Up until now auto focus has been carried out either by DC motor or Ultra Sonic / Silent Wave Motors, however a new innovation noted by Monty Solomon and reported in todays New Scientist may offer another option, especially for ultra-compact lens systems. A company called '1 Limited' of Cambridge, UK has developed a sheet of piezoelectric ceramic material which can move whatever is placed on it (by using a grip and shift type movement), roll it into a cylinder and you could move a small camera lens up or down the cylinder (zoom or focus). At the moment this technology is aimed at camera phones however I have no doubt that it could be important for lens systems in ultra-compact cameras.

Click here for the original article in todays New Scientist

Click here for '1 Limited'
(note that there is currently no information on this specific technology yet on their website)