Flexible Displays

• US 20140042406A1
• Filed: 07/01/2013
• Published: 02/13/2014
• Est. Priority Date: 08/07/2012
• Status: Active Grant

• Current Assignee: Apple Inc.
• Original Assignee: Apple Inc.
• Inventors: Degner, Brett W., Mathew, Dinesh C., Drzaic, Paul S., Grespan, Silvio, Zhong, John Z., Guillou, Jean-Pierre, Sung, Kuo-Hua, Park, Young Bae, Gupta, Vasudha, Chen, Chieh-Wei, Kim, Sang Ha
• Granted Patent: US 9,419,065 B2
• Time in Patent Office: Days
• US Class Current: 257/40
• CPC Class Codes: G02F 1/133305 Flexible substrates, e.g. plastics, organic film
• CPC Class Codes: G02F 1/133388 with constructional differences between the display region and the peripheral region
• CPC Class Codes: H05K 1/028 Bending or folding regions of flexible printed circuits H05K1/0283 takes precedence
• CPC Class Codes: H05K 1/189 characterised by the use of a flexible or folded printed circuit H05K3/326 takes precedence
• CPC Class Codes: H05K 2201/09036 Recesses or grooves in insulating substrate
• CPC Class Codes: H05K 2201/0979 Redundant conductors or connections, i.e. more than one current path between two points
• CPC Class Codes: H05K 2201/10128 Display
• CPC Class Codes: H10K 2102/311 Flexible OLED
• CPC Class Codes: H10K 59/121 characterised by the geometry or disposition of pixel elements
• CPC Class Codes: H10K 59/131 Interconnections, e.g. wiring lines or terminals
• CPC Class Codes: H10K 77/111 Flexible substrates
• CPC Class Codes: Y02E 10/549 Organic PV cells

Abstract

An electronic device may be provided with an organic light-emitting diode display with minimized border regions. The border regions may be minimized by providing the display with bent edge portions having neutral plane adjustment features that facilitate bending of the bent edge portions while minimizing damage to the bent edge portions. The neutral plane adjustment features may include a modified backfilm layer of the display in which portions of the backfilm layer are removed in a bend region. A display device may include a substrate, a display panel on the substrate having display pixels, and peripheral circuitry proximate the display panel and configured to drive the display pixels. A portion of the periphery of the substrate may be bent substantially orthogonal to the display panel to reduce an apparent surface area of the display device. The bent portion may include an electrode for communication with the peripheral circuitry.

Claims

1. A display, comprising:

a first polymer layer with an active area that contains an array of thin-film transistors and an inactive area that includes bent edge portions of the first polymer layer; and

a second polymer layer attached to the first polymer layer, wherein the second polymer layer includes at least one neutral plane adjustment feature that facilitates bending of the bend edge portions of the first polymer layer.

2. The display defined in claim 1 wherein the first polymer layer comprises polyimide.

3. The display defined in claim 2 wherein the second polymer layer comprises polyethylene terephthalate.

4. The display defined in claim 1 wherein the bent edge portions of the first polymer layer extend beyond an edge of the second polymer layer and bend around the edge of the second polymer layer.

5. The display defined in claim 1 wherein the second polymer layer includes a gap that extends along at least some of the bent edge portions of the first polymer layer.

6. The display defined in claim 1 wherein the second polymer layer has a first portion that is attached to the first polymer layer in the active area and a second portion that is attached to the bent edge portions of the first polymer layer, wherein the first portion has a first thickness, wherein the second portion has a second thickness, and wherein the second thickness is smaller than the first thickness.

7. The display defined in claim 1 wherein the second polymer layer comprises first and second sublayers, wherein the first sublayer is attached to the bent edge portions of the first polymer layer, and wherein at least some of the second sublayer is free to travel with respect to the first sublayer.

8. The display defined in claim 1, further comprising:

conductive traces on the first polymer layer that extend from the active area over the bent edge portions, wherein each conductive trace splits into multiple sub-traces on the bent edge portions of the first polymer layer.

9. The display defined in claim 8 wherein the multiple sub-traces of each conductive trace comprise at least four sub-traces.

10. A method of forming an organic light-emitting diode display, comprising:

forming display structures on a polymer substrate that is attached to a glass carrier substrate;

attaching an integrated circuit to the polymer substrate;

removing the glass carrier substrate;

attaching a backfilm layer to the polymer substrate; and

bending an edge region of the polymer substrate, wherein the edge region of the polymer substrate is adjacent to a portion of the backfilm layer that includes neutral plane adjustment features.

11. The method defined in claim 10, further comprising:

removing at least some of the backfilm layer that has been attached to the polymer substrate to form the neutral plane adjustment features.

12. The method defined in claim 11 wherein removing the at least some of the backfilm layer that has been attached to the polymer substrate comprises cutting the backfilm layer along the edge region of the polymer substrate.

13. The method defined in claim 10 wherein attaching the backfilm layer to the polymer substrate comprises attaching a pre-cut backfilm layer having the neutral plane adjustment features to the polymer substrate.

14. A display device with a reduced border region, comprising:

a substrate;

a display panel on the substrate having a plurality of display pixels;

peripheral circuitry on the substrate that is proximate to the display panel and that is configured to drive the plurality of display pixels; and

a flexible carrier attached to the substrate, wherein a portion of the substrate and a portion of the flexible carrier are bent substantially orthogonal to the display panel and wherein a bend region of the flexible carrier includes a series of trenches.

15. The display device defined in claim 14, further comprising:

at least one electrode coupled to the peripheral circuitry, wherein a bend region of the substrate includes a portion of the at least one electrode.

16. The display device defined in claim 15 wherein the peripheral circuitry comprises a first component and a second component and wherein the portion of the at least one electrode comprises a bent electrical interconnection between the first component and the second component.

17. The display device defined in claim 16 wherein the bent electrical interconnection is configured to conduct display communication signals between the first component and the second component.

18. The display device defined in claim 15 wherein the portion of the at least one electrode in the bend region of the substrate is arranged in a pattern selected from the group consisting of a waving pattern, a sinusoidal pattern, an alternating pattern, and a disruptive planar pattern.

19. The display device defined in claim 15 wherein the at least one electrode includes an additional portion that is located outside the bend region of the substrate, wherein the portion of the at least one electrode is formed from a flexible conductor, and wherein the additional portion of the at least one electrode is formed from a conductive material that is different from the flexible conductor.

20. The display device defined in claim 15 wherein the at least one electrode includes an additional portion that is located outside the bend region of the substrate, wherein the portion of the at least one electrode has a bend thickness, and wherein the additional portion of the at least one electrode has a thickness that is greater than the bend thickness.

21. The display device defined in claim 15 wherein the at least one electrode includes an additional portion that is located outside the bend region of the substrate, wherein the portion of the at least one electrode has a bend thickness, and wherein the additional portion of the at least one electrode has a thickness that is less than the bend thickness.

22. The display device defined in claim 15, further comprising:

conductive material that is suspended in an adhesive film that fills surface imperfections in an outer surface of the portion of the at least one electrode.

23. The display device defined in claim 14 wherein the series of trenches comprises a series of triangular trenches.

24. A method of forming a display, comprising:

identifying a bend region on a flexible carrier substrate;

forming a series of trenches in the flexible carrier substrate in the bend region;

attaching the flexible carrier substrate to display layers; and

bending the flexible carrier substrate and at least some of the attached display layers in the bend region.

25. The method defined in claim 24, further comprising:

before identifying the bend region on the flexible carrier substrate, attaching a substrate to a rigid carrier; and

forming a display panel and peripheral circuitry on the substrate to form the display layers.

26. The method defined in claim 25, further comprising:

separating the substrate from the rigid carrier.

27. The method defined in claim 26 wherein attaching the flexible carrier substrate to the display layers comprises attaching a first surface of the flexible carrier substrate to the substrate and wherein forming the series of trenches in the flexible carrier substrate in the bend region comprises forming the series of trenches in an opposing second surface of the flexible carrier substrate.

28. The method defined in claim 27 wherein bending the flexible carrier substrate and the at least some of the attached display layers in the bend region comprises:

bending the substrate and the flexible carrier substrate substantially orthogonal to the display panel at a bend line that intersects the series of trenches.