Browse Prior Art Database

Low Profile Magnetic Keyboard

IP.com Disclosure Number: IPCOM000041371D
Original Publication Date: 1984-Jan-01
Included in the Prior Art Database: 2005-Feb-02
Document File: 3 page(s) / 51K

Publishing Venue

IBM

Related People

Bolda, FJ: AUTHOR [+3]

Abstract

Fig. 1 illustrates in a schematic cross section an enlarged view of a single key position in a multiple key keyboard. The components are essentially stamped, die-cut sections of continuous sheets of material that are stacked together. The main components depicted create a magnetic snap-actuation mechanism that may be employed with any of a variety of sensor technologies well known in the art. The main baseplate 1 consists of a continuous plastic magnetic material or the like with a number of apertures 11, one for each key position. A circuit board 2 that can be integral with the magnetic material 1, as in a printed circuit, on top of it or which may be separately applied to a circuit board 2, is also included.

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Low Profile Magnetic Keyboard

Fig. 1 illustrates in a schematic cross section an enlarged view of a single key position in a multiple key keyboard. The components are essentially stamped, die-cut sections of continuous sheets of material that are stacked together. The main components depicted create a magnetic snap-actuation mechanism that may be employed with any of a variety of sensor technologies well known in the art. The main baseplate 1 consists of a continuous plastic magnetic material or the like with a number of apertures 11, one for each key position. A circuit board 2 that can be integral with the magnetic material 1, as in a printed circuit, on top of it or which may be separately applied to a circuit board 2, is also included. On the circuit board 2 or in the circuitry incorporated on the surface of magnet 1 will be the conductive lines and logic circuits necessary for operation as a keyboard. The leads 3 are thus schematic and show that electrical signals can be supplied to and from circuit board 2. Element 4 is a tongue or flap of steel or similar ferro magnetic substance which has been die cut from a continuous sheet of flexible steel stock. The leaf or tongue portion 4 is normally attracted toward magnet 1 and lies in tight conformance to the surface of the circuitry on the circuit board 2. Capacitive actuation is thus clearly envisioned, but electrical contact between the tongue 4 and/or cooperating contacts on the circuit board 2 are also possible, as are a variety of other electronic sensing schemes well known in keyboard arts. The upper surface of magnet 1 contacts, but is usually electrically insulated from, a similar steel flexible non-magnetic (phosphor-bronze, spring brass) actuator which has a stamped-out flap or tongue section that is formed to include a tongue 5 and a downward-projecting lip 8 which contacts the surface of tongue 4 through the aperture 11. An overlying sheet 7 serves as a contamination shield and nomenclature sheet on which may be printed the indicia representative of the key mechanism beneath. A base frame 9 has a plurality of apertures or compartments 10 to permit deflection of the tongue portion 5 and to support the circuit board 2 and the apparatus above it, as shown in Fig. 1. Fig. 2 illustrates the cross-sectional view through an overall assembled keyboard with multiple key positions. It may be readily seen that the base pan or framework could be molded plastic or the like and that multiple layers for the circuit board 2, the magnet sheet 1 and the overlying actuator sheet 6 as well as the aperture tongue or flap sheet 4 could all be stacked in their appropriate relationship and held...