<p>A substrate is made of a crystallized glass having translucency and an average linear thermal expansion coefficient of - 5 x 10<-7>/ DEG C at 30 to 500 DEG C. The substrate has a first surface (working surface) of a smooth surface having a surface roughness Rmax of less than 0.5 mu m, and a second surface (non-working surface) of a rough surface having a surface roughness Rmax of 4 mu m. A light shielding layer consisting of a light shielding film and an antioxidant film is formed on the second surface of the substrate through sputtering. <IMAGE></p>
