| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide an optical head that has a diffraction element which can precisely form a first and a second diffraction gratings in mass production to diffract the first and second laser beams of different wavelengths respectively, and to provide a diffraction element thereof and its manufacturing method. <P>SOLUTION: A diffraction element 6 is arranged in an optical head on the common light path through which the laser beams L1, L2 of different wavelengths pass, and its light transmissive substrate 61 has a light output surface 63 divided into a first and a second diffraction grating areas 64, 65. In the first diffraction grating area 64, a first diffraction grating 66 is formed to diffract the first laser beam L1 and to pass the second laser beam L2 without diffracting. In the second diffraction grating area 65, a second diffraction grating 67 is formed to pass the first laser beam L1 without diffracting and to diffract the second laser beam L2. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
