There are three main video wall technologies on the market for control rooms: LCD video wall, rear projection and LED.
How do you know which one you need?
In this article, we'll highlight the pros and cons of each technology to help you make your choice easier.
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So, we have highlighted some key differences between the different technologies in this post.
Several other factors will also influence this decision, but the article will guide you.
Dimensions of the room and walls
The first simple criterion is the size of the control room. For small rooms, the LCD screen is usually the technology with more application options, and the panel thickness is very thin, so the space occupied by the video wall is quite small.
Also, LCDs are great for short viewing distances (providing a great viewing experience even at close range). Good viewing angles ensure that every operator can comfortably see content on the video wall, even when the screen is on the edge of the room. If interactivity is required, an LCD video wall is also a better choice.
But usually in smaller rooms with limited number of operators.
Rear projection cabinets are most comfortable in larger rooms as they require more depth. The operator will have a great optical experience when looking directly at the screen. Therefore, for a medium to large control room, where the operator is located a little further from the wall, a rear-projection box is an ideal choice.
In a slightly larger room, an LED video wall is also a good choice.
They are very thin, so they take up very little space.
But depending on the pixel But depending on the pixel pitch, further viewing distances get the best results. For example, a wall with a 1.2mm pixel pitch is best viewed from a distance of 3 meters.
By the way, the optical properties of LCD TV walls do not limit them to small and medium size walls, they are also suitable for large rooms!
lighting Conditions
In the past, control rooms were often pitch-dark environments. So there was no ambient light source interfering with the video wall content.
However, the increased brightness of video walls has changed this way of thinking, and the brightness produced by LED video walls is also effective in the brightest lighting conditions.Also, this technique is very rarely affected by so-called "specular reflection"
Traditionally, LCD rear projection cubes have lower light output than LEDs. The brightness of the LED light source rear projection module is about 400 nits, while the brightness of the LCD video wall is 500 nits.
These products are suitable for a variety of challenging lighting environments. When designing the layout of room lighting, consider the reflective nature of the display.
Reflection of Light
Besides to the ambient lighting, the position of the light source is also very important.LCD, RPC, and LED video walls differ in light reflection.
First, there are two main types of reflections: Specular and Diffuse (Lambertian).
Specular reflection: Light hits a mirror and is reflected in one direction.
Diffuse reflection is just the opposite, light is reflected evenly in all directions.
Reflections can be an important parameter that can hinder the operator's viewing experience. It needs proper attention.
The reflection of the LCD screen is close to that of a specular reflection, requiring a clever method to locate the position of the light fixture.
In most cases, this isn't a huge problem: just make sure the lights aren't facing the video wall, and most disturbances won't happen.
LED video walls are just the opposite, acting like a diffuse diffuser, and for this type of video wall, the rule is that the darker the room, the better the contrast ratio.
The amount of reflected light from the RPC rear projection is limited, making it a good solution for rooms with fixed light locations and windows. In these rooms, the lighting conditions cannot be adjusted to the video wall.
What to Display
The physical characteristics of the control room have been discussed above, but the content on the video wall is also very important.
In this area, the inter-screen gap or bezel width is an important parameter. They form black lines around each display, making the video wall look like a grid.
In utilities and process control, often a single (SCADA) application is spread across the entire video wall.
This means that black lines will traverse the content, preventing a seamless viewing experience.If the background is black, the lines will not be visible, but the content will still be interrupted.
Of the three different technologies, LED is the only one that is completely seamless, ensuring an uncut viewing experience.
The LCD video wall has the most obvious interruption between screens, and is commonly used in monitoring centers.However, LCD screens with relatively small screen pitches on the market are almost seamless, which brings more possibilities to LCD panels.
The rear projection cube has a small screen gap that is barely noticeable, making it suitable for any application. But the price is always unaffordable, Barco is a pioneer in the field of RPC.
In Conclusion
There is no such thing as "the best video wall technology".
It all depends on the use case, what's on the wall, and the infrastructure to determine which is right for your needs.
1 LCD splicing screen:
Suitable for small to medium size walls
Does not take up much space
Excellent image quality for close viewing
Good viewing angle
Great for video-centric content
2 RPC rear projection splicing cabinet:
Suitable for medium to large sized walls
No aging effect, suitable for SCADA static content
Strong stability, 24-hour non-stop operation of the control center
Upgradable, one-time investment for long-term use
3 LED screen:
Suitable for medium to large sized walls
Very thin and takes up little space
Very bright, can be used in brighter ambient lighting conditions
Perfect seamless, unlimited display ratio
