Exposure apparatus, exposure method, recording and/or reproducing apparatus, and recording and/or reproducing method

A control method for a converging lens, comprising the steps of:

• guiding a second laser beam having a different wavelength from that of a first laser beam into a converging lens assembly disposed in a near-field region of a surface to be irradiated;
• adjusting a convergence angle of only the second laser beam incident upon the converging lens assembly;
• detecting a linearly polarized component of a laser beam reflected off a distal end surface of the converging lens assembly;
• and
• controlling the distance between the distal end surface of the converging lens assembly and the surface to be irradiated by moving the converging lens assembly in the direction of an optical axis on the basis of a detection signal obtained as a result of the detection.

A controller for a converging lens assembly, comprising:

• a first laser light source for emitting a first laser beam;
• a second laser light source for emitting a second laser beam having a different wavelength from that of the first laser beam emitted from the first laser light source;
• a converging lens upon which the first laser beam and the second laser beam are incident and which is disposed in a near-field region of a surface to be irradiated;
• a group of convergence angle adjusting lenses for adjusting a convergence angle of only one of the first and second laser beams incident upon the converging lens;
• a detector for detecting a linearly polarized component of one of the first and second laser beams reflected off a distal end surface of the converging lens;
• and
• a controller for controlling the distance between the distal end surface of the converging lens and the surface to be irradiated on the basis of a detection signal from the detector.

A recording and/or reproducing apparatus comprising:

• a recording and/or reproducing laser light source for emitting a recording and/or reproducing laser beam;
• a detection laser light source for emitting a detection laser beam having a wavelength different from that of the recording and/or reproducing laser beam;
• a converging lens assembly upon which the recording and/or reproducing laser beam and the detection laser beam are incident and which is disposed in a near-field region of a recording surface of a recording medium;
• a group of convergence angle adjusting lenses for adjusting a convergence angle of only the detection laser beam incident upon the converging lens assembly;
• a detector for detecting a linearly polarized component of the detection laser beam reflected by a distal end surface of the converging lens assembly;
• and
• a controller for controlling the distance between the distal end surface of the converging lens assembly and the recording surface on the basis of a detection signal from the detector.