BACKGROUND OF THE INVENTION

1. Field of the Invention

One or more embodiments of the present invention relate to a display device.

2. Description of the Related Art

A flat panel display such as an organic electroluminescence (EL) display device includes a display panel in which thin film transistors (TFTs), organic light-emitting diodes (OLEDs), and the like are formed on a substrate. A glass substrate has been conventionally used for a base material of the display panel; however, development of a flexible display in which the display panel can be bent has recently progressed using a resin film such as a polyimide film or the like for the base material.

As applications of the flexible display, it is considered to achieve a narrower picture frame by folding a mount portion for an integrated circuit (IC) or a flexible printed circuit (FPC), which is provided outside an image display region of the display panel, onto the rear side of the display region.

U.S. Patent Application Publication No. 2016/0172428 discloses a configuration in which, in a curved region formed by folding the mount portion onto the rear surface side of the display region, a plurality of wiring lines at different potentials are provided on the upper surface of an insulating sheet.

SUMMARY OF THE INVENTION

However, in the conventional configuration, short prevention between the plurality of wiring lines at different potentials is not sufficient. That is, in the curved region, the rigidity of the insulating sheet needs to be reduced, and therefore, it is desirable to make the film thickness of the insulating sheet thin. However, when the film thickness of the insulating sheet is made thin in a stepwise manner, a step portion connecting the plurality of wiring lines may be generated. At this step portion, when a wiring layer is formed on the upper surface of the insulating sheet and then the wiring layer is processed into a wiring line shape by dry etching or the like, there is a possibility that an unnecessary wiring layer is not removed but remains. As a result, there is a risk that a short occurs because the remaining portion of the wiring layer electrically connects the plurality of wiring lines at different potentials.

One or more embodiments of the invention have been made in view of the problem, and it is an object thereof to achieve short prevention between a plurality of wiring lines at different potentials in a curved region.

(1) A display device according to the disclosure includes a display panel including a display region including a pixel array portion, a drive portion forming region provided on a rear surface side of the display region and including a drive portion driving the pixel array portion, and a curved region coupling the display region with the drive portion forming region, wherein the display panel includes an insulating sheet provided from the display region to the drive portion forming region, including, in the curved region, a first film-thickness region having a first film thickness thinner than a film thickness at the display region and a film thickness at the drive portion forming region, and including a first step portion disposed between the display region and the first film-thickness region and a second step portion disposed between the drive portion forming region and the first film-thickness region, first and second wiring lines crossing the first step portion and the second step portion above the insulating sheet and electrically connecting the pixel array portion with the drive portion, and an insulating wall extending from the first step portion to the second step portion between the first wiring line and the second wiring line.

(2) In the display device according to the above-mentioned (1), an upper surface of the insulating wall may be continuous with an upper surface of the insulating sheet in the display region and the drive portion forming region.

(3) The display device according to the above-mentioned (1) or (2) may include a first conductor disposed at the first step portion and the second step portion.

(4) In the display device according to any one of the above-mentioned (1) to (3), the insulating sheet may include, on a center side of the first film-thickness region, a second film-thickness region having a second film thickness thinner than the first film thickness, and at least one of the first wiring line and the second wiring line may be disposed so as to cross a third step portion disposed between the first film-thickness region and the second film-thickness region.

(5) The display device according to the above-mentioned (4) may include a second conductor disposed at the third step portion.

(6) In the display device according to the above-mentioned (4) or (5), the insulating sheet may include an insulating base material and a first insulating film provided on the insulating base material, and an upper surface of the insulating base material may be exposed from at least a portion of the first insulating film in the second film-thickness region.

(7) In the display device according to the above-mentioned (6), the insulating base material may be made of polyimide.

(8) In the display device according to the above-mentioned (6), the first insulating film may be formed of a stacked body of a silicon oxide layer and a silicon nitride layer.

(9) In the display device according to the above-mentioned (6), the insulating sheet may further include a second insulating film between the first insulating film in the display region and the first wiring line and between the first insulating film and the second wiring line.

(10) In the display device according to the above-mentioned (9), a step reducing layer may be provided between the second insulating film and the first insulating film.

(11) In the display device according to the above-mentioned (9) or (10), at least a portion of the insulating wall may be made of the same material as the second insulating film.

(12) In the display device according to any one of the above-mentioned (1) to (11), the first wiring line and the second wiring line may be signal lines at different potentials.

(13) A display device according to the disclosure includes a display panel including a display region including a pixel array portion, a drive portion forming region provided on a rear surface side of the display region and including a drive portion driving the pixel array portion, and a curved region coupling the display region with the drive portion forming region, wherein the display panel includes an insulating base material made of an organic material, an inorganic insulating film provided on the insulating base material, made of an inorganic insulating material, provided from the display region to the drive portion forming region, including, in the curved region, a first film-thickness region having a first film thickness thinner than a film thickness at the display region and a film thickness at the drive portion forming region, and including a first step portion disposed between the display region and the first film-thickness region and a second step portion disposed between the drive portion forming region and the first film-thickness region, first and second wiring lines crossing the first step portion and the second step portion above the inorganic insulating film and electrically connecting the pixel array portion with the drive portion, and an insulating wall extending from the first step portion to the second step portion between the first wiring line and the second wiring line.

(14) In the display device according to the above-mentioned (13), an upper surface of the insulating wall may be continuous with an upper surface of the inorganic insulating film in the display region and the drive portion forming region.

(15) The display device according to the above-mentioned (13) or (14) may include a first conductor disposed at the first step portion and the second step portion.

(16) In the display device according to any one of the above-mentioned (13) to (15), the inorganic insulating film may include, on a center side of the first film-thickness region, a second film-thickness region having a second film thickness thinner than the first film thickness, and at least one of the first wiring line and the second wiring line may be disposed so as to cross a third step portion disposed between the first film-thickness region and the second film-thickness region.

(17) In the display device according to the above-mentioned (13), the inorganic insulating film may include a first insulating film disposed between the insulating base material and the first and second wiring lines, and a second insulating film disposed between the first insulating film and the first and second wiring lines.

(18) In the display device according to the above-mentioned (17), a step reducing layer may be provided between the second insulating film and the first insulating film.

(19) In the display device according to the above-mentioned (17) or (18), at least a portion of the insulating wall may be made of the same material as the second insulating film.

