A nanometer scale polymer pattern was formed on the surface of a glass plate by nano-imprint lithography with the aim of reducing the reflection of light at the surface. Since this polymeric nano-pattern is smaller than the wavelength of light, the effective refractive index near the surface changes gradually, and reduces the amount of reflection. Such a nano-pattern was formed on one or both sides of a glass plate, which will be used as the protective layer for solar cell devices. As a result, a solar cell with a both-side patterned glass plate as a protective layer showed up to 2.5% increase (5.14-5.27%) in total conversion efficiency, compared to a solar cell with a bare glass plate. (C) 2009 Elsevier B.V. All rights reserved.