Using unity 4.6 UI and raycast2D functionality

Hello! In my game, I have an inventory screen. I set this inventory up with some mumbo jumbo code, and now it sort of works. Problem is, I am still raycasting things that are behind my UI.

My question is quite simple: How can I get the functionality that would make it so that my raycasting would only check the UI layer when my inventory is open? I read something about layermasking, but I wanted to ask specifically about my problem here, as I am still confused on how to implement this.

Here is some of my already implemented raycast scripting:

         Ray ray = Camera.main.ScreenPointToRay(Input.mousePosition);
         RaycastHit2D hit = Physics2D.Raycast(ray.origin, ray.direction);
 
         if(canMove == true) {
             if(Physics2D.Raycast(ray.origin,ray.direction)) {
                 if(Input.GetKeyDown(KeyCode.Mouse0) && hit.collider.tag != "UnMoveable" && timeBeforeMove == 0f) {
                     if(openinventory.InventoryRestriction == false) {
                         positionHit = hit.point;
                         isMoving = true;    
                     }
                 }
             }
         }

There's still some more, but I feel it is irrelevant to the question. Please ask me if you want more information! :)