Optical Wireless Power Transfer for Endoscopy Systems for Enhanced Safety and Isolation

In a typical endoscopy system, electrical isolation between the endoscope and the video processor (VP) is achieved using galvanic isolators and optocouplers. However, these solutions are not entirely isolated, and there is always a risk of electric leakage. Optical wireless power transfer (OWPT) can help achieve complete isolation by eliminating electrical contact between the power supply and the electronic circuits driving the components that come in direct contact with the patient. An optimal solution would be to achieve optical isolation for both the power and the data path. This study proposes a low-cost solution for just OWPT using an LED array consisting of 27 cool-white LEDs coupled with a silicon-based Photovoltaic (PV) cell. The LED array-PV cell pair was characterized and tuned to drive a camera system in an endoscope. By varying the distance between the transmitter and the receiver and by varying the driving current of the LED array, the complete operating characteristics were determined. The optimal operating point was selected from among the possible combinations where the distance between the transmitter and the receiver is high and the driving current of the LED array is low, providing adequate power to meet the power requirements of a camera system. The operation of a 720p CMOS Camera system with an LED for illumination is demonstrated, showing a successful Optical Wireless Power Transfer. This OWPT implementation enhances patient safety by completely eliminating the electrical path for leakages and interferences caused by any electrical anomaly in the power supply.