LASER IRRADIATION DEVICE AND SURFACE TREATMENT METHOD

PROBLEM TO BE SOLVED: To provide a laser irradiation device with an improved treatment capacity for executing surface treatment by irradiating an irradiation object in liquid with a laser.SOLUTION: A laser irradiation device having an irradiation optical system for converging a laser beam to irradiate an irradiation object in liquid is configured such that the irradiation optical system irradiates the object with the laser beam in a state where a surface part at an irradiation object side in a most objective side optical element 323 arranged adjacent to the irradiation object is arranged in the liquid, and a surface part of the most objective side optical element opposite to the irradiation object side, and other optical elements are contained in a housing that is substantially prevented from infiltration of the liquid. The laser irradiation device comprises; liquid discharge means 440 that is provided in the vicinity of an outer peripheral edge of the most objective side optical element, and discharges a liquid flow substantially along the surface part at the irradiation object side; and liquid suction means 450 that is provided in the vicinity of the outer peripheral edge of the most objective side optical element on a side of the objective side optical element opposite to the liquid discharge means with a central part sandwiched therebetween, and sucks the liquid flow flowing substantially along the surface part of the objective side optical element at the irradiation object side.SELECTED DRAWING: Figure 10 【課題】液体中の照射対象物に対してレーザを照射して表面処理を行う際の処理能力を向上したレーザ照射装置等を提供する。【解決手段】レーザ光を収束させて液体中の照射対象物に照射する照射用光学系を備えるレーザ照射装置を、照射用光学系は、照射対象物に隣接して配置された最対物側光学素子３２３における照射対象物側の面部が液体中に配置された状態でレーザ光の照射を行うとともに、最対物側光学素子の照射対象物側とは反対の面部及び他の光学素子は、液体の浸入が実質的に防止されたハウジング内に収容され、最対物側光学素子の外周縁部近傍に設けられ照射対象物側の面部にほぼ沿って液体流を吐出する液体吐出手段４４０と、最対物側光学素子の外周縁部近傍において液体吐出手段に対して対物側光学素子の中央部を挟んだ反対側に設けられ対物側光学素子の照射対象物側の面部にほぼ沿って流れる液体流を吸入する液体吸入手段４５０とを備える構成とする。【選択図】図１０