Traditionally DOOH signage relied on large pixel pitch solutions intended to be seen from afar, like billboards or displays positioned high on buildings. The location implied that viewers would be located at a considerable distance from the screen, which could have pixel layouts as large as 50mm and larger.
However, times change. With displays becoming more affordable customers are concentrating on how fine a pixel pitch they can achieve. The trend for finer pixel solutions also affects the market of outdoor LED displays, and in particular signage. Paving the way are Chinese manufacturers with LAMP having revealed the 3.2mm outdoor display and announced (but not shown) the 2.8mm prototype at ISE 2016.
The outdoor series introduced recently by market majors also feature finer pixels. Daktronics offers 6mm displays within their Gold Series, while NanoLumens has their Outdoor Gallery Series ranging from 4mm to 9mm. The companies build their promotion campaigns due to the product’s enhanced features, such as energy efficiency, the level of brightness, durability, and customer service. Specially developed testing programs, like Barco ‘typhoon testing’, are aimed to prove the reliability of the outdoors solution. As such, smaller pixel layout is seen not as a goal itself but rather a bonus to an enhanced package of options.
Unlike them, second tier manufacturers focus entirely on tighter pixel layouts with the displays having average performing capabilities. Often these are semi-outdoor solutions that feature different level of protection for the display’s front and back sides. Lack of connections’ sealing between power supply unit and LED tile is compensated by cabinet system, which is also a practical solution to speed up installation time.
The tendency for finer pixel layouts in the outdoor segment also increases the product’s actual value as the displays become more functional. The wider scope of usage means they can be used both for indoor and outdoor applications while still maintaining the outdoors-rated level of protection. This makes them suitable for a variety of outdoor installations where viewers are very close to signage, like open air plazas, stadium lounge areas or transportation hubs.
At the same time, closer viewing distance brings more interaction. Smaller pixel layouts enable viewers to be closer to the display so that they can interact with it with more intimacy.
However, are fine-pitch LED displays needed for outdoor installations?
Thanks to the brilliant contrast ratio LED displays are a perfect solution for signage. High level of brightness enables them to deliver the clear and visible message even in brightly lit environments. This is mainly achieved by an ingenious mechanical design that combines black areas between each pixel with louvers between rows of LEDs.
“This maintenance of high contrast, even in high ambient light conditions, relies on the size of the light source (LED) being small compared with the pixel pitch. So, the space between each LED must be large compared with the size of the actual light source in the LED,” - commented Tim Brooksbank, the chairman of Calibre UK, for the SignLink news magazine.
Brooksbank also added: “Very fine-pitch LED displays, sub-2mm, no longer have that characteristic. This means their high ambient light performance suffers, and the usual inherent advantage of direct-view LED displays for signage is lost”.
It is far better to specify the correct display for the job, concludes Brooksbank, as the fine pitch LED displays could produce poor viewing performance. With the advisable viewing distance being at least 1,000 times the distance of the pixel pitch, the 4mm LED screen will require 4m viewing distance. Does it need to be closer? Provided that the display doesn’t imply close customer interaction, like informational or way-finding signage do, most certainly not.
Keeping that in mind, what would you choose for your outdoor installation: a finer pixel pitch displays of average quality or high-end display with larger pixels?