Night lights are one of the most important tools in every house. They not only provide light throughout the night, but also bring us a sense of security and protection. Besides providing a comforting light, night lights are generally seen as decorations in the room. Traditionally, night lights are light bulbs in nice designs, such as a children's favourite cartoon character or some popular animals, which can bring a special atmosphere in a dark room. In recent years, many LED night lights have become available. They not only last longer, but are shaped like fairy tales, animals and other figures that can better decorate a room. Apart from its decoration effect, the most important role of night lights is to illuminates dark places and to allow children to sleep without fear of the darkness. The brightness of the night lights should be lower than that of the daylight, creating a soothing environment without giving too much stimulation before sleeping. Just like the saying goes, “Light carries dreams and illuminates the dark places,” night lights are indeed an important product in our households.