Receive information, analyze and collaborate to maintain status quo or respond to emergent situations – this is the reality of control room environments. The challenge lies in effectively visualizing real-time intelligence for efficient monitoring, awareness and communication. Where and how information is displayed are critical questions in determining what technology will support those who are managing and monitoring operational continuity, and responding to actual or impending breaches in protocol. When you need to create a focal point of information for a control room team, particularly in a large format that allows operators to view multiple feeds of content clearly and simultaneously, video walls are the prevalent solution.
There are three primary categories of solid-state technology used for control room video walls: LCD panels, LED-lit projection cubes and LED display walls (LED tiles).
While each technology is an excellent choice for use in video wall displays, determining which category is most appropriate for the application or user depends on what solution attributes are top priorities for the application. Some of the most common priorities for control room displays include:
- Viewing angle
- Brightness uniformity
- Auto-brightness and color balance
- Image retention
- Initial cost
- Total cost of ownership
- Ease of deployment
- ADA compliance
Most video wall solutions are designed to maximize the view of information when the user is not directly in front of the display screen. However, as you move further off-angle from the display, brightness and color may be affected to varying degrees. It is important to verify the product performance specifications in advance to understand how viewing angles will impact a person’s interaction with the content.
For cubes, optical screens are typically used and each type has its own unique characteristics. For LCD panels, visibility can vary based on the LCD panel manufacturer. When referencing LED video walls, there are no hard and fast rules; nevertheless, there are recommended optimal viewing distances depending on the pixel pitch. 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.
Brightness requirements for video wall applications vary depending on the actual application. Higher brightness may be necessary to improve overall contrast in environments where ambient light is very high – such as rooms with walls 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. For typical control room applications, a nominal brightness of 250 cd/m2 is quite adequate and reasonable. Above 500 cd/m2 may be too bright whereby brightness may need to be lowered and managed.
If you’re looking for brightness and uniformity across a tiled array, LED tiles offer the best performance for these attributes. Outdoor LED display walls can achieve peak brightness of up to 12,000 nits (1 nt = 1 cd/m2 ), although levels for indoor models are typically less than 2,000 nits. Another benefit of LED-tiled video walls is their ability to display content clearly even in high ambient light environments. This is a consequence not only of the high-brightness typical of LED tiles but of high contrast ratios. The result is an outstanding perceived level of black, resulting in a high contrast image even in elevated levels of indoor ambient light.
If brightness is not uniform within each screen, the overall video wall may exhibit a “checkerboard” appearance which is undesirable. Most cubes offer uniformity of 95% or better which is desirable, while LCD panel uniformity is not typically as high. Additionally, because uniformity is not measured right to the edge of the bezel on LCD panels, it is recommended to test and view the solution in advance with content that is the same as/similar to what will be displayed to ensure that the uniformity meets expectations. Brightness uniformity for LED displays is typically >97% or better depending on the manufacturer’s specification for its LED chip.
Auto-brightness and color balance
When multiple displays are used together in a tiled display array or video wall, it is critical that brightness and color from display to display are well matched and remain that way over time. Our eyes are very sensitive to even subtle differences in color across multiple displays; therefore, video wall display products include capabilities to finely adjust the color for best matching performance. However, over time, color or brightness may slightly change or drift, requiring readjustment. A major benefit of cubes and MicroTiles is that projection technology allows color sensors and monitoring to be embedded within the design so that color and brightness can be constantly monitored and automatically re-adjusted without human
intervention. This occurs continuously and is transparent to the user.
LED video walls also offer a large achievable color gamut, which is the range and purity of the colors a display can reproduce. The red, green and blue LEDs used in LED display walls all emit a much narrower range of wavelengths than a broad-spectrum, white-light source like a lamp. This allows more deeply saturated colors to be reproduced, as well as increasing the range of reproducible colors.
Higher contrast enables easier and faster recognition of the information displayed and reduces eye strain. For control room design, the overall system contrast ratio is critical. This takes into account ambient lighting within the room as well as the imaging within the video wall display. Typically, a system contrast ratio of >100:1 is what is required.
Display products themselves have their own contrast ratio which is used to help determine the overall system contrast ratio. Fortunately, the contrast ratios are typically 1500:1 for LCD panels, 5000:1 for LED video walls, and 2100:1 for cubes, which are acceptable in most control room applications.
Ideally, a video wall display should be completely seamless so that viewers do not notice a transition from one display screen unit to the next in a tiled array. In reality, this is not 100% achievable with emissive display products and technologies currently on the market.
Cubes have the ability to minimize this transition by offering a gap between screens of only 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.
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 LEDs in a typical tiled array makes it difficult to see where the tiles join from a normal viewing distance.
When a video wall system is new, it can look brilliant, but will it maintain that same level of performance over time? If image performance factors such as color uniformity, brightness uniformity and imaging quality are not the highest priorities for the application, then the use of LCD panels may be acceptable and the most cost-effective solution – especially if the application does not require 24/7 operation. However, if quality of the image is important at all times for 5+ years, then DLP/LED-based displays might be the best choice. For instance, in many operation centers, it is not only critical that a high level of performance is maintained for the benefit of the normal operators and users, but it is also important that visitors and customers who tour the operations see an engaging and impressive video wall display.
Footprint and ease of deployment
If space is limited at the location of the video wall, then the physical depth of the solution may be a key deciding factor. Generally, most LCD panels can be installed requiring only 4-8″ of space front to back. If space is at a premium, but the benefits of DLP/LED projection are in demand, then MicroTiles or LED display tiles may be the best option. MicroTiles offer the benefits of DLP/LED projection cubes with a 10″ depth due to their 20″ diagonal screen size. LED tiles are typically quite thin, often with a depth of less than 4″ or 10mm.
As well, because of their minimal profile depth and smart design, LCD panels, MicroTiles and LED tiles also offer ease of deployment. One intriguing possibility with both Christie MicroTiles and LED tiles is the ability to mount them along a curve, or create any size or shape of display.
Initial cost and total cost of ownership
A big benefit of LCD panels is their low initial price. For a given display surface area, LCD panels can be less than 60% of the initial cost of an equivalent cube-based system.
Although operational lifetime is lower and there are other performance compromises, LCD panels could be the most appropriate solution for the application at hand when budgets are tight.
Considering the ongoing operational costs such as power consumption, HVAC and maintenance is also important in determining the right solution for your application. In a 24/7 or 20/7 control room you can expect cubes and LED tiles to have a useful life of approximately six years or more. These solutions are designed for high reliability, very low maintenance and minimal performance degradation over time.
All displays consume power and require cooling, but not all display technologies are the same in this regard. LED tile video walls consume energy more efficiently than most other display technologies. The improvement in efficiency can be as high 400% or more, depending on which displays are being compared.
Another strength of LED tile video walls is the long life of the LED pixels themselves. The useful lifetime of a display’s light source is often defined as the number of hours to reach half of the initial brightness. By this measure, LEDs typically last much longer than lamps, whether used only as a light source or employed directly as pixels in an LED video wall.
Based on the performance of each solution in relation to the most common control room priorities, you may have a clearer understanding of which solution will work best for your control room. Once you’ve narrowed down which technology makes the most sense, we recommend doing in-depth research on the top brands for your solution of choice.
Connect with a consultant
If you have additional questions, or if you need some help in selecting brands to explore, contact us. We can connect you with a network of experts who will be happy to help you work through the final steps of your procurement process.
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