Patent ID: 7391700
Filing Date: 2008-06-24
Classification: G11B

Abstract:
1. Data retrieval apparatus for retrieving data stored on an information record medium having a plurality of record layers, the apparatus comprising means for irradiating a first record layer with electromagnetic radiation, a detector for receiving an electromagnetic radiation beam reflected back from said information record medium and for retrieving said data therefrom, said radiation beam comprising radiation reflected back from said first layer and radiation reflected back from one or more of the other layers of the information record medium, the apparatus further comprising spatial filter means arranged and configured to spatially filter said radiation beam so as to cause the radiation reflected by said first record layer and said radiation reflected by any of the other record layers of the information record medium to be spatially separated, and means for selectively eliminating at least a substantial portion of said radiation reflected back from said other record layers from said radiation beam prior to retrieval therefrom of said data.