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US 5,514,842 AGranted
Keyboard circuit apparatus
AssigneeFujitsu Limited
InventorsTakeshi Sugii, Yoshiaki Ohashi
Life of this patent
Estimating the term…
Abstract
A keyboard circuit apparatus is constituted such that resistive elements are provided both in a first sheet and a second sheet, an insulating spacer being laid on the first sheet, and the second sheet being laid on the insulating spacer. When a key switch is closed, one of the resistive elements provided on the first sheet and one of the resistive elements provided on the second sheet are electrically connected in series so that a desired value of resistance can be obtained.
Claims32
A keyboard circuit apparatus comprising:
- a first sheet produced such that a plurality of X lines, first resistive elements connected to the respective X lines and first contacts provided at the ends of said respective first resistive elements are printed on a first sheet main body;
- a second sheet produced such that a plurality of Y lines are crossed by said X lines, a plurality of second resistive elements connected to the respective Y lines and second contacts provided at the ends of said respective second resistive elements are printed on a second sheet main body;
- and
- an insulating spacer having a plurality of openings,
- wherein said insulating spacer is laid on said first sheet and said second sheet is laid on said insulating spacer so that said first contacts and said second contacts are directly opposite each other respectively at said openings, and
- any one of said first resistive elements and the corresponding one of said second resistive elements are electrically connected in series when the corresponding one of said first contacts and the corresponding one of said second contacts are brought into contact with each other.
3 more elements
A keyboard circuit apparatus comprising:
- a first sheet which includes:
- a plurality of X lines, each X line having a plurality of corresponding resistive elements, each resistive element having a first end connected to the corresponding X line and a second end having a contact point thereon;
- a second sheet which includes:
- a plurality of Y lines, each Y line having a plurality of corresponding resistive elements, each resistive element having a first end connected to the corresponding Y line and a second end having a contact point thereon, the contact points on the second ends of the resistive elements of the Y lines respectively corresponding to the contact points on the second ends of the resistive elements of the X lines to define a plurality of pairs of contact points;
- and
- an insulating spacer layer positioned between the first sheet and the second sheet and having a plurality of openings respectively corresponding to the plurality of pairs of contact points, wherein
- the X lines of the first sheet extend in a first direction and the Y lines of the second sheet extend in a second direction which crosses the first direction,
- the corresponding contact points in each pair of contact points are positioned directly opposite to each other with the corresponding opening of the insulating spacer layer therebetween, and
- contact through the corresponding opening between the contact points of a respective pair of contact points causes the resistive elements of the contacting contact points to be electrically connected in series.
6 more elements
Dependencies are inferred from the claim text.