According to KGI Securities analyst Ming-Chi Kuo, is Apple working on a sapphire covered convex home button with a fingerprint sensor for the next iPhone, the iPhone 5S. That analyst has a quite good track record, so this could be true.
But will a convex home button really be good? Yes sapphire is very hard and scratch proof but every time you lay the iPhone with the front down, the iPhone will jiggle a bit, I guess.
And is a fingerprint sensor really something we want? Is that enough to make the iPhone exciting again?
Convex home button creates space for fingerprint sensor; yield to improve. We think that a fingerprint sensor will be placed under the home button of iPhone 5S. However, assembling it could be difficult as the space under home button is limited as it already has to accommodate the Lightning connector, speaker and microphone. Thus, we think the shape of the home button could be changed from concave to convex to create more space for a fingerprint sensor.
Sapphire prevents home button from being scratched. A convex home button could be more easily scratched, so a harder material is required. We believe Apple will switch from plastic to sapphire, whose hardness is second only to diamond. Sapphire would protect the home button from being scratched and the fingerprint sensor from being damaged.