Seeing Through Transparent LED Digital Signage

May 9, 2019 Joey Davis

The LED Digital Signage industry is driven by constant innovation and a recent advance in this space growing in reputation is transparent LED technology. While a traditional LED display mounts pixels onto solid boards or tiles and then mounts those onto cabinets or frames, a transparent LED display instead typically mounts pixels right onto a thin, skeletal grid or flexible film. In theory, this framework is designed to allow viewers to see through the gaps in the grid to objects on the other side of the display, thereby rendering the display itself effectively transparent. This sort of technology would be ideal for the windows of a retail façade, manufacturers say, because customers outside the store would be able to see both the digital content of the display and the products behind it, while customers inside the store still enjoy the ambient light entering through those windows. These displays have made a splash at trade shows and consumers have gotten excited about the potential to transform their windows into digital canvasses. The trade show environment shares little in common with real world applications of display technology however and customers would be well served to exhibit some skepticism towards what manufacturers actually are selling with their transparent LEDs. Perhaps picturing these displays work in practice similarly to the CGI holograms of Hollywood, customers have set their expectations incredibly high for the performance level of these products and transparent LED manufacturers have done little to temper these overzealous expectations. Transparent LED is quite effective in highly specific use cases, but right now it’s too niche of a product to be broadly successful in traditional direct view LED installations. To give customers a more realistic look at why this is the case, let’s attempt to see through the current state of transparent LEDs.

LED Digital Signage: Blinds vs. Curtains

The first thing to look at when considering transparent LED displays is of course their transparency. Though the degree of transparency of each display ranges by manufacturer, most transparent LED displays provide something in the neighborhood of 75% transparency. That seems pretty good, but remember that the framework of the display does not tint the window but rather physically obstructs it. In this regard, a transparent LED display is analogous to a window blind where a traditional LED display would resemble a blackout curtain. Window blinds are useful for letting in light but hardly anyone would consider them transparent, even when angled to allow the greatest degree of visibility. Furthermore, the skeletal frame of the display is not the only piece of hardware. Wires and mounting equipment, while smaller than traditional structures, are still present. If a display like this is installed onto a retail façade window, those outside will see the LED Digital Signage display but those inside will see the display, too. Instead of seeing the content on the pixels however, they’ll be seeing the rear of the display. Stores generally have windows so shoppers outside can see in and shoppers inside can see out; with a transparent display in the way, neither action is as easy as it should be.

Display Performance is Middling

In environments where high levels of ambient light are present, the brightness level of a display becomes paramount to its effectiveness. Transparent displays, designed for windows and other glass panels, are designed for use in these high light settings. But how well do they compete with other light? Most transparent LED manufacturers claim their products can shine between 1,000 and 1,500 nits, a fine brightness level for interior spaces. However, when competing with the strength of sunlight, which reflects off shiny outdoor surfaces with around 2,200 nits, 1,000 nits is not going to get the job done. If a transparent LED display can’t even reach that brightness, what daytime usefulness will it really bring to a naturally lit environment? Granted, transparent displays are designed to showcase the scene behind them as well as their own content, but if the goal is to use the display to attract customers’ eyes to the products behind, the display needs to be noticeable in the first place. Another brightness issue relates to the display’s contrast ratio. With ambient light surrounding the display from all sides, especially behind it, a transparent display is going to struggle to show the contrast ratios audiences expect from a traditional LED display. Doing so would require a higher brightness threshold, but again, these displays might not be able to hit those levels.

The next consideration for customers should be pixel pitch, the measure of how closely together adjacent LED units are aligned and a good barometer for digital image clarity. Combing through the various model lines of transparent LED display manufacturers, customers will find that the smallest pixel pitch any of them offer is slightly above 3mm. This is adequate for many purposes but that it represents the lower bound of transparent LED pixel pitch is a bit limiting to customers with more ambitious goals. Spacing pixel pitch closer together is likely achievable for many of these manufacturers but doing so will compromise the transparency of the display. Manufacturers are left with a choice: do they prioritize image clarity or image transparency? Customers can’t really have both right now.

Price is High, Practicality is Low

Transparent LED is a relatively rare technology, and as such, its costs are often prohibitive. While this technology avoids many of the mounting and weight-related expenses of traditional LED displays, manufacturers have yet to optimize production and several, including Samsung and Planar, have actually discontinued their transparent OLED models in the face of insufficient demand. Researchers from MIT have explored using nano-particle scattering to create the effect of a transparent display inexpensively, but there is a wide gap between research lab experiments and commercial availability. These displays are fascinating but currently they are the digital signage equivalent of a concept car. Fascinating to look at and to discuss, but ultimately impractical and years away from true viability. Manufacturers build these incredible solutions for the purpose of showing off what the future might look like, failing to explain to customers that these solutions are not in fact the present. Essentially, transparent LED displays are the coolest thing you think you want but they fail to do everything you actually need.

What Do You See?

Upon addressing each of these realities with transparent displays, customers have a fundamental question they should ask themselves: what do they want their LED Digital Signage to accomplish? If you want your display to showcase eye-catching digital content, there are other technologies better suited to that task. If you want customers outside your store to see your products inside, a regular window does that job just fine. Similarly, if the ambient light flowing into your space through your window is valuable to you, or the ability to see outside is valuable to your customers, perhaps adding what amounts to digital blinds isn’t the best idea. Transparent LED manufacturers are advertising a product that does the jobs of both a window and a display, but in trying to be both these things, a transparent LED display is actually neither. Inquiring minds can find further reading about pixel pitch, brightness levels, and the future of the LED industry on our website!


The post Seeing Through Transparent LED Digital Signage appeared first on NanoLumens.

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