摘要:
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. The voltage at the ramp termination is held at a constant value and fed to the output buffer of the gray scale drivers for the display columns.
摘要:
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.
摘要:
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.
摘要:
A patterned phosphor structure, and EL laminate containing same, forming red, green, and blue sub-pixel phosphor elements for an AC electroluminescent display. The patterned phosphor structure includes at least a first and a second phosphor emitting light in different ranges of the visible spectrum, but with combined emission spectra contains red, green, and blue light, the first and second phosphors being in a layer, arranged in adjacent, repeating relationship to each other to provide a plurality of repeating first and second phosphor deposits. Photolithographic methods for producing the patterned phosphor structure are also provided. Also provided is an improved dielectric layer for use in an EL laminate, including a pressed, sintered ceramic material having, compared to an unpressed, sintered dielectric layer of the same composition, improved dielectric strength, reduced porosity and uniform luminosity in an EL laminate.
摘要:
A novel structure is provided to improve the luminance and operating stability of phosphors used in ac thick film dielectric electroluminescent displays. The novel structure comprises aluminum nitride barrier layers in contact with the phosphor films to prevent phosphor degradation due to reaction with oxygen. The barrier layers can be deposited using vacuum deposition processes that are compatible with the processes used to deposit and anneal the phosphor films. 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.
摘要:
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.
摘要:
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.
摘要:
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. The present invention is an improvement to the resonant driving circuit that employs column drivers that maximize energy recovery in the resonant circuit by employing a means to restrict current flowing through the FETs used to control the column voltage so that substantially all of the current that flows when charge is being removed from the display pixels during the time period between selection of active rows is constrained to flow back through the transformer to charge the primary capacitor.
摘要:
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.
摘要:
A pixel sub-structure for an electroluminescent display and a method for making the same. The sub-structure comprising: a color conversion layer; and an optical enhancement layer; wherein at least a portion of the color conversion layer is integrated with at least a portion of the optical enhancement layer.