Ever since flat screens reached the mass market in the late '90s and early '00s, there have been rival technologies. First it was plasma vs LCD, then LCD vs LED and now LED vs OLED vs QLED. Throughout each generation, consumers have had some tricky decisions to navigate. But we're here to help, this article will go over the differences between traditional LCD and LED displays as well as the newer OLED and QLED technologies.
LED vs LCD
So to start, let's get the basic terminology defined. LED stands for light emitting diode, they are very small, efficient light sources that are used in LED displays along with a host of other consumer and industrial applications. LCD stands for liquid crystal display, which are essentially composed of two pieces of polarizing filter with a layer of liquid crystal molecules between them. When current from a semiconductor is applied, the molecules either align themselves to let the light pass through or block it. When current is applied selectively to the display some of the molecules transmit light while others don't and an image is created. Alternatively, you can think of the molecules as pixels that are either light or dark. A pixel if you are wondering, is the smallest point that can be controlled in the display.
Turns Out an LED is Also an LCD
Now one curious thing about a regular LED display is that they actually employ the same LCD technology that was just described. However, they are called LED displays because the backlight, that is the source of the light behind the LCD pixels, is an LED array. This is because LEDs cannot be made small enough to be used as individual pixels, so LCD molecules must still be utilized. That may seem like a bit of a misnomer, but the distinction is between current LED sets and older LCD screens. The older type of LCD displays used cold cathode flourescent lamps (CCFLs) as their light source. So-called LED screens became preferable around 10 years ago because the LED light source is smaller, more efficient and can be locally dimmed, which allows the image to have a greater degree of contrast in different areas of the screen. These days, just about all LCD displays are the LED types. So while an LED display is definitely preferable to the old CCFL style LCD, it's mostly a moot point since the CCFL screens are now fairly uncommon.
OLED, the O is for Organic. No, Not Like the Fruit
Now that we've illuminated some of the background of LCD vs LED (see what we did there?), let's get into the latest different types of LED technology. First up is OLED, which stands for organic light emitting diode. There's some pretty technical information on how OLEDs work, but for the purposes of this article we are going to say that an OLED uses a film of organic material, that is carbon based, that emits light when a current is applied and thus creates the image. You can find far more detail on how OLED technology works here. The important thing is that since this film emits its own light, no backlight is needed for these displays, which means the overall thickness of the panel can be much smaller when using an OLED type. But that's just the beginnings of the advantages to an OLED display. Let's take a look at the benefits that an OLED offers over an LED set. If you'd like to check out a side by side comparison of OLED and LED displays, you can read one over at Digital Trends.
Because the pixels in an OLED emit their own light and aren't just passing light from another source, the pixels themselves can be shut completely off. By contrast, pun intended, in an LED backlit LCD, some light can still be passed by a pixel that is intended to be in the "off" position. The result is that OLEDs offer better black levels as well as a higher degree of contrast between lighter and darker areas of the image. In addition to enhanced black levels and contrast, because OLEDs can control individual pixels directly rather than the larger diodes of an LED which indirectly illuminate clusters of pixels, the pixels can turn on and off faster in an OLED. This is a spec known as response rate. Since the response rate is faster in OLEDs, it results in an image that has less blur when depicting motion and also reduces general artifacts. Since the light source for an LED screen is slightly behind the image, the best viewing location is directly in front of it. When moving off axis, color and brightness will decrease greatly. On the other hand, with OLED pixels producing light right at the front of the panel, the off axis performance of OLED sets is excellent, even at viewing angles as great as 84 degrees, which is probably more off axis than anyone would ever be while actually watching something. The smaller diodes of an OLED are also more efficient and use less power than standard LED sets.
While OLEDs surpass LED displays in many significant ways, there are a few areas where LEDs TVs still compete. When OLEDs first launched back in 2013, they couldn't quite match up to the brightness of a regular LED set. But that's changed as OLEDs have improved on this front in the last couple years. As of now, in a head to head between standard LEDs and OLEDs, the jury is still out, with some folks preferring LED and others giving the nod to OLED. This bleeds over, sorry we couldn't resist, into color levels since brightness is a big factor in how saturated the color of an image will appear. While both LED and OLED TVs when using HDR will provide amazing color gamut, especially in a dark room, if you are watching in a brighter environments, the colors may be more vivid with an LED set. There's also a new type of LED set on the market that surpasses OLEDs in both of these areas, but more on that in a minute. Finally, LED bests OLED in a couple of other ways, price and selection. In terms of OLEDs, the least expensive 2018, 55" model you can buy is the LG B8 OLED at $2100. Now if you go for one of the 2017 55" sets that are still hanging around, you can get one for around $1500. But obviously you can get LED sets of that size for far less money with many 4K options available in the $500 range. One other thing about OLED, as of now all the panels are manufactured by LG. Yes, Panasonic, Sony and Philips have OLED models, but the panels are all from the same source; LG. The only differences between these brands beside the look of the box are the computer processors, the OS for the Smart TV functions and the features. It's been rumored that Samsung will be getting into the OLED game as early as next year, but these reports have not been confirmed.
QLED, Let's Get "Quantum"!
Speaking of Samsung, the grandaddy of flat panel TVs has its own LED technology called QLED. What's QLED? So glad you asked, the Q in QLED stands for quantum dots, which sort of sounds like an '90s TV show about time travel and ice cream. In any event, the first thing to point out is that QLED TVs are a form of LED backlit LCDs, so with a QLED you'll lose the advantages of a display that directly emits light from the pixels that were outlined above. However, in a QLED there is an additional photoluminescent layer of "quantum dots" which are moleclues that when hit with the light from the LEDs emit light of a different color. The result is a brighter, more colorful image in comparison with both OLED and standard LED technology. You can read a bit more detail on the quantum dot technology at CNET. But keep in mind as we mentioned, you will still get better black levels, contrast and response rates from a OLED display. Getting back to those rumors, it seems that Samsung is trying to create a best of both worlds with a quantom dot film incorporated into a display that uses an OLED film instead of a backlight, already being heralded as QD-OLED. They are still testing the technology out, but it should be viable and hit the market, it's pretty likely that it will be a big time innovation that should achieve wide adoption. As for QLEDs, they are also spendy, but still a little less than OLEDs as you can get a 55" model for around $1300.
Just Tell Me Already, Which Should I Get?
If only it were that simple. But while we can't definitively say one display type is always going to be superior, here's a quick recap of the strong points of each:
LED
- Least expensive
- Widest variety of choices
- Brightness and color should rival OLED
- Good for brighter rooms
OLED
- Deepest black levels
- Best contrast ratio
- Best response rate
- Best off axis viewing
- Good for darker rooms
- More efficient, uses less power
QLED
- Best color intensity
- Brightest picture
- Prices are in between LED and OLED
So that covers it, depending on which of the above factors is most important to you, let that guide your decision as to which type of set to buy. Personally, we would lean toward an OLED as those inky blacks and contrast ratios are one of the most important things for something like our beloved Star Wars movies. Plus, the list of pros for OLED is definitely longer than the other two types. But there are really no wrong answers here, each technology looks amazing in its own right and is sure to wow you and your family when movie night comes around.