EINDHOVEN, The Nethelands, June 21 -- Philips says it has demonstrated the world's first fully functional miniature optical disc drive using blue laser technology. The company says as much as 1 GB of data can be stored on a single-sided optical disc of just 3 cm in diameter, matching the size constraints of portable devices such as digital cameras, mobile phones, PDAs and portable Internet devices. According to Philips, the main factor determining the building height of optical disc drives is the optical objective lens system. Through the development of the world's smallest objective lens for blue laser recording, the height of the optical disc drive was reduced to 7.5 mm, from the 12.5 mm or more typical in current drives. The lens was made of plastic instead of glass, allowing greater design freedom and hence a smaller drive height. Another step was the development of an ultrathin version of the actuator that positions and focuses the laser beam onto the optical disc. Using these miniature key components, a first fully functional prototype optical drive of just 5.6 by 3.4 by 0.75 cm3 was realized. Further research is underway to achieve an even higher level of miniaturization. The demonstrator setup, with the driving electronics currently still on a separate board, successfully played back MP3 data from a 3-cm-diameter optical disc.