Reducing aperture-size of shadow mask in painting black matrix CRT screen
US3989523A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Feb 10, 1975 |
| Grant date | Nov 2, 1976 |
| Priority date | — |
| Expiry date | Feb 10, 1995 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH01J9/144
- WIPO fieldElectrical machinery, apparatus, energy
- WIPO sectorElectrical engineering
Abstract
A method for making a black matrix type shadow mask color television tube. A shadow mask with standard size apertures is sprayed with a black brushing cellulose lacquer while at the same time drawing air, at high velocities, through the apertures to reduce the size of said apertures. A sufficient quantity of sprayed lacquer is utilized to obtain a 10% reduction in aperture size. The mask is then utilized to coat the tube's screen, i.e. its inside face, with a colloidal graphite paint to form the required adherent black matrix surface on said screen having a plurality of holes therein. The apertures of the shadow mask are then restored to their original size by rinsing the mask in acetone to remove the lacquer coating. The resultant original size apertures of the shadow mask are utilized to form the pattern of phosphor dots on the screen overlapping the holes in the black matrix.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.