Japanese designer Nendo has designed a flashlight using electronic paper. The LED lamp has its brightness controlled by how tight the paper is rolled and offers two colour temperature. The design can also be combined with a stand to make a desk lamp.
“After testing various types of paper, we selected YUPO paper by Takeo that is used in ballot paper for elections. The paper is also hard-wearing, water resistant and therefore also suitable for industrial applications,” says Nendo. “The circuits on both sides of the paper were printed with a checker pattern, and two button cells and seven LEDs were glued on with conductive adhesive. The resistance was changed by varying the path length of each LED by adjusting how tight you roll the paper, enabling the lighting to be controlled. The longer the path the higher the resistance, conversely the shorter the path the lower the resistance.”
This simple circuitry means that the light emitted is dimmer when more loosely rolled and more intense when tightly rolled. Also, the colour temperature of the light is affected by the way you roll the paper. “When the paper is wrapped with the surface adhered to the LED facing upwards, the light turns into a warm orange colour,” says Nendo. “When the paper is rolled inside out, the light turns into a white colour. In this way users can enjoy two types of colour temperature.”