Selecting method of light guide plate of backlight module

A selecting method of a light guide plate (LGP) used in a backlight module of a liquid crystal display (LCD) panel, the selecting method comprising the steps of:

• calculating a plurality of mura indexes (MI) corresponding to a plurality of mura statuses of a plurality of first LGP types, respectively, wherein each of the first LGP types has a plurality of first dot patterns and each of the mura indexes is represented by an equation, MI=D1*T1/(P1*P1), and wherein MI represents each of the mura indexes, D1 represents a dimension of each of the first dot patterns, P1 represents a first interval distance between the first dot patterns and T1 represents a first thickness of each of the first LGP types;
• defining a plurality of film structures, wherein each of the film structures corresponds to each of mura indexes for mapping the mura indexes (MI) of the first LGP types with the film structures correspondingly to construct a mapping database;
• and
• selecting one of the film structures and one of the mura indexes (MI) correspondingly from the mapping database for determining a critical dot dimension (CDD) of a second LGP type of the selected film structure, wherein the second LGP type comprises a plurality of second dot patterns, the critical dot dimension is positively related to the mura index of the selected film structure, the critical dot dimension is positively related to a second interval distance formed between the second dot patterns, and the critical dot dimension is inversely related to a second thickness of the second LGP type, for selecting the critical dot dimension based on the mura index of the selected film structure, the second interval distance and the second thickness of the selected film structure.