What are the existing types of the external screen?
So let’s begin from the classification of the big street screens by the type of light source used for forming the image. These are the widespread lamp screens and ledscreens, and also they are gas-discharge and projecting. Discharge screens in turn are divided on two subgroups. The first works by the principle of an electron beam tube (CRT), i.e. the stream of electrons bombards a phosphor layer, which shines as a result with that or another colour. In general, everything is like in a usual television kinescope, but there are a lot of such kinescopes in a big street screen and they are much less in their size than the smallest television kinescope. Due to the small sizes of such CRT it is possible to get a sufficient brightness of a luminescence and to apply the screens in the street in the afternoon. A good example of such type of screens is Jambotron by SONY –company.
The second subgroup includes the screens with the electroluminescent principle of a luminescence, which is similar to the principle used in fluorescent lamps or neon sources. In this case the gas filling a such lamp changes its condition (is ionizing) under the action of an electric current and begins to shine. The screens of Hungarian firm MEGALUX can serve as a good example. In due time the similar screen has been established on a stadium “Petrovskey” in Saint Petersburg. In both cases the high voltage (about several KV) is needed for functioning of a screen. The consequences are the insufficiently high reliability of discharge screens, their petulance in a work and low parameters of working resources of radiators and the labour inputs of their replacement.
Projecting screens, in turn, are also divided on two subgroups-these are the screens with a frontal projection and rir-projectors (rear-projection), in which the projection of the image occurs from the back side. Besides the projecting screens are also divided on two models by the light source type-the screens with projective kinescopes (CRT-projectors) and projectors with ZK-matrix (LCD-projectors). Their advantage is the very high quality at the rather big sizes of the image. It makes them indispensable during different presentations and mass actions.
Everyone who is interested in details can address to an article “Videoscreens on the streets. Is it an alternative to TV?!
”, published in October number of magazine “Advertising technologies” and in Internet –magazine “Alternative TV
What is the ledscreen?
|This is a screen ,in which the semi-conductor led is used as a light source. The ledscreens are divided on two types by the principle of construction-these are the cluster screens and matrix screens. In cluster screens every pixel, containing from three up to tens leds ,is incorporated in a separate light isolated body which is filled in with a proofing compound .Such constructive element is called the cluster. The clusters, which form an informational field of the screen , are fixed by means of screws on an obverse surface of the screen. Every cluster gives a bundle of wires,which goes to an appropriate operating plateau and is connected with it by means of electric sockets. Such way of construction of the fullcolored ledscreens gradually dies off, giving up the place to more technological matrix principle. In this case the clusters and the operating plateau are united into a single whole- the so-called matrix, in other words, on the operating plateau there are mounted both the leds and the switching electronics which are filled in with the proofing compound. Depending on the size and the resolution of the screen the amount of leds making up the pixel can vary from three up to several dozens. And the distribution of leds by the coloures in the pixel varies from the type of used leds in interests of observance “balance of white”.|
What is the lamp screen?
|In lamp screens the usual automobile incandescent lamp with a power rating 5 Wt is used as a source of light. Each of such lamps is placed in the optical system like an automobile headlight. This system consists of a reflector and an optical filter. The reflector focuses a light stream in strictly certain direction, and the optical filter paints it in one of three primary colours. Besides, each row of point light sources is covered from above by the small awnings, which serve for protection of a radiating surface of the screen against hit of direct solar beams. All these in the result raise up the picture contrast.|
How is it correctly to choose the screen?
When you want to choose a concrete model of the electronic screen, first of all it is necessary to be finally determined with a place of its installation, if it means the stationary screen instead of mobile. Half of success of all enterprise depends on the correctly chosen place. After the place has been chosen it is necessary to be defined with the size of the screen and the way of its installation. The size of the screen depends on two factors:
1.the electronic screen should be blend with the chosen place harmoniously;
2.the chosen size of the screen should be corresponding with your financial opportunities.
After you have chosen the size of the screen it is necessary to choose the type of the screen and its resolution. About the preferable type of screen you can find out from the next question. Speaking about the resolution it is necessary to mean the following moments: the resolution influences on the quality of the picture and on the price of a screen. Thus the average resolution of a screen is usually enough for displaying advertising or another information because the visual contact to the screen lasts basically from 5-10 to 30-40 seconds. For this period a person simply will not have the time to distinguish any details. By the way it is necessary to remember about this fact at creation of advertising rollers. It is also important to take into account that even the high resolution should not let you to sell a minute of the advertising time by the higher price.
We’ll give you an example. The size of the screen is determined and makes up 6x4 meters. The choice of the type of a screen is rather simple: lamp screen with such dimensions has the resolution not higher than 80x52 pixels. Such resolution is not enough for the fullcoloured image that is why we’ll choose the ledscreen. Between the ledscreens we can choose electronic boards with different resolution. The most expensive and high resolution is 384x288,further is the resolution 288x216,224x168 and at last the cheapest resolution is 144x108. The most preferable variant is a screen with the resolution 224x168 pixels. Such resolution is quite enough for displaying video rollers and transmitting the television broadcast. Thus the price of such screen is twice as little than the price of a screen with resolution 384x288 and the same size.
What is the more preferable kind of screen –ledscreen or lamp screen?
Choosing the type of screen it is necessary to take into account, that the lamp screen has a great size because of the big size of incandescent lamp and of the optical system. That is why the least size of a lamp screen with the resolution 112x84 pixels makes up 8,5 x 6,4 meters. The optimal size for the lamp screens with the resolution 160x120 pixels is 12x9 meters. Besides, lamp screens consume much more electric power.
So the difficulties can arise at allocation of brought capacity from urban services. But thus the lamp screens are cheaper than the ledscreens with the similar sizes. So you wouldn’t forget about the lamp screens, especially if it is necessary to establish an electronic screen or a panel of the impressive sizes (for example on a roof of a building, on a stadium) in conditions of limited financial opportunities, but if there is a powerful source of the electric power nearby (the railway, for example).
In other cases it is better to prefer the ledscreens and panels.
What is the pixel?
Pixel- (from the words “picture element”-is the element of the image) represents an elementary colour point, which forms the image with other such points. Pixel is the basic element of raster images.
What is the cluster?
Cluster is a light source; which constructively unites a group of leds located in one common light isolated and damp-proof case. Clusters can differ:
-by the form and the sizes (cylindrical,rectangular,etc.);
-by the amount of leds;
-by the reproducing colours(monochrome,bicoloured (RG),fullcoloured(RGB)).
What is the brightness of the screen ?How is it measured?
Brightness of a light source or of an illuminated surface characterizes a level of light irritation in a human eye and by that a level of light sensation registered by brain. For example, you look at a luminous surface from any certain distance. So, the force of light of this luminous surface divided on the area of this surface seen by your eye is called the brightness. A unit of measurement is candela on sq.meter(cd/m2) and in foreign sources it is nit (nt), 1nt=1cd/m2.
With reference to videoscreens the maximal brightness is measured on a pique of white, when the surface of a screen shines with a white colour. Only in this mode all light radiators work with maximal efficiency and the maximal brightness is achieved.
What is the resolution of the screen?
The resolution of the screen is the ability of displaying system to reproduce separately fine details of the original. This characteristic is one of the most important characteristics of videoscreens. It is evaluated in the amount of points of the image (pixels) on two coordinates: X and Y. There is a standard line of resolutions: 160x120; 320x240; 640x480; and their derivatives. So the image will be more detailed if the numerical value of resolution is higher.
What should be the resolution of the external electronic screen?
To answer this question it is necessary to put another question : what should be the minimal sufficient resolution for the video image with reference to external screens? There is no well-defined answer. The corporation Microsoft, for example, considers that this resolution is 160x120 pixels. We think ,proceeding from our experience, that the resolution of 128x96 pixels is the minimally sufficient for the external electronic boards. Thus it is necessary to take into account that the low resolution will not look well under the big size if the screen. So the screen in the size 16x12 meters with the resolution 128x96 pixels will be looked rather mediocrely,especially close to it. On the other hand ,the resolution higher than 320x240 pixels is unreasonably high for the external screens and it leads to the unjustified starting charges and charges on the electric power. The truth is somewhere in the middle. But always there are the exceptions, which confirm the rules.
What is the "balance white"?
Many of you still remember from school lessons of physics that for painting a light stream in any colour it is necessary to mix three basic components in the necessary proportion: red (R), green (G) and dark blue (B). If all three colours radiate with identical intensity we shall receive a luminescence of white colour (actually, for reception of white luminescence it is necessary to take the components with the certain weight shares, but for simplicity we shall consider them the equal). The color TV is based on this principle, the same principle is put into functioning of fullcoloured external screens.
The so-called "balance white" is the basic criterion of correctly constructed system of displaying the information. If the "balance white" is not sustained, the image will have this or that shade, and the white colour will give to blue, green or redness. Observance of "balance white" causes the formation of a pixel by mixing of three basic colours in different proportions, depending on the type of a light source. For example, in lamp screens the pixel is formed of one red, one green and two dark blue point radiators.
What is the control system of the electronic screen?
It is a complex of programs and hardware, which forces each light radiator of the screen to shine in a necessary way for forming the raster image. Easier speaking, it is a set of controllers and a computer ,which display the image. The operator sets a necessary algorithm of functioning of the screen and operates its control system. Thus the constant "watch" of operator is not required.
What is a mobile video screen?
|Mobile video screens are generally used during some kind of mass entertainments, one-time actions, and presentations. In other words video screens are used when it's necessary to install a big screen for a brief time.|
There are two kinds of mobile video screens: movable and quick-installed. Movable screens are based on chassis of a track or trailer. As usual such screens are equipped with autonomous power supply system, with unfolding to an operating mode system and mini-studio from where screen broadcasting is operated. It takes 20 or 30 minutes maximum to unfold such kind of screen into an operating mode.
Quick-installed LED screen is just a standard LED screen which is transported to any place into separated modules and from which it is assembled. In this case a frame with modules of a screen is to be fixed to concert poles or to any other load-bearing unit. And it's necessary to supply it with the electricity. It takes about 2-6 hours to install a screen.
In general quick-installed LEDs are used to carry out any actions or entertainments in a field environment, and movable screens are mostly used for concerts and other entertainments of this kind inside the same as outdoor.
|Конкретные вопросы по нашей продукции, расценкам и свои предложения, пожалуйста, отсылайте из раздела Контакты/Предложения|