(11) EP 3 800 000 A1 (12) EUROPEAN PATENT APPLICATION (19) (57) Itisintended to provide a laserirradiationdevice, whereby it is made possible to irradiate a laser beam optimal to perform roughening treatment for the surface of a member in order to enhance adhesiveness on the surface of the member, and simultaneously, a laser di- ode,evenwhen used as a lightsource ofthe laserbeam, canbe mitigated indamage.The presentlaserirradiation device (10)irradiates a laserbeam (L)atintervalsofpre- determined time. At one time of irradiation, the laser beam (L) has a waveform composed of a former portion (100) and a latter portion (104). In the former portion (100), an increase rate of irradiation intensity per unit time ismaximized on an outsetofirradiation and is grad- ually reduced as the irradiation intensity approaches a maximum. In the latter portion (104), a reduction rate of irradiation intensity per unit time is maximized after the former portion (100) and is gradually reduced as the ir- radiation intensity approaches a baseline current. EP 800 000 A1 FIG. 2 Printed by Jouve, 75001 PARIS (FR) (ALISN3INI NOILVIAVYYI) ALISNSINI IN3JYUNd (54) LASER IRRADIATION DEVICE AND SURFACE ROUGHENING METHOD USING SAME (43) Date of publication:  07.04.2021 Bulletin 2021/14 (21) Application number:  20197577.8 (22) Date of filing:  22.09.2020 (84) Designated Contracting States:  AL AT BE BG CH CY CZ DE DK EE ES FI FR GB  GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO  PL PT RO RS SE SI SK SM TR Designated Extension States:  BA ME Designated Validation States:  KH MA MD TN (30) Priority: 24.09.2019 JP 2019173559 (71) Applicant:  Phoenix Electric Co., Ltd. Himeji-shi, Hyogo 679-2122 (JP) (72) Inventors:  • GOUDA, Tetsuya Himeji-shi,, Hyogo 6792122 (JP) • WATANABE, Kana Himeji-shi,, Hyogo 6792122 (JP) • KINOSHITA, Masaaki Himeji-shi,, Hyogo 6792122 (JP) (74) Representative:  Horn Kleimann Waitzhofer  Patentanwälte PartG mbB Ganghoferstrasse 29a 80339 München (DE) B23K 26/0622 (2014.01) B23K 26/352 (2014.01) C09J 5/02 (2006.01) (51) Int Cl.: