KR102650957B1 - Organic light emitting display device - Google Patents

Abstract

An organic light emitting display device according to an embodiment of the present invention includes a thin film transistor on a substrate, a planarization layer on the thin film transistor, a first electrode on the planarization layer and connected to the thin film transistor, and at least a portion of the first electrode. and a first bank layer on the planarization layer, a second bank layer on the first bank layer, a light emitting unit including an organic material layer and an organic light emitting layer on the first electrode, and a second electrode on the light emitting unit. The first bank layer and the second bank layer each include black pigment, the refractive index of the second bank layer is greater than that of the first bank layer, the thickness of the first bank layer is D, and the wavelength of light is 700 nm or more. When the integer excluding λ and negative is m, D=(2m+1)λ/4 is satisfied.

Description

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

The present invention relates to an organic light emitting display device, and more specifically, to an organic light emitting display device that can minimize reflection from external light and image quality defects caused by a light source for fingerprint recognition.

An organic light emitting display (OLED) is a self-emitting display device that injects holes and electrons into the light emitting layer from an anode for hole injection and a cathode for electron injection, respectively. It is a display device using an organic light emitting device that emits light when an exciton, which is a combination of injected holes and electrons, falls from the excited state to the ground state.

Organic light emitting display devices are divided into top emission, bottom emission, and dual emission types depending on the direction in which light is emitted. Depending on the driving method, organic light emitting display devices are classified as passive matrix type. It can be divided into Matrix and Active Matrix.

Unlike liquid crystal displays (LCDs), organic light emitting displays do not require a separate light source and can be manufactured in a lightweight and thin form. In addition, organic light emitting display devices are not only advantageous in terms of power consumption due to low voltage driving, but also have excellent color reproduction, response speed, viewing angle, and contrast ratio (CR), and are being studied as next-generation display devices.

An organic light emitting display device includes an organic light emitting device that includes a plurality of organic light emitting layers that emit different colors between two electrodes. For example, the organic light-emitting layer may be composed of a red light-emitting layer for emitting red light, a green light-emitting layer for emitting green light, and a blue light-emitting layer for emitting blue light, separated into red sub-pixels, green sub-pixels, and blue sub-pixels, respectively. You can. Each light emitting layer may be deposited in a pattern using a mask with openings for each sub-pixel, for example, a fine metal mask (FMM).

The organic light emitting display device includes a bank layer for defining each sub-pixel, and the bank layer of the organic light emitting display device may be made of a transparent material. As light transmitted from the outside through this transparent bank layer is reflected by the metal layer below the bank layer, a problem occurs in which reflection by external light of the organic light emitting display device increases.

Additionally, various functions in addition to the function of displaying images have recently been added to organic light emitting display devices, and as part of this, research is being actively conducted on organic light emitting display devices that can implement fingerprint recognition functions. Therefore, in order to apply the fingerprint recognition function to the organic light emitting display device, when a light source for fingerprint recognition is additionally placed at the bottom of the organic light emitting display device, the light emitted from the lower light source is not completely blocked by the bank layer and the user As this is noticed, a reddish defect, which is an image quality defect in which the entire screen of an organic light emitting display device appears red, may occur.

The inventor of the present invention recognized the above-mentioned problems and invented an organic light emitting display device that can reduce reflection by external light and minimize the occurrence of image quality defects caused by a light source for fingerprint recognition.

The problem to be solved according to embodiments of the present invention is to provide an organic light emitting display device that can reduce reflection by external light and minimize the occurrence of image quality defects caused by a light source for fingerprint recognition by improving the structure of the bank layer of the organic light emitting display device. The purpose is to provide

Problems to be solved according to embodiments of the present invention are not limited to the problems mentioned above, and other problems not mentioned will be clearly understood by those skilled in the art from the description below.

In order to solve the problems described above, an organic light emitting display device is provided that can reduce reflection by external light and minimize the occurrence of image quality defects caused by a light source for fingerprint recognition.

An organic light emitting display device according to an embodiment of the present invention includes a thin film transistor on a substrate, a planarization layer covering the thin film transistor, the planarization layer, a first electrode connected to the thin film transistor, and at least a portion of the first electrode, and a planarization layer. It includes a first bank layer on the first bank layer, a second bank layer on the first bank layer, a light-emitting portion including an organic material layer and an organic light-emitting layer on the first electrode, and a second electrode on the light-emitting portion, and the first The bank layer and the second bank layer each include black pigment, the refractive index of the second bank layer is greater than the refractive index of the first bank layer, the thickness of the first bank layer is D, and the wavelength of light of 700 nm or more is λ, negative. When the excluded integer is m, D=(2m+1)λ/4 is satisfied.

In another aspect, an organic light emitting display device including a thin film transistor and an organic light emitting layer between a first electrode and a second electrode includes a planarization layer on the thin film transistor, a material on the planarization layer, and a black pigment. It includes a first bank layer and a second bank layer on the first bank layer, wherein the refractive index of the first bank layer is greater than the refractive index of the planarization layer, and the refractive index of the second bank layer is greater than the refractive index of the first bank layer. is formed

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

The organic light emitting display device according to an embodiment of the present invention is configured to include at least two bank layers containing black pigment, thereby minimizing reflection by external light to reduce surface reflection luminance, thereby improving outdoor visibility of the organic light emitting display device. can be improved.

In addition, the organic light emitting display device according to an embodiment of the present invention is configured such that the refractive index of the first bank layer is greater than the refractive index of the planarization layer, the refractive index of the second bank layer is greater than the refractive index of the first bank layer, and the first bank layer Configured to satisfy this specific thickness, the light emitted from the fingerprint recognition light source and reflected from the lower portions of the first and second bank layers is extinguished by destructive interference, preventing the light from the light source from being recognized from the outside. can be minimized.

In addition, in the organic light emitting display device according to an embodiment of the present invention, the first bank layer and the second bank layer formed on the planarization layer block the light emitted from the light source for fingerprint recognition, thereby minimizing the occurrence of defects in which light is recognized from the outside. As a result, the image quality of the organic light emitting display device can be improved.

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

Since the content of the invention described in the problem to be solved, the means for solving the problem, and the effect described above do not specify the essential features of the claim, the scope of the claim is not limited by the matters described in the content of the invention.

1 is a diagram showing a cross-sectional structure of an organic light emitting display device according to an embodiment of the present invention.
FIG. 2 is a diagram showing a cross-sectional structure of a light emitting portion of an organic light emitting display device according to an embodiment of the present invention.
FIG. 3 is a diagram illustrating a method of measuring reflected luminance of an organic light emitting display device according to an embodiment of the present invention.
FIG. 4 is a diagram showing light transmittance for each wavelength band of the first bank layer of an organic light emitting display device according to an embodiment of the present invention.
FIG. 5 is a diagram showing a cross-sectional structure of area A of FIG. 1 of an organic light emitting display device according to an embodiment of the present invention.
Figure 6 is a diagram showing a cross-sectional structure of an organic light emitting display device according to another embodiment of the present invention.

The advantages and features of the present invention and methods for achieving them will become clear by referring to the embodiments described in detail below along with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and will be implemented in various different forms. The present embodiments only serve to ensure that the disclosure of the present invention is complete, and are known to those skilled in the art in the technical field to which the present invention pertains. It is provided to fully inform those who have 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 embodiments of the present invention are illustrative, and the present invention is not limited to the matters shown. Like reference numerals refer to like elements throughout the specification. Additionally, in describing the present invention, if it is determined that a detailed description of related known technologies may unnecessarily obscure the gist of the present invention, the detailed description will be omitted. When 'includes', 'has', 'consists of', 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 plural is included unless specifically stated otherwise.

When interpreting a component, it is interpreted to include the margin of error even if there is no separate explicit description. In the case of a description of a positional relationship, for example, if the positional relationship of two parts is described as 'on top', 'on the top', 'on the bottom', 'next to', etc., 'immediately' Alternatively, there may be one or more other parts placed between the two parts, unless 'directly' is used.

Additionally, first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are merely used to distinguish one component from another. Accordingly, the first component mentioned below may also be the second component within the technical spirit of the present invention.

Each feature of the various embodiments of the present invention can be combined or combined with each other, partially or entirely, and various technological interconnections and operations are possible, and each embodiment can be implemented independently of each other or together in a related relationship. It may be possible.

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

1 is a diagram showing a cross-sectional structure of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 1, an organic light emitting display device 100 according to an embodiment of the present invention includes a substrate 110, a thin film transistor 120 located on the substrate 110, and a first electrode 140. and a light emitting portion 150 located between the second electrode 160 and including a plurality of organic material layers and an organic light emitting layer (EML).

The organic light emitting display device 100 includes a plurality of sub pixels. A sub-pixel refers to the smallest unit area where light is actually emitted. In addition, a plurality of sub-pixels may be gathered together to form a minimum group capable of expressing white light. For example, three sub-pixels constitute one group, and one red sub-pixel, one green sub-pixel, and one blue sub-pixel A group of can be formed. Alternatively, the four sub-pixels may form one group, and the red sub-pixel, green sub-pixel, blue sub-pixel, and white sub-pixel may form one group. However, it is not limited to this, and various sub-pixel designs are possible. In FIG. 1 , for convenience of explanation, only one sub-pixel among a plurality of sub-pixels of the organic light emitting display device 100 is shown.

In the organic light emitting display device 100 according to an embodiment of the present invention, the substrate 110 is formed of an insulating material to support various components of the organic light emitting display device 100. For example, the substrate 110 may be made of not only glass, but also a plastic substrate such as PET (PolyEthylene Terephthalate), PEN (PolyEthylene Naphthalate), or polyimide. When the organic light emitting display device is a flexible organic light emitting display device, the substrate 110 may be made of a flexible material such as plastic. In addition, when applying flexible organic light-emitting devices to automotive lighting devices or automotive displays, various designs of automotive lighting devices can be designed according to the structure or exterior shape of the vehicle, and the degree of freedom in design is increased. can be secured.

A buffer layer 131 may be formed on the substrate 110 to block penetration of impure elements from the substrate 110 and the outside and to protect various components of the organic light emitting display device 100. The buffer layer 131 may be formed, for example, in a single-layer or multi-layer structure of a silicon oxide film (SiOx) or a silicon nitride film (SiNx), but is not limited thereto. The buffer layer 131 may be omitted depending on the structure or characteristics of the organic light emitting display device 100.

A thin film transistor 120 including a semiconductor layer 122, a gate electrode 121, a source electrode 123, and a drain electrode 124 is formed on the buffer layer 131.

Specifically, a semiconductor layer 122 is formed on the substrate 110, and a gate insulating layer 132 is formed on the semiconductor layer 122 to insulate the semiconductor layer 122 and the gate electrode 121. An interlayer insulating layer 133 is formed on the gate electrode 121 to insulate the gate electrode 121, the source electrode 123, and the drain electrode 124. A source electrode 123 and a drain electrode 124 respectively contacting the semiconductor layer 122 are formed on the interlayer insulating layer 133. The source electrode 123 or the drain electrode 124 is electrically connected to the semiconductor layer 122 through a contact hole.

The semiconductor layer 122 may be formed of amorphous silicon (a-Si), polycrystalline silicon (poly-Si), an oxide semiconductor, or an organic semiconductor. When the semiconductor layer 122 is made of an oxide semiconductor, it may be made of any one of IGZO (Indium Gallium Zinc Oxide), ZTO (Zinc Tin Oxide), IZO (Indium Zinc Oxide), or ITZO (Indium Tin Zinc Oxide). , but is not limited to this.

The gate insulating layer 132 may be formed as a single-layer or multi-layer structure made of an inorganic insulating material such as silicon oxide (SiOx), silicon nitride (SiNx), etc., but is not limited thereto.

The gate electrode 121 functions to transmit a gate signal to the thin film transistor 120, and is comprised of at least one metal selected from aluminum (Al), molybdenum (Mo), titanium (Ti), and copper (Cu) or an alloy thereof. It may be formed of a single-layer or multi-layer structure made of the above metal or an alloy thereof, but is not limited thereto.

The source electrode 123 and the drain electrode 124 serve to transmit an external electrical signal from the thin film transistor 120 to the light emitting unit 150. The source electrode 123 and the drain electrode 124 may be made of at least one metal selected from aluminum (Al), molybdenum (Mo), titanium (Ti), and copper (Cu), or an alloy thereof, and may be made of the metal or alloy thereof. It may be formed as a single-layer or multi-layer structure made of alloy, but is not limited thereto.

In this specification, for convenience of explanation, only the driving thin film transistor 120 connected to the first electrode 140 is shown among various thin film transistors that may be included in the organic light emitting display device 100. Each sub-pixel may further include a switching thin film transistor or capacitor.

A protective layer 170 is formed on the thin film transistor 120. The protective layer 170 may be made of an inorganic insulating material. For example, the protective layer 170 may be made of a silicon oxide film (SiOx) or a silicon nitride film (SiNx), but is not limited thereto. The protective layer 170 may be omitted depending on the structure or characteristics of the organic light emitting display device 100.

A planarization layer 134 is formed on the protective layer 170. The planarization layer 134 functions to planarize components such as the thin film transistor 120 on the substrate 110. The planarization layer 134 may be composed of a single layer or multiple layers, and may be made of an organic material. For example, the planarization layer 134 may be made of polyimide, photo acryl, or benzocyclobutene (BCB), but is not limited thereto.

The protective layer 170 and the planarization layer 134 include a contact hole 135 for electrically connecting the thin film transistor 120 and the first electrode 140 in each sub-pixel.

The first electrode 140 is formed on the planarization layer 134. The first electrode 140 may be an anode and is made of a conductive material with a relatively high work function value and serves to supply holes to the organic light-emitting layer of the light-emitting portion 150. The first electrode 140 is electrically connected to the thin film transistor 120 through the contact hole 135 provided in the protective layer 170 and the planarization layer 134, and is, for example, the source of the thin film transistor 120. It may be electrically connected to the electrode 123. Additionally, the first electrode 140 is arranged to be spaced apart for each sub-pixel. The first electrode 140 is formed of a transparent conductive material, for example, indium tin oxide (ITO), indium zinc oxide (IZO), etc., but is limited thereto. It doesn't work.

In addition, when the organic light emitting display device 100 according to an embodiment of the present invention is a top emission type, the light emitted from the organic light emitting layer of the light emitting unit 150 is reflected to the first electrode 140, thereby enabling smoother operation. A reflective layer made of a metal material with excellent reflection efficiency, for example, aluminum (Al) or silver (Ag), is additionally formed on the top or bottom of the first electrode 140 so that it can be emitted in the upward direction. It can be.

For example, the first electrode 140 may have a two-layer structure in which a transparent conductive layer made of a transparent conductive material and a reflective layer are sequentially stacked, or it may have a three-layer structure in which a transparent conductive layer, a reflective layer, and a transparent conductive layer are sequentially stacked. The reflective layer may be silver (Ag) or an alloy containing silver, for example, silver (Ag) or APC (Ag/Pd/Cu).

In describing the organic light emitting display device 100 according to an embodiment of the present invention, the top emission method is such that light emitted from the organic light emitting layer of the light emitting unit 150 is emitted in the direction of the second electrode 160. The bottom emission method refers to a method in which light is emitted in the direction of the first electrode 140, which is opposite to the top emission method.

Referring to FIG. 1, the organic light emitting display device 100 according to an embodiment of the present invention covers at least a portion of the first electrode 140 and includes a first bank layer 141 formed on the planarization layer 134 and It is configured to include a second bank layer 142 formed on the first bank layer 141.

Additionally, the first bank layer 141 and the second bank layer 142 of the organic light emitting display device 100 according to an embodiment of the present invention are each configured to include black pigment.

In the case of a conventional organic light emitting display device, the bank layer is formed of a transparent material, so light incident from the outside is transmitted through the transparent bank layer, and the first electrode 140 is located below the bank layer and includes a layer made of a metal material. It is reflected from the back. Accordingly, the organic light emitting display device 100 has a problem in that reflection due to external light occurs. Additionally, when applying the organic light emitting display device 100 to a vehicle display device, it becomes difficult to apply the organic light emitting display device 100 to a vehicle display device due to reflection by external light. Accordingly, in order to minimize reflection by external light of the organic light emitting display device, the first bank layer 141 and the second bank layer 142 of the organic light emitting display device 100 according to an embodiment of the present invention reflect external light. It must be composed of materials that minimize

In addition, the first bank layer 141 and the second bank layer 142 are designed so that the light emitted from the fingerprint recognition light source 180 located at the bottom of the substrate 110 is not recognized by the user to implement the fingerprint recognition function. It must be possible to minimize the transmission of light emitted from the bottom of (110).

Referring to FIG. 1, the first bank layer 141 and the second bank layer 142 of the organic light emitting display device 100 according to an embodiment of the present invention are each made of a material containing black pigment. It can be configured. That is, the photo resist for forming the first bank layer 141 and the second bank layer 142 may be made of a material containing black pigment. Black pigment may be composed of organic or inorganic materials.

Black pigment may be composed of carbon-based or metal oxide. Additionally, the photoresist may contain photosensitive compounds including at least one of a polymer, a monomer, and a photoinitiator. Additionally, the photoresist may contain a solvent that disperses the photosensitive compound.

Looking at the reaction mechanism, the photoresist before exposure has black pigment dispersed in a photosensitive compound by a solvent. The solvent in the photoresist can be removed in a vacuum drying process or a curing process. And, after exposure, the photoinitiator contained in the photosensitive compound generates radicals by light. In addition, the monomer included in the photoresist has a double bond, so it reacts with the radical of the photoinitiator and causes cross-linking. Accordingly, after exposure, a photoresist with a high molecular weight is formed and thus is not dissolved by a developer. Afterwards, in the developing process using a developer, the portions not dissolved by the developer become the first bank layer 141 and the second bank layer 142, and the portions dissolved by the developer are removed. Accordingly, the photoresist forming the first bank layer 141 and the second bank layer 142 can be said to be a negative photoresist.

Additionally, in order to improve crosslinking after exposure, the photoinitiator included in the photoresist may include an imine-based photoinitiator. For example, the imine-based photoinitiator may include at least one of an oxime and an oxime ester. Oximes or oxime esters are long-wavelength photoinitiators that can improve crosslinking. Here, long wavelength refers to 365nm or more. Additionally, the light source used during exposure is a high-pressure mercury lamp and has multiple wavelengths. The multiple wavelengths may be 436 nm for the G-line, 405 nm for the H-line, and 365 nm for the I-line. Among these, the photoetching process is performed using the I-line of 365nm or higher.

In addition, oxime or oxime ester can minimize by-products generated after exposure, and thus can minimize impurities generated when the by-products react with other molecules in the baking process, which is a subsequent process after cross-linking. In addition, since oxime or oxime ester is used together with black pigment, it is possible to form the first bank layer 141 and the second bank layer 142 with high light blocking properties. Alternatively, the photoinitiator may be composed of an oxime or oxime ester and acetophenone.

For example, oxime can be represented by Formula 1 below.

[Formula 1]

Here, R and R' may be either an alkyl group or a phenyl group having 1 to 15 carbon atoms.

For example, oxime ester can be represented by Formula 2 below.

[Formula 2]

Here, R is an aryl group, and R' may be either an alkyl group having 1 to 15 carbon atoms or a phenyl group.

The monomer may contain a hexafunctional group, for example, DPHA (DiPentaerythritol HexaAcrylate). This DPHA has double bonds and can be quickly cured by light after crosslinking. Accordingly, the photoresist for forming the first bank layer 141 and the second bank layer 142 can be formed as a hard film, and the development resistance is improved so that the film is not lost even during the development process with a high concentration of developer. There is an effect.

Additionally, the polymer of the photoresist includes a cardo-based polymer. Cardo-based polymers have excellent heat resistance, miscibility with pigments, and solubility. Additionally, the polymer of the photoresist may further include epoxy acrylate. Therefore, the polymer of the photoresist containing cardo-based or epoxy acrylate serves to improve dispersibility by allowing the black pigment to be well dispersed within the polymer. Dispersibility refers to the uniformity of the photoresist, and as dispersibility improves, the more uniform first bank layer 141 and second bank layer 142 can be formed.

For example, the cardo series polymer can be expressed as [Chemical Formula 3] below.

[Formula 3]

And, the developer may be, for example, TetraMethylAmmoniumHydroxide (TMAH) or Potassium Hydroxide (KOH).

Additionally, since the first bank layer 141 and the second bank layer 142 contain black pigment, optical density (OD), which indicates the degree of light blocking, increases. As optical density increases, reflection by external light can be minimized. However, if the optical density becomes too high, the dielectric constant may increase and leakage current may occur in adjacent sub-pixels. Therefore, taking this into account, the optical densities of the first bank layer 141 and the second bank layer 142 ( It is preferable that the optical density is 4 or less.

In addition, since the first bank layer 141 and the second bank layer 142 are made of a material containing black pigment, when the incident angle of incident light is 45 degrees, the reflection luminance at a reflection angle of 30 degrees can be configured to be 30 nit or less. there is. Accordingly, reflection by external light can be improved and reflected luminance can be reduced. The reflected luminance of the first bank layer 141 and the second bank layer 142 is measured with DMS803. Here, the reflected luminance may include reflected luminance on the left and right sides of the organic light emitting display device. That is, the left and right reflected luminance may be 30 nit or less at a reflection angle of 30 degrees when the incident angle of incident light is 45 degrees. Additionally, when an organic light emitting display device is applied to a vehicle display device, a display device with minimal reflection by external light can be provided. Additionally, since reflection by external light of the organic light emitting display device can be minimized, viewing characteristics of the organic light emitting display device in the left and right directions can be improved.

Additionally, the first bank layer 141 and the second bank layer 142 of the organic light emitting display device 100 according to an embodiment of the present invention are formed to have different refractive indices. Additionally, the refractive index of the first bank layer 141 and the second bank layer 142 is formed to be different from the refractive index of the planarization layer 134.

More specifically, the refractive index of the first bank layer 141 may be greater than the refractive index of the planarization layer 134 located below the first bank layer 141. For example, when a material with a refractive index of 1.49 is used as the planarization layer 134, a material with a refractive index of 1.55 may be used as the first bank layer 141. For example, the first bank layer 141 may be made of one of polyimide, photo acryl, and benzocyclobutene (BCB).

Additionally, the refractive index of the second bank layer 142 may be greater than the refractive index of the first bank layer 141 located below the second bank layer 142. For example, if a material with a refractive index of 1.55 is used as the first bank layer 141, a material with a refractive index of 1.60 may be used as the second bank layer 142. For example, the second bank layer 142, which has a greater refractive index than the first bank layer 141, may include 4,4-thiodibenzenethiol (TDT)-based epoxy acrylate.

That is, in the organic light emitting display device 100 according to an embodiment of the present invention, the refractive index of the first bank layer 141 is greater than the refractive index of the planarization layer 134, and the refractive index of the second bank layer 142 is greater than the refractive index of the first bank layer 142. It may be set to be greater than the refractive index of the layer 141.

Light emitted from the fingerprint recognition light source 180 disposed at the bottom of the substrate 110 passes through the planarization layer 134, the first bank layer 141, and the second bank layer 142, each of which has a different refractive index. A portion of the light may be reflected back toward the fingerprint recognition light source 180 and blocked by the first bank layer 141 and the second bank layer 142.

That is, the light emitted from the fingerprint recognition light source 180 disposed at the bottom of the substrate 110 is partially reflected at the boundary between the planarization layer 134 and the first bank layer 141, which have different refractive indices, and is reflected in the first bank layer 141. The light that has passed through the bank layer 141 may be partially reflected at the boundary between the first bank layer 141 and the second bank layer 142 whose refractive indices are set differently.

In addition, the thickness of the first bank layer 141 of the organic light emitting display device 100 according to an embodiment of the present invention is D, and the light source 180 for fingerprint recognition has a wavelength of 700 nm or more. ) can be set to satisfy the relationship of D=(2m+1)λ/4 when the wavelength is λ and the integer excluding sound is m.

Therefore, when the thickness of the first bank layer 141 of the organic light emitting display device 100 according to an embodiment of the present invention is set to satisfy the relationship of D = (2m + 1) λ / 4, the planarization layer 134 ) and the phase of the light reflected at the boundary of the first bank layer 141 and the phase of the light reflected at the boundary between the first bank layer 141 and the second bank layer 142 are different by 180 degrees, and the light has an opposite phase. As the wavelengths overlap, destructive interference may occur, causing the reflected light to disappear. That is, the light emitted from the fingerprint recognition light source 180 and reflected from the lower portions of each of the first bank layer 141 and the second bank layer 142 is extinguished by destructive interference. Therefore, it is possible to minimize defects that are perceived externally by the light emitted from the fingerprint recognition light source 180.

Additionally, referring to FIG. 1, so that the second bank layer 142 can be stably formed on the first bank layer 141 having a multi-layer structure, the width of the lower end of the second bank layer 142 is equal to the width of the first bank layer 142. It may be formed to be smaller than the width of the upper end of the bank layer 141.

Additionally, the dielectric constant of the first bank layer 141 of the organic light emitting display device 100 according to an embodiment of the present invention must be set in consideration of leakage current to adjacent sub-pixels. As the organic layers constituting the light emitting unit 150 are composed of a common layer to correspond to a plurality of sub-pixels, the leakage current is caused by the common organic material layer such as a hole injection layer or a hole transport layer when applying a current to drive a specific sub-pixel. This is a phenomenon in which current flows to other neighboring sub-pixels. This leakage current causes other sub-pixels to unintentionally emit light, causing color mixing between sub-pixels and lowering luminance. Therefore, the first bank layer 141 on the planarization layer 134 of the organic light emitting display device 100 according to an embodiment of the present invention must be made of a material with a low dielectric constant, specifically 7 C/m ² (Coulomb/m ² ) It may be composed of a material with a dielectric constant below.

A light emitting unit 150 is formed on the first electrode 140, the first bank layer 141, and the second bank layer 142. The light emitting unit 150 may include various organic layers as needed, and essentially includes an organic light emitting layer (EML). Additionally, depending on the structure of the organic light emitting display device, it may include a plurality of organic light emitting layers. The organic material layer may include at least one hole transport layer (HTL) and an electron transport layer (ETL), a hole injection layer (HIL), an electron injection layer (EIL), a hole blocking layer (HBL), and an electron blocking layer (EBL). ) may further include functional layers such as the like. Additionally, the plurality of organic material layers included in the light emitting unit 150 may have a common layer structure to correspond to all of the red sub-pixel (R), green sub-pixel (G), and blue sub-pixel (B).

A second electrode 160 is formed on the light emitting unit 150. The second electrode 160 may be a cathode, and is made of a conductive material with a low work function because it must supply electrons to the organic light-emitting layer of the light-emitting part. More specifically, the second electrode 160 may be made of a metal material such as magnesium (Mg), silver-magnesium (Ag:Mg), but is not limited thereto.

In addition, when the organic light emitting display device 100 according to an embodiment of the present invention is a top emission type, the second electrode 160 is made of indium tin oxide (ITO) or indium zinc oxide (IZO). ), Indium Tin Zinc Oxide (ITZO), Zinc Oxide (ZnO), and Tin Oxide (TiO) series of transparent conductive oxides, but is not limited thereto.

The organic light emitting display device 100 according to an embodiment of the present invention may be configured to include a light source 180 for fingerprint recognition located below the substrate 110. The light source 180 may be additionally configured to the organic light emitting display device to implement an optical fingerprint recognition function, and the light irradiated from the fingerprint recognition light source 180 to the substrate 110 is reflected by the user's finger. , the reflected light is sensed by a photo sensor made of a thin film transistor on the substrate 110 to recognize the fingerprint.

The light source 180 for fingerprint recognition may be a light source with a short wavelength of 300 nm to 700 nm or a light source with a long wavelength of 700 nm or more, depending on the structure of the organic light emitting display device.

FIG. 2 is a diagram showing a cross-sectional structure of a light emitting portion of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 2 , the light emitting unit 150 of the organic light emitting display device 100 according to an embodiment of the present invention will be described in more detail.

Referring to FIG. 2, the light emitting unit 150 of the organic light emitting display device 100 according to an embodiment of the present invention includes a hole injection layer (HIL) 151 disposed on the first electrode 140, A first hole transport layer (152a, 1 ^st Hole Transport Layer: 1 ^st HTL) disposed on the hole injection layer 151, a second hole transport layer (152b, 2 ^nd Hole Transport) disposed on the first hole transport layer (152a) Layer: 2 ^nd HTL) and a third hole transport layer (152c, 3 ^rd Hole Transport Layer: 3 ^rd HTL), a red light-emitting layer (153a), a green light-emitting layer (153b) disposed on the hole transport layers (152a, 152b, 152c), and It includes an organic light emitting layer (EML) including a blue light emitting layer (153c) and an electron transport layer (ETL) (154) disposed on the organic light emitting layer.

The first electrode 140 is disposed on the planarization layer 134 to correspond to each of the red sub-pixel area (R), green sub-pixel area (G), and blue sub-pixel area (B) defined on the substrate.

The hole injection layer 151 is disposed on the first electrode 140 as a common layer to correspond to all of the red sub-pixel area (R), green sub-pixel area (G), and blue sub-pixel area (B).

The hole injection layer 151 may play a role in facilitating hole injection, and may contain HATCN (1,4,5,8,9,11-hexaazatriphenylene-hexanitrile), CuPc (cupper phthalocyanine), and PEDOT (poly(3) ,4)-ethylenedioxythiophene), PANI (polyaniline) and NPD(N,N-dinaphthyl-N,N'-diphenylbenzidine), TPD(N,N'-Bis(3-methylphenyl)-N,N′'-bis( phenyl)-benzidine), α-NPB(Bis[N-(1-naphthyl)-N-phenyl]benzidine), TDAPB(1,3,5-tris(4-diphenylaminophenyl)benzene), TCTA(Tris(4- carbazoyl-9-yl)triphenylamine), spiro-TAD (2,2',7,7''-Tetrakis(N,N-diphenylamino)-9,9-spirobifluorene) and CBP (4,4'-bis(carbazol) -9-yl)biphenyl), but is not limited thereto.

The hole injection layer 151 may be formed by doping the material constituting the first hole transport layer 152a with a p-dopant. In this case, the hole injection layer 151 and the second hole transport layer 152a can be formed in a continuous process using one process equipment. The p-type dopant may be made of F ₄ -TCNQ (2,3,5,6-tetrafluoro-7,7,8,8-tetracyano-quinidimethane), but is not limited thereto.

The first hole transport layer 152a is disposed on the hole injection layer 151 as a common layer to correspond to all of the red sub-pixel area (R), green sub-pixel area (G), and blue sub-pixel area (B). The first hole transport layer 152a serves to facilitate the transport of holes, and contains NPD (N,N-dinaphthyl-N,N'-diphenylbenzidine), TPD (N,N'-bis-(3-methylphenyl)- N,N'-bis-(phenyl)-benzidine), spiro-TAD (2,2',7,7′'-Tetrakis(N,N-diphenylamino)-9,9-spirobifluorene) and MTDATA (4,4 It may be composed of one or more of ',4"-Tris(N-3-methylphenyl-N-phenyl-amino)-triphenylamine), but is not limited thereto.

The second hole transport layer 152b is disposed on the first hole transport layer 152a in the red sub-pixel region (R). Additionally, the third hole transport layer 152c is disposed on the first hole transport layer 152a in the green sub-pixel area (G).

The second hole transport layer 152b and the third hole transport layer 152c serve to smoothly transfer holes from the hole injection layer 151 to the red light-emitting layer 153a and the green light-emitting layer 153b, respectively.

Additionally, the thickness of each of the second hole transport layer 152b and the third hole transport layer 152c may form the optical distance of the micro cavity. More specifically, the thickness of each of the second hole transport layer 152b and the third hole transport layer 152c is such that the red light emitting layer 153a forms a micro cavity structure between the first electrode 140 and the second electrode 160. , and the green light emitting layer 153b may be determined to form a micro cavity structure between the first electrode 140 and the second electrode 160, and the micro cavity structure may be formed in the red sub-pixel area (R) and the green sub-pixel area (G). By forming the optical distance of the cavity, the efficiency of the organic light emitting display device 100 can be improved.

The red light emitting layer 153a is disposed on the second hole transport layer 152b in the red sub-pixel region (R). The red light-emitting layer 153a may include a light-emitting material that emits red light, and the light-emitting material may be formed using a phosphorescent material or a fluorescent material.

More specifically, the red light-emitting layer 153a may include a host material including CBP (carbazole biphenyl) or mCP (1,3-bis(carbazol-9-yl)benzene), Ir(btp) ₂ (acac) (bis(2-benzo[b]thiophen-2-yl-pyridine)(acetylacetonate)iridium(III)), Ir(piq) ₂ (acac)(bis(1-phenylisoquinoline)(acetylacetonate)iridium(III)), Ir(piq) ₃ may be made of a phosphorescent material containing a dopant including any one or more of (tris(1-phenylquinoline)iridium(III)) and PtOEP (octaethylporphyrin platinum), and in contrast, PBD:Eu(DBM)3 It may be made of a fluorescent material containing (Phen) or Perylene, but is not limited thereto.

The green light emitting layer 153b is disposed on the third hole transport layer 152c in the green sub-pixel area (G). The green light-emitting layer 153b may include a light-emitting material that emits green light, and the light-emitting material may be formed using a phosphorescent material or a fluorescent material.

More specifically, the green light emitting layer 153b may include a host material including CBP or mCP, Ir(ppy) ₃ (tris(2-phenylpyridine)iridium(III)) or Ir(ppy) ₂ (acaa)( It may be made of a phosphorescent material containing a dopant material such as an iridium complex (Ir complex) containing bis(2-phenylpyridine)(acetylacetonate)iridium(III), and in contrast, Alq ₃ (tris(8-hydroxyquinolino)aluminum). It may be made of a fluorescent material, but is not limited thereto.

The blue light emitting layer 153c is disposed on the first hole transport layer 152a in the blue sub-pixel area (Bp). The blue light-emitting layer 153c may include a light-emitting material that emits blue light, and the light-emitting material may be formed using a phosphorescent material or a fluorescent material.

More specifically, the blue light-emitting layer 153c may include a host material including CBP or mCP, and FIrPic (bis(3,5,-difluoro-2-(2-pyridyl)phenyl-(2-carboxypyridyl)iridium( III) It may be made of a phosphorescent material containing a dopant material including DPVBi(4,4'-bis[4-di-p-tolylamino)stryl)biphenyl), DSA(1-4-di- It may be made of a fluorescent material containing any one of [4-(N,N-di-phenyl)amino]styryl-benzene), PFO (polyfluorene)-based polymer, and PPV (polyphenylenevinylene)-based polymer, but is not limited thereto.

The electron transport layer 154 includes a red light-emitting layer 153a, a green light-emitting layer 153b, and a blue light-emitting layer 153c to correspond to all of the red sub-pixel region (R), green sub-pixel region (G), and blue sub-pixel region (B). placed on the table.

The electron transport layer 154 may play a role in transporting and injecting electrons, and the thickness of the electron transport layer 154 can be adjusted in consideration of electron transport characteristics.

The electron transport layer 154 serves to facilitate the transport of electrons, and includes Liq (8-hydroxyquinolinolato-lithium), Alq ₃ (tris(8-hydroxyquinolinato)aluminum), and PBD (2-(4-biphenylyl)-5- (4-tert-butylpheny)-1,3,4oxadiazole), TAZ(3-(4-biphenyl)4-phenyl-5-tert-butylphenyl-1,2,4-triazole), spiro-PBD and BAlq(bis It may be composed of one or more of (2-methyl-8-quinolinolate)-4-(phenylphenolato)aluminum), but is not limited thereto.

It is also possible to additionally configure an electron injection layer (EIL) on the electron transport layer 154.

The electron injection layer (EIL) may be made of a metal inorganic compound such as BaF ₂ , LiF, NaCl, CsF, Li ₂ O, and BaO, but is not limited thereto.

Here, the structure is not limited according to the embodiment of the present invention, and includes a hole injection layer 151, a first hole transport layer 152a, a second hole transport layer 152b, a third hole transport layer 153c, and an electron transport layer. At least one of (154) may be omitted. In addition, one of the hole injection layer 151, the first hole transport layer 152a, the second hole transport layer 152b, the third hole transport layer 153c, and the electron transport layer 154 may be formed as two or more layers. possible.

The second electrode 160 is disposed on the electron transport layer 154 to correspond to all of the red sub-pixel area (R), green sub-pixel area (G), and blue sub-pixel area (B).

A capping layer may be disposed on the second electrode 160. The capping layer is intended to improve the light extraction effect of the organic light emitting display device, and is the host of the first hole transport layer 152a, the electron transport layer 154, the red light emitting layer 153a, the green light emitting layer 153b, and the blue light emitting layer 153c. It may be made of any one of the substances. Additionally, the capping layer can be omitted depending on the structure or characteristics of the organic light emitting display device 100.

The organic light emitting layer 153 of the organic light emitting display device 100 according to an embodiment of the present invention may include at least one phosphorescent material. More specifically, the organic light-emitting layer 153 includes a red light-emitting layer 153a for emitting red light located in the red sub-pixel (R), and a green light-emitting layer (153a) for emitting green light located in the green sub-pixel (G). 153b), and may be configured to include a blue light emitting layer 153c for emitting blue light located in the blue sub-pixel (B). Here, the red light-emitting layer 153a contains a phosphorescent material, the green light-emitting layer 153b and the blue light-emitting layer 153c contain a fluorescent material, or the red light-emitting layer 153a and the green light-emitting layer 153b contain a phosphorescent material, and the blue light-emitting layer 153c ) may contain a fluorescent material, or the red light-emitting layer 153a, the green light-emitting layer 153b, and the blue light-emitting layer 153c may all contain a phosphorescent material.

In addition, the organic light emitting display device 100 according to an embodiment of the present invention is suitable for use in TVs, mobile devices, tablet PCs, monitors, laptop computers, vehicle displays, and vehicle displays. It can be applied to display devices, including lighting devices, etc. Alternatively, it may be applied to wearable display devices, foldable display devices, bendable display devices, and rollable display devices.

FIG. 3 is a diagram illustrating a method of measuring reflected luminance of an organic light emitting display device according to an embodiment of the present invention.

Referring to FIG. 3, when light of 400 nits is incident on the organic light emitting display device 100 at 45 degrees (the incident light is indicated as “X” in FIG. 3), the reflected luminance is at a reflection angle of 30 degrees among several reflected lights (Y). It refers to the luminance of reflected light. This reflected luminance is measured with the DMS803 equipment. Taking the reflection luminance of the organic light emitting display device 100 of FIG. 1 measured using this equipment as an example, the reflection luminance becomes 400 nits or more at an incident angle of 45 degrees and becomes more than 300 nits at a reflection angle of 30 degrees. When the reflected luminance is 300 nit or more, a problem occurs in which the left and right viewing characteristics of the organic light emitting display device 100 are deteriorated due to reflection by external light. Therefore, in order to minimize reflection by external light of the organic light emitting display device 100, the bank layer must be made of a material that does not reflect light transmitted from the outside. Accordingly, the inventor of the present specification conducted several experiments to improve the material of the bank layer.

Through various experiments, the inventor of the present specification has developed a material in which the bank layer includes a first bank layer and a second bank layer, and the first bank layer and the second bank layer each contain black pigment to minimize reflection of external light. It was composed.

That is, as described with reference to FIG. 1, in the case of the organic light emitting display device 100 according to an embodiment of the present invention, the first bank layer 141 on the planarization layer 134 formed to cover the thin film transistor and The second bank layers 142 on the first bank layer 141 are each made of a material containing black pigment, so that when the incident angle of light incident on the organic light emitting display device 100 is 45 degrees, the reflection angle is 30 degrees. The reflected luminance in degrees can be configured to be 30 nit or less. Therefore, the organic light emitting display device 100 according to an embodiment of the present invention can improve outdoor visibility of the organic light emitting display device by minimizing reflection by external light and reducing surface reflection luminance compared to existing structures.

FIG. 4 is a diagram showing light transmittance for each wavelength band of the first bank layer of an organic light emitting display device according to an embodiment of the present invention.

Looking at the light transmittance evaluation results for each wavelength band of the first bank layer 141 of the organic light emitting display device 100 according to an embodiment of the present invention with reference to FIG. 4, in the wavelength range of 300 nm to 700 nm, the first bank layer 141 ), the light was absorbed and no light transmission occurred. However, in the wavelength range of 700 nm or more, the light transmittance level of the first bank layer 141 rapidly increased.

That is, when applying only the first bank layer 141 to an organic light emitting display device, when applying a light source for fingerprint recognition to the lower part of the substrate, the first bank layer for a light source having a wavelength in the short wavelength region, that is, 300 nm to 700 nm. The blocking power of (141) is high, but the blocking power of the first bank layer 141 against a light source with a long wavelength region, that is, a wavelength of 700 nm or more, is low, so that the light emitted from the light source for fingerprint recognition at the bottom of the substrate is completely blocked by the bank layer. If the screen is not blocked properly and is recognized by the user, a reddish defect, which is an image quality defect in which the entire panel of the organic light emitting display device appears red, may occur.

FIG. 5 is a diagram showing a cross-sectional structure of area A of FIG. 1 of an organic light emitting display device according to an embodiment of the present invention.

That is, FIG. 5 is a diagram for explaining light absorption, reflection, and destructive interference conditions in the first and second bank layers of the organic light emitting display device 100 according to an embodiment of the present invention.

Referring to FIG. 5, the organic light emitting display device 100 according to an embodiment of the present invention has a first bank layer 141 on top of the planarization layer 134 that has a different refractive index from the planarization layer 134 and a different refractive index. ) and a second bank layer 142.

Referring to FIG. 5 , as described with reference to FIG. 4 , in the case of light having a short wavelength region, that is, a wavelength of 300 nm to 700 nm, emitted from the fingerprint recognition light source 180, the first bank layer 141 It can be blocked as it is absorbed.

Additionally, referring to FIG. 5 , the first bank layer 141 and the second bank layer 142 of the organic light emitting display device 100 according to an embodiment of the present invention are formed to have different refractive indices. Additionally, the refractive index of the first bank layer 141 and the second bank layer 142 is formed to be different from the refractive index of the planarization layer 134. That is, the refractive index (n ₁ ) of the planarization layer 134, the refractive index (n ₂ ) of the first bank layer 141, and the refractive index (n ₃ ) of the second bank layer 142 are n ₁ < n ₂ < The relationship n ₃ must be satisfied.

When the light source 180 for fingerprint recognition having a long wavelength of 700 nm or more is applied to the organic light emitting display device 100 according to an embodiment of the present invention, the refractive index of the first bank layer 141 is higher than the refractive index of the planarization layer 134. When set to large, part of the light emitted from the fingerprint recognition light source 180 located below the substrate 110 is at the boundary between the planarization layer 134 and the first bank layer 141, which have different refractive indices. It may be reflected in the direction of the light source 180 for fingerprint recognition.

In addition, when the refractive index of the second bank layer 142 is set to be greater than the refractive index of the first bank layer 141, the light passing through the interface between the planarization layer 134 and the first bank layer 141 has a refractive index that is different from that of the other. At the boundary between the differently set first bank layer 141 and the second bank layer 142, part of the light may be reflected again in the direction of the light source 180 for fingerprint recognition.

That is, the light emitted from the fingerprint recognition light source 180 disposed at the bottom of the substrate 110 is partially reflected at the boundary between the planarization layer 134 and the first bank layer 141, which have different refractive indices, and is reflected in the first bank layer 141. A portion of the light passing through the bank layer 141 may be reflected at the boundary between the first bank layer 141 and the second bank layer 142 where the refractive index is set differently.

Accordingly, the light emitted from the light source 180 for fingerprint recognition disposed at the bottom of the substrate 110 passes through the planarization layer 134, the first bank layer 141, and the second bank layer 142 each having different refractive indices. As it passes, some of it is reflected back in the direction of the fingerprint recognition light source 180 and may be blocked by the first bank layer 141 and the second bank layer 142.

In addition, the thickness of the first bank layer 141 of the organic light emitting display device 100 according to an embodiment of the present invention is D, and the light source 180 for fingerprint recognition has a wavelength of 700 nm or more. ) can be set to satisfy the relationship of D=(2m+1)λ/4 when the wavelength is λ and the integer excluding sound is m.

As light passes through media with different refractive indices, transmission and reflection occur at the interface of media with different refractive indices. When light moves from a low refractive index to a high refractive index and is reflected, the phase of the wavelength changes by 180 degrees.

Therefore, when the thickness of the first bank layer 141 of the organic light emitting display device 100 according to an embodiment of the present invention is set to satisfy the relationship of D = (2m + 1) λ / 4, the planarization layer 134 ) and the phase of the light reflected at the boundary between the first bank layer 141 and the first bank layer 141 and the second bank layer 142 are 180 degrees different. As a result, light waves having different and opposite phases may overlap and disappear while causing destructive interference.

Accordingly, the light emitted from the light source 180 for fingerprint recognition disposed at the bottom of the substrate 110 passes through the planarization layer 134, the first bank layer 141, and the second bank layer 142 each having different refractive indices. As it passes, part of the light is reflected back in the direction of the fingerprint recognition light source 180 and is blocked, and the thickness of the first bank layer 141 is set to satisfy the relationship of D = (2m + 1) λ / 4. The reflected light is extinguished by destructive interference, so reflection of light by the metal layer on the substrate 110 can be minimized. Accordingly, the optical density (OD) of the first bank layer 141 and the second bank layer 142 can be improved, and the occurrence of light defects perceived by the user can be minimized.

That is, the organic light emitting display device 100 according to an embodiment of the present invention includes a first bank layer 141 and a second bank layer 142, each made of a material containing black pigment, and a planarization layer 134 ), the first bank layer 141 and the second bank layer 142 are each configured to have different refractive indices. The light emitted from the light source 180 for fingerprint recognition under the substrate 110 is transmitted to the light source 180 for fingerprint recognition at the bottom of the first bank layer 141 and the bottom of the second bank layer 142 due to the difference in refractive index. direction, and the first bank layer 141 is formed to have a specific thickness according to the wavelength of the light source. As a result, the light reflected from the lower part of the first bank layer 141 and the lower part of the second bank layer 142 is extinguished by destructive interference, so that the light emitted from the fingerprint recognition light source 180 is not recognized from the outside. The occurrence of defects can be minimized.

Figure 6 is a diagram showing a cross-sectional structure of an organic light emitting display device according to another embodiment of the present invention.

In describing the organic light emitting display device 200 according to another embodiment of the present invention, overlapping detailed descriptions of components that are the same or corresponding to those in the previously described embodiment will be omitted or simply described.

Referring to FIG. 6 , an organic light emitting display device 200 according to another embodiment of the present invention includes a spacer 246 formed on a partial area of the second bank layer 142.

The spacer 246 is formed by contact with a mask during the deposition process of a plurality of organic layers or an organic light emitting layer (EML) formed in the light emitting part 150 or the forming process of the second electrode 160 on the light emitting part 150. It can play a role in preventing defects from occurring.

The spacer 246 may be made of a transparent material. For example, the transparent material may be made of any one of polyimide, photo acryl, and benzocyclobutene (BCB).

Additionally, the spacer 246 may include black pigment like the first bank layer 141 or the second bank layer 142.

Additionally, when the spacer 246 is made of the same material as the second bank layer 142 and includes black pigment, the second bank layer 142 and the spacer 246 use a halftone mask. It can also be formed simultaneously using a halftone process using a mask. A halftone mask is a mask that has a light-shielding part, a light-transmitting part, and a semi-transmissive part. The light-shielding part is a part that blocks light, the light-transmitting part is a part that transmits light, and the semi-transmissive part transmits light more than the light transmitting part. It refers to a small part. When using such a halftone mask, patterns of different heights can be formed simultaneously by differentially applying the amount of light.

Organic light emitting display devices according to embodiments of the present invention can be described as follows.

An organic light emitting display device according to an embodiment of the present invention includes a thin film transistor on a substrate, a planarization layer covering the thin film transistor, the planarization layer, a first electrode connected to the thin film transistor, and at least a portion of the first electrode, and a planarization layer. It includes a first bank layer on the first bank layer, a second bank layer on the first bank layer, a light-emitting portion including an organic material layer and an organic light-emitting layer on the first electrode, and a second electrode on the light-emitting portion, and the first The bank layer and the second bank layer each include black pigment, the refractive index of the second bank layer is greater than the refractive index of the first bank layer, the thickness of the first bank layer is D, and the wavelength of light of 700 nm or more is λ, negative. When the excluded integer is m, D=(2m+1)λ/4 is satisfied. That is, the organic light emitting display device according to an embodiment of the present invention is configured to include at least two bank layers containing black pigment, thereby minimizing reflection by external light to reduce surface reflection luminance, thereby improving the organic light emitting display device. Outdoor visibility can be improved.

In addition, the organic light emitting display device according to an embodiment of the present invention is configured such that the refractive index of the first bank layer is greater than the refractive index of the planarization layer, the refractive index of the second bank layer is greater than the refractive index of the first bank layer, and the first bank layer Configured to satisfy this specific thickness, the light emitted from the fingerprint recognition light source and reflected from the lower portions of the first and second bank layers is extinguished by destructive interference, preventing the light from the light source from being recognized from the outside. can be minimized.

In addition, in the organic light emitting display device according to an embodiment of the present invention, the first bank layer and the second bank layer formed on the planarization layer block the light emitted from the light source for fingerprint recognition, thereby minimizing the occurrence of defects in which light is recognized from the outside. As a result, the image quality of the organic light emitting display device can be improved.

According to another feature of the present invention, the refractive index of the planarization layer may be smaller than the refractive index of the first bank layer.

According to another feature of the present invention, the first bank layer may be made of one of polyimide, photo acryl, and benzocyclobutene (BCB).

According to another feature of the present invention, the second bank layer may include 4,4-thiodibenzenethiol (TDT)-based epoxy acrylate.

According to another feature of the present invention, the width of the lower end of the second bank layer may be smaller than the width of the upper end of the first bank layer.

According to another feature of the present invention, it further includes a light source located below the substrate, and light can be emitted from the light source toward the substrate.

According to another feature of the present invention, the light source may be a light source for fingerprint recognition having a wavelength of 700 nm or more.

According to another feature of the present invention, it further includes a spacer on a portion of the second bank layer, and the spacer may be made of a transparent material.

According to another feature of the present invention, the transparent material may be one of polyimide, photo acryl, and benzocyclobutene (BCB).

According to another feature of the present invention, when the incident angle of light incident on the organic light emitting display device is 45 degrees, the reflection luminance of the organic light emitting display device at a reflection angle of 30 degrees may be 30 nit or less.

In another aspect, an organic light emitting display device including a thin film transistor and an organic light emitting layer between a first electrode and a second electrode is disposed on a planarization layer covering the thin film transistor and includes a first bank made of a material including black pigment. layer and a second bank layer on the first bank layer, wherein the planarization layer, the first bank layer, and the second bank layer are each formed to have different refractive indices, so that the light emitted from the light source is divided into the first bank layer by the difference in refractive index. The light reflected from the bottom of the bank layer and the second bank layer is reflected in the direction of the light source, and the first bank layer is formed to have a specific thickness according to the wavelength of the light source, so that the light reflected from the bottom of the first bank layer and the second bank layer is As the light emitted from the fingerprint recognition light source is extinguished by destructive interference, the occurrence of defects that are recognized from the outside is minimized. That is, the organic light emitting display device according to an embodiment of the present invention is configured to include at least two bank layers containing black pigment, thereby minimizing reflection by external light to reduce surface reflection luminance, thereby improving the organic light emitting display device. Outdoor visibility can be improved.

In addition, the organic light emitting display device according to an embodiment of the present invention is configured such that the refractive index of the first bank layer is greater than the refractive index of the planarization layer, the refractive index of the second bank layer is greater than the refractive index of the first bank layer, and the first bank layer Configured to satisfy this specific thickness, the light emitted from the fingerprint recognition light source and reflected from the lower portions of the first and second bank layers is extinguished by destructive interference, preventing the light from the light source from being recognized from the outside. can be minimized.

In addition, in the organic light emitting display device according to an embodiment of the present invention, the first bank layer and the second bank layer formed on the planarization layer block the light emitted from the light source for fingerprint recognition, thereby minimizing the occurrence of defects in which light is recognized from the outside. As a result, the image quality of the organic light emitting display device can be improved.

According to another feature of the present invention, the refractive index of the first bank layer may be greater than the refractive index of the planarization layer.

According to another feature of the present invention, the refractive index of the second bank layer may be greater than the refractive index of the first bank layer.

According to another feature of the present invention, it further includes a light source for fingerprint recognition below the first electrode, and the thickness D of the first bank layer is such that the wavelength of the light source for fingerprint recognition having a wavelength of 700 nm or more is λ, a non-negative integer. When is m, D=(2m+1)λ/4 can be satisfied.

According to another feature of the present invention, light with a wavelength of 700 nm or less emitted from a light source for fingerprint recognition may be absorbed by the first bank layer.

According to another feature of the present invention, the first bank layer may be made of one of polyimide, photo acryl, and benzocyclobutene (BCB).

According to another feature of the present invention, the second bank layer may include 4,4-thiodibenzenethiol (TDT)-based epoxy acrylate.

According to another feature of the present invention, it may further include a spacer on the second bank layer, and the spacer may include black pigment.

According to another feature of the present invention, the second bank layer and the spacer can be formed simultaneously through a halftone process.

According to another feature of the present invention, the dielectric constant of the first bank layer may be 7C/m ² or less.

Although 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 may be implemented with various modifications without departing from the technical spirit of the present invention. there is. Accordingly, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for illustrative purposes, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, the embodiments described above should be understood in all respects as illustrative and not restrictive. The scope of protection of the present invention should be interpreted in accordance with the claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of rights of the present invention.

100: Organic light emitting display device
110: substrate
120: thin film transistor
121: Gate electrode
122: semiconductor layer
123: source electrode
124: drain electrode
131: buffer layer
132: Gate insulation layer
133: Interlayer insulation layer
134: Flattening layer
135: contact hole
140: first electrode
141: first bank layer
142: second bank layer
150: light emitting unit
151: hole injection layer
152: hole transport layer
152a: first hole transport layer
152b: second hole transport layer
152c: third hole transport layer
153: Organic light emitting layer
153a: red light emitting layer
153b: green emitting layer
153c: blue emitting layer
154: electron transport layer
160: second electrode
170: protective layer
180: Light source for fingerprint recognition
246: spacer
R: Red sub-pixel area
G: Green sub-pixel area
B: Blue sub-pixel area

Claims (18)

Thin film transistors on a substrate;
A planarization layer on the thin film transistor;
a first electrode on the planarization layer and connected to the thin film transistor;
a first bank layer covering at least a portion of the first electrode and on the planarization layer;
a second bank layer on the first bank layer;
a light-emitting portion including an organic material layer and an organic light-emitting layer on the first electrode; and
It includes a second electrode on the light emitting unit,
At least one of the first bank layer and the second bank layer includes black pigment, and the refractive index of the second bank layer is greater than the refractive index of the first bank layer,
The organic light emitting display device wherein the refractive index of the planarization layer is smaller than the refractive index of the first bank layer.
delete According to claim 1,
The first bank layer is an organic light emitting display device made of one of polyimide, photo acryl, and benzocyclobutene (BCB).
According to claim 1,
An organic light emitting display device in which the second bank layer includes 4,4-thiodibenzenethiol (TDT)-based epoxy acrylate.
According to claim 1,
The organic light emitting display device wherein the width of the lower end of the second bank layer is smaller than the width of the upper end of the first bank layer.
According to claim 1,
Further comprising a light source located below the substrate,
The light is emitted from the light source toward the substrate.
According to claim 6,
The light source is an organic light emitting display device that is a light source for fingerprint recognition having a wavelength of 700 nm or more.
According to claim 1,
The organic light emitting display device further includes a spacer on a portion of the second bank layer, wherein the spacer is made of a transparent material.
According to claim 8,
An organic light emitting display device in which the transparent material is one of polyimide, photo acryl, and benzocyclobutene (BCB).
According to claim 1,
When the incident angle of light incident on the organic light emitting display device is 45 degrees, the organic light emitting display device has a reflection luminance of 30 nit or less at a reflection angle of 30 degrees. An organic light emitting display device comprising a thin film transistor and an organic light emitting layer between a first electrode and a second electrode,
A planarization layer on the thin film transistor;
a first bank layer on the planarization layer and made of a material containing black pigment; and
comprising a second bank layer on the first bank layer,
The refractive index of the first bank layer is greater than the refractive index of the planarization layer, and the refractive index of the second bank layer is greater than the refractive index of the first bank layer.
According to claim 11,
Further comprising a light source for fingerprint recognition below the first electrode,
The thickness D of the first bank layer satisfies D=(2m+1)λ/4 when the wavelength of the fingerprint recognition light source having a wavelength of 700 nm or more is λ and the non-negative integer is m. .
According to claim 12,
An organic light emitting display device in which light with a wavelength of 700 nm or less emitted from the fingerprint recognition light source is absorbed by the first bank layer.
According to claim 11,
The first bank layer is an organic light emitting display device made of one of polyimide, photo acryl, and benzocyclobutene (BCB).
According to claim 11,
An organic light emitting display device in which the second bank layer includes 4,4-thiodibenzenethiol (TDT)-based epoxy acrylate.
According to claim 11,
Further comprising a spacer on the second bank layer,
The spacer is an organic light emitting display device including black pigment.
According to claim 16,
An organic light emitting display device in which the second bank layer and the spacer are formed simultaneously through a halftone process.
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