| 摘要 |
PURPOSE:To contrive the miniaturization of an optical head and the reduction in weight without wasting a detected light interrupted with a knife edge by composing a turning means of the total reflecting boundary surface of a prism combined so as to form a total reflecting surface and composing a knife edge means of a boundary between the different material parts of the prism member of one side. CONSTITUTION:The optical head is provided with the turning means to turn a part of a detected light 8 in a different direction, the knife edge means provided on one of optical paths for detecting a focus error condition, etc. The turning means is composed of a total reflecting boundary surface 16 of a prism 15 to be provided in the optical path of the detected light 8 and, simultaneously, to be combined so as to form the total reflecting surface, and the knife edge means is composed of a boundary 17 between the different material parts of a prism member 10 of one side to form the boundary surface 16. Thus, the turning means and knife edge means can be formed of the combined prism 15, a part of the detected light cannot be interrupted by the knife edge means, and the optical head can be miniaturized and, simultaneously, reduced in weight. |
