| abstract |
Provided is an optical film that has excellent characteristics such as transparency, heat resistance, solubility in organic solvents, and coefficient of linear thermal expansion. Also provided are products or members, with high requirements for heat resistance or coefficient of linear thermal expansion, that use the provided optical film. In particular, a transparent substrate using said optical film is provided, as are an image display device and solar cell containing said transparent substrate and the optical film. The provided optical film is a polyimide having a specific structure in which the repeating unit of the macromolecular chain has both an amide group and an imide group and the macromolecules contain fluorine atoms. The optical film is obtained by mixing a desiccant and an imidization agent into a polyamide acid solution and performing imidization. |