Patent ID: 7190661

Claim:
A structure for storing selectively retrievable data comprising a data layer of substantially uniform composition, said data layer having: a. a first level; b. a second level substantially parallel to said first level and vertically displaced from said first level in a first direction; c. a third level substantially parallel to said second level and vertically displaced from said second level in said first direction; d. a first feature, said first feature elongated and three-dimensional, at least a portion of said first feature vertically extending from said second level to said third level, said first feature having a first principal axis substantially parallel to said second level, a transverse axis substantially normal to said first principal axis and parallel to said second level, and a vertical axis substantially normal both to said first principal axis and to said second level, said first feature characterized in that: (1) the transverse extent of said first feature is less at said third level than at said second level; (2) the transverse extent of said first feature at said second level, measured from one side of said first feature to the opposite side of said first feature, including any displacement of said first feature from said second level in a second vertical direction opposite said first direction, is microscopic; (3) the length of said first feature from one end of said first feature to the opposite end of said first feature, along said principal axis, including any displacement of said first feature in said opposite vertical direction, is not more than approximately 4 microns; and (4) the outer shape of said first feature, defined by a transverse section thereof, displays no substantial slope discontinuity from the point at which said first feature begins its displacement from said second level, at one transverse edge of said feature, until the point at which said displacement from said second level ends at the opposite transverse edge of said first feature; and e. a second feature, wherein: (1) said second feature comprises an elongated, three-dimensional region extending from said first level to said second level, a portion of said elongated region having a second principal axis substantially parallel to, and approximately aligned transversely with, said first principal axis; (2) the transverse extent of said second feature is less at said second level than at said first level; and (3) the transverse extent of said second feature at said first level, measured from one side of said second feature to the opposite side of said second feature, including any displacement of said second feature in said opposite vertical direction, is not substantially less than said transverse extent of said first feature.