Electroluminescent display device

Claim 2

A display device comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connecting rows to columns at their crossover points; a voltage source, the voltage level of which is sufficient to initially cause luminescence in a cell; means for cyclically connecting a selected column in circuit with said voltage source at a fixed frequency; and means for cyclically connecting a selected row and all nonselected columns in circuit with said voltage source at said fixed frequency shifted in phase so as to minimize luminescence of non-selected cells.

Claim 3

The display device according to claim 1 wherein said voltage source is a two terminal source, one terminal of which is connected to one end of said column and row conductors, and the other terminal of which is connected to each of said means for cyclically connecting.

Claim 4

The display matrix according to claim 1 wherein said electroluminescent cells are comprised of an insulating envelope containing an ionizable medium, and at least one pair of insulated electrodes positioned for ionizing the medium when a voltage level commensurate with the ionization voltage of said medium is applied across a pair of electrodes, such that the ionization of said medium causes a wall charge to be attached to the interior wall surfaces of said insulating envelope.

Claim 5

The display device according to claim 1 wherein said means for cyclically connecting are operated at a fixed frequency which is sufficiently high so as to prevent visual detection of flicker in the selected electroluminescent cell.

Claim 6

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a two terminal voltage source, one terminal of which is connected to a common point; a first bank of switches for individually connecting each row conductor alternately between the common point and the other terminal of said voltage source; a second bank of switches for individually connecting each column conductor alternately between the common point and the other terminal of said voltage source; means for providing two phase clock signals; means for alternating a selected switch in said second bank in response to said clock signal of one phase, while alternating all non-selected switches in said second bank in response to said clock signal of a second phase; means for alternating a selected switch in said first bank in response to said clock signal of second phase, while maintaining all non-selected switches in said first bank connected to the other terminal of said voltage source, so as to cause the electroluminescent cell connected between the selected row and column to luminesce as alternate potentials are applied across said cell, while minimizing the luminescence of non-selected cells.

Claim 7

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a two terminal voltage source, one terminal of which is connected to a common point; a first bank of switches for individually connecting each row conductor alternately between the common point and the other terminal of said voltage source; a second bank of switches for individually connecting each column conductor alternately between the common point and the other terminal of said voltage source; means for providing two phase clock signals; means for alternating a selected switch in said second bank in response to said clock signal of one phase, while alternating all non-selected switches in said second bank in response to said clock signal of a second phase; means for alternating a selected switch in said first bank in response to said clock signal of second phase, while maintaining all non-selected switches in said first bank connected to the other terminal of said voltage source, so as to cause the electroluminescent cell connected between the selected row and column to luminesce as alternate potentials are applied across said cell, while minimizing the luminescence of non-selected cells.

Claim 8

The display matrix according to claim 5 wherein said electroluminescent cellS are comprised of an insulating envelope containing an ionizable medium, at least one pair of insulated electrodes positioned for ionizing the medium when a voltage level commensurate with the ionization voltage of said medium is applied across a pair of electrodes, such that the ionization of said medium causes a wall charge to be attached to the interior wall surfaces of said insulating envelope.

Claim 9

The display device according to claim 5 wherein the frequency of the two phase clock signal is sufficiently high so as to prevent visual detection of flicker in the selected electroluminescent cell.

Claim 10

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a voltage source for providing a voltage level commensurate with the ignition voltage of said cells; impedance means connecting said voltage source to one end of each of said row and column conductors; a first bank of switches for individually connecting each of said row conductors in circuit with said voltage source; a second bank of switches for individually connecting each of said column conductors in circuit with said voltage source; a two phase signal source; means for applying one phase of said two phase signal to each switch in said second bank, to alternately close and open each switch at the signal frequency; means for applying the one phase of said two phase signal to the selected switch of said first bank of switches; and means for disconnecting the one phase signal from the selected switch in said second bank of switches, and for connecting the other phase signal to the selected switch so as to cause said electroluminescent cell connected between the selected row and column to be alternately connected in circuit with said voltage source causing said electroluminescent cell to alternately ignite for every alternation of the selected switches.

Claim 11

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a voltage source for providing a voltage level commensurate with the ignition voltage of said cells; impedance means connecting said voltage source to one end of each of said row and column conductors; a first bank of switches for individually connecting each of said row conductors in circuit with said voltage source; a second bank of switches for individually connecting each of said column conductors in circuit with said voltage source; a two phase signal source; means for applying one phase of said two phase signal to each switch in said second bank, to alternately close and open each switch at the signal frequency; means for applying the one phase of said two phase signal to the selected switch of said first bank of switches; and means for disconnecting the one phase signal from the selected switch in said second bank of switches, and for connecting the other phase signal to the selected switch so as to cause said electroluminescent cell connected between the selected row and column to be alternately connected in circuit with said voltage source causing said electroluminescent cell to alternately ignite for every alternation of the selected switches.

Claim 12

The electroluminescent display matrix according to claim 8 wherein said electroluminescent cells are comprised of an insulating envelope containing an ionizable medium, and at least one pair of insulated electrodes positioned for ionizing the medium when a voltage level commensurate with the ionization voltage of said medium is applied across a pair of electrodes, such that the ionization of said medium causes a wall charge to be attached to the interior wall surfaces of said insulating envelope.

Claim 13

The display matrix according to claim 8 wherein the frequency of the two phase signal is selected such that alternate ignitions of the electroluminescent cells appear continuous to the human eye.

Claim 14

A display device comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connecting rows to columns at their crossover points; a voltage source, the voltage level of which is sufficient to initially cause luminescence in a cell; means for cyclically connecting a selected column in circuit with said voltage source at a fixed frequency while connecting all non-selected columns to a reference potential; and means for cyclically connecting a selected row in circuit with said voltage source at said fixed frequency shifted in phase while connecting all non-selected rows to said voltage source, so as to minimize luminescence of non-selected cells.

Claim 15

A display device comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connecting rows to columns at their crossover points; a voltage source, the voltage level of which is sufficient to initially cause luminescence in a cell; means for cyclically connecting a selected column in circuit with said voltage source at a fixed frequency while connecting all non-selected columns to a reference potential; and means for cyclically connecting a selected row in circuit with said voltage source at said fixed frequency shifted in phase while connecting all non-selected rows to said voltage source, so as to minimize luminescence of non-selected cells.

Claim 16

The display matrix according to claim 11 wherein said electroluminescent cells are comprised of an insulating envelope containing an ionizable medium, and at least one pair of insulated electrodes positioned for ionizing the medium when a voltage level commensurate with the ionization voltage of said medium is applied across a pair of electrodes, such that the ionization of said medium cauSes a wall charge to be attached to the interior wall surfaces of said insulating envelope.

Claim 17

The display device according to claim 11 wherein said means for cyclically connecting are operated at a fixed frequency which is sufficiently high so as to prevent visual detection of flicker in the selected electroluminescent cell.

Claim 18

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a two terminal voltage source, one terminal of which is connected to a common point; a first bank of switches for individually connecting each row conductor alternately between the common point and the other terminal of said voltage source; a second bank of switches for individually connecting each column conductor alternately between the common point and the other terminal of said voltage source; means for providing two phase clock signals; means for alternating a selected switch in said second bank in response to said clock signal of one phase while maintaining all non-selected switches in said second bank connected to said common point; and means for alternating a selected switch in said first bank in response to said clock signal of second phase while maintaining all non-selected switches in said first bank connected to the other terminal of said voltage source so as to cause the electroluminescent cell connected between the selected row and column to luminesce as alternate potentials are applied across said cell, while minimizing the luminescence of non-selected cells.

Claim 19

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a two terminal voltage source, one terminal of which is connected to a common point; a first bank of switches for individually connecting each row conductor alternately between the common point and the other terminal of said voltage source; a second bank of switches for individually connecting each column conductor alternately between the common point and the other terminal of said voltage source; means for providing two phase clock signals; means for alternating a selected switch in said second bank in response to said clock signal of one phase while maintaining all non-selected switches in said second bank connected to said common point; and means for alternating a selected switch in said first bank in response to said clock signal of second phase while maintaining all non-selected switches in said first bank connected to the other terminal of said voltage source so as to cause the electroluminescent cell connected between the selected row and column to luminesce as alternate potentials are applied across said cell, while minimizing the luminescence of non-selected cells.

Claim 20

The electroluminescent display matrix according to claim 14 wherein said electroluminescent cells are comprised of an insulating envelope containing an ionizable medium, and at least one pair of insulated electrodes positioned for ionizing the medium when a voltage level commensurate with the ionization voltage of said medium is applied across a pair of electrodes such that the ionization of said medium causes a wall charge to be attached to the interior wall surfaces of said insulating envelope.

Claim 21

The electroluminescent display matrix according to claim 14 wherein the frequency of said two phase clock signals is sufficiently high so as to prevent visual detection of flicker in the selected electroluminescent cell.

Claim 22

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a two terminal voltage source, one terminal of which is connected to a common point; impedance means connecting the other terminal of said voltage source to one end of each of said row and column conductors; a first bank of switches for individually connecting the opposite end of each of said row conductors to the common point; a second bank of switches for individually connecting the opposite end of said column conductors to the common point; means for providing two phase clock signals; means for alternately closing a selected switch in said second bank in response to said clock signal of one phase while maintaining all non-selected switches in said second bank in the closed position; and means for alternately closing a selected switch in said first bank in response to said clock signal of other phase while maintaining all non-selected switches in said first bank in the opened positions.

Claim 23

An electroluminescent display matrix comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of electroluminescent cells connected between the crossings of row and column conductors; a two terminal voltage source, one terminal of which is connected to a common point; impedance means connecting the other terminal of said voltage source to one end of each of said row and column conductors; a first bank of switches for individually connecting the opposite end of each of said row conductors to the common point; a second bank of switches for individually connecting the opposite end of said column conductors to the common point; means for providing two phase clock signals; means for alternately closing a selected switch in said second bank in response to said clock signal of one phase while maintaining all non-selected switches in said second bank in the closed position; and means for alternately closing a selected switch in said first bank in response to said clock signal of other phase while maintaining all non-selected switches in said first bank in the opened positions.

Claim 24

The electroluminescent display matrix according to claim 17 wherein said electroluminescent cells are comprised of an insulating envelope containing an ionizable medium, and at least one pair of insulated electrodes positioned for ionizing the medium when a voltage level commensurate with thE ionization voltage of said medium is applied across a pair of electrodes, such that the ionization of said medium causes a wall charge to be attached to the interior wall surfaces of said insulating envelope.

Claim 25

The display matrix according to claim 17 wherein the frequency of the two phase signal is selected such that alternate ignitions of the electroluminescent cells appear continuous to the human eye.

Claim 26

A display device comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of bistable display elements connecting rows to columns at their crossover points; a first pulsating voltage source the voltage level of which is sufficient to cause said bistable display element to change state; a second pulsating voltage source of the voltage level of which is sufficient to cause said bistable display elements to change state,said second source being out of phase with said first source; means for connecting a selected column to said first pulsating voltage source; and means for connecting a selected row and all non-selected columns to said second pulsating voltage source.

Claim 27

A display device comprising in combination: a plurality of row conductors; a plurality of column conductors forming a matrix with said plurality of row conductors; a plurality of bistable display elements connecting rows to columns at their crossover points; a first pulsating voltage source the voltage level of which is sufficient to cause said bistable display element to change state; a second pulsating voltage source of the voltage level of which is sufficient to cause said bistable display elements to change state,said second source being out of phase with said first source; means for connecting a selected column to said first pulsating voltage source; and means for connecting a selected row and all non-selected columns to said second pulsating voltage source.