Abstract An apparatus is depicted for re-etching the apertures of a color cathode-ray tube shadow mask of the type which comprises a multiplicity of apertures arranged in a predetermined pattern and having an initial predetermined size relationship from aperture to aperture. The shadow mask has a predetermined first set of apertures which are susceptible of enlargement at a faster rate than a predetermined second set of apertures upon exposure to an etchant capable of attacking the shadow mask. The apparatus comprises means for supporting the shadow mask and spray means for applying more of the etchant to the second set of apertures than to the first set of apertures such as to at least partially compensate for the greater susceptibility to enlargement by etching of the first set of apertures than the second set of apertures and promoting equalization of enlargement of both sets of apertures. The spray means is depicted as including a plurality of spray nozzles and a shield for at least partially shielding the shadow mask from the spray nozzles such that a greater amount of etchant is applied to the second set of apertures than to the first set of apertures.
Apparatus for re-etching the apertures of a color cathode-ray tube shadow mask of the type which comprises a convex-concave configuration, a multiplicity of apertures arranged in a predetermined pattern and having an initial predetermined size relationship from aperture-to-aperture, a predetermined first set of said apertuRes being susceptible of enlargement at a faster rate than a predetermined second set of apertures upon exposure to an etchant capable of attacking said shadow mask, said apparatus comprising: support means for supporting said shadow mask in air with the convex side down; and spray means including a plurality of spray nozzles positioned beneath said mask for projecting vertically upward a varying quantity of said etchant to said second set of apertures relative to said first set of apertures such as to at least partially compensate for the greater susceptibility to enlargement by etching of said first set of apertures than said second set of apertures and promote equalization of enlargement of both sets of apertures.
Claim 2
Dependent Claim
161 words
Apparatus for re-etching the apertures of a color cathode-ray tube shadow mask of the type which comprises a convex-concave configuration, a multiplicity of apertures arranged in a predetermined pattern and having an initial predetermined size relationship from aperture-to-aperture, a predetermined first set of said apertuRes being susceptible of enlargement at a faster rate than a predetermined second set of apertures upon exposure to an etchant capable of attacking said shadow mask, said apparatus comprising: support means for supporting said shadow mask in air with the convex side down; and spray means including a plurality of spray nozzles positioned beneath said mask for projecting vertically upward a varying quantity of said etchant to said second set of apertures relative to said first set of apertures such as to at least partially compensate for the greater susceptibility to enlargement by etching of said first set of apertures than said second set of apertures and promote equalization of enlargement of both sets of apertures.
Claim 3
Dependent Claim
50 words
Apparatus as defined by claim 1 wherein said support means supports said mask so that said convex surface is toward said spray means and said spray means includes shield means for shielding and limiting the quantity of said etchant being projected on said first set of apertures by said spray.
Claim 4
Dependent Claim
63 words
Apparatus as defined by claim 2 wherein said shield means comprises a fixed perforate shield interposed between said spray nozzles and that portion of said shadow mask comprising said second set of apertures, covering said second set of apertures to cause a lesser quantity of said etchant to be applied to said first set of apertures than to said second set of apertures.
Claim 5
Dependent Claim
53 words
Apparatus as defined by claim 2 wherein said shield means comprises an imperforate shield adapted to be moved into and out of a shielding relationship between said spray nozzles and said shadow mask effectuating a differentiating quantity of projecting etchant on said first set of apertures relative to said second set of apertures.