KR102473160B1 - Organic light emitting display device - Google Patents

Abstract

The present specification provides an organic light emitting display device that reduces color change according to a viewing angle and improves the efficiency of the organic light emitting device by disposing the first optical multilayer film and the second optical multilayer film on the organic light emitting device. In the organic light emitting display device according to an embodiment of the present specification, an organic light emitting element including an anode, a cathode, and an organic light emitting layer, a first optical multilayer film composed of at least three optical layers on the organic light emitting element, and a first optical multilayer film and an organic material layer on the organic material layer, and a second optical multilayer film composed of at least three optical layers on the organic material layer.

Description

Organic light emitting display {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present specification relates to an organic light emitting display device in which a color change according to a viewing angle is reduced and efficiency of an organic light emitting device is improved by disposing a double optical multilayer film on an organic light emitting device.

An active organic light emitting display device includes an organic light emitting device including an organic light emitting layer, an anode, and a cathode, and a driving circuit for providing current to the organic light emitting device. (eg, transistors, capacitors, etc.) are provided. In the organic light emitting display device, holes and electrons respectively injected from an anode and a cathode recombine in the light emitting layer to form excitons, and a phenomenon in which light of a specific wavelength is generated by energy emission of the formed excitons display device used. Therefore, the organic light emitting display device has advantages such as fast response speed, high contrast ratio, light emitting efficiency, luminance, and viewing angle by using organic light emitting elements that emit light themselves.

Light efficiency of an organic light emitting display device is divided into internal efficiency and external efficiency. Internal efficiency depends on the photoelectric conversion efficiency of the organic light emitting material, and external efficiency, also called light coupling efficiency, depends on the refractive index of each layer constituting the organic light emitting device. Among them, the light extraction efficiency of the organic light emitting display device is low compared to other display devices. The reason is that when the light emitted from the organic light-emitting layer is emitted at a critical angle or higher, for example, a layer with a high refractive index such as an anode or an electrode made of indium tin oxide (ITO), a substrate, and an encapsulation This is because total reflection occurs at interfaces between layers having a low refractive index, such as layers, so that extraction to the outside is hindered. Accordingly, in the organic light emitting display device, about 20% of the light substantially emitted from the organic light emitting device may be extracted to the outside.

As mentioned above, light self-emitted by the organic light emitting device passes through various components of the organic light emitting device and comes out of the organic light emitting device. However, among the light emitted from the organic light emitting layer, light that does not come out of the organic light emitting display device and is trapped inside the organic light emitting display device exists. In this case, light extraction efficiency is lowered because reflection, absorption, scattering, and refraction occur due to interfaces having different refractive indices on the light emitting surface of the organic light emitting device. It becomes a problem.

In order to solve this problem of light extraction efficiency, a strong microcavity effect is generated in the organic light emitting device by varying the thickness and refractive index of the organic light emitting layers disposed in the organic light emitting device or by adding an organic layer to increase light efficiency. method can be used. However, when the thickness and refractive index of the organic light emitting layer are different or an organic layer is added to the organic light emitting layer, the microcavity effect becomes stronger, and the color of the emitted light changes according to the viewing angle, and the emitted light is linear, preventing it from having a Lambertian distribution. do. Here, the strong microcavity may mean a state in which the intensity of light is increased while narrowing the half width of the main peak wavelength. A trade-off relationship appears in which frontal light efficiency and color purity are improved when strong microcavities are used, while light efficiency at a viewing angle is reduced and color change greatly occurs according to a viewing angle.

The inventors of the present specification form an optical multilayer film capable of functioning as an optical resonator on the light emitting surface of an organic light emitting display device to reduce color shift according to a viewing angle and improve the efficiency of an organic light emitting device. Invented a display device.

The problem to be solved according to an embodiment of the present specification is that the stacking order of the optical layers forming the optical multilayer film is determined according to the refractive index, so that the light incident to the optical multilayer film due to primary interference within the organic light emitting device undergoes secondary interference within the optical multilayer film. It is to provide an organic light emitting display device capable of causing a weak microcavity effect and increasing a full width at half maximum (FWHM) of a main peak wavelength of light. In this case, the weak microcavity may mean a state in which a viewing angle characteristic is less affected by increasing the half width of the main peak wavelength. Accordingly, a color change according to a viewing angle may be reduced by applying a structure for generating a weak microcavity effect.

And, a problem to be solved according to an embodiment of the present specification is to provide an organic light emitting display device that reduces color change according to a viewing angle while maintaining the role of a protective layer protecting an organic light emitting device by forming a double optical multilayer film.

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

In the organic light emitting display device according to an embodiment of the present specification, an organic light emitting element including an anode, a cathode, and an organic light emitting layer, a first optical multilayer film composed of at least three optical layers on the organic light emitting element, and a first optical multilayer film By including an organic material layer on the organic material layer and a second optical multilayer film composed of at least three optical layers on the organic material layer, color change according to a viewing angle of the organic light emitting display device may be reduced and efficiency of the organic light emitting device may be improved.

Other embodiment specifics are included in the detailed description and drawings.

Embodiments of the present specification, by disposing a double optical multilayer film on the organic light emitting device, it is possible to improve the efficiency and reliability of the organic light emitting device by widening the half width of light emitted from the organic light emitting device and reducing color change according to the viewing angle. .

In addition, in the embodiments of the present specification, the plurality of optical layers constituting the optical multilayer film alternately arrange a high refractive index optical layer and a low refractive index optical layer in order from the layer adjacent to the cathode, thereby passing through the organic light emitting device. By causing light to cause a plurality of secondary interferences, a color change according to a viewing angle may be reduced and efficiency of the organic light emitting device may be improved.

In addition, embodiments of the present specification form silicon oxynitride (SiON) optical layers having a relatively small refractive index among the optical layers constituting the optical multilayer film, thereby reducing the generation of hydrogen (H ₂ ) generated during the formation of the optical layer. There is an effect of suppressing the deterioration of the organic light emitting layer by suppressing.

In addition, embodiments of the present specification have an effect of reducing color change according to a viewing angle and preventing an optical multilayer film from being separated from an organic light emitting device during product reliability evaluation by forming a capping layer with a thickness of 5 nm or less.

In addition, in the embodiments of the present specification, the refractive index difference between the optical layers constituting the optical multilayer film is formed to be 0.01 or more and 0.6 or less, thereby preventing the peeling of the optical layer due to the difference in expansion coefficient according to the difference in refractive index between the optical layers during reliability evaluation. can do.

Since the content of the specification described in the problem to be solved, the problem solution, and the effect above does 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 specification.

1 is a cross-sectional view illustrating an organic light emitting display device according to an exemplary embodiment of the present specification.
2 is a cross-sectional view showing an organic light emitting display device to which an optical multilayer film according to a first embodiment of the present specification is applied.
3 is a cross-sectional view illustrating an organic light emitting display device to which an optical multilayer film according to a second exemplary embodiment of the present specification is applied.
4A to 4D are graphs illustrating color coordinate change amounts of white light according to viewing angles in right, upper, left, and lower directions from the center of an organic light emitting display device as comparative examples.
5A to 5D are graphs illustrating color coordinate change amounts of white light according to viewing angles in right, upper, left, and lower directions from the center of an organic light emitting display device as examples.

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

The shapes, sizes, ratios, angles, numbers, etc. disclosed in the drawings for explaining the embodiments of this specification are illustrative, so this specification is not limited to the matters shown. Like reference numbers designate like elements throughout the specification. In addition, in describing the present specification, if it is determined that a detailed description of a related known technology may unnecessarily obscure the subject matter of the present specification, the detailed description will be omitted. When 'includes', 'has', 'consists of', etc. mentioned in this specification is used, other parts may be added unless 'only' is used. In the case where a component is expressed in the singular, the case including the plural is included unless otherwise explicitly stated.

In interpreting the components, even if there is no separate explicit description, it is interpreted as including the error range.

In the case of a description of a positional relationship, for example, 'on top of', 'on top of', 'at the bottom of', 'next to', etc. Or, unless 'directly' is used, one or more other parts may be located between the two parts.

In the case of a description of a temporal relationship, for example, when a temporal precedence relationship is described as 'after', 'continue to', 'after ~', 'before', etc., 'immediately' or 'directly' As long as ' is not used, non-continuous cases may also be included.

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

Each feature of the various embodiments of the present specification can be partially or entirely combined or combined with each other, technically various interlocking and driving are possible, and each embodiment can be implemented independently of each other or can be implemented together in an association relationship. may be

Hereinafter, an organic light emitting display device according to an exemplary embodiment of the present specification will be described with reference to the accompanying drawings.

1 is a cross-sectional view showing an organic light emitting display device according to a first embodiment of the present specification.

An organic light emitting display device 1000 includes a substrate 104, an organic light emitting device 100 disposed on the substrate 104, a capping layer 110, a first optical multilayer film 120, an organic material layer 140, and a second An optical multilayer film 150 is included.

A driving circuit for providing current to the organic light emitting device 100 may be disposed on the substrate 104 , and the driving circuit may include a transistor, a capacitor, and the like. In this case, the driving circuit may be formed to correspond to a plurality of subpixels formed on the substrate 104 and is connected to the anode 101 of the organic light emitting device 100 .

The substrate 104 may be made of an insulating material, for example, glass, or polyimide, acryl, polyacrylate, polycarbonate, polyether, or sulfonic acid. It may be made of a flexible film made of (sulfonic acid)-based material or silicon oxide (SiOx), but is not limited thereto.

The organic light emitting device 100 disposed on the substrate 104 includes an anode 101 , an organic light emitting layer 102 , and a cathode 103 . In this case, a hole injection layer and a hole transport layer may be included between the organic light emitting layer 100 and the anode 101, and an electron transport layer and an electron injection layer may be included between the organic light emitting layer 100 and the cathode 103. However, it is not limited thereto. In addition, the organic light-emitting layer 102 is a light-emitting layer that emits red, blue, green, or colors similar thereto, and may have a single-layer structure in which one light-emitting layer is formed, and two or more light-emitting layers are provided, and a charge generation layer ( It may also be a tandem structure including a charge generation layer (CGL).

Light emitted from the organic light emitting layer 102 may cause first order interference 131 between the anode 101 and the cathode 103 . For example, the organic light emitting diode 100 may have a structure and thickness considering a microcavity distance between the anode 101 and the cathode 103 according to the wavelength of light emitted from the organic light emitting layer 102 . Microcavity refers to the fact that the light emitted from the light emitting layer is amplified while repeating reflection and re-reflection between the anode 101 and the cathode 103 to cause constructive interference, thereby improving luminous efficiency. In this case, the organic light emitting layer 102 may be formed separately for each sub-pixel, and the distance between the anode 101 and the cathode 103 may be formed differently according to the color emitted by each sub-pixel. Also, in the case of an organic light emitting display device using white light, the organic light emitting layer 102 may be commonly formed in a plurality of subpixels.

As mentioned above, the anode 101 may be separately disposed for each sub-pixel, and is an electrode supplying or transferring holes to the organic light emitting layer 102, and is an electrode of a transistor disposed on the substrate 104. connected to the source or drain.

In the case of the organic light emitting display device 1000 of the top emission type, the plurality of anodes 101 smoothly reflect light emitted from the organic light emitting layer 102 to the anode 101 in an upward direction (or cathode 103). passing direction) may include a reflective layer to be emitted. For example, the anode 101 may have a two-layer structure in which a transparent layer and a reflective layer are stacked, or a three-layer structure in which a transparent layer, a reflective layer, and a transparent layer are stacked. The transparent layer may be made of a transparent conductive oxide material such as indium tin oxide (ITO) or indium zinc oxide (IZO), and the reflective layer may be made of copper (Cu), silver (Ag), or palladium (Pd). , may be made of metal materials such as aluminum (Al), platinum (At), gold (Au), chromium (Cr), tungsten (T), molybdenum (Mo), titanium (Ti), iridium (Ir), etc. . Alternatively, the anode 101 may be a single layer composed of a material or structure having characteristics of a transparent layer and a reflective layer.

The cathode 103 is commonly disposed in a plurality of sub-pixels and is an electrode supplying or transferring electrons to the organic light emitting layer 102 .

In the case of the organic light emitting display device 1000 of the top emission type, the cathode 103 has a transparent characteristic so that light emitted from the organic light emitting layer 102 can pass therethrough. For example, the cathode 103 may be formed of a very thin metal material such as silver (Ag), magnesium (Mg), or an alloy thereof. Alternatively, like the transparent layer of the anode 101, it may be made of a transparent conductive oxide material such as indium tin oxide or indium zinc oxide.

The strong microcavity effect, that is, the light emitted from the organic light emitting device 100 by the first order interference 131 has an effect of improving the luminous efficiency, but as the intensity of light increases due to the strong microcavity effect, the organic light emitting display device A problem in which color change according to a viewing angle of (1000) is lowered may occur. In the strong microcavity effect, since the intensity of light emitted from the organic light emitting diode 100 increases and the half width of the main peak wavelength of light decreases, the frontal efficiency of the organic light emitting display device 1000 increases, but the viewing angle characteristic deteriorates. Therefore, in order to reduce color change according to viewing angle and increase the efficiency of the organic light emitting device 100 by widening the half width of the main peak wavelength of light while maintaining the intensity of light of the organic light emitting display device 1000, the organic light emitting diode according to an embodiment is increased. In the display device 1000 , the first optical multilayer film 120 and the second optical multilayer film 150 may be disposed on a surface from which light emitted from the organic light emitting device 100 is emitted. The first optical multilayer film 120 and the second optical multilayer film 150 will be described later, and then the capping layer 110 will be described.

A capping layer 110 may be disposed between the organic light emitting diode 100 and the first optical multilayer film 120 . The capping layer 110 may serve to block the inflow of oxygen and moisture from the outside by covering the organic light emitting device 100 . However, when the capping layer 110 is formed thickly, for example, to a thickness of about 40 nm to improve the reliability of the organic light emitting device 100, the color of the light emitted from the organic light emitting display device 1000 depends on the viewing angle. Big changes can happen. In addition, when the capping layer 110 is removed to eliminate color change according to the viewing angle caused by the capping layer 110, the first optical multilayer film 120 and the second optical multilayer film 120 and the second A defect in which the optical multilayer film 150 is separated from the organic light emitting device 100 may occur.

In general, after a product is completed, a reliability evaluation is performed to evaluate the reliability of the product. Reliability evaluation is to check the deformation of the product in appearance or the abnormality of the screen during operation when it is left for several hours to tens of hours in a chamber of high temperature / high humidity, for example, 50 / 90% or 60 / 80% environment. As an evaluation, by conducting a reliability evaluation, products that can withstand high temperature/high humidity environments can be shipped. Temperature or humidity for reliability evaluation is only described as an example, and does not limit the contents of the present specification.

During reliability evaluation of the organic light emitting display device 1000 without the capping layer 110, the organic light emitting layer 102 made of an organic material and the first optical multilayer film 120 made of an inorganic material have different expansion rates in a high temperature/high humidity environment. Because of the difference, a gap may occur between the organic light emitting device 100 including the organic light emitting layer 102 and the first optical multilayer film 120, resulting in a separation defect. Accordingly, the capping layer 110 is disposed between the organic light emitting device 100 and the first optical multilayer film 120 to allow the first optical multilayer film 120 to adhere to the organic light emitting device 100 . In this case, the capping layer 110 is a functional layer formed thin enough to have little optical effect, the thickness of the capping layer 110 may be 5 nm or less, and may be an insulating layer made of an organic material or an inorganic material. Accordingly, the capping layer 110 has an effect of preventing the first optical multilayer film 120 from being separated from the organic light emitting device 100 .

An arrow in FIG. 1 shows a path of light emitted from the organic light emitting layer 102 in front, and reflection of light generated at the interface between the organic light emitting layer 102, the anode 101, and the cathode 103 in the organic light emitting device 100. The first order interference 131, which is the interference of light generated within the organic light emitting device 100, and the first optical multilayer film 120 and the second optical multilayer film 150 at the interface of the optical layers having different refractive indices Secondary interference 132 due to reflection of light is shown.

Since the first optical multilayer film 120 is formed to have a refractive index greater than that of the cathode 103, the light emitted through the cathode 103 has a refractive index greater than the refractive index of the cathode 103. The light 132A reflected at the interface between the first optical multilayer film 120 and the cathode 103 and reflected at the interface between the first optical multilayer film 120 and the cathode 103 causes secondary interference within the first optical multilayer film 120. . In this case, the optical effect of the capping layer 110 disposed between the first optical multilayer film 120 and the cathode 103 on the light emitted through the cathode 103 is negligibly small.

By generating secondary interference 132A of light using the first optical multilayer film 120 , a color change according to a viewing angle of the organic light emitting display device 1000 may be reduced. In this case, the weak microcavity effect can be improved by including the plurality of optical layers in the first optical multilayer film 120 .

By disposing the second optical multilayer film 150 on the first optical multilayer film 120 , color change according to the viewing angle of the organic light emitting display device 1000 may be further improved. In addition, the second optical multilayer film 150 is disposed on the first optical multilayer film 120 to prevent penetration of moisture and oxygen into the organic light emitting device 100 and improve reliability of the organic light emitting device 100. have. The first optical multilayer film 120 and the second optical multilayer film 150 are inorganic insulating layers and may be made of any one or more of silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxynitride (SiON), Not limited to this.

An organic material layer 140 may be disposed between the first optical multilayer film 120 and the second optical multilayer film 150 . The organic layer 140 is an organic insulating layer and may be formed of a polymer. The organic material layer 140 may be formed by an inkjet printing method, but is not limited thereto. The organic material layer 140 is also called a particle covering layer (PCL) and serves to cover foreign matter. In this case, the foreign material is a foreign material that may occur during the process of forming the first optical multilayer film 120 or the second optical multilayer film 150, for example, after forming the first optical multilayer film 120, the second optical multilayer film ( 150), dust in the air may adhere to the first optical multilayer film 120 during the moving process. In this case, when the second optical multilayer film 150 made of an inorganic insulating material is disposed on the first optical multilayer film 120 without the organic material layer 140 in a state in which foreign matter is attached to the surface of the first optical multilayer film 120, inorganic Since the insulating material does not have high adhesion to the foreign matter attached to the surface of the first optical multilayer film 120, a gap may be formed around the foreign material, and the second optical multilayer film 150 may be peeled off due to the formation of the gap. Therefore, by disposing the organic material layer 140 made of an organic material between the first optical multilayer film 120 and the second optical multilayer film 150, the foreign matter and the surroundings of the foreign matter are covered to prevent the second optical multilayer film 150 from being peeled off. can do. In this case, the thickness of the organic layer 140 may be 5 μm or more and 20 μm or less, but is not limited thereto. When the organic material layer 140 is formed by the inkjet printing method, the thickness may be 8 μm or less, but is not limited thereto.

2 is a cross-sectional view showing an organic light emitting display device to which an optical multilayer film according to a first embodiment of the present specification is applied. Since the organic light emitting display device 1001 of FIG. 2 has the same components other than the first optical multilayer film 120 and the second optical multilayer film 150 of FIG. 1 , the description thereof may be omitted or simplified.

The first optical multilayer film 121 according to the first embodiment of the present specification includes a first optical layer 121A, a second optical layer 121B, and a third optical layer 121C. The first optical layer 121A is disposed on the cathode 103 . The first optical layer 121A may be formed to have a refractive index greater than that of the cathode 103, and the light emitted through the cathode 103 has a refractive index greater than that of the cathode 103. The first optical layer ( 121A) and the cathode 103, and the light 132A' reflected at the interface between the first optical layer 121A and the cathode 103 is reflected in the first optical multilayer film 121 by 2 Car interference occurs. In this case, the optical effect of the capping layer 110 disposed between the first optical layer 121A and the cathode 103 on the light emitted through the cathode 103 is negligibly small.

When light having an incident angle of 0° (perpendicular to the incident plane) is incident from a material having a low refractive index to a material having a high refractive index, reflected light is generated at the boundary between the material having a low refractive index and the material having a high refractive index. In this case, the reflected light generated is greater than the amount of reflected light generated when light having an incident angle of 0° is incident from a material having a high refractive index to a material having a low refractive index. Accordingly, by incident light from a material having a low refractive index to a material having a high refractive index, the amount of reflected light is increased, so that secondary interference by the reflected light can occur efficiently.

Subsequently, a second optical layer 121B is disposed on the first optical layer 121A. The second optical layer 121B may be formed to have a refractive index smaller than that of the first optical layer 121A.

In addition, a third optical layer 121C is disposed on the second optical layer 121B. The third optical layer 121C may be formed to have a higher refractive index than that of the second optical layer 121B. Accordingly, the light emitted through the second optical layer 121B is reflected at the interface between the third optical layer 121C having a higher refractive index than the second optical layer 121B and the second optical layer 121B ( 132A″), and the light 132A″ reflected at the interface between the third optical layer 121C and the second optical layer 121B causes secondary interference within the first optical multilayer film 121 . For example, the first optical layer 121A may have a refractive index of 1.94, the second optical layer 121B may have a refractive index of 1.70, and the third optical layer 121C may have a refractive index of 1.85, but are not limited thereto. In addition, the sum of the thicknesses of the first optical layer 121A, the second optical layer 121B, and the third optical layer 121C may be 1 μm, but is not limited thereto. Accordingly, the first optical layer 121A may have a thickness of 0.5 μm, the second optical layer 121B may have a thickness of 0.2 μm, and the third optical layer 121C may have a thickness of 0.3 μm, but are not limited thereto. When each optical layer is formed to a thickness of less than 0.1 μm, the process dispersion of the optical layer increases, so the uniformity of the thickness is rapidly reduced. The values of refractive index and thickness are design values and may include process deviations. For example, the process variation of refractive index may be 2%, and the process variation of thickness may be 6%.

The second optical multilayer film 151 according to the first embodiment of the present specification includes a fourth optical layer 151A, a fifth optical layer 151B, and a sixth optical layer 151C. The fourth optical layer 151A may be formed to have a higher refractive index than the organic layer 140, and the light emitted through the organic layer 140 has a higher refractive index than the organic layer 140. The fourth optical layer ( 151A) and the organic layer 140, and the light 132B' reflected from the interface between the fourth optical layer 151A and the organic layer 140 is 2 Car interference occurs. For example, the refractive index of the organic layer 140 may be 1.5 to 1.6.

Subsequently, a fifth optical layer 151B is disposed on the fourth optical layer 151A. The fifth optical layer 151B may be formed to have a refractive index smaller than that of the fourth optical layer 151A.

In addition, a sixth optical layer 151C is disposed on the fifth optical layer 151B. The sixth optical layer 151C may be formed to have a higher refractive index than that of the fifth optical layer 151B. Accordingly, the light emitted through the fifth optical layer 151B is reflected at the interface between the sixth optical layer 151C having a refractive index greater than the refractive index of the fifth optical layer 151B and the fifth optical layer 151B ( 132B″), and the light 132B″ reflected at the interface between the sixth optical layer 151C and the fifth optical layer 151B causes secondary interference within the second optical multilayer film 151 . The sum of the thicknesses of the fourth optical layer 151A, the fifth optical layer 151B, and the sixth optical layer 151C may be 1 μm, but is not limited thereto. For example, the refractive index and thickness of each of the fourth optical layer 151A, the fifth optical layer 151B, and the sixth optical layer 151C are the first optical layer 121A, the second optical layer 121B, and the same refractive index and thickness of the third optical layer 121C, but are not limited thereto.

In the organic light emitting display device 1001 according to the first embodiment, light reflected from the interface between the cathode 103 and the first optical layer 121A and the interface between the second optical layer 121B and the third optical layer 121C (132A′, 132A″) causes secondary interference in the first optical multilayer film 121, and the interface between the organic layer 140 and the fourth optical layer 151A and the fifth optical layer 151B and the sixth optical layer When the second optical multilayer film 151 is not disposed or the second optical multilayer film 151 is not disposed or the second optical multilayer film 151 is caused by secondary interference of the lights 132B' and 132B'' reflected at the interface of the layer 151C. Since the weak microcavity effect is relatively improved compared to the case where the optical multilayer film 151 is arranged as a single layer, color change according to the viewing angle of the organic light emitting display device 1001 can be reduced and the efficiency of the organic light emitting device 100 can be improved. have.

In addition, by disposing the second optical multilayer film 151 on the first optical multilayer film 121, sealing reliability of the organic light emitting device can be improved. In this case, the reliability of encapsulation means the degree to which the organic light emitting device can be protected from oxygen or moisture introduced from the outside.

3 is a graph showing an organic light emitting display device to which an optical multilayer film according to a second exemplary embodiment of the present specification is applied. Since the organic light emitting display device 1002 of FIG. 3 has the same components other than the first optical multilayer film 120 and the second optical multilayer film 150 of FIG. 1 , the description thereof may be omitted or simplified.

The first optical multilayer film 122 according to the second embodiment of the present specification includes a first additional optical layer in addition to the first optical layer 121A, the second optical layer 121B, and the third optical layer 121C ( 121D), and the second optical multilayer film 152 according to the second embodiment of the present specification is in addition to the fourth optical layer 151A, the fifth optical layer 151B, and the sixth optical layer 151C. A second additional optical layer 151D is included. Configuration of the first optical layer 121A, the second optical layer 121B, the third optical layer 121C, the fourth optical layer 151A, the fifth optical layer 151B, and the sixth optical layer 151C Elements may be omitted because they overlap with the description of FIG. 2 .

The first additional optical layer 121D may be disposed on the third optical layer 121C. The refractive index of the first additional optical layer 121D may be formed to be smaller than the refractive index of the third optical layer 121C, and light passing through the third optical layer 121C passes through the first additional optical layer 121D. It is allowed to enter the second optical multilayer film 152 . Since light passing through the third optical layer 121C additionally passes through one interference layer, color change with respect to a viewing angle is reduced.

In addition, the second additional optical layer 151D may be disposed on the sixth optical layer 151C. The refractive index of the second additional optical layer 151D may be formed to be smaller than the refractive index of the sixth optical layer 151C, and light passing through the sixth optical layer 151C passes through the second additional optical layer 151D. allow light to radiate out. Similar to the first to fourth optical layers 121D, the second additional optical layer 151D also allows the light passing through the sixth optical layer 151C to pass through the second additional optical layer 151D, thereby reducing the color change with respect to the viewing angle. can be further improved.

The first optical layer 121A and the second optical layer 121B, the second optical layer 121B and the third optical layer 121C, the third optical layer 121C and the first additional optical layer 121D, Refractive indices of the 4 optical layers 151A and the fifth optical layer 151B, the fifth optical layer 151B and the sixth optical layer 151C, and the sixth optical layer 151C and the second additional optical layer 151D When the difference is large, peeling may occur due to the difference in expansion coefficient between optical layers having a large difference in refractive index during reliability evaluation, so the difference in refractive index between optical layers may be formed to be 0.01 or more and 0.6 or less.

In this case, the sum of the thicknesses of the first optical layer 121A, the second optical layer 121B, the third optical layer 121C, and the first additional optical layer 121D may be 1 μm, but is not limited thereto. don't The second optical multilayer film 152 may be composed of optical layers having the same thickness and refractive index as the first optical multilayer film 122, but is not limited thereto.

The first and second optical multilayer films 121 and 151 according to the first embodiment and the first and second optical multilayer films 122 and 152 according to the second embodiment described above are compared to optical multilayer films composed of two optical layers. By further including one or two optical layers, color change according to a viewing angle of the organic light emitting display device may be reduced.

For example, when a plurality of layers are added, color change according to a viewing angle can be reduced, but frontal efficiency or luminance of the organic light emitting display device may be reduced. Therefore, it is important to determine the number of optical layers to achieve the effect of the present specification without causing problems such as frontal efficiency or luminance of the organic light emitting display device.

The optical multilayer films 121, 122, 151, and 152 composed of three or four optical layers may be effective in the following respects. When a white screen is displayed on an organic light emitting display device, it is possible to prevent the white screen from being yellow, and to prevent the optical multilayer film from being peeled off during reliability evaluation due to a difference in refractive index. In addition, the more optical layers are formed, the greater the possibility of occurrence of haze in the optical multilayer film, which may affect the luminance of a display device. The smaller the number of optical layers, the lower the possibility of occurrence of haze. In addition, as the number of optical layers is reduced, the time required to clean the optical layer deposition chamber is reduced, so the process time can be shortened.

Therefore, in the present specification, by using a minimum optical layer, the amount of light reflected by the difference in refractive index of the optical layer is maximized so that the light passing through the organic light emitting device 100 can cause secondary interference.

The plurality of optical layers constituting the first optical multilayer films 121 and 122 and the second optical multilayer films 151 and 152 according to an embodiment of the present specification are made of silicon nitride (SiNx), silicon oxide (SiOx), or silicon oxide. It may be made of any one or more than one of nitride (SiON). Among them, at a wavelength between 400 nm and 700 nm, the refractive index of silicon oxide (SiOx) and silicon nitride oxide (SiON) is about 1.46 or more and 1.5 or less, and the refractive index of silicon nitride (SiNx) is about 1.9 or more and 2.3 or less, so silicon oxide The refractive index of (SiOx) and silicon oxynitride (SiON) is smaller than that of silicon nitride (SiNx). In addition, oxygen atoms included in silicon oxide (SiOx) and silicon oxynitride (SiON) are combined with hydrogen (H ₂ ) generated during the formation of the optical layer, so that hydrogen (H ₂ ) penetrates into the organic light emitting device 100 and organically Deterioration of the light emitting device 100 can be prevented.

Therefore, by forming the optical layers having a small refractive index among the optical layers constituting the optical multilayer films 120, 121, 122, 150, 151, and 152 with silicon oxide (SiOx) or silicon oxynitride (SiON), when forming the optical layer Deterioration of the organic light emitting layer may be prevented by suppressing generation of hydrogen (H ₂ ). For example, a second optical layer 121B adjacent to the first optical layer 121A and having a lower refractive index than the first optical layer 121A and a third optical layer 121C adjacent to the third optical layer 121C The first additional optical layer 121D having a lower refractive index may be formed of silicon oxide (SiOx) or silicon oxynitride (SiON). Similarly, the fifth optical layer 151B and the sixth optical layer 151C are adjacent to the fourth optical layer 151A and have a lower refractive index than the fourth optical layer 151A and have a refractive index lower than the sixth optical layer 151C. The small second additional optical layer 151D may be formed of silicon oxide (SiOx) or silicon oxynitride (SiON).

The first optical multilayer film 121 and the second optical multilayer film 151 each composed of three optical layers according to the first embodiment mentioned above, and the first optical multilayer film composed of four optical layers each according to the second embodiment. 122 and the second optical multilayer film 152 may be disposed by mixing with each other. For example, an encapsulation structure of an organic light emitting display device may be formed by disposing the second optical multilayer film 152 according to the second embodiment on the first optical multilayer film 121 according to the first embodiment. Alternatively, the encapsulation structure of the organic light emitting display device may be formed by disposing the second optical multilayer film 151 according to the first embodiment on the first optical multilayer film 122 according to the second embodiment. In this case, the encapsulation structure means layers disposed on the organic light emitting device to protect the organic light emitting device from moisture and oxygen introduced from the outside. According to an embodiment of the present specification, the encapsulation structure includes a capping layer, a first optical multilayer film, It includes an organic material layer and a second optical multilayer film.

4A to 4D are graphs showing color coordinate change amounts of white light according to viewing angles in right, upper, left, and lower directions from the center of an organic light emitting display device as comparative examples, and FIGS. 5A to 5D are graphs showing a first embodiment. , is a graph showing color coordinate change amounts of white light according to viewing angles in right, upper, left, and lower directions from the center of the organic light emitting display device. In this case, the right, top, left, and bottom directions of the organic light emitting display device may be represented by azimuth angles of 0°, 90°, 180°, and 270°, respectively. The color coordinate variation (Δu'v') refers to the difference between the color coordinates when viewed from the front and the color coordinates at the viewing angle, and the color coordinates (u'v') refers to the 1976 UCS chart coordinates defined in CIE 15.2 of the International Commission on Illumination. The viewing angles measured in FIGS. 4A to 4D and FIGS. 5A to 5D range from 0° to 60°, and the viewing angle at the starting position X is 0°.

The conditions of the layer disposed on the organic light emitting device for the comparative examples and the first embodiment of FIGS. 4A to 4D and FIGS. 5A to 5D are shown in [Table 1] below.

capping layer First optical multilayer film organic layer Second optical multilayer film comparative example The presence or absence O SiNx SiON O SiNx thickness 40nm 0.9㎛ 0.1㎛ 8㎛ 1㎛ Example 1 The presence or absence O SiNx SiON SiNx O SiNx SiON SiNx thickness 5nm 0.5nm 0.2nm 0.3nm 8㎛ 0.5nm 0.2nm 0.3nm

In the organic light emitting display device formed as shown in [Table 1], in the case of Comparative Example, the first optical multilayer film is formed of two inorganic insulating layers and the second optical multilayer film is formed of one inorganic insulating layer, and in the case of the first embodiment, the first optical multilayer film and The second optical layer includes three optical layers each having a different thickness, and the three optical layers are arranged in order from a layer having a high refractive index on the capping layer, a layer having a high refractive index, a layer having a low refractive index, and a layer having a high refractive index, and the thickness is and a capping layer of 5 nm. The capping layer, the first optical multilayer film, the organic material layer, and the second optical multilayer film shown in [Table 1] are sequentially stacked on the organic light emitting device.

Referring to FIG. 4A , a graph in which color coordinates of white light are measured by forming a viewing angle in the right direction (azimuth angle 0°) in a state of looking at the front from the center of the organic light emitting display device, and the maximum value (Δu) of color coordinate change according to the viewing angle 'v'_0R) is about 0.027.

Referring to FIG. 4B , a graph in which color coordinates of white light are measured by forming a viewing angle in an upward direction (azimuth angle 90°) in a state in which the front is viewed from the center of the organic light emitting display device, and the maximum value (Δu) of the color coordinate change according to the viewing angle 'v'_90R) is about 0.023.

Referring to FIG. 4C , it is a graph in which color coordinates of white light are measured by forming a viewing angle in the left direction (azimuth angke 180°) in a state of looking at the front from the center of the organic light emitting display device, and the maximum value of color coordinate change according to the viewing angle (Δu 'v'_180R) is about 0.028.

Referring to FIG. 4D , it is a graph in which color coordinates of white light are measured by forming a viewing angle in a downward direction (azimuth angle 270°) in a state of looking at the front from the center of the organic light emitting display device, and the maximum value (Δu) of the color coordinate change according to the viewing angle 'v'_270R) is about 0.024.

The graphs of FIGS. 5A to 5D are the results of applying the structure of the first embodiment shown in [Table 1].

Referring to FIG. 5A, a graph in which color coordinates of white light are measured by forming a viewing angle in the right direction (azimuth angle 0°) in a state of looking at the front from the center of the organic light emitting display device, and the maximum value (Δu) of color coordinate change according to the viewing angle 'v'_0E) is about 0.019.

Referring to FIG. 5B, it is a graph in which color coordinates of white light are measured by forming a viewing angle in an upward direction (azimuth angle 90°) in a state of looking at the front from the center of the organic light emitting display device. The value (Δu'v'_90E) is about 0.018.

Referring to FIG. 5C, a graph in which color coordinates of white light are measured by forming a viewing angle in the left direction (azimuth angle 180°) in a state of viewing the front from the center of the organic light emitting display device, and the maximum value (Δu) of the color coordinate change according to the viewing angle 'v'_180E) is about 0.020.

Referring to FIG. 5D , it is a graph in which color coordinates of white light are measured by forming a viewing angle in a downward direction (azimuth angle 270°) in a state of looking at the front from the center of the organic light emitting display device, and the maximum value (Δu) of the color coordinate change according to the viewing angle 'v'_270E) is about 0.017.

When the maximum value of the color coordinate change amount of the Comparative Example and the First Example is compared according to the direction forming the viewing angle, it can be seen that the value of the First Example is smaller than the value of the Comparative Example. The maximum value of the color coordinate change of white light emitted from the organic light emitting display device of Comparative Example in which the first optical multilayer film and the second optical multilayer film are a single layer or two layers is the optical layer having a high refractive index, the optical layer having a low refractive index, and the optical layer having a high refractive index. The color coordinate change amount of white light emitted from the organic light emitting display device of the first embodiment including the first optical multilayer film and the second optical multilayer film composed of optical layers having is greater than the maximum value. Therefore, when the first embodiment is applied, there is an effect of reducing color change according to the viewing angle and improving the efficiency of the organic light emitting device.

An organic light emitting display device according to an embodiment of the present specification can be described as follows.

In the organic light emitting display device according to an embodiment of the present specification, an organic light emitting element including an anode, a cathode, and an organic light emitting layer, a first optical multilayer film composed of at least three optical layers on the organic light emitting element, and a first optical multilayer film By including an organic material layer on the organic material layer and a second optical multilayer film composed of at least three optical layers on the organic material layer, color change according to a viewing angle of the organic light emitting display device may be reduced and efficiency of the organic light emitting device may be improved.

According to another feature of the present specification, the first optical multilayer film may include a first optical layer on the cathode, a second optical layer on the first optical layer, and a third optical layer on the second optical layer. can

According to another feature of the present specification, the refractive index of the first optical layer is greater than the refractive index of the cathode, the refractive index of the second optical layer is smaller than the refractive index of the first optical layer, and the refractive index of the third optical layer is that of the second optical layer. may be greater than the refractive index.

According to another feature of the present specification, the first optical layer and the third optical layer may be silicon nitride (SiNx).

According to another feature of the present specification, the first optical multilayer film may further include a first additional optical layer on the third optical layer and having a lower refractive index than the third optical layer.

According to another feature of the present specification, the second optical multilayer film may include a fourth optical layer on the organic material layer, a fifth optical layer on the fourth optical layer, and a sixth optical layer on the fifth optical layer. can

According to another feature of the present specification, the refractive index of the fourth optical layer is greater than the refractive index of the organic material layer, the refractive index of the fifth optical layer is smaller than the refractive index of the fourth optical layer, and the refractive index of the sixth optical layer is that of the fifth optical layer. may be greater than the refractive index.

According to another feature of the present specification, the fourth optical layer and the sixth optical layer may be silicon nitride (SiNx).

According to another feature of the present specification, the second optical multilayer film may further include a second additional optical layer on the sixth optical layer and having a lower refractive index than the sixth optical layer.

According to another feature of the present specification, a capping layer may be further included on the cathode.

According to another feature of the present specification, the organic material layer may have a thickness of 5 μm or more and 20 μm or less.

According to another feature of the present specification, each of the first optical multilayer film and the second optical multilayer film may have a thickness of 1 μm or less.

According to another feature of the present specification, each of the first optical multilayer film and the second optical multilayer film may include a plurality of optical layers, and a difference in refractive index between adjacent optical layers among the plurality of optical layers may be 0.01 or more and 0.6 or less.

According to another feature of the present specification, the amount of change in color coordinates according to the viewing angle of the organic light emitting display device may be 0.020 or less.

Although the embodiments of the present specification have been described in more detail with reference to the accompanying drawings, the present specification is not necessarily limited to these embodiments, and may be variously modified and implemented without departing from the technical spirit of the present specification. . Therefore, the embodiments disclosed in this specification are not intended to limit the technical spirit of the present specification, but to explain, and the scope of the technical spirit of the present specification is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of this specification should be construed according to the claims, and all technical ideas within the equivalent range should be construed as being included in the scope of this specification.

1000, 1001, 1002: organic light emitting display device
100: organic light emitting device
101: anode
102: organic light emitting layer
103: cathode
104: substrate
110: capping layer
120, 121, 122: first optical multilayer film
121A: first optical layer
121B: second optical layer
121C: third optical layer
121D: first additional optical layer
131: 1st interference
132: secondary interference
140: organic material layer
150, 151, 152: second optical multilayer film
151A: fourth optical layer
151B: fifth optical layer
151C: 6th optical layer
151D: second additional optical layer

Claims (13)

an organic light emitting device including an anode, a cathode, and an organic light emitting layer;
a first optical multilayer film composed of at least three optical layers on the organic light emitting device;
an organic material layer on the first optical multilayer film; and
A second optical multilayer film composed of at least three optical layers on the organic material layer,
The first optical multilayer film includes a first optical layer on the cathode, a second optical layer on the first optical layer, and a third optical layer on the second optical layer,
The refractive index of the first optical layer is greater than the refractive index of the cathode, the refractive index of the second optical layer is less than the refractive index of the first optical layer, and the refractive index of the third optical layer is greater than the refractive index of the second optical layer. , organic light emitting display. delete delete According to claim 1,
The organic light emitting display device, wherein the first optical layer and the third optical layer are silicon nitride (SiNx). According to claim 1,
The organic light emitting display device of claim 1 , wherein the first optical multilayer film further includes a first additional optical layer on the third optical layer and having a lower refractive index than the third optical layer. According to claim 1,
The second optical multilayer film includes a fourth optical layer on the organic layer, a fifth optical layer on the fourth optical layer, and a sixth optical layer on the fifth optical layer. . According to claim 6,
The refractive index of the fourth optical layer is greater than the refractive index of the organic layer, the refractive index of the fifth optical layer is less than the refractive index of the fourth optical layer, and the refractive index of the sixth optical layer is greater than the refractive index of the fifth optical layer. , organic light emitting display. According to claim 6,
The fourth optical layer and the sixth optical layer are silicon nitride (SiNx), the organic light emitting display device. According to claim 6,
The organic light emitting display device of claim 1 , wherein the second optical multilayer film further includes a second additional optical layer on the sixth optical layer and having a lower refractive index than the sixth optical layer. According to claim 1,
The organic light emitting display device, wherein the thickness of the organic material layer is one in a range of 5 μm to 20 μm. According to claim 1,
The organic light emitting display device, wherein each of the first optical multilayer film and the second optical multilayer film has a thickness of 1 μm or less. According to claim 1,
The first optical multilayer film and the second optical multilayer film are each composed of a plurality of optical layers, and a refractive index difference between adjacent optical layers among the plurality of optical layers is 0.01 or more and 0.6 or less. According to claim 1,
The organic light emitting display device, wherein the color coordinate change amount according to the viewing angle of the organic light emitting display device is 0.020 or less.

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