What is a video wall?

A video wall (also known as display wall) is a large visualization surface consisting of multiple displays. Originally, they consisted of multiple televisions or monitors that were put closely together. The objective was to make it seem as one large display surface. The problem however was the large frame (or bezel) that surrounded the useful display surface of each television. This completely tore down the effect of a single canvas and ruined the visual performance. Therefore, new technologies were introduced to minimize the ‘dead pixel space’ between the different displays. Today’s display wall solutions are generally using tiled LCD panels, rear-projection cubes, or direct LED tiles.

These display walls are available in a wide range of sizes, typically with a screen diameter between 46” and 80”. The choice of the screen size depends on the typical content and the viewing distance. If watched from up close, the pixel density should be high enough to not see the individual pixels. The resolution is subject to the wall size. For example, a 4K video wall requires 4 Full HD screens in a 2 x 2 setup.

Typical application areas include control rooms, meeting rooms, digital signage and other demanding environments.

Although these different technologies have very distinct merits, answering specific needs of users, they have a number of things in common. They all:

• Need a video wall controller to get content on the screens
• Are very flexible regarding size (number of individual displays)
• Need a calibration mechanism to ensure that all individual tiles have the same brightness and color settings
• Require a minimal inter-tile gap (or ultra narrow bezel) to counter the ‘raster effect’

LCD video walls #

An LCD video wall consists of multiple specifically designed LCD displays. Contrary to the panels used in television sets, these LCD displays have a very narrow bezel. This minimizes the gap between the panels, making it look like one big canvas. Over the years, this gap has gradually decreased. Today, Barco UniSee has the smallest gap in the industry.

LCD video walls are designed for long term and intensive use, often playing in a 24/7 mode — which means they are rarely switched off. Specific measures to prevent burn-in effects are applied to allow them to play for many years, in optimal conditions.

The traditional benefits of LCD video wall solutions include the high brightness, good image quality, and relatively low cost. Also the limited real estate space needed is a plus. The disadvantages are the risk for burn-in and the lower lifetime. Recent models however have successfully reduced these drawbacks.

Typical markets for LCD display walls include meeting and crisis rooms, lobbies, and experience centers. You can also find them in the control rooms of traffic and security centers.

LED video walls #

Direct-view LED technology is used to create the most impressive video walls. They are very bright and are often not only used to inform or to collaborate, but also to wow audiences. For example in retail & advertisement settings, during spectacles or live performances, LED video walls are used. Due to recent price-drops for LED video walls, they have become in reach of most corporations, to use in control rooms or corporate lobbies. The LED display tiles consist of many individual color LEDs. The pixel pitch can be quite large when they are watched from afar (for live performances for example), or very small (for control rooms or lobbies.

The high brightness, absence of inter-tile gaps and impressive colors are the main benefits of direct-view LED technology. Also the limited depth and weight can be important in certain settings.

Rear-projection video walls #

Using projection instead of LCD or direct-view LED technology, rear-projection video walls target different applications. They are mainly used in control rooms that operate in a 24/7 mode. Utilities providers, for example, generally rely on rear-projection technology to monitor their network.

A rear-projection video wall consists of multiple cubes, which feature a projector and a screen. The projectors are positioned upwards. A mirror under a 45° angle then reflects the image and casts it onto the projection screen. In this way, the required depth is cut dramatically. For example, some series only requires a depth of 60 cm/23.6”. This advanced video wall can also be serviced from the front, so there is no need for a rear maintenance area. The benefits of this technology include the very high lifetime, the absence of burn-in effects, and the narrow gap between cubes.