How to choose the right LED screen?
1. Indoor vs Outdoor
2. Type of content displayed on the screen
3. Pixel pitch of the LED screen
4. Brightness and viewing angles
The unit of measurement of the brightness of the LED screen is nit (cd/m2). The higher the value, the higher the brightness of the screen. The brightness for indoor screens should be no more than 1,500 – 2,500 nits. For outdoor screens, the brightness should range from 3,500 nits (for screens without direct exposure to the sun) up to 10,000 nits (when the screen is directly exposed to the sun). Brightness is measured at a normal angle to the screen.
The viewing angle is usually determined by the point where the screen’s brightness is 50% of the maximum. You should notice a change in brightness as you walk along the length of the screen. LED screens have a problem unique to this technology, called “shoulder obstruction”, i.e., when the color change occurs because one LED blocks another LED at critical viewing angles. Viewing angles should include color changes. If a significant color change occurs before the brightness drops to 50%, then that is considered as the viewing angle. The addition of visors between rows of LEDs reduces the illumination of the screen by other light sources, thereby increasing the contrast. This method also reduces the vertical viewing angle, but that is not usually a problem for most LED screen applications.
5. Minimum and maximum viewing distances
Minimum viewing distance can be calculated as pixel pitch x 750-1000. At this distance, a smooth image is observed. Closer inspection of the video will lead to a “decay” of the image into separate pixels. For example, for a LED screen with a pixel pitch of 10mm, the minimum viewing distance is 10mm x 1000 = 10m.
The formula to calculate the maximum viewing distance is generally Screen Height x 20-30. For example, for a LED screen with a height of 4.56 meters, the distance will be 4.56m x 30 = 137m.