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Stress0 l+ H7 }, X3 ^7 P. [
Quartz crystals will change frequency when stress is applied. This stress can come from any or all of several sources. Package and mounts, epoxy connection, metal films, and the quartz itself can be sources of stress. If the stress is constant over the life of the part, frequency will stay constant. However, in the real world, stresses relax with time hence, stress related aging occurs.
$ S% s* S' d% D+ x+ k! S
& @0 V4 H! v6 VEpoxy
$ j+ b+ {! x6 i( m! r4 I, AConductive epoxy or glue is used to make electrical connection to the package. During cure, the epoxy shrinks and puts stress on the quartz through the joint. Softer epoxies and silicon can be used to reduce this effect. However, the epoxy (due to outgassing) is a significant source of potential contamination." ]0 e2 B3 d' C7 @; L {# V
9 ^; L) Y( I' D6 ^. U- S- O這裡講的是封裝過程使用環氧樹脂（Epoxy），但其產生的應力，仍是有可能破壞到晶振的結構。. m/ _. B0 d) a; t. q
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附註：
% G/ [& k. {9 L% \+ r) ooutgassing 洩氣
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发表于 2017-7-13 17:07
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发表于 2017-7-17 15:32
