This is a trademark filing, not a patent. True Tone is the dual LED flash on the back side of the iPhone 5s. One LED is amber, one white. From Apple’s web site:

The new True Tone flash gives the iSight camera capabilities that are the first for any smartphone. It’s made up of two LEDs, one white and one amber. But they don’t simply fire in tandem. When you take a picture with the flash enabled, the iSight camera uses software algorithms to assess the color temperature of the scene. That allows iPhone 5s to determine just the right percentage and intensity of white light versus amber light you need — using over 1000 unique combinations. The result is a beautiful shot with more true-to-life colors. Not too cool. Not too warm. Better highlights. More natural-looking skin tones. And the same goes for the iSight videos you record.

With all the new tech associated with the release of the iPhone 5s and 5c, I somehow missed this. I definitely see the difference in my pictures, though. I love the tone I get when shooting with my 5s.