Seoul Semiconductor has introduced SunLike Series LEDs. The SunLike Series combines the company’s patented LED chip technology with Toshiba Materials’ TRI-R phosphor technology. Seoul optimized the SunLike Series LEDs for circadian rhythms. The company contends that the SunLike Series LED technology closely matches the spectrum of natural sunlight, and according to Seoul, the technology maximizes the benefits of natural light and minimizes the deficiencies of artificial light sources.
Mr. Kumpei Kobayashi, CEO of Toshiba Materials said, “We are pleased to be partnered with a global LED leader like Seoul Semiconductor to introduce the SunLike Series natural spectrum LEDs, which represent an advanced technology that creates a more intimate and nature-based lighting environment.”
“Much like our package-less WICOP Series LEDs revolutionized the LED packaging process, our SunLike Series LEDs represents a revolution in creating natural spectrum LED lighting.” said Mr. Chung Hoon Lee, CEO of Seoul Semiconductor. “The SunLike Series LEDs will be applied in the lighting sector, contributing to a better and healthier life for humans. They will also be used in horticultural applications to create an ideal environment to help plants grow, which is safer than using genetic modification,” he added.
He also said, “We are delighted to partner with Toshiba Materials to provide our customers a light source that delivers the natural spectrum of sunlight – from the brightness of morning sunshine, to the energy of daylight, to the warmth of an evening sunset. We believe that the SunLike Series LEDs will improve the quality of human life by advancing a new era of human-centric lighting technology.”
The company points out that Harvard and other universities have conducted recent studies which suggest that blue LED chips that are converted to white emitters stimulate the human eye resulting in increased alertness and elevated mood when viewed during daytime hours. However, when viewed for prolonged periods during night-time hours this blue light interfers with natural human biorhythms.
A purple LED in conjunction with Toshiba’s TRI-R phosphor compound minimize the blue light “spike” that is representative of conventional LED light sources.
SunLike’s Color Reproduction
Seoul Semiconductor gave a complex explanation of how its new series of LEDs enable very accurate color reproduction. The company points to research published in Nature that found that human retinal cells that respond to color-related light input are comprised of red, blue, and green cones. However, the percentage of blue receptors is just 5.7% (Roorda, 1999).
The amount of blue light that our eyes can accept is limited, and blue light above the limit entering the eye is scattered. When this blue light scattering phenomenon occurs, the resulting light is diffused making the texture and color of objects distorted. Also, exposure to excess blue light can over-stimulate these retinal cells, and may cause eyestrain and loss of concentration.
However, Seoul says that since SunLike Series LEDs emit light in the spectrum closest to the sunlight, they can more accurately represent an object’s color and texture in natural light without the negative consequences of excessive blue light on the eye such as a disruption of human biorhythms.
Several products which incorporate Toshiba’s TRI-R technology have already been applied to lighting for Milan Fashion Week and illuminating fine paintings in museum settings.
The company targets the SunLike Series of LEDs for use in lighting for commercial facilities that require the exact color rendering as seen under sunlight. Such applications include exhibition facilities such as museums and exhibition halls, department stores, fine jewelers, horticulture facilities for growing plants indoors, and dressing rooms or bathrooms.
Roorda A. & D. R. Williams. “The arrangement of the three cone classes in the living human eye”, Nature 397, 520-522 (11 February 1999). doi:10.1038/17383.