US2012018A

US2012018A - Piezo-electric crystal apparatus

Info

Publication number: US2012018A
Application number: US586170A
Authority: US
Inventors: Osnos Mendel
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1931-01-14
Filing date: 1932-01-12
Publication date: 1935-08-20
Anticipated expiration: 1952-08-20

Description

Aug. 20, 1935. M. OSNOS PIEZO ELECTRIC CRYSTAL APPARATUS Filed Jan. 12, 1932 COOLING F'LIJID INVENTOR MENDEL OSNOS BY [1 /LO'U ATTORNEY Patented Aug. 20, 1935 l UNITED STATES PATENT OFFICE 2,012,018 PIEZO-ELEOTRIC CRYSTAL APPARATUS Mendel Osnos, Berlin, Germany, assignor to Telei'unken Gesellachatt fur Drahtlose Telegraphic m. b. II., Berlin, Germany, a corporation of Germany Application January 12, 1932, Serial No. 586,170 In Germany January 14, 1931 8 Claims. (Cl. 171-327) This invention relates to plezo-electric crystal tals, is set in a vessel containing oil, it is essential holders, and more particularly to a method of that the oil be absolutely precluded therefrom. and apparatus for cooling the crystal elements A Eeneml rule, a Diem-electric Crystal will fail contained within the holder. to oscillate in the oil. Now, in order to provide An object of this invention 15 to improve the conditions allowing of oscillating, the crystal and cooling of the crystal element by carefully shapmore particularly also its electrodes and crystaling and arranging the crystal electrodes with r setting means, is oil-tightly enclosed or encased spectto the cooling medium. by an insulating envelope, the leads brought to Heretofore radio apparatus used for transmik the electrodes being pa ed through said envelop 1o sion has been mainly cooled by placing the elecin a manner which w Insure t h es 1o trodes in contact ith circulating te Thi To diminish the losses occasioned by air which method of cooling results in many losses, such as, participates in the oscillations, it desirable to for example, the eddy-currents m the te d make the envelope of the crystal and the seals of in additio th re is good d l of wear md t the leads connected to the electrodes not only oil- :in rubber hose, noth r di a t has been tight, but also heremetically sealed, and to ex-. 15 that such cooling was never perfect, for the reahallst the 8 m e e ghborhood of son that only the electrodes were cooled and not the crystal in Order that the crystal y oscillate the entire unit. This disadvantage was especialinside elllwe being as free from air or gas as ly noticed where relatively large devices were in- Possiblevolved, the glass envelope or t nk containing th However, such an arrangement as above deapparatus r ain d very h t and thi resulted 1 scribed would render it harder to carry ofi such an impairment in the vacuimi and in low life 01 heat as is p ed y t e crystal. the apparatus. Such deficient glass cooling Therefore, according to the present invention came of particularly great inconv i 1 t the crystal alone is shut ofi from the outer surcase of tr nsmitter apparatus for h t wave roundings while the electrodes constitute part of 25 work, the enclosing envelope which at the same time 1 h v found that th disadvantages may be serve to secure more eflicient abduction of heat entirely or at least a maior portion 0! them elimifrom the cl'ystel t0 h a en hated by having the various devices such as piezo- The invention will be more completely underelectric crystals, inductance coils, condensers, restood y referring to he c mpanying dr win 30 sistances and vacuum tubes immersed in a tank in wh ch containing oil, the oil in the tank being optionally Fig. 1 is an axial cross-sectional view of a simcooled in any well-known manner. ple form of piezo-electric crystal holder;

Inthe case of short wave transmitters more par- Fig. 2 is a sectional view taken on lines A-A ticularly, one advantage offered by such arrangeof Pig. 1; 35 ment is that ii the resistance losses of the appa- Fig. 3 is an axial cross-sectional view of anratus are constant, the wavelength will be mainother modification of my invention, wherein the tained at a constant value. It is advisable to crystal holder is located within a vessel containmake the tank of highly conductive material, ing a. liquid.

such as copper, aluminum, etc, so as to provide Referring now in detail to Figs. 1 and 2 of the 40 reliable shielding. drawing, l is a. glass body, 2 a body made of glass One advantageous plan is to secure the appaor some other refractory insulation material, 3 ratus and tuning means to the cover of the oil and 4 metallic electrodes consisting most prefertank so that, on removing or lifting the cover the ably of copper. In the space between 3 and 4 there entire transmitter outfit is taken out of the oil. is to be mounted the crystal (not shown in the 45 It is a. well-known fact that the frequency of drawing). 2 is aspaced piece adapted to preserve, a valve transmitter, particularly in the case of for instance, a suitable distance between 3 and short waves, varies with the temperature of the 4, though not being rigidly united with 3 and 4 electrodes of the apparatus and of the tuning in any other manner.

means. In the arrangement described above, the The part I is fused together with 3 and 4, or 5 temperature of the transmitter is maintained is cemented in an oil and air-tight manner. The constant wholly, or practically so, in that the temair is exhausted by way of the pumping stem 6, perature of the oil is kept at a constant value by whereupon the latter is sealed ofi. means and ways well known in the prior art. The openings 5 serve the purpose of enlarging I 65 When apparatus, such as piezo-electric crysthe vacuous space in which the crystal is confined by the provision of the connection of the space between electrodes 3 and 4 with the space between i and 2, whereby the vacuum around the crystal is rendered less sensitive to such air as may happen to enter.

The modifications shown in Fig. 3 illustrates an improved manner in which the entire crystal holder is located within a vessel containing a cooling fluid, such as for example a high-grade insulation oil, or any other suitable liquid. The piezo-electric crystal electrodes are arranged in a manner to secure more eflicient cooling conditions by furnishing the portion of the electrodes which is exposed to the cooling fluid with radiator ribs or fins.

Having now described my invention, I claim:

1. A piezo-electric crystal holder comprising two electrodes, a pieZo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a flat plate, the other electrode being of the same perimeter as the first electrode and having a base portion from which a cylindrical portion extends upward for supporting the crystal, an inner spacing member to insulate and space said electrodes apart from each other, and an outer insulating side wall for closing the inner surfaces of said electrodes.

2. A piezoelectric crystal holder comprising two electrodes, a piezo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a flat plate, the other electrode being of the same perimeter as the first electrode and having a base portion from which a cylindrical portion extends upward for supporting the crystal, an inner spacing member concentric with said cylindrical portion to insulate and space said electrodes apart from each other, and an outer insulating side wall for closing the inner surfaces of said electrodes.

3. A piezo-electric crystal holder comprising two electrodes, a piezo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a flat plate, the other electrode being of the same perimeter as the first electrode and having a base portion from which a cylindrical portion extends upward for supporting the crystal, an inner spacing member concentric with the cylindrical portions so as to insulate and space said electrodes apart from each other, an outer insulating side wall for closing the inner surfaces of said electrodes, and at least one of said electrodes immersed in a cooling liquid.

4. A piezo-electric crystal holder comprising two electrodes, with cooling ribs, a piezo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a fiat plate, the other electrode being of the same perimeter having a base portion from which a cylindrical portion extends upward for supporting the crystal, said cylindrical portion having a greater exposed internal and external area than that of the crystal so as to serve as an efficient heat conducting surface for transferring the heat from the crystal to the ambient atmosphere, an inner'spacing member contained within the cylindrical portion to insulate and space said electrodes apart from ma ma.

each other, and an outer insulating side wall for closing the inner surfaces of said electrodes.

5. A piezo-electric crystal holder for use in a system adapted to keep the crystal at substantially constant temperature comprising two electrodes, a piezo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a relatively flat plate, the other electrode lying directly below the first mentioned electrode and having a base portion from which a cylindrical portion extends upwardly for supporting the crystal, said cylindrical base portion having a greater exposed external area than that of the crystal so as to serve as an eiiicient heat conducting surface to transfer the heat from the crystal to the ambient atmosphere, an inner spacing member contained within the confines of the cylindrical support member to space the electrodes apart from each other, and an outer insulating side wall for closing the inner surfaces of said electrodes.

6. A piezo-electric crystal holder comprising two electrodes, a piezo-electric crystal interposed between said electrodes, one of said electrodes in the form of a flat plate, the other electrode being of the same perimeter as the first electrode and having a base portion from which a cylindrical portion extends upward for supporting the crystal, an insulating spacing member concentric with the cylindrical portion, an insulating enveloping member for closing the inner surfaces of both electrodes, said enveloping member being exhausted of air and sealed.

7. A piezo-electric crystal holder comprising two electrodes, a piezo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a flat plate, the other electrode being of the same perimeter as the first electrode and having a base portion from which a cylindrical portion extends upward for supporting the crystal, an inner insulating spacing mem ber to insulate and space said electrodes apart from each other, said inner insulating spacing member having a plurality of apertures and an outer insulating side wall for closing the inner surfaces of said electrodes.

8. A piezo-electric crystal holder for use in a system adapted to keep the crystal at substantially constant temperature, comprising two electrodes, a piezo-electric crystal interposed between said electrodes, one of said electrodes being in the form of a relatively flat plate, the other electrode lying directly below the first mentioned electrode and having a base portion from which a support member upwardly extends for supporting the crystal, said support member having a greater exposed area than that of the fiat plate electrode so as to serve as an efficient heat conducting surface to transfer the heat from the crystal to the ambient atmosphere, an inner spacing member contained within the confines of the support member to space the electrodes apart from each other, and an outer insulating side wall for closing the inner surfaces of said electrodes.

MENDEL OSNOS.