Solar-cell watch dial and process for producing the same

摘要

PCT No. PCT/JP95/02158 Sec. 371 Date Apr. 18, 1997 Sec. 102(e) Date Apr. 18, 1997 PCT Filed Oct. 20, 1995 PCT Pub. No. WO96/12989 PCT Pub. Date May 2, 1996A solar-cell watch dial to be disposed on or above a solar cell housed in a watch, the solar-cell watch dial comprising an alumina of the formula Al2O3 whose purity is at least 99.90% and exhibiting a light transmission ranging from 40 to 60%. The invention also includes a process for producing a solar-cell watch dial, which comprises the steps of: mixing together an alumina of the formula Al2O3 whose purity is at least 99.90%, an organic binder and water to thereby obtain an Al2O3 mixture (A); drying and granulating the Al2O3 mixture to thereby obtain a granular material (B); molding the granular material into a plate dial precursor (C); firing the dial precursor at 700 to 1500 DEG C. in atmospheric environment to thereby obtain a preliminary firing product (D); and firing the preliminary firing product at 1500 to 1800 DEG C. under a pressure of 1x10-2 to 1x10-5 torr for 1 to 10 hr to thereby obtain a solar-cell watch dial (E). The solar-cell watch dial of the present invention enables preventing the solar cell from being sighted from outside without hindering the supply of light energy to the solar cell.