k k=123 δ=2e+ 2(2k+ k≥0.1 1)劈棱处e=0 光程差为 2劈棱处为暗纹    + = = = + =   0,1,3, 2 (2 1) 1,2,3, 2 2 k k k k e     （1）劈棱处 e = 0 光程差为: 2   = 劈棱处为暗纹