Tuning fork-type quartz crystal oscillator and method for stabilizing the vibration frequency thereof

Abstract

A method for stabilizing the vibration frequency of an oscillator which contains a tuning fork-type quartz crystal element comprising a pair of arms each having a given size and a common connecting section connecting the mutually facing ends of the paired arms. The method comprises bonding the common connecting section of the quartz crystal element directly to a base member supporting the same by an appropriate adhesive agent, sensing the amount of vibration energy leaking from the crystal element into the base member while causing the paired crystal arms to be mechanically vibrated in the opposite directions, and minimizing the leaking vibration energy by repeatedly adjusting each size of the paired crystal arms, thereby enabling the subject quartz crystal oscillator not only to minimize the amount of vibration energy leaking to the outside therefrom but also present excellent resistance to external mechanical vibrations and shocks, and consequently maintaining the vibration frequency of the crystal oscillator at the highest possible precision and stability for a long period of time.

What is claimed is: 
     
       1. A method for stabilizing the vibration frequency of an oscillator which contains a tuning fork-type quartz crystal element comprising a pair of arms having mutually facing ends, each arm having a given size, and a common connecting section connecting the mutually facing ends of the paired arms, the method comprising:   bonding only substantially the whole bottom surface of the common connecting section of said tuning fork-type quartz crystal element directly to a base member supporting the same by an adhesive agent;   mechanically vibrating the paired quartz crystal arms and sensing the amount of vibration energy leaking from the common connecting section of said quartz crystal element into the base member while the paired quartz crystal arms are mechanically vibrating; and   minimizing said leaking vibration energy by repeatedly adjusting the sizes of the paired quartz crystal arms.   
     
     
       2. A method claimed in claim 1 wherein a pair of crystal electrodes are provided on the periphery of said quartz crystal element and a pair of external electrodes are attached to the base member, comprising connecting the paired crystal electrodes of said quartz crystal element by an electroconductive adhesive agent to the paired external electrodes. 
     
     
       3. A method claimed in claim 2 comprising fabricating at least that surface portion of the base member on which said quartz crystal element is disposed of electroconductive material, and connecting said electroconductive surface portion of the base member as one of the paired external electrodes. .Iadd. 4. A method claimed in claim 1 comprising adding material to at least one of said paired arms prior to mechanically vibrating said arms; and wherein said adjusting step comprises removing at least part of said added material to minimize said leaking vibration energy. .Iaddend. .Iadd. 5. In a tuning fork-type quartz crystal element comprising a pair of arms having mutually facing ends and respective free ends, each arm having a given size, and a common connecting section connecting the mutually facing ends of the paired arms; the improvement wherein:   only substantially the whole bottom surface of the common connecting section of said tuning fork-type quartz crystal element is bonded directly to a base member supporting the same by an adhesive agent; and   the lengths of the paired quartz crystal arms being selectively cut down at their free end portions such that the amount of vibration energy leaking from the common connecting section of said quartz crystal element into the base member while the paired quartz crystal arms are mechanically   
     
     
        vibrating is minimized. .Iaddend. .Iadd. 6.  The tuning fork-type quartz crystal element of claim 5, comprising a pair of crystal electrodes connected on the periphery of said quartz crystal element by an electroconductive adhesive agent; and a pair of external electrodes attached to the base member. .Iaddend..Iadd. 7. The tuning fork-type quartz crystal element of claim 6 wherein at least that surface portion of the base member on which said quartz crystal element is disposed is made of electrodconductive material, and said electroconductive surface portion of the base member is connected as one of the pair of external electrodes. .Iaddend. .Iadd. 8. The tuning fork-type quartz crystal element of claim 5 wherein at least one of the paired quartz crystal arms comprises a material added thereto, said added material comprising portions from which a part of said added material has been removed to minimize said leaking vibration energy. .Iaddend. .Iadd. 9. A tuning fork-type quartz crystal element comprising a pair of arms having mutually facing ends and a common connecting section connecting the mutually facing ends of the paired arms, manufactured by the process of: bonding only substantially the whole bottom of the common connecting section of said tuning fork-type quartz crystal element directly to a base member supporting the same by an adhesive agent;   mechanically vibrating the paired quartz crystal arms and sensing the amount of vibration energy leaking from the common connecting section of said quartz crystal element into the base member while the paired quartz crystal arms are mechanically vibrating; and   minimizing said leaking vibration energy by repeatedly adjusting the sizes of the paired quartz crystals arms. .Iaddend. .Iadd. 10. A tuning fork-type quartz crystal element as defined by claim 9 wherein a pair of crystal electrodes are provided on the periphery of said quartz crystal element and a pair of external electrodes are attached to the base member, the paired crystal electrodes of said quartz crystal element being connected to the paired external electrodes by an electroconductive adhesive agent. .Iaddend..Iadd. 11. A tuning fork-type quartz crystal element according to claim 10 wherein at least that surface portion of the base member on which said quartz crystal element is disposed is made of electroconductive material, and said electroconductive surface portion of said base member is connected as one of the paired electrodes. .Iaddend..Iadd. 12. A tuning fork-type quartz crystal element according to claim 9 wherein the sizes of the paired quartz crystal arms are adjusted by adding material to at least one of said paired arms prior to mechanically vibrating said arms, and removing at least part of said added material to minimize said leaking vibration energy. .Iaddend. .Iadd. 13. A tuning fork-type quartz crystal element according to claim 9 wherein said sizes of the paired quartz crystal arms are adjusted by cutting off end portions thereof to minimize said leaking vibration energy. .Iaddend..Iadd. 14. A tuning fork-type quartz crystal element according to claim 9 wherein said sizes of the paired quartz crystal arms are adjusted by adding material thereto to minimize said leaking vibration energy. .Iaddend.