Browse Topic: Light emitting diodes (LEDs)
Passive fatigue can cause accidents with automated and regular vehicles. A proof-of-concept prototype [made with light-emitting diode (LED) matrices and white LED (WLED)] and a preliminary comparative usability test (N = 7) are used to study whether the active manipulation of simulated weather cues can be a potential countermeasure to passive fatigue. Participants rated system suitability, system impression, and their fatigue level similarly when they viewed a weather windshield heads-up display (HUD) versus a speedometer windshield HUD [no significant differences found and relatively small 95% confidence interval (CI) ranges around 0]. Qualitative analysis of interviews found that participants saw the potential value of the weather display and that display placement, dynamic graphics, and user activation were commonly mentioned themes. These results suggest the concept is theoretically possible, though further work is needed to prove the concept in practice.
A demonstration ride shows the glare-free, game-changing power of adaptive driving beams, already available in Europe. An approval test from NHTSA is proving difficult for OEMs to pass. I'm riding in the second row of a Lincoln Navigator fitted with Forvia Hella's adaptive driving beam (ADB) headlight system. The low- and high-beams are on, blasting everything in front of us for between 350 and 500 feet (122 and 152 m) with a bright, daylight-temperature LED light. Even traffic and street signs at the edges of the road, which normally aren't as well illuminated, are bathed in brightness. A car pulls out in front of us, and the system instantly adjusts, creating a tunnel of unlit space on and just next to the vehicle ahead. So even though we still have high beams on the rest of the road, that driver isn't facing the harsh glare that is the No. 1 complaint about today's high-intensity headlight systems.
The objective of this study was to examine the effect of Correlated Colour Temperature (CCT) of automotive LED headlamps on driver’s visibility and comfort during night driving. The experiment was conducted on different headlamps having different correlated colour temperatures ranging from 5000K to 6500K in laboratory. Further study was conducted involving participants of different age group and genders for understanding their perception to identify objects when observed in light of different LED headlamps with different CCTs. Studies have shown that both Correlated Colour Temperature and illumination level affect driver’s alertness and performance. Further study required on headlamps with automatically varying CCT to get better solution on driver’s visibility and safety.
This document establishes training guidelines applicable to fiber optic safety training, technical training and fiber awareness for individuals involved in the manufacturing, installation, support, integration and testing of fiber optic systems. Applicable personnel include: Managers Engineers Technicians Logisticians Trainers/Instructors Third Party Maintenance Agencies Quality Assurance Shipping Receiving Production Purchasing
This document establishes training guidelines applicable to fiber optic fabricator technical training for individuals involved in the manufacturing, installation, support, integration and testing of fiber optic systems. Applicable personnel include: Managers Engineers Technicians Trainers/Instructors Third Party Maintenance Agencies Quality Assurance Production
Researchers have developed a prototype imaging system that could significantly improve doctors’ ability to detect cancerous tissue during endoscopic procedures. This approach combines light-emitting diodes (LEDs) with hyperspectral imaging technology to create detailed maps of tissue properties that are invisible to conventional endoscopic cameras.
Boosting the performance of solar cells, transistors, LEDs, and batteries will require better electronic materials, made from novel compositions that have yet to be discovered.
Thermal nondestructive evaluation (NDE) is a widely used method for detecting defects such as cracks, corrosion, and dis-bond layers in metallic and composite structures. Traditional thermal inspection methods rely on a high-intensity, broadband light heat source (e.g., flash lamp, quartz lamp) that generates heat that is absorbed by the material, and an infrared camera captures the transient thermal response to generate inspection data. However, inspecting low emissivity surfaces (such as unpainted aluminum and titanium alloys) poses challenges including high reflection of the heat source light that can cause inaccurate measurement of the surface temperature response, produce false defect indications, and potential sensor damage due to high-intensity reflections.
Researchers have developed a gel polymer-based triboelectric nanogenerator (TENG) that generates electrical signals from body movement to power electronics like LEDs and functions as a self-powered touch panel for user identification. The device can stretch up to 375 percent of its original size and withstand rigorous mechanical deformations, making it suitable for wearable applications. TENGs that convert mechanical energy such as body movement to electrical energy offer a solution to power wearable devices without relying on batteries.
A thin film that combines an electrode grid and LEDs can both track and produce a visual representation of the brain’s activity in real time. The device is designed to provide neurosurgeons visual information about a patient’s brain to monitor brain states during surgical interventions to remove brain lesions including tumors and epileptic tissue.
A new type of organic light emitting diode (OLED) could replace bulky night vision goggles with lightweight glasses, making them cheaper and more practical for prolonged use, according to University of Michigan researchers.
From televisions to smartphones, organic light-emitting diodes (OLEDs) are finding their way into many everyday devices. For use in displays, blue OLEDs are also required to supplement the primary colors — red and green. Especially in blue OLEDs, impurities give rise to strong electrical losses, which could be partly circumvented by using highly complex and expensive device layouts.
To ensure adequate visibility without excessive glare, vehicle headlights are designed to use a specific source of illumination. The optical designs of headlights gather the luminous flux produced by the light source to produce a useful beam pattern that meets the relevant requirements and standards for vehicle forward lighting. With the advent of solid state, light emitting diode sources for general illumination, an increasing number of LED replacement headlight bulb products has emerged over the past decade. In most cases, these LED replacement bulbs are not permitted for legal use on public roadways, but some countries have begun to permit specific LED replacement bulbs to be used legally on the road for specific makes, models and production years of certain vehicles. If they can be demonstrated to produce a beam pattern that meets the photometric requirements for a legal headlight, they are permitted to be used legally for on-road use. In the present paper we present photometric measurement data for two North American headlight systems originally designed for halogen bulbs. Each was fitted with a halogen bulb and with two different LED replacement bulbs and measured at specific angles to check photometric compliance with the minimum and/or maximum luminous intensity at those angles. We also present data on the illuminances produced at several locations along a hypothetical roadway to compare performance between the headlights with halogen bulbs and with each LED bulb.
A research team led by Lawrence Berkeley National Laboratory (Berkeley Lab) has developed “supramolecular ink,” a new technology for use in OLED (organic light-emitting diode) displays or other electronic devices. Made of inexpensive, Earth-abundant elements instead of costly scarce metals, supramolecular ink could enable more affordable and environmentally sustainable flat-panel screens and electronic devices.
A single strand of fiber has the flexibility of cotton and the electric conductivity of a polymer, called polyaniline. The newly developed material showed good potential for wearable e-textiles. Researchers tested the fibers with a system that powered an LED light and another that sensed ammonia gas.
Trends in automotive lighting are moving toward vehicle exterior lights, which will communicate with drivers and surroundings. The small size, lower power consumption, high efficiency, and substantially long life make LEDs a leading light source in automotive lighting applications. Losses in optical power for InGaN-based LEDs can be reduced up to 45% compared to AlGaInP, and phosphor-converted color LEDs can contribute to stable light output over the lifetime. Color LEDs will fulfill different requirements such as uniformity in color and luminance. Additionally, the mixing of different colors with white will underline the exterior features and aesthetic design of vehicles.
Researchers from the Disruptive & Sustainable Technologies for Agricultural Precision (DiSTAP) and the Critical Analytics for Manufacturing Personalized-Medicine (CAMP) Interdisciplinary Research Groups (IRG) of the Singapore-MIT Alliance for Research and Technology (SMART), MIT’s research enterprise in Singapore, have developed the world’s smallest LED. It enables the conversion of existing mobile phone cameras into high-resolution microscopes. Smaller than the wavelength of light, the new LED was used to build the world’s smallest holographic microscope, paving the way for existing cameras in everyday devices such as mobile phones to be converted into microscopes with modifications to the silicon chip and software. This technology also represents a significant step forward in the miniaturization of diagnostics for indoor farmers and sustainable agriculture.
Batteries and humans like to be at room temperature. Thermal-management systems make sure that happens - while maximizing efficiency. When General Motors unveiled the 2025 Cadillac Escalade IQ, the EV luxury SUV with a 24-module Ultium battery pack providing more than 200 kWh of energy that contributes to an estimated 450 miles (724 km) of range and up to 750 hp, the company enumerated an array of technology features, ranging from the 55-in. total diagonal LED display powered by the Qualcomm Snapdragon Platform to the Four-Wheel Steer capability, which reduces the turning diameter of the SUV by more than 6.5 feet (to 39 ft, 4 ins). And there is a suite of other features. But among all that there was another feature perhaps not as glamorous as the sort of equipment in a luxury EV that will sticker at an estimated $130,000: a heat pump.
Imagine a thin, digital display so flexible that you can wrap it around your wrist, fold it in any direction, or even curve it over your car’s steering wheel. Well, imagine no more — researchers at the Pritzker School of Molecular Engineering (PME) at the University of Chicago have designed such a material; it can even bend in half or stretch to more than twice its original length — and still emit a fluorescent pattern.
Researchers have designed a thin, digital display that can bend in half or stretch to more than twice its original length while still emitting a fluorescent pattern. The material has a wide range of applications, from wearable electronics and health sensors to foldable computer screens.
More pixels! This is a major trend in the display industry. The benefits of 8K or higher resolution TVs may be debatable. For eye catching applications such as AR/VR glasses, more and therefore smaller pixels are required for technical feasibility. Screen door effects and pixel inhomogeneities are easily visible and disturbing for the user on displays that sit closely to the viewer’s eye. μ-LEDs are considered an innovative technology for very high resolutions with pixel sizes of less than 10 μm and equally small pixel pitches. In general, they have the potential to be a groundbreaking display technology – provided production challenges can be solved. Just like OLED displays, μ-LEDs are an emissive display technology, i.e., each single subpixel is in itself a light source. Luminance and color variations between the individual pixels are likely. As this strongly influences the visual quality of the displays, a quality control and calibration of the displays is necessary not only in the laboratory, but especially in the production lines. The race for very high resolutions thus places increased demands not only on display manufacturers, but also on the suppliers of light measurement technology.
A research team from the National University of Singapore (NUS) Faculty of Science, led by Professor Liu Xiaogang from the Department of Chemistry, has developed a 3D imaging sensor that has an extremely high angular resolution — it can distinguish points of an object separated by an angular distance, of as little as 0.0018°. The sensor operates on a unique angle-to-color conversion principle, allowing it to detect 3D light fields across the X-ray to visible light spectrum.
Super-cooled large drops present serious threats to aviation safety and as a result, the problem has been addressed by the FAA with the additional icing certification requirement. SLD clouds often consist of bi-modal drop size spectra leading to great challenges when it comes to simulating and characterizing these conditions in situ and in icing wind tunnels. Legacy instrumentation for measuring drop size distributions and liquid water content has been challenged under these conditions. In this report, a high-resolution particle imaging instrument is described; this instrument addresses the need for measuring drop size distributions and liquid water content over a wide range of drop sizes (10 to 2500 μm or larger). A high-throughput megapixel digital camera is used to record shadow images of the particles. High-quality illumination of the particle field is provided with high-power LED illumination with driving electronics designed to provide pulse durations as short as 25ns with sufficient fluence. Image processing software has been developed to enable automated setup of the instrument, image acquisition and processing, and efficient storage of the particle images. Calibration methods regarding the dependence of the depth-of-field to drop size were developed to enable sampling statistics bias corrections due to variations in the sample volume. Measurements acquired in the NASA Icing Research Tunnel (IRT) are provided as an example of the measurement capabilities of the newly developed instruments.
As LEDs replace traditional lighting systems, they bring more smart capabilities to everyday lighting. While you might use your smartphone to dim LED lighting at home, researchers have taken this further by tapping into dynamically controlled LEDs to create a simple illumination system for 3D imaging.
Headlamps should illuminate the traffic scene ahead of the vehicle in such a way that the driver can operate the vehicle safely and in a relaxed manner. At the same time, negative effects on drivers of other vehicles, pedestrians and other people should be minimized. Various technical parameters such as beam pattern, mounting height, headlamp aiming, and source spectrum can be tuned to find the necessary compromise. The physiology of the vision system under specific nighttime conditions strongly influences these factors and how headlamps can be best optimized for visibility and comfort. The SAE Improved Roadway Illumination task force collected and reviewed relevant research on these topics. This document is a comprehensive summary of this information. The goal is to enable lighting experts, advocacy groups, and non-experts (journalists, consumer organizations, car drivers) to better understand the benefits and tradeoffs of improved roadway lighting with modern headlamp technology. It should be noted that all studies cannot be included in this report, but the intent of this document is to provide the reader with a representative sample of the existing research as a starting point. Further, this document can be updated in the future to reflect new research findings.
The ability to control light using a semiconductor device could allow low-power, relatively inexpensive sources like LEDs or flashlight bulbs to replace more powerful laser beams in new technologies such as holograms, remote sensing, self-driving cars, and high-speed communication.
Army Research Laboratory, Adelphi, MD Developing single photon UV detection for compact chemical and biological sensors. This report summarizes the main lines of effort for the Electro-Optics Materials Research (EOMR) program including its goals and major accomplishments, focusing on the past 5 years. This EOMR program was an effort within 601102A.31B.1 titled “Optoelectronic and Integrated Photonic Materials and Device Research” for FY16-FY19 and 611102A.AA8.1 titled “Photonic Materials and Device Research” for FY20-FY21. The focus of this EOMR for most of the program was to develop novel semiconductor optoelectronic devices to reduce the size, weight, power, and cost (SWaP-C) of chemical and biological detection and identification systems. Specifically, the program addressed the need for high sensitivity photodetectors in the near-UV (NUV) spectrum between 300 and 350 nm for biological agent detection using light-induced fluorescence techniques employed by the Tactical Biological (TAC-BIO) detector, developed by the US Army Combat Capabilities Development Command Chemical Biological Center, as well as in the deep UV spectrum (220-240 nm) important for standoff chemical detection based upon fluorescence-free Raman spectroscopy. Late in the program, this effort pivoted to address assured communications challenges relevant to the Army modernization priority for future networks through examining how to improve the efficiency of solar-blind UV LEDs.
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