E-paper or electronic paper is a special type of display that does not need electricity to sustain the displayed text and image. Just like real paper, the displayed image resembles ink on paper (hence the name). Unlike traditional LCD or OLED display, it does not emit light but reflects light. This characteristic makes e-paper display very comfortable to read even under direct sunlight (refer Fig. 1). Unlike LCD or TFT display, e-paper also does not require a backlight.
The displays are made of millions of minuscule capsules filled with a clear fluid containing microscopic particles of different colours and electrical charges (refer Fig. 2). Electrodes located above and below the capsules move up and down when a positive or negative electric field is applied, making the surface to reflect a certain colour. The displays can hold static text and images for months without electricity. That is, it can retain text and images even when power is off.
Fig. 2: Scheme of e-paper display (Credit: smartcity-displays.com)
However, it has many disadvantages as well. That include its high cost as compared to other displays, slow to update text and images, less memory, among others.
Advantages of E-Paper Display
- Consumes less power
- Display stays for a long time without power
- Ideal for low-power projects including Arduino, NodeMCU and other embedded prototyping boards
- It is available in multiple sizes
- It is a high-definition and paper-like appearance display
Disadvantages of E-Paper Display
- Display is slow to update
- Not suitable for animation or fast-changing displays
- Costlier as compared to LCD and other similar size displays.
- Currently, it has limited software library and supports very few fonts
- It has less memory