Bmc Industries, Inc.

Roland H Thoms

An etching system for etching openings in a metal web including multiple etching station for etching a metal web from opposite sides, with each of the etching stations including a set of first bank of oscillatable nozzles located in a first chamber in the etching station, with the first bank of oscillatable nozzles having predetermined spacings from one another and operable for directing etchant at a first side of a metal web and a second bank of oscillatable nozzles located in a second chamber in the etching station, with the second bank of oscillatable nozzles having a predetermined spacing substantially identical to the first bank of oscillatable nozzles, with the second set of oscillatable nozzles laterally offset from the first set of nozzles, so they do not spray on directly opposite regions located on the metal web, with the banks of the nozzles in adjacent etching stations offset from each other with the oscillation axis of the nozzles at an angle off normal, so that etchant is sprayed in elliptical patterns on the metal web to more uniformly distribute etchant across the metal web, including a system to oscillate the nozzles in different waveforms in response to measurements of openings in the metal web to compensate for changing etching conditions or changes in the thickness of the metal web without having to change the etchant flow rate to the metal web or the etchant pressure in the nozzles. Thus, the system includes hydraulic cylinders to oscillate the nozzles in accordance with a waveform different from the original waveform in response to a measurement of the metal web and allows the system to compensate, if necessary, for changing etching conditions or changes in the thickness of the metal web.

Etchant control system

A shadow mask for use in forming a television tube having a plurality of openings therein with the mask grade side having an average centerline roughness R.sub.ag, which is less than cone side average centerline roughness R.sub.ac so that when a plurality of aperture masks are stacked with the grade side of one mask in contact with the cone side of an adjacent mask, the greater roughness of the cone side provides sufficient spacing between the shadow masks to allow gasses to enter between the stacked masks to permit batch annealing of the stack of masks without having the stacked masks adhere to one another during the annealing process.

Stackable aperture masks

An etching system for etching openings in a metal web including multiple etching station for etching a metal web from opposite sides with each of the etching stations including a set of first bank of oscillateable nozzles located in a first chamber in the etching station, with the first bank of oscillateable nozzles having predetermined spacings from one another, and operable for directing etchant at a first side of a metal web and a second bank of oscillateable nozzles located in a second chamber in the etching station, with the second bank of oscillateable nozzles having a predetermined spacing substantially identical to the first bank of oscillateable nozzles with the second set of oscillateable nozzles laterally offset from the first set of nozzles, so as not to spray on directly opposite regions located on the metal web with the banks of the nozzles in adjacent etching stations offset from each other with the oscillation axis of the nozzles is at an angle off normal so that etchant is sprayed in elliptical patterns on the metal web to more uniformly distribute etchant across the metal web.

Etchant distribution apparatus

A photo printing plate having an upper air evacuation channel and a lower air evacuation channel with the lower air evacuation channel formed in a emulsion layer and the upper air evacuation channels formed by spacers located partially on top of the opaque pattern that projects outward from the emulsion layer and partially on top of the nonopaque emulsion layer adjacent to the opaque pattern to provide an air evacuation channel formed by the evacuation channels in the emulsion surface and the spacers so that the air can be rapidly evacuated between the photo printing plate and a layer of etchant resist while maintaining the layer of etchant resist less than 10 microns from the top surface of the photo printing plate.

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Cortland, NY, United States of America

Roland H Thoms