Are you curious about the terms AMOLED, Super AMOLED, IPS, infinity display, etc which you may have seen among the specifications of your mobile phones and Tablets? These are of course different versions of display technologies of our times. All the major tech giants like Apple, Samsung, One Plus use one among these technologies for building the displays of their Apple phones or Galaxy Notes. Each has its advantages and disadvantages. So which one is better? Is it the AMOLED favoured mostly by Samsung? Or is it the IPS LCD favoured by Apple for their iPhones? Let us take a detailed look at the features of AMOLED vs IPS display technologies.
There are mainly two types of displays used in smart devices these days,
- LCD:[Liquid Crystal Display] eg. IPS LCD
- LED :[Light Emitting Diode] eg: AMOLED
What is an AMOLED display?
AMOLED stands for Active-Matrix Organic Light-Emitting Diode is a type of display used mainly in mobile phones. You might have seen the AMOLED display mentioned in the specifications for smart devices especially mobile phones. They are also used in smartwatches, laptops and even televisions. Let’s see what the terms in AMOLED mean.
The Active Matrix technology came about as an improvement on the existing passive matrix technology that used passive components like wires which were arranged vertically and horizontally to control each pixel. The colour and brightness of the pixels and thereby the picture can be altered by varying the electrical charge at the given joint of vertical and horizontal wires.
The newer Active Matrix uses active electrical components like transistors and capacitors to carry out the same purpose. Instead of varying current at the intersection of wires to control the pixels, this latest technology uses a grid or matrix of thin-film transistors commonly referred to as TFTs and capacitors.
While varying current at the intersection was the trigger to change brightness and colour in the former technology, the latter modifies the charge of the capacitors to control the pixels. The colours are controlled by varying the charge of the corresponding capacitors emitting the primary colours.
The major difference between the two technologies apart from the components used is the fact that in a passive matrix, the entire row of wires needed to be charged to modify each pixel whereas now the pixels can be altered directly. The improvement in response time is the major advantage of switching to this new technology. Thus a display monitor using the active matrix technology has a clearer output for fast-moving images compared to one using the old passive matrix technology.
OLED (Organic Light Emitting Diode)
You might be familiar with the giant LED bulbs used in parties or even as indicators on televisions showing the on/off state. These same LED lights are used in AMOLEDs, but of course in the smallest size possible. The LEDs used are in the primary shades namely Red, Blue, and Green and are grouped in triangle-shaped pixelated forms.
The Organic Light Emitting Diode commonly referred to as OLED. It is pronounced as “oh-led”. OLED is a type of display in which each LED lights up one at a time. When you light them up together in different intensities, you will get more colours in the spectrum. So all LEDs switched on the same time gives you white colour and similarly switching off all the LEDs together gives black colour. An OLED display is comprised of a substrate, an anode, a conductive layer, an emissive layer, a cathode, and the cover. The substrate is either plastic or glass that supports the display panel. This technology display light using a process called electrophosphorescence.
When electrical current flows through the panel, electrons are removed from the panel. When an electric current flows from the cathode to anode, electrons move to the emissive layer and finally fills in the holes in the conductive layer producing light. The emissive layer and the conductive layer in the panel is filled with organic molecules. The colour of light produced by OLED depends on the organic molecules filled in the emissive layer of the panel and hence the name Organic LEDs.
Compared to the LCD and LED displays, the diodes in the OLED display produce light individually meaning they do not need backlight like its predecessors. OLEDs use lesser electricity and are thinner compared to LEDs. They are also bendable and may even be curved. However, they are much expensive than LED displays. Hence in the earlier days, it was majorly used for displays for smartphones and tablets.
AMOLED Display Technology
Now the technologies mentioned above combine to give the AMOLED displays. Here an OLED display is driven with an active matrix control scheme. The TFTs (thin-film transistors) turn on/off each pixel one at a time. The other scheme where the OLEDs are controlled by a passive matrix requires each grid ( rows and lines) to be controlled together. The advanced AMOLED displays allow for higher resolution display with a much bigger physical size.
AMOLEDs have deep black lights. The blacks are darker than LEDs and LCDs because parts of the screen can be switched off altogether. AMOLEDs are also thinner and lighter than LCDs. This feature especially stands out in a dark theatre room where OLED displays give a higher contrast ratio compared to LCDs making for an excellent visual experience. This feature of OLED which can work with no backlight makes it better than LCDs whether or not they have an LED backlight.
Phones with AMOLED display have been ruling the market since it was introduced over a decade ago in 2008. Advancements in technology have led to Super AMOLED displays that have integrated touch functions giving superior visual clarity and capable of changing according to the lighting in the room automatically meaning you get less strain on the eyes.
Advantages of AMOLEDs
- Since they use Active Matrix technology over the passive matrix version, AMOLEDs have a faster response time. They are up to a millisecond faster and extract less power of your mobile phone’s battery. Extended battery life means major advantages in the portability department. This adding to its high display features leads to them being extensively used. They are preferred over the other versions by major companies like Samsung. Speaking of power, the amount consumed by an OLED display varies according to the brightness and colour of the picture displayed.
- AMOLEDs have impressive contrast ratios. The contrast ratio is the ratio of the luminance of white colour to the black colour of a display unit. The high contrast of AMOLEDs is because when the LEDs are off, it gives complete black and since no backlight is used in LEDs, we get deep blacks.
Simply put, the black in LED is blacker than the black in LCD.
Disadvantages of AMOLEDs
- One of the disadvantages the AMOLED had over LCD was the blurriness caused in sunlight which is a result of its lowered peak-brightness values. This issue was corrected in the advanced Super AMOLEDs. In the Super AMOLEDs, size of gaps between the various layers of the screen namely the cathode layer, anode layer, organic active layer, TFT layer is made narrower than before.
- Another problem associated with the AMOLEDs is that the organic materials used in the emissive layer and the conductive layer suffer degradation. This happens comparatively in a short amount of time. As a result, various display problems arise including image persistence, burn-in, etc which are essentially screen burn type problems and colour shifts where some colours fade quicker than others. Burn-in is essentially the pixel quality becoming trash after a while because of the degradation of the organic molecules.
What is an IPS display?
Most flagship models of major companies like Samsung, Apple and One Plus use either super AMOLED or IPS panel premium LCDs. So what exactly is an IPS display? and how does it feature against like the likes of super AMOLEDs?
First, let us understand the basics of a standard LCD. Simply put, when you apply current to some crystals, they may or may not let through the light which comes from a backlight that covers the whole display. In addition to this, there are polarization and colour filters present in LCDs which finally gives the primary colours Red, Blue, and Green.
Before we get into detailed explanations, you have to keep in mind that for the final end-product that ends up on the market, the quality of the display does not solely depend on whether it is IPS or AMOLED. The companies usually put their tweaks on top of the existing technology before making them available in the market. AMOLEDs are a newer technology than IPS LCD and improve on it in some areas while still lagging in others.
The IPS LCD stands for In-Plane Switching Liquid Crystal Displays. It emerged on to the scene as an improvement on the existing and vulnerable Thin Film Transistor LCD technology commonly referred to as the TFT. Samsung was the leading manufacturers to employ Super AMOLEDs. The IPS display is mainly being used in Apple iPhones. Apple beginning with the iPhone X is switching to AMOLED displays with contrast ratios of 1000000 to 1
As said before, an IPS display is an improved version of the regular TFT LCDs. Here, the difference comes in the way the anode and the cathode are arranged. They are planted as strip electrodes on one of the two glass substrates. It can be seen in the IPS display schematic shown below.
The inhomogeneous electric field produced by these electrodes is used to switch the Liquid Crystal molecules. The molecules are found parallel to the glass substrate. The electric field forms parallel to the substrate surface and the LC molecules switch corresponding to the electric field. They become vertical to the substrate on the same plane. This 90-degree switching is referred to as the In-Plane Switching process.
The IPS display scores big time when it comes to offering better viewing angles compared to the other LCD technologies like Twisted Nematic LCD (TN) and Vertical Alignment LCD (VA). The images on the IPS display can be viewed without any colour degradation or blurriness at flimsy shallow angles compared to TN and VA displays. You can see the difference in the clarity of pictures shown on an IPS LCD and a TN LCD from the picture given below.
Features of IPS display
- The consistency of colours and clarity of pictures at wider viewing angles is the major advantage of an LCD. IPS displays have higher resolution. They also can display a wide range of colours. These features also make the IPS displays costlier than TN and VA LCDs. Normally IPS monitors allow up to 178 degrees of viewing angles. These displays almost guarantee absolute colour accuracy.
- For other LCD models, the colour and the brightness of an image vary when viewed from different angles. Comparing with them, IPS displays are more suited for someone working as a visual/graphic artist. As a regular television, all LCD models are mostly considered equally good. This is because the viewers would mostly be sitting right in front of the screen where these differences between the models do not matter.
- IPS displays are capable of displaying a wider spectrum of colours. Considering no monitors can display the entire colour spectrum visible to the human eye, IPS LCD panels are the closest things to a perfect display monitor far better than TN and VA LCDs
Disadvantages of IPS LCD
- The problem with LED is since when the display is black, the backlight is still on resulting in needless consumption of your precious battery life.
- Image retention is a problem often associated with LCDs. This happens because the crystal which gets into a particular position for the light to go through stays in that same spot without falling back into its original position. This leads to some parts of the image being left on the screen. This is, however, a temporary problem. The crystal will eventually twist back into the position when current is applied to it again. When it comes to colour accuracy, the previous generation of LCDs was no match for the AMOLED. They had the highest colour accuracy among mobile phones. But recent versions of the LCDs have fared much better versus their counterparts.
- Large-sized IPS monitors are not affordable for the average customer. They should be avoided since they offer nothing impressive over other LCDs considering the price range. However, if you are a visual artist or a photographer, IPS displays provide the best colour accuracy in the market. It would be more beneficial to you compared to an ordinary TN display unit.
AMOLEDs and IPS LCDs are two sides of the same coin in a sense. They both got their advantages and disadvantages. Their disadvantages are mostly overshadowed by the many tweaks installed by the parent companies to ensure customer satisfaction. From high power consumption to ugly blacks, the flaws are minimized in every newer version.
Apple beginning with the iPhone X is switching to AMOLED displays with contrast ratios of 1000000 to 1. So I would choose anything LED over LCD since LCD technology has probably peaked and hence the switch by Apple. Choosing one display technology over the other should purely be a matter of personal preference. Now that you understand the technology behind these displays, you can choose one yourself.