European market surveillance authorities investigated the safety and compliance of LED bulbs with a joint control project. Indeed, 47% of the products were removed from the European market as non-compliant.

Of the 82 LED floodlights tested, only two met the technical and administrative requirements of both legislation. As a result of the project, 47% of the tested LED spotlights were pulled out of the EU market. A total of 87 floodlights were tested for electrical safety requirements. 87 per cent of the tested products did not meet the requirements. Indeed, 71 percent of the products had flaws that could endanger the user’s safety.

Tukes closely monitored the ten LED spotlights sold in Finland, of which five were withdrawn from the market

Source: https://www.uusiteknologia.fi/2017/09/12/led-valonheittimista-loytyi-paljon-puutteita/

How may photons does a LED emit at very low currents?
What is the lowest current where a LED will actually emit photons? Dave does some measurements to answer this quantum physics level stuff!

This light was donated for teardown by http://www.banggood.com and you can find it listed here:- http://bit.ly/1HVMS8B

There are a lot of things I like about this light. It has a good robust case with a glass front and thick seal. The LEDs are plain 1W beads on a well spread out mounting panel with plenty of heatsink compound between it and a chunky finned exterior heatsink. The temperature on the heatsink only rose about 20C above ambient, which is very good. The LEDs are also driven in a continuous series string at 300mA

Our new house is inching towards 100% LEDness, from LED “bulbs” in standard light fixtures, to custom LED lighting, to flexible LED light strips. It’s the latter I’m having some problems with.

After some preliminary research, I decided that the only affordable sources for LED strips would be from among the numerous Shenzhen & Hong Kong mega-retailer Websites. There, you’ll find standard 5m LED strips in the $4-$20 range, instead of the $50-$100 range typical of other sources.

After some preliminary research, I decided that the only affordable sources for LED strips would be from among the numerous Shenzhen & Hong Kong mega-retailer Websites. There, you’ll find standard 5m LED strips in the $4-$20 range, instead of the $50-$100 range typical of other sources.

With the LEDs themselves taken care of, I turned to power sources. In the basement, I’ll probably use some centralized high current 12V power supplies..

While I’m willing to accept some creative LED specs, I do expect a 5A adapter to be a 5A adapter. Silly me. They turned out to be more like 2A, and to add insult to injury, the output cables appeared to be vastly undersized

LED lights increase in everyday life can negatively affect the vision and dream, writes the Financial Times . LED lights are used a lot, especially smart devices and consumer electronics.

According to the newspaper more than once, the study has revealed worrying signs that the exposure to the LED lights may cause long-term age related macular degeneration. According to FT that it is the most common cause of blindness in the Western world.

A Spanish study found that LED light may destroy the eye tissues of several 12-hour exposure.

The results are still preliminary, but they raise questions about the LED lights effects.

FT: According to macular degeneration causes specifically the blue part of sunlight. Yale University School of professorfin Ron Adelman, the macular degeneration is more common in the northern parts of the world living in people. Blue light is more intense LED lights than incandescent lamps. It is estimated that in European countries led and fluorescent lights completely replace incandescent light bulbs by 2016.

Studies have also found that the blue light interferes with sleep. THL’s senior researcher Erkki Kronholm evaluate the new Finland in November , that the increased use of electronic devices may appear young sleep problems increase.

- 90 since the beginning, more and more young people have started to use computers, game consoles, smart phones and other similar electronic devices in the evenings. Their light affects the nerve center, for example, in the evenings playing activates the psycho-physically, making it difficult to calm down. Sleep disorders correlated with an increase in the use of equipment with Kronholm said.

Source: http://www.uusisuomi.fi/tiede-ja-ymparisto/75995-led-valoilla-ikava-seuraus-huolestuttavia-merkkeja

Effects of light-emitting diode radiations on human retinal pigment epithelial cells in vitro.
http://www.ncbi.nlm.nih.gov/pubmed/22989198

Human visual system is exposed to high levels of natural and artificial lights of different spectra and intensities along lifetime. Light-emitting diodes (LEDs) are the basic lighting components in screens of PCs, phones and TV sets; hence it is so important to know the implications of LED radiations on the human visual system. The aim of this study was to investigate the effect of LEDs radiations on human retinal pigment epithelial cells (HRPEpiC). They were exposed to three light-darkness (12 h/12 h) cycles, using blue-468 nm, green-525 nm, red-616 nm and white light.

It is shown that LED radiations decrease 75-99% cellular viability, and increase 66-89% cellular apoptosis. They also increase ROS production and DNA damage.

Nuventix and Digi-Key introduces Synjet® Coolers used in LED lighting. Synjet® Coolers have an oscillating diaphragm, high velocity air flow or pulls air in its wake, and turbulent airflow.

Today’s LED lighting devices are expected to perform reliably outdoors and indoors in industrial, commercial, consumer, residential, and architectural settings. These lights must stay bright for more than 36,000 hours, despite exposure to extreme temperatures, dust, dirt, and vibration and even in cases of underwater submersion.

The core of a white solid-state lighting (SSL) luminaire device is the LED (light-emitting diode). The LED is typically a metal-doped silicone carbide chip with a phosphorous layer. The phosphorus changes the typical blue light emitted by the die into whiter, warmer light colors. This assembly is attached to a substrate material and covered with a silicone encapsulant to protect the die and effectively transmit light.

For the manufacturer, adhesives, sealants, potting materials, and threadlockers bond and seal the LED assembly onto the associated substrates and enclosures, lowering manufacturing costs of the lighting assembly and helping ensure the long life of the LED.

But chemical interactions between the materials used in LED production can degrade the light emitted by the encapsulated chip. For example, when adhesives and sealants outgas, they release VOCs into the LED assembly. These VOCs cause the LEDs in the light modules to discolor, reducing the clarity and brightness of the LED light. This is especially common in closed systems, where the space between the chip, the silicone lens, and the external cover lens is a sealed environment with no ventilation to the outside atmosphere.

In a closed environment, the VOCs have nowhere to escape. Trapped organics migrate into the silicone lens and make contact with the LED die. If an incompatibility exists between the LED and VOCs, the LEDs discolor rapidly, often within hours of exposure. Light output levels drop and changes in the quality of the light’s color or chromaticity occur. In extreme cases the device can fail completely

LED discoloration is typically not permanent and can be reversed by removing the external cover lens or venting the closed system to release the VOCs.

By specifying only adhesives and sealants that meet compatibility requirements, LED manufacturers can eliminate these materials as a source of browning and help maintain the color point and consistent quality of their lighting devices. Careful adhesive selection during device design ensures that any incompatibilities between LEDs and adhesives never occur.

There’s a new high-density class of CXA arrays from Cree that doubles the lumen density for next-gen LED spotlights. The CXA 1520 is the first HD Array announced under the breakthrough technology.

Applications from general purpose floods to specialty retail spot lights will benefit from the arrays that deliver up to 3478 lumens at 33 watts, 85°C.

The Oslon Black Flat LED from Osram Opto Semiconductors is now available in a two-chip version. Suitable for all headlight functions, the LED is an SMT component that can be directly attached to a PCB and processed with other components as part of the standard soldering process. The capability saves both cost and time, given the LED’s reduced complexity.

The LED achieves over 500 lumens at 1 ampere from a compact 3.1 mm x 3.75 mm x 0.5 mm (height) package. The slimmer LED is suitable for both low beams and high beams, fog lamps and daytime running lights with guides where optical incoupling is used.