Flexible printed circuit for split keyboard and method of assembly

DETAILED DESCRIPTION OF A PRESENTLY PREFERRED EXEMPLARY EMBODIMENT The present invention solves the problem of connecting a circuit through a hinge in a way that contains and protects the circuit, minimizes the size of a hinge, and eliminates multiple circuit boards and connectors.
Printed circuits are commonly used in portable instruments that, because of size limitations, comprise multiple components that are folded with respect to each other when in a closed position, and then opened to an operable position.
The present invention uses a flexible printed circuit member that is folded in such as way as to allow more electrical traces, or leads, per volume through the hinge than in previous designs, and in such a way that the interconnecting portion of the flexible circuit fits wholly within a tightly compacted hinge.
As shown in FIGS.
1 and 2, a keypad assembly 10 embodying the present invention, has a first keypad portion 12 mounted in a first housing 14 and a second keypad portion 16 mounted in a second housing 18.
In the illustrated exemplary embodiment, the keypad assembly 10 is adapted for use as a foldable keyboard in a relatively small and compact data entry, storage and/or retrieval device, such as a telecommunication instrument having keypad input capability.
Each of the keypad portions 12, 16 have a plurality of keys 20 that, in the illustrated exemplary embodiment, are arranged in a standard keyboard layout, with the left half of the standard keyboard layout being disposed in the first keypad portion 12, and the right half of the standard keypad layout being disposed in the second keypad portion 16 of the keypad assembly 10.
Desirably, the first and second housings 14, 18, comprise an upper portion through which the keys 20 extend, and a lower portion into which the upper portion is assembled by snap engagement or other retention means.
As shown in FIGS.
1-5, each of the housings 14, 18, are coplanarly disposed with respect to each other and pivotally interconnected together for rotation about an axis 22 that is perpendicular to the planar disposition of the housings 14, 18