| 摘要 |
<P>PROBLEM TO BE SOLVED: To realize both of high speed recording of a CD and high quality reproduction of a DVD . <P>SOLUTION: In a light emitting part 2 emitting a semiconductor laser beam 4 for CD and a semiconductor laser beam 5 for DVD, when width of an angle formed by straight lines by connecting points at which radiation intensity of the laser becomes 1/2 of intensity in the center of the laser in a plane being parallel to a pn junction plane of the semiconductor is assumed to radiation angle width of the laser, the radiation angle width θ2 of the laser beam 5 for DVD is set to 1.3 times or more of radiation angle width θ1 of the laser beam 4 for CD. <P>COPYRIGHT: (C)2005,JPO&NCIPI |
