Method for manufacturing plasma display panel, inspection method for inspecting phospor layer and inspection apparatus for inspecting phosphor layer

Abstract

A phosphor paste is applied to inner surfaces of a cell. Then, a conveyer moves a substrate relative to a CCD camera at a constant speed. Simultaneously, two LEDs radiate visible light onto a portion, to be inspected, of the substrate. The visible light is light configured to have a wavelength so as to be able to prevent the phosphor of the phosphor paste from being excited and emitting light and reflected by a liquid surface of the phosphor paste to produce reflected light. Thereafter, the CCD camera captures an image of the phosphor paste and a data processor processes the received image data, and determines whether a phosphor layer formed by drying the phosphor paste will normally be formed, prior to formation of phosphor layer.

1 . An inspection method for inspecting a phosphor layer, said phosphor layer being formed by applying a phosphor material in the form of paste to a surface of an insulating substrate whose surface is divided into a plurality of cells and drying said phosphor material, said inspection method comprising:
 determining whether an amount of said phosphor material in each of said cells is equal to or less than a predetermined amount based on a size of an area of a surface of said phosphor layer that produces a maximum intensity of a reflected light when visible light is radiated onto a whole surface of said phosphor layer.   
     
     
         2 . The inspection method for inspecting the phosphor layer according to  claim 1 , wherein the step of determining said pattern of light reflected from each of said plurality of cells comprises the steps of;
 capturing an image of the applied phosphor material while radiating visible light onto a surface of said applied phosphor material in order to obtain image data indicative of said image of said applied phosphor material;   distinguishing patterns of images each consisting of light reflected from each of said plurality of cells from one another based on said image data indicative of said image of said applied phosphor material; and   inspecting whether said phosphor material is normally being applied to each of said plurality of cells based on results obtained by distinguishing said images from one another in order to determine whether or not said phosphor layer will normally be formed.   
     
     
         3 . An inspection apparatus for inspecting a phosphor layer, said phosphor layer being formed by applying a phosphor material in the form of paste to a surface of an insulating substrate whose surface is divided into a plurality of cells, said inspection apparatus comprising:
 a visible light source disposed above said substrate and illuminating said phosphor material being applied in the form of paste;   a camera disposed above said substrate and capturing an image of said phosphor material being applied: and   a data processor for identifying a pattern of light reflected from each of said plurality of cells based on image data indicative of said image of said phosphor material captured by said camera and determining whether an amount of said phosphor material in each of said cells is equal to or less than a predetermined amount based on a size of an area of a surface of said phosphor layer that produces a maximum intensity of the reflected light when visible light is radiated onto a whole surface of said phosphor layer.   
     
     
         4 . The inspection apparatus for inspecting a phosphor layer according to  claim 3 , wherein said camera is disposed directly above said phosphor layer whose image is to be captured by said camera and wherein said visible light source is employed as one of two light sources and said two light sources are disposed so as to interpose said camera therebetween. 
     
     
         5 . The inspection apparatus for inspecting a phosphor layer according to  claim 3 , wherein said visible light source output light has a wavelength range so as to be able to prevent said phosphor material from being excited and emitting light. 
     
     
         6 . The inspection apparatus for inspecting a phosphor layer according to  claim 3 , further comprising convey unit for moving said substrate relative to said camera wherein said camera scans a surface of said substrate to capture said image of said phosphor material by making said convey unit cause said substrate to move relative to said camera while allowing said camera to capture an image of a part of said substrate.