Posted: October 7, 2014

Contributed by Ray Angers

Was this ever in question? After all, the introduction of the two tone flash unit on the iPhone 5s last year was universally praised for improving indoor picture quality.  In Apple’s words, the True Tone flash “variably adjusts color and intensity for over 1,000 combinations so photos taken with a flash appear more natural”.  The True Tone flash incorporated both an amber and a white LED into a pill-shaped module.  However, leaked pre-release images of the iPhone 6 showing a round flash aperture next to the camera lens lead some to speculate that Apple was returning to a single LED flash.  These rumours were invalidated when leaked component images showed that Apple had indeed developed a new round version of the True Tone flash.  The Apple community then launched into a debate on the aesthetic merits of pill-shaped versus round flash holes, but we won’t venture into that hornet’s nest.  What we’re interested in is what’s inside these flash units.

Below is what the flash modules look like after being extracted from their respective phones. The location of the white and amber LEDs is obvious.

 

With the fresnel lenses removed, we see that the structure of the LEDs is quite different.  The phosphor layers were left intact on the individual LEDs.  The LEDs found in the iPhone 5s have at least one additional component mounted to the package base besides the LED die itself (likely a protection diode).  These do not appear on the iPhone 6 flash.  X-ray images show these are encased under the white bumps of the module substrate. The active area of the light emitting chips is similar for both at approximately 1 mm2.

The X-ray images of the iPhone5s module also show a flip-chip interconnect structure on the LEDs similar to that observed on Philips LEDs that we have analyzed here in the past. While we’re confident that the LED chips found in iPhone6 are also connected to the package in a flip chip configuration, contacts have likely shrunk to the point where we can’t resolve them in these images. Philips had been rumoured to be the main supplier of iPhone flash modules in the past.  Perhaps that is no longer the case with Apple’s latest release. https://www.apple.com/ca/pr/library/2013/09/10Apple-Announces-iPhone-5s-The-Most-Forward-Thinking-Smartphone-in-the-World.html