As it has already been mentioned a source of light for this type of screens is a motor-car lamp with following parameters: voltage 12V, capacity 5W. This fact determines the main characteristics of lamp screens that is to say high brightness, a wide viewing angle. But unfortunately the same fact results in negative consequences – high power consumption of lamp screens (about 3.5 kilowatt/m 2 ).
Among disadvantages of lamp screens we have to mention their relatively low resolution. The problem is: when we try to increase the resolution we are to face two serious limitations:
So, a screen with lamps situated one inch one from another consumes 8 kilowatt. It makes its maintenance more expensive. And it makes a demand to a high-voltage substation that causes additional initial investment. But a price for a square meter of a lamp screen approaches to LED screens that provide much better resolution.
Reasoning from all that was mentioned before experience has shown that optimal step between lamps is 1.5 inches. It lets produce screens with not bad resolution and relatively reasonable according to the power consumption.
An optimal screen size is 9x12m, at the same time a resolution is 160x120 pixels when all these parameters are maintained a TV picture format is supported, and a visual contact with the picture is provided at the distance of 50-600m.
We also have in our model range of lamp screens an economical variant with the following parameters: 6x8 in size and with the resolution 112x84 pixels. It's evident that in this case a TV picture format is inaccessible. But according to the experience in many cases this resolution is enough for a demonstration of full advertising clips and even for video clips taken close-up.
Both these systems are full colored that is to say they represent 16.7 millions of colors. Described systems are basic. On their basis screens of different sizes and resolutions can be built.
Now let's say some words about the construction of a screen. Modularity is the principle on which the screen is built. In other words a screen is assembled with light modules like with bricks. You may see a structure of a light module on the picture. A module represents a plated circuit on which there are 64 lamps (8x8). Over lamps furniture is hafted. Furniture is a set of reflectors, color filters and visors. All these equipments combined is an optical system that makes a picture. Reflectors form a light beam the same as a motor car headlight, color filters paint it in an appropriate color and visors protect a screen from sun reflection and makes the raise of contrast. Pixel consists of four lamps and is built on the RGGB scheme. In other words RGGB scheme consists of one red, two blue and one green color filter. On a back panel of a module there are two handles to install and to dismantle it. Modules are fixed on a spatial metalware forming a screen stage by means of four studs. On the stage there are power supplies and control electronics installed. A screen is assembled from several stages. Owing to a modularity of a screen simplicity of service and repairing is achieved. The repairing consists in diagnostics of broken modules or other elements or in their replacement.
Not long ago our engineers finished and applied in industry a new control system that allows managing as lamp as LED screens. It's made on a present-day elemental base on a basis of chipsets of programmed logical matrixes. As far as computer run in lamp screens becomes complicated because of electromagnetic noise appearing during lamp communication, a system of frequent control of information transmitted via data lines was placed in operation.
It allowed to improve a picture fundamentally and to manage a general brightness of a whole screen the same as a brightness of each color separately down to the lowest levels of brightness. This possibility is a very important aspect from the point of view of practical use. It happens very often that one have to decrease a general brightness of the entire screen at a night time according to the legislative regulation and norms of state if a screen is located next to a traffic way (as it happens very often). Besides, there's a possibility to regulate a screen palette, in other words to regulate the color brightness.
At the present time all the produced screens are equipped with a new control system. And this control system is completely unified on the interface stage with earlier control systems, and it allows making an upgrade of existing and installed screens.
Technical characteristics of lamp screens
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