| 摘要 |
A radiographic image conversion screen comprises a support, a fluorescent layer consisting of a blue-emitting phosphor (I) formed on the support and a second fluorescent layer, consisting of a green- emitting rare earth phosphor (II), formed on the first layer. The screen is particularly for use in medical diagnosis. It has a speed at least as high as conventional screens contg. a phosphor of type (II) and the inclusion of phosphor (I) gives superior sharpness and contrast without degrading the granularity. When used as an intensifying screen, it has the added advantage that the speed is less dependent on the X-ray tube voltage.
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