There are different types of solar simulator, each with technical specifications designed to fit particular applications. The various types are often separated by the type of exposure in use—flashed, continuous, and pulsed.
New scientific breakthroughs arrived and Ushio’s attention shifted away from the standard halogen and xenon lamps. In the new age of solar simulation technology, solid state lighting takes center stage. Ushio’s Epitex LEDs offer a flexible pulse drive and spectrum, as well as a lifetime that far exceeds its predecessors.
Ushio’s LEDs exceed requirements for solar simulation
Sunlight is officially defined under the Air Mass 1.5 Global (AM 1.5G) Reference Spectrum. Under AM 1.5G, one Sun equals an irradiance of 100 mW/cm². The International Electrotechnical Commission (IEC) described the properties of the natural sunlight that penetrates our atmosphere in IEC 60904-9; therefore, any industry-standard solar simulator must meet or exceed the standards laid out by those guidelines.
As you can see, a large portion of the sunlight reference spectrum falls within the SWIR region, but not exclusively, making Ushio’s entire LED collection (365–1750 nm) a crucial component of any next-generation solar simulation system.
Under IEC 60904-9, the overall performance of solar simulators are measured and rated by three metrics:
- Spectral match to natural sunlight: A sun simulator must also closely match the AM 1.5G spectrum, especially between 300 and 1200 nm. For the highest class of sun simulators, the spectrum variance should not exceed ±12.5% in each wavelength range.
- Uniformity of irradiance over the illumination area: The irradiation of any substrate, such as a typical 200 mm² solar cell, must remain within ±2% uniformity over the surface too.
- Temporal variability of irradiance: Meanwhile, the temporal stability of the irradiance is the final important factor. The irradiance power must fluctuate as little as possible during the course of the simulation. Therefore, a measurement is taken to detect maximum and minimum levels of irradiance during the simulation. This gives a fairly accurate idea of how temporally stable the irradiance is.
Discharge lamps vs LEDs:
Where is solar simulation technology going?
When working with previous Ushio clients such as ESA, NASA, and JAXA, pulsed xenon (Xe) short arc and metal halide (MH) discharge lamps dominated solar simulation; however, these technologies are susceptible to a few disadvantages:
- Costly filters are required to align with AM 1.5G spectrum
- Thermal management required to cope with excessive heat production
- Limited pulse width (PW) control
- Short lifespan
In the new SSL generation, an array of LEDs can adequately cater for the AM 1.5G standards while avoiding those issues. The main advantages of LEDs as a solar simulation light source are:
- Spectral flexibility: Increased spectral match precision and allows the reproduction of various real-world irradiation conditions
- Pulse drive flexibility: LEDs offer a freely-adjusted pulse width
- Built-in thermal management: Some LED packages have a copper heatsink or a ceramic base to safely dissipate excess thermal energy
- Longer lifespan: LEDs save on maintenance, reduce downtime for replacements, and minimizes recalibration time
Industries using LED solar simulators
- Aerospace
- Automotive
- Biomass
- Cosmetics
- Environmental Science
- Material degradation
- Photochemical catalysis
- Photovoltaics (PV) production and testing
- Plastics, paints, lacquers, varnishes, and other coatings
- Quality assurance
- Sunscreen research & development
- Textiles industry
Which LEDs are most ideal for solar simulation?
Ushio’s wider Epitex series offers single- and multi-chip LEDs covering wavelengths from 365 nanometers (nm) to 1750 nm; crossing through ultraviolet (UV), visible light, and SWIR region. While there are many different types of LED package, the high-powered SMBB and EDC series’ are the most suited to solar simulation applications.
Contact Ushio about solar simulation solutions
If you would like to make an inquiry regarding the role Ushio’s SWIR LEDs in solar simulation applications, contact Ushio’s regional experts via the following link:
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