With the case of any orientations of optical axis in uniaxial crystal,the versatile and precise formula of the phase difference for a birefringent plate is derived by means of Huygens principle.

• 在单轴晶体光轴任意取向的情形下应用惠更斯原理导出了双折射滤光片产生位相差的精确公式,结合几种熟知的特殊情形进行了简要讨论,给出完全一致的相关结果,揭示该普遍公式的正确性。