The latest iPhone 5S rumour suggest that Apple may not be able to produce enough new iPhones to meet demand due to poor yield rates of the fingerprint sensor.

LCD driver chips are also in short supply, according to DigiTimes.

As a result of the slow production of the parts, the manufacturing has been put back to July, and as a result Apple may miss the scheduled September launch, according to DigiTimes sources.

If Apple meets the September launch date it is likely that the supply of the new iPhone 5S will be limited at launch.

According to the source, three million units of the initial shipments of iPhone 5S will be delayed to the fourth quarter.

This isn't the first time that claims have appeared suggesting that Apple's iPhone 5S (or iPhone 6) will be delayed due to the fingerprint scanner. Back in April, KGI Securities analyst Ming-Chi Kuo said that Apple's planned fingerprint sensor poses multiple technical challenges that could cause delays to upcoming devices.

"Apple has to work out how to prevent interference from the black and white coating material under the cover glass," he said. "Apple is the first to attempt this function and technology, and time is needed to find the right coating material, which will likely affect iPhone 5S shipments," he said.

Then in May reports claimed that Apple's new iPhone will feature what is referred to as a "sapphire crystal touch" home button. This new touch-sensitive button covered by scratch-resistant sapphire crystal glass will replace the current home button. The sensor needs to be scratch-resistant to maintain its fingerprint sensing capabilities.

That report highlights some of the difficulties in implementing the new fingerprint technology from the high cost of the glass to the difficulty of assembling the parts, and having to avoid scratching the surface

Related:

New iPhone: Sapphire crystal fingerprint scanner 'to be embedded

iPhone 5S could be delayed by fingerprint sensor, says analyst

Apple job advert gives clues about iPhone 6 fingerprint sensor

iPhone 6 rumours: Fingerprint sensor, NFC e-wallet set to feature

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