QD-OLED Explained: What you need to know about the next big innovation for TV and Monitor displays - XDA Developers

Taking CES 2022 by storm, the next big thing in the advancement of OLEDs is what Samsung Display calls QD-OLED, or Quantum Dot OLED.

The purpose of these quantum dots is to produce highly saturated subpixels without using an organic high-purity light source of the same color, which are often costly or inefficient.

These panels were all W-OLED displays that use an RGBW pixel structure, meaning that each pixel is made up of four different-colored subpixels: red, green, blue, and white.

However, at its core, each subpixel is actually a white subpixel (hence the term W-OLED), and colored subpixels are achieved with a color filter that blocks out parts of the white light spectrum to produce red, green, or blue.

Because light is being subtracted from the light source for the three colored subpixels, this pixel structure is not the most efficient, and it’s the reason why an extra white subpixel is needed.

Instead of starting with a broad white spectrum for each subpixel and stripping away parts of it with color filters, QD-OLED starts with a simple blue light source and converts it into high-purity red and green subpixels while leaving the blue subpixels untouched.

The green and red peaks are derived from passing high-energy blue light through a quantum dot layer, and each peak is associated with its own colored subpixel.

One of the disadvantages of current W-OLED TVs is that relying on the extra white subpixel for additional brightness lowers the maximum color saturation as the display nears its peak brightness; the color volume is further reduced since color filters lose effectiveness at high brightness.

In the visible light spectrum, blue light has the shortest wavelength among red, green, and blue; thus it has the highest normalized energy.

If we take a deeper look inside an existing W-OLED panel, we would find that the white subpixels are actually made up of multiple light sources.

Initially, these subpixels were made up of blue LEDs together with a yellow phosphor, but LG Display moved on to using a combination of red, green, and blue emitters to create the white subpixels.

With QD-OLED, all of the subpixels are backed by the same blue light source, so color shifting should be next to non-existent.

However, blue organic materials generally have shorter lifespans compared to red and green materials, so the subpixels in QD-OLED may actually dim faster than W-OLED over time✝?

In principle, it works similar to how W-OLED packs its white subpixels: with a combination of red, green, and blue emitters in varying numbers and sizes so that they decay more uniformly.

Without just re-iterating the marketing material that Samsung Display has released, we find that QD-OLED offers a clear advantage in light efficiency over W-OLED, and the standard pixel structure that it enables allows for higher color volume for HDR and for high-brightness users.

We may also see QD-OLED becoming cheaper than W-OLED in the future, as it relies on only blue organic material instead of the myriad that LG Display has to source for its W-OLED.

OLED is heavily limited by the effectiveness of the blue organic material, so synthesizing an alternative light source opens up the gates to a whole new generation of screens

This design is similar to QD-OLED, but instead of using organic blue materials, QNED uses Gallium Nitride Nanorod LEDs as the light source while still using quantum dots to mold it