The ‘finest’ LED display to date, launched in September 2016, delivers a pixel pitch of just 0.9 mm (0.035 in.).
Photo courtesy Leyard
Classifying signs
The main purpose of all signs and displays is to communicate and convey information, such that the receiver may make cognitive decisions based on the information provided. They are similar to but distinct from labels, which convey information about a particular product.
Signs may also be classified according to the following functions:
- Information—Many signs display information about services and facilities, such as directory listings or instructions.
- Direction—Wayfinding systems, comprising such elements as directional arrows and sign posts, direct people to the various service locations, facilities, functional spaces and key areas.
- Identification—Upon arrival, this type of sign indicates immediately available services and facilities. Examples include room names and numbers, restroom signs, as well as various floor designations.
- Safety and Regulatory—Warning signs, traffic signs and exit signs are all examples of signs that provide warnings or safety instructions. Others convey specific rules and regulations.
Illumination options
LEDs offer a vast array of options for illuminating signs. The latest high-brightness LEDs (HB-LEDs) are low-voltage, low-heat and operate with low running costs, allowing signs to be both brilliantly bright and energy-efficient. Further, they provide increased longevity compared to traditional forms of lighting, reducing the maintenance costs that are associated with signs.
LEDs can be used for rear, halo or front lighting of metallic or acrylic channel letters, with many subtle, esthetically pleasing effects possible. They can also edge-light acrylic panels, which can be used independently as light sheets or collectively to form light walls. Another option is to integrate LEDs into aluminum frames to produce ultra-thin lightboxes.
Indicating destinations
The installation of LED-based signs in or on public transportation vehicles, by way of example, remains a stable market. These include destination signs or indicators mounted on the front, side or back of
a bus, streetcar/tram or light-rail transit (LRT) vehicle, which display the route number, name and/or destination.
Today’s destination indicator signs include a mix of flip-disc, liquid crystal display (LCD) and LED panels that can be animated to display text and, in some cases, colours. They can indicate a potentially unlimited number of routes, so long as they are programmed to do so via the vehicle’s on-board computer. Some of these signs also change as the vehicle moves along its route with the help of the Global Positioning System (GPS) and a centralized vehicle-tracking system.
In the U.S., the Americans with Disabilities Act specifies certain criteria for transit vehicles’ destination signs, including maximum and minimum character height-to-width ratios and contrast levels, to ensure the signs are sufficiently readable to visually impaired persons. These criteria have informed the designs of LED-based transit signs in other countries, too.
LED-based digital signage
Digital signage uses content management system (CMS) software and media distribution technology—whether based on a local personal computer (PC) or server or hosted by a regional or national provider—to display information on a dynamic screen, which may be LED-based.
This application category goes beyond the aforementioned LED-based destination signs on public transit vehicles to include large digital billboards along roadways, arrival and departure signs at airports and railway stations, time-and-temperature signs, open/closed signs and super-large scoreboards at sports stadiums, among other possibilities.
While many ongoing evaluations of LEDs have focused on their potential to displace traditional lighting in general architectural illumination applications in the future, there is a need to overcome some misconceptions about their true value proposition. Many implementations of LEDs are indeed intended to replace existing light fixtures, but others are using LEDs as an entirely new model for ‘digital light,’ exploiting the capability to control LEDs dynamically so as to display information. They have already become a mainstay technology for the digital signage sector.
Dynamic displays in high-traffic areas are changing the face of public spaces and there are still further possibilities for digital signage everywhere. LED arrays can be used for informational messaging, advertising, entertainment and architectural ambience, transforming the experiences of shopping, working and socializing.
