KR20180079559A - Edge Bending Display Device - Google Patents

Abstract

According to the present invention, a curved surface display device comprises a back plate, a driving circuit unit, and a power supply line. The back plate is divided into a display area, in which a plurality of pixels are arranged, and a non-display area surrounding an edge of the display area. The driving circuit unit drives the pixels. The power supply line is connected to the driving circuit unit and is arranged to surround the display area in the back plate. The power supply line is defined as a space between an inner side adjacent to the display area and an outer side opposite to the inner side, and comprises a crack inducing pattern formed in at least one area of the outer side, wherein the crack inducing pattern is curved toward the inner side. According to the present invention, it is possible to prevent a crack due to stress generated when a flexible display panel is attached to a curved cover glass, from transferring to the driving circuit unit.

Description

BACKGROUND OF THE INVENTION Field of the Invention [0001] The present invention relates to a curved surface display device having a side bending structure,

The present invention relates to a curved surface display device having a side / side bend structure.

2. Description of the Related Art Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of cathode ray tubes (CRTs), have been developed. Such flat panel display devices include a liquid crystal display (LCD), a field emission display (FED), a plasma display panel (PDP), and an electroluminescence device (EL) have.

Since the flat panel display is thin and light in weight, it is widely used as a display means in a mobile communication terminal or a portable information processor. Particularly, there is a growing demand for display panels that are thinner, lighter, and have lower power consumption in portable or mobile devices.

Such an electroluminescent display device receives the spotlight as a display device most suitable for the demand. The electroluminescent device is divided into an inorganic electroluminescent device and an organic light emitting diode device depending on the material of the light emitting layer, and has a self-luminous self-luminous device, which has a high response speed and high luminous efficiency, luminance and viewing angle. The organic light emitting diode display device has an organic light emitting diode (OLED).

The organic light emitting diode includes an organic electroluminescent compound layer that emits light by an electric field, and a cathode electrode and an anode that face each other with the organic electroluminescent compound layer interposed therebetween. The organic electroluminescent compound layer includes a hole injection layer (HIL), a hole transport layer (HTL), an emission layer (EML), an electron transport layer (ETL), and an electron injection layer layer, EIL). The OLED emits electrons due to the energy generated from the excitons and excitons formed in the excitation process when the holes and electrons injected into the cathode and the cathode are recombined in the emission layer (EML).

2. Description of the Related Art An organic light emitting diode display (OLEDD) using an organic light emitting diode (OLED) as an electroluminescent device includes a passive matrix type organic light emitting diode display (PMOLED) Type organic light emitting diode display device (Active Matrix type Organic Light Emitting Diode Display (AMOLED)). In addition, depending on the direction in which the light is emitted, there are a top-emission type and a bottom-emission type.

Particularly, the liquid crystal display device and the plasma display device have limitations in developing a self-luminous element having high flexibility and elasticity, and thus there is a limit in application to a flexible display device. However, the organic light emitting diode display device is formed by using an organic thin film. Therefore, attention is focused on an optimum material that can be applied to a flexible display device by taking advantage of the flexibility and elasticity characteristic of the organic thin film. An active matrix type flexible organic light emitting diode display device (flexible AMOLED) displays an image by controlling a current flowing in an organic light emitting diode using a thin film transistor (TFT).

2. Description of the Related Art In recent years, flexible organic light emitting diode display devices have been actively developed. In order to manufacture a flexible display device, a new problem arises due to physical stress in the process of bending the flat display panel in a curved shape.

The present invention provides a structure for reducing the influence of cracks caused by stress generated in the bending axis in the process of bending the sides of the flexible organic light emitting diode display panel and attaching it to the cover glass.

In order to achieve the object of the present invention, a curved surface display device according to the present invention includes a back plate, a driving circuit, and a power supply line. The back plate is divided into a display area in which a plurality of pixels are arranged and a non-display area surrounding the edge of the display area. The driving circuit portion drives the pixels. The power supply line is connected to the drive circuit, and is arranged to surround the display area on the back plate. The power supply line is defined as an inner side adjacent to the display area and an outer side opposite to the inner side, and at least a part of the outer side has a crack inducing pattern that is broken in the inner side direction.

The present invention can prevent a crack generated due to stress when the flexible display panel is attached to a curved cover glass, from propagating to a driving circuit portion such as a driving circuit portion.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view showing a structure of an organic light emitting diode display device having a lateral side / side bending structure according to the present invention; FIG.
BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light emitting diode (OLED) display device having a lateral bending structure.
3 is an enlarged sectional view showing a curved structure of a curved display panel according to the present invention shown in Fig.
4 is a plan view showing a structure of a flexible organic light emitting diode display panel according to a first embodiment of the present invention.
5 is a cross-sectional view showing a structure of a flexible organic light emitting diode display panel according to a first embodiment of the present invention, cut into a perforated line II-II 'in FIG.
6 is a view showing a plane of a power supply line according to the first embodiment;
7 is a view for explaining the angle of the central axis of the crack inducing pattern.
8 to 10 are cross-sectional views showing embodiments of power supply lines.
11 is a view showing a plane of a power supply line according to the second embodiment;

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Like reference numerals throughout the specification denote substantially identical components. In the following description, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. In addition, the component names used in the following description may be selected in consideration of easiness of specification, and may be different from the parts names of actual products.

Hereinafter, a curved display device according to the present invention will be described with reference to the drawings.

1 is a perspective view showing a curved surface display device having a side bending structure according to the present invention.

Referring to FIG. 1, an organic light emitting diode display device having a side bending structure includes a main panel MP and a curved display panel (CDP). The curved surface display panel (CDP) refers to a display panel in which a part of the display surface is curved or warped. For example, it refers to a display panel that does not affect the display element at all and performs a normal display function unless it is bent or bent to 90 degrees or more and 180 degrees or completely folded. Here, for the purpose of realizing a display device having a side bending structure, in the case of a display panel in which a curved surface portion is disposed on a side surface, it is also referred to as a curved display panel.

The main panel MP has a substantially rectangular thin plate-like structure. The main panel MP may include various devices for driving the curved display panel CDP. For example, in the case of a mobile communication terminal (mobile phone), various components having a communication function can be provided. In the case of a portable personal computer, various components for a computer function may be provided. A curved display panel (CDP) is attached to the front surface of the main panel (MP).

The curved surface display panel (CDP) has a side bending structure. For example, a flat display surface PS and a curved display surface CS. The flat display surface PS is a flat surface occupying most of the curved display panel CDP. The curved surface display surface CS is a curved surface extending from the left side and the right side of the flat display surface PS, respectively. In particular, the curved surface display surface CS may have a curved shape corresponding to 1/4 of the cylinder.

When a curved surface display panel (CDP) is applied to a portable telephone, the left side and the right side corresponding to the long side may have a structure bent 90 degrees toward the back side. Therefore, when viewed from the front, there are no non-display areas or bezel areas on the left side and the right side. On the other hand, it is possible to have a non-display area having a constant width at the upper side and the lower side corresponding to the shorter side. In the non-display area of the upper and lower sides, an external display device such as a product name or a manufacturer's logo, or an external input device such as a microphone, a speaker, a camera lens, or an optical sensor can be disposed.

Hereinafter, the curved display panel (CDP) will be described in detail with reference to Figs. 2 and 3. Fig. FIG. 2 is a cross-sectional view illustrating a structure of a curved display panel used in an organic light emitting diode display device having a side bending structure according to the present invention. 3 is an enlarged sectional view showing a curved structure of a curved display panel according to the present invention shown in Fig.

As shown in Fig. 2, the curved surface display panel CDP includes a flexible display panel FDP and a cover glass CG. The flexible display panel FDP is a display panel in which the entire display panel is excellent in elasticity and flexibility and is not held in a flat state but is free to bend or bend. In the present invention, for the sake of convenience, the flexible display panel (FDP) is referred to as a flexible display panel. On the other hand, a display panel bonded to a cover glass (CG) having a hard surface but having a curved surface is called a curved surface display panel (CDP). In the following description, the flexible display panel FDP will be described as a flexible organic light emitting diode display panel. However, the present invention is not necessarily limited to this, and the spirit of the present invention can be equally applied to other display panels that can secure flexibility.

The flexible display panel FDP includes a back plate BP, a flexible substrate PI, a touch screen film TSP, and a polarizing film POL.

It is preferable that the back plate BP is a film material which is flexible yet flexible while having rigidity for protecting the flexible substrate PI.

The flexible substrate PI is positioned on the back plate BP and a plurality of thin film transistors are formed on the flexible substrate PI. The flexible substrate PI may be a polyimide substrate.

A touch screen film (TSP) is attached to the flexible substrate (PI) using a pressure sensitive adhesive (PSA).

The touch screen film (TSP) is adhered to the flexible substrate (PI) via a pressure-sensitive adhesive (PSA) having a property of suppressing bubble generation. The on-cell type touch screen film (TSP) senses the user's touch input. The polarizing film (POL) is attached to the touch screen film (TSP) by a laminating method.

Since the flexible display panel (FDP) is easily bent, it can be applied to various display devices. In the present invention, a flexible display panel (FDP) is attached to the inner side of a "U" -shaped cover glass (CG) whose sides are slightly curved to provide a curved display panel (CDP) which can use the upper surface and the curved side as a display area do.

The flexible display panel FDP can be attached to the inner surface of the cover glass CG using an optical adhesive (OCA).

As described above, in order to achieve a structure in which a part of the side surface is bent, a method of surface-bonding the flexible display panel (FDP) to the inner surface of the cover glass (CG) curved side is used. In this case, as shown in Fig. 3, a bending stress may occur in a curved portion of the flexible display panel FDP, that is, a curved portion that is a portion facing the curved display surface CS. Bending stresses can cause various defects. For example, cracks or depressions may occur in the thin films constituting the flexible substrate PI.

The present invention provides a structure capable of preventing a crack generated in thin films by an assembling force. In particular, the present invention provides an organic light emitting diode (OLED) display device having a lateral bending structure with a crack prevention pattern for improving a problem caused by cracking due to bending stress at a stepped portion generated in a curved portion.

Hereinafter, the structure and function of the crack prevention pattern will be described.

4 is a plan view showing a structure of a flexible display panel according to the present invention. 5 is a cross-sectional view showing a structure cut along a perforated line II-II 'in FIG.

4 and 5, the flexible display panel FDP includes a rectangular flexible back plate BP. The back plate BP is divided into a display area AA and a non-display area NA. The display area AA is an area for directly displaying video information represented by the display device, and is disposed at the center of the back plate BP. The non-display area NA is an area disposed around the display area AA and in which driving elements necessary for driving the display elements arranged in the display area AA are disposed. In the display area AA, an organic light emitting diode and thin film transistors for driving the organic light emitting diode are formed. The non-display area NA is provided with a gate driver GIP and a driving circuit DIC, which are necessary for performing a display function.

The gate driver GIP supplies gate pulses to the pixels through the gate line GL. The gate driver GIP may be formed simultaneously with the thin film transistors formed in the display area AA. Fig. 4 shows a structure in which both gate drivers (GIP) are disposed on both sides, but may be disposed on either side of the display area AA.

The driving circuit unit DIC also functions as a timing controller and a data driving unit. The data driver DIC supplies the data voltages to the pixels P through the data line DL. In addition, the driving circuit portion DIC supplies a constant voltage to the pixels P through the power supply line VL. The data lines DL are arranged in the column direction in the display area AA. The power supply line VL supplies a constant voltage of the same magnitude to all of the pixels P so that the power supply line VL surrounds the edge of the display area AA in order to minimize the RC delay, (Not shown) arranged in the direction of the arrow. The power supply line VL may be a high potential driving voltage VDD or a low potential driving voltage VSS for driving the pixel P. [ The driving circuit portion DIC may be mounted on the back plate BP or mounted on the flexible circuit board and connected to the back plate BP.

The touch screen film TSP is stuck to cover the display area AA. The touch driving circuit TIC is disposed on one side of the touch screen film TSP in the non-display area AA.

The polarizing film POL is arranged to cover the display area AA on the touch screen film TSP. The polarizing film POL is attached so as to expose a region where the touch driving circuits TIC are attached.

5 is a cross-sectional view taken along the line II-II 'shown in FIG.

Referring to FIG. 5, a touch driving circuit (TIC) is attached to one side of a touch screen film (TSP) bonded to a flexible substrate (PI). The touch driver circuit TIC may be implemented in the form of an integrated circuit mounted on a flexible circuit board. The polarizing film POL should be attached so as not to cover the touch driving circuit TIC. Since the optical adhesive OCA is located on the polarizing film POL, the step between the flexible substrate PI and the cover glass CG becomes severe at the crack weakened portion CWA not covered by the polarizing film POL. Cracks tend to occur in a region where the step between the flexible substrate PI and the cover glass CG is severe in the process of attaching the flexible display panel FDP and the cover glass CG. That is, the crack weakened portion (CWA) can be defined as a planar region overlapping the touch screen film (TSP) exposed from the polarizing film (POL).

The power supply line (VL) located in the crack vulnerability (CWA) is vulnerable to cracks. When a crack occurs in the power supply line VL, a crack may propagate along the flexible substrate PI, thereby damaging the display area AA or the driving circuit part DIC and the data line DL. If physical damage is applied to the display area AA or the driving circuit part DIC due to a crack, the display device can be seriously damaged.

In the power supply line (VL) according to the present invention, when a crack is generated, a crack inducing pattern is formed so that cracks do not propagate to the display area (AA) or the driving circuit part (DIC).

FIG. 6 is a plan view of a power supply line according to the first embodiment, and FIG. 7 is a cross-sectional view taken along the line III-III 'shown in FIG. Hereinafter, the shape of the crack inducing pattern defined in this specification will be described with reference to the region shown in the plan view shown in FIG.

6 and 7, the power supply line VL has an inner side LI and an outer side LO, and a crack inducing pattern CGP is formed on the outer side LO. The inner side LI refers to the side adjacent to the display area AA and the outer side LO refers to the side opposite to the inner side LI.

The crack inducing pattern (CGP) is in the form of a groove which is broken in the direction of the inner side (LI) from the outer side (LO). The crack inducing pattern CGP has a rectangular shape defined by first and second side faces S1 and S2 connecting the opening OL, the end edge EL facing the opening OL, the opening OL and the end edge EL. Lt; / RTI > The center axis CL of the crack inducing pattern CGP is defined as a straight line connecting the center C1 of the opening OL and the center C2 of the end edge EL.

7 is a view for explaining conditions for setting the size of the angle formed by the center axis and the outer side of the crack inducing pattern.

The crack weakened portion CWA is located in the non-display region AA, the display region AA is located below the side surface, and the driving circuit portion DIC is located above the side surface. Since the display area AA is in close proximity to the crack weakened portion CWA, it is preferable that the crack is induced in the upper direction in which the drive circuit portion DIC is located. Therefore, the center axis CL of the crack inducing pattern CGP is formed to be inclined toward the upper direction.

The center axis CL of the crack inducing pattern CGP should not be in contact with the display area AA and the driving circuit part DIC. Since the center axis CL is inclined upward, the center axis CL has an angle of incidence O which is an acute angle formed by the center axis CL and the outer side LO. (DIC).

Therefore, the angle O of the crack inducing pattern CGP is set to an angle smaller than the reference angle of incidence O.

The tangential line CL1 represents the angle between the center OL1 of the opening OL and the upper side of the driving circuit portion DIC Quot; refers to a straight line connecting the point where the end (EP) meets.

The crack inducing pattern CGP formed under such conditions induces a direction in which a crack propagates when a crack occurs in the power supply line VL. That is, when a crack occurs in the power supply line VL, the crack propagates in the direction of the center axis CL of the crack inducing pattern CGP. Since the center axis CL of the crack inducing pattern CGP is designed not to come in contact with the driving circuit portion DIC, the driving circuit portion DIC is less likely to be damaged by cracks.

8 to 10 are cross-sectional views of a power supply line according to the present invention. The power supply line VL may be formed of a single metal layer, but may be formed of a double metal layer as shown in FIGS. That is, the power supply line VL has a structure in which the first metal layer MET1 and the second metal layer MET2 are stacked. Then, the crack inducing pattern CGP may be patterned into the second metal layer MET2 as shown in FIG. Alternatively, as shown in FIG. 9, the crack inducing pattern CGP may be patterned in the first metal layer MET1. Alternatively, as shown in FIG. 10, the crack inducing pattern CGP may be patterned in both the first and second metal layers MET1 and MET2.

11 is a plan view of the power supply line according to the second embodiment.

Referring to FIG. 11, the crack inducing pattern CGP of the power supply line according to the second embodiment may be in the form of a triangle formed by the opening OL, the first and second sides S1 and S2. The center axis CL in the second embodiment can be defined as a straight line connecting the center of the opening OL and the vertex C2 at which the first and second side edges S1 and S2 abut. In the second embodiment, the angle O between the center axis CL and the outer side LO can be set under the same conditions as in the first embodiment.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Therefore, the present invention should not be limited to the details described in the detailed description, but should be defined by the claims.

ST: switching thin film transistor DT: driving thin film transistor
GL: scan wiring DL: data wiring
ANO: anode electrode CAT: cathode electrode
POL: polarizing film
CGP: Crack induction pattern

Claims (6)

A back plate divided into a display area where a plurality of pixels are arranged and a non-display area surrounding an edge of the display area;
A driving circuit for driving the pixels; And
And a power supply line connected to the driving circuit portion and arranged to surround the display region on the back plate,
Wherein the power supply line is defined as an inner side adjacent to the display area and an outer side opposite to the inner side,
And at least a part of the outer side has a crack inducing pattern which is broken in the inner side direction.
The method according to claim 1,
A touch screen film covering the display area at an upper portion of the back plate; And
Further comprising a polarizing film on an upper portion of the touch screen film, the polarizing film having a smaller area than the touch screen and covering the display region,
The crack-
Wherein the non-display region is formed in a region located on a side surface of the touch screen film that is not covered by the polarizing film.
The method according to claim 1,
Wherein the crack inducing pattern has a rectangular shape defined by an opening portion, an end portion facing the opening portion, side portions connecting the opening portion and the end surface,
Wherein an extension line of a center axis connecting the center of the opening of the outer side and the center of the end side is not in contact with the drive circuit portion.
The method of claim 3,
Wherein the crack inducing pattern is defined as an opening portion, first and second side portions extending in the inner side direction at the opening portion and meeting at apexes,
Wherein an extension line of a central axis connecting the center of the opening of the outer side and the vertex does not come in contact with the driving circuit portion.
The method according to claim 1,
Wherein the power supply line is a base low-voltage line that supplies a low-potential driving voltage to the pixels.
6. The method of claim 5,
Wherein the power supply line has a structure in which a first metal layer and a second metal layer are stacked,
Wherein the crack inducing pattern is formed on at least one metal layer of the first metal layer or the second metal layer.

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