Fujitsu's R&D (research and development) centre has created software that can display small letters legibly on compact devices such as mobile phones and PDAs (personal digital assistants).

Fujitsu's technology is particularly suitable for double-byte languages, such as Japanese, Chinese, Arabic and Hangul, according to Nobuaki Usui, chief researcher of the input and output research division of Fujitsu. The software can display small double-byte language fonts, for example, it allows characters used in Japanese 'kana' text to be represented in a clear and readable fashion, Fujitsu's statement said.

Usually, a coloured pixel on a computer screen is represented with a mixture of three primary colours — RGB (red, green and blue). In a flat-panel display, every pixel consists of three vertical strips, each representing one of these three colours.

As letters are formed using many of these pixels, the smaller the letters get, the more distorted the edges of the letter appear on a screen. Up until now, this problem was solved by using greyscale, changing the density of each pixel's blackness. But this technique sacrifices the sharpness of a letter's edge.

Fujitsu's solution to this problem is to treat each colour strip as an individual pixel to give finer control over the contours of a letter. The letters will have red, green or blue edges, but these will be imperceptible to the human eye.

This means the technology doesn't need to combine three strips to make up one colour, can treat each colour strip independently and offer 256-scale colour for each pixel strip, Usui said.

Also, as Fujitsu technology controls the brightness of each colour strip next to the pixel, this enables it to accurately display the contours on the edge of a letter.

So jagged parts of a complex letter or symbol, such as a Chinese character, can be rendered more clearly by contouring its shape with a colour strip rather than surrounding the letter with combined colours of pixels, especially when the letter gets smaller.

Fujitsu hopes its font display technology will be adopted by makers of mobile devices, such as PDAs and mobile phones, Usui said. On a PDA screen, which normally has a maximum resolution of 100dpi (dots per inch), Fujitsu's font display technology can present text as small as five-point size in a readable style, he said.

Fujitsu plans to commercialise this font display technology within one to two years, added Usui.