Fisheye lens design for solar-powered mobile ultrasound devices.

Abstract

BACKGROUND: Compared to benchtop ultrasound machines, mobile ultrasound machines require portable batteries when acquiring information regarding human tissues during outdoor activities.OBJECTIVE: A novel fisheye lens type was designed to address the charging issue where it is difficult to constantly track the sun. This method does not require the use of a mechanical motor that constantly tracks the sun to charge the portable batteries.METHODS: To obtain an optical solar power system, the numerical aperture (NA) and field angle must be increased. Therefore, we use the fisheye lens with the largest field angle.RESULTS: The NA of the designed fisheye lens system reaches 0.75, allowing light collection of approximately 48. Additionally, the efficiency ratio of the central and surrounding areas also satisfies more than 80% at a field angle of 85 and more than 70% at field angles of 85 to 90, respectively.CONCLUSIONS: We designed a novel fisheye lens for solar-powered mobile ultrasound machines used outdoors.