FLEXIBLE DISPLAY DEVICE, FOLDABLE ELECTRONIC DEVICE INCLUDING THE SAME, AND METHOD OF MANUFACTURING FLEXIBLE DISPLAY DEVICE

• US 20150185782A1
• Filed: 12/18/2014
• Published: 07/02/2015
• Est. Priority Date: 12/30/2013
• Status: Active Grant

• Current Assignee: Samsung Electronics Co. Ltd.
• Original Assignee: Samsung Electronics Co. Ltd.
• Inventors: KIM, Jun-hyung, LEE, Won-ho, SEO, Ho-seong
• Granted Patent: US 10,429,893 B2
• Time in Patent Office: Days
• US Class Current: 1/1
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G06F 1/1616 with folding flat displays, e.g. laptop computers or notebooks having a clamshell configuration, with body parts pivoting to an open position around an axis parallel to the plane they define in closed position
• CPC Class Codes: G06F 1/1643 the display being associated to a digitizer, e.g. laptops that can be used as penpads details related to the relative motion of the display enclosure with respect to the body enclosure, e.g. to move between laptop and tablet PC configuration G06F1/1615
• CPC Class Codes: G06F 1/1652 the display being flexible, e.g. mimicking a sheet of paper, or rollable
• CPC Class Codes: G06F 1/166 related to integrated arrangements for adjusting the position of the main body with respect to the supporting surface, e.g. legs for adjusting the tilt angle
• CPC Class Codes: G06F 1/1679 for locking or maintaining the movable parts of the enclosure in a fixed position, e.g. latching mechanism at the edge of the display in a laptop or for the screen protective cover of a PDA G06F1/1681 takes precedence
• CPC Class Codes: G06F 2203/04102 Flexible digitiser, i.e. constructional details for allowing the whole digitising part of a device to be flexed or rolled like a sheet of paper
• CPC Class Codes: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 77/111 Flexible substrates
• CPC Class Codes: Y02E 10/549 Organic PV cells
• CPC Class Codes: Y02P 70/50 Manufacturing or production processes characterised by the final manufactured product
• CPC Class Codes: Y10T 156/1028 by bending, drawing or stretch forming sheet to assume shape of configured lamina while in contact therewith

Abstract

A flexible display device that may fold so that a neutral surface has a radius of curvature is provided. The flexible display device includes a plurality of panel layers that are sequentially stacked on one another and comprise a display panel layer configured to display an image and a transparent protective panel layer; and adhesive layers that sequentially adhere the plurality of panel layers to one another. An elastic modulus and a thickness of each of the adhesive layers and the plurality of panel layers are determined so that a neutral surface is located on a layer other than the display panel layer.

Claims

1. A flexible display device that is foldable so that a neutral surface has a radius of curvature, the flexible display device comprising:

a plurality of panel layers that are sequentially stacked on one another and comprise a display panel layer configured to display an image and a transparent protective panel layer; and

adhesive layers that sequentially adhere the plurality of panel layers to one another,

wherein an elastic modulus and a thickness of each of the adhesive layers and the plurality of panel layers are determined so that the neutral surface is located on a layer other than the display panel layer.

2. The flexible display device of claim 1, further comprising a touch panel layer that is disposed between the display panel layer and the transparent protective panel layer,

wherein the adhesive layers comprise a first adhesive layer that adheres the touch panel layer to the display panel layer and a second adhesive layer that adheres the touch panel layer to the transparent protective panel layer.

3. The flexible display device of claim 1,

wherein the transparent protective panel layer forms an inner surface layer in a bending state, and

wherein the display panel layer forms an outer surface layer in the bending state.

4. The flexible display device of claim 1, wherein the elastic modulus and the thickness of each of the adhesive layers and the plurality of panel layers are determined so that the neutral surface is located between the display panel layer and the transparent protective panel layer.

5. The flexible display device of claim 1, wherein a position of the neutral surface is determined so that when the flexible display device folds, the transparent protective panel layer and the display panel layer simultaneously reach a yield strain.

6. The flexible display device of claim 1, wherein the elastic modulus and the thickness of each of the adhesive layers and the plurality of panel layers are determined so that when the flexible display device folds, the transparent protective panel layer and the display panel layer simultaneously reach a yield strain.

7. The flexible display device of claim 1,

wherein, when a distance between an outer surface of the display panel layer and each of central planes of the adhesive layers and the plurality of panel layers in a thickness direction is P_i, a distance between the outer surface of the display panel layer and the neutral surface is y_N, a yield strain of the adhesive layers and the plurality of panel layers is ε

_Yi, and a radius of curvature of the flexible display device is r, and

wherein the elastic modulus and the thickness of each of the adhesive layers and the plurality of panel layers are determined to satisfy

8. The flexible display device of claim 7, wherein, when a thickness of each of the adhesive layers and the plurality of panel layers is Ti and a length of a fine air-void of the adhesive layers is L, the elastic modulus and the thickness of each of the adhesive layers and the plurality of panel layers are determined to satisfy

9. The flexible display device of claim 1, wherein a yield strain of the transparent protective layer and the display panel layer is equal to or greater than 0.01.

10. The flexible display device of claim 1, wherein the transparent protective panel layer is plastic-deformed to a radius of curvature that is less than double the radius of curvature and is adhered to another panel layer that is adjacent to the transparent protective panel layer.

17. A foldable electronic device comprising:

first and second bodies that are spaced apart from each other;

a connection unit that is disposed between the first and second bodies and connects the first and second bodies so that the first and second bodies fold/unfold to a radius of curvature; and

a flexible display device of claim 1 that is supported on the first and second bodies across the connection unit.

18. The foldable electronic device of claim 17, wherein, when a distance between an outer surface of the display panel layer and each of central planes of the adhesive layers and the plurality of panel layers in a thickness direction is Pi, a distance between the outer surface of the display panel layer and the neutral surface is y_N, a yield strain of the adhesive layers and the plurality of panel layers is ε

_Yi and a radius of curvature r of the flexible display device satisfies

19. The foldable electronic device of claim 18, wherein, when a thickness of each of the adhesive layers and the plurality of panel layers is Ti and a length of a fine air-void of the adhesive layers is L, the radius of curvature r satisfies

20. The foldable electronic device of claim 17, wherein a yield strain of the transparent protective panel layer and the display panel layer is equal to and greater than 0.01.

21. The foldable electronic device of claim 17, wherein the transparent protective panel layer is plastic-deformed to a radius of curvature that is less than double the radius of curvature and is adhered to another panel layer that is adjacent to the transparent protective panel layer.

22. The foldable electronic device of claim 17, further comprising:

a support member that changes between a first position at which the support member is received in the first body and a second position at which the support member extends to the second body across the connection unit; and

a locking unit that is disposed on the second body and locks the support member that is located at the second position.

23. The foldable electronic device of claim 22, wherein the support member slides between the first and second positions.

24. The foldable electronic device of claim 22, further comprising a locking member that comprises the locking unit, and changes between a third position at which the locking unit locks the support member in a completely unfolded state of the first and second bodies and a fourth position at which the locking unit locks the support member that is located at the second position in a state having an angle between the completely unfolded state and a completely folded state of the first and second bodies.

25. The foldable electronic device of claim 24, wherein the locking member pivots between the third and fourth positions.

11. A method of manufacturing a flexible display device having a multi-layer structure in which a plurality of panel layers are sequentially adhered to one another, the method comprising:

forming a first curvature portion by plastic-deforming a first panel layer; and

adhering the first panel layer to a second panel layer.

12. The method of claim 11, wherein the adhering comprises:

supporting the second panel layer on a jig comprising a second curvature portion that corresponds to the first curvature portion; and

adhering the plastic-deformed first panel layer to the second panel layer.

13. The method of claim 12, wherein the second panel layer is plastic-deformed to comprise the first curvature portion and is supported on the jig.

14. The method of claim 11, wherein the adhering comprises:

supporting the second panel layer on a flat jig; and

elastic-deforming the first panel layer to be spread flat and adhering the elastic-deformed first panel layer to the second panel layer.

15. The method of claim 11,

wherein the second panel layer comprises a display panel layer that displays an image, and

wherein the first panel layer comprises a transparent protective panel layer.

16. The method of claim 11, wherein a radius of curvature of the first curvature portion is equal to or less than double a minimum radius of curvature of the flexible display device.