Back film and flexible display panel

Abstract

The invention provides a back film and a flexible display panel. The back film comprises a substrate, the substrate is provided with a bendable area, and the bendable area is provided with a pluralityof open units; and every open unit comprise a plurality of first open units, and openings of the first open units are nonlinear in the bending axis direction of the bendable area. The bendable area of the back film of the flexible display panel is provided with the plurality of open units, so it is guaranteed that the back film has a good elasticity and can be bent and folded, the possibility ofpermanent deformation or breakage of a connecting portion between the adjacent first open units is minimized, the reliability is improved, and the bending stress of the back film can be reduced without increasing the opening area.

Description

technical field [0001] The invention relates to the field of display technology, in particular to a back film and a flexible display panel. Background technique [0002] In recent years, flexible OLED displays have become more and more recognized and liked by consumers. Flexible displays have obvious advantages over traditional displays, such as: color saturation, flexibility and deformability, etc. Flexible display devices have been commercialized and will develop into more complex and advanced forms in the future. Flexible display devices can be realized in various forms, such as bendable display devices, foldable display devices and rollable display devices. [0003] The flexible display panel of the flexible display device can be bent or unbent (flattened) under the action of external force as required. As the bending radius of the panel becomes smaller, in order to facilitate the bending or unbending operation without degrading the performance of the flexible display p...

AI Technical Summary

Problems solved by technology

[0004] The traditional flexible display panel uses a plastic back film with a thickness of about 100 microns. After being bent many times, it is prone to plastic deformation, recovery is difficult, and the unfolding characteristics deteriorate, resulting in downward plastic deformation of the center part and upward plastic deformation of the two wing parts. question

Thinning of the plastic back film can reduce the problem of deformation, but the elastic recovery is reduced, and there are problems with the support. Therefore, a material with a Young's modulus greater than 50Gpa is usually required to solve the contradiction of the decrease in elasticity after the thickness is reduced. Therefore, stainless steel SUS material becomes a good choice. choose

[0005] Therefore, in the prior art, using stainless steel SUS as the back film of the folding display device provides support while ensuring the bending resistance of the folding display product, which has obvious advantages different from the plastic back film, but the elastic modulus of stainless steel SUS Generally, it is very large and not easy to bend, so it is necessary to carry out patterned hollowing in the bendable area to disperse the stress generated by the stainless steel SUS during bending, so that the SUS is easy to deform while maintaining the elastic recovery force, and solves the problem that the stainless steel SUS can be bent. However, at present, the hollow pattern of the bendable area on the stainless steel SUS back film is designed vertically. The opening of the hollow pattern is a straight line extending along the direction of the bending axis of the bendable area. The connecting part between the openings is the force point of the bending stress, and the connecting part between the openings is symmetrical along the axis, so its force is a transverse tensile stress. As the number of bendings increases, the openings will be irreversibly deformed by the transverse tensile stress. It reduces the reliability of the flexible display device, which is not conducive to the long-term use of folding products

For this problem of opening expansion, it can be solved by designing a larger opening. Such a structure will suffer less stress and have better elasticity, but the increase in opening will reduce the rigidity of the backplane in the folding area, making it difficult to ensure the predetermined rigidity of the support. , so how to solve the contradiction of effectively reducing the stress without expanding the opening area becomes the focus

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