Rhee et al, US Pub. No.: 2007/0113883, published May 27, 2007, employs Fresnel prism sheets to superpose beams of light on a photovoltaic cell. However, a multiplicity of different types of prism sheets are required to carry out superposition as described therein. Also, the superposing prism sheets are linearly aligned in series as their distance from the photovoltaic cell increases, resulting in a thick panel which is unwieldy for use with a tracker.
A device which is more simple and compact would be desirable.