A transparent, hard silica glass (SiO
2) layer was formed on a conventional protective coat made of silicone ([SiO(CH
3)
2]
n) on a polycarbonate plate by the 157nm F
2 laser-induced photochemical modification of silicone into SiO
2. An optimum laser irradiation time of the F
2 laser was found to form a crack-free SiO
2 layer. The high optical transparency of the samples in the visible light region remained unchanged after the F
2 laser irradiation. In the Taber abrasion test, the SiO
2 layer markedly reduced the number of scratches, resulting in a low haze value. The haze values of the samples also depend on the thickness of the silicone protective coat underneath the SiO
2 protective layer. As a result, the difference of haze value was successfully reduced to 1.2%, compared with these of the nonirradiated sample and a bare polycarbonate plate of approximately 3.5 and 46%, respectively, which is comparable to the case of a bare silica glass of approximately 0.9%. In addition, the thickness of the SiO
2 protective layer was estimated to be approximately 0.44μm for the 30-s laser irradiation by immersing the samples in 1 wt % hydrogen fluoride aqueous solution and measuring the depth using a surface profilometer.
抄録全体を表示