It can be understood that for the convenience of verification, the thickness of the backplate 20 and the thickness of the polarizer sheet 30 in FIG. 3, FIG. 4, and FIG. 5 provided by the embodiments of the present invention are all the thicknesses of entire surfaces of the backplate 20 and the polarizer sheet 30, but an verification area is the corner curved-surface sub-region 1022 of the display panel.

Wherein, it can be obtained from FIG. 3 that a maximum wrinkle amplitude of the display panel is 0.074 mm, it can be obtained from FIG. 4 that a maximum wrinkle amplitude of the display panel is 0.064 mm, and it can be obtained from FIG. 5 that a maximum wrinkle amplitude of the display panel is 0.052 mm. Wherein, a maximum wrinkle amplitude represents a maximum distance between a crest and a trough of a wrinkle waveform, i.e., the smaller the maximum wrinkle amplitude is, the less the extent of the wrinkles generated in the display panel is. From the above, it can be understood that with increment of the thickness of the backplate 20, the maximum wrinkle amplitude of the wrinkles generated in the display panel is decreasing, i.e., the extent of the wrinkles generated in the display panel is decreasing. Furthermore, compared the characterization results of the extent of the wrinkle generated in the display panel in FIG. 5 with the characterization results of the extents of the wrinkle generated in the display panel in FIG. 3 and FIG. 4, it can be understood that the maximum wrinkle amplitude of the display panel decreases to a greater extent when the thickness of the backplate 20 is greater than the thickness of the polarizer sheet 30. Therefore, it can be proved that in the embodiments of the present invention, by increasing the thickness of the backplate 20 and configuring the thickness of the backplate 20 to be greater than the thickness of the polarizer sheet 30, the extent of the wrinkles generated in the display panel in the corner curved-surface sub-region 1022 can be effectively lowered, the yield of the display panel can be improved, and display effect of the curved surface of the display panel can be improved.

The film layer structure of the display panel provided by the present invention is described in detail below in combined with specific embodiments.

In one embodiment of the present invention, please refer to FIG. 6 and FIG. 7, and FIG. 6 can be a schematic diagram of a sectional structure along line AA in FIG. 7. In this embodiment, at least in the corner curved-surface sub-region 1022, the thickness of the backplate 20 is greater than the thickness of the polarizer sheet 30. That is, in the embodiment of the present invention, the thickness of the backplate 20 is at least increased in the corner curved-surface sub-region 1022, so that it is made to be greater than the thickness of the polarizer sheet 30.

In one embodiment of the present invention, in the corner curved-surface sub-region 1022, at least part of the display panel is curved in a form of a Gaussian curve surface, and a compression rate of the display panel curved in the form of the Gaussian curve surface is greater than or equal to 0.2. That is, each of the film layers attached in the at least part of the display panel in the corner curved-surface sub-region 1022 is curved in the form of the Gaussian curved surface, and a bending curvature of the film layers is relatively large. The film layers specifically include the backplate 20, the panel main body 10, the polarizer sheet 30, and the adhesive layer 41. In the prior art, the backplate 20, the panel main body 10, the polarizer sheet 30, and the adhesive layer 41 in the display panel need to be attached to the cover plate 50 curved in the form of the Gaussian curved surface at corners. However, the curved surface areas of the backplate 20, the panel main body 10, the polarizer sheet 30, and the adhesive layer 41 at the corners are relatively large and are larger than the curved surface area of the cover plate 50 located at the corners, so that the wrinkles are easily generated, resulting in stress concentration, easily causing encapsulation failure, and generating the problem of dark spots. However, in the embodiments of the present invention, the thickness of the backplate 20 located in the corner curved-surface sub-region 1022 can be increased, which is greater than the thickness of the polarizer sheet 30, so as to increase the thickness of the backplate 20 located in the corner curved-surface sub-region 1022 to increase the stress threshold of generation of the wrinkles in the display panel. Therefore, the backplate 20 is made to be more easily bent into the Gaussian curved surface in the corner curved-surface sub-region 1022, and the probability of wrinkles generated in display panels is lowered. In this way, the display panel is allowed to be more easily bent into the Gaussian curved surface in the corner curved-surface sub-region 1022, so as to improve the yield of the display panel and the display effect in the corner curved-surface sub-region 1022, and to improve the display effect of the curved surface of the display panel.

Additionally, in one embodiment of the present invention, the thickness of the backplate 20 is thickened in the corner curved-surface sub-region 1022, i.e., the backplate 20 includes a backplate body 21 and a thickened portion 22 disposed on the backplate body 21, and the thickened portion 22 is located in the corner curved-surface sub-region 1022.

In this embodiment, the thickened portion 22 is disposed on a side of the backplate body 21 close to the panel main body 10, and a thickness of the thickened portion 22 is uniform. A thickness of the first adhesive layer 42 in the corner curved-surface sub-region 1022 is less than a thickness of the first adhesive layer 42 out of the corner curved-surface sub-region 1022. That is, the side of the first adhesive layer 42 away from the backplate 20 can be a plane, so as to compensate for a level difference generated by the backplate 20 to improve a bonding yield between the backplate 20 and the panel main body 10.

Furthermore, the backplate body 21 includes a first sub-section 211 disposed in the planar display region 101 and a second sub-section 212 disposed in the corner curved-surface sub-region 1022, and an elasticity modulus of the thickened portion 22 and an elasticity modulus of the second sub-section 212 are both less than the elasticity modulus of the first sub-section 211. Because the thickened portion 22 and the second sub-section 212 are located in the corner curved-surface sub-region 1022, they need to enter the Gaussian surface for bending. Therefore, the elastic modulus of the thickened portion 22 and the second sub-section 212 are configured to be smaller than the elasticity modulus of the first sub-section 211 to improve flexibility of the thickened portion 22 and the second sub-section 212, thereby reducing a bending stress. Moreover, the elasticity modulus of the second sub-section 212 is less than the elasticity modulus of the thickened portion 22. When the display panel is bent, as the second sub-section 212 is located on a bending inner side, the second sub-section 212 suffers more extrusion and bending stress than the thickened portion 22. Therefore, the elastic modulus of the second sub-section 212 is configured to be smaller to further improve the flexibility of the second sub-section 212.

Optionally, the elasticity modulus of the first sub-section 211 can be greater than or equal to 3300 Mpa and less than or equal to 3700 Mpa, and the elasticity modulus of the second sub-section 212 and the elasticity modulus of the thickened portion 22 can be both greater than or equal to 2500 Mpa and less than or equal to 3000 Mpa.

Optionally, a material of the thickened portion 22 is same or different as a material of the backplate body 21, and the material of the thickened portion 22 and the material of the backplate body 21 can both include polyethylene terephthalate or polyimide.

In one embodiment of the present invention, a material of the adhesive layer 41 can include optically clear adhesive (OCA). Furthermore, in one embodiment of the present invention, at least in the corner curved-surface sub-region 1022, the thickness of the adhesive layer 41 is greater than the thickness of the backplate 20. That is, the thickness of the adhesive layer 41 is also increased. In this way, the adhesive layer 41 located in the corner curved-surface sub-region 1022 is increased, so as to increase the stress threshold of wrinkles generated in the display panel, to lower probability of the wrinkles generated in the display panel, and to improve yield of the display panel and display effect in the corner curved-surface sub-region 1022.

Continuing from the above, in the embodiments of the present invention, the thickness of the backplate 20 is made to be greater than the thickness of the polarizer sheet 30 at least in the corner curved-surface sub-region 1022. Therefore, compared to the thickness of the polarizer sheet being generally greater than the thickness of a backplate in the prior art, the thickness of the backplate 20 located in the corner curved-surface sub-region 1022 can be increased. By increasing the thickness of the backplate 20 in the corner curved-surface sub-region 1022, the stress threshold of wrinkles generated in the display panel is increased, and probability of the wrinkles generated in the display panel is reduced, so as to improve yield of the display panel and display effect in the corner curved-surface sub-region 1022.

In another embodiment of the present invention, please refer to FIG. 8. The difference between this embodiment and the previous embodiment is that in the corner curved-surface sub-region 1022, the thickness of the backplate 20 gradually increases along a direction away from the planar display region 101, i.e., the thickness of the thickened portion 22 gradually increases along the direction away from the planar display region 101.

Continuing from the above, in this embodiment, the thickness of the backplate 20 is made to be in a gradually changed trend, which lowers probability of the wrinkles generated in the display panel to improve yield of the display panels and the display effect in corner curved-surface sub-regions 1022, while can also prevent from a poor phenomenon due to stress concentration incurred by sudden change in the thickness of the backplate 20.

In another embodiment of the present invention, please refer to FIG. 9. The difference between this embodiment and the first embodiment is that the thickened portion 22 is disposed on a side of the backplate body 21 away from the panel main body 10.

In this embodiment, the elasticity modulus of the thickened portion 22 and the elasticity modulus of the second sub-section 212 are both less than the elasticity modulus of the first sub-section 211. Because the thickened portion 22 and the second sub-section 212 are located in the corner curved-surface sub-region 1022, they need to enter the Gaussian curved surface for bending. Therefore, the elastic modulus of the thickened portion 22 and the second sub-section 212 are configured to be smaller than the elasticity modulus of the first sub-section 211 to improve flexibility of the thickened portion 22 and the second sub-section 212, thereby reducing a bending stress. Additionally, the elasticity modulus of the thickened portion 22 is further less than the elasticity modulus of the second sub-section 212. When the display panel is bent, as the thickened portion 22 is located on a bending inner side, the thickened portion 22 suffers more extrusion and bending stress than the second sub-section 212. Therefore, the elastic modulus of the thickened portion 22 is configured to be smaller to further improve the flexibility of the thickened portion 22.

Continuing from the above, the thickness of the backplate 20 is made to be greater than the thickness of the polarizer sheet 30 at least in the corner curved-surface sub-region 1022 in the embodiment of the present invention. Therefore, compared to the thickness of the polarizer sheet being generally greater than the thickness of a backplate in the prior art, the thickness of the backplate 20 located in the corner curved-surface sub-region 1022 can be increased. By increasing the thickness of the backplate 20 in the corner curved-surface sub-region 1022, the stress threshold of wrinkles generated in the display panel is increased, and probability of the wrinkles generated in the display panel is reduced, so as to improve yield of the display panel and display effect in the corner curved-surface sub-region 1022.

In another embodiment of the present invention, please refer to FIG. 6, FIG. 7, and FIG. 10. FIG. 10 is a schematic view of a sectional structure along line BB in FIG. 7. The difference between this embodiment and the first embodiment is that at least in the lateral-side curved-surface sub-region 1021 and the corner curved-surface sub-region 1022, the thickness of the backplate 20 is greater than the thickness of the polarizer sheet 30.

It can be understood that the thickness of the backplate 20 in the corner curved-surface sub-region 1022 is greater than the thickness of the backplate 20 in the lateral-side curved-surface sub-region 1021, and the thickness of the backplate 20 in the lateral-side curved-surface sub-region 1021 is greater than the thickness of the backplate 20 in the planar display region 101. That is, in this embodiment, by thickening all the parts of the backplate 20 located in the curved-surface display region 102, the probability of wrinkles generated in the curved-surface display region 102 due to bending is effectively lowered. Furthermore, because the bending curvature of the backplate 20 in the corner curved-surface sub-region 1022 is larger, the thickness of the backplate 20 in the corner curved-surface sub-region 1022 is the largest. Compared to the lateral-side curved-surface sub-region 1021, the probability of the wrinkles generated in the backplate 20 can be further lowered.

Furthermore, the backplate 21 further includes a third sub-section 213 disposed in the lateral-side curved-surface sub-region 1021, and an elasticity modulus of the third sub-section 213 is less than an elasticity modulus of the first sub-section 211, so as to improve the flexibility of the backplate 20 located in the lateral-side curved-surface sub-region 1021 to reduce the bending stress. The elasticity modulus of the third sub-section 213 can be further greater than the elasticity modulus of the second sub-section 212. Because the bending curvature in the corner curved-surface sub-region 1022 is the largest, the elasticity modulus of the third sub-section 213 in this embodiment is the smallest, so as to realize a gradient design of the elastic modulus of the backplate 20 to meet requirements for flexibility in different regions.

In other embodiments of the present invention, within the range of the entire display region, i.e., within the range of the planar display region 101 and the curved-surface display region 102, the thickness of the backplate 20 is greater than the thickness of the polarizer sheet 30, as illustrated in FIG. 1. That is, in this embodiment, the entire backplate 20 is thickened, and the thickness of the backplate 20 in the lateral-side curved-surface sub-region 1021 and the thickness of the backplate 20 in the corner curved-surface sub-region 1022 are equal to the thickness of the backplate 20 in the planar display region 101. In this embodiment, the thickened portion can cover the side of the backplate body close to the panel main body 10 or can cover the side of the backplate body away from the panel main body 10 with its entire surface (not shown in the figure).

In addition, in the situation of the entire backplate 20 being thickened, the thickness of the backplate 20 can also be configured in a gradient manner. That is, the thickness of the backplate 20 in the corner curved-surface sub-region 1022 is greater than the thickness of the backplate 20 in the lateral-side curved-surface sub-region 1021, and the thickness of the backplate 20 in the lateral-side curved-surface sub-region 1021 is greater than the thickness of the backplate 20 in the planar display region 101.

Furthermore, the elastic modulus of the backplate 20 in the curved-surface display region 102 is smaller than the elastic modulus of the backplate 20 in the planar display region 101, and the elastic modulus of the back plate 20 in the corner curved-surface sub-region 1022 is smaller than the elastic modulus of the backplate 20 in the lateral-side curved-surface sub-region 1021, so as to realize a gradient design of the elastic modulus of the backplate 20 to meet requirements for flexibility in different regions.

Continuing from the above, the thicknesses of the backplate 20 in the planar display region 101 and the curved-surface display region are made to be both greater than the thickness of the polarizer sheet 30. That is, the entire backplate 20 is thickened to improve the yield of the display panel and the display effect in the corner curved-surface sub-region 1022, while thickness difference of the backplate 20 is not necessary to be configured, which simplifies manufacturing difficulty and the manufacturing process of the backplate 20.

It should be noted that, in one embodiment of the present invention, as the thicknesses of the backplate 20, the polarizer sheet 30, and the adhesive layer 41 increase, the extent of the wrinkles generated in the corner curved-surface sub-region 1022 of the display panel can be reduced. However, when the thickness of the backplate 20 is too large, a phenomenon of poor attachment of the backplate 20 in the corner curved-surface sub-region 1022 can appear. In addition, since the elastic modulus of the polarizer sheet 30 is relatively large, which is generally about 4000 MPa, so hardness of the polarizer sheet 30 is relatively large. If the thickness of the polarizer sheet 30 is too large, the polarizer sheet 30 cannot be easily bent, then a peeling-off phenomenon can easily occur during the attachment process of the display module 60 and the cover plate 50. Furthermore, when the thickness of the adhesive layer 41 is too large, it is easy to affect light transmission of the display panel and reduces the display effect of the display panel.

Continuing from the above, optionally, at least in the corner curved-surface sub-region 1022, the thickness of the backplate 20 can be greater than or equal to 90 μm and can be less than or equal to 250 μm, the thickness of the polarizer sheet 30 can be greater than or equal to 66 μm and can be less than or equal to 106 μm, and the thickness of the adhesive layer 41 can be greater than or equal to 100 μm and can be less than or equal to 200 μm. Furthermore, in the aforesaid thickness range, the thickness of the backplate 20 is greater than the thickness of the polarizer sheet 30, so as to further lower the extent of the wrinkles generated in the display panel.

Please combine with FIG. 1, FIG. 11, FIG. 12, and FIG. 13. In one embodiment of the present invention, the thicknesses of the backplate 20, the polarizer sheet 30, and the adhesive layer 41 are configured, and the extent of reducing the wrinkles is verified when the backplate 20, the polarizer 30, and the adhesive layer 41 have configured thicknesses in the corner curved-surface sub-region 1022.

Wherein, thickness of the backplate 20 being 150 μm, the thickness of the polarizer sheet 30 being 106 μm, and the thickness of the adhesive layer 41 being 200 μm are taken to satisfy the thickness of the adhesive layer