A BT.2020 wide color gamut is obtained using a laser backlight liquid crystal display (LCD). A conventional side-edge laser backlight requires a wide bezel area to achieve uniform brightness. We developed stacked double light guide plates, with each plate comprising light-mixing and light-emitting areas. The light-mixing area of each plate overlaps the light-emitting area of another light guide plate, thereby reducing the bezel width from 150 to 15 mm for a 17-inch LCD.
The International Telecommunication Union Radiocommunication Sector (ITU-R) Recommendation BT.2020 was standardized for ultra-high definition television (UHDTV). The BT.2020 specifications are 8K resolutions, a wide color gamut, and 120-Hz driving. The BT.2020 color gamut is defined from the three primary monochrome colors. Therefore, changing the light source of the backlight from conventional light-emitting diodes (LEDs) to lasers is necessary. We succeeded in prototyping a 17-inch 8K liquid crystal display (LCD) that satisfies the BT.2020 specifications. The pixel density of the 17-inch 8K display is 510 ppi, and the color gamut covers 97% of BT.2020. The liquid crystal response time is 5 ms, which is sufficient for the 120-Hz driving. To achieve the above-mentioned specifications, we developed the following technologies. To expand the color gamut, an RGB laser backlight was used. A backlight with conventional LEDs as light sources only covered 52% of BT.2020. To reduce response time, we applied a faster in-plane switching LCD (IPS-LCD) named short-range lurch control (SLC) IPS-LCD. We succeeded in realizing a blur-free display using the SLC IPS.