The U.S. Patent and Trademark Office granted Apple's ornamental design patent claim which shows a single line drawing of the floating microphone surrounded by a bezeled circle, and describes the property as the "front view of a display screen or portion thereof" showing the new design.
Apple designer Freddy Anzures and user interface designer Alessandro Francesco Sabatelli are credited as the icon's inventors, with the patent application first filed on Oct. 4, 2011, the same day that Siri was unveiled alongside the iPhone 4.
Apple's website refers to the icon in its Siri FAQ webpage:
The microphone icon lights up to let you know that Siri hears you talking. Once you?ve started a dialogue with Siri, tap the microphone icon to talk to it again.
The design itself is reminiscent of the distinctive ribbon-type microphones made by RCA in the 1940's, which were subsequently copied by various audio product makers like Crown.
Vintage RCA Type 77-DX microphone. | Source: Los Angeles Guitar Shop
Although still technically a beta product, Apple's Siri virtual assistant is one of the most well-known pieces of voice-recognizing technology seen on a modern consumer device. First debuted as the standout feature of the iPhone 4S, Siri is now available on the iPhone 5, the third and fourth-generation iPad, the iPad mini and the fifth-generation iPod touch.