Optical information recording medium manufacturing method therefor, manufacturing apparatus therefor, and optical information recording and reproducing apparatus

An optical information recording medium having at least two information layer, comprising:

• a first substrate having pits on one side thereof;
• a first information layer formed on a surface of the first substrate and having a predetermined reflectance with respect to a light beam;
• a second substrate having pits on one side thereof;
• a second information layer formed on a surface of the second substrate and having a predetermined reflectance with respect to the light beam;
• and
• a separation layer formed between the first information layer and the second information layer,
• wherein a diffraction of reflected light from the pit of the first substrate is substantially equal to a diffraction of reflected light from the pit of the second substrate.

A method of manufacturing an optical information recording medium having two information layers and capable of reproducing information signals from said information layers by means of irradiating a light beam, said method of manufacturing an optical information recording medium comprising:

• a first film-forming step of forming a first information layer having a predetermined transmissivity and a predetermined reflectance on a first substrate having information pits corresponding to information signals on one side thereof;
• a second film-forming step of forming a second information layer having a predetermined reflectance on a second substrate having information pits corresponding to information signals on one side thereof;
• a step of applying a resin layer, which is transparent with respect to said light beams, to the upper surface of said first information layer or said second information layer;
• an adhesive-bonding step of locating said first information layer and said second information layer to face each other and adhesive-bonding said first and second information layers to each other through said resin layer;
• wherein a diffraction of reflected light from the pit of the first substrate is substantially equal to a diffraction of reflected light from the pit of the second substrate.