Old Dog, New Tricks: What I’ve Learned About dvLED
By Brian Rhatigan
One thing that keeps me interested in my career is that our industry is ever-evolving as technologies are introduced and evolve over time. After 17 years of working in the world of ProAV distribution, I never stop learning new things. Most recently, I was tasked with learning about dvLED to help support our sales team and customers on projects. While I still have a lot to learn, below are some key takeaways that I can share based on what I have learned so far.
Pixel Pitch and Viewing Distance
The term “pixel pitch” was new to me, but it is one of the key factors to think about when designing a dvLED display project. Simply put, pixel pitch is the measurement in millimeters between the individual LEDs or pixels, and this is measured from the center of one LED to the center of the LED adjacent to it. Naturally, as the pixel pitch value decreases, the resolution in a fixed size cabinet increases, which allows for a closer optimal minimum viewing distance.
For this reason, it is important that you discuss with the client where the closest viewer will be in relation to the display so that you can choose a pixel pitch that is appropriate for the specific application remembering that as pixel pitch decreases, the equipment cost increases. A general rule of thumb that has been shared with me is that you can multiply the pixel pitch by 10 to give you the approximate closest viewing distance in feet. So, for example, the recommended minimum viewing distance for a 2.5-pixel pitch wall would be 25 feet.
If you are like me, when you think about display resolution for common applications, it is typically 1080p (1920×1080), WUXGA (1920×1200) or 4K (3840×2160) (understanding there are many others, but these are most common). With flat panel displays and projectors, the image size can vary while the resolution remains constant. For example, a 4K display can be 55 inches in diagonal or 98 inches in diagonal, or several other sizes, but the resolution will always be 4K. With projection, a native WUXGA projector, whether displaying a 110-inch diagonal image, a 216-inch diagonal image or any size for that matter, the resolution will always be 1920×1200.
This is not the case with dvLED, as the individual LEDs or “pixels” mounted on the surface of the module are a fixed size so that when the size of a dvLED display changes, so does the resolution. To illustrate this, let’s look at a dvLED panel that is 16:9, 27.5 inches in diagonal with a pixel pitch of 1.58. The resolution of this panel is 384×216. If you require a 1920×1080 display, you will need 25 panels in a 5×5 array to make a 137.5-inch diagonal display. If you require a 4K 3840×2160 display, you will need 100 panels in a 10×10 array, making a 275-inch diagonal display that requires four times the real estate!
In many cases, dvLED displays will either be wall-mounted or flown, although sometimes they can be ground stacked with the appropriate stacking hardware. Depending upon the size of the display, they can get quite heavy. For example, a recent 165-inch diagonal display (6×6 array) I quoted weighed just shy of 500 pounds, and a 275-inch display (10×10 array) weighed over 1,300 pounds. It is absolutely crucial that the structure or wall that you are mounting the dvLED on or the structure from which you are rigging can support the load.
Additionally, in order for a successful installation, the dvLED cabinets need to be perfectly aligned along the x, y and z axes so that there are no visible seams between the individual panels that make up the display. Since most walls will have some imperfections and not be perfectly flat, you will be faced with either using shims or exploring mounting hardware that provides post-installation adjustment of all three axes.
Power and Data
Unlike a traditional flat panel or projector, with dvLED, the display does not have a single power cord. Instead, depending upon the size and resolution of the display, multiple AC circuits will be required. If we go back to the 165-inch 6×6 array I referenced earlier, this display required six dedicated 110v/10A outlets. In this case, each AC circuit is powering six panels with a main connection to the first, then daisy-chaining with power jumpers to the next five.
In addition to power, every dvLED display requires multiple data connections between the display and the dvLED controller/processor using data cabling such as Cat6. The number of data runs will vary based on the overall resolution of the display, but you can expect that the manufacturer will advise you during the proposal stage on the required cabling and power requirements for the specific project.
I see more and more projects come across my desk that involve dvLED, and there has been dramatic growth in overall product sales in the category over this last year. There is no reason to believe that these trends will not continue, and I look forward to continuing my education on the subject.