What are the control technologies of LED display?
Few people will go deep into the control technologies of LED display screen, on the one hand because it involves a lot of content, many words are more esoteric, on the other hand because the literature in this area is relatively small. Here we list some LED display screens control technology, so that everyone has a deeper understanding of this aspect.
With the development and use of a new generation of “array-type” control system, the birth of this generation of control system has greatly improved the technical advantages of LED screen control, and further improved the processing technology of display signals. After adopting the “array” control system, we will discuss some of its technical contents in detail.
Energy-saving and consumption-reducing technology
Due to the use of an array control system, it can effectively reduce the loss of display screen brightness caused by the control system used to generate grayscale. According to comparative calculations, the system loss of the traditional “centralized control system” is between 30% and 40%. , the system loss of the “array control system” is between 8% and 10%. The reduction of the control system loss is conducive to improving the brightness of the display screen, or reducing the current of the display screen under the same brightness conditions, so as to achieve The effect of energy saving and consumption reduction.
In the centralized control system, due to the large control range, in order to maintain a certain refresh rate, it is necessary to reduce the number of scans and reduce the brightness to form grayscale; due to the small control range of the array control system, the number of scans can be greatly increased, and the loss of brightness will follow. become smaller. The scan times of the array system can reach more than 136 fields, while the centralized type can reach up to 42 fields.
According to the principle of brightness loss, the calculation table is compared as follows: a 200-square-meter outdoor full-color display with 3906 dots/square meter, if a driving current of 20mA is used, the theoretical maximum brightness can reach 15000cd/m2, if it wants to reach 6000cd/m2 The maximum actual brightness of the display screen, using the “centralized control system”, according to 30% of the system loss, the display drive current is 11.4mA/pixel, and the maximum power supply current is 607A;
If the “array control system” is adopted to achieve the maximum actual brightness of 6000cd/m2, according to the system loss of 10%, the display drive current is 8.89mA/pixel, the maximum current is 474A, and the energy saving rate reaches 21.9%. . Calculated according to the average power consumption is 40% of the maximum power consumption, calculated according to 10 hours of use per day, 300 days per year, and the annual power consumption of the “centralized control system” is 160248 degrees. The annual power consumption of the “array control system” is 125,136 kWh, saving about 35,112 yuan per year (calculated at 1.0 yuan per kWh)
Single point detection technology
In order to improve the reliability of the screen and increase the convenience of maintenance, Yuanheng Optoelectronics has developed a single-point detection technology for the display. Usually, the detection of LED pixels before the LED display leaves the factory is through visual inspection (that is, the human eye sees whether it emits light according to the debugging program). Not high either.
Now our company uses the single-point detection function of the screen body, and only needs to run the corresponding program to judge the working state of the pixel, so as to repair it, which greatly improves the reliability of the screen body. At the same time, with the continuous development of LED display technology, super-large LED screens have emerged in the market. This type of screen is generally installed at a high position and has a long viewing distance, which brings inconvenience to the detection work of the display screen. The judgment of each pixel point can only be based on human judgment. After using the single-point detection function, the maintenance personnel can easily find the coordinates of the fault point and replace them quickly.
Single-point luminance and chromaticity correction technology
The problem of brightness and chromaticity uniformity of LED display screens has always been a major problem for the industry. It can only be improved by subdividing and filtering the LED color coordinates. As people’s requirements for LED displays are getting higher and higher, only subdivision and screening of LED color coordinates can no longer satisfy people’s critical eyes. It is achievable to comprehensively correct the display to improve chromaticity uniformity. of.
First, the brightness and chromaticity at a certain level are inconsistent due to differences in the LEDs themselves (for example: using the same current to light up two green LEDs in the same production batch, the brightness may vary by 30%, and the wavelength may There will be 10-15nm changes).
Secondly, after a period of use, the blue LED will dim the most and the red will be the least, but the biggest problem is that the LED will dim differently after a period of time. Therefore, even if the consistency of the LED screen is perfect in the factory, as the LED dims, the consistency will be lost, and the inconsistency of the LED screen will be significantly discovered after three years of non-stop use.
To this end, we use the world’s advanced monochromatic luminance and chromaticity correction technology (also known as: luminance and chromaticity signature technology) to solve the problem of inconsistent color rendering due to inconsistent attenuation of LEDs of different colors.
In terms of display technology, LCD is a display screen composed of liquid crystals, and LED is a display screen composed of light-emitting diodes. Each pixel unit in the LED digital display is a light-emitting diode, and the monochrome LED display is generally a red light-emitting diode.
From a technical point of view, the array control system solves many problems. First of all, the frame changing frequency of the display screen can be increased from the current 60Hz to more than 120Hz, which is far greater than the ability of human eyes to distinguish, so that people can There is no stroboscopic and water ripple phenomenon when viewing, which improves the display quality.
Secondly, the gray level of the three primary colors of red, green and blue on the display screen can be increased from the current 256 to 1024, which makes the color more vivid, the color reproduction is better, and the displayed image is more realistic.
Finally, the LDVS signal is used for transmission, which minimizes the loss of the signal, synchronizes the display content of the entire display, and improves the consistency of the display.
In recent years, domestic LED display technology has been further developed. my country’s LED display has occupied 80% of the global market. However, the development of LED display is not in my country. To this end, LED manufacturers such as Radisson Optoelectronics will actively develop and improve LED technology. The overall design of the LED display software control system determines the system operation process and completes the system software control function. According to the specific equipment communication requirements, the serial port communication technology is adopted. By introducing the relevant knowledge of port communication and serial port communication protocol, the communication between the control system and the hardware equipment part is realized, and the text information transmission function of the LED display screen is completed. The technical control of LED display is an important guarantee to determine the quality of the product.