An electrostatically latched and magnetically erased MEMS re-writable bitmap image display

Abstract

We propose a new type of re-writable bitmap image display component using the MEMS (Micro Electro Mechanical Systems) -controlled light scattering. The device is made of a light-guided transparent substrate (glass) and a thin sheet of semi-transparent plastic film (PDMS; Poly Di Methyl Siloxane) with magnetic nickel and light-diffusing glass powders formed in an electrostatic parallel-plate actuator. The membrane segment under a moderate drive voltage (110V), is designed to suspend itself at the rest position over the glass substrate, in which an illumination light travels at the condition of internal total reflection. When an extra force is applied for instance, by manually pressing with a glass rod (diameter 1mm), the membrane is electrostatically brought into contact with the glass substrate, where the light scatters through the membrane to the eyes of a viewer. The trace of the glass-rod stroke persists in the membrane as long as the driving voltage is applied. The image can also be partially erased by magnetically pulling up the magnetic membrane using a tiny permanent magnet scanned over the device. In other words, the developed device has a function of blackboard to which the bitmap image data is written manually. Thanks to the simplicity of the structure and operation principle, the device can be made in large area by the recent “Large Area MEMS” such as a roll-to-roll printing, inkjet printing and plastic molding.