Abstract: The present disclosure relates to a polyimide-based resin film wherein a thermal hysteresis gap at a temperature of 50° C. or more and 150° C. or less is 100 ?m or more and 500 ?m or less, and a substrate for display device, and an optical device using the same.

Abstract: A polyimide film according to the present invention can be effectively used as a substrate for a flexible display device without a deterioration in heat resistance even at a temperature of 350° C. or higher since a coefficient of thermal expansion (A) in the section of 100-350° C., of the polyimide film, and a coefficient of thermal expansion (B) in the section of 350-450° C., of the polyimide film, meet 0<B/A<2.

Abstract: The present invention provides a display substrate polyimide film having: remarkably improved insulation characteristics; inner pores, included in the polyimide film, of which the maximum size is 10 nm or less; and a high maximum dielectric breakdown voltage of 350 V/?m or more. The polyimide film according to the present invention has improved insulation characteristics so as to be capable of suppressing the generation of a current fluctuation of TFTs according to the long-term driving of a TFT device in a display such as an OLED, thereby enabling the deterioration of the contrast of a display to be reduced.

Abstract: The present invention provides a display substrate polyimide film having: remarkably improved insulation characteristics; inner pores, included in the polyimide film, of which the maximum size is 10 nm or less; and a high maximum dielectric breakdown voltage of 350 V/?m or more. The polyimide film according to the present invention has improved insulation characteristics so as to be capable of suppressing the generation of a current fluctuation of TFTs according to the long-term driving of a TFT device in a display such as an OLED, thereby enabling the deterioration of the contrast of a display to be reduced.

Abstract: A polyimide film according to the present invention can be effectively used as a substrate for a flexible display device without a deterioration in heat resistance even at a temperature of 350° C. or higher since a coefficient of thermal expansion (A) in the section of 100-350° C., of the polyimide film, and a coefficient of thermal expansion (B) in the section of 350-450° C.

Abstract: The present invention can provide a method for manufacturing a polyimide with improved thermal stability that has no contraction even at a high temperature, by adjusting the amount of an acid anhydride in the preparation of a polyimide precursor, and a polyimide film manufactured by the method causes residual stress in a substrate during a high-temperature thermal treatment procedure, thereby suppressing the occurrence of problems, such as cracks in an inorganic film or delamination of a film.