Abstract: A circuit and method of driving a display panel requiring gray scale control wherein the voltage applied to a row of pixels is equal to the sum of voltages of opposite sign with respect to ground applied respectively to the row electrode and column electrodes whose intersection with the row defines the pixels. Gray scale is realized through modulation of the voltage applied to the column electrodes. Typically for video application, 256 individual gray levels are required corresponding to luminance levels ranging from zero (no emissive luminance) to full luminance. The required luminance for each gray level is not a linear function of the gray level number but rather corresponds to an approximate quadratic function of this number. The present invention facilitates generation of luminance values for each gray level that approximates this functional dependence (i.e. Gamma corrected) with a non-linear voltage ramp terminated by a digital clock having 256 (8 bit) resolution.

Abstract: A driver apparatus for an electroluminescent display comprising a plurality of rows to be scanned and a plurality of columns which intersect the rows to form a plurality of pixels, comprises addressable row drivers, each row driver applying an output voltage to its associated row when addressed. The value of the output voltage is approximately equal to the numerical average of the threshold voltage for the electroluminescent display and the voltage required to provide the maximum desired pixel luminance for the electroluminescent display. Bipolar column drivers each supply an output voltage to its associated column. The output voltage is either positive or negative depending on the desired luminance of the pixels. The range of both positive and negative column output voltages is from zero volts to about one half of the difference between the threshold voltage and the voltage to provide the desired maximum pixel luminance for the electroluminescent display.

Abstract: A circuit and method of driving a display panel requiring gray scale control wherein the voltage applied to a row of pixels is equal to the sum of voltages of opposite sign with respect to ground applied respectively to the row electrode and column electrodes whose intersection with the row defines the pixels. Gray scale is realized through modulation of the voltage applied to the column electrodes. Typically for video application, 256 individual gray levels are required corresponding to luminance levels ranging from zero (no emissive luminance) to full luminance. The required luminance for each gray level is not a linear function of the gray level number but rather corresponds to an approximate quadratic function of this number. The present invention facilitates generation of luminance values for each gray level that approximates this functional dependence (i.e. Gamma corrected) with a non-linear voltage ramp terminated by a digital clock having 256 (8 bit) resolution.

Abstract: An EL element 1 comprises EL functional layers 6, 10 comprising Ga2O3:Eu between a thick film insulator layer 16 and an upper electrode 12 provided on a substrate 2 on which a lower electrode 4 was formed and a light-emitting layer 8 comprising MgGa2O4 formed therebetween. The EL functional layers 6, 10 have the dual functions of insulating layers and electron doping layers. Due to this, the EL element 1 has a low drive voltage and high light-emitting brightness, and the structure of the EL element is simplified.

Abstract: An extended area uniform light source providing uniform luminance is taught for displays and other applications where the light emission can be planar or have curvature. The uniform light source is achieved using a combination of a blue light-emitting electroluminescent layer and a highly stable inorganic photoluminescent color conversion layer to tailor the color spectrum of the emitted light. The invention thus encompasses the uniform light source, displays incorporating the uniform light sources as well of methods of making such light sources and displays.

Abstract: The present invention is an electroluminescent display that incorporates a laminated seal that inhibits exposure of display components to atmospheric contaminants and to a sealing process for fabrication of the same. The sealed electroluminescent display comprises a substrate upon which is constructed a thick dielectric electroluminescent display covered by a laminated seal comprising a lower multi-functional polymer film and an upper inorganic film that provides a barrier layer to inhibit exposure of the electroluminescent display structure to an atmospheric contaminant.

Abstract: The invention is a sealed thick film dielectric display where the display comprises a thick film dielectric display structure and an adhesive layer provided over the display structure. The invention also provides a seal where the seal comprises an adhesive layer bonded to the underside of a cover plate and to the surface of a thick film dielectric electroluminescent display. The seal substantially inhibits the exposure of display components to atmospheric contaminants.

Abstract: The present invention is a method for gettering undesirable atomic species from a vaporizing atmosphere during deposition of multi-element thin film phosphor compositions. The method comprises vaporizing one or more getter species immediately prior and/or simultaneously during the deposition of a phosphor film composition within a deposition chamber. The method improves the luminance and emission spectrum of phosphor materials used for full colour ac electroluminescent displays employing thick film dielectric layers with a high dielectric constant.

Abstract: A novel sub-structure of a thick film dielectric electroluminescent display and a thick film dielectric electroluminescent display incorporating the same is provided. The sub-structure comprises a barrier layer between a substrate and a thick film dielectric layer. The barrier layer is chemically inert with respect to the substrate and the thick film dielectric layer and the barrier layer inhibits diffusion of at least one chemical species therethrough. This sub-structure results in a higher capacitance for the thick dielectric layer, which provides higher display luminance and a reduced tendency for dielectric breakdown of the thick dielectric layer. The barrier layer permits for lower cost substrates, such as glass, to be used.

Abstract: A novel and improved composite thick film dielectric structure is provided to improve the operating stability of phosphors used in thick dielectric ac electroluminescent displays. The novel structure comprises one or more aluminum oxide layers disposed between the composite thick dielectric layer and the bottom of the phosphor layer of these displays.

Abstract: A novel laminate is provided to improve the operating stability of thioaluminate based phosphors used in ac thick film dielectric electroluminescent displays. The novel structure comprises a rare earth activated alkaline earth thioaluminate phosphor thin film layer and a magnesium oxide or magnesium oxide containing layer provided directly adjacent and in contact with the bottom of the phosphor thin film layer. The invention is particularly applicable to phosphors used in electroluminescent displays that employ thick dielectric layers subject to high processing temperatures to form and activate the phosphor films.

Abstract: A novel laminate is provided to improve the operating stability of thioaluminate based phosphors used in ac thick film dielectric electroluminescent displays. The novel structure comprises a rare earth activated alkaline earth thioaluminate phosphor thin film layer and an aluminum oxide or aluminum oxynitride layer provided directly adjacent and in contact with the bottom of the phosphor thin film layer. The invention is particularly applicable to phosphors used in electroluminescent displays that employ thick dielectric layers subject to high processing temperatures to form and activate the phosphor films.

Abstract: The present invention is a method for the deposition of a thin film of a pre-determined composition onto a substrate, the thin film comprising ternary, quaternary or higher sulfide compounds selected from the group consisting of thioaluminates, thiogallates and thioindates of at least one element from Groups IIA and IIB of the Periodic Table. The method comprises volatizing at least one source material of a sulfide of a pre-determined composition to form a sulfur-bearing thin film composition on a substrate and simultaneously inhibiting any excess quantity of sulfur-bearing species volatilized from the at least one source material from impinging on the substrate. The method improves the luminance and emission spectrum of phosphor materials used for full color ac electroluminescent displays employing thick film dielectric layers with a high dielectric constant.

Abstract: The invention is a thin film phosphor structure that can be processed on a substrate comprising glass or glass ceramic coated with thin film electrode strips at lower temperatures. The improved phosphor structure for use in a thick film dielectric electroluminescent display comprises a phosphor laminate of a blue light emitting phosphor thin film layer and a thin fluoride containing layer provided directly adjacent the phosphor thin film layer, wherein the fluoride containing layer is provided on the top and/or bottom of the phosphor thin film layer.

Abstract: An improved smoothing layer for use with a thick film dielectric layer, and improved composite thick film dielectric structure is provided. The smoothing layer is a piezoelectric or ferroelectric material that has a reduced amount of defects. The smoothing layer is formed by the addition of surfactant to a sol gel or metal organic solution of organo metallic precursor compounds. The composite thick film dielectric structure comprises a thick film dielectric composition having a PZT smoothing layer thereon, the smoothing layer being made by a process incorporating surfactant. Both the smoothing layer and the composite thick film dielectric structure are for use in electroluminescent displays.

Abstract: An extended area uniform light source providing uniform luminance is taught for displays and other applications where the light emission can be planar or have curvature. The uniform light source is achieved using a combination of a blue light-emitting electroluminescent layer and a highly stable inorganic photoluminescent colour conversion layer to tailor the colour spectrum of the emitted light. The invention thus encompasses the uniform light source, displays incorporating the uniform light sources as well of methods of making such light sources and displays.

Abstract: A driving circuit for driving a display panel having pixels arranged in rows and columns, wherein the driving circuit incorporates a resonant circuit that is able to efficiently recover capacitive energy stored on the row of pixels and transfer it to another row of pixels as the rows are addressed by the sequential application of a voltage on each row. The resonant circuit comprises a step down transformer, a capacitor across the primary winding, either the rows or columns of the display panel connected across the secondary winding and an input voltage and FET switches to drive the resonant circuit synchronous with the timing pulses governing the addressing of the display. The value of the capacitor connected across the transformer primary winding is chosen commensurate with the turns ratio on the transformer and the anticipated range of panel capacitance values to effectively limit variations in the resonance frequency with respect to the frequency of the timing pulses.

Abstract: An improved color-converting photoluminescent film that provides visible light emission in the red to green portion of the visible spectrum when excited by blue light. The color-converted photoluminescent film of the invention is patternable and has improved luminous efficiency and stability and is suitable for use in electroluminescent displays. The film comprises a mixture of a clear UV curable resin and photo-initiator which does not absorb blue light; and fluorescent pigment particles, wherein a molecular additive is optionally provided in to either or both of the pigment particles and curable resin. The mixture is screen printed onto a substrate to form a film and UV cured.

Abstract: A physical vapor deposition method for the deposition of thioaluminate phosphor compositions includes providing one or more source materials including an intermetallic barium aluminum compound, a barium aluminum alloy or a protected barium metal, providing an activator species and effecting deposition of the one or more source materials and activator species as a phosphor composition on a selected substrate. The method allows for the deposition of blue thin film electroluminescent phosphors with high luminance and colors required for TV applications.

Abstract: A thin film phosphor for an electroluminescent device, the phosphor being selected from the group consisting of thioaluminates, thiogallates and thioindates having at least one cation selected from elements of Groups IIA and IIB of the Periodic Table of Elements. The phosphor being activated by a rare earth metal and containing oxygen as a partial substitute for a portion of the sulphur in the crystal lattice of the thiogallate, thioindate or thioaluminate. The phosphor is a single phase homogeneous compound and provides improved luminance stability. An electroluminescent device comprising the thin film phosphor is also described and methods of making the phosphor of the invention.