Gone are the days of televisions and computer screens that made your films look like they’d rather have been prints on a piece of paper, had less color and depth than shadows on a wall at noon and were rumored to make you go blind if you sat at them for too long (well… the jury is still out on that one).
What the liquid crystal displays (LCD) of today have now that makes them so appealing is something called the backlight.
Backlight is a form, a category, of how the image onscreen is illuminated, one that illuminates your screen from the sides and the back.
In fact, from the best 4K TV to the best gaming monitors out there, nearly everything today has a backlight, and there are as many backlight types as there are good analogies – that is to say, limited, but efficient in their scope.
What is a Backlight And What if I Don’t Want One?
Backlight is what makes LCD and LED televisions the hotcakes that they are – in fact, it can be said (and it is, by most) that LED televisions are supposedly just LCDs with LEDs used for the backlight.
A backlight creates a display similar to a CRT through either ambient light or a special source. These backlight types are determined by how the backlight is arranged, such as whether or not there are panels, diodes, lamps, or if a diffuser is being used.
In most cases, the backlight is the layer that is farthest to the back in an LCD and is the one most relevant to what reaches your eyes. A polarizing filter can be used, for example, for the light valves to block the light’s passage.
Keeping OLED displays out of the decision (since they consume less power than devices utilizing blacklight, thus have that comparative advantage), devices using blacklights are more affordable and sleeker, being more efficient, lighter, and less clunky-looking. They have longer lifespans compared to older models, and in fact, including OLED devices, too.
A Handy Primer On The Different Backlight Types
There are five types of backlight types – it’s a confusing sentence, but don’t worry, we just worded it poorly. The five types of backlights are:
- LEDs (light-emitting diodes)
- ELPs (electroluminescent panels)
- Hot CFLs (cathode fluorescent lamps)
- Cold CFLs (cathode fluorescent lamps)
- Incandescent light bulbs
Some points to note about these, before we go any further: there are different types of cold CFLs and LEDs, and none of them are compatible with each other. LCD can mean either CCFL or LED, with the LCD being the top part of the display with either CCFL or LED as the backlight for the LCD. Additionally, of these, electroluminescent panels are notable in their lighting the entire surface uniformly, whereas others need to use a diffuser.
The LED/LCD Confusion Explained
You might be wondering, at this point, what LCDs actually do. The difference is all but gone now, existing only in name, in fact: LCDs used to employ CCFLs, and LEDs used to be, well, LED-lit. This all changed as LEDs got more advanced and, as said before, all LCD screens now use arrays of LEDs.
How it used to be was that CCFLs, arranged neatly in series, illuminated the crystals used in LCDs with an even amount of intensity – the problem? Nearly uniform brightness levels meant no picture depth. There was also the problem of these LCDs being thicker than they are now since arrays of CCFLs are larger than LEDs.
LED-backlit LCD screens, however, have different zones that can utilize local dimming to create a rich palette of color and depth that is not only truer to life but also brings dynamic options that enable better contrast levels as the user prefers. Since it’s the LED light source itself that’s dimmed, the blacks are deeper and in contrast, the image is more vibrant, far more vivid in how it’s presented.
OLED vs. QLED
OLED screens and displays, amazingly, don’t require a separate light source or a backlight but have incredibly minuscule organic compounds that respond to electrical signals. Each of these pixel-sized “diodes” can be individually turned on or off, meaning that the contrast ratio is the deepest on the market, right down to every single pixel. They’re also incredibly thin, for obvious reasons.
On the other hand, the QLED technology is similar only in its name, and that’s a confusion that can be cleared up best by understanding that the name comes from Quantum Dot technology that these TVs employ. It’s still a form of backlight, but incredibly futuristic especially in terms of brightness (both in grayscale and color) and HDR, and until now, it’s only exclusively used in LEDs and LCDs from Samsung.