Brightness regulating method, regulating system and displaying device

A brightness regulating system, wherein the brightness regulating system comprises:

• a controller and a backlight module that are electrically connected;
• the backlight module is configured for providing a backlight source under controlling by the controller;
• the controller comprises an area dividing and light regulating unit and a controlling unit;
• the controlling unit and the area dividing and light regulating unit are electrically connected, and the area dividing and light regulating unit and the backlight module are electrically connected;
• the area dividing and light regulating unit is configured for, when an area-delimitation controlling signal emitted by the controlling unit has been received, according to the area-delimitation controlling signal, dividing the backlight source into a plurality of light areas;
• the controlling unit is configured for acquiring and storing maximum grayscale values of the light areas and a maximum grayscale value of the backlight source;
• according to the maximum grayscale values of the light areas and the maximum grayscale value of the backlight source, obtaining first brightness parameters corresponding to the light areas;
• according to the first brightness parameters, obtaining a second brightness parameter;
• and emitting the area-delimitation controlling signal and a light regulating signal;
• and
• the area dividing and light regulating unit is further configured for, after the light regulating signal has been received, acquiring the second brightness parameter, and according to the second brightness parameter, regulating brightnesses of the light areas.