This document encompasses key characteristics of primary optical elements (lenses and mirrors) and lens or mirror parquets for concentrator photovoltaics including: optical performance, mechanical geometry, mechanical strength, materials, and surface morphology. The document identifies the essential characteristics, the corresponding quantities of interest, and provides a method for measurement of each quantity.

This document allows lens and mirror manufacturers, concentrator module manufacturers, test laboratories and other interested parties to define lens/mirror qualities and inspect lenses and mirrors. There are no pass/fail criteria associated with the document.

This document defines the test conditions rather than to specify the precise setup of a measurement apparatus. For example, this enables laboratories to acquire reliable and comparable measurement results irrespective of the existing large variety of experimental setups for focal spot characterization. High priority is given to comparable and reproducible measurements of the irradiance distribution in the focal plane and of the optical efficiency. This requires trade-offs that reduce the similarities to outdoor conditions. Furthermore, it is intended not to refer to properties of specific solar cells as this document is dedicated to concentrator optics.

The terms for lenses are applicable for mirrors, unless otherwise specified.