So long as we just cover a half of the biprism with a straight edge of untransparent plate, the interference fringes disappear and the straight edge diffraction fattern produced by the biprism ridge displaies on the screen.

• 只要用一不透明的直边屏,恰好挡住半个双棱镜时,则干涉条纹消失,在屏幕上就呈现出由棱脊产生的直边衍射花样了。