Confused about all the different premium smartphone screens? Here's a quick explainer on the different display technologies.
Smartphones are ever-changing and evolving — between 108 MP cameras, 4K displays, 5G networks, and 5 nm processors, it's difficult to keep up with the blur of information hurtling around in the industry. One aspect evolving as fast as any other is display tech. Aside from a bump in screen resolution and size, the industry is now gravitating to a different type of display altogether — a technology that promises inky blacks, high contrast, low response times, and incredible brightness. OLED technology has been around since the early 2000s — first in simple, low-color, self-illuminating displays on early smartphones; and later in TVs — but now it is overtaking the high-end smartphone landscape in a big way. So what has changed since the days of the flip phone to thrust OLED technology into the limelight?
Advancements in OLED tech led to the rise of the AMOLED and P OLED designs that shape the modern smartphone as we know it.
OLED, or organic light-emitting diode, is a display technology that runs a current through organic diodes on a glass substrate to create an image. The light-emitting pixels of an OLED display emit blue and yellow light. The yellow and blue light combine to form white light, which then passes through red, green, and blue subpixels in order to produce a single pixel. Because each pixel handles its own light and color, OLED displays do not need a separate backlight.
OLED displays offer deep, even blacks. This is a direct result of how the technology works — when no color is being displayed, there is no light being emitted by that portion of the display. This gives manufacturers the ability to implement things like an always-on display without burning through battery life too quickly.
Another key advantage of OLED tech is high contrast ratios. Technically, OLED displays offer "infinite contrast," or 1,000,000:1 contrast ratios — this is because OLED displays reproduce black by turning off pixels entirely, and contrast is measured by comparing the brightest part of the screen to the darkest part of the screen. Improved contrast makes on-screen content seem more vivid, and makes bright highlights look more impressive.
OLED displays are capable of displaying more colors, with greater color accuracy than their LCD peers — this is great for photographers and videographers using their phones to preview, edit, and create content.
OLED displays improve on the response times of LCDs. While it is common for an LCD to have a response time of around 5 ms, OLED displays have near-instantaneous pixel response times. LCDs often have lower response times because, in order to change from one color to another, they must physically change the orientation of a liquid crystal - this takes time. An OLED display simply turns a subpixel on or off with an electrical charge, giving them a much faster pixel response time. Fast pixel response time means that making high-refresh displays is much easier with OLED displays than LCDs.
The omission of a separate backlight and the use of fewer components means OLED displays can be thinner than LCDs, making them more versatile in their applications.
OLED displays can usually get brighter than LCDs in small portions of the display. Screen brightness is often a thermal limitation and since an OLED display doesn't have to boost the brightness of a backlight that covers the entire display, peak brightness can be much higher than LCDs. High peak brightness is especially important for HDR content.
OLED displays can also be transparent, depending on the materials used. Transparent displays are useful for in-display fingerprint readers and under-display cameras, which allow manufacturers to design smartphones with fewer and smaller bezels, notches, and display cutouts. When notches and cutouts are necessary, OLED displays have more even brightness around those cutouts and notches, compared with LCDs where the backlight has to make it around the cutout and things get a little messy.
OLED displays often consume less energy, especially when displaying dark images or UI elements, thanks to the pixel-level regulation of brightness.
As with any new technology, OLED tech is not without its flaws. OLED displays are prone to degradation from age and UV exposure. OLED display degradation is a result of the organic nature of the molecules that make up the diodes. The organic nature of OLED displays also leads to a phenomenon called burn-in, where static UI elements like menus, navigation bars, and status bars — that are on-screen for long periods of time — will leave a permanent ghost image, even when they are not being displayed. Burn-in has been somewhat mitigated by pixel shifting and technological advancements in recent years, though.
OLED panels often have higher peak brightness in small areas of the screen, though sustained and full-screen brightness is often lower than what an LCD may achieve. High-end OLED displays can reach high sustained brightness - close to 2000 nits in some cases - but reaching those levels drives up the already-high cost of manufacturing.
OLED displays are thinner than LCDs, meaning components are closer together, thus they are more fragile and prone to damage in high-impact or high-stress situations. Engineers combat this by using technologies like Gorilla Glass and robust, metal frames. Mitigation strategies like reinforced glass and metal frames make using an OLED display even more expensive.
OLED displays use less power than equivalent LCDs in many situations — especially when displaying images at low brightness levels — but, at high brightness levels, and with large portions of bright colors, an OLED display will usually use more power than an equivalent LCD.
P OLED, or polymer organic light-emitting diode, is a twist on OLED technology wherein the glass substrate is replaced by a flexible polymer. P OLED displays share most of the benefits of regular OLED displays, but they offer advantages in terms of durability and versatility.
P OLED displays replace glass substrates with plastic ones, which makes them more shock-resistant. The use of plastic in place of glass also makes P OLED displays flexible, so they can be used in foldable and rollable devices. Another unique advantage is in the implementation - designers can reduce bezel size by folding the electronics underneath an edge of the display, instead of having it be on the same plane. P OLED displays are also significantly thinner than OLED displays with glass substrates.
Note the difference between P OLED and pOLED. pOLED is the trademark that LG Display uses to brand its plastic OLED displays. It produces these displays for a variety of applications and companies. Google used pOLED displays on the Pixel 2 XL, LG used them on the LG Velvet and several wearables, and Apple reportedly used LG pOLED displays on some Apple Watch models. LG's pOLED displays seem to suffer from an increased risk of burn-in, as users of the Google Pixel 2 XL complained of burn-in after only a few months of use.
If you're buying a phone with an OLED display, you're buying a phone with an AMOLED display — since, in order to get to the resolution and size of a phone, an OLED display needs to be AMOLED. AMOLED is an acronym for "Active Matrix OLED," and modern OLED displays found in consumer electronics use an active matrix as opposed to passive matrices found in older OLED displays.
Older OLED displays (also known as passive matrix OLED, or PMOLED displays) use a passive matrix to drive rows of pixels sequentially. PMOLED screens are very primitive (think monochrome, or two-color displays on old phones, calculators, or MP3 players), and inefficient. PMOLED displays require an increase in voltage for every additional line of pixels added, which causes rapid display degradation when getting into higher resolutions.
Active-matrix, thin-film transistor arrays used in modern AMOLED displays are far more energy-efficient than passive OLED panels because they do not require that voltage increase as the resolution increases. AMOLED displays made by Samsung - branded Super AMOLED - are some of the best mobile displays on the market. They are incredibly bright, with displays on the likes of the Galaxy S22 Ultra getting up to a claimed 1,750 nits peak brightness.
Samsung's AMOLED displays also make use of plastic substrates, so they benefit from the same advantages mentioned above when speaking of P OLED - increased durability and versatility. Samsung also includes the touch layer in the display itself instead of on a separate layer above the display.
Display type is only one part of the puzzle. What use is exotic technology if it doesn't make any difference to the end-user? Smartphone manufacturers use many approaches to improve their displays. Let's look at a few other things you should look for, apart from just the display type:
Resolution is the number of pixels a screen has. It is usually written as a ratio - pixels on the long side by pixels on the short side - for example 1920 x 1080. Most smartphone displays will have a resolution between 720p (1280 x 720) on the low-end and 4k (3480 x 2160) on some Sony models. While 4k is excessive - and rare for anything under 15 inches - 720p, 1080p, and 1440p are all common smartphone resolutions.
The ideal smartphone screen resolution depends on the screen size - a metric called pixels per inch (PPI) describes the number of pixels in a vertical or horizontal inch of the display. For a 6-inch display, you should aim for at least 1080p - or above 350 PPI - this will ensure that text is crisp.
Refresh rate is the number of times per second a display refreshes. Higher refresh rates mean motion and animations look smoother. Generally, 60 Hz is the lowest commonly-found refresh rate and is perfectly serviceable. Many modern flagship, and a few mid-range, phones offer 90, 120, 144, and even 240 Hz displays.
While a 90 or 120 Hz refresh rate will be noticeable in everyday use, anything above that should be reserved for gaming since it will not be a noticeable change. A higher refresh rate will impact battery performance, so it is important to find a balance. Options like variable and adaptive refresh rate technology enable high refresh rates without battery compromises.
Smartphones are often used outside in bright sunlight, so display brightness is a huge factor. Display brightness is measured in nits or cd/m². Peak brightness is the momentary maximum brightness of a small portion of a screen, while sustained brightness is a more realistic representation of the brightness of the whole display. You should aim for above 600 nits of sustained brightness, since anything below that may cause legibility issues in bright conditions. On the other hand, brightness is measured logarithmically, not linearly - meaning 1,200 nits is only twice as bright as 300 nits. This is important to remember since many manufacturers lean heavily on high brightness metrics as a marketing point.
Knowledge is power — this is as true about the technology you buy as it is about anything else. You should know at least a little about the technology behind the products you use, to know when or why you may want to buy one product over the other. Manufacturers love to sell the updated version of a product based on some new technology or spec bump when, in reality, you may never need that improved tech. Display specifications are no different — while it is true that OLED displays may be the best option for some people, they command a premium and a lot of people wouldn't even notice the difference.
Brightness, refresh rate, and resolution are all key factors, and performance as a whole should be the determining factor in selecting a display — not the shiny new technology involved. If you're looking for a phone with an OLED display and high refresh rate, check out the best Android phones you can buy.
My tech enthusiast journey started around 2012, with my first Motorola Android device. I love to tinker with both hardware and software to make tech work for me and help others do the same.