Electrophoretic display technology
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This document discusses electrophoretic display technology. It begins with an introduction to electrophoresis, which is the movement of charged particles in a colloidal suspension under an applied electric field. It then describes the basic components and working principle of an electrophoretic image display, which uses a mixture of charged black and white pigment particles suspended in a transparent liquid that can be moved around with an electric field to create an image. Applications of this technology include e-readers, electronic paper, and electronic shelf labels. The technology offers benefits like low power consumption and flexibility but has drawbacks like low refresh rates and the need for ambient light.
Electrophoretic display technology
- 1. Electrophoretic Display Technology Vignesh V Sri Sivasubramaniya Nadar college of Engineering 1
- 2. Content Introduction Electrophoretic Image Display Principle of EID Electrophoretic Ink Properties of E-Ink displays Applications Advantages and Disadvantages Conclusion 2
- 3. Introduction What is Electrophoresis? The phenomenon of transport of charged particles in a colloidal suspension by means of an applied electric field is known as electrophoresis. The term electrophoresis is a composition of 'electro' and 'phoresis', two words that are derived from the Greek words for 'charge' and 'the act of carrying'. 3
- 4. Electrophoretic Image Display A simple EPID cell consists of a thin layer (50 µm) of colloidal suspension sandwiched between the transparent electrode surfaces of two glass plates. 4
- 5. Principle of EID In case of a black and white display, the top substrate is covered with a single transparent electrode, while the bottom substrate contains a complex pattern of line-electrodes. The electrophoretic ink between these electrodes is a mixture of transparent liquid and microscopic charged pigment particles. 5
- 6. Principle of EID The usual choice is negatively charged black particles (carbon black) and positively charged white particles (TiO2). When the bottom electrode is positive, it will attract black particles and repel white particles. 6
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- 8. Principle of EID These white particles gather at the top-electrode, where they reflect incident light in all directions. In the opposite case of a negative bottom electrode pushes the black particles to the surface, where they absorb the light. 8
- 9. Zoomed image of an electrophoretic display 9 Principle of EID
- 10. Electrophoretic Ink Electrophoretic or, electronic ink is the optical component of a film used in Electronic Paper Displays (EPD). It utilizes the same pigments used in the printing industry today. 10
- 11. Properties of E-Ink displays The display is bistable which means that the image on the screen will be retained even when all power sources are removed. The displays are of reflective type. Two pigment ink system i.e., Electronic ink is made up of millions of tiny microcapsules, about the diameter of a human hair. 11
- 12. Properties of E-Ink displays E Ink based displays support a variety of solutions for touch. These solutions include several sensor types: resistive, inductive, capacitive or Infrared. Colour pigmented displays have also been developed. 12
- 13. Electronic paper Electronic paper was first developed in the 1970s by Nick Sheridon at Xerox's Palo Alto Research Center. The first electronic paper, called Gyricon, consisted of polyethylene spheres between 75 and 106 micrometers across. Each sphere composed of negatively charged black plastic on one side and positively charged white plastic on the other 13
- 15. Applications This technology is being used in many devices as of now. Some of them are : Wristwatches Electronic paper Mobile phones Status display in USB E-book readers Electronic Shelf Labels 15
- 16. Advantages High reflectivity of the white state and high contrast. Excellent readability in direct sunlight and in dimmed light under all angles. Very low energy consumption. Flexible displays 16
- 17. Disadvantages They have a very low refresh rate compared to other low-power display technologies, such as LCD. Environmental lighting is needed in some devices. A shadow of an image may be visible after refreshing parts of the screen. 17
- 18. Conclusion Technology giants like Phillips, Sony, LG and others are currently doing researches to over come the disadvantages. With the increasing need of electronic gadgets with a lower power consumption and longer use, this technology can be used as an alternative. Usage of E-papers helps in reducing the usage of ordinary paper and save a lot of natural resources. 18
- 20. Thank you 20