The new E-Ink display is powered by an NFC signal and does not require a battery

Waveshare has unveiled a 7.5-inch E-Ink display that does not have its own power supply and works only through the received NFC signal. It's perfect for displaying text or images that need to be changed remotely, but not often. For example, on a billboard, an information board in public transport, a screen with a number in a queue at a bank or hospital, etc.

The good thing about e-ink technology is that it doesn't need energy to preserve the color of the pixels. It is enough to pass a single control impulse through the matrix to make specific pixels change their color and form a new image. It will be displayed until the next impulse appears, which will bring both the command and the energy for its implementation.

The source of energy in this case is the NFC wireless communication module itself. The fact is that this technology is very similar to wireless charging - the transmitter of the signal is the generator of the radio frequency field, and the receiver has a small spiral antenna to receive it. This allows enough power to be transferred to activate the E-Ink display. Waveshare says that any device with an NFC module with a power of 1.4 W or more will work for this technology - for example, the Samsung Galaxy S7 Edge from 2016.

NFC's data rate limit is only 424 kbps, as the technology was designed to transmit short data packets like a credit card number or URL. It can take up to 5-10 seconds to transfer an image in 800x400 resolution, taking into account the screen refresh time. Also, the technology does not work on the iPhone, since Apple added the recording function to NFC devices only in the latest version of iOS and the application has not yet been created.