One of the key elements of a digital signage deployment is the display.
Technically, people will be looking at the content — text and images — shown on the displays. But without the display hardware, there’s no signage… and the decisions you make in selecting displays have a strong impact on what people will see — along with the influencing the initial and ongoing costs of your digital signage network, and its capabilities.
Here’s a look at some of the things you’ll need to know about the displays available — and how to select displays that will match your needs.
Plasma may still be popular for TV and movie watchers, but for digital signage, LCD flat panels are the clear winner. “Plasma has issues like image retention that make them less appropriate for digital signage,” says Becky Connors, product marketing manager for display vendor Planar Systems.
Within the LCD camp, there’s a new-ish choice in terms of how the backlighting is done: CCFL (cold-cathode fluorescent lamp), or the newer LED approach. “The differences are pretty drastic,” notes Connors. “Using LED backlights means a slimmer ‘profile’ — a less thick display unit.” A CCFL backlit LED panel is about 4 to 5 inches deep, while LED ones can be 60 percent less deep.
This difference can be particularly significant for displays that are being mounted in public spaces, as the Americans with Disability Act (ADA) requires displays jut out from the wall no more than 4 inches. With CCFL LCDs, this meant the display had to be recessed into the wall, which added time and expense to the installation, preventing some locations from getting digital signage. “With a thinner LED LCD, a simple wall mount will suffice,” says Connors.
“If you can meet ADA requirements regarding the maximum amount a display sticks out without having to doing recessed walls, you’ll save a lot of money,” says Mike White, CEO, MultiMedia Solutions, which does primarily digital signage for corporate accounts, along with for government and military locations.
LED backlit LCDs may also use 30 to 50% less power than CCFL LCDs, according to Planar, which can be significant for deployments with hundreds or thousands of digital displays. And, points out White, LED-based backlit displays should last longer than CCFL LCDs.
According to Lyle Bunn, an independent advisor at Bunn Company who has assisted in hundreds of digital signage deployments, “A flat panel consumes about as much power as a mini-fridge. The ability to reduce electrical power consumption can be important to LEED building certification and to energy reduction goals, as well as exhibiting a corporate commitment to conservation.”
And, says MultiMedia Solutions’ White, “Today you need to be sensitive to whether the customer has a preconceived idea that LED backlit is significantly better or not than CCFL backlit in terms of better color. LED gives longer life, but an integrator needs to be sensitive to what the customers’ impressions are, and if there are any existing loyalties to CCFL backlight LCDs. Both of the LCD platforms work extremely well. The LED backlit tends to be thinner, and have a more modern look.”
Displays come in two main product families: “consumer” and “commercial.”
“Consumer” displays are the TV and computer monitors for home and office, advertised in newspapers and sold in “big-box” stores and other retail/reseller outlets.
“Commercial” refers to displays intended for applications like digital signage. Commercial displays will generally cost more than a consumer display of the same size — with good reasons.
“Flat panels intended for TV and consumer use generally do not include features common in commercial-grade displays,” states Lyle Bunn.
Display features to consider in selecting displays for digital signage include:
Brightness: Commercial displays capable of greater brightness (measured in “nits”), which can be seen better even in bright sunlight, are becoming available. Planar, for example, offers commercial displays from 500 to 1,500 nits. “500 nits is considered the minimum for digital signage,” says Planar’s Connors.
For comparison: Normal TVs are typically between 300 to 450 nits.
Also, notes advisor Lyle Bunn, look for brightness control, such as the ability to turn down brightness during the evening when it isn’t as needed to reduce power consumption. “Auto-brightness controls can automatically adjust the brightness based on external light conditions,” he says.
Duty Cycle: Most television displays are intended to be used no more than 8-10 hours per day. Some monitors log usage internally, and overuse will void the device warranty. Displays intended for digital signage need to be capable of operating anywhere from 18 hours aday to continuously 24x7 without degrading the components or suffering from “image retention” (the LCD display equivalent of plasma “burn in,” resulting from static content if the display isn’t turned off periodically for at least an hour).
Power Controls: Does the display support an internal timer to allow the screen to have some scheduled “rest time” (display off) during hours of non-use? Does it have an RS-232 port, so the player can control display on/off?
Inputs: Does it have the proper inputs, and the proper number of inputs?
“VGA is still a fine input for digital signage, you don’t necessarily need a display that includes DVI or HDMI inputs, says Morgan Williams, digital signage account manager for KIPP Visual Systems, a provider of digital signage and other visual communications solutions. “However, an HDMI connection will carry the audio along with the video. If you decide to include audio in your signage, using HDMI reduces the number of cables to the display. Similarly, displays that can be used as TV or computer displays will let you also run an RF (radio-frequency) signal.”
Here are more of the features and concerns to pay attention to, along with trends, advice, and how to make position the buyer’s expectations so they won’t miss-focus on price instead of capabilities.
Speakers: “Built-in speakers make it easy to include audio content,” notes Williams.
Mounting: “The flat panel should install easily and be firmly, safely affixed using standard mounts,” says Bunn. “A VESA mounting standard is well proven.”
If you plan to attach a content player such as a small-form-factor (SFF) PC behind the display, “many displays don’t come with a bracket to mount a PC,” says Williams. “And remember that somebody will need to be able to get to that computer after the display is installed. If the display is 10 feet up in the air, they’ll need to be hooking up a mouse and keyboard while they’re on the ladder. On the other hand, putting the player in a data closet means you’ll be running between the closet and the sign when working on things.”
Integrating the Displays: “The flat panels should integrate well with the media player and provide the functions needed in the overall system, like color-calibration, playout monitoring, and on/off control,” says Bunn.
Bezel Size: “Does the bezel size — the margin of the manufacturing enclosure itself — complement the use of the display?” asks White. “For example, if you want to do a 2x2 video wall, or a 1x3 video ribbon, the display margins matter, in terms of impact and to look modern versus out of date.”
Video Tiling: If you are considering “tiling” — combining two or more physical displays to show one larger image — consider choosing displays that have built-in software to handle tiling, so you don’t need an additional processor to create a large display array. Also, look for displays with the narrowest possible bezel.
Cooling: “Consumer-intended panels use convection to dissipate heat generated by internal lamps,” says Bunn. “Commercial-grade panels actively cool the device by internal fan, reducing the strain and wear on the electrical components.”
Physical Durability: For digital signage that will be in public spaces where people and things may bump into them, or for signage that are also touchscreens, it’s important that the display and the enclosure be durable.
And you’re not just looking for features. “Determine whether the screens have any operating challenges,” says White. “For example, the cooling systems in some displays require the display be in ‘landscape’ orientation. If the screen will be in ‘portrait’ orientation all of the time, will that impact the warranty?”