NFC - Displays
NFC is usually used to transmit or receive data. For this purpose, at least one communication partner must provide the energy required for data transmission. In most (everyday) applications, it is the NFC-enabled smartphone that supplies the integrated NFC chip together with the antenna with power and enables reading or writing an NFC tag.
Each NFC transmission of an active part (smartphone) generates an electromagnetic field which can be used to supply energy to a passive part (NFC tag). More and more efficient mechanisms and components make it possible to "harvest" the available energy (general energy harvesting), which opens up many other possible applications in addition to passive NFC tags.
Particularly energy-saving displays can be supplied with power via an NFC interface. E-Ink displays, which are typically used in e-book readers, are particularly suitable here. The E-Ink display requires little energy to change the content, but none to display it permanently. The power provided by the NFC can be sufficient to change the display and show the new content permanently. This would not be possible with other, conventional displays (e.g. OLED or LC), as these require energy to maintain the content permanently.
NFC displays in detail
NFC display is the term used to describe E-Ink displays that can receive commands via NFC interface as to what is to be displayed. Particularly economical NFC displays can also do without an additional power source, as the energy is obtained solely from the electromagnetic field.
The E-Ink display consists of very many, very small capsules filled with ink-like pigments that react to certain charges. When the capsules receive a charge, the black pigments collect within the relevant areas on the top surface and thus become visible from the outside. This change of state within the display requires a comparatively low power supply, which can be produced via NFC. An NFC-enabled smartphone can thus be sufficient to provide the required energy. To hold the image it does not need any further energy.
The pixel density of such displays is limited (e.g. 800x400 px at 7.5 inch for the E-display of "Waveshare"), whereby only black / white can be displayed. The E-Ink displays are therefore extremely power-saving, the pigments keep their position after alignment, unlike OLED or LC displays.
Application examples for NFC displays
In the retail sector, E-Ink displays can be applied, e.g. in the form of price tags. A built-in NFC interface makes it possible to update these without contact. The updating of sales prices is thus carried out digitally directly at the point of sale. Also conceivable are applications such as the marking of storage boxes, door plates or advertising on product dividers. This means that new signs do not have to be printed out all the time, or digital displays do not have to be permanently supplied with power. This saves costs and time.
Any displays that do not require regular, time-consuming updates can be equipped with such NFC-based e-ink displays. The energy saving compared to conventional displays is enormous and also makes it possible to update content contactlessly via NFC interface.
Summary and outlook
NFC technology generates a limited electromagnetic field to activate passive communication participants and provide energy for data transmission. In addition to NFC tags, basically all low-energy terminal devices can be operated like the E-Ink displays mentioned here. Such displays require an energy supply to change their appearance. Once this step has been taken, no further energy is required. Since the update rate of such displays is very delayed, they are primarily suitable for permanent displays. Accordingly, E-Ink based NFC displays are typically found on price tags or other symbolic displays.
Erstellt: 2020-04-28 / Aktualisiert: 2020-08-06 2020-04-28 2020-08-06
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