| 摘要 |
PROBLEM TO BE SOLVED: To provide a beam focuser for focusing approximately collimated light distributed through an entrance pupil of a predefined diameter, which has a narrower focus area and/or a longer working distance and/or a better mobility relative to a material to be machined.SOLUTION: Disclosed is a beam focuser SF for focusing an incident bundle EB of approximately collimated beams S around an optical axis OA in a focus area around a focal point F. Along an optical path from a light entrance LE to a light exit LA, a first axicon A1 having an axicon angle and then a second axicon A2 having the same axicon angle are disposed on the entrance side, and an imaging optical system L is disposed on the outlet side. The first and second axicons A1, A2 are mirror-symmetrically disposed along the optical axis OA. The imaging optical system L has a focal point F facing the exit LA side of the beam focuser SF.SELECTED DRAWING: Figure 3 |
