KR102600186B1 - Edge Bending Display Device - Google Patents

Abstract

The curved 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 where multiple pixels are placed and a non-display area surrounding the edges of the display area. The driving circuit drives the pixels. The power supply line is connected to the driving circuit and is arranged to surround the display area on the back plate. The power supply line is defined between the inner side adjacent to the display area and the outer side opposite to the inner side, and at least a portion of the outer side has a crack induction pattern dug in the direction of the inner side.

Description

Curved display device with side bending structure {Edge Bending Display Device}

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

Recently, various flat panel display devices that can reduce the weight and volume, which are disadvantages of cathode ray tubes, are being developed. These flat panel displays include Liquid Crystal Display (LCD), Field Emission Display (FED), Plasma Display Panel (PDP), and Electroluminescence Device (EL). there is.

Flat panel displays are thin and light, so they are widely used as display devices in mobile communication terminals and portable information processors. In particular, in portable or mobile devices, the demand for display panels that are thinner, lighter, and consume less power is increasing.

Electroluminescent display devices are receiving attention as the display elements most suitable for these needs. Electroluminescent devices are roughly divided into inorganic electroluminescent devices and organic light-emitting diode devices depending on the material of the light-emitting layer. They use self-luminous devices that emit light on their own, so they have the advantages of fast response speed, high luminous efficiency, brightness, and viewing angle. Organic light emitting diode displays have organic light emitting diodes (OLED).

The organic light emitting diode includes an organic electroluminescent compound layer that emits light by an electric field, and a cathode and anode electrodes facing 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). In OLED, excitons are formed during the excitation process when holes and electrons injected into the cathode and cathode recombine in the light emitting layer (EML), and emit light due to the energy from the excitons.

Organic Light Emitting Diode display (OLEDD), which utilizes the characteristics of organic light emitting diode, an electroluminescent device, includes passive matrix type Organic Light Emitting Diode display (PMOLED) and active matrix. It is broadly classified into two types of organic light emitting diode displays (Active Matrix type Organic Light Emitting Diode display, AMOLED). Additionally, depending on the direction in which light is emitted, there are a top-emission method and a bottom-emission method.

In particular, liquid crystal displays and plasma displays have limitations in developing self-luminous devices with high flexibility and elasticity, which limits their application as flexible displays. However, organic light-emitting diode displays are formed using organic thin films, and interest is focused as an optimal material that can be applied to flexible displays by utilizing the flexibility and elasticity that are characteristics of organic thin films. An active matrix type flexible organic light emitting diode display (Flexible AMOLED) displays images by controlling the current flowing through the organic light emitting diode using a thin film transistor (TFT).

Recently, development of flexible organic light emitting diode display devices has been actively conducted. In order to manufacture flexible display devices, new problems are occurring due to physical stress on the structure in the process of bending a flat display panel into a curved shape.

The present invention is intended to provide a structure for reducing the effects of cracks caused by stress generated at the bending axis during the process of bending the side of a flexible organic light emitting diode display panel and bonding it to the cover glass.

In order to achieve the object of the present invention, the curved 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 where multiple pixels are placed and a non-display area surrounding the edges of the display area. The driving circuit drives the pixels. The power supply line is connected to the driving circuit and is arranged to surround the display area on the back plate. The power supply line is defined between the inner side adjacent to the display area and the outer side opposite to the inner side, and at least a portion of the outer side has a crack induction pattern dug in the direction of the inner side.

The present invention can prevent cracks generated due to stress when bonding a flexible display panel to a curved cover glass from propagating to driving circuit parts, such as the driving circuit part.

1 is a perspective view showing the structure of an organic light emitting diode display device having a side/side bending structure according to the present invention.
Figure 2 is a cross-sectional view showing a bonding 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.
Figure 3 is an enlarged cross-sectional view showing the structure of the curved portion of the curved display panel according to the present invention shown in Figure 2.
Figure 4 is a plan view showing the structure of a flexible organic light emitting diode display panel according to the first embodiment of the present invention.
Figure 5 is a cross-sectional view showing the structure of the flexible organic light emitting diode display panel according to the first embodiment of the present invention taken along the perforated line II-II' in Figure 4.
Figure 6 is a plan view showing the power supply line according to the first embodiment.
Figure 7 is a diagram for explaining the angle of the central axis of the crack induction pattern.
8 to 10 are cross-sectional views showing an example of a power supply line.
Figure 11 is a diagram showing a plane of a power supply line according to a second embodiment.

Hereinafter, preferred embodiments according to the present invention will be described in detail with reference to the attached drawings. Like reference numerals refer to substantially the same elements throughout the specification. In the following description, if it is determined that a detailed description of a known function or configuration related to the present invention may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. Additionally, the component names used in the following description may have been selected in consideration of ease of specification preparation, and may be different from the component names of the actual product.

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 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). A curved display panel (CDP) refers to a display panel in which a portion of the display surface is curved or curved. For example, even if it is bent or bent from 90 degrees to 180 degrees, as long as it is not completely folded, it does not affect the display elements at all and performs a normal display function. Here, it is intended to implement a display device having a structure where the sides are bent, and is also called a curved display panel in the case of a display panel in which curved portions are disposed on the sides.

The main panel MP has a substantially rectangular thin plate-shaped structure. The main panel (MP) can be equipped with various devices to drive the curved display panel (CDP). For example, a mobile communication terminal (cell phone) may be equipped with several components having communication functions. In the case of a portable personal computer, it may be equipped with several components for computer functions. A curved display panel (CDP) is attached to the front of the main panel (MP).

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

When a curved display panel (CDP) is applied to a portable phone, the left and right sides corresponding to the long sides may have a structure bent at 90 degrees toward the back. Therefore, when viewed from the front, there is no non-display area or bezel area on the left and right sides. On the other hand, the upper and lower sides corresponding to the short sides may have non-display areas with a certain width. In the non-display areas of the upper and lower sides, decorative marks such as the product name or manufacturer's logo, or external input devices such as a microphone, speaker, camera lens, or optical sensor can be placed.

Hereinafter, the curved display panel (CDP) will be described in detail with reference to FIGS. 2 and 3. Figure 2 is a cross-sectional view showing a bonding 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. Figure 3 is an enlarged cross-sectional view showing the structure of the curved portion of the curved display panel according to the present invention shown in Figure 2.

As shown in FIG. 2, the curved display panel (CDP) includes a flexible display panel (FDP) and a cover glass (CG). A flexible display panel (FDP) is a display panel that has excellent elasticity and flexibility as a whole, so it can be bent or bent freely rather than being kept flat. In the present invention, for convenience, a display panel whose entire display panel is flexible is called a flexible display panel (FDP). Meanwhile, a display panel bonded to a cover glass (CG) that is sturdy but has a curved surface was named a curved display panel (CDP). Additionally, in the following description, the flexible display panel (FDP) will be described in the case of a flexible organic light emitting diode display panel. However, it 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).

The back plate (BP) is preferably made of a film material that has the rigidity to protect the flexible substrate (PI) and is easily bendable yet elastic.

The flexible substrate (PI) is located on the back plate (BP), and a plurality of thin film transistors are formed on the flexible substrate (PI). The flexible substrate (PI) can use a polyimide substrate.

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

The touch screen film (TSP) is bonded to the flexible substrate (PI) using pressure-sensitive adhesive (PSA), which has the property of suppressing the generation of bubbles. 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) using a laminating method.

Flexible display panels (FDP) bend easily, so they can be applied to various types of display devices. In the present invention, a flexible display panel (FDP) is attached to the inner side of a "U"-shaped cover glass (CG) with a slightly curved side edge, thereby providing a curved display panel (CDP) that can be used as a display area even on the upper surface and the curved side. do.

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

In this way, in achieving a structure in which a portion of the side area is curved, a method of surface bonding the flexible display panel (FDP) to the inner surface of the cover glass (CG) where the side area is curved is used. In this case, as shown in FIG. 3, bending stress may occur in a bent portion of the flexible display panel (FDP), that is, a curved portion that faces the curved display surface (CS). Bending stress can cause a variety of defects. For example, cracks or compression may occur in the thin films that make up the flexible substrate (PI).

The present invention provides a structure that can prevent cracks occurring in thin films due to adhesion force. In particular, the present invention provides an organic light emitting diode display device having a side bending structure with a crack prevention pattern to improve problems when cracks occur due to bending stress in a step portion occurring in a curved portion.

Hereinafter, we will look at the structure and function of the crack prevention pattern.

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

Referring to FIGS. 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 that directly displays video information expressed by the display device and is located in the center of the back plate BP. The non-display area (NA) is arranged around the display area (AA) and is an area where driving elements necessary to drive the display elements arranged in the display area (AA) are arranged. Organic light emitting diodes and thin film transistors for driving them are formed in the display area (AA). In the non-display area (NA), a gate driver (GIP) and a driver circuit (DIC) necessary to perform the display function are disposed.

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

The driving circuit (DIC) functions as both a timing controller and a data driver. The data driver (DIC) supplies data voltage to the pixels (P) through the data line (DL). Additionally, the driving circuit unit (DIC) supplies a constant voltage to the pixels (P) through the power supply line (VL). The data lines DL are arranged in a column direction in the display area AA. Since the power supply line (VL) supplies a constant voltage of the same size to all pixels (P), in order to minimize RC delay, it surrounds the edge of the display area (AA) and moves in the row or column direction in the display area (AA). It is connected to a power line (not shown) arranged in this direction. 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 unit (DIC) may be mounted on the back plate (BP) or may be mounted on a flexible printed circuit board and connected to the back plate (BP).

The touch screen film (TSP) is bonded 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 bonded to expose the area where the touch driving circuit (TIC) is bonded.

FIG. 5 is a diagram showing a cross section taken along line II-II' shown in FIG. 4.

Referring to FIG. 5, a touch driving circuit (TIC) is bonded to one side of the touch screen film (TSP) bonded to the flexible substrate (PI). The touch driving circuit (TIC) can be implemented in the form of an integrated circuit mounted on a flexible circuit board. The polarizing film (POL) must be bonded so as not to cover the touch driving circuit (TIC). And because the optical adhesive (OCA) is located on the polarizing film (POL), the level difference between the flexible substrate (PI) and the cover glass (CG) increases in the crack vulnerable area (CWA) that is not covered by the polarizing film (POL). During the process of bonding the flexible display panel (FDP) and the cover glass (CG), cracks are likely to occur in areas where there is a large level difference between the flexible substrate (PI) and the cover glass (CG). That is, the crack vulnerable area (CWA) may be defined as a plane area that overlaps the touch screen film (TSP) exposed from the polarizing film (POL).

The power supply line (VL) located in the crack vulnerable area (CWA) is inevitably vulnerable to cracks. If a crack occurs in the power supply line (VL), the crack may propagate along the flexible substrate (PI) and cause damage to the display area (AA), driving circuit (DIC), and data line (DL). Physical damage caused by cracks to the display area (AA) or driving circuit (DIC) can cause fatal damage to the display device.

When a crack occurs in the power supply line (VL) according to the present invention, a crack induction pattern is formed to prevent the crack from propagating to the display area (AA) or the driving circuit (DIC).

FIG. 6 is a plan view showing the power supply line according to the first embodiment, and FIG. 7 is a view showing a cross section taken along line III-III' shown in FIG. 6. Hereinafter, the form of the crack induction pattern defined in this specification will be described focusing on the area shown in the plan view shown in FIG. 4.

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

The crack induction pattern (CGP) is in the form of grooves dug from the outer edge (LO) to the inner edge (LI). The crack induction pattern (CGP) is a rectangle defined by an opening (OL), an end edge (EL) facing the opening (OL), and first and second side edges (S1, S2) connecting the opening (OL) and the end edges (EL). It may be in the form of . And the central axis CL of the crack induction 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.

Figure 7 is a diagram illustrating conditions for setting the size of the angle between the central axis and the outer side of the crack induction pattern.

The crack vulnerable area (CWA) is located in the non-display area (AA), the display area (AA) is located at the bottom of the side, and the driving circuit (DIC) is located at the top of the side. Since the display area AA is located close to the crack vulnerable area CWA, it is preferable that the crack is guided toward the top where the driving circuit unit DIC is located. Accordingly, the central axis CL of the crack induction pattern CGP is formed to be inclined upward.

The central axis (CL) of the crack induction pattern (CGP) should not contact the display area (AA) and the driving circuit (DIC). Since the central axis (CL) is tilted upward, it has an included angle (O), which is an acute angle formed by the central axis (CL) and the outer side (LO). The smaller the included angle (O), the more the central axis (CL) moves toward the driving circuit. Stay away from (DIC).

Therefore, the included angle (O) of the crack induction pattern (CGP) is set to an angle smaller than the reference included angle (O).

The standard included angle (O) refers to the included angle (O), which is the acute angle formed by the tangent line (CL1) and the inner side (LI), and the tangent line (CL1) is between the center (OL1) of the opening (OL) and the upper side of the driving circuit (DIC). It refers to a straight line connecting the points where the ends (EP) meet.

The crack guidance pattern (CGP) formed under these conditions guides the direction in which the 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 central axis (CL) of the crack induction pattern (CGP). Since the central axis (CL) of the crack inducing pattern (CGP) is designed not to contact the driving circuit (DIC), the driving circuit (DIC) is less likely to be damaged by cracks.

8 to 10 are cross-sectional views of the power supply line according to the present invention. The power supply line VL may be formed of a single metal layer, but may also be formed of a double metal layer as shown in FIGS. 8 to 10. 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. Additionally, the crack induction pattern (CGP) may be patterned on the second metal layer (MET2) as shown in FIG. 8 . Alternatively, as shown in FIG. 9, the crack induction pattern (CGP) may be patterned on the first metal layer (MET1). Alternatively, as shown in FIG. 10, the crack induction pattern (CGP) may be patterned on both the first and second metal layers (MET1 and MET2).

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

Referring to FIG. 11, the crack induction pattern (CGP) of the power supply line according to the second embodiment may be in the form of a triangle consisting of an opening (OL) and first and second side sides (S1 and S2). In the second embodiment, the central axis CL may be defined as a straight line connecting the center of the opening OL and the vertex C2 where the first and second side sides S1 and S2 meet. In the second embodiment, the included angle O between the central axis CL and the outer side LO may be set to the same conditions as those in the first embodiment.

Through the above-described content, those skilled in the art will be able to see that various changes and modifications can be made without departing from the technical spirit of the present invention. Accordingly, the present invention should not be limited to what is described in the detailed description, but should be defined by the scope of the patent 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 on which a plurality of pixels are arranged and a non-display area surrounding an edge of the display area;
a driving circuit unit that drives the pixels; and
A power supply line connected to the driving circuit and 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,
At least a portion of the outer side has a crack induction pattern dug in the inner side,
The crack induction pattern is a curved display device in the form of a groove dug in the direction from the outer side to the inner side.
According to claim 1,
a touch screen film covering the display area at the top of the back plate; and
On top of the touch screen film, it further includes a polarizing film that has a smaller area than the touch screen and covers the display area,
The crack induction pattern is
A curved display device formed in an area located on a side of the touch screen film that is not obscured by the polarizing film among the non-display areas.
According to claim 1,
The crack inducing pattern has a rectangular shape defined by an opening, an end face facing the opening, and side edges connecting the opening and the end side,
A curved display device in which an extension line of a central axis connecting the center of the opening of the outer side and the center of the end side does not contact the driving circuit portion.
According to claim 3,
The crack inducing pattern is defined as an opening, first and second side edges extending from the opening toward the inner side and meeting at the vertex,
A curved display device in which an extension line of a central axis connecting the center of the opening of the outer side and the vertex does not contact the driving circuit portion.
According to claim 1,
The power supply line is a curved display device that is a low-potential driving voltage line that supplies a low-potential driving voltage to the pixels.
According to claim 5,
The power supply line has a structure in which a first metal layer and a second metal layer are stacked,
The crack inducing pattern is formed on at least one of the first metal layer and the second metal layer.

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