US Patent 9335539 Pixel device and display using liquid ink and elastomers

A pixel device using optically active fluid contained within elastomeric materials and actuated through dielectric elastomer membrane is disclosed. The underlying mechanism of optical contrast in this display pixel is the spread and contraction of the fluid contained within a pre-stretched elastomer membrane and a substrate. The actuation mechanism for the fluid flow is a dielectric elastomer membrane coated with compliant electrodes on both sides. When both electrodes are connected to a voltage source, the oppositely charged electrodes attract each other, compressing the sandwiched elastomer membrane in the thickness direction but increasing its lateral dimension. Due to geometrical constraint, the change in the membrane lateral dimension results in the net volume change of the fluid reservoir, causing optically active fluid to move from the display cavity into the fluid reservoir or vice versa. The variation of the amount of fluid in the display cavity corresponds to the variation of optical properties, such as contrast and color, of the pixel device.