Patent US 3,945,482

Orthogonal ten-finger keyboards are disclosed for typewriters, computer terminals, and other devices processing alphanumeric information that maximize entry rates and stroking accuracy--and minimize finger motions and the time needed to master the keyboard. The invention employs a plurarity of vertically oriented keys adjacent to horizontal home keys. The invention places five high frequency consonants on home keys under the fingers of the right hand; the space and four high frequency vowels on home keys under the fingers of the left hand; and ten medium frequency characters on adjacent vertical keys. Two-key chords executed by fingers of the same hand generate common two-character sequences belonging to the keys stroked. The keyboard is split into rotated halves containing curved key rows and slanted key tops of variable height to follow the architecture of the hand. The invention discloses optimum orthogonal keyboards for English, German, French, Italian, Spanish, Portuguese, Swedish, and Dutch.