KR100645716B1 - Organic light emitting display - Google Patents

Abstract

An organic light emitting display device is provided to obtain a uniform external radiation by guiding emitted light through a condensing material and a moisture-absorbing material, which have similar optical properties. An organic EL(Electro-Luminescence) layer(22) is laminated on one surface of a substrate(21). A sealing cover(23) is contacted on an outer periphery of one end of the substrate and forms a sealed space with the substrate. The organic EL layer is contained in the sealed space. A sealing agent(25) is configured between the sealing cover and the substrate, such that a sealing property between the sealing cover and the substrate is increased. A moisture-absorbing material(24) is attached to the inner surface of the sealing cover inside the sealed space. A condensing material(27) is condensed between the moisture-absorbing material and the organic EL layer and inside the sealed space. An optical property of the condensing material is different from that of the moisture-absorbing material by less than 10%.

Description

Organic light emitting display

1 is a cross-sectional view of a conventional organic light emitting display device;

2 is a photographic view showing the surface state of the PNPL formed on the encapsulation cover,

3 is a photographic view showing an enlarged projection portion of the PNPL with an electron microscope,

Figure 4a is a photographic view showing an enlarged cross-sectional view of part a of Figure 3,

Figure 4b is a photographic view showing an enlarged cross-sectional view of the portion b of Figure 3,

5 is a cross-sectional view of an organic light emitting diode display in which a PNPL surface is unevenly formed;

6 is a cross-sectional view of an organic light emitting diode display according to an exemplary embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

10, 20 ... organic light emitting display, 11, 21 ... substrate,

12, 22 ... organic electroluminescent part, 13, 23 ... bag cover,

14, 24 ... absorbent material, 15, 25 ... sealant,

27 ... filling, P ... turning

The present invention relates to an organic light emitting diode display, and more particularly, when a moisture absorbent is formed in an organic light emitting diode display of a top emission type, quality deterioration caused by distortion or intensity reduction of light emitted by a non-uniform surface thereof and The present invention relates to an organic light emitting display device in which a failure rate is reduced.

In general, an organic light emitting display device is a self-luminous display that emits light by electrically exciting an organic compound having phosphorescence or fluorescent light. The organic light emitting display device can be driven at a low voltage, is easy to thin, and has a wide viewing angle and a fast response speed. It is attracting attention as a next-generation display that can solve the problems that are pointed out as a problem in the device.

In the organic light emitting diode display, as the anode and cathode voltages are applied to the electrodes, holes injected from the electrode to which the anode voltage is applied move to the light emitting layer of the organic layer through the hole transport layer, and electrons are applied to the cathode voltage. It is injected from the electrode into the light emitting layer via the electron transport layer. Electrons and holes recombine in the light emitting layer to generate excitons, and the excitons transition from the excited state to the ground state, thereby emitting the light emitting layer to form an image.

1 illustrates an example of an organic light emitting display.

Referring to FIG. 1, in the organic light emitting diode display 10, a moisture absorbent 14 for absorbing moisture is disposed on the stack 12 of the substrate 11 and disposed on an inner side surface of the encapsulation cover 13. It is installed. As described above, the moisture absorbent 14 may be installed in the inner space formed between the encapsulation cover 13 and the substrate 11 to absorb moisture in the inner space, thereby preventing damage to the laminate 12 due to moisture. It is composed.

In the organic light emitting display as described above, a transparent moisture absorbent is used as the moisture absorbent 14. PNPL (Polymer Nano Porous Layer, PNPL ') is used as the transparent moisture absorbent. The PNPL is not formed flat in the formation process, and protrusions and end thickness differences are caused.

FIG. 2 is a photographic view showing the surface state of the PNPL formed on the encapsulation cover, and FIG. 3 is a photographic view showing an enlarged projection portion of the PNPL with an electron microscope. The same members as shown in FIG. 1 are shown with the same reference numerals.

In the process of fabricating the organic light emitting diode display, the PNPL 14 is injected and manufactured on the encapsulation cover 13. PNPL 14, which is a polymer material, is sufficiently filled laterally on the encapsulation cover 13 due to its viscoelasticity, but some surfaces may have protrusions as shown in the accompanying drawings, resulting in inferior surface uniformity.

4A is an enlarged photographic view of an inclined cross section of part a of FIG. 3, and FIG. 4B is an enlarged photographic view of an inclined cross section of part b of FIG. 3.

Referring to FIG. 4A, the surface of the PNPL 13 ideally filled on the encapsulation cover 14 is formed to be parallel to the encapsulation cover 14 surface to emit light from the stack 12 of the substrate 11. Light passes evenly. However, as shown in FIG. 4B, when the organic light emitting diode display 10 is driven, light emitted from the stack 12 of the substrate 11 may be distorted or the intensity of light may be reduced. . Therefore, the resulting degradation and increase in defective rate have been a problem.

SUMMARY OF THE INVENTION The present invention has been made to solve the conventional problems as described above, and an object of the present invention is to provide an organic light emitting display device which enables uniform transmission of emitted light by inserting a material having an optical property similar to that of a hygroscopic material. There is this.

In order to achieve the above object, the organic light emitting display device according to the present invention, a substrate; An organic electroluminescent unit stacked on one surface of the substrate; An encapsulation cover contacting the outer periphery of the end of the substrate to accommodate the organic electroluminescent portion to form a sealed space together with the substrate; A sealing member configured between the sealing cover and the contact surface of the substrate to improve the sealing force between the sealing cover and the substrate; A hygroscopic material installed in close contact with the inner surface of the encapsulation cover of the sealed space formed by the encapsulation cover; And a filler formed between the moisture absorbent and the organic electroluminescent part and in a sealed space formed by the substrate and the encapsulation cover, wherein the filler has an optical characteristic deviation within 10% of the moisture absorbent. Have

The moisture absorbent may be PNPL (Polymer Nano Porous Layer).

In addition, the optical properties of the filler includes any one or more of refractive index, water absorption.

Therefore, the filler has a density deviation so as to have a refractive index variation of less than 10% compared to the absorbent material, and the filler has an energy gap so as to have an absorbance variation within 10% of the absorbent material. .

In addition, the filler is chemically inert to the organic electroluminescent unit and the encapsulation cover.

Moreover, the filler has fluidity so as to be completely filled on the sealed space and the absorbent material.

Preferably, the filler is liquid crystal.

Hereinafter, exemplary embodiments of an organic light emitting diode display according to the present invention will be described in detail with reference to the accompanying drawings.

5 is a cross-sectional view of an organic light emitting display device in which a PNPL surface is unevenly formed, and FIG. 6 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment of the present invention.

Referring to FIG. 6, the organic light emitting diode display 20 according to the present invention includes a substrate 21, an organic electroluminescent unit 22 stacked on one surface of the substrate 21, and the organic electroluminescent unit 22. The encapsulation cover 23 which contacts on the outer periphery of the end of the substrate 21 to form an airtight space together with the substrate 21, to improve the sealing force between the encapsulation cover 23 and the substrate 21 to be accommodated. Sealing material 25 formed between the contact surface of the encapsulation cover 23 and the substrate 21, the moisture absorbing material 24 is installed in close contact with the inner surface of the encapsulation cover 23 of the sealed space formed of the encapsulation cover 23 and the Filler 27 is provided between the moisture absorbing material 24 and the organic electroluminescent portion 22 and in a sealed space formed of the substrate 21 and the encapsulation cover 23, the filler 27 Has an optical characteristic deviation within 10% of the absorbent material 24.

As shown in FIG. 5, the hygroscopic material 24 formed on the inner surface of the encapsulation cover 23 has a non-uniform surface due to its manufacturing limitation. The non-uniform surface of this moisture absorbing material 24 is the protrusion P which a part is affixed or formed on the surface which contact | connects the inner peripheral surface of the sealing cover 23. Due to the non-uniform surface of the absorbent material 24, the light emitted from the organic electroluminescent portion 22 is not uniformly transmitted to the viewer.

In the present invention, as shown in Figure 6, using the filler 27 solves the problems as described above. The filler 27 in the preferred embodiment of the present invention is liquid crystal, and the hygroscopic material 24 is PNPL. The liquid crystal 27 is filled between the PNPL 24 and the organic electroluminescent unit 22 and in a sealed space formed of the substrate 21 and the encapsulation cover 23. That is, when the substrate 21 on which the organic electroluminescent portion 22 is formed and the encapsulation cover 23 on which the PNPL 24 is formed are bonded together by using the sealing material 25, the internal space of the remaining residue formed therein becomes liquid crystal ( 27).

This liquid crystal 27 is intended to counteract the influence of the PNPL 24 having a non-uniform surface and has an optical characteristic deviation within 10% of the PNPL 24. The optical properties herein include any one or more of refractive index and absorbance.

To counteract the problem as described above, the liquid crystal 27 has a variation in optical characteristics similar to that of the PNPL 24, more precisely, a refractive index and an absorption rate of the PNPL 24 within ± 10%. The reason why the optical characteristics such as refractive index and absorptance have a deviation within ± 10% is because the deviation is such that the observer does not recognize it as a defect.

Typical optical properties are defined by the following formula.

[expression]

A + T + R + S = 1

Where A is an absorption index, T is a transmission index, R is a reflection index, and S is a scattering index. In particular, the reflection index R may be specified as the refractive index. Of these, the reflection index R and the scattering index S are factors to be considered for two or more media.

In the present invention, only the refractive index and the water absorption are mentioned. This is because only the absorption index, the transmission index, and the reflection index are taken into consideration while ignoring the influence of the relatively small scattering index. When the reflection index and the absorption index specified as the refractive index are specified, the reflection index is determined dependently.

Therefore, if the scattering index reaches a level which cannot be relatively overlooked, the reflection index or the scattering index may be further considered in order not to contradict the spirit of the present invention.

As one of the main factors for determining the refractive index, the density deviation of the liquid crystal 27 and the PNPL 24 is set to have a refractive index deviation within ± 10%. Since the density of the medium is a general factor for determining the refractive index, the refractive index may be similar when the density of both the media, that is, the liquid crystal 27 and the PNPL 24, are similar to each other.

In addition, the energy gaps of the liquid crystal 27 and the PNPL 24 are set to have absorbance deviations within ± 10% of each other. Herein, the energy gap E _g generally means an optical energy gap that can transmit light in the visible and near-visible region, and when the organic electroluminescent unit 22 is used for a specific purpose, that is, other than visible light In the case of having the organic electroluminescent unit 22 for emitting light of a region, an energy gap may be appropriate to pass the light of the region.

The liquid crystal 27 is chemically inert with respect to the organic electroluminescent portion 22 and the encapsulation cover 23. In use, since the material used as the filler, such as the liquid crystal 27, is chemically active with the organic electroluminescent portion 22 and the encapsulation cover 23, that is, when the chemical reaction occurs, the defective rate may be rather increased. Results are contrary to the spirit of the invention. Therefore, in the present invention, the liquid crystal 27 is chemically inert with the organic electroluminescent portion 22 and the encapsulation cover 23, and thus, the liquid crystal 27 must be stable even after fabrication or during operation.

In addition, the liquid crystal 27 is disposed between the PNPL 24 and the organic electroluminescent portion 22 and in an enclosed space formed of the substrate 21 and the encapsulation cover 23, that is, the organic electroluminescent portion 22 When the encapsulation cover 23 formed with the formed substrate 21 and the PNPL 24 is bonded together using the sealant 25, it has fluidity so that it can be completely filled in the internal space of the remainder configured therefrom. This is because when the filling is not completely filled or filled with pores therein, a large variation in optical properties may occur. That is, when unfilled spaces or internal pores are generated, the optical characteristics in the liquid crystal 27 and the optical characteristics in the non-filled region are greatly different, so that the optical characteristic deviation is greater at the interface between both regions. May be caused. Therefore, in order to prevent such a problem, the liquid crystal 27 must have fluidity so as to be sufficiently filled in the internal space.

The foregoing is merely illustrative of the preferred embodiments of the present invention and those skilled in the art to which the present invention pertains recognize that modifications and variations can be made to the present invention without departing from the spirit and gist of the invention as set forth in the appended claims. shall.

As described above, the organic light emitting display device according to the present invention enables uniform external light emission by allowing light emitted from the organic electroluminescent unit to pass through a filler and an absorbent having mutually similar optical characteristics.

Claims (9)

Board; An organic electroluminescent unit stacked on one surface of the substrate; An encapsulation cover contacting the outer periphery of the end of the substrate to accommodate the organic electroluminescent portion to form a sealed space together with the substrate; A sealing member configured between the sealing cover and the contact surface of the substrate to improve the sealing force between the sealing cover and the substrate; Hygroscopic material is installed in close contact with the inner surface of the sealing cover of the sealed space formed by the sealing cover; And A filler formed between the hygroscopic material and the organic electroluminescent part and filled in a sealed space formed by the substrate and the encapsulation cover, And the filler has an optical characteristic deviation within 10% of the hygroscopic material. The method of claim 1, The moisture absorbing material is a PNPL (Polymer Nano Porous Layer). delete The method of claim 1, The optical characteristic of the optical material having a deviation within 10% of the filler and the hygroscopic material comprises at least one of refractive index and absorbance. The method of claim 4, wherein The filler has a density deviation such that the filler has a refractive index variation within 10% of the moisture absorbent. The method of claim 4, wherein The filler has an energy gap such that the filler has a variation in absorption rate within 10% of the moisture absorbent. The method of claim 1, The filler is chemically inert to the organic light emitting unit and the encapsulation cover. The method of claim 1, And the filler is fluid so as to be completely filled in the enclosed space and the moisture absorbent. The method of claim 1, The filler is an organic light emitting display device.

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