KEYPAD AND KEYPAD MODULE

摘要

The keypad has a plurality of pressure-sensitive key regions (10), each key region (10) being assigned a light-guiding structure (12) and each structure (12) being assigned a light source (24) for feeding a light and an optical receiver (26) for receiving light. The light-guiding structures (12) are covered by a common covering (6) having high inherent stiffness with the interposition of an elastic support (14). The light-guiding structures (12) are fitted on a common carrier plate, such that, when pressure is exerted on a key region (10) the covering (6) is pressed against the support (14) and the latter is pressed against the light-guiding structure (12), such that a light propagating in the light-guiding structure (12) is disturbed and this disturbance is evaluated as a touch signal. Owing to the use of a stiff covering (6), only extremely small key strokes in the submillimetre range occur when the key region is actuated. In order to ensure reliable functioning of the keypad, a means for tolerance compensation of height differences of the installation positions of the light-guiding structures (12) is provided according to the invention. This is preferably a curable composition which is applied in the viscous state before the application of the covering (6) and subsequently cures.