Keyboard data entry device

Claim 2

A data entry keyboard suitable for use with data processing devices comprising: a plurality of keys supported in a relatively fixed spacial relationship, each of said keys including means for radiating an electromagnetic field whenever the key is actuated, and an electromagnetic radiation detecting means positioned proximate said keys and responsive to the radiation emanating from the said actuated key for providing unique outputs identifying the said depressed key.

Claim 3

A data entry keyboard as set forth in claim 1 in which said keys and said electromagnetic radiation detecting means are complementary and the detecting means include a unique pair of detecting elements in physical alignment with each of said keys.

Claim 4

A data entry keyboard as set forth in claim 2 in which the keys and the electromagnetic detecting means are arranged in a complementary rectangular matrix.

Claim 5

A data entry keyboard suitable for use with a data processing device comprising: a plurality of keys supported in a relatively fixed spacial relationship with freedom to move in one direction only from a first stable position to a second actuated position, means coacting with a said key when it is in the said second actuated position for supplying a high frequency current, each of said keys including means for radiating a restricted high frequency electromagnetic field, and a normally open switch means which is closed when the key is moved from the said first position to the said second position for establishing a connection between the said radiating means and the supply of high frequency current, and an electromagnetic radiation detection means positioned proximate said keys and coacting with the high frequency electromagnetic radiation from a said actuated key for providing unique outputs identifying the said actuated key.

Claim 6

A data entry keyboard suitable for use with a data processing device comprising: a plurality of keys supported in a relatively fixed spacial relationship with freedom to move in one direction only from a first stable position to a second actuated position, means coacting with a said key when it is in the said second actuated position for supplying a high frequency current, each of said keys including means for radiating a restricted high frequency electromagnetic field, and a normally open switch means which is closed when the key is moved from the said first position to the said second position for establishing a connection between the said radiating means and the supply of high frequency current, and an electromagnetic radiation detection means positioned proximate said keys and coacting with the high frequency electromagnetic radiation from a said actuated key for providing unique outputs identifying the said actuated key.

Claim 7

A data entry keyboard as set forth in claim 4 in which the means for radiating a restricted high-frequency electromagnetic field is a coil carried by a stem on the key and said coil is provided with a first termination connected to the high-frequency current supply and a second terminal connected to said normally open switch means.

Claim 8

A data entry keyboard as set forth in claim 5 in which the switch means included in the key are located within the key and comprises: a relatively fixed electrode connected to the high-frequency current supply, a moveable electrode connected to the said second terminal of the coil, and compressible means urging said fixed and moveable electrodes out of contact with each other and yielding under an actuating force to permit contact.

Claim 9

A data entry keyboard as set forth in claim 4 in which said electromagnetic radiation detection means comprises: a first group of spaced substantially parallel conductors, a second group of spaced substantially parallel conductors arranged to intersect said first group and electrically insulated therefrom at the points of intersection, a first group of differential sense amplifiers each connected to adjacent spaced conductors in said first group of conductors for providing an output whenever the current induced in the connected conductors in response to a key actuation are out of phase with each other, a second group of differential sense amplifiers each connected to adjacent spaced conductors in said second group of conductors for providing an output whenever the currents induced in the connected conductors in response to a key actuation are out of phase with each other.

Claim 10

A data entry keyboard as set forth in claim 7 further including: means responsive to said first and second groups of differential sense amplifiers for encoding the unique combinations of outputs of said first and second group of differential sense amplifiers.