3D phone case is the plastic case with the lenticular sheet with image printed(need the special design for the image). As the lenticular have many small cylinder, and the refraction theory of the cylinder makes your left eye and right eye see two images from different angles at the same time, so your brain will integrate them into a 3d depth image. (The theory of flash effect is same)
What 3D lenticular effects can we make?
——3D, a lenticular effect that gives the illusion of depth, known as 3D depth
——Flip, a lenticular effect that causes two images to change back and forth
——Animation, a lenticular effect that simulates movement,known as motion
——Zoom, a lenticular effect that shows a small object gradually change
——Morph,a lenticular effect that simulates a smooth transformation from one object to another.