OLED vs AMOLED: What’s the difference? And which one is better? | 91mobiles.com

OLED and AMOLED display technologies have taken a boom in the past decade or so. They are now widely used in smartphones, laptops, wearables, and other consumer electronic devices. OLEDs generally consume less power than LCDs, but the AMOLED display type consumes even less power. That’s why AMOLED panels are widely used in low-power devices such as smartphones. However, OLED technology comes in PMOLED, Super AMOLED, POLED, and other variants as well to suit a variety of user needs. In this article, we particularly take a look at how OLED and AMOLED display technology compares, how it works under the hood, and the benefits it brings to the table. We also briefly take a look at the other OLED display derivatives in this article. So, without further ado, let’s get started.

OLED vs AMOLED display

The critical component in any OLED display is an LED or the light-emitting diode. When an electric charge is applied to this LED it produces various colours. These LEDs are arranged in a pattern to produce red, green, and blue light or RGB. The subpixels — red, green, and blue LEDs together form a pixel. They turn on/off individually in a pattern with the help of integrated/external circuitry to produce a variety of colours. The ‘O‘ in the OLED represents organic materials used in the construction of LED.

AMOLED is not much different from the OLED panels. It uses the same base technologies as the OLEDs. However, as explained above, an OLED or organic light-emitting diode uses organic materials between the anode and cathode conductors of an LED. AMOLED, on the other hand, uses Active Matrix in the OLED display. 

OLED vs AMOLED technology

Unlike traditional LCD displays, OLEDs do not need a backlight, as each pixel can produce its own visible light. This means OLEDs have deep blacks and come with an ‘infinite contrast ratio’. The display’s contrast is measured as the difference between the darkest and brightest points. As each pixel in an OLED can completely turn off, the difference between the darkest and brightest points is essentially infinite since the display brightness level can go down to 0 nits when displaying a true black colour.

This is where the OLED’s ‘infinite contrast ratio’ claims come from the manufacturers. OLEDs also boast brighter whites, wider colour gamut, low latencies, extremely high refresh rates, and more. This makes them an excellent choice compared to LCDs for instance, if you want to achieve the best picture quality.

AMOLED displays, on the other hand, integrate a TFT array (thin film transistor) to control each pixel in the display grid. The TFT array itself has a storage capacitor that controls the charge of the pixel. This makes AMOLED panels energy efficient and perfect for use in low-power devices such as smartphones. Most AMOLED displays in the market are either produced by Samsung Display or LG Display. AMOLED displays are “thinner, lighter and more flexible than OLED displays”, according to Samsung. AMOLED screens also come with high resolutions and refresh rates that make them an excellent choice for portable electronics such as smartphones for smoother UI animations and crisp text rendering.

AMOLED display types

There are two types of AMOLED displays available in the market right now:

1. Super AMOLED

Super AMOLED is the marketing term used by Samsung to market its AMOLED displays. Super AMOLED displays come with an integrated touch-sensitive layer in the AMOLED panel itself. While the display technology itself is the same, now it doesn’t need a separate touch-sensitive layer on top of the AMOLED panel to control it. Samsung’s Dynamic AMOLED displays are also Super AMOLED panels but with added HDR10+ certification with greater brightness levels.

2. POLED

A POLED display uses a plastic substrate instead of the glass substrate used in AMOLED or PMOLED displays. POLED refers to polymer organic light-emitting diodes. The use of plastic substrate makes POLED displays flexible — the technology behind the bendable/curved and rollable display devices. The POLED displays are thinner and more durable (shock resistance) than the traditional OLED displays that use a glass substrate which is rigid. The Samsung Galaxy Z Flip series and the LG G Flex series used a POLED display. POLED displays should not be confused with LG’s pOLED displays, which also use plastic substrates in the AMOELD panel to make them flexible. One of the things about the AMOLED display is that plastic substrates can be used to make them flexible just like the POLEDs.

OLED and AMOLED advantages and disadvantages

Since OLED and AMOLED are basically the same, they share similar advantages and disadvantages. Here’s a quick look at them:

Having said that, AMOLED displays have an edge over OLED as they are more power-efficient and can easily be embedded into a display of any size.

Advantages

Deep blacks

OLED and AMOLED displays boast deep blacks and brighter whites and are the best display type to watch your favourite movies, especially in a dark room. This is because each pixel in an OLED/AMOLED display can be completely turned off — resulting in true natural blacks. Unlike LDCs where backlighting renders greyish blacks.

Infinite contrast ratio

As explained above, OLED or AMOLEDs have an infinite contrast ratio. The contrast ratio is the measurement of the difference between the darkest and brightest spots on a display. Since the individual pixels completely turn off, OLEDs tend to have an ‘infinite contrast ratio’. You can see manufacturers claiming an incredible contrast ratio of 1,00,000:1 in the OLED/ AMOLED displays, providing an immersive viewing experience.

Increased power efficiency

OLED, as well as AMOLED, displays typically consume less power than mainstream LCD (liquid crystal displays) panels as OLEDs can produce their own visible light. This is especially true for AMOLED-based display panels, as their individual pixels have a storage capacitor that retains the charge, giving AMOLED display panels the next level of power efficiency. This means higher resolution 4K displays can be integrated into battery-powered devices such as smartphones with higher pixel density (PPI) without consuming too much power.

Flexible displays

OLED and AMOLED can be built on top of a glass substrate as well as a plastic substrate. The latter particularly enables OLED panels to be flexible, even thinner, and shatter-resistance than the traditional OLED panels with glass-based substrates. This mystical technology today powers bendable devices such as Samsung Galaxy Z Flip, LG G Flex, Motorola Razr, and many more.

Extremely high refresh rates

While LCD panels can have high refresh rates, OLEDs tend to go even further and can even feature display refresh rates as high as 120Hz/144Hz/240Hz. This is because AMOLED and OLEDs typically have extremely low response times. This also means you no longer have to deal with stutters and lags while scrolling through system UI and apps. Smartphone makers nowadays also incorporate various techniques such as including variable refresh rates to reduce power consumption even further — making OLEDs a preferred display technology when it comes to achieving best of the both worlds.

Wider colour gamut and viewing angles

The best OLED and AMOLED panels have an expansive colour gamut. The extended colour gamut makes images look more surreal as they now include more colours. Additionally, OLED and AMOLED displays have wider viewing angles compared to any other display technology. This means images are colour accurate even when viewed from narrow angles.

Brighter displays and thinner electronics

OLED and AMOLED displays usually tend to have brighter image rendering capabilities. And there are OLED technologies which can be used to boost the overall brightness level even further. Furthermore, OLEDs/ AMOLEDs can produce their own light and don’t rely on an additional backlighting layer to light pixels. This lets manufacturers produce thinner electronics.

Disadvantages

OLED burn-in

OLED burn-in refers to the image retention issues resulting from displaying static images for an extended amount of time. This results in a permanent ghost image on the panel. And the worst part is, the ghost image is still visible even when you turn off the screen. But modern technology such as OLED ‘pixel shifting‘ mitigates this issue to an extent by shifting static pixels periodically.

Perceived low resolution

As we explained, in an OLED display LEDs are arranged in a pattern to help produce images. Manufacturers have now settled on the RGB stripe (red, green, blue) as the standard for displays. Subpixels (red, green, and blue) are arranged in various RGB stripes — such as RGB, RGBG, RGBW, WRGB, Pentile, and more — to achieve various resolution and brightness goals and to even combat long-standing issues like OLED burn-in.

For instance, a full RGB pixel layout, where each pixel has all the RGB subpixels, has a high resolution compared to, say, a Pentile display using an RGBG subpixel layout. The RGBG layout, for instance, is used to combat the OLED burn-in/image retention issue by adding more green pixels, but in doing so, the perceived resolution of the display takes a hit. Subpixels are shared between individual pixels in a Pentile pixel layout (instead of each individual pixel getting all the RGB subpixels) to produce colour, resulting in pixelated edges while reading text at higher brightness levels. But with increasing screen resolution and PPI (pixel per inch) density in smartphones, manufacturers have resolved these issues to some extent.

Most OLED displays used in today’s smartphones are Pentile, according to The Verge, since they are affordable to manufacture and also last longer. Similarly, RGBW and WRGB subpixel layouts are used to enhance the overall brightness levels of the OLED displays.

Degrades over time

The organic materials used in manufacturing OLED displays also tend to degrade over the course of time, resulting in reduced display lifespan compared to LCD panels.

FAQs

Why are AMOLED displays not used on electronics such as TV and other big-screen devices?

With so widespread usage of AMOLED displays in electronics, it would seem unusual that they are not commonly used on big-screen devices such as TVs. The reason for this is AMOLEDs use low energy compared to pure OLED displays. Moreover, AMOLED display technology was invented to make electronics use less power in mobile devices such as smartphones, which are dependent on the limited battery capacity for power. Since devices such as TVs are usually directly connected to a power source, there is not much of a need to make use of AMOLED screens. That is why AMOLED displays are not commonly used on big-screen devices which are continuously connected to a power outlet.

What’s a PMOLED display?

PMOLED displays are another type of OLED display technology that is used in electronic devices. The ‘PM‘ part refers to the Passive matrix used in the OLED panel. PMOLED displays are usually suited for devices which have 2 to 3 inches screen size due to the way the technology works. PMOLED displays have rows and columns of anode and cathode conductors and the intersection of this forms a pixel in the display.

The external circuitry applies high voltage current to individual rows or columns in the grid sequentially which determines which pixels get turned on/off. The lack of a storage capacitor means that most of the pixels in the row or column are off, a high-voltage current is required to light up the pixels. The more rows and columns of pixels a PMOLED panel has, the more the current requirement.

This makes PMOLED technology not suited for high-resolution, large-screen devices, which are dependent on batteries for power. (Hence the usage of AMOLED displays in mobile devices which are dependent on the battery.) But it is worth noting that the current requirement of a PMOLED display is still lower than most competing LCDs in the market, particularly for lower screen size devices like wearables.