Method of making cathode ray tube with integral light trapping filter

Claim 1

A METHOD OF PRODUCING A SPACE LATTICE TYPE AMBIENT LIGHT TRAPPING FILTER FOR USE IN A CATHODE RAY TUBE TO IMPROVE THE IMAGE PRESENTED THEREBY, COMPRISING: PROVIDING A FIRST LATERALLY EXTENSIVE, TRANSPARENT LAYER OF GLASS; DEPOSITING ON THE MAJOR PORTION OF THE AREA OF ONE FACE THEREOF SUBSTANTIALLY OPAQUE BLACK FRIT IN A DESIRED GRID PATTERN OF ALTERNATING OPAQUE AND CLEAR AREAS AND UNITING IT WITH SAID FIRST LAYER; DEPOSITING ON THE COMBINED LAYER AND GRID OVER THE MAJOR PORTION OF THE EXPOSED AREA A SUBSTANTIALLY UNIFORM THIN LAYER OF CLEAR FRIT; FUSING SAID LAYER TO MAKE IT INTEGRAL WITH THE COMBINED LAYER AND GRID; DEPOSITING ON THE MAJOR PORTION OF THE AREA OF THE NEW EXPOSED FACE SUBSTANTIALLY OPAQUE BLACK FRIT IN A GRID PATTERN SUBSTANTIALLY IDENTICAL WITH THE FIRST GRID PATTERN, IN DEPTHWISE REGISTRY THEREWITH AND SPACED DEPTHWISE FROM SAID FIRST GRID PATTERN BY THE THICKNESS OF SAID FUSED LAYER OF CLEAR FRIT; AND REPEATING THE CYCLE UNTIL THE DESIRED NUMBER OF ADDED LAYERS AND GRID PATTERNS HAVE BEEN DEPOSITED AND UNITIZED TO PRODUCE A MULTIPLICITY OF DEPTHWISE DIRECTED VIEWING CELLS HAVING AXES IN PREDETERMINED DIRECTIONAL RELATION TO EACH OTHER.