ElectronicPaper(e-Paper)

MD MOUZAM ALI IRFAN160311737050

1

Introduction

E-paper also known as electronic paper or electronic ink display.

Unlike conventionalbacklitflat panel displayswhich emit light:E-paper displays reflect light like ordinary paperTheoretically making it more comfortable to readAnd giving the surface a wider viewing angle compared to conventional displays.

Extremely light and flexible.

Construction of E-paperIt has two different parts.Front plane.Back plane.

The front plane consist of E-ink.

The back plane consist of electronic circuits.Back plane is made up of organic thin film transistor arrays which provide voltage needed by the E-Paper.To form an E-ink electronic display the ink is printed onto a plastic film that is laminated to a layer of circuitry.

The front plane consist of E-ink.E-ink is made up of millions of tiny microcapsules.Microcapsules have diameter of the order of 100 microns.Each microcapsule contains positively charged white particles and negatively charged black particles suspended in a clear fluid .Front plane

When a positive or negative electric field is applied, corresponding particles move to the top of the microcapsule where they become visible to the viewer. This makes the surface appear white or black at that spot.

Back Plane Layout

Technologies proposed so farGyricon

Electrophoretic display

Electrowetting

Electrofluidic display

Interferometric modulator (Mirasol)

GyriconIt was the first electronic paper and was developed in 1970s.Consists of polyethylene spheres having diameter between 75-106 micrometers.Each sphere is ajanus particlecomposed of negatively charged black plastic on one side and positively charged white plastic on the other (each bead is thus adipole).These spheres are embedded in transparent silicone made sheet, with each sphere suspended in a bubble of oil so that they can rotate freely.The polarity of the voltage applied to each pair of electrodes then determines whether the white or black side is face-up, thus giving the pixel a white or black appearance.

The spheres of the Gyricon display are trapped in the oil-filled cavities of an elastomer. Positioning them with a positive or negative voltage puts them into the reflecting [left] or light-absorbing [right] black state. Prototypes have been fabricated at Xerox' PARC.Gyricon E-Paper by Xerox

Electrophoretic DisplayThe electronic ink display from E Ink is based on encapsulated electrophoretics--microcapsules containing many tiny white pigment chips, or particles, that are suspended in a blue-black liquid dye.

Applying an electric field moves the particles about; the microcapsules can be switched into the reflecting [left] or absorbing [right] state by applying a positive or negative voltage across the indium-tin oxide (ITO) electrodes.

Electrophoretic DisplayAny kind of electrophoretic display relies on electrostatic migration of light-scattering particles in a dyed colloidal suspension.

When a positive voltage is applied, the particles migrate electrostatically toward the electrode on the viewer side.

If white light-scattering particles are used, a near-Lambertian reflection can be obtained.

When a negative voltage is applied, the particles move to the electrode on the side away from the viewer and become hidden behind the dye; the viewer sees the color of the dye.

Once migration occurs under either polarity and the voltage is removed, the white particles stay in place, creating a bistable memory device.

Electrowetting DisplayBased on the phenomenon of Electrowetting effect- controlling the shape of a confined water/oil interface by an applied voltage.With no voltage applied, the (coloured) oil forms a flat film between the water and a hydrophobic (water-repellent) insulating coating of an electrode, resulting in a coloured pixel.When a voltage is applied between the electrode and the water, the interfacial tension between the water and the coating changes. As a result the stacked state is no longer stable, causing the water to move the oil aside.This results in a partly transparent pixel, or, if a reflective white surface is used under the switchable element, a white pixel.

Electrofluidic DisplaysElectrofluidic displays are a variation of an electrowetting display.

Electrofluidic displays place an aqueous pigment dispersion inside a tiny reservoir. The reservoir comprises