The concept of high NA(0.85) aspherical single lens for next generation optical disc system

In high density optical disc systems, several methods have been presented which employ an object lens with NA 0.85. Two element objective lenses with NA 0.85 have been developed and tried for next generation optical disc systems. However, we are sure that a single lens is required which would help to achieve a longer working distance and a smaller diameter because the size and the cost will be major factors in the future of NA 0.85 lenses. Last year we produced a prototype single lens with NA 0.85. Here we introduce the design concept, and also report on the favorable performance of the new lens re-designed for mass production.