How to increase the brightness of LED screen?

There are two ways to increase the brightness of LEDs. One is to increase the light emission of the chip itself; the other is to effectively use the light generated by the chip to increase the amount of light irradiated in the expected direction. The former is to try to improve the luminous efficiency of the chip's active layer, improve the chip shape to increase the external light extraction efficiency, or to increase the light emission by making the chip larger and using high-density current; the latter is to use light wave control technology, that is, to use packaging resin to form a special optical structure, so that the light generated by the chip is irradiated in the expected direction. If the brightness of the LED screen is found to be less than the expected value after use, you can also try to increase the brightness using the following methods.

1. Change the current flowing through the LED. Generally, the continuous operating current allowed by LED tubes is around 20 mA. Except for the red LED which has saturation, the brightness of other LEDs is basically proportional to the current flowing through.

2. Take advantage of the visual inertia of the human eye and use pulse width modulation to achieve grayscale control, that is, periodically change the width of the light pulse (i.e., duty cycle). As long as the repeated lighting cycle is short enough (i.e., the refresh rate is high enough), the human eye cannot feel the jitter of the light-emitting pixels. Since pulse width modulation is more suitable for digital control, today when microcomputers are widely used to provide LED display content, almost all LED control systems are usually composed of three parts: the main control box, the scanning board, and the display control device. The main control box obtains the brightness data of various colors of a screen pixel from the computer's display card, and then redistributes it to several scanning boards. Each scanning board is responsible for controlling several rows (columns) on the LED screen, and the display control signal of the LED on each row (column) is transmitted in series. There are currently two ways to transmit display control signals in series: one is to centrally control the grayscale of each pixel on the scanning board. The scanning board decomposes the brightness value of each row of pixels from the control box (i.e. pulse width modulation), and then transmits the opening signal of each row of LEDs in the form of pulses (1 for lighting and 0 for non-lighting) to the corresponding LEDs in series by row to control whether they are lit. This method uses fewer devices, but the amount of data transmitted in series is large, because in a repeated lighting cycle, each pixel requires 16 pulses at 16 grayscale levels and 256 pulses at 256 grayscale levels. Due to the limitation of the operating frequency of the device, the LED screen can generally only achieve 16 grayscale levels.

3. The content of the serial transmission of the scanning board is not the switch signal of each LED but an 8-bit binary brightness value. Each LED has its own pulse width modulator to control the lighting time. In this way, in a repeated lighting cycle, each pixel only needs 4 pulses at 16 grayscale levels and only 8 pulses at 256 grayscale levels, which greatly reduces the serial transmission frequency. This method of decentralized control of LED grayscale can easily achieve 256-level grayscale control.