Keyboard switch - has assembly of contact points at upper and lower plates with layers of two adhesives which bond at temps. slightly higher than room temp.

摘要

The switch for a keyboard is formed by placing an upper contact point at one side of an upper plate and a lower contact point on a side of a lower plate, with an insulating layer round the lower contact. One adhesive is developed which has no adhesion at room temp., but has an adhesive property at a temp. moderately above room temp., but below the melting point of the upper and lower plates. A second adhesive is also used which has no adhesion at room temp., but sticks at the moderately raised temp. A layer of the first adhesive is applied between one side of the upper plate and the insulating layer, to surround the first contact point without covering it. A further adhesive layer, from the second adhesive, is between the other side of the lower plate and the stiffening plate below it. The components are assembled to bring together the stiffening plate, and the lower plate and the upper plate so that the upper and lower contact face each other, with the insulting layer and the first adhesive layer between the upper and lower plates, and the second adhesive layer is between the lower plate and the stiffening plates. The stiffening plate, and the upper and lower plates are pressed together together with moderate heat to bond the upper and lower plates together and the lower plate with the stiffening plate so that, when pressure is applied to the upper contact it meets the lower contact. USE/ADVANTAGE - The switch is for input and function keys, and the like, to operate electronic appts. such as audio-video and word processing systems. The technique give high technology standards for a keyboard, and the like, with densely packed and miniaturised switching units, with an effective operation.