| 摘要 |
<p>PROBLEM TO BE SOLVED: To prevent uncontrollable property for the shape and depth of a rough surface and to completely prevent the production of burr by irradiating a glass substrate having <20 % transmlttance for laser light with laser beams of 400 to 600 nm wavelengths. SOLUTION: It is supposed that projections (A) are produced by the following mechanism. When a glass is irradiated with laser, the temp. in the irradiated part increases and the viscosity in this part decreases to cause local expansion of the glass. The glass builds up on the surface. By rapid cooling just after irradiation, the expanded surface is frozen to form a projection. Recesses (B) are produced by such a mechanism that the glass is further heated to have lower viscosity and the glass spouts on the surface and flows into the surrounding area. By this method, by properly controlling the laser and the glass substrate to be used, absorption of light and conversion into heat is selectively caused near the glass surface and projections and recesses (A) (B) can be stably and effectively formed.</p> |
