Flexible display panel, flexible display device, and method for producing flexible display panel
An organic EL element including light emitting layers is formed above a first region of a main surface of a back film. A plurality of terminal portions are formed above a second region of the main surface of the back film. A cover film including an opening is provided as an uppermost layer above the main surface of the back film.
1. A flexible display panel comprising:
a plurality of display elements and a plurality of terminals on a main surface of a flexible substrate, wherein
the main surface of the flexible substrate is divided into a first region including one coupled region and a plurality of second regions separated from each other within the flexible display panel,
the plurality of display elements are above a plurality of display regions as a portion of the first region within the flexible display panel,
the plurality of terminals are above the plurality of second regions,
a flexible film provided as an uppermost layer on the main surface of the flexible substrate includes a plurality of openings,
the plurality of openings are above the plurality of second regions and each of the plurality of openings is surrounded by the flexible film,
a polyimide film containing polyimide resin defines a common layer above the first region and between the flexible substrate and the film defining the plurality of terminals above the plurality of second regions, and
the polyimide film above the plurality of second regions is contracted more than the polyimide film above the first region.
2. The flexible display panel according to claim 1 , wherein
an insulating flattening film including plurality of openings is above the plurality of second regions,
the insulating flattening film includes an organic insulating flattening film or an organic inorganic hybrid insulating flattening film, and
the plurality of openings of the insulating flattening film overlap one layer of a plurality of inorganic layers included in an active element, an inorganic insulating flattening film covering the active element, an inorganic moisture-proof film, and a layer in which the terminals are located in a plan view.
3. The flexible display panel according to claim 2 , wherein
the insulating flattening film is in the plurality of display regions, and
the active element is electrically connected to each of the display elements through an opening of the insulating flattening film in the plurality of display regions.
4. The flexible display panel according to claim 2 , wherein the insulating flattening film is made of a photosensitive material.
5. The flexible display panel according to claim 1 , wherein each of the display elements includes an organic electroluminescence display element.
6. A flexible display device defined by partitioning the flexible display panel according to claim 1 .
7. A method for producing a flexible display panel including a plurality of display elements and a plurality of terminals on a main surface of a flexible substrate, a main surface of a heat-resistant substrate being divided into a first region including one coupled region and a plurality of second regions formed by being separated from each other within the flexible display panel, the method comprising:
a first step of forming a layered film above the first region and the plurality of second regions;
a second step of forming the plurality of display elements on the layered film above a plurality of display regions as a portion of the first region and forming the plurality of terminals on the layered film above the plurality of second regions;
a third step of providing a flexible film including a plurality of openings as an uppermost layer on the main surface of the heat-resistant substrate and each of the plurality of openings is surrounded by the flexible film above the plurality of second regions;
a fourth step of separating the heat-resistant substrate;
a fifth step of bonding the main surface of the flexible substrate to a surface from which the heat-resistant substrate is separated, wherein
a layered film having positive film stress is formed at least above the second region in the first step, and
a polyimide film containing polyimide resin is included in the layered film formed above the first region and the plurality of second regions in the first step,
the heat-resistant substrate is a substrate through which at least portion of a wavelength region of laser beam is transmitted,
the polyimide film is radiated with the laser beam through the heat-resistant substrate and a portion positioned lower than the polyimide film including the heat-resistant substrate is separated in the fourth step, and
a radiation amount of the laser beam to the polyimide film above the plurality of second regions is greater than a radiation amount of the laser beam to the polyimide film above the first region in the fourth step.
8. The method for producing a flexible display panel according to claim 7 , wherein a layered film having positive film stress is formed at least above the second region in the first step.
9. The method for producing a flexible display panel according to claim 7 , wherein the radiation amount of the laser beam to the polyimide film above the plurality of second regions is greater than or equal to 150 mJ/cm 2 and less than or equal to 250 mJ/cm 2 .
10. The method for producing a flexible display panel according claim 7 , wherein the laser beam includes an excimer laser beam or a solid laser beam.
11. A flexible display panel comprising:
a plurality of display elements and a plurality of terminals on a main surface of a flexible substrate, wherein
the main surface of the flexible substrate is divided into a first region including one coupled region and a second region including a plurality of regions separated from each other,
the plurality of display elements are above a display region as a portion of the first region,
the plurality of terminals are above the second region,
a flexible film provided as an uppermost layer on the main surface of the flexible substrate includes an opening,
the opening is above the second region and is surrounded by the flexible film,
a polyimide film containing polyimide resin defines a common layer above the first region and between the flexible substrate and a film forming the plurality of terminals above the second region, and
the polyimide film above the second region is contracted more than the polyimide film above the first region.
12. The flexible display panel according to claim 11 , wherein
an active element electrically connected to each of the plurality of display elements overlaps the display region in a plan view, and
an inorganic insulating film included in the active element or an inorganic insulating flattening film covering the active element does not overlap the second region in the plan view.
13. The flexible display panel according to claim 11 , further comprising:
an inorganic moisture-proof film, wherein the inorganic moisture-proof film does not overlap the second region in a plan view.
14. The flexible display panel according to claim 11 , wherein
an insulating flattening film including an opening is above the second region,
the insulating flattening film includes an organic insulating flattening film or an organic inorganic hybrid insulating flattening film, and
the opening of the insulating flattening film overlaps one layer of a plurality of inorganic layers included in an active element, the inorganic insulating flattening film covering the active element, an inorganic moisture-proof film, and a layer defining the plurality of terminals in a plan view.
15. The flexible display panel according to claim 14 , wherein
the insulating flattening film is in the display region, and
the active element is electrically connected to each of the plurality of display elements through the opening of the insulating flattening film in the display region.
16. The flexible display panel according to claim 11 , wherein each of the plurality of display elements includes an organic electroluminescence display element.
17. A flexible display device defined by partitioning the flexible display panel according to claim 11 .