The Model F was a series of computer keyboards produced mainly from 1981–1985 and in reduced volume until 1994 by IBM and later Lexmark. Its mechanical-key design consisted of a buckling spring over a capacitive PCB, similar to the later Model M keyboard that used a membrane in place of the PCB.
Model F capacitive pads from an opened assembly
Corrosion occurring on a Model F 122 terminal keyboard along with dust
A comparison between a Model F spring (left) and a Model M spring (right); the Model M uses a spring with fewer windings and smaller plate for the plastic membrane underneath.
Image: IBM Model F 122 key Keyboard
A computer keyboard is a peripheral input device modeled after the typewriter keyboard which uses an arrangement of buttons or keys to act as mechanical levers or electronic switches. Replacing early punched cards and paper tape technology, interaction via teleprinter-style keyboards have been the main input method for computers since the 1970s, supplemented by the computer mouse since the 1980s.
A wired computer keyboard for desktop use manufactured by Lenovo
Keyboards on laptops usually have a shorter travel distance and a reduced set of keys.
Multifunction keyboard with LCD function keys
A Greek keyboard lets the user type in both Greek and the Latin alphabet (MacBook Pro).
