KR101780725B1 - Anti-reflective organic light emitting diode device - Google Patents

Abstract

An object of the present invention is to simplify the structure of an organic light emitting diode by removing a circular polarizer used for improving contrast and to improve the light efficiency of a device which is the greatest disadvantage of a circular polarizer An organic electroluminescent device, and an organic electroluminescent device. Further, there is provided a device characterized by having no influence on the electrical characteristics of the device when solving such a problem.
For this, the present invention includes an organic light emitting diode device and an anti-reflection thin film formed on the organic light emitting diode device, wherein the external light reflected from the organic light emitting diode device is absorbed by the light reflected from the anti-reflection thin film and the extinction interference or anti- A non-reflective organic light emitting diode device is disclosed.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an anti-reflection organic light emitting diode (OLED)

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anti-reflection organic light emitting diode device having characteristics of improving contrast and light efficiency.

2. Description of the Related Art Recently, a display device has been replaced by a thin portable flat display device. Among the flat panel display devices, an organic light emitting diode (OLED) display device is a self-emission type display device having a wide viewing angle, excellent contrast, and fast response speed. And has advantages of excellent luminance, driving voltage and response speed characteristics, and wide color reproduction range.

Such a flat panel display device has recently been manufactured in a lightweight and thin shape, and is portable, and thus can be used outdoors. When a user views an image through a flat panel display device outdoors, there is a problem that sunlight is reflected on the display device and contrast and visibility deteriorate. Particularly, in the case of an OLED display device, .

In order to solve the above problems, a circular polarizer is disposed on one side of an OLED display. However, since the circular polarizer has a transmittance of about 40 to 45%, it has the advantage of reducing reflection of external light, but it has a disadvantage of reducing light emitted from the inside of the device. In addition, a typical circular polariser consists of a linear polariser and a 90 degree phase delay plate with a total thickness of about 0.3 mm.

Therefore, there is a problem in that it is thicker when applied to a thin display, which is a recent trend, and there is a problem that it is difficult to make an integrated device because an additional process is required because it is disposed outside the device. For this reason, studies for replacing the circular polarizer have recently been made.

Recent studies (US 5049780, US 6411019) show techniques for reducing external light reflections without using a circular polarizer using an optical interference filter. The principle of this optical interference filter is to use a metal-dielectric multi-layered thin film to control the light reflected from each metal layer by adjusting the thickness of the dielectric to 180 degrees. Particularly, by disposing such a multilayer thin film on the rear surface metal electrode layer of the organic light emitting device, it is possible to reduce external light reflected from the metal electrode.

Another alternative is to coat the reflective electrode with a light absorbing material (WO 00/25028, Optic Express V13. P. 1406 (2005), Thin Solid Films V379. P. 195 (2000)). In this method, graphite, black polymer, or the like is used as a material that absorbs light.

However, since the conventional structure as described above reduces the reflectance of the metal electrode located on the back surface of the light emitting layer, the light emitted backward from the light emitting layer is not reflected and is reduced, resulting in a decrease in light efficiency. In addition, the reflectance of the rear metal layer close to the light emitting layer is reduced, and the microcavity phenomenon is reduced, thereby lowering the luminance of the light emitting layer. Therefore, it is impossible to remove the cause of the decrease in the light efficiency, which is the greatest disadvantage of the circular polarizer.

To overcome this problem, a recent study (US 6876018) proposed a structure that reduces the external light using the extinction interference shape with the front metal layer without reducing the reflectance of the back metal electrode. In this case, however, the thickness of the organic layer or the transparent electrode layer between the two metal layers must be adjusted in order to satisfy the extinction interference condition between the rear metal electrode and the front metal layer. In this case, there is a problem that it affects the luminous efficiency and the electrical characteristics due to the thickness variation of the electrode layer and the light emitting layer, and it is a technique which is difficult to apply to an actual device due to such a problem affecting the electrical characteristics.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above problems, and it is an object of the present invention to provide an organic light emitting diode having a simple structure by removing a circular polarizer used for improving contrast and inserting an additional metal- It is possible to solve the problem of decreasing the light efficiency of the device which is the greatest disadvantage of the circular polarizer. In addition to the rear metal layer and the metal electrode layer included in the structure of the conventional organic light emitting diode device, the reflectance of the rear metal layer, The present invention provides an anti-reflection organic light emitting diode device which does not reduce the external light reflection and does not affect the light emission efficiency at all, and does not need to control the thickness of the organic layer and the transparent electrode layer, There is a purpose.

In order to achieve the above object, an anti-reflection organic light emitting diode device according to the present invention includes an organic light emitting diode device and an anti-reflection thin film formed on the organic light emitting diode device.

Wherein the organic light emitting diode device comprises a glass substrate, a rear metal layer formed on the glass substrate, a first electrode formed on the rear metal layer, an organic light emitting layer formed on the first electrode, And a second electrode formed on the organic light emitting layer to be opposite to the first electrode. The anti-reflective thin film may be a metal-dielectric multilayer thin film.

The rear metal layer improves the electrical resistance of the first electrode and the rear metal layer is made of Ag, Al, Mg, Cr, Ti, Ni, W, Au, Ta, Cu, Co, Fe, Or an alloy of the above metals.

The first electrode may be a transparent electrode, and the first electrode may be made of a transparent conductive oxide (TCO) such as indium tin oxide (ITO) or indium zinc oxide (IZO). However, it is also possible to use a transflective electrode coated with a thin metal instead of the transparent electrode.

The second electrode is formed as a semi-transparent metal layer and the second electrode is made of Ag, Al, Mg, Cr, Ti, Ni, W, Au, Ta, Cu, Co, Fe, Or an alloy of the above metals.

The metal-dielectric multilayer thin film may include a phase adjusting dielectric layer formed on the organic light emitting diode device, an absorption / reflection metal layer formed on the phase adjustment layer, and a phase correction dielectric layer formed on the absorption / reflection metal layer.

The absorption / reflection metal layer is formed of a thin metal thin film, and the material of the absorption / reflection metal layer is made of Cr, Ti, Mo, Co, Ni, W, Al, Ag, Au, Cu, Co, Fe, And the thickness of the absorption / reflection metal layer is preferably 6 nm to 15 nm.

Wherein the phase adjustment dielectric layer is a dielectric layer that adjusts the relative phase between light reflected from the second electrode and light reflected from the absorption / reflection metal layer to be in a range of 120 to 240 degrees, and the material of the phase adjustment dielectric layer is SiOx ), SiNx (x? 1), MgF2, CaF2, Al2O3, SnO2, ITO, IZO, ZnO, Ta2O5, Nb2O5, HfO2, TiO2 and In2O3, Is preferably 30 nm to 80 nm.

The reason why the relative phase range between the light reflected from the second electrode and the light reflected from the absorption / reflection metal layer is limited to about 120 to 240 degrees is that even when the relative phase is not exactly 180 degrees, Since the extinction interference phenomenon may occur at about 120 to 240 degrees, preferably at about 150 to 210 degrees, and most preferably when the relative phase is at about 180 degrees, Of course, it can happen.

Wherein the phase correction dielectric layer is a dielectric layer for correcting a relative phase controlled by the phase adjustment dielectric layer when the phase deviates from 180 degrees and the material of the phase correction dielectric layer is SiOx (x? 1), SiNx (x? 1) And the thickness of the phase-correcting dielectric layer may be in the range of 60 nm to 90 nm. The thickness of the phase-compensating dielectric layer may be in the range of 60 nm to 90 nm.

The backside metal layer and the light of the external light reflected from the second electrode may be absorbed in the absorption / reflection metal layer or in the extinction interference with the light reflected from the absorption / reflection metal layer by the phase adjustment dielectric layer and the phase correction dielectric layer.

The metal-dielectric multilayer thin film may be a plurality of two or more.

Light of the external light reflected by the rear metal layer and the second electrode may be canceled or absorbed by the metal-dielectric multilayer thin film.

The metal-dielectric multilayer thin film comprises a dielectric layer and a semi-transmissive metal layer, and the material for the dielectric layer are SiOx (x≥1), SiNx (x≥1 ), MgF 2, CaF 2, Al 2 O 3, SnO 2, ITO , IZO, ZnO, Ta ₂ O ₅ , Nb ₂ O ₅ , HfO ₂ , TiO ₂ and In ₂ O ₃ , and the material of the transflective metal layer is Cr, Ti, Mo, Co, Ni, W, Al, Ag, Au, Cu, Fe, Mg, and Pt, or an alloy of the metal.

As described above, according to the non-reflective organic light emitting diode device of the present invention, the reflection of external light is reduced without using a circular polarizer, so that an additional process is not required, the thickness of the device can be reduced, and an integrated device can be manufactured.

In addition, there is no loss of light lost by the circular polarizer, and the light efficiency is improved. Compared with the organic light emitting device that replaces the conventional circular polarizer, the reflection of the external light without changing the reflectance of the internal metal, the thickness of the light emitting layer, It has an effect of not affecting the electrical characteristics and luminous efficiency of the device.

In addition, although a metal layer is additionally included in addition to the rear surface metal layer and the metal electrode layer included in the conventional organic light emitting diode device, the light emitting efficiency of the device is not affected.

In addition, unlike the existing technology limited to the back light emitting structure, the present invention can be applied to a front light emitting structure.

1 is a schematic view of an organic light emitting diode in the form of a conventional front light emitting structure.
2 is a graph showing the external light reflection of the organic light emitting diode device of the conventional top emission type structure.
3 is a schematic view showing a configuration of a circular polarizer for reducing external light reflection.
4 is a comparative photograph of the front emission OLED according to the presence or absence of the circular polarizer.
5 is a structural view of an anti-reflection organic light emitting diode device according to one embodiment of the present invention.
6 is a graph showing the absorption rate for any metal having a thickness of 10 nm.
7 is a structural view of an anti-reflection organic light emitting diode device including a plurality of metal-dielectric multilayer thin films.
8A and 8B are graphs of the results of Example 1, wherein FIG. 8A is a graph of external light reflection tendency according to the thickness variation of the phase adjustment layer (the thickness of Cr is fixed to 8 nm and the thickness of the phase correction layer SiO2 is fixed to 80 nm) And FIG. 8B is a graph of an external light reflection tendency graph (the thickness of Cr is fixed to 8 nm and the thickness of the phase adjustment layer is fixed to 60 nm) according to the thickness variation of the phase correction layer.
9A and 9B are graphs of results for Example 1, where FIG. 9A is a graph of external light reflection tendency according to the thickness of Cr (the thickness of the phase adjustment layer is 60 nm and the thickness of the phase correction layer is 80 nm) (In this case, the numbers in parentheses indicate relative efficiency ratios (luminance ratios) relative to a conventional organic light emitting diode device having a circular polarizer).
10A and 10B are graphs of results for Example 2. FIG. 10A is a graph showing the external light reflectance according to the Mg: Ag electrode thickness (the thickness of the phase adjustment layer is 60 nm, the thickness of the phase correction layer is 80 nm, Thickness is 6 nm), and Fig. 10B is a graph of change in luminescence intensity according to the thickness of Mg: Ag electrode.
11A and 11B are graphs of results for Example 3. FIG. 11A is a graph showing the external light reflection of the front light emitting device according to the thickness variation of the phase adjusting layer (the thickness of Cr is 10 nm and the thickness of the phase correction layer is 60 nm ), And Fig. 11B is a graph of the intensity change of the device with the change of the phase adjusting layer thickness.
12A and 12B are graphs of results of Example 4, wherein FIG. 12A is a graph of external light reflection tendency (the thickness of the phase adjustment layer and the phase correction layer is 80 nm) Fig. 4 is a graph showing the change in intensity of the device according to the change.
13A and 13B are graphs of results for Example 5, wherein FIG. 13A is a graph showing the external reflection tendency of the device (thickness of the phase adjustment layer SiNx is 50 nm and thickness of the phase correction layer SiO 2 is 70 nm) And Fig. 13B is a graph of change in luminescence intensity of the device according to Ti thickness variation.
14A and 14B are graphs of results for Example 6, wherein FIG. 14A is a graph showing the external reflection tendency of the device according to the change in Mg: Ag thickness (the thickness of the phase adjustment layer SiNx is 50 nm, 70 nm, the absorption / reflection metal layer is Ti having a thickness of 11 nm), and FIG. 14B is a graph of the light emission intensity change of the device according to the Mg: Ag thickness variation.

Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. First, it should be noted that the same components or parts among the drawings denote the same reference numerals whenever possible. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted so as not to obscure the subject matter of the present invention.

1 is a schematic view of an organic light emitting diode in the form of a conventional front light emitting structure.

As shown in FIG. 1, the conventional organic light emitting diode includes a glass substrate, a reflective layer (Ag), a transparent electrode layer (ITO), an organic layer, a metal electrode layer (Mg: Ag), and a capping layer layer or passivation layer. As shown in FIG. 1, the external light incident from the outside is reflected by the metal electrode layer (Mg: Ag) and the reflective layer (Ag), which causes the contrast of the device to deteriorate.

FIG. 2 is a graph showing the external light reflection of the organic light emitting diode device of the conventional top emission type structure, and shows the external light reflectance of the organic light emitting diode device of the conventional top emission type structure shown in FIG. In this case, the luminous reflectance is approximately 45%.

Typically, the contrast in the display device is defined by the following equation (1).

Here, Lon and Loff represent the luminance values of the OLED element when the OLED element is on and off, respectively. Lambient represents the luminance of external light. And RD is a luminous reflectance value of the display defined by the following equation (2). Here, the luminous reflectance is an average reflectance of a display device in a visible light region.

Here, V denotes the spectral curvature function, S denotes the spectrum of the standard light source D65, and R denotes the reflectance of the external light according to the spectrum of the display. Therefore, the luminous reflectance of the conventional OLED element in Fig. 2 for external light is approximately 45%.

In order to reduce such external light reflection, a circular polarizer as shown in FIG. 3 is used in a conventional organic light emitting device to prevent reflection of external light and improve contrast.

The circular polarizer shown in FIG. 3 is composed of a plurality of optical thin films, and the main constituent is a combination of a linear polarizer and a quarter wave plate.

4 is a comparative photograph of the front emission OLED according to the presence or absence of the circular polarizer.

The left side of the figure shows an OLED element not provided with a circular polariser, and the right side shows an OLED element having a circular polariser. It can be seen that it is difficult to use the OLED display in an environment where there is strong external light such as outside sunlight if the circular polarizer is not provided due to the structural characteristics of the OLED.

Here, in the case of a circular polarizer, a linear polarizer is used as a constituent, and in a general linear polarizer, the transmittance is about 40 to 45%, so that light transmitted through the circular polarizer is reduced by about 50% or more. Therefore, when the circular polarizer is used, there is an advantage that the reflection of external light can be reduced, but the light emitted from the inside of the device is absorbed and shrunk. That is, the optical efficiency ratio of the OLED element is reduced.

In addition, a typical circular polarizer has a total thickness of about 0.3 mm. In recent years, when applied to an ultra-thin display, there is a disadvantage that the thickness of the polarizer increases, and since it is disposed outside the device, an additional process is required. There is a dot. For this reason, studies have been made to improve the contrast by eliminating the circular polarizer and reducing the external light reflection of the OLED element.

FIG. 5 is a structural view of an anti-reflection organic light emitting diode device according to the present invention, and is a schematic view of a novel structure of an organic light emitting diode device capable of reducing external light reflection without a circular polarizer.

5, a glass substrate 10, a rear metal layer 20, a first electrode 30, an organic light emitting layer 40, and a second electrode (not shown) are formed on the anti-reflection organic light emitting diode device according to one embodiment of the present invention. Reflective metal layer 70 and a phase correcting dielectric layer 80 are sequentially formed on the organic light emitting diode device and the rear metal layer 20 And the light of the external light reflected by the second electrode 50 are absorbed by the absorption / reflection metal layer 70 or the extinction interference with the light reflected from the absorption / reflection metal layer 70.

The rear metal layer 20 may be an Ag layer improving the electrical resistance of the first electrode 30 which is a transparent anode ITO. The rear metal layer 20 may be made of Ag, Al, Mg, Cr, Ti, Ni, W, Au, Ta, Cu, Co, Fe, Mo and Pt.

The organic light emitting layer 40 is formed on the first electrode 30 and the second electrode 50 is formed on the organic light emitting layer 40 so as to face the first electrode 30, The second electrode 50 is preferably a semitransparent metal layer (Mg: Ag layer) serving as a cathode.

As the material of the second electrode 50, any one selected from the group consisting of Ag, Al, Mg, Cr, Ti, Ni, W, Au, Ta, Cu, Co, .

Next, a metal-dielectric multilayer thin film including a phase-adjusting dielectric layer 60, an absorbing / reflecting metal layer 70, and a phase-correcting dielectric layer 80 will be described.

On the other hand, an OLED having a general top emission structure has a structure in which light emitted from an organic material layer is transmitted through a translucent Mg: Ag layer to emit light to the outside, and a passivation layer layer is formed. Here, the passivation layer is generally formed of an organic material layer, and the passivation layer may be referred to as an OLED having a general top emission structure.

In the present invention, the phase adjustment dielectric layer 60, which may be referred to as a passivation layer, is used for phase matching purposes, an absorption / reflection metal layer 70, which is a thin metal layer, is formed on the phase adjustment dielectric layer 60, A compensating dielectric layer 80 is formed and utilized for phase compensation.

First, the phase-adjusting dielectric layer 60 and the phase-correcting dielectric layer 80 will be described in detail as follows.

In the present invention, an absorption / reflection metal layer (hereinafter, referred to as " OLED element ") in which light of external light reflected from the metal layers (the second electrode 50 and the rear metal layer 20 in the present invention) 70 and the phase correcting dielectric layer 80 to cause optical cancellation interference with the light reflected from the phase-adjusting dielectric layer 60 and the phase-correcting dielectric layer 80.

The optical extinction interference phenomenon referred to herein refers to a phenomenon in which light reflected at the interface is canceled with each other when the reflection amplitudes are equal to each other with a phase of about 180 degrees between them.

Usually, the optical thickness of the phase adjusting dielectric layer 60 and the phase correcting dielectric layer 80 is designed to be close to a quarter wavelength although there is a difference depending on the dispersion of the optical constant depending on the type of the metal.

At this time, the reflected light from the metal layers causes extinction interference, thereby reducing the reflection of external light. Thus, the present invention has the advantage of reducing reflection of external light without additional circular polarizer.

The material of the phase adjustment dielectric layer 60 is SiOx (x? 1), SiNx (x? 1), MgF2, CaF2, Al2O3, SnO2, ITO, IZO, ZnO, Ta2O5, Nb2O5, HfO2, TiO2 In2O3, and the like.

The thickness of the phase adjusting dielectric layer 60 is preferably 30 nm to 80 nm, more preferably 50 nm to 80 nm in the case of SiOx (x? 1), more preferably 30 nm to 80 nm in the case of SiNx More preferably 60 nm.

Since it is difficult to maintain the phase difference of the light reflected by the visible light propagation field at 180 degrees with the phase adjustment dielectric layer 60 alone, the phase correction dielectric layer 80, which serves to compensate for an amount deviating from the phase of 180 degrees according to the wavelength of external light, It is preferable that any one selected from the group consisting of SiOx (x≥1), SiNx (x≥1), MgF2, CaF2, Al2O3, SnO2, ITO, IZO, ZnOTa2O5, Nb2O5, HfO2, TiO2 and In2O3 Do.

Further, it is preferable that the thickness of the phase correcting dielectric layer 80 is 60 nm to 90 nm.

In general, the dielectric constant of a dielectric generally decreases as the wavelength increases. This phenomenon has a negative effect on maintaining extinction interference in the entire wavelength range. As the wavelength changes, the refractive index changes less, that is, (N = 1), and thus, a dielectric material having a small refractive index is more suitable for a phase-correcting layer than a dielectric material having a large refractive index.

Next, the absorption / reflection metal layer 70 will be specifically described below.

The second metal layer 70 formed of the thin metal layer may be made of Cr, Ti, Mo, Co, Ni, W, Al, Ag, Au, Cu, Fe, Or an alloy of the above metals.

The thickness of the absorption / reflection metal layer 70 is preferably 6 nm to 15 nm, and more preferably 6 nm to 9 nm in the case of Cr. If the thickness of the absorptive / reflective metal layer 70 is less than 6 nm, there is a problem that external light absorbed by the absorptive / reflective metal layer is reduced, thereby increasing the reflectance of the external light. When the thickness exceeds 15 nm, the light emitted from the organic light- There is a problem that the light efficiency is lowered.

In a conventional top-emitting OLED device, the layer in which the reflection of the external light is most generated is reflected in the Mg: Ag layer of the upper electrode layer by 60% or more of the ambient light. Next, it is reflected from the bottom Ag layer and the remainder is reflected from each interface. Accordingly, by utilizing the phenomenon of optical extinction interference, which is already mentioned above, in the reflection of external light, and absorption of light by the second metal layer due to the property that some light is absorbed when the light transmits through the metal, The external light reflection can be further reduced.

That is, when an absorption / reflection metal layer is used, absorption of external light not completely canceled by extinction interference is absorbed by utilizing absorption phenomenon occurring when transmitting the absorption / reflection metal layer as well as utilizing extinction interference phenomenon with some reflected light Minimize reflection.

Accordingly, in the case of the absorptive / reflective metal layer 70, a metal having a large amount of absorption while satisfying extinction interference conditions is most suitable. When these metals are examined, a metal having a refractive index and an absorption coefficient of about 2 to 4 is suitable.

FIG. 6 is a graph showing absorptivity for a metal having a thickness of 10 nm. As shown in FIG. 6, Cr, Mo, Ti, Co, Ni, W Is appropriate. When such a metal is used, extinction interference effect due to reflection of the metal layer and high absorption rate can effectively absorb light in the entire visible light wavelength region, thereby reducing external light reflection.

In the present invention, a metal-dielectric thin film is actually formed by using a phase adjustment layer (phase adjustment dielectric layer) 60 of one layer, a first absorption metal layer (absorption / reflection metal layer) 70 and a phase correction layer Polarizer. If this is further expanded, it can sufficiently reduce the reflection of external light instead of the circular polarizer even when a plurality of metal-dielectric thin films are used. Therefore, in the present invention, it is possible to extend to a structure replacing the circular polarizer by using a plurality of metal-dielectric thin films. FIG. 8 shows the structure of an OLED structure using a metal-dielectric thin film composed of several layers.

Hereinafter, various embodiments of the anti-reflection organic light emitting diode device according to the present invention will be described.

[Example 1]

In the case of Embodiment 1, Cr is used as the absorption / reflection metal layer 70 and SiO 2 is used as the phase adjustment layer (phase adjustment dielectric layer 60) and the phase correction layer (phase correction dielectric layer 80). In the present invention, a transfer matrix method suitable for reflection and transmission calculation of a thin film structure is used. This transmission matrix approach is well documented in 'Macelod's' Thin-Film Optical Filter 3rd Edition' as it is already used in numerous optical coating and optical filter designs.

8A and 8B show the reflectance against external light according to the thickness variation of the phase adjustment layer (phase adjustment dielectric layer) 60 and the phase correction layer (phase correction dielectric layer) 80. FIG. 8A shows a change in the reflection of external light according to the thickness variation of the phase adjustment layer (phase adjustment dielectric layer 60). Here, the numbers in parentheses are luminous reflectance values, which are the smallest reflection values at 60 nm of SiO2. 8B shows the reflection value according to the thickness of the phase correction layer (phase correction dielectric layer) 80. FIG. FIG. 9A shows the external light reflection according to the thickness variation of Cr, and FIG. 9B shows the intensity according to the thickness variation of Cr, wherein the values in parentheses indicate the luminance ratio to the conventional OLED device having a polarizer . Therefore, an efficiency improvement of about 3% compared to the conventional OLED structure is achieved at Cr 6 nm thickness. In this structure, when the thickness of the phase correction layer (phase correction dielectric layer) 80 is 80 nm, the thickness of Cr is 6 nm, and the thickness of the phase adjustment layer (phase adjustment dielectric layer 60) is 60 nm, %, And the efficiency is improved by about 3% compared to the conventional OLED structure equipped with a polarizer. In all of the following embodiments, the thickness of the organic light emitting layer 40 and the first electrode (ITO, 30) were set to the same conditions as those of the conventional OLED structure. In addition, the thickness of the second electrode 50 was fixed to 18 nm, which is the same as that of the conventional OLED structure. However, in Examples 2 and 6, the tendency of the second electrode 50 according to the thickness variation was analyzed.

[Example 2]

In the second embodiment, when the absorption / reflection metal layer 70 is Cr and SiO 2 is used as the phase adjustment layer (phase adjustment dielectric layer) 60 and the phase correction layer (phase correction dielectric layer) 80, (50) were analyzed.

10A and 10B are graphs showing the external light reflectance and the efficiency according to the thickness variation of the second electrode 50. FIG. In Example 1, the thickness of the second electrode 50 was 18 nm, which is the same as that of the conventional OLED structure, wherein the external light reflection was about 2.9%, and the efficiency was improved by about 3% compared to the conventional OLED structure.

However, as the Mg: Ag thickness of the second electrode 50 is decreased, the efficiency is improved and the reflection of external light is increased. At about 16 nm, the external light reflection is improved by 3.7% and the efficiency is improved by about 26%.

Therefore, it was found that the efficiency of external light reflection can be controlled by controlling the Mg: Ag electrode in the range not affecting the electrical characteristics.

[Example 3]

In the case of Example 3, the absorption / reflection metal layer 70 was used as Cr, and the phase correction layer (phase correction dielectric layer) 80 and the phase adjustment layer (phase adjustment dielectric layer) 60 were used as SiNx.

11A and 11B are graphs showing the reflection of external light and the efficiency when the phase correction layer (phase correction dielectric layer) 80 is SiNx with a thickness of 60 nm and the thickness of Cr is 10 nm. Here, when the thickness of the phase adjustment layer (phase adjustment dielectric layer 60) is 50 nm, the external light reflection is about 4.8%, and the efficiency is improved by about 2%.

[Example 4]

In the case of Example 4, the absorption / reflection metal layer 70 was used as Ti, and the phase adjustment layer (phase adjustment dielectric layer 60) and the phase correction layer (phase correction dielectric layer 80) were used as SiO2.

12A and 12B show that when the thickness of the absorption / reflection metal layer 70 is 80 nm or less and the thickness of the absorption / reflection metal layer 70 is less than or equal to the thickness (Ti) of the phase adjustment layer Which is a graph showing the external light reflectance and intensity tendency.

When Ti is 10 nm thick, the external light reflection is about 4.2%, and the light efficiency is improved by about 28% compared to the conventional OLED structure equipped with the circular polarizer. In the case of Ti, since it is a metal having less absorption than Cr, it shows good results in terms of efficiency.

[Example 5]

In Example 5, the absorptive / reflective metal layer 70 was used as Ti, the SiNx was used as the phase adjustment layer (phase adjustment dielectric layer 60), and the SiO 2 was used as the phase correction layer (phase correction dielectric layer 80).

13A and 13B show that SiNx is used as the phase correction layer (phase correcting dielectric layer) 80 and has a thickness of 70 nm and SiNx is used as the phase adjusting layer (phase adjusting dielectric layer 60) At this time, the absorbing / reflecting metal layer 70 shows the tendency toward the efficiency of reflection of external light according to the change of the thickness of Ti. When Ti is 11 nm, the external light reflection is 4.1%, and the light efficiency is improved by about 42% compared to the regular OLED structure. That is, the case of Embodiment 5 shows the best performance.

[Example 6]

In the case of Example 6, when Ti is used for the absorption / reflection metal layer 70, and SiNx is used for the SiO 2 and the phase adjustment layer (phase adjustment dielectric layer, 60) as the phase correction layer (phase correction dielectric layer) The change in the thickness of the second electrode 50 which is the cathode (Mg: Ag) shows a good performance in the fifth embodiment. In this case, the change with the thickness of the second electrode 50 is examined. In general, the semi-transmissive film metal cathode has a great influence on the optical characteristics depending on the electrical characteristics, transmittance, and reflectance as an electron injection source of the OLED element. Therefore, the characteristics according to the change in the basic thickness have been grasped. Here, the thickness of Ti is 11 nm, the thickness of the phase adjustment layer (phase correcting dielectric layer, 80) is 70 nm and the thickness of the phase adjustment layer (phase adjustment dielectric layer, 60) is 50 nm .

FIG. 14A is a graph showing the external light reflectance according to the thickness of the second electrode 50, and FIG. 15B is a graph showing the efficiency according to the thickness of the second electrode 50. It can be seen that when the thickness of the second electrode (50) of Mg: Ag is 18 nm, the external light reflectance is 4.1% and the efficiency improvement is 42%.

As described above, the present invention is not limited to the embodiments and drawings disclosed in the present specification, and it is to be understood that within the technical scope of the present invention, It will be understood that various modifications may be made by those skilled in the art.

Claims (18)

An organic light emitting diode device, and an anti-reflection thin film formed on the organic light emitting diode device,
The organic light emitting diode device includes:
A glass substrate;
A rear metal layer formed on the glass substrate;
A first electrode formed on the rear metal layer;
An organic light emitting layer formed on the first electrode;
And a second electrode formed on the organic light emitting layer to face the first electrode,
Wherein the anti-reflective thin film is a metal-dielectric multilayer thin film,
The metal-dielectric multilayered thin film may include a metal-
A phase adjusting dielectric layer formed on the organic light emitting diode device;
An absorption / reflection metal layer formed on the phase-adjusting dielectric layer; And
And a phase correction dielectric layer formed on the absorption / reflection metal layer,
Wherein the phase adjustment dielectric layer is a dielectric layer that adjusts the relative phase between light reflected from the second electrode and light reflected from the absorption / reflection metal layer to be in a range of 120 to 240 degrees, and the material of the phase adjustment dielectric layer is SiOx ), SiNx (x? 1), MgF2, CaF2, Al2O3, SnO2, ITO, IZO, ZnO, Ta2O5, Nb2O5, HfO2, TiO2 and In2O3. .
delete The method according to claim 1,
The rear metal layer improves the electrical resistance of the first electrode and the rear metal layer is made of Ag, Al, Mg, Cr, Ti, Ni, W, Au, Ta, Cu, Co, Fe, And the metal is an alloy of any one of the metals selected from the group consisting of aluminum, aluminum, and the like.
The method according to claim 1,
Wherein the first electrode is a transparent conductive oxide (ITO, IZO) or a semi-transparent metal as a transparent anode.
The method according to claim 1,
The second electrode is formed as a semi-transparent metal layer and the second electrode is made of Ag, Al, Mg, Cr, Ti, Ni, W, Au, Ta, Cu, Co, Fe, And the metal is an alloy of any one of the metals selected from the group consisting of Al, Ti, and Al.
delete The method according to claim 1,
And the light of the external light reflected by the back metal layer and the second electrode is absorbed in the absorption / reflection metal layer or in the extinction interference with the light reflected from the absorption / reflection metal layer by the phase adjustment dielectric layer and the phase correction dielectric layer. An anti-reflection organic light emitting diode device.
The method according to claim 1,
The absorption / reflection metal layer is formed of a thin metal thin film, and the material of the absorption / reflection metal layer is selected from the group consisting of Cr, Ti, Mo, Co, Ni, W, Al, Ag, Au, Cu, Fe, Wherein the organic electroluminescent device is an electroluminescent organic electroluminescent device.
delete The method according to claim 1,
Wherein the phase adjustment dielectric layer is a dielectric layer that adjusts the relative phase between the light reflected from the second electrode and the light reflected from the absorption / reflection metal layer to be in a range of 150 to 210 degrees.
The method of claim 10,
Wherein the phase adjustment dielectric layer is a dielectric layer that adjusts the relative phase between the light reflected from the second electrode and the light reflected from the absorption / reflection metal layer to be 180 degrees.
The method according to claim 1,
Wherein the phase correction dielectric layer is a dielectric layer for correcting a relative phase controlled by the phase adjustment dielectric layer when the phase deviates from 180 degrees and the material of the phase correction dielectric layer is SiOx (x? 1), SiNx (x? 1) Wherein the second electrode is any one selected from the group consisting of CaF2, Al2O3, SnO2, ITO, IZO, ZnO, Ta2O5, Nb2O5, HfO2, TiO2 and In2O3.
The anti-reflection organic light emitting diode device according to claim 1, wherein the thickness of the phase adjusting dielectric layer is 30 nm to 80 nm.
The anti-reflection organic light emitting diode device according to claim 1, wherein the thickness of the absorption / reflection metal layer is 6 nm to 15 nm.
The anti-reflection organic light emitting diode device according to claim 1, wherein the phase correction dielectric layer has a thickness of 60 nm to 90 nm.
The anti-reflection organic light emitting diode device according to claim 1, wherein the metal-dielectric multilayer thin film is a plurality of two or more.
18. The method of claim 16,
Wherein light of the external light reflected by the rear metal layer and the second electrode is canceled by the metal-dielectric multilayer thin film or absorbed by the metal-dielectric multilayer thin film.
18. The method of claim 16,
Wherein the metal-dielectric multilayer thin film comprises a dielectric layer and a semi-transparent metal layer, and the material of the dielectric layer is selected from the group consisting of SiOx (x? 1), SiNx (x? 1), MgF2, CaF2, Al2O3, SnO2, ITO, IZO, ZnO, Ta2O5 , Nb2O5, HfO2, TiO2, and In2O3, and the material of the transflective metal layer is at least one selected from the group consisting of Cr, Ti, Mo, Co, Ni, W, Al, Ag, Au, Cu, Wherein the metal is an alloy of any one of the metals selected from the group consisting of aluminum, aluminum, and combinations thereof.

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