| 摘要 |
PURPOSE:To obtain a tacking error signal of a zero-order beam unchanged by a change in a tangential skew angle to a recording medium by providing a light shield so that both side beams of a reflected beam of a recording medium are not made incident to an irradiated end face. CONSTITUTION:When a straight line connecting a center beam La and both side beams Lb, Lc toward a semiconductor laser element 1 is nearly orthogonal to an active layer 1d, for example, the light shield 9 is provided by prolonging a part of a heat sink 8, a window 9a is formed to a part of the active region 1d to the laser beam irradiating part to ensure the irradiation of a laser beam L. Then the beam reflected on a recording medium 6 and going to the semiconductor laser element 1 through a diffractive grating 3 is reflected irregularly in the light shield 9. Thus, the tracking error signal of the zero-order beam of a head OH unchanged by a change in a tangential skew angle to the recording medium is obtained. |
