While most businesses that decide to use an outdoor screen, whether for outdoor digital signage, information or entertainment, realise the need to protect the screen from the elements, all too often, one aspect of outdoor screen use gets forgotten—the sun.
The sun can cause several problems with an outdoor screen, which lead to viewing problems. And any screen where the audience can’t see the content is not accomplishing the intended requirements. Coping with the problems caused by the sun is not easy, and requires different methods depending on the problems caused:
Screen glare is something that may be familiar to most people. If you’ve ever had to shut the curtains whist trying to watch TV at home during the day, then the reason was probably due to screen glare. Screen glare is when the sun is reflected off the surface of the screen face and can make it impossible to see the content.
The simples cure for screen glare is to make sure the screen is not facing the direct path of the sun; however, this is not always possible especially for south facing screens (or north facing in the southern hemisphere).
Using an anti-reflective glass is one of the only solutions to prevent screen glare, but this has the drawback of tinting and dimming the screen, so a screen of higher brightness is needed.
High brightness screens are a prerequisite for outdoor use. Because of the sun’s brightness and the problems caused by screen glare, standard indoor screens often struggle when it comes to readability.
Screen brightness is measured in candelas (sometimes called nits) and an indoor screen typically has a candela value of around 500. For outdoor digital signage, to ensure the screen can cope against the brightness levels of the sun, candela values of at least 1,200 are needed—the higher the better.
Another problem caused by the sun, especially when the screen faces the sun’s path, is overheating of the screen face. Continuous sunlight bearing down on a screen may result in the hotspots developing, which in turn can lead to permanent burn marks appearing on the screen. While tints and anti-reflective glass can alleviate this problem to some degree, often the only solution is to provide a curtain of cool air across the screen face, transferring any heat build-up away.