How are the A-gauge and B-gauge of LCD divided?

                                                                            Grades of LCD panels

The LCD panel can be divided into three grades: A, B, and C according to the quality. The basis for the classification is the number of dead pixels. However, there are no relevant international rigid regulations, so the grading standards of different countries and regions are also different.
Under normal circumstances, the number of dead pixels of the LCD panel is less than 5, which is class A, the number of dead pixels is more than 5 but less than 10, it is class B, and the number of dead pixels is more than 10, it is class C. In principle, A-level panels are most suitable for the production of displays, but it is inevitable that LCD panels will produce B-level panels, so most of these B-level panels will be digested by no-name display manufacturers. The C-level panels are completely unsuitable for the production of displays, and most of them are cut into small-area liquid crystal panels for use in other fields.

However, there are also very few LCD display manufacturers who use C-level panels. Two or three years ago, there was a turmoil in which low-priced and low-quality LCD monitors disrupted the market.
Of course, in addition to the number of dead pixels, the performance of B-class and C-class panels cannot be compared with A-class panels in other aspects. Compared with A-level panels, B-level and C-level panels have relatively uneven brightness, relatively insufficient color saturation, poor image color reproduction ability, and may even be damaged in appearance.
In addition to using professional instruments to determine the level of the LCD panel, consumers can also use the naked eye for intuitive identification. It's best to use a known A-level panel for comparison, and the B- and C-level panels will show up immediately. In addition, panel manufacturers also divide A-level panels into three ladders: A, A+, and A-. The best-quality LCD panels are suitable for consumers who have higher requirements for display quality.
Under normal circumstances, the number of dark points of A-level panels is less than 3, the number of bright points is also less than 3, and the sum of bright points and dead points is less than 5; the number of dark points of A-level panels is less than 3, And the entire screen has no bright spots, and the number of dead pixels is less than 3; the A+ panel has neither bright spots nor dark spots, and the number of dead pixels is 0. A few LCD display manufacturers claim that their display products have no bright spots, and their LCD displays use A+ grade panels.