Sheet membrane keyboard and electronic apparatus using same

An electronic apparatus comprising:

• an exterior case adapted to contain electronic components and having a body portion of non-conductive material providing a keyboard surface outwardly disposed with respect to the interior of said case;
• said body portion of non-conductive material having a plurality of spaced depressions formed therein to extend partially through the thickness thereof, said spaced depressions opening onto said keyboard surface and respectively located at corresponding key switch positions;
• an electrically conductive layer disposed at the bottom of each of said depressions within said body portion of non-conductive material;
• a keyboard sheet including a flexible membrane of non-conductive material having opposing first and second surfaces, said first surface being disposed adjacent to and substantially covering said keyboard surface;
• an interconnection pattern including a plurality of electrical conductors disposed on said first surface of said flexible membrane facing said keyboard surface and arranged to provide a pair of electrical conductors in proximity at each of said key switch positions;
• said flexible membrane flexing in a direction toward said keyboard surface of said exterior case to move a respective pair of electrical conductors corresponding to a particular key switch position into engagement with said conductive layer disposed at the bottom of the depression located at the respective key switch position in response to pressure on said second surface of said flexible membrane selectively applied at said particular key switch position, whereby an electrical connection occurs between said respective pair of conductors via said conductive layer at the selected key switch position;
• and
• electronic circuit means disposed in said exterior case and connected to said interconnection pattern, said electronic circuit means including
• means for sensing an electrical connection between respective pairs of conductors at each of said key switch positions, and
• means for performing an electronic function and generating a result in response to sensed electrical connections between pairs of conductors corresponding to particular key switch positions.

In an electronic apparatus, a keyboard structure comprising:

• an exterior case for the electronic apparatus adapted to contain electronic components thereof and having a body portion on non-conductive material providing a keyboard surface outwardly disposed with respect to the interior of said case;
• said body portion of non-conductive material having a plurality of spaced depressions formed therein to extend partially through the thickness thereof, said spaced depressions opening onto said keyboard surface and respectively located at corresponding key switch positions;
• an electrically conductive layer disposed at the bottom of each of said depressions within said body portion of non-conductive material;
• a keyboard sheet including a flexible membrane of non-conductive material having opposing first and second surfaces, said first surface being disposed adjacent to and substantially covering said keyboard surface;
• an interconnection pattern including a plurality of electrical conductors disposed on said first surface of said flexible membrane facing said keyboard surface and arranged to prvide a pair of electrical conductors in proximity at each of said key switch positions;
• and
• said flexible membrane flexing in a direction toward said keyboard surface of said exterior case to move a respective pair of electrical conductors corresponding to a particular key switch position into engagement with said conductive layer disposed at the bottom of the depression located at the respective key switch position in response to pressure on said second surface of said flexible membrane selectively applied at said particular key switch position, whereby an electrical connection occurs between said respective pair of conductors via said conductive layer at the selected key switch position.