Researchers are developing new LED bulbs, which are expected to emit less blue light

Compared with other types of lighting, LED bulbs have considerable advantages. Because they are more efficient, they need less power to run. They don't give off unnecessary heat like old incandescent bulbs, and the best bulbs live longer than fluorescent ones. But LEDs are not without problems. People suspect that overexposure to the blue light produced by today's standard LED bulbs can lead to health problems such as fatigue, mood disorders and insomnia, which are lingering. In addition, higher prices encourage buyers to consider other options.

The University of Houston team, led by jakoah brgoch, an associate professor of chemistry at the school of natural sciences and mathematics and chief researcher at the Texas superconducting center, is developing an LED bulb that uses the safer violet part of the visible spectrum for most of its energy. Instead of just masking blue light, they are developing a unique class of luminescent materials called phosphors, which can absorb the monochromatic emission of violet LEDs and convert light to cover most of the visible spectrum.

"Instead of using traditional blue LED chips to operate the LEDs that our team is creating, we are using purple LED chips instead. "This basically shifted from blue to purple as the base light source, and then converted the purple LED light into the broad-spectrum white light we see," brgoch explained The ultimate goal is to make this new violet based bulb as energy-efficient as possible, but also very cheap, so that the new lighting technology can be sold to consumers“

Their results were recently published in ACS applied materials and interfaces, a well-known academic journal of the American Chemical Society.

But technically speaking, there is no pure white light. If you point a prism at the bulb, you can see that its light is divided into different wavelengths, showing a beautiful color band from purple to red; This is what scientists call the visible spectrum. The light looks white, because the human eye and brain work together to blend the human perception of these independent bands into white light, which may be illuminating the words you read. Different types of light bulbs emphasize different parts of the visible spectrum of light.

Engineers at lighting companies manipulate this balance to create a specific atmosphere. A little more red will produce warm, round white light, which is very suitable in the living room, while the cool blue will emit clear white light, which is more suitable for office lighting. But outside the lab, the blue trend of LEDs has been inevitable.

"Sometimes you recognize it - the cheapest LED bulbs, sometimes it looks like a nice warm white light. But even in the most expensive bulb, if it's based on a blue LED, there's still quite a bit of blue light going in, "the professor explained. Recently, scientists have been focusing on how the frequency of light affects health“ With the emergence of LED lighting, companies have begun to try to understand how human beings interact with light, and more importantly, how light interacts with human beings. When you are sitting in an office, the blue hue in the light is a good thing, because they help you keep your spirits up, but the same light may keep you awake at night when you need to rest, which is very bad, Essentially, it's about following the natural circadian rhythm without being disrupted“

Sleep studies have shown that excessive exposure to blue light at night alters hormones such as melatonin, sometimes leading to insomnia, sleep cycle disorders, and other problems. Excessive exposure to blue light is also suspected to be the cause of cataracts. Urban residents living in LED based street lights, traffic lights and commercial signs are also exposed to more LEDs than suburban residents.

"It's not that we should remove all the blue light from your bulb. You need some blue spectrum. This is not to eliminate blue, but to keep it at a reasonable level. That's what our work seeks, "said shutI hariyani, the author of the paper and graduate research assistant.