History of hearing aids
The development of transistors in 1948 by Bell Laboratories led to major improvements to the hearing aid. The transistor was invented by John Bardeen, Walter Brattain, and William Shockley. Transistors were created to replace vacuum tubes; they were small, required less battery power and had less distortion and heat than their predecessor. These vacuum tubes were typically hot and fragile, so the transistor was the ideal replacement.The 1952 Sonotone 1010 used a transistor stage along with vacuum tubes, to extend battery life. The size of these transistors led to developments in miniature, carbon microphones. These microphones could be mounted on various items, even eyeglasses. In 1951, Raytheon manufactured the transistor and was one of the first companies to mass-produce transistors to throughout America. Raytheon realized that their hearing aid only lasted short-term and began to sell the vacuum-tube hearing aids again along with transistor hearing aids.
Ian Munro Ross
In 1952 William Shockley hired him to work in semiconductors at Bell Labs, and he arrived in Murray Hill just after John Bardeen and Walter Houser Brattain had left. Shockley's group focused exclusively on transistor improvements, and Ross and G. C. Dacey were instrumental in the early stages of development of the field-effect transistor. In 1960 Ross and others invented epitaxy. He subsequently rose through managerial ranks, ultimately serving as the sixth President of Bell Labs 1979–1991 and overseeing its reorganization following the breakup of the Bell System.