Why does the LCD screen ripple when pressed up?

LCD liquid crystal display has a variety of arrangements, that's why there are TN screen, IPS screen and so on called. One of them that will easily produce water ripples is the TN type, which is also the principle used by most soft screens.

Imagine that the liquid crystal is a long bar, it mainly changes the tilt angle relative to the vertical direction to change the gray scale. At this point, press a certain force will change the larger value tilt angle. At this point, looking at the legendary IPS hard screen, why is he not prone to water waves? The LCD is arranged in such a way that the tilt angle relative to the horizontal direction is changed to change the gray scale. At this point, applying a certain amount of force in the vertical direction has little effect on the change in tilt angle. At the same time, the liquid crystal of this structure is much faster than TN recovery, so it is easy to recover.

It should be emphasized that this is not mainly because of the hard screen and hard glass, so it seems difficult to appear water waves when pressing the glass. However, IPS has the ability to use a hard glass screen because of the arrangement of the liquid crystal and the different direction of the electric field controlling the liquid crystal, while the TN type cannot be used.

TN LCD display principle is the upper and lower glass plate printed circuit board, can not use hard glass; IPS LCD display principle, only the lower glass is circuit control, so the upper layer can be thick, thin, hard, soft as you like.