As detectors, integrating spheres play an essential role in overall transmittance and reflectance in solar applications. The development of new types of photovoltaic
cell also calls for other forms of measurement. For exampleusing special equipment to measure specular reflectance is common practice when implementing quality assurance
measures for the thin layer deposits found in thin film cells. Measurements need to be performed on ever larger samples, with whole modules (as opposed to cells) now undergoing tests.