Some efficient architecture simulation tech-niques

In forming a light-absorbing grille or mat for a black-surround color tube, the screen area is covered with clear but sensitized polyvinyl alcohol (pva) and is thereafter exposed to develop a family of pva dots individually covering an elemental area of the screen that is subsequently to receive a deposit of one of three phosphors, green, blue and red. The exposure step is accomplished with seven light sources one of which is positioned to simulate one of the electron guns of the tube and this source accomplishes first order printing or exposure of the pva layer. The remaining six light sources are symmetrically and equidistantly spaced with respect to the first light source to accomplish second order printing or exposure of the same elemental areas exposed by the first mentioned light source. In this fashion each elemental screen area that is to receive a phosphor deposit is concurrently subjected to exposure from seven light sources.