GB2067009A - Encapsulated piezo-electric resonator - Google Patents
Encapsulated piezo-electric resonator Download PDFInfo
- Publication number
- GB2067009A GB2067009A GB8037849A GB8037849A GB2067009A GB 2067009 A GB2067009 A GB 2067009A GB 8037849 A GB8037849 A GB 8037849A GB 8037849 A GB8037849 A GB 8037849A GB 2067009 A GB2067009 A GB 2067009A
- Authority
- GB
- United Kingdom
- Prior art keywords
- casing
- adsorbant
- resonator
- elements
- resonator according
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Withdrawn
Links
- 239000000463 material Substances 0.000 claims abstract description 22
- 239000000853 adhesive Substances 0.000 claims abstract description 21
- 230000001070 adhesive effect Effects 0.000 claims abstract description 21
- 229910052788 barium Inorganic materials 0.000 claims abstract description 4
- DSAJWYNOEDNPEQ-UHFFFAOYSA-N barium atom Chemical compound [Ba] DSAJWYNOEDNPEQ-UHFFFAOYSA-N 0.000 claims abstract description 4
- 238000007789 sealing Methods 0.000 claims description 7
- 230000000737 periodic effect Effects 0.000 claims description 6
- 239000000956 alloy Substances 0.000 claims description 4
- 229910045601 alloy Inorganic materials 0.000 claims description 4
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 239000004020 conductor Substances 0.000 claims description 2
- 230000003534 oscillatory effect Effects 0.000 claims 2
- 229910052729 chemical element Inorganic materials 0.000 claims 1
- 238000000638 solvent extraction Methods 0.000 claims 1
- 239000011521 glass Substances 0.000 abstract description 6
- 238000009792 diffusion process Methods 0.000 abstract description 3
- 239000003822 epoxy resin Substances 0.000 abstract description 3
- 229920000647 polyepoxide Polymers 0.000 abstract description 3
- 230000000694 effects Effects 0.000 abstract description 2
- 239000003463 adsorbent Substances 0.000 abstract 2
- 230000006866 deterioration Effects 0.000 abstract 1
- 239000010410 layer Substances 0.000 description 7
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 4
- 239000012790 adhesive layer Substances 0.000 description 2
- 238000007872 degassing Methods 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 229910052792 caesium Inorganic materials 0.000 description 1
- TVFDJXOCXUVLDH-UHFFFAOYSA-N caesium atom Chemical compound [Cs] TVFDJXOCXUVLDH-UHFFFAOYSA-N 0.000 description 1
- 229910010293 ceramic material Inorganic materials 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- WPBNNNQJVZRUHP-UHFFFAOYSA-L manganese(2+);methyl n-[[2-(methoxycarbonylcarbamothioylamino)phenyl]carbamothioyl]carbamate;n-[2-(sulfidocarbothioylamino)ethyl]carbamodithioate Chemical compound [Mn+2].[S-]C(=S)NCCNC([S-])=S.COC(=O)NC(=S)NC1=CC=CC=C1NC(=S)NC(=O)OC WPBNNNQJVZRUHP-UHFFFAOYSA-L 0.000 description 1
- 229910052751 metal Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 238000000034 method Methods 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 238000005192 partition Methods 0.000 description 1
- 239000010453 quartz Substances 0.000 description 1
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicon dioxide Inorganic materials O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 1
- 238000005476 soldering Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
Classifications
-
- 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
- H03H9/1021—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 the BAW device being of the cantilever type
-
- G—PHYSICS
- G04—HOROLOGY
- G04F—TIME-INTERVAL MEASURING
- G04F5/00—Apparatus for producing preselected time intervals for use as timing standards
- G04F5/04—Apparatus for producing preselected time intervals for use as timing standards using oscillators with electromechanical resonators producing electric oscillations or timing pulses
- G04F5/06—Apparatus for producing preselected time intervals for use as timing standards using oscillators with electromechanical resonators producing electric oscillations or timing pulses using piezoelectric resonators
- G04F5/063—Constructional details
-
- 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
- H03H9/02007—Details of bulk acoustic wave devices
- H03H9/02086—Means for compensation or elimination of undesirable effects
Landscapes
- Physics & Mathematics (AREA)
- Acoustics & Sound (AREA)
- General Physics & Mathematics (AREA)
- Piezo-Electric Or Mechanical Vibrators, Or Delay Or Filter Circuits (AREA)
Abstract
An encapsulated piezo-electric resonator (5) having a casing made e.g. of glass and comprising a cover (2) and a body (1) sealed together by means of an organic adhesive, e.g. epoxy resin. This adhesive allows moisture to pass into the casing by diffusion, which tends to result in variation of the frequency of the resonator and deterioration of its effective Q factor. Such undesired effect of internal moisture is substantially eliminated by means of a body (7) of adsorbent material, for instance of a Group I or Group II element, e.g. barium, located within the casing for adsorbing this moisture. The adsorbent body may be, as shown, a plate or layer (7) on the underside of the cover (2), or a bar in another compartment in the casing. <IMAGE>
Description
SPECIFICATION
Encapsulated piezo-electric resonator
BACKGROUND OF THE INVENTION
1. Field of the invention
This invention relates to an encapsulated piezo-electric resonator.
2. Description of the Prior Art
Resonators are known which are encapsulated in flat casings constituted by two elements of parallelepiped shaped, namely a body and a cover made of glass, as well as resonators with entirely metallic casings and resonators the casings of which comprise a body made of ceramic material and a cover made of glass.
These casings have to be well sealed, as it is a necessary condition for operation that such piezo-electric resonators are under reduced pressure and thus operate with low air loading. This is especially so with low frequency resonators, having the shape of a tuning-fork as used in electronic timepieces.
Consequently the problem of sealing the component elements of the casing is of the greatest importance.
For this purpose a closing means which is entirely metallic (soldering or cold clenching of two soft metals of which the elements of the casing are made) may be used, but this requires provision of passages through the casing for the entry of electrical connections for driving the resonator and for receiving electrical information.
It has also been suggested that the sealing of the elements of the casing should be achieved by means of an organic adhesive, especially epoxy resin. This solution is much simple and more easily carried out. Moreover, since the adhesive used is insulating, it is easier to arrange for the conductors to pass through the sealing interface.
Unfortunately, these adhesives are not impervious to water which traverses them by diffusion. That is a serious drawback since the piezo-electric resonators are sensitive to moisture. It has been ascertained, for instance, that the presence of water in the casing under a pressure corresponding to a relative moisture of 80% at 25"C, produces a variation of the frequency of the resonator and a decrease of more than 50% of the Q factor of the equivalent resonant circuit, which is unacceptable.
SUMMARY OF THE INVENTION
The main object of the present invention is to provide a resonator with a casing the elements of which are sealed by means of an organic adhesive, with the resultant advantages already mentioned while at the same time eliminating the unfavourable consequence of the permeability to moisture exhibited by such adhesives.
This object is achieved by providing the casing of the resonator with at least a body which adsorbs the moisture which diffuses into the casing.
Other features of the invention will be apparent from the following description, drawings and claims, the scope of the invention not being limited to the drawings themselves as the drawings are only for the purpose of illustrating ways in which the principles of the invention can be applied. Other embodiments of the invention utilising the same or equivalent principles may be used and structural changes may be made as desired by those skilled in the art without departing from the present invention and the purview of the appended claims.
BRIEF DESCRIPTION OF THE DRAWING
The accompanying drawing illustrates, by way of example, two embodiments of the invention. In the drawing:
Figure I is a plan view, partly in section along the line I-I of Fig. 2, of an encapsulated piezo-electric resonator according to a first embodiment;
Figure 2 is a longitudinal cross-sectional view of this resonator, along the line ll-ll of
Fig. 1;;
Figure 3 is a cross-sectional view of a portion of this resonator, along the line 11 I-Ill of Fig. 2, and
Figure 4 is a longitudinal cross-sectional view, similar to that of Fig. 2, of an encapsulated piezo-electric resonator according to the second embodiment,
DESCRIPTION OF THE PREFERRED EMBODI
MENTS
The casing of the resonator illustrated in
Figs. 1 to 3 is of the flat type, comprising two elements of parallelepiped shape, namely a body 1 and a cover 2, both made of glass and stuck to each other by a layer 3 of an organic adhesive material, for instance an epoxy resin.
The adhesive products known by the tradenames EPO-TEK H 77, Ablebond 789-1 and
Ablefilm 507 are particularly suitable for this purpose.
Two conductive tracks 4 are fixed on the upper face of the body 1 and pass through the adhesive layer 3 which is electrically insulating and consequently does not short circuit the tracks. A piezo-electric element 5, in this instance a quartz crystal having the shape of a tuning-fork, is stuck at its base 5a onto the upper face of the body 1, in electrical contact with the inner ends of the conductive tracks 4. The body 1 is provided with a recess 6, of rectangular shape, situated opposite to the arms of the tuning-fork 5.
So as to remedy the effects of the permeability of the adhesive 3 to moisture, the cover 2 is provided with a moisture-adsorbant body 7, stuck on the inner face of the cover 2 and intended to adsorb the moisture diffusing into the casing. This adsorbant body 7 is formed by a rectangular small plate of an element of the first or of the second group of the periodic table of the elements, or of an alloy of at least two elements of the first and/or of the second group of the periodic table, or else of an alloy of aluminum with at least one element of the first and/or of the second group of the periodic table. Manganese, barium or caesium are particularly usable, barium, being specially suitable due to its high adsorption capacity.
The dimensions of the adsorbant small plate 7 are determined by the degree of resistance to the diffusion of moisture presented by the adhesive used, by the dimensions of the casing and by the desired effective life of the resonator. In cases where it is possible to achieve a thin adhesive layer using an adhesive of good quality, the small plate 7 can be replaced by a layer of adsorbant material deposited on the underside of the cover 2 by evaporation under vacuum or by any other method.
It should be noted that the role played by the adsorbant material placed in the casing is very different from that of the adsorbant materials placed, for instance, in the tubes of electronic components. In the latter case, the object of the material is to adsorb the products of degassing resulting from the sealing of the tube. Consequently, the material must adsorb the products of decomposition of the glass and this during a relatively short period of time (up to completion of the degassing of the tube). Subsequently, the adsorbant material does not play any further role. In contrast, in the present case the adsorbant material must adsorb water vapour throughout the working life of the encapsulated resonator.
Fig. 4 shows a second embodiment of the resonator also having a flat type casing made of glass. The casing comprises a body 8 and a cover 9 sealed to each other by a layer 10 of organic adhesive material. It differs from the first embodiment by the fact that the internal space of the casing is divided into two compartments 11 and 1 2 by an internal partition wall made up of two portions 8a and 9a which are respectively parts of the body 8 and the cover 9 of the casing. The facing ends of these portions 8a and 9a are not coated with the adhesive material, so that the compartments 11 and 1 2 communicate one with the other.The first of. these compartments contains the resonating element constituted, as in the first embodiment, by a tuning-fork 5; in the second there is located a bar 1 3 of a material which adsorbs the moisture which diffuses through the layer 10 of the adhesive material.
This arrangement is particularly suitable in the case where the adsorbant material has a tendency to increase its volume as it adsorbs moisture.
It should be noted the casing of the resona- tor may also contain an integrated circuit comprising the oscillator circuit with which the piezo-electric resonator is associated.
It should also be added that, in some cases, the casing can comprise more than two elements. This is the case when the resonator, having the shape of a tuning-fork, is surrounded by a frame of which it constitutes an integral part. The frame is then sandwiched between the upper and lower elements of the casing. The invention is clearly also applicable to the case of such an encapsulated resonator, in order to adsorb the water vapour diffusing through the two layers of adhesive material disposed between the frame and the upper and lower elements.
As a result of the introduction into the casing of the adsorbant material, it is actually possible to produce an encapsulated resonator of good quality at reduced cost. On the one hand, it permits the use of an organic material adhesive in spite of the inherent lack of perfect sealing qualities. On the other hand, it is possible for the electrical connections to pass out at the level of the sealing layer since this layer is electrically insulating. It is thus not necessary to drill the casing to provide passages for the electrical connecting wires.
Claims (10)
1. An encapsulated piezo-electric resonator comprising: a a casing constituted by at least two ele- ments; - an oscillatory piezo-electric element secured to the said casing; - at least one layer of organic adhesive material for sealing with respect to each other the said elements of the casing; and - a moisture adsorbant body placed within the said casing for adsorbing the moisture which progressively diffuses into the casing through said layer of adhesive material.
2. -A resonator according to claim 1, wherein the said adsorbant body is constituted by an element belonging to the first or to the second group of the periodic table of the elements.
3. A resonator according to claim 2, wherein the said element is barium.
4. A resonator according to claim 1, wherein the said adsorbant body is constituted by an alloy of at least two elements of the first and/or of the second group of the periodic table of the elements.
5. A resonator according to claim 1, wherein the said adsorbant body is constituted by an alloy of aluminum with at least one element of the first and/or of the second group of the periodic table of the elements.
6. A resonator according to claim 1, wherein one of the said elements constitutes a cover for the casing and wherein the said adsorbant body is constituted by a small plate of adsorbant material stuck under the said cover.
7. A resonator according to claim 1, wherein one of the said elements constitutes a cover for the casing and wherein the said adsorbant body is constituted by a layer of adsorbant material deposited on the underside of the said cover.
8. A resonator according to any one of claims 1 to 5, further comprising means for partitioning the casing into two compartments, one such compartment containing the oscillatory element and the other of the compartments containing the adsorbant body.
9. A resonator according to any one of claims 1 to 5, wherein the adhesive material is insulating, the said resonator further comprising at least one electrical conductor traversing the said casing at the level of the said layer of adhesive material.
10. A piezo-electric resonator constructed and arranged substantially as herein particularly described with reference to and as illustrated in Figs. 1 to 3, or Fig. 4, of the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CH1118379 | 1979-12-17 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| GB2067009A true GB2067009A (en) | 1981-07-15 |
Family
ID=4370891
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8037849A Withdrawn GB2067009A (en) | 1979-12-17 | 1980-11-26 | Encapsulated piezo-electric resonator |
Country Status (2)
| Country | Link |
|---|---|
| JP (1) | JPS5698015A (en) |
| GB (1) | GB2067009A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2132816A (en) * | 1982-12-23 | 1984-07-11 | Kung Chao Tung | Quartz oscillators |
| GB2146839A (en) * | 1983-07-27 | 1985-04-24 | Nihon Dempa Kogyo Co | Piezoelectric resonator |
| US5396144A (en) * | 1993-08-02 | 1995-03-07 | New S.D., Inc. | Rotation rate sensor with center mounted tuning fork |
| US5420472A (en) * | 1992-06-11 | 1995-05-30 | Motorola, Inc. | Method and apparatus for thermal coefficient of expansion matched substrate attachment |
| US5436523A (en) * | 1992-11-06 | 1995-07-25 | Avance Technology | High frequency crystal resonator |
| US5585687A (en) * | 1994-02-23 | 1996-12-17 | Citizen Watch Co., Ltd. | Piezolelectric oscillator |
| WO1997023951A1 (en) * | 1995-12-21 | 1997-07-03 | Siemens Matsushita Components Gmbh & Co. Kg | Electronic component, especially one operating with acoustic surface waves (sw component) |
| US8087135B2 (en) | 2007-12-04 | 2012-01-03 | Seiko Instruments Inc. | Method of manufacturing a piezoelectric vibrator |
| EP1664731B1 (en) * | 2003-03-21 | 2012-02-22 | MEAS France | Resonator sensor assembly |
| US8732938B2 (en) | 2003-03-21 | 2014-05-27 | MEAS France | Method of packaging a sensor |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02113430U (en) * | 1989-02-27 | 1990-09-11 |
-
1980
- 1980-11-26 GB GB8037849A patent/GB2067009A/en not_active Withdrawn
- 1980-12-17 JP JP17867280A patent/JPS5698015A/en active Pending
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2132816A (en) * | 1982-12-23 | 1984-07-11 | Kung Chao Tung | Quartz oscillators |
| GB2146839A (en) * | 1983-07-27 | 1985-04-24 | Nihon Dempa Kogyo Co | Piezoelectric resonator |
| US4639632A (en) * | 1983-07-27 | 1987-01-27 | Nihon Dempa Kogyo Co., Ltd. | Piezoelectric resonator mountings |
| US5420472A (en) * | 1992-06-11 | 1995-05-30 | Motorola, Inc. | Method and apparatus for thermal coefficient of expansion matched substrate attachment |
| US5436523A (en) * | 1992-11-06 | 1995-07-25 | Avance Technology | High frequency crystal resonator |
| US5396144A (en) * | 1993-08-02 | 1995-03-07 | New S.D., Inc. | Rotation rate sensor with center mounted tuning fork |
| US5585687A (en) * | 1994-02-23 | 1996-12-17 | Citizen Watch Co., Ltd. | Piezolelectric oscillator |
| WO1997023951A1 (en) * | 1995-12-21 | 1997-07-03 | Siemens Matsushita Components Gmbh & Co. Kg | Electronic component, especially one operating with acoustic surface waves (sw component) |
| US6136175A (en) * | 1995-12-21 | 2000-10-24 | Siemens Aktiengesellschaft | Method of producing an electronic component, in particular a surface acoustic wave component |
| EP1664731B1 (en) * | 2003-03-21 | 2012-02-22 | MEAS France | Resonator sensor assembly |
| US8732938B2 (en) | 2003-03-21 | 2014-05-27 | MEAS France | Method of packaging a sensor |
| US8087135B2 (en) | 2007-12-04 | 2012-01-03 | Seiko Instruments Inc. | Method of manufacturing a piezoelectric vibrator |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5698015A (en) | 1981-08-07 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4266156A (en) | Subminiature piezoelectric quartz vibrator | |
| US4360754A (en) | Mode suppressed piezoelectric device | |
| US4652787A (en) | Piezoelectric oscillator | |
| GB2067009A (en) | Encapsulated piezo-electric resonator | |
| US4750246A (en) | Method of making compensated crystal oscillator | |
| KR20030030895A (en) | Piezoelectric resonator and assembly comprising the same enclosed in a case | |
| US4742182A (en) | Flatpack for hermetic encapsulation of piezoelectric components | |
| US3754153A (en) | Crystal mounting assembly | |
| US4504766A (en) | Chip type discharge element with laminated insulating sheets | |
| US4234811A (en) | Supporting structure for a thickness-shear type crystal oscillator for watches | |
| JP3720355B2 (en) | Method for manufacturing frequency control device | |
| GB2029092A (en) | Piezo-electric oscillator assembly | |
| GB1448642A (en) | Oscillator case assembly | |
| JPS58138115A (en) | Chip-shaped piezoelectric oscillating component | |
| US4872937A (en) | Electrical component and method of mounting same | |
| US4283650A (en) | Piezo-vibrator unit ceramic package with integral capacitor | |
| JP2001007646A (en) | Piezoelectric oscillator | |
| US4045953A (en) | Circuit board for an electronic timepiece | |
| JPH10135771A (en) | Piezoelectric component | |
| JPS6118366B2 (en) | ||
| JPH08288701A (en) | Microwave integrated circuit device | |
| JP2001308214A (en) | Method and structure for sealing ceramic package | |
| JP3441349B2 (en) | Piezoelectric resonator with built-in capacitance | |
| JPH03240310A (en) | Piezoelectric resonator | |
| JPS5832332Y2 (en) | Electrode lead structure of tuning fork crystal resonator |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| WAP | Application withdrawn, taken to be withdrawn or refused ** after publication under section 16(1) |