Display back plate and display device

1. A display back plate, including a display area and a non-display area surrounding the display area, wherein the non-display area is provided with at least one circle of a first cofferdam surrounding the display area, a first thin film encapsulation layer is arranged on the first cofferdam, and the non-display area is provided with a fan-out area, a second cofferdam is arranged on one side of the first cofferdam close to the fan-out area, the second cofferdam is provided with a first bonding pattern including a plurality of protrusions, and the first thin film encapsulation layer at least partially covers the plurality of protrusions.

2. The display back plate of claim 1 , wherein the first bonding pattern includes first strip-shaped protrusions or first block-shaped protrusions.

3. The display back plate of claim 1 , wherein at least a portion of the first cofferdam close to the fan-out area is provided with a second bonding pattern bonded to the first thin film encapsulation layer, and the second bonding pattern includes a plurality of protrusions.

4. The display back plate of claim 3 , wherein the second bonding pattern includes second strip-shaped protrusions or second block-shaped protrusions.

5. The display back plate of claim 1 , wherein, the second cofferdam has a first area and a second area, the first thin film encapsulation layer covers the first area, the second area is not covered by the first thin film encapsulation layer, and a second thin film encapsulation layer covers the second area and at least partially covers an edge of the first thin film encapsulation layer located at the first area.

6. The display back plate of claim 1 , wherein the non-display area is provided with two circles of the first cofferdam located at an inner side and an outer side at intervals, and the second cofferdam is provided outside a circle of the first cofferdam located at the outer side.

7. The display back plate of claim 3 , wherein the non-display area is provided with two circles of the first cofferdam located at an inner side and an outer side at intervals, and a side of each circle of the first cofferdam facing the first thin film encapsulation layer has the second bonding pattern.

8. The display back plate of claim 1 , wherein the first cofferdam and the second cofferdam are disposed in a same layer.

9. The display back plate of claim 6 , wherein the second cofferdam and the circle of the first cofferdam located at the outer side are integrally arranged.

10. The display back plate of claim 1 , wherein the first bonding pattern includes at least one of frustum-shaped protrusions, strip-shaped protrusions with an arc-shaped cross section, and strip-shaped protrusions with a trapezoidal cross section.

11. The display back plate of claim 3 , wherein the second bonding pattern includes at least one of frustum-shaped protrusions, strip-shaped protrusions with an arc-shaped cross section, and strip-shaped protrusions with a trapezoidal cross section.

12. The display back plate of claim 1 , wherein a material of the first cofferdam and the second cofferdam is a photosensitive resin.

13. A display device, including a display back plate, including a display area and a non-display area surrounding the display area, wherein the non-display area is provided with at least one circle of a first cofferdam surrounding the display area, a first thin film encapsulation layer is arranged on the first cofferdam, and the non-display area is provided with a fan-out area, a second cofferdam is arranged on one side of the first cofferdam close to the fan-out area, the second cofferdam is provided with a first bonding pattern including a plurality of protrusions, and the first thin film encapsulation layer at least partially covers the plurality of protrusions.