Daylight Electroluminescence & Photoluminescence
Imaging System for Photovoltaic Modules

Helios is the complete luminescence imaging system for silicon photovoltaic devices. Helios is designed for electroluminescence (EL) imaging in ambient conditions ranging from total darkness to full sunlight exposure. In addition, Helios effortlessly acquires photoluminescence (PL) images under direct sunlight. The portable system facilitates easy operation at your base or in the field.

The Helios luminescence imaging system enables you to know your cells. The turn-key system incorporates user-friendly software that utilizes the latest hardware-accelerated algorithms to afford fast image processing on a supplied notebook PC, an intelligent DC power supply, and a cooled InGaAs camera for ultimate sensitivity to silicon emissions. Simple field connections between the system’s components are made in seconds. Selection between EL and PL modes is simply made by a flip of a switch on the power supply. Camera resolution, working distance, and input AC voltage are selectable upon system configuration. Image acquisition times are greatly reduced by sophisticated image processing algorithms that minimize imaging noise. Because luminescence imaging depends on ambient conditions, EL image acquisition time increases with incident irradiance while PL image acquisition time decreases with incident irradiance. In the case of EL, incident irradance represents imaging noise while in the case of PL, incident irradiance is proportional to imaging signal. The Helios system is designed to maximize imaging performance in each case given the associated measurement characteristics. The software also improves usability by means of automatic camera exposure-control, including a histogram-weighted setting that maximizes image quality under the majority of conditions. Image acquisition is simply: point, focus, and shoot.

Example EL and PL images acquired by the Helios system are given below. The EL and PL images represent the same area of a commercial PV module.