundary conditions. However, Figure 9 shows a characteristic diagram of the S ₄ mode.
K ² when KD value of about 2.1 indicates about 7.0% of the maximum value. In other words, it is seen that the electrical energy applied to the interdigital transducer T _{X i} or T _Yi is likely the most converted into acoustic waves S ₄ mode is when KD value of about 2.1. The phase velocity at which K ² has the maximum value is the phase velocity V
_It is almost equal to _{kd = 0} . FIG. 10 shows the electromechanical coupling coefficients K ² and K calculated from the phase velocity difference under two different electrical boundary conditions of the piezoelectric ceramic plate P _TX in the two-layer structure part L _TXi of FIG.
FIG. 4 is a characteristic diagram showing a relationship with a D value. However, FIG. 10 A ₅
FIG. 3 shows a characteristic diagram for a mode. K ² when KD value of about 2.6 indicates about 7.6% of the maximum value. In other words, it is seen that the electrical energy applied to the interdigital transducer T _Xi or T _Yi is likely the most converted into acoustic waves A ₅ mode is when KD value of about 2.6. Further, the phase velocity at which K ² has the maximum value is substantially equal to the phase velocity V _{kd = 0} . Figure 11 is the maximum value KD value in the vicinity of K ² in FIG. 10 (2.
It is a characteristic view which shows the displacement distribution in 6). The vertical axis shows the depth of the two-layer structure L _TXi in normalized value, interface depth of the piezoelectric ceramic plate P _TX and acrylic plate 1 corresponds to the case of zero. The abscissa shows the displacement as a normalized value. It can be seen that the acoustic wave of A ₅ mode to efficiently propagate inside of the acrylic plate 1. FIG. 12 is a sectional view showing a second embodiment of the ultrasonic touch panel of the present invention. This embodiment has the same structure as the first embodiment of FIG. 1 except for the ultrasonic wave transmitting / receiving means X and the ultrasonic wave transmitting / receiving means Y. In this embodiment, the ultrasonic wave transmitting / receiving means X is provided with interdigital electrodes I _{TX i} (i =
1, 2,..., 8), interdigital electrodes I _RX , amplifiers A _X ,
Switch C _Xi (i = 1, 2,..., 8), piezoelectric ceramic plate P
_TX and P _RX , and the ultrasonic wave transmitting / receiving means Y has an interdigital electrode I _TYi (i = 1, 2,..., 8) and an interdigital electrode I
_RY , amplifier A _Y , switch C _Yi (i = 1, 2,...,
8), consisting of piezoelectric ceramic plates _PTY and _PRY . FIG. 16 shows only the acrylic plate 1, the display screen 2, the frame 4, the voltage doubler rectifier 5, the comparator 6, the information processing unit 7, and the ultrasonic wave transmitting / receiving means X. The display screen 2 is in contact with the acrylic plate 1 as in FIG. The interdigital electrodes I _TXi , I _TYi , I _RX and I _RY are made of an aluminum thin film and are provided on the piezoelectric ceramic plates P _TX , P _TY , P _RX and P _RY respectively. Each piezoelectric ceramic plate is fixed on the acrylic plate 1 with an epoxy resin having a thickness of about 20 μm via each interdigital electrode. Piezoelectric ceramic plate P _TX part P _TXi (i = 1,2 corresponding to interdigital transducer I _TXi, ......,
8), and the piezoelectric ceramic plate P _TYi is composed of portions P _TYi (i = 1, 2,..., 8) corresponding to the interdigital electrodes I _TYi . Acrylic plate 1 has a portion portion corresponding to the P _TXi, parts corresponding to the parts P _Tyi, parts corresponding to the parts and the piezoelectric ceramic plate P _RY corresponding to the piezoelectric ceramic plate P _RX. A portion corresponding to the portion P _TXi of the portion P _TXi and the acrylic plate 1 _{forms a} two-layer structure portion L _TXi (i = 1, 2,..., 8), and the portion of the piezoelectric ceramic plate P _RX and the acrylic plate 1 The portion corresponding to the piezoelectric ceramic plate P _RX forms a two-layer structure L _RX . The portion corresponding to the portion P _TYi of the portion P _TYi and the acrylic plate 1 _{forms a} two-layer structure portion L _TYi (i = 1, 2,..., 8), and the portion of the piezoelectric ceramic plate P _RY and the acrylic plate 1 The portion corresponding to the piezoelectric ceramic plate P _RY forms a two-layer structure _LRY . FIG. 13 is a plan view showing the interdigital transducer I _TXi of FIG. The interdigital electrodes I _TXi and I _TYi have the same structure, and the interdigital electrodes I _RX and I _RY have the same structure except that the number of electrode fingers is different from that of the interdigital electrode I _TXi . The interdigital electrodes I _TXi are of a regular type having ten pairs of electrode fingers, the electrode cycle length p is 460 μm, and the overall shape is a parallelogram. In the interdigital electrode I _TXi , the distance between the electrode fingers is all uniform. The structure of the interdigital transducer I _TXi is the same as that of the interdigital transducer T _{Xi of} FIG. 2 except for the distance between the electrode fingers.
Is the same as FIG. 14 is a diagram showing a drive circuit of the ultrasonic touch panel of FIG. The outputs of switches C _Xi and C _Yi are connected to the inputs of _IDTs I _TXi and I _TYi , respectively. In FIG. 14, the connection between the information processing unit 7 and the switch C _Xi and the connection between the information processing unit 7 and the switch C _Yi are omitted. In the driving circuit of FIG. 14, when an electrical signal is inputted E _T from the interdigital transducer I _TXi,
Of the frequency of the electric signal E _T , only the electric signal of the center frequency indicated by the interdigital electrode I _{TXi and} the frequency in the vicinity thereof are converted into elastic waves, propagate through the two-layer structure L _TXi , and further _pass through the acrylic plate 1. Propagate. Acoustic wave propagated in the acrylic plate 1 is propagated to the two-layer structure L _RX, center frequency and frequency in the vicinity indicated by interdigital electrodes I _RX of the elastic waves propagated to the two-layer structure L _RX Is converted into an electric signal E _R and output from the interdigital transducer I _RX . The electric signal E _R is amplified by the amplifier A _X , and a part of the amplified electric signal is transmitted through the switch C _Yi to the interdigital electrode I
_The remainder is input to _TYi , and the remainder is sent to the information processing unit 7 via the voltage doubler rectifier 5 and the comparator 6. When an electric signal is input to the interdigital electrode _ITYi , the electric signal is converted into an elastic wave as in the case of the X-axis direction, and propagates through the two-layer structure _LTYi . In addition, the elastic wave is the acrylic plate 1
The light propagates through the inside to the two-layer structure _LRY , is output as an electric signal, and is amplified by the amplifier _AY . A part of the amplified electric signal is input to the interdigital electrode I _TXi via the switch C _Xi , and the remainder is sent to the information processing unit 7 via the voltage doubler rectifier 5 and the comparator 6. The information processing section 7 has the same function as the information processing section 7 in FIG. In this way, the switches C _Xi and C _Yi connected when the magnitude of the electric signal E _R is attenuated or extinguished.
By specifying, it is possible to specify the contact position. The input terminal of the switch C _Xi is connected to the interdigital electrode I.
Connected to the output terminal of _RY via the amplifier A _Y and the switch C
Input of _Yi is connected through an amplifier A _X to the output end of the interdigital electrodes I _RX. Thus, the oscillator H _i (i = 1, 2,...) Using the propagation paths U _Xi and U _Yi as delay elements
.., N). At this time, the signal loop of the oscillator H _i consists of the switch C _Xi, channel U _Xi, amplifier A _X, the switch C _Yi, channel U _Yi and amplifier A _Y. Therefore, since the circuit configuration is simplified, the reduction in size and weight of the device is further promoted, and driving at low voltage with low power consumption becomes possible. In the second embodiment of FIG. 12, each interdigital electrode has a structure provided at the interface between each piezoelectric ceramic plate and the acrylic plate 1, but each interdigital electrode is provided on the air side plate surface of each piezoelectric ceramic plate. A similar effect was observed in the structure thus obtained. When the first embodiment of FIG. 1 is compared with the second embodiment of FIG. 12, the unidirectional elastic wave excitation according to the first embodiment enables further lower power consumption driving. Moreover, in the first embodiment, since there is no reflection (which occurs at the two-layer structure portions L _TXi , L _TYi and the end of the acrylic plate 1) as seen in the second embodiment, unnecessary signals are reduced. And higher sensitivity. FIG. 15 is a sectional view showing a third embodiment of the ultrasonic touch panel of the present invention. In this embodiment, the acrylic plate 1 in the first embodiment of FIG. 1 is replaced with an acrylic plate 8. In FIG. 15, the piezoelectric ceramic plates P _TX , P
Only _RX , interdigital electrodes T _Xi , R _X , ground electrodes G _TXi , G _RX , frame 4 and acrylic plate 8 are shown. The acrylic plate 8 has a thickness of 400 μm and is made of the same material as the acrylic plate 1. The display screen 2 has an acrylic plate 8 in the same manner as in FIG.
Is in contact with The third embodiment of FIG. 15 is driven in the same manner as the first embodiment of FIG. 1, and has the same effect. FIG.
FIG. 16 is a characteristic diagram showing a velocity dispersion curve of an elastic wave propagating through the two-layer structure portion L _TXi in FIG. 15, and is a diagram showing a phase velocity of each mode with respect to a KD value. FIG. 17 is a characteristic diagram showing the relationship between the K ² value and the KD value calculated from the phase velocity difference under two different electrical boundary conditions of the piezoelectric ceramic plate P _TX in the two-layer structure portion L _TXi of FIG. . However, Figure 17 shows a characteristic diagram of the S ₁ mode. When the KD value is close to 1.8, K ² indicates about 7.6% of the maximum value. In other words, it is seen that the electrical energy applied to the interdigital transducer T _Xi is easily the most converted into acoustic waves S ₁ mode is when KD value is 1.8 neighborhood. Also, from FIGS. 16 and 17,
It can be seen that the phase velocity at which K ² has the maximum value is almost equal to the phase velocity V _{kd = 0} . FIG. 18 shows the two-layer structure L of FIG.
FIG. 11 is a characteristic diagram showing a relationship between a K ² value and a KD value calculated from a phase velocity difference under two different electrical boundary conditions of the piezoelectric ceramic plate P _TX in _TXi . However, Figure 18 shows a characteristic diagram of the A ₃ mode. When the KD value is about 3.1, K ²
Indicates about 7.5% of the maximum value. That is, the interdigital electrode T
It can be seen the electrical energy applied to the _Xi is easy to be most converted into acoustic waves A ₃ mode is when KD value of about 3.1. Further, the phase velocity at which K ² has the maximum value is substantially equal to the phase velocity V _{kd = 0} . FIG. 19 is a sectional view showing a fourth embodiment of the ultrasonic touch panel of the present invention.
In this embodiment, the acrylic plate 1 in the second embodiment shown in FIG.
Is replaced with an acrylic plate 8. In FIG. 19, only the piezoelectric ceramic plates P _TX and P _RX , the interdigital electrodes I _TXi and I _RX , the frame 4 and the acrylic plate 8 are illustrated. The display screen 2 is in contact with the acrylic plate 8 as in FIG. The fourth embodiment of FIG. 19 is driven in the same manner as the second embodiment of FIG. 12, and has the same effect. When the third embodiment in FIG. 15 is compared with the fourth embodiment in FIG. 19, the excitation of the unidirectional elastic wave according to the third embodiment enables further lower power consumption driving. Moreover, in the third embodiment,
Reflection as seen in the fourth embodiment (two-layer structure L _{TX i,} generated at the end portion of the L _Tyi and acrylic plate 8.)
Since there is no signal, unnecessary signals are reduced and the sensitivity is higher.

In the ultrasonic touch panel of the present invention according to the present invention, the piezoelectric plate P and the partial P _Ti in _T, non-piezoelectric S ₀ mode and a two-layer structure L _Ti comprising a portion corresponding to the portion P _Ti of plate 1 It is possible to excite an elastic wave of a higher order mode or higher and propagate the elastic wave through the non-piezoelectric plate. The phase velocity of the elastic wave is determined by the wave number K of the elastic wave and the thickness D of the piezoelectric plate _PT.
By employing approximately equal such structures and phase velocity V _{kd = 0} in the acoustic wave S ₀ mode in the case of the product KD is zero and, interdigital electrodes I _Ti or T _i (hereinafter, input interdigital In addition to increasing the degree of conversion of the electrical energy applied from the electrode to an elastic wave, the reflection caused by acoustic impedance mismatch at the interface between the piezoelectric plate _PT and the non-piezoelectric plate, etc. Can be removed. In the ultrasonic touch panel of the present invention, the acoustic wave S ₀ mode and first-order or higher order modes which are propagated in a non-piezoelectric plate and the piezoelectric plate P _R, corresponding to the piezoelectric plate P _R of the non-piezoelectric plate It is propagated to the two-layer structure L _R consisting of a partial, 2
The acoustic wave propagated in the layer structure L _R interdigital transducer I _R or R (hereinafter, referred to as an output IDT) from can be output as an electric signal. In this case, the phase velocity of the acoustic wave, the phase velocity of the S ₀ mode acoustic wave in the case of the product KD of the thickness D of the wave number K and the piezoelectric plate P _R of the acoustic wave is zero V
By employing approximately equal such structures and _{kd = 0,} that the degree of being converted into an electrical signal at the output interdigital transducer an acoustic wave propagating from a non-piezoelectric plate to a two-layer structure L _R is increased In addition, it is possible to eliminate reflection and the like caused by acoustic impedance mismatch at the interface between the piezoelectric plate _PR and the non-piezoelectric plate. By the distance between the electrode fingers as the input interdigital transducer adopts two types of such IDT T _i, exciting the unidirectional acoustic wave to a two-layer structure L _Ti, the elastic wave non It can be propagated through the piezoelectric plate. Excitation of the unidirectional elastic wave not only enables further lower power consumption driving, but also suppresses generation of unnecessary signals. Further, by employing the interdigital electrode R having two kinds of distances between the electrode fingers as the interdigital electrode for output, the unidirectional elastic wave propagated to the non-piezoelectric plate is electrically transmitted from the interdigital electrode R to the non-piezoelectric plate. It can be output as a signal. While the thickness D of each piezoelectric plate is set to be approximately the same as or less than the electrode period length p,
The thickness of the non-piezoelectric plate is set to be approximately the same as or greater than the thickness D of each piezoelectric plate, and the thickness of the non-piezoelectric plate is set to the thickness D of each piezoelectric plate.
By adopting a structure that is approximately 2.5 times or less of
Electrical energy applied from an input interdigital transducer can be increased the degree to be converted into acoustic waves S ₀ mode and first-order or higher-order modes. Further, it is possible to increase the degree of acoustic wave S ₀ mode and first-order or higher-order modes propagating in the non-piezoelectric plate is converted into an electrical signal at the output interdigital transducer. As a non-piezoelectric plate, by the phase velocity of the acoustic wave propagating in a non-piezoelectric plate alone to adopt less material than the phase velocity of the acoustic wave propagating in the piezoelectric plate alone, effectively a two-layer structure L _Ti elastic In addition to exciting a wave and propagating the wave through the non-piezoelectric plate, the elastic wave propagating in the non-piezoelectric plate can be efficiently propagated to the two-layer structure _LR and then output as an electric signal. By adopting piezoelectric ceramics, PVDF or other polymer piezoelectric films as each piezoelectric plate, it is possible to efficiently excite an elastic wave in the two-layer structure part L _Ti and propagate it through the non-piezoelectric plate, and propagate it through the non-piezoelectric plate. After efficiently propagating the elastic wave to the two-layer structure part _LR , it is possible to output it as an electric signal. When a piezoelectric ceramic is used as the piezoelectric plate, a structure is adopted in which the direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction. As the display screen, a substance in which the phase velocity of the elastic wave propagating to the display screen alone is larger than the phase velocity of the elastic wave propagating to the non-piezoelectric plate alone is adopted, so that the two-layer structure part L _{Ti can be used in the} non-piezoelectric plate. the propagated acoustic wave can be propagated efficiently two-layer structure L _R. That is, it is possible to suppress the elastic wave propagated in the non-piezoelectric plate from leaking to the display screen itself. If the tip of the input pen makes contact between the input and output interdigital electrodes on the panel screen with a pressure exceeding a predetermined value, the propagation path of the elastic wave is cut off. The output electric signal disappears or attenuates. Therefore, the contact on the panel screen is sensed in a short response time. At this time, since the elastic wave is a wave that propagates inside the non-piezoelectric plate, the elastic wave does not disappear or attenuate even if it is touched lightly. Therefore, it is possible to eliminate the influence of light hand touching or small amount of foreign matter on the non-piezoelectric plate. In this way, it is possible to realize a touch panel that responds only when touched with a predetermined pen pressure. Further, the coordinates of the contact position are defined by the propagation paths U _Xi and U _{Xi.
If Yi} is made to correspond to two-dimensional coordinates with the X axis and the Y axis, respectively, and the contact position is made to correspond to the intersection of the propagation paths U _Xi and U _Yi , the coordinates of the intersection, that is, the coordinates of the contact position, Prove. In addition, by adopting a structure in which the propagation paths U _Xi are adjacent to each other or partially overlap each other and the propagation paths U _Yi are adjacent to each other or partially overlap each other, the contact position on the panel screen can be more precisely determined. It becomes possible to specify. N for one output IDT
The types of ultrasonic touch panel having a number of input interdigital electrodes, by using the N-number of N of the input connected to the respective interdigital electrodes of the switch C _i or W _i, the contact on the panel screen The position is easily found,
The circuit configuration is simplified. By using the amplifier in a drive circuit, the channel U and _Xi and U _Yi since it is possible to configure the oscillator H _i for a delay element, the circuit structure is simplified, low voltage with low power consumption Can be driven.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of an ultrasonic touch panel according to the present invention.

FIG. 2 is a plan view showing the interdigital transducer T _Xi of FIG. 1;

FIG. 3 is a partial perspective view of the ultrasonic touch panel of FIG. 1;

FIG. 4 is a plan view of the ultrasonic touch panel of FIG. 1;

FIG. 5 is a diagram showing a drive circuit of the ultrasonic touch panel of FIG. 1;

FIG. 6 is a characteristic diagram showing a velocity dispersion curve of an elastic wave propagating through the piezoelectric ceramic plate _PTX alone.

FIG. 7 is a characteristic diagram showing a velocity dispersion curve of an elastic wave propagating through the two-layer structure part L _TXi in FIG. 1;

FIG. 8 shows a piezoelectric ceramic plate P in the two-layer structure part L _TXi of FIG.
FIG. 9 is a characteristic diagram showing a relationship between a K ² value and a KD value calculated from a phase velocity difference under two electrical boundary conditions different in _TX .

FIG. 9 shows a piezoelectric ceramic plate P in the two-layer structure L _TXi of FIG.
FIG. 9 is a characteristic diagram showing a relationship between a K ² value and a KD value calculated from a phase velocity difference under two electrical boundary conditions different in _TX .

FIG. 10 is a characteristic diagram showing a relationship between a K ² value and a KD value calculated from a phase velocity difference under two different electrical boundary conditions of the piezoelectric ceramic plate P _TX in the two-layer structure portion L _TXi of FIG. 1;

11 is a characteristic diagram showing a displacement distribution at a KD value (2.6) near the maximum value of K ² in FIG.

FIG. 12 is a sectional view showing a second embodiment of the ultrasonic touch panel of the present invention.

FIG. 13 is a plan view showing the interdigital transducer I _TXi of FIG. 12;

FIG. 14 is a diagram illustrating a driving circuit of the ultrasonic touch panel in FIG. 12;

FIG. 15 is a sectional view showing a third embodiment of the ultrasonic touch panel of the present invention.

FIG. 16 is a characteristic diagram showing a velocity dispersion curve of an elastic wave propagating through the two-layer structure part L _TXi of FIG. 15;

FIG. 17 is a characteristic diagram showing a relationship between a K ² value and a KD value calculated from a phase velocity difference under two different electrical boundary conditions of the piezoelectric ceramic plate P _TX in the two-layer structure portion L _TXi of FIG.

FIG. 18 is a characteristic diagram showing a relationship between a K ² value and a KD value calculated from a phase velocity difference under two different electrical boundary conditions of the piezoelectric ceramic plate P _TX in the two-layer structure portion L _TXi of FIG.

FIG. 19 is a sectional view showing a fourth embodiment of the ultrasonic touch panel of the present invention.

[Explanation of symbols]

_{DESCRIPTION OF SYMBOLS} 1 Acrylic board 2 Display screen 3 Driving part 4 Frame 5 Voltage rectifier 6 Comparator 7 Information processing part 8 Acrylic board T _Xi , T _Yi , R _X , R _Y interdigital electrodes G _TXi , G _TYi , G _RX , G _RY Ground electrode _{S TX, S TY, S RX} , S RY phase shifter W _Xi, W _Yi switch _{P TX, P TY, P RX} , P RY piezoelectric ceramic plate A _X, A _Y amplifiers L _1, L ₂ coils I _TXi, I _TYi , I _RX , I _RY interdigital transducer C _Xi , C _Yi switch

Claims (13)

[Claims] 1. A non-piezoelectric plate, at least two ultrasonic wave transmitting / receiving means X and Y, and at least one color provided on one or another of the non-piezoelectric plates. An ultrasonic touch panel comprising a display screen and an information processing unit, wherein the information processing unit is connected to each of the ultrasonic transmission / reception means and the display screen, and each of the ultrasonic transmission / reception means comprises N sets. Interdigital electrode I _Ti (i
= 1,2, ..., and the piezoelectric plate P _T with the N), and the piezoelectric plate P _R having the interdigital electrodes I _R, N number of switches C _i (i
= 1,2, ..., become from the N), said interdigital transducer I _Ti is formed on one plate surface of said piezoelectric plate P _T, said interdigital transducer I _R one of the piezoelectric plate P _R is provided on the plate surface, said piezoelectric plate P _T is fixed to the non-piezoelectric plate through said one plate surface or the other plate surface of the piezoelectric plate P _T, said piezoelectric plate P _R is the piezoelectric wherein via the one plate surface or the other plate surface of the plate P _R have been secured to the non-piezoelectric plate, portion P _Ti (i = 1 the piezoelectric plate P _T is corresponding to the interdigital transducer I _Ti , 2, ..., made in N), the non-piezoelectric plate includes a portion corresponding to the portion P _Ti, and a portion corresponding to the piezoelectric plate P _R, the output end of the switch C _i is the interdigital It is connected to the input end of the electrode I _Ti, the interdigital transducer I _Ti corresponds approximately to the interdigital periodicity p of the interdigital transducer I _Ti By inputting an electric signal E _T of the frequency that the portion P
_An elastic wave is excited in a two-layer structure part L _Ti (i = 1, 2,..., N) composed of _Ti and a part corresponding to the part P _Ti of the non-piezoelectric plate. is propagated in non-piezoelectric plate, wherein said acoustic wave excited in the two-layer structure L _Ti in a wave of S ₀ mode and first-order or higher-order mode, the wavelength of the elastic wave the interdigital transducer I _Ti And the phase velocity of the elastic wave is equal to the phase velocity of the elastic wave in the S ₀ mode when the product KD of the wave number K of the elastic wave and the thickness D of the piezoelectric plate _PT is zero. approximately equal to the phase velocity V _{kd = 0,} the interdigital transducer I _R, the a non-piezoelectric the piezoelectric plate is an elastic wave propagating in the plate P _R, corresponding to the piezoelectric plate P _R of the non-piezoelectric plate It is propagated to the two-layer structure L _R comprising a portion substantially corresponding to acoustic wave interdigital periodicity p of the interdigital transducer I _R propagated to the two-layer structure L _R To be converted into an electric signal E _R of the frequency output, the two-layer wavelength of structure the elastic wave propagating in L _R is approximately equal to the interdigital periodicity p of the interdigital transducer I _R, of the elastic wave The phase velocity is determined by the wave number K of the elastic wave and the piezoelectric plate P
Product KD of the thickness D of _R is approximately equal to the phase velocity V _{kd = 0} in the acoustic wave S ₀ mode in the case of zero, the thickness D of the piezoelectric plate is either substantially the same as the respective interdigital periodicity p Or less, and the thickness of the non-piezoelectric plate is approximately equal to or greater than the thickness D of each of the piezoelectric plates, and is approximately 2.5 times or less the thickness D of each of the piezoelectric plates, phase velocity of the elastic wave propagating in a non-piezoelectric plate alone is smaller than the phase velocity of the acoustic wave propagating to the each piezoelectric plate alone, the information processing section sequentially intermittently at a predetermined cycle said switch C _i, The magnitude of the electric signal E _R is detected, and the electric signal E indicates that the pen tip of the input pen contacts the surface of the non-piezoelectric plate having no display screen with a pressure exceeding a predetermined value. determined by the magnitude of _R is attenuated or eliminated, the magnitude of the electrical signal E _R is reduced Ultrasonic touch panel identifies the contact position by identifying the switch C _i which is connected to display information corresponding to the specified the contact position on the display screen when or disappeared. 2. The ultrasonic transmission / reception means X
The propagation path U _Xi (i = 1, 2,..., N) of the elastic wave between the layer structure part L _Ti and the two-layer structure part L _R and the two-layer structure in the ultrasonic wave transmitting / receiving means Y part L channel of the acoustic wave between _Ti and the two-layer structure _{L R U Yi (i = 1,2} , ......,
2. The ultrasonic touch panel according to claim 1, wherein N) are orthogonal to each other. 3. The ultrasonic touch panel according to claim 2, wherein the propagation paths U _Xi are adjacent to each other or partially overlap each other, and the propagation paths U _Yi are adjacent to each other or partially overlap each other. 4. An oscillator H _i (i = 1, 2,..., N) having the propagation paths U _Xi and U _Yi as delay elements, and the switch C in the ultrasonic wave transmitting / receiving means X is provided. input of _i, the are connected via an amplifier a _Y to the output terminal of the interdigital transducer I _R in ultrasonic transmitter unit Y, the input end of the switch C _i in the ultrasonic transmitter means Y , the are connected via an amplifier a _X to the output of the interdigital transducer I _R in ultrasonic transmitter unit X, the signal loop of the oscillator H _i, the said switch in the ultrasonic transmitter means X C _i , the propagation path U _Xi , the amplifier A _X , and the switch C _i in the ultrasonic wave transmitting / receiving means Y, the propagation path U _Yi ,
4. The ultrasonic touch panel according to claim 2, comprising the amplifier _AY . 5. A non-piezoelectric plate, at least two ultrasonic wave transmitting / receiving means X and Y, and at least one type of color provided on one or another of the non-piezoelectric plates. An ultrasonic touch panel comprising a display screen and an information processing unit, wherein the information processing unit is connected to each of the ultrasonic transmission / reception means and the display screen, and each of the ultrasonic transmission / reception means comprises N sets. Interdigital transducer T _i (i
= 1, 2,..., N) and N ground electrodes G _Ti (i =
1, 2, a piezoelectric plate P _T with the N), and the piezoelectric plate P _R having the interdigital electrodes R and the ground electrode G _R, the phase shifter S
And _T, the phase shifter S _R, N sets of switches W _{i (i} = 1,2,
...... made from a N), said interdigital transducer T _i is provided on one plate surface of said piezoelectric plate P _T, the ground electrode G _Ti is provided on the other plate surface of the piezoelectric plate P _T and the interdigital electrode R is formed on one plate surface of said piezoelectric plate P _R, the ground electrode G _R is provided on the other plate surface of the piezoelectric plate P _R, the piezoelectric plate P _T is fixed to the non-piezoelectric plate via the ground electrode G _Ti, said piezoelectric plate P _R is not secured to the non-piezoelectric plate via the ground electrode G _R, the piezoelectric plate P _T is the blind portion P corresponding to Jo electrode T _{i
Ti (i = 1,2, ......,} N) made in said non-piezoelectric plate includes a portion corresponding to the portion P _Ti, and a portion corresponding to the piezoelectric plate P _R, the IDT T _i consists electrode T _i-1 and T _i-2, there are two types of distance between the electrode T _i-1 between the electrode fingers and the electrode T _i-2 of the electrode fingers, said switch and W _i Switch _Wi-1 and Switch _Wi-2
Made, the output end of the switch W _i-1 is connected to the input end of the electrode T _i-1, an output terminal of the switch W _i-2 is connected to the input end of the electrode T _i-2 and, said phase shifter S _T comprises at least one coil L _1, the coil L ₁ is connected to an input terminal of the switch W _i-1 or W _i-2, the interdigital electrode T _i And the ground electrode G _Ti is provided between the electrode T _i-1 and the ground electrode G _Ti and the electrode T _Ti.
The electrical signals E _T1 and E _T2 having a phase difference 2πy between the _i-2 and the ground electrode G _Ti that is input via the phase shifter S _T, and the portion P _Ti, said non-piezoelectric A two-layer structure L comprising a portion of the plate corresponding to the portion P _Ti
An elastic wave is excited to _Ti (i = 1, 2,..., N), and the elastic wave is propagated through the non-piezoelectric plate. The frequency of the electric signals E _T1 and E _T2 is changed to the interdigital electrode T _i. The elastic wave excited in the two-layer structure part L _Ti is a wave of the S ₀ mode and a first-order or higher-order mode, and the wavelength of the elastic wave is The phase velocity of the elastic wave is substantially equal to the electrode period length p of the electrode T _i , and the phase velocity of the elastic wave is the S ₀ mode when the product KD of the wave number K of the elastic wave and the thickness D of the piezoelectric plate _PT is zero. Is approximately equal to the phase velocity V _{kd = 0} of the elastic wave, and the interdigital transducer R comprises electrodes R _-1 and R _-2 , and the electrode finger of the electrode R _{-1 and} the electrode finger of the electrode R _-2 There are two types of distance between the phase shifter S _R comprises at least one coil L _2, the coil L ₂ exits of the electrode R _-1 or R _-2 Is connected to the end, the IDT R and the ground electrode G _R is an acoustic wave which is propagated in said non-piezoelectric plate and the piezoelectric plate P _R,
The non-piezoelectric plate is propagated to a two-layer structure L _R consisting of the portion corresponding to the piezoelectric plate P _R of the electric signal E _R1 having a phase difference 2πy acoustic wave propagating in the two-layer structure L _R and outputs as the E _R2 and the electrode R _-1 and between the electrode R _-2 and said ground electrode G _R from between the ground electrode G _R, the phase shifter S _R is the electrical signal E _R1 and E _R2 is synthesized and output as an electric signal E _R having the same phase, and the frequency of the electric signals E _R1 and E _R2 substantially corresponds to the electrode period length p of the interdigital transducer R. L wavelength of the elastic wave propagating in _R is approximately equal to the interdigital periodicity p of the interdigital transducer I _R, the phase velocity of the elastic wave of the elastic wave wave number K and the piezoelectric plate P
Product KD of the thickness D of _R is approximately equal to the phase velocity V _{kd = 0} in the acoustic wave S ₀ mode in the case of zero, the thickness D of the piezoelectric plate is either substantially the same as the respective interdigital periodicity p Or less, and the thickness of the non-piezoelectric plate is approximately equal to or greater than the thickness D of each of the piezoelectric plates, and is approximately 2.5 times or less the thickness D of each of the piezoelectric plates, phase velocity of the elastic wave propagating in a non-piezoelectric plate alone is smaller than the phase velocity of the acoustic wave propagating to the each piezoelectric plate alone, the information processing section sequentially intermittently at a predetermined cycle said switch W _i, The magnitude of the electric signal E _R is detected, and the electric signal E indicates that the pen tip of the input pen contacts the surface of the non-piezoelectric plate having no display screen with a pressure exceeding a predetermined value. determined by the magnitude of _R is attenuated or eliminated, the magnitude of the electrical signal E _R is reduced Ultrasonic touch panel identifies the contact position by identifying the switch W _i which is connected to display information corresponding to the specified the contact position on the display screen when or disappeared. 6. An electrode finger of said electrode T _i-1 and said electrode T _i-2.
X <1/2 at the shorter distance xp of the distances between the electrode fingers and at the same time, x + y = ± 1/2 at the phase difference 2πy between the electric signals E _T1 and E _T2. Where x <1/2 at a shorter distance xp of the distance between the electrode finger of the electrode R- _{1 and} the electrode finger of the electrode R- ₂ .
At the same time, the phase difference 2 between the electric signals E _R1 and E _R2
6. The ultrasonic touch panel according to claim 5, wherein x + y = ± 1/2 is satisfied in πy. 7. The ultrasonic transmission / reception means X
The propagation path U _Xi (i = 1, 2,..., N) of the elastic wave between the layer structure part L _Ti and the two-layer structure part L _R and the two-layer structure in the ultrasonic wave transmitting / receiving means Y part L channel of the acoustic wave between _Ti and the two-layer structure _{L R U Yi (i = 1,2} , ......,
7. The ultrasonic touch panel according to claim 5, wherein N) is orthogonal to each other. 8. The ultrasonic touch panel according to claim 7, wherein the propagation paths U _Xi are adjacent to each other or partially overlap each other, and the propagation paths U _Yi are adjacent to each other or partially overlap each other. 9. An oscillator H _i (i = 1, 2,..., N) having the propagation paths U _Xi and U _Yi as delay elements, and wherein the phase shift in the ultrasonic wave transmitting / receiving means X is performed. vessel S input of _T, the ultrasonic transmitting and receiving the phase shifter in the decoupling means Y S _R
Of which is connected through an amplifier A _Y to the output terminal, the input of the phase shifter S _T in ultrasonic transmitter unit Y, the said phase shifters S in the ultrasonic transmitter means X _R
Of which is connected through an amplifier A _X to the output end, the signal loop of the oscillator H _i, the said phase shifter S _T in ultrasonic transmitter unit X, the switch W _i, the channel U _Xi, the phase shifter S _R, the amplifier A _X, and wherein the phase shifter S _T in ultrasonic transmitter unit Y, the switch W _i, the channel U _Yi, said phase shifter S _R, the amplifier A _Y The ultrasonic touch panel according to claim 7, comprising: 10. The piezoelectric plate according to claim 1, wherein each of the piezoelectric plates is made of a piezoelectric ceramic, and a direction of a polarization axis of the piezoelectric ceramic is parallel to a thickness direction of the piezoelectric ceramic.
10. The ultrasonic touch panel according to 6, 7, 8 or 9. 11. The method according to claim 1, wherein each of the piezoelectric plates is made of PVDF or another piezoelectric polymer compound.
10. The ultrasonic touch panel according to 7, 8, or 9. 12. The method according to claim 1, wherein said non-piezoelectric plate is made of acrylic or another polymer compound.
The ultrasonic touch panel according to 8, 9, 10 or 11. 13. The phase velocity of an elastic wave propagating on the display screen alone is higher than the phase velocity of an elastic wave propagating on the non-piezoelectric plate alone. ,
The ultrasonic touch panel according to 8, 9, 10, 11 or 12.