Commercial Integrator August 2022 - 13

Different Technology,
Different Manufacturing
First, the technology and the manufacturing
for DVLED are different from those for
LCD displays or digital imager chips for
projection. A light-emitting diode (LED)
is a semiconductor device that emits light
when a voltage is applied to it. Electrons
in the semiconductor recombine with
electron holes, releasing energy in the form
of photons (light). Properly defined, this
is electroluminescence, in which the material
emits light in response to an electric
current. Discrete LEDs are " placed " on a
circuit board in groups of three or four red,
green and blue subpixels to create the full
color spectrum and images we see. Among
manufacturers, there are significant process
differences in how a DVLED display is built.
Think R&D and quality control.
Speaking of quality, the differences can
be substantial. Many think that an LED is an
LED, but that is only partly true. The core
concept of how they work (electroluminescence)
is common to all, but LEDs come
from a few suppliers (four to six are the
best known) and at various quality levels.
Think " good, better, best " from a given
supplier. The common differences in LED
" grades " lie in brightness, color accuracy
and lifetime. The LED is not the only difference
in quality, either. The way the circuit
boards are manufactured, as well as the
ancillary components, vary in quality. Gold
wire is at the top, followed by copper, etc.
DVLED display performance can vary
widely among manufacturers. The quality
of the LEDs and components they use
drive these performance differences, as do
manufacturing processes and quality-control
considerations. The differences we see
on the surface lie in brightness, contrast,
color saturation and uniformity.
It may appear at first glance that display
applications are similar, but the decision
of which display to use is driven (or, at
least, should be driven) by the application
and the environment. LED expands on
the available choices. If a project calls for
a fixed screen up to 100 inches diagonal,
then (in most cases) LCD has become the
most logical choice. If the application is for
larger screens, then the decision choices
are as follows: projection, videowalls comcommercialintegrator.com
posed
of LCD displays or, finally, DVLED.
DVLED shines (pun intended) by being
seamless, with high brightness, high
contrast and vivid color saturation, but it
comes at a premium price. Don't be blinded;
one size (or type) does not fit all.
Different Systems Design
The systems design for DVLED is different.
This is a natural extension of DVLED's
variability: indoor versus outdoor, straight
versus curved, nontraditional aspect ratios
and shapes, and even transparent options.
Perhaps the biggest design consideration,
however, lies in the choice of pixel pitch,
or the distance between pixels. You might
be asking yourself, " Why? " Well, it's
because, depending on the pixel pitch
between discrete LEDs, you might be able
see the individual pixels when viewing the
display. Unlike the fixed resolution that we
see with projection and LCD flatpanels,
there is a wide variety of choices within
DVLED. Pixel pitches range from (approximately)
0.5mm to over 20mm. Whether a
viewer sees pixels is dependent upon the
viewing distance.
DVLED shines (pun
intended) by being
seamless, with high
brightness, high contrast and
vivid color saturation, but it
comes at a premium price.
From a budgetary perspective, the
tighter the pixel pitch, the higher the price.
For most of us, the " sweet spot " is where
the viewer does not see pixels from their
expected viewing position. Thus, a key
element of system design is to match the
pixel pitch with the viewing distance.
The installation is different, as well.
LED displays are typically composed of
building blocks called cabinets. The LED
modules are then installed on the face of
the cabinets. Unlike LCD flatpanels, with
their VESA mounts, and unlike projectors,
with their universal mounts, DVLED displays
are not standard. They are not universal in
size, shape or weight. Thus, they require a
custom mount. In addition to the mounting
method, there is the size, weight and location
to consider. As with an LCD videowall,
the wall or ceiling structure must be sufficiently
robust to accommodate the display.
There are also differences in wiring. Some
displays are simply daisy-chained between
the cabinets and panels, whereas others
feature a wireless design.
The manner of display servicing is also
different. Depending upon the installation
type and location, service may come from
the front of the display or from the back
- or, in some cases, both. It is a matter of
accessibility. In addition to all the other
differences, in some cases (especially
outdoors), the installation may require
adherence to local codes, which might
include having a certified sign installer do
the installation.
Assessing Our Level of Risk
As you can imagine, with so many DVLED
manufacturers and so many differences,
the performance, lifetime, prices and,
frankly, risks are very different. With flatpanel
LCD displays and projectors, what
you see is what you get; it's relatively easy
to compare specifications and prices. A 4K
flatpanel or an 8,000-lumen projector defines
what they are, what they do and what
to expect regarding performance and
price. Are there differences? Of course!
But there is an established (and agreed
upon) level of quality from the major suppliers
in each category.
We do not have this level of knowledge
and experience when it comes to DVLED.
Knowing the differences in what we know,
and what we don't know, about each
display technology type is key to our level
of risk. In DVLED, separating the good from
the bad is job one. The biggest concerns
should be quality, performance and serviceability,
but price is right up there at the
top, too. The price challenge: Spend no
more than you need to, but no less than you
should. The overall " sweet spot " is where
you want to end up.
My advice? If you do not know DVLED,
work with someone who does!
Alan C. Brawn, CTS, ISF, ISF-C,
DSCE, DSDE, DCME, is the
principal of Brawn Consulting.
AUGUST 2022 Commercial Integrator
13
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Commercial Integrator August 2022

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