In order to solve the problem of poor flexibility of the existing transparent
polyimide thin film, the invention provides a
polyimide polymer, a transparent
polyimide thin film and a preparation method of the transparent polyimide thin film. The polyimide
polymer has a
structural formula (a) shown in the description; the transparent polyimide thin film has a
structural formula (b) shown in the description; in the
structural formula (a),
oxygen atoms in the molecular chain are positioned in a 3nd bit or 4th bit of a
benzene ring; in the structural formula (b), A is a residual group of 3,3,4,4-Biphenyltetracarboxylic dianhydride. Synthesis monomers of the thin film comprise dianhydride and
diamine; the dianhydride comprises 1,4-bis(3,4-dicarboxyphenoxy)
benzene dianhydride and 3,3,4,4-Biphenyltetracarboxylic dianhydride; the
diamine comprises 2,2'-bis(
trifluoromethyl)-[1,1'-
biphenyl]-4,4'-
diamine. The transparent polyimide thin film provided by the invention has the advantages that a relatively flexible 1,4-bis(3,4-dicarboxyphenoxy)
benzene dianhydride structure unit is introduced into a high-rigidity structure unit, so that the anti-deflection performance of the thin film can be greatly improved; the characteristics of high
light transmission rate, good mechanical performance,
high heat resistance, good anti-deflection performance and the like are realized.