Here's the easiest way in my opinion. All o3DSs are TN screen. If you have an o3DS to compare to, it will be easy. If the n3DS screen looks the same as an o3DS from an angle, then it's TN. If you can easily see the images on the screen and the screen looks less washed out, it's IPS. The bottom screen looks a little fuzzy compared to the top, but when compared to the bottom screen on an o3DS it's easy to tell if you have IPS. Worked for me the first time I bought a n3DS. Change the theme to black for best contrast.