石英晶体是激光测距唯一的时间标尺, 其稳定性直接影响着测距结果的准确性。石英晶体内部水汽含量对晶体性能有着很大的影响, 分析了不同程度的内部水汽含量在不同温度下对晶体元器件的性能影响。研究表明, 水汽含量越大, 温度越接近极限, 对石英晶体的影响越严重。提出了封装前在125 ℃±5 ℃的烘箱内烘烤0.5 h后取出, 反复抽真空、充高纯氮气五个循环的方法, 可以将水汽含量可控制在≤2 000 ppm以下, 达到了降低内部水汽含量的目的。

Quartz crystal is the only time scale for laser ranging. Its stability directly affects the accuracy of ranging results. The Moisture content in quartz crystal has a great influence on the performance of crystal. The influence of different internal water vapor content on the performance of crystal devices at different temperatures is analyzed. The results show that the higher is the moisture content, the closer is the temperature to the limit, which influences on the quartz crystal seriously. Five cyclic processes are proposed such as removing moisture from the quartz crystal after baking for 0.5 hours in the baker with 125 ℃±5 ℃ before packaging, vacuuming repeatedly and refilling pure nitrogen. And the moisture content can be controlled below 2 000 ppm, and the purpose of reducing the water vapor content in the quartz crystal is achieved.