Abstract: The invention relates to a method for determining the thickness of an OPC layer 24 that is strongly absorptive to light at a first wavelength and substantially transmissive to light at a second wavelength. According to the method, the OPC layer is illuminated with light from an array 34 of fluorescent lamps 36 and the light transmitted through the layer is incident on a first filter 42 that is transmissive to light of the first wavelength. A first light intensity pattern transmitted through the first filter is sensed and stored in a first memory frame. Then OPC layer is illuminated again with light and the light transmitted through the layer is incident on a second filter 44 transmissive to light of the second wavelength. A second light intensity pattern transmitted through the second filter is sensed and stored in a second memory frame. The ratio of the first light intensity pattern and the second light intensity pattern is determined and utilized to calculate the thickness of the layer.

Abstract: In accordance with the present invention, a method of electro-photographically manufacturing a luminescent screen assembly on an interior surface of a faceplate panel 12 for a color CRT 10 includes the steps of coating the interior surface of the faceplate panel with a volatilizable, organic conductive solution to form an organic conductive (OC) layer 32, and overcoating the OC layer with a volatilizable, organic photoconductive solution to form an organic photoconductive (OPC) layer 34. The step of overcoating the OC layer to form the OPC layer is improved by the substeps of: grounding the OC layer; providing an organic photoconductive (OPC) solution comprising a resin, an electron donor material and electron acceptor material, and a suitable solvent; and spraying electrostatically-charged droplets of the OPC solution onto the OC layer, with at least one electrostatic spray gun 47, to provide an OPC layer, having uniform thickness, overlying the OC layer.