Flexible substrate, preparation method thereof, and display device
Disclosed are a flexible substrate, a preparation method thereof, and a display device, to improve the encapsulation effect and the product yield. The flexible substrate includes: a base substrate, where the base substrate has a plurality of sub-pixel areas arranged in an array, connection areas each for connecting adjacent sub-pixel areas; and hollow areas among the sub-pixel areas and the connection area; in each sub-pixel area, there are a pixel circuit, an isolation structure surrounding the pixel circuit, and a light-emitting functional layer covering the pixel circuit and the isolation structure; the isolation structure has a hollow pattern at a junction of the sub-pixel area and the connection area; the connection area has a signal line therein, and the signal line is electrically connected with the pixel circuit through the hollow pattern; and the isolation structure has an undercut that interrupts the light-emitting functional layer.
1. A flexible substrate, comprising:
a base substrate;
wherein the base substrate comprises:
a plurality of sub-pixel areas arranged in an array;
connection areas between the sub-pixel areas, wherein each of the connection areas connects adjacent sub-pixel areas; and
hollow areas among the sub-pixel areas and the connection area;
wherein in each sub-pixel area, a pixel circuit, an isolation structure surrounding the pixel circuit, and a light-emitting functional layer covering the pixel circuit and the isolation structure are provided;
wherein the isolation structure has a hollow pattern at a junction of a sub-pixel area and a connection area; each of the connection areas is provided with a signal line therein, wherein the signal line is electrically connected with the pixel circuit through the hollow pattern; and
the isolation structure has an undercut that interrupts the light-emitting functional layer.
2. The flexible substrate according to claim 1 , wherein the undercut comprises a first undercut on a side of the isolation structure facing the pixel circuit, and/or a second undercut on a side of the isolation structure facing away from the pixel circuit.
3. The flexible substrate according to claim 2 , wherein the isolation structure comprises a plurality of film layers disposed in stack, wherein a width of at least part of an intermediate film layer is smaller than that of an upper film layer.
4. The flexible substrate according to claim 3 , wherein the isolation structure comprises a multi-layer metal layer and a transparent conductive layer disposed in stack successively, wherein a width of an intermediate layer of the multi-layer metal layer is smallest.
5. The flexible substrate according to claim 4 , wherein the multi-layer metal layer is disposed in a same layer as a source and a drain of a thin film transistor in the pixel circuit, and the transparent conductive layer is disposed in a same layer as an anode in the pixel circuit.
6. The flexible substrate according to claim 5 , wherein the multi-layer metal layer is a titanium/aluminum/titanium stacked layer.
7. The flexible substrate according to claim 5 , wherein the transparent conductive layer is an indium tin oxide/silver/indium tin oxide stacked layer.
8. The flexible substrate according to claim 1 , wherein the light-emitting functional layer comprises a light-emitting layer and a cathode disposed on the light-emitting layer, and the undercut interrupts the cathode.
9. The flexible substrate according to claim 8 , wherein a material of the cathode is a magnesium-silver alloy.
10. A display device comprising the flexible substrate according to claim 1 .
11. A preparation method of a flexible substrate, comprising:
providing a base substrate;
wherein the base substrate comprises:
a plurality of sub-pixel areas arranged in an array;
connection areas between the sub-pixel areas, wherein each of the connection areas connects adjacent sub-pixel areas; and
hollow areas among the sub-pixel areas and the connection area
forming, in each of the sub-pixel areas, a pixel circuit and an isolation structure surrounding the pixel circuit;
forming, in each of the connection areas, a signal line connecting with the pixel circuit; and
forming a light-emitting functional layer covering the pixel circuit and the isolation structure,
wherein the isolation structure has a hollow pattern at a junction of the sub-pixel area and the connection area; the signal line in the connection area is electrically connected with the pixel circuit through the hollow pattern; and the isolation structure has an undercut that interrupts the light-emitting functional layer.
12. The method according to claim 11 , wherein said that forming a pixel circuit and an isolation structure surrounding the pixel circuit in each of the sub-pixel areas comprises:
forming film layers of a thin film transistor successively on the base substrate, wherein a multi-layer metal layer covering an encapsulation area is formed at a same time as formation of a source and drain metal layer of the thin film transistor;
forming an anode layer on the thin film transistor and the multi-layer metal layer;
forming a pattern of an anode on the thin film transistor and forming a pattern of a transparent conductive layer on the multi-layer metal layer, by using a patterning process;
forming a pattern of a multi-layer metal layer by using a patterning process, wherein on the base substrate, a projection of the pattern of the transparent conductive layer coincides with a projection of the pattern of the multi-layer metal layer; and
forming an undercut on a side of the multi-layer metal layer facing the pixel circuit, and/or on a side of the multi-layer metal layer facing away from the pixel circuit.
13. The method according to claim 12 , wherein said that forming a pattern of an anode on the thin film transistor and forming a pattern of a transparent conductive layer on the multi-layer metal layer by using a patterning process comprises:
forming the pattern of the anode on the thin film transistor and forming the pattern of the transparent conductive layer on the multi-layer metal layer by using a wet etching process; and
wherein said that forming the pattern of the multi-layer metal layer by using a patterning process comprises:
forming the pattern of the multi-layer metal layer by using a dry etching process.
14. The method according to claim 12 , wherein said that forming an undercut on the side of the multi-layer metal layer facing the pixel circuit, and/or on the side of the multi-layer metal layer facing away from the pixel circuit comprises:
etching an intermediate layer of the multi-layer metal layer by a wet etching process, to form an undercut on the side of the multi-layer metal layer facing the pixel circuit, and/or on the side of the multi-layer metal layer facing away from the pixel circuit.
15. The method of claim 11 , wherein the light-emitting functional layer comprises a light-emitting layer and a cathode disposed on the light-emitting layer; and said that forming a light-emitting functional layer covering the pixel circuit and the isolation structure comprises:
forming the light-emitting layer on the pixel circuit; and
forming the cathode covering the light-emitting layer and the isolation structure, wherein the undercut interrupts the cathode.