BACKGROUND OF INVENTION

Field of Invention

The present invention relates to a field of display technologies, and in particular, to a display panel and a display device.

Description of Prior Art

As a new generation of display products, a flexible display device has attracted more and more attention because of its advantages of ultra-lightness, ultra-thinness, high definition, fast response times, flexibility, and portability. A flexible display panel of the flexible display device adopts a soft and flexible plastic substrate, which is very suitable for manufacture of the display device having a narrow bezel. This is because a peripheral area of the flexible display panel can be bent or folded to be disposed on a side or a bottom of a screen, thereby reducing a proportion of the non-display area in the front area, and achieving a narrow bezel design. For example, the flexible display panel can adopt a chip on panel (COP) process, and a metal trace in the peripheral area (the metal traces connecting gate driver on array (GOA) or an active display area (AA) to a driving chip) can be directly fabricated on the flexible substrate by using an array process, and the flexible circuit board can be omitted. As such, by designing a bending region, the metal traces and the driving chip in the peripheral area can be folded to the side or bottom the display area to realize the narrow bezel design.

Referring toFIGS. 1A-1C,FIG. 1Ais a top view of the flexible display device,FIG. 1Bis a cross-sectional view of the flexible display device shown inFIG. 1Awhen it is bent, andFIG. 1Cis a cross-sectional view of film structure in the bending region along the line AA′ ofFIG. 1A. The flexible display panel of the flexible display device includes a display area11and a non-display area12which is bendable at the periphery of the display area11. The non-display area12includes a driving chip area121, a peripheral trace area123, and a bending region122between the peripheral trace areas123and the driving chip area121. The peripheral trace area123is connected to the display area11(or the GOA area) and the driving chip1211of the driving chip area121by a metal trace. The peripheral trace region123and the driving chip region121are folded at the bending region122to the side or bottom of the display region11, as shown inFIG. 1B, to realize a narrow bezel design.

As shown inFIG. 1C, the bending region122includes a flexible substrate101, a first organic layer102, a metal trace103, a second organic layer104, a third organic layer105, and a fourth organic layer106which are sequentially stacked. As can be seen from the film structure shown inFIG. 1C, the metal trace103is located between the stacked films. Since the flexible substrate101has a greater thickness and a larger Young's modulus, a stress neutral surface is generally located in the substrate material, and the metal trace103is located above the neutral surface. Examples of typical values of the Young's modulus and Poisson's ratio of the bending region involving the film materials are shown in Table 1 below. The flexible display needs to be rolled up or bent during use, even frequently bent, such that, when it is bent, the metal trace103is subjected to a large stress, and cracks or breaks are easily generated, resulting in an increase in the resistance of the metal trace103, or even breakage, causing a display anomalies.

TABLE 1Examples of typical values of the Young's modulus and Poisson'sratio of the film materials of the bending region.MaterialYoung Modulus (Mpa)Poisson's ratioPET film40000.35planarization layer34000.30flexible substrate- polyimide92000.35Al710000.33Ti1020000.30amorphous silica731000.17amorphous silicon nitride2260000.288

Therefore, how to effectively adjust the stress neutral surface, reduce the stress of the metal trace when it is bent, reduce the probability of breakage of the metal trace when the flexible display is bent, and reduce the risk of failure of the metal trace, are urgent problems that need to be solved in developments of the flexible display, narrow bezel, or bezel free technology.

SUMMARY OF INVENTION

An object of the present invention is to provide a display panel and a display device to solve the problems that the existing display panel has a large stress on a metal trace when it is bent, and crack or breakage are easily generated. By adjusting the stress neutral surface, the stress of the metal trace is reduced when it is bent, thus reducing the probability of breakage of the metal trace when the flexible display is bent, and reducing the risk of failure of the metal trace.

To achieve the above object, the present invention provides a display panel including a bending region, the bending region including a flexible substrate, wherein the bending region further includes: a first metal trace and at least one stress adjustment layer above the flexible substrate, the stress adjustment layer including a plurality of patterned structures spaced apart from each other, each of the patterned structures being a polygon or having at least one side of an arc, the plurality of patterned structures being arranged in a plurality of rows, and at least two rows of the patterned structures being non-aligned in a second direction, wherein

a direction of the first metal trace is defined as a first direction, a direction perpendicular to the direction of the first row is defined as the second direction, and the patterned structures of the stress adjustment layer arranged along the first direction are defined as a row of the patterned structures.

To achieve the above object, the present invention also provides a display panel including a bending region, the bending region including a flexible substrate, wherein the bending region further includes: a first metal trace and at least one stress adjustment layer above the flexible substrate, and the stress adjustment layer includes a plurality of patterned structures spaced apart from each other.

To achieve the above object, the present invention also provides a display device including a display panel, the display panel including a bending region, the bending region including a flexible substrate; wherein the bending region further includes: a first metal trace and at least one stress adjustment layer above the flexible substrate, and the stress adjustment layer includes a plurality of patterned structures spaced apart from each other.

The present invention has the advantages that: by adding a stress adjustment layer having a plurality of pattern structures spaced apart from each other, the display panel of the present invention can adjust the stress neutral surface, reduce the stress of the metal trace when it is bent, avoid or mitigate excessive stress causing generation and expansion of cracks in the stress adjustment layer, thereby reducing the probability of breakage of the metal trace when the flexible display is bent, thus reducing the risk of failure of the metal trace.

