Digital out-of-home advertising was a growing sector of advertising until the COVID-19 pandemic hit. Emarketer predicted out-of-home advertising would grow by 3.3% in 2020, but revised that estimate to a 4.6% decline following the pandemic outbreak and subsequent quarantine orders. Despite the decline, they still predict $8.25 billion will be spent on OOH (out-of-home) with 33% ($2.72 billion) of that figure representing DOOH (digital-out-of-home) .

Even though the pandemic pumped the brakes on this growing sector, DOOH advertising should continue to grow as a viable medium for advertisers desiring to push their message beyond desktop, mobile and connected TV. Innovation around how DOOH advertising creatives are displayed  is a key factor that affects growth. The small displays churning out video ads at gas station pumps may be the most innovative thing to happen to DOOH in recent memory, but electronic paper displays might be the next innovation to rock this niche pocket of digital advertising.

Electronic paper displays are not a new technology, but their application in large format digital signage is presenting itself as a viable method of advertising. Electronic paper is the same display technology found in an Amazon Kindle. The term "electronic paper" or "ePaper" is a generic term to represent this technology but the actual panels are manufactured by a company called E Ink. Positive and negative charges are applied inside the panels to rearrange actual pigments, which is why ePaper looks and reads just like paper.

There are inherent advantages to ePaper over traditional LCD or LED display panels.

Weatherproof

The newest Kindle, the Oasis, is waterproof and some commercial signage applications can maintain an IP65 waterproof rating.

Size

These panels are often razor thin. OLED panels are the closest match when comparing to traditional displays but OLED still requires components to be housed inside the panel creating a bulge in the display or requiring a separate unit like LG's Wallpaper TV.

Low Power

Electronic paper displays consume a minuscule amount of power relative to other displays. Visionect, an E Ink partner, sells a 32 inch electronic paper display & development kit that they claim is 99% more power efficient than a traditional LED or LCD display. The low power needs of ePaper enables solar or battery powered implementation, allowing placement that would be unfeasible with traditional displays.

Readability

The most compelling advantage of an ePaper display is the superb readability. Kindle owners have known this for years but ePaper offers a completely glare free experience in full sunlight.

These features open up the door for some interesting and unique use cases. One example of a company pushing the limits of DOOH advertising with ePaper is this application from German company RoadAds Interactive, in partnership with Visionect.

These companies install a 3 ft x 5 ft electronic paper display on semi-trucks equipped with cell + wi-fi connectivity and GPS. These displays are capable of displaying continually refreshed ads updated remotely from the RoadAds online platform. The GPS also enables location targeting, where an ad can adapt to its current location — like changing languages as a truck travels across countries in Europe.

This electronic paper digital signage application by RoadAds takes full advantage of all four killer features outlined above.

  1. Weatherproof - The displays need to be weatherproof so they can stand up to the harsh conditions found on the open road.
  2. Size - The size of the displays allows them to be easily mountable to the truck.
  3. Low Power - The low power consumption ensures that the display will not drain the truck's battery
  4. Readability - The readability of the displays in full sunlight makes each ad highly visible and they comply with European legislation on motor vehicle lighting devices.

The low power demands of electronic paper displays could allow the placement of a display at any location with access to ample sunlight. The company Papercast sells a display and content management platform for publishing real-time bus schedule information that can be coupled with a solar panel to create a fully self-sustained display solution. This could allow for displaying advertisements where access to or cost of power would present complications.

It's not all rainbows and butterflies when it comes to ePaper. There are some obvious drawbacks in the technology, such as: few ready for market solutions, lack of color, slow refresh rate and poor nighttime display. Most displays are monochromatic, take a few seconds to refresh, and need a harsh backlight to display content at night. But some of these problems are being addressed.

The previously mentioned Visionect Place & Play 32″ Development Kit offers the most "ready for market" solution for potential advertising applications. At $6,000 this kit allows developers to "use standard web technologies to design interactive apps or use existing applications for development of your custom digital sign". The price tag is a $3,400 premium over the non-commerical version of the same display that "does not allow for the creation of a commercial product to generate revenue", which means no selling of advertising inventory.

The other alternative is to build a custom solution by purchasing the display direct from E Ink. The electronic paper manufacturer offers a 42" monochromatic display for $2,300. The downside is that this is just the display and would require a custom hardware and software solution to implement any type of advertising application.

Both of the solutions above could only offer monochromatic display of advertising creatives. This severely restricts a brand's capability to capture a consumer's attention with vibrancy and creativity. Although, E Ink has already developed color technology for their displays, but it is unclear how much they will cost in large digital signage formats and what that premium will be relative to existing ePaper displays.

As for the refresh rate issue, Waveshare looks to have a display that can refresh in semi real-time via HDMI. This could solve the "screen flash" required on ePaper displays to change the displayed image and enable simple video applications.

Even with its drawbacks, the benefits of ePaper cannot be ignored for potential digital out-of-home advertising applications. Through cell and wi-fi connectivity, these displays could hook into a programmatic advertising platform, soliciting real-time bids from potential advertisers looking to push their message out on the sidewalk, bus stop, highway or anywhere with access to sunlight. The recent pandemic may have pumped the brakes on DOOH for now, but don't be surprised to see this emerging technology start to pop up in large cities in the near future.