CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority from Chinese patent application No. 201910814248.4 filed to China National Intellectual Property Administration (CNIPA) on Aug. 30, 2019, the disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to the field of display technologies, and particularly relates to an optical adhesive layer, a stretchable display device and a preparing method for an optical adhesive layer.

BACKGROUND

Organic light-emitting diodes (OLEDs) are considered to be one of the most promising display devices because of their advantages of wide viewing angle, simple processing technology, low power consumption, fast response, high light-emitting efficiency, thinness, small volume, wide temperature range, energy saving, environmental protection, capability of realizing flexible display, and the like.

Recently, to implement stretchable display, the OLED display has been prepared by forming a substrate with a flexible or elastic material. In current stretchable display devices, the substrate of the flexible or elastic material is typically designed to have a stretchable structure so that a certain stretching ratio can be achieved by stretching a hollow-out region by means of island (display unit) and bridge (circuit connection unit) connection.

In current stretchable display devices, in order to protect the flexible display substrate, a backing film is typically attached under a flexible TFT backplane for protection, and the two parts are adhered together by an Optical Clear Adhesive (OCA) Layer. However, in the stretchable display device based on this structure, when the display device is stretched, the deformation region and stress of the stretchable display device are mainly concentrated on the stretched edge, while the tension force and deformation inside the display device are very small, finally resulting in that the edge has excessive deformation and even is broken, while no stretching and deformation occurs inside the display screen, and thus leading to a very low stretching ratio in general. The main reason for this phenomenon is that the TFT backplane layer of the display substrate made of a PI material has the greatest elastic modulus, the backing film material has a medium elastic modulus, and the Optical Clear Adhesive (OCA) layer between the two has the smallest elastic modulus, i.e. has the highest flexibility and is most likely to be deformed. As a result, the OCA is deformed greatly in the stretched region and even rubbed, while the OCA inside the screen is not even stretched, thereby causing the problem that the patterned PI layer on the OCA layer is broken due to excessive local stress on the edge region, while no obvious stretching occurs in the interior.

SUMMARY

In an embodiment of the present disclosure, there is provided an optical adhesive layer, including:

an edge region enclosing a hollow portion;

a plurality of block regions distributed in the hollow portion along a first direction and a second direction; and

connection ribs connecting the block regions to the edge region, wherein the connection ribs are distributed in the hollow portion in a net form.

Optionally, in the optical adhesive layer, end faces of the edge region and the block region facing a third direction are both located in a first plane, and an end face of the connection rib facing the third direction is located in a second plane,

wherein the first plane protrudes from the second plane, and the third direction is perpendicular to the first direction and the second direction.

Optionally, in the optical adhesive layer, end faces of the edge region, the block region and the connection rib facing a fourth direction are all located in a third plane;

wherein the fourth direction is opposite to the third direction.

Optionally, in the optical adhesive layer, a distance between the second plane and the third plane is in the range of ½ to ⅘ of a distance between the first plane and the third plane.

Optionally, in the optical adhesive layer, the connection ribs include:

a plurality of first ribs disposed along the first direction, and a plurality of second ribs disposed along the second direction; wherein both ends of each of the first ribs and both ends of each of the second ribs are connected to the edge region, respectively, a plurality of the first ribs are intersected with a plurality of the second ribs to form a plurality of quadrilateral regions, wherein each of the quadrilateral regions is provided with a corresponding one of the block regions; and

third ribs disposed in each of the quadrilateral regions for connecting the block regions with the first ribs and the second ribs that form the quadrilateral regions.

Optionally, in the optical adhesive layer, the third ribs connect the block region and the second ribs along the first direction, and connect the block region and the first ribs along the second direction.

Optionally, in the optical adhesive layer, at least a part of the third ribs extend to connect with the edge region in the quadrilateral region adjacent to the edge region.

Optionally, in the optical adhesive layer, the first rib, the second rib and the third rib each have a quadrilateral cross section, and a cross section width of the third rib is smaller than or equal to that of the first rib or the second rib.

Optionally, in the optical adhesive layer, the block region has a viscosity higher than the connection rib.

Optionally, in the optical adhesive layer, a cover material layer having a viscosity lower than the block region is provided on the end face of the connection rib facing the third direction.

In an embodiment of the present disclosure, there is further provided a stretchable display device, including any one of the optical adhesive layers as described above.

Optionally, in the stretchable display device, the stretchable display device further includes a display substrate and a backing film layer; and the optical adhesive layer connects the display substrate and the backing film layer;

wherein the display substrate includes a plurality of islands distributed at intervals and each provided with a pixel unit; and the islands are attached to the block regions in a one-to-one correspondence manner.

Optionally, in the stretchable display device, an orthographic projection of the block region on the island is located within the island.

Optionally, in the stretchable display device, the display substrate further includes connection regions connecting the plurality of islands, wherein an orthographic projection of each connection region in a plane of the optical adhesive layer is located on the connection rib, and a gap is present between the connection region and the connection rib.

In an embodiment of the present disclosure, there is further provided a preparing method for any one of the optical adhesive layers as described above, wherein the method includes:

preparing the optical adhesive layer by a printing process; or

providing a film body with a preset thickness, and patterning the film body to form the optical adhesive layer.

Optionally, in the preparing method, the step of patterning the film body to form the optical adhesive layer includes:

patterning the film body by irradiating with UV light to form the optical adhesive layer.

