Hard OLED, Soft OLED and In-Cell Difference ?
We illustrate the differences that characterize the various displays. This speech is purely related only to the displays for iPhone X or higher (such as iPhone XS, 11 Pro, 12 etc.).
Hard OLED
What most differentiates Hard OLED displays are the optimal color rendering comparable to the original and a higher brightness. But this model has a more rigid panel, this can more easily lead to a breakage resulting from accidental impacts. Pay attention, I did not say that it is fragile and that it will surely break but that it is more delicate than the more expensive Soft OLED model.
Recapping:
Soft OLED
Unlike the model just described, the panel of a Soft OLED display is thinner, and this together with greater flexibility allow you to absorb more shocks and greatly reduce the risk of breakage and failure.
Recapping:
In-Cell
As for the In-Cell displays, they present as the original the touch module and the LCD (which has the function of displaying images) on the same layer of the panel. In this way the touch and therefore its sensitivity will be optimal, reactive, more pleasant and fluid. This is combined with a lower weight and thickness making it more compact and similar to the original (for example after assembly, observing the iphone sideways we will notice that the thickness will be the same as the original one). The only model among the most recent that mounts this technology is the iPhone 11, as from the X model onwards they are all OLEDs.