Selecting a Mounting System

In addition to the LED display itself, it is essential to select a high-quality mounting system, as this factors significantly into the appearance of the display. Ideally, the mount must be able to make up for inconsistencies in the flatness of the wall surface.

“The wall you are attaching to is never that precise, so you have to have a system that is able to mount to that non-flat surface and create a perfectly flat mounting surface for the LED cabinets themselves,” explains Grant Wylie, director of AV product management, Draper Inc., Spiceland, Indiana.

Consequently, the highest-quality mounts offer precision via Z adjustment for the structure, plus X, Y, and Z adjustments for every LED cabinet in the display. This then enables the face of an LED video wall to be perfectly flat all the way across, as minute adjustments can be made at the cabinet level. If the wall is not flat, seams in the LED will show, and the video wall will not appear seamless.

Oftentimes, engineers will mention adjust-ability of the X, Y and Z axis. This is in reference to the placement of the LED cabinet on the mounting structure. Horizontal (left right) adjustment would be the X axis of adjustment, vertical or height adjustment would be the Y axis of adjustment and in and out would be the z-axis of adjustment.

A tolerance of ¹⁄₁₀ the pixel pitch should be maintained while assembling an LED display in order for the image to remain seamless. So if the pixel pitch is 1.2 millimeters from the center of one LED to the next, then the attachment needs to be able to maintain within 0.12 millimeter of tolerance in all axes from one cabinet to the next. This means that there needs to be some means to adjust every LED cabinet independently, in and out, on the mount so that the front face has that precision.

In order to fully develop, manufacture, and install an LED display system, a high level of planning is required. Toward this end, several questions need to be addressed, such as the following:

• Are lifts required for installation?
• Where is the access to the displays?
• How will the display be mounted and installed? On a wall or a floor stand?
• If the wall is built, are architectural drawings available?
• Is a bezel or shroud for the sides of the display required?
• Will the display be recessed into a wall?
• Where will the controllers be located in relation to the display?
• Is it close enough to run CAT, or does the contractor/vendor need to run fiber?
• Is a rack needed for the LED hardware?
• Is a light sensor/brightness sensor required?
• Is remote power control or a power conditioner needed?
• Is there three-phase power within 50 feet of the display location?
• Is power redundancy required?
• If indoors, has the HVAC been sized to accommodate the added BTUs the display will introduce into the environment?

Photo: Matt Oberer

Precise design and alignment are key components of a successful LED installation. Precision is required to preserve the LED’s seamless capabilities, resulting in a finished product that best represents the original design intent.

Curved video walls can be created using flat LED cabinets installed at an angle or faceted to create a display face in the shape of an arc. The main difference between a faceted curve display and a flat display is that each column of LED cabinets is separate from the next and all alignment between them is set and held by the mounting structure.

In contrast, flat LED cabinets have alignment features that help to provide perfect alignment from cabinet to cabinet; however, these alignment features cannot be used when the LED cabinets are placed at an angle next to each other.

Mounting the Display

When attaching an LED mounting structure to a building, the engineered connection should be specific to the material that the mounting structure is attaching to, including wood studs, plywood, cinder block, concrete, and iron.

One application that does require additional work is a metal studded wall. Typically not designed to support an external load, these walls are often used in office retrofits where the existing walls are ripped out and a metal stud floating wall, not secured to the ceiling structure, is built. Consequently, any kind of counterweight would topple the wall over. To prevent this, the wall needs to be reinforced with bracing and plywood on the exterior surface.

If for some reason there are issues with attaching to a wall, mounting to the floor can be more cost-effective than reinforcing the wall. One type of floor mount is a structure that stands on its own, for example, in a hotel lobby. With a floor-mounted structure, the four key elements that must be determined are the floor type, the floor structure that will support the weight, how high the display will be off the floor, and the acceptable depth of the structure.

In attaching an LED display to the ceiling, if it is an existing build, the ceiling structure should be reviewed to make sure it can adequately support the weight. The display will then typically utilize a truss system to attach to the ceiling. Alternatively, it can be suspended with a rigging system. In either case, it is important that the support has backup safety measures in place.

For both wall and standing structures, there are additional considerations if the video wall is curved. A curved wall that is concave provides more depth and immersion, whereas a convex curved wall can wrap around a column. Essentially, a curved wall lets the design fit the space.

Curved walls can be faceted or smooth. A faceted wall uses flat LED cabinets to create a curve with brackets. The faceted curves require extremely precise structure and installation. That said, faceted walls are less expensive, easier to install, and allow for finer pixel pitches compared to custom-manufactured smooth-curved LED displays. However, they are not good for tight radii.

Smooth-curved walls are more aesthetically pleasing and present less drastic color shift from cabinet to cabinet. At the same time, a smooth-curved display does not support the finest pixel pitches, and installation can be more challenging. Smooth-curved LED displays can be either concave or convex.

It is important to point out that all LED cabinets have different mounting hole locations and sizes. Unlike LCD, there are no VESA mounting interface standards for LED mounting hole layout. Consequently, each LED manufacturer and each LED cabinet series has unique cabinet dimensions and mounting bolt-hole placement.

This essentially means that every display is custom manufactured, which means that the mounts must be custom designed for every LED cabinet and its attachment points. Some manufacturers have created mounting systems for specific LED cabinets, and some offer a mount that can scale up and down in size, and support any configurable size and aspect ratio.

As noted, an LED wall mount serves as the interface between a usually inconsistent wall surface and a very flat surface to which the LED cabinets can be attached. With precise X, Y, and Z positioning, the LED display presents a consistent, seamless look.

While a high level of precision is required of any LED video wall structure, this is especially true of NPP displays. The very tight pixel spacings—2.5 millimeters and below—create a detailed and crisp visual, so tight tolerances on the structure are imperative. LED video walls, by nature, are attention-grabbing displays and are frequently used to present some stunning content. Consequently, it is important that the structure not detract from the overall impression. To hide the visible edges of the structure, an attractive trim is required. Some manufacturers offer a black or matte black trim surrounding the LED cabinets to help the mount blend in and appear as minimalized as possible. If the design aesthetic is to achieve an industrial or mechanical look by showing the structure, then it should have an attractive finish.

Another issue is corrosion prevention/protection, even if for aesthetic reasons. Rust spots are very undesirable and could create a false impression that the structure is weak. To prevent this aluminum, galvanized coatings and properly applied paint or powder coat finishes can be used.

Yet another issue is determining if the LED display is front or rear serviceable. With the former, access is much easier, as technicians can go in, remove the LED modules on the front face of the display, access all of the components inside, and service them. In addition, the display can be installed flat to the wall.

While the vast majority of products are front serviceable, several manufacturers still produce rear serviceable systems. Because the LED display needs to project out from the wall to allow for access, this counterbalances the weight. Consequently, architects need to verify that the wall could support the structural load with the display extended out at its farthest distance from the wall.

When installing LED displays, the size of the structural components can potentially pose a challenge to transporting the components to the installation location. For example, displays are frequently 20 to 30 feet wide by 20 to 30 feet tall, however components used to build the display oftentimes need to be able to fit through smaller access points like a service elevator. Consequently, to enable transport of smaller sections, architects should verify that the components can quickly and easily attach together in the final installation location..

As part of the project delivery process, a detailed and outlined process of how the LED cabinets and mounting system will be transported and assembled together is an encouraged best practice. This includes the order of operation for building the system, installing the LED cabinets and the mount, and completing the finish work around the outside of the display. The installation location should be clearly vetted and marked, and during the installation, technicians should make sure that everything is square, level, plumb, and aligned properly. This entire process should be chronologically outlined and precise.

Photo courtesy of Draper Inc.

LED technology can create unique spaces and experiences. It is important that the supporting structure have the same flexibility and modularity to take advantage of LED’s capabilities.