Patent ID: 6169360
Filing Date: 2001-01-02
Classification: G21K,H01J

Abstract:
An X-ray image intensifier, comprising a substrate of aluminum or aluminum alloy pressed to have a substantially spherical shape with a concave surface and an input screen having an X-ray excited phosphor layer which is formed of an aggregate of columnar crystals disposed on the concave surface and a photocathode disposed on the phosphor layer, wherein: the concave surface of the substrate has gentle irregularities having substantially no directivity, and when the gentle irregularities are measured for their profile by a measurement given below, an average length between the bottoms of the neighboring irregularities is in a range of 50 .mu.m to 300 .mu.m, and an average height from peaks to bottoms of the neighboring irregularities in a range of 0.3 .mu.m to 4.0 .mu.m; where the measurement determines an average length between the neighboring bottoms in the horizontal direction and an average height from peaks to bottoms from a profile of irregularities obtained by linearly measuring in a range of 2.0 mm to 4.0 mm in a given direction on the center region of the concave surface of the substrate; but minute irregularities which have a length of less than 20 .mu.m between the neighboring bottoms in the horizontal direction and a height of less than 0.2 .mu.m from peaks to bottoms and minute irregularities which have a length of 5 .mu.m or below in the horizontal direction regardless of the height are excluded from the peaks or bottoms for measuring.