Good step in adding subpixel matrix commentary. However, are you sure the display is RGGB (two greens per) and not RG/BG (one green, alternating red and blue)? RGGB is not common (if it does exist) but is what an incorrectly oriented subpixel photo can imply. The image shown here is ambiguous between the two, and it's in effect worse to misconfirm it as RGGB (a full matrix with redundancy) if it is in fact RG/BG (an incomplete matrix).
Make sure you align the device properly on the microscope. You need to align the device so that the horizontal and vertical directions are represented correctly in the figure. Then with that, take heed that diagonal dots => RG/BG, and horizontal/vertical dots => RGGB.
You're well on your way.