| 摘要 |
PURPOSE:To obtain stable glow discharge with less preliminary discharge, by converging UV light, which is generated by preliminary discharge, at a desired position in a main discharge region by pivotable mirror surfaces, and yielding ionization at the position so that most of the UV light contributes to the ionization in the main discharge region. CONSTITUTION:The main discharge of an excimer laser apparatus occurs between main discharge electrodes 1 and 2 and a glow region 3 is yielded. Meanwhile, preliminary ionization generates UV light 6 between preliminary electrodes 4 and 5. The UV light 6 is converged by a reflecting mirror 9 which is provided behind, and a focal point is formed at a point 11. The reflecting mirror is an elliptic mirror. The first focal point is set at a part, where the UV light 6 is generated, and the second focal point is set at the point 11. Then the UV light 6 is efficiently converged in the main discharge region even if the UV light has less discharge power. Thus sufficient amount of ionized electrons can be obtained. When the mirror can be turned around a supporting post 10, the focal point 11 can be adjusted so that the point 11 is located at the desired position between the main electrodes 1 and 2. The main discharge can be performed along the entire length between the main discharge electrodes 1 and 2. |
