Optical state recognizer, information processor, and optical state recognizing method

An information processor, comprising:

• an optical pickup comprising:
• a light source;
• a diffraction grating that transmits and diffracts a light beam outputted from the light source;
• a condensing section that condenses a transmitted light beam transmitted by the diffraction grating and a diffracted light beam diffracted by the diffraction grating on a recording surface of a recording medium, the recording medium including a reference recording medium whose recording surface has a specific reflection characteristic and a target recording medium;
• and a photodetector that receives the transmitted light beam and the diffracted light beam reflected by the recording surface of the recording medium to output a predetermined signal;
• and
• an optical state recognizer that recognizes a state of the light beam reflected by the recording surface, the optical state recognizer comprising:
• a reference light intensity information acquiring section that acquires reference transmitted light intensity information corresponding to an intensity of the transmitted light beam reflected by the recording surface of the reference recording medium to a first region and reference diffracted light intensity information corresponding to an intensity of the diffracted light beam reflected by the recording surface of the reference recording medium to a seconds region;
• a detected light intensity information generating section that detects the intensity of the transmitted light beam reflected by the recording surface of the target recording medium to the first region to generate first detected light intensity information corresponding to the intensity of the detected transmitted light beam and detects the intensity of the diffracted light beam reflected by the recording surface of the target recording medium to the second region to generate second detected light intensity information corresponding to the intensity of the detected diffracted light beam;
• and
• a reflected state recognizing section that recognizes a reflected state of the target recording medium on the basis of a ratio of intensity of the reference transmitted light intensity information and the reference diffracted light intensity information, and intensities of the first detected light intensity information and the second detected light intensity information.

An optical state recognizing method for recognizing a state of a light beam irradiated by a light source and reflected by a recording surface of a recording medium, the recording medium comprising a reference recording medium that has a specific reference characteristic and a target recording medium, the method comprising:

• interposing a diffraction grating between the light source and the recording surface;
• setting a transmitted light beam transmitted by the diffraction grating to be reflected by the recording surface to a first region;
• setting a diffracted light beam diffracted by the diffraction grating to be reflected by the recording surface to a second region;
• acquiring reference transmitted light intensity information corresponding to an intensity of the transmitted light beam reflected by recording surface of the reference recording medium toward the first region and reference diffracted light information corresponding to the diffracted light beam reflected by the recording surface of the reference recording medium to the second region;
• detecting the intensity of the transmitted light beam reflected by the recording surface of the target recording medium to the first region to generate first detected light intensity information corresponding to the intensity of the detected transmitted light beam and detecting the intensity of the diffracted light beam reflected by the recording surface of the target recording medium to the second region to generate second detected light intensity information corresponding to the intensity of the detected diffracted light beam;
• and
• recognizing a reflected state of the light beam by the recording surface of the target recording medium on the basis of a ratio of intensity of the reference transmitted light intensity information and the reference diffracted light intensity information, and intensities of the first detected light intensity information and the second detected light intensity information.