National Institute for Materials Science and Technology (NIMS) and Sharp’s research team have a great success on the 23rd February 2017. They are successful in making a wide color gamut white light emitting diode (LED) suitable for 8K television.
It achieves 90% of the target color gamut of 8K broadcasting. Research representatives says: “It is a color gamut that can fully reproduce the cleanliness of the color for 8K broadcasting and it is a color gamut that can reproduce the color cleanness of 8K broadcasting “
The color reproduction range (white triangle) of the display uses this new development product (left). And the conventional product (right) with white LED backlight are obvious in picture above.
The research team consists of Naoto Furo Hirosaki of NIMS Functional Materials Research Center, Masaaki Izumi of Sharp R & D Headquarters, and Kenichi Yoshimura Researcher. By improving the coloring of the green phosphor which constitutes the LED, the vividness of the three primary colors of red, green and blue light is improved.
According to the BT.2020 standard that is for the spread of 8K television in 2020. It is wider color gamut than the conventional NTSC standard by 134% (on the CIE 1976 coordinate) in the color space area ratio. To realize this, a light source with good coloring effect is required. And it was not possible to cope with the current backlight technology.
In order to improve color reproducibility. It is necessary to increase the color purity of red, green and blue that are in the backlight. But at present it is larger than the red / blue component. Because the coloring of the green component is poor, the new color gamut improves by green phosphor.
8K Television Backlight Using Al2O3–γAlON (alumina–γ–aluminium oxynitride)
For the LED backlight prototyped this time. They used the γAlON (gammaaron), Al2O3–γAlON (alumina–γ–aluminium oxynitride) green phosphor developed by NIMS. The emission wavelength is 525 nm. Which is green with high color purity.
And the full width available at half maximum of the spectrum is 40 nm. As a result, pure green coloring is possible. And it is said that this technology is able to achieve 90% of the color reproduction range of the BT.2020 standard.
As a method of expanding the color gamut, “quantum dot” technology using cadmium has a practical application in some televisions. But in the new LED, the color gamut is changed without using harmful elements. It is advantageous that it can have expansions, because it can replace only the white LED parts of the current backlight. Meanwhile it is also superior in terms of cost.
8K Television In 2018
So in the future, after improving the brightness by improving material properties and reducing the cost. Incorporate it in the liquid crystal television and adjust the color reproducibility. For the start of 8K practical broadcasting in 2018. Many companiesaim to commercialize white LED suitable for backlight of 8K television.