Each control room requires a specific video wall: how to choose the most suitable one?

There are three main categories of solid-state technology used in control room video walls.: paneles LCD, Led lighting DLP projection cubes and Led display walls. In this article, Marcos Fernandez, 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 normality or respond to emergency situations: that is the day to day life of control room environments. To carry out these tasks, the challenge is how to visualize the monitoring tasks in real time and efficiently., verification and communication that these tasks require. To establish what technology to support the people who manage and monitor the continuity of work and respond to real or potential breaches of the protocol, It is essential to determine where and how the information will be displayed.

If what is needed is to create a focal point of information for a control room team, especially in large formats, allowing operators to clearly and simultaneously view multiple content feeds, video walls are the widespread solution.

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

Any of the three technologies can be an excellent option for use in video wall displays., but to decide which category will be most appropriate for a specific application or user, We will have to look at which characteristics of each solution satisfy the main priorities of the application. Typical priorities for control room displays include: the viewing angle, glow, gloss uniformity, contrast, auto brightness and color balance, absence of divisions, image retention, occupied space, initial cost, total cost of ownership, ease of assembly, power, shelf life and compliance with AD standards.

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

Viewing angle

Most video wall solutions have been designed to maximize 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 the 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, It is common to use optical screens, and each one has its own characteristics. In the case of LCD panels, visibility may vary depending on the manufacturer. In the case of Led video walls there are no clear rules; having said this, There are viewing distances recommended as optimal based on pixel pitch. (pixel distance). All solutions offer excellent display features, but when selecting the product it is important to ensure that the actual characteristics of the selected product meet the design requirements set for the application.

Glow

The brightness needs of a video wall will vary depending on what the actual application will be.. An environment with excessive ambient lighting—for example, a space with glass walls—will surely require a high brightness to improve 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, suffer headaches or vision problems. On the other hand, if it is low brightness the contrast could be poor, hindering the speed and accuracy necessary to process information. In typical control room applications, what is indicated and reasonable is a nominal brightness of 250 cd/m². Overcome the 500 cd/m² could lead to excess brightness that we will be forced to reduce and manage.

If what we want is stable brightness and uniformity throughout a mosaic matrix, Led cubes are the ones that offer the best performance. Led display walls located outdoors 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 mosaic LED video walls is their ability to clearly display content., even in high ambient light conditions. And this is achieved not only by the high brightness characteristic of the LED cubes., but also because of the high contrast ratios. The result is extraordinary black level perception resulting in high image contrast., even indoors with high levels of ambient lighting.

Gloss 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 as high.

Besides, since in LCD panels the uniformity is not measured right at the level of the bezel, It is recommended to do a test and view in advance the solution with content equal or similar to what 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% the superior, depending on the manufacturer's Led chip specification.

Auto Brightness and Color Balance

When multiple displays are combined in a mosaic display matrix or video wall, It is essential 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, however minimal they may be. That's why video wall display products incorporate capabilities aimed at accurately adjusting color.. However, Over time, both color and brightness may become unbalanced or change and require readjustment..

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

Led video walls also offer the possibility of achieving a wide color spectrum, understood as the chromatic range and purity that a display is capable of reproducing.. On an LED display, the reds, Greens and blues emit a much narrower range of wavelengths than a white, broad-spectrum light source., like a lamp, resulting in the reproduction of much more deeply saturated colors as well as an increasingly wide range of reproducible colors.

Contrast

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

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

Absence of divisions

In a video wall display, the ideal is for it to be completely free of divisions so that in a mosaic matrix the viewer does not notice the transitions between the different display units.. The truth is that with the emissive products and technologies currently on sale in the market, it is not a requirement that can be met at 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, from which operators and users are generally located within 3 meters away, that space of 1 mm is considered negligible.

With LED cubes it is possible to achieve this absence of divisions, since its design allows physical contact between them without resulting in an increase in the pixel distance between one cube and the next. Besides, The characteristics of the environment of the Led cubes of a typical matrix do not allow us to accurately appreciate, from a normal viewing distance, the union point between cubes.

Image retention

Most likely, a new video wall system will look brilliant to us, 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 application's top priorities, resorting to LCD panels can be an acceptable solution and the best in terms of quality-price ratio, especially if the application does not require operation 24/7.

However, if what matters is image quality and maintaining 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 clients who come to the facilities..

Occupied space and ease of assembly

When there are spatial limitations 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 of between 10 y 20 cm. deep. If space is limited and you also want the advantages of DLP/LED projection, DLP cubes or displays based on LED cubes will be the best option.

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

Also, for its minimal depth profile and intelligent design, LCD panels, DLP cubes and Led cubes are also easy to mount. An interesting aspect of 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 great advantage of LCD panels is their low initial cost. In 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 although their operational useful life is shorter and some operational sacrifices must be made..

Fixed costs, such as those derived from energy consumption, cooling or maintenance, They are also important when deciding the most suitable solution for the application.. In a control room 24/7 o 20/7 A useful life of six or more years can be expected for LED cubes and mosaics.. These solutions are designed to offer great 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 decrease to half its initial brightness.. Taking into account that 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 make sure your display meets safe space guidelines, accessible and barrier-free from 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 established 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 investigation of the main brands to find the technological solution that best suits your needs..

Marcos Fernandez

Director of Christie for Spain and Portugal