A comparison between the BT.709- and BT.2020-compatible displays.
A comparison between the BT.709- and BT.2020-compatible displays.
[Click to enlarge image]
An image of various flowers
An image of various flowers
[Click to enlarge image]
The map of the colors of an image (xy chromaticity diagram). The distribution of the light-blue, green and red colors clearly does not fit in the color gamut of the BT.709 but almost fits in the color gamut of the BT.2020.
The map of the colors of an image (xy chromaticity diagram). The distribution of the light-blue, green and red colors clearly does not fit in the color gamut of the BT.709 but almost fits in the color gamut of the BT.2020.
[Click to enlarge image]

NHK Science & Technology Research Laboratories (STRL) will exhibit a 50-inch LCD display that has a very wide color gamut and uses a laser-based backlight at Open House 2015, which runs from May 28 to 31, 2015.

"It has the widest color gamut in the world at this point," STRL said.

STRL developed the display to realize the super-wide color gamut defined in the "ITU-R Recommendation BT.2020." The BT.2020 is an international standard for 4k and 8k displays, and NHK (Nippon Broadcasting System) was deeply involved in its formulation.

The color gamut defined in the BT.2020 is about 70% wider than that defined in the "ITU-R Recommendation BT.709," a standard for existing high-definition (HD) TVs, and even wider than those of the Adobe RGB and NTSC wide color gamut standards.

Therefore, it is not easy to make a display that supports the color gamut of the BT.2020. Even with OLED displays and LCD displays using quantum dots, the color gamut of the BT.2020 has not yet been realized.

This time, the color gamut of the BT.2020 has been almost realized by using laser diodes that emit red, green and blue lights for the backlight of the LCD display. The color gamut inclusion ratio of the display is 98%, STRL said.

According to STRL, when the wide color gamut display is compared with displays supporting the BT.709, there tend to be differences in the display of green, light-blue and greenish blue colors, STRL said. Those colors are important for displaying the colors of the sea. STRL showed the differences by using an image of the sea displayed on the BT.709- and BT.2020-compatible displays.