With new DVD formats entering practical use almost every month, and other of disc technologies continuing to proliferate, demand is strong for extra-dense recording systems. Thus device makers these days are hastening to develop and introduce violet and blue-violet semiconductor lasers, which work on the short wavelengths necessary for enhanced recording density. These lasers are essential devices for the upcoming fine-density, large-capacity disc technologies. These include systems that can record more than two hours of multiple-channel and digital Hi-Vision broadcasts, or other fine-definition image information. Other potential users of violet lasers include home servers and other kinds of large-capacity information storage systems. In February of 1999, Nichia Chemical Industries, Ltd. began offering samples of a gallium-nitride (GaN) violet laser diode for ¥200,000. Since then, other semiconductor makers have been accelerating their development efforts for similar laser diodes. Some contenders, like Pioneer Corp. and Rohm Co., Ltd., are cooperative with each other in developing lasers. Development trends in this arena spark keen interest in the industry. This is especially true among makers who have been following or participating in the progress toward advanced DVDs that offer recording capacities of 15GB or more per single-sided disc. At this level, the disc has sufficient capacity to record standard-definition TV broadcasts for seven hours, or high-definition broadcasts for two hours. Most manufacturers expect these extra-large-capacity discs to enter the practical-use stage between 2003 and 2005.
展开▼
