Display device and method for bonding the same

1. A method for bonding a display device, the method comprising:

disposing a display substrate, comprising a central portion and an edge portion adjacent to the central portion, on a pad disposed on a stage;

forming a lubrication layer on the display substrate;

forming an adhesive layer on the lubrication layer;

providing a window substrate comprising a planar portion and a bending portion that is bent from the planar portion;

aligning the window substrate with the display substrate;

attaching the adhesive layer to the window substrate; and

applying heat to the adhesive layer,

wherein viscosity of the adhesive layer increases during a first period for which a temperature of the adhesive layer increases from a first temperature to a second temperature.

2. The method of claim 1 , wherein the central portion is pressed through the pad disposed between the display substrate and the stage.

3. The method of claim 2 , further comprising ejecting air through a plurality of openings defined in a top surface of the stage,

wherein the edge portion is pressed through an elastic film, which at least partially surrounds the pad and the openings, is disposed between the stage and the display substrate, and is expanded by the ejected air.

4. The method of claim 2 , wherein the edge portion is pressed through a roller disposed on the stage so as to be adjacent to the pad.

5. The method of claim 1 , wherein the lubrication layer is absorbed to the adhesive layer after a predetermined period of time.

6. The method of claim 5 , wherein the predetermined period of time is before a time at which the heat is applied to the adhesive layer.

7. The method of claim 1 , further comprising pressing the display substrate through the pad disposed between the display substrate and the stage,

wherein the pressing of the display substrate through the pad comprises:

pressing the display substrate through the pad;

pressing the display substrate at a first intensity for the first period; and

pressing the display substrate at a second intensity greater than the first intensity for a second period after the first period.

8. The method of claim 7 , wherein viscosity intensity of the adhesive layer increases from the first intensity to the second intensity.

9. The method of claim 1 , wherein a viscosity intensity of the adhesive layer ranges from 1 gf/inch to 30 gf/inch at the first temperature, and from 300 gf/inch to 3,000 gf/inch at the second temperature.

10. The method of claim 1 , further comprising forming an auxiliary lubrication layer on a rear surface of the window substrate facing the display substrate.

11. A method for bonding a display device, the method comprising:

providing a window substrate comprising a planar portion and a bending portion that is bent from the planar portion;

forming a first lubrication layer on a rear surface of the window substrate;

disposing a display substrate, comprising a central portion and an edge portion adjacent to the central portion, on a pad disposed on a stage;

forming an adhesive member, comprising an adhesive layer and a second lubrication layer, on the display substrate;

attaching the central portion to the planar portion; and

attaching the edge portion to the bending portion,

wherein the first lubrication layer formed on the window substrate comes into direct contact with the adhesive member.

12. The method of claim 11 , wherein the first lubrication layer is absorbed by the window substrate or partially evaporated by heat after the display substrate is attached to the window substrate.

13. The method of claim 11 , wherein the first lubrication layer is formed only on the bending portion of the window substrate and not on the planar portion.

14. The method of claim 11 , wherein a viscosity of the adhesive layer increases during a period for which a temperature of the adhesive layer is increases.