Interference of converging spherical waves with application to the design of light-readable information recording media and systems for reading such media

An information recording medium readable by an optical reader comprising:

• a transparent substrate having one substantially planar surface and a second surface opposite to said first surface, said second surface formed as a data storage structure including pits and lands, in which the depth of said pits is equal to about:
• 33 λ 2 ⁢ n ⁢ m 1 + M T 2 ,
• wherein λ is a wavelength of the light used to read the information recording medium, n is a refractive index of the substrate, m is selected from a group consisting of odd integers, and MT is a transverse magnification of the reader, wherein said pit depth, d, is selected to satisfy the following condition:
• d<λ/5.3 n
• a light reflecting coating on said second surface for reflecting said light passed through said transparent substrate, said coating conforming to the contours of said second surface so that said light is reflected back through the transparent substrate in accordance with the information recorded by means of said pits and lands.

An information recording medium readable by an optical reader comprising:

• a transparent substrate having one substantially planar surface and a second surface opposite to said first surface, said second surface formed as a data storage structure including pits and lands, in which the depth of said pits is equal to about:
• 34 λ 2 ⁢ n ⁢ m 1 + M T 2 ,
• wherein λ is a wavelength of the light used to read the information recording medium, n is a refractive index of the substrate, m is selected from a group consisting of odd integers, and MT is a transverse magnification, wherein said pit depth, d, is selected to satisfy the following condition:
• d<λ/5.3 n
• a light-reflecting coating on said second surface for reflecting said light passed through said transparent substrate, said coating conforming to the contours of said second surface so that said light is reflected back through the transparent substrate in accordance with the information recorded by means of said pits and lands;
• and
• a protective coating having a first surface conforming to the contours of said light-reflecting coating and a second surface opposite to said first surface being substantially planar.