Ways to improve the brightness of LED electronic display
Brightness is a very important parameter of the LED electronic display, especially for outdoor products, during the daytime outdoor itself is relatively bright, and sometimes encounter direct sunlight, if the brightness of the LED electronic display screen can not reach, the audience will not see clearly, so that the playback effect will be greatly reduced, and even no one will go to the trouble of watching. Therefore, how to improve the brightness of the LED electronic display has been one of the key points in the research and development of LED display manufacturers. So in general, how to improve the brightness of the display? And everyone to find out.
Improve the brightness of the LED electronic display screen can be broadly divided into two methods, respectively, is to increase the amount of light emitted by the chip itself; the other method is to effectively utilize the light generated by the chip to increase the amount of light irradiation to the expected direction of irradiation. The former is to try to improve the chip active layer of light-emitting efficiency, as well as improve the shape of the chip to increase the efficiency of the external light, or the chip large-scale use of high-density current to increase the amount of light-emitting; the latter is the use of light wave control technology, that is, the use of encapsulation resin to form a special optical structure, so that the chip produces light irradiation to the expected direction.
If led electronic display screen after use found that the brightness does not reach the expected value, you can also try to use the following methods to improve the brightness.
1, change the flow of LED current, general LED tube allows continuous operation current in 20 milliamperes or so, in addition to the red LED saturation phenomenon, other LED brightness is basically proportional to the flow of current.
2, the use of the human eye's visual inertia, with pulse width modulation method to achieve grayscale control, that is, periodic changes in the width of the light pulse (i.e., duty cycle) as long as the repetition of the light cycle is short enough (i.e., refresh frequency is high enough) the human eye does not feel the light-emitting pixels in the jitter. Because pulse width modulation is more suitable for digital control, so in the universal use of microcomputer to provide LED electronic display content today, almost all of the LED electronic display control system usually consists of the main control box, scanning board and display control device three major parts. The main control box from the computer display card to get a screen pixel color brightness information, and then redistributed to a number of scanning board, each scanning board is responsible for controlling a number of rows (columns) and each row (columns) on the LED display control signal is transmitted in a serial manner.
Currently there are two kinds of serial transmission of display control signals: one is the scanning board centralized control of the pixel point grayscale, the scanning board will come from the control box of the rows of pixel brightness value decomposition (i.e., pulse-width modulation) and then the rows of LED open signal in the form of pulses (light for 1 is not light for 0 according to the line in a serial transmission to the corresponding LED, control whether it is lighted. This way to use less devices, but the serial transmission of the amount of information is larger, because in a repeat light cycle, each pixel in 16 levels of gray scale needs 16 pulses, 256 levels of gray scale needs 256 pulses, due to device operating frequency limitations, generally only make LED electronic display screen to do 16 levels of gray scale.
3, scanning board serial transmission content is not each LED switch signal but an 8-bit binary brightness value. Each LED has its own pulse width modulator to control the lighting time. In this way, a repetitive lighting cycle, each pixel point in 16 levels of gray scale only 4 pulses, 256 levels of gray scale only 8 pulses, greatly reducing the frequency of serial transmission. With this method of decentralized control of LED grayscale can easily achieve 256 levels of grayscale control.
