Patent ID: 8867320

Claim:
A timepiece cover glass used in a timepiece in which a solar battery is provided, the timepiece cover glass covering the solar battery, the timepiece cover glass comprising: an antireflective layer being formed on at least both sides of the timepiece cover glass, reflectance of the timepiece cover glass being a smallest for light with a first wave length, a sensitivity of the solar battery being largest for light with a second wave length. an absolute value of a difference in nano meter being equal to or less than 40 nano meter, the difference being between a largest wave length and a smallest wave length among the first wave length in nano meter, the second wave length in nano meter, and a wave length of 550 nano meter, a luminous reflectance of the timepiece cover glass being 0.6% or less, the luminous reflectance being an average value of reflectances of reference light at wavelengths of a visible light range, which are modified according to luminosity.