Does the kind of phone screen matter? - Reviews - Cool Gear - Mobile Phones

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This story was printed from ZDNet Australia.
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Does the kind of phone screen matter?

May 08, 2003
URL: http://www.zdnet.com.au/reviews/coolgear/mobiles/soa/Does-the-kind-of-phone-screen-matter-/0,139023387,120274313,00.htm

Does the kind of phone screen matter?

We showcase the most significant screen technologies now showing or coming soon to a phone near you.

It used to be so simple. The mobile phone displays came with black text on dirty green backgrounds. Then we started seeing fanciful blue, amber and white illumination, and backlights that seemed more in place in the discotheque than on a mobile phone. Then finally, it happened, as we knew it had to: Colour seeped into our mobiles.

These days, there are several display technologies battling for a place on your mobile phone, and countless more in development. Here, we showcase the most significant screen technologies now showing or coming soon to a phone near you.

1. Monochrome LCDs
Items harnessing liquid crystal displays (LCDs) are all around us, from calculators to digital watches and, of course, mobile phones. First discovered in 1888 by an Austrian botanist, liquid crystals can be manipulated by electric current, thereby changing their shape. In monochrome mobiles, these liquid crystals darken pixels by blocking out back illumination. One of the greatest advantages of monochrome screens is thus its low power consumption, making it a suitable for mobile phones such as the Nokia 8250.

Over the years, although mobile phones have shrunk, their screens have become larger and sharper with the popularity of text messaging. However, the migration to colour was only a matter of time. In a few years, the monochrome mobile could be almost as rare as a black-and-white television set.

2. Passive-matrix colour displays
Most of the early implementations of colour in mobiles employed passive-matrix technology. Passive-matrix screens harness a grid system using vertical and horizontal wires to direct electrical charges to a certain coordinate--thus lighting up the pixel. Passive-matrix displays, although cheaper to produce, generally have drawbacks such as a slower response time and less bright screens, compared to active-matrix.

One popular form of passive-matrix technology is STN (Super Twisted Nematic). Such displays are found in phones such as the Nokia 7210, Motorola C350, and the Sony Ericsson T310 (left).

3. Active-matrix colour displays
Active-matrix screens make use of TFT (thin film transistor) technology. Commonly found on notebooks, TFTs screens contain a transistor for every pixel, giving rise to sharper and brighter images. However, TFT displays are also more expensive and require higher power consumption. Such displays are therefore mostly found in high-end handsets, including the Samsung SGH-T400 and the Panasonic GD88 (left).

As more and more phones sport advanced imaging functions, the strengths of TFT will make it more and more popular in mobile phones. After all, digital cameras have been using TFT displays for years, and are now migrating to OLED displays.

4. Samsung's UFB
First unveiled March 2002, UFB technology was developed by Samsung SDI display unit. According to Samsung, it took the company a month to decide on the UFB moniker, which stands for "Ultra Fine & Bright". Said to offer rich colours, high response times of active-matrix screens, yet the low power consumption of passive-matrix displays, UFB has seen its introduction in recent Samsung handsets. The overall performance of the displays in the SGH-S300 (left) and SGH-T200 certainly mark the technology as one to watch. Samsung SDI claims to manufacture handset screens for Nokia and Motorola, so it would be interesting to see UFB displays in non-Samsung phones.

5. OLED
Apart from UFB, another up-and-coming screen technology is OLED, or organic light-emitting diode. Although handsets sporting such screens are still scarce, there are a couple on the horizon. The Motorola V600 (left) is reported to sport a OLED display, as is Samsung's upcoming PDA-phone SGH-i500. There are still different forms of OLED that will likely see the market but, in general, OLED screens don't require a backlight as polymers in the display emit light when an electrical charge is applied. Its advantages are lower power requirements and a smaller size.