Versatile, energy efficient, and attention grabbing, light-emitting diode (LED) displays are growing in popularity as an effective signage option in a wide variety of applications. An emerging technology, tens of thousands of LEDs combine to present a bright, beautiful, eye-catching display in pictures, videos, and other formats.

Photo courtesy of Draper Inc.

The versatility of LED means it can work in nearly any space—inside or out. Uses include wayfinding and advertising.

From advertising the latest sales to restaurant menus to corporate branding to public information messaging, LED displays are an effective way to communicate key information.

To optimally design, size, and mount these displays, an in-depth understanding of LED display technology, mounting systems, installation parameters, and project planning is essential. Further, the LED display will only project the highest-quality visual if it is mounted with a high-quality structure capable of offering a very fine level of adjustment and high precision.

Comparing LED to LCD and Projection

In analyzing LED, the technology offers a number of advantages in the realm of lifespan, brightness, power use, and configurability.

For starters, LED displays are capable of operating 80,000 to 100,000 hours before reaching their half-life. In comparison, the half-life of liquid crystal display (LCD) is 50,000 hours, and with laser projection, it is 20,000 hours.

Putting this into perspective, an LCD video wall lasts approximately five years and needs to be serviced annually to calibrate color and brightness, whereas an LED display can last for approximately 10 years and only requires a one-time calibration during initial setup. Consequently, when calculating the initial setup, lifespan, and maintenance, any LCD/LED cost gap quickly closes.

In addition to longevity, LED technology has the ability to be exceptionally bright, with levels ranging between 800 and 10,000 nits. Nits is the measured intensity of visual light, with one nit equaling one candela per square meter. In contrast, LCD video wall displays range from 350 nits to 700 nits, and projection offers roughly 500 nits in a dark room.

These brighter outputs allow for LED displays that can compete with direct sunlight, which is a noted advantage for outdoor and window displays.

“The most obvious advantage with direct-view LED is the largest and brightest video images without the noticeable seams that you see with LCD video walls and with contrast ratios that you just cannot achieve with projectors,” states Scott Simpson, CTS-D, DMC-D-4K, audiovisual consultant, associate, PAE, Portland, Oregon.

To better qualify a display’s brightness, it is important to understand emissive, transmissive, and reflective technologies. LCD uses a transmissive display, which means that the light emitted from a backlight is transmitted through the LCD layer and is then diffused. This results in a much more subtle appearance and also lower contrast.

Projection uses a reflective technology that does not perform well in bright ambient light conditions. This is due to the reflection of the surrounding ambient light on the surface of the screen, which washes out the image and results in very poor contrast.

As opposed to LED displays, which can selectively power each pixel, with no need to power the pixels in the black spaces, LCD and projection technologies use a light source projecting a constant brightness over the entire active image area, although some LCDs have dynamic backlight that helps reduce power consumption. Because of this, the power consumption will be fairly constant regardless of the content being shown. Further, commercial applications are typically set at the brightest available setting, which also consumes the most power.

Because LED is an emissive technology where light is emitted directly from each LED or pixel, the power consumption is directly related to the brightness of the content shown on each pixel. So with proper content creation, focusing on darker backgrounds with higher contrast, an LED display can yield lower power consumption.

In typical indoor applications, LEDs are generally set to a level that is below 50 percent of the display’s capable brightness. If content is created with power saving in mind, and an ambient light sensor is employed to manage the brightness throughout the day and night, the overall power consumption will be even lower, as the black areas will remain unpowered, and the overall display will dim and brighten as ambient conditions allow.

Regarding configurability, LED offers a high level of flexibility since the video walls do not need to fit within a certain standard aspect ratio, such as 4:3 or 16:9. The LED display uses LED panels that allow for a modular display configuration, so arrays can be 2x2, 2x4, 2x8, or any number of configurations. The LED video wall can also be quite large and still deliver a high-quality image.

Here Simpson notes that LED video walls support wider off axis viewing angles than LCD or projection.

Another advantage is the way in which the LED panels are designed to fit together seamlessly. This allows for content to be displayed without any visual interruptions of seams between displays, as is seen in LCD walls. While both LED and LCD can display the same content from multiple sources, the seams in an LCD video wall can interrupt or cover over text in the content.

Whereas LED has traditionally been a costly technology, this has been changing. In recent years, a narrow pixel pitch (NPP) LED display would have cost the end user roughly five times or more than LCD or projection for the same size video wall display. But today, the price gap is getting closer to equal.

In making a cost comparison, this depends on the pixel pitch of the LED display, which is the spacing of the pixels. LCDs and projectors typically have a fixed pixel quantity of roughly 2 million or 8 million depending on full high-definition or 4K, which is a horizontal display resolution of about 4,000 pixels, so the cost per pixel is not directly related to the number of pixels. An LED display has a varying quantity of LEDs (pixels) based on the total size of the display and the pixel pitch, which is defined as the space between pixels. If a display has a pixel pitch of 1.9 millimeters as opposed to another display of the same size using a 2.5-millimeter pixel pitch, the 2.5-millimeter display will have roughly 24 percent fewer LEDs and cost roughly 24 percent less even though the display size is the same.

Overall, the total cost of LED ownership is typically lower because LEDs last much longer.

Photo courtesy of NEC Display Solutions

Since LED technology is much brighter than projection or LCD, when the module’s brightness level is turned down, this enables energy savings and increased longevity.