温度对长焦距测量精度的影响

 基于Ronchi光栅的泰伯效应，在理论上分析了温度场的波动对长焦距测量系统稳定性的影响。通过大量实验研究验证了在长焦距测量系统中内部和外部温度场的波动引起空气折射率的随机变化，进而影响到测量系统焦距测量值的稳定性。在对测量系统He-Ne激光源采取水循环降温、切断系统外部冷热源、对测量系统中光栅对采取隔热封装等有效措施后，使长焦距测量系统的重复性测量精度提高了5～8倍，标准差达到了0.1‰左右，测量数据波动范围在5 mm左右，其测量精度及其稳定性均达到了实际测量的要求。

Effect of temperature on measuring system of long focal length

On the basis of Talbot effect of Ronchi grating,the influence of temperature on the stability of the measuring system of long focal length has been theoretically analyzed.It has been testified by experiment that the fluctuation of refractive index of atmosphere resulted from the interior and exterior temperature of the system influences the measuring precision.After taking some methods such as reducing the surface-temperature of He-Ne laser in the measuring system by water-circulation,removing the cold and heat source of the exterior,putting the couple-grating into heat insulation,the repeatability precision of the measuring system increases by 5 to 8 times.Standard error of 0.1‰ is achieved,and data fluctuation of repetitive measurement is within 5mm.