Craig Clay Eshleman - Pequea PA Charles Michael Wetzel - Lititz PA Randall Eugene McCoy - Fort Littleton PA Leo B. Kriksunov - Ithaca NY Lance Benjamin - LaFayette NY Derek Harris - Woodbury MN Thomas R. Sage - Endwell NY
Assignee:
BMC Industries, Inc. - Minneapolis MN Thomson Consumer Electronics - Indianapolis IN
International Classification:
C25F 300
US Classification:
216 12, 248683, 414606, 134 41, 335285
Abstract:
In an improved method of etching apertures in a thin metal sheet to form a shadow mask for a color picture tube, the metal sheet has a first acid-resistant stencil on one major surface thereof and a second acid-resistant stencil on the other major surface thereof. At least one of the stencils has openings therein at locations of intended apertures. The improvement comprises the steps of magnetically holding the metal sheet with a flat magnetic assembly, and moving the magnetic assembly magnetically holding the metal sheet thereon through an etching chamber. The magnetic assembly includes a magnetic layer that is supported on an acid-resistant board.