Multi-position character display panel

Claim 2

A gas-filled display device comprising an envelope consisting of a base plate and a top cover plate having a viewing window, said base plate and top plate being hermetically sealed together to form said envelope, said envelope containing a filling of an ionizable gas capable of supporting cathode glow, said platEs being spaced apart a distance of about 20 to 25 mils, a plurality of groups of cathode electrodes spaced apart along and supported on the surface of said base plate, said cathode electrodes being generally flat and coplanar, and an anode electrode associated with each of said groups of cathode electrodes, each anode being spaced from and positioned generally parallel to its group of cathode electrodes, each anode electrode comprising a thin, transparent film on the lower surface of said top plate, each anode being a few Angstroms thich and thus so thin that it is substantially coplanar with said lower surface, each anode electrode being closer to its associated group of cathode electrodes than to an adjacent group of cathode electrodes, each anode electrode and its group of cathode electrodes comprising a character position, the gas-filled space between said anodes and said groups of cathodes being free of any obstructions extending into said space from either said base plate or cover plate along the length of the panel between character positions, each anode being spaced from its group of cathodes a distance of about 10 to 25 mils and from the adjacent group of cathodes by about 30 to 40 mils.

Claim 3

The device defined in claim 1 and including an insulating layer covering said cathodes and formed with apertures overlaying said cathodes and defining the shape of said cathodes.

Claim 4

The device defined in claim 2 wherein each cathode has a larger area than its associated aperture in said insulating layer.

Claim 5

A gas-filled display device comprising an envelope consisting of a base plate and a top cover plate having a viewing window, and sealed together containing a gas filling capable of sustaining cathode glow, a plurality of conductive runs on the top surface of said base plate, an insulating layer on said runs and having a plurality of groups of apertures, each aperture exposing one of said runs, a plurality of groups of cathode electrodes spaced apart along the surface of said base plate, said cathode electrodes being generally flat and coplanar, each cathode being in contact with one of said runs through the associated aperture in said insulating layer, corresponding cathodes in each group being in contact with the same conductive run, an anode electrode associated with each of said groups of cathode electrodes, each anode being spaced from and positioned generally parallel to its group of cathode electrodes, each anode electrode comprising a thin, transparent film on the lower surface of said top plate, each anode being so thin that it is substantially coplanar with said lower surface, each anode electrode being closer to its associated group of cathode electrodes than to an adjacent group of cathode electrodes, each anode being spaced from its group of cathodes a distance of about 20 to 25 mils and from the adjacent group of cathodes by about 30 to 40 mils.

Claim 6

A gas-filled display device comprising an envelope consisting of a base plate and a top cover plate having a viewing window, and sealed together containing a gas filling capable of sustaining cathode glow, a plurality of conductive runs on the top surface of said base plate, an insulating layer on said runs and having a plurality of groups of apertures, each aperture exposing one of said runs, a plurality of groups of cathode electrodes spaced apart along the surface of said base plate, said cathode electrodes being generally flat and coplanar, each cathode being in contact with one of said runs through the associated aperture in said insulating layer, corresponding cathodes in each group being in contact with the same conductive run, an anode electrode associated with each of said groups of cathode electrodes, each anode being spaced from and positioned generally parallel to its group of cathode electrodes, each anode electrode comprising a thin, transparent film on the lower surface of said top plate, each anode being so thin that it is substantially coplanar with said lower surface, each anode electrode being closer to its associated group of cathode electrodes than to an adjacent group of cathode electrodes, each anode being spaced from its group of cathodes a distance of about 20 to 25 mils and from the adjacent group of cathodes by about 30 to 40 mils.

Claim 7

A gas-filled display device comprising an envelope consisting of a base plate and a top cover plate having a viewing window, and sealed together containing a gas filling capable of sustaining cathode glow, a plurality of conductive runs on the top surface of said base plate, a first insulating layer on said runs and having a plurality of groups of apertures, each aperture exposing one of said runs, a plurality of groups of cathode electrodes spaced apart along the surface of said base plate and supported on said first insulating layer, said cathode electrodes being generally flat and coplanar, each cathode being in contact with one of said runs through the associated aperture in said insulating layer, corresponding cathodes in each group being in contact with the same conductive run, a second insulating layer disposed on said first insulating layer and including apertures in each of which one of said cathode electrodes is positioned, an anode electrode associated with each of said groups of cathode electrodes, each anode being spaced from and positioned generally parallel to its group of cathode electrodes, each anode electrode comprising a thin, transparent film on the lower surface of said top plate, each anode being a few Angstroms thick and thus so thin that it is substantially coplanar with said lower surface, each anode electrode being closer to its associated group of cathode electrodes than to an adjacent group of cathode electrodes.

Claim 8

A gas-filled display device comprising an envelope consisting of a base plate and a top cover plate having a viewing window, and sealed together containing a gas filling capable of sustaining cathode glow, a plurality of conductive runs on the top surface of said base plate, a first insulating layer on said runs and having a plurality of groups of apertures, each aperture exposing one of said runs, a plurality of groups of cathode electrodes spaced apart along the surface of said base plate and supported on said first insulating layer, said cathode electrodes being generally flat and coplanar, each cathode being in contact with one of said runs through the associated aperture in said insulating layer, corresponding cathodes in each group being in contact with the same conductive run, a second insulating layer disposed on said first insulating layer and including apertures in each of which one of said cathode electrodes is positioned, an anode electrode associated with each of said groups of cathode electrodes, each anode being spaced from and positioned generally parallel to its group of cathode electrodes, each anode electrode comprising a thin, transparent film on the lower surface of said top plate, each anode being a few Angstroms thick and thus so thin that it is substantially coplanar with said lower surface, each anode electrode being closer to its associated group of cathode electrodes than to an adjacent group of cathode electrodes.

Claim 9

The device defined in claim 5 wherein said second insulating layer is a separate sheet set in place on said first-named insulating layer.

Claim 10

The device defined in claim 5 wherein said second insulating layer is a layer screened on said first-named insulating layer.

Claim 11

The device defined in claim 5 wherein the apertures in said second insulating layer are larger in area than said cathode electrodes.

Claim 12

The device defined in claim 5 wherein said second insulating layer embeds, completely covers, and intimately engages the edges of said cathode electrodes.

Claim 13

The device defined in claim 5 wherein said second insulating layer is thicker than said cathode electrodes, and its top surface is closer to said face plate than said cathodes.

Claim 14

The device defined in claim 5 wherein said anode electrodes are seated on said second insulating layer.

Claim 15

The device defined in claim 5 wherein each anode covers an area comparable to the area defined by each group of conductive members.

Claim 16

The device defined in claim 5 and including a conductive shield member disposed between each group of cathode electrodes.

Claim 17

The device defined in claim 5 wherein each conductive shield member includes apertures to permit equalization of gas pressure along said groups of cathode electrodes.

Claim 18

The device defined in claim 14 wherein said shield members are electrically connected to each other.

Claim 19

The device defined in claim 5 wherein said cathode electrodes comprise generally elongated, rectangular-shaped members having generally parallel end and side edges, and said second insulating layer covers said cathodes and intimately follows and engages the surface thereof including the edges thereof, said second insulating layer having apertures exposing the central generally flat portion of each cathode lying between the edges and ends thereof whereby only a flat cathode surface and no sharp edges thereof are exposed to the associated anode.

Claim 20

The device defined in claim 5 wherein said cathode electrodes comprise masses of screen-printed material including particles of conductive material which are in intimate engagement with said conductive runs.

Claim 21

The device defined in claim 5 wherein said cathode electrodes comprise metal strips secured through conductive cement to said conductive runs.

Claim 22

The device defined in claim 5 wherein said cathode electrodes comprise strips of metal deposited by a plating process in said apertures in said first insulating layer.

Claim 23

The device defined in claim 5 wherein said conductive strips, said first and second insulating layers, and said cathode electrodes comprise bodies of material formed by a screen-printing process.

Claim 24

A display device comprising a gas-filled envelope including an insulating base plate having a top surface, a plurality of conductive strips on said top surface of said base plate, an insulating layer on said strips, a plurality of spaced-apart groups of apertures in said insulating layer, each aperture in each group exposing one conductive strip, corresponding apertures in each group exposing the same conductive strip, a conductive member in each of said apertures in direct contact with the associated conductive strip and operable as a glow cathode, there thus being a group of conductive members associated with each group of apertures, a second apertured insulating layer seated on said first insulating layer and having a plurality of apertures, each enclosing one of said conductive members and shielding said conductive members from each other, an anode electrode associated with each group of conductive members, and an insulating cover plate having a viewing window through which glowing cathodes can be viewed, said base plate and said cover plate being hermetically sealed together and forming said envelope.

Claim 25

A display device comprising a gas-filled envelope including an insulating base plate having a top surface, a plurality of conductive strips on said top surface of said base plate, an insulating layer on said strips, a plurality of spaced-apart groups of apertures in said insulating layer, each aperture in each group exposing one conductive strip, corresponding apertures in each group exposing the same conductive strip, a conductive member in each of said apertures in direct contact with the associated conductive strip and operable as a glow cathode, there thus being a group of conductive members associated with each group of apertures, a second apertured insulating layer seated on said first insulating layer and having a plurality of apertures, each enclosing one of said conductive members and shielding said conductive members from each other, an anode electrode associated with each group of conductive members, and an insulating cover plate having a viewing window through which glowing cathodes can be viewed, said base plate and said cover plate being hermetically sealed together and forming said envelope.

Claim 26

A display device comprising a sealed envelope having a viewing window and containing an ionizable gas at a pressure capable of sustaining cathode glow including a first insulating sheet-like member, a plurality of groups of cathode segments, said groups being disposed side-by-side along the front surface of said first sheet-like member, conductive means for selectively energizing different combinations of cathode segments of each of said cathode segment groups to display different characters side-by-side in a substantially common plane along the length of said sheet-like member, said conductive means comprising a plurality of conductive strips extending along the back surface of said sheet-like member at least over the area covered by said cathode segment groups, a plurality of groups of apertures in said sheet-like member, the apertures of each group being aligned with one of said conductive strips and each aperture of the group being substantially aligned with a corresponding cathode segment of each cathode segment group, with the corresponding cathode segment being in electrical contact with the conductive strip, a second insulating sheet-like member adjacent to said first sheet-like member and having a plurality of apertures in each of which one of said cathode segments is positioned, and a plurality of anode electrodes each associated with one of said cathode segment groups.

Claim 27

A display device comprising a sealed envelope having a viewing window and containing an ionizable gas at a pressure capable of sustaining cathode glow including a first insulating sheet-like member, a plurality of groups of cathode segments, said groups being disposed side-by-side along the front surface of said first sheet-like member, conductive means for selectively energizing different combinations of cathode segments of each of said cathode segment groups to display different characters side-by-side in a substantially common plane along the length of said sheet-like member, said conductive means comprising a plurality of conductive strips extending along the back surface of said sheet-like member at least over the area covered by said cathode segment groups, a plurality of groups of apertures in said sheet-like member, the apertures of each group being aligned with one of said conductive strips and each aperture of the group being substantially aligned with a corresponding cathode segment of each cathode segment group, with the corresponding cathode segment being in electrical contact with the conductive strip, a second insulating sheet-like member adjacent to said first sheet-like member and having a plurality of apertures in each of which one of said cathode segments is positioned, and a plurality of anode electrodes each associated with one of said cathode segment groups.

Claim 28

A display device comprising a gas-filled envelope including an insulating base plate having a top surface, a plurality of conductive strips on said top surface of said base plate, an insulating layer on said strips, a plurality of groups of apertures in said layer, the apertures in each group being aligned in a pattern, there being correspondingly positioned and shaped apertures in each group, the same corresponding aperture in each group being aligned with and exposing the same conductive strip, a conductive member in each of said apertures in direct contact with the associated conductive strip and operable as a glow cathode in the gas in said envelope, there thus being a group of conductive members, a second insulating layer having a plurality of apertures, each enclosing one of said conductive members and shielding each in its group from conductive members of another group, an anode electrode associated with the conductive members in said apertures, and a glass cover plate through which glowing cathodes can be viewed, said base plate and said cover plate being hermetically sealed together to form said envelope.

Claim 29

A display device comprising a gas-filled envelope including an insulating base plate having a top surface, a plurality of conductive strips on said top surface of said base plate, an insulating layer on said strips, a plurality of groups of apertures in said layer, the apertures in each group being aligned in a pattern, there being correspondingly positioned and shaped apertures in each group, the same corresponding aperture in each group being aligned with and exposing the same conductive strip, a conductive member in each of said apertures in direct contact with the associated conductive strip and operable as a glow cathode in the gas in said envelope, there thus being a group of conductive members, a second insulating layer having a plurality of apertures, each enclosing one of said conductive members and shielding each in its group from conductive members of another group, an anode electrode associated with the conductive members in said apertures, and a glass cover plate through which glowing cathodes can be viewed, said base plate and said cover plate being hermetically sealed together to form said envelope.

Claim 30

A flat display panel for displaying any one of a predetermined number of characters in each of a plurality of side-by-side character positions, comprising a gas-tight envelope formed of front and base plates closely spaced to one another and sealed together along a predetermined perimeter surrounding the character positions, the front and base plates forming the outside walls of the envelope, an ionizable gas within said envelope at a pressure capable of sustaining glow discharge, at least the portions of the front plate which are aligned with the character positions being transparent to glow within the envelope to provide a viewing window for the characters to be displayed, an assembly supported within the envelope on the base plate portion thereof including a plurality of conductive runs on said base plate, a layer of insulating material on said conductive runs, and a plurality of groups of cathode electrodes aligned side-by-side on said insulating layer, with each such group forming onE of said character positions, each such conductive run being electrically connected through said insulating layer to a cathode electrode in each of said cathode groups, so that selective combinations of said cathode electrodes in each such group can be energized to provide a multi-character display, said conductive runs extending substantially parallel to one another along the length of said cathode electrode groups, and continuing along the surface of said base plate beyond said groups to the sealed perimeter, and through said sealed perimeter to the exterior of said envelope to provide external electrical connections to said cathode electrodes, and a plurality of anode electrodes, each positioned in operative relation with one of said cathode electrode groups and having a conductive lead extending through said envelope, said anode electrodes comprising thin transparent conductive films formed on the inner surface of said front plate, and each anode overlaying its group of cathode electrodes and spaced therefrom by a distance of the order of 20 to 25 mils, each anode electrode also being spaced a distance of the order of 30 to 40 mils from each adjacent group of cathode electrodes.

Claim 31

A flat display panel for displaying any one of a predetermined number of characters in each of a plurality of side-by-side character positions, comprising a gas-tight envelope formed of front and base plates closely spaced to one another and sealed together along a predetermined perimeter surrounding the character positions, the front and base plates forming the outside walls of the envelope, an ionizable gas within said envelope at a pressure capable of sustaining glow discharge, at least the portions of the front plate which are aligned with the character positions being transparent to glow within the envelope to provide a viewing window for the characters to be displayed, an assembly supported within the envelope on the base plate portion thereof including a plurality of conductive runs on said base plate, a layer of insulating material on said conductive runs, and a plurality of groups of cathode electrodes aligned side-by-side on said insulating layer, with each such group forming onE of said character positions, each such conductive run being electrically connected through said insulating layer to a cathode electrode in each of said cathode groups, so that selective combinations of said cathode electrodes in each such group can be energized to provide a multi-character display, said conductive runs extending substantially parallel to one another along the length of said cathode electrode groups, and continuing along the surface of said base plate beyond said groups to the sealed perimeter, and through said sealed perimeter to the exterior of said envelope to provide external electrical connections to said cathode electrodes, and a plurality of anode electrodes, each positioned in operative relation with one of said cathode electrode groups and having a conductive lead extending through said envelope, said anode electrodes comprising thin transparent conductive films formed on the inner surface of said front plate, and each anode overlaying its group of cathode electrodes and spaced therefrom by a distance of the order of 20 to 25 mils, each anode electrode also being spaced a distance of the order of 30 to 40 mils from each adjacent group of cathode electrodes.

Claim 32

A flat display panel for displaying any one of a predetermined number of characters in each of a plurality of side-by-side character positions, comprising a gas-tight envelope formed of front and base plates closely spaced to one another and sealed together along a predetermined perimeter surrounding the character positions, the front and base plates forming outside walls of the envelope, an ionizable gas within said envelope at a pressure capable of sustaining glow discharge, at least the portions of the front plate which are aligned with the character positions being transparent to glow within the envelope to provide a viewing window for the characters to be displayed, a plurality of conductive runs extending along and supported on the interior surface of the base plate in the direction of the side-by-side character positions, a plurality of groups of cathode electrodes positioned side-by-side along said interior surface in said direction, each such group forming one of said character positions and each cathode electrode being in the general shape of a segment of a character to be displayed, each such conductive run being electrically connected to a cathode electrode in each of said cathode electrode groups, so that selective combinations of cathode electrodes in each such group can be energized by a selective energization of said conductive runs to display side-by-side characters, an insulating layer covering said conductive runs and said interior surface in the area of the character positions and having a group of apertures therethrough for each cathode electrode group, each such aperture being aligned with one of said cathode electrodes, and insulating layer closely bordering the edges of each of said cathode electrodes to cover any projections from the borders of said electrodes and to define the shape of the character segments displayed, and a plurality of anode electrodes each positioned in operative relation with one of said cathode electrode groups and having a conductive lead extending through said envelope.

Claim 33

A flat display panel for displaying any one of a predetermined number of characters in each of a plurality of side-by-side character positions, comprising a gas-tight envelope formed of front and base plates closely spaced to one another and sealed together along a predetermined perimeter surrounding the character positions, the front and base plates forming outside walls of the envelope, an ionizable gas within said envelope at a pressure capable of sustaining glow discharge, at least the portions of the front plate which are aligned with the character positions being transparent to glow within the envelope to provide a viewing window for the characters to be displayed, a plurality of conductive runs extending along and supported on the interior surface of the base plate in the direction of the side-by-side character positions, a plurality of groups of cathode electrodes positioned side-by-side along said interior surface in said direction, each such group forming one of said character positions and each cathode electrode being in the general shape of a segment of a character to be displayed, each such conductive run being electrically connected to a cathode electrode in each of said cathode electrode groups, so that selective combinations of cathode electrodes in each such group can be energized by a selective energization of said conductive runs to display side-by-side characters, an insulating layer covering said conductive runs and said interior surface in the area of the character positions and having a group of apertures therethrough for each cathode electrode group, each such aperture being aligned with one of said cathode electrodes, and insulating layer closely bordering the edges of each of said cathode electrodes to cover any projections from the borders of said electrodes and to define the shape of the character segments displayed, and a plurality of anode electrodes each positioned in operative relation with one of said cathode electrode groups and having a conductive lead extending through said envelope.

Claim 34

A display panel as in claim 25 wherein the apertures in said insulating layer are smaller than their associated cathode segments to cover the edges of such segments.

Claim 35

A display panel as in claim 25 wherein the surface of said insulating layer is closer to the front plate than are the cathode electrodes, so that said electrodes are recessed in the apertures of said insulating layer

Claim 36

A gas discharge display panel having a plurality of side-by-side character positions along a predetermined line, in each of which any one of a number of characters can be displayed, comprising an envelope formed of front and rear plates sealed together along a closed perimeter sUrrounding the line of character positions to establish a gas tight enclosure about said character positions; an ionizable gas within said envelope at a pressure capable of sustaining glow discharge, a plurality of conductive runs extending along and supported on the interior surface of said rear plate in the direction of the line of side-by-side character positions, a plurality of groups of cathode electrodes positioned side-by-side along said interior surface in said direction, each such group forming one of said character positions, the cathode electrodes in each such group being disposed in substantially the same pattern, such pattern having a predetermined height to display characters of that height, and each cathode electrode being in the general shape of a segment of a character to be displayed, each such conductive run being electrically connected to a correspondingly positioned cathode electrode in each of said cathode electrode groups, so that selective combinations of said cathode electrodes in each such group can be energized by a predetermined energization of said conductive runs to provide a multi-character display, an insulating layer covering said conductive runs and said interior surface in the area of the character positions, and having a group of apertures therethrough for each group of cathode electrodes, each such aperture being aligned with one of said cathode electrodes, said insulating layer closely bordering the edges of each of said cathode electrodes to cover any projections from the borders thereof and to define the shape of the character segments displayed, and at least the majority of said conductive runs extending along said interior surface within the height of said cathode electrode patterns throughout the length of said cathode electrode groups and then continuing along said surface beyond said character positions, a plurality of anode electrodes each positioned in operative relation with one of said cathode electrode groups.

Claim 37

A gas discharge display panel having a plurality of side-by-side character positions along a predetermined line, in each of which any one of a number of characters can be displayed, comprising an envelope formed of front and rear plates sealed together along a closed perimeter sUrrounding the line of character positions to establish a gas tight enclosure about said character positions; an ionizable gas within said envelope at a pressure capable of sustaining glow discharge, a plurality of conductive runs extending along and supported on the interior surface of said rear plate in the direction of the line of side-by-side character positions, a plurality of groups of cathode electrodes positioned side-by-side along said interior surface in said direction, each such group forming one of said character positions, the cathode electrodes in each such group being disposed in substantially the same pattern, such pattern having a predetermined height to display characters of that height, and each cathode electrode being in the general shape of a segment of a character to be displayed, each such conductive run being electrically connected to a correspondingly positioned cathode electrode in each of said cathode electrode groups, so that selective combinations of said cathode electrodes in each such group can be energized by a predetermined energization of said conductive runs to provide a multi-character display, an insulating layer covering said conductive runs and said interior surface in the area of the character positions, and having a group of apertures therethrough for each group of cathode electrodes, each such aperture being aligned with one of said cathode electrodes, said insulating layer closely bordering the edges of each of said cathode electrodes to cover any projections from the borders thereof and to define the shape of the character segments displayed, and at least the majority of said conductive runs extending along said interior surface within the height of said cathode electrode patterns throughout the length of said cathode electrode groups and then continuing along said surface beyond said character positions, a plurality of anode electrodes each positioned in operative relation with one of said cathode electrode groups.

Claim 38

A display panel as in claim 28 wherein said insulating layer covers substantially all of the edges of all of said cathode electrodes to define the character segments as the uncovered portions of said cathode electrodes.

Claim 39

A flat display panel for displaying any one of a predetermined number of characters in each of a plurality of side-by-side character positions, comprising a gas-tight envelope containing an ionizable gas at a pressure capable of sustaining glow discharge, said envelope having a front plate with at least the portions thereof which are aligned with the character positions being transparent to glow within the envelope, to provide a viewing window for the characters to be displayed, an insulating plate having an interior surface thereof facing said front plate and closely spaced thereto, a plurality of elongated conductive runs extending along said interior surface in a predetermined direction, a first layer of insulating material on said conductive runs, a plurality of groups of cathode electrodes aligned side-by-side on said insulating layer along said predetermined direction, with at least the majority of said conductive runs passing directly behind all of said cathode electrode groups, the cathode electrodes in each of said cathode electrode groups being disposed in substantially the same pattern, and each such group forming one of said character positions, said first insulating layer having a plurality of apertures therethrough, each aligned with one of said cathode electrodes, each such conductive run being electrically connected through one of said apertures in said insulating layer to the correspondingly positioned cathode electrode in each of said cathode electrode groups, so that selective combinations of said cathode electrodes in each such group can be energized to provide a multi-character display, a second insulating layer covering said first layer and having a group of apertures therein for eaCh group of cathode electrodes, the border of each said aperture contiguous the border of one of said cathode electrodes, and a plurality of anode electrodes each positioned in operative relation with one of said cathode electrode groups.

Claim 40

A flat display panel for displaying any one of a predetermined number of characters in each of a plurality of side-by-side character positions, comprising a gas-tight envelope containing an ionizable gas at a pressure capable of sustaining glow discharge, said envelope having a front plate with at least the portions thereof which are aligned with the character positions being transparent to glow within the envelope, to provide a viewing window for the characters to be displayed, an insulating plate having an interior surface thereof facing said front plate and closely spaced thereto, a plurality of elongated conductive runs extending along said interior surface in a predetermined direction, a first layer of insulating material on said conductive runs, a plurality of groups of cathode electrodes aligned side-by-side on said insulating layer along said predetermined direction, with at least the majority of said conductive runs passing directly behind all of said cathode electrode groups, the cathode electrodes in each of said cathode electrode groups being disposed in substantially the same pattern, and each such group forming one of said character positions, said first insulating layer having a plurality of apertures therethrough, each aligned with one of said cathode electrodes, each such conductive run being electrically connected through one of said apertures in said insulating layer to the correspondingly positioned cathode electrode in each of said cathode electrode groups, so that selective combinations of said cathode electrodes in each such group can be energized to provide a multi-character display, a second insulating layer covering said first layer and having a group of apertures therein for eaCh group of cathode electrodes, the border of each said aperture contiguous the border of one of said cathode electrodes, and a plurality of anode electrodes each positioned in operative relation with one of said cathode electrode groups.

Claim 41

A display panel as in claim 30 wherein the surface of said second insulating layer is closer to the front plate than is the surface of said cathode electrodes, so that the cathode electrodes are recessed, one in each of the apertures in said second insulating layer.