The following are the four core technologies of automatic adjustment of LED display brightness:

1. LED is a green light source, and its main advantage is high luminous efficiency. With the development and progress of material science, the luminous efficiency will be greatly improved in the next 10 years; low energy consumption, long service life, recyclable materials, do not pollute the environment. Although our country started late, it has also started active research and development and industrial policy and support in recent years. Compared with incandescent lamps, LEDs have a significant difference: the luminous brightness is basically proportional to the size of the forward current flowing through the LEDs. Using this feature, the brightness of the surrounding environment is measured by an optical sensor, and the luminous brightness changes according to the measured value, maintaining the influence of changes in the brightness of the surrounding environment, and construction transfers people to work happily. This not only creates a comfortable environment with constant brightness, but also makes full use of natural lighting and saves energy considerably. Therefore, the research on LED adaptive dimming technology is particularly important.

2. Basic principle: This design uses column to send data and row scan to realize LED display text or image. The method is combined with the hardware circuit to achieve the purpose of relatively uniform overall brightness of the display screen. Using the sensitivity of the photoresistor to the ambient light, the change of the ambient light is collected, converted into an electrical signal and sent to the single-chip microcomputer. A switch voltage regulator circuit is added between the single chip microcomputer and the led display screen to realize the brightness adjustment of the display screen by the single chip computer. The adjusted PWM wave is used to control the switching voltage regulator circuit, so as to adjust the input voltage of the display screen, and finally realize the brightness control of the display screen.

3. A light-emitting diode display screen adaptive brightness control circuit, characterized by comprising: a duty cycle preset value input device, a counter and a size comparator, wherein the counter and the duty cycle preset value input device respectively A count value and a duty cycle preset value are input to the comparator for comparison to control the output value of the comparator.

4. Hardware design of LED adaptive dimming system The brightness of the LED is proportional to the current flowing through it in the forward direction, and the forward current can be adjusted to adjust the brightness of the LED. At present, the brightness of the LED is generally adjusted by means of adjusting the working current or by means of pulse width modulation. The former has a large adjustment range and good linearity, but consumes a lot of power. So it is rarely used. The pulse width modulation method uses a higher frequency to switch the LED, and the switching frequency exceeds the range that people can perceive, so that people cannot feel the existence of stroboscopic. Realize LED adaptive dimming.