Patent ID: 9656349
Date: 2017-05-23
CPC Classifications: B23K,G02B

Claim:
1. A laser processing apparatus comprising: a processing head configured to irradiate a workpiece with a laser beam; a light-focusing optical section provided in said processing head, the light-focusing optical section configured to focus a laser beam having a diffusion angle, the laser beam being supplied from a laser source and entering said processing head, and to enable the laser beam to be emitted from said processing head as the laser beam having a convergent angle; and a transmissive optical member provided in said processing head, the transmissive optical member configured to be located at an upstream side of said light-focusing optical section as seen in a traveling direction of the laser beam so as to transmit the laser beam while keeping said diffusion angle constant, before and after transmission, or alternatively, the transmissive optical member configured to be located at a downstream side of said light-focusing optical section as seen in a traveling direction of the laser beam so as to transmit the laser beam while keeping said convergent angle constant, before and after transmission; wherein said transmissive optical member includes a focused-beam diameter increasing part configured to increase a focused beam diameter of the laser beam transmitted through the focused-beam diameter increasing part, as compared to a focused beam diameter of the laser beam in a case where the laser beam is not transmitted through the focused-beam diameter increasing part but is focused by said light-focusing optical section; wherein said focused-beam diameter increasing part comprises a rotationally-symmetric conical plate portion of said transmissive optical member, the conical plate portion being oblique to a symmetry axis and having a uniform thickness; and wherein said transmissive optical member is located at a position where the symmetry axis of the conical plate portion coincides with an optical axis of said light-focusing optical section.