Predicting a diffraction pattern without the limiting assumption

[cosgriffc]

Hello all. I have a relatively simple question. I have learned very recently about wave optics and the resulting diffraction patterns. The experiment by Thomas Young was used to explain the topic and the equations were solved with the assumption that L >> d >> lambda. I was curious how one would determine a pattern without this assumption as it was never discussed in class and all the pages I find online explain the equations using this assumption.

 

[Bill_K]

cosgriffc, Diffraction using the assumption L >> d is called Fraunhofer diffraction. Otherwise without this assumption its called Fresnel diffraction.