KR102065484B1 - Polarizing Plate and Organic light Emitting Display Device Using The Same - Google Patents

Abstract

Anti-reflective polarizing plate according to an embodiment of the present invention, the multifunctional polarizer protective film; A polarizer formed on the multifunctional polarizer protective film; And a protective film formed on the polarizer, wherein the multifunctional polarizer protective film is a film satisfying 0.8 <R1 / R2 <1.1, 0.9 <R3 / R2 <2. In this case, R1 is defined as a phase difference value at 450 nm wavelength, R2 is a phase difference value at 550 nm wavelength, and R3 is defined as a phase difference value at 650 nm wavelength. Accordingly, by introducing a reflective ring polarizing plate made of a multifunctional polarizer protective film it is possible to improve the problem of color degradation in the side viewing angle. In addition, through the multi-function polarizer protective film that can perform the role of the polarizer protective film and the retardation plate at the same time, it is possible to reduce the thickness of the polarizing plate, and to reduce the manufacturing cost and simplify the process.

Description

Polarizing Plate and Organic Light Emitting Display Device Using The Same

The present invention relates to a polarizing plate and an organic light emitting display device including the same, and more particularly to an organic light emitting display device using a polarizing plate for reflection ring.

One of the new flat panel display devices, the organic light emitting display device is a self-luminous type, and has a superior viewing angle and contrast ratio compared to LCD, and it is possible to be thin and light because no backlight is required. Is also advantageous. In addition, it is possible to drive a DC low voltage, has a fast response speed, in particular, there is an advantage in terms of manufacturing cost.

The organic light emitting diode includes an organic light emitting diode composed of an organic light emitting layer between an anode and a cathode. The organic light emitting diode combines the holes supplied from the anode and the electrons received from the cathode to form an exciton, which is a hole-electron pair, in the organic light emitting layer, and is generated when the excitons return to the ground state. It emits light by energy. Accordingly, the image is displayed in the organic light emitting display device using the generated light.

At this time, when the light is introduced from the outside, the introduced light is sequentially incident to the polarizing plate and the phase film, and then reflected again by the metal electrode of the organic light emitting diode. Due to the presence of light reflected back by the metal electrode constituting the organic light emitting diode, a problem such as glare occurs when a user looks at the organic light emitting display device.

For example, when an image of an organic light emitting display device is viewed in an environment where external light is present, such as sunlight, an image of which the contrast itself is degraded due to the light reflected from the device is eventually seen.

Accordingly, in order to improve the contrast of the organic light emitting display device, a compensation film of a circular polarizer is introduced. The circular polarizing plate is composed of a linear polarizing plate and a phase difference plate, and the phase difference plate has a broadband property, that is, a reverse dispersion characteristic (characteristic 1 of FIG. 4) in which the phase difference value is also increased when the wavelength is increased in order to reduce the reflectance change according to the wavelength. Or, it has a flat dispersion characteristic (characteristic 2 of FIG. 4) whose phase difference value is constant regardless of the wavelength.

However, in the conventional circular polarizer, only the characteristics when viewed from the front side are taken into consideration, resulting in a problem that the color is changed depending on the azimuth angle with the deterioration of the characteristics according to the viewing angle.

Therefore, in the use of the organic light emitting display device, various methods for solving the viewing angle and color problems by improving the problems caused by the external light inflow as described above are emerging.

Disclosure of Invention The present invention has been made in view of the above-described problems, and it is an object of the present invention to provide a polarizing plate and a organic light emitting display device including the same, in which color degradation according to a viewing angle does not occur while improving problems caused by external light inflow.

Another object of the present invention is to provide a polarizing plate capable of reducing manufacturing costs and simplifying processes, and an organic light emitting display device including the same.

Anti-reflective polarizing plate according to an aspect of the present invention for achieving the above object is a multifunctional polarizer protective film; A polarizer formed on the multifunctional polarizer protective film; And a protective film formed on the polarizer, wherein the multifunctional polarizer protective film is a film satisfying 0.8 <R1 / R2 <1.1, 0.9 <R3 / R2 <2. In this case, R1 is defined as a phase difference value at 450 nm wavelength, R2 is a phase difference value at 550 nm wavelength, and R3 is defined as a phase difference value at 650 nm wavelength.

According to the present invention, by introducing a reflection ring polarizing plate made of a multi-functional polarizer protective film can improve the problems of preventing glare due to the inflow of external light and lowering the contrast, in particular, the color does not decrease even in the viewing angle of the side Can be.

In addition, through the multi-function polarizer protective film that can perform the role of the polarizer protective film and the retardation plate at the same time, it is possible to reduce the overall thickness of the polarizing plate, and to reduce the manufacturing cost and simplify the process by applying to the organic light emitting display device do.

Accordingly, the organic light emitting display device having a high resolution can be thinned due to the above characteristics.

1 is a view schematically showing an anti-reflective polarizing plate according to an embodiment of the present invention;
2 and 3 schematically show a conventional polarizer;
4 is a diagram for comparing wavelength dispersion characteristics;
5 is a view comparing reflectivity according to azimuth angles of Example 1 and Comparative Example 1;
6 and 7 are views for showing the reflection color difference according to the viewing angles of Example 1 and Comparative Example 1;
8 is a view comparing reflectivity according to azimuth angles of Example 2 and Comparative Example 2; And
9 and 10 are diagrams for showing the reflection color difference according to the viewing angles of Example 2 and Comparative Example 2. FIG.

Hereinafter, exemplary embodiments will be described in detail with reference to the accompanying drawings. Like numbers refer to like elements throughout. In the following description, when it is determined that a detailed description of known contents or configurations related to the present invention may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

1 is a view schematically showing an anti-reflective polarizing plate 100 according to an embodiment of the present invention.

As shown in FIG. 1, the anti-reflective polarizing plate 100 includes a multifunctional polarizer protective film 110, a polarizer 120 formed on the multifunctional polarizer protective film 110, and a protective film formed on the polarizer 120. And 130.

Specifically, the multifunctional polarizer protective film may simultaneously perform the roles of the polarizer protective film and the retardation plate. In this case, the retardation plate corresponds to a positive biaxial positive B plate and may have a phase difference Ro corresponding to λ / 4.

Looking specifically, the multifunction polarizer protective film 110 has the following characteristics.

First, the multifunctional polarizer protective film 110 may adjust the refractive index in three dimensions. There is a correlation between the refractive indices in the x, y and z directions in three-dimensional space. In this case, when n _x is defined as a refractive index in the x direction, n _y is a refractive index in the y direction, and n _z is a refractive index in the z direction, the refractive index of the multifunctional polarizer protective film 110 is n _x > n _z > n _y . Have a relationship.

In particular, the multifunction polarizer protective film 110 may satisfy 0.3 <Nz <0.7 when Nz = (n _× −nz) / (n _× −n _y ), and more preferably, the Nz coefficient has 0.5. Compared with the conventional polarizing plate, the color is excellent according to the azimuth angle and the viewing angle according to the Nz coefficient. Since the refractive index value in the thickness direction exists, the change in color according to the azimuth and viewing angle is small.

In addition, the phase difference of the multi-function polarizer protective film 110 may satisfy 130 <Ro <150, and 45 <Rth <95 when 540 nm <λ <600 nm. In this case, if d is the thickness of the multi-functional polarizer protective film, n _x is the refractive index in the x direction, n _y is the refractive index in the y direction, n _z is the refractive index in the z direction, Ro = (n _x -n _{y which is an in-} plane phase difference ) d and Rth = (n _z -n _y ) d which is a phase difference in the thickness direction.

In the multifunction polarizer protective film 110, the direction in which the refractive index is greatest corresponds to the phase delay axis, and the phase delay axis exists in the plane of the multifunction polarizer protective film 110. Accordingly, an angle θ formed between the phase retardation axis of the multifunction polarizer protective film 110 and the transmission axis of the polarizer 120 may satisfy −50 <θ <50.

The polarizer 120 may include a polyvinyl alcohol (PVA) layer, and the protective film 130 may use a TAC film or an acrylate-based film, but the present invention The idea of is not limited to this.

2 and 3 are schematic views illustrating a conventional polarizing plate 200 as a comparative example. Here, the polarizing plate 200 of FIG. 2 and FIG. 3 has a structure in which a retardation film is formed of a single layer or multiple layers.

As shown in FIG. 2, the conventional polarizing plate 200 includes a retardation film 210 and a polarizer 220, and a polarizer protective film 230 is disposed above and below the polarizer 220. . At this time, unlike the polarizing plate of the present invention, the conventional polarizing plate 200 has a correlation of the refractive index n _x > n _y = n _z .

Accordingly, in the case of the conventional polarizing plate 200, the characteristics according to the viewing angle is bad, there is a problem that the color is periodically changed according to the azimuth angle. In addition, in the case of the multilayer structure, the phase axis of the retardation film 210 should be manufactured to be adjusted to be 15 degrees and 75 degrees with respect to the transmission axis of the polarizing plate, which makes the process complicated.

4 is a diagram for comparing wavelength dispersion characteristics.

As shown in FIG. 4, the multifunctional polarizer protective film 110 according to an embodiment of the present invention satisfies a reverse dispersion characteristic or a flat dispersion characteristic.

First, if the retardation value Ro corresponding to the reference wavelength is R (λ), the retardation value at 450 nm wavelength (R1) / the retardation value at 550 nm wavelength R2 and 650 nm The retardation value at a wavelength '(R3) /' the retardation value at a wavelength of 550 nm '(R2) has the following relationship.

0.8 <R1 / R2 <1.1

0.9 <R3 / R2 <2

Hereinafter, the characteristic evaluation results of the reflective ring polarizing plate 100 and the conventional polarizing plate 200 according to an embodiment of the present invention will be described in more detail.

Here, the following experimental results were obtained through the simulation, using the program of TechWiz 1D, the center wavelength when designing the retardation plate was set to 550nm as the reference wavelength.

Example  One

The heat shrink film was attached on both sides to a cyclo olefin based polymer film and stretched near the Tg temperature. At this time, uniaxial stretching or biaxial stretching can be performed. Subsequently, the heat shrink film was peeled off to prepare a multifunctional polarizer protective film (biaxial positive B plate). The film formed in this way is bonded to the polarizer using a water-based or UV-curable adhesive, the surface-treated TAC film or acrylate (acrylate) film is bonded to the top of the polarizer.

In this case, in Example 1, the wavelength dispersion characteristics of the + B plate are R1 / R2 and R3 / R2 representing almost 1, which means 'characteristic of flat dispersion', and the Nz coefficient is 0.5.

Comparative example  One

A film was obtained using the prepared birefringent film as a protective film of the polarizer, without using a heat shrink film while preparing under the same conditions as in Example 1.

Although Comparative Example 1 has the same wavelength dispersion characteristic as Example 1, the birefringence characteristic shows uniaxiality rather than biaxiality, so the Nz coefficient is close to one.

5 is a view comparing reflectivity according to azimuth angles of Example 1 and Comparative Example 1. FIG. Here, the viewing angle (polar angle) Theta is 60 degrees, that is, it is a figure evaluated by comparing the wavelength average reflectance according to the azimuth angle Phi from the side.

As shown in FIG. 5, Example 1 compared to Comparative Example 1 was able to confirm that the reflectance is lower at all azimuth angles.

6 and 7 are diagrams for illustrating the reflection color difference according to the viewing angles of Example 1 and Comparative Example 1. FIG.

As shown in FIG. 6, in Example 1, the color difference appeared regularly according to the azimuth angle, and the size of the color difference was also very small.

On the other hand, as shown in Figure 7, in Comparative Example 1, the color difference was irregular according to the azimuth angle, it was confirmed that the size of the color difference is larger than Example 1.

5 is a view comparing reflectivity according to azimuth angles of Example 1 and Comparative Example 1. FIG. Here, the viewing angle (polar angle) Theta is 60 degrees, that is, it is a figure evaluated by comparing the wavelength average reflectance according to the azimuth angle Phi from the side.

As shown in FIG. 5, Example 1 compared to Comparative Example 1 was able to confirm that the reflectance is lower at all azimuth angles.

6 and 7 are views for showing the reflection color difference according to the viewing angles of Example 1 and Comparative Example 1.

As shown in FIG. 6, in Example 1, the color difference appeared regularly according to the azimuth angle, and the size of the color difference was also very small.

On the other hand, as shown in FIG. 7, in Comparative Example 1, the color difference was irregular according to the azimuth angle, and the magnitude of the color difference was also larger than that of Example 1.

Example  2

A cellulose acetate film in which one of the hydroxy groups of cellulose was partially substituted with a carbamate group was drawn near the Tg temperature. In this case, a multifunctional polarizer protective film (biaxial positive B plate) was manufactured by uniaxial stretching or biaxial stretching. The film formed in this way is bonded to the polarizer using a water-based or UV-curable adhesive, the surface-treated TAC film or acrylate (acrylate) film is bonded to the top of the polarizer.

In this case, the wavelength dispersion characteristic of the + B plate represents the 'inverse wavelength dispersion characteristic' of R1 / R2 <1, R3 / R2> 1, and the Nz coefficient is 0.5.

Comparative example  2

The amount of the substituent was adjusted while preparing under the same conditions as in Example 2 to obtain a film using the prepared birefringent film as a protective film of the polarizer.

Comparative Example 2 has the same wavelength dispersion characteristic as Example 2, but since the birefringence characteristic shows uniaxiality rather than biaxiality, the Nz coefficient is almost equal to one.

8 is a view comparing reflectivity according to azimuth angles of Example 2 and Comparative Example 2. FIG.

Viewing angle (polar angle) Theta is 60 degrees, that is, the figure which evaluates by comparing the wavelength average reflectance according to the azimuth angle Phi from the side.

As shown in FIG. 8, Example 2 compared to Comparative Example 2 was confirmed that the reflectance is lower at all azimuth angles.

9 and 10 are diagrams for illustrating the reflection color difference according to the viewing angles of Example 2 and Comparative Example 2. FIG.

As shown in FIG. 9, in Example 2, the color difference appeared regularly according to the azimuth angle, and it was confirmed that the size of the color difference was also very small.

On the other hand, as shown in FIG. 10, in Comparative Example 2, the color difference appeared irregularly according to the azimuth angle, and the magnitude of the color difference was also larger than that of Example 2.

Therefore, according to the present invention, it is possible to improve the viewing angle problem in the side according to the external light. That is, the contrast may have an effect of not lowering the contrast, and the problem of changing the color depending on the viewing direction may be improved.

In addition, according to the present invention, through the multi-function polarizer protective film that can perform the role of the polarizer protective film and the retardation plate at the same time, it is possible to reduce the overall thickness of the polarizing plate, to reduce the manufacturing cost and simplify the process.

Hereinafter, the internal structure of the organic light emitting display device according to the exemplary embodiment having the configuration of the antireflective polarizing plate 100 will be described.

Although not shown in the drawings, the organic light emitting display device includes an OLED panel in which a driving and switching thin film transistor, a first substrate on which an organic light emitting diode is formed, and a second substrate spaced apart from each other are sealed with edges sealed through a failure turn. It includes, and the anti-reflective polarizing plate is attached to the back surface of the first substrate in the light transmission direction of the OLED panel. That is, by attaching the anti-reflective polarizing plate according to the present invention, it is possible to block the external light to improve the contrast, it is possible to prevent the color deterioration from the side.

First, a gate wiring and a data wiring defining each pixel region P1, P2, and P3 by crossing each other are disposed on the first substrate, and a power wiring extending in parallel with any one of them. Each of P2 and P3 has a switching thin film transistor connected to a gate line and a data line, and a driving thin film transistor connected to the switching thin film transistor. Here, the driving thin film transistor is connected to the anode.

The organic light emitting diode includes an organic layer between an anode and a cathode facing the organic layer, and the organic layer includes a light emitting layer including a hole injection layer, a hole transporting layer, a first light emitting layer, a second light emitting layer, and a third light emitting layer, and an electron transporting layer. The first emission layer may be formed of a red organic material, the second emission layer may be formed of a green organic material, and the third emission layer may be formed of a blue organic material.

Here, the anode is formed in one plate shape on the red, green, and blue pixel regions P1, P2, and P3 on the first substrate. The anode is a reflective electrode, for example, a transparent conductive material layer having a high work function such as indium-tin-oxide (ITO) and reflection such as silver (Ag) or silver alloy (Ag alloy) It may be a multilayer structure including a material layer.

A hole injection layer and a hole transport layer are formed on the anode at positions corresponding to all of the pixel regions P1, P2, and P3. The hole transport layer may be referred to as a common layer, and the hole injection layer may be omitted. The hole injection layer and the hole transport layer may have a thickness of about 100 to about 600 mm, but may be adjusted in consideration of hole injection characteristics and hole transport characteristics.

The hole transport layer not only transports holes easily to the light emitting layer but also serves to increase luminous efficiency by suppressing movement of electrons generated from the cathode to the light emitting region. That is, the hole transport layer serves to facilitate the transport of holes, NPD (N, N-dinaphthyl-N, N'-diphenyl benzidine), TPD (N, N'-bis- (3-methylphenyl) -N, N'-bis- (phenyl) -benzidine), TCTA (4- (9H-carbazol-9-yl) -N, N-bis [4- (9H-carbazol-9-yl) phenyl] -benzenamine), CBP (4,4'-N, N'-dicarbazole-biphenyl), s-TAD or MTDATA (4,4 ', 4 "-Tris (N-3-methylphenyl-N-phenyl-amino) -triphenylamine) However, the spirit of the present invention is not limited thereto.

In the light emitting layer, a first light emitting layer, a second light emitting layer, and a third light emitting layer are formed at positions corresponding to the first to third pixel areas P1, P2, and P3. That is, a first emission layer is formed at a position corresponding to the first pixel region P1, a second emission layer is formed at a position corresponding to the second pixel region P2, and corresponds to a third pixel region P3. In the position, a third light emitting layer is formed. The thickness of the first light emitting layer, the second light emitting layer, and the third light emitting layer may be about 100 to about 400 mm, but may be adjusted in consideration of light emission characteristics.

The emission layer may be formed of a host and a dopant, and may include a material emitting red, green, blue, or white light, and may be formed using phosphorescent or fluorescent materials.

Here, when the light emitting layer emits red, it includes a host material containing CBP (carbazole biphenyl) or mCP (1,3-bis (carbazol-9-yl), PIQIr (acac) (bis (1-phenylisoquinoline) Phosphorescent material comprising a dopant containing at least one selected from acetylacetonate iridium, PQIr (acac) (bis (1-phenylquinoline) acetylacetonate iridium), PQIr (tris (1-phenylquinoline) iridium) and PtOEP (octaethylporphyrin platinum) Alternatively, it may alternatively be a fluorescent material including PBD: Eu (DBM) ₃ (Phen) or perylene, but is not limited thereto.

When the light emitting layer emits green, it may include a host material including CBP or mCP, and may be a phosphor including a dopant material including Ir (ppy) ₃ (fac tris (2-phenylpyridine) iridium). Alternatively, the fluorescent material may include Alq3 (tris (8-hydroxyquinolino) aluminum), but is not limited thereto.

When the light emitting layer emits blue, it may be a phosphor including a host material including CBP or mCP and including a dopant material including (4,6-F ₂ ppy) ₂ Irpic or L2BD111.

Alternatively, it may be a fluorescent material including any one selected from spiro-DPVBi, spiro-6P, distilbenzene (DSB), distriarylene (DSA), PFO-based polymer and PPV-based polymer, but is not limited thereto. .

The electron transport layer is formed on the emission layer at a position corresponding to all of the pixel areas P1, P2, and P3, and thus may be referred to as a common layer. The electron transport layer may have a thickness of about 250 to 350 mm, but may be adjusted in consideration of electron transport characteristics. The electron transport layer may serve as an electron transport and injection layer, but an electron injection layer may be formed on the electron transport layer separately.

The electron transport layer may include any one or more selected from Alq3 (tris (8-hydroxyquinolino) aluminum), PBD, TAZ, spiro-PBD, BAlq and SAlq, but the spirit of the present invention is not limited thereto. In addition, the electron transport layer may be formed using an evaporation method or a spin coating method.

A cathode is formed on the electron transport layer. For example, the cathode is made of an alloy of magnesium and silver (Mg: Ag) to have a semi-transmissive property. That is, the light emitted from the light emitting layer is displayed to the outside through the cathode. Since the cathode has a transflective property, some of the light is directed toward the anode.

Accordingly, repetitive reflection occurs between the anode serving as the reflective electrode and the cathode, which is called a microcavity effect. That is, light is repeatedly reflected in the cavity between the anode, which is the anode, and the cathode, which increases the light efficiency.

Those skilled in the art to which the present invention pertains will understand that the above-described present invention can be implemented in other specific forms without changing the technical spirit or essential features.

Therefore, it is to be understood that the embodiments described above are exemplary in all respects and not restrictive. The scope of the present invention is shown by the following claims rather than the above description, and all changes or modifications derived from the meaning and scope of the claims and their equivalent concepts should be construed as being included in the scope of the present invention. do.

100: anti-reflective polarizing plate 110: multi-function polarizer protective film
120: polarizer 130: protective film
200: conventional polarizing plate 210: retardation film
220: polarizer 230: protective film

Claims (8)

A first substrate;
An organic light emitting diode on the first substrate and including an anode, a cathode, and an organic layer between the anode and the cathode;
A second substrate on the organic light emitting diode and bonded to the first substrate; And
And a reflective ring polarizing plate attached to a rear surface of the first substrate in a transmission direction of light to block external light.
The anode and the cathode are a reflective electrode and a semi-transmissive electrode, respectively
The anti-reflective polarizing plate
Multifunctional polarizer protective film;
A polarizer formed on the multifunctional polarizer protective film; And
It includes; a protective film formed on the polarizer;
The multifunction polarizer protective film satisfies 1.0 <R1 / R2 <1.1, 0.9 <R3 / R2 <1.0,
The refractive index of the multifunctional polarizer protective film, when Nz = (n _x- n _z ) / (n _x- n _y ) is characterized in that it satisfies 0.3 <Nz <0.7,
In this case, R1 is a phase difference value at 450 nm wavelength, R2 is a phase difference value at 550 nm wavelength, R3 is a phase difference value at 650 nm wavelength, n _x is a refractive index in the x direction, n _y is a refractive index in the y direction , n _z is a refractive index in the z direction, and n _x > n _z > n _y . delete The method of claim 1,
The phase difference of the multi-function polarizer protective film, when 540 nm <λ <600 nm, 130nm <Ro <150nm, and 45nm <Rth <95nm, characterized in that
Ro = (n _x -n _y ) d, Rth = (n _z -n _y ) d, d is the thickness of the multifunctional polarizer protective film, n _x is the refractive index in the x direction, n _y is the refractive index in the y direction, n _z Is an index of refraction in the z direction and is defined by n _x > n _z > n _y . The method of claim 1,
The multifunctional polarizer protective film,
An organic light emitting display device comprising a positive biaxial retardation layer. The method of claim 1,
The polarizer,
An organic light emitting display device, characterized in that polyvinyl alcohol (PVA). The method of claim 1,
And an angle? Between the phase retardation axis of the multifunction polarizer protective film and the transmission axis of the polarizer satisfies −50 <θ <50. delete delete

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