KR20090000945A - Organic light emitting diode display device and method of manufacturing the same - Google Patents

Abstract

A displaying device for an organic luminance diode and a method of manufacture thereof are provided to facilitate controlling a micro cavity by forming an optics buffer layer on a sealing substrate after forming an organic light-emitting diode device. A displaying device for an organic luminance diode comprises a first substrate(100), a organic light-emitting diode device(E), a second substrate(130) and an optics buffer layer(140). The first substrate has a plurality of pixels(P1,P2,P3). The organic light-emitting diode device is arranged in each pixel. The organic light-emitting diode device forms light. The second substrate is attached to the first substrate. The second substrate emits the light formed by the organic light-emitting diode device. The optics buffer layer is arranged in one or more sides of the second substrate.

Description

Organic light emitting diode display and manufacturing method thereof {ORGANIC LIGHT EMITTING DIODE DISPLAY DEVICE AND METHOD OF MANUFACTURING THE SAME}

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

2 illustrates EL spectra measured from first and second organic light emitting diode display devices, respectively.

3 is a diagram illustrating color coordinates measured from the first and second organic light emitting diode display devices, respectively.

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

5 are diagrams of EL spectra respectively measured from the third and fourth organic light emitting diode display devices.

6 is a diagram illustrating color coordinates measured from the third and fourth organic light emitting diode display devices, respectively.

7A to 7C are diagrams illustrating a method of manufacturing an organic light emitting diode display according to a third exemplary embodiment of the present invention.

 (Explanation of symbols for the main parts of the drawing)

 100 substrate 105 first electrode

 110: optical buffer layer 115: organic light emitting pattern

 125: second electrode 130: second substrate

 140, 240: optical buffer layer

The present invention relates to an organic light emitting diode display. More particularly, the present invention relates to an organic light emitting diode display capable of improving optical characteristics and a method of manufacturing the same.

The display device provides the image information to the user. Such display devices include liquid crystal display devices, field emission display devices, organic light emitting diodes display devices, plasma display devices, and the like. do.

In particular, the organic light emitting diode display is self-luminous and does not require a backlight such as an LCD, so that it is not only lightweight but also can be manufactured by a simple process. In addition, organic light emitting diode display devices are rapidly rising as next generation displays due to low voltage driving, high luminous efficiency, and wide viewing angle.

The organic light emitting diode display includes an anode, an organic light emitting layer, and a cathode sequentially formed on a substrate. Either one of the two electrodes is formed of a transparent conductive material. In the organic light emitting diode display, holes and electrons respectively provided at the anode and the cathode recombine in the organic light emitting layer to generate light. In this case, the light is emitted to the outside through the electrode and the substrate formed of a transparent conductive material, to provide an image to the user.

Here, when the light is emitted above the critical angle, the light causes total reflection at the interface between the transparent electrode having a high refractive index and the substrate having a low refractive index. Due to this total reflection, about one quarter of the light formed in the organic light emitting layer is emitted to the outside. Accordingly, the organic light emitting diode display has a problem in that optical characteristics, that is, light reproducibility and light efficiency are lowered.

Here, when the light efficiency is lowered, the luminance of the organic light emitting diode display is lowered, and the driving voltage of the organic light emitting diode display is increased in order to increase the luminance of the organic light emitting diode display. In this case, when the driving voltage is increased, the organic light emitting layer may be deteriorated, and thus the lifespan of the organic light emitting diode display may be reduced.

SUMMARY OF THE INVENTION An object of the present invention is to provide an organic light emitting diode display device capable of improving optical characteristics.

In order to achieve the above technical problem, an aspect of the present invention provides an organic light emitting diode display. The organic light emitting diode display device includes a first substrate having a plurality of pixels, an organic light emitting diode element disposed at each pixel to form light, a second substrate bonded to the first substrate and emitting the light, and the second substrate. Two optical buffer layers disposed on at least one side of the substrate.

In order to achieve the above technical problem, an aspect of the present invention provides a method of manufacturing an organic light emitting diode display. The manufacturing method includes providing a first substrate having a plurality of pixels, forming an organic light emitting diode element in each pixel, providing a second substrate corresponding to the first substrate, Forming an optical buffer layer on at least one surface, and bonding the second substrate to the first substrate.

Hereinafter, embodiments of the present invention will be described in more detail with reference to the drawings of an organic light emitting diode display. The following embodiments are provided as examples to sufficiently convey the spirit of the present invention to those skilled in the art. Accordingly, the invention is not limited to the embodiments described below and may be embodied in other forms. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like numbers refer to like elements throughout.

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

Referring to FIG. 1, the organic light emitting diode display of the present invention includes a first substrate 100, an organic light emitting diode device E, a second substrate 130, and an optical buffer layer 140.

The first substrate 100 includes a plurality of pixels for displaying an image. The plurality of pixels may include red, green, and blue pixels P1, P2, and P3. Examples of the material of the first substrate 100 may be plastic, glass, metal, or the like.

In the drawings, for convenience of description, driving devices for applying a driving signal to each of the organic light emitting diode devices E are not illustrated, and description thereof will be omitted herein.

The organic light emitting diode element E is disposed on the first substrate 100 corresponding to each pixel P1, P2, P3. The organic light emitting diode device E includes a first electrode 105, an organic light emitting pattern 115, and a second electrode 125 sequentially disposed on the first substrate 100. The first electrode 105 is disposed at each pixel P1, P2, P3 separately. The first electrode 105 may be made of a conductive material that reflects light. In this case, the first electrode 105 may be made of a conductive material having a lower work function than the second electrode 125 to be described later. For example, the first electrode 105 may be made of Al, AlNd, Mg, Ag, or the like. A bank pattern 110 exposing a portion of the first electrode 105 may be further disposed on the first substrate 100 including the first electrode 105. That is, the bank pattern 110 covers the edge of the first electrode 105 and is disposed on the first substrate 100. As a result, the bank pattern 110 may prevent the first electrode 105 and the second electrode 125 from shorting. The organic light emitting pattern 115 is disposed on at least the first electrode 105 exposed by the bank pattern 110. The organic light emitting pattern 115 may include red, green, and blue organic light emitting patterns disposed on the red, green, and blue pixels P1, P2, and P3, respectively. The second electrode 125 is disposed on the organic light emitting pattern 115. The second electrode 125 may be a common electrode integrally formed with respect to each of the pixels P1, P2, and P3. In this case, the second electrode 125 may be formed of a transparent conductive material that may transmit light. In addition, the second electrode 125 may be formed of a conductive material having a larger work function than the first electrode 105. For example, the second electrode 125 may be formed of ITO or IZO.

In addition, the organic light emitting diode device E includes at least one of a first charge injection layer and a first charge transport layer between the first electrode 105 and the organic light emitting pattern 115 to improve luminous efficiency and lifespan. can do. In addition, at least one of the second charge injection layer and the second charge transport layer may be further included between the organic light emitting pattern 115 and the second electrode 125.

The organic light emitting diode device E is sealed with an external rotor, and the second substrate 130 is bonded to the first substrate 100. As a result, the organic light emitting diode device E can be prevented from being oxidized by external moisture and oxygen, thereby improving the lifespan and reliability of the organic light emitting diode display device. The second substrate 130 may be bonded by a sealing member (not shown) disposed along the edge portion of the first substrate 100.

Therefore, the organic light emitting diode display device according to the present invention emits light from the organic light emitting diode device E provided on the first substrate 100 to the second substrate 130 to provide an image. top emission type). The top emission method has an advantage of having a larger aperture ratio than the bottom emission type that provides an image to the first substrate 100.

The optical buffer layer 140 is disposed on the inner surface of the second substrate 130. Here, unlike the drawing, the optical buffer layer 140 may be disposed on the outer surface of the second substrate 130. In this case, the optical buffer layer 140 is formed of a transflective film. For example, the optical buffer layer 140 may be formed of at least one layer selected from a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, and a titanium oxide (TiOx) film. Alternatively, the optical buffer layer 140 may be a laminated film including at least one selected from a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, and a titanium oxide (TiOx) film.

Accordingly, the organic light emitting diode display may have a micro-cavity that causes mutual interference of light between the first electrode 105 and the optical buffer layer 140. The microcavity may enhance a specific wavelength to improve color purity and light efficiency of the organic light emitting diode display. That is, the first light, which is part of the light formed in the organic light emitting diode device E, passes directly through the optical buffer layer 140. The second light, which is the remaining part, is reflected by the optical buffer layer 140 and is incident to the first electrode 105. Thereafter, the light incident on the first electrode 105 is reflected back to the first electrode 105 to be incident again to the optical buffer layer 140, and then reflected again by the first electrode 105. As such, the light formed in the organic light emitting diode device may cause constructive interference while repeating the reflection process in the first electrode 105 and the optical buffer layer 140, and thus the amplified light may be emitted to the outside to improve light efficiency. .

Here, when the phases of the first light and the second light are different, the first light and the second light cancel each other and thus the light efficiency may be lowered. Thus, in order to optimize the microcavity effect, the design of the optical buffer layer 140 is important.

Optimization of the micro cavity effect can be adjusted by the thickness of the optical buffer layer 140. In this case, the thickness of the optical buffer layer 140 may be formed to have a uniform thickness for all pixels. Here, in consideration of the color purity, the thickness of the optical buffer layer 140 may be 150 to 450nm.

2 and 3 illustrate optical characteristics of a first organic light emitting diode display having an optical buffer layer having a uniform thickness and a second organic light emitting diode display having no optical buffer layer. In the first organic light emitting diode display, the thickness of the optical buffer layer 140 was 300 nm. The optical buffer layer 140 was formed of a silicon nitride film having a refractive index of 1.896.

2 illustrates EL spectra measured from first and second organic light emitting diode display devices, respectively.

Referring to FIG. 2, the EL spectrums RM1, GM1, and BM1 of the first organic light emitting diode display are narrower than the EL spectra R1, G1, and B1 of the second organic light emitting diode display. That is, the organic light emitting diode display device was found to have improved color reproducibility as the optical buffer layer was provided.

3 is a diagram illustrating color coordinates measured from the first and second organic light emitting diode display devices, respectively.

Referring to FIG. 3, the color reproduction rate measured from the color coordinate M1 of the first organic light emitting diode display device was 82.9%, and the color reproduction rate measured from the color coordinate NM1 of the second organic light emitting diode display device was 75.2%. That is, as the organic light emitting diode display device includes the optical buffer layer, the color reproducibility increased to 7.7%.

Therefore, in the embodiment of the present invention, as the optical buffer layer is provided on the inner surface or the outer surface of the second substrate 130, color reproducibility and light efficiency may be improved. In addition, it is possible to form the optical buffer layer after the organic light emitting diode element is formed. Thus, after measuring the optical characteristics of the completed organic light emitting diode device, it is possible to change the design and design value of the optical buffer layer to have an optimized micro-cavity effect. As a result, the process can be simplified, and optical errors of the organic light emitting diode display can be reduced.

4 is a cross-sectional view of an organic light emitting diode display according to a second exemplary embodiment of the present invention. The second embodiment of the present invention has the same configuration as the first embodiment described above except for the optical buffer layer. Therefore, the same components are assigned the same reference numerals, and repeated descriptions are omitted.

Referring to FIG. 4, the organic light emitting diode display includes a first substrate 100 including a plurality of pixels, an organic light emitting diode device, an optical buffer layer 240, and a second substrate 130.

The optical buffer layer 240 is disposed on the inner surface or the outer surface of the second substrate 130 to enhance specific wavelengths of light formed from the organic light emitting diode device E, thereby improving light efficiency and color reproducibility. In this case, since the organic light emitting diode display has pixels P1, P2, and P3 that form red, green, and blue colors, respectively, in order to realize full-color, the optical buffer layer 240 includes the pixels P1, P2, and P3. ), The wavelength to be augmented varies. Thus, in order to further improve the color reproducibility of the organic light emitting diode display, the thickness of the optical buffer layer 240 must be adjusted for each pixel. This is because the length of the augmented wavelength increases with the thickness of the optical buffer layer 240.

Accordingly, the optical buffer layer 240 includes first, second and third optical buffer layers 240a, 240b and 240c corresponding to the red, green and blue pixels P1, P2 and P3, respectively. The second and third optical buffer layers 240a, 240b, and 240c may have different thicknesses corresponding to the pixels P1, P2, and P3, respectively. Here, when the first, second and third optical buffer layers 240a, 240b, 240c are formed to different thicknesses, the process may be complicated. Thus, two optical buffer layers among the first, second and third optical buffer layers 240a, 240b, and 240c may have different thicknesses. For example, the second and third optical buffer layers 240b and 240c may have the same thickness, and the first optical buffer layer 240a may have a different thickness from the second and third optical buffer layers 240b and 240c. have.

Unlike the drawings, the first, second and third optical buffer layers 240a, 240b and 240c may be formed to have different thicknesses. Since the red wavelength is the largest and the blue wavelength is the smallest, the thickness of the first optical buffer layer 240a among the first, second, and third optical buffer layers 240a, 240b, and 240c is the largest, and the third optical buffer layer is The thickness of 240c may be the smallest.

Therefore, at least two optical buffer layers of the first, second and third optical buffer layers 240a, 240b and 240c may be formed to have different thicknesses.

The thicknesses of the first, second and third optical buffer layers 240a, 240b and 240c may be 350 nm to 450 nm, 150 nm to 450 nm, and 150 to 250 nm, respectively. In this case, when the first, second, and third optical buffer layers 240a, 240b, and 240c are outside the thickness ranges, color purity may decrease.

The first, second and third optical buffer layers 240a, 240b and 240c may be formed of at least one layer selected from a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, and a titanium oxide (TiOx) film. Alternatively, the first, second and third optical buffer layers 240a, 240b, and 240c may be laminated films including at least one selected from a silicon oxide (SiOx) film, a silicon nitride (SiNx) film, and a titanium oxide (TiOx) film. Can be. For example, the first, second, and third optical buffer layers 240a, 240b, and 240c may be formed as double layers of a silicon nitride film and a silicon oxide film.

5 and 6 illustrate a third organic light emitting diode display having first, second and third optical buffer layers 240a, 240b, and 240c and a fourth organic light emitting diode display having no optical buffer layer 240. Figures comparing the optical properties of the. Here, the thicknesses of the first, second and third optical buffer layers 240a, 240b and 240c were 400 nm, 200 nm and 200 nm, respectively. In this case, the optical buffer layer 240 is formed of a silicon nitride film having a refractive index of 1.896.

5 are diagrams of EL spectra respectively measured from the third and fourth organic light emitting diode display devices.

Referring to FIG. 5, the EL spectra R2, G2 and B2 of the fourth organic light emitting diode display are wider than the EL spectra RM2, GM2 and BM2 of the third organic light emitting diode display. That is, as the organic light emitting diode display device includes the optical buffer layer 240, the color reproducibility was improved.

6 is a diagram illustrating color coordinates measured from the third and fourth organic light emitting diode display devices, respectively.

Referring to FIG. 6, the color reproduction rate measured from the color coordinates of the fourth organic light emitting diode display device NM2 was 75.2%, and the color reproduction rate measured from the color coordinates of the third organic light emitting diode display device M2 was 94.9%. That is, as the organic light emitting diode display device includes an optical buffer layer having a different thickness for each pixel, the color reproducibility increases to 19.7%.

Therefore, in the embodiment of the present invention, since the optical buffer layer 140 having different thicknesses for each pixel is provided on the inner side or the outer side of the second substrate 130, color reproduction and light efficiency may be improved.

7A to 7C are diagrams illustrating a method of manufacturing an organic light emitting diode display according to a third exemplary embodiment of the present invention.

Referring to FIG. 7A, a first substrate 100 in which a plurality of pixels are defined is provided. The plurality of pixels may include red, green, and blue pixels P1, P2, and P3. Here, examples of the material used as the first substrate 100 may be plastic, glass, metal, or the like.

In the drawings, for convenience of description, driving devices for applying a driving signal to each organic light emitting diode device E are not illustrated, and a description thereof will be omitted herein.

An organic light emitting diode element E is formed on the first substrate 100 corresponding to each pixel. In order to form the organic light emitting diode device E, first, the first electrode 105 is formed on the first substrate 100. Here, the first electrode 105 may be formed separately in each pixel P1, P2, and P3. The first electrode 105 may be formed of a conductive material having a lower work function than the second electrode 125 formed in a subsequent process. For example, the first electrode 105 may be formed of Al, AlNd, Mg, Ag, or the like. In this case, the first electrode 105 may be formed through a sputtering method or a vacuum deposition method. Thereafter, the bank pattern 110 is formed on the first substrate 100 to cover the edge portion of the first electrode 105. In order to form the bank pattern 110, an organic insulating layer is formed on the first substrate 100 including the first electrode 105. Subsequently, an exposure and development process are performed on the first substrate 100 including the organic insulating layer to form a bank pattern 110 between the pixels P1, P2, and P3 and in an edge region of the first electrode 105. do. Thereafter, the organic light emitting pattern 115 is formed on the first electrode 105. In order to form the organic light emitting pattern 115, red, green, and blue organic light emitting patterns are formed on the red, green, and blue pixels P1, P2, and P3, respectively. The red, green, and blue organic light emitting patterns include organic light emitting materials that form red light, green light, and blue light, respectively. Here, the red, green, and blue organic light emitting patterns may be formed through a vacuum deposition method or an inkjet printing method using a shadow mask. Thereafter, the second electrode 125 is formed on the first substrate 100 including the organic light emitting pattern 115. The second electrode 125 may be formed of a conductive material having a larger work function than the first electrode 105. For example, the second electrode 125 may be formed of ITO or IZO. In this case, the second electrode 125 may be formed through a sputtering method.

In addition, the organic light emitting diode E may further include at least one of the first charge injection layer and the first charge transport layer between the first electrode 105 and the organic light emitting pattern 115 in order to improve light emission efficiency and lifespan. Can be formed. In addition, at least one of the second charge injection layer and the second charge transport layer may be further formed between the organic light emitting pattern 115 and the second electrode 125. Here, the first and second charge injection layers and the first and second charge transport layers may be formed by vacuum deposition or coating.

Referring to FIG. 7B, a second substrate 130 corresponding to the first substrate 100 is provided. The second substrate 130 may be made of a transparent material that transmits light. Examples of the material used as the second substrate 130 may be plastic and glass.

An optical buffer layer 140 capable of transflecting may be formed on one surface of the second substrate 130, for example, an inner surface or an outer surface thereof.

Here, the optical buffer layer 240 is the first, second and third optical buffer layer 240a, 240b, 240c corresponding to the red, green, and blue pixels P1, P2, and P3 on the second substrate 130, respectively. ) May be included. In this case, at least two optical buffer layers of the first, second and third optical buffer layers 240a, 240b and 240c may have different thicknesses. For example, for color reproducibility and process convenience, the second and third optical buffer layers 240b and 240c have the same thickness, and the first optical buffer layer 240a has the second and third optical buffer layers 240b. , 240c).

In order to form the optical buffer layer 240, a transflective film is formed on the second substrate 130. Examples of the material for forming the transflective film may be a silicon oxide film, silicon nitride, titanium oxide, or the like. In this case, the semi-permeable membrane may be formed through sputtering or chemical vapor deposition. In addition, the optical buffer layer 240 may be formed of a laminated film having different refractive indices. Thereafter, photosensitive patterns having different thicknesses are formed on the transflective film. The photosensitive pattern may be formed through a halftone mask. Thereafter, the semi-transmissive layer is etched using the photosensitive pattern as an etch mask to form an optical buffer layer 240 including first, second and third optical buffer layers 240a, 240b and 240c.

Here, unlike the drawing, the optical buffer layer 240 may be formed to have a uniform thickness on the entire surface of the second substrate 130. Alternatively, the first, second and third optical buffer layers 240a, 240b and 240c may be formed to have different thicknesses corresponding to each pixel.

Referring to FIG. 7C, a second substrate 130 is provided on the organic light emitting diode device E of the first substrate 100. Thereafter, the second substrate 130 is bonded onto the first substrate 100 to seal the organic light emitting diode device E from the outside. In this case, the optical buffer layer 240 may be disposed on the inner surface of the second substrate 130 to face the organic light emitting diode device (E). Alternatively, the optical buffer layer 240 may be disposed on the outer surface of the second substrate 130.

Therefore, in the embodiment of the present invention, as the optical buffer layer 240 is disposed on the second substrate 130, the microcavity effect may be expected without affecting the organic light emitting diode device E. In addition, after the organic light emitting diode device E is formed, the design of the optical buffer layer 140 may be easily changed by forming the optical buffer layer 240. As a result, the optical error of the organic light emitting diode display can be reduced.

As described above, the organic light emitting diode display according to the present invention includes an optical buffer layer for forming a microcavity in an encapsulation substrate through which light is emitted and sealing the organic light emitting diode device to the outside, thereby providing an aperture ratio of the organic light emitting diode display. It was possible to secure the optical properties.

In addition, since the optical buffer layer is provided on the encapsulation substrate, the organic light emitting diode device may not be directly affected, and the optical characteristics may be easily controlled, and the optical characteristics may be improved.

In addition, since the optical buffer layer may be formed on the encapsulation substrate after the formation of the organic light emitting diode device, it is easy to control the microcavity and reduce the optical error of the organic light emitting diode display device.

Claims (9)

A first substrate having a plurality of pixels; An organic light emitting diode element disposed in each pixel to form light; A second substrate bonded to the first substrate and emitting the light; And And an optical buffer layer disposed on at least one surface of the second substrate. The method of claim 1, And the optical buffer layer comprises a single layer or at least one or more layers of at least one of a silicon oxide film, a silicon nitride film, and a titanium oxide film. The method of claim 1, And the optical buffer layer is disposed to have a uniform thickness for each pixel. The method of claim 3, wherein The thickness of the optical buffer layer has an organic light emitting diode display device having a range of 150nm to 450nm. The method of claim 1, The optical buffer layer includes first, second, and third optical buffer layers respectively corresponding to the first, second, and third pixels having light having different wavelengths, and among the first, second, and third optical buffer layers. And at least two optical buffer layers having different thicknesses. The method of claim 5, wherein The thickness of the first optical buffer layer has a range of 350 to 450nm, the thickness of the second optical buffer layer has a range of 150nm to 450nm, the thickness of the third optical buffer layer has a range of 150nm to 250nm. Organic light emitting diode display. Providing a first substrate having a plurality of pixels; Forming an organic light emitting diode device in each pixel; Providing a second substrate corresponding to the first substrate; Forming an optical buffer layer on at least one side of the second substrate; And And attaching a second substrate to the first substrate. The method of claim 7, wherein And the optical buffer layer is formed to have a uniform thickness for each pixel. The method of claim 7, wherein The optical buffer layer includes first, second, and third optical buffer layers respectively corresponding to the first, second, and third pixels having light having different wavelengths, and among the first, second, and third optical buffer layers. And at least two optical buffer layers have different thicknesses.

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