Choosing the Right System

In addition to the pixel pitch, a number of factors go into specifying the optimal LED display for a given project.

While cost is always a noted consideration, the level of available product support and the extent of the warranty are perhaps equally important to architects and building owners.

Further, there is a wide range in quality, longevity, and performance amongst LED products, so the nature of the installation, for example, a temporary exhibit versus a permanent wall display, will help guide the decision.

Another important factor is the speed at which the product can be assembled. “Time is money, especially on a building site or for installations where disruption to ongoing business operation needs to be kept to a minimum,” states the audiovisual integrator Corporate Initiatives Australia in an LED display white paper for architects and designers. “The best LED products for permanent installation are therefore designed to be easy to put together in a precise manner.”

Maintenance is another issue that must be evaluated. The majority of LED display systems are serviced from the front, which enables easy accessibility. For those that are serviced from the rear, the design will require that additional space be incorporated between the display and the wall for maintenance access, or a complex mount structure is required that allows the display to extend out from the wall for service.

“The ease at which the servicing can be carried out is also a cost factor,” states Corporate Initiatives Australia. “Display systems that are well designed for access make such servicing simpler to accomplish.”

Building teams should also look at the quality of the LED manufacturer’s replacement parts and control system. In cases where displays need to be refreshed with a new module, it is essential for the replacement module to match the remainder of the screen in display characteristics. Otherwise, the result will be an undesired patchwork effect on screen. The goal should be for the LED controller to allow for easy screen calibration so sections both old and new work coherently as one seamless display.

The AV integrator also points out that a typical product procurement process involves developing a series of specifications and drawings, documenting what is required, and putting the whole thing out to bid. However, due to the nature of LED displays as an emerging technology, it is preferable to treat the display as a separate package and make the call on specification much closer to the realization date.

“Nothing is sadder than an LED screen being installed that is effectively already out of date on the day of installation, especially when it happens on a very large scale,” states the white paper.

To better ferret out the LED needs of the project, the following questions should be addressed:

• What is the desired display dimension?
• Where will the display be located, i.e., indoors versus outdoors?
• How bright is the surrounding environment?
• How high off the ground is the bottom of the display?
• What type of content will be displayed, i.e., still images, presentations, video?
• What is the resolution of the native content being sent to the display? Is a scaler required to convert video signals from one display resolution to another?

In determining the size, an indoor LED display is made of interlocking panels. These panels have traditionally been square shaped measuring 500 millimeters. In the past several years, panels measuring roughly 600 millimeters wide by 340 millimeters tall have been introduced, representing a 16:9 aspect ratio. So each increase in size is done by adding modules of these dimensions.

Incidentally, the 600-millimeter by 340-millimeter dimension produces a 27¹⁄₂-inch diagonal panel. By doubling both dimensions, this yields a 55-inch panel, which is the same size as an LCD video wall panel. Consequently, an LCD video wall comprised of 55-inch LCD panels can easily be retrofitted with an LED display using these 27¹⁄₂-inch LED panels.

On the issue of placement, it is important to consider the fact that the LEDs on the face of the modules are very fragile. While the LEDs can be encapsulated with an optically clear coating to improve their ruggedness, this compromises the display’s ability to vent off heat. Further, if an electrical connection comes loose within the encapsulation, the entire module will require replacement, whereas with non-encapsulated LEDs, it is possible to solder and reconnect individual connections within a module.

In any case, it is best practice to locate the display back away from the general public.

Photo courtesy of Draper Inc.

The modular nature of LED panels means a video wall can be in any configuration; it does not have to conform to traditional formats, such as 16:9. It can be 2 high and 10 across, or taller than it is wide.