Product development of laser hair removal system for beauty application

Abstract

In recent year, the raising concern towards beauty increases the demand on products for beauty applications. Household devices are developed for users to carry out treatments at home. In this project, a domestic laser hair removal system is developed to provide convenience and effective treatment to users. To make the device portable, a 7.4V, 2400mAh, rechargeable battery is included in the system. A 12V adapter is needed to convert power from socket to 12Vdc for recharging the battery. The charging process requires 3.5hours. The device can work continuously for around 2hours. 808nm high power laser diode is the main component for the system. 2.0V and 3.7A is supplied to the laser diode to generate 3W laser beam. A DC-to-DC converter, with IC model TPS5450 used, is built to convert power from battery to 2.0V for laser diode. The efficiency of the DC-to-DC converter is 86.7%. Pulsed laser with different power levels is used for hair removal. The power of the pulsed laser depends on the frequency and duty cycle of the pulse which is controlled by MCU. A thermoelectric cooling plate (TEC) is used to provide thermal protection to the laser diode. 4.4V and 1.1A is supplied to the TEC to lower the temperature of the laser diode and ensure the operating temperature of the laser diode is less than 40°C. Power conversion from battery to TEC is achieved by the DC-to-DC converter with IC TPS54627 used. The efficiency of the converter is 81.7%.