scholarly journals Highly Reflective Thin-Film Optimization for Full-Angle Micro-LEDs

2021 ◽  
Vol 16 (1) ◽  
Author(s):  
Zhi-Ting Ye ◽  
Wen-Tsung Ho ◽  
Chia-Hui Chen
Keyword(s):  
Thin Film ◽  
Light Source ◽  
Low Voltage ◽  
Source Area ◽  
Film Coating ◽  
Light Distribution ◽  
Light Emitting ◽  
Thin Film Coatings ◽  
Voltage Variation ◽  
Commercial Advertising

AbstractDisplays composed of micro-light-emitting diodes (micro-LEDs) are regarded as promising next-generation self-luminous screens and have advantages such as high contrast, high brightness, and high color purity. The luminescence of such a display is similar to that of a Lambertian light source. However, owing to reduction in the light source area, traditional secondary optical lenses are not suitable for adjusting the light field types of micro-LEDs and cause problems that limit the application areas. This study presents the primary optical designs of dielectric and metal films to form highly reflective thin-film coatings with low absorption on the light-emitting surfaces of micro-LEDs to optimize light distribution and achieve full-angle utilization. Based on experimental results with the prototype, that have kept low voltage variation rates, low optical losses characteristics, and obtain the full width at half maximum (FWHM) of the light distribution is enhanced to 165° and while the center intensity is reduced to 63% of the original value. Hence, a full-angle micro-LEDs with a highly reflective thin-film coating are realized in this work. Full-angle micro-LEDs offer advantages when applied to commercial advertising displays or plane light source modules that require wide viewing angles.

scholarly journals Elimination of the blinding effect in landscape luminaires

2018 ◽  
Vol 7 (2.13) ◽  
pp. 252
Author(s):  
Albert Ashryatov ◽  
Dinara Churakova
Keyword(s):  
Light Curve ◽  
Light Source ◽  
Light Flux ◽  
Light Distribution ◽  
Light Sources ◽  
Mirror Surface ◽  
Light Emitting ◽  
Lighting Technology ◽  
Initial Task ◽  
Flat Beam

The article presents one of the possible options for implementing the lighting technology "Flat beam" for landscape lighting purposes. One of the possible ways to control the light distribution of a number of light sources based on LEDs with different radiation patterns is considered. As a secondary optics, it is proposed to use a mirror surface that redistributes the light flux of an LED light source. It is indicated that, depending on the initial type of the light-emitting diodes light curve and the features of mounting the mirror surface, the resulting light distribution can vary widely, depending on the initial task that the designer sets for himself.  

Low Voltage Driven White Light Emitting Thin Film EL Device

1989 ◽  
Vol 114 (2) ◽  
pp. K233-K236 ◽  
Author(s):  
M. K. Jayaraj ◽  
C. P. G. Vallabhan
Keyword(s):  
Thin Film ◽  
White Light ◽  
Low Voltage ◽  
Light Emitting

Structure and Properties of SiC Coated R6M5 High-Speed Steel

2013 ◽  
Vol 594-595 ◽  
pp. 730-734
Author(s):  
Мazhyn Skakov ◽  
Bauyrzhan Rakhadilov ◽  
Gaukhar Karipbayeva
Keyword(s):  
Thin Film ◽  
High Speed ◽  
High Speed Steel ◽  
Film Coating ◽  
Thin Film Coating ◽  
X Ray ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Before And After ◽  
Scanning Electronmicroscopy

A Possibility of R6M5 High-Speed Steel Strengthening by Finishing Plasma Strengthening(FPS) Method to Application of Sic Thin Film Coatings were under Research. by Scanning Electronmicroscopy and X-Ray Analysis Conducted a Comparative Study of the Structure, Phase and Chemicalcomposition before and after Application of Sic Thin Film Coating of R6M5 High-Speed Steel Surfacelayer. it is Experimentally Stated, that the Coverage of Sic Applied Method FPS Consists of Fineglobular Shape at the Size of 100-300 Nm. Determined that the Microhardness of R6M5 Steel Surfaceafter Application Sic Coating Increased Almost to 2.5 Times Comparing to Original. it is Shown Thatthe Application of Sic Thin Film Coating by FPS Method is a Promising Highly Effective Method Ofcutting Tools Surface Strengthening Made from High Speed Steels.

The Oxidation Stability of Boron Nitride Thin Films on MgO and TiO2 Substrates

1991 ◽  
Vol 250 ◽  
Author(s):  
Xiaomei Qiu ◽  
Abhaya K. Datye ◽  
Robert T. Paine ◽  
Lawrence. F. Allard
Keyword(s):  
Thin Film ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Oxidation Stability ◽  
Film Coating ◽  
Thin Film Coating ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Transmission Electron ◽  
The Stability

AbstractThe stability of BN thin film coatings (2–5 nm thick) on MgO and TiO2 substrates was investigated using transmission electron microscopy (TEM). The samples were heated in air for at least 16 hours at temperatures ranging from 773 K - 1273 K. On MgO supports, the BN thin film coating was lost by 1073 K due to a solid state reaction with the substrate leading to formation of Mg2B2O5. No such reaction occurred with the TiO2 substrate and the BN was stable even at 1273 K. However, the coating appeared to ball up and phase segregate into islands of near-graphitic BN and clumps of TiO2 (rutile). The oxidizing treatment appears to promote the transformation from turbostratic BN to graphitic BN.

Bio-Derived Bone Surface Modification with Biomimetic Thin Film Coatings to Improve Mesenchymal Stem Cells Adhesion and Spreading

2008 ◽  
Vol 373-374 ◽  
pp. 722-725 ◽  
Author(s):  
Ke Dong Song ◽  
Peng Fei Wen ◽  
Tian Qing Liu
Keyword(s):  
Thin Film ◽  
Stem Cells ◽  
Bone Marrow ◽  
Mesenchymal Stem Cells ◽  
Cell Adhesion ◽  
Film Coating ◽  
Thin Film Coating ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Marrow Mesenchymal Stem Cells

Initial attachment and spreading of the inoculated cells determines the long-time viability of cells onto biomedical scaffolds designed for various orthopedic or other clinical applications. The aim of this study was to investigate the influence of biomimetic thin film coating surfaces of bio-derived bone scaffolds with collagen proteins and chitosan on bone marrow mesenchymal stem cells interactions in order to improve cell adhesion, spreading and proliferation. These two merits were used synthetically to generate apatite-based materials that can function as allograft bone grafts in humans. In this study, the thin film coatings were operated by means of soaked, pre-frozen, and freeze-dried step by step. All coatings were characterized using Raman spectra, inverted microscope, atomic force microscopy, and scanning electron microscopy. After that, the bio-derived bone scaffolds with or without thin film coatings were used in bone marrow mesenchymal stem cell culture experiments to study cell adhesion, spreading, viability, proliferation and morphology. Then, the biological morphologies of the fabricated cell-scaffold constructs were detected by scanning electron microscope (SEM). The cell reactions were investigated concerning cell adhesion, migration, spreading, and proliferation under inverted microscope and fluorescence microscopy. The results showed that the bio-derived bone scaffold treated with thin film coatings by using rat-tail type I collagen and chitosan improved the adhesion and spreading of mesenchymal stem cells in comparison to the untreated one. Besides, cell viability and morphology were not affected by the presence of either type of thin film coating. Still, the results assay revealed an increased proliferation of bone marrow mesenchymal stem cells on both types of thin film coatings compared to coating with non-coated controls.

Prolonging the Lifetime of PEEK Packages for Implantable Electronic Devices Using Commercially Available Vacuum Thin Film Coatings

2014 ◽  
Vol 11 (3) ◽  
pp. 128-136
Author(s):  
Nathaniel Dahan ◽  
Nick Donaldson ◽  
Stephen Taylor ◽  
Nuno Sereno
Keyword(s):  
Thin Film ◽  
Vapor Deposition ◽  
Physical Vapor Deposition ◽  
High Surface ◽  
Chemical Vapor ◽  
Atomic Layer ◽  
Film Coating ◽  
Internal Cavity ◽  
Thin Film Coatings ◽  
Uniform Wall

For short term applications (less than three years), it may be possible to replace traditional long term packaging materials such as titanium with a biocompatible polymer such as PEEK. This paper investigates the use of commercially available thin films to decrease the water vapor permeation rate through the walls of a PEEK package. It was found that most physical vapor deposition (PVD) and plasma assisted chemical vapor deposition (PaCVD) coatings tested did not provide a significant improvement in lifetime, due to the porosity of the films produced. This is mostly linked to the morphology of the films (i.e., growth in columns which are poorly bonded together, creating a porous structure) and is exacerbated by the high surface roughness of the machined substrates. Applying a lacquer before coating reduces this effect significantly, and we found that the time constant of our coated packages was improved by a factor of 2.3. Based on the findings of our group's previous work and this paper, the maximum achievable lifetime of PEEK packages with a thin film coating and desiccant is presented. As an example, a coated cylindrical PEEK package (using atomic layer deposition, ALD) with a uniform wall thickness of 2 mm, an internal cavity size of 1.5 cm3, filled with 20% of desiccant, has a lifetime of 18.8 mo (27.2 mo with 30% of desiccant). This would be sufficient for a range of applications and provide a cheaper and more versatile packaging alternative to traditional packages.

A Comparative Study on the Hardness of CrN, CrC and CrCN Coatings

2014 ◽  
Vol 1016 ◽  
pp. 145-149 ◽  
Author(s):  
Supakanya Khanchaiyaphum ◽  
Charnnarong Saikaew ◽  
Parinya Srisattayakul ◽  
Naphatara Intanon
Keyword(s):  
Thin Film ◽  
Surface Quality ◽  
High Hardness ◽  
Film Coating ◽  
Machine Component ◽  
Thin Film Coating ◽  
Thin Film Coatings ◽  
Part Surface ◽  
Hardness Values

Improving the surface quality of various machine components can extend their lifespans by several orders of magnitude. Thin film coating is one approach that can be used to enhance machine part surface quality. In this work, three different thin film coatings (i.e, CrN, CrC and Cr-C-N) were statistically compared for surface quality improvement of fishing-net weaving machine component, namely an upper hook. All coatings were deposited utilizing DC sputtering technique. The effects of coating types on hardness for both hardchrome and non hardchrome coated upper hooks were systematically investigated using one-way analysis of variance (ANOVA). Scanning electron microscope (SEM) and energy dispersive X-ray (EDX) were used to examine the surface quality of the machine component. This study found that CrN gave very high hardness values of 13.042 GPa for hardchrome coated upper hooks and 12.583 GPa for non-hardchrome coated upper hooks. However, the averages hardness of the hardchrome coated and non-hardchrome coated upper hooks were not significantly different at the 95% confidence level.

scholarly journals Thin film coatings material particles creation by pulsed methods in vacuum

2021 ◽  
Vol 2059 (1) ◽  
pp. 012017
Author(s):  
Y V Panfilov ◽  
L L Kolesnik ◽  
A V Gurov
Keyword(s):  
Thin Film ◽  
Ion Beam ◽  
Film Coating ◽  
Laser Deposition ◽  
Vacuum Arc ◽  
Pulsed Discharge ◽  
Thin Film Coating ◽  
Film Coatings ◽  
Thin Film Coatings ◽  
Nanocrystalline Thin Film

Abstract Thin film materials particles creation pulsed methods such as magnetron sputtering HiPIMS, pulsed laser deposition PLD, vacuum arc pulsed discharge, high-intensity pulsed ion beam impact HIPIB, as well, were described. It was shown that the stream of material, created by means of an explosion action such as ablation, avalanche paired impacts and microsecond electrical disruption as well creates preconditions for nanocrystalline thin film coating manufacture.

scholarly journals Optical System for Led Luminaire

2019 ◽  
pp. 62-67
Author(s):  
A. Kolesnyk
Keyword(s):  
Light Source ◽  
Light Emitting Diodes ◽  
New Technology ◽  
Light Distribution ◽  
Optical Systems ◽  
Light Sources ◽  
Optical Elements ◽  
Light Emitting ◽  
The Right ◽  
Led Luminaire

Lighting devices are an important element of a large number of technical systems, including road, living, industrial lighting, lighting systems of vehicles. It is known that the light instrument must fulfill two basic lighting tasks: to redistribute the light source of light source in the right way and to limit its dazzling effect. The introduction of light-emitting diodes (LEDs) for lighting necessitated a completely new quality in the construction of luminaires. The different production technology required new methods and designing tools. It also challenged designers with new problems to solve. LEDs are light sources emitting in one hemisphere, which requires a special approach to designing an LED lighting unit. However, for the illumination of premises with high spans or streets, roads such a light distribution is not suitable. For luminaires with solid-state light sources, other materials and new technology must be used; moreover, light distribution needs to be formed using different methods. This paper presents the design process of a LED luminaire from concept to implementation, exemplified by road lighting, and describes the methods and procedures used by the designer. Also, technological problems influencing the quality of the above lighting are addressed. Optical systems for LEDs are considered. The peculiarities of the use of secondary optical elements in the form of lenses for purpose of obtaining different diagrams of the spatial distribution of light intensity of light-emitting diodes are analyzed. Features and problems of calculation of secondary optical systems are considered. Massive collimators do not have to be elements that focus a narrow beam of light. They are able to form a beam in accordance with any accepted distribution that is appropriate for a given application. They are also able to form a beam in a specific way that is required for outdoor lighting luminaires. The stages of a project for designing a road luminaire require the application of the knowledge and experience gained in various research projects. The design methods described in this paper have been developed designing activity and are also to be used successfully in lighting production.  

scholarly journals Effective Light Source for Illuminating Overhead Guide Signs and Improving Roadway Safety

2016 ◽  
Author(s):  
Mohammed S. Obeidat ◽  
Malgorzata J. Rys
Keyword(s):  
Cost Analysis ◽  
Light Source ◽  
Light Emitting Diode ◽  
Operating Cost ◽  
Mercury Vapor ◽  
Light Distribution ◽  
Light Sources ◽  
Good Efficiency ◽  
Light Emitting ◽  
Roadway Safety

Driver safety is considered an important issue to departments of transportation. One way to increase highway safety is to improve the visibility of overhead guide signs for drivers. Visibility improving methods include the use of sign illumination or retroreflective sheeting materials. This paper focuses on sign illumination by comparing five light sources including high pressure sodium (HPS), metal halide (MH), mercury vapor (MV), induction lighting, and light emitting diode (LED). A laboratory experiment was conducted to compare effective light distribution of each light source and a cost analysis was performed to compare initial, maintenance, and operating cost components of the light sources. Results of the light distribution experiment indicated that HPS was the optimum light source followed by MH, induction lighting, MV, and LED. Induction lighting is a promising lighting technology which features good efficiency and long life. According to cost analysis, induction lighting was the most effective source, followed by the LED, HPS, MV, and MH. Of the five light sources considered, induction lighting provided the best overall performance when considering initial cost, operating cost, expected maintenance, and sign illuminance. Environmentally, LED does not contain mercury, and for those agencies that prefer using sources that are friendlier with the environment, the LED can be their best choice.

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