Project Description

Ceiling mounted Large Area IR solar simulator

This solar simulator provides illumination in the Infrared wavelengths  with high spatial uniformity and depth of field

Custom Large Area

Client Requirements 

The second order was placed after a few months of the completion of the previous system. The client approached Sciencetech to custom build a second solar simulator to be installed in their research and development laboratory. The second system was requested to be hung from the ceiling in order to accommodate the end users’ testing setup which occupied the floor space of the lab. Moreover, they required higher spatial uniformity to be achieved for the target three dimensional volume.

Therefore the initial system was re-designed so that the simulated sun light directed downwards towards a vertical target plane from top of a 2m distance at a 30 degree angle.

This light source was especially designed with optical corrections to overcome the lack of symmetry. It was a revised and an improved solution to the optical design of the previous system.

Specifications Description
Target Area Illuminates a 1.5m x 1.5m
Work Distance Solar simulators to be 2.1 m above the floor and 0.8 m above the centre of the target plane
Spectrum Class A, (ASTM) Wavelength range : 700nm to 1100nm
Intensity Equivalent to 0.6 suns irradiance in the range of 700nm to 1100nm wavelength spectrum. 
Uniformity 1m x 1m: ±5% (ASTM)  |   1.5m x 1.5m: ±30% (ASTM)
Depth of Field ±15cm, with change ≤ ±5% Intensity (ASTM)
Attenuation 10 steps, 0.1 suns to 0.6 suns
Temporal Instability Class A (ASTM)
System Warm Up ≤ 15 seconds

Various new designs were proposed to improve the spatial uniformity of the output light. This also required the optical axis of the light source to be at an angle and laterally above the target plane which further complicated the task.

New designs were brainstormed and evaluated for their performance. Each idea was prototyped and various parameters were changed to assess the effects on the spatial uniformity. The idea that showed the most promise was changing the lateral and angular position of the output lens of the system. This idea was then modeled using optical modeling software to better understand the effect on the spatial uniformity. Once the idea was better understood, it was further optimized using the optical modeling software to meet the specialized needs of the system.

The idea then moved to the mechanical design phase. A way to easily reproducibly adjust the output lenses was required. Various methods were investigated and a custom lens holder with specific lateral and angular adjustment capabilities was developed so that the fine adjustments required of the output lens could be achieved to produce a spatially uniform target plane that was not perpendicular to the optical axis of the solar simulator.

The overhanging solar simulator system as envisioned in the end users’ facility

The mechanical drawings of the six overhanging projector units directed at the target plane

Optical ray tracing model for the projectors

This new system incorporated five projector systems with the ability to upgrade to 6 units based on power requirements of the end user. Each projector system contained 2 kW QTH lamps with specialized filters to create the necessary spectral output.

Target area consisted of 1m x 1m with +/-5% non-uniformity. Depth of field was +/-15cm with no change larger then +/- 5% in the non-uniformity specifications.

As before, the end users required only the IR portions of the solar spectrum with a class A spectral match which was achieved in the final outcome. The IR wavelength portion of the solar spectrum was provided from 700-1100nm. The end users required the output power to correspond with 0.6 suns. Therefore the irradiance was adjustable from 0-0.6 suns in a minimum of 10 steps.

Spectral output of the IR producing solar simulator, super imposed on to the AM1.5G solar spectrum

Temporal stability was categorized as ASTM Class A with a design improvement to reduce noise levels produced by the past system. A feedback system was also included in the system with a Sciencetech calibrated solar cell to control and monitor intensity variations within the light sources.

Sciencetech successfully completed all the requirements of the solar simulator. The final acceptance testing was conducted and approved at the end users’ facilities and the system was successfully installed by our team of support engineers. The end users were extremely impressed with the design and workings of the system.

We recently received a third  order from the same clients for a similar solar simulator system.

The final product containing the six QTH projector units illuminating a 1.5m x 1.5m target area

The six projector unit assembly mounted on to an overhanging shelf for illumination

If you have further questions about this project, do please feel free to contact us at info-cs@sciencetech-inc.com

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