Apple has invited members of the media to attend a Sept. 10 event, promising to "brighten everyone's day" as competitors scramble to avoid being overshadowed.

Though the rainbow-hued bubbles on the invitation echo the previously disclosed design theme of Apple's forthcoming mobile operating system, iOS 7, the primary focus of the event is expected to be the successor to Apple's iPhone 5, and a lower-priced iPhone model intended to appeal to customers in developing markets.

iOS 7 also is likely to receive attention because it has received a major design overhaul.

Faced with vigorous competition from Android handset makers like Samsung -- already being sued by Apple for copying the iPhone -- Apple's recent ads have focused on its product design as a primary point of differentiation.

[ Google isn't sitting idly by. Read about its new mobile OS: Google's Next Android Called 'KitKat'. ]

Whether design matters as much to phone buyers as it does to Apple remains to be seen. But the Android camp has wasted no time in trying to undercut Apple's pitch: Google's pre-emptive Android 4.4 "KitKat" marketing partnership with Hershey's has arrived with a parody of Apple's celebration of its design prowess.

Samsung, too, is attempting to get out in front of what's likely to be wall-to-wall iPhone coverage next week by announcing its $299 Galaxy Gear smartwatch and its Galaxy Note 10.1 tablet. Apple is believed to be working on a smartwatch of its own for release in 2014.

Market research firm Panjiva predicts that Apple's event also will feature a new version of Apple TV, the company's streaming media peripheral. Google earlier this summer launched a streaming media peripheral of its own, Chromecast, to challenge Apple's growing presence in consumers' living rooms.

Although Apple also is working on an update to its desktop operating system, OS X Mavericks, and a completely redesigned Mac Pro, the company is likely to introduce those products this fall separately from the iPhone event.

Apple's event will be held at 10 a.m. Pacific Time in Cupertino, Calif., at Apple's corporate headquarters, with follow-up events planned for Beijing, Berlin and Tokyo.

The Beijing event suggests Apple might have finally struck an iPhone deal with China Mobile, China's largest mobile carrier. If that's the case, Apple will gain access to some 700 million new potential customers, and CEO Tim Cook, under pressure to return Apple's stock to the stratospheric valuation it reached a year ago, will be golden once again.

Even if Apple hasn't come to an agreement with China Mobile, the company's ongoing good fortune is magnified by the woes facing Microsoft. In a gambit to save Windows Phone from irrelevance and to revitalize its new strategic vision, Microsoft last week announced CEO Steve Ballmer's impending departure and this week said it plans to spend $7.2 billion to buy Nokia's Devices & Services business and to license Nokia's patents and mapping services.

Even if Apple stumbled -- if its new iPhone failed to amaze and iOS 7 was received with the same coolness as Windows 8 -- it would have time to correct its course. But given Apple's track record, it's far more likely the company will darken the day for competitors.