Quantum dot (QD)

Quantum dot is a relatively new display technology for television screens. QD are microscopic particles that emit light when electricity is applied, or when light is shone on them. The light’s color is very stable and relates to the QD’s size. Of late, they have been applied to screen technology in two ways.

One is to use them as a backlight for LCD screens. Currently LED screens use LEDs as the backlight, and an LCD filter to control the brightness of each screen ‘dot’ (not quantum!). QD backlight uses just a blue LED light which is converted by QDs to reasonably pure red and green – very close to the required red, blue and green – so far less light is absorbed in the RGB filters behind the LCD screen, so providing more useful light (brighter pictures) and more accurate colors, and it does not drift.

The other type of QD screen uses QD-based LEDs to directly emit the screen light – as OLEDs screens do now. However OLED screens remain at high prices and there is some fear of quality degradation over time. QD-LED color can be accurately tuned in manufacture and is has a narrow spectrum. It does not drift and is not known to degrade. Amazon’s Kindle Fire HDX tablet uses QD technology, as did Sony in 2013 with its Triluminous screens.