US2095376A - Piezoelectric oscillator crystal - Google Patents

Piezoelectric oscillator crystal Download PDF

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Publication number
US2095376A
US2095376A US3979635A US2095376A US 2095376 A US2095376 A US 2095376A US 3979635 A US3979635 A US 3979635A US 2095376 A US2095376 A US 2095376A
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Prior art keywords
crystal
metallic
coat
oscillator
layer
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Expired - Lifetime
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Bechmann Rudolf
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Telefunken AG
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Telefunken AG
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    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/125Driving means, e.g. electrodes, coils
    • H03H9/13Driving means, e.g. electrodes, coils for networks consisting of piezo-electric or electrostrictive materials
    • H03H9/132Driving means, e.g. electrodes, coils for networks consisting of piezo-electric or electrostrictive materials characterized by a particular shape
    • HELECTRICITY
    • H03BASIC ELECTRONIC CIRCUITRY
    • H03HIMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS
    • H03H9/00Networks comprising electromechanical or electro-acoustic devices; Electromechanical resonators
    • H03H9/02Details
    • H03H9/125Driving means, e.g. electrodes, coils
    • H03H9/13Driving means, e.g. electrodes, coils for networks consisting of piezo-electric or electrostrictive materials
    • H03H9/131Driving means, e.g. electrodes, coils for networks consisting of piezo-electric or electrostrictive materials consisting of a multilayered structure
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S125/00Stone working
    • Y10S125/901Stone working forming piezoelectric crystals

Description

Oct. 12, 1937. RQBECHMANN 2,095,376

PIEZOELECTRIC OSCILLATOR CRYSTAL Filed Sept. 9, 1955 INVE O RUDOLF BE M ATTORNEY.

Patented Oct. 12, 1937 UNITED STATES PATENT OFFICE PIEZOELECTRIC OSCILLATOR CRYSTAL tion of Germany Application September 9, 1935, Serial No. 39,796

In Germany November 24, 1934 7 Claims.

This invention is concerned with a piezo-electric oscillator arrangement in which the electrodes consist of metallization of the active or working surfaces. of the crystal.

It has been suggested in the earlier art to make the electrode surfaces of a piezo-electric oscillator or resonator by having the active areas of the crystal metalllzed. However, this method was soon abandoned for the reason that the crystal, after being in operation a comparatively short time, was found to lose its oscillation powers or experienced changes in frequency. Now, the present invention is predicated upon the idea and proper appreciation of the fact that these unfavorable results were ascribable to the circumstance that the electrode surface was destroyed or impaired by extraneous influences such as atmospheric humidity or thermal conditions inside the crystal holder.

According to this invention, the electrode surfaces are made by applying a coat of heat and humidity resisting material upon the active surfaces of the crystal and being of a kind which will not suffer oxidation. Materials suited for this purpose are gold, platinum, and chromium.

In order to insure particularly good sticking or adhesion of the metallic coat upon the crystal, the said coat is applied in two or more thin layers rather than a heavy layer being applied all at once. Experience has shown that especially favorable results are obtained if at least the bottom coat or substratum adjacent the surface of the crystal is produced by way of cathode disintegration. This bottom coat could consist also of other or dissimilar metals, e. g., silver, while at least the outermost or top coat consists of other metals presenting heat and humidity resisting qualities, as mentioned above.

To a certain extent, the frequency of a'crystal 4O oscillator is also dependent somewhat on the thickness of the metallic coat. The latter, as it were, represents a load or impediment for the mechanical oscillable system in such a way that with changing thickness of the coat the mass of the oscillator increases, and this means a reduction in the natural frequency of the structure or oscillating system. This phenomenon is encountered in all kinds of crystal oscillators; it is only the magnitude of its influence upon the natural frequency of the various forms of oscillation which are possible to obtain in a given crystal. In the light of this situation it will be obvious that with the use of metals which are not stable in reference to humidity actions, the mass of the oscillable structure, for instance, may undergo a change by oxidation of the metal and thus a structural change in the metallic coat or layer occurs.

According to the invention, these conditions are utilized for the practical purpose to cause the frequency of the oscillable crystal to assume a value that may be fixed with a high degree of precision. This" method is particularly adapted to the said object for the reason that, on the one hand, the thickness or depth of the metallic coat is producible with a good deal of exactitude, while on the other hand, any desired slight variation of the coat thickness is obtainable. To make the metallic coat, apart from the cathode disintegration hereinbefore mentioned, there is suited also the process predicated upon the vaporization of metal in vacuo as well as the application of the coat inside an electrolytic bath. In this case it is possible to exactly determine and gauge the thickness of the layer by measuring and controlling the length of action of the application or filming process.

One exemplified embodiment of the basic idea of the invention is shown in the attached drawing in which Fig. 1 is a perspective view of the crystal with metallic films and Fig. 2 is a crosssectional View of Fig. 1. Referring now in detail to the drawing, l denotes a circular plate made of a kind of material possessing piezo-electric properties, such as quartz crystal. The active surfaces of the crystal consist of the flat faces of the disk 2 and 2. Applied upon each of the active surfaces are metallic coats 3, 4, and 3', 4', respectively, at least the top layers 4 and 4' consisting of a non-oxidizing metal having heat and humidity resisting qualities, e. g., gold, platinum, or chromium; whereas the lower layers 3 and 3, respectively, may consist of a different metal having a lower melting point and subject to greater oxidization but having better electrical conducting properties, such as silver.

Having thus described my invention, what I claim is:

1. A piezo-electric crystal oscillator having a plurality of metallic films to act as the electrodes, with this characteristic feature that each one of the metallic films consists of at least two different metallic conducting layers of which at least the topmost one is made of material which resists heat and humidity actions.

2. An oscillator crystal according to claim 1, with this characteristic feature that the topmost layer consists of a film of gold.

3. An oscillator crystal according to claim 1 with this characteristic feature that the topmost the metallic films consists of at least two difierent metallic conducting layers of which the layer in intimate contact with the crystal is of silver and the topmost layer is of gold. I

6. A piezo-electric crystal oscillator having a plurality of metallic films to act as'electrodes with this characteristic feature that each one of the metallic films consists of at least two different metallic conducting layers of which the layer in intimate contact with the crystal is of silver and the topmost layer is of platinum.

7. A piezo-electric crystal oscillator having a plurality of metallic films to act as electrodes with this characteristic feature that each one of the metallic films consists of at least two different metallic conducting layers of which thelayer in intimate contact with the crystal is of silver and the topmost layer is of chromium.

RUDOLF BECI-IMANN.

US2095376A 1934-11-24 1935-09-09 Piezoelectric oscillator crystal Expired - Lifetime US2095376A (en)

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Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2482661A (en) * 1946-08-15 1949-09-20 Rca Corp Crystal mounting
US2497666A (en) * 1945-05-04 1950-02-14 Brush Dev Co Electrode for piezoelectric crystals
US2510811A (en) * 1942-12-08 1950-06-06 Scophony Corp Piezoelectric crystal
US2546321A (en) * 1949-02-12 1951-03-27 Bell Telephone Labor Inc Piezoelectric crystal apparatus
US2575819A (en) * 1949-02-03 1951-11-20 Bell Telephone Labor Inc Crystal unit
US3721841A (en) * 1971-06-16 1973-03-20 Motorola Inc Contact for piezoelectric crystals
US3831043A (en) * 1971-12-28 1974-08-20 Siemens Ag Piezoelectric oscillator arrangements
US4213071A (en) * 1976-10-14 1980-07-15 Interatom Internationale Atomreaktorbau Gmbh Oxygen filled, sealed housing for piezoceramic electroacoustic transducer
US4266156A (en) * 1977-11-15 1981-05-05 Citizen Watch Co., Ltd. Subminiature piezoelectric quartz vibrator
US4443730A (en) * 1978-11-15 1984-04-17 Mitsubishi Petrochemical Co., Ltd. Biological piezoelectric transducer device for the living body
US4517485A (en) * 1982-06-01 1985-05-14 Compagnie D'electronique Et De Piezo-Electricite High-frequency piezoelectric resonator with reinforced electrode connection
US6025669A (en) * 1996-07-01 2000-02-15 Murata Manufacturing Co., Ltd. Piezoelectric resonator and piezoelectric components using the same
CN102525432A (en) * 2010-12-29 2012-07-04 深圳市迈迪加科技发展有限公司 Heart function sensor
CN102551706A (en) * 2010-12-31 2012-07-11 深圳市迈迪加科技发展有限公司 Fetal sound sensor
CN102551725A (en) * 2010-12-27 2012-07-11 深圳市迈迪加科技发展有限公司 Novel breath sensor

Cited By (16)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2510811A (en) * 1942-12-08 1950-06-06 Scophony Corp Piezoelectric crystal
US2497666A (en) * 1945-05-04 1950-02-14 Brush Dev Co Electrode for piezoelectric crystals
US2482661A (en) * 1946-08-15 1949-09-20 Rca Corp Crystal mounting
US2575819A (en) * 1949-02-03 1951-11-20 Bell Telephone Labor Inc Crystal unit
US2546321A (en) * 1949-02-12 1951-03-27 Bell Telephone Labor Inc Piezoelectric crystal apparatus
US3721841A (en) * 1971-06-16 1973-03-20 Motorola Inc Contact for piezoelectric crystals
US3831043A (en) * 1971-12-28 1974-08-20 Siemens Ag Piezoelectric oscillator arrangements
US4213071A (en) * 1976-10-14 1980-07-15 Interatom Internationale Atomreaktorbau Gmbh Oxygen filled, sealed housing for piezoceramic electroacoustic transducer
US4266156A (en) * 1977-11-15 1981-05-05 Citizen Watch Co., Ltd. Subminiature piezoelectric quartz vibrator
US4443730A (en) * 1978-11-15 1984-04-17 Mitsubishi Petrochemical Co., Ltd. Biological piezoelectric transducer device for the living body
US4517485A (en) * 1982-06-01 1985-05-14 Compagnie D'electronique Et De Piezo-Electricite High-frequency piezoelectric resonator with reinforced electrode connection
US4656707A (en) * 1982-06-01 1987-04-14 Compagnie D'electronique Et De Piezo-Electricite Method of fabricating a high-frequency piezoelectric resonator
US6025669A (en) * 1996-07-01 2000-02-15 Murata Manufacturing Co., Ltd. Piezoelectric resonator and piezoelectric components using the same
CN102551725A (en) * 2010-12-27 2012-07-11 深圳市迈迪加科技发展有限公司 Novel breath sensor
CN102525432A (en) * 2010-12-29 2012-07-04 深圳市迈迪加科技发展有限公司 Heart function sensor
CN102551706A (en) * 2010-12-31 2012-07-11 深圳市迈迪加科技发展有限公司 Fetal sound sensor

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