Re: Could anybody explain...
Human hearing has approx 130 dB of dynamic range. Microphones with good audio quality at this kind of range are expensive, and too large to mount in a mobile phone.
A compromise (used by just about everyone else) is to use a less sensitive microphone, with 100 dB of range, but this means that loud sounds will cause it to distort. Alternatively, it can be mechanically damped so that it will not distort at high volumes, but then you lose the ability to detect softer sounds because the microphone diaphragm is now too resistant to movement.
Nokia's idea was to use two mics, one damped one for high level sounds, and another undamped one for lower level, and use some clever signal processing to mix these dynamically. A different version of the technology uses one diaphragm (with, I suspect, a non-linear amplitude response), and better signal processing to re-form the sound signal afterwards.
It is clever, and it does work. That's why they got the patent. But this isn't about patents... HTC didn't use the method to make their own part; it seems that their supplier, STElectronics, supplied HTC with the *exact* part that they were making on Nokia's behalf. That's not patent infringement, it's breach of contract and possibly theft (STE were making these for Nokia, and Nokia alone, so the components were not STE's to give to HTC).