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AssigneeTexas Instruments Incorporated
InventorsPietro De Filippis, Amedeo Salvatore, Luigi Abbondandolo
Estimating the term…
A keyboard unit is shown having a substrate in which portions of the substrate are physically displaced to provide a cavity, an embossment and a plurality of protuberances for each switching station. The embossment, in registry with a button contact area, projects upwardly from the floor of the cavity a selected distance with a discontinuous annulus contact area extending around its respective cavity in generally the same plane as that in which the top surface of the substrate lies. The cavity includes a channel shaped portion extending through the discontinued portion of the discontinuous annulus. The protuberances project upwardly from the general plane of the substrate's top surface and serve to laterally locate a snap-acting disc over the contact areas. The disc may be selectively coated with highly electrically conductive material to optimize electrical switching. A piece of flexible, electrically insulative sheet may be placed over the unit to seal it from the environment.
A method of making a low profile keyboard in which a snap-acting disc is employed as a switching element between contact areas at each of a plurality of microswitches comprising the steps of selecting a substrate having a generally flat top and bottom planar surface and having an electrically insulative surface thereon, for each microswitch forming a first electrically conductive contact area on the surface, forming a second electrically conductive contact area on the surface spaced from each first contact area, punching the substrate so that a plurality of protuberances extending above the flat top surface are formed spaced around each microswitch to maintain a disc at a selected location relative to the contact areas, a respective depression being formed in the bottom surface aligned with each protuberance.
Dependencies are inferred from the claim text.