Timeline of events

New information may get added here occasionally.

1962	Earliest discovered advertised photoelectric encoder keyboard, Invac’s PK-144 (patent filed in 1961)
1968	Hall effect keyboards introduced by Micro Switch as SW Series Earliest known full-travel membrane keyboards, Datanetics batch-fabricated array
1969	First large scale production of Datanetics batch-fabricated array keyboards
1970	Earliest known matrix scan keyboards
1971	Earliest discovered advertisement for an off-the-shelf single-chip encoder, for General Instrument’s AY-5-2376
1977	Earliest discovered “intelligent” (microprocessor encoder) keyboards, IMSAI’s IKB-1 and Micro Switch SD Series model 103SD24-1
1983	Cherry MX introduced, one of very few historic switch types still in production