RESISTIVE SWITCH MATRIX
First Claim
1. A keyboard, comprising:
- a matrix of switch sites, each site associated with a row conductor, a column conductor, and a pressure sensitive switch for enabling a conductive path between the row conductor and the column conductor; and
a printed resistance associated with each pressure sensitive switch, the resistance changing based on force applied to the switch.
2 Assignments
0 Petitions
Accused Products
Abstract
Architecture for a keyboard that supports the n-key rollover feature, while being compatible with well established, high volume, inexpensive manufacturing techniques. The design is a matrix design that uses resistors at each key rather than diodes, and employs novel circuits which allow any combination of simultaneous key presses to be detected using this resistive matrix. The resistors can be screen printed on the flexible sheets in a manner similar to the conductors. A resistive keyboard matrix employs circuit techniques that eliminate phantom key presses. The resistors can be created by screen-printing carbon ink. Additionally, various implementations of the decoder circuits can be employed to provide the n-key rollover feature on flexible sheets for inexpensive production.
85 Citations
21 Claims
-
1. A keyboard, comprising:
-
a matrix of switch sites, each site associated with a row conductor, a column conductor, and a pressure sensitive switch for enabling a conductive path between the row conductor and the column conductor; and a printed resistance associated with each pressure sensitive switch, the resistance changing based on force applied to the switch. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
-
-
11. A keyboard, comprising:
-
a matrix of pressure sensitive switch sites, each site associated with a row conductor, a column conductor, and a key that when pressed creates a conductive path between the row conductor and the column conductor; a resistance formed in association with each pressure sensitive switch site, the resistance changing based on force applied to the key; and a sensing circuit for sensing state of each pressure sensitive switch site independently, the state based on a resistance value that corresponds to the force applied to the key. - View Dependent Claims (12, 13, 14, 15, 16, 17)
-
-
18. A method of providing switch signals in a keyboard, comprising:
-
providing a matrix of pressure sensitive switch sites on a flexible substrate, each site associated with a key, a first conductor, and a second conductor, each key creating a connection between the first conductor and the second conductor when pressed; imposing a resistance in series between a first conductor and a second conductor of a pressure sensitive switch site when pressing an associated key; sensing state of the pressure sensitive switch site based on force applied to the key when pressing the key; and outputting the state as a logic level. - View Dependent Claims (19, 20, 21)
-
Specification