Is widely used as a background LED video screen, and has wide applications such as events, shows, concerts, performances, promotions, stages, wedding, sports etc.
With video processors, the LED display has multi video signal inputs and outputs, more funtions while displaying videos. By using standard die casting cabinet which is light in weight but durable structure, the LED display panel is much more convenience for installation and transportation.
Outdoor rental led display of HSC LED is high brightness with 5500nits. It also could reach high contrast ratio with black SMD LED even under direct sunlight. LED stage screen is perfect for stage background and events. Outdoor rental led screen is fast and easy installation with HSC LED unique cabinet design.
P4 outdoor rental full-color LED display has many characteristics, the market demand is constantly expanding Outdoor rental full color LED display is different from fixed LED display. Fixed LED display is divided into outdoor fixed installation and indoor fixed installation.
Generally, it is installed in one place and will not move for a long time; while outdoor rental full color LED display It is necessary to move to a designated venue for video playback according to the needs of performances and publicity. In order to cater to this frequently-moving studio demand, the caravan’s on-board LED display came into being. Generally, if there is no special description, the rental LED display is not only used outdoors, but also often used indoors.
It is often used in stage performances, fashion shows, temporary advertising, new product launches, and so on. The viewing distance of the rental LED display will not be too far or too close, so its specifications are between the outdoor fixed LED display and the small-pitch LED display.
The pixel pitch is generally P6.25. , P5.59, P4.81, P4.8, P4.62, P4, P3.91, etc. Below P2 is a small-pitch LED display, while those above P4 are generally outdoor fixed LED displays. Between small pitch and outdoor fixed installation, rental LED display has its own characteristics. Now we take P4 as an example to talk about the characteristics of P4 outdoor rental full-color LED display.
The P4 LED display refers to a pixel pitch of 4mm, which can be used indoors and outdoors. P4 outdoor rental full-color LED display screens are reasonably matched according to the area and viewing distance. For rental screens, sometimes it is not necessary to strictly distinguish between indoors and outdoors. It is more important to judge the approximate viewing distance according to the occasion of use, and then choose the appropriate LED rental screen. The rental company will have a variety of specifications. Rental screens are available for selection.
For P4 LED rental screens, display manufacturers generally design them to be suitable for various indoor and outdoor occasions, because LED displays of this specification are widely used and common.
P4 outdoor rental full-color LED displays generally have the following characteristics:
1. Die-cast aluminum box In fact, this is the characteristic of rental screens. LED rental screens need frequent transportation, handling, installation, disassembly, etc., which have relatively high requirements for the product’s vibration resistance, flatness, fire resistance, dust and water resistance, and the box The body should not be too heavy, which is too heavy to be transported. The P4 outdoor rental full-color LED display with a die-cast aluminum box body weighs about 8.5KG, which can be easily carried by one person, and it is also convenient to install or disassemble.
2. Highlight and brush P4 rental LED display, the pixel pitch is only 4mm, it will not appear blurry even if the viewing distance is close, the refresh rate is greater than 1920Hz, the brightness is greater than 4500cd per square meter, and the maximum viewing distance is about 4.5m, which is very suitable for indoor and outdoor stages. Leasing and advertising leasing.
3. High protection level P4 outdoor rental full-color LED displays are often used in outdoor stage performances, advertising, new product releases, etc., and the outdoor environmental conditions are unpredictable, often there will be heavy rains or even heavy rains, typhoons, etc., so P4 rental screens The protection level should be above IP65, so as to ensure its stable operation and prevent rain, dust, etc. from entering the box and causing damage to the internal components.
4. Modular design This is also a design scheme adopted to better maintain the P4 full-color rental LED display. Lease LED display screens are often disassembled, assembled and transported. In many cases, it is possible to damage the components of the product accidentally. The modular design makes maintenance easier and easy to achieve before and after maintenance, which can save time and cost. In summary, P4 outdoor rental full-color LED displays need to have many unique features.
With the development of advertising media, stage performances and other industries, the demand for LED rental screens is also increasing. Rental companies engaged in screen rentals There are also more and more, especially the P4 outdoor rental full-color LED display, which is currently widely used, but with the continuous expansion of market demand, the P3.91 rental screen is also widely welcomed by the market.
How does the outdoor creative led display steel structure achieve lightning protection Summer is the season of unpredictable weather, and wind, rain and thunder will switch randomly. Thunderstorms can often cause safety hazards to outdoor LED display screens, so how to protect the steel structure of outdoor creative LED display screens from lightning?
(1) For the lightning current induced on the signal line, install a signal lightning protection device on the signal line. The signal arrester is determined according to the signal interface of the system. If it is a network cable, install a network signal lightning arrester, and install a db9 interface lightning arrester for the serial interface.
(2) For the protection of direct lightning strikes, install lightning rods on the support structure of the LED electronic display (outdoor), indoor displays or LED displays with tall buildings next to them, you do not need to consider installing lightning rods.
(3) For the counterattack of the steel structure, connect the steel structure to the housing of the electronic display screen, do the equipotentiality, and do the grounding. The grounding resistance is usually less than 10 ohms. If the resistance does not meet the requirements, do it Additional artificial grounding grid. The lightning arrester should also be well grounded.
(4) For the lightning current induced on the power line, install a single-phase or three-phase power surge protector on the power line. The link cross-sectional area of the phase wire cannot be less than 10mm square, and the cross-sectional area of the ground wire cannot be less than 16mm square. The above points are about the protective measures for lightning protection of outdoor creative led display screens.
Switching power supply in outdoor LED display solutions Introduction Switching power supply is the main component of the LED display, and its quality and performance are directly related to the quality and life of the display. Because the characteristics of the optoelectronic devices in the LED outdoor full-color display are different from the general display, the cost is very expensive, and the performance and quality of the switching power supply are very high.
Therefore, this paper has developed a special switching power supply for the outdoor full-color display. Characteristics of outdoor LED display switching power supply The power supply used for LED outdoor full-color display should have the following characteristics.
1) Keep the LED pixels driven by a constant current under certain conditions. The voltage change of the LED group caused by the load change of the display screen will affect the pixel current and cause the brightness change. In order to ensure uniform brightness of the entire screen module and reduce brightness changes, the sampling point of the switching power supply output sampling circuit is moved from the power port to a certain point in the display screen, so that the voltage at this point remains unchanged.
The voltage change caused by the load change is adjusted by the switching power supply, that is, when the load is small, the output voltage is low; when the load is large, the output voltage is high. Therefore, it is ensured that the voltage output to the LED module remains unchanged and the pixel driving current is constant under the condition of constant temperature and brightness.
2) Compensate for the change in LED forward voltage drop VF caused by ambient temperature The LED forward voltage drop VF decreases with the increase of ambient temperature. The temperature variation coefficients of various LEDs are different. Within the normal operating temperature range, VF can vary up to 20%. Under constant voltage drive, a drop in VF will cause the LED current to rise, causing the overall temperature to rise. In this feedback process, the working condition of the LED will get worse and worse, which will seriously affect the quality and life of the outdoor screen.
Therefore, the switching power supply of the outdoor screen is required to have a temperature compensation function to ensure that the LED drive current does not increase with the increase in temperature.
The simple method of temperature compensation is to insert a negative temperature coefficient thermistor whose temperature change rate is close to LEDVF in the switching power supply, and introduce the switching power supply PWM chip to compare the reference voltage Vi (Vo=KVi). When the temperature rises, Vi drops and the output voltage drops, suppressing the rise of the LED operating current.
Due to the large dispersion of thermistors, in order to ensure the consistency of the product, it needs to be selected. In addition, there is an independent resistance combination for each temperature change rate, which is poor in interchangeability. In order to overcome these shortcomings, a digitally controlled switching power supply whose output is controlled by a digital signal is adopted. According to the temperature drift curves of various LEDs, the driving voltages that need to be provided to the LEDs at different temperatures are made into a table and stored in the single-chip microcomputer for query. According to the temperature check table measured by the temperature sensor single-chip microcomputer, the output voltage of the corresponding numerical control switching power supply can be obtained.
3) Controlling the brightness of the display screen by adjusting the voltage of the switching power supply In order to make full use of the limited resources in the full-color screen control system, the switching power supply is required to adjust the brightness of the full-color screen by adjusting the output voltage. Due to the large changes in outdoor lighting, it is necessary to tabulate the voltage values corresponding to the brightness of the full-color screen in advance according to different climates and time periods, and store them in the single-chip microcomputer. Look up the table according to the signal sent by the light sensor, and get the output voltage value of the numerical control switching power supply to control the brightness of the display screen.
The working principle of universal switching power supply The working principle of universal switching power supply is shown in Figure 1. Using 3525 pulse width modulation (PWM) components as the control circuit of the switching power supply, the function is complete and the application is convenient. The error amplifier amplifies the error signal at the output of the power supply, and sends it to the reverse input of the comparator through the sampling circuit for comparison with the ramp voltage output from the oscillator in the reference circuit.
Use the square wave pulse output by the comparator to control the duty cycle of the 3525 internal output power tube. Different voltage values can be obtained by changing the reference voltage and output sampling circuit. The working principle of CNC switching power supply CNC switching power supply is a switching power supply whose output voltage is controlled by a digital signal.