Apparatus for forming apertures in a thin metal tape such as a shadow mask for a color television display tube

Claim 1

In an apparatus for etching apertures in a continuously moving thin metal tape, both surfaces of which tape have previously been provided with apertured etch resistant coatings, by bringing said tape into contact with an etching fluid and then removing said etching fluid from said tape, the improvement wherein said apparatus in addition comprises means for moving a section of an endless belt of an etch resistant synthetic resin material having a width at least as large as that of said metal tape in the same direction and at the same rate as said metal tape, means for bringing said section of said belt into substantial contact with a surface of said thin metal tape while both tape and belt are in motion, and means, prior to bringing said metal tape into contact with said etching fluid, for temporarily causing at least the edges of said belt to adhere to said thin metal tape in a manner such that upon bringing said tape into contact with said etching fluid, the etching fluid is prevented from reaching said surface of said tape in contact with said belt while the opposing surface of said tape is being etched.