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In this paper, a miniaturized concentrator photovoltaic (CPV) system is experimentally demonstrated based on a hot embossing silicone lens array with a size of 2 cm × 2 cm. Owing to the small size of the lens array, the total track of the CPV system can be as small as 4 cm. Consequently, the weight of the CPV system can be much lower than conventional bulky CPV system. For harvesting the diffuse solar radiation, perovskite solar cells are mounted adjacent to a multi-junction solar cell. Theoretically, the short-circuit current of the CPV system can be enhanced from 48.1 to 85.5 mA for γ = 0.7. The enhancement can be much higher for off-normal incident light. This kind of hybrid CPV system will be useful for cloudy weather and also useful for compensating the loss caused by the miss-alignment of the tracking module. [ABSTRACT FROM AUTHOR]

We proposed a design for a laser mini-projector with a low speckle contrast value and high contrast ratio that maintains system efficiency. The key design is that two diffusers are located in the two sides of the light tunnel. By vibrating the 30 × 30 diffuser under 100 Hz, the speckle contrast value can be decreased to 2.32% which is invisible to the human eye. Considering the trade-off issue of optical efficiency and speckle noise, the most suitable arrangement with circular diffusers is ‘30 × 30H, 5 × 5. The vibration direction is at the long side of the light tunnel. [ABSTRACT FROM AUTHOR]

The structural parameters of a planar micro-optic concentrator are optimized. First, the direct-loss is minimized by altering the relationship between the f-number of the lenslet, the angle of the micro-structure and the ray paths in the planar micro-optic concentrator. Second, the size of the micro-structure is made equal to the mini-blur size of the lenslet in order to reduce the non-direct loss. Last, the f-number and the entrance pupil diameter of the lenslet are determined by the relationships among the f-number, the entrance pupil diameter, the optical efficiency, the acceptance angle and the thickness of the planar micro-optic concentrator from the optical simulation results. For an optimized planar micro-optic concentrator with a 300× concentration, the f-number of the lenslet, the EPD of the lenslet, the angle of the micro-structure and the thickness of the planar micro-optic concentrator are 2.6, 1.49 mm, 120 degrees and 5.97 mm, respectively. For micro-structures 28.95 μm, 51.24 μm and 88.29 μm in size, the half acceptance angles of the planar micro-optic concentrator are 0.115 degrees, 0.275 degrees and 0.55 degrees, respectively, and the optical efficiencies are 81.23%, 71.92% and 50.02%, respectively. [ABSTRACT FROM AUTHOR]