| 摘要 |
PURPOSE:To improve the light utilizing efficiency of an optical head and also secure a superior spot by increasing the effective diameters in the parallel direction and decreasing the effective diameter in the vertical direction respectively to the junction surface of the emitted beams from a semiconductor laser. CONSTITUTION:A beam shaping prism 7 has two surfaces (the 1st and 2nd surfaces) sloped to the optical axis of the prism 7, and the sloping directions of both surfaces are orthogonal to each other. In other words, the optical axis of the prism 7 is made parallel to an axis X, and the axes Y and Z are defined as the directions orthogonal to the optical axis of the prism 7. The 1st surface is parallel to the axis Z and is sloping surface to the axis Y, and the 2nd surface is made parallel to the axis Y and sloping surface to the axis Z, respectively. For the prism 7 having two surfaces, the light is made incident on the 1st surface so that the elliptic minor axis of the elliptic polarized light (L1<L2) are in parallel to the XY plane and the XZ plane, respectively. Thus, the minor axis direction of the elliptic parallel light is prolonged on the 1st surface with the major axis direction compressed on the 2nd surface, respectively. Then, the emitted light can be shaped into the circular parallel light. |
