LED FAQ

LED Screen Frequently Asked Questions

What is a LED?

LED is short for light-emiting diode. LED screens are made from many smaller light emitting diodes placed close together. Each LED emits three colors – Red, Green and Blue – which together light up as needed to create a range of colors. The colors combine to create an image.

What is a Pixel?

Pixel is the diminutive for picture element. Pixels are points of light that illuminate at the same time to form letters, words, animations and videos. A pixel can be formed of one or more LEDs of the same color or of several colors. A pixel is the smallest element of a LED screen (or LED wall) that can be individually monitored. It can be switched off or switched on at different intensity levels.

How are LEDs different from traditional screens?

While traditional LCD screens are typically used inside, LEDs are effective in practically any environment. They are designed to remain bright and visible even under direct sunlight and withstand most weather conditions. Unlike LCD screens, they are extremely durable and can be used for projects on a much larger scale.

What is pixel pitch?

Pixel pitch is the distance between the center of an LED and the LED next to it. The smaller the pixel pitch, the better the resolution and picture quality of the LED.

What can LEDs be used for?

LED screens can be used for practically anything. Any image or video can be shown on them. Our engineers here at Street Communication can manipulate LED screens into a wide range of shapes and sizes, creating endless possibilities. Furthermore, LEDs work well both indoors and outdoors as they are exceptionally durable.

Which screen is best for me?

Choosing a screen is difficult because many factors need to be taken into account. Typically screens with smaller pixel pitches are superior indoors, while those with larger are better outside. We offer consultancy to help you reach a decision, so please reach out to us.

How does the viewing angle affects the image quality?

Making the smartest choice for your LED display can be difficult depending on the context of your project. The viewing angle depends on the brightness of the screen. Depending on the angle the viewer is watching the screen, colors and saturation can vary and give the image a blur effect. To chose your display wisely, read more on viewing angles.

How does the pixel pitch affect the screen resolution?

Before choosing your display your should know a few tricks that will help you take the right direction. Depending on the viewing distance needed for the project, the pixel pitch of the LED display is the first information you want to look for, read more on pixel pitch, resolution and ideal viewing distance here

How are LED displays better than Video Projectors?

Video projectors often seem like an easier and cheaper solution, but they dont display the same quality image, the same brightness and can’t adapt to any context like innovative LED displays do. To understand better those differences and the assets of LED displays, learn more on the article.

Understanding the scan mode of a led wall screen

The scan mode of a LED wall screen can be an important parameter to choose between several tiles. The scan mode has indeed an impact on two parameters of your screen: the light perception and the electric consumption. It must be associated with a third parameter, the refresh rate which, if high, can compensate for a low scan ratio.

There are several modes of scanning: static mode, 1/2 scan, 1/3 scan, 1/4 scan, 1/8 scan, etc.

What is the scan mode can of a led wall screen?

Principle Simplified: Each micro controller has a number of pins and can drive up to the same number of led chips. Each chip manages a led line. The scan mode determines the ratio of the number of lines of led piloted simultaneously to the total number of lines of each module.
Let’s take a concrete example: a module of 144 led divided into 12 lines of 12 led. A controller will control this module according to one of the scan modes.

  • When the module is off, no LEDs are lit. The controller does nothing.module-led-eteint-300x298

  • Static mode: The controller manages all lines at the same time. All led lines are on at the same timemodule-led-allume

  • Mode 1/6 scan: the controller manages 1/6 of the module lines at the same time, or here, 2 lines out of the 12.scan1-6anime

 

When it comes to our screens, all the lines should be lit. When one looks at the screen with the naked eye it is actually the impression that emerges. But in reality this impression is due to our retinal persistence because only 2 lines out of the 12 are lit simultaneously. However, the refresh rate of a screen is always higher than the capacity (speed) of perception of our eye.

If the sweep rate was reduced enough, we would not see the module turned on but we would see scrolling separately the lines as in this animation .

  • 1/4 scan mode: the controller manages 1/4 of the module lines at the same time, ie 3 lines out of 12.

  • Mode 1/2 scan: the controller manages half the lines of the module at the same time, ie 6 lines out of the 12.

 

How does the scan mode of a led wall screen affect its rendering?

Brightness: Theoretically, the more the scan mode of a led wall screen is weak and the less the LED wall screen is bright. Thus (theoretically) a “static” mode scan is twice as bright as a 1/2 scan, which is itself 2 times brighter than a 1/4 scan, etc. In reality it happens that manufacturers use a high mode scan to be able to use LEDs intrinsically less bright or to reduce the power sent on good led. In both cases, the two factors (good scan mode but reduced power) can cancel each other out.

Power consumption: In the same way on theoretical level, the higher the mode scan, the greater the power consumption. A “static” mode scan consumes twice as much as a 1/2 scan, which is itself 2 times more consuming than a 1/4 scan, and so on. It is often to avoid excessive consumption of scan modes too high that the power is often reduced by the manufacturers.

Finally, even if an excellent scan mode is often a guarantee of quality that is paid for by a high cost, it is not the panacea. The important thing is to find the right compromise between a good scan mode, a good refresh rate, a reasonable power consumption and a correct cost.

Diffusion on a LED wall: a necessary preparatory work

The LED wall is not equipped as standard for broadcasting images, videos or applications. A number of accessories are required.

Each slab must have one or two electronic signal receiving boards installed. They are the ones who will transmit the stream to the screen in a format that the latter can understand and play.

Receiving cards must communicate with a broadcasting card. This must be added to the system. It serves as an interface between a multimedia source and the reception cards by “splitting” the overall image and sending it to each of them. The programming of the card is obviously not always an easy thing.

If the image to be broadcast is not in the format of the screen, a converter must be added to overcome this problem and adapt the stream to the physical size of the screen. Then the diffusion on your led wall becomes perfect.

Again upstream, in order to broadcast heterogeneous sources, the addition of a multiplexer makes it possible to connect the different sources that will be sent to the transmission card or to the converter.

Each accessory must be programmed to operate perfectly with the screen and the diffusion on led wall that you have chosen.

Then you need only a source (camera, DVD player, video player, …) to broadcast something.

With the multiplexer, you can connect all your sources in one go if you want, and then, very simply, select the one you want to broadcast. Or even switch from one to the other at the push of a button or a remote control. Equipped with an internet connection or a TV decoder you can even use your giant screen as a home theater. Full HD products are available for this purpose.

Is an LED wall more ecologically? The LED wall has a longevity advantage over other imaging technologies.

The LEDs have a lifetime of more than 100,000 hours which allows intensive use of the screen for years. If a subassembly fails, the image wall can be repaired by replacing a single subassembly. The repair may concern a power supply, a reception card, or even a simple LED.

Your screen is not a consumer product. It does not go to the trash at the slightest problem and can be maintained over time.

In terms of power consumption, the wall of LED can be more or less gourmand according to its technical characteristics: Indoor or Outdoor, from 1/12 Scan to static scan and also adjustment of LED power. Associated with a brightness sensor, it is possible to adapt this brightness to the environment of the screen and thus reduce its power consumption. Overall an LED wall screen, with the same surface, will have a power consumption equivalent to a LCD TV with LED backlight, so less than a pure LCD and much less than a plasma screen.

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