Isis Innovation Limited

Garreth Wakefield

Peter James Dobson

Phosphor compositions are prepared by treating metal oxides or mixed-metal oxides with refractory metals to form cathodoluminescent phosphors stimulatable by electrons of very low energy. The phosphors comprise 90% to 100% of a mixed metal oxide M ,T O (where M is a metal selected from Zn, Sn, In, Cu, and combinations thereof; T is a refractory metal selected from Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and combinations thereof; and O is Oxygen, x, y, and z being chosen such that z is at most stoichiometric for M T O ) and 0% to 10% of a dopant comprising a substance selected from a rare earth element of the lanthanide series, Mn, Cr, and combinations thereof, or stoichiometrically excess Zn, Cu, Sn, or In. A blue-light-emitting phosphor based on ZnO treated with Ta O or Ta to form Ta Zn O is characterized by CIE 1931 chromaticity values x and y, where x is between about 0.14 and 0.20 and y is between about 0.05 and 0.15. In preferred embodiments, a process is specially adapted for forming the phosphor in an electrically-conductive thin-film or surface-layer form in situ during fabrication of displays. A preferred in situ process has an integrated etch stop, which precisely defines the depth of an opening in a field-emission display structure utilizing the low-energy-electron excited phosphor. A field-emission display comprises cells, each having a field-emission cathode and an anode comprising at least one cathodoluminescent phosphor. Arrangements of various color phosphors may be made by selective deposition of suitable dopants. The display cell structures may also have gate elements for controlling electron current flowing to the anode and its phosphor when suitable voltages are applied.

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Oxford, United Kingdom

Garreth Wakefield