![]() ![]() Still, Brgoch and Hariyani chose them for their prototype to get the best color. One drawback is that violet LEDs cost more. Places such as museums and clothing stores install white lighting made using violet LEDs. That’s because these are designed to show an object’s true color better than the more common bluer LEDs used in most home lights. Common house lighting uses blue LEDs coated with phosphors whose colors add to the LED’s colors to make white light.Ī rarer type of LED has a violet bulb. The white light shining out of an LED comes from the bulb color plus the colors of the phosphors used to coat the LED. ![]() While these same primary colors of pigment in paint or crayons mix to make black, light works the opposite way. LEDs create white light by mixing red, green and blue hues. Says Brgoch, “We wanted to know: ‘Can we get to a high-quality light bulb with warmer and better quality light?’” However, this too will distort the hues in whatever you’re viewing. Plus, the LEDs in this and other smartphones still emit enough blue light to affect the body’s internal clock and melatonin production. People can block out some blue light by wearing yellow glasses near bedtime. But this makes images look more red than normal, so users give up color quality. For example, the iPhone’s “night” mode shifts its color palette. Software helps some devices emit less blue light. She’s part of a team that’s choosing to fix it.Ī new violet LED, shown here in a drawing, uses red, green and blue-emitting phosphors to combine the colors of the visible spectrum and create white light. But, Hariyani says, “you have to be okay with the negative side effects - or fix it.” They are energy efficient, long-lasting and cost little. Most modern screens and lighting systems use blue LEDs. Even though your body craves sleep, it’s still getting that signal for wakefulness. Explainer: What is a hormone?Īnd our bodies may well get confused if it’s late and our eyes remain bathed in blue light from devices or indoor lighting. Blue light suppresses the melatonin hormone. It helps bring on sleep - unless blue light tells your body otherwise. Melatonin is a hormone produced at night. Normally that body clock winds down as daylight fades. And they tell your internal body clock that it’s time to be awake. Those same blue wavelengths are found in sunlight. Here, warm means the light contains less of the short, blue wavelengths that can mess with sleep. ![]() The Houston team created a new phosphor to make their LED shine with a “warm” white light. When the chip is coated with powdered phosphors, the color of the light shining through the lens changes. Behind the scenes is an LED chip, which has small light-emitting diodes attached to a printed circuit board. ![]() Light shines through the lens of an LED, usually a plastic bulb. These substances glow when hit with light. He and fellow University of Houston chemist Shruti Hariyani have been studying the properties of phosphors. He also helped design the new lighting technology. He’s a chemist at the University of Houston, Texas. It might even find use in TV, laptop and smartphone screens, says Jakoah Brgoch. This new light-emitting diode, or LED, might someday deliver the glow in lamps and other types of home lighting, its developers say. But a new type of lighting appears to get around these sleep-challenging effects so you can nod off easily at bedtime. And when blue light enters the eyes, your brain gets the message that it needs to stay awake. Even “white” light contains these blue wavelengths. You may not realize it, but the blue light from device screens and even common lamps will confuse your brain’s internal 24-hour clock. Put away your phone, too, or you may have trouble falling asleep. ![]()
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