Photovoltaic cell having a colored appearance, particularly for a watch dial

US6459035B2 · kind B2 · utility

Assignee

• Asulab S.A. · CH

Inventors

• Yvan Ziegler · Neuchâtel, CH
• Diego Fischer · Neuchâtel, CH
• Eric Saurer · Bevaix, CH
• Rene Viennet · Neuchâtel, CH

Key dates

• Filing date: Dec 18, 2000
• Grant date: Oct 1, 2002
• Expiry date: Dec 18, 2020

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02E10/52

Abstract

There is described a colored photovoltaic cell (1) with a semiconductor, preferably silicon, which has high efficiency and a pleasing colored appearance, allowing it to be used as a dial for a watch or another electronic apparatus powered by the cell. The cell includes a reflective metal substrate (2) serving as the bottom electrode, a stack of hydrogenated amorphous silicon layers forming p-i-n junctions (8), and a transparent top electrode (9). The latter may be coated with a layer (16) of slightly diffusing lacquer, which may be colorless or colored. The respective thicknesses e1 of the top electrode and e2 of the silicon are combined as a function of the refractive indices of the materials so as to produce an interferential reflection in a predetermined reflection spectrum.