As a kind of color light, blue light is ubiquitous in various lamps. However, most of the LED lamps on the market currently emit blue light through the chip to excite yellow phosphors to reconcile the white light. Therefore, the blue light problem of the LED light source between 400nm and 500nm is particularly prominent.
Previous studies have confirmed that blue light with a wavelength of 450 to 500 nm can inhibit the production of melatonin, thereby affecting the quality of our night sleep. Now, researchers have developed an LED prototype. The LED reduces the blue component (instead of the mask), reduces the blue component, and at the same time makes the color look like it is in natural sunlight. The research was published in the journal ACS Applied Materials & Interfaces.
The prototype device can produce warm white light without the blue hue that can cause health problems
As a proof of concept, the researchers identified and synthesized a new type of luminescent crystal phosphor containing europium ((Na1.92Eu0.04)MgPO4F). In the thermal stability test, the emission color of the phosphor remains consistent between room temperature and the higher operating temperature (149.4°C) of commercial LED lighting. In the long-term humidity test, the color of the compound or the intensity of the light produced did not change.
In order to understand how this material works in the bulb, the researchers created a prototype device: a purple LED bulb covered with a silicone cap containing their blue luminescent compound mixed with red luminescent and green luminescent phosphors. It produces the required bright warm white light while minimizing the intensity of blue wavelengths, which is different from commercial LED bulbs.
The researchers said that the optical properties of the prototype can almost show the color of objects like natural sunlight, which satisfies the needs of indoor lighting, although they added that more work needs to be done before it is ready for daily use.
