OLED vs LCD: What’s the Difference?



By: Vinh Lam

The iPhone X, a flagship phone with a OLED display. (Wikimedia Commons)

Most people have heard of OLED. After all, most flagship phones, such as the iPhone XS and the Samsung Galaxy S10, are advertised as featuring an OLED screen. Also, many high-end TVs are advertised as OLED. What exactly is OLED, and how does it differ from LCD screens?

What is OLED?

OLED, Organic Light Emitting Diode, is a type of LED that emits its own light in response to electric current. LCDs, on the other hand, do not emit their own light and are lit by a backlight to produce a color or monochrome image. Since OLED displays do not require a backlight to produce light, they can be far thinner and they tend to be more flexible than LCD screens. Since they emit their own light, they can display true blacks because the pixels can just turn off when black is displayed. LCDs, though, use a backlight so all pixels are slightly lit at all times. OLED screens usually have higher contrast ratio than LCDs.

If OLED has all of these advantages over LCD, then why isn’t everyone using it in their products?

There are many reasons LCD is used over OLED. One of the biggest reasons is the cost. Currently, OLED displays cost more to make than an LCD display because of how difficult it currently is to make the OLED substrate. It also has many disadvantages against LCD displays. OLED screens, like their predecessor Plasma displays, are also susceptible to burn-in if a static image is displayed on it for an extended period of time, while LCDs are mostly unaffected by it. While OLED displays use around 40% of the power of LCD displays displaying a mostly black image, OLED screens can use up to three times as much power as LCD screens when they display white. OLEDs have a far shorter lifespan than their LCD screen counterparts and a study in 2008 found that the lifespan of OLED screens was at around 14,000 hours to half maximum brightness as opposed to 25,000-40,000 hours for LCDs. OLED displays can’t the whole screen as bright as LCD displays can but they can get brighter than LCDs in certain portions of the screen.

An example of screen burn-in (Google Images)

So if OLED has so many disadvantages, why are people even using it?

As stated above, OLED displays emit their own light so they can display much deeper blacks and have higher contrasts than their LCD counterparts. Some OLED displays also get much brighter than LCD displays in certain spots on the screen and since they can completely turn off certain pixels to display true black, they tend to have high dynamic ranges which are also known as HDR. OLED displays tend to be more flexible than LCD displays because they don’t require the fragile backlight that LCDs need. For example, Apple folded the iPhone X’s screen under the bottom of the display to eliminate the bottom screen bezel that most phones still have. They have higher response times and refresh rates than their LCD counterparts. LCDs can currently have refresh rates of up to 240Hz and response times as short as 1-millisecond. OLED can be up to 1,000 times faster than LCDs, which means OLED displays could be capable of refresh rates as high as 100,000Hz and response times as short as a thousandth of a millisecond.

A flexible OLED display prototype from Sony (Flickr)

Ok, should everyone be using OLED then?

No, not everyone should be using OLED displays. People on a budget can get away with LCD displays and while those displays won’t look fantastic, they won’t look terrible either. For people who want a monitor for their computer, only LCD monitors are currently available and very few laptops actually have an OLED display. The reason why is that when static images are displayed on an OLED display, the OLED display tends to get burn-in, where a ghost-like image gets permanently stuck on the display. On computers, many things are static, such as the menu bar and app icons, which can cause burn-in on OLED displays. Also, with microLED on the way, people should not invest a lot in OLED because microLED is supposed to have most of OLED’s advantages while having very few of its drawbacks.

An Alienware Laptop, one of the few laptops that offer an OLED display option (Flickr)

Ok then, how is OLED related to engineering?

Quite a bit of engineering went into developing pixels that would emit their own light when an electric current passes through it, instead of using a backlight to turn pixels off completely when black is displayed. For the display makers, they had to engineer the device that the OLED display was going into so that the OLED display would not be exposed. This is because OLED is incredibly sensitive to water, and contact with water could instantly break it. They also had to engineer it so that it could be printed on different substrates.

Some more information about OLED and the different screen types:

Some videos on OLED: