What is the difference between LED, Q-LED and OLED?


All forms of image or video reproduction require a source of light. This light is than managed and controlled in order to create the image/video. The light source technology used is what makes all the difference from one TV to the other.

LED & Q-LED – Transmissive technologies

Both LED and Q-LED televisions use Light Emitting diodes for backlight. Light Emitting Diodes are a very small extremely efficient light source. In front of the Light source, a diffuser and a number of filters manage the light coming from the LEDs to create the image.

Q-LED (Quantum Dots Light Emitting Diode) are LED backlit panels which deploy an extra filter using Quantum Dot Technology to better manage the picture quality than regular LED TVs. The Quantum Dots are microscopic molecules that, when hit by light, emit their own, different coloured light.
The very last “filter” used in both the above cases is the actual matrix of PIXELS, which will open or close to allow light through.
Both LED and QLED TVs are considered as “Transmissive” technologies, or they both rely on an LED backlight.

OLED TECHNOLOGY – Organic Light Emitting Technology - Emissive

OLED Technology is completely different to both LED and Q-LED. While LED and QLED are Transmissive, (require a backlight), OLED technology is Emissive. While all previous technologies manage an LED light source through filters, OLED panels are the light source themselves, therefore, no filters are required to control the light being emitted. If a dark scene is required, the Pixel is not closed to avoid light going through but the actual OLED pixel is turned off or dimmed as required. This major difference allows OLED technology not to suffer from any light leakage which is considered as normal in LED / QLED.

Which TV should I buy ?

When purchasing a TV, there are three main factors that influence your decision :

  1. PRICE
  2. Picture Quality
  3. Smart Features

The Price, in most cases, is the major deciding factor, however, that is a very subjective element. Picture quality and Smart Features are the other two major influencing elements in the buying decision process. The Picture quality is the result of not just the panel technology (emissive or transmissive) but a number of other factors influence the end result.

Other factors effecting Picture Quality

Following are the main factors that influence Picture Quality :

  • Resolution – Full HD (1920 X 1080P) – Ultra HD (4K) – (3840 X 2160P) OR now 8K
  • Picture processing – Proprietary technologies such as Philips’ p5 processor.
  • Colour & Contrast Management – HDR/HDR10+/Dolby Vision
  • Contrast Ratio – (very tricky since often no objective comparable measure is available
  • Refresh rate – (also very tricky – the numbers here should read 60Hz or 120Hz instead we find numbers running into thousands…. more about this in  seperate article)
  • Response time – This is not often advertised.. however, it does make a big difference during fast motion.

Every TV manufacturer has its own research team trying to get the best picture possible out of the technology used in every model. And the combination of back-lighting technology together with attention to each of the other parameters mentioned above results in a great TV.

Like all rival technologies, there are advantages and disadvantages that need to be weighed in order for us to make the right buying decision. The table below tries to simplify this :

Back Light Technology LED QLED OLED
Price €€ €€€
Colour Accuracy * ** ****
Contrast * ** ****
Black Levels * ** ****
Viewing Angle * * ****
Brightness *** **** **
Slim Design ** ** ****
Fast Response Time ** ** ****