Best phone screen: display tech explained
13th Aug 2012 | 09:51
Which mobile phone screen type is best?
Mobile phones have progressed dramatically since the days their displays needed only to show you the number of the person calling. Once we added text messaging and even email, we need a bit more space to see what we'd written.
We added colour to give them a bit more interest. When we started adding cameras to the phones, we wanted the screens to be sharper, so we could see the terrible, pixelated VGA photos we'd taken.
Once the ability to store video arrived, we needed them to be smooth, with good refresh rates.
In the era of touchscreen smartphones, we expect them to be as good as computer screens, offering crisp text, vibrant images, blur-free video and enough brightness to see outdoors, all under a responsive touch layer.
Predictably, several different options have arisen, especially when it comes to high-end smartphones. As a result, it can be hard to know exactly what manufacturers (and, indeed, technology sites) are talking about when they boast about Super AMOLED screens or Retina displays.
So what's the best phone screen to go for? We've rounded up all the important information about different mobile screen types below, so you'll know what to look out for on your next phone.
By far the most common kind of screen used on mobile phones is TFT-LCD (often just referred to as LCD, since TFT-based LCD screens are the only type used in practice). It ranges from the budget smartphones like the HTC Desire C to high-end tablets, like the Google Nexus 7.
TFT-LCD stands for thin-film transistor liquid crystal display and there are many different ways of manufacturing LCD screens, so knowing that a phone is LCD doesn't tell you much about its quality.
In practice, cheap phone screens will often display dull colours, and have narrow viewing angles, which means that if you look at them from off-centre, it becomes hard to see what's on-screen.
High quality LCD screens will have bright, accurate colours and with visibility from just about any angle.
All LCD screens need to have a light behind them, which shines through the pixels to make them visible. As a result, they don't offer quite the thinness of AMOLED technology.
Active-matrix organic light-emitting diode, or AMOLED for short, is a screen technology based on organic compounds that offers high image quality in exchange for potentially very low power usage.
Unlike LCD screens, AMOLED displays don't need a backlight - each pixel produces its own light - so phones using them can potentially be thinner.
It also means that a mostly black screen will use very little electricity, and true blacks when watching videos, rather than the dark grey some LCD screens produce.
However, AMOLED screens have proved costly and difficult to produce in the same numbers as LCD, a fact that led to the HTC Desire having its AMOLED screen replaced with Super-LCD halfway through its manufacturing life.
AMOLED uses a different subpixel arrangement to LCD, which can result in images that don't appear quite as sharp.
High-end LCD screens are also able to produce a wider colour range than AMOLED screens, though this would make little difference to most casual users.
This is a derived form of AMOLED screen that actually includes the capacitive touchscreen technology in the manufacturing process, meaning that it doesn't have to be overlaid later. It offers other advantages over earlier AMOLED screens, including increased brightness and lower power usage.
Super AMOLED Plus
A new technology first used by the Samsung Galaxy S2. The significant change is in the subpixel construction, switching to something much closer to that used by LCD, which meant sharper, clearer images.
Super AMOLED HD
A term coined by Samsung, Super AMOLED HD is simply a high-definition (720 x 1280 or higher) Super AMOLED display.
In an odd move Samsung ditched the subpixel construction from Super AMOLED Plus and returned instead to a standard Super AMOLED subpixel arrangement for this display, claiming that it was more durable.
Super AMOLED Plus HD
Putting right the 'one step forward, one step back' approach to a display used for Super AMOLED HD, Super AMOLED Plus HD is a high-definition Super AMOLED Plus display.
It's not a display type that's currently in use, but Samsung is rumoured to be working on it.
A marketing term created by Apple, a Retina display is a display with a pixel density high enough that the human eye is unable to make out any individual pixels at a normal viewing distance.
In other words it's a display with no pixellation at all.
The exact pixel density required to be classed as a Retina display varies between devices as it is dependent on normal viewing distance.
So for example an iPhone 4S, which would be held close to the face, has 326 pixels per inch, while an iPad 3 only has 264 pixels per inch, as, thanks to its bigger screen, the optimal viewing distance would place it further away.
This is a particular type of TFT-LCD screen, and has been touted as rivalling AMOLED for image quality. It offers lower power consumption than most LCD technologies, but without sacrificing any picture quality.
Mobile BRAVIA Engine
BRAVIA, an acronym of 'Best Resolution Audio Visual Integrated Architecture', is a Sony brand which has long been used for their televisions.
The Mobile BRAVIA Engine is made up of a number of image processing technologies and is designed to improve images and videos by making them sharper and reducing noise.
It also aims to improve the contrast and create more natural colours. It's not a screen type so much as a suite of post-processing effects which can be turned on or off.
The Mobile BRAVIA Engine is used exclusively in Sony handsets, such as the Sony Xperia S.
This LCD-derived screen technology from LG used on the Optimus Black phone. It's said to offer hugely increased brightness while being extremely energy efficient.
Mobile phone screen resolutions
QVGA (240 x 320)
This is really the bottom end of modern phone resolutions.
Standing for 'Quarter Video Graphics Array', it means essentially a quarter the resolution of VGA and is only normally used for budget phones.
The 'W' here stands for wide, and means that any display that has the same height as QVGA (240) but a greater width, can be described as WQVGA.
The Sony Ericsson Aino has a WQVGA resolution of 240x432.
HVGA (320 x 480)
'Half' or 'half size' VGA, HVGA can actually refer to a handful of resolutions, but the most common one is 320 x 480, which is half the size of VGA, hence the name.
nHD (360 x 640)
This means 'Wider' VGA (Video Graphics Array) and refers to any display with a height of 480 pixels but a width greater than 640 pixels.
The most common WVGA resolution is 480 x 800 and this can be found on lots of smartphones.
The Samsung Galaxy S2, for example, has this resolution, along with the Nokia Lumia 900 and others.
FWVGA (480 x 854)
This stands for 'Full Wide' VGA and unlike WVGA it doesn't need to be cropped to produce an aspect ratio of 16:9.
It's a resolution that can be found, for example, on the Sony Ericsson Xperia Arc S.
qHD (540 x 960)
One quarter of a full HD frame, these high-resolution displays are increasingly being used by smartphones as screens get bigger and bigger.
The HTC Sensation is a prime example of this resolution in action.
DVGA (640 x 960)
XGA (768 x 1024)
This stands for 'Extended Graphics Array' and isn't commonly used in phones, though the forthcoming LG Optimus Vu does have an XGA display.
HD (720 x 1280)
Often referred to as 720p, this is the lowest resolution which would normally be considered high definition.
Standing for 'Wide Extended Graphics Array', this, as you might have guessed, is a widened XGA resolution.
A number of resolutions fall under the WXGA banner, but the only smartphone to currently have a resolution this high is the Samsung Galaxy Note, which has an 800 x 1280 display.
Which is the best mobile phone screen?
When buying a phone, the screen will always be a factor, but it isn't going to be the decider for that many people. The important thing is to understand what you're being offered.
This often isn't helped by obfuscating brand names, such as Apple's Retina display or Sony Ericsson's Reality display. In this case, Apple is referring to the high pixels per inch count of its display, rather than a particular technology, while Sony Ericsson's Reality display with Mobile Bravia screen uses mostly software improvements to the video to achieve impressive results.
In both cases, it's actually LCD technology powering things, which can often be discovered by looking past the marketing and at the specifications.
The ideal option for you may come down to what you use your phone for most. If you like to watch movies and play games on your phone, AMOLED might be the better choice, thanks to its hugely superior contrast ratio compared to LCD.
However, if web browsing and document viewing is more your thing, LCD usually offers slightly crisper text, making it easier to read what's on screen over long periods. In either case, you're unlikely to be disappointed with the best of what manufacturers offer.