Washing machine having optical sensor for detecting light permeability of detergent solution

摘要

A washing machine apparatus includes an optical sensor which detects a light permeability of a liquid contained in a washer tank and a volume sensor which detects a volume of laundries contained in the washer tank. A minimum washing time and a maximum washing time of a washing cycle are set based on the detected volume of laundries. During the washing cycle, at a saturation time in which the detected light permeability becomes relatively constant, an overall light permeability change is detected. A remaining washing time is set based on the thus detected overall light permeability change, so long as the total washing time falls within the minimum and maximum set in accordance with the detected volume of laundries.