Switch arrangement
View Patent ↗A switch arrangement is disclosed. The arrangement comprises a number of switches arranged on a substrate, each switch having a resiliently deformable conductive dome for making an electrical connection with a corresponding contact on the substrate; and a number of signal lines for connection to a microprocessor for signalling an operation of a switch. The switches are arranged such that operation of any given switch creates a unique electrical connection between two of the signal lines and each of the signal lines is electrically connected to a conductive surface of a respective dome. Also disclosed is a cover for a portable electronic apparatus, having a number of user operable keys. The keys are connectable to a microprocessor in the apparatus via electrical connections made using the conductive domes.
1. A cover, for attachment to an electronic apparatus having a plurality of key domes disposed in a predetermined pattern, the cover comprising:
plurality of contacts positioned for registration with conductive key domes of the electronic apparatus;
discontinuous electrical pathways between respective ones of the plurality of contacts; and
a plurality of user accessible keys arranged such that actuation of respective ones of the plurality of keys completes the electrical pathway between respective pairs of the plurality of contacts.
2. A cover as claimed in claim 1 wherein each of the plurality of contacts is resilient and is arranged such that when the cover is attached to the electronic apparatus, the contact provides enough contact force to provide an electrical connection but not so much force that the key dome is substantially deformed.
3. A cover as claimed in claim 1 wherein the position of an individual key is independent of the position of any of one of the plurality of key domes of the electronic apparatus.
4. A cover as claimed in claim 1 wherein the cover comprises more keys than the electronic apparatus has key domes.
5. A cover as claimed in claim 1 wherein the keys are arranged for controlling an electronic game.
6. A cover as claimed in claim 1 wherein a unique key is provided for each letter of the alphabet.
7. A cover as claimed in claim 6 wherein the keys are arranged as a qwerty-style keyboard.
8. A cover as claimed in claim 1 wherein the cover is arranged to be removable by a user of the electronic apparatus.
9. A cover as claimed in claim 1 wherein the cover is a front cover.
10. A cover as claimed in claim 1 comprising a light guide for allowing light to pass through the cover from a surface of the electronic apparatus.
11. A cover as claimed in claim 1 wherein an electrical pathway is completed by a conductive part of a key short connecting two discontinuous electrical pathways.
12. A portable electronic apparatus comprising a body portion having a switch arrangement comprising:
a plurality of switches arranged on a substrate, each switch comprising a resiliently deformable conductive dome for making an electrical connection with a corresponding contact on the substrate;
and a plurality of signal lines for connection to a microprocessor for signaling an operation of a switch,
wherein the switches are arranged such that operation of any given switch creates a unique electrical connection between two of the plurality of signal lines and each of the plurality of signal lines is electrically connected to a conductive surface of a respective dome and a cover as claimed in claim 1 .
13. A portable radio telephone comprising: a body portion having a plurality of switches, each switch comprising a resiliently deformable conductive dome; and a removable cover comprising means for attachment to the body portion and for co-operation with the domes and comprising a plurality of user operable keys, wherein the relative positions of the keys on the cover are independent of the relative positions of the domes.
14. A removable cover for attachment to the portable radio telephone as claimed in claim 13 .