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Traditionally, digital cameras have used CCD technology to capture images. However CCD presents significant problems for camera phone manufacturers - it requires a relatively high amount of power, is expensive and provides limited resolution. So phone manufacturers are looking to CMOS technology to replace the CCD.

CMOS uses less power and is cheaper to produce. While CCD manufacturing requires a level of expertise that has restricted the number of companies able to enter the market, CMOS an be made on existing memory production lines. CMOS is also less prone to a form of image deterioration known as smear.

The problem with the technology until now has been a low signal:noise (S:N) ratio compared with CCD. This made it difficult to reduce the size of pixels (the pixel pitch) and thereby to increase the resolution or to reduce the size of the CMOS chip.

However, according to a report by

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Nikkei Electronics Asia, CMOS manufacturers say that will all change this year.

'The steady evolution in camera-equipped mobile phones is the key factor in the sharp drop in CMOS sensor pixel pitch,' the report explains. 'Imagers for mobile phones have to be superior to the imaging devices used in digital cameras or camcorders in three ways: they have to be cheaper, less power-hungry and have a higher S:N ratio. The CMOS imager has satisfied the first two criteria for some time, but it required an improved S:N ratio.'

CMOS manufacturers such as Micron Technology expect to be able to match CCD S:N ratios this year, while Matsushita says that it has cleared the obstacles to reducing the pixel pitch still further.

Once this has been achieved CMOS 'will enjoy the unquestionable advantage because of its lower power consumption and fewer parts,' the report says, adding that 'it will not only accelerate new functions and higher performance but also the rate of price reduction'.

Sony's DCR-PC1000 camcorder and Nikon's D2X camera (using a Sony CMOS imager) are among the first devices to deploy the technology.

But mobile phones will be the biggest driver: shipments of camera phones are expected to be three times those of digital cameras in 2005 and competition will be intense.

'As long as development competition for mobile phones continues,' the report concludes, 'it will drive technological innovation.'