| 摘要 |
PURPOSE: To provide a compact and sturdy scanner by providing a mirror objective lens with a special element. CONSTITUTION: The objective lens system is a mirror objective lens 10, and is provided with a radiation penetrating body that is stipulated by the first refracting face 12 on the radiation source 9 side and the second refracting face 13 on the recording carrier 1 side. In addition, the mirror objective lens 10 is also provided with the first radiation penetrating diffraction element 30 arranged on the first radiation window 14, and the second reflecting diffraction element 40 arranged on the second reflecting body 16. In this case, the mirror objective lens 10 having a prescribed thickness, the two diffraction elements 30, 40 are situated with a mutual distance larger than the desired minimum distance and also, with the first diffraction element 30 arranged closely to a radiation light source, the element may be designed to be small in dimension. As a result, a compact and sturdy scanner can be obtained. |
