Membrane Keyboards and Human Performance

Abstract

Membrane switch technology has become increasingly popular in many consumer-oriented products due to its low production cost and design flexibility. However, the absence of familiar key travel associated with membrane switches removes an important, direct source of feedback to the user with respect to specific keystrokes. Hence, the conventional wisdom has been that membrane switches without key travel are unacceptable for keyboard applications such as typing tasks.

This paper describes systematic human factors research in which typing performance using a commercially available membrane keyboard and a conventional, full-travel keyboard was compared for subjects representing different levels of typing proficiency. Each subject (N = 21) used a membrane keyboard for 3 consecutive (or nearly consecutive) days and a conventional keyboard for 3 consecutive (or nearly consecutive) days. Each day of experience consisted of a one-hour session in which various typing exercises were completed. Traditional tests of typing performance were administered at the beginning and end of each session.

The results indicate that for non-touch typists there was little difference in performance between keyboards. For touch typists performance with the conventional keyboard was initially much better than that with the membrane keyboard. There was, however, rapid learning with the membrane keyboard such that, within a few sessions, the difference in typing performance between the conventional and membrane keyboards was reduced substantially. There remained some advantage for the conventional keyboard, compared with the membrane keyboard evaluated here. Future work will be aimed at measurement of the additional improvement in performance resulting from extended practice with better-designed membrane keyboards.