| 摘要 |
PROBLEM TO BE SOLVED: To perform operation under a similar environment for using a long wavelength by setting a laser diode differential efficiency for satisfying a specific relationship when emitting a laser beam with a short wavelength of a laser diode for accessing. SOLUTION: In an optical head 4 for accessing an optical disk 2 by applying a laser beam being emitted from a laser diode 5 to the optical disk 2, the wavelength of a laser beam being emitted from the laser diode 5 is set to 500 nm or less, and the laser diode 5 should satisfy an expression. In the expression, Rid is the resistance value of the laser diode 5, Pout is light output when writing data to the laser diode 5, SE is the differential efficiency of the laser diode 5, Ith is the threshold current of the laser diode 5, and Vbg is the band gap of the laser diode 5, thus reducing consumption power to at least that of a semiconductor laser diode being applied to an optical disk device or the like according to a long wavelength. |
