According to a report in The China Times (Translated by computing.co.uk), sources in the Apple supply chain claim that, "Apple intends to switch to alternative touch technology for its next generation of mobile phones, stating that a 'Touch On Display' panel is being developed by Taiwanese Apple supplier Innolux."
In November, game developers at CMA Megacorp in London identified a glitch with rapid diagonal scrolling on the iPhone 5. They tweeted that if you "slide [your] finger back and forth diagonally on screen, input events drop out or stop altogether." The video above demonstrates the glitch by testing this kind of action on two iPhone 4 units, one running iOS 5 and the other iOS 6 against two iPhone 5 units with the same two versions of iOS. In both of the iPhone 5s, the screen froze up after a bunch of touch events piled up, but not on the iPhone 4s.
User comments I have read suggest that not all of the new iPhones are equally sensitive, and then only for users, like Fruit Ninja or Infinity Blade players, who routinely make this kind of diagonal swiping action on their phones.
Cult of Mac reported in September that the iPhone 5s thin "in cell" combination of touch screen and LCD display in one, was "causing 'significant production constraints' that mean Apple cannot produce the device fast enough." It may be that quality control has been a significant issue.
iPhone 6 could include new touch technology (Computing)
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