KR20210051345A - Display device - Google Patents

Abstract

The present invention relates to a display device. According to one embodiment of the present invention, the display device includes a base film, a conductive layer on the base film, an adhesive layer on the conductive layer, a substrate on the adhesive layer, and a light emitting element on the substrate, wherein the conductive layer includes a first conductive polymer material and a second conductive polymer material. Accordingly, the conductive layer is disposed under the substrate to effectively remove the residual charge of the substrate.

Description

Display device {DISPLAY DEVICE}

The present invention relates to a display device, and more particularly, to a display device for improving discharge characteristics of a substrate.

In recent years, as the era of full-fledged information is entered, the field of displays that visually express electrical information signals has rapidly developed, and in response to this, various display devices with excellent performance of thinner, lighter, and low power consumption (Display Apparatus) Is being developed. Specific examples of such a display device include a liquid crystal display (LCD), an organic light emitting display (OLED), and an electroluminescence display such as a quantum dot light emitting display (QLED).

In addition, in recent years, development of a flexible display device such as a bendable display device or a foldable display device is in progress. The flexible display device may be implemented by forming a display unit and a wiring on a flexible substrate such as plastic, which is a flexible material, and applying a back film to the rear surface of the substrate to protect the flexible display panel. The flexible display device can display an image even if it is bent like a paper, and when folded, it can be carried easily and a large screen can be realized when it is unfolded. Accordingly, the flexible display device can be applied not only to mobile devices such as mobile phones, e-books, and electronic newspapers, but also to various fields such as televisions and monitors.

The problem to be solved by the present invention is to provide a display device capable of easily discharging residual charges of a substrate to the outside by a conductive layer.

Another problem to be solved by the present invention is to provide a display device capable of improving reliability and display quality by improving discharge characteristics of a substrate.

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

A display device according to an embodiment of the present invention includes a base film, a conductive layer on the base film, an adhesive layer on the conductive layer, a substrate on the adhesive layer, and a light emitting device on the substrate, wherein the conductive layer is a first conductive polymer material and a second conductive material. Contains polymeric materials.

A display device according to an embodiment of the present invention includes a base film, a back film including a conductive layer and an adhesive layer, a substrate on the adhesive layer, a barrier layer on the substrate, and a light emitting device on the barrier layer, and the conductive layer is a hole transport material and Contains electron transport materials.

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

In the present invention, by disposing a conductive layer under the substrate, it is possible to effectively remove the residual charge on the substrate.

The present invention can improve the reliability and display quality of a display device by effectively discharging residual charges by improving discharge characteristics of a substrate through a conductive layer.

The effects according to the present invention are not limited by the contents exemplified above, and more various effects are included in the present invention.

1 is a plan view of a display device according to an exemplary embodiment of the present invention.
2 is a cross-sectional view of the display device according to II-II' of FIG. 1.
3 is a comparison of LUMO and HOMO of a first conductive polymer material and a second conductive polymer material of a conductive layer according to an embodiment of the present invention.
4 is a cross-sectional view of a display device according to another exemplary embodiment of the present invention.
5 is a cross-sectional view of a substrate structure for measuring half-life.

Advantages and features of the present invention, and a method of achieving them will become apparent with reference to the embodiments described below in detail together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in a variety of different shapes, only these embodiments are intended to complete the disclosure of the present invention, and common knowledge in the technical field to which the present invention pertains. It is provided to completely inform the scope of the invention to those who have, and the invention is only defined by the scope of the claims.

The shapes, areas, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of the present invention are exemplary, and thus the present invention is not limited to the illustrated matters. The same reference numerals refer to the same elements throughout the specification. In addition, in describing the present invention, when it is determined that a detailed description of related known technologies may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted. When'include','have','consists of' and the like mentioned in the present invention are used, other parts may be added unless'only' is used. In the case of expressing the constituent elements in the singular, it includes the case of including the plural unless specifically stated otherwise.

In interpreting the constituent elements, it is interpreted as including an error range even if there is no explicit description.

In the case of a description of the positional relationship, for example, if the positional relationship of two parts is described as'upper','upper of','lower of','next to','right' Or, unless'direct' is used, one or more other parts may be located between the two parts.

When an element or layer is referred to as “on” another element or layer, it includes all cases in which another layer or another element is interposed directly on or in the middle of another element.

Also, the first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one component from another component. Accordingly, the first constituent element mentioned below may be a second constituent element within the technical idea of the present invention.

The same reference numerals refer to the same elements throughout the specification.

The area 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 area and thickness of the illustrated component.

Each of the features of the various embodiments of the present invention can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each of the embodiments may be independently implemented with respect to each other or can be implemented together in an association relationship. May be.

Hereinafter, the present invention will be described with reference to the drawings.

1 is a plan view of a display device according to an exemplary embodiment of the present invention. 2 is a cross-sectional view of a display device according to II-II' of FIG. 1. 3 is a comparison of LUMO and HOMO of a first conductive polymer material and a second conductive polymer material of a conductive layer according to an embodiment of the present invention.

1 and 2, the display device 100 includes a back film 110, a substrate 120, a transistor 130, a light emitting device 140, and an encapsulation 150.

First, referring to FIG. 1, the substrate 120 is a substrate for supporting and protecting various components of the display device 100. The substrate 120 may be made of a plastic material having flexibility. For example, the substrate 120 may be made of polyimide (PI), but is not limited thereto.

The substrate 120 includes a display area A/A and a non-display area N/A.

The display area AA is disposed at the center of the substrate 120 and may be an area in which an image is displayed on the display device 100. A display element and various driving elements for driving the display element may be disposed in the display area AA. For example, the display device may include a light emitting device 140 including a first electrode 141, a light emitting layer 142, and a second electrode 143. In addition, various driving elements such as a transistor, a capacitor, and a wiring for driving the display element may be disposed in the display area AA.

A plurality of pixels PX may be included in the display area AA. The plurality of pixels PX may be defined as an intersection region of a plurality of gate wires disposed in a first direction and a plurality of data wires disposed in a second direction different from the first direction. Here, the first direction may be the horizontal direction of FIG. 1, and the second direction may be the vertical direction of FIG. 1, but is not limited thereto. Each of the plurality of pixels PX may include a plurality of sub-pixels that emit light having different wavelengths. For example, the plurality of sub-pixels may include a red sub-pixel, a green sub-pixel, a blue sub-pixel, and a white sub-pixel, but is not limited thereto.

The pixel PX is a minimum unit constituting a screen, and each of the plurality of pixels PX may include a light emitting element 140 and a driving element. In this case, the driving element may include a switching transistor, a driving transistor, or the like. The driving element may be electrically connected to a signal line such as a gate line or a data line connected to a gate driver or a data driver disposed in the non-display area NA. A more detailed structure of the pixel PX will be described later with reference to FIG. 2.

The non-display area NA is disposed in the circumferential area of the substrate 120 and may be an area in which an image is not displayed. The non-display area NA may be disposed to surround the display area AA. Various components for driving the plurality of pixels PX disposed in the display area AA may be disposed in the non-display area NA. For example, a driving IC supplying signals for driving the plurality of pixels PX, a driving circuit, a signal line, a flexible film, and the like may be disposed. In this case, the driving IC may include a gate driver, a data driver, or the like. The gate driver and the data driver may be implemented with a thin film transistor (TFT). The driving IC and driving circuit can be arranged in a GIP (Gate In Panel) method, COF (Chip On Film) method, TAB (Tape Automated Bonding) method, TCP (Tape Carrier Package) method, COG (Chip On Glass) method, etc. have.

Hereinafter, one pixel PX disposed in the display area AA of the display device 100 will be described in more detail with reference to FIG. 2.

Referring to FIG. 2, a barrier layer 121 is disposed on a substrate 120. The barrier layer 121 may improve adhesion between layers formed on the barrier layer 121 and the substrate 120, and may block an alkali component, etc., leaking out from the substrate 120. The barrier layer 121 may be formed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx), or a multiple layer of silicon nitride (SiNx) and silicon oxide (SiOx).

The transistor 130 may be disposed on the barrier layer 121 to drive the light emitting device 140. The transistor 130 includes an active layer 131, a gate electrode 132, a source electrode 133, and a drain electrode 134. The transistor 130 illustrated in FIG. 2 is a driving transistor, and is a thin film transistor having a top gate structure in which the gate electrode 132 is disposed on the active layer 131. However, the present invention is not limited thereto, and the transistor 130 may be implemented as a thin film transistor having a bottom gate structure.

The active layer 131 of the transistor 130 is disposed on the barrier layer 121. The active layer 131 is a region in which a channel is formed when the transistor 130 is driven. The active layer 131 may be formed of an oxide semiconductor, amorphous silicon (a-Si), polycrystalline silicon (poly-Si), or an organic semiconductor. have.

A gate insulating layer 122 is disposed on the active layer 131. The gate insulating layer 122 may be formed of a single layer of inorganic silicon nitride (SiNx) or silicon oxide (SiOx), or a multilayer of silicon nitride (SiNx) or silicon oxide (SiOx). In the gate insulating layer 122, a contact hole for each of the source electrode 133 and the drain electrode 134 to contact each of the source region and the drain region of the active layer 131 is formed. The gate insulating layer 122 may be formed over the entire surface of the substrate 120 as shown in FIG. 2, or may be patterned to have the same width as the gate electrode 132, but is not limited thereto.

The gate electrode 132 is disposed on the gate insulating layer 122. The gate electrode 132 is disposed on the gate insulating layer 122 to overlap the channel region of the active layer 131. The gate electrode 132 is a variety of metal materials, for example, molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and It may be any one of copper (Cu), an alloy of two or more, or a multilayer thereof.

An interlayer insulating layer 123 is disposed on the gate electrode 132. The interlayer insulating layer 123 may be formed of a single layer of inorganic silicon nitride (SiNx) or silicon oxide (SiOx), or a multilayer of silicon nitride (SiNx) or silicon oxide (SiOx). In the interlayer insulating layer 123, a contact hole for each of the source electrode 133 and the drain electrode 134 to contact each of the source region and the drain region of the active layer 131 is formed.

The source electrode 133 and the drain electrode 134 are disposed on the interlayer insulating layer 123. The source electrode 133 and the drain electrode 134 are electrically connected to the active layer 131 through contact holes of the gate insulating layer 122 and the interlayer insulating layer 123. The source electrode 133 and the drain electrode 134 are various metal materials, for example, molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), It may be made of any one of neodymium (Nd) and copper (Cu), or may be an alloy of two or more, or a multilayer thereof.

In FIG. 2, for convenience of description, only a driving transistor is illustrated among the various transistors 130 included in the light emitting display device 100, but other transistors such as a switching transistor may also be disposed.

Referring to FIG. 2, a passivation layer 124 for protecting the transistor 130 is disposed on the transistor 130. A contact hole for exposing the drain electrode 134 of the transistor 130 is formed in the passivation layer 124. In FIG. 2, it is shown that a contact hole for exposing the drain electrode 134 is formed in the passivation layer 124, but a contact hole for exposing the source electrode 133 may be formed. The passivation layer 124 may be formed of a single layer of silicon nitride (SiNx) or silicon oxide (SiOx), or a multiple layer of silicon nitride (SiNx) or silicon oxide (SiOx). However, the passivation layer 124 may be omitted depending on the embodiment.

An overcoat layer 125 for planarizing the top of the transistor 130 is disposed on the passivation layer 124. A contact hole for exposing the drain electrode 134 of the transistor 130 is formed in the overcoat layer 125. In FIG. 2, it is shown that a contact hole for exposing the drain electrode 134 is formed in the overcoat layer 125, but a contact hole for exposing the source electrode 133 may be formed. The overcoat layer 125 is an acrylic resin, an epoxy resin, a phenol resin, a polyamide resin, a polyimide resin, an unsaturated polyester resin, and a polyphenylene resin. polyphenylene) resin, polyphenylene sulfide resin, benzocyclobutene, and photoresist, but is not limited thereto.

Referring to FIG. 2, the light emitting device 140 is disposed on the overcoat layer 125. The light-emitting element 140 is formed on the over-coating layer 125 and electrically connected to the drain electrode 134 of the transistor 130 and the first electrode 141 and the light-emitting layer 142 disposed on the first electrode 141 And a second electrode 143 formed on the emission layer 142. Here, the first electrode 141 may be an anode electrode, and the second electrode 143 may be a cathode electrode.

The first electrode 141 is disposed on the overcoat layer 125 and is electrically connected to the drain electrode 134 through a contact hole formed in the passivation layer 124 and the overcoat layer 125. The first electrode 141 may be made of a conductive material having a high work function to supply holes to the emission layer 142. For example, the first electrode 141 may include Indium Tin Oxide (ITO), Indium Zinc Oxide (IZO), Indium Tin Zinc Oxide (ITZO), and zinc oxide ( Zinc Oxide, ZnO) and tin oxide (Tin Oxide, TO)-based transparent conductive oxide may be formed, but is not limited thereto.

Meanwhile, when the display device 100 is a top emission type display device, the light emitting element 140 is also configured as a top emission type. In the case of the top emission method, a reflective layer for reflecting light emitted from the light emitting layer 142 toward the second electrode 143 may be disposed under the first electrode 141. The reflective layer may be made of a material having excellent reflectivity such as silver (Ag) or a silver alloy, but is not limited thereto.

In FIG. 2, the first electrode 141 is shown to be electrically connected to the drain electrode 134 of the transistor 130 through a contact hole. However, the first electrode 141 is connected to the drain electrode 134 of the transistor 130 through a contact hole. The electrode 141 may be configured to be electrically connected to the source electrode 133 of the transistor 130 through a contact hole.

The bank 126 is disposed on the first electrode 141 and the overcoat layer 125. The bank 126 may cover a part of the first electrode 141 of the light emitting device 140 to define a light emitting area. The bank 126 may be made of an organic material. For example, the bank 126 may be made of a polyimide resin, an acrylic resin, or a benzocyclobutene resin, but is not limited thereto.

The emission layer 142 is disposed on the first electrode 141. The emission layer 142 is a layer for emitting light of a specific color, and may include one of a red emission layer, a green emission layer, a blue emission layer, and a white emission layer. In addition, the light emitting layer 142 may further include various layers such as a hole transport layer, a hole injection layer, a hole blocking layer, an electron injection layer, an electron blocking layer, an electron transport layer, and the like.

The second electrode 143 is disposed on the emission layer 142. The second electrode 143 supplies electrons to the emission layer 142. The second electrode 143 may be made of a conductive material having a low work function. For example, the second electrode 143 may be made of one or more selected from the group consisting of opaque conductive metals such as magnesium (Mg), silver (Ag), aluminum (Al), calcium (Ca), and alloys thereof. have. Alternatively, the second electrode 143 is Indium Tin Oxide (ITO), Indium Zin Oxide (IZO), Indium Tin Zinc Oxide (ITZO), Zinc Oxide, ZnO) and tin oxide (Tin Oxide, TO)-based transparent conductive oxide or ytterbium (Yb) alloy may be formed. Alternatively, the second electrode 143 may be made of a very thin metal material. However, the second electrode 143 is not limited to the above-described materials.

On the other hand, when the display device 100 is a top emission type display device, the second electrode 143 is formed so that the light emitted from the light emitting layer 142 passes through the second electrode 143 and is emitted to the outside. It may have a transparent or translucent property.

Referring to FIG. 2, the encapsulation part 150 is disposed on the light emitting device 140. For example, the encapsulation part 150 is disposed on the second electrode 143 to cover the light emitting element 140. The encapsulation unit 150 protects the light emitting element 140 from moisture penetrating from the outside of the light emitting display device 100. The encapsulation part 150 includes a first encapsulation layer 151, a foreign material cover layer 152 and a second encapsulation layer 153.

The first encapsulation layer 151 is disposed on the second electrode 143 to suppress penetration of moisture or oxygen. The first encapsulation layer 151 may be formed of an inorganic material such as silicon nitride (SiNx), silicon oxynitride (SiNxOy), or aluminum oxide (AlyOz), but is not limited thereto.

The foreign material cover layer 152 is disposed on the first encapsulation layer 151 to planarize the surface. In addition, the foreign material cover layer 152 may cover foreign materials or particles that may occur during a manufacturing process. The foreign material cover layer 152 may be formed of an organic material such as silicon oxycarbon (SiOxCz), acrylic or epoxy resin, but is not limited thereto.

The second encapsulation layer 153 is disposed on the foreign material cover layer 152 and, like the first encapsulation layer 151, can suppress the penetration of moisture or oxygen. The second encapsulation layer 153 may be made of an inorganic material such as silicon nitride (SiNx), silicon oxynitride (SiNxOy), silicon oxide (SiOx), or aluminum oxide (AlyOz), but is not limited thereto. The second encapsulation layer 153 may be made of the same material as the first encapsulation layer 151 or may be made of a different material.

Referring to FIG. 2, the back film 110 is disposed under the substrate 120. The back film 110 may include a base film 111, a conductive layer 112 and an adhesive layer 113. The back film 110 may protect the substrate 120. That is, the back film 110 may block moisture that may penetrate into the rear surface of the substrate 120. In addition, since the back film 110 includes the conductive layer 112, electric charges and static electricity accumulated on the substrate 120 can be easily discharged to the outside. Meanwhile, in FIG. 2, the base film 111, the conductive layer 112 and the adhesive layer 113 are defined as constituent elements of the back film 110, but the base film 111, the conductive layer 112, and the adhesive layer 113 ) Each may be a separate and independent component.

The base film 111 may be disposed to support the substrate 120. The base film 111 may supplement the rigidity of the substrate 120 by supporting the substrate 120. The base film 111 may be made of a plastic material such as polyimide or polyethylene terephthalate (PET), but is not limited thereto.

When the substrate 120 is made of a plastic material such as polyimide, a separate component for supporting the substrate 120 may be required due to its flexible property. Accordingly, during the manufacturing process of the display device 100, a support substrate made of glass is disposed under the substrate 120, and after the manufacturing process is completed, the back film 110 or the base film 111 is placed under the substrate 120. ) Can be placed. Specifically, in order to support the substrate 120, a support substrate made of glass is disposed under the substrate 120 to proceed with the manufacturing process of the display device 100, and after the manufacturing process is completed, the support substrate is separated and released. I can. In addition, after the support substrate is released, the back film 110 or the base film 111 may be disposed under the substrate 120 to support the substrate 120.

The adhesive layer 113 may adhere the back film 110 and the substrate 120. That is, the adhesive layer 113 may adhere the base film 111 on which the conductive layer 112 is formed to the substrate 120. The adhesive layer 113 may be an acrylic adhesive, but is not limited thereto.

The conductive layer 112 may be disposed between the base film 111 and the substrate 120. In particular, the conductive layer 112 may be disposed between the base film 111 and the adhesive layer 113. Since the conductive layer 112 serves as a ground, residual charges accumulated in the substrate 120 can be easily discharged to the outside. In this case, the conductive layer 112 may be in an electrically floating state.

The conductive layer 112 may include a conductive material. The conductive layer 112 may be formed by coating or depositing a conductive material on the base film 111. Specifically, the conductive layer 112 is formed as a single layer, and may include a first conductive polymer material and a second conductive polymer material. The first conductive polymer material may be a hole transporting material (HTM), and the second conductive polymer material may be an electron transporting material (ETM). Meanwhile, in the present invention, the conductive layer 112 has been described on the basis of including one hole transport material (HTM) and one electron transport material (ETM), but is not limited thereto. That is, each of the hole transport material (HTM) and the electron transport material (ETM) included in the conductive layer 112 may include one or more different materials.

In general, the substrate is made of a polymer material having flexible properties such as polyimide. Since such a material has high resistance and low discharge characteristics, charges generated by driving elements disposed on the substrate or static electricity generated during a process cannot be discharged to the outside and may accumulate in the substrate. Residual charges accumulated in the substrate may cause unwanted parasitic capacitance or electric field to be formed, resulting in deterioration of driving characteristics of the display device, deterioration of image quality, and generation of afterimages. That is, the quality and reliability of the display device may be deteriorated due to residual charges accumulated in the substrate.

The display device 100 according to the present invention includes a conductive layer 112 disposed between the substrate 120 and the base film 111. The residual charge accumulated on the substrate 120 by the conductive layer 112 can be easily discharged to the outside. Accordingly, discharge characteristics of the substrate 120 are improved, and reliability and display quality of the display device 100 may be improved.

Specifically, the polyimide constituting the substrate 120 includes a polyimide chain having conjugation. Inside the polyimide chain, an electron donor-acceptor interaction between a diamine unit serving as an electron donor and a diimide unit serving as an electron acceptor. -acceptor interaction) can be done. The electron donor-acceptor interaction between the diamine unit and the diimide unit may transfer residual charges accumulated in the substrate 120 to the outside. However, since the resistance of the polyimide itself is high, the effect of discharging residual charges simply due to an electron donor-acceptor interaction may be insignificant. Accordingly, by disposing the conductive layer 112 under the substrate 120, the electron donor-acceptor interaction of the substrate 120 may be promoted.

More specifically, the conductive layer 112 may include a first conductive polymer material including a hole transport material (HTM) and a second conductive polymer material including an electron transport material (ETM). Accordingly, energy may be generated by a combination of holes and electrons, which is an interaction between the first conductive polymer material and the second conductive polymer material. The generated energy is used for charge transfer due to the electron donor-acceptor interaction of the substrate 120, thereby improving discharge characteristics of the substrate 120.

Referring to FIG. 3, a hole transport material (HTM), which is a first conductive polymer material, has a higher LUMO (Lowest Unoccupied Molecular Orbital) energy level and a Highest Occupied Molecular Orbital (HOMO) compared to an electron transport material (ETM) that is a second conductive polymer material. ) Can have an energy level. In the conductive layer 112, holes are transported using the HOMO energy level of the hole transport material (HTM), and electrons may be transported using the LUMO energy level of the electron transport material (ETM). Accordingly, from the viewpoint of movement of holes and electrons, the HOMO energy level of the conductive layer 112 is the HOMO energy level of the hole transport material (HTM), and the LUMO energy level of the conductive layer 112 is the electron transport material (ETM). LUMO energy level. In the conductive layer 112, holes and electrons are combined to generate excitons, and energy in the form of light is generated when the generated excitons fall from an excited state to a ground state. I can. The energy generated at this time may correspond to a difference (ΔE) between the HOMO energy level of the hole transport material HTM and the LUMO energy level of the electron transport material ETM. In addition, the energy in the form of light described above may be energy in a longer wavelength region than visible light.

As such, energy in the form of light may be generated in the conductive layer 112 by the interaction between the first conductive polymer material and the second conductive polymer material. Energy in the form of light generated from the conductive layer 112 may be transferred to the substrate 120. In this case, the polyimide of the substrate 120 may have photoelectric sensitivity. Accordingly, energy in the form of light generated from the conductive layer 112 may be transferred to the diamine unit and the diimide unit of the substrate 120 to maximize the electron donor-acceptor interaction. In other words, the residual charge of the substrate 120 can be effectively discharged by the energy in the form of light generated from the conductive layer 112.

The first conductive polymer material is m-MTDATA(4,4',4''-tris[(3-methylphenyl)phenylamino]triphenylamine) or NPB(N,N'-Bis(naphthalen-1-yl)-N,N '-Bis(phenyl)benzidine) may be included. The second conductive polymer material is B3PYMPM(4,6-Bis(3,5-di-3-pyridinylphenyl)-2-methylpyrimidine) or TPBi(2,2',2''-(1,3,5-benzinetriyl) -tris(1-phenyl-1-H-benzimidazole) More preferably, when the first conductive polymer material is m-MTDATA, the second conductive polymer material may be B3PYMPM. When the first conductive polymer material is NPB, the second conductive polymer material may be TPBi, but this does not limit the present invention, which will be described in more detail with reference to Table 2 to be described later.

The content of the first conductive polymer material in the conductive layer 112 may be twice or more than the content of the second conductive polymer material. If the content of the first conductive polymer material is less than twice the content of the second conductive polymer material, the mobility of the conductive layer 112 is lowered, and thus holes and electrons may not be sufficiently bonded. Specifically, the hole transport material (HTM), which is the first conductive polymer material, may have a relatively faster mobility than the electron transport material (ETM), which is the second conductive polymer material. Therefore, when the content of the first conductive polymer material is more than twice the content of the second conductive polymer material, the conductive layer 112 maintains a relatively fast mobility, and holes and electrons can be sufficiently bonded. This will be described in more detail with reference to Table 3 to be described later.

4 is a cross-sectional view of a display device according to another exemplary embodiment of the present invention. The display device 400 of FIG. 4 is substantially the same as that of the display device 100 of FIG. 1 except for the structure of the conductive layer 412, and thus, redundant descriptions are omitted.

Referring to FIG. 4, the conductive layer 412 includes a first conductive layer 412a and a second conductive layer 412b. Specifically, the first conductive layer 412a may be disposed on the base film 111 and the second conductive layer 412b may be disposed on the first conductive layer 412a.

Each of the first conductive layer 412a and the second conductive layer 412b may include different materials. For example, the first conductive layer 412a includes a first conductive polymer material that is a hole transport material (HTM), and the second conductive layer 412b includes a second conductive polymer material that is an electron transport material (ETM). can do. However, the present invention is not limited thereto, and the first conductive layer 412a may include a hole transport material (HTM), and the second conductive layer 412b may include an electron transport material (ETM).

The first conductive polymer material may include m-MTDATA or NPB. The second conductive polymer material may include B3PYMPM or TPBi. More preferably, when the first conductive polymer material is m-MTDATA, the second conductive polymer material may be B3PYMPM. In addition, when the first conductive polymer material is NPB, the second conductive polymer material may be TPBi. However, this does not limit the present invention.

The display device 400 according to another exemplary embodiment of the present invention includes a first conductive layer 412a including a hole transport material (HTM) and a second conductive layer 412b including an electron transport material (ETM). It includes a conductive layer 412. Accordingly, energy may be generated by the combination of holes and electrons in the conductive layer 412. The residual charge of the substrate 120 is effectively discharged by the energy generated in the conductive layer 412, and discharge characteristics of the display device 400 may be improved.

5 is a cross-sectional view of a substrate structure for measuring half-life.

Referring to FIG. 5, the substrate structure 50 includes a base film 51, a conductive layer 52, an adhesive layer 53, a substrate 54, and a barrier layer 55. Here, the base film 51, the adhesive layer 53, the substrate 54, and the barrier layer 55 are the base film 111, the adhesive layer 113, the substrate 120, and the barrier layer 121 described in FIG. same. The substrate structure 50 according to the comparative example of Tables 1 to 3 to be described later and the substrate structure 50 according to the embodiment were configured differently only with the conductive layer 52, and all other than the conductive layer 52 may be configured identically. have.

Table 1 shows the properties according to the material of the conductive layer of the substrate structures according to Comparative Examples 1 to 4 and Example 1. In the case of Comparative Example 1, the conductive layer was omitted and an adhesive layer was formed directly on the base film. The conductive layers according to Comparative Examples 2, 3, and 4 were composed of one material, and the conductive layer material of Comparative Example 4 was composed of a hole transport material (HTM). In the case of Example 1, m-MTDATA, which is a hole transport material (HTM), and B3PYMPM, which is an electron transport material (ETM), were formed in a ratio of 3:1 as a conductive layer.

The half-life was measured using a Static Honestmeter (Shishido Electrostatic LTD, TYPE H-0110). Specifically, a substrate structure was placed on a stage in each of a general lighting (Light on) and a dark room (Light off), a voltage was applied to measure the saturation voltage, and then the time at which half of the saturation voltage was discharged was measured. At this time, the applied voltage was 10kV, the application time was 15 seconds, the frequency was 60Hz, the size of the substrate structure was 30X30mm, the distance between the substrate structure and the electrode was 15mm, and the measurement time was 300 seconds. The measurement results in Table 1 are average values of the results of three measurements for each of the same substrate structures.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Example 1 Conductive layer material Not included α-Si PEDOT/PSS TPD (HTM) m-MTDATA / B3PYMPM (HTM/ETM) Surface resistance [Ω/□] >10 ¹⁴ 10 ^9-10 10 ^9-10 10 ^11~12 10 ^11~12 Conductive layer mobility
[㎠V ^-1 s ^-1 ] - One 10 ^-2 10 ^-3 10 ^-4 Saturation voltage [kv] ~ -2.8 ~ -2.0 ~ -2.3 -2.3 ~ -2.5 -2.3 ~ -2.5 Half-life
[sec] Light on >300 5-10 10-15 20~30 25~35 Light off >300 50~60 70~85 100~110 30~40

Referring to Table 1, Comparative Example 1 had the largest surface resistance value, and the half-life was not measured. From Comparative Example 1, when the conductive layer is not included, it can be seen that the resistance of the substrate structure increases and the discharge characteristics are poor.

In the case of Comparative Example 2, Comparative Example 3, and Comparative Example 4, it can be seen that in the light on state, the half-life is low, but in the light off state, the half-life is long. In particular, the half-life in the light off state has a value of 3 times or more of the half-life in the light on state. In the light on state, energy in the form of light may be provided to the polyimide of the substrate. Accordingly, since the electric charge transfer due to the electron donor-acceptor interaction between the diamine unit and the diimide unit in the polyimide is actively performed, discharge characteristics are improved, and thus a low half-life value may appear. However, in the light off state, there is no energy for active electron donor-acceptor interaction, so it can be seen that the half-life increases compared to the light on state.

In the case of Example 1, compared with Comparative Examples 2 to 4, the surface resistance is relatively high and the mobility is low. However, Example 1 has a value of 50 seconds or less in both the light on and light off states, so it can be confirmed that the discharge characteristics are excellent. In particular, in Example 1, since the conductive layer is formed of a combination of a hole transport material (HTM) and an electron transport material (ETM), energy for actively moving residual charges on the substrate may be provided even in a light off state. In other words, in Example 1, energy in the form of light may be generated by combining holes and electrons in the conductive layer even in the light off state. Energy generated in the conductive layer is used for charge transfer of the substrate, thereby improving discharge characteristics of the display device.

In particular, since the substrate is generally disposed inside the case of the display device, it is difficult to provide energy in the form of a separate light for charge transfer of the substrate. Therefore, it is important that the display device has excellent discharge characteristics even in the light off state. As a result, Comparative Examples 2 to 4 show excellent discharge characteristics in the light-on state, but the discharge characteristics are not good in the light-off state. That is, it can be seen that the materials used in Comparative Examples 2 to 4 are not suitable as conductive layer materials because they show a large difference in discharge characteristics according to environmental changes. On the other hand, Example 1 has excellent discharge characteristics in both light on and light off states. In particular, the half-life in the light-off state of Example 1 has a level substantially equal to the half-life in the light-on state. Therefore, when the conductive layer is formed of a combination of a hole transport material (HTM) and an electron transport material (ETM), it can be seen that discharge characteristics are excellent.

Table 2 compares the properties of a conductive layer according to a combination of a hole transport material (HTM) and an electron transport material (ETM). In each example, the ratio of the hole transport material (HTM) and the electron transport material (ETM) was composed of 3:1. The results in Table 2 were measured in the same manner as in Table 1.

Example 1 Example 2 Example 3 Example 4 Conductive layer material (HTM / ETM) m-MTDATA / B3PYMPM m-MTDATA / TPBi NPB/B3PYMPM NPB/TPBi Surface resistance [Ω/□] 10 ^11~12 10 ^11~12 10 ^11~12 10 ^11~12 Mobility of conductive layer [㎠V ^-1 s ^-1 ] 10 ^-4 10 ^-4 10 ^-4 10 ^-4 HTM HOMO / LUMO [eV] -5.0 / -2.0 -5.0 / -2.0 -5.4 / -2.4 -5.4 / -2.4 ETM HOMO / LUMO [eV] -6.8 / -3.2 -6.2 / -3.0 -6.8 / -3.2 -6.2 / -3.0 Saturation voltage [kv] -2.3 ~ -2.5 -2.3 ~ -2.5 -2.3 ~ -2.5 -2.3 ~ -2.5 Half-life
[sec] Light on 25~35 40~55 50~60 50~65 Light off 30~40 55~70 60~70 45~60

Referring to Table 2, each of Examples 1 to 4 has an equal level of half-life in both the light on state and the light off state. In other words, since the conductive layer includes both a hole transport material (HTM) and an electron transport material (ETM), it can provide energy by the combination of holes and electrons to the substrate, so even in the light off state, discharge at the same level as the light on state. It can be confirmed once again that the characteristic can be expressed.

In particular, in the case of Examples 1 and 4, it can be seen that the half-life of about 50 seconds. Therefore, as a combination of a hole transport material (HTM) and an electron transport material (ETM), when m-MTDATA / B3PYMPM of Example 1 and NPB / TPBi of Example 4 are applied, the conductive layer material has better discharge characteristics. I can.

Table 3 compares the properties of the conductive layer according to the ratio of the hole transport material (HTM) and the electron transport material (ETM). At this time, m-MTDATA was used as the hole transport material (HTM), and B3PYMPM was used as the electron transport material (ETM). The results in Table 3 were measured in the same manner as in Table 1.

Example 1 Example 5 Comparative Example 5 Comparative Example 6 HTM/ETM ratio 3:1 2:1 1:1 1:2 Saturation voltage [kv] -2.3 ~ -2.5 -2.3 ~ -2.5 -2.3 ~ -2.5 -2.3 ~ -2.5 Half-life
[sec] Light on 25~35 30~45 55~70 90~100 Light off 30~40 30~40 60~70 100~120

In general, the mobility of the hole transport material (HTM) is greater than that of the electron transport material (ETM). For example, referring to Table 1 again, in the case of Comparative Example 4 in which the conductive layer is composed of only a hole transport material (HTM), Example 1 in which the conductive layer is composed of a hole transport material (HTM) and an electron transport material (ETM). Compared to, the mobility of the entire conductive layer is greater. In addition, in the light-on state, energy in the form of light may be provided to the polyimide of the substrate, so that even if the conductive layer is formed of the hole transport material (HTM) alone, charge discharge from the substrate may be easily performed. Specifically, in the light on state, charge can be easily discharged by the hole transport material (HTM) having a fast mobility. However, in Comparative Example 4, since the conductive layer is made of only a hole transport material (HTM) and energy in the form of light is not provided in the light off state, discharge characteristics are deteriorated, which is not preferable. That is, it may be preferable that the conductive layer is formed of a combination of a hole transport material (HTM) and an electron transport material (ETM) when both the light on state and the light off state are considered.

In addition, it may be advantageous in terms of mobility to configure the conductive layer so that the content of the hole transport material (HTM) is greater than the content of the electron transport material (ETM). When a conductive layer is formed by mixing two different materials, the mobility of the conductive layer may have a value similar to that of a material having a higher content. For example, the mobility of m-MTDATA, which is a hole transport material (HTM) used in the experimental results of Table 3, is 10 ^-4 ㎠V ^-1 s ^-1 , and the mobility of B3PYMPM, which is an electron transport material (ETM), is It is 10 ^-5 ㎠V ^-1 s ^-1 . In addition, referring to Example 1 of Table 1, it can be seen that ^{the mobility of the conductive layer is 10 -4} cm ^{2 V -1} s ^-1. That is, when the content of the hole transport material (HTM) having a relatively high mobility is larger than the content of the electron transport material (ETM), the conductive layer has a degree of mobility enough to sufficiently combine holes and electrons, and discharge characteristics. This can be improved.

Referring to Table 3, it can be seen that as the content of the hole transport material (HTM) is greater than the content of the electron transport material (ETM), the half-life decreases, so that the discharge characteristics are excellent. On the other hand, in the case of Comparative Example 6 in which the content of the electron transport material (ETM) is twice the content of the hole transport material (HTM), it can be seen that the half-life is significantly increased and the discharge characteristics are deteriorated. That is, as the content of the hole transport material (HTM) increases, the mobility of the conductive layer is improved, so that discharge characteristics may be improved. In particular, it can be seen from Table 3 that the content of the hole transport material (HTM) is preferably at least twice the content of the electron transport material (ETM). However, even if the content of the hole transport material HTM is greater than three times the content of the electron transport material ETM, the half-life may have a similar value. Specifically, when all of the electron transport material (ETM) for reacting with the hole transport material (HTM) is exhausted, formation of excitons may become impossible. Therefore, it may be preferable that the content of the hole transport material (HTM) is 2 or 3 times the content of the electron transport material (ETM).

A display device according to various embodiments of the present disclosure may be described as follows.

A display device according to an embodiment of the present invention includes a base film, a conductive layer on the base film, an adhesive layer on the conductive layer, a substrate on the adhesive layer, and a light emitting device on the substrate, and the conductive layer is a first conductive polymer material and a second conductive polymer. Contains substances.

According to another feature of the present invention, the content of the first conductive polymer material in the conductive layer may be at least twice the content of the second conductive polymer material.

According to another feature of the present invention, the mobility of the first conductive polymer material may be higher than that of the second conductive polymer material.

According to another feature of the present invention, the HOMO (Highest Occupied Molecular Orbital) and the Lowest Unoccupied Molecular Orbital (LUMO) of the first conductive polymer material may be larger than the HOMO and LUMO of the second conductive polymer material.

The first conductive polymer material may be a hole transport material, and the second conductive polymer material may be an electron transport material.

The first conductive polymer material may be m-MTDATA or NPB, and the second conductive polymer material may be B3PYMPM or TPBi.

The conductive layer may include a first conductive layer including a first conductive polymer material and a second conductive layer including a second conductive polymer material.

The conductive layer may be in an electrically floating state.

A display device according to an embodiment of the present invention includes a base film, a back film including a conductive layer and an adhesive layer, a substrate on the adhesive layer, a barrier layer on the substrate, and a light emitting device on the barrier layer, and the conductive layer is a hole transport material and an electron Contains transport materials.

According to another feature of the present invention, the conductive layer may be in an electrically floating state.

According to another feature of the present invention, the hole transport material may be m-MTDATA or NPB, and the electron transport material may be B3PYMPM or TPBi.

According to another feature of the present invention, the mobility of the hole transport material may be higher than that of the electron transport material.

According to another feature of the present invention, the content of the hole transport material in the conductive layer may be at least twice the content of the electron transport material.

According to another feature of the present invention, the HOMO and LUMO of the hole transport material may be larger than the HOMO and LUMO of the electron transport material.

According to another feature of the present invention, the conductive layer may include a first conductive layer including a hole transport material and a second conductive layer including an electron transport material.

Although the embodiments of the present invention have been described in more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made without departing from the spirit of the present invention. . Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but to explain the technical idea, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and are not restrictive. The scope of protection of the present invention should be construed by the following claims, and all technical ideas within the scope equivalent thereto should be construed as being included in the scope of the present invention.

100, 400: display device
110: back film
111: base film
112, 412: conductive layer
113: adhesive layer
120: substrate
121: barrier layer
122: gate insulating layer
123: interlayer insulating layer
124: passivation layer
125: overcoat layer
126: bank
130: transistor
131: active layer
132: gate electrode
133: source electrode
134: drain electrode
140: light emitting element
141: first electrode
142: light emitting layer
143: second electrode
150: bag
151: first encapsulation layer
152: foreign material cover layer
153: second encapsulation layer
412a: first conductive layer
412b: second conductive layer
50: substrate structure
51: base film
52: conductive layer
53: adhesive layer
54: substrate
55: barrier layer
AA: display area
NA: Non-display area
PX: Pixel
HTM: hole transport material
ETM: electron transport material

Claims (15)

Base film;
A conductive layer on the base film;
An adhesive layer on the conductive layer;
A substrate on the adhesive layer; And
Including a light emitting device on the substrate,
The display device, wherein the conductive layer includes a first conductive polymer material and a second conductive polymer material. The method of claim 1,
The display device, wherein the content of the first conductive polymer material in the conductive layer is at least twice the content of the second conductive polymer material. The method of claim 1,
The display device, wherein the mobility of the first conductive polymer material is higher than that of the second conductive polymer material. The method of claim 1,
The display device, wherein a Highest Occupied Molecular Orbital (HOMO) and a Lowest Unoccupied Molecular Orbital (LUMO) of the first conductive polymer material are larger than the HOMO and LUMO of the second conductive polymer material. The method of claim 1,
The first conductive polymer material is a hole transport material, and the second conductive polymer material is an electron transport material. The method of claim 5,
The first conductive polymer material is m-MTDATA or NPB,
The second conductive polymer material is B3PYMPM or TPBi. The method of claim 1,
The conductive layer includes a first conductive layer including the first conductive polymer material and a second conductive layer including the second conductive polymer material. The method of claim 1,
The display device, wherein the conductive layer is in an electrically floating state. A back film including a base film, a conductive layer, and an adhesive layer;
A substrate on the adhesive layer;
A barrier layer on the substrate; And
Including a light emitting device on the barrier layer,
The conductive layer includes a hole transport material and an electron transport material. The method of claim 9,
The display device, wherein the conductive layer is in an electrically floating state. The method of claim 9,
The hole transport material is m-MTDATA or NPB,
The electron transport material is B3PYMPM or TPBi. The method of claim 9,
The display device, wherein a mobility of the hole transport material is higher than a mobility of the electron transport material. The method of claim 9,
The display device, wherein the content of the hole transport material in the conductive layer is at least twice the content of the electron transport material. The method of claim 9,
The HOMO and LUMO of the hole transport material are larger than the HOMO and LUMO of the electron transport material. The method of claim 9,
The conductive layer includes a first conductive layer including the hole transport material and a second conductive layer including the electron transport material.

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