An introduction to e-ink

January 30, 2021

As I’ve written in my other post, I really like e-ink displays. They’re easy on the eyes, making for a better reading experience.

So, what’s an e-ink display and how does it work? E-ink differs from traditional displays (like those found in iPhones, LCD screens etc) in that they are nonemissive.

To understand it all, we should first understand how we see things.

How we see things

When we see something, what’s really happening is that photons (particles of light) from a light source, usually the sun or perhaps your ceiling light, arrives on the object, and reflects onto our eyes for our brains to decode.

But when you’re looking at a screen, you’re looking at a grid of lights that are packed really tightly together.

Simplified idea of how an emissive screen works

Each grid is composed of a subpixel red green or blue. Together in large amounts and packed densely, we can form images.

With a nonemissive display like an e-ink display however, there is no light under the screen.

Simplified idea of how a nonemissive screen works

Grids of tiny spheres are filled with ink that’s half white and half black. Since there’s no backlight, it relies on reflection from another light source for us to view the contents of the screen. Thus, reading from a e-ink screen is more comfortable since we’re not literally staring into the light all day.

Of course, this is a simplified and by no means comprehensive view of how these displays work.