The iPhone 6 is expected to be unveiled by Apple on September 9th. / Reuters

Reuters reports that the company has been unhappy with the quality of the backlights in the new iPhone, causing disruptions down the supply chain

Apple is widely expected to unveil the new iPhone 6 next month, but a new report of supply chain disruption suggests that fans will have to wait a while before getting their hands on one.

Reuters reports that Apple’s desire to continue slimming down their devices has forced the company to redesign the phone’s backlighting after the original screen was found to be insufficiently bright.

It’s widely expected that Apple will announced two new iPhones on September 9, offering users the choice of a 4.7-inch and 5.5-inch model – both of which are larger than the current 4-inch screens on the iPhone 5S and 5C.

The phones’ displays are also rumoured to be a much-tougher glass-sapphire mix, and the new devices will also run the latest version of Apple’s mobile operating system – iOS 8.

Apple’s new smartphones, which are announced on a regular, yearly cycle, usually go on sale around 10 days after their unveiling, and even without disruption in the supply chain they tend to sell out fairly quickly.

The addition of a new screen size (primarily aimed at attracting fans of larger, phablet-sized phones in the Asian Pacific region) could also help prime demand, and Apple’s stock has hit new highs in expectation, clearing $100 earlier this week.