| 摘要 |
PURPOSE:To improve the output characteristic by enabling to effectively utilize the light of a long wavelength and thus reducing the loss of light reflection by a method wherein unevenness is formed on the surface of a substrate by controlling the grain size in the surface. CONSTITUTION:The surface of the titled substrate 1 is processed to a surface of uneven state having roundness. For example, the surface of a ceramic substrate of alumina, etc. is coated with a metallic paste of uniform grain diameter in the range of a grain diameter 0.05-10mum. As the metallic paste, tungsten, molybdenum, nickel, aluminum, silver, titanium, manganese, chromium, cobalt, or the alloy of these is used. Thereafter, the substrate 1 as above-mentioned is obtained by calcining the substrate. At this time, the substrate can be also further plated with nickel and Ti-Ag alloy. The surface of the substrate 1 thus obtained presents unevenness. |
