LG Display Co Ltd exhibited an LCD panel whose color gamut was expanded by using quantum dots at SID 2010, the largest international conference on display technologies.
The color gamut of the panel was expanded by 30% by using quantum-dot LEDs for the backlight source.
A quantum dot is a semiconductor grain with a diameter of several nanometers to about 20nm. Because a band gap appears where a quantum dot exists, it can be used for luminescence materials, etc.
When a quantum-dot LED is used for a backlight source, it can expand the color gamut of the LCD panel. It is because the colorimetric purity of a quantum-dot LED is higher than that of a normal LED.
The screen's diagonal dimension is 3.2 inches. The pixel count, pixel pitch and luminance of the LCD panel are 480 x 800, 0.087mm and 450cd/m2, respectively.
In general, to expand the color gamut of an LCD panel with a normal pixel structure (RGB colors), its power consumption has to be compromised. It is because the light transmission rate of the color filter is lowered by heightening the color of the color filter to expand the color gamut. Therefore, it becomes necessary to increase the luminance of the backlight, resulting in an increase in power consumption.
On the other hand, when quantum-dot LEDs with a high colorimetric purity are used as a backlight source, it becomes possible to expand the color gamut without heightening the color of the color filter, which makes it necessary to increase the power consumption of the LCD panel (or lower the luminance of the panel).
With quantum-dot LEDs, the luminous wavelength can be controlled by changing their size. This time, LG Display used quantum-dot LEDs as a light source that has peak areas for three colors. Moreover, the company combined it with a yellow YAG phosphors.
LG Display did not reveal the materials for the quantum-dot LED or when it will start commercial production of the LCD panel.