Display device

1. A display device comprising:

a first base material;

a second base material;

an optical layer placed between the first base material and the second base material;

a first retardation layer placed in contact with the first base material;

the first base material comprises a polyimide; and

the first retardation layer includes a first liquid crystal layer which is vertically aligned,

wherein the first base material has a retardation of not more than 150 nm per 1 μm in the thickness direction, and

the first retardation layer has a retardation of not less than 60 nm per 1 μm in the thickness direction.

2. The display device according to claim 1 , further comprising a second retardation layer placed in contact with the second base material,

the second base material comprises a polyimide, and

the second retardation layer includes a second liquid crystal layer which is vertically aligned.

3. The display device according to claim 2 , wherein a transistor is placed between the first base material and the optical layer, and

the second retardation layer is placed on a surface on an opposite side to a surface on which the second base material faces the optical layer.

4. The display device according to claim 2 , wherein the second base material has a retardation of not more than 150 nm per 1 μm in a thickness direction, and

the second retardation layer has a retardation of not less than 60 nm per 1 μm in the thickness direction.

5. The display device according to claim 1 , wherein a transistor is placed between the first base material and the optical layer, and

the first retardation layer is placed on a surface on an opposite side to a surface on which the transistor of the first base material is placed.

6. The display device according to claim 3 , wherein the second base material has a retardation of not more than 150 nm per 1 μm in a thickness direction, and

the second retardation layer has a retardation of not less than 60 nm per 1 μm in the thickness direction.

7. The display device according to claim 2 , wherein the polyimide of the second base material includes a functional group having a vertical orientation.

8. The display device according to claim 1 , wherein the first liquid crystal layer is polymerized by a polymerizable group which is cured with ultraviolet light.

9. The display device according to claim 2 , wherein the second liquid crystal layer is polymerized by a polymerizable group which is cured with ultraviolet light.

10. The display device according to claim 2 , wherein the first base material and the second base material have flexibility.

11. The display device according to claim 1 , wherein the optical layer comprises a third liquid crystal layer, an aligning film containing a polyimide is placed on a surface of the first base material which is in contact with the third liquid crystal layer, and

a thickness of the first base material is larger than a thickness of the aligning film.

12. A display device comprising:

a first base material;

a second base material;

an optical layer placed between the first base material and the second base material;

a first retardation layer placed in contact with the first base material;

the first base material comprises a polyimide; and

the first retardation layer includes a first liquid crystal layer which is vertically aligned,

wherein the polyimide of the first base material includes a functional group having a vertical orientation.

13. The display device according to claim 12 , further comprising a second retardation layer placed in contact with the second base material,

the second base material comprises a polyimide, and

the second retardation layer includes a second liquid crystal layer which is vertically aligned.

14. The display device according to claim 13 , wherein a transistor is placed between the first base material and the optical layer, and

the second retardation layer is placed on a surface on an opposite side to a surface on which the second base material faces the optical layer.

15. The display device according to claim 12 , wherein the second base material has a retardation of not more than 150 nm per 1 μm in a thickness direction, and

the second retardation layer has a retardation of not less than 60 nm per 1 μm in the thickness direction.

16. The display device according to claim 12 , wherein a transistor is placed between the first base material and the optical layer, and

the first retardation layer is placed on a surface on an opposite side to a surface on which the transistor of the first base material is placed.

17. The display device according to claim 14 , wherein the second base material has a retardation of not more than 150 nm per 1 μm in a thickness direction, and

the second retardation layer has a retardation of not less than 60 nm per 1 μm in the thickness direction.

18. The display device according to claim 12 , wherein the first liquid crystal layer is polymerized by a polymerizable group which is cured with ultraviolet light.

19. The display device according to claim 12 , wherein the optical layer comprises a third liquid crystal layer, an aligning film containing a polyimide is placed on a surface of the first base material which is in contact with the third liquid crystal layer, and

a thickness of the first base material is larger than a thickness of the aligning film.