![Sample our Physical Sciences journals, sign in here to start your FREE access for 14 days]({"type":"image" , "src" : "/sda/110819/TOC-Subject-Sample-2021-Physical-Sciences.jpg"})
Abstract
A new phototherapy unit for personal and home application is developed based on red and infrared LEDs. The wavelengths of the LEDs used are 660 nm for red light and 840 nm for infrared. The array of red and infrared LEDs were designed to generate mixture of red and infrared light and the current flowing through red and infrared LEDs were driven by using micro control unit (MCU) so that the light output and the heat generated from LEDs could be controlled in order not to exceed the certain limit. Light output from the personal phototherapy unit depends on the current flowing through red and infrared LEDs. The current can be controlled by MCU and constant current LED driver ICs by adjusting the duty ratio of the driving pulse generated by MCU and the operation time of the phototherapy unit is also controlled by MCU. The average red and infrared light output from the phototherapy unit developed for personal application was set to 50 mW/cm2. The surface temperature of the phototherapy unit after 10 minutes operation did not exceed 41°C at the light output of 50 mW/cm2 while LEDs were in contact with the skin.