| 摘要 |
<P>PROBLEM TO BE SOLVED: To share optics, such as an aberration correction means for correcting aberration, and to form a satisfactory spot on the recording surface of a blue-based/DVD- based/CD-based optical record medium. <P>SOLUTION: Aberration is detected by a detection means, including a luminous flux division means 109 and a light-receiving element 110, and is corrected by the aberration correction means 401 for adjusting the interval of two lenses. A 1/4 wave plate for converting light into polarization from a straight line to a circle and from the circle to the straight line is provided, and a sufficient quantity of light and the noise of returning light to a semiconductor laser 101 are reduced by a polarization separation optical system, that is combined with a polarization beam splitter 103 to the blue-based optical record medium. The polarization separation optical system with respect to the DVD-based optical record medium for carrying out polarization selection with a hologram 201b is obtained. Aberrations generated by manufacturing errors and variations in the optical record medium 107 enables the wavefront of the returning luminous flux to be distorted, and reduces the amplitude level of the read signal of the optical record medium 107. The amplitude level is detected, and spot formation is carried out on the optical record medium 107 at a maximum level position for optimizing the shape. <P>COPYRIGHT: (C)2004,JPO |
