ePaper vs E Ink: what’s the difference?

Q1What is ePaper?

ePaper (electronic paper) is a broad category of display technology that mimics the appearance of ink on paper. Rather than emitting light like an LCD or OLED, ePaper reflects ambient light — so it’s readable in direct sunlight and requires no power to hold a static image. The category includes several underlying technologies, the most common of which is electrophoretic display (EPD).

Q2What is E Ink?

E Ink is a registered trademark of E Ink Corporation, a Taiwan-based company that manufactures electrophoretic display panels. They are the dominant supplier of ePaper panels worldwide — most Kindle e-readers, digital signage, and ESL (electronic shelf label) displays use E Ink Corporation panels under the hood. So while “E Ink” is technically a brand name, it has become widely (if informally) used as a synonym for ePaper.

Q3Are all ePaper displays made by E Ink Corporation?

Not necessarily. While E Ink Corporation supplies the majority of the market, “ePaper” refers to the display category as a whole — not a single manufacturer. If a datasheet or product listing uses the term generically, check the panel manufacturer details to confirm the source. When in doubt, the Crystalfontz product page will list the panel specifications clearly.

Q4How does electrophoretic technology actually work?

The display surface contains millions of tiny microcapsules suspended in a liquid. Each capsule holds negatively charged white particles and positively charged black particles. When a voltage is applied, the particles migrate toward the top or bottom of the capsule, producing a black or white pixel. Because the particles stay in place once moved, the display holds its image with zero power consumption — sometimes called bistable operation.

Q5What are the key advantages of ePaper / E Ink displays?

Ultra-low power — power is only consumed when the image changes. A static display can hold its content indefinitely with no power at all.

Sunlight readability — reflective by nature, so contrast actually improves in bright ambient light, unlike backlit displays.

Wide viewing angle — the reflective surface is visible from nearly any angle without color shift or washout.

Eye comfort — no backlight flicker, and the paper-like surface is easy on the eyes for long reading sessions.

Q6What are the limitations?

Slow refresh rate — updating the image takes 100ms–2 seconds depending on the panel, making ePaper unsuitable for video or fast animation.

Ghosting — partial refresh modes can leave faint remnants of previous images, typically cleared with a full refresh cycle.

Limited color — most panels are black-and-white or 3-color (e.g. black/white/red). Full-color ePaper panels exist but sacrifice refresh speed and contrast.

Requires a frontlight for dark environments — unlike backlit displays, ePaper is not self-illuminating.

Q7Do ePaper displays need to be refreshed periodically?

Yes — and this is one of the most commonly overlooked design considerations. While ePaper’s bistable nature means it can hold a static image indefinitely without power, leaving the same image displayed for extended periods (weeks or months) can cause the particles to partially resist movement, resulting in a “ghost” of the old image persisting after updates. This is sometimes loosely called burn-in, though it differs from the permanent burn-in seen in OLED panels.

To prevent this, most panel manufacturers recommend performing a full refresh cycle at regular intervals — typically at least once every 24 hours for always-on applications. A full refresh briefly cycles the display through black and white states before rendering the new image, resettling the particles and clearing any residual ghosting. Your firmware or display controller should account for this in the update logic, even if the displayed content hasn’t changed.

Q8When should I use ePaper instead of LCD or OLED?

ePaper is the right choice when your application displays infrequently changing information and benefits from low power, outdoor readability, or a paper-like aesthetic. Common use cases include: e-readers, IoT sensor displays, electronic shelf labels, asset tags, industrial HMI panels, and battery-powered field devices. If your application needs fast refresh, video, or full animation — an LCD or OLED is the better fit.

Q9So should I say “ePaper” or “E Ink” in my project documentation?

Use ePaper or EPD (electrophoretic display) when referring to the technology category in general. Use E Ink® only when specifically referring to panels manufactured by E Ink Corporation. Using “E Ink” as a generic term is technically a trademark misuse — and practically, it excludes displays from other manufacturers that behave identically.