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

An optical information reproducing apparatus comprising:

• an information obtaining device configured to obtain information about a wavelength of a reference beam at recording time from a recording medium which stores main information recorded as a pattern corresponding to interference between an information beam and the reference beam by a main information recording device and information about the wavelength of the reference beam at the recording time recorded by a wavelength information recording device;
• a main information reproducing device configured to obtain the main information recorded on the recording medium by applying a reference beam at reproducing time;
• a temperature determination device configured to determine an aiming temperature, which is a temperature of the recording medium suited to reproduce the pattern, on the basis of difference between the wavelength of the reference beam at the recording time and the wavelength of the reference beam at the reproducing time;
• an incident angle determination device configured to determine an aiming incident angle, which is an incident angle of the reference beam at the reproducing time suited to reproduce the pattern, on the basis of the difference between the wavelength of the reference beam at the recording time and the wavelength of the reference beam at the reproducing time;
• a temperature control device configured to control the temperature of the recording medium so that the temperature of the recording medium is generally equal to the aiming temperature;
• and
• an incident angle control device configured to control the incident angle of the reference beam at the reproducing time so that the incident angle of the reference beam at the reproducing time is generally equal to the aiming incident angle.