visible light - What happens if separation between slits is greater than separation between slits and screen in YDSE experiment?

I was studying Young's double slit experiment (YDSE) in which it was derived that the formula for path difference ($\delta x$) is :

$$\delta x = \frac{y \cdot d}{D}$$ Where $y$ is the vertical position of the point where interference occurs, $d$ is the separation between the slits and $D$ is the distance between the slits and the screen.

This formula was derived under the condition that $\lambda << d << D$ (note that $\lambda$ is the wavelength of the light used).

Now my doubt is what happens if $d > D$ ? I had tried searching for answers but couldn't find any.

Thanks !