Charles J Wetzel

US Patent:

6562249, May 13, 2003

Filed:

Jul 10, 2001

Appl. No.:

09/902456

Inventors:

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.