Outdoor large screens are used in various public spaces. They are a modern alternative to billboards, posters, and other popular forms of advertising. If they are placed by the roads they impact drivers, they can also be hung on a facade or within sight of passers-by. It is worth to place them in strategic and frequently visited locations.
LED screen displays present content using smaller panels (modules) that are small displays or larger screen elements. In large outdoor screens, the following types of LEDs are used:
- the most common - DIP LED (Eng. Dual In-line Package), where red, green and blue LEDs are used for the formation of a single pixel. The average viewing angle is 110 ° horizontally and 50 ° vertically, the lifetime of 100 000 hours,
- SMD (Eng. Surface Mount Diode) - thanks to its structure the real pixel is obtained - 3 RGB LEDs are enclosed in one capsule, this translates into a higher quality of colour presentation. SMD LEDs are small, larger amount of them can be spread out on the same surface (comparing to the DIP LED). This allows getting a high resolution - expressing the number of pixels that are on the screen. The light generated by SMD LED has a higher and even viewing angle of 110 º x 110 º, which translates into a clear picture, seen under large angles. Average operating time is 100 000 hours. SMD LEDs are characterized by low power consumption.
SMD LED module (left), DIP LED module (right).
RGB LEDs create pixels. These are distributed evenly one from another, and their distance is determined by the pixel pitch distance in millimeters (Eng. pixel pitch, for example, PH10 means LED distance 10mm).
The key parameter distinguishing the type of outdoor large screens from the indoor ones is brightness. Screens for outdoor use must be of a higher brightness than those used in buildings. It is assumed that large screens for outdoor use should have the brightness greater than 5000cd / m². This value reaches up to 12000cd / m², if large screen should clearly present the content under direct sunlight.
Outdoor screens are exposed to external factors. The level of protection against foreign objects such as dust and touch (marked x) and against the harmful effects of water penetration into the device (marked y) defines an IP indicator (International Protection) - IPxy. The level of protection provided by housing is defined in the Polish standard PN-EN 60 529. Frequently used values of the indicator are IP65 (front screen) and IP54 (rear screen) - resistance to water and dust on the outside of buildings, the use of fans, or IP67 - total resistance to ingress of dust and water, lack of mechanical components such as fans.