There has been a range of Apple patents relating to head-mounted displays over the past year and this particular one shows that the company put some serious effort into researching this product category.
The patent describes "peripheral treatment for head-mounted displays," which specifically refers to video playback in a device such as glasses worn by a user. The idea is to use a peripheral light resembling the changing color tone of a video playing on the frame to virtually eliminate the frame from the field of view.
Interestingly, the idea dates back to October 2006 when the patent was filed, which was about the same time frame Philips made a final push to market with its "Ambilight" LCD TVs. These emitted wall illumination behind the frame that matched the colors displayed on the screen and gave the impression that the screen was much bigger than it really was.
Of course, we have not heard much about Ambilight since then and even less about Apple's ambient light glasses. It's unclear whether there is still interest in such a product, but it is worth noting that one of the two inventors credited in the patent is Tony Fadell, the creator of the iPod. Fadell has moved on since then and works as founder and CEO of thermostat maker Nest today.
Google's Project Glass is somewhat different, as Google is pitching an augmented reality device, while the Apple device hints that Apple was or still is working on a content viewing device.