US2004170A

US2004170A - Crystal holder

Info

Publication number: US2004170A
Application number: US710036A
Authority: US
Inventors: Moser Wilhelm; Leng Leopold
Original assignee: Telefunken AG
Current assignee: Telefunken AG
Priority date: 1933-02-06
Filing date: 1934-02-06
Publication date: 1935-06-11
Anticipated expiration: 1952-06-11

Description

June 11, 1935. w MOSER r AL 2,004,170

CRYSTAL HOLDER Filed Feb. 6. 1934 XNVENTORS WILHELM MOSER Y LEO POLDZENG 7kg MW ATTORNEY Patented June 11, 1935 UNITED STATES PATENT OFFICE CRYSTAL HOLDER Application February 6, 1934, Serial No. 710,036 In Germany February 6, 1933 4 Claims.

This invention relates to an arrangement for crystal oscillators comprising a thermostat.

It is known from the prior art of thermostats combined with crystals that the crystal and electrodes together with means for the production of heat (heater winding) and means for the indication and regulation of the temperature (indicator winding, bimetal-strip type of switch, or the like) may be confined in an exhaust space or vessel. But it has been found that the materials used for insulation are liable to give off gases with the result that the vacuum is impaired. Another fact is that the exchange of heat between the heater winding or the indicator winding and the electrodes is impeded.

In order to obviate these drawbacks, in crystal thermostats in vacuo the source furnishing the heat and optionally also the means controlling the temperature are disposed outside the vacuous space according to this invention. For instance, all auxiliary windings for heating and temperature indication are accommodated in the interior of a metallic electrode, the electrode being so fused together with the wall of the glass vessel enveloping the vacuum that no gas-evolving insulators will be in contact with the vacuum.

Inasmuch as the space available for the electrodes is very limited, and since direct action between the heater winding and the indicator winding tends to reduce the accuracy of indication, arrangements, according to another object of the invention, may be also so chosen that the heat is applied to the electrodes by remote heating. This could be accomplished, for instance, by irradiation from a thermal radiator or by means of action from a generator which sets up eddy-currents in the electrodes.

The control of the thermal source can be effected by alternate connection and disconnection by the agency of the temperature indicator (such as a contact thermometer) embedded in the electrode, or else by the aid of a balanced resistance used as a temperature indicator action may be brought upon a bridge arrangement in which instance regulation is continuous.

Two embodiments of the invention are shown by way of example in the attached drawing. Referring to Fig. 1, I is the crystal which is disposed in the exhaust glass vessel 2 between

electrodes

3 and 4 without making contact therewith. The supporting is insured most preferably between points or tips 5 which engage the quartz crystal plate at three points about its median plane. The bottom electrode 4 is hollow and contains the heater winding 6 and a bimetal-strip switch 1 in the circuit of the heating winding.

8 denote the terminals for the crystal electrodes.

The exemplified embodiment shown in Fig. 2 differs from the one before described by that the heating winding 6 is disposed outside the electrodes. It is fed from an alternating current source 9 with interposition of the bimetal switch I and it insures the heating of the electrodes by means of eddy-current heating.

We claim:

1. A piezo electric crystal holder comprising an oscillation crystal disposed in a vacuum chamber, an upper and lower electrode for said crystal and located within said chamber, at least one of said electrodes having an aperture, a heater winding within said aperture, and a bimetallic strip within said aperture, said bimetallic strip having contacts for controlling a current supply circuit for said heater winding.

2. A piezo electric crystal holder comprising an oscillation crystal disposed in a vacuum chamber, an upper and lower electrode for said crystal and located within said chamber, at least one of said electrodes having an aperture, a bimetallic strip within said aperture, and a heater winding surrounding the outside of said chamber, said bimetallic strip having contacts for controlling the current supply for said heater winding.

3. A piezo electric crystal holder comprising an oscillation crystal disposed in a vacuum chamber, an upper and lower electrode for said crystal and located within said chamber, at least one of said electrodes having an aperture, a bimetallic strip within said aperture, and a heater winding located outside of said chamber at a position which surrounds said electrode so as to insure the heating of said electrode by means of eddycurrent heating, said bimetallic strip having contacts for controlling the current supply circuit for said heater winding.

4. A piezo electric crystal holder comprising an oscillation crystal disposed in a vacuum chamber, an upper electrode having a ring-like portion surrounding said crystal, a lower electrode having a ring-like portion surrounding said crystal, said lower electrode having an aperture which is brought outside of said chamber, a bimetallic strip within said aperture, and a heater winding located outside of said chamber at a position which surrounds said electrode so as to insure the heating of said electrode by means of eddy-current heating, said bimetallic strip having contacts for controlling the current supply circuit for said heater winding.

WILHELM MOSER. LEOPOLD LENG.