JPS60138431A - Surface sound wave sensor - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates generally to a sensor for measuring pressure using surface sound waves, and more particularly to a highly stable and well-suited sensor for measuring high pressures using surface sound waves. Sensors using surface acoustic wave (SAW) devices such as delay lines and resonators with low sensitivity are known for measuring acceleration, stress and strain, and pressure. These sensors are generally based on the propagation of surface sound waves across a thin, flexible diaphragm that deforms when subjected to acceleration, stress, strain, or pressure.The velocity and path length of the surface sound waves depend on the diaphragm's Since it sharpens with deformation, the delay time of the surface sound wave is a function of externally applied acceleration, stress or strain, or pressure.Changes in the propagation characteristics of the surface sound wave are caused by the SA in the regenerative feedback loop.
It is measured as a change in the oscillation frequency of an external oscillation circuit connected in series with the W device.

Reader et al., U.S. Pat. No. 3,978,731, issued September 7, 1976;
US Pat. No. 3,863,497 issued by van de Vaart et al.
A W sensor is disclosed.

Methods for manufacturing pressure-sensitive diaphragms for SAW sensors are well known. A sensor with a piezoelectric transducer attached to a steel beam by thin film technology
No. 4,107,626, issued on August 15, 1978, to Mr. In 1980, a sensor having two substrates with the same thickness and bonded in the same orientation to each other, a SAW substrate and a pace substrate, was developed.
Wagner U.S. Patent No. 4.21, dated August 5,
It has been disclosed in No. 6.401. Such sensors either have severe limitations in their operating characteristics or may actually malfunction due to reduced performance due to bonding constraints.

Alternatively, a pressure sensitive diaphragm may be formed by drilling a central hole 91jl#l in a 5AW unit, as disclosed, for example, in US Pat. No. 4,100,811 to Callen et al., issued July 180, 1978. Although this solution eliminates the need for bonding in the sensing area, this type of perforated diaphragm is easy to make to the desired thickness or very thin, and the membrane planes can be made parallel. It's not easy either. Furthermore, the stress is concentrated in sharp and deep corners, which favors the sensor for low pressure applications.

A cylindrical pressure sensitive diaphragm that overcomes some of the problems described above is disclosed in U.S. Pat. No. 5,878,477 to Dlas et al., dated April 15, 1975. Each endcag is provided for admitting fluid to the interior of the diaphragm and making pressure measurements. However, such cylindrical diaphragms have the disadvantage that m-modification has a negative effect on pressure measurements.

In general, sensors using SAW devices that include a cylindrical pressure sensitive diaphragm as disclosed in the DIδS et al. patent are adversely affected by temperature changes. This advanced SAW device is
These generally include SAW substrates of piezoelectric materials such as quartz, lithium niobate, lithium tantalate, or composite treated substrates such as silicon with a suitable thin film of piezoelectric materials such as zinc oxide. All exhibit sufficient acoustic-electrical coupling to produce measurable changes in surface acoustic wave propagation velocity in response to changes in their subsurface fabric. These slopes are sensitive to strain-related phenomena, including temperature, stress, and acceleration.
The sensor must be equipped with a means to compensate for temperature changes or ST cut ((Vxwl) 0°
/42, 75°) My father has an SST cut ((yxwl)
0°/-49,22°, propagation direction is 26° from digonal thin
), if the direction of the hood compensation IA can be used,
Tokoshima temperature or H' must operate within a given narrow temperature range.

Several techniques are known for compensating for temperature changes in various types of sensors. The above mentioned lewlt
His patent states that waves propagate in adjacent regions of generally flat areas of the same water temperature, such that the effect of temperature changes on each region is equal to the actual and arranged widths. A conventional technique is disclosed: When a force is applied to the sensor, the output of each oscillator associated with each region - one region in compression and one region in tension is determined. By mixing, the difference in frequency is proportional to its deflection within the beam's elongation limits. 7) A temperature compensation technique is disclosed in which two connected sonic oscillators vary their respective frequencies inversely in response to forces applied perpendicular to the surface of the substrate.

The Re5der et al. patent described above discloses a temperature compensation ffJ technique in which the two acoustic channels of the sensor are formed in close proximity to each other on the same substrate of a generally flat diaphragm so that the temperature difference between them is reduced. is disclosed.

One channel is the main or measurement channel and the other channel is the reference channel. The pressure in the reference channel is held constant and the output of the 1tltl constant channel becomes a measure of absolute pressure after being mixed with the output of the reference channel. Dlar et al., U.S. Pat.
A device is disclosed in which a cut and on the other hand a rotation Y cut with R=35°) are connected in cascade to widen the temperature range of stable operation. Also, U.S. Pat. A sonic device is disclosed. The sound waves are propagated along a suitable path length to give a linear zero temperature coefficient of delay.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a sensing diaphragm suitable for measuring pressure and related phenomena.

This and other objects are achieved according to one aspect of the invention, comprising a crystalline diaphragm section with a cylindrical or spherical outer surface and a cylindrical or spherical inner surface, one of said outer and inner surfaces. is subjected to an applied pressure, and the other of said outer and inner surfaces has a first region having a selected orientation and is used to form a surface acoustic wave device; a second region facing in the same direction as the direction of the waveform and facing the formation of the surface acoustic wave device, said surface adapted to receive an applied pressure; a first portion of said diaphragm section between said surface and said second region having a first predetermined thickness; and said diaphragm section between said surface and said second region adapted to receive an applied pressure. The second portion is achieved by a surface wave signal frequency el& such that the second portion has a second predetermined thickness different from the first predetermined thickness. a crystalline diaphragm section having a shaped or spherical inner surface, said outer surface being adapted to receive a given isotropic force, and said inner surface being adapted to receive a region of selected crystal lattice configuration. This area is provided with a surface acoustic wave signal frequency cape, such as that used in surface wave devices (I).

Other objects, features and aspects of the present invention will become apparent from the following detailed description with reference to the accompanying drawings.

In the accompanying drawings, similar parts are designated by similar groove numbers.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The sensing diaphragm of the present invention comprises an internally loaded embodiment shown in FIGS. 1-3 and an externally loaded embodiment shown in FIGS. 4-5. A general description will be given of embodiments in which loads are applied. The ILR cold-sensing diaphragm of the present invention has a load on the outside and a load on the inside.
These devices are also well suited for pressure sensing and can be used to sense such phenomena as force and acceleration. The novel sensing diaphragm of the present invention spans a salinity range of e.g.
For temperatures of 75°C or higher, ha'! 1″0.01
High resolution of psi (0,0007 to 9 to 2) or better, full scale accuracy of yo, ozs9 or more, fast response time of V20 seconds or more, 106 or more, with good short-term frequency stability of y∆f/f = 11-IQ for dirt times of 1 second or more, and so ∆f/f = 10''67 0 psl to 8 * 000 with good knee song characteristics with good long term frequency stability of 2000 or more years.
ps 1 (30.000 ps in an embodiment that senses pressure in the range of 560 kg/(-”In2) and consists of
(210□ Kg/1x2) or more. The principle of operation, a suitable pressure housing and a suitable electrical circuit are described below. Figures 1 to 3. In the internally loaded embodiment shown in FIG.
Two longitudinal planes 2a and 2b are provided, which planes are preferably formed on the outer surface of the phantom cylinder +tl, but are not necessarily opposite to each other, such that the planes 2a and 2b lie in each parallel plane. It doesn't have to be. Each plane 2
a and 2b are milled to a depth r.

Although only a single plane is required, the use of two similarly cut opposing planes provides mechanical symmetry and has other effects as described below. A hole 4 is formed in the cylinder 1, and the axes of the hole 4 and the cylinder coincide with each other. The structural components of the diaphragm shown in Figures 1 to 3 and of the other internally loaded diaphragm embodiments described below are as follows, unless otherwise indicated. Depending on the size, the type of material used, the type of SAW mounting used in the structure, the SAW
The dimensions, which are a function of the direction of propagation of the surface wave energy that determines the position of the device, and the specifications and conditions of the pressure sensor, shall be sized to suit the particular application. , direct 44'-, I Q I is the 26th morning,
The length #'L' is 65 cylinders. Each plane 2a and 2b has a width of 14 trms and a hardness of 21 trms. Hole 4 is located at 10 feet. The cutting depth rl is two degrees. The thickness tl -6mu - is determined by the position of the hole 4 and the depth rl at which each plane is cut.

The above dimensions apply to examples with internal loads and external loads.
The following description of a heavy-duty embodiment provides an example of a combination of dimensions suitable for a high-pressure diaphragm. The selection of dimensions is designed to reduce the thermal excavation of the structure while, for example, to quickly equilibrate temperature gradients. surface K per mass
N is kept relatively large, provides structural strength for high pressure operation, and provides relative stability to the fabrication and performance of the SAW equipment used.
This is done by balancing various relationships, such as accepting the conditions of With the above dimensions for the fruit #i1+ll with internal load, the cut plane of, for example, 14 corners x 21 tuna, will reduce the physical fringe of the diaphragm and the hysteresis of the working area of the plane Jθ while minimizing it sufficiently. However, the area required by the SAW device itself is 2IIIm x 10M or less, depending on the degree of production.

The diaphragms of this embodiment and the 1111 embodiment described herein, both internally loaded and externally loaded, are preferably made of a single piece of resilient piezoelectric material. Quartz has one of the lowest acoustic losses of the available earthen materials, a requirement for good short-term RDJ stability/medium-time stability of crystal controlled oscillators. Energy loss/unit volume/cycle and storage fjt elastic energy/unit volume/
If the ratio Δ to the cycle is the Q of the sound eaves, the Q of the crystal can be expressed as Q-1=72/r at a specific temperature and frequency, which means that the acoustic loss is inversely proportional to the speed of the propagating sound wave. It means to do. The product of Q and frequency (si 24 fsec) is approximately equal to 1013 for a surface wave in a crystal. The crystal must be a high-purity crystal (utL< is premium or optical grade crystal). Other suitable piezoelectric materials include lithium niobate, lithium tantalate, and silicon having a suitable thin film deposited on a composite treated substrate such as zinc oxide. In the cylindrical diaphragm embodiment, the predominant stress generated is hoop stress, which is significantly greater than axial stress.

The structural features and selected dimensions of the Divine Diaphragm embodiment described herein are 200 mm as measured in K"l.
It must give the sensor a very high Q of about 402 mm at MHz. For example, the 10 sections of the cylinder near the planes 2B and 2b are acted upon by the introduction of fluid into the hole 4 as a cs deforms sexually in response to the force exerted by it. These sections are far enough away from the ends of the diaphragm that the sensor's high Q
and force are efficiently combined. The elastic deformation of these sections is detected as a change in the zero frequency of the associated oscillator circuit, as defined below.

Although the SAW device W with the desired operating characteristics is preferably formed on a cut plane, it can also be formed on other contoured interfaces. For example, the SAW device and the propagation path can be combined on a curved surface, the SAW device can be formed on a flat surface and a portion of the propagation path can be placed on the curved surface, or the SAW device and the propagation path can be combined on a curved surface. Equipment curve L 77
: It can also be formed on a plane so that a part of the propagation path is provided on a flat plane. Additionally, the SAW device may be located on a plane that looks like a convergence line when the diaphragm is viewed in a cross-sectional IM view, or may be formed by a notch or an angular or curved channel appropriately made in the diaphragm. It may be in Sharp areas of planes, channels or notches may be smoothed to a desired degree to prevent stress concentrations from occurring.

For example, the operating characteristics, including temperature sensitivity Δf/fΔT and pressure sensitivity Δl/fΔP, depend on the orientation of the substrate that propagates the surface acoustic waves and the propagation direction of the surface acoustic waves (with respect to the trigonal axis in the direction rotated once). It was measured by
(hereinafter referred to as "γ"). in general,
The response of a particular oriented sAW device fr can be expressed by a two-dimensional polynomial in temperature and pressure as follows.

f (T, P) = Gotl) 10G, T + G2T + G, T' + ---+
G4P + G5P + G6P5+ ---+ G,
TP + G8T P -1-G, TP2+ ---The direction of the substrate is % In5 orientation of Radi.

Engineers & current 1nstltute o
f Electricaland Electronl
c Engineers, or 'IEEE', based on standards adopted by Ic, December 1949.
Proceedings of the Moon 1. Rl
E.

Published in 1378-1390 members of '5tand
ards on PleazaelectrlcCry
stals.

1949: 5 standard 49 IRE 14
, S1'', and is taken here for reference.Both the cutting part rotated once and the cutting part rotated twice are expressed as (y, xwl)Φ
/θ.

The crystal belongs to the trigonal system 1 international point group 32, class D3 (5choenfleas symbol), and has three directions (2π
/2 times) symmetry and three-way (3π/2 times) symmetry,
This is due to the symmetry of the crystal.

Φ=n(120°)±Φθ(n=0.1.2) and θ=θ. +m (180°) (m=+), 1) means that the directions are exactly the same.

In order to obtain a plane in the direction of one rotation, it is necessary to cut out the cylinder l from the crystal piece so that the longitudinal axis of the cylinder 1 and the X axis of the crystal piece are parallel to each other. In this case, only the selected rotating surface of plane 2a is cut to a depth r in a plane perpendicular to a line offset from the Y axis, and plane 2b
is cut to a depth of 1 t in a plane perpendicular to a line offset from the Y axis by the selected angle of rotation plus 1806. Since planes 2a and 2b are 180° apart from each other.

Their directions are the same (within the mechanical precision of the hollowing and cutting process) due to the three-way symmetry of the crystal.

Once planes 28 and 2b are ground, the surfaces are machined to form the SAW device. Considerable care should be taken in surface treatment and optical polishing to minimize the occurrence of inherent surface stress and the onset of minute cracks on the cut surface when a single load is applied to the probe structure. I have to pay. The above-mentioned original surface stress is caused by the unevenness of the surface cut by a machine, and SAW
This effect on the frequency characteristics of the SAW oscillator as the oscillator relaxes over time has a significant impact on the accuracy and stability of the pressure sensor KIff.

Suitable surface treatment and polishing techniques are known.

Techniques for suitably forming SAW delay lines or resonators in a plane are well known and will only be briefly described. SA,
W delay lines and resonators are particularly effective for use in the pressure sensor of the present invention. Surface sound waves can be propagated onto clear surfaces of crystalline solids.

The energy of such surface sound waves decays exponentially with depth in the parasite, with most of the wave energy being concentrated within one wavelength of the surface. Therefore, surface sound waves propagate substantially regardless of the conditions to which the opposite surface of the infested solid is exposed. Additionally, SAW delay lines and resonant S exhibiting a very large Q, about 100 times that of the equivalent electrical circuit, are conveniently used as feedback elements in crystal-controlled excavators.

Furthermore, the narrowband rjj characteristics of the SAW delay line and resonator allow more accurate resonant frequencies to be obtained.

A SAW delay line includes an array of input electrodes and an array of output electrodes disposed on the surface of a piezoelectric substrate. These electrode arrays are arranged along the surface of the substrate by en-P-fire (e
It is in the form of a linear array that delivers sonic energy in the nd flre ) direction. For example, in the pressure sensitive diaphragm embodiments of FIGS. 1-5, one surface wave delay line has an interdigital C-finger formed in plane 28 by, for example, standard photolithographic and thin film techniques. (in assembled form) transducers 6a (transmitter) and 88 (receiver). If self-induced noise unacceptably limits the short-term or long-term stability of the SAW device, U.S. Pat. No. 4,270.1 of Parker et al.
No. 05) K As disclosed, the electrode structure, in this case an interdigital transducer 68 and 8a%
Stability can be improved by adding a K-indentation.

Similarly, the second surface wave delay line comprises interdigital transducers 6b (transmitter) and 8b (receiver) formed in plane 2b; each transducer finger is separated by half a wavelength; The wavelength is selected taking into account the propagation speed of the piezoelectric material in the selected direction so that a wave of a predetermined frequency is generated. The width and bandwidth of the waves thus generated are determined by the number of finger pairs used in the array, and the bandwidth is inversely proportional to the number of fingers. The propagation direction r in the substrate is perpendicular to the finger of the interdigital transducer. The power angle, defined as the angle between the direction of energy flow and the wave vector, is the 5T-X
O for pure mode directions as in the case of cuts and SST cuts.

Conveniently, the SAW resonator may be replaced with a SAW delay line under certain conditions. 'SAW resonators use ion-ablated groups or reflective strips to form a resonant cavity with an electrode array in the center.

Manufacturing and practical issues associated with SAW delay lines and resonators were discussed in the May 1974 Ultrasonl.
M, F published on page 115 and page 126 of cs
.

'5surface Acoustic by Lewls
Wav@Devlcesand AppHcatlo
ns, Section 6, 0scllators--Th
e Next 5uccessful 5urface
AcoustlcWave Devlce'% and incorporated herein by reference May 1976, Pro
ceedlngs, of the l E E E.

Volume 64, No. 5, pages 711 to 721, and '5 surface-Acoustlc Wave' by T. B. II and R. C. M. Ll.
Rosonators'.

R1 The pressure sensitive diaphragm of the embodiment shown in FIGS. 5-5 is mounted within a suitable pressure housing and connected to a suitable electrical circuit. Another embodiment of the pressure-resistant I-Using, in which a load is applied inside, will be described below. An example Fi electronic circuit is shown in FIG. Oscillation n
Two measurement channels are shown: one containing excavator 203 m and counter 208a, and the other containing excavator 203b and counter 208b. The generators 203a and 203b are, for example, diaphragms 200 corresponding to the diaphragms in the embodiments of FIGS.
connected to. The oscillator 203a is a SAW device 2028
(This is for example plane 2 a s transmitter 6a and receiver 8
(corresponding to a SAW slow sail line consisting of a), broadband amplifiers 20 and 4a, and matching networks 206a and 213a connected in a feedback configuration. Oscillator 20
3b is the 9AW device 202b (this is, for example, the plane 2b
, a SAW delay line consisting of a transmitter 6b and a receiver 8b), a broadband amplifier 204b, and matching networks 206b and 213b connected in a feedback configuration.

Since the design of SAW oscillators is well known, only a brief description will be given here. One component of a SAW oscillator is a SAW delay line or resonator in the feedback path of a broadband amplifier. As the surface wave velocity changes, there is a corresponding change in the oscillation frequency that can be accurately measured. A properly designed SAW oscillator has the following characteristics:

(1) Loop gain exceeds net loss.

(2) The oscillation frequency must be within the passband of the interdigital transducer.

(3) The total phase shift around the loop must be an integral multiple of 2π.

The third requirement can be expressed as follows.

t φa f −1−= n (2+ v 2π where f is the center frequency of the SAW oscillator, ■ is the surface wave velocity with respect to the reference frame, 111 is the effective path length in the base fishing frame, and φa is It represents the phase shift in amplifiers, matching networks, and interdigital transducers, where nFi is an integer.The phase shift φa is generally a path length 1111/ This is negligible compared to the phase shift over C. The partial change in the eigenspeed variation is equivalent to the partial change in the oscillator frequency, ie.

It is. This is included here as a reference, September 1980 J, App1. Phys, 51 (4th of al.
5lnha published on pages 659 to 4665
&TlerSten's I On the Temper
ature Dependence of the Ve
location of 5 surface Wave in
Quartz”.

The frequency stability of a SAW oscillator, which is an important characteristic for accurately measuring pressure, is generally described in three areas. The three regions are the short-term region, which refers to stability over a period of seconds, especially from 1 second to 10 seconds.

The medium time domain refers to stability over many hours, and the long time domain refers to stability over many months or years. Short and medium time stability (F
M noise) is a part of the resolution and accuracy of the oscillator, and various means can be considered to minimize this noise. These measures include low-noise and low-gain amplifiers and low insertion loss and abrupt low 1. - selecting a SAW device with one frequency slope (group delay). Depending on the purpose of use, a SAW delay line or a SAW co-optation device may be selected for the excavator. Delay line structures are broadband in nature and are preferred when tunability and linearity are important, while co-camera structures have superior noise performance for narrow band applications. S.A.
In the W oscillator.

A frequency stability of at least 10-I+ is obtained for a gate time of 1 second. This is sufficient to provide the desired resolution and dynamic range for more accurate pressure measurements.

Various techniques for tuning SAW devices are known; for example, U.S. Pat.
．． No. 960. Various techniques are known for operating SAW devices at the fundamental frequency or at appropriate harmonic frequencies,1 for example, which are discussed here for reference19.
U.S. Patent No. 4.249 to Yen et al., dated February 3, 1981.
, No. 146.

Output f8 of excavator 203a and output f of excavator 203b
b is sent to each counter 208a and 208b, which each counts the frequency of their input signal and provides a digital representation thereof at the output to generate the oscillation 5.
The analog outputs of 203a and 203b are converted into digital signals. A sampling sequence is initiated by processor 207 which sends signals to counters 208a and 208b along lines 201 and 205 such that the outputs of excavators 203a and 203b are each sampled and the results are sent along input lines 211 and 212. will be sent. The digital signals representing fa and fb are sent to processor 207, which calculates the pressure measurements and records the results 5209 for display to the user.
and line 201 for the next measurement cycle.
and 205 to reset counters 208a and 208b, respectively.

Processor 207 performs either curve fitting routines or look-up tables and interpolation techniques to determine each pressure measurement from one of signals fa and fb or the average of signals fa and fb.

The pressure measured by the SAW-equipped MIVC as a function of frequency and temperature can be expressed by the following two-dimensional polynomial:〇ρ(flT)=Ho (41 +H, f+H2f2+1-13f5+...+H4T+
H5T2+H6T! l+...+H7f T+HB f
2 T+H1fT2 =...If the temperature is constant, this can be simplified as follows.

P(1)=Apf+B, f2+cpf'+Dp (5)
From equation (4), the coefficients A%e, c and D are each H1-)-H
7T+H9T2t..., H2+H8T+..., H3
+..., and Ho+H4T+H5T2+H6Ti5+
- Corresponds to. When performing a curve fitting technique, during one calibration step one selected signal is measured over a selected pressure range at a given operating temperature and the resulting values are used to calculate the coefficients of equation (5). is derived. During the measurement phase, pressure measurements are calculated from the frequencies of the selected signals by using the coefficients determined during a calibration phase in equation (6). When implementing the Lutsukatsuzotable technique, during one calibration step one selected signal is measured over a selected pressure range at a given operating temperature and the resulting values are recorded in Table C of Pressure vs. Frequency. ). During the measurement phase, pressure measurements are determined by examining Fi, a look-up table, and using interpolation techniques if necessary. Curve fitting techniques and look-up table and interpolation techniques are known.

Suitable curve fitting techniques & taken here for reference 1
Marcel Dakker, New York, 973
'Desc by lnc+Publishing%J, M0 Mendel
reteTechniques of Parsmst
er Estlmatlon 1gl! It is explained in Chapter 2. Appropriate interpolation techniques may also be used in the 1957 New York Me Graw-
Published by Hill Book Company Inc.

'Numerical Ana' by S. Kunz
lysts' fii+ Chapter 5 explains this.

The values of fa and fl) are monitored by processor 207 and compared with each other to detect deviations by more than a given tolerance. This deviation is indicative of non-uniform heat distribution in the diaphragm or failure of at least one oscillator.

Externally loaded diaphragms are shown in Figures 4 through 5. A cylindrical member 10, preferably of quartz, of length LO is cut into two sections 11 and 13 along cutting line 15 so as to maintain the continuity of the lattice across cutting line 15. Preferably, but not necessarily, the cut line 154-t optimizes the mechanical symmetry of the diaphragm. Each part of the cylindrical space 14 is formed by cutting sections 11 and 13, and by cutting i
Two longitudinal planes 128 and 12b are cut into the inner surface of the cylinder lO remote from f3!15, forming opposing parallel surfaces as already described for the embodiments of the internally loaded type. Planes 12a and 12bFi, thickness t
The depth is ``1'' to form each part of the diaphragm.
It is cut to The axis of the internal space 14 coincides with the axis of the cylinder 10.6 Various structural and The rollers are dimensioned as linear unless otherwise specified, but the type of material used, the type of SAW device W used for the base body, and the propagation of the surface sound wave energy that determines the position of the SAW device. The dimensions, which are a function of such things as orientation and pressure sensor specifications, can be optimized for a particular application.Cylinder 10 has a diameter ID of 26 mm and a length of IF L.
O# is 5Uro. Space 14 has a diameter of 10 lines π
and length #L, # is 55 gates. Each plane 12a and 12b#'i has a width of 5 mm and a length of 12 mm. The cutting depth rl is 6 ml.

The thickness tl-5vti- is determined based on the position of the hole 14 and the cutting depth "1" at which each plane is cut.

SAW devices may be formed on the flat surfaces 12a and 12b of the diaphragm, or directly on internal curved surfaces;
Alternatively, it may be formed based on other suitable configurations as described above. The diaphragm has an appropriate pressure resistance as described below.
t housing and connected to the electronic circuit shown in FIG. In this case, the SAW device 92028 corresponds to the plane 12a1 transmitter 168 and receiver 18a, and the SAW device! 202bti corresponds to 1i12b, transmitter 16b and receiver 18b. The operation of processor 2()7 is the same as described above.

The overall shape of the diaphragm is selected to withstand the selected high pressures with reduced physical mass. Although a cylindrical structure is superior to other shapes in these respects, the diaphragm of the present invention is not limited to a cylindrical shape.

Other shapes suitable as external and/or internal surfaces.

Examples include an oval shape and a labola shape.

Although the above description relates to cylindrical diaphragms, internally loaded spherical 4' diaphragms and externally loaded spherical 4' diaphragms are also included in the invention. An illustrative spherical diaphragm is shown in FIGS. 32 and 53. This older example has an external load. A spherical member 500, preferably of quartz, of diameter I[1ON] is cut into two sections 501 and 503 along a cutting line 505 so as to maintain the continuity of the lattice across the cutting line 5()5. Internal spherical space 5 with a diameter of 011
04 and each of the planes 502a and 502b form the section 50.
1 and 503 to form each part of the diaphragm having a thickness tl. Each SAW device 508a and 50
8b is formed in planes 502a and 502b.

Although the teachings of Book 8 regarding cylindrical diaphragms are generally applicable to spherical diaphragms, the primary stress experienced in a spherical diaphragm is a similar magnitude of orthogonal hoop stress. Thus, for example, the diameter Do
is 26TIA and DB is i[1liW. The planes 502a and 502b are cut to a depth rl of 2 mm, thus having a thickness t and a pitch of 5 U. Alternatively, the wall thicknesses may be made different by offsetting the center of the spherical inner surface and the center of the spherical outer surface, as described below for cylindrical diaphragms, or the wall thicknesses may be made of different thicknesses. May be cut.

Self-Temperature Compensation Figures 7-23 illustrate a self-temperature compensated embodiment of the pressure sensing diaphragm. The pressure response of such a pressure-sensing diaphragm is such that, although each frequency-temperature characteristic is the same, each frequency-pressure characteristic is a function of the different effective thicknesses of which the substrate of the diaphragm is made. is a function of the frequency of each of the two or more oscillators. Although all substrates are subjected to the same hydrostatic pressure, the pressure of the fluid causes each substrate to elastically deform to a different degree. As long as the diaphragm is comollantly (elastically) supported, temperature has an equal effect on the substrate. Therefore, the outputs of each oscillator are mixed and
Eliminate temperature effects. The elastic stiffness of self-temperature-compensated diaphragms is highly dependent on thickness, and therefore very small differences in substrate thickness are required.

In addition to providing temperature compensation, this technique also serves to advantageously offset the effects of long-term aging on pressure measurements, provided that the long-term aging characteristics of each of the constituent transducers are well matched.

An embodiment of a pressure sensitive diaphragm having the above characteristics and including two measurement channels is shown in FIGS. 7-9 and 12-13. Figures 7-9 show an internally loaded embodiment in which the cylindrical member 20 (preferably a quartz-like member) has four longitudinal planes 22a.

22b, 22c and 22d, these planes being milled into the outer part of the cylindrical member. Preferably, but not necessarily, these planes are distributed at 90 degree intervals from each other, measured perpendicular to the plane (as described below).

The planes on which the planes 22a and 22c are located are parallel to each other and perpendicular to the parallel planes passing through the planes 22b and 22d, respectively. Each plane 22a, 22b,
22c and 22d are milled to a depth of ``.'' A hole 24 having an axis indicated by an imaginary line bb is inserted into the cylindrical portion 1'20 having an axis indicated by an imaginary line aa. The axis bb is parallel to the axis 8a of the cylindrical member 20, but offset from the axis aa by a distance d (FIG. 7) in the direction of a suitable angle β (FIG. 9). , creating different thickness sections t1, t2, t3, t4 between each of the planes 22B-226 and the wall of the hole 24, m7 with internal # weights - FIG. The various structural parts in the embodiment may be dimensioned according to the teachings of FIGS. 1-3 and the accompanying description, except that holes 24
is the displacement angle β of about 56 degrees and the axis aahb of about 0.71
It is good to make it with the spacing of b. Milling depth rl is 2
A gate is fine. Milling depth “1” when milling each plane
and depending on the position of the hole 24, tl, t2, t3, t
4 is determined, and these thicknesses are each 5.4
關、6.4 Cabinet、6. 611! TI, 5.6 hearing.

For use in the self-temperature compensated embodiment, S[cut ((yxwl) 0°/42.75°, r=0°) and SST cut ((yxwl)0°/-49,22
An orientation around 10°, r=23°) has been found to be suitable, although many other single-rotated and double-rotated orientations are equally suitable for use. The ST cut is from Halland et al., US IF:j, No. 3.818, published June 18, 1974.
382 and is included here for reference. SST cut is 'Applied Phy
sics Letters' Volume 34, 817-81
B, published on page 9 (1979).

5lnha and H, F, Tier! 1ten's Ze
ro Temperature Coezu Flclent
of Delay For 5 surface Wav
es Inquartz' and is included here for reference. Also, the experimental proof is in the Procedures of the 1
980 UltrasonlcsSymooslum
(IEEE Cat, 800H1602-2) 17
T., Lukaszek and A., published on pages 5-183.

Ballato's 'What SAW Can Le'
arn from BAW: Imp cations
for Future Frequency Con
trol 5Selectlon and Slgna
tProcessing' and is included here for reference. ``For the nominal ST orientation at = 0, Δ1/1 is indistinguishably small near 25c, and l Δf I/f
op = 7 x 10-87 ps+.

"; For the nominal SST orientation at 23°, Δ1/1ΔT is uncomfortably small near 25C, and 1
Δt + /tΔp=1 7′/psi. Both orientations are satisfactory; both orientations yield zero first-order temperature coefficients of retardation for surface sound waves.

The weighting is applied to the ST orientation (with a conversion temperature of 40C) for the following reasons in the context of temperature compensation of
(yxwl) g°/40°, r = 0′) and SST orientation with a conversion temperature of 90°C (
(yxwl) mouth'/-49,2°, r=21.5°)
is selected. It can be seen that the degree of orientation specified above is an approximate cough. The actual degree of cut for the desired properties will depend on factors such as the electronics, the nature of the crystal material, the selected transition temperature, the interdigital transducer material and design, operation in overtone mode, etc. It can vary by ±4°.

The first plane 22a is milled in a plane ST perpendicular to a line displaced from the Y-axis by a rotation angle θ equal to −49.2° in the z-v plane. The second plane 22b is Z-
Equal to 40.0° in the Y plane, Ii-+1 rotation angle θ, □
It is milled in a plane perpendicular to a line displaced from the Y axis by −8. Since the crystal is diagonally symmetrical, the third plane 22 is a plane perpendicular to the section displaced from the Y-axis by a rotation angle of 130.8 degrees.
By milling c, the SST orientation can be reproduced on the side of the cylindrical member 20 opposite to the plane 22a, and the fourth By milling the plane 22d of the cylinder part side 20 opposite to the plane 22b.
The 5T-X cut can be reproduced on the side. The above orientation is desired for preferred operation of the self-temperature compensated embodiment, which is θ3, −8−θ5
It is displaced by s□=89.2°. Although each plane is preferably displaced from the other planes to optimize mechanical symmetry, i.e., each plane is displaced by 90° in this particular embodiment, this preferred relationship allows for 0. Small variations of 8u should not significantly degrade the nominal characteristics of the pressure sensitive diaphragm.

Techniques for suitably milling thousands of planes of preselected orientation are well known and will only be described here.

For example, if a suitable portion of a quartz cylindrical member, such as 20, is available for milling planes 228-22d to obtain the desired crystallographic orientation, the cylindrical member is Determined by whether or not it is formed correctly.

In order to obtain the fLfc orientation rotated once about Xl, the X of the crystal rough piece 50 shown in FIG.
After confirming the Y and Z axes, a cylinder 51 having a vertical axis parallel to the X axis is made from the crystal piece 50, preferably by a beering technique. Viewed in the direction of the X-axis perpendicular to the Y-2 plane (FIG. 18), the cylinder 51 is in the desired crystallographic orientation at a selected rotation angle θ with respect to the Y-axis in the y-z plane. Vζ is positioned to mill four planes with . The orientations of θ, 1-X and θ are shown in FIG.

Plane 228 soil transducer 26a s 28a
and transducer 26C128c on plane 22c.
is constructed according to the criteria that the propagation direction γ is equal to 21.5° and the power flow angle is equal to 0 degrees. Plane 22b
Upper transducer 26b.

28b and a transducer 26d on plane 22d,
28d is assembled according to the rule that the propagation direction r is conductively clean and the power flow angle is equal to zero degrees.

The operating frequency of the SAW oscillator is selected based on the available or preferred size of the associated SAW device, oscillator stability and Q. The suitable range of operating frequency is 150 Ml-1z -600 Ml-1z
In the embodiment described here, 200 MHz was selected. When a smaller substrate area is desired, the SAW device has a higher operating frequency, e.g.
It may be designed to have an operating frequency of Hz. However, such devices must be designed and constructed with extreme care to avoid parasitic effects that would cause performance degradation.

A self-temperature compensating internally loaded pressure sensing diaphragm is shown in FIGS. 10 and 11. It is mounted within the pressure housing shown, which makes the diaphragm compliant.
pHantly) must be supported (elastically). The pressure housing comprises cylindrical stainless steel casing members 71, 72, 73 which engage each other along appropriate joints and are threaded 302.3.
04.306.308 and other means (not shown) as necessary to keep it tightly sealed. A fluid-tight contact between the housing members 71.73 and 7], 72 is ensured by seals 301.303, which may be made of a suitable material. End casing members 7j, 72
#-J are each provided with an introduction lower 8.79 for introducing fluid into the chamber 69 and into the diaphragm. cylinder 20,
The solid body consisting of the end caps 62, 64 and the cylinder 66 is 85 nI#I and is supported within the pressure 11 housing by a number of elastic members 309-320 to form a chamber 69 into which fluid is introduced. The resilient members 309-320 may be, for example, loosely fitted nylon rings. Chamber 69 communicates with hole 24 through chambers 75,77. To reduce shear stress across the joint between the end caps 62, 64 and the cylinder 20, the large diameter portion of the chamber should extend approximately 17 mm into the end caps. The end gaps 62,64 are defined by the inner edge of each continuous circular flange and the outer edge of each end of the cylinder 20.
111 is tightly engaged. The end caps 62, 64 also snugly engage the inner end of the casing 66 at the outer edges of their respective flanges. The end caps 62, 64 are manufactured using the well-known glass frit method (g'1ass
It is sealed to the cylinders 20 and 66 at the contact area using a suitable technique such as a frltteehnlque). If the crystallographic orientations of the diaphragm, end caps 62, 64, and cylinder 66 are well matched to produce a continuous crystal lattice, the above arrangement provides a compliant support for the diaphragm. is created. Preferably, the glass frit binder should have a coefficient of thermal expansion similar to that of the crystals and should be applied as a layer as thin as possible.

a generally cylindrical chamber 68 bounded on the outside by the cylinder 66, on the inside by the cylinder 20, and at each end by the annular inner surface of the end cap 62,64;
is formed - J tL. Sledding.

planes 22as 22b, 22c, 22d and their respective transducer pairs 26as 28a %2(i
b, 28b, 26c, 28c, 26d,
Chamber 68 is evacuated to create a favorable environment for the correct operation of the four delay lines 28d. Each transducer 26a-d and 23
a-d are respective thin insulated wires 74a-74
1 by d and 76a-76d. Each terminal 70a-70dK is connected to the outside of the steel casing member 73 and insulated therefrom. The wire may be any suitable thin wire such as Teflon coated aluminum alloy, cylindrical 66, elastic front 311.319.
319, 320 and through respective narrow grooves provided in the housing fib material 73. These grooves are suitably sealed to maintain a favorable environment within chamber 68 and the Ire body within chamber 69. Pressure-measured fluid is introduced into a pressure introduction lower 8.79 made in the end cap 62.64 in direct alignment with the bore 24.

When a fluid is introduced into the hole 24, the 11 (IMj 2 g) deflects according to the pressure of the introduced fluid and adjusts according to the temperature of the introduced fluid. The pressure sensor is small and all its elements, / , cylinder 20, end lNl1 cap 62
．． 64, the cylinder 66 quickly reaches a state of thermal equilibrium. However, due to the difference in thickness between the planes 22F1% 22bt 22C% 22d and the hole 24, the planes 22a, 22b
, 22c, and 22d, the degree of deflection of each area of the circle m20 is different.

The first example is a self-temperature compensation type in which a cart is hung outside.
2 and 16. A cylindrical member 30, preferably of crystal length LQ, is sliced along cuts 35 into two sections 3], 33. Preferably, the cuts are made parallel to the 35 x-1 plane (along the line of the Y-axis in Figure 18).The coefficient of thermal expansion along all directions in this plane is the same (1!1.71 x 10- 6/
C), in order to reduce the stress generated along the cut 35, a glass frit bonding material with a coefficient of thermal expansion equal to or similar to that of the crystal '6 material in the X-1 plane is used. It is better to choose. The cut in the x-1 plane uses the 5T-X and SST orientations,
Gives good but not exact mechanical symmetry. By milling the sections 3], 33, respective sections of the cylindrical space 34 are created, leaving the cut 35 with four longitudinal planes 32 inside the cylinder 30.
a532b, 32c, and 32d are formed by milling to create an opposing SST orientation in the same manner as described above for the internally loaded type embodiment.Inner space 3
One axis of 4 coincides with the axis of cylinder 30. By milling the opposing planar sections to a depth of 4, regions of diaphragm with different thicknesses are created. Accordingly, planes 32a132c are milled to depths rl and ``2'', respectively, resulting in different thicknesses t.
l and t2, and planes 32b, 32d have depths rl and r2, respectively.
are milled to form diaphragms 1fl1 with different thicknesses tl and t2, respectively. If desired, each of the planes 32a-32d may be trap milled to different depths. Transmitter-receiver pair 368138 a and 36bJ asb and 36c, 38
A SAW delay line consisting of c, 36d, and 38d is created in each plane 328-32d. Once the SAW device is fabricated, the two parts 3J, 33 of the cylinder 300 are joined together, preferably by glass frit joining method. Respective planes 32a-326 and transducer pairs 368.38a and 36b, 38b and 36c y 38
In order to form a good environment for the four delay lines including c and 36d138d to work properly, chamber 34
is exhausted. Leads from the SAW device are made on the surface surrounding chamber 34 and run through the bonding layer to terminals on the outside of the pressure sensing diaphragm.

Details of the completed diaphragm housed within a suitable pressure housing are provided below.

In the externally charged type embodiment of FIGS. 12-13, the critical structural parts may be dimensioned according to the teachings given in FIGS. 4-5 and the accompanying description. , the milling depth ``1'' shall be 2++ m, and the milling depth ``2'' shall be 4 m.

The position of the space 34 and the milling depth "1" and r2 for milling the plane determine the thicknesses t1 and t2.

These thicknesses are 6 layers and 4 layers, respectively.

A self-temperature-compensating, internally-charged pressure-sensing diaphragm is mounted within the pressure housing.
4 and 15.

The pressure housing consists of a cylindrical stainless steel casing 40.4J, 42 which engages one another along appropriate joints such as a "rabbet" JJ joint and is threaded 330 .3
31, 332, 333 and the culm as necessary by means of its flu. For example, Fj: a seal 56 made of any suitable material, such as polyminide.
．． 571C, housing members 40.41 and 4
A fluid-tight contact between 0.42 and 0.42 mm is ensured.
The housing members 41,42 each have an inlet 58,59 for introducing fluid into the chamber 45 and directing the fluid to the diaphragm. The cylinder 30 has a large number of elastic parts 43a-43c, 47a-47c,
340-343 and into which fluid is introduced)1. A chamber 45 is formed. Respective leads from transducers 36a-36d and 38a-38d are made on the surface surrounding chamber 34 and pass through the bonding layer, the resilient member 478, the small v-groove' in the housing member 41, and into the Terminal strip 48 is reached, suitably mounted on top. The grooves are properly sealed. Only the lead wire 44d connecting the transmitter 36d'i groove 48 and the lead wire 46d connecting the receiver 38d to the terminal 49 are shown, and other lead wires are omitted to simplify the diagram. .

When fluid is introduced into the annular chamber 45, the cylinder 30 deflects according to the pressure of the introduced fluid and adjusts to the temperature of the introduced fluid. The pressure sensor is relatively compact and all its elements quickly reach thermal equilibrium. However, plane 32
Because the thickness of the substrate corresponding to a % 32c and plane 32b132d is different, each portion of cylinder 30 in these areas deforms to a different extent.

Both internally loaded and externally loaded versions of the self-compensating pressure sensing diaphragm provide two independent temperature compensated pressure measurements. A typical circuit that can be coupled to the pressure sensor of either FIG. 10 or FIG. 14 to obtain improved results is shown in FIG. Two measurement channels are shown in FIG. 16, one of which is the excavator 8.
8a, 88c, mixer 90, counter 91.92.
Including 93, others are excavators 88b and Rad.

Includes mixer 94, counter 95,96,97. For example, SAW devices 82a, 82b include transmitters 26a-26d and receivers 28a-28de mounted on planes 22a-22d, respectively.

82c and 82d are provided on the diaphragm 80. The crystallographic meliorientations of devices 82a, 82C are the same (near the SST orientation), but their respective substrate thicknesses are different, so when subjected to the same temperature and hydrostatic pressure, devices 82B, 82C have the same frequency-l altitude. A SAW device 82 with different frequency-pressure characteristics
a, the output (fa) of the oscillator 88a including the amplifier 84a and matching circuits 11385a and 86a, and the output (fc) of the oscillator 88c including the SAWm device 8 C1 amplifier 84c and the matching circuit 85e. Sent to mixer 90. The output of the mixer 90, the difference f6-f0%, is sent to the counter 92, which counts the frequency of the input signal and outputs its digital display, thereby converting the analog output of the mixer 90 into a digital signal. Convert to Counters 91 and 93 count the surface wave numbers of fc and fa, respectively, and provide a digital display thereof. Similarly, the crystallographic melientations of devices 82b and 82d are the same (near the ST-X orientation).
, and their respective thicknesses are different, so that devices 82b, 82d have the same frequency-temperature characteristics and different frequency-pressure characteristics when subjected to the same temperature and hydrostatic pressure. S.A.
W tube 82b, additional +JJ device 84b1 matching circuit network 85b,
The output (fb) of the oscillator F18b including 86b and S
AW device 82d, amplifier 11] device 84d, matching circuit network 85d
, 86d is sent to the mixer 94. Output of mixer 94, difference fb-
fd, is sent to the counter 96, which currents the frequency of the input (No. 1) and outputs its digital representation, thereby converting the analog output of the mixer 94 into a digital signal. and fb frequencies and provides a digital display thereof.

Although not shown in FIG. 10 or 14, the excavator 88
The a-88d may be fabricated as integrated circuits, which are designed to shorten the lead wires to reduce deformation effects and improve excavator stability without affecting the elastic deformation of the diaphragm. Mounted on a surface within the exhaust space 68.34, sufficiently close to the associated SAW equipment.

fa, fc and fa-fc, and fb, fd and fb-
A digital signal representing fd is provided to a processor 98 which determines a measure of pressure and provides the result to a recorder 99. signal fa.

fb, f(,, fd are weighted types (welg
htlngtype) is used for C crystallinity compensation, and is not required for self-one-quality compensation. If only self-temperature compensation is desired, the counters 91, 93, 95, 97 providing D temperature compensation may be omitted from the circuit of FIG. Reset counters 91-93 and 95-97.

Processor 98 executes a curve fitting routine to determine the pressure measure of it from fa-fc and fb-fd.
) or a lookatznotesol and interpolation means. These means are provided essentially as described in connection with FIG. However, in place of the parameter IrfN in equation (5), f, -fc or fb-fd
can be entered.

The present invention also contemplates other self-once compensated embodiments. For example, an embodiment is shown in FIGS. 19-20 in which tWj It is applied externally based on the features of an eccentric hole and an angle measurement. A circular member 13° of length LQ, preferably made of quartz material, is sliced along cuts 135 into two sections 131 and 133. Preferably.

135Fi, ST ori 1 facing opposite as above
4 milled into the interior of the cylinder 130 to create an alignment and an opposing SST orientation.
two longitudinal planes 132a, 132b,] 32c,]
32d must be made in the x-7 plane to provide as much mechanical ablation as possible without disturbing 32d. Each plane 1: (2a, ]32b, 132c, 13
2d is milled to a depth of 1. A space 134 of length Ll with an axis shown by imaginary line bb is formed at a position equidistant from the end of cylinder 13 ( ) with an axis shown by imaginary line aa. 130.The axis bb is parallel to the axis a8 of the cylinder, but it is offset by an appropriate angle β, and this η
- Displaced by a distance d from
, t2, t3, and t4 are created.

The various structural parts in the externally sprung embodiment of FIGS. 19-20 are dimensioned according to the teachings of FIGS. 4-5 and the accompanying description, except that the space 134
is created in the cylinder 130 with a displacement angle β of about 51 degrees and a displacement d of about 1.5 degrees between axes aa and axes bb. Depending on the location of the hole 134 and the milling depth rl that creates each plane, the thickness 1, 12. 1. , t4 are determined, which are 4.91+1., respectively. 6.9IJ, 7.1iL
ff, 5.11ff.

The orientation of the milled plane is selected on the same basis as above, and the fabrication of a suitable SAW device is carried out in the same manner as above. Once the SAW capping device is closed, the two parts 131, 133 of the two cylinders 130 are joined and placed in the housing described with respect to FIG. 14 and FIG. 15, and the diaphragm is coupled to the measurement circuit of FIG. 16.

In other embodiments of internally loaded sensing devices, the axes of the hole and cylinder are coincident, but the planes are milled to different depths to form different substrate thicknesses in accordance with the present invention. For example, in Figure 21, the opposing plane 150
a, 150c have a defined orientation, e.g. SST orientation, which are milled to different thicknesses r+flp and r2, respectively;
A configuration is shown creating portions of the diaphragm with different thicknesses tl and t2, respectively. Similarly, the opposing planes 150b and 150d each have a thickness r,
and r2, respectively, to a boundary thickness t
Create a diaphragm section with l and t2. Plane 1
The milling depth of 50a% 150b is the same ("I") and the milling depth of plane 150c% 150d is the same ("I").
2) However, each plane may be milled to a different depth if desired.

A simplified embodiment of a self-temperature-compensating pressure-sensing diaphragm lacking multiple measurements is shown in FIG.

Following the same teachings shown as an internally loaded device, an externally loaded device can also be constructed. The embodiment shown in FIG.

Plane 1 milled to depth “1” and “2” respectively
Only one measurement channel including 608.160b and!
16 requires associated electronic circuitry such as that contained in one of the channels in FIG.

Said orientation is an orientation rotated once about a diagonal axis. Other suitable orientations may also be advantageous in some applications, for example an orientation rotated once or twice around a trigonal axis. The diaphragm is shown in FIG. 22 with an orientation rotated once about a three-sided axis. Second
Figure 3 shows a single measurement channel containing a linked plane 1708.170b% 170c, respectively, at depth 'I''2, r3 K. The third plane in the measurement channel is Gives an extra reading to improve the level of reliability.

It has been found that the directions near the temperature-compensated ST and SST directions of the weighting type have different characteristics. This is conveniently used in the present invention.
Temperature compensated pressure measurements can be made or even the response time and accuracy of the temperature compensated pressure measurements can be improved. In particular, these directions indicate the 'transition' temperature. The frequency-temperature characteristic of the SAW device exhibits a parasitic behavior, which means that the temperature dependence of the frequency around the transformation (reference) temperature is minimal. Therefore, temperature-induced errors in measuring pressure will be most pronounced at temperatures furthest from the tipping point, where the fluid being measured is subject to temperature fluctuations ranging, for example, from 0°C to 150°C. 40°C and 9°C to give high accuracy.
Two separate pressure measurements obtained with the SAW device with each conversion temperature of 0° C. are combined to form a more consistent and accurate measurement as detailed below.

Two suitable directions yield a conversion temperature of 40°C (
yxwl ) 0' /40, 0°, r==[10
and yielding a conversion temperature of 90°C (yxwl)
0'/-49.2°, r=21.5°. The values of Δ1/fΔT and Δf/fΔP in each direction at these conversion temperatures are the same as described above.

The conversion temperature of a SAW device can be varied over a wide temperature range by slightly changing the direction of propagation, or both, by one angular percent of rotation. For example, for the direction near the ST cut, with the propagation direction held constant along the trigonal axis, the conversion temperature increases with decreasing rotation angle, and for the direction near the SST cut, the conversion temperature increases with decreasing rotation angle or decreasing propagation direction, the other being held constant.

Weighted type temperature compensation supplements self-temperature compensation in applications requiring highly accurate pressure measurements. For such purpose of use.

Even if ta and fC or fb and fd are mixed, the influence of temperature will not be removed to an acceptable level. Rather, self-temperature compensation techniques can be considered to provide accurate and stable operation over a very wide but limited temperature range under these conditions.

FIG. 24 is a graph illustrating the wide range in which undesired temperature-induced effects are substantially reduced by self-temperature compensation techniques. FIG. 24 is for illustration purposes only, and for the sake of clarity, the 10° deviation shown for the conversion temperatures of two SAW devices with similar directions for each channel is actually It will be understood that this is greater than what would occur. Song 1j, 402a
and 402b is (yxwl) 0°/40.0°,
The curve 404 represents the frequency-temperature characteristics of two SAW devices with ST force direction of r=00, while the curve 404 represents the frequency-temperature characteristic of the self-temperature compensation channel based on the SAW device with ST force direction. It represents. Away from the selected conversion temperature of 40°C, curves 402a and 4
02b changes rapidly, and curve 4 immediately near the conversion temperature
In all areas except 02a and 402b, SAW
This shows that the response of the device is greatly affected by temperature. Curve 404 varies very sharply near the conversion temperature in the range 0°C to 30°C, indicating that the response of the self-temperature compensated channel is only slightly affected by temperature within this range. ing. Curves 406a and 406b are (yxwl) O'/
-49,2°%r=21.5° SST direction also :)
2-1) respectively represent the frequency-temperature characteristics of the SAW device, while a curve 408 represents the frequency-temperature characteristic of the self-temperature compensation channel with the SAW device as the pace with the SST direction. Above the selected conversion temperature 906, curves 406a and 406b change rapidly, and the response of the SAW charger becomes significantly influenced by temperature in all regions except the portions of curves 406a and 406b immediately near the conversion temperature. It shows that it is received by the width. Curve 408 is [1U-1
It only changes very slowly around the conversion temperature in this range of 30°C, indicating that the response of the self-temperature compensated channel is only slightly influenced by temperature within this range.

The effect of temperature on the #S7 TJ and "SST" channels is generally negligible, but at about 40°C, as shown by curve 404, there is no effect of temperature on the #37 # channel, and the curve At about 90°C, as shown by 408, I S S
There is no temperature effect on the T It channel. This feature is effectively utilized in weighted type temperature compensation.

In weighted temperature compensation, each channel response is weighted based on its frequency-temperature characteristic.

A simple weighting function is shown in the graph of FIG. It represents
Curve 414 shows the weighting applied to the pressure measurements measured in the 'SST' channel and the temperature measurements measured in the 'SST' channel. The converted temperature measurements are provided as output to a recorder 99 (FIG. 16).

The weighting function shown in FIG. 25 is based on frequency-temperature characteristics in the 3T and SST directions over a wide temperature range. SAW as a function of frequency and pressure
The temperature response of the device is a typical two-dimensional polynomial, T(f, P)=I. (6) 3 +I, i + I, f + I, f + ---+technique 4
p + z, p2 + engineering p5 + +++++ X fP
+ I8zu2ρ ten 1. fP2 + --- The pressure response of the SAW device as a function of frequency and temperature is given by Equation (4)
This is expressed as follows.

P (zu, T)==H.

+ H, f + H2f2+ H3f3-1----+
H4T + H5T + H6T3+ ---+ H
, fT + H8f T + H7fT + --- Weighted type temperature compensation techniques are used in conjunction with curve fitting techniques. Each of the four oscillations F) 88a to 88d has one formula (
4) and configured to provide pressure measurements as a function of wave number and temperature, and temperature measurements as a function of frequency and pressure, according to the two-dimensional polynomials for pressure and temperature measurements given in (6). be done. During calibration, counter 9
3.97% 91°95. Signal from 92 and 96 a
, zb% fc.

fd, fs -fc and fb -fd are measured over a selected wide range of pressures and temperatures, and the coefficients of the polynomials are determined using the Nocellameter Estimation Technique 1, e.g. is determined using a least square parameter estimation technique.

During the measurement process, an approximate pressure measurement 1 is obtained from signals fa-fc and fb-fd, which are the outputs of mixers 90 and 94.
You can get direct results. These approximate pressure measurements--approximate because they are slightly affected by temperature--are averaged, and the results are used to calculate equations (6) for fa, fb, and fb, respectively.
By applying fc and fdK respectively, four SAWs
Approximate temperature of the device can be determined. The average temperature is determined and is considered to be the best temperature estimate for the following iterative procedure.

Determination of each temperature from the SAW device is performed using one set α1 and fi
The weighting given by ll and shown in FIG. 25 is weighted as a function of the best temperature estimate according to a function to obtain an improved best temperature estimate. Using this improved best temperature estimate in equation (4), the signals fa−fc and f
Improved pressure measurements are obtained from b-fd. The resulting improved pressure measurements from the two channels are given by equations (7) and (8)
The weighting shown in the figure is weighted as a function of the best estimate temperature according to a function, resulting in an improved best estimate pressure.

If the results for the best-estimated temperature and the best-estimated pressure converge appropriately #i, the best-estimated value is considered the correct temperature and pressure measurement. Otherwise, using the improved best estimate pressure in equation (6).

fa% fbafc and fd□, which are processed as described above, to obtain their respective temperature measurements.

The curves 4]2 and 414 that determine the best estimated pressure are expressed by the following equations.

Town □ (7) Town + W2 However, the quantity w1 and town are the formulas Rho90'+3 and IT-, respectively.
40613, where p and ■ are 0℃≦T≦1
The temperature is 60°C. The best estimated pressure is given by the equation:

The curves 414 and 412 that determine the best temperature estimate are expressed by the following equations.

1 Yl +Y2 However, the quantities y1 and Y2 are the formulas Rho 40°13 and I, respectively.
It is expressed as T-9Ql, and C1T is 0℃≦T≦
The temperature is 160°C. The best temperature estimate is given by:

Although the weighting technique was explained as an optimization technique in the example of self-temperature compensation, it is also applicable to the example without compensation (e.g.
Other embodiments (for example, the embodiments shown in FIGS. 19-20 and 21) including the embodiments shown in FIGS. 1-6 and 4-5 are also applicable. For example, when applied to the embodiments shown in FIGS. 1-5 and 4-5,
The narrow nominal temperature range for the calibration temperature, which is performed accurately in the embodiments of FIGS. 6 and 4-5, can be widened. For example, if the weighting technique is used in the embodiment shown in Figures 1 and 3, planes 2a and 2b will be #B.
7N direction, while two other planes are provided as described above, having the same thickness as these planes 28 and 2b but with a direction in the #S5711 direction. The curves 404 and 408 are much larger than the curve 4028% in Figure 24.
The weighting function can be modified appropriately to represent the temperature-frequency characteristics of 402b and 406a, 406b.

Correction of Measured Values Figures 26 to 61 show embodiments of pressure sensitive diaphragms that measure pressure and temperature separately. The measurement-corrected pressure-sensitive diaphragm according to the invention comprises at least two
There are two SAW devices, one primarily pressure responsive and the other primarily temperature responsive. The SAW devices are connected to respective amplifiers and matching networks to form respective oscillators.

The output of the oscillator is fed to a suitable processor which compensates the pressure measurements according to the temperature measurements. The output of the processor is sent to a suitable indicator or recording device. In the internally loaded embodiment shown in FIGS. 26 and 27, one cylinder 230 has four planes 232a.
~232 d is cut. Planes 232a and 232c
whose direction is the SST direction and the plane 232. The directions of b and 232d are 37 directions, and they are arranged on the cylinder 230 as described above. ycs+ for cylinder 230
as is provided, the axis of which hole 238 coincides with the axis of cylinder 230. The thickness between the wall of the hole and each plane 2328-232d is t.

Although it is preferable that each plane be cut to a uniform depth r+K, this need not necessarily be the case. Four interdigital transducers are attached to each plane. For example, a preferred placement of plane 232B is shown in detail in FIG. Interdigital transmitter 234a and receiver 235a form a delay line such that one surface acoustic wave energy propagates along the dd line.

Interdigital transmitter 236a and receiver 237
a forms a second delay line such that one surface acoustic wave energy propagates along the c-C line. The various structural components of the diaphragm of FIGS. 26 and 27 are dimensioned as described with respect to FIGS. 1-5. The external loads shown in FIGS. 29 and 30 are In one embodiment, a cylinder 240 of length Lo, preferably of quartz, is cut into two sections 241 and 2 along a cutting line 248.
It is cut into 43 pieces. Preferably, the orientation of cutting line 248 is selected parallel to the X-Y plane and the appropriate bonding material is selected as described above, but this need not necessarily be the case. A portion of the generally cylindrical inner surface 249 is formed in sections 241 and 243 such that when assembled, they form a closed coaxial cylindrical space on their inner surfaces.

Four planes 2428 to 242d are cut into the cylindrical inner surface 249. Opposed planes 242a and 242C are oriented in the SST direction and opposed planes 242b and 242d are oriented in the ST force direction and are disposed in cylinder 240 as described above. Each plane has a thickness of 1 between the outer surface of the cylinder 240 and each plane 2428 to 242d.
．． 04 interdigital transducers cut to a uniform depth "2" are preferably deposited on each plane as shown in FIG. 28. For example, interdigital transmitter 244a and receiver 24
5a forms a delay line such that the surface acoustic wave energy propagates along the dd line.

Interdigital transmitter 246a and receiver 247a
forms a second delay line such that the surface acoustic wave energy propagates along the C-CM. The various structural features of the diaphragm of FIGS. 29 and 50 are dimensioned as described with respect to FIGS. 4 and 5.

An important consideration in designing the SAW delay line shown in Figure 28 is to reduce crosstalk between adjacent interdigital transducers, which can be caused by e.g. The interdigital transducers may be electrically shielded from each other by metallizing opposite surfaces, or by providing sufficient spatial separation to electrically isolate the interdigital transducers from each other.

can be brought down to an acceptable level. Although the propagation paths that intersect are optimal so that the pressure and temperature directions are the same, the present invention also contemplates the use of propagation paths that do not intersect with each other.

Such a configuration provides good electrical isolation for multiple interdigital transducers placed on the same plane.

The pressure sensitive diaphragm shown in FIGS. 26-27 and 29-50 is mounted within a suitable pressure housing as detailed above and as shown in FIG. connected to appropriate electronic circuitry.

For example, Figures 26 to 27 or 28 to 3
Diaphragm 270 representing the diaphragm of Figure 0
Ku, e.g. planes 232 a to 232 d or plane 2
Four planes 2728~ representing 42a~242d
272d is provided. Each plane has a pressure direction and a temperature direction. It has been found that SST and 37 rotations can provide temperature direction and pressure direction if the appropriate propagation direction is chosen. (yxwl)
If an SST direction of O'/-49, 2° is chosen, r==Q6 is typically Δf/fΔd=19
gives a temperature sensing direction denoted by
= 10/ps'l and Δf/fΔT gives a pressure sensitive direction such that it is small and approximately 90°C. (yxwl
) If the 3T direction of 0°/40° is chosen, r=55° is typically Δf/fΔT=20X10/
gives the temperature sensing direction denoted by l, while “~00 is typically lΔfl/fΔP=7X10/psl and Δ
f/fΔT gives a pressure sensitive direction such that it is small and about 40°C. Suitable temperatures and pressure directions for the embodiments of Figures 26 to 27 and 29 to 30 are shown in the table below. The circuit of Figure 31 has four independent measurement channels 274.
a-274d, with channel 274a shown in representative detail. A temperature sensitive oscillator consisting of matching network 280, 281 and amplifier 282 produces an output that is digitized by counter 283 and sent to processor 298 as signal 'at. A pressure sensitive oscillator consisting of matching network 284, 285 and amplifier 286 produces an output which is digitized by counter 287 and provided as signal I to processor 298p. Similarly, channel 274b.

274C and 274d are respective signals f. and fbp.

'at and fcp, and fdt and f d p to processor 298.

Processor 298 executes either a one-curve fitting routine or a look-up table interpolation routine to determine the temperature-corrected pressure.

In either case, as an internal operating phase, the signal f at the selected pressure over the required operating temperature range
Both t and d are measured. These values are then used to derive the coefficients of the selected curve fitting equation or to determine the individual entries of the look-up table at each selected temperature.

In performing the curve fitting technique, the oscillators in each plane are calibrated to provide a pressure measurement as a function of frequency and temperature, and a temperature measurement as a function of frequency and pressure, respectively. Typical two-dimensional calibration polynomials for temperature and pressure measurements take the form of equations (4) and (6). Plane 2
The two oscillators combined at 72a are square 272b,
272c and 272d are representative of the combined oscillator pair.

During calibration, the operating frequencies of two oscillators on plane 2728, producing signals 'at and f a p, respectively, are measured over a wide range of selected pressures and temperatures.

Then, the polynomial T(4゜P
) and the polynomial P(
The coefficients of f, T) can be calculated using A' parameter estimation techniques, e.g.
It is determined using the nine least squares/'P parameter estimation technique described in Mendel et al. During the measurement phase,
An approximate temperature measurement is obtained from fat using the following approximation derived from equation (6).

■(fl = ATf + 8.f2 + CTf!'
+ DT a3 Use this approximate temperature value with the formula +41 K to determine the best estimate of pressure. This technique is iterated by using this best estimate of pressure with tat in equation (6) and the resulting best estimate of temperature with fap in equation (4) until the results for pressure and temperature converge properly. Applies to tl.

When implementing a look-up table technique, during the calibration phase the signal is measured over a range of selected pressures and temperatures and the resulting value is determined as the pressure fa.
It is stored in a three-dimensional table of t and fap. During the measurement phase, check the Fi, look-up table and, if necessary, appropriate interpolation techniques for the three variables...
By using K as explained in the literature of Mr. Unz, which is taken here as a reference,
A pressure measurement is determined.

Although the measurement correction compensation technique has been described herein for a single plane, the technique can also be applied when the oscillators on each plane or other region of the diaphragm each have a temperature direction and a pressure direction. for example.

When applied to the embodiments of FIGS. 1 to 3 and 4 to 5, the planes 2a and 2b have an "ST" direction with "=0°" so that the planes 2a and 2b are sensitive to pressure, while the plane Two further planes of the same thickness as 2a and 2b but with the #S S7 # direction at r=0° so as to be temperature sensitive are provided as described above.

Although the invention has been described above with reference to specific embodiments, these embodiments are merely illustrative and the invention is not limited to these embodiments. It will be apparent to those skilled in the art that various modifications may be made within the spirit and scope of the invention. For example, temperature-induced frequency shifts for a SAW pupil formed on a diaphragm housed within a compliant structure are essentially driven by crystallographic orientation, whereas pressure-induced frequency shifts are Details of the diaphragm structure, geometric shape, engineering
Much depends on other factors such as the design of the end cap, how it is loaded, and the direction chosen. Accordingly, variations in these and other elements are intended to be included within the scope of the invention.

[Brief explanation of drawings]

Figure 1 is a perspective view of a pressure-sensitive diaphragm with a load applied inside. 2 and 5 are a sectional view taken along the axis of the pressure-sensitive diaphragm of FIG. 1 and a sectional view taken along a plane perpendicular to the axis of the pressure-sensitive diaphragm of FIG. 1, respectively. 4 and 5 are cross-sectional views of a pressure-sensitive diaphragm with an external load, respectively, taken along the axis of the diaphragm and in a plane perpendicular to the axis of the diaphragm. FIG. 6 is a schematic diagram of an electrical circuit suitable for obtaining pressure measurements from the pressure sensitive diaphragms shown in FIGS. 1-3 and 4-5; FIG. Figure 7 is a perspective view of a self-temperature-compensating pressure-sensitive diaphragm with a load applied inside it, and Figures 8 and 9 are cross-sectional views taken along the axis of the pressure-sensitive diaphragm in Figure 7, respectively. A sectional view taken in a plane perpendicular to the axis of the pressure-sensitive diaphragm. 10 and 11 are cross-sectional views of the housing and the pressure-sensitive diaphragm of FIG. 7 installed therein, respectively, a cross-sectional view along the axis of the diaphragm and a plane perpendicular to the diaphragm axis. Cross-sectional view. 12 and 16 are cross-sectional views of an externally loaded self-temperature-compensating pressure-sensitive diaphragm, respectively taken along the axis of the diaphragm and in a plane perpendicular to the axis of the diaphragm. 14 and 15 are cross-sectional views of the pressure-sensitive diaphragm of FIGS. 12 and 16 installed in the housing and the diaphragm, respectively; 16 is a cross-sectional view taken in a plane perpendicular to the axis of the diaphragm; FIG. 16 is an electrical circuit suitable for obtaining pressure measurements from the pressure-sensitive diaphragms shown in FIGS. Schematic diagram. FIG. 17 is a perspective view of a raw crystal stone, showing the hollowing out of a crystal column in a given direction. Figure 18 is a schematic diagram showing the position of the plane of the selected crystallographic direction in the crystal cylinder of Figure 17, Figure 19 and Figure 2.
Figure 0 is a cross-sectional view of another embodiment of a self-temperature-compensating pressure-sensitive diaphragm with an external load, respectively taken along the axis of the diaphragm and in a plane perpendicular to the axis of the diaphragm. figure. Figures 21, 22 and 25 are cross-sectional views of various further embodiments of internally loaded self-temperature compensating pressure sensitive diaphragms along a plane perpendicular to the axis of the diaphragm. A cross-sectional view. Figure 24 shows the weighting f/f△■ as a function of temperature in the 5T-X and SST directions for a non-temperature compensated structure and a self-temperature compensated structure to illustrate the temperature compensation in the equation. Figure 25 is a graph showing one weighted function used for temperature compensation in the weighted equation. Figures 26 and 27 are graphs showing a pressure-sensitive diaphragm for measurement compensation type temperature compensation with internal load. 28 is a sectional view taken along the axis of the Be earphragm and a sectional view taken in a plane perpendicular to the axis of the Be earphragm; FIG. 28 is a sectional view taken from FIGS. FIG. 3 is an enlarged view of a plane representative of the planes provided in the illustrated embodiment; FIGS. 29 and 60 are cross-sectional views of a pressure-sensitive diaphragm for measurement-compensated temperature compensation with an external load, each l
゛A cross-sectional view along the iaphragm axis and a cross-sectional view taken in a plane perpendicular to the axis of the iaphragm. Figure 51 is a schematic diagram of an electrical circuit suitable for obtaining pressure measurements from the pressure sensitive diaphragms shown in Figures 26-27 and 29-50. FIG. 52 is a perspective view of a spherical pressure-sensitive diaphragm with an external load applied thereto, and FIG. 63 is a sectional view taken along the pressure-sensitive diaphragm diameter direction of FIG. 62. 1... Cylindrical member, 2a, 2b... Plane, 4... Hole, fia, 6b, 8a, f3b --- Tiger 7 thread Yusa. 10...Cylindrical member% 11.12...Classification, 12a
. 12b...Plane% 14...Cylindrical space, 15.
... Cutting line 516a*16b ... Transmitter, 18a, 1
8b--Receiver, 200...Diaphragm* 20
2a+202b ・S A W device, 203a, 2
03b-Oscillator, 208a, 208b--Counter, 204a*204b--Broadband amplifier, 206a, 206b. 213a, 213b... matching circuit network, 207...
Processor, 209...Recorder. Engraving of drawings (no change in content) FIG, 2 JP-A-138431 (FIG of g, 25 F21 to FIG, 26 FIG, 27 Procedural amendment (method) Mr. Kazuo Wakasugi, Director General of Japan Patent Office 3. Relationship between the person making the amendment and the case Applicant 4, agent 6, subject of amendment All drawings - dark, -1

Claims (1)

Claims: (1) In a surface acoustic wave signal frequency device with a crystalline diaphragm section. a cylindrical or spherical outer surface and a cylindrical or spherical inner surface, one of the outer and inner surfaces being adapted to receive an applied pressure, and the other of the outer and inner surfaces having a selected orientation of and a second region having substantially the same orientation as the first region and used to form the surface acoustic wave device; said first surface and said first surface adapted to receive a pressure applied thereto;
A first portion of the diaphragm section between the region has a first predetermined thickness and is adapted to be subjected to an applied pressure.
A second portion of the diaphragm section between the regions has a second predetermined thickness different from the first predetermined thickness. 2. The device of claim 1, wherein said diaphragm section has a continuous crystal lattice structure. (3) The directions of the first and second regions are the ST force direction and the S
Claim No. 1 selected from the group consisting of ST direction (
(4) The other surface is further oriented in a selected direction that is different from the directions of the first and second regions. a third region used to form the acoustic wave device; and a fourth region oriented substantially in the same direction as the sixth region and used to form the surface acoustic wave device, a fifth portion of the diaphragm section having a third predetermined thickness and having a thickness of 1tCtb between the surface adapted to receive and the third region; The fourth portion of the diamond slam section between the four regions has a fourth predetermined thickness different from the third predetermined thickness. The device of claim (3). (5) The device of claim (4), wherein the first and fifth thicknesses are equal and the second and fourth thicknesses are equal. (7) A reference geometry of the inner and outer surfaces. Claims (1), (2), and (4) in which the elements coincide with each other
or (5). (8) Claims (1) and (2), wherein the reference geometric elements of the inner and outer surfaces are offset from each other. The device according to paragraph (4) or paragraph (6). (9) The directions of the first and second regions are in the ST force direction,
The apparatus according to claim 4, wherein the direction of the fifth and fourth regions is the SST direction. OQ: said orientation of said first region provides a selected crystal lattice configuration consisting of said orientation of said second region has substantially the same crystal lattice configuration as said first region; Apparatus according to any one of the above clauses, wherein the direction of the first region forms a selected profile and provides a selected displacement with respect to a reference axis perpendicular to the longitudinal axis. , wherein the direction of the second region defines the contour of the first region and forms a displacement of 180° from the first displacement.
9) The device according to any one of paragraphs 9) to 9). (2) The contours of the first and second regions are flat. and said first displacement is selected from the group consisting of displacements around 40' and -49.2 degrees.
Equipment described in Section. 111 further comprising a first signal frequency means comprising the first region and a surface acoustic wave device formed therein, the first signal frequency means having selected temperature-frequency characteristics and pressure-frequency characteristics; I'm here. Further comprising second signal frequency means including the second region and a surface acoustic wave device formed therein. The temperature-frequency characteristic of the signal frequency means of this ship 2 is substantially the same as the temperature-frequency characteristic of the first signal frequency means, but the pressure-frequency characteristic thereof is the pressure-frequency characteristic of the first signal frequency means. The device according to any one of the preceding claims, wherein the frequency characteristics are selected. Q4 The first and second signal frequency means each include an oscillation circuit pressure-coupled to the surface acoustic wave device, a mixer connected to the output of the oscillation circuit, and a frequency counter connected to the output of the mixer. and a processor connected to the output of the frequency counter for determining a temperature compensated pressure measurement. σ9 The first region has a first switching temperature and the second region has a second switching temperature different from the first switching temperature. Device. 0e The direction of the first region is selected from the group consisting of directions around the nominal sT direction, the propagation direction across the first region is about 00, and the direction of the second region is about the nominal SS direction.
Selected from the group consisting of directions near the T direction, and the second
The device according to claim 05, wherein the direction of propagation in the region is approximately 21.5°. The 3 areas are: and the other surface is oriented in a force-selected direction to have a high sensitivity to pressure effects, a low sensitivity to temperature effects, and a fifth switching temperature, for a selected propagation direction consisting of: % surface acoustic wave device, the fourth region having a high sensitivity to pressure effects and a low sensitivity to temperature effects, for a selected direction of propagation, and said third switching. 152. The device according to claim 151 or aω, oriented in a selected direction to have a fourth switching temperature different from the temperature. 01 The directions of the first and third regions are selected from the group consisting of directions near the nominal ST length direction, the propagation directions in the first and third regions are approximately o6, and the directions of the second and third regions are approximately o6. %#'f The apparatus of claim 1, wherein the direction is selected from the group consisting of directions in the vicinity of the nominal SST direction, and the direction of propagation in the second and fourth regions is about 21.5°. 2. The apparatus of claim .alpha., wherein said first and fifth directions are illustratively the same and said second and fourth directions are substantially the same. The first and second regions have a planar profile, the first region being offset approximately 40° from a reference axis perpendicular to the longitudinal axis, and the second region being perpendicular to the longitudinal axis. The device according to claim 151 or an, offset from the reference axis by about −49.2°. Cl11 said first and second regions have a flat profile;
The first region is approximately 40° from the reference axis perpendicular to the longitudinal axis.
and the second region is offset about −14° from a reference axis perpendicular to the longitudinal axis. Shifted Claim 1 Clause G51 or Clause 19
Equipment described in Section. (23) The first and second regions have a flat profile. The first region has an angle of approximately 1.0 mm from the reference axis along the longitudinal axis.
20. A device according to claim 19, wherein the device is offset by 10.8' and said second region is offset by approximately -49.2° from a reference axis perpendicular to the longitudinal axis. ■ The first, @2% third and fourth regions have a flat profile and are approximately 40' and approximately 220 degrees from the reference axis perpendicular to the longitudinal axis of the first and sixth regions t'i, respectively. and wherein the second and fourth regions are offset approximately -49,2° and -229,2°, respectively, from a reference axis perpendicular to the longitudinal axis. Device. C141 Apparatus according to any one of claims 0◆ to 0, wherein the processor is connected to the output of the frequency counter so as to determine a temperature compensated pressure measurement of the weighted mold. . (c) The first V4 region has a selected crystal lattice structure which, for the first selected propagation direction, has a high sensitivity to pressure effects and a low sensitivity to temperature effects. 2. A device according to claim 1, wherein the device has a low sensitivity to pressure effects and a high sensitivity to temperature effects for the second selected propagation direction. (iv) a crystal lattice structure in the above region, the first propagation direction;
and the second propagation direction is SST direction 0°, 21.5
The device according to claim (c), wherein the discharge value is selected from the group consisting of: 55° Q O; an apparatus according to claim 1 or 4 in which the first propagation direction and the second propagation direction intersect. a structure having a commercial sensitivity to pressure effects and a low sensitivity to temperature effects for a third selected propagation direction, and a structure having a commercial sensitivity to pressure effects and a low sensitivity to temperature effects for a third selected propagation direction; has low sensitivity to pressure effects and high sensitivity to temperature effects,
The device according to item (c) or item C1'/1. Ql The crystal lattice structure of the first-mentioned region, the first propagation direction, and the second hypothetical direction are 0', 2i, 5° in the SST direction and 65°, 0° in the S T ij direction.
, and the crystal lattice structure of the second mentioned region, the third propagation direction, and the fourth propagation direction are selected from the group consisting of values around the SST direction o0.21.
5° and ST direction 55° Q Selected from the group consisting of values near OO! 4! jClaim No. 1 (device described in Santon. 1) The propagation direction of the upper fiem1 intersects with the 20th propagation direction, and the above-mentioned third propagation direction intersects with the 40th propagation direction r1'' Apparatus according to claim CG or E. 60. A crystalline diaphragm section having a cylindrical or spherical outer surface and a cylindrical or spherical inner surface, said outer surface having a given isotropic and said inner surface has a region of a selected crystal lattice structure comprising a surface wave signal frequency characterized in that said region is used to form a surface wave device. Apparatus.0z The apparatus of claim 60, wherein said diaphragm section has a continuous crystal lattice structure.