摘要 |
An improved partial reflector is disclosed in which the reflector is configured to provide selected levels of reflectance, transmittance and efficiency that are substantially uniform over the visible wavelength range of 400 to 700 nanometers. This result is achieved using a special three-layer coating that includes a metal layer sandwiched between two metal oxide dielectric layers having relatively high refractive indices >2.0. Advantageously, the three layers all incorporate the same metal, preferably niobium. |