Optical medium having a data pattern for detecting an upside-down insertion, and reproducing apparatus for use therewith

An optical reproducing apparatus for an optical medium comprising an information layer, a first transparent plate disposed on a first side of said information layer, a second transparent plate disposed on a second side of said information layer, such that said information layer is interposed between said first and second transparent plates, wherein said information layer includes a first area for recording main information and a second area for recording a data pattern which is readable from both the first and second sides of said information layer, and wherein said data pattern comprises a series of bi-level signals which produce different patterns depending on a direction of reproduction, said optical reproducing apparatus comprising:

• an optical head for reading signals from the information layer of the optical medium;
• a mechanism for moving said optical head above the second area formed in the information layer of the optical medium;
• and
• a decision device for counting the series of bi-level signals of the data pattern read from the second area in the information layer, and determining whether the bi-level signals are increasing or decreasing successively.

An optical reproducing apparatus for an optical medium comprising an information layer, a first transparent plate disposed on a first side of said information layer, a second transparent plate disposed on a second side of said information layer, such that said information layer is interposed between said first and second transparent plates, wherein said information layer includes a first area for recording main information and a second area for recording a data pattern which is readable from both the first and second sides of said information layer, and wherein said data pattern comprises a series of bi-level signals which produce different patterns depending on a direction of reproduction, said optical reproducing apparatus comprising:

• an optical head for reading signals from the information layer of the optical medium;
• a mechanism for moving said optical head above the second area formed in the information layer of the optical medium;
• and
• a decision device for detecting the pattern produced by the series of bi-level signals and thereby determining the direction of reproduction from the information layer of the optical medium.