KR20130037601A - Oled display inculding polarizer - Google Patents

Abstract

PURPOSE: An OLED display device including a polarizer is provided to improve brightness and an external light reflection prevention function by attaching a circular polarizer having high luminance and polarization to a display surface. CONSTITUTION: A thin film transistor(34) for operating a pixel is formed on a first substrate(20). An anode electrode(36) is formed on the thin film transistor. An organic light emitting layer(38) is formed on the anode electrode. A cathode electrode(40) is formed on the organic light emitting layer. A protection unit(42) including a protection layer(72) and a shield cap(74) is formed on the cathode electrode. A second substrate(80) is arranged on the protection unit.

Description

Organic electroluminescent device display including polarizing plate {OLED DISPLAY INCULDING POLARIZER}

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a polarizing plate, and more particularly, to an organic light emitting display including a polarizing plate in view of poor visibility due to external light reflection of a display using an organic light emitting display.

Recently, flat panel displays are attracting attention such as liquid crystal displays, field emission displays, plasma display panels, and electroluminescent displays (“EL”). Display element). In particular, the electroluminescent device is basically formed by attaching electrodes to both sides of an organic light emitting layer including a hole transporting layer, a light emitting layer, and an electron transporting layer, and is attracting attention as a next-generation flat panel display due to features such as wide viewing angle, high opening ratio, and high color.

The EL device is largely divided into an inorganic EL device and an organic EL device according to a material used. Dual organic light emitting device emits light when electrons and holes are paired and extinguished when electrons are injected into the organic EL layer formed between the hole injection electrode and the electron injection electrode. There is an advantage.

In addition, the organic light emitting device can be formed on a flexible transparent substrate such as plastic, and can be driven at a voltage lower than 10V or lower than that of a PDP or an inorganic light emitting device, and consumes power. Is relatively small, and the color is excellent.

A display using the organic light emitting diode according to the related art having such characteristics will be described with reference to FIG. 1 as follows.

1 is a cross-sectional view of an example of a conventional organic light emitting display.

As shown in the drawing, the conventional organic light emitting diode display 1 is bonded to the first substrate 2 on which the organic light emitting layer 4 is formed, and the first substrate 2 and the sealant to protect the organic light emitting layer 4. And a second substrate 8 for the purpose.

The organic light emitting diode display 1 having such a structure is further provided with a polarizing plate 9 for blocking external light on the light emitting surface side at which the image is visually recognized, and when the display of FIG. The polarizing plate 9 is disposed on the outer surface of the substrate 8.

The polarizing plate 9 is composed of a λ / 4 retardation layer 9a and a linear polarization layer 9b. In the conventional organic light emitting diode display 1, the image quality of the display is reduced due to external light reflection characteristics when driven in an external environment. The polarizing plate 9 is attached to the outside of the display surface in order to prevent this from falling rapidly.

In the polarizing plate 9, light emitted from the organic light emitting layer 4 is incident on the display 1 and linearly polarized through the linear polarization layer 9b, and is circularly polarized through the λ / 4 retardation layer 9a and the second substrate. (8) As the left circularly polarized light and linearly polarized light are reflected by the reflecting plate (not shown) further provided thereto, the polarization direction is changed to reflect the reflected light to the λ / 4 retardation layer 9a and the linear polarization layer 9b. It cannot pass through the configured polarizing plate 9.

Therefore, the conventional organic light emitting display 1 has a polarizing plate 9 composed of a λ / 4 delay layer 9a and a linear polarization layer 9b on the outer surface of the first substrate 2 or the second substrate 8. By attaching to block the light from the outside to improve the contrast characteristics.

However, such an organic light emitting diode display improves the above-mentioned external light characteristics by applying a high brightness polarizing plate, but the polarization and light transmittance of light are inversely related to each other, and thus the characteristics thereof are limited. There is a problem.

The present invention has been made to solve the above problems, to provide an organic light emitting display device including a polarizing plate having a high group transmittance characteristics while maximizing the polarization degree of the polarizing plate attached to increase the visibility of the external light of the display The purpose is.

In order to achieve the above object, an organic light emitting display device according to a preferred embodiment of the present invention, the first substrate; A display element formed on the first substrate; A second substrate formed on the display element; And an iodinated ion concentration ratio attached to at least one of the first and second substrates, having a single transmission of 43% or more, a polarization efficiency of 99.99% or less, and adsorbed on a base film. I ₃ ^-: I ₅ ^-) is at least three iodide ion (I ₃ ^- comprises a polarizing plate formed to have a greater density ^than)) 5 and an iodine ion (I _5.

The polarizing plate is characterized by being produced by stretching the polyvinyl alcohol (PVA) film.

The polarizing plate may include a λ / 4 retardation layer formed on any one of the first substrate and the second substrate; And a linear polarization layer formed on the λ / 4 retardation layer.

The polarizing plate is characterized in that the polarization degree is 99.95% to 91.09% when the single transmittance is 44.1% to 47.8%.

When the external light is 0 lx (illuminance), the polarizing plate has a black gray level (0 gray) of 0.01530 cd / m ² to 0.01775 cd / m ² , and a white gray level (255 gray) of 284 cd / m ² to 312 cd / It is characterized by m ² .

The polarizing plate is characterized in that triacetyl cellulose (TAC) is further formed on the surface.

The polarizing plate has a reflectance of 5.409% to 10.708, a brightness of 28.3345 to 38.974, a first reflection color of -1.3728 to -5.3573, and a second reflection color of -6.8152 to -13.2553.

The display device may include a thin film transistor and an anode electrode sequentially formed on the first substrate; An organic light emitting layer formed on the anode electrode; A cathode electrode formed on the organic light emitting layer; And a protective film formed on the cathode electrode.

According to a preferred embodiment of the present invention, by attaching a circularly polarizing plate having high brightness and high polarization characteristics to the display surface of the organic light emitting display device, it is possible to maximize the brightness enhancement as well as preventing external light reflection.

1 is a cross-sectional view of an example of a conventional organic light emitting display.
2 is a cross-sectional view of an organic light emitting diode display including a polarizing plate of the present invention.

Hereinafter, an organic light emitting display device including a polarizing plate according to a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

2 is a cross-sectional view of an organic light emitting diode display including a polarizing plate of the present invention.

2, in the organic light emitting diode display 10 according to the exemplary embodiment, a thin film transistor 34 for driving a pixel is formed on the first substrate 20, and the thin film transistor 34 is formed. The anode electrode 36 is formed on (), and the organic light emitting layer 38 is formed on the anode electrode 36.

The cathode electrode 40 is formed on the organic light emitting layer 38, and the protective film 42 is formed on the cathode electrode 40.

In detail, the semiconductor layer 44 is formed on the first substrate 20, and the gate insulating film 50 and the gate electrode 52 are sequentially deposited and patterned thereon. In the thin film transistor unit 34 on the substrate 20, the semiconductor layer 44, the source and drain regions 48 of the thin film transistor 34, and electrode lines 56 through contact holes are formed.

A first interlayer insulating film 54, a planarization film 58, and an anode electrode 36 are sequentially formed on the gate electrode 52, and an anode electrode is formed between the gate insulating film 50 and the first interlayer insulating film 54. An electrode line 56 connecting the 36 and the source and drain regions 48 of the thin film transistor is formed.

A second interlayer insulating film 60 is formed on the anode electrode 36 to cover a portion between the anode electrodes 36, and the hole injection portion, the hole transfer portion, the R, G, B light emitting portion, and the electron transfer portion thereon. The organic light emitting layer 38 in which the electron injecting portion is sequentially deposited is formed.

In addition, the cathode electrode 40 is formed on the organic light emitting layer 38, and the protective part 42 formed in close contact with the cathode electrode 40 includes a protective film 72 and a shield cap 74.

Although not shown, the side surface portion of the organic light emitting diode 10 is formed to be in close contact with the upper surface portion by the protective film 72 and the shield cap 74 which are adhesives. The shield cap 74 may be formed of an encapsulant for molding the lower structure, or may be omitted by replacing the glass substrate and the second substrate 80 made of a material so as to face the upper substrate 20.

The polarizer 90 is disposed on the second substrate 80 without loss incident from the second substrate 80, and absorbs light incident from the outside to further increase the visibility of the image. The polarizing plate 90 is attached to the light emitting surface of the organic light emitting diode display 10, and when the light emitting surface of the organic light emitting diode display 10 is a rear surface, the polarizing plate 90 may be attached to the lower side of the first substrate 20. have.

The polarizing plate 90 is a polyvinyl alcohol (PVA) -based resin film by dyeing and uniaxial stretching by adsorption of a dichroic dye, λ / 4 retardation layer 92 in which the dichroic dye is oriented, and a linear polarizing layer ( 94), and may also be configured in a form in which a cellulose acetate-based polarization protective film (not shown) is stacked on one or both surfaces thereof. Here, it is preferable that a protective film is triacetyl cellulose (TAC).

In addition, an anthraquinone, an azo dye, or iodine may be used as the dichroic dye. In particular, in the case of iodine, a method of preparing a polarizer may be dyed in an aqueous solution of iodine while uniaxially stretching a polyvinyl alcohol (PVA) film substrate, It is manufactured through a process of drying or washing with water through a color correction process using potassium iodine or the like.

In particular, the polarizing plate 90 of the present invention is attached to any one surface corresponding to the light emitting surface of the first and second substrates constituting the organic light emitting display. In addition, iodine, which is a base film that is dyed on a polyvinyl alcohol film and forms a linear polarization layer 94, is iodine consisting of three iodide ions (I ₃ ⁻ ) and five iodide ions (I ₅ ⁻ ) in an ionic state. ).

Here, the ions of the above-mentioned iodine concentration ratio _{^{(I 3 -: I 5 -}} ) is at least three-iodide ion (I ₃ ^-) 5 iodide ions (I ₅ ^-) consists of a large concentration than, whereby the polarizing plate has high substance transmittance And polarization degree characteristics.

This characteristic is due to the change in the light characteristics absorbed by the iodine material according to the concentration ratio of each iodide ion. As the triiodide ion (I ₃ ⁻ ) is increased, the transmission becomes higher, and the iodide ion (I ₅ ⁻ ) is increased. It is a result of the characteristic that polarization degree becomes low, as () decreases.

Accordingly, the polarizing plate applied to the organic light emitting device display of the present invention, three-iodide ion (I ₃ ^-) 5 iodide ions (I ₅ ^-) than is produced so as to have a greater density ^{_{(I 3 -> I 5 -}} ), It has a characteristic of having a single transmission of 44.1% or more and a polarization efficiency of 99.95% or less.

According to this feature, the iodide ions are three-iodide ion of polarizer (I ₃ ^-) 5 iodide ions (I ₅ ^-) was prepared to three of the polarizer a different concentration ratios in the range having a larger concentration than that, this organic electroluminescent The results of the evaluation of the characteristics of each display attached to the device panel are as follows.

First, white gradation, black gradation, and outdoor contrast ratio (ACR) evaluation result data of illuminance (lx) by external light are summarized in Table 1 below. In Table 1, the unit of the luminance value according to each embodiment is cd / m ² .

Luminance (lx) 0 200 1000 2000 10000 20000 30000 Example 1 WHITE 281.4 285.3 297.7 313.1 436.1 590.0 743.1 BLACK 0.016 3.073 15.28 30.73 154.1 309.0 464.0 ACR 17590 92.8 19.5 10.2 2.83 1.91 1.60 Example 2 WHITE 296.7 301.2 314.6 331.7 468.3 639.1 810.5 BLACK 0.017 3.402 16.96 33.98 171.0 341.9 514.7 ACR 17450 88.5 18.5 9.76 2.74 1.87 1.57 Example 3 WHITE 309.8 315.5 332.4 354.3 525.1 740.6 955.6 BLACK 0.017 4.305 21.32 42.63 214.1 430.3 644.3 ACR 18220 73.3 15.6 8.31 2.45 1.72 1.48

In addition, for an organic light emitting diode display with a polarizing plate, the minimum gray scale (0 gray) and the maximum gray scale (255 gray) in the dark room (0 lx) and the fluorescent lamp (200 lx) are the luminance and the corresponding contrast ratio (CR). ) The results of the evaluation are summarized in Table 2 below.

darkroom Bright room (fluorescent light) Black White CR Black White CR Example 1 0.01530 284 18562 0.23214 285 1227 Example 2 0.01580 299 18924 0.36340 299 823 Example 3 0.01775 312 17577 0.46133 312 676

As shown in Table 2, the organic electroluminescent device display of the present invention has a black gray level (0 gray) of 0.01530 cd / m ² to 0.01775 cd / m ² when the external light is 0 lx (illuminance), and a white gray scale ( 255 gray) is 284 cd / m ² to 312 cd / m ² .

Here, it can be seen that the white gradation has a brightness increase effect of 5 to 10% in the dark room according to the concentration ratio, and the brightness of the black gradation increases in the bright room as the degree of polarization decreases, so that the contrast characteristic is lowered. Accordingly, the concentration ratio of the iodide ion _{^{(I 3 -: I 5 -}} ) (- >> I 5 - I 3) 5 O to which iodide ions are formed from a too low level with respect to the undesirable.

In addition, the evaluation result data on the light reflection characteristics of the organic light emitting display device with each polarizing plate having a different concentration ratio is summarized in Table 3 below.

Group Transmittance / Polarization (%) Reflectance Y (%) brightness Reflective color a Reflective Color b Example 1 44.1% / 99.95% 5.409 28.3345 -1.3725 -6.8152 Example 2 45.9% / 97.36% 6.799 31.549 -2.9427 -10.6545 Example 3 47.8% / 91.09% 10.708 38.974 -5.3573 -13.2553

As shown in Table 3, the organic light emitting display device of the present invention has a reflectance of 5.409% to 10.708, a brightness of 28.3345 to 38.974, a first reflection color of -1.3728 to -5.3573, and a second reflection color of -6.8152. Has a value from -13.2553.

In particular, it can be seen that the reflectance increases under the condition of polarization of 91.09%. Under these conditions, the brightness is increased, and the image tends to be bluish, so that at least the circular polarizer is formed to have a characteristic greater than 91.09%.

Accordingly, the organic light emitting display device including the polarizing plate according to the embodiment of the present invention improves visibility to external light by using a polarizing plate having a high single transmittance characteristic while maximizing polarization degree on the light emitting surface.

In addition, although not shown, in the case of a bottom emission type organic light emitting diode display having separate R, G, B, and W color filters applied to a large TV, the light is emitted toward the rear instead of the front as shown in FIG. Is emitted, and therefore the polarizing plate of the present invention should be attached to the back of the display, that is, the outer surface of the lower substrate.

In addition, in the case of a flexible type display capable of bending, a polarizing plate according to an embodiment of the present invention is attached to a plurality of polymer layers on a display element and an anti-scratch film on top thereof. The same effect as in one embodiment can be obtained.

Although the technical spirit of the present invention has been described in detail according to the above-described preferred embodiment, it should be noted that the above-described embodiment is for the purpose of description and not of limitation. In addition, those skilled in the art will understand that various embodiments are possible within the scope of the technical idea of the present invention.

10 organic light emitting diode display 20 first substrate
34: thin film transistor 36: anode electrode
38: organic light emitting layer 40: cathode electrode
42: protective film 44: semiconductor layer
48 source and drain regions 50 gate insulating film
52 gate electrode 54 first interlayer insulating film
56 electrode line 58 planarization film
60: second interlayer insulating film 72: protective film
74: shield cap 80: second substrate
90 polarizing plate 92 lambda / 4 delay layer
94: linear polarization layer

Claims (8)

A first substrate;
A display element formed on the first substrate;
A second substrate formed on the display element; And
An iodinated ion concentration ratio (I ₃ ) attached to at least one of the first and second substrates, having a single transmission of 43% or more, a polarization efficiency of 99.99% or less, and adsorbed on a base film ^-: I ^{_5-polarizing} plate formed to have a greater density than) ^-) is at least three-iodide ion (I ₃ ^-) 5 and an iodine ion (I ₅
An organic light emitting display device comprising a. The method of claim 1,
The polarizing plate includes:
An organic electroluminescent device display, which is prepared by stretching an polyvinyl alcohol (PVA) film. The method of claim 1,
The polarizing plate includes:
A λ / 4 retardation layer formed on any one of the first substrate and the second substrate; And
Linear polarization layer formed on the λ / 4 delay layer
An organic light emitting display device comprising a. The method of claim 3, wherein
The polarizing plate includes:
An organic light emitting display device, characterized in that the polarization degree is 99.95% to 91.09% when the unit transmittance is 44.1% to 47.8%. The method of claim 1,
The polarizing plate includes:
When the external light is 0 lx (illuminance), the black gray level (0 gray) is 0.01530 cd / m ² to 0.01775 cd / m ² , and the white gray level (255 gray) is 284 cd / m ² to 312 cd / m ² . An organic light emitting display device. The method of claim 1,
The polarizing plate includes:
An organic light emitting display device, characterized in that triacetyl cellulose (TAC) is further formed on the surface. The method of claim 1,
The polarizing plate includes:
An organic light emitting display having a reflectance of 5.409% to 10.708, a brightness of 28.3345 to 38.974, a first reflecting color of -1.3728 to -5.3573, and a second reflecting color of -6.8152 to -13.2553. The method of claim 1,
The display element,
A thin film transistor and an anode electrode sequentially formed on the first substrate;
An organic light emitting layer formed on the anode electrode;
A cathode electrode formed on the organic light emitting layer; And
A protective film formed on the cathode electrode
An organic light emitting display device comprising a.

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