Abstract text

An assembly for vaporizing raw materials in order to prepare vapor deposited phosphor materials comprises a crucible provided with two plates or covers, wherein one thereof is an outermost plate or cover provided with a perforation pattern, selected from the group consisting of one or more slits, in series or in parallel, and of openings having same or different diameter, randomly or regularly distributed over said cover, moreover covering said crucible having a bottom and surrounding side walls with a height “h” and wherein said crucible contains raw materials, is characterized in that a second plate is mounted internally in the crucible at a distance from said outermost cover plate being less than ⅔ of said side wall height “h”.