Popular Science artist's conception shows phone made possible by new sound lenses: 1949
Back in 1949, Bell Telephone Laboratories engineer Winston E. Kock imagined a "little black box you never have to touch – just talk and listen to." He developed lenses that direct incoming sound toward the user and away from the transmitter, making clunky handsets obsolete:
You can understand why lenses are necessary if you've ever held an old-fashioned telephone receiver near the transmitter. The transmitter picks up the receiver's sound, which keeps going around the circuit until it is a howl.
"Kock shows microwave ancestry of sound lenses by using one lens to focus both types of waves"
Kock's vision of the future didn't stop at touch-free phones. His work on artificial dielectrics preceded metamaterials by half a century, and he patented an electronic organ in 1938. He went on to become the first director of NASA's Electronics Research Center.
"Spreading high-pitched musical notes from a single speaker may be use of this lens"
"Circular sheets of perforated metal make another type of acoustic lens"
"Difference in thickness between edge and middle slows some waves more than others, making them focus at a point"
"This lens consists of metal discs on an open framework. Originally built for microwaves, it also works for sound"