Browse Prior Art Database

Universal Keyboard Assembly

IP.com Disclosure Number: IPCOM000050369D
Original Publication Date: 1982-Oct-01
Included in the Prior Art Database: 2005-Feb-10
Document File: 2 page(s) / 45K

Publishing Venue

IBM

Related People

Nassimbene, EG: AUTHOR

Abstract

This keyboard assembly is designed to accommodate either capacitor-matrix or cross-point matrix "contact" elements. The keys each have a conductive plate, preferably of magnetic metal, and a small boss projecting below the plate. In a cross-point matrix switch, the boss is pressed onto the switch at a given cross-point location to depress normally spaced conductors together, while in a capacitance type switch the boss is used to bottom out the key travel for establishing a predetermined capacitance at each "switchpoint".

This text was extracted from a PDF file.
At least one non-text object (such as an image or picture) has been suppressed.
This is the abbreviated version, containing approximately 56% of the total text.

Page 1 of 2

Universal Keyboard Assembly

This keyboard assembly is designed to accommodate either capacitor-matrix or cross-point matrix "contact" elements. The keys each have a conductive plate, preferably of magnetic metal, and a small boss projecting below the plate. In a cross-point matrix switch, the boss is pressed onto the switch at a given cross-point location to depress normally spaced conductors together, while in a capacitance type switch the boss is used to bottom out the key travel for establishing a predetermined capacitance at each "switchpoint".

As shown in the drawing, the upper part of the keyboard assembly is the same for either type of switch assembly; the lower part differs mainly in the type of switch assembly that is planned.

For the capacitance switch assembly, the lower part comprises a base circuit board 12 basically having a plurality of conductive plates 14 each having a central aperture 16 therein, with the plates fixed in position on the board 12.

For the cross-point switch, an elastomeric switch body 20, for example, is laid on a base plate 22. The body 20 comprises at least a lower conductor 24 running generally across the body and upper conductors 26',26,26'', and so on, all spaced from the lower conductor by a sheet of insulating material 28 having apertures 30 at the desired cross-points.

The upper part of the keyboard is interchangeable with respect to the lower part. A support structure 36 carries a number of retaining members 38, for reta...