2015 年 81 巻 4 号 p. 349-355
Laser joining between two non-alkali aluminoborosilicate glass sheets was conducted using vanadate glass frit, which had lower melting point (m. p.) than substrates, as an insert material. In order to investigate the optimal joining conditions, the laser power and scanning speed were varied using circular and elliptical shaped laser beams in the joint experiment. Experimental results showed that the excess power irradiation produced a lot of babbles in the joint area, and insufficient power caused a rapid detachment just after joining. However, these defects were suppressed by elliptical beam irradiation. High-speed camera observations suggested that the elliptical beam irradiation contributed to the slower cooling of molten insert glass compared to the case of circular beam irradiation. Numerical calculation of temperature distribution around laser irradiated area was also carried out using finite difference method. Calculated results showed that the melting time in the case of elliptical beam was 2.5 times longer than that of circular beam. Therefore, the elliptical beam is more applicable to the sealing between two glass substrates.