Vacuum fluorescent display device with circular polarizer

Claim 2

In a vacuum fluorescent display device having at least one electrically heated thermoelectron-emitting filament, at least one phosphor-coated anode, wherein said filament and anode are sealed in an enclosure having a hard vacuum therein, the improvement comprising: (a) an electrostatic lens inside said enclosure interposed in the line of sight between the viewer and said filament. (b) said electrostatic lens being a self-supporting substantially planar metallic sheet having a regular pattern of holes therethrough, said sheet and holes in combination forming a foraminous screen; (c) said holes comprising from about 20 to about 50 percent of the screen area; (d) a circular polarizer interposed in the line of sight between the viewer and said screen; (e) a specularly reflecting surface on at least the side of said screen nearer said viewer; and (f) said foraminous screen being connected to a positive voltage with respect to said filament.

Claim 3

The display device recited in claim 1, further comprising said foraminous screen being disposed intermediate said enclosure and said filament and spaced therefrom.

Claim 4

The display device recited in claim 2, further comprising: (a) a glass substrate; (b) at least one electrical conductor being sealably embedded in said glass substrate and extending substantially inside and substantially outside said enclosure; (c) the end of said at least one electrical conductor extending inside said enclosure being spaced from said substrate; and (d) said foraminous screen being attached to said end and thereby being at least partially supported within said enclosure spaced from said filament and said enclosure.

Claim 5

The display device recited in claim 3 wherein said filament and said at least one phosphor-covered anode are all supported upon said glass substrate.

Claim 6

A vacuum fluorescent display device comprising: (a) an insulating substrate; (b) a plurality of phosphor coated anodes disposed in a plane on said substrate; (c) at least one cathode suspended above said phosphor coated anodes; (d) at least one rigid support leg passing sealingly through said substrate and having a first portion extending substantially normal to and above said substrate and a second portion extending substantially below said substrate; (e) a self-supporting substantially planar metallic sheet disposed substantially parallel to said plane spaced above said cathode; (f) said metallic sheet having a regular pattern of holes therethrough, said sheet and holes in combination forming a foraminous screen; (g) said metallic sheet being affixed to, and at being at least partly supported by said first portion; (h) said holes comprising from about 20 to about 70 percent of the screen area; (i) a concave cover sealed at a continuous closed perimeter thereof to said substrate, said substrate and cover together forming a hermetically sealed enclosure which contains said anodes, cathode and foraminous screen; (j) a transparent panel in said concave cover effective to permit observation of said anodes; (k) a circular polarizer having first and second parallel faces; (l) said circular polarizer being disposed with its faces substantially parallel to said planar metallic sheet and located in the line of sight between the viewer and said foraminous screen; (m) a specularly reflecting surface on at least the side of said foraminous screen nearer said circular polarizer; and (n) means for connecting a voltage to said foraminous screen which is positive with respect to said cathode.

Claim 7

A vacuum fluorescent display device comprising: (a) an insulating substrate; (b) a plurality of phosphor coated anodes disposed in a plane on said substrate; (c) at least one cathode suspended above said phosphor coated anodes; (d) at least one rigid support leg passing sealingly through said substrate and having a first portion extending substantially normal to and above said substrate and a second portion extending substantially below said substrate; (e) a self-supporting substantially planar metallic sheet disposed substantially parallel to said plane spaced above said cathode; (f) said metallic sheet having a regular pattern of holes therethrough, said sheet and holes in combination forming a foraminous screen; (g) said metallic sheet being affixed to, and at being at least partly supported by said first portion; (h) said holes comprising from about 20 to about 70 percent of the screen area; (i) a concave cover sealed at a continuous closed perimeter thereof to said substrate, said substrate and cover together forming a hermetically sealed enclosure which contains said anodes, cathode and foraminous screen; (j) a transparent panel in said concave cover effective to permit observation of said anodes; (k) a circular polarizer having first and second parallel faces; (l) said circular polarizer being disposed with its faces substantially parallel to said planar metallic sheet and located in the line of sight between the viewer and said foraminous screen; (m) a specularly reflecting surface on at least the side of said foraminous screen nearer said circular polarizer; and (n) means for connecting a voltage to said foraminous screen which is positive with respect to said cathode.

Claim 8

Apparatus recited in claim 5 further comprising: (a) at least two cathode support pins passing sealingly through and being supported by said substrate; and (b) said cathode being supported spaced from said substrate and fed electrical power by said cathode support pins.