The Facts About Electronic Message Centers
The dynamic capabilities of electronic message centers using light emitting
diode (LED) technology continues to attract more and more customers. Schools,
fire districts, and churches use this affordable, reliable and flexible medium
to advertise events, circulate information and reach out to communities with
public service announcements.
A number of suppliers manufacturing LED systems have emerged in response to this
rising market demand. How can the quality of the displays they offer be
evaluated? This portion of our website provides you some critical points to
consider when assessing an LED electronic message center:
LIGHT EMITTING DIODES (LEDs)
LED DISPLAY LIFETIME
What affects LED display lifetime
LED COLORS & INTENSITIES
Requirements of different LED colors
LED DISPLAY CONTRAST
Effects of good and poor contrast
LED DISPLAY DIMMING
Suitable dimming for readability in all conditions
LED DISPLAY COLOR DEPTH
Determining available colors
What constitutes a video-capable display
ELECTRONIC MESSAGE CENTER INDUSTRY
Characteristics of a reliable supplier
QUESTIONS TO ASK A POTENTIAL
About their ELECTRONIC message centers
LIGHT EMITTING DIODE (LED)
"LED" is an abbreviation for "light emitting diode". An LED is a solid-state
electronic device that emits light when energized by applying power. The LED die
is mounted to a lead frame which is encapsulated in an epoxy lens. The epoxy
lens directs the emitted light and protects the LED die from physical damage. A
lead frame provides the electrical connections, the physical mounting and a
thermal heat sink to remove the heat generated within the LED. A display
manufacturer must have an in-depth understanding of LEDs and their properties,
as well as use high-quality components in order to develop effective designs
that stand the test of time.
WHAT WE DO:
- Daktronics uses LEDs from the industry’s leading suppliers and only from
suppliers capable of meeting our specifications for brightness, longevity, and
- Toth’s Sports utilizes LEDs from Daktronics. Daktronics uses more LEDs
than any other display manufacturer.*
- Daktronics has excellent relationships with the top LED manufacturers in
- Daktronics contributes to the research and development efforts of our LED
suppliers, spending significant time at their facilities reviewing processes,
communication market needs and discussing development paths.
*"Daktronics is the #1 user of NICHIA light emitting diodes in the LED
display market in America" --Hideki Kaneguchi, Manager at Nichia Corporation
"Daktronics is an AVAGO (formerly Agilent) Premier Partner. Premier partners are
long-term, high-volume Avago customers." --Jovani Torres, Regional Manager at
LED DISPLAY LIFETIME
The operational lifetime of an LED display is determined by the lifetime of the
LEDs. LED manufacturers estimate the LED lifetime to be 100,000 hours under
certain operating conditions. LED display end of lifetime is when the frontal
brightness has decreased to 50% of original brightness.
Three primary factors determine LED lifetime:
--Manufacturing process of the LED
--Driving (powering) method of the LED
--Temperatures present at the LED die during operation
LED thermal management is vitally important to maintaining LED lifetime.
Increasing the power through an LED increases brightness but reduces its
lifetime due to increased heat generation. Increased exposure to higher
temperature also shortens the lifetime. LED thermal management can only be done
through the LED lead frame by conducting heat to a Printed Circuit Board (PCB)
and by allowing airflow to cool the LED lead frame.
Led display components must be designed to handle a wide range of outdoor
environmental factors, such as temperature and humidity. All components must be
coated to protect from possible corrosion.
WHAT DAKTRONICS DOES-- Toth’s Sports utilizes Daktronics LED modules.
- Daktronics designs and manufactures its own LED modules to ensure the
consistency and quality of the manufacturing process.
--Some display manufacturers purchase LED modules from low-cost
manufacturers, who many times have sacrificed quality to ensure lower cost.
- Our LEDs are mounted directly to a Printed Circuit Board (PCB) that is
installed as part of the cabinet construction. This allows ventilated air to
cool the PCB and lead frame, thereby cooling the LED die and providing thermal
management of the heat to maintain LED lifetime as recommended by the LED
--Some manufacturers encapsulate the entire LED lead frame in a pixel
separate from the cabinet, not allowing the LED to cool through the lead
- Our display modules are manufactured using a module-coating process that
protects the displays to lengthen their lifetimes.
--Some manufacturers skip this process to cut costs.
LED COLORS AND INTENSITIES
The color and brightness emitted by an LED are determined by the chemical
composition and construction. Single-color (monochrome) displays are made up of
one color of LEDs, whereas full-color displays contain LEDs that emit red, green
and blue light. The color efficiency of the human eye has different sensitivity
to different colors, and therefore perceives the brightness of each color
The number of LEDs alone does not determine the brightness. The design, quality,
brightness, lens, and viewing angle of the LEDs, as well as the drive method and
contrast of the module, determine the overall brightness of a display. In fact,
using more LEDs per unit area creates more heat and therefore requires more
WHAT WE DO:
- Our electronic message centers are designed for proper color efficiency
matching which provides a red, amber, or full-color display with uniform
--Some manufacturers design displays for the same brightness for all
colors, which creates red displays that are too bright and amber displays that
are not bright enough.
- Our electronic display LEDs are powered according to manufacturers’
specification and use the optimal number of LEDs required for the application.
--Some manufacturers suggest that more LEDs create a brighter and therefore
better display, but as noted above, this may not always be the case.
LED DISPLAY CONTRAST
Along with the proper brightness, a display must have high contrast for good
readability. Contrast is the difference between the background’s "off state"
(blank display area) versus the "onstate" (illuminated display area). High
contrast increases the readability of a message, much like white text on a black
background, causing readers to focus on what needs to be seen. The highest
contrast appears in a display with a dark border and a consistent dark black
background across the entire display with minimal sunlight reflection. A louver
system provides shading and black, non-reflective materials ensure the least
amount of reflection. Polycarbonate or acrylic face material may provide
sufficient contrast, although with a potential for glare, but does not provide
as high a contrast as flat black paint or a black potting encapsulant.
WHAT WE DO:
- Our LED modules feature a full-length, seamless black louver system across
the entire module, providing a consistent contrast across the complete display
--Some display manufacturers use individual louvers over each pixel or LED,
which produces a pixilated effect and adversely affect uniform contrast.
- We offer different display products with carefully selected face
materials, each having a preferred application and quality of image.
--Some manufacturers offer customers a limited selection of face materials.
LED DISPLAY DIMMING
For maximum effectiveness, an electronic message center must have the capability
to adjust brightness levels for correct intensity and high contrast according to
ambient light conditions during any time of the day. At night, during lower
light conditions, an electronic message center that is too bright due to
inadequate adjustment may be worse than a display that is too dim. An overly
bright display can be distracting and difficult to read, which can damage market
appearance and result in stricter sign codes.
A good electronic message center control system should have multiple dimming
control methods including: automatic dimming as determined by ambient light
conditions, scheduled dimming that can be preset to adjust at scheduled times
and manual dimming that instantly adjusts the brightness. Scheduled dimming is
required when an auto dimming system must be overridden to meet certain
conditions or as sign codes require.
WHAT WE DO:
- To ensure effective dimming, our electronic message centers feature these
capabilities: automatic dimming through a light sensor, scheduled or manual
dimming through software control.
--Not all manufacturers have options for automatic dimming or scheduled
dimming, resulting in an overly-bright display that will be difficult to read.
- Our electronic message centers dim to an optimal level according to
current ambient light conditions using many levels of dimming to provide
superior readability and maximum effectiveness of the display.
--Many other manufacturers’ displays don’t dim low enough in dark
conditions, or don’t provide multiple levels that allow a wide range of
dimming, resulting in unclear content and diminished effectiveness.
LED DISPLAY COLOR DEPTH
"Dimming" and "shading" refer to entirely different functions and the terms
should not be interchanged. The word "dimming" refers to a uniform brightness
adjustment across the entire display to correct intensity for ease of reading
during different ambient light conditions. "Shading", or color depth, affects
the light output variations of each red, green, and blue LED to create images
within the display.
COLOR DEPTH CHART
Each individual red, green, and blue LED can be in one of two states, either on
or off. This example uses a color data processing of 5 bits for each color. So,
each color is 2 to the 5th power and multiplying each color’s depth provides the
overall color depth of 32, 768 colors.
Although "dimming" and "shading" have different meanings, some manufacturers
will combine greyscale shading values with dimming values to create color
specification that appears more impressive on paper than it is capable of
producing in the field. Combining shading values with overall values is a
deceiving and misleading practice.
WHAT WE DO:
- Our electronic message centers are available in no shading monochrome, 64
shades monochrome, 32,768 colors RGB or 68 billion and 4.4 trillion colors for
--Many other manufacturers will combine shading and dimming values to create a
more impressive number. This practice can be deceiving.
Video can be described as displaying a moving image, which is made up of many
individual frames played at a fast rate. Good video is played at 30 frames per
second or higher. Slower rates can begin to look choppy and affect the
Video content can be "live", such as from camera feed, or "pre-produced", such
as previously recorded live feeds, or previously created content. The LED
display industry generally defines fully capable video displays as being capable
of both live feeds and pre-produced, or stored content, whereas graphic
messaging displays are only capable of pre-produced, or stored content. Many LED
display applications do not require the live feed capability or complexity of
these systems. The higher the level of expectation, the higher the required
Video graphical frames require high pixel counts and color depth to provide good
definition for highly detailed, accurate and recognizable images. Video clips can
be run on small displays with minimal color depth, but the image will look
pixilated and will lack definition; however, the results may be acceptable for
certain applications. Color depth, or levels, is the amount of color available
to portray the image. Most digital video content in 16.7 million colors, but
more levels of color depth are recommended to provide proper color matching to
the original image. Video purists suggest a minimum of 1 billion colors for the
best video images.
LED MESSAGE CENTER INDUSTRY
Since the advent of high-brightness red, green, and blue light emitting diodes
in the mid-1990’s, many firms have entered the LED display manufacturing
industry, and many have failed. To be successful in the industry, a company must
provide dependable displays capable of showing high-quality imagery, control
systems that offer creation and management of content appropriate for the needs
of each particular customer and ongoing support for many years.
WHY WE CHOOSE TO USE DAKTRONICS
BRAND ELECTRONIC MESSAGE CENTER COMPONENTS
- Dedicated to the electronic display industry since 1968.
- Since 2001, independent market research firm iSuppli Corp. lists
Daktronics as the world’s leading provider of LED displays.
- Daktronics LED displays are constructed in Brookings, S.D., United States,
on one of the largest manufacturing floors devoted to building LED displays in
the industry. Manufacturing space expands as needed, in response to changing
- Daktronics is committed to continued investment in research and product
development to expand the market.
- Daktronics is a financially stable, publicly traded company that will be
around for years to come to support your Daktronics display systems.
- Daktronics offers a comprehensive set of service options and maintenance
agreements to keep customers’ display systems operating at maximum impact.