Camera - Resize 3d plane to iphone screen size

I hope someone will answer my question. im using orthographic projection camera with size 6.5. Camera captured the view and show into a 3d plane but the size is not right (scale for 3d plane is 1,1,1) but if i resize into (just say) 480,1,640 the view is blurry not focus.

Im ising this script and it worked views camera into 3d plane

WebCamTexture back;
void Start ()
{
back = new WbCamTexture ();
renderer.material.mainTexture = back;
back.Play ();

What i want is i need my 3d plane auto scale into camera view size (iphone 6+) Please help

the correct world size is orthographic size times 2 for height and another times aspect ratio for the with. if it is blurry after that, the resulting of the rendertexture is wrong.