Flashlights that have been designed using the technology of Elephantech, that prints electronic circuit boards onto paper,films and cloth using silver particle ink.
After testing various types of paper, we selected YUPO paper by TAKEO that is used in ballot paper for elections.
With YUPO paper, ink sits evenly and the smooth surface ensures the ink and paper can be rounded with minimal force, and are less likely to curl. The paper is also hard-wearing, water resistant and therefore also suitable for industrial applications.
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. Therefore, light becomes dimmer when paper is rolled loosely, and brighter when tightly rolled.
Furthermore, due to the characteristic that the LEDs change color while touching paper, when the paper is wrapped with the surface adhered to the LED facing upwards, the light turns into a warm orange colour and 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. Furthermore, when pushed through a stand with rings attached to the end, it can also be used as a simple desk lamp. Many different applications are possible in the future such as emergency use and disaster prevention.