Cathodoluminescent display device including conductive or semiconductive coating on the phosphor
AssigneeSmiths Industries Public Limited Company
InventorsPaul H. J. Beatty, Bernard R. Venn
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Abstract
A cathodoluminescent display device, for example a low-voltage vacuum fluorescent display device, has a source of low-voltage electrons and cathodoluminescent layer for excitation by the low-velocity electrons which comprises particles of phosphor material, for example a sulphide, selenide, telluride or oxy-sulphide phosphor, thar are treated to increase their surface conductivities by, for example, deposition of a surface coating comprising conductive or semi-conductive material.
Claims29
A cathodoluminescent display device having means for generating low-velocity electrons with an excitation potential of about 10 to about 100 electron volts and a cathodoluminescent layer which is to emit light in response to excitation thereof by said low-velocity electrons, in which said cathodoluminescent layer comprises particles of a phosphor material having a coating of a material selected from the group of an electrically conductive or semi-conductive material to increase the surface conductivity of said particles, said coating permitting the passage of electrons at said low velocity to excite said phosphor particles.
A cathodoluminescent display device having electron-emitting means for generating low-velocity electrons with an excitation potential of about 10 to about 100 electron volts and a cathodoluminescent layer so disposed as to have impinging thereon the electrons from said electron-emitting means, said cathodoluminescent layer comprising particles of zinc sulphide activated with about 0.05 percent by weight of copper and about 0.4 percent by weight of manganese and with said particles having a diameter of about 1 .mu.m, said particles being coated with copper by subjecting said phosphor material to an aqueous solution of cupric ions to provide a particle coating with a thickness of about 3 Angstroms to increase the surface conductivity of said particles, said coating permitting the passage of electrons at said low velocity to excite said phosphor particles.
Dependencies are inferred from the claim text.