KR102433198B1 - Organic light emitting display device - Google Patents

Abstract

The present specification discloses an organic light emitting display device. The organic light emitting display device may include: a base layer having a display area displaying an image and a non-display area surrounding the display area; and a reflective layer provided to compensate for a color difference appearing at a boundary between the display area and the non-display area.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

This specification relates to an organic light emitting display device.

A video display device that implements various information on a screen is a key technology in the information and communication era, and is developing in the direction of thinner, lighter, more portable and high-performance. Accordingly, an organic light emitting display device that displays an image by controlling the amount of light emitted from the organic light emitting diode is in the spotlight.

The organic light emitting device is a self-luminous device using a thin light emitting layer between electrodes, and has the advantage that it can be thinned. A typical organic light emitting display device has a structure in which a pixel driving circuit and an organic light emitting device are formed on a substrate, and an image is displayed while light emitted from the organic light emitting device passes through a substrate or a barrier layer.

In recent years, attempts have been made to satisfy a user's aesthetic sense not only in the performance of the organic light emitting display device but also in its appearance. Among them, research to make various shapes of display devices and electronic devices (eg, smart phones, wearable devices) employing the display devices is also included. Furthermore, research to prevent/remove problems that may appear in a new-shaped display device is also being conducted.

The inventors of the present invention propose a special structure applied to the outer part of the display area by recognizing in detail the problems that appear in the display device having an unusual shape of the display area and conducting R&D.

The tasks of the present specification are not limited to the tasks mentioned above, and other tasks not mentioned will be clearly understood by those skilled in the art from the following description.

According to an embodiment of the present specification, an organic light emitting display device is provided. The organic light emitting display device may include: a base layer having a display area displaying an image and a non-display area surrounding the display area; and a reflective layer provided to compensate for a color difference appearing at a boundary between the display area and the non-display area.

The reflective layer may be the same material on the same layer as the uppermost reflective material of the display area. For example, the reflective layer may be made of the same material as the anode of the organic light emitting diode in the display area.

The reflective layer may be positioned between the anode of the display area and the connection metal layer of the non-display area. In this case, the connection metal layer is a part of a low-level power supply (VSS) wiring, and may connect the other part of the low-level power wiring and the cathode of the organic light emitting diode.

A display device according to another embodiment of the present specification includes: a first anode metal forming one electrode of an organic light emitting diode; a second anode metal forming a portion of a conducting wire that transmits low-level power to the organic light emitting diode; and a third anode metal positioned between the first anode metal and the second anode metal.

The third anode metal is provided to compensate for a color difference appearing outside the display area, and the third anode metal is isolated without being connected to the first anode metal and the second anode metal. That is, the third anode metal may be in an electrically floating state.

The details of other embodiments are included in the detailed description and drawings.

Embodiments of the present specification may provide a display device in which a problem is improved.

Accordingly, embodiments of the present specification may provide an organic light emitting display device.

Effects according to the embodiments of the present specification are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 illustrates an exemplary display device that may be included in an electronic device.
2 is a cross-sectional view schematically illustrating a display area and a non-display area of a display device.
3A and 3B are cross-sectional views illustrating color differences in some regions of a display device.
4A and 4B are diagrams illustrating a display device according to an exemplary embodiment of the present specification.

Advantages and features of the present specification and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the technical field to which the present invention belongs It is provided to fully inform the possessor of the scope of the invention, and the present invention is only defined by the scope of the claims.

The shapes, sizes, proportions, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present specification are exemplary, and thus the present specification is not limited to the illustrated matters. Like reference numerals refer to like elements throughout. In addition, in describing the present invention, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. When 'including', 'having', 'consisting', etc. mentioned in this specification are used, other parts may be added unless 'only' is used. When a component is expressed in the singular, the case in which the plural is included is included unless specifically stated otherwise. In interpreting the components, it is interpreted as including an error range even if there is no separate explicit description.

In the case of a description of the positional relationship, for example, when the positional relationship of two parts is described as 'on', 'on', 'on', 'beside', etc., 'right' Alternatively, one or more other parts may be positioned between two parts unless 'directly' is used. Reference to a device or layer “on” another device or layer includes any intervening layer or other device directly on or in the middle of another device. When it is described that a component is “connected”, “coupled” or “connected” to another component, the component may be directly connected or connected to the other component, but other components may be interposed between each component. It should be understood that each component may be “interposed” or “connected”, “coupled” or “connected” through another component.

Although first, second, etc. are used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component mentioned below may be the second component within the spirit of the present invention.

The size and thickness of each component shown in the drawings are illustrated for convenience of description, and the present invention is not necessarily limited to the size and thickness of the illustrated component. Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 illustrates an exemplary display device that may be included in an electronic device.

Referring to FIG. 1 , the display device 100 includes at least one active area, and an array of pixels is formed in the display area. One or more inactive areas may be disposed around the display area. That is, the non-display area may be adjacent to one or more side surfaces of the display area. In FIG. 1 , the non-display area surrounds the rectangular display area. However, the shape of the display area and the shape/arrangement of the non-display area adjacent to the display area are not limited to the example illustrated in FIG. 1 . The display area and the non-display area may have a shape suitable for designing an electronic device on which the display device 100 is mounted. Exemplary shapes of the display area are pentagonal, hexagonal, circular, oval, and the like.

Each pixel in the display area may be associated with a pixel circuit. The pixel circuit may include one or more switching transistors and one or more driving transistors on a backplane. Each pixel circuit may be electrically connected to a gate line and a data line to communicate with one or more driving circuits such as a gate driver and a data driver located in the non-display area.

As shown in FIG. 1 , the driving circuit may be implemented as a thin film transistor (TFT) in the non-display area. Such a driving circuit may be referred to as a gate-in-panel (GIP). In addition, some components such as data driver IC are mounted on a separate printed circuit board, and circuit films such as FPCB (flexible printed circuit board), COF (chip-on-film), TCP (tape-carrier-package), etc. It may be combined with the connection interface PAD disposed in the non-display area by using the PAD. The non-display area may be bent together with the connection interface, so that the printed circuit (COF, PCB, etc.) may be located behind the display device 100 .

The display device 100 may further include various additional elements for generating various signals or driving pixels in the display area. An additional element for driving the pixel may be an inverter circuit, a multiplexer, an electrostatic discharge circuit, or the like. The display device 100 may also include additional elements related to functions other than pixel driving. For example, the display device 100 may include additional elements that provide a touch sensing function, a user authentication function (eg, fingerprint recognition), a multi-level pressure sensing function, a tactile feedback function, and the like. The above-mentioned additional elements may be located in the non-display area and/or in an external circuit connected to the connection interface.

2 is a cross-sectional view schematically illustrating a display area and a non-display area of a display device.

The illustrated display area A/A and the non-display area I/A represent a cross-section taken along line I-I' in FIG. The display device will be described.

In the case of an organic light emitting display device, in the display area A/A, thin film transistors 102 , 104 , 108 , organic light emitting devices 112 , 114 , 116 and various functional layers are formed on the base layer 101 . are located Meanwhile, in the non-display area I/A, various circuits (eg, GIP), electrodes, wirings, functional structures, etc. may be positioned on the base layer 101 .

The base layer 101 supports various components of the organic light emitting diode display 100 . The base layer 101 may be formed of a transparent insulating material, for example, an insulating material such as glass or plastic. The substrate (array substrate) is also referred to as a concept including a device and a functional layer formed on the base layer 101, for example, a switching TFT, a driving TFT, an organic light emitting device, a protective film, and the like.

A buffer layer 130 may be positioned on the base layer 101 . The buffer layer is a functional layer for protecting a thin film transistor (TFT) from impurities such as alkali ions leaking from the base layer 101 or the underlying layers. The buffer layer may be formed of silicon oxide (SiOx), silicon nitride (SiNx), or a multilayer thereof. The buffer layer 130 may include a multi buffer and/or an active buffer.

A thin film transistor is placed on the base layer 101 or the buffer layer 130 . The thin film transistor may have a form in which a semiconductor layer, a gate insulator, a gate electrode, an interlayer dielectric layer (ILD), a source and a drain electrode are sequentially stacked. have. Alternatively, the thin film transistor may have a form in which a gate electrode 104 , a gate insulating layer 105 , a semiconductor layer 102 , and a source and drain electrode 108 are sequentially disposed as shown in FIG. 2 .

The semiconductor layer 102 may be made of polysilicon (p-Si), and in this case, a predetermined region may be doped with an impurity. In addition, the semiconductor layer 102 may be made of amorphous silicon (a-Si) or various organic semiconductor materials such as pentacene. Furthermore, the semiconductor layer 102 may be made of oxide.

The gate electrode 104 may be formed of various conductive materials, for example, magnesium (Mg), aluminum (Al), nickel (Ni), chromium (Cr), molybdenum (Mo), tungsten (W), gold (Au), or an alloy thereof. and the like.

The gate insulating layer 105 and the interlayer insulating layer ILD may be formed of an insulating material such as silicon oxide (SiOx) or silicon nitride (SiNx), and may also be formed of an insulating organic material. A contact hole through which the source and drain regions are exposed may be formed by selectively removing the gate insulating layer 105 and the interlayer insulating layer.

The source and drain electrodes 108 are formed on the gate insulating layer 105 or the interlayer insulating layer (ILD) in the form of a single layer or a multi-layered electrode material. If necessary, a passivation layer made of an inorganic insulating material may cover the source and drain electrodes 108 .

A planarization layer 107 may be disposed on the thin film transistor. The planarization layer 107 protects the thin film transistor and planarizes the top thereof. The planarization layer 107 may be configured in various forms, and may be formed of an organic insulating film such as BCB (Benzocyclobutene) or acrylic (Acryl), or an inorganic insulating film such as a silicon nitride film (SiNx) or a silicon oxide film (SiOx), Various modifications are possible, such as being formed in a single layer or may be configured in double or multiple layers.

The organic light emitting device may have a form in which the first electrode 112 , the organic light emitting layer 114 , and the second electrode 116 are sequentially disposed. That is, the organic light emitting device includes a first electrode 112 formed on the planarization layer 107 , an organic light emitting layer 114 positioned on the first electrode 112 , and a second electrode ( 116) can be configured.

The first electrode 112 is electrically connected to the drain electrode 108 of the driving TFT through a contact hole. When the organic light emitting diode display 100 is a top emission type, the first electrode 112 may be made of an opaque conductive material having high reflectivity. For example, the first electrode 112 may be formed of silver (Ag), aluminum (Al), gold (Au), molybdenum (Mo), tungsten (W), chromium (Cr), or an alloy thereof. . The first electrode 112 may be an anode of an organic light emitting diode.

The bank 110 is formed in the remaining area except for the light emitting area. Accordingly, the bank 110 has a bank hole exposing the first electrode 112 corresponding to the emission region. The bank 110 may be made of an inorganic insulating material such as a silicon nitride film (SiNx) or a silicon oxide film (SiOx), or an organic insulating material such as BCB, an acrylic resin, or an imide resin.

An organic light emitting layer 114 is located on the first electrode 112 exposed by the bank 110 . The organic light emitting layer 114 may include an emission layer (EL), an electron injection layer (EIL), an electron transport layer (ETL), a hole transport layer (HTL), a hole injection layer (HIL), and the like. Each of these layers may be implemented independently, or may be implemented as one or more integration layers in which at least two functions are integrated. The organic light emitting layer may have a structure of a single light emitting layer emitting one light, or a structure of emitting white light by being composed of a plurality of light emitting layers.

The second electrode 116 is positioned on the organic light emitting layer 114 . When the organic light emitting diode display 100 is a top emission type, the second electrode 116 is a transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). By being formed of a material, light generated from the organic light emitting layer 114 is emitted to the upper portion of the second electrode 116 . The second electrode 116 may be a cathode of an organic light emitting diode.

The encapsulation layer 120 is positioned on the second electrode 116 . The encapsulation layer 120 prevents the penetration of oxygen and moisture from the outside in order to prevent oxidation of the light emitting material and the electrode material. When the organic light emitting device is exposed to moisture or oxygen, a pixel shrinkage phenomenon in which the light emitting area is reduced may occur or a dark spot may occur in the light emitting area. The encapsulation layer is composed of an inorganic film made of glass, metal, aluminum oxide (AlOx) or silicon (Si)-based material, or the organic film 122 and the inorganic films 121-1 and 121-2. This alternately stacked structure may be used. At this time, the inorganic layers 121-1 and 121-2 serve to block the penetration of moisture or oxygen, and the organic layer 122 serves to planarize the surfaces of the inorganic layers 121-1 and 121-2. do. When the encapsulation layer is formed as a multi-layered thin film layer, the movement path of moisture or oxygen becomes longer and more complicated than in the case of a single layer, making it difficult for moisture/oxygen to penetrate to the organic light emitting diode.

The barrier film 140 may be positioned on the encapsulation layer 120 to encapsulate the entire base layer 101 . The barrier film 140 may be a retardation film or an optical isotropic film. An organic or inorganic film may be further positioned on the upper or lower surface of the barrier film 140 to block the penetration of external moisture or oxygen.

An adhesive layer 145 may be positioned between the barrier film and the encapsulation layer 120 . The adhesive layer 145 adheres the encapsulation layer 120 and the barrier film 140 . The adhesive layer 145 may be a thermally curable or naturally curable adhesive. For example, the adhesive layer may be made of a material such as a barrier pressure sensitive adhesive (B-PSA).

A touch panel (film), a polarizing film, a top cover, and the like may be further positioned on the barrier film 140 .

Although the pixel circuit and the light emitting device are not disposed in the non-display area I/A, the base layer 101 and the organic/inorganic functional layers 130 , 105 , 107 120 , etc. may be present. In addition, materials used to form the display area A/A may be disposed in the non-display area I/A for different purposes. For example, the same metal 104' as the gate electrode of the display area TFT, or the same metal 108' as the source/drain electrode may be disposed in the non-display area I/A for the conductive wire or electrode. Furthermore, the same metal 112 ′ as one electrode (eg, an anode) of the organic light emitting diode may be disposed in the non-display area I/A for a conductive wire and an electrode.

The base layer 101 , the buffer layer 130 , the gate insulating layer 105 , and the planarization layer 107 of the non-display area I/A are the same as those described in the display area A/A. The dam 190 is a blocking structure that controls the flowable organic layer 122 of the encapsulation layer 120 from spreading too far into the non-display area I/A. Various circuits and electrodes/wires disposed in the non-display area I/A may be made of the gate metal 104 ′ and/or the source/drain metal 108 ′. In a specific section, the source/drain metal 108 ′ forms a jumping structure with the gate metal 104 ′ and functions as a single conductor. The gate metal 104' is formed of the same material as the gate electrode of the TFT in the same process, and the source/drain metal 108' is formed of the same material as the source/drain electrode of the TFT in the same process.

For example, the source/drain metal may be used as a power supply (eg, a low-level power supply (VSS) wiring 108 ′. In this case, the power wiring 108 ′ is connected to the connection metal layer 112 ′, and the organic light emitting diode is formed. The cathode 116 of the diode may be supplied with power through connection with the source/drain metal 108' and the connection metal layer 112'. The connection metal layer 112' is the power wiring 108'. ) and may extend along the sidewall of the outermost planarization layer 107 to contact the cathode 116 on the planarization layer 107. The connecting metal layer 112' is the anode ( 112) and may be a metal formed in the same process with the same material.

3A and 3B are cross-sectional views illustrating color differences occurring in some regions of a display device.

In recent years, the design of the display device has changed in various ways, and accordingly, the active area is implemented in various shapes, so that the display area is introduced in various shapes in addition to the existing uniform rectangular shape. One of them is the shape of the display area in which the corners are rounded. (So-called round shape) However, the inventors of the present invention have discovered that in a display device having a display area having a singular shape instead of a quadrangle, some problems occur if the specificity is not taken into account. One of such problems is a color difference appearing at a corner of a display area designed to be different.

3A is a diagram illustrating the color difference. The inventors found that in a display device in which the display area A/A has a heterogeneous design (eg, rounded corner) as shown in the drawing, a difference in color occurs at the boundary between the display area and the non-display area. This color difference was better recognized when the display device was not driven or when the display area expressed a dark gray level.

As a result of studying the above phenomenon, the inventors found that the specific region Z having a color difference often has a stack structure different from that of the surrounding region, resulting in the above phenomenon in many cases. That is, it was analyzed that the color difference was caused by different properties of reflecting external light incident on the display device because the upper material of the specific region Z was different from the surrounding region. In particular, when the upper material of the display area (eg, the anode 112) and the upper material of the non-display area (eg, the power wiring 112') are used for different purposes, the greater the distance therebetween, the greater the There were many cases where there was a color difference. The inventors recognized the problem as described above and devised a structure capable of uniformly maintaining the visibility of a display device having a heterogeneous display area.

4A and 4B are diagrams illustrating a display device according to an exemplary embodiment of the present specification.

In order to solve the problem described in FIG. 3 , the inventors have devised an organic light emitting display device having a uniform color by newly designing the structure of the outer portion of the display area. Such a structure will be described below with reference to FIGS. 4A and 4B. FIG. 4A is an enlarged view of area A of FIG. 1 , and FIG. 4B is a cross-sectional view taken along line II-II' of FIG. 4A . Since the display area A/A of FIG. 4A is substantially the same as the display area A/A of FIGS. 1 and 2 , a redundant description thereof will be omitted. On the other hand, since the non-display area I/A of FIG. 4A further includes a special structure different from the non-display area I/A described with reference to FIG. 2 , the description will be focused on this.

In the embodiment illustrated in FIGS. 4A and 4B , the reflective layer 412 ″ provided to compensate for a color difference appearing outside the display area (eg, near a corner) can be seen. The reflective layer 412 ″ functions as a structure to compensate for a color difference caused by non-uniform reflection of external light. As described above, the color difference is found near the boundary between the display area and the non-display area, and is often caused by a stack structure of the corresponding area different from the surrounding area. That is, the color difference generally occurs because the upper material of a specific area is different from the surrounding area, and thus the property of reflecting the incident external light is also different. Therefore, if the upper layer structure is the same as the entire display device by arranging the reflective layer 412 ″ having the same physical properties as the surrounding region to correspond to the region (Z in FIG. 3) where the color difference occurs, external light is reflected The characteristics may also be uniform as a whole.

Accordingly, an organic light emitting diode display according to an exemplary embodiment of the present specification includes: a base layer 401 having a display area A/A for displaying an image and a non-display area I/A surrounding the display area; The reflective layer 412 ″ may be provided to compensate for a color difference between the display area A/A and the non-display area I/A. The display area A/A includes a pixel and a pixel circuit associated with the pixel, and the non-display area I/A surrounds the display area A/A.

The reflective layer 412 ″ is located near the boundary of the display area A/A, and in particular, between the low-level power supply (VSS) wiring and the light emitting device (eg, organic light emitting diode) of the display area A/A. can be located in The reflective layer 412 ″ may be the same material on the same layer as the uppermost reflective material of the display area A/A. That is, the reflective layer 412 ″ may be the same material as the uppermost reflective material (metal) that has the greatest effect to reflect external light incident on the display area.

For example, the uppermost reflective material may be the anode 412 of the organic light emitting diode. This is because, when the display device is a top emission type, a reflective metal (eg, Ag) is included in the anode. Accordingly, the reflective layer 412 ″ may be the same material layer formed in the same process as the anode of the organic light emitting diode in the display area. In this case, the reflective layer 412 ″ may be positioned between the anode 412 of the display area A/A and the connection metal layer 412 ′ of the non-display area I/A. The connection metal layer 412 ′ is a portion of a low level power supply (VSS) wiring, and connects the other portion 408 ′ of the low level power wiring and the cathode 416 of the organic light emitting diode. The low-level power wirings 408 ′ and 412 ′ may extend from a connection interface (eg, a PAD, etc.) to the display region (or pixel circuit) through the non-display region. have. The connection metal layer 412 ′ is in contact with another metal layer 408 ′ constituting the low-level power wiring, and extends along the outermost sidewall of the planarization layer 407 , and the cathode 416 is disposed on the planarization layer 407 . ) can be in contact with The other metal layer 408' may be formed of the same material as the source/drain electrodes of the TFT in the same process.

One electrode 412 of the organic light emitting diode is a first anode metal; The connecting metal layer 412' is formed of a second anode metal; If the reflective layer 412 ″ located between the first anode metal and the second anode metal is referred to as a third anode metal, the display device according to the embodiment of the present specification includes one electrode of the organic light emitting diode. a first anode metal 412 to form, a second anode metal 412' to form a portion of a conducting wire that transmits a low level power (VSS) to the organic light emitting diode; and a third anode metal 412 ″ positioned between the first anode metal and the second anode metal.

The third anode metal 412 ″ is provided to compensate for a color difference appearing outside the display area A/A. The third anode metal 412 ″ is isolated without being connected to the first anode metal 412 and the second anode metal 412 ′. In addition, the third anode metal 412'', ie, the reflective layer 412'', is electrically floating without being connected to any power source.

Through the structure as described above, in the organic light emitting display device according to the embodiment of the present specification, color difference in the outer portion of the display area is prevented, so that uniformity and aesthetics can be further improved.

Although the embodiments of the present specification have been described in detail with reference to the accompanying drawings, the present specification is not necessarily limited to these embodiments, and various modifications may be made within the scope without departing from the technical spirit thereof. Accordingly, the embodiments disclosed in the present specification are for explanation rather than limiting the technical spirit of the present invention, and the scope of the technical spirit of the present invention is not limited by these embodiments. Each feature of the various embodiments of the present invention may be partially or wholly combined or combined with each other, and may be technically variously linked and operated by those skilled in the art, and each embodiment may be implemented independently of each other or together in a related relationship. may be carried out. The protection scope of the present invention should be construed by the following claims, and all technical ideas within the equivalent range should be construed as being included in the scope of the present invention.

Claims (10)

a base layer having a display area for displaying an image and a non-display area surrounding the display area;
a reflective layer provided to compensate for a color difference appearing at a boundary between the display area and the non-display area;
The reflective layer is positioned between the anode of the organic light emitting diode in the display area and the connecting metal layer in the non-display area,
The connection metal layer is a portion of a low-level power supply (VSS) wiring, and connects the other portion of the low-level power wiring to a cathode of the organic light emitting diode. The method of claim 1,
The reflective layer is positioned between the light emitting element in the display area and a low-level power supply (VSS) wiring in the non-display area. The method of claim 1,
The reflective layer is an organic light emitting display device of the same material on the same layer as the uppermost reflective material of the display area. The method of claim 1,
The reflective layer is made of the same material as the anode of the organic light emitting diode in the display area. The method of claim 1,
a planarization layer protecting the thin film transistor of the display area and planarizing an upper portion thereof;
The connection metal layer is in contact with the low-level power wiring, extends along an outermost sidewall of the planarization layer, and contacts the cathode at an upper portion of the planarization layer. 5. The method of claim 4,
The reflective layer is in an electrically floating state. a first anode metal forming one electrode of the organic light emitting diode;
a second anode metal forming a portion of a wire for transmitting low-level power to the organic light emitting diode; and
a third anode metal positioned between the first anode metal and the second anode metal;
The second anode metal connects the other portion of the conducting wire that transmits low-level power to the cathode of the organic light emitting diode. 8. The method of claim 7,
The third anode metal is provided to compensate for a color difference appearing outside the display area. 8. The method of claim 7,
The third anode metal is not connected to the first anode metal and the second anode metal and is isolated from the display device. 8. The method of claim 7,
The third anode metal is in an electrically floating state.

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