Ask the Board – January 27, 2020 | MIKE WHITE


“Projections vs. display technology. When is one chosen over the other?”

What a difference laser and LED light engines have made. Until the last few years, when laser and LED light engine projectors were available at a cost-effective price, the consideration to use traditional bulb-based projectors was very seldom the right choice. While projectors have always provided, and will likely continue to provide, the most cost-effective area coverage, the digital signage duty cycle (often 18 hours or 24 hours a day) make the traditional bulb projector an economical and logistically tough choice.

Traditional bulb projectors with 3,000-hour bulb life would need replacement every three to four months, seldom lasting the suggested bulb life because of heat fatigue. Because bulb projectors require filter changes as well, the need for ongoing service becomes a serious logistical nightmare. However, things have really changed in the last few years and now often provide a better solution than video walls or even direct-emit LED walls.

With today’s laser and LED light engines, we can now focus on the advantages that the projector brings to us in size and flexibility and worry little about the projector’s ability to stand the test of time.

So which one of the technologies should you choose?  Well, the question is much like the other considerations when designing your entire digital signage project. It comes down to knowing what questions to ask and knowing your options. The hardware, which includes the display technology, is still the easiest part of the successful digital signage design, but first you also need to…

  • Clearly identifying the reasons that you are willing to invest in digital signage (i.e., ROI – Return on Investment, ROO – Return on Objective, ROA – Return on Attention)
  • Determine what and how you are going to measure (metrics).
  • Establish ongoing content considerations (e.g., what will be your most effective content considering dwell time?)
  • Choose the right CMS (Content Management Software) to meet your specific application.

…all these steps come before the choice of display technology.

After you have answered all the key questions, you are now ready to choose hardware. Display technologies are abundant.  

Projection Technology (with LED or Laser Light Engines) provide the most cost-effective solution for large display needs. One can use multiple projectors blended together for additional brightness and mapping to provide almost unbelievable depth to the projected image. However, the biggest challenges with projection include:

  • Ambient light – you just cannot outshine the sun,
  • Environment – projectors don’t like rain,
  • Space – while short-throw projectors are an option for some applications, you must have enough front- or rear-throw distance to make the image happen,  
  • The need for power for the projector,
  • A suitable screen surface to complement the projector in the environment. There can’t be any mullions to take away from the quality of the image projector!

Flat Panels – Proven and getting better every day. Today, panel manufacturers continue to raise the bar on resolution, brightness, contrast, color saturation and duty cycle. The bezels continue to get smaller and with the LED light engine, durability even in 24/7 (given the panel is actually rated for 24/7) is many years. Dependability is rock solid.  Today’s large panels (90 inches and above) are often more cost effective than mounting four small panels to achieve the same display size, (so no mullions to contend with). While today’s panels weigh much less than their plasma predecessors, one still has to make sure the wall or the ceiling supports are up to the task. Video walls today embrace scaling technology (sometimes called matrixing) to achieve large sizes, but the bigger you go, the more panels you need and the more the bezels distract from the quality of the image. Flat panels can be very bright and can even be used outdoors (e.g., menu boards in fast food drive-thrus), but even these super bright outdoor panels are challenged to produce image quality in direct sunlight and may experience isotropic failure due to sunlight and heat (i.e. to turn black and become useless).

Direct-Emit LED – With the evolution of the LED Direct-emit surface and ever increasing resolution and decreasing dot pitch, the LED direct-emit surface is very hard to beat. It has a brightness that can work in the very tough ambient conditions, weather hardiness that stands head and shoulders above the projector and flat panel solutions, so if the budget will allow, the LED direct-emit is a definite go to. LED direct-emit surfaces continue to come down in price, but are still several times more expensive than the traditional video wall solution for same size comparison. If viewing distance is important, Direct-emit LED surfaces get better the further away you are. While they do technically have mullions, they are so small that unless you are standing immediately in front of the display, they are hard to see. These displays also bring flexibility to build display surfaces that would be considered mosaic or non-uniform aspect ratio surfaces, which is a major plus for catching attention but a challenge for creating content.

Bottom Line: There is no Best Display Technology. There is only the display technology that meets the needs of your digital signage objectives and budget. It still comes down to asking the right questions to be able to identify the correct solution.

About Author

Senior Solutions Specialist
Unified Technology Systems, A Solutionz, Inc. Company

Pro AV Council

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