JPH11219255A - Ultrasonic wave touch panel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To detect a position where a human finger or an object is brought into contact with the plate surface of a piezoelectric substrate. SOLUTION: When electric signals are inputted to an interdigital electrode 2, elastic waves are excited to the piezoelectric substrate 1 and the elastic waves are respectively converted to electric signals E1a and E1b having frequencies f1a and f1b by means of parts R1a and R1b . Between the interdigital electrodes 2 and 3, ultrasonic wave propagation paths Z1a and Z1b corresponding to the respective parts R1a and R1b are formed. The electric signals E1a corresponding to the ultrasonic wave propagation path Z.. are outputted from the interdigital electrode 3 when the piezoelectric substrate 1 is brought into contact and the ultrasonic wave propagation path Z1b , is interrupted and the electric signals E1b , are outputted when the ultrasonic wave propagation path Z1b is interrupted. In such a manner, from the frequency of the output electric signals, a position brought into contact is discriminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ultrasonic touch panel for detecting a position at which a finger or an object comes into contact with a plate surface of a piezoelectric substrate provided with input and output IDTs.

2. Description of the Related Art A conventional touch panel based on an ultrasonic method utilizes the fact that a surface acoustic wave is excited on a non-piezoelectric plate and the surface acoustic wave is attenuated by contact with the non-piezoelectric plate. 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 transducers are methods in which a piezoelectric thin film such as ZnO is deposited on a substrate and surface acoustic waves are excited by interdigital electrodes.
It is limited to the F and VHF bands and has problems in workability and mass productivity. As described above, the conventional ultrasonic touch panel has problems in response time, sensitivity, durability, machining accuracy, workability, mass productivity, ease of use, and the like, and the frequency range of use is also limited. Further, in the conventional touch panel, a signal processing method has to be complicated.

The conventional ultrasonic touch panel has problems not only in sensitivity, machining accuracy, workability, mass productivity, power consumption, etc. but also in signal processing method and circuit configuration. Was. An object of the present invention is to provide an ultrasonic wave having excellent workability, durability and mass productivity, low power consumption driving, short response time, simple signal processing method, small circuit scale, and excellent usability. It is to provide a touch panel.

An ultrasonic touch panel according to claim 1, wherein a piezoelectric substrate, two ultrasonic transmitting / receiving means provided on one plate surface of said piezoelectric substrate, and said two ultrasonic waves. An ultrasonic touch panel comprising an information processing unit connected to a transmitting / receiving unit, wherein each of the ultrasonic transmitting / receiving units includes at least one set of input IDTs and an output IDT corresponding to the input IDTs. , And the intersecting region of the electrode fingers of the output IDT consists of one group R _i (i = 1) or N groups R _i (i = 1, 2,...). , N) and the two groups R _i
And sandwiched R _{(i + 1) (N-1)} pieces of partial Q _i {i =
1,2, ......, (N-1 ) consists}, each group R _i comprises two portions R _ia and R _ib, from a portion sandwiched by R _{i m} to, the portion R _ia and R The direction of each electrode finger of the _ib is parallel to the direction of the electrode finger of the input IDT, and the electrode period length of each of the portions R _ia and R _ib is equal to the electrode period length P of the input IDT,
It said portion electrode fingers of the R _im has an inclination of angle α with respect to the electrode fingers of said input interdigital transducer, periodicity P _RN electrode fingers in a direction perpendicular to the electrode fingers of the part R _im is the equal to the product of the interdigital periodicity P and cos [alpha], the electrode crossing width of the portion R _im is the overlap length L _RP in the direction of the electrode fingers of the part R _im,
There are two types of crossing width L _RN in the direction parallel to the electrode fingers of the input IDT, and the crossing width L _RP is equal to the product of the crossing width L _RN and secα and the electrode period equal to the product of half the cosecα length P, the electrode fingers of the part Q _i has a slope of angle ± beta to the electrode fingers of said input interdigital transducer, perpendicular to the electrode fingers of the part Q _i the periodicity P _QN of the electrode fingers in the direction equal to the product of the electrode periodicity P and cos .beta, the portion in the electrode crossing width of Q _i, the portion Q _i overlap length L in the direction of the electrode fingers and _QP, there are two types of cross width L _QN in the direction parallel to the electrode fingers of said input interdigital transducer, the overlap length L _QP is equal to the product of the overlap length L _QN and Secbeta, said portion The sum of the electrode cross width of each of R _ia and R _ib , the cross width L _RN, and the cross width L _QN is the electrode of the input IDT. The input IDT is substantially equal to the crossing width L, and the input IDT electrode receives an electric signal to excite ultrasonic waves to the piezoelectric substrate, and
_ia and R _{ib convert the} ultrasonic waves into electrical signals E _ia and E _ib
(I = 1, 2,..., N), the amplitude of the electric signal generated by combining the electric signals E _ia and E _ib is zero, and the input and output IDTs are , In the piezoelectric substrate, the portions R _ia and R
_ib corresponding to the ultrasonic wave propagation paths Z _ia and Z _ib (i
= 1, 2,..., N), and positions F _ia and F _ib (i = 1, 2,..., N) on the piezoelectric substrate correspond to the ultrasonic propagation paths Z _ia and Z _ib , respectively. The output interdigital transducer is configured such that the electric signal E _ib or the electric signal E _{ib is} output only when a finger or an object comes into contact with the position F _ia or F _ib and the ultrasonic wave propagation path Z _ia or Z _ib is interrupted. E _ia , and the information processing section outputs one of the positions F _ia F
_Xa is in contact with the position F _Xa and the position F _Xb
Electrical signals E _Xb corresponding to senses by being output from the interdigital electrode and the output or the position F _Xb
Is contacted with an electric signal E corresponding to the position F _Xa.
Xa is sensed by being output from the output IDT. 3. The ultrasonic touch panel according to claim 2, wherein the intersection width L _QP is equal to the electrode cycle length P in the group Ri.
Is equal to the product of the value obtained by dividing by twice the number N and cosecβ.
The ultrasonic touch panel according to claim 3, wherein a piezoelectric substrate,
An ultrasonic touch panel including two ultrasonic wave transmitting / receiving units provided on one plate surface of the piezoelectric substrate and an information processing unit connected to the two ultrasonic wave transmitting / receiving units. The wave means comprises at least one set of input interdigital transducers and an output interdigital transducer corresponding to the input interdigital transducer, and the intersecting regions of the input interdigital transducers have N portions A. _i (i = 1, 2,..., N)
And the two parts A _i and A _{(i + 1)} (N−
1) number of partial _{B i {i = 1,2, ......} , (N-1)} consists, intersections of the electrode fingers of the output interdigital transducer, (N + 1) pieces of partial C _i {i = 1,2, ..., (N
+1)} and N portions D _i (i = 1, 2,..., N) sandwiched between the two portions C _i and C _{(i + 1)} ,
Said portion A direction of the electrode fingers of _i is parallel to the direction of the electrode fingers of the portions C _i, the electrode fingers of the portion B _i has an inclination of angle -β with respect to the electrode fingers of the portions A _i, the period length P _BN electrode fingers in a direction perpendicular to the electrode fingers of the portions B _i, the portion a _i
And equal to the product of the interdigital periodicity P and cosβ of C _i, the portion in the electrode crossing width B _i, the overlap length L _BP in the direction of the electrode fingers of the portion B _i, the electrode of the portion A _i There are two types of cross width L _BN in the direction parallel to the finger, the overlap length L _BP is equal to the product of the overlap length L _BN and Secbeta, the electrode fingers of the part D _i is the portion C _i Has an angle α with respect to the electrode finger,
Periodicity P _DN of the electrode fingers in a direction perpendicular to the electrode fingers of the part D _i is equal to the product of the electrode periodicity P and cos [alpha],
The electrode crossing width of the portion D _i is the overlap length L _DP in the direction of the electrode fingers of the part D _i, are two types of cross width L _DN in the direction parallel to the electrode fingers of the portion C _i Yes, the intersection width L _DP
Is equal to the product of the intersection width L _DN and secα,
The sum of the electrode finger intersection width and the intersection width L _BN of the portion A _i is equal to the product of half of the electrode cycle length P and cosec α, and the intersection width of the electrode finger of the portion C _i and the intersection width L _BN Almost equal to the sum of _DN, the input IDT is
When an electric signal is input, an ultrasonic wave is excited on the piezoelectric substrate, and the output IDT converts the ultrasonic wave into N.
The electric signals E _ia (i = 1, 2,..., N) and N electric signals E _ib (i = 1, 2,..., N) are converted into the electric signals E _ia and E _ib. Are zero, and the input and output IDTs are connected to the N ultrasonic wave propagation paths Z _ia (i = 1, 2,..., N) and N ultrasonic wave propagation paths Z _ib (i = 1, 2,..., N), and the ultrasonic wave propagation path Z _ia is provided between the portions A _i and C _i. The propagation path Z _ib is between the portions A _i and C _{(i + 1)} , and positions F _ia and F _ib (i = 1, 2,... _{) On} the piezoelectric substrate.
.., N) respectively correspond to the ultrasonic wave propagation paths Z _ia and Z _ib , and the output interdigital transducer is connected to the position F _ia or F _ib when a finger or an object comes into contact with the ultrasonic wave propagation paths Z _ia and Z _ib.
Only when _ia or Z _ib is interrupted, the electric signal E
_ib or _Eia , and the information processing section outputs the position F
that it has contact with one F _Xa of _ia, or electrical signal E _Xb corresponding to the position F _Xb forming the position F _Xa paired senses by being output from the interdigital electrode said output, or The contact with the position F _Xb is sensed by outputting an electric signal _Exa corresponding to the position F _Xa from the output IDT. In the ultrasonic touch panel according to the fourth aspect, the intersection width L _BP is equal to a product of a value obtained by dividing the electrode cycle length P by twice the number N of the portions A _i and cosec β. The ultrasonic touch panel according to claim 5, wherein the information processing unit includes an amplifier and a signal processor, and an output end of the output IDT is connected to an input end of the input IDT via the amplifier. Connected to the input of the signal processor, the electrical signals E _ia and E _ib have frequencies f _ia and f _ib , respectively, and the signal processor indicates the contacted position F _Xa to the electrical signal _{EX b} identifying by either identifying or the position F _Xb in contact for detecting the frequency f _Xa of the electric signal E _Xa by detecting the frequency f _Xb. 7. The ultrasonic touch panel according to claim 6, wherein each of the ultrasonic wave transmitting and receiving means includes two reference interdigital transducers, one of the reference interdigital transducers being used for input and the other being used for output. The directions of the electrode fingers of the two reference IDTs are parallel to each other;
The information processing unit includes an amplifier, a phase comparator, and a signal processor, and an output end of the other reference IDT is connected to the one reference IDT and the input IDT via the amplifier. Connected to the input terminal of each of the phased electrodes and to the input terminal of the phase comparator,
The output end of the output IDT is connected to the input end of the signal processor via the phase comparator, and the one reference IDT is connected to the piezoelectric substrate by receiving an electric signal. Exciting the ultrasonic wave, the other reference IDT converts the ultrasonic wave into an electric signal having a phase θ _base and outputs the electric signal, and outputs the electric signals E _ia and E
_ib have phases θ _ia and θ _ib , respectively, the phase comparator detects a difference between the phase θ _base and the phase θ _ia or θ _ib, and the signal processor processes the position F _Xa
Is determined based on the difference between the phase θ _base and the phase θ _Xb of the electric signal _EXb , or the contacted position F _Xb is determined by the difference between the phase θ _base and the phase θ _Xa of the electric signal _EXa. Specify based on. 8. The ultrasonic touch panel according to claim 7, wherein the electrode cycle length P is larger than the thickness d of the piezoelectric substrate, and the input interdigital transducer is provided with the electrode cycle length P. 9.
, An elastic wave having a wavelength substantially equal to the electrode period length P is excited in the piezoelectric substrate. 9. The ultrasonic touch panel according to claim 8, wherein the electrode cycle length P has a value equal to or less than one third of the thickness d of the piezoelectric substrate, and the input IDT has an electrode cycle length P When an electric signal having a frequency substantially corresponding to the input is input, a surface acoustic wave having a wavelength substantially equal to the electrode period length P is excited near the surface of the one plate surface of the piezoelectric substrate. The ultrasonic touch panel according to claim 9, wherein the piezoelectric substrate is made of piezoelectric ceramic,
The direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction of the piezoelectric ceramic. The ultrasonic touch panel according to claim 10, wherein the ultrasonic wave propagation paths Z _ia and Z _ib in one of the ultrasonic wave transmitting and receiving means and the ultrasonic wave propagation paths Z _ia and Z _ia in the other ultrasonic wave transmitting and receiving means. Z
_ib are orthogonal to each other.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An ultrasonic touch panel according to the present invention is connected to a piezoelectric substrate, two ultrasonic wave transmitting / receiving means provided on one plate surface of the piezoelectric substrate, and two ultrasonic wave transmitting / receiving means. It consists of an information processing unit. Each ultrasonic wave transmitting / receiving means comprises at least one set of input IDTs and output IDTs corresponding to the input IDTs. In the first structure of the ultrasonic touch panel of the present invention, the input IDT has a regular structure. The intersecting region of the electrode fingers of the output IDT consists of only one group R _i (i = 1) or N groups R _i (i = 1, 2,...).
, N) and (N-1) parts Q _i ii = 1, 2,..., (N− ₎ sandwiched between two groups R _i and R _{(i + 1)}
1) Consists of｝. Each group R _i comprises two parts R _ia and R _ib and a part R _im sandwiched between them. Part R
The direction of the electrode fingers of _ia and R _ib is parallel to the direction of the electrode fingers of the input IDT, and the electrode cycle length of the portions R _ia and R _{ib is} the electrode _pitch P of the input IDT.
Is equal to Partial electrode fingers of the R _im has an inclination of angle α with respect to the electrode fingers of the input IDT, the moiety R periodicity P _RN electrode fingers in a direction perpendicular to the electrode fingers of the _im, the electrode periodicity P And co
Equal to the product of sα. The electrode cross width of the portion R _im, and overlap length L _RP in the direction of the electrode finger portions R _im, there are two types of cross width L _RN in the direction parallel to the electrode fingers of the input IDT , The intersection width L _RP is equal to the product of the intersection width L _RN and secα, and equal to the product of half the electrode period length P and cosec α. Partial electrode fingers of Q _i has a slope of angle ± beta to the electrode fingers of the input IDT, the period length P _QN of the electrode fingers in a direction perpendicular to the electrode fingers of the part Q _i, interdigital periodicity P and cos
Equal to the product of β. The electrode cross width portion Q _i, part Q _i
And overlap length L _QP in the direction of the electrode fingers, there are two types of cross width L _QN in the direction parallel to the electrode fingers of the input interdigital transducer, overlap length L _QP is the overlap length L _QN and secβ Equal to the product of
Furthermore, the intersection width L _QP can take a value equal to a product of a value (P / 2N) obtained by dividing the electrode period length P by twice the number N of the groups R _i and cosec β. Parts R _ia and R
_ib , electrode cross width, cross width L _RN , cross width L _QN
Is substantially equal to the electrode intersection width L of the input IDT. In the first structure of the ultrasonic touch panel of the present invention,
By inputting an electric signal to the input IDT, ultrasonic waves can be excited on the piezoelectric substrate. This ultrasonic wave is transmitted by the parts R _ia and R _ib to the electric signals E _ia and E
_ib (i = 1, 2,..., N). At this time, the amplitude of the electric signal generated by combining the electric signals E _ia and E _ib becomes zero. This is the intersection width L _RP
Is equal to the product of the intersection width L _RN and secα and equal to the product of half the electrode period length P and cosecα. The input and output IDTs form ultrasonic propagation paths Z _ia and Z _ib (i = 1, 2,..., N) corresponding to the portions R _ia and R _{ib on} the piezoelectric substrate. In other words, between the input and output IDTs,
So that the ultrasonic wave propagation path of twice the number N of groups R _i (2N pieces) are present. If the position F on the piezoelectric substrate
_ia or _{F ib (i = 1,2, ......} , N) when a person finger or object contacting, ultrasonic propagation path Z _ia or Z _ib corresponding to the position F _ia or F _ib is cut off, this time ,
An electrical signal E _ib or E _ia is output from the output IDT. The information processing unit may be that in contact with one F _Xa of the position F _ia, the electric signal E _Xb corresponding to the position F _Xb and forming a position F _Xa paired output from the output interdigital transducer Is sensed by The information processing unit in the same manner are sensed by that in contact with the position F _Xb, the electric signal E _Xa corresponding to the position F _Xa is output from the output interdigital transducer. In this manner, the ultrasonic touch panel of the present invention can output the electric signal E _ib or E _ia corresponding to the position F _ia or F _ib of the contacted piezoelectric substrate, respectively. Second ultrasonic touch panel of the present invention
In the above structure, the intersecting regions of the electrode fingers of the input IDT are divided into N parts A _i (i = 1, 2,..., N) and two parts A _i and A _{(i + 1)} . (N−1) parts B _i {i = 1, 2,..., (N−1)} sandwiched therebetween, and the intersection area of the electrode fingers of the output IDT is (N + 1) The part C _i {i = 1, 2,..., (N + 1)} and the N parts D _i (i = ₂₎ sandwiched between the two parts C _i and C _{(i + 1)}
1, 2,..., N). The direction of the electrode finger of the part A _i is parallel to the direction of the electrode finger of the part C _i . The electrode finger portion B _i has an inclination of angle -β with respect to the electrode finger portions A _i, the period length of the electrode fingers in a direction perpendicular to the electrode fingers of the portions B _i P
_BN is equal to the product of the electrode period length P of the parts A _i and C _i and cos β. The electrode cross width of the portion B _i, there are two types of the cross width L _BP in the direction of the electrode finger portion B _i, the overlap length L _BN in the direction parallel to the electrode fingers of the portions A _i. The intersection width L _BP is equal to the product of the intersection width L _BN and secβ. Further, the intersection width L
_BP is a value obtained by dividing twice the number N of the electrode periodicity P part A _i (P / 2N), it is possible to take a value equal to the product of the Cosecbeta. Part D _i electrode fingers has an inclination of angle α with respect to the electrode finger portions C _i, periodicity P _DN of the electrode fingers in a direction perpendicular to the electrode fingers of the part D _i is the electrode periodicity P and cosα Equal to the product of The electrode cross width of the portion D _i, there are two types of the cross width L _DP in the direction of the electrode finger portions D _i, the overlap length L _DN in the direction parallel to the electrode fingers of the portion C _i. The intersection width L _DP is
It is equal to the product of the intersection width L _DN and secα and equal to the product of half of the electrode period length P and cosec α. Partial sum of A _i intersection width and overlap length L _BN of the electrode fingers is approximately equal to the sum of the cross width of the electrode finger portions C _i and overlap length L _DN. In the second structure of the ultrasonic touch panel according to the present invention, ultrasonic waves can be excited on the piezoelectric substrate by inputting an electric signal to the input IDT. The ultrasonic waves are output by the output IDT electrodes into N electrical signals E _ia (i = 1, 2,...).
.., N) and N electric signals E _ib (i = 1, 2,...)
.., N). The amplitude of the electric signal generated by combining the electric signals E _ia and E _ib becomes zero. This is because the intersection width L _DP is equal to the product of the intersection width L _DN and secα and equal to the product of half the electrode period length P and cosec α. The input and output IDTs are connected to N ultrasonic wave propagation paths Z _ia (i =
1, 2,..., N) and N ultrasonic propagation paths Z _ib (i
= 1, 2,..., N). That is, there are twice as many (2N) ultrasonic propagation paths as the number N of the parts A _i between the input and output IDTs, and the ultrasonic propagation paths Z _ia are _equal to the parts A _i . During C _i, the ultrasonic wave propagation path Z _ib
Lies between the parts A _i and C _{(i + 1)} . If a finger or an object touches the position F _ia or F _ib (i = 1, 2,..., N) on the piezoelectric substrate, the ultrasonic wave propagation path Z _ia or Z corresponding to the position F _ia or F _ib respectively. _ib is shut off,
At this time, the electric signal E _ib or E _ia is output from the output IDT. The information processing section determines one of the positions F _ia
One F _Xa that contacts the is sensed by an electrical signal E _Xb corresponding to the position F _Xb and forming a position F _Xa and pair is outputted from the output interdigital transducer. The information processing unit in the same manner are sensed by that in contact with the position F _Xb, the electric signal E _Xa corresponding to the position F _Xa is output from the output interdigital transducer. In this manner, the ultrasonic touch panel of the present invention can output the electric signal E _ib or E _ia corresponding to the position F _ia or F _ib of the contacted piezoelectric substrate, respectively. In the ultrasonic touch panel of the present invention, the touched position F _ia or F _ib can be specified by the frequency f _ib or f _ia of the output electric signal E _ib or E _ia, respectively. In this case, the information processing unit includes an amplifier and a signal processor. The output end of the output IDT is connected via an amplifier to the input end of the input IDT and the input end of the signal processor. The signal processor determines the touched position F _Xa as the frequency f of the electric signal E _Xb .
Specified by detecting _Xb . Similarly, the touched position F _Xb is specified by detecting the frequency f _Xa of the electric signal E _Xa . In the ultrasonic touch panel of the present invention,
The touched position F _ia or F _ib can be specified from the difference between the phase θ _ib or θ _ia of the output electric signal E _ib or E _ia, respectively, and the reference phase θ _base . In this case, the information processing unit includes an amplifier, a phase comparator, and a signal processor, and each ultrasonic transmitting / receiving means includes two reference IDTs, one of which is used for input and the other is used for output. Can be The directions of the electrode fingers of the two reference IDTs are parallel to each other. The output terminal of the reference IDT for output is connected to the input terminal of the IDT for reference and the input terminal of the IDT for input via an amplifier, and the input terminal of the phase comparator. Connected to. The output terminal of the output IDT is connected to the input terminal of the signal processor via a phase comparator. When an electric signal is input to the reference interdigital transducer for input, an ultrasonic wave is excited on the piezoelectric substrate, and the ultrasonic wave is converted into an electric signal having a phase θ _base by the reference interdigital transducer for output and output. Is done. If the position F _Xb is touched, the difference between the phases θ _base and θ _Xa (θ _base
−θ _Xa ) is detected, and when it comes into contact with the position F _Xa , the difference (θ _base −θ _ib ) between the phases θ _base and θ _ib is detected by the phase comparator. The signal processor specifies the touched position F _{Xa based} on the phase difference (θ _base −θ _Xb ). Similarly, the touched position F _Xb is specified based on the phase difference (θ _base −θ _Xa ). In the ultrasonic touch panel of the present invention, a structure in which the electrode cycle length P is larger than the thickness d of the piezoelectric substrate is possible. In this case, the input IDT is capable of exciting an elastic wave having a wavelength substantially equal to the electrode period length P to the piezoelectric substrate by receiving an electric signal having a frequency substantially corresponding to the electrode period length P. Becomes In a device using such an elastic wave, when a position F _ia or F _ib on one of the plate surfaces of the piezoelectric substrate is brought into contact, an electric signal E _ib or E _ia is generated. In the ultrasonic touch panel of the present invention, a structure in which the electrode cycle length P has a value equal to or less than one third of the thickness d of the piezoelectric substrate is possible. In this case, the input interdigital transducer receives an electric signal having a frequency substantially corresponding to the electrode periodic length P, so that the electrode periodic length P is located near the surface of the plate surface of the piezoelectric substrate having the interdigital transducer. It is possible to excite surface acoustic waves having substantially the same wavelength. In a device using such a surface acoustic wave, when a position F _ia or F _ib on the surface of the piezoelectric substrate having the interdigital electrodes is brought into contact, an electric signal E is generated.
_{Either ib} or _Eia occurs. The ultrasonic touch panel of the present invention employs a piezoelectric ceramic as the piezoelectric substrate and adopts a structure in which the direction of the polarization axis of the piezoelectric ceramic is parallel to the direction of the thickness d. Device can be provided. In the ultrasonic touch panel of the present invention, the ultrasonic propagation path Z _ia and Z _ib in one ultrasonic transmitter means and an ultrasonic propagation path Z _ia and Z _ib at the other ultrasonic transmitter means perpendicular to each other By adopting the structure, it is possible to represent the contact position by two-dimensional coordinates with their propagation paths orthogonal to each other as the X axis and the Y axis, respectively.

FIG. 1 is a plan view showing a first embodiment of an ultrasonic touch panel according to the present invention. In this embodiment, the piezoelectric substrate 1, X
It comprises ultrasonic wave transmitting / receiving means X in the axial direction, ultrasonic wave transmitting / receiving means Y in the Y-axis direction, and information processing section Z. However, only the piezoelectric substrate 1 and the ultrasonic wave transmitting / receiving means X and Y are illustrated in FIG. Each ultrasonic wave transmitting / receiving means comprises an input IDT 2 and an output IDT 3. The interdigital electrodes 2 and 3 are made of an aluminum thin film and have ten pairs of electrode fingers, and are provided on the upper end surface of the piezoelectric substrate 1. Piezoelectric substrate 1
Is made of a piezoelectric ceramic having a thickness d of 1.5 mm, and the direction of the polarization axis is parallel to the direction of the thickness d. FIG. 2 is a diagram showing the relative structure between the interdigital electrodes 2 and 3. The IDT 2 has a regular structure, and its electrode period length P
Is 1.7 mm, and the electrode intersection width L is 15 mm. The intersection area of the electrode fingers of the interdigital electrode 3 is one group R ₁
The group R ₁ is composed of two parts R _1a and R _1b and a part R _1m sandwiched between them. Parts R _1a and R
_1b direction of each of the electrode fingers is parallel to the direction of the electrode fingers of the interdigital electrodes 2, portions R _1a and R _1b each electrode period length is equal to the electrode periodicity P interdigital electrodes 2. FIG. 3 is an enlarged plan view of the portion R _1m . Partial electrode fingers of the R _{1 m} has an inclination of angle α with respect to the electrode fingers of the interdigital electrodes 2, periodicity P _RN electrode fingers in a direction perpendicular to the electrode fingers of the portion R _{1 m} is the electrode periodicity P Equivalent to the product of _cos α. Portion to the electrode cross width of R _{1 m,} there are two types of the cross width L _RP in the direction of the electrode finger portions R _{1 m,} the cross width L _RN in the direction parallel to the electrode fingers of the interdigital electrodes 2. The intersection width L _RP is equal to the product of the intersection width L _RN and secα and equal to the product of half of the electrode period length P and cosecα. The portion R _1a and R _1b each electrode intersection width (7 mm), portion R _{1 m} overlap length L _RN (1 m of
m) is equal to the electrode cross width L (15 m
m). FIG. 4 is a circuit configuration diagram of the ultrasonic touch panel of FIG. 4 includes an information processing unit Z,
The information processing section Z includes an amplifier 4 and a signal processor 5.
The output terminal of the IDT 3 is connected to the input terminal of the IDT 2 and the input terminal of the signal processor 5 via an amplifier 4. When an electric signal having a frequency substantially corresponding to the electrode period length P is input to the interdigital transducer 2, an elastic wave having a wavelength substantially equal to the electrode period length P is excited in the piezoelectric substrate 1. The acoustic wave is respectively converted into electric signals E _1a and E _1b having a frequency f _1a and f _1b by the portion R _1a and R _1b. At this time, the amplitude of the electric signal generated by combining the electric signals E _1a and E _1b becomes zero. The IDTs 2 and 3 are formed on the piezoelectric substrate 1 by ultrasonic propagation paths Z _1a and Z _1b corresponding to the portions R _1a and R _1b, respectively.
To form If, at the upper surface or lower surface of the piezoelectric substrate 1, the contact position F _1b is a human finger or an object is an ultrasonic propagation path Z _1b is cut off, the electric signal E _1a corresponding to the ultrasonic propagation path Z _1a Is output from the interdigital electrode 3. Similarly, when the ultrasonic wave propagation path _Z1a is cut off by touching the position _F1a , an electric signal _E1b is output. That is, when the upper end surface or the lower end surface of the piezoelectric substrate 1 is not touched, no electric signal is output from the interdigital electrode 3, but when the position F _1b is touched, an electric signal E _1a having a frequency f _1a is generated. ,
Electrical signals E _1b having position F _1a frequency f _1b in contact with
Is detected by the signal processor 5. Thus, from the frequency of the electric signal detected by the signal processor 5, it can be determined which of the positions _F1a and _F1b has been touched. In addition, the contact position with respect to the ultrasonic wave transmitting / receiving means X and the contact position with respect to the ultrasonic wave transmitting / receiving means Y are simultaneously detected. In this embodiment, two ultrasonic wave transmitting / receiving means X and Y are used, and the ultrasonic wave propagation paths Z _1a and Z _{1b in the} ultrasonic wave transmitting / receiving means X are used.
And the ultrasonic wave propagation paths Z _1a and Z _1b in the ultrasonic wave transmitting / receiving means Y are orthogonal to each other. The position can be represented.
The electric signal E _1a or E _1b output from the IDT 3
Is amplified by the amplifier 4, and a part of the amplified electric signal is input to the interdigital electrode 2 again. In this manner, since the oscillator using the ultrasonic wave propagation path _Z1a or _Z1b as a delay element only at the time of contact is configured, not only low power consumption driving is possible but also the circuit configuration is simplified. Figure 5 is the product of the electromechanical coupling coefficient k ² calculated from the phase velocity difference between the two electrical boundary conditions of different piezoelectric substrate 1, the thickness d of the frequency f and the piezoelectric substrate 1 of the acoustic wave (fd) FIG. 4 is a characteristic diagram showing a relationship between However, the transverse wave velocity of the elastic wave propagating through the piezoelectric substrate 1 is 2450 m / s, and the longitudinal wave velocity is 439
0 m / s. For example, the fd value when the electric energy applied to the interdigital electrode 2 is converted into an elastic wave of S ₀ mode is about 1.3 MHz · mm, and k ² represents about 12.4% of the maximum value. 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 surface acoustic waves. FIG. 6 is a characteristic diagram illustrating a velocity dispersion curve of an elastic wave propagating through the piezoelectric substrate 1, and is a diagram illustrating a phase velocity of each mode with respect to the fd value. ● mark indicates fd value electric energy applied to interdigital transducer 2 is most efficiently converted into acoustic waves of each mode (with the value calculated from FIG. 5, fd value k ² is the maximum value) . It can be seen that all the phase velocities indicated by ● show values near 3500 m / s. FIG. 7 is a plan view showing a second embodiment of the ultrasonic touch panel of the present invention. In this embodiment, the piezoelectric substrate 1, X
It comprises ultrasonic wave transmitting / receiving means X in the axial direction, ultrasonic wave transmitting / receiving means Y in the Y-axis direction, and information processing section Z. However, only the piezoelectric substrate 1 and the ultrasonic wave transmitting / receiving means X and Y are illustrated in FIG. Each ultrasonic wave transmitting / receiving means comprises four interdigital electrodes 2 and four corresponding interdigital electrodes 3.
FIG. 8 is a circuit configuration diagram of the ultrasonic touch panel of FIG.
The circuit of FIG. 8 includes a switch 6 and an information processing unit Z, and the information processing unit Z includes an amplifier 4 and a signal processor 5. The output terminals of the interdigital transducer 3 are connected to each other at one connection point, and the connection point is connected to the input terminal of the switch 6 and the input terminal of the signal processor 5 via the amplifier 4. The switch 6 has a function of sequentially inputting an electric signal to the four interdigital electrodes 2. When an electric signal is input from the interdigital transducer 2 through the switch 6, an elastic wave is excited in the piezoelectric substrate 1. This elastic wave is generated by the portions R _1a and R _1b
Electrical signals E _1a and E _1b having a frequency f _1a and f _1b
Respectively. If a position F _1b between one of the interdigital transducers 2 in the ultrasonic wave transmitting / receiving means X and the corresponding interdigital transducer 3 on the upper end face or the lower end face of the piezoelectric substrate 1 is brought into contact, an electric signal E is generated. _1a is the position F _1a
, The electric signal E _1b is detected by the signal processor 5. In this manner, the contact position is clarified by discriminating the frequency of the electric signal detected by the signal processor 5 and the only interdigital transducer 2 connected when the electric signal was detected. The same applies to the ultrasonic wave transmitting / receiving means Y. The contact position with respect to the ultrasonic wave transmitting / receiving means X and the contact position with respect to the ultrasonic wave transmitting / receiving means Y are simultaneously detected.
The electric signal E _1a or E _1b output from the IDT 3
Is amplified by the amplifier 4, and a part of the amplified electric signal is input again to the IDT 2 via the switch 6. In this manner, since the oscillator using the ultrasonic wave propagation path _Z1a or _Z1b as a delay element only at the time of contact is configured, not only low power consumption driving is possible but also the circuit configuration is simplified. FIG. 9 is a plan view showing a third embodiment of the ultrasonic touch panel of the present invention. This embodiment comprises a piezoelectric substrate 1, X-axis direction ultrasonic wave transmitting / receiving means X, Y-axis direction ultrasonic wave transmitting / receiving means Y, and information processing section Z. However, FIG.
1, only the piezoelectric substrate 1 and the ultrasonic wave transmitting / receiving means X and Y are illustrated. Each ultrasonic wave transmitting / receiving means comprises reference interdigital electrodes 7 and 8, four interdigital electrodes 2 and four corresponding interdigital electrodes 3. The interdigital electrodes 7 and 8 have a regular structure, and the electrode period length P is 1.7 mm. FIG. 10 is a circuit configuration diagram of the ultrasonic touch panel of FIG. The circuit in FIG. 10 includes an amplifier 4, a switch 6, and an information processing unit Z. The information processing unit Z includes an amplifier 9, a phase comparator 10, and a signal processor 5.
The output terminals of the interdigital transducer 3 are connected to each other at one connection point, and the connection point is connected to the input terminal of the phase comparator 10 via the amplifier 4. The output end of the IDT 8
The amplifier 9 is connected to the input terminal of the interdigital transducer 7 and the input terminal of the switch 6 and to the input terminal of the phase comparator 10. The switch 6 has a function of sequentially inputting an electric signal to the four interdigital electrodes 2. When an electric signal is input from the interdigital electrode 7, an elastic wave is excited in the piezoelectric substrate 1. This elastic wave is converted into an electric signal having a phase θ _base by the interdigital electrode 8 and output.
It is amplified by the amplifier 9. A part of the amplified electric signal is input to the interdigital electrode 7 and the switch 6.
In this way, it is possible to configure an oscillator using the ultrasonic wave propagation path between the interdigital transducers 7 and 8 as a delay element.
The remainder of the amplified electric signal is input to the phase comparator 10. When an electric signal is input from the interdigital transducer 2 through the switch 6, an elastic wave is excited in the piezoelectric substrate 1. The acoustic wave by partial R _1a and R _1b, are respectively converted into electric signals E _1a and E _1b having a phase theta _1a and theta _1b. If a position F _1b between one of the interdigital transducers 2 in the ultrasonic wave transmitting / receiving means X and the corresponding interdigital transducer 3 on the upper end face or the lower end face of the piezoelectric substrate 1 is brought into contact, an electric signal E is generated. _{When 1a} contacts position _F1a , an electrical signal _E1b is output from its interdigital electrode 3. At this time, the phase comparator 10 detects a difference between the phase θ _base and the phase θ _1a or θ _1b . The signal processor 5 identifies the contact position by discriminating the phase difference and the only interdigital transducer 2 connected when the phase difference is detected. The same applies to the ultrasonic wave transmitting / receiving means Y.
The contact position with respect to the ultrasonic wave transmitting / receiving means X and the contact position with respect to the ultrasonic wave transmitting / receiving means Y are simultaneously detected. FIG. 11 is a plan view showing a fourth embodiment of the ultrasonic touch panel of the present invention. This embodiment has a structure in which the output IDT 3 of FIG. 1 is replaced by the output IDT 11. FIG. 12 is a diagram showing the relative structure between the IDTs 2 and 11. The interdigital transducer 11 has ten pairs of electrode fingers, and the intersection area of the electrode fingers is composed of two groups R ₁ and R ₂ and one part Q ₁ , and the part Q ₁ is composed of groups R ₁
And R ₂ . The group R ₁ includes two portions R _1a and R _1b and a portion R _1m sandwiched therebetween, and the group R ₂ includes two portions R _2a and R _2b and a portion R _2m sandwiched therebetween. Moiety R _1a, R _1b, R _2a and R _2b direction of each of the electrode fingers is parallel to the direction of the electrode fingers of the interdigital electrodes 2, part R _1a, R _1b, interdigital periodicity of each R _2a and R _2b It is equal to the electrode period length P of the interdigital transducer 2.
The structure of the portions R _1m and R _2m is similar to the structure shown in FIG. Figure 13 is an enlarged plan view of a portion Q _1. Angle -β electrode finger portions Q ₁ is to the electrode fingers of the interdigital electrodes 2
With a slope of In the present embodiment, the inclination is −β as described above, but the inclination may be + β. The cycle length P _QN of the electrode finger in the direction orthogonal to the electrode finger of the portion Q ₁
Is equal to the product of the electrode period length P and cosβ. The electrode cross width of the portion Q _1, cross width in the direction of the electrode finger portions Q ₁ L _QP
And the intersection width L in a direction parallel to the electrode fingers of the IDT 2
There are two types, _QN . The intersection width L _QP is equal to the intersection width L _QN and sec.
It is equal to the product of β and the product of the value (P / 4) obtained by dividing the electrode period length P by 4 and cosec β. The portion R _1a, R _1b, R _2a and R _2b each electrode crossing width (3
mm) and the intersection width L of each of the portions R _1m and R _2m
The sum of _RN (1 mm) and the intersection width L _QN (1 mm) of the portion Q ₁ is equal to the electrode intersection width L (15 mm) of the IDT 2. When driving the ultrasonic touch panel of the fourth embodiment of FIG. 11, the circuit configuration of FIG. 4 is used. However, FIG.
The IDT 3 is replaced by an IDT 11. The elastic waves excited on the piezoelectric substrate 1 by inputting an electric signal from the interdigital electrode 2 generate portions R _1a , R _1b , R
By _2a and R _2b, the frequency f _1a, f _1b, the electric signal E _1a having f _2a and f _2b, E _1b, are respectively converted into E _2a and E _2b. The amplitude of the electric signal generated by synthesizing the electric signals E _1a and E _1b and the amplitude of the electric signal generated by synthesizing the electric signals E _2a and E _2b are both zero. The interdigital transducers 2 and 11 are formed on the piezoelectric substrate 1 by the ultrasonic wave propagation paths Z _1a , Z _1b , Z _2a and Z _2b corresponding to the portions R _1a , R _1b , R _2a and R _2b, respectively.
To form If the position F _1b , F _1a , F _2b or F _2a is brought into contact with the upper end surface or the lower end surface of the piezoelectric substrate 1, the electric signals E _1a , E _1b , E _1b having the frequencies f _1a , f _1b , f _2a or f _2b are obtained. E _2a or E _2b is detected by the signal processor 5. Thus, from the frequency of the electric signal detected by the signal processor 5, it can be determined which of the positions F _1a , F _1b , F _2a and F _2b has been touched. In addition, the contact position with respect to the ultrasonic wave transmitting / receiving means X and the contact position with respect to the ultrasonic wave transmitting / receiving means Y are simultaneously detected. In the ultrasonic touch panel according to the fourth embodiment, each ultrasonic wave transmitting / receiving means has a structure including four interdigital electrodes 2 and four corresponding interdigital electrodes 11, that is, the interdigital electrode 3 in FIG. A structure in which the shape electrode 11 is replaced is possible. When driving an ultrasonic touch panel having such a structure, the circuit configuration shown in FIG. 8 is used. However, the IDT 3 in FIG. 8 is replaced with an IDT 11. The elastic waves excited on the piezoelectric substrate 1 by inputting an electric signal from the interdigital electrode 2 through the switch 6 are subjected to frequencies f _1a , f _1b , f by the portions R _1a , R _1b , R _2a and R _2b . _2a and f _2b
Are converted into electric signals E _1a , E _1b , E _2a and E _2b , respectively. Positions F _1b , F _1a , F _2b located between one interdigital electrode 2 in the ultrasonic wave transmitting / receiving means X and the corresponding interdigital electrode 3 on the upper end surface or the lower end surface of the piezoelectric substrate 1. _{Alternatively} , when F _2a is touched, the electric signals E _1a , E _1b , E _2a or E _2b are detected by the signal processor 5. In this manner, the contact position is clarified by discriminating the frequency of the electric signal detected by the signal processor 5 and the only interdigital transducer 2 connected when the electric signal was detected. The same applies to the ultrasonic wave transmitting / receiving means Y. In the ultrasonic touch panel according to the fourth embodiment, each of the ultrasonic wave transmitting and receiving means includes reference interdigital electrodes 7 and 8, four interdigital electrodes 2 and four corresponding interdigital electrodes 2.
A structure composed of two interdigital electrodes 11, that is, a structure in which the interdigital electrode 3 of FIG. When driving an ultrasonic touch panel having such a structure, the circuit configuration shown in FIG. 10 is used. However,
The IDT 3 in FIG. 10 is replaced by an IDT 11. The elastic wave excited by the piezoelectric substrate 1 by inputting an electric signal from the interdigital transducer 2 through the switch 6 has phases θ _1a , θ _1b , θ _2a depending on the portions R _1a , R _1b , R _2a and R _2b . Or electric signals E _1a , E having θ _2b
1b , E _2a or E _2b respectively. Positions F _1b , F _1a , F _2b located between one interdigital electrode 2 in the ultrasonic wave transmitting / receiving means X and the corresponding interdigital electrode 3 on the upper end surface or the lower end surface of the piezoelectric substrate 1. Or F _2a , the electric signals E _1a , E _1b , E _2a or E _2
2b is output from the interdigital electrode 3. At this time, the phase comparator 10 detects a difference between the phase θ _{base of the} electric signal output from the interdigital transducer 8 and the phase θ _1a , θ _1b , θ _2a or θ _2b . The signal processor 5 identifies the contact position by discriminating the phase difference and the only interdigital transducer 2 connected when the phase difference is detected. The same applies to the ultrasonic wave transmitting / receiving means Y. FIG.
FIG. 9 is a plan view showing a fifth embodiment of the ultrasonic touch panel of the present invention. This embodiment has a structure in which the input IDT 2 and the output IDT 3 of FIG. 1 are replaced with the input IDT 12 and the output IDT 13. FIG. 15 is a diagram showing the relative structure between the interdigital electrodes 12 and 13. The IDTs 12 and 13 are 1
It has zero pairs of electrode fingers. The intersection area of the electrode fingers of the interdigital electrode 12 is composed of two portions A ₁ and A ₂ and one portion B ₁ , and the portion B ₁ is between the portions A ₁ and A ₂ . The intersecting region of the electrode fingers of the interdigital electrode 13 is composed of three parts C ₁ , C ₂ and C ₃ and two parts D ₁ and D ₂ , and the part D ₁ is composed of the parts C ₁ and C ₂ Part D ₂
Is between the portions C ₂ and C ₃ . The directions of the electrode fingers of the portions A ₁ and A ₂ are parallel to the directions of the electrode fingers of the portions C ₁ , C ₂ and C ₃ . Parts A ₁ , A ₂ , C ₁ ,
The electrode cycle length P of each of C ₂ and C ₃ is 1.7 mm. Figure 16 is an enlarged plan view of a portion B _1. Has a slope portion B ₁ of the electrode fingers is angular relative to portion A ₁ and the electrode fingers of the A _2-beta, the period length P _BN electrode fingers in a direction perpendicular to the electrode fingers of the portion B _1, the electrode period Equal to the product of length P and cosβ. The electrode cross width of the portion B _1, and overlap length L _BP in the direction of the electrode finger portion B _1, are two types of cross width L _BN in the direction parallel to the electrode fingers of the portions A ₁ and A ₂ is there. The intersection width L _BP is the intersection width L
Equal to the product of _BN and secβ. Further, the intersection width L _BP is equal to the product of the value (P / 4) obtained by dividing the electrode cycle length P by 4 and cosec β. Figure 17 is an enlarged plan view of a portion D _1. Portion D ₂ also form the same structure as the part D _1. Portion D ₁ of the electrode fingers has a slope portion C _1, C ₂ and angular to the electrode fingers of C ₃ alpha, the period length P _DN of the electrode fingers in a direction perpendicular to the electrode fingers of the part D _1, It is equal to the product of the electrode period length P and cosα. The electrode cross width of the portion D _1, and the overlap length L _DP in the direction of the electrode finger portion D _1, and part C _1, C ₂ and overlap length L _DN in the direction parallel to the electrode fingers of the C ₃ to There are two types. The intersection width L _DP is equal to the product of the intersection width L _DN and secα and equal to the product of half of the electrode period length P and cosec α. The same applies to the portion D2. The total (15 mm) of the electrode cross widths (7 mm) of the portions A ₁ and A ₂ and the cross width L _BN (1 mm) of the portion B ₁ is the electrode cross width (3 mm) of each of the portions C ₁ and C ₃ , The electrode intersection width (7 mm) of the portion C ₂ ,
Equal to the sum of partial D ₁ and D ₂ respectively overlap length _{L D N (1mm) (15mm} ). When driving the ultrasonic touch panel of the fifth embodiment of FIG. 14, the circuit configuration of FIG. 4 is used. However, the IDTs 2 and 3 in FIG. 4 are replaced with IDTs 12 and 13. The elastic wave excited on the piezoelectric substrate 1 by inputting an electric signal from the interdigital transducer 12 is converted into two electric signals E _1a and E _2a and two electric signals E _1b and E _2b by the interdigital transducer 13.
Is converted to The amplitude of the electric signal generated by combining the electric signals E _1a and E _1b becomes zero, and the electric signal E _2a
And the amplitude of the electric signal generated by combining E _2b becomes zero. The IDTs 12 and 13 are formed on the piezoelectric substrate 1 by two ultrasonic wave propagation paths Z _1a and Z _2a ,
The ultrasonic propagation paths Z _1b and Z _2b are formed. The ultrasonic wave propagation path Z _1a is between the parts A ₁ and C ₁ , the ultrasonic wave propagation path Z _1b is between the parts A ₁ and C _2, and the ultrasonic wave propagation path Z _2a is between the parts A ₂ and C ₂ . , The ultrasonic wave propagation path Z _2b exists between the portions A ₂ and C ₃ respectively. If the position F _1b , F _1a , F _2b or F _2a is brought into contact with the upper end surface or the lower end surface of the piezoelectric substrate 1, the electric signals E _1a , E _1b , E _1b having the frequencies f _1a , f _1b , f _2a or f _2b are obtained. E _2a or E _2b is detected by the signal processor 5. At this time, the position F _1b , F _1a , F _2b or F
_2a never electrical signal converted by the portion D ₁ and D ₂ are output or may not contact the. In this way,
From the frequency of the electric signal detected by the signal processor 5, it can be determined which of the positions F _1a , F _1b , F _2a and F _2b has been touched. Moreover, the contact position with respect to the ultrasonic wave transmitting / receiving means X,
The contact position with respect to the ultrasonic wave transmitting / receiving means Y is simultaneously detected. In the ultrasonic touch panel of the fifth embodiment, each ultrasonic wave transmitting / receiving means has a structure including four interdigital electrodes 12 and four corresponding interdigital electrodes 13, that is, the interdigital electrodes 2 and 3 in FIG. Blind electrode 12
And 13 are possible. When driving an ultrasonic touch panel having such a structure, the circuit configuration shown in FIG. 8 is used. However, the interdigital electrodes 2 and 3 in FIG. 8 are replaced with the interdigital electrodes 12 and 13.
The elastic wave excited in the piezoelectric substrate 1 by inputting an electric signal from the interdigital electrode 12 through the switch 6 causes two electric signals E _1a and E _2a by the interdigital electrode 13.
And two electric signals E _1b and E _2b . On the upper end surface or the lower end surface of the piezoelectric substrate 1, positions F _1b , F _1a , F _1a , F _1a , which are located between one interdigital electrode 12 in the ultrasonic wave transmitting / receiving means X and the corresponding interdigital electrode 13.
When F _2b or F _2a is touched, the electric signals E _1a , E _1b , E
_2a or E _2b is detected by the signal processor 5. Thus, the frequency of the electric signal detected by the signal processor 5 and
By determining only one interdigital electrode 12 that was connected when the electric signal was detected, the contact position becomes clear. The same applies to the ultrasonic wave transmitting / receiving means Y. Also, in the ultrasonic touch panel of the fifth embodiment, each ultrasonic wave transmitting / receiving means is constituted by the reference interdigital electrodes 7 and 8, the four interdigital electrodes 12, and the four corresponding interdigital electrodes 13. That is, a structure in which the interdigital electrodes 2 and 3 in FIG. 9 are replaced with the interdigital electrodes 12 and 13 is possible. When driving an ultrasonic touch panel having such a structure, the circuit configuration shown in FIG. 10 is used. However, the IDTs 2 and 3 in FIG. 10 are replaced with IDTs 12 and 13. The elastic wave excited by the piezoelectric substrate 1 by inputting an electric signal from the interdigital transducer 12 through the switch 6 is applied to the interdigital transducer 13.
Electrical signals having a phase theta _1a by E _1a and phase theta _2a
Signal E _2a having phase θ _1b and electric signal E ₂ having phase θ _1b
It is converted into an electric signal E _2b having _1b and a phase θ _2b .
On the upper end surface or lower end surface of the piezoelectric substrate 1, positions _F1b and F1 between one interdigital electrode 12 and the corresponding interdigital electrode 13 in the ultrasonic wave transmitting / receiving means X are provided.
_1a , F _2b or F _2a , the electrical signals E _1a ,
E _1b , E _2a or E _2b is output from the interdigital electrode 13. At this time, the phase comparator 10 uses the IDT 8
A phase theta _base of the electrical signal output from the phase theta _1a, theta
The difference from _1b , θ _2a or θ _2b is detected. Signal processor 5
Specifies the contact position by discriminating this phase difference and the only interdigital transducer 12 connected when this phase difference was detected. The same applies to the ultrasonic wave transmitting / receiving means Y. In the ultrasonic touch panels of the first to fifth embodiments, the electrode period length P of the input-side interdigital electrodes 2, 7, and 12 is 400 μm, and the output-side interdigital electrodes 3, 8,.
Structures where 11 and 13 have corresponding electrode period lengths are possible. In this case, when an electric signal having a frequency substantially corresponding to the electrode period length P is input from the input IDT, a surface acoustic wave having a wavelength substantially equal to the electrode period length P is generated near the surface of the upper end surface of the piezoelectric substrate 1. Excited. In an ultrasonic touch panel using such a surface acoustic wave, the position is specified by contacting the upper end surface of the piezoelectric substrate 1.

The ultrasonic touch panel of the present invention has a piezoelectric substrate, two ultrasonic transmitting / receiving means provided on one plate surface of the piezoelectric substrate, and an information processing connected to the two ultrasonic transmitting / receiving means. Consisting of parts. Each ultrasonic wave transmitting / receiving means comprises at least one set of input IDTs and output IDTs corresponding to the input IDTs. In the first structure of the ultrasonic touch panel of the present invention, the input IDT has a regular structure. The intersecting region of the electrode fingers of the output IDT consists of only one group R _i (i = 1) or N groups R _i (i = 1, 2,...,
N) and two groups R _i and R _{(i + 1)} (N
−1) pieces Q _i {i = 1, 2,..., (N−1)}
Consists of Each group R _i has two parts R _ia and R _ib
And a portion R _im sandwiched between them. If an electric signal is inputted to the input IDT, ultrasonic waves are excited on the piezoelectric substrate. The ultrasonic waves are converted into electric signals E _ia and E _ib (i = 1, 2,..., N) by the portions R _ia and R _ib .
Respectively. At this time, the amplitude of the electric signal generated by combining the electric signals E _ia and E _ib becomes zero. The input and output IDTs form ultrasonic propagation paths Z _ia and Z _ib (i = 1, 2,..., N) corresponding to the portions R _ia and R _{ib on} the piezoelectric substrate. If the position F _ia or F
_{When ib} (i = 1, 2,..., N) is brought into contact, the ultrasonic wave propagation path Z _ia or Z _ib is cut off, and the electric signal E _ib or E _ia
Is output from the output IDT. The information processing unit
That contacts the position F _Xa, position F constituting the position F _Xa paired
An electric signal _EXb corresponding to _Xb is sensed by being output from the output IDT. Similarly, the contact with the position F _Xb is sensed by outputting the electric signal _Exa corresponding to the position F _Xa from the output IDT.
In this manner, the ultrasonic touch panel of the present invention can output the electric signal E _ib or E _ia only when the ultrasonic touch panel contacts the position F _ia or F _ib . In the second structure of the ultrasonic touch panel according to the present invention, the intersection area of the electrode fingers of the input IDT has N portions A _i (i = 1, 2, 2).
.., N) and (N−1) parts B _i ｛i = 1, 2,..., (N− ₎ sandwiched between two parts A _i and A _{(i + 1)}
1)}, and the intersecting area of the electrode fingers of the output IDT includes (N + 1) parts C _i ｛i = 1, 2,.
(N + 1)} and N portions D _i (i = 1, 2,..., N) sandwiched between two portions C _i and C _{(i + 1)} .
If an electric signal is inputted to the input IDT, ultrasonic waves are excited on the piezoelectric substrate. The ultrasonic waves are output by the output IDT electrodes into N electrical signals E _ia (i = 1, 2,...).
.., N) and N electric signals E _ib (i = 1, 2,...)
.., N). The amplitude of the electric signal generated by combining the electric signals E _ia and E _ib becomes zero. The input and output IDTs are N
_.. , N) and N ultrasonic propagation paths Z _ib (i = 1, 2,..., N). Ultrasonic propagation path Z _ia between parts A _i and C _i, ultrasonic propagation path Z _ib is between parts A _i and C _{(i + 1).} If,
Position F _ia or F _{ib on the} piezoelectric substrate (i = 1, 2,...)
, N), the ultrasonic wave propagation path Z _ia or Z _ib is cut off, and the electric signal E _ib or E _ia is output from the output IDT. Information processing section that contacts the position F _Xa, is sensed by the electric signal E _Xb corresponding to the position F _Xb forming position F _Xa and pair is outputted from the output interdigital transducer. Similarly, the contact with the position F _Xb is sensed by outputting the electric signal _Exa corresponding to the position F _Xa from the output IDT. In this manner, the ultrasonic touch panel of the present invention can output the electric signal E _ib or E _ia only when the ultrasonic touch panel contacts the position F _ia or F _ib . In the ultrasonic touch panel of the present invention, the contact position F _ia or F _ib is determined by the output electric signal E.
It can be specified by the frequency f _ib or f _ia of _ib or E _ia respectively. In this case, the information processing unit includes a signal processor, the signal processor identifies by detecting the frequency f _Xb of the electrical signal E _Xb contact position F _Xa, frequency of contact position F _Xb electrical signal E _Xa It is specified by detecting f _Xa . Ultrasonic touch panel of the present invention, the contact position F _ia or F _ib, and an output electric signal E _ib or E _ia each phase theta _ib or theta _ia, be identified from the difference between the phase theta _base as a reference Is possible. In this case, the information processing unit includes a phase comparator and a signal processor,
Each ultrasonic transmitting and receiving means includes two reference IDTs. When an electric signal is input to one of the reference IDTs, an ultrasonic wave is excited on the piezoelectric substrate, and the ultrasonic wave is converted into an electric signal having a phase θ _base by the other IDT and output. The phase comparator calculates the phase difference (θ _base -θ _ia ) or the phase difference (θ _base -θ
_ib ) to detect. Signal processor is a contact position F _Xa specified based on the phase difference (θ _base -θ _Xb), is identified based on the contact position F _Xb to the phase difference (θ _base -θ _Xa). In the ultrasonic touch panel of the present invention, a structure in which the electrode cycle length P is larger than the thickness d of the piezoelectric substrate is possible. In this case, an elastic wave is excited on the piezoelectric substrate. In a device using such an elastic wave, when a position F _ia or F _ib on one of the plate surfaces of the piezoelectric substrate is brought into contact, an electric signal E _ib or E _ia is generated. In the ultrasonic touch panel of the present invention,
A structure in which the electrode period length P has a value equal to or less than one third of the thickness d of the piezoelectric substrate is possible. In this case, a surface acoustic wave is excited in the vicinity of the surface of the piezoelectric substrate having the interdigital electrodes. In a device using such a surface acoustic wave, when the position F _ia or F _ib on the plate surface of the piezoelectric substrate having the interdigital electrodes is brought into contact, an electric signal E _ib or E _ia is generated. In the ultrasonic touch panel of the present invention,
By adopting a structure in which a piezoelectric ceramic is used as the piezoelectric substrate and the direction of the polarization axis of the piezoelectric ceramic is parallel to the direction of the thickness d, a device excellent in design easiness can be provided. . In the ultrasonic touch panel of the present invention, the ultrasonic wave propagation path in one ultrasonic wave transmitting / receiving means and the ultrasonic wave propagation path in the other ultrasonic wave transmitting / receiving means are orthogonal to each other, so that those propagation paths are orthogonal to each other. Can be represented by two-dimensional coordinates where X is the X axis and Y axis, respectively.

[Brief description of the drawings]

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

FIG. 2 is a diagram showing a relative structure between interdigital electrodes 2 and 3;

FIG. 3 is an enlarged plan view of a portion R _1m .

FIG. 4 is a circuit configuration diagram of the ultrasonic touch panel of FIG. 1;

FIG. 5 is a characteristic diagram showing a relationship between a k ² value calculated from a phase velocity difference of the piezoelectric substrate 1 under two different electrical boundary conditions and an fd value.

FIG. 6 is a characteristic diagram showing a velocity dispersion curve of an elastic wave propagating through the piezoelectric substrate 1.

FIG. 7 is a plan view showing a second embodiment of the ultrasonic touch panel of the present invention.

FIG. 8 is a circuit configuration diagram of the ultrasonic touch panel of FIG. 7;

FIG. 9 is a plan view showing a third embodiment of the ultrasonic touch panel of the present invention.

FIG. 10 is a circuit diagram of the ultrasonic touch panel of FIG. 9;

FIG. 11 is a plan view showing a fourth embodiment of the ultrasonic touch panel according to the present invention.

FIG. 12 is a diagram showing a relative structure between the IDTs 2 and 11;

FIG. 13 is an enlarged plan view of a part Q _1.

FIG. 14 is a plan view showing a fifth embodiment of the ultrasonic touch panel of the present invention.

FIG. 15 is a diagram showing a relative structure between the interdigital electrodes 12 and 13;

Figure 16 is an enlarged plan view of a portion B _1.

Figure 17 is an enlarged plan view of a portion D _1.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Piezoelectric substrate 2,12 IDT for input 3,11,13 IDT for output 4,9 Amplifier 5 Signal processor 6 Switch 7,8 IDT for reference 10 Phase comparator

Claims (10)

[Claims] 1. An ultrasonic touch panel comprising a piezoelectric substrate, two ultrasonic wave transmitting / receiving means provided on one plate surface of the piezoelectric substrate, and an information processing unit connected to the two ultrasonic wave transmitting / receiving means. Wherein each of the ultrasonic wave transmitting and receiving means comprises at least one set of input IDTs, and output IDTs corresponding to the input IDTs, and The intersection region consists of one group R _i (i = 1) or N groups R _i (i = 1, 2,..., N) and the two groups R _i and R _{(i +} sandwiched between ₁₎ (N-1) number of partial Q _i
{I = 1,2, ......, ( N-1)} consists, each group R _i comprises two portions R _ia and R _ib, from a portion sandwiched by R _{i m} to, the moiety R The directions of the electrode fingers of _ia and R _ib are parallel to the directions of the electrode fingers of the input IDT, and the electrode cycle lengths of the portions R _ia and R _ib are the electrode _pitch P of the input IDT. equally, the moiety R electrode fingers of _im has an inclination of angle α with respect to the electrode fingers of said input interdigital transducer, said portion R periodicity P _RN electrode fingers in a direction perpendicular to the electrode fingers of the _im It is equal to the product of the electrode periodicity P and cos [alpha], wherein the electrode crossing width of the portion R _im, and overlap length L _RP in the direction of the electrode fingers of the part R _im, of the input interdigital transducer There are two types, an intersection width L _{RN in} a direction parallel to the electrode finger, and the intersection width L _RP is equal to the intersection width L _RN and secα. And the same as the product of half of the electrode period length P and cosec α, and the electrode finger of the portion Q _i has an inclination of ± β with respect to the electrode finger of the input IDT; periodicity P _QN of the electrode fingers in a direction perpendicular to the electrode fingers of the part Q _i is equal to the product of the electrode periodicity P and cos .beta, the electrode crossing width of the portion Q _i, the portion Q _i and overlap length L _QP in the direction of the electrode fingers, there are two types of cross width L _QN in the direction parallel to the electrode fingers of said input interdigital transducer, the overlap length L _QP is the overlap length L _QN The sum of the electrode cross widths of the portions R _ia and R _ib , the cross width L _RN, and the cross width L _QN is equal to the electrode cross width L of the input IDT. Almost equal, the input IDT excites an ultrasonic wave to the piezoelectric substrate by receiving an electric signal, The portions R _ia and R _{ib convert the} ultrasonic waves into electrical signals E _ia
, And E _ib (i = 1, 2,..., N), respectively, and the amplitude of the electric signal generated by combining the electric signals E _ia and E _ib is zero. In the piezoelectric substrate, the ultrasonic electrodes Z _ia and Z _ib (i = 1, 2,..., N) corresponding to the portions R _ia and R _ib, respectively.
And positions F _ia and F _ib (i = 1, 1) on the piezoelectric substrate.
,..., N) respectively correspond to the ultrasonic wave propagation paths Z _ia and Z _ib , and the output interdigital transducer is configured such that a human finger or an object comes into contact with the position F _ia or F _ib and the ultrasonic wave Only when the propagation path Z _ia or Z _ib is cut off, outputs the electric signal E _ib or E _ia , and the information processing unit contacts one of the positions F _ia F _Xa , that electrical signals E _Xb corresponding to the position F _Xb forming the position F _Xa and pairs or sensed by output from interdigital electrode the output, or in contact with the position F _Xb, the position F _Xa An ultrasonic touch panel that senses when an electric signal _EXa corresponding to the output is output from the output IDT. 2. The ultrasonic touch panel according to claim 1, wherein the intersection width L _QP is equal to a product of a value obtained by dividing the electrode cycle length P by twice the number N of the groups R _i and cosec β. 3. An ultrasonic touch panel comprising a piezoelectric substrate, two ultrasonic transmitting / receiving units provided on one plate surface of the piezoelectric substrate, and an information processing unit connected to the two ultrasonic transmitting / receiving units. Wherein each of the ultrasonic wave transmitting and receiving means comprises at least one set of input IDTs, and output IDTs corresponding to the input IDTs. The intersection area is composed of N parts A _i (i = 1, 2,..., N) and (N−1) parts B sandwiched between the two parts A _i and A _{(i + 1).
i} {i = 1, 2,..., (N−1)}, and the intersection area of the electrode fingers of the output IDT is (N +
1) parts C _i {i = 1, 2,..., (N + 1)}
And N portions D _i (i = 1, 2,..., N) sandwiched between the two portions C _i and C _{(i + 1),} and the direction of the electrode finger of the portion A _i is In parallel with the direction of the electrode finger of the portion C _i, the electrode finger of the portion B _{i has} an angle − with respect to the electrode finger of the portion A _i.
has a slope of β, and the period length P _BN of the electrode finger in the direction orthogonal to the electrode finger of the portion B _i is equal to the product of the electrode period length P of the portions A _i and C _i and cos β; the electrode cross width of the portion B _i, the overlap length L _BP in the direction of the electrode fingers of the portion B _i, there are two types of cross width L _BN in a direction parallel to the electrode fingers of the part a _i , The intersection width L _BP
Equal to the product of the overlap length L _BN and secβ, the portion D _i is the electrode finger the part C corner to the electrode fingers of the _i alpha
Has a slope, periodicity P _DN of the electrode fingers in a direction perpendicular to the electrode fingers of the part D _i is equal to the product of the electrode periodicity P and cos [alpha], the electrode crossing width of the portion D _i , the portion D and the overlap length L _DP in the direction of the _i electrode fingers of, there are two types of cross width L _DN in a direction parallel to the electrode fingers of the portions C _i, the overlap length L _DP
Is equal to the product of the intersection width L _DN and secα,
It is equal to the product of half of the electrode cycle length P and cosec α, and the sum of the electrode finger intersection width and the intersection width L _BN of the portion A _{i is} the electrode finger intersection width and the intersection width L of the portion C _i. Almost equal to the sum of _DN, the input IDT excites an ultrasonic wave to the piezoelectric substrate by receiving an electric signal, and the output IDT transmits the ultrasonic wave to N electric signals. E _ia (i = 1, 2,..., N) and N electric signals E _ib (i = 1, 2,..., N), and combining the electric signals E _ia and E _ib Is zero, and the input and output IDTs are provided on the piezoelectric substrate by N ultrasonic wave propagation paths Z _ia (i = 1, 2,...).
.., N) and N ultrasonic propagation paths Z _ib (i = 1, 2, 2)
.., N), the ultrasonic wave propagation path Z _ia is between the parts A _i and C _i , and the ultrasonic wave propagation path Z _ib is between the parts A _i and C _{(i + 1)} . And positions F _ia and F _{ib on the} piezoelectric substrate (i = 1,
,..., N) respectively correspond to the ultrasonic wave propagation paths Z _ia and Z _ib , and the output interdigital transducer is configured such that a human finger or an object comes into contact with the position F _ia or F _ib and the ultrasonic wave Only when the propagation path Z _ia or Z _ib is cut off, outputs the electric signal E _ib or E _ia , and the information processing unit contacts one of the positions F _ia F _Xa , that electrical signals E _Xb corresponding to the position F _Xb forming the position F _Xa and pairs or sensed by output from interdigital electrode the output, or in contact with the position F _Xb, the position F _Xa An ultrasonic touch panel that senses when an electric signal _EXa corresponding to the output is output from the output IDT. 4. The ultrasonic touch panel according to claim 3, wherein the intersection width L _BP is equal to a product of a value obtained by dividing the electrode cycle length P by twice the number N of the portions A _i and cosec β. 5. The information processing unit comprises an amplifier and a signal processor, and an output terminal of the output IDT is connected to an input terminal of the input IDT and an input of the signal processor via the amplifier. The electric signals E _ia and E _ib have frequencies f _ia and f _ib , respectively, and the signal processor detects the contacted position F _Xa and the frequency f _Xb of the electric signal _EXb Or by identifying
4. The method according to claim 1, wherein the touched position F _Xb is specified by detecting a frequency f _Xa of the electric signal E _Xa.
Or the ultrasonic touch panel according to 4. 6. The ultrasonic wave transmitting and receiving means includes two reference interdigital transducers, one of the reference interdigital transducers being used for input and the other being used for output; The directions of the electrode fingers of the interdigital transducer are parallel to each other, the information processing unit includes an amplifier, a phase comparator, and a signal processor.The output terminal of the other reference interdigital transducer is, via the amplifier, The one reference IDT and the input IDT are connected to the input terminals of the input IDT, and the input terminal of the phase comparator is connected to the output terminal of the output IDT. The one of the reference IDTs is connected to an input terminal of the signal processor via an input terminal, and the one of the reference IDTs receives an electric signal to excite ultrasonic waves to the piezoelectric substrate, and the other of the reference IDTs. The pole converts the ultrasonic wave into an electric signal having a phase θ _base and outputs the electric signal. The electric signals E _ia and E _ib have phases θ _ia and θ _ib , respectively, and the phase comparator outputs the phase θ _base , and a difference between the phase θ _ia or θ _ib is detected, and the signal processor determines the contacted position F _Xa as the phase θ
_The position F _Xb is specified based on the difference between the _base F and the phase θ _Xb of the electric signal E _Xb , or the contacted position F _Xb is determined based on the phase θ _Xb.
The ultrasonic touch panel according to claim 1, wherein the identification is performed based on a difference between a _base and a phase θ _Xa of the electric signal _EXa . 7. The electrode period length P is greater than the thickness d of the piezoelectric substrate, and the input IDT is supplied with an electric signal having a frequency substantially corresponding to the electrode period length P. 7. The ultrasonic touch panel according to claim 1, wherein an elastic wave having a wavelength substantially equal to the electrode cycle length P is excited on the piezoelectric substrate. 8. The electrode period length P has a value equal to or less than one third of the thickness d of the piezoelectric substrate, and the input IDT has an electric frequency having a frequency substantially corresponding to the electrode period length P. A signal is input to excite a surface acoustic wave having a wavelength substantially equal to the electrode period length P near the surface of the one plate surface of the piezoelectric substrate. 7. The ultrasonic touch panel according to 6. 9. The piezoelectric substrate is made of a piezoelectric ceramic,
The direction of the polarization axis of the piezoelectric ceramic is parallel to the thickness direction of the piezoelectric ceramic.
9. The ultrasonic touch panel according to 6, 7, or 8. 10. One of the said at ultrasonic transmitter means and an ultrasonic propagation path Z _ia and Z _ib, wherein the other of said ultrasonic transmitter means ultrasonic propagation path Z _ia and Z
_ib is orthogonal to each other.
10. The ultrasonic touch panel according to 6, 7, 8 or 9.