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A guide to smartphone screens

If you're shopping for a new smartphone, the quality of your new phone's screen should be one of the deciding factors between competing models.

The smartphone display is today one of the most important elements of any new mobile device. With nearly all new phones using touchscreen technologies, the display is more than just a window full of words and pictures, it's the way we interact with the technology we keep closest to ourselves.

(Credit: CBSi)

If you are shopping for a new smartphone this year, there's a good chance the quality of your new phone's screen will be one of the deciding factors between competing models. Below we take a closer look at the main elements of today's best smartphone displays.

Display technologies

Smartphone displays, like notebooks and tablets, are all based on LCD technologies. LCD has a fast refresh rate, which makes it great for mobile technologies that require bright displays with low power consumption.

TFT LCD — thin film transistor displays are easily the most common in smartphones at this time, though manufacturers are paving the way for newer, better performing screen technologies. TFT LCDs are often used in notebook displays as well.

AMOLED — active matrix organic light emitting diode is one of the prominent up and coming display technologies looking to take over from TFT displays.

AMOLED screens are visibly more colourful than TFT displays and have a lower power consumption with thanks to the intriguing fact that the colour black is produced by the OLED being switched off. AMOLED screens have been used by Samsung, HTC, Nokia and Dell to name a few, and continue to be in high demand.

Super AMOLED — Samsung has positioned itself at the forefront of mobile display technologies producing its "Super" variant on the AMOLED display. By combining the touch panel and the top layer of glass, Samsung has created a screen that is visibly more vibrant than previous AMOLED screens.

Super LCD — another contender for screen dominance is Super LCD. A variant of traditional LCD technologies, SLCD offers better contrast and warmer colours than older LCD displays, but is said to drain more power than AMOLED displays.

IPS — in-plane switching smartphone screens are characterised by vibrant colours and excellent off-axis viewing angles. IPS screens are typically more expensive, but the result is a screen you can see clearly from any angle. Apple recently employed IPS technology in the LCD display of the iPad and iPhone 4. This year, look out for LG to join Apple in producing smartphones with IPS screens.

Touchscreen technologies

Smartphone touchscreens are divided by two very different touchscreen technologies: capacitive and resistive touchscreens.

Capacitive — the preferred technology, capacitive touchscreens, are almost always more responsive to user input and allow for the use of multi-touch technologies. Simply put, capacitive touchscreens transfer a small charge of energy from the display to the user's finger when contact is made and the software calculates which specific area of the screen has changed its charge. For this reason only, parts of the human body (or similar materials) can be used on touchscreens, a restriction that can make character-based text input, like Asian languages, more difficult.

Resistive — this technology is comprised of two very thin layers of metal under the glass of a phone's display which collect location data when they are pressed together. This requires the user to apply pressure and often results in a less responsive user experience.

Common screen resolutions

Click image to enlarge (Credit: CBSi)

Aside from the appearance of a screen, the two most important measurements to consider are the size (typically measured diagonally in inches) and the resolution, or how many pixels the screen displays. The resolution of a screen is often referred to as a variant of the classic VGA resolution (640x480 pixels), but we're also seeing companies starting refer to resolution in terms of it as a fraction of full high definition, or 1920x1080 pixels.

  • QVGA: quarter VGA (240x320 pixels)
  • HVGA: half VGA (320x480 pixels)
  • WVGA: wide VGA (480x800 pixels)
  • FWVGA: full wide VGA (480x854 pixels)
  • nHD: one-ninth high definition (360x640 pixels)
  • qHD: one-quarter high definition (540x960 pixels)

These figures only start to mean something when you compare them next to screens of the same size. For instance, a 4-inch QVGA screen will look considerably less appealing than a 4-inch WVGA screen because it has far fewer pixels to cover the same area. These pixels will be visible to the naked eye, while the pixels on the screen with the higher resolution will appear to seamlessly blend together. Though there are many areas in technology where bigger is not necessarily better, screen resolution is not one of them; the more pixels, the better the picture.

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