measure smartphone display screens brands

Want to know more about mobile phone screen size in-depth? The screen size of mobile cell phones is provided as a diagonal measurement of the phone’s screen. If the size of a mobile phone is represented as pixels, Further, the measurement of the phone screen size in pixels of the sides of the phone screen, the width & height of the mobile phone in pixels and is known as ‘Resolution’.

Typically, the diagram of a phone can represent the smartphone screen dimensions in centimeters and inches. The phone screen is generally shown as light blue color and the screen size is effectively the diagonal distance from the top/bottom corner to the opposite corner at the bottom/top of the screen.

You can distinguish the size of the smartphones and are probably published in inches, but in numerous countries that show the metric system, like Europe and India, mobile phone screen sizes are also stated in centimeters. To convert inches into Centimeters multiply the inch value using 2.54 (1 inch =2.54 cm or centimeters). To receive the screen size in inches from centimeters, try to divide by 2.54.

Smartphone screen image: Here, the screen size is measured at about 10.2 cm or 4 inches which can be measured from the bottom left corner to the top right corner.

As per the current era, we live with smartphones every time and every individual seconds. Result of this, our phones can be utilized for listening to music, snapping pictures, studying, working, or even paying. You can get them with you in all forms of your work like standing, walking, on the way to work, or anything regarding your daily routine. Everyone prefers to keep their phones in their hands. So, we need to ensure the screen size to hold and use your phone.

Before 2 years, the standard practice was under basic usage to make a call with a smartphone ranging the screen size of over 6 inches, a PHABLET among phones, and a tablet, but the Phablet is the previous one.

In recent years, smartphone displays have developed far more acronyms than ever before with each different one featuring a different kind of technology. AMOLED, LCD, LED, IPS, TFT, PLS, LTPS, LTPO...the list continues to grow.

As if the different available technologies weren"t enough, component and smartphone manufacturers adopt more and more glorified names like "Super Retina XDR" and "Dynamic AMOLED", which end up increasing the potential for confusion among consumers. So let"s take a look at some of these terms used in smartphone specification sheets and decipher them.

There are many display types used in smartphones: LCD, OLED, AMOLED, Super AMOLED, TFT, IPS and a few others that are less frequently found on smartphones nowadays, like TFT-LCD. One of the most frequently found on mid-to-high range phones now is IPS-LCD. But what do these all mean?

LCD means Liquid Crystal Display, and its name refers to the array of liquid crystals illuminated by a backlight, and their ubiquity and relatively low cost make them a popular choice for smartphones and many other devices.

LCDs also tend to perform quite well in direct sunlight, as the entire display is illuminated from behind, but does suffer from potentially less accurate colour representation than displays that don"t require a backlight.

Within smartphones, you have both TFT and IPS displays. TFT stands for Thin Film Transistor, an advanced version of LCD that uses an active matrix (like the AM in AMOLED). Active matrix means that each pixel is attached to a transistor and capacitor individually.

The main advantage of TFT is its relatively low production cost and increased contrast when compared to traditional LCDs. The disadvantage of TFT LCDs is higher energy demands than some other LCDs, less impressive viewing angles and colour reproduction. It"s for these reasons, and falling costs of alternative options, that TFTs are not commonly used in smartphones anymore.Affiliate offer

IPS technology (In-Plane Switching) solves the problem that the first generation of LCD displays experience, which adopts the TN (Twisted Nematic) technique: where colour distortion occurs when you view the display from the side - an effect that continues to crop up on cheaper smartphones and tablets.

The PLS (Plane to Line Switching) standard uses an acronym that is very similar to that of IPS, and is it any wonder that its basic operation is also similar in nature? The technology, developed by Samsung Display, has the same characteristics as IPS displays - good colour reproduction and viewing angles, but a lower contrast level compared to OLED and LCD/VA displays.

According to Samsung Display, PLS panels have a lower production cost, higher brightness rates, and even superior viewing angles when compared to their rival, LG Display"s IPS panels. Ultimately, whether a PLS or IPS panel is used, it boils down to the choice of the component supplier.

This is a very common question after "LED" TVs were launched, with the short answer simply being LCD. The technology used in a LED display is liquid crystal, the difference being LEDs generating the backlight.

Despite the improvement in terms of contrast (and potentially brightness) over traditional LCD/LED displays, LCD/mini-LEDs still divide the screen into brightness zones — over 2,500 in the case of the iPad and 2021 "QNED" TVs from LG — compared to dozens or hundreds of zones in previous-generation FALD (full-array local dimming) displays, on which the LEDs are behind the LCD panel instead of the edges.

However, for even greater contrast control, done individually at each point on the screen, it is necessary to go to panels equipped with microLED technologies – still cost-prohibitive in 2021 – or OLED, which until recently were manufactured on a large scale only in sizes for smartphones or televisions.Affiliate offer

AMOLED stands for Active Matrix Organic Light-Emitting Diode. While this may sound complicated it actually isn"t. We already encountered the active matrix in TFT LCD technology, and OLED is simply a term for another thin-film display technology.

OLED is an organic material that, as the name implies, emits light when a current is passed through it. As opposed to LCD panels, which are back-lit, OLED displays are "always off" unless the individual pixels are electrified.

This means that OLED displays have much purer blacks and consume less energy when black or darker colours are displayed on-screen. However, lighter-coloured themes on AMOLED screens use considerably more power than an LCD using the same theme. OLED screens are also more expensive to produce than LCDs.

Because the black pixels are "off" in an OLED display, the contrast ratios are also higher compared to LCD screens. AMOLED displays have a very fast refresh rate too, but on the downside are not quite as visible in direct sunlight as backlit LCDs. Screen burn-in and diode degradation (because they are organic) are other factors to consider.Affiliate offer

OLED stands for Organic Light Emitting Diode. An OLED display is comprised of thin sheets of electroluminescent material, the main benefit of which is they produce their own light, and so don"t require a backlight, cutting down on energy requirements. OLED displays are more commonly referred to as AMOLED displays when used on smartphones or TVs.

As we"ve already covered, the AM part of AMOLED stands for Active Matrix, which is different from a Passive Matrix OLED (P-OLED), though these are less common in smartphones.

Super AMOLED is the name given by Samsung to its displays that used to only be found in high-end models but have now trickled down to more modestly specced devices. Like IPS LCDs, Super AMOLED improves upon the basic AMOLED premise by integrating the touch response layer into the display itself, rather than as an extra layer on top.

As a result, Super AMOLED displays handle sunlight better than AMOLED displays and also require less power. As the name implies, Super AMOLED is simply a better version of AMOLED. It"s not all just marketing bluster either: Samsung"s displays are regularly reviewed as some of the best around.

The technology debuted with the obscure Royole FlexPai, equipped with an OLED panel supplied by China"s BOE, and was then used in the Huawei Mate X (pictured above) and the Motorola Razr (2019), where both also sport BOE"s panel - and the Galaxy Flip and Fold lines, using the component supplied by Samsung Display.Affiliate offer

Resolution describes the number of individual pixels (or points) displayed on the screen and is usually presented for phones by the number of horizontal pixels — vertical when referring to TVs and monitors. More pixels on the same display allow for more detailed images and clearer text.

To make it easier to compare different models, brands usually adopt the same naming scheme made popular by the TV market with terms like HD, FullHD and UltraHD. But with phones adopting a wide range of different screen proportions, just knowing that is not enough to know the total pixels displayed on the screen.Common phone resolutions

But resolution in itself is not a good measure for image clarity, for that we need to consider the display size, resulting in the pixel density by area measured by DPI/PPI (dots/points per inch).Affiliate offer

Speaking of pixel density, this was one of Apple"s highlights back in 2010 during the launch of the iPhone 4. The company christened the LCD screen (LED, TFT, and IPS) used in the smartphone as "Retina Display", thanks to the high resolution of the panel used (960 by 640 pixels back then) in its 3.5-inch display.

The name coined by Apple"s marketing department is applied to screens which, according to the company, the human eye is unable to discern the individual pixels from a normal viewing distance. In the case of iPhones, the term was applied to displays with a pixel density that is greater than 300 ppi (dots per inch).

With the iPhone 11 Pro, another term was introduced to the equation: "Super Retina XDR". Still using an OLED panel (that is supplied by Samsung Display or LG Display), the smartphone brings even higher specs in terms of contrast - with a 2,000,000:1 ratio and brightness level of 1,200 nits, which have been specially optimized for displaying content in HDR format.

As a kind of consolation prize for iPhone XR and iPhone 11 buyers, who continued relying on LCD panels, Apple classified the display used in the smartphones with a new term, "Liquid Retina". This was later applied also to the iPad Pro and iPad Air models, with the name defining screens that boast a high range and colour accuracy, at least based on the company"s standards.

Nit, or candela per square meter in the international system (cd/m²), is a unit of measurement of luminance, i.e. the intensity of light emitted. In the case of smartphone screens and monitors in general, such a value defines just how bright the display is - the higher the value, the more intense the light emitted by the screen.

The result is smoother animations on the phone, both during regular use and in games, compared to screens that have a 60 Hz refresh rate which remains the standard rate in the market when it comes to displays.

Originally touted to be a "gimmick" in 2017, with the launch of the Razer Phone, the feature gained more and more momentum in due time, even with a corresponding decrease in battery life. In order to make the most of this feature, manufacturers began to adopt screens with variable refresh rates, which can be adjusted according to the content displayed - which is 24 fps in most movies, 30 or 60 fps in home video recordings, and so forth.

The same unit of measurement is used for the sampling rate. Although similar, the value here represents the number of times per second the screen is able to register touches. The higher the sample rate, the faster the smartphone registers such touches, which results in a faster response time.

To further muddy the alphabet soup that we"ve come across, you will also run into other less common terms that are often highlighted in promotional materials for smartphones.

TFT(Thin Film Transistor) - a type of LCD display that adopts a thin semiconductor layer deposited on the panel, which allows for active control of the colour intensity in each pixel, featuring a similar concept as that of active-matrix (AM) used in AMOLED displays. It is used in TN, IPS/PLS, VA/PVA/MVA panels, etc.

LTPS(Low Temperature PolySilicon) - a variation of the TFT that offers higher resolutions and lower power consumption compared to traditional TFT screens, based on a-Si (amorphous silicon) technology.

IGZO(Indium Gallium Zinc Oxide) - a semiconductor material used in TFT films, which also allows higher resolutions and lower power consumption, and sees action in different types of LCD screens (TN, IPS, VA) and OLED displays

LTPO(Low Temperature Polycrystaline Oxide) - a technology developed by Apple that can be used in both OLED and LCD displays, as it combines LTPS and IGZO techniques. The result? Lower power consumption. It has been used in the Apple Watch 4 and the Galaxy S21 Ultra.

LTPO allows the display to adjust its refresh rate, adapting dynamically to the content shown. Scrolling pages can trigger the fastest mode for a fluid viewing, while displaying a static image allows the phone to use a lower refresh rate, saving the battery.

Among televisions, the long-standing featured technology has always been miniLED - which consists of increasing the number of lighting zones in the backlight while still using an LCD panel. There are whispers going around that smartphones and smartwatches will be looking at incorporating microLED technology in their devices soon, with it being radically different from LCD/LED displays as it sports similar image characteristics to that of OLEDs.

A microLED display has one light-emitting diode for each subpixel of the screen - usually a set of red, green, and blue diodes for each dot. Chances are it will use a kind of inorganic material such as gallium nitride (GaN).

By adopting a self-emitting light technology, microLED displays do not require the use of a backlight, with each pixel being "turned off" individually. The result is impressive: your eyes see the same level of contrast as OLED displays, without suffering from the risk of image retention or burn-in of organic diodes.

This is one of the reasons that explain the adoption of such technology to date remains rather limited in scope. You will see them mainly in large screens of 75 to 150 inches only, which enable 4K resolution (3,840 x 2,160 resolution, which is close to 8.3 million pixels or 24.8 million RGB subpixels). This is a huge number of pixels to look at!

Another thing to be wary of is the price - at 170 million Korean won (about US$150,330 after conversion), that is certainly a lot of money to cough up for a 110-inch display.

Each technology has its own advantages and disadvantages but in recent years, OLED screens have gained prominence, especially with the adoption of the component in high-end flagship smartphones. It gained an even greater degree of popularity after the launch of the iPhone X, which cemented the position of OLED panels in the premium segment.

As previously stated, OLED/AMOLED screens have the advantage of a varied contrast level, resulting from individual brightness control for the pixels. Another result of this is the more realistic reproduction of black, as well as low power consumption when the screen shows off dark images - which has also helped to popularize dark modes on smartphones.

In addition, the organic diodes that give OLED screens their name can lose their ability to change their properties over time, and this happens when the same image is displayed for a long period of time. This problem is known as "burn-in", tends to manifest itself when higher brightness settings are applied for long periods of time.

In the case of LCD displays, the main advantage lies in the low manufacturing cost, with dozens of players in the market offering competitive pricing and a high production volume. Some brands have taken advantage of this feature to prioritize certain features - such as a higher refresh rate - instead of adopting an OLED panel, such as the Xiaomi Mi 10T.

When you buy a device, you will often see both screen size and resolution listed in the specs. The screensize is the physical measurement diagonally of the screen in inches. This is not to be confused with the resolution, which is the number of pixels on the screen often displayed as a width by height (i.e. 1024×768). Because devices with the same screen size can have very different resolutions, developers use viewports when they’re creating mobile friendly pages. Viewports are scaled down versions of resolutions that allows sites to be viewed more consistently across different devices. Viewports are often more standardized and smaller than resolution sizes.

While desktop and laptop displays are in landscape orientation (wider than tall), many mobile devices can be rotated to show websites in both landscape and portrait (taller than wide) orientations. This means that designers and developers must design for these differences.

While desktop and laptop displays are in landscape orientation (wider than tall), many mobile devices can be rotated to show websites in both landscape and portrait (taller than wide) orientations. This means that designers and developers must design for these differences.

Group the styling into the most typical device sizes for phones, tablets, and desktops. In this case, anything larger than 7 inches is usually displayed at desktop resolution or-

When it is time to settle for an upgrade or a replacement of your existing phone, other than the price factor, there are many other attributes that go a long way in influencing your decision to buy a new smartphone.

One of the important considerations that will more often than not play a decisive role in your selection of a smartphone is the choice of an appropriate screen size that is conducive to your distinct usage patterns.

With modern smartphones bringing the world to your fingertips, it is not surprising that the importance of the phone’s screen size has increased manifold since the multipurpose smartphone of today is not only limited to its basic functionality of making and receiving calls and messaging but also acts as an entertainment device-cum-gaming console for its owners.

Choosing an ideal display size can be a tricky affair as the market is flooded with smartphones that boast screen sizes of various dimensions. Other than the screen size, you should also know how to check the specifications and select the best smartphone for yourself

In this article, we will review the advantages and disadvantages of few of the trending smartphone screen sizes of 5”, 5.5” and 6” or even more bigger in order to help you make an informed decision that takes into account your specific needs and your individual preferences too.

Well-suited for day-to-day basics use, a 5-inch display size is the new normal that befits you when you are desirous of a functional phone that flaunts a large display but is compact enough to fit into your hand easily.

Apart from enabling you with the flexibility and comfort to use your phone single-handedly, such a moderated screen size ensures that activities such as browsing the net, playing games, watching movies, reading e-books and responding to emails do not seem cumbersome anymore when performed on the spacious display.

Features, ergonomics and aesthetics are not compromised either with an optimally sized screen size that leaves adequate space to pack in more features into your smartphone.

Additionally, opting for a 5-inch screen will allow you to experiment with smartphones of diverse makes and models from industry players such as Apple, Samsung, Google, Huawei, Oppo, Xiaomi, etc.

While a 5-inch screen size is a safe bet for you when elements like your phone’s portability, usability and productivity score high on your wish list, yet, a 5 inches display would imply that you have to make do with a viewing experience that can be enhanced manifold with the larger display variants.

Unlike the 5.5 inches and 6 inches models, a 5-inch screen size may also be indicative of a lower pixel count – a vital aspect that warrants deliberation, especially when you need superior display resolution to enjoy animated wallpapers and backgrounds and high definition games and movies.

Moreover, the restricted screen space can hinder your creativity to some extent as creating presentations and compressing HD videos is much more seamless on a bigger screen as opposed to a 5-inch display.

Also deemed as a phablet for its innovative take on a smartphone and a tablet, a 5.5 inch screen size should be your ‘go-to’ option when both productivity and entertainment are non-negotiable for you.

Much sought after by the gaming enthusiasts who crave for an expansive display to manoeuvre through the treacherous turns like a pro, it is also a preferred choice for the movie buffs who swear by a big screen for a cinematic experience right in the comfort of their homes.

Apart from delighting you with a better read, seamless typing functionalities and the flexibility to multitask across multiple windows, a 5.5 inches display makes handling of a gamut of apps and editing of spreadsheets and documents surprisingly effortless and comfortable.

Thus, workaholics who are heavily reliant upon their smartphones for Office and other applications will find a 5.5 inches screen size more relevant to their needs as opposed to the smaller displays. Apple, Samsung, LG and Xiaomi Redmi are few of the well-known brands that manufacture smartphones with a 5.5” display.

A 5.5 inches screen size can impede your comfort quotient as it is may not be compact enough to fit into your hand or pocket easily. Since a larger display size means a bigger battery for your phone, hence, owning a 5.5-inch smartphone could imply that your phone will take more time to charge unlike those with smaller batteries.

A popular fad in the ever-evolving world of smartphones, a 6 inches display is perfect for users who seek a canvas-like display to relish the latest blockbusters and graphic intensive games without having to squint for an up close and personal view of the distant images and swift and complex video actions.

Owing to its high resolution and amplified pixel density, a 6+-inch display is a better deal when you desire matchless clarity and sharpness of pictures to magnify your multimedia experience. Surfing the net is also a sheer delight when you engage in your browsing activities on your smartphone’s broad 6 inches screen.

Bibliophiles will strike a chord with this screen size as they can satiate their love for books to the fullest in the form of e-book apps. Since a bigger screen has the capacity to display more content in one go, hence, it endows the users with a continuous and comfortable read and eliminates the need to scroll down the screen frequently.

Smartphones with a commodious 6-inch screen size are also apt for the creative souls who aspire for a bigger canvas to let loose their imagination. Apple, Samsung, Huawei, Oppo, Vivo, Sony and Xiaomi are few of the renowned manufacturers of smartphones with 6 inches screen sizes.

Portability is the main concern with phones that flaunt super-sized 6-inch screens. Large screen phones are also not very convenient during travelling. Moreover, if your 6+” display is damaged or broken, replacing it can burn a hole in your pockets faster than a small screen that will usually cost you less.

Also, those with petite hands or ones who have an eye for compact phones may find it awkward to use such large phones for making and receiving calls. Lastly, it goes without saying that one has to be prepared to shell out more if they want to splurge upon a smartphone that provides them with a generous 6” display that literally leaves nothing to the imagination anymore!

But now as the displays have become longer and narrower, even 6+ inch screens are more convenient than phones of earlier generations. (Earlier smartphone screens had ratios of 16:9, while now screens of 18:9, 18.5:9 and even 20:9 have made head ways making them more convenient to use)

At Prizm Institute, the students enrolling into mobile servicing course are taught about all major smartphone specifications to consider and check while buying them.

With technology rapidly changing and making way for cutting-edge innovations in the realm of mobile computing, there is nothing called a best fit anymore as mobile companies are constantly on the lookout to design and develop smartphone models that score over their predecessors in terms of their usability and with respect to their features, performance and functionality. It is up to you as a consumer to decipher your distinct usage pattern and zero-in upon a screen size that complements your lifestyle effortlessly.

The "p-display" nomenclature used in this article refers to the number of pixels displayed across the width of a given phone"s screen. Earlier phones with lower than 720p (lower than HD ready resolution) are not included in this listing. The lists below are dynamic lists and may be sorted into alphabetical order by clicking on the "sort icons" at the top of the first column.

Humongous smartphones. Phablets. Call them what you will, it"s evident that the trend of ultralarge phone displays over 5 inches is here to stay. Travel back in time with us, from some of the most recent to the first of their kind.

It"s been a long time since we"ve seen a smartphone screen size balloon to 6 inches, but the Motorola-made Google Nexus 6 has that dubious honor. More or less an inflated version of the likable Moto X (second generation), the Nexus 6 really is a darn big phone; one that"s stuffed with high-end features as well.

With the Note 4 under way, the arrival of the more expensive Samsung"s Galaxy Note Edge came as somewhat of a surprise. A curved portion of the display acts as a second screen for launching apps and viewing notifications, but it also turns into a menu strip when you open certain apps.

LG"s 5.5-inch G3 is a smartphone beast that finally shows what LG can do. It"s one of the first phones to have a 2,560x1,440-pixel resolution, plus a 13-megapixel camera and ultrafast quad-core processor.

As if taking a bow, the LG G Flex folds its 6-inch OLED display forward toward its toes. Strangely featuring Android 4.2, the G Flex has LTE, a 13-megapixel camera, and a 3,500mAh arched battery developed by LG Chem. No longer limited to South Korea alone, you can also buy the Flex stateside with AT&T, Sprint and T-Mobile.

The 6-inch Vivo Xplay 3S may never leave China, but it did earn bragging rights for being the first smartphone with a 2K resolution display (2,560x1,440 pixels). High-flying specs make it on par with the Huawei Ascend Mate 2 4G in the previous slide.

Start with a Samsung Galaxy Note 3 and bend it slightly from edge to edge. This, in a nutshell, is the Samsung Galaxy Round, the electronics giant"s twist on smartphone displays. Like the LG G Flex, the Round uses a flexible AMOLED display that Samsung helped pioneer. While sales appear to be limited to South Korea where the G Flex is not, the Round is the better phone of the two.

The less expensive, more feature-light Nokia Lumia 1320 Windows Phone is still a great value for those seeking a 6-inch smartphone at a portion of the price.

The third iteration of Samsung"s Note line, the Note 3 brings on the muscle with a 5.7-inch display and top-shelf hardware, including a 1080p HD screen resolution, a quad-core LTE processor, and the same 13-megapixel camera seen in the Galaxy S4 flagship.

Somehow, the Samsung Galaxy Mega"s rounded edges make its undeniably oversize dimensions easier to palm. Videos and images viewed on its 6.3-inch, 720p HD screen are notably noisier and fuzzier than watching the same videos on incredibly dense superphones with smaller screens (like the Galaxy S4 and HTC One), but the price -- about $150 on contract -- makes the phone a budget bargain. Read our full Samsung Galaxy Mega review to find out if this phablet"s right for you.

A relative phablet pipsqueak at 5.2 inches, the LG G2 is the phone-maker"s most ambitious model yet. And yes, with its screen size larger than 5 inches, it"s absolutely in phablet territory. Piling on a 1080p HD display, a 13-megapixel camera, and a powerful quad-core Snapdragon 800 processor, LG is revving its engine to compete against its most deadly rival, Samsung. Read our full LG G2 review.

An absolute pocket-buster, Sony"s Xperia Z Ultra comes in at 6.44 inches, the largest smartphone yet. Those 90-degree corners and a single stylish round power button on the right spine look fantastic. All those angles, however, make the Z Ultra a sharp, awkward handful. The smaller, 5-inch Xperia Z is much easier to handle. Check out the light, waterproof, and humongous Sony Xperia Z Ultra.

Dr. Vivian Wing-Wah Yam is a Hong Kong chemist and in 2001 made history by becoming the youngest member of the Chinese Academy of Sciences. Dr. Yam’s research focuses on organic light-emitting diodes (OLED), which has led to more efficient displays for devices such as mobile phones and laptop computers. She has won many accolades for her contributions to photochemistry and continues to work toward the mission of offering safer and more efficient ways to produce artificial light. In the Pixels, Pictures, and Phones snack, you can learn more about screen technology and human visual perception by investigating images on your digital screens up close.

All screens flicker to some degree — be they TV screens, car navigation displays, monitors, tablets, and yes, even smartphone displays. In this article, we will talk a little about what flicker is, what can cause it (on smartphones in particular), and how we at DXOMARK test for it, quantify it, and measure its impact on the end-user experience.

Flicker is a quick oscillation of light output between on and off; it is measured in hertz (Hz) to quantify the frequency at which the oscillation occurs. While we may not be consciously aware of the flicker phenomenon, it’s important to understand that our eyes still physically respond to it — that is, our irises expand and contract in response to these changes in brightness. This involuntary physiological response can certainly explain why we may have a headache and particularly why our eyes can feel tired after looking at a display for an extended period of time — they have been working hard! (This is especially true when looking at a display in dark ambient conditions, such as reading in bed with the lights turned off, for reasons we’ll touch on a bit more below.)

Given the ubiquity of smartphones, it is unfortunate that the flicker on their displays (especially OLED displays) is still an issue for many people. But wait! Why do they flicker? Well, let’s remember that smartphone display hardware is based on either LCD (liquid crystal display) or OLED (organic light-emitting diode) technology. LCDs don’t emit their own light; rather, they are back-illuminated by a strip of LEDs whose light intensity is quite powerful so as to compensate for the brightness drop due to the low transmission rate of the LCD panel (caused mainly by the RGB color filter). By contrast, in an OLED display, every pixel is itself an OLED that produces its own light.

Since both LCDs and OLED smartphone displays are composed of light-emitting diodes, let’s describe how these diodes are driven. Because of a diode’s intrinsic physical properties, it cannot be dimmed by changing the intensity of the current (mA) without impacting the color of the light. So how do phone manufacturers dim displays? They make use of a technique called pulse-width modulation (PWM), which means that they turn the diodes off and on at varying rates. Because we normally should not be able to see this switching between off and on (in other words, the flicker!), our brains are fooled into perceiving the screen as simply dimmer overall (a phenomenon known as the “brain averaging effect”). How dim depends on how long the diodes are off versus how long they are on: the longer they’re off, the dimmer the screen will appear.

So both LCDs and OLED displays power their light sources differently, but both technologies are subject to flicker effect; however, it is usually more noticeable on OLED displays than on LCDs. For one thing, OLED displays and LCDs show PWM at different frequency ranges — the PWM of OLED displays range from ~50 to ~500 Hz, whereas the PWM of LCDs starts at around 1000 Hz or higher. Second, as the human eye may experience flicker sensitivity up to about 250 Hz (at least for most people), it should come as no surprise that OLED displays are more likely to cause eyestrain than LCDs.

An on/off modulation pair is called a period, and the amount of time that the diode is switched on in a period is called a duty cycle. The chart below illustrates how different PWMs affect the perceived brightness of a display:

A significant disadvantage to using PWM technology can be that when a display adjusts to its minimum brightness in very dim or completely dark ambient light conditions, the duty cycle is very short and the interval when the diode is off is proportionately much longer (for example, minimum brightness may translate to a 10% duty cycle, meaning that the diode is off for 90% of the period). At lower PWM frequencies, flicker can become much more noticeable, which helps explain why reading text or watching videos in bed at night is more likely to cause headaches and eyestrain than when viewing screens in brighter conditions.

The video below was shot with a Phantom VEO-E 340L camera at 1500 fps (as were the other videos further below), slowed down to 4 fps to show display pulse-width modulation (PWM) — the white areas separated by black lines that extend across the screen when brightness diminishes at regular intervals. You can see the difference between the Samsung Galaxy S20 Ultra 5G on the left, which has a medium duty cycle (around 60%), and the Huawei P40 Pro and the Oppo Find X2 Pro, which have long duty cycles (roughly 90%; the black lines show that the OLEDs are turned off, albeit briefly):

So how does DXOMARK measure flicker? One major way is with a device called, appropriately enough, a flickermeter (specifically, a TRD-200 from Westar Display Technologies), whose sole purpose is to measure quick oscillations in brightness. Our engineers follow a strict protocol for measuring flicker on each smartphone display: all devices are individually tested using their default settings under the exact same dark (< 0.1 lux) ambient lighting conditions, and are placed at the same distance from the flickermeter. We chart the output on this graph (which we use to compare up to four phones in our display reviews; note that you can click on the name of a phone in the legend on the bottom of the graph to remove or redraw its results):

Yes, it’s a cool-looking graph, but what does it mean? How should we read this? Well, first of all, keep in mind that these results correlate with each device’s PWM — the on/off power cycle that helps control screen brightness. The horizontal X axis show the frequency of the oscillations over time measured with the flickermeter in hertz (Hz). The vertical Y axis shows the SPD(dB)— spectral power density in decibels, which is the amount of power associated with one frequency of the signal that the display generates.

Keep in mind that our engineers base their evaluations and the scores they assign to smartphone displays not only on the objective tests they perform with flickermeters and other instruments, but also on perceptual tests that they conduct after being specially trained to see flicker.

To further illustrate flicker, our engineers used a DSLR mounted on a translation rail and moved it quickly while it took a slow (1/10 second) shot of the three mounted smartphone displays shown below to imitate the effects of PWM. In the image of the Samsung Galaxy Note20 Ultra 5G on the left, you can see each individual white dot; on the Huawei P40 Pro in the middle, the individual dots are much closer together, but are still largely discernible; in the image of the OnePlus 8 Pro, however, the dots look more like an almost continuous line. Unsurprisingly, flicker is stronger on the devices where the white dots are further from one another — that is, devices with a lower PWM frequency.

Let’s wrap things up by first repeating that flicker on smartphones is caused by the use of pulse-width modulation that turns light-emitting diodes off and on to control screen brightness levels. As we normally perceive flicker via our peripheral vision rather than via our “attending vision” (that is, what we specifically focus our eyes on), the small size of a smartphone screen makes it less likely that we will see flicker on it (unless we hold the phone very close to our eyes) than we might when viewing content on a laptop screen or monitor. When we do see flicker, however, it’s the PWM that is the culprit; and while flicker can be reduced on a phone with a higher refresh rate, you may sometimes see flicker on it anyway if the phone’s PWM is slow (as we saw with the Samsung Galaxy Note20 Ultra 5G).

Finally, it’s also important to remember that some people are more sensitive to noticing flicker than others; in fact, even people who may not consciously perceive flicker may nonetheless be sensitive to it, winding up with headaches or eyestrain after overdoing their screen time. Such people could choose an OLED smartphone with an anti-flicker feature, or one with an LCD. As you can see in the table below, the last entry shows the data for the Xiaomi Mi 10T Pro; since it uses LCD technology, its PWM frequency is so high that it in essence eliminates the flicker issue.

This all said, you can rest assured that if our testers do discover a smartphone that has noticeable problems with flicker at its default settings, we will let you know about it as part of its Display review. (And by the way, we’ll also mention if a smartphone comes with a “flicker-free” feature or setting.)