A Nonlinear Random Coefficients Model for Degradation Testing

As an alternative to traditional life testing, degradation tests can be effective in assessing product reliability when measurements of degradation leading to failure can be observed. This article presents a degradation model for highly reliable light displays, such as plasma display panels and vacuum fluorescent displays (VFDs). Standard degradation models fail to capture the burn-in characteristics of VFDs, when emitted light actually increases up to a certain point in time before it decreases (or degrades) continuously. Random coefficients are used to model this phenomenon in a nonlinear way, which allows for a nonmonotonic degradation path. In many situations, the relative efficiency of the lifetime estimate is improved over the standard estimators based on transformed linear models

Flat Panel Displays in an Automotive Environment

A study was made of the field of flat panel displays, and their potential application in an automotive environment. Using contemporary display technology, semiconductors and software, a model was developed to fit an existing automotive instrumentation application. The resulting model was critically assessed in respect to the demands of such an application in respect to existing instrumentation methods. The viability and suitability of implementing such a design are discussed as well as its ability to be intrinsically portable and adaptable

Degradation Models

Reliability testing typically generates product lifetime data, but for some tests, covariate information about the wear and tear on the product during the life test can provide additional insight into the product’s lifetime distribution. This usage, or degradation, can be the physical parameters of the product (e.g., corrosion thickness on a metal plate) or merely indicated through product performance (e.g., the luminosity of a light emitting diode). The measurements made across the product’s lifetime are degradation data, and degradation analysis is the statistical tool for providing inference about the lifetime distribution from the degradation data

Displays: Market and Technologies

Displays provide the essential human interface to virtually all electronics instrumentation. The market is large with new applications appearing every year; sometimes with profound impact. Digital watches with liquid crystal displays appeared in the early 1970s and have virtually wiped out the mechanical timepiece industry. Personal computers with cathode ray tube (CRT) displays are proliferating with diverse applications in the industry and in the home. Work stations with high-resolution color displays are changing the way architects, draftsmen, and IC designers perform their job. The CRT is the dominant technology in today\u27s market, and will, no doubt, continue to be for some years to come. High-resolution shadow-mask tubes will capture a larger and larger market share in the coming years. Projection displays will grow rapidly with the introduction of systems based on new technologies and with the advent of high definition TV. The flat panel industry is growing at 30 percent per year, not so much from taking business away from CRTs, as in the creation of new applications. This is an area rich in technologies with many contenders such as plasma, electro-luminescence, liquid crystal, vacuum fluorescent, electro-chromic, and others

Afterglow, TL and OSL properties of Mn2+-doped ZnGa2O4 phosphor

The work was supported by Latvian Research Council via LZP-2018/1–0214 research project as well as the Latvian-Ukrainian Joint Research Project (LV-UA/2016/1 in Latvia and M/8-2018 (No. 0118U001672) in Ukraine), and by the NATO SfP Project G4649. The work was also partially supported by the Polish National Science Center (project 2018/31/B/ST8/00774). A. Luchechko gratefully acknowledges a grant from Institute of Physics PAS for a research visit to the Institute.Zinc gallate (ZnGa2O4) spinel ceramics doped with Mn2+ ions was prepared by a solid-state reaction at 1200 °C in air. Manganese concentration was equal to 0.05 mol.% of MnO with respect to ZnO. Ceramics produced in this way show an efficient green emission at about 505 nm under UV or X-ray excitations, which is caused by Mn2+ ions. This green emission is observed also as a relatively long afterglow (visible to the naked eye in the dark for about one hour) after switching-off the X-ray excitation. Time profiles of the beginning of glow and afterglow have been studied together with thermally stimulated (TSL) and optically stimulated (OSL) luminescence. Experimental results demonstrate a presence of few types of shallow and deep traps responsible for the observed afterglow and TSL/OSL emission of the material. The possibility of pulsed optical stimulation and time-resolved OSL characteristics of ZnGa2 O4: Mn2+ has been reported for the first time. The presented results suggest the ZnGa2O4: Mn2+ spinel as a promising material for further fundamental research and possibility of application as a green long-lasting phosphor or storage phosphor for TSL/OSL radiation dosimetry.North Atlantic Treaty Organization G4649; Polish National Science Center project 2018/31/B/ST8/00774; 0118U001672,LV-UA/2016/1,LZP-2018/1–0214; Institute of Solid State Physics, University of Latvia as the Center of Excellence has received funding from the European Union’s Horizon 2020 Framework Programme H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under grant agreement No. 739508, project CAMART

Cathodoluminescent display phosphors

The past several years rendered a resurgence of interest in phosphors for low-voltage flat panel displays utilizing cathodoluminescence (CL). A major selection criterion for these phosphors is CL efficiency. The objective is to maximize the efficiency at low voltages. This work focuses on understanding the materials properties that influence CL efficiency below 1 kV. Existing high-voltage CL efficiency models take into account intrinsic materials properties such as band-gap energy. Experimental data reveals that the CL efficiency also depends on physical properties such as particle and crystallite size. An update, predictive model of CL efficiency that includes the effects of crystallite size, radiative recombination probability, and electron accelerating potential was developed. The predicted efficiencies agree very well with experimental results. The experimental data were collected using a hot filament electron gun in a demountable high-vacuum chamber. To obtain measurement accuracy, secondary electrons were collected and the phosphor excited with a uniform beam profile. A CL characterization protocol for display phosphors was established at Sandia National Laboratories and made available to phosphor researchers

Challenges and opportunities in flat panel industry

The Flexible Panel Display (FPD) business is rapidly growing in Asia. Many industrial companies not only from traditional coating industries but from others such as electronics, printing, and film manufacturing industries, arc coming into this business in Japan, Korea, Taiwan and quite possibly in near future, China because of such a high growth opportunity. The total capital investment announced by several key companies, is several billion dollars for next one to two years. Due to the fact of the application to optical (quality) and consumer (cost) products, we have challenges in web handling technology besides coating and drying technologies. For example, the thin film precision coating, which is crucial for display products, requires the precision web handling, which means, for example, the technologies such as the uniform cross web tension of thin film and the scratch free web handling of wide film are essential.The FPD business will be overviewed and the technological challenges in web handling in combination with coating process will be discussed briefly based on the current and future needs