LED electronic screen stage rental design 5 elements

LED electronic screen rental screen is generally divided into the main screen, secondary screen, expansion screen and floor tile screen, etc. Before the installation of the project, the general LED display manufacturers or contractors will issue a complete solution, such as LED rental screen spacing, installation Site environment, steel design drawings, prices, technical parameters, etc. The following LED display manufacturers briefly introduce the five major elements of LED electronic screen stage rental design.

1, LED electronic screen stage rental screen classification

1.1 stage rental main screen: LED electronic screen main screen generally refers to the largest screen in the center of the stage, its shape is rectangular, with 16:9 and 4:3 ratio or according to customer specified long and high size installation, its function is to play The content required for the stage performance, if it is live, then the refresh rate and display effect of the LED display are relatively high, generally require a refresh rate of 1920Hz or 3840Hz, grayscale 14bit or 16bit, contrast 3000:1 or 5000:1, The models are P2.5, P3, P3.91, P4, and P4.81, etc. (In the case of the same screen area and configuration, the smaller the spacing, the higher the screen height).

1.2 Stage Leasing Secondary Screen: The secondary screen is the LED electronic screen on both sides of the main screen. Generally, it is the left and right 1-4 secondary screens, which are customized according to customer requirements. Their role is to set off the main screen. The display content is relatively abstract, so the refresh rate and spacing requirements are relatively low, you can choose the screen with the same spacing as the main screen, or the screen with larger spacing (lower cost), such as P5, P6, P6.25 and so on.

1.3 Stage Leasing Expansion Screen: It is generally used in large venues with large venues, such as large-scale evening parties, concerts, sports events, and live broadcasts. Its role is to allow distant audiences to watch performances or events on the field by expanding screens. The installation location is on the left and right sides of the venue. Because it is a live broadcast method, the screen size, refresh rate, and display effect are similar to those of the main screen. You can select P2.5, P3, P3.91, P4, or P4. 81 other models.

1.4 stage rental tile screen: stage rental LED tile screen is divided into fixed installation and rail mobile installation, if it is only temporary use, you can choose the way of mobile installation rail, and vice versa, choose to install. Generally, in order to better enhance the atmosphere and follow the human body's activities to present instant image effects, LED display manufacturers will add interactive sensor effects, namely, LED interactive tile screens, which can enable actors and audiences to walk through, with water ripples under the feet, flowers open. And other effects. Its model is generally P3.91, P4, P4.81 and P5.

2. Packaging Technology: The performance of LED rental screen is related to the packaging technology of the driver chip, lamp bead chip, bracket, gold wire, and LED display manufacturers. Now the commonly used indoor LED display is a three-in-one package, ie, red. The green and blue light emitting dots are encapsulated and synthesized in the same light emitting tube. The SMD has the features of good heat dissipation, uniform color, large light emitting angle, good color mixing effect, soft light emission, and high-definition video playback. General indoor LED display In order to make it more high-contrast, more clear colors, longer life, etc., generally choose SMD black light and money package.

3, stage rental screen spacing: point spacing is what we usually call the pixel pitch, that is, the distance between the lamp beads and the lamp beads, generally used to represent the distance behind the P (in mm), such as P2.5 The point spacing is 2.5mm. There is another meaning behind the number of P, that is, the most suitable viewing distance (unit is m), such as P2.5 is the most suitable viewing distance of 2.5m, that is, when people stand at 2.5m to see P2.5LED display No graininess and streaking. Now people are looking for more comfortable viewing effects, LED display manufacturers generally recommend that the screen be made into a 16:9 golden ratio. The following table shows the pixel spacing, minimum line-of-sight, and 16:9 golden ratio screen size of the LED electronic large-screen model given by China ICT LED display manufacturers.

model

Pixel pitch (mm)

Minimum viewing distance

Viewing distance (m)

Pixel density (point/)

16:9 (1920*1080) screen size ()

P1.25

1.25

1.25

1.25-10

640000

2.4*1.35

P1.388

1.388

1.4

1.4-12

519064

2.66*1.5

P1.5625

1.5625

1.6

1.6-14

409600

3*1.69

P1.667

1.667

1.7

1.7-14

359856

3.2*1.8

P1.875

1.875

1.9

1.9-15

284444

3.6*2

P1.923

1.923

1.9

1.9-16

270442

3.69*2.08

P2

2

2

2-18

250000

3.84*2.16

P2.5

2.5

2.5

2.5-20

160000

4.8*2.7

P3

3

3

3-22

111111

5.76*3.24

P3.91

3.91

4

4-25

65536

7.5*4.22

Above P2.5 in the above table is a small-pitch LED display, in which PP1.25, P1.667, P1.875, P1.923, P2.5, and P3.91 are close to the 16:9 golden ratio and are the same. Under the screen area, the smaller the spacing, the better the display effect. If you need to magnify the signal by 3-4 times on a screen of the same length, then the two high-definition screens displayed by them need to be magnified by 2 times. At the same time, an HD image processor is required, and the smaller the distance, the more expensive it is. . According to the size of the screen can choose P3.91LED rental screen as the main screen, P4 as a secondary screen.

4, LED electronic screen rental scene shooting requirements: high-brush high-gray LED rental screen to meet the requirements of high-definition camera, but when the big screen to switch different screens, or camera in different shooting angle, lens focal length is different, sometimes Watch water ripples or other different colors. The reason for this phenomenon is that the spatial frequency of the CCD (or CMOS) pixels of the photosensitive element is close to the spatial frequency of the (LED) stripes in the image, resulting in moire.

This kind of moiré phenomenon can be eliminated theoretically. LED display manufacturers choose to superimpose a layer of optical processing screen on the surface of the LED display screen. The screen is composed of a special proportion of special light-absorbing material and the surface bead lens coating, through the optical The use of the screen, the LED screen from the original grid-like light into a continuous surface light, through the discrete LED pixel zoom display, and ultimately in the optical processing screen surface to form a continuous high-definition image, while improving the contrast , retains higher clarity and eliminates moire.

5, LED display control circuit design

LED electronic screen display effect is determined by the LED control part, that is, the control circuit built-in high-performance single-chip micro-control chip, the controller sends control signals and data to the LED driver chip through the internal control program, LED driver chip receives the signal, the Corresponding actions, so as to control each of the red, green, and blue LED light emitting chips individually.

5.1 LED drive system: The LED drive system includes a constant current drive, a voltage regulator circuit, and a constant voltage-constant current drive. Its function is to receive color data and drive the LED display to display the brightness value represented by the data.

Constant current drive circuit output current is constant, the output DC voltage changes with the load resistance changes, the entire circuit is not afraid of load short circuit, but the load is strictly prohibited open circuit. The voltage regulator circuit outputs a fixed voltage, and the output current changes with the increase or decrease of the load. The entire circuit is not afraid of the open load, but the load is strictly prohibited. Constant voltage and then constant current mode is the most ideal drive circuit, not only to detect the LED current, but also control the LED voltage, help to improve the LED life, reduce power consumption, generally used in high-grade LED products.

5.2 Control System: LED display control system is to control the power output of the LED, and the display effect of the stage rental screen depends on the size and time of the voltage and current passing through it. Current high-reliability LED power supplies commonly use PWM (pulse modulation) control methods, and their output voltage or current is very stable, and the conversion rate is as high as 80%-90%.

The PWM can control the proportion of time the LED is turned on and off. By dividing the time ratio into several levels, the LED displays a corresponding number of gray levels (gray scale). The product of the gray levels of the three primary colors is the number of colors that the display can theoretically reproduce, typically 256 levels, and the number of colors is 256*256*256 equal to 16.7M, which can display 24-bit true color information. In order to avoid flickering and scan lines during viewing, the PWM frequency is generally greater than 100Hz. The leased LED electronic screen has a grayscale level of 14 bits or more. The refresh rate is higher than 1920Hz, and the refresh rate of a good LED rental screen can be as high as Above 3840Hz, it can meet the requirements of high-definition camera shooting without stripes.

LED electronic screen stage rental overall solution

5.3 LED control system and drive system: The stability of the LED display screen is related to the circuit connection of the drive system and the control system. Generally, it is divided into series, parallel and hybrid, in which the safety factor of the series is the lowest, ie if there is one in the series circuit. If the components are damaged, the entire line will not be bright. It is necessary to carry out investigations one by one to waste human and material resources. However, if one LED is disconnected in the parallel circuit, the other LED current will increase, which will easily damage all the LEDs on the circuit.

5.4 Hybrid mode and loopback: In order to avoid failure during the use of the LED lease screen, LED display manufacturers recommend that customers select the hybrid mode, that is, use the series and parallel mode in the large screen to perform parallel grouping, and then each The groups are connected in series. This way, the current and voltage of each LED can be the same and the brightness is the same. In order to avoid the LED temperature is too high, you can increase the LED temperature negative feedback in the constant current output. In addition, a loop backup function is also needed, that is, when a power supply fails, other standby power supplies will automatically continue to work in place of the damaged power supply, without affecting the normal use of the LED rental screen.

The above is Shenzhen LED display manufacturers introduce the 5 elements of LED electronic screen stage leasing design - essential knowledge of the project, including the classification of the stage rental screen, the size of the dot spacing, packaging technology, shooting requirements and control circuit design, in order to ensure the stage rental The requirement for live screen without stripes requires the LED display to have high brush and high ash requirements. Second, in order to ensure the normal operation of the screen, we must choose loopback.