LED display screen: those advantages and disadvantages
A light emitting diode screen (LED screen) is an information display device in which an image is formed by a plurality of semiconductor LEDs located on the surface of the screen. Each point on the screen is a pixel and can contain one or more LEDs. Today, LED screens are one of the most promising visualization tools. This is why they are increasingly used as information boards, billboards, and even just as creative elements of decoration.
- The working principle of LED screen
- LED screen equipment and classification
- The choice of LED screen
- Advantages of LED screen
- Disadvantages of LED screen
- Application of LED screen
The first working prototype of the LED screen was exhibited at the EISEF Technology Exhibition in the United States on March 18, 1978. Compared with the popular CRT monitors at the time, James Mitchell, the author of the development project, said that its main advantages are simple image formation and low operating voltage, which will allow the use of LED screens on portable devices in the future. Through the battery. Thanks to OLED technology-Organic Light Emitting Diodes (OLED), miniaturization of LEDs to the size required for traditional TVs only took place in the 21st century.
The LED screen is not the first technology to reproduce dynamic images, but the first to have such a wide range of capabilities. Comparing day and night full-color images, digital content, flexible display settings, and arbitrary geometric shapes of the screen itself, LED screens become a powerful tool for conveying important information to consumers and customers.
The working principle of LED screen
The LED screen is equipped with three basic colors of LEDs-red, green and blue (RGB). The combination of these three color LEDs, working with different brightness, allows you to create any full-color image. This principle is similar to that of a traditional TV or computer monitor
The LEDs on the screen correspond to pixels, but unlike the LCD screen, the pixels of the LED screen are virtual, that is, LEDs of the same color can be part of multiple virtual pixels. This feature allows you to obtain twice the image resolution.
LED screen equipment and classification
The LED screen adopts a modular design. The LEDs are combined into clusters or matrices and connected to the control electronics from the back. These individual modules, also called cabinets, operate independently, but can be combined into a single piece in any configuration. Therefore, traditional rectangular screens and screens of more complex shapes can be constructed-curved, protruding, and repeating the shape of their mounting surface. The main characteristics of the cabinet are resolution, pixel pitch and size.
According to the design, LED screens are divided into cluster type and matrix type.
Cluster screen
In the cluster screen, each pixel is a separate element, containing multiple LEDs, ranging from three to dozens. The cluster is completely sealed and equipped with connection connectors. The cluster can be encapsulated in a shell, and can also be equipped with other equipment: lens, reflector, sunshade, etc.
Historically, the cluster technology first appeared as the logical development of the first LED screen. It was composed of lights and had a linear architecture. One of the pixels was a light and a control board.
Among them, one pixel of the image is composed of four light-emitting elements-red, blue and two green light-emitting elements, and is drawn into an overall structure together with the control board. Then connect this design to the module controller. With the development of LED technology, it is possible to place all the LEDs of a pixel on a semiconductor substrate with a single control electronics, which makes it possible to not need to fiddle with each LED, just combine the cluster and the control board. Currently, cluster LED screens are considered obsolete, but still have applications because they are no worse than matrix from an operational point of view.
Matrix screen
The matrix screen is more technical. Among them, the cluster itself and the control board are a whole, the on/off of a single pixel is performed through the information bus, and each module is connected to the information bus.
Through the placement of LEDs, the screen is divided into DIP and SMD screens-Direct Insert Package and Surface Mounted Devices clusters respectively.
Dialing screen
In the DIP screen, the traditional three-color bulb LED is directly mounted on the base. Due to the size of the bulb LED, the pixel pitch of the DIP screen is rarely less than 7 mm. Therefore, this type of LED screen is more commonly used outdoors, and the device housing has an appropriate climate design. In addition, DIP screens are brighter, which also determines their use under bright natural light.
Patch screen
In the SMD screen, R, G and B-LEDs are concentrated in one place on the substrate. At the same time, the physical size of LEDs does not exceed a few millimeters, which means that they are no longer visible to the naked eye, even if they are fairly close. The pixel pitch in the SMD screen can reach a value below 1.6mm, that is, the resolution of this screen is significantly higher than that of the DIP. Therefore, SMD technology is more commonly used for indoor screens.
According to the design, LED screens are divided into internal (for indoor use) and external (for outdoor use). The outdoor screen is designed and manufactured with a closed climate, has a waterproof shell, and is resistant to high temperature and sunlight.
According to the existence of the shell, the LED screen can be divided into two types: the shell type and the open frame type. In the first case, the screen size is large and a special structure is required for installation. For example, special glue that hardens under the influence of ultraviolet radiation is used to stick open screens on the inner surface of the glass of the display cabinet or on the wall. This technology makes it possible to obtain transparent display cases that replicate advertising videos or interactive materials.
The choice of LED screen
When choosing LED screen, pay attention to several parameters:
brightness
The brightness of the LED directly affects the perception of information by the LED screen, especially the screen installed outdoors. The optimal brightness of an outdoor screen is considered to be a luminous intensity of 8000 candela per square meter. For a screen installed indoors, 2500 candela per square meter is sufficient.
It should be remembered that the passport value of luminous flux power may be different from the true value. Therefore, you should not chase the cheapness of Chinese LED screens without first ensuring that they do have the declared characteristics, alas, this is not always the case.
Best viewing distance
As mentioned above, a large pixel pitch is not necessarily a disadvantage. It all depends on the viewing distance. The simple approximate formula for calculating the minimum observation distance is also given above:
Therefore, for a screen with a pixel size of 3 mm, the minimum distance at which the image looks smooth is about 4.5 meters. Conversely, if the viewing distance is known, the formula can be used to determine the pixel size required by the LED screen.
Pixel pitch
According to the maximum viewing distance, the required screen size can also be determined. The maximum viewing distance is defined as twenty times the height of the screen, namely:
Maximum viewing distance = screen height * 20
Therefore, if the image on the LED screen is to be readable within a distance of 150 meters, the vertical size of the screen should be at least 5-8 meters. Then the horizontal size can be easily calculated based on the required aspect ratio, ie 4:3 or 16:9
Fault tolerance
An important parameter not only determines the service life of the media facade, but also determines its resistance to various external influences. High-quality display manufacturers use only high-quality components: high-quality Nichia LEDs can achieve brilliant color reproduction, all high-quality displays have redundant configurations to achieve hardware flexibility, use a unique steel EGI housing to help extend the life of the device, and more. Therefore, when choosing an LED screen, it is better to see more and more clearly, or to believe that professionals are better.
Advantages of LED screen
Durability
The service life of modern LED screens can reach 100,000 hours. But it should be noted that during the life of the LED, the brightness of the LED will gradually decrease, and the brightness will drop by 50% after running for more than 10 years.
Modular
The modular design of the LED screen allows you to arrange the LED light groups as you like, without seams and visible seams. In this case, the screen size can reach tens of meters, and the arbitrary configuration of the modules allows the use of unusual design schemes and non-standard forms of information boards, video walls or billboards.
Easy to install and maintain
The LED screen is characterized by simple installation and switching. If necessary, the screen can be expanded very quickly. At the same time, there is actually no need to maintain the LED screen. The integrated design of the LED module can withstand external influences. If necessary, the light board can be extended by installing additional cabinets. It is also simple to replace the faulty module.
Bright picture and perfect color reproduction
Unlike LCD screens, LCD screens are based on the translucent technology of the liquid crystal substrate and the LED lighting of the LCD matrix. The LEDs of the LED screens emit light. Thanks to the arrangement of modern ultra-bright diodes and up to six diodes per pixel, today’s LED screens display excellent image brightness, and the information from them is fully readable even on bright days. In addition, it is worth noting the ability to adjust the brightness of the LED, because the maximum brightness is not required at night. The viewing angle of the LED screen reaches 140 degrees, and the picture does not fade under extreme viewing angles, and the color is not distorted. Very high contrast shows excellent image quality.
High vitality
One characteristic of LED technology is that there is no inertia at all. The LED processes the control signal with minimal delay and immediately changes its brightness. Therefore, even the most dynamic video on this type of screen can be reproduced perfectly, without delays, “gap” and artifacts.
flexibility
The LED module can be installed not only on a flat surface, but also on a curved surface. But in addition to constructive flexibility, LED screens are also flexible, allowing you to copy content from a variety of media. In this case, the configuration of the screen is done programmatically, usually remotely.
Effectiveness and efficiency
In any case, the LED screen looks great. Bright and dynamic images on the screen can convey absolutely arbitrary information to consumers according to their choices. At the same time, such content is more eye-catching in the context of traditional billboards and signs. It captures the attention of customers faster and more firmly, and actually combines the advantages of TV or media advertising with the simplicity and simplicity of traditional billboards. Reliability is combined. By correctly choosing the format and content of the content displayed on the LED screen, the latter is not only effective, but also a very effective information transmission tool.
Disadvantages of LED screen
At the same time, LED screens also have some shortcomings that should be considered:
Relatively low resolution
Because the steps between LEDs are large enough (average-10 mm), LED screens cannot boast of high resolution. Therefore, information about them must be read from a certain minimum distance, so that the individual pixels of the screen cannot be distinguished. This distance can be approximately determined by multiplying the passport pixel pitch by 1000. For a screen with a pixel pitch of 10 mm, the minimum viewing distance is 10 m; for a screen with a step length of 25 mm, the distance is already 25 m, and so on. Therefore, knowing the distance at which content should be viewed on the LED screen, you can determine the required pixel pitch. For example, if the LED screen will be installed on the roof of a building, and the minimum viewing distance is 30 meters,
High power consumption
Since LEDs emit light by themselves, the power consumption of large LED displays can be very large. For example, the average power consumption of an SMD technology cabinet with a resolution of 32×32 pixels and a pitch of 10mm is about 40W. Therefore, an 8 x 6 meter screen composed of such modules will consume an average of 5.7 kW or more.
Relatively high price
Although the technology of LED display is developing dynamically, the price is still expensive. Other types of outdoor advertising are much cheaper. On the other hand, LED screens have no direct analogues, and their unique advantages fully prove their high cost.
Application of LED screen
The application of LED screens goes far beyond the scope of replacing billboards. Judge for yourself.
Outdoor LED screen
They are used as dynamically changing signs and billboards. They can often be used as media facades, showcases and original advertising designs. Moreover, the information displayed on the LED screen can even be targeted at a specific person! It’s not hard to guess that with such techniques, you can quickly attract the attention of your target audience and achieve higher levels of engagement.
Indoor LED structure
Indoor LED structures can be used as decorative elements for shopping and entertainment centers, movie theaters, dining venues, concert halls, etc. In addition to the marketing function, the LED panel can also play the role of creative dynamic lighting, display the latest information (train schedule, menu, weather), and even react to external factors and adjust the content accordingly.
Video screen and video wall
Video screens and video walls are used in the design of sports facilities and concert venues. Usually, the extended LED video wall is like a huge billboard. In addition, only LED screens can be bent and have any aspect ratio.
One of the characteristics of the video wall is that the audience can cover a wide range, and the displayed content can be viewed from any location convenient for the audience.
Therefore, the LED screen is a powerful tool with a very wide range of applications and many unique advantages. At the same time, the appropriate selection and installation of LED screens need to take into account many nuances, so it is best to entrust this work to professionals.
