How can I have the reverse of this effect?

Firstly disclamer I am pretty new to Unity. I have a 2D topdown game where the player has a field of view radius effected by colliders. I am accomplishing this by calculating the field of view from a youtube video that I saw and by giving it a mesh renderer and giving it a semi transparent material so the area looks a little darker. The problem is that I want the field of view area to look normal while I want the rest of the map to be this darker color. How can I accomplish this?

Below is my mesh Object: