Author: Jon Litt, Senior Manager, Networked Display Solutions, Christie
The reality of control room environments is receiving information, analyzing it and collaborating to either maintain the current state or respond to an emerging event or current operational conditions. Where this information should be displayed and effectively monitoring it is an important element to any critical viewing application. Large format video wall technology is a solution that many control rooms utilize for this purpose and deciding on the type of technology that suits your needs can be an overwhelming exercise.
There are three primary categories of solid-state technology used for control room video walls: LCD panels, LED-lit DLP® projection cubes (cubes) and direct view LED display walls (LED tiles). While each of these technologies is a very good choice, it is important to determine your priorities in order to ensure the best fit.
There are many priorities that should be considered when choosing video wall technology but the three most common topics that I discuss with clients are:
· Viewing angle
Most display solutions are designed to maximize the view of information when the user is not directly in front of the display however brightness and color may be affected to a degree as the viewer moves further off-angle. It’s important to consider this and verify the products specifications in advance to ensure operators have the best possible interaction with the video wall. When referencing LED video walls, there are recommended optimal viewing distances depending on the pixel pitch. For cubes, optical screens are typically used and each type has its own unique characteristics and for LCD panels, visibility can vary based on the manufacturer. All solutions can provide very good viewing characteristics, but during product selection it is important to ensure the actual characteristics for a selected product meets the design requirements set for the application.
As with viewing angle, brightness requirements for video wall applications vary depending on the application. Higher brightness may be necessary to improve overall contrast in environments where ambient light is very high – such as rooms with a lot of windows. However, for many control room applications, too bright can be considered a downside if people are working in front of the display wall for a full working shift. If the wall is very bright, those people may suffer from headaches or eye strain over time. On the other hand, if the wall is not bright enough, contrast will likely be too low, making it difficult to quickly and accurately discern information as required. Ideally there should be very little if any difference between the brightness of the computer monitors directly in front of the operator and the video wall. As the operator’s eyes drift from their own monitors to the video wall, their pupil movement would then be minimized. This in itself will reduce operator fatigue and thus enhance situational awareness.
If you’re looking for brightness and uniformity across a tiled array, LED tiles offer the best performance for these attributes. Another benefit of direct view LED video walls is their ability to display content clearly even in high ambient light environments.
Ideally, a video wall display should be completely seamless so that viewers do not notice a transition from one display screen to the next in a tiled array. In reality, this is not always 100% achievable with emissive display products and technologies currently on the market. LCD panels have the widest transitions of the three primary display technologies. Modern day manufacturing processes have enabled the transitions to be reduced to as small as 1.7mm and then the progress up to 13mm.
Cubes have the ability to minimize this transition by offering a gap between screens of slightly less than 1mm. This 1mm space is typically required to allow for expansion/contraction of the screen materials during temperature or humidity fluctuations. For large display walls where operators and users are typically at 3 meters (10 feet) away, 1mm is considered negligible. Direct view LED tiles achieve seamlessness and are designed in such a way that they touch each other without increasing the distance between the pixels from one tile to the next. Moreover, the nature of the area surrounding direct view LEDs in a typical tiled array makes it difficult to see where the tiles join from a normal viewing distance essentially creating a seamless image.
Based on the priorities discussed, you may have a better understanding of which video wall technology would be the best fit for your control room, or at the very least you may have narrowed your search options and are now ready to start doing an in-depth analysis of the brands for your solution of choice.
Jon W. Litt, CTS
Senior Manager, Networked Display Solutions, Americas
Jon joined Christie as a control room specialist in 2014 and now serves as the Senior Manager for the Networked Display Solutions team focused on control room, visualization, simulation and video wall applications. Jon has worked in the field of electronics for over 25 years, focusing mainly on working in systems integration consulting customers in a wide variety of AV technology applications. From early in his career working in the field of electronics for the US Navy, to owning his own integration firm followed by a number of years working for large systems integration firms, Jon has been committed to helping his clients make the right choices for their visualization needs. Jon is looked upon as a thought leader in the industry, having led many educational seminars and sessions while also actively sharing industry insights on social media and throughout many highly regarded industry publications.