CN1135692C - Piezo-resonator, and filter and AM receiving circuitry using the same resonator - Google Patents
Piezo-resonator, and filter and AM receiving circuitry using the same resonator Download PDFInfo
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- CN1135692C CN1135692C CNB971026580A CN97102658A CN1135692C CN 1135692 C CN1135692 C CN 1135692C CN B971026580 A CNB971026580 A CN B971026580A CN 97102658 A CN97102658 A CN 97102658A CN 1135692 C CN1135692 C CN 1135692C
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- 239000000758 substrate Substances 0.000 claims abstract description 112
- 230000002093 peripheral effect Effects 0.000 claims description 52
- 238000002156 mixing Methods 0.000 claims description 6
- 230000035939 shock Effects 0.000 abstract 1
- 238000000034 method Methods 0.000 description 9
- 239000002184 metal Substances 0.000 description 7
- 238000005452 bending Methods 0.000 description 5
- 230000004888 barrier function Effects 0.000 description 3
- 238000001514 detection method Methods 0.000 description 3
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- 230000010287 polarization Effects 0.000 description 3
- 230000006835 compression Effects 0.000 description 2
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- 238000000354 decomposition reaction Methods 0.000 description 2
- 238000003754 machining Methods 0.000 description 2
- GOLXNESZZPUPJE-UHFFFAOYSA-N spiromesifen Chemical compound CC1=CC(C)=CC(C)=C1C(C(O1)=O)=C(OC(=O)CC(C)(C)C)C11CCCC1 GOLXNESZZPUPJE-UHFFFAOYSA-N 0.000 description 2
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/02—Details
- H03H9/05—Holders; Supports
- H03H9/10—Mounting in enclosures
- H03H9/1007—Mounting in enclosures for bulk acoustic wave [BAW] devices
- H03H9/1014—Mounting in enclosures for bulk acoustic wave [BAW] devices the enclosure being defined by a frame built on a substrate and a cap, the frame having no mechanical contact with the BAW device
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/56—Monolithic crystal filters
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/56—Monolithic crystal filters
- H03H9/566—Electric coupling means therefor
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- H—ELECTRICITY
- H03—ELECTRONIC CIRCUITRY
- H03H—IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
- H03H9/00—Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
- H03H9/46—Filters
- H03H9/54—Filters comprising resonators of piezoelectric or electrostrictive material
- H03H9/58—Multiple crystal filters
- H03H9/60—Electric coupling means therefor
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Abstract
The resonator formed on a rectangular flat piezoelectric substrate (12) has a front electrode divided into three sections (14a-14c), and an undivided back earthing electrode (16). The divisions (18,20) are parallel to and equidistant from the longitudinal axis. The sections extend throughout the length of the substrate, and the aggregate width of the two outer sections is substantially equal to the width of the central section. Input/output connections (22,24) are made to the two outer sections and the central section respectively of the front electrode. The device is used in at least the final stage of a multi-resonator filter.To obtain the piezoelectric resonator which can have unnecessary signal output suppressed even when a mechanical shock is applied, the filter which uses it, and the AM receiving circuit. The piezoelectric resonator 10 includes a rectangular plate type piezoelectric substrate 12 and has electrodes 14 and 16 formed on both its surfaces. The electrode 14 is divided into three along the width by grooves 18 and 20 extending along the length of the piezoelectric body substrate 12. The grooves 18 and 20 are formed symmetrically about a center line along the length of the piezoelectric body substrate 12. Outside parts 14a and 14c of the divided electrode 14 are used as one input/output terminal 22 and the center part 14 is used as the other input/output terminal 24. When a filter is formed by connecting plural piezoelectric resonators, this piezoelectric resonator 10 is used at least in the final stage. Those piezoelectric resonator 10 and filter are used as the intermediate frequency filter of the AM receiving circuit.
Description
The present invention relates generally to a kind of piezo-electric resonator and the filter that uses this resonator.The invention particularly relates to a kind of piezo-electric resonator that uses in intermediate-frequency filter, this intermediate-frequency filter can use in for example amplitude modulation (AM) broadcast receiver.The invention still further relates to a kind of filter and AM receiving circuit that uses above-mentioned resonator.
Referring to the perspective view of Figure 27, it shows an example of known piezo-electric resonator type, generally represents piezo-electric resonator with 1, and it comprises the flat piezoelectric substrate 2 of making rectangle.On the positive and negative surface of piezoelectric substrate 2, form electrode 3 and 4.Electrode 3 is divided into two electrode part 3a and 3b along the width across the substrate 2 of groove 5, and divided portion 3a and 3b are used separately as I/O end 6a and 6b.Another electrode 4 is as grounding electrode.
In this piezo-electric resonator 1, can be used as the longitudinal vibration mode that the I/O electrode comes the applying piezoelectric device to these two electrode part 3a and 3b.Figure 28 and 29 shows the frequency characteristic of piezo-electric resonator 1.Figure 29 has partly amplified Figure 28, and the resonance frequency and the characteristic of frequency on every side thereof have been described.As can be seen, use the piezo-electric resonator of longitudinal vibration mode can make littler than the piezo-electric resonator of square vibration mode.
The piezo-electric resonator of longitudinal vibration mode for example can be used to be applied in the wireless intermediate-frequency filter of AM.In the AM receiving circuit, the signal of local-oscillator circuit output carries out mixing in signal that receives and the mixting circuit.The output signal of mixting circuit is taken out intermediate-freuqncy signal by intermediate-frequency filter.Intermediate-freuqncy signal is amplified in intermediate frequency amplifier circuit then, carries out detection again in detecting circuit.Then, the signal that detection obtains amplifies in low-frequency amplifier circuit, and the output amplifying signal drives loud speaker.
Yet as shown in figure 30, the external impact power that acts on the broadcast receiver has caused bending to piezo-electric resonator.Since this bending, one side expansion of piezoelectric substrate, and another side shrinks, thereby, the opposite electric charge of polarization on substrate.These electric charges are exported from the I/O end unfriendly as signal, and it also sends receiver amplifier to, and finally drive loud speaker, produce noise.
Therefore, a main purpose of the present invention is to provide a kind of piezo-electric resonator, it can in addition still can prevent to export undesired signal when mechanical impact is arranged, a kind of filter and AM receiving circuitry that uses such piezo-electric resonator also is provided.
To achieve these goals, according to an aspect of the present invention, the piezo-electric resonator that provides comprises: the flat piezoelectric substrate of making rectangle; And be formed on two lip-deep two electrodes of piezoelectric substrate, at least an electrode is divided at least three parts along the width of piezoelectric substrate, two peripheral electrode parts of electrode separately are mutually symmetrical with respect to the center line along the piezoelectric substrate longitudinal extension, wherein, respectively as I/O end and earth terminal, at least two peripheral electrodes of the described electrode that separates partly connect into as one of I/O end with the electrode that separates and another electrode.
In above-mentioned piezo-electric resonator, at least one electrode can be cut apart by this way, promptly three divided portion can be parallel with the center line along the longitudinal extension of piezoelectric substrate, and the overall width of peripheral electrode part is substantially equal to the width of contre electrode part separately.
On the other hand, can cut apart at least one electrode by this way, promptly three divided portion can be parallel with the center line along the longitudinal extension of piezoelectric substrate, and the width of each peripheral electrode part equates with the width of the contre electrode part of separating basically.
In addition, can be fixed to the conduction supporter on the electrode separately on the site position of piezoelectric substrate, can be connected to the electrode that separates on the pattern electrodes that is formed on the insulating substrate with supporter.
According to a further aspect in the invention, a kind of filter that provides comprises the piezo-electric resonator that a plurality of and described filter links to each other, and wherein, uses the resonator of the above-mentioned type at least in the final stage of a plurality of piezo-electric resonators.
According to a further aspect of the invention, a kind of AM receiving circuit that provides comprises: the mixting circuit that the signal of signal that receives and local-oscillator circuit is carried out mixing; From the output signal of mixting circuit, take out the intermediate-frequency filter of intermediate-freuqncy signal; And the detecting circuit that from the intermediate-freuqncy signal that obtains by intermediate-frequency filter, detects voice signal, wherein above-mentioned piezo-electric resonator or filter are used as intermediate-frequency filter.
In above-mentioned piezo-electric resonator, two peripheral parts of the electrode that separates are connected to each other to as an I/O end, and middle body is used as another I/O end.Can substrate transversely electrode is divided at least three parts, thereby on substrate, produce extensional vibration.Can obtain to use the filter characteristic of this longitudinal vibration mode.
If the exterior mechanical effect of impact is arranged in this piezo-electric resonator, substrate can produce bending.So further partly distinguish the opposite electric charge of polarization, also at the opposite electric charge of contre electrode part polarization at two peripheral electrodes.Therefore, can eliminate electric charge to the interconnection each other of peripheral electrode part.And, also can offset the opposite polarity electric charge that middle body produces.In addition, the suitable method of attachment of selection can be eliminated the opposite polarity electric charge in other parts generations of the electrode that separates.
Especially, can be divided into three parts and parallel with the center line of substrate extension longitudinally at least one electrode, the overall width of peripheral electrode part can be made basically and equate with the width of contre electrode part.For this structure, the area of the peripheral part of connection can equate with the area of middle body.And, can be used as two I/O ends to peripheral part that separates and middle body, can be used as earth terminal to the electrode that is arranged on the substrate opposite face.Therefore, the electric capacity between I/O end and the earth terminal can equal the electric capacity between another I/O end and the earth terminal.Between the overall width of peripheral part and middle body width, used term " to equate substantially ", according to when small pieces are carried out micromachined to desired value have+-20% and the machining accuracy error obtain.
On the other hand, can cut apart at least one electrode by this way, three parts of promptly separating can be parallel with the center line of substrate extension longitudinally, and the width of each peripheral part is substantially equal to the width of middle body.Can avoid occurring the minimum part of width like this.Therefore, can prevent from substrate is cut into pieces, when small pieces are carried out micromachined, can avoid electrode to come off.Between the width of the peripheral electrode that respectively separates part and middle body width, used term " to equate substantially ", be basis when small pieces are carried out micromachined to desired value have+-20% machining accuracy error obtains.
And, providing the conduction supporter to be attached to piezo-electric resonator on the piezoelectric substrate that has pattern electrodes on it on the electrode that separates.By means of this supporter, the node and the substrate of resonator part rather than substrate are separated, otherwise it will limit the vibration of substrate.
In the filter that adopts a plurality of piezo-electric resonators, piezo-electric resonator of the present invention is applicable to the final stage of a plurality of resonators at least.Therefore, can stop first order resonator because the noise that external impact produces is exported from filter, this is because the signal frequency of first order resonator is different with the resonance frequency of final stage resonator.
Above-mentioned piezo-electric resonator or filter can be used in the intermediate-frequency filter that the AM receiving circuit uses.Therefore can prevent because the output of the noise that external impact produces can improve the response of looking genuine, thereby eliminate the undesired signal of telecommunication.
As can being expressly understood, the invention provides following all advantages from foregoing description.
Even the exterior mechanical bump is arranged, still can offset the electric charge of generation, thereby forbid exporting undesired signal.Especially when being divided into three parts to electrode, when the overall width of peripheral part equaled the width of middle body substantially, the electric capacity between I/O end and the earth terminal can equate with electric capacity between the earth terminal with another I/O end.Therefore, can be any of two I/O ends as input or as output, the resonator characteristics that obtains is identical.On the other hand, can be divided into three parts to electrode, the width of each peripheral part is made the width that is substantially equal to middle body.This can eliminate the minimum part of width, thereby prevents to damage when carrying out micromachined resonator.In this mode, make this piezo-electric resonator easily.And if piezo-electric resonator is attached on the substrate that has pattern electrodes on it with supporter, then piezo-electric resonator can freely vibrate, thereby obtains good characteristic.
And, in the filter that adopts a plurality of piezo-electric resonators, can be the final stage of piezo-electric resonator of the present invention as a plurality of resonators.Therefore, can avoid the interior any noise that produces of resonator of the first order from filter, to export.And above-mentioned piezo-electric resonator or filter can be used for the intermediate-frequency filter of AM broadcast receiver, thereby reduce wide
The response of looking genuine.Therefore can block the undesired signal of telecommunication of output, reduce the noise of loud speaker.
Above-mentioned purpose of the present invention, other purpose, feature and advantage are according to below in conjunction with accompanying drawing the description of embodiment being become more obvious.
Fig. 1 is the perspective view of piezo-electric resonator according to an embodiment of the invention;
Fig. 2 is to use the perspective view of three end piezoelectric parts of piezo-electric resonator shown in Figure 1;
Fig. 3 is the decomposition diagram of piezoelectric part shown in Figure 2;
Fig. 4 is the perspective view of the piezo-electric resonator of use in the piezoelectric part shown in Figure 2;
Fig. 5 shows as external impact and makes time spent piezo-electric resonator shown in Figure 1;
Fig. 6 is the end view of the improvement example of piezo-electric resonator shown in Figure 1;
Fig. 7 is the frequency characteristic figure of piezo-electric resonator shown in Figure 1;
Fig. 8 is according to resonance frequency and the on every side performance plot of frequency part thereof of performance plot shown in Figure 7 through amplifying;
Fig. 9 is the frequency characteristic figure of piezo-electric resonator shown in Figure 6;
Figure 10 is according to resonance frequency and the on every side performance plot of frequency part thereof of performance plot shown in Figure 9 through amplifying;
Figure 11 is the perspective view that uses the filter of two piezo-electric resonators shown in Figure 1 according to one embodiment of the invention;
Figure 12 is the decomposition diagram that uses the filter of two piezo-electric resonators shown in Figure 1 according to a further embodiment of the invention;
Figure 13 is the perspective view that uses the filter of piezo-electric resonator shown in Figure 1 in final stage;
Figure 14 shows in the first order and uses piezo-electric resonator shown in Figure 6, uses the filter of piezo-electric resonator shown in Figure 1 in final stage;
Figure 15 is the frequency characteristic figure of filter shown in Figure 11;
Figure 16 is according to the frequency of the performance plot of Figure 15 resonance frequency through amplifying and the performance plot of frequency on every side thereof;
Figure 17 is the frequency characteristic figure of filter shown in Figure 13;
Figure 18 is according to the performance plot of Figure 17 resonance frequency and the performance plot of frequency on every side thereof through amplifying;
Figure 19 is the frequency characteristic figure of filter shown in Figure 14;
Figure 20 is according to the performance plot of Figure 19 resonance frequency and the performance plot of frequency on every side thereof through amplifying;
Figure 21 is to use the frequency characteristic figure of the filter of the two conventional piezoelectric resonators that interconnect;
Figure 22 is according to the performance plot of Figure 21 resonance frequency and the performance plot of frequency on every side thereof through amplifying;
Figure 23 is the block diagram of AM receiving circuit, in this receiving circuit piezo-electric resonator of the present invention or filter is used as intermediate-frequency filter;
Figure 24 has four perspective views of cutting apart the piezo-electric resonator of electrode part;
Figure 25 has five perspective views of cutting apart the piezo-electric resonator of electrode part;
Figure 26 is the perspective view to the used improvement method of attachment of piezo-electric resonator shown in Figure 25;
Figure 27 is the perspective view of the piezo-electric resonator of a routine known type;
Figure 28 is the frequency characteristic figure of conventional piezoelectric resonator shown in Figure 27;
Figure 29 is according to the performance plot of Figure 28 resonance frequency and the performance plot of frequency on every side thereof through amplifying;
Figure 30 illustrates as external impact and makes time spent piezo-electric resonator shown in Figure 27.
Referring to Fig. 1, piezo-electric resonator represents with 10 that generally it comprises the flat piezoelectric substrate 12 of making rectangle.Tow sides at substrate 12 are respectively arranged with electrode 14 and 16.Be formed with two grooves 18 and 20 on an electrode 14, their substrates 12 longitudinally extend. Groove 18 and 20 is made symmetrical mutually with respect to the central shaft of vertical substrate 12, especially in this resonator 10, groove 18 and 20 is made the central shaft that is parallel to vertical substrate 12.These grooves 18 and 20 are set are divided into three electrode part 14a, 14b and 14c to electrode 14.Should be noted that groove 18 and 20 is not to be parallel to central shaft, as long as they are mutually symmetrical with respect to this axle.That is only be that electrode part 14a on electrode 14 peripheries and 14c form that to be mutually symmetrical with respect to center line be necessary.
In this resonator 10, electrode 16 plays the effect of earth terminal.And, in the present embodiment, two I/ O ends 22 and 24 are arranged: electrode part 14a on electrode 14 peripheries and 14c are connected to each other to as an I/O end 22, and the electrode part 14b of electrode 14 centre is used as another I/O end 24.For this structure, a signal is input to an I/O end 22, on substrate 12, produce extensional vibration, from the consequential signal of another I/O end 24 outputs corresponding to resonance frequency.
Shown in Fig. 2 and 3, above-mentioned piezo-electric resonator 10 can use in three end piezoelectric parts.Piezoelectric part represents that with 30 it has an insulating substrate 32.Form two pattern electrodes 34 and 36 from vertical substrate 32 two ends to central authorities on the first surface of substrate 32, electrode 34 and 36 toward each other.Also electrode 34 and 36 is arranged to extend to second surface from the side of substrate 32, two I/ O lead ends 38 and 40 are connected respectively to pattern electrodes 34 and 36.
On the first surface of insulating substrate 32, except the gap between relative pattern electrodes 34 and 36 forms insulating barrier 42.Then piezo-electric resonator 10 is installed on electrode 34 and 36 by supporter 44.As shown in Figure 4, supporter 44 is made up of three parts 46,48 and 50, and these three parts are attached to respectively on electrode part 14a, 14b and the 14c in the center of vertical substrate 12.Support that part 46 and 50 is fixed on peripheral electrode part 14a and the 14c, near first end of vertical substrate 12, it has current-carrying part 46b and 50a, has insulated part 46b and 50b near second end of substrate 12.On the contrary, support that part 48 is attached on the contre electrode part 14b, have a current-carrying part 48a, near first end, have insulated part 48b at the second end place near vertical substrate 12.Therefore, peripheral electrode part 14a and 14c and contre electrode part 14b are in the vertical conducting with substrate 12 of the different piece of supporter 44.
Utilize the supporter 44 of said structure, peripheral electrode part 14a and 14c are electrically connected on the pattern electrodes 34, and contre electrode part 14b is electrically connected on another pattern electrodes 36.Therefore, electrode part 14a and 14c are electrically connected on the I/O lead end 38, and electrode part 14b is electrically connected on another I/O lead end 40.
And lead-in wire 52 is connected to the middle body of electrode 16, and metal cap 54 covers on piezo-electric resonator 10.Therefore, can be bonded to each other lead-in wire 52 and metal cap 54 with conducting resinl 56.Moreover, ground lead end 58 is connected on the metal cap 54, be electrically connected thereby between the electrode 16 of resonator 10 and ground lead end 58, set up.Insulating barrier 42 a pattern electrodes 34 and 36 and metal cap 54 electric insulations are set.Then shell 60 is covered insulating substrate 32 and metal cap 54 outsides.Can produce piezoelectric part 30 by this way.
In above-mentioned piezoelectric part 30, the middle body of resonator 10 is supported by supporter 44 as node, otherwise can stop the extensional vibration of piezoelectric substrate 12, thereby obtains good characteristic.As shown in Figure 4, form two grooves 62 in resonator 10, it extends along the width of substrate 12, and is positioned at from the sixth of the length of the whole substrate 12 of the inward at both ends of vertical substrate 12.It is in order to prevent to produce the trivalent high order harmonic component that these grooves 62 are set.
If external impact acts on this resonator 10, on substrate 12, may produce bending as shown in Figure 5, the center line expansion substrate 12 that it extends with respect to substrate longitudinally 12 unfriendly a side, the compression opposite side.This can produce positive charge at the expansion of substrate 12, and produces negative electrical charge at compression section.Yet, because external electrode part 14a and 14c are connected to each other, so can eliminate these positive charges and negative electrical charge.And, at contre electrode part 14b, can offset at the opposite polarity electric charge that each side of the center line of substrate 12 produces, otherwise the undesired output that I/ O end 22 or 24 output external impact are produced.
On the other hand, as shown in Figure 6, can be divided into three electrode part 14a, 14b, 14c and 16a, 16b, 16c respectively being arranged on substrate 12 double-edged electrodes 14 and 16.In this case, the contre electrode part 14b of electrode 14 can be used as an I/O end 22, and peripheral electrode part 14a and 14c can be connected on the contre electrode part 16b and be used for ground connection.And, can be coupled peripheral electrode part 16a and 16c each other, as another I/O end 24.In this resonator 10 and resonator shown in Figure 1, because substrate 12 bendings can be offset at peripheral electrode part 14a and 14c and the electric charge that produces in contre electrode part 14b.Equally, also can offset at peripheral electrode part 16a and 16c and the electric charge that in contre electrode part 16b, produces.This can prevent that I/ O end 22 or 24 outputs are because the undesired signal that external impact causes.
In the piezo-electric resonator 10 of structure as mentioned above, can reduce because the undesired signal that external impact produces.Therefore, this resonator 10 is applied to the wireless intermediate-frequency filter of AM, can reduces because the noise output that external impact produces loud speaker.In addition, Fig. 7,8,9 and 10 illustrates, and in the resonant frequency range of the resonator 10 of the above-mentioned type, attenuation amplitude is substantially equal to traditional piezo-electric resonator, can obtain the less response of looking genuine in resonator 10.Fig. 7 and Fig. 8 show the characteristic of piezo-electric resonator shown in Figure 1 10, and Fig. 9 and Figure 10 show the characteristic of resonator shown in Figure 6 10.Fig. 8 and 10 illustrates in greater detail respectively according to the performance plot of Fig. 6 and Fig. 9 resonance frequency and the characteristic of frequency on every side thereof through amplifying.
In the following manner above-mentioned piezo-electric resonator 10 has been carried out the assessment test.Apply the vibration of 10G (greatly to acceleration of gravity 10 times) 1kHz with three directions (coordinate as shown in Figure 1 promptly is defined as directions X to Width, and longitudinal direction is defined as the Y direction, and thickness direction is defined as the Z direction) of resonator 10.The consequential signal that measurement is exported between output and grounding electrode.Its result is as shown in table 1.
Table 1
| Output voltage (mV) | |||
| Piezo-electric resonator | The directions X vibration | The vibration of Y direction | The vibration of Z direction |
| The present invention | 0.7 | 0.0 | 0.3 |
| Traditional type | 10.2 | 0.9 | 1.5 |
Table 1 demonstration piezo-electric resonator 10 of the present invention is compared with the resonator of known type and can be realized reducing noise.Especially only in resonator 10, cause the atomic little noise of 0.7mV in the vibration that applies on the directions X, on the contrary, in traditional resonator, then produce the noise of 10.2mV.In this mode,, can realize the low noise piezo-electric resonator 10 of impact resistance according to the present invention.
In piezo-electric resonator shown in Figure 1 10, if the overall width of peripheral electrode part 14a and 14c is made the width that equals contre electrode part 14b, then the former gross area can equal the latter's area.As mentioned above, peripheral part 14a and 14c are interconnected with one another, with as an I/O end 22, and middle body 14b are used as another I/O end 24.Therefore, the electric capacity between I/O end 22 and the electrode 16 can equate with electric capacity between the electrode 16 with I/O end 24.This can guarantee in I/O end 22 or 24 any one as input or output, and resonator 10 can obtain identical characteristic.Therefore, when resonator 10 is applied to piezoelectric part 30 for example shown in Figure 2, needn't determine I/O lead end 38 or 40 which as input or output.
On the other hand, can make the width of each peripheral electrode part 14a and 14c basically and equate, thereby eliminate the minimum part of width with the width of contre electrode part 14b.This can prevent that the piezoelectric substrate 12 from cutting into pieces, and can avoid that electrode 14 comes off when small pieces are carried out micromachined.Therefore, can make piezo-electric resonator 10 easily, and protect man-hour piezo-electric resonator to avoid being damaged adding.
As shown in figure 11, for further exploitation the present invention, use two resonators 10 can produce filter.Filter generally represents that with 70 it comprises for example insulating substrate 72.Be arranged on the insulating substrate 72 is tablet pattern electrode 74, output pattern electrode 76 and ground connection pattern electrodes 78.Input and output pattern electrodes 74 and 76 is built in parallel to each other near the both sides of substrate 72.Ground connection pattern electrodes 78 is arranged to be between input and output pattern electrodes 74 and 76.All electrodes 74,76 and 78 are made from the relative side of a side direction of substrate 72 and are extended.And, the outer end 82 that is used for being connected with external circuit is arranged on the side of substrate 72, respectively above-mentioned electrode 74,76 and 78 is connected on these terminals 82.
Two piezo-electric resonators 10 are placed on the ground connection pattern electrodes 78, and the electrode 16 of resonator 10 is by bonding on the ground connection pattern electrodes 78 such as conducting resinl 84.And the peripheral electrode part 14a of a resonator 10 and 14c are connected on the tablet pattern electrode 74 with lead-in wire, and the peripheral electrode part 14a of another resonator 10 and 14c are connected on the output pattern electrode 76 with lead-in wire.Moreover the contre electrode part 14b of each resonator 10 is coupled each other with a lead-in wire.Then a metal cap 86 is covered on resonator 10.
In filter 70, and in single resonance device 10, can forbid exporting because the undesired signal that external impact produces to resonator 10 roles by being similar to above-mentioned resonator of two-stage 10.
On the other hand, can use supporter 44 as shown in Figure 4, can be installed to piezo-electric resonator 10 on the insulating substrate 72 like this.In this case, as shown in figure 12, the input and output pattern electrodes 74 of formation and 76 extends to central authorities from the both sides of substrate 72.And public electrode 88 is arranged to respect to input and output pattern electrodes 74 and 76.Form ground connection pattern electrodes 78 from one side of substrate 72 to its relative one side.
Then, a piezo-electric resonator 10 is installed between tablet pattern electrode 74 and the public electrode 88 by supporter 44, and another piezo-electric resonator 10 is fixed between output pattern electrode 76 and the public electrode 88 by another supporter 44.This can also can be connected to the peripheral electrode part 14a of resonator 10 and 14c on input and output pattern electrodes 74 and 76 by public electrode 88 respectively the contre electrode part 14b of two resonators 10.And, with lead-in wire the electrode 16 of each resonator 10 is connected on the ground connection pattern electrodes 78.Then metal cap 86 being striden across insulating barrier 90 covers on substrate 72.In above-mentioned filter 70, can support with supporter 44 as the middle body of the resonator 10 of node, and the other parts of resonator 10 and substrate 72 separate, otherwise will influence the extensional vibration of resonator 10, thereby realize good characteristic.
As shown in figure 13, above-mentioned filter 70 can also improve, and can be used in the first order to conventional piezoelectric resonator 1, and resonator 10 of the present invention only is used for final stage.In such filter 70, even 1 output of the resonator of the first order is because the undesired signal that external impact produces, but it still can prevent 76 outputs of output pattern electrode, and this is because the resonance frequency of sort signal is different with the resonance frequency of the resonator 10 of final stage.Therefore, use piezo-electric resonator 10 of the present invention can realize a kind of like this filter,, still can avoid exporting undesired signal even external impact is arranged.
On the other hand, as shown in figure 14, can also following manner improve filter 70.Can be used in the first order to the piezo-electric resonator 10 that on the tow sides of substrate 12, has electrode part separately, and the resonator 10 that only has electrode part separately on a surface of substrate 12 is used in final stage.At such filter 70 and in above-mentioned filter,, export undesired signal thereby stop because the electric charge that external impact produces can be offset.Should be noted that two class resonators 10 shown in Figure 14 can exchange simply between the first order and final stage.
For the characteristic of more above-mentioned filter 70, measure its frequency characteristic.Figure 15 and 16 illustrates the frequency characteristic of the above-mentioned filter 70 of the resonator 10 that is provided with two interconnection.Figure 17 and 18 shows at input and uses resonator 1, uses the frequency characteristic of the filter 70 of resonator 10 of the present invention at output.And, Figure 19 and 20 shows the resonator 10 that all has electrode part separately at the tow sides of substrate is used in input, and only have on a surface of substrate electrode separately partly resonator 10 be used in the frequency characteristic of the filter 70 of output.In addition, Figure 21 and 22 shows the characteristic of the filter of the interconnection resonator that uses two kinds of traditional types.These figure show that the characteristic of each filter is suitable basically.
Vibration is put on above-mentioned filter to assess.Use the maximum of signal of the filter output of two traditional resonator to be 10.2mV, and use the signal maximum of the filter output of a resonator 10 of the present invention only to be 0.7mV at least.This tests demonstration, can realize the filter of anti-external impact with piezo-electric resonator of the present invention.
In fact, as shown in figure 14, use all to have electrode 14 separately and 16 piezo-electric resonator 10 on two surfaces, produce attenuation pole in resonance frequency both sides shown in Figure 20, thereby obtain desirable filtering characteristic.
In order further to develop the present invention, as shown in figure 23, can be applied to the AM receiving circuit to above-mentioned piezo-electric resonator 10 or filter 70.AM receiving circuit 100 has an antenna 102.Antenna 102 is connected to mixting circuit 104, and further is connected to local-oscillator circuit 106.In mixting circuit 104, the signal that receives with carry out mixing from the signal of local-oscillator circuit 106.Mixting circuit 104 is couple on the intermediate-frequency filter 108.Intermediate-frequency filter 108 is connected to intermediate frequency amplifier circuit 110, and it further is coupled to detecting circuit 112.Detecting circuit 112 is connected to low-frequency amplifier circuit 114, and the latter's output signal drives loud speaker 116.Can be used in above-mentioned piezo-electric resonator 10 or filter 70 in the intermediate-frequency filter 108 of AM receiving circuit 100.
As mentioned above, in mixting circuit 104, the signal of signal that receives and local-oscillator circuit 106 is carried out mixing, produce an intermediate-freuqncy signal, its frequency is the difference between the signal that these machines produce in the signal that receives and the local-oscillator circuit 106.Only take out intermediate-freuqncy signal by intermediate-frequency filter 108 then.In Japan, the frequency of this signal is decided to be 455kHz.The intermediate-freuqncy signal that contains the modulation signal of the radio wave that main expression receives can be carried out detection with detecting circuit 112, takes out modulation signal.From detecting circuit 112 output low frequency restituted signals, in low-frequency amplifier circuit 114, amplify then.Output signal by circuit 114 drives loud speaker 116, makes its sounding.
In the intermediate-frequency filter 108 of the as above AM receiving circuit 100 of structure, piezo-electric resonator 10 of the present invention or filter 70 can be used to suppress because the output of the undesired signal that external impact produces also can suppress the wide response of looking genuine.Therefore, can block the undesired signal of telecommunication of these circuit 100 outputs, thereby reduce the noise of loud speaker 116.
In above-mentioned piezo-electric resonator 10, can adopt any one method of cutting apart electrode 14, can both eliminate opposite polarity electric charge that in peripheral part 14a and 14c, produces and the electric charge that in middle body 14b, produces.That is, to have area identical be necessary in the electric charge place that the area of peripheral part 14a and 14c is equal to each other and middle body 14b may produce opposite polarity.This is divided into the part that the center line with respect to substrate 12 is mutually symmetrical to electrode 14 with regard to requiring, but divided portion needn't be parallel to each other.In addition, can on electrode 14, slot and cut apart, replace and on the whole surface of planar substrate 12, form an electrode earlier, then, by only producing electrode 14 or 16 such as methods such as etchings.
And, can be divided into electrode 14 and 16 more than three parts, for example four or five parts.If as shown in figure 24 electrode 14 is divided into four part 14a to 14d, then can connects into peripheral electrode part 14a and 14d as an I/O end 22, and interior electrode part 14b and 14c are coupled to as another I/O end 24.In this case, only to be mutually symmetrical be necessary to the center line that extends with respect to piezoelectric substrate longitudinally 12 of peripheral part 14a and 14d, and interior electrode part 14b and 14c needn't form around center line and be mutually symmetrical.Can be coupled these parts 14b and 14c each other, to eliminate the opposite polarity electric charge that produces owing to external impact.
As shown in figure 25, also can be divided into five part 14a to 14e to electrode 14.In this variation, can connect into peripheral part 14a and 14e as an I/O end 22, and three interior electrode part 14b, 14c and 14d connected into the effect of another I/O end 24.In this case, only to be mutually symmetrical be necessary to the center line that extends with respect to substrate longitudinally 12 of peripheral part 14a and 14e, and interior electrode part 14b, 14c and 14d needn't be mutually symmetrical around center line. Connection electrode part 14b, 14c and 14d can offset because the opposite polarity electric charge that external impact produces.
In above-mentioned variation, as shown in figure 26, can be coupled to middle body 14c to peripheral part 14a and 14e, as an I/O end 22.Rest parts 14b and 14d can connect into as another I/O end 24.In this method of attachment, require divided portion to be mutually symmetrical, to eliminate the opposite polarity electric charge that produces owing to external impact with respect to the center line of substrate 12 extensions longitudinally.
In the above-mentioned example that electrode is divided into more than three parts, if the gross area of the electrode part that is connected to an I/O end 22 is made the gross area of the electrode part that equals to be coupled to another I/O end 24 substantially, then the electric capacity between I/O end 22 and the electrode 16 can and the other end 24 and electrode 16 between electric capacity identical.Therefore, can be in I/O end 22 or 24 any as input or output, just draw the characteristic identical with resonator 10.In addition, the width of all electrode parts equates to avoid producing the minimum part of width, thereby prevents to damage piezoelectric substrate and electrode during with small pieces micromachined resonator 10.
In this form, the electrode 14 of piezo-electric resonator 10 can be divided into more than three parts, in this case, can offset because the electric charge that external impact produces with the suitable electrode part method of attachment that separates.Can use a kind of suitable dividing method according to selected method of attachment, promptly whether divided portion is mutually symmetrical with respect to center line.No matter use which kind of method, all require two peripheral parts to be mutually symmetrical around the center line of substrate 12.
Claims (16)
1, a kind of piezo-electric resonator, it comprises:
Make the flat piezoelectric substrate of rectangle; With
Be formed on two lip-deep two electrodes of described piezoelectric substrate, at least one described electrode is divided at least three parts along the width of described piezoelectric substrate, the two peripheral electrodes part of electrode separately is with respect to being mutually symmetrical along the center line of described piezoelectric substrate with longitudinal extension
Wherein, the described electrode that separates and another electrode are used separately as two I/O end and earth terminals, and described at least two peripheral electrodes of the described electrode that separates partly connect into as one of described I/O end.
2, piezo-electric resonator according to claim 1, it is characterized in that, described two electrodes at least one of them with three partial parallels separating in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the overall width of described peripheral electrode part equals the width of contre electrode part separately.
3, piezo-electric resonator according to claim 1, it is characterized in that, described two electrodes at least one of them with three partial parallels separating in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the width of described each peripheral electrode part equals the width of contre electrode part separately.
4, according to claim 1, one of 2 and 3 described piezo-electric resonators, it is characterized in that, one conduction supporter is being fixed on one node location of described piezoelectric substrate on the electrode separately, and the described electrode that separates is connected to the pattern electrodes that is formed on the insulating substrate by described supporter.
5, a kind of filter, comprise the piezo-electric resonator that a plurality of and described filter links to each other, the wherein described at least interior piezo-electric resonator of final stage that is arranged on described a plurality of piezo-electric resonators comprises: one makes the flat piezoelectric substrate of rectangle and is formed on two lip-deep two electrodes of described piezoelectric substrate, at least one described electrode is divided at least three parts along the width of described piezoelectric substrate, the two peripheral electrodes part of electrode separately is with respect to being mutually symmetrical along the center line of described piezoelectric substrate with longitudinal extension, the described electrode that separates and another electrode are used separately as two I/O end and earth terminals, at least described two peripheral electrodes of the electrode that separates are partly connected into as one of described I/O end.
6, filter according to claim 5, it is characterized in that, in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the overall width of described peripheral electrode part equals the width of contre electrode part separately to one of them of described final stage piezo-electric resonator described electrode with three partial parallels separating.
7, filter according to claim 5, it is characterized in that, in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the width of described each peripheral electrode part equals the width of contre electrode part separately to one of them of described final stage piezo-electric resonator described electrode with three partial parallels separating.
8, according to claim 5, one of 6 and 7 described filters, it is characterized in that, one conduction supporter is being fixed on one node location of described piezoelectric substrate on the electrode that described final stage piezo-electric resonator separates, and the described electrode that separates is connected to the pattern electrodes that is formed on the insulating substrate by described supporter.
9, a kind of AM receiving circuit comprises:
Mixting circuit is used for the signal that receives and the signal of local-oscillator circuit are carried out mixing;
Intermediate-frequency filter is used for taking out intermediate-freuqncy signal from the output signal of described mixting circuit; With
Detecting circuit is used for detecting voice signal from the intermediate-freuqncy signal that obtains in described intermediate-frequency filter,
Wherein, described intermediate-frequency filter adopts a piezo-electric resonator, described piezo-electric resonator comprises: one makes the flat piezoelectric substrate of rectangle and is formed on two lip-deep two electrodes of described piezoelectric substrate, at least a described electrode is divided at least three parts along the width of described piezoelectric substrate, the two peripheral electrodes part of electrode separately is with respect to being mutually symmetrical along the center line of described piezoelectric substrate with longitudinal extension, the described electrode that separates and another electrode are used separately as two I/O end and earth terminals, at least described two peripheral electrodes of the electrode that separates are partly connected into as one of described I/O end.
10, AM receiving circuit according to claim 9, it is characterized in that, in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the overall width of described peripheral electrode part equals the width of contre electrode part separately to one of them of described piezo-electric resonator described electrode with three partial parallels separating.
11, AM receiving circuit according to claim 9, it is characterized in that, in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the width of described each peripheral electrode part equals the width of contre electrode part separately to one of them of described piezo-electric resonator described electrode with three partial parallels separating.
12, according to claim 9, one of 10 and 11 described AM receiving circuits, it is characterized in that, one conduction supporter is being fixed on one node location of described piezoelectric substrate on the electrode that described piezo-electric resonator separates, and the described electrode that separates is connected to the pattern electrodes that is formed on the insulating substrate by described supporter.
13, a kind of AM receiving circuit comprises:
Mixting circuit is used for the signal that receives and the signal of local-oscillator circuit are carried out mixing;
Intermediate-frequency filter is used for taking out intermediate-freuqncy signal from the output signal of described mixting circuit; With
Detecting circuit is used for detecting voice signal from the intermediate-freuqncy signal that obtains in described intermediate-frequency filter,
Wherein, described intermediate-frequency filter adopts a kind of filter that comprises a plurality of piezo-electric resonators that are connected thereto, at least the described piezo-electric resonator that is arranged in described a plurality of piezo-electric resonator final stage comprises the flat piezoelectric substrate of making rectangle and is formed on two lip-deep two electrodes of described piezoelectric substrate, at least one described electrode is divided at least three parts along the width of described piezoelectric substrate, the two peripheral electrodes part of electrode separately is with respect to being mutually symmetrical along the center line of described piezoelectric substrate with longitudinal extension, the described electrode that separates and another electrode are used separately as two I/O end and earth terminals, at least described two peripheral electrodes of the electrode that separates are partly connected into as one of described I/O end.
14, AM receiving circuit according to claim 13, it is characterized in that, in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the overall width of described peripheral electrode part equals the width of contre electrode part separately to one of them of described final stage piezo-electric resonator described electrode with three partial parallels separating.
15, AM receiving circuit according to claim 13, it is characterized in that, in dividing in the mode of the center line of longitudinal extension along described piezoelectric substrate, the width of described each peripheral electrode part equals the width of contre electrode part separately to one of them of described final stage piezo-electric resonator described electrode with three partial parallels separating.
16, according to claim 13, one of 14 and 15 described AM receiving circuits, it is characterized in that, one conduction supporter is being fixed on one node location of described piezoelectric substrate on the electrode that the final stage piezo-electric resonator separates, and the described electrode that separates is connected to the pattern electrodes that is formed on the insulating substrate by described supporter.
Applications Claiming Priority (6)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP61946/96 | 1996-02-22 | ||
| JP61946/1996 | 1996-02-22 | ||
| JP6194696 | 1996-02-22 | ||
| JP014582/1997 | 1997-01-10 | ||
| JP014582/97 | 1997-01-10 | ||
| JP01458297A JP3331893B2 (en) | 1996-02-22 | 1997-01-10 | Piezoelectric resonator and filter and AM receiving circuit using the same |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN1160310A CN1160310A (en) | 1997-09-24 |
| CN1135692C true CN1135692C (en) | 2004-01-21 |
Family
ID=26350547
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CNB971026580A Expired - Lifetime CN1135692C (en) | 1996-02-22 | 1997-02-21 | Piezo-resonator, and filter and AM receiving circuitry using the same resonator |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JP3331893B2 (en) |
| CN (1) | CN1135692C (en) |
| DE (1) | DE19706796C2 (en) |
Families Citing this family (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP3368214B2 (en) * | 1997-10-01 | 2003-01-20 | 株式会社村田製作所 | Ladder filter and communication equipment |
| JPH11112280A (en) * | 1997-10-03 | 1999-04-23 | Murata Mfg Co Ltd | Electronic component and ladder filter |
| KR101588922B1 (en) * | 2012-12-12 | 2016-01-26 | 삼성전기주식회사 | Vibrator including a piezo actuator |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01236719A (en) * | 1988-03-16 | 1989-09-21 | Matsushita Electric Ind Co Ltd | Ceramic resonance element |
| JPH086734B2 (en) * | 1993-04-30 | 1996-01-29 | 若井産業株式会社 | Auxiliary tool for fixing screws to concrete, etc. |
-
1997
- 1997-01-10 JP JP01458297A patent/JP3331893B2/en not_active Expired - Lifetime
- 1997-02-20 DE DE1997106796 patent/DE19706796C2/en not_active Expired - Lifetime
- 1997-02-21 CN CNB971026580A patent/CN1135692C/en not_active Expired - Lifetime
Also Published As
| Publication number | Publication date |
|---|---|
| JP3331893B2 (en) | 2002-10-07 |
| DE19706796C2 (en) | 1999-09-30 |
| JPH09289432A (en) | 1997-11-04 |
| CN1160310A (en) | 1997-09-24 |
| DE19706796A1 (en) | 1997-08-28 |
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Granted publication date: 20040121 |