JP5648305B2 - Spherical surface acoustic wave device - Google Patents

Description

  The present invention relates to a spherical surface acoustic wave device that measures an environmental change factor from a change in propagation characteristics of a surface acoustic wave due to a difference in frequency using a spherical surface acoustic wave element.

  Conventionally, several spherical surface acoustic wave devices having different configurations have been proposed.

  One of the spherical surface acoustic wave devices has an annular region (hereinafter referred to as a circular path) on at least a part of the outer surface of the spherical shape, and a surface acoustic wave excited by a predetermined high-frequency signal circulates. A spherical surface acoustic wave element that continuously propagates and circulates along the path, and is disposed on or opposite to the circular path of the spherical surface acoustic wave element to excite the surface acoustic wave, and this excited surface The structure includes a surface acoustic wave excitation / detection unit that continuously circulates a wave along a circulation path and receives and outputs a signal generated from the circulating surface acoustic wave (Patent Document 1). ).

  A spherical surface acoustic wave element is a spherical base formed using a material that cannot excite a surface acoustic wave and including a circular path that circulates the surface acoustic wave on at least a part of the outer surface of the spherical shape. Formed by coating a material and a surface acoustic wave that circulates at least along a circular path on the outer surface of the spherical substrate with a material that can be excited, or using a material that can excite a surface acoustic wave At least a part of the spherical shape is formed so as to include a part constituting the circulation path on the outer surface.

Here, a piezoelectric material is usually used as a material capable of exciting a surface acoustic wave. However, when a spherical surface acoustic wave element is formed using a material capable of exciting a surface acoustic wave, for example, a quartz crystal is used. Piezoelectric crystal materials such as lithium niobate (LiNbO ₃ ), lithium tantalate (LiTaO ₃ ), langasite (La ₃ Ga ₅ SiO ₁₄ ) and their families are used. In this case, the circular path formed in at least a part of the spherical shape is on a line where the crystal plane of the piezoelectric crystal material intersects the outer surface, and the direction along the circular path is a substantially extending direction of the line. .

  The spherical surface acoustic wave element made of a piezoelectric crystal material is usually formed in a spherical shape having a diameter of about 1 mm to about 10 mm in consideration of material cost and frequency of adaptation.

  On the other hand, surface acoustic wave excitation / detection means have various configurations, but in consideration of manufacturing cost, device size, conversion efficiency, etc., so-called interdigital electrodes (also referred to as comb electrodes) are usually used. used.

  The interdigital electrode is composed of a pair of comb-shaped terminal portions, and has a shape in which a plurality of comb-shaped electrode branches constituting each comb-shaped terminal portion are opposed to each other, and is a spherical shape made of a piezoelectric crystal material. Directly formed by, for example, photolithography (photoengraving) on the part constituting the circulation path by at least a part of the spherical shape of the outer surface of the base material, or a blind that is separate from the spherical surface acoustic wave element of piezoelectric crystal material Photolithography (photoengraving) is performed on the inner surface of a partially spherical recess formed in a shape similar to the above-described portion constituting the circular path of the outer surface of the spherical base material made of the piezoelectric crystal material on the surface of the electrode support member After forming directly by the above, the above-mentioned portion of the circular path formed on the outer surface of the spherical base material is opposed to the part with a predetermined gap (1/4 or less of the wavelength of the surface acoustic wave to be excited). Arrangement It is.

  As an interdigital electrode, by applying a high-frequency burst signal of a predetermined frequency between a pair of comb-shaped terminal portions, the elasticity of a wavelength corresponding to the pattern or period between two adjacent comb-shaped electrode branches The surface wave can be excited in the circular path formed on the outer surface of the spherical substrate, and the width of the excited surface acoustic wave corresponds to the width at which the comb-like electrode branches intersect each other.

  In addition, the vertical direction of the plurality of comb-like electrode branches of the pair of comb-shaped terminal portions constituting the interdigital electrode is configured such that the wavefront of the surface acoustic wave excited as described above is formed on the outer surface of the spherical substrate. It becomes the direction which advances along a roundabout path. Therefore, in order to excite the surface acoustic wave by the interdigital electrode on the circular path formed on the outer surface of the spherical base material and propagate the surface acoustic wave along the circular path, a pair of comb shapes in the interdigital electrode The plurality of comb-like electrode branches of the terminal portion must be arranged perpendicular to the direction along the circulation path.

Furthermore, another spherical surface acoustic wave device has been proposed (Patent Document 2).
This spherical surface acoustic wave device excites in a direction orthogonal to the curvature of the circular path formed on the outer surface of the spherical surface acoustic wave element and the direction of the circular path (that is, the direction in which the excited surface acoustic wave propagates). The width of the surface acoustic wave (the length of the portion where the electrode branches of the interdigital electrode penetrate each other and face each other) and the frequency of the surface acoustic wave excited in the circuit path (arrangement of the multiple electrode branches of the interdigital electrode) By setting a predetermined item such as (period) and exciting a surface acoustic wave that circulates around the circuit path, the excited surface acoustic wave diffuses greatly in a direction that intersects the direction along the circuit path on the outer surface of the device. It can be made to circulate repeatedly without making it.

  A spherical surface acoustic wave element is provided with a sensitive film that is sensitive to changes in the external environment on the outer surface of a spherical base material made of a piezoelectric crystal material. Correspondingly, the propagation speed and attenuation rate of the surface acoustic wave that circulates in the circulation path change.

  Therefore, the surface acoustic wave excitation / detection means using the interdigital electrode detects the time required for one round of the surface acoustic wave of the excited high frequency burst signal and the change in the intensity of the surface acoustic wave every round. By doing so, it is possible to measure changes in the external environment, for example, gas concentration, so that it can be used as a physical quantity measuring device including a spherical surface acoustic wave element.

  For example, if the concentration of the gas to be detected increases, the circulatory velocity of the surface acoustic wave that circulates along the circulation path slows down due to the effect of the change in the sensitive film corresponding to this change in concentration. The time required for the wave to make one turn is longer. In addition, the strength of the surface acoustic wave is reduced every time it makes a round.

  Accordingly, a change in the rotation speed during one round of the surface acoustic wave travels, a change in the time required for the surface acoustic wave to make one round, a phase delay for each round of the surface acoustic wave, and a surface There is a slight change, such as a decrease in the intensity of the output generated from the wave. As a result, as the number of times that the surface acoustic wave circulates in the circulation path increases, the above-described change is superimposed and increased. Therefore, the measurement accuracy of various signal changes corresponding to the change in the external environment is improved by the surface acoustic wave circulating around the circulation path.

  This is because when the change in the external environment is measured using the spherical surface acoustic wave element as described above, it is preferable that the vibration energy of the surface acoustic wave that circulates in the circulation path changes due to factors other than the change in the external environment. Clearly not.

  By the way, when the interdigital electrode is used as the conventionally known surface acoustic wave excitation / detection means applied to the spherical surface acoustic wave element as described above, as described in the former of Patent Document 1, the interdigital path is used. When the electrode is directly formed, the excited surface acoustic wave propagating along the circular path on the outer surface of the spherical base material made of the piezoelectric crystal material by the interdigital electrode is circulated along the circular path on the outer surface. There is a problem in that vibration energy is lost due to scattering due to the influence of reflection due to the mass of the interdigital electrode.

  This is because, in the case where a comb electrode is used in a conventionally known surface acoustic wave excitation / detection means applied to a spherical surface acoustic wave element, as described in the latter of Patent Document 1, the spherical shape of the piezoelectric crystal material is used. The inner surface of a partially spherical recess formed on the surface of an interdigital electrode support member that is separate from the surface acoustic wave element and shaped like a circular path formed on the outer surface of a spherical base material of piezoelectric crystal material After forming the interdigital electrode directly, it is preferable to arrange the interdigital electrode so as to face the circular path formed on the outer surface of the spherical substrate with a predetermined distance.

Furthermore, another spherical surface acoustic wave device that measures a desired physical quantity by exciting a surface acoustic wave has been proposed (Patent Document 3).
This spherical surface acoustic wave device forms interdigital electrodes that excite a plurality of frequencies in a spherical base material of a piezoelectric crystal material constituting a spherical surface acoustic wave element, and, for example, frequencies in a plurality of different bands of 50 MHz and 150 MHz. Is used to excite a surface acoustic wave that circulates, and a signal generated from the excited surface acoustic wave that circulates is detected by each interdigital electrode.

  In recent years, measurement methods for exciting / detecting surface acoustic waves in a plurality of frequency bands have been used, and such spherical surface acoustic wave elements are called harmonic elements.

  When surface acoustic waves propagate (circulate) the surface of a spherical base material of piezoelectric crystal material, if the frequency increases, the mass load near the surface, the change in the mass load, or the change in the physical properties of the sensitive film Because of the large influence on the propagation speed and damping constant of surface acoustic waves, due to the difference in response due to the difference in frequency, the fluctuation component due to the fluctuation factors existing only near the surface and the fluctuation due to other environmental change factors The component is measured separately.

  Usually, if the rate of change of the propagation speed of the surface acoustic wave of the high frequency component is almost the same as the rate of change of the propagation speed of the surface wave of the low frequency component, it is determined that the dependence on the frequency is essentially small, When measuring changes due to the temperature dependence of the spherical base material of the piezoelectric crystal material exclusively, or when the propagation speed of surface acoustic waves with high frequency components has changed significantly, the fluctuation factors that exist only near the surface, for example It is possible to detect the adhesion of molecules to the surface. In other words, the factors can be analyzed by solving simultaneous equations composed of variables due to two environmental variation factors based on the difference in frequency.

  By the way, as described above, when measuring a change in the circumferential velocity of the surface acoustic wave and a change in the attenuation rate, etc., using frequencies in different bands, the interdigital electrode is a double finger electrode (see FIG. 2). Is often used. It is known that the double finger electrode efficiently excites a surface acoustic wave having a frequency ratio of 1: 3: 5 and detects a change in the rotation speed.

  Double finger electrodes have the advantage of being able to excite surface acoustic waves of multiple frequencies with a single electrode pattern, but cannot have any number of electrode branches for frequency differences, In addition, when an electrode having a certain frequency is approached, another frequency electrode is also approached, which has a problem of affecting the surface acoustic wave having that frequency.

  In some cases, a plurality of simple interdigital electrodes are formed corresponding to a plurality of frequencies on the circulation path around the surface acoustic wave, but the excited surface acoustic waves do not pass through the interdigital electrode many times. must not. In particular, a component having a high frequency has a problem that the excited surface acoustic wave cannot circulate many times because it is repeatedly attenuated and reflected due to the presence of the interdigital electrode pattern.

  Therefore, as an interdigital electrode, in order to excite a low-frequency surface acoustic wave component, it is possible to increase the measurement accuracy by forming it on the outer surface of the spherical base material over a long distance on the circular path, but the high frequency In the case of the surface acoustic wave, there is a problem that the surface acoustic wave is attenuated when passing through the electrode.

Japanese Patent Laying-Open No. 2005-094609 International Publication WO 01/45255 JP 2006-071482 A

  Therefore, when measuring the surface of the spherical surface acoustic wave element and the surrounding gas environment by exciting and detecting surface acoustic waves in a plurality of frequency bands as described above, interdigital electrodes capable of exciting frequencies in a plurality of bands If the interdigital transducers are used, or different interdigital electrodes are formed for each frequency band, the surface acoustic wave is greatly attenuated each time it passes through each interdigital transducer. As a result, the number of circulations of the circulation path cannot be extended, and as a result There is a problem that accuracy decreases.

  The present invention has been made in view of the above circumstances, and uses a high-frequency signal in a plurality of frequency bands to excite and detect a surface acoustic wave in a circular path of a spherical surface acoustic wave device, and to detect an elastic surface due to a difference in frequency. An object of the present invention is to provide a spherical surface acoustic wave device that accurately measures environmental changes from changes in wave propagation characteristics.

In order to solve the above problems, the spherical surface acoustic wave device of the present invention includes:
A spherical surface acoustic wave element in which a circular path is formed on at least a part of the outer surface of the spherical shape and the surface acoustic wave propagates along the circular path when excited by a high frequency burst signal;
High-frequency burst signal generating means for generating a plurality of high-frequency burst signals of different frequencies:
Interdigital electrodes of two surface acoustic wave excitation / detection means supported by the two relative distance adjustment means so as to be relatively movable facing the circular path of the spherical surface acoustic wave element;
Two relative distance adjusting means arranged at a predetermined angle with each other along the circular path of the spherical surface acoustic wave element, and arranged opposite to the circular path ; and the two relative distance adjusting means; Two interdigital electrodes of the surface acoustic wave excitation / detection means that are supported so as to be relatively movable facing the circular path of the spherical surface acoustic wave element;
The two relative distance adjusting means are instructed to move the two surface acoustic wave excitation / detecting means with respect to the circular path of the spherical surface acoustic wave element, and one of the two relative distance adjusting means is provided. A surface acoustic wave is applied to the circular path of the spherical surface acoustic wave element by a comb electrode of one of the surface acoustic wave excitation / detection means supported by a selected one of the plurality of high frequency burst signals having different frequencies. The relative distance adjustment of the one when excited and continuously propagated along the circuit path and when a signal generated from a surface acoustic wave that has circulated the circuit path a predetermined number of times is detected and output as a received signal The interdigital electrode of the one surface acoustic wave excitation / detection means is brought close to the circular path by means of the interdigital electrode of the one surface acoustic wave excitation / detection means. Serial the one of the surface acoustic wave excitation and the surface acoustic waves the orbiting interdigital transducer away from the circular path of the sensing means electromagnetic influences the surface acoustic wave in the circumferential path after starting the circulation by pumping Selected from the plurality of high frequency burst signals of different frequencies by the interdigital electrode of the other surface acoustic wave excitation / detection means supported on the other of the two relative distance adjustment means. When another surface acoustic wave is excited in the circular path of the spherical surface acoustic wave element and continuously propagated along the circular path and circulated, and from the surface acoustic wave that has circulated the circular path a predetermined number of times When the generated signal is detected and output as a reception signal, the other surface-wave excitation / detection means of the interdigital electrode of the other surface acoustic wave excitation / detection means is performed by the other relative distance adjustment means. Is near, interdigital electrodes of the other surface acoustic wave excitation and detection means after the to initiate circulates a surface acoustic wave is excited in the circular path at interdigital electrodes of the other surface acoustic wave excitation and detection means The surface acoustic wave that circulates away from the circuit path is not affected electromagnetically,
Furthermore, the approach of the interdigital electrode of the one surface acoustic wave excitation / detection means by the one relative distance adjusting means with respect to the circular path and the other surface acoustic wave by the other relative distance adjusting means with respect to the circular path. Performing the approach of the interdigital electrode of the excitation / detection means at a different time,
Desirable from change in propagation characteristics of the surface acoustic wave due to a difference in frequency between the signal detected by the one surface acoustic wave excitation / detection means and the signal detected by the other surface acoustic wave excitation / detection means A control processing system that measures environmental changes;
It is provided with.

  According to the present invention, a surface acoustic wave is excited and detected in a circular path of a spherical surface acoustic wave element using high-frequency signals in a plurality of frequency bands, and the environment changes from a change in surface acoustic wave propagation characteristics due to a difference in frequency. Can be provided with a spherical surface acoustic wave device.

The block diagram which shows 1st Embodiment of the spherical surface acoustic wave apparatus which concerns on this invention. The top view of the interdigital electrode used for the spherical surface acoustic wave apparatus shown in FIG. FIG. 5A shows the attenuation state of the surface acoustic wave that propagates around the circular path of the spherical surface acoustic wave element, and FIG. 5B shows the surface acoustic wave that has made a predetermined number of rounds around the circular path. The figure explaining a mode that the phase of a detection signal is changed according to the change of. The flowchart explaining the operation | movement procedure of the spherical surface acoustic wave apparatus which concerns on this invention. The flowchart explaining the operation | movement procedure of the spherical surface acoustic wave apparatus following FIG. The top view of the interdigital electrode used for every some frequency band. The block diagram which shows 2nd Embodiment of the spherical surface acoustic wave apparatus which concerns on this invention.

Embodiments of the present invention will be described below with reference to the drawings.
(First embodiment)
FIG. 1 is a block diagram showing a first embodiment of a spherical surface acoustic wave device according to the present invention.
This spherical surface acoustic wave device includes a spherical surface acoustic wave element 1, a surface acoustic wave excitation / detection means 2, a relative distance adjustment means 3, and a control processing system 4.

  In the spherical surface acoustic wave element 1, an annular region (hereinafter referred to as a circular path) 11 is formed using at least a part of the outer surface of a spherical shape, and is excited to the circular path 11 from the outside by a high frequency burst signal. The surface acoustic wave 12 has a function of propagating along the circulation path 11 to make a number of rotations.

  The spherical surface acoustic wave element 1 in this embodiment is formed in a spherical shape having a diameter of 3.3 mm using quartz which is a kind of piezoelectric material, and the circular path 11 formed on the outer surface of the spherical shape is spherical. When the surface acoustic wave element 1 is regarded as the earth, it exists so as to make a round around the equator with the Z axis, which is the crystal axis of crystal, as the ground axis (Z axis cylinder).

  The spherical surface acoustic wave element 1 has a spherical shape. However, for example, both outer portions of the circulation path 11 may be flat and may have a so-called disk shape.

  In the spherical surface acoustic wave element 1, the outer surface of the lower end of the element is supported by a support base 13 in a direction orthogonal to the circulation path 11 around which the surface acoustic wave 12 circulates, and the circulation path 11 is located in a horizontal plane. ing.

  The surface acoustic wave excitation / detection means 2 is supported by the support 21 so as to face the circular path 11 of the spherical surface acoustic wave element 1 with a desired distance therebetween. The surface acoustic wave excitation / detection means 2 excites a surface acoustic wave 12 that circulates around the circulation path 11 and continuously circulates the excited surface acoustic wave 12 along the circulation path 11. It has a function of detecting a signal generated from an incoming surface acoustic wave and outputting it as a received signal.

  The support 21 is formed in a predetermined shape from fused quartz, and the surface facing the circular path 11 of the spherical surface acoustic wave element 1 is formed in a curved shape by a part of a spherical surface similar to the circular path 11. The curvature radius of the curved surface may be formed to 3.3 mm which is exactly the same as the curvature radius of the circulation path 11, but in this embodiment, the curvature radius is set to 3.5 mm. This is because if the thickness is 3.3 mm, the surface acoustic wave excitation / detection means 2 can be brought close to the circulation path 11 as much as possible, but the support 21 is slightly along the surface of the circulation path 11 of the surface acoustic wave 12. However, if the position is shifted, the surface acoustic wave excitation / detection means 2 comes into contact with the circulation path 11. That is, there is an advantage that the above contact can be prevented by creating the curved surface of the surface of the support 21 with a large curvature radius as described above.

  The relative distance adjusting means 3 is configured to support at least one of the spherical surface acoustic wave element 1 and the surface acoustic wave excitation / detection means 2 so as to be movable relative to the other. In the present embodiment, the support 21 of the surface acoustic wave excitation / detection means 2 is movably supported. That is, the relative distance adjusting means 3 is excited in the circulation path 11 by the surface acoustic wave excitation / detection means 2 by adjusting the distance between the spherical surface acoustic wave element 1 and the surface acoustic wave excitation / detection means 2. The intensity of the surface acoustic wave 12 is changed, or the intensity of the received signal that is detected and output from the surface acoustic wave 12 that the surface acoustic wave excitation / detection means 2 circulates is changed.

  Here, the reason why the relative distance adjusting means 3 adjusts the distance is as follows. When the surface acoustic wave excitation / detection means 2 excites and detects frequencies in a plurality of bands, the wavelength of the high frequency (150 MHz in this example) is 1 / of the wavelength of the surface acoustic wave 12 because the wavelength of the high frequency is shorter. It is desirable to approach the distance of 4 or less. Therefore, by bringing the surface acoustic wave excitation / detection means 2 closer to the circulation path 11, the surface acoustic wave 12 can be generated with a large intensity without changing the intensity of the high-frequency signal applied to the surface acoustic wave excitation / detection means 2. This is because a relatively large received signal can be obtained from the surface acoustic wave 12 even when the excitation is performed in the circulation path 11 or the number of circulations of the surface acoustic wave 12 increases and the strength decreases.

  Conversely, by moving the surface acoustic wave excitation / detection means 2 away from the circulation path 11, the surface acoustic wave excited in the circulation path 11 without changing the intensity of the high-frequency signal applied to the surface acoustic wave excitation / detection means 2. The intensity of 12 is reduced, or a relatively small received signal is obtained without using an attenuator from the surface acoustic wave 12 having a small number of laps in the circulation path 11 and a high intensity. It is possible to prevent an input from entering, and thus to prevent waveform distortion of the received signal.

  Specifically, the relative distance adjusting means 3 is attached to a fixed pedestal (not shown), and is a coarse relative distance adjusting stage capable of moving forward and backward greatly in a direction facing the circular path 11 of the spherical surface acoustic wave element 1. 31, a four-direction position adjustment stage 32 movably provided in four directions with respect to the coarse movement relative distance adjustment stage 31, and the spherical surface acoustic wave element 1 supported by the four-direction position adjustment stage 32. And a minute relative distance adjusting means 33 that can be moved forward and backward in a direction facing the circular path 11 of the substrate, and supporting the surface acoustic wave excitation / detecting means 2 at the tip of the minute relative distance adjusting means 33 A body 21 is attached.

  That is, the coarse relative distance adjustment stage 31 and the minute relative distance adjustment means 33 move in the left-right direction on the paper surface of FIG. 1, and the four-direction position adjustment stage 32 is along the two directions in the direction orthogonal to the paper surface and the paper surface. Move in two directions, up and down. Two directions perpendicular to the paper surface are indicated by a circle with a black dot center and a circle with a batten, and two vertical directions along the paper surface are indicated by white double-headed arrows.

  The minute relative distance adjusting means 33 is constituted by, for example, a known piezoelectric operation member (so-called piezoelectric actuator). The output of the amplifier 35 is applied to the piezoelectric operation member via a control signal generator 34 from a central control device 41 such as a CPU (Central Processing Unit) that constitutes a control processing system 4 that controls the overall control of the entire device. The

  That is, the piezoelectric operation member moves the support 21 forward and backward in the radial direction of the circulation path 11 with an accuracy of 0.01 micron according to the value of the DC voltage applied from the control signal generator 34 through the amplifier 35. Can do. The minute relative distance adjusting means 33 may include a material member that deforms and moves when a predetermined voltage signal is received from the amplifier 35.

  The control processing system 4 is based on a frequency selection command from the central control unit 41, and a high frequency burst signal generator 42 that selectively generates high frequency burst signals of two frequencies (50 MHz and 150 MHz), and the generation of the high frequency burst signal. A high frequency burst signal having a first frequency (for example, 150 MHz) is applied to the interdigital electrode of the surface acoustic wave excitation / detection means 2 for a predetermined time from the device 42, and the surface acoustic wave 12 (in this embodiment) A circulator 43 for exciting and propagating a Rayleigh wave and detecting a signal generated from the circulating surface acoustic wave 12 with an interdigital electrode and outputting the output signal. The amplifier 44 amplifies the signal at a predetermined amplification degree, controls the operation of the entire apparatus according to a predetermined procedure, and the amplifier 4 4 includes a central control device 41 that takes in the amplified signal through the digitizer 45 and measures a desired environmental change from a change in surface acoustic wave propagation characteristics due to a difference in frequency band, and a display unit 46. .

  FIG. 2 is a view showing the interdigital electrode 2 a of the surface acoustic wave excitation / detection means 2 formed on the curved surface of the support 21.

  As the surface acoustic wave excitation / detection means 2, an interdigital electrode 2a of a type called a double finger electrode capable of exciting / detecting a plurality of frequencies (50 MHz and 150 MHz) is formed. This interdigital electrode 2a is formed by depositing a 1000 angstrom thick chromium adhesive layer on the curved surface, depositing gold on the angstrom thickness to 2000 angstrom, and patterning it to a predetermined dimension by photolithography. Is formed. The widths of the line portions and the space portions of the plurality of electrode branches of the interdigital electrode 2a are approximately 21.3 microns, and the frequency bands are set to 50 MHz and 150 MHz.

  Further, each of the plurality of electrode branches extends on the curved surface of the support 21 in a direction orthogonal to the extending direction of the circular path 11 that is virtually represented, and the arrangement direction of the plurality of electrode branches extends in the extending direction. It is formed to be in the direction.

Next, the operation procedure of the spherical surface acoustic wave device as described above will be described with reference to FIGS.
First, before measuring a change in the external environment with the spherical surface acoustic wave device, the four-direction position adjusting stage 32 of the relative distance adjusting means 3 is used to center the circumferential path 11 of the spherical surface acoustic wave element 1 in the width direction. On the other hand, the center of the interdigital electrode 2a (that is, the center in the width direction of the plurality of electrode branches that overlap each other in the arrangement direction) coincides, and the curved surface of the support 21 is parallel to the circulation path 11. The relative position of the support body 21 with respect to the circulation path 11 is adjusted so as to face the surface. Further, the curved relative surface of the support 21 (that is, the interdigital electrode 2a) is located in the vicinity of the circulation path 11 with respect to the circulation path 11 of the spherical surface acoustic wave element 1 by the coarse movement relative distance adjustment stage 33. The distance from the path 11 is ¼ or less of the wavelength of the surface acoustic wave 12 of the high frequency (150 MHz) on which the interdigital electrode 2a is excited. Incidentally, in this example, it is made close to 3 microns, which is a position shorter than 7.1 microns.

  In the position setting as described above, an excitation / detection control instruction is issued from the central control device 41, the positions of the four-direction position adjustment stage 32, the coarse movement relative distance adjustment stage 33, and the like are controlled, and the interdigital electrode 2a is turned around. The state which can be excited and detected is produced | generated by approaching 11 desired distance.

  Next, on the basis of a signal generation command from the central controller 41, a high frequency burst having a frequency of 150 MHz is passed from the high frequency burst signal generator 42 through the circulator 43 for a predetermined time (0.3 microsecond in this embodiment). A signal is sent out and applied to the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 so that the surface acoustic wave 12 is excited and propagated in the circulation path 11. At this time, the surface acoustic wave 12 makes one round of the circulation path 11 in about 3.1 microseconds and makes a number of revolutions.

  Here, applying a high-frequency burst signal having a predetermined frequency to the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 for a predetermined time is a plurality of positions relative to the circular path 11 (that is, from the circular path 11). This means that the high-frequency burst signal having a plurality of intensities corresponding to the interdigital electrodes 2a) is applied.

  FIG. 3 shows a state in which the intensity of the surface acoustic wave attenuates as it circulates around the circulation path 11 (FIG. 3a), and the surface acoustic wave that has circulated a number of times changes the phase of the output signal in accordance with changes in the external environment. It is a figure which represents a mode (same figure b) roughly.

  That is, FIG. 3A shows the attenuation state of the signal intensity of the surface acoustic wave 12 when the surface acoustic wave 12 circulates 50 times along the circulation path 11. On the other hand, FIG. 3B shows the output waveform of the received signal when the surface acoustic wave 12 that circulates around the circular path 11 makes 50 laps before exposing the circular path 11 of the spherical surface acoustic wave element 1 to the external environment. Is indicated by a solid line, and the output waveform of the received signal when the surface acoustic wave 12 that circulates around the circular path 11 is exposed 50 times after the circular path 11 of the spherical surface acoustic wave element 1 is exposed to the external environment is indicated by a dotted line. It is represented by.

  As apparent from FIG. 3B, it can be understood that the propagation speed of the surface acoustic wave 12 propagating on the circulation path 11 is influenced by the influence of the external environment, and the phase change G occurs.

  Here, for the convenience of illustration, the size of the solid line waveform and the dotted line waveform (longitudinal amplitude) are drawn the same, but the solid line waveform and the dotted line are within the measurable range of the digitizer 45. The difference in waveform size (amplitude in the vertical direction) can be measured accurately.

  Next, the operation sequence of the spherical surface acoustic wave device when actual measurement of the external environment is performed will be described with reference to FIGS.

  First, a positioning command is sent to the control signal generator 34 in order to place the interdigital electrode 2a at one of the predetermined positions (hereinafter referred to as the first predetermined position) from the central controller 41. The control signal generator 34 applies one predetermined voltage value DV to the minute relative distance adjusting means 33 through the amplifier 35. At this time, the interdigital electrode 2a is set to the initial position facing the circuit path 11 by the initial setting of the coarse movement relative distance adjustment stage 31 and the four-direction position adjustment stage 32 described above.

  Therefore, when a predetermined voltage value DV is applied, the minute relative distance adjusting means 33 is a minute distance in the radial direction of the circulation path 11 in accordance with the voltage value DV so as to correspond to a high-frequency burst signal having a higher frequency. The interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 formed on the curved surface of the surface of the support 21 is set at a first predetermined position with respect to the circular path 11 of the spherical surface acoustic wave element 1. ST1).

  Thereafter, a high frequency burst signal having a predetermined frequency (for example, 150 MHz) is generated from the high frequency burst signal generator 42 for a predetermined duration based on a signal generation command from the central control device 41, and elastically transmitted through the circulator 43. It is applied to the interdigital electrode 2a of the surface wave excitation / detection means 2. As a result, the interdigital electrode 2a has a predetermined strength with respect to the circular path 11 of the spherical surface acoustic wave element 1 facing through a predetermined distance (referred to as a first predetermined distance) according to the voltage value DV. The surface acoustic wave 12 is excited and propagated along the circulation path 11 to start circulation.

  After the high frequency burst signal is applied to the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 and the above-mentioned predetermined duration elapses, the interdigital electrode 2a affects the surface acoustic wave 12 propagating on the circular path 11. In order not to give it, the voltage value DV applied to the minute relative distance adjusting means 33 is stopped, and the interdigital electrode 2a is moved from the circuit path 11 to the initial position (ST2).

  And it waits until the time when the surface acoustic wave 12 goes around the circulation path 11 five times. In the present embodiment, the time is 3.1 (μ seconds) × 5 rounds = 15.5 (μ seconds) from the start of excitation of the surface acoustic wave 12 (ST3).

  Further, a positioning command is sent from the central control device 41 to the control signal generator 34 in order to arrange it at a distance suitable for detecting the received signal from the surface acoustic wave 12 that has made five turns. The control signal generator 34 applies a predetermined voltage value EV to the minute relative distance adjusting means 33 via the amplifier 35 (ST4). As a result, according to the voltage value EV, the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 formed on the curved surface of the support 21 with respect to the circular path 11 of the spherical surface acoustic wave element 1 is predetermined. It is moved to the other position (hereinafter, referred to as a second predetermined position) and arranged at a distance suitable for detecting the received signal from the surface acoustic wave 12 (ST4).

  When the surface acoustic wave 12 that has made five revolutions in the circulation path 11 arrives, a signal generated from the surface acoustic wave 12 is detected by the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 and output as a received signal. The output reception signal is sent to the central control device 41 via the circulator 43, the amplifier 44, and the digitizer 45. The central control device 41 performs a process necessary for grasping a change in the external environment, and then displays it on the display unit 46 (ST5).

  The central controller 41 confirms whether or not the received signal of the fifth round is within a predetermined intensity range (ST6). Here, when the received signal of the fifth round exceeds a predetermined intensity range, a predetermined time during which the surface acoustic wave 12 that circulates the circulation path 11 is not detected by the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 is detected. Later (ST7), the process returns to step ST1 again, and the above-described series of processing is repeatedly executed.

  At this time, in step ST4, the central control device 41 applied to the minute relative distance adjusting means 33 of the relative distance adjusting means 3 from the control signal generator 34 via the amplifier 35 in the previous step ST4. A voltage value (updated voltage value EV) weaker than the voltage value EV by a predetermined amount is applied, and the distance of the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 with respect to the circulation path 11 of the spherical surface acoustic wave element 1 is determined. Increase by a predetermined value.

  As a result, a high frequency burst signal having a predetermined frequency is generated from the high frequency burst signal generator 42 for a predetermined duration in the present step ST1, and the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 is connected to the interdigital electrode 2a via the circulator 43 last time. When the surface acoustic wave 12 of the 5th turn is detected in this step ST5 again while exciting the sufficiently strong surface acoustic wave 12 with the same predetermined intensity as in FIG. Since it faces the circular path 11 via a distance (referred to as a second predetermined distance) that is longer than the predetermined distance at the time of detection, the received signal from the surface acoustic wave 12 of the fifth round is received. It is possible to prevent the output from exceeding the measurement allowable range of the digitizer 45 and to prevent the measurement result of the output of the received signal from becoming inaccurate.

  Contrary to the above in step ST6, if the received signal in the fifth round is smaller than the predetermined intensity range, the process returns to step ST1 via step ST7 and again proceeds to step ST4. At this time, in step ST4, one predetermined voltage value EV applied from the control signal generator 34 via the amplifier 35 to the minute relative distance adjusting means 33 of the relative distance adjusting means 3 in the previous step ST4. It is possible to increase the distance of the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 with respect to the circular path 11 of the spherical surface acoustic wave element 1 by a predetermined value. Absent.

  By the way, when it is confirmed in step ST6 that the received signal in the fifth round is within a predetermined intensity range, the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 generates the surface acoustic wave 12 that circulates around the circulation path 11. After the elapse of a predetermined time (eg, 1 millisecond) that is no longer detected (ST8), the processing of steps ST9 to ST14 having the same contents as the above-described steps ST1 to ST5 is performed.

  That is, one of the two predetermined positions of the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 formed on the curved surface of the support 21 with respect to the circular path 11 of the spherical surface acoustic wave element 1 is described above. In order to arrange at a certain first predetermined position, a positioning command is sent from the central control device 41 to the control signal generator 34. As a result, one predetermined voltage value DV is applied from the control signal generator 34 to the minute relative distance adjusting means 33 via the amplifier 35 (ST9).

  Next, a high frequency burst signal having a predetermined frequency is generated from the high frequency burst signal generator 42 for a predetermined duration, and the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 is passed through the circulator 43 to the previous step ST2. It is applied with the same predetermined intensity as in the case of. As a result, the interdigital transducer 2a has the same predetermined distance as the previous predetermined distance (first predetermined distance) and is facing the circular path 11 of the spherical surface acoustic wave element 1 facing the same distance as the previous one. The surface acoustic wave 12 having a predetermined intensity is excited (ST10), propagated along the circulation path 11, and the circulation starts.

  Thereafter, the central control unit 41 determines the predetermined relative distance adjustment means 33 through the control signal generator 34 so that the surface acoustic wave excitation / detection means 2 does not affect the surface acoustic waves 12 propagating on the circulation path 11. The interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 is moved to an initial position (referred to as a third predetermined distance) away from the circulation path 11 (ST11).

  Here, it waits until the time when the surface acoustic wave 12 makes five revolutions around the circulation path 11. In the present embodiment, this time is 3.1 (μ seconds) × 5 rounds = 15.5 (μ seconds) from the start of excitation of the surface acoustic wave 12 (ST12).

  Further, a positioning command is sent from the central control device 41 to the control signal generator 34 in order to arrange it at a distance suitable for detecting the received signal from the surface acoustic wave 12 that has made five turns. The control signal generator 34 outputs a predetermined voltage value EV via the amplifier 35 and applies it to the minute relative distance adjusting means 33 (ST13).

  When the surface acoustic wave 12 that has made five revolutions in the circulation path 11 arrives, a signal generated from the surface acoustic wave 12 is detected by the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 and output as a received signal. The output reception signal is sent to the central control device 41 via the circulator 43, the amplifier 44, and the digitizer 45. The central control device 41 measures at least the phase of the received signal received, further processes the signal according to a change in the external environment to be measured, and displays it on the display unit 46 (ST14).

  The central control device 41 receives the reception signal of the fifth round and performs necessary processing, and then the voltage value already applied through the control signal generator 34 to the minute relative distance adjustment means 33 of the relative distance adjustment means 3. Stop EV. That is, the voltage value is set to 0 V (ST15).

  As a result, the minute relative distance adjusting means 33 of the relative distance adjusting means 3 uses the interdigital electrode 2 a of the surface acoustic wave excitation / detection means 2 formed on the curved surface of the support 21 as the spherical surface acoustic wave element 1. It is moved from the circulation path 11 to a predetermined initial position (ST15).

  As a result, the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 is not affected by the surface acoustic wave 12 that circulates in the circulation path 11, and receives signals from the surface acoustic wave 12 that circulates. Is not detected. This is because the surface acoustic wave 12 that circulates around the circulation path 11 has no influence from the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 that exists at an initial position sufficiently away from the circulation path 11. It means not to receive.

  In the present embodiment, as described above, the diameter of the circular path 11 of the spherical surface acoustic wave element 1 is 3.3 mm, and the surface acoustic wave 12 excited in the circular path 11 by the high frequency burst signal of 150 MHz is the circular path. The time required to make 11 rounds is approximately 3.1 microseconds.

  Therefore, in the device of the present invention, after approximately 155 microseconds (approximately 3.1 microseconds (1 round) × 50 laps) required until the surface acoustic wave 12 starts to circulate the circulation path 11 and makes 50 laps have elapsed. (ST16) In order to move the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 from the initial position described above to the first predetermined position described above, the central control device 41 performs a minute adjustment of the relative distance adjustment means 3. A voltage value DV is applied from the control signal generator 34 via the amplifier 35 to the relative distance adjusting means 33 (ST17).

  The interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 disposed again at the first predetermined position again detects the surface acoustic wave 12 circulating around the circular path 11 of the spherical surface acoustic wave element 1, and the detection thereof. A reception signal corresponding to the surface acoustic wave 12 is generated and sent to the central controller 41 through the circulator 43, the amplifier 35, and the digitizer 45.

  Central controller 41 measures at least the phase of the received signal received from digitizer 45 (ST18).

  The central control unit 41 or the surface acoustic wave excitation / detection means 2 knows the number of the surface acoustic wave 12 from the elapsed time from the time when the surface acoustic wave 12 is excited to start the circulation. Can do.

  In step ST13, in order to detect the surface acoustic wave 12 in the fifth round, the control signal from the central controller 41 is used to move the surface acoustic wave excitation / detection means 2 from the initial position to the second predetermined position. A predetermined voltage value DE is applied to the minute relative distance adjusting means 33 through the generator 34 and the amplifier 35. In step ST17, a control signal is generated from the central controller 41 in order to detect the surface acoustic wave 12 on the 50th lap. Since a voltage value DV larger than the predetermined voltage value DE is applied to the minute relative distance adjusting means 33 through the device 34 and the amplifier 35, the surface acoustic wave excitation / detection means 2 is further brought closer to the circulation path 11 than in step ST13. It is possible to detect the surface acoustic wave 12 whose strength has been attenuated and weakened with an increase in the number of turns with sufficient strength and send it to the central controller 41 as a received signal. That.

  Thereafter, the central control device 41 eliminates the surface acoustic wave 12 that circulates around the circular path 11 of the spherical surface acoustic wave element 1 or passes through the surface acoustic wave excitation / detection means 2 disposed at the first predetermined position. After a lapse of a predetermined time (for example, 1 millisecond) sufficient to reduce the intensity of the surface acoustic wave 12 detected by the electrode 2a (ST19), it is determined how many times the change in the external environment has been measured. Judgment is made (ST20).

  If the predetermined number of rounds has not been measured, the process returns to step ST10, and the same process is repeated, and the received signal from the surface acoustic wave 12 of the 50th round whose intensity is attenuated is obtained with a large output. In addition, since it can be further averaged, it can be obtained and displayed with high accuracy.

  Therefore, according to the embodiment of the present invention, the received signal detected by the interdigital electrode 2a of the surface acoustic wave excitation / detection means 2 under the change of the external environment using the spherical surface acoustic wave device as described above. If the measurement is performed, a change in the external environment is compared with, for example, the intensity and phase of the output signal in the surface acoustic wave 12 on the fifth round, and the intensity and phase of the output signal in the surface acoustic wave 12 on the 50th round are accurately measured. It can be measured. As a result, by using the intensity and phase of the output signal in the surface acoustic wave 12 at the 50th turn, it is possible to accurately measure the intensity and phase of the output signal having a small number of turns and a high intensity, such as the fifth turn. It is clear that the attenuation rate of the surface acoustic wave 12 per round can be accurately obtained. The phase can be accurately measured even when the phase of the high-frequency signal applied to excite the surface acoustic wave 12 is unstable due to the difference between the phase at the fifth round and the phase at the 50th round. As a result, the propagation velocity of the circulating surface acoustic wave 12 can be measured more accurately.

  The measurement of the change in the external environment described above has been described with respect to the specific operation when exciting and detecting the surface acoustic wave 12 using the high-frequency burst signal having a frequency of 150 MHz. Using the signal, the change in the external environment is similarly measured.

  In general, the time required for the surface acoustic wave 12 to make one round of the circulation path 11 does not change greatly. However, as the frequency of the surface acoustic wave 12 decreases, the attenuation of the strength of the surface acoustic wave 12 associated with the rotation decreases. For example, in order to obtain the same accuracy as the signal measurement at the 50th round at 150 MHz, the surface acoustic wave 12 is propagated and measured over a time of about 3.1 microseconds (one round) × 150 rounds = about 456 microseconds. By doing so, the accuracy of phase measurement can be increased.

  The distance of the surface acoustic wave excitation / detection means 2 to the loop path 11 when using a high-frequency burst signal with a frequency of 50 MHz may be more distant from that of the high-frequency burst signal with a frequency of 150 MHz, but the distance is measured. What is necessary is just to change so that the signal to perform may be obtained with sufficient SN ratio.

  The central control device 41 can measure the surface state as a reference and the surface acoustic wave velocity and the attenuation constant in a state in which foreign matter has adhered to the surface for each of the two frequencies described above. From the rate of change of the phase velocity, it is possible to determine the factor of the temperature environment change and the factor of foreign matter adhering to the surface.

  The operation procedure for measuring the rotational speed and attenuation (intensity) of the surface acoustic wave 12 at a frequency of 50 MHz can be performed according to FIGS. 4 and 5 as in the case of the frequency of 150 MHz. It is possible to measure. That is, the high frequency burst signal generator 42 generates high frequency burst signals having two frequency components of 50 MHz and 150 MHz, and simultaneously generates surface acoustic waves having two frequencies of 50 MHz and 150 MHz on the surface of the piezoelectric crystal sphere (crystal). It can be excited and propagated.

  After that, at the time of the fifth round, the interdigital electrode 2a is brought close to the surface of the piezoelectric crystal sphere (quartz) for a short time (a time corresponding to one round), and the surface acoustic wave signals of two frequencies are measured. Later, the signal that passed through the filter that allows only the 150 MHz component signal to pass is measured as the measurement result of the 150 MHz component signal, and the signal that passed through the filter that allows only the 50 MHz component signal to pass simultaneously is measured as the measurement result of the 50 MHz component signal. can do.

  Next, at the time of the 50th turn, the interdigital electrode 2a is again brought close to the surface of the piezoelectric crystal sphere (quartz) for a short time (about the time corresponding to one turn), and 150 MHz is passed through a filter that passes a frequency component of 150 MHz. The intensity and phase of the surface acoustic wave of the frequency component of the above are measured and the interdigital electrode 2a is separated again. Next, the interdigital electrode 2a is again brought close to the surface of the piezoelectric crystal sphere (quartz crystal) in order to measure the 150th round signal of the surface acoustic wave by the frequency component of 50 MHz, and only the frequency component of 50 MHz of the output at that time is obtained. And the intensity and phase of the surface acoustic wave may be measured. This measurement method has the advantage of being able to measure at high speed because it can simultaneously circulate surface acoustic waves with a plurality of frequencies.

  In the device of the present invention, the double finger electrode is used to excite the surface acoustic wave 12 of a plurality of frequency bands. For example, as shown in FIG. 6, the interdigital electrode 2b for exciting and detecting the surface acoustic wave 12 of 50 MHz. Also, the interdigital electrode 2c for exciting and detecting the surface acoustic wave 12 of 150 MHz can be formed side by side.

(Second Embodiment)
FIG. 7 is a block diagram showing a second embodiment of the spherical surface acoustic wave device according to the present invention. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals, and redundant description thereof is omitted. Hereinafter, different portions will be described.

  In this spherical surface acoustic wave device, a plurality of relative distance adjusting means 3 ′, 3 ″ having substantially the same configuration as the relative distance adjusting means 3 used in the first embodiment is used. Two relative distance adjusting means 3 ′ and 3 ″ are arranged so as to face each other at an angle of 90 degrees with respect to the circulation path 11 of the wave element 1.

  The relative distance adjusting means 3 ′ and 3 ″ are connected to each other in the order of the fixing member 36, the four-direction position adjusting stage 32, the two-way position fine adjusting stage 37, and the minute relative distance adjusting means 33, respectively. A support 21 for forming the surface acoustic wave excitation / detection means 2 ′, 2 ″ is attached to the tip of the distance adjustment means 33, respectively.

  As the surface acoustic wave excitation / detection means 2 ′, an interdigital electrode 2b as shown in FIG. 6 is formed, and its center frequency is 50 MHz. As the other surface acoustic wave excitation / detection means 2 ″, an interdigital electrode 2c as shown in FIG. 6 is formed, and its center frequency is 150 MHz. That is, two different frequencies, 50 MHz and 150 MHz, are used. Each interdigital electrode 2b, 2c approaches the piezoelectric crystal sphere at an independent timing to excite and detect the surface acoustic wave 12.

  Thus, the advantage of approaching and separating the interdigital electrodes 2b and 2c for each frequency is that when the interdigital electrodes 2b and 2c having a plurality of frequency bands are used, the interdigital electrodes 2c are spherical. When excitation of a frequency component of 150 MHz is performed in the vicinity of the surface acoustic wave element 1, the interdigital electrode 2b having a frequency of 50 MHz does not approach the spherical surface acoustic wave element 1 at the same time. Even though the interdigital electrodes 2b and 2c are not in contact with the piezoelectric crystal sphere, the interdigital transducers 2b and 2c affect the propagation of the surface acoustic wave 12 during circulation due to electrical interaction. In particular, the surface acoustic wave component of 50 MHz and the frequency component of 150 MHz are affected by the surface acoustic wave 12 having a low frequency component when detecting a high frequency component because the frequency of detection and measurement is different as described above. It is desirable to avoid this.

  In the example of the present embodiment, the 50 MHz interdigital electrode 2b and the 150 MHz interdigital electrode 2c can be excited and detected while being moved independently. For example, when detecting a surface acoustic wave 12 having a 150 MHz frequency, Even if the interdigital electrode 2c is approached, it is possible to avoid affecting the interdigital electrode 2c.

  In this embodiment, although not shown, a burst signal generator that generates high-frequency burst signals with frequencies of 50 MHz and 150 MHz, an amplifier that detects and amplifies the signal of the surface acoustic wave 12 based on excitation of the frequency, and a signal The processing means can be made separately or independently, or a single device can play both roles.

  In the present embodiment, as shown in FIG. 7, the plurality of surface acoustic wave excitation / detection means 2 ′ and 2 ″ are arranged so as to be orthogonal to each other, but each surface acoustic wave excitation has an angle of 120 degrees. -A detection means can also be arranged.

  In addition, the present invention is not limited to the above-described embodiments and examples, and various modifications can be made without departing from the scope of the invention.

  DESCRIPTION OF SYMBOLS 1 ... Spherical surface acoustic wave element 2, 2 ', 2 "... Surface acoustic wave excitation and detection means, 2a, 2b, 2c ... Interdigital electrode, 3 ... Relative distance adjustment means, 4 ... Control processing system, 11 ... Circulation Path: 12 Surface acoustic wave, 13: Support base, 21: Support, 31: Coarse relative distance adjustment stage, 32: Four-direction position adjustment stage, 33: Minute relative distance adjustment means, 36: Fixing member, 37 ... Two-direction position fine adjustment stage, 41... Central controller, 42... High frequency burst signal generator, 43 ... circulator, 44 ... amplifier, 45 ... digitizer, 46.

Claims (4)

A spherical surface acoustic wave element in which a circular path is formed on at least a part of the outer surface of the spherical shape and the surface acoustic wave propagates along the circular path when excited by a high frequency burst signal;
High-frequency burst signal generating means for generating a plurality of high-frequency burst signals of different frequencies:
Two relative distance adjusting means arranged at a predetermined angle with each other along the circular path of the spherical surface acoustic wave element and opposed to the circular path ;
Interdigital electrodes of two surface acoustic wave excitation / detection means supported by the two relative distance adjustment means so as to be relatively movable facing the circular path of the spherical surface acoustic wave element;
The two relative distance adjusting means are instructed to move the two surface acoustic wave excitation / detecting means with respect to the circular path of the spherical surface acoustic wave element, and one of the two relative distance adjusting means is provided. A surface acoustic wave is applied to the circular path of the spherical surface acoustic wave element by a comb electrode of one of the surface acoustic wave excitation / detection means supported by a selected one of the plurality of high frequency burst signals having different frequencies. The relative distance adjustment of the one when excited and continuously propagated along the circuit path and when a signal generated from a surface acoustic wave that has circulated the circuit path a predetermined number of times is detected and output as a received signal The interdigital electrode of the one surface acoustic wave excitation / detection means is brought close to the circular path by means of the interdigital electrode of the one surface acoustic wave excitation / detection means. Serial the one of the surface acoustic wave excitation and the surface acoustic waves the orbiting interdigital transducer away from the circular path of the sensing means electromagnetic influences the surface acoustic wave in the circumferential path after starting the circulation by pumping Selected from the plurality of high frequency burst signals of different frequencies by the interdigital electrode of the other surface acoustic wave excitation / detection means supported on the other of the two relative distance adjustment means. When another surface acoustic wave is excited in the circular path of the spherical surface acoustic wave element and continuously propagated along the circular path and circulated, and from the surface acoustic wave that has circulated the circular path a predetermined number of times When the generated signal is detected and output as a reception signal, the other surface-wave excitation / detection means of the interdigital electrode of the other surface acoustic wave excitation / detection means is performed by the other relative distance adjustment means. Is near, interdigital electrodes of the other surface acoustic wave excitation and detection means after the to initiate circulates a surface acoustic wave is excited in the circular path at interdigital electrodes of the other surface acoustic wave excitation and detection means The surface acoustic wave that circulates away from the circuit path is not affected electromagnetically,
Furthermore, the approach of the interdigital electrode of the one surface acoustic wave excitation / detection means by the one relative distance adjusting means with respect to the circular path and the other surface acoustic wave by the other relative distance adjusting means with respect to the circular path. Performing the approach of the interdigital electrode of the excitation / detection means at a different time,
Desirable from change in propagation characteristics of the surface acoustic wave due to a difference in frequency between the signal detected by the one surface acoustic wave excitation / detection means and the signal detected by the other surface acoustic wave excitation / detection means A control processing system that measures environmental changes;
A spherical surface acoustic wave device comprising: The distance of the interdigital electrode of the surface acoustic wave excitation / detection means to the circular path is up to a distance of 1/4 or less of the wavelength on the circular path of the surface acoustic wave at the highest frequency among the plurality of frequencies. Bring the interdigital electrode closer to the circuit path,
Further, the distance of the interdigital electrode of the surface acoustic wave excitation / detection means from the circular path is a distance of 1/4 or more of the wavelength on the circular path of the surface acoustic wave at the lowest frequency among the plurality of frequencies. Moving the interdigital electrode away from the circuit path;
The spherical surface acoustic wave device according to claim 1. The relative distance adjusting means moves the surface acoustic wave excitation / detection means in a direction intersecting an annular extending direction of the circular path or along a radial direction of at least a part of the spherical shape with respect to the circular path. It was moved in the direction, that the spherical elastic sheet surface wave device according to claim 1 or 2, characterized in. The relative distance adjusting means includes a deformation material when subjected to a predetermined voltage signal, that the spherical elastic sheet surface wave device according to any one of claims 1 to 3, characterized in.

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