Each control room needs a certain video wall: How to choose the most suitable one?

There are three main categories of solid-state technology used in control room video walls: LCD panels, DLP projection cubes for Led lighting and Led display walls. In this article, Marcos Fernández, Christie's Director for Spain and Portugal, explains the functionalities of each of them and which one best suits each specific application or user, taking into account the characteristics of each environment.

Receive information, Do analysis, Collaborate to maintain normalcy or respond to emergency situations: That's the day-to-day of control room environments. To carry out these tasks, the challenge is how to visualize in real time and efficiently the follow-up tasks, Verification and communication that these tasks require. To establish which technology to support the people who manage and monitor the continuity of work and respond to actual or potential protocol breakdowns, It is critical to determine where and how information will be displayed.

If you need to create an information focal point for a control room team, especially in large formats, that allows operators to view multiple content feeds clearly and simultaneously, Video walls are the mainstream solution.

There are three main categories of solid-state technology used in control room video walls: LCD panels, Led lighting DLP projection cubes (Christie MicroTiles cubes) and Led display walls (Led cubes).

Any of the three technologies can be an excellent choice for use in video wall displays, but to decide which category will be most appropriate for a particular application or user, we will have to look at which features of each solution satisfy the main priorities of the application. Common priorities for control room displays include: The Viewing Angle, brightness, Brightness uniformity, contrast, Self-brightness and color balance, Absence of divisions, Image retention, Occupied space, Initial cost, Total cost of ownership, Ease of assembly, power, service life and compliance with AD standards.

In this column, we're going to discuss which technology categories offer above-average compatibility in terms of their features to help you choose the most appropriate option for each application.

Viewing Angle

Most video wall solutions have been designed to maximize the viewing of information when the user is not directly in front of the screen. However, By distancing ourselves from the viewing angle of the display, we see that brightness and color can be affected at various levels. It is important to consult the product's operating specifications in advance to understand the impact of viewing angles on the interaction between a person and the content.

With cubes, optical screens are commonly used, and each one has its own characteristics. In the case of LCD panels, Visibility may vary depending on who the manufacturer is. In the case of Led video walls there are no clear rules; That said,, There are viewing distances recommended as optimal according to the pixel pitch (Pixel Distance). All solutions offer excellent display characteristics, But when selecting the product, it is important to ensure that the actual features of the selected product meet the design requirements set for the application.

Brightness

The brightness needs of a video wall will vary depending on what the actual application is going to be. An environment with excessive ambient lighting – for example, a space with glass walls—will surely require a high brightness to enhance the overall contrast. Nevertheless, In many control room applications, too much brightness could be detrimental to someone who spends a full workday in front of the display.

If the video wall is very bright, the operator could, with the passage of time, Headaches or vision problems. On the other hand, If it has low brightness, the contrast could be poor, hindering the speed and accuracy necessary to process the information. In typical control room applications, what is indicated and reasonable is a nominal brightness of 250 cd/m². Exceed the 500 cd/m² could lead to excess brightness that we will be forced to reduce and manage.

If you want stable brightness and uniformity across a tiled matrix, Led cubes offer the best performance. Outdoor LED display walls reach brightness peaks of up to 12.000 Nits (1 nt = 1 cd/m²), although in indoor models the levels do not usually exceed 2.000 Nits.

Another advantage of tiled LED video walls is their ability to clearly display content, even in high ambient light conditions. And this is achieved not only by the characteristic high brightness of the Led cubes, but also by the high contrast ratios. The result is an extraordinary perception of the black level that causes high image contrast, even indoors with high levels of ambient lighting.

Brightness Uniformity

When the brightness of each of the individual screens is not uniform, the overall view of the video wall could show an unwanted 'checkerboard' appearance. Most cubes offer a uniformity rate of 95% or more, what is desirable. Instead, on the LCD panel the uniformity is usually not so high.

In addition, since uniformity is not measured right at the bezel level of LCD panels, It is recommended to test and view the solution in advance with the same or similar content to the one we are going to show, thus ensuring that the product meets expectations in terms of uniformity. The average brightness uniformity in Led displays is >97% or higher, depending on the manufacturer's Led chip specification.

Self-brightness and color balance

When multiple displays are combined in a tiled display array or video wall, It is critical that the brightness and color between them are well coupled and remain stable.
In a set made up of several displays, Our eyes are extremely sensitive to color differences, no matter how minimal they are. That's why video wall display products incorporate capabilities aimed at fine-tuning color. However, Over time, both the color and brightness may become out of alignment or change and need to be readjusted.

A great advantage of cubes is that projection technology allows sensors and color monitoring to be incorporated into the design as standard. With this, Constant color and brightness can be tracked, that automatically readjust without human intervention, something that takes place continuously and without the user noticing it.

Led video walls also offer the possibility of achieving a wide colour spectrum, understanding as such the chromatic range and purity that a display is capable of reproducing. On an Led display, The Reds, green and blue emit a much smaller range of wavelengths than a broad-spectrum, white light source, Like a lamp, resulting in the reproduction of much more deeply saturated colours as well as an ever-wider range of reproducible colours.

Contrast

High contrast facilitates easier and faster recognition of the information displayed and reduces harmful effects on eyesight. An essential aspect in the design of a control room is the contrast ratio of the overall system, which must take into account the ambient light inside the room as well as the type of images to be displayed on the video wall. The contrast ratio that is usually required in a system is >100:1.

Display products have their own contrast ratio, which is used to determine the overall contrast ratio of the system. Fortunately, contrast ratios are usually 1500:1 on LCD panels, of 5000:1 in Led and 2100:1 in cubes, in all cases suitable for most control room applications.

Absence of divisions

In a video wall display, it should ideally be completely free of divisions so that in a tiled matrix the viewer does not notice the transitions between the different screen units. The truth is that with the outbound products and technologies currently on sale in the market, it is not a requirement that can be met by the 100%.

In cubes, it is possible to minimize these transitions with distances between screens of only 1 mm. This space of 1 mm is what the materials that make up the screens usually require to expand and contract due to fluctuations in temperature and humidity. On large display walls, against which operators and users are generally placed at a distance of 3 meters away, that space of 1 mm is considered insignificant.

With Led cubes it is feasible to achieve that absence of divisions, because their design allows physical contact between them without this resulting in an increase in the pixel distance between one cube and the next. In addition, the characteristics of the Led cubes environment of a typical array do not allow for accurate appreciation, from a normal viewing distance, The point of junction between cubes.

Image Retention

Chances are, a new video wall system will look shiny, but, Will it be able to maintain that same level of brightness over time?? If performance factors such as color and gloss uniformity, and image quality are not among the top priorities of the app, the use of LCD panels can be an acceptable solution and the best in terms of value for money, especially if the app doesn't require operation 24/7.

However, if what matters is the quality of the image and the maintenance of that quality for five or more years, LED-based DLP displays are the most suitable solution. For example, In many operations centers, it is not only essential to maintain operation at a high level so that operators and regular users work comfortably and safely, It is also important that the video wall display is attractive and impressive for visitors and for customers who come to the facilities.

Footprint and ease of assembly

When there are spatial constraints in the location of the video wall, The thickness of the solution could be a deciding factor. In general, most LCD panels require a space between 10 and 20 cm. depth. If space is at a premium and you also want the benefits of DLP/LED projection, DLP cubes or Led cube-based displays will be the best choice.

The Christie MicroTiles solution offers the advantages of DLP/Led projection cubes with a depth of 10 inches or 250 mm., because it has a screen size of 20 diagonal inches. Led cubes are usually quite thin, often with thicknesses less than 4 inches or 100 mm.

The same, for its minimum depth profile and intelligent design, LCD panels, DLP cubes and Led cubes are also easy to assemble. An interesting aspect in both is the possibility of installing them in a curve or creating a display with any type of size or shape.

Initial cost and total cost of ownership

A big advantage of LCD panels is their low initial cost. On a display surface, the cost of LCD panels can be less than 60% of the initial cost of an equivalent cube-based system. When there are budget constraints, LCD panels may be the most appropriate solution even if their operational life is shorter and some operational sacrifices have to be made.

Fixed costs, and those derived from energy consumption, cooling or maintenance, are also important when deciding on the most suitable solution for the application. In a control room 24/7 or 20/7 Led cubes and tiles can be expected to have a service life of six or more years. These solutions are designed for high reliability, low maintenance and minimal deterioration in performance over time.

All displays consume energy and require cooling, needs that not all technologies solve in the same way. The energy consumption of LED cube video walls is more efficient than that of almost all other display technologies, with efficiency improvements that may exceed 400% depending on which team we make the comparison with.

Another strong point of Led cube video walls is the long life of the Led pixels themselves. Many times the useful life of a light source model is given by the number of hours it takes to drop to half of its initial brightness. Taking into account this parameter, Leds last much longer than lamps, either used as a light source or directly as pixels on a video wall.

Compliance with barrier-free guidelines

If you want to ensure that your display meets the safe space guidelines, accessible and barrier-free of your country and the principles of Universal Design, It is best to opt for a low-impact, thin-thin display.

In Canada and the United States, displays cannot be mounted more than 4 inches or 100 mm of the wall if they aspire to be certified as barrier-free by the CSA (Canadian Standards Association) and the ADA (Americans with Disabilities Act), respectively. LCD panels and LED cubes are solutions that fit well in spaces where the requirements set by CSA must be met, ADA or similar regulations.

By learning how each solution works in relation to the most common control room priorities, you can get a clearer idea of which solution will work best in your own room. Once you have reduced the list of candidates to a minimum, We recommend that you do an in-depth research of the main brands to find the technological solution that best suits your needs.