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From the early ground-and-polished prism facets of glass lighthouse Fresnel lenses to modern microreplicated flexible Fresnel lenses for solar concentrators, new applications of prismatic optical components for light control are constantly being developed. In addition, innovations utilizing single and compound prismatic and reflective optical components are emerging in the fields of metrology, polarization control, projection systems, and illumination and display lighting, among others. Several significant applications which may indicate future trends are:

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This paper describes some new configurations for linear incremental or Fresnel refractors and reflectors for solar energy concentration. The first system, a reflex type lens, uses crossed linear echelon elements and has convergence power in two dimensions. This refractor /reflector concentrates solar radiation to a spot focus. Large area solar concentrators can be sectionally constructed to provide high power solar flux concentration. The second type of echelon reflector forms a linear focus of incident solar radiation. The reflector is selectively tilted with respect to incoming solar radiation, such that the design eliminates all riser step blockage of radiation at the reflecting echelons. This results in a higher efficiency concentrator than is achievable with a normally oriented linear focus concentrator. Design parameters and a ray trace analysis are presented for both concentrator systems. SOLAR RAY SPOT FOCUS SPIE Vol. 161 Optics Applied to Solar Energy IV (1.978) / 23Abstract This paper describes some new configurations for linear incremental or Fresnel refractors and reflectors for solar energy concentration. The first system, a reflex type lens, uses crossed linear echelon elements and has convergence power in two dimensions. This refractor/reflector concentrates solar radiation to a spot focus. Large area solar concentrators can be sectionally constructed to provide high power solar flux concentration. The second type of echelon reflector forms a linear focus of incident solar radiation. The reflector is selectively tilted with respect to incoming solar radiation, such that the design eliminates all riser step blockage of radiation at the reflecting echelons. This results in a higher efficiency concentrator than is achievable with a normally oriented linear focus concentrator. Design parameters and a ray trace analysis are presented for both concentrator systems.

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