| abstract |
The invention concerns a black matrix in colour picture tubes, a positive photoresist composition, an agent for protecting a black matrix and a method of producing the latter. The object of the invention is to provide a black matrix which is produced by means of a positive photoresist composition, permits good structuring ability between exposed and unexposed regions, and reduces the method of producing the black matrix to a small number of technological steps. This object is achieved by obtaining a black matrix which consists of a light-absorbent matrix and can be produced from a positive photoresist composition consisting of a suspension which contains one or a plurality of compounds which indirectly or directly release gaseous compounds under the effect of light, a black pigment and suspension-stabilizing additives which enhance wetting and/or render the solution adhesive. The object is further achieved by obtaining an agent for protecting the light-absorbent matrix, which agent can be produced from a negative photoresist composition comprising a water-soluble organic polymer, a cross-linking actinic component, an alkylsilicate and water, said protecting agent having a pH of between 6 and 7.5. |