There are 4 main components of a led video wall
 1) The LED’s:
These were the traditional led which look like little domes with 2 wires that get soldered onto their board.
We also have ‘surface mount diodes’ (SMD) which are more flat and can represent more than one colour, these are often machine stamped into their board and appear as a flat looking diode. They have a higher brightness, are more reliable cheaper to assemble and were the industry is moving towards, but they are considerably more expensive in manufacture. Sometimes they are referred to as a 3 in 1, so they can do the 3 primary colours RGB in one SMD.
The price on all leds tend to vary considerably depending on where and buy whom they are manufactured. So the cheapest are the Chinese followed by the Taiwanese, and then the Japanese with N.America having the best and most expensive. The difference her for the same specification led can be as much as 10 fold from the Chinese to the Americans. Sometimes these differences can be blurred with Cree leds from America now being manufactured in China.
2) The Power Supply Unit:
Like Leds we have a similar pricing fluctuation depending on where these are manufactured, its important to remember that the producer of a video wall will have the choice of different compnents.
3) The Control Unit:
The control is vital for addressing the matrix of leds, and can also function within say 256 brightness levels which can be automated to cope with the brightness of the leds at times of high ambient light or when there is total light control. These can be placed away from the video wall, but will have a recommended distance which should not be extended. These systems are often made up of transmitting and receiving cards.
They should be able to cope with the most popular video standards, VGA, Pal, NTSC, and SDI etc.
4) Distribution:
This will link the source equipment to the display equipment by means of distribution amps etc.
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DOT Pitch Vs Resolution:
The higher specification has the smaller dot pitch and the more expensive price. We are now down to 4mm dot pitch at the bleeding edge.
The chart below gives you an idea of the area that is need to display at a 10mm dot pitch a standard PC resolution of 1024 x 768; we would need almost 80 square meters.
6mm dot pitch 1024 x 768 = 6.144M x 4.608M
10mm dot pitch 1024 x 768 = 10.240M x 7.680M
20mm dot pitch 1024 x 768 = 20.480M x 15.360M
Consequently in the world of ‘led’ it is normal to work of smaller resolutions as below.
On large dot pitch 160x120; 320x240; 640x480 are standard resolutions. So a 40mm dot pitch displaying 320 x 240 = 12.800M x 9.600M
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Dot Pitch Viewing Distance:
I work of the basic assumption of 1 meter viewing distance for ever 1mm of dot pitch.
So with a 10mm dot pitch we would need to be 10 meters away to start seeing the picture as opposed to the dots.
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LED Brightness:
The higher the brightness, the more expensive the led. Typically video screens for outside use will be considerably brighter and more expensive than for inside use; this is not just down to the led brightness but also due to the IP rating for facing the elements when being used outside. Internally specified leds tend to be around the 1,500 nits while leds for outside use are about 6,000 nits.
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LED Builds:
1) Tiles:
There are several popular ways of constructing a video wall. The traditional method was by arranging the leds into a tile about a half meter square. The tiles are joined together and are daisy chained for power and control. They are a solid unit. This is still the cheapest way of configuring a video wall especially one which has a high dot pitch |
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2) Transparent Tiles:
These are not transparent but are constructed on a matrix of cable within a frame type shell and have an element of transparency as there is now back plate. However the smaller the dot pitch the less transparency. These are lighter than tiles and allow PA systems to be placed behind the wall. They are also used externally on buildings for advertising as they can still allow the building architecture to be seen when used with a dot pitch of 80mm. |
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3) Webs, meshes and curtains
Are extensions of the transparent tiles, and have the added benefit of a lighter construction and are flexible. It must be remembered that besides losing transparency as the pitch size goes down, we also increase weight, so a sq meter at a 20 dot pitch may weigh 10 kilos, a 40 dot pitch will weigh about 5 kilos |
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Power consumption
Depends on dot pitch and brightness but an internal led with a 10 dot pitch will work out at about 500W per sq meter.
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