Focusing and imaging compatible objective lenses for pixel-based and/or bit-based optical data recording and retrieval

摘要

A low cost and lightweight interchangeable lens system is provided. The lens system includes two aspheric elements that is usable both for page-based and bit-based data storage systems. The lens system has a large field of view up to ±50 degrees and a high numerical aperture up to 0.8. The invention reduces cost and weight of the objective lenses and is usable with the servoing technology. The invention provides a long working distance of 20% of the focal length and provides sufficient physical space to accommodate media and aberration corrections, which enable a media interchangeable and compatible system among the both optical recording formats.