GB1462769A - Methods of producing luminescent images - Google Patents

Abstract

1462769 Uses of luminescence KODAK Ltd 20 Dec 1974 [12 Oct 1973] 47807/73 Heading C4S A method of producing a luminescent image in a binder layer incorporating a thermoluminescent material comprises imagewise exposing to radiation while heating to from 80 to 300‹ C, the material being as prepared by the method of U.K. Patent Specification 1347672. The preferred radiation is X-rays and the material is preferably insensitive to radiation >300 nm. From 80 to 150‹ C. the image persistence may be several seconds but is negligible at 200‹C fluoroscopic screens used with a pulse radiolysis unit may have variable afterglow depending on temperature for sequential image displays. Binders may be polymethylmethacrylate, polystyrene or a cold setting acrylic resin. The layer may be self-supporting or coated on a substrate which may be electrically conductive or carry a conductive layer for electrical heating. Alternatively, a self supporting layer may be contacted with an electrically heated layer. A substrate (e.g. Pyrex, R.T.M.) may for example carry vacuum deposited Al producing 10-15 # resistance. The Al layer is overcoated on two opposing edges to produce uniform power distribution. Wire electrodes are connected by Ag paste. Dimensions and concentrations are disclosed. Panel temperature may be determined by a sensor or a previously determined temperature voltage relationship. In the method of Specification 1347672 cadmium sulphate is heated in the presence of an alkali metal fluoride or sulphate, as a flux, with an inorganic compound of Al, Mn, Nd, Pr, Tb, Dy, Ho, or Bi as dopant. A water soluble salt of Pb, Tl or Sm may also be used.