KR102289701B1 - Organic light emitting display device and method of fabricating the same - Google Patents

Abstract

The organic light emitting display device of the present invention and its manufacturing method use a silicon nitride film (SiNx) having a transmittance and refractive index similar to that of indium-tin-oxide (ITO) and have different transmittance and refractive index for each sub-pixel in one mask process It is characterized in that to form an optical compensation layer having a.
According to the present invention, in an organic light emitting display device having a micro cavity structure, a color viewing angle, color gamut and efficiency are improved, and a process is simplified.

Description

Organic light emitting display device and manufacturing method thereof

The present invention relates to an organic light emitting display device and a method of manufacturing the same, and more particularly, to an organic light emitting display having a micro cavity structure and a method of manufacturing the same.

Recently, as interest in information display is rising and the demand to use portable information media increases, it has been applied to a lightweight, thin flat panel display (FPD) replacing the conventional display device, a cathode ray tube (CRT). Research and commercialization are focused on.

In such a flat panel display field, a liquid crystal display device (LCD), which is light and low power consumption, has been the most attractive display device until now, but the liquid crystal display device is a light receiving device, not a light emitting device, and is ) and viewing angle, the development of a new display device capable of overcoming these disadvantages is being actively developed.

The organic light emitting display device, one of the new display devices, is a self-luminous type, so it has superior viewing angle and contrast ratio compared to the liquid crystal display device. . In addition, it has the advantage of being able to drive at a low DC voltage and having a fast response speed, and in particular, it has an advantage in terms of manufacturing cost.

Unlike a liquid crystal display or a plasma display panel (PDP), in the manufacturing process of the organic light emitting display device, the deposition and encapsulation processes are all processes, so the manufacturing process is very simple. In addition, when the organic light emitting display device is driven in an active matrix method having a thin film transistor (TFT) as a switching element for each sub-pixel, the same luminance even when a low current is applied , so it has the advantages of low power consumption, high cost and large size.

Hereinafter, the basic structure and operation characteristics of the organic light emitting display device will be described in detail with reference to the drawings.

1 is a diagram illustrating a light emitting principle of a general organic light emitting diode.

In general, an organic light emitting display device includes an organic light emitting diode as shown in FIG. 1 .

In this case, the organic light emitting diode includes an anode 18 as a pixel electrode, a cathode 28 as a common electrode, and organic layers 30a, 30b, 30c, 30d, and 30e formed therebetween.

In addition, the organic layers 30a, 30b, 30c, 30d, 30e are a hole transport layer (HTL) 30b and an electron transport layer (ETL) 30d and a hole transport layer 30b and an electron transport layer ( 30d) and an Emission Layer (EML) 30c interposed therebetween.

At this time, in order to improve luminous efficiency, a hole injection layer (HIL) 30a is interposed between the anode 18 and the hole transport layer 30b, and electrons are interposed between the cathode 28 and the electron transport layer 30d. An Electron Injection Layer (EIL) 30e is interposed.

In the organic light emitting diode configured in this way, when positive (+) and negative (-) voltages are applied to the anode 18 and the cathode 28, respectively, the holes passing through the hole transport layer 30b and the electron transport layer 30d pass through One electron moves to the light emitting layer 30c to form an exciton, and when the exciton transitions from an excited state to a ground state, that is, to a stable state, light is generated.

The organic light emitting display device displays an image by arranging sub-pixels having the organic light emitting diodes having the above-described structure in a matrix form and selectively controlling the sub-pixels with a data voltage and a scan voltage.

In this case, the organic light emitting display device is divided into a passive matrix method or an active matrix method using a thin film transistor as a switching device. Among them, the active matrix method selects a sub-pixel by selectively turning on a thin film transistor, which is an active element, and maintains light emission of the sub-pixel with a voltage maintained in the storage capacitor.

On the other hand, there is an organic light emitting display device having a micro-cavity structure to increase efficiency by generating multiple reflection interference between a reflective film and a semi-transmissive film, which will be described in detail with reference to the drawings below.

2 is a cross-sectional view schematically showing the structure of an organic light emitting display device having a general micro-cavity structure, and showing an organic light emitting display device of a bottom emission type using a color filter as an example.

Referring to FIG. 2 , one pixel includes a red sub-pixel SPr, a green sub-pixel SPg, and a blue sub-pixel SPb.

A switching transistor (not shown), a driving transistor (not shown), and a capacitor (not shown) are formed in each of the sub-pixels SPr, SPg, and SPb.

The red sub-pixel SPr, the green sub-pixel SPg, and the blue sub-pixel SPb of the substrate 1 on which the switching transistor, the driving transistor and the capacitor are formed have a red sub-color filter R and a green sub-pixel, respectively. - A color filter (G) and a blue sub-color filter (B) are formed.

An overcoat layer 15d is formed on the substrate 10 on which the red sub-color filter R, the green sub-color filter G, and the blue sub-color filter B are formed.

An organic light emitting diode is formed in each of the sub-pixels SPr, SPg, and SPb on which the overcoat layer 15d is formed.

The organic light emitting diode operates to emit light according to a driving current formed by the driving transistor.

The organic light emitting diode includes first electrodes 18r, 18g, 18b, an organic light emitting layer 30 and a second electrode 28 .

A bank 15e is formed on the substrate 1 on which the first electrodes 18r, 18g, and 18b are formed.

In this case, first electrodes 18r, 18g, and 18b are formed in each of the sub-pixels SPr, SPg, and SPb to have different thicknesses for each of the sub-pixels SPr, SPg, and SPb. That is, in order to match the color viewing angle and the color gamut using the micro-cavity phenomenon, the transmittance is varied or a separate layer is formed on the sub-pixels SPr, SPg, and SPb. For example, the first electrode 18b of the blue sub-pixel SPb is composed of a single layer, while the first electrode 18g of the green sub-pixel SPg is composed of two layers, and the red sub-pixel ( The first electrode 18r of SPr) is composed of three layers.

As described above, in the related art, the thickness of the first electrode 18r, 18g, 18b or the second electrode 28 is applied differently or the thickness of the organic light emitting layer 30 is applied differently for each sub-pixel (SPr, SPg, SPb). That is, the first electrode 18r, 18g, 18b, the second electrode 28, or the organic light emitting layer 30 for each sub-pixel (SPr, SPg, SPb) in consideration of the color viewing angle and the lifespan of the organic light emitting diode. ) must be applied differently.

In this case, for example, since the thicknesses of the first electrodes 18r, 18g, and 18b must be different for each sub-pixel SPr, SPg, and SPb, at least three depositions and three mask processes are required.

As such, the number of mask processes is further increased compared to an organic light emitting display device without a micro-cavity structure.

An object of the present invention is to provide an organic light emitting diode display having a highly efficient micro cavity structure through a single mask process and a method for manufacturing the same.

In addition, other objects and features of the present invention will be described in the following description of the invention and claims.

In order to achieve the above object, an organic light emitting display device according to an embodiment of the present invention provides a substrate in which red, green, and blue sub-pixels are partitioned in a matrix form, and a first electrode disposed in each of the sub-pixels of the substrate. , an optical compensation layer disposed above or below the first electrode, an organic emission layer disposed on the first electrode, and a second electrode disposed on a substrate on which the organic emission layer is disposed.

In this case, the optical compensation layer is characterized in that it has a stacked structure of a first silicon nitride film and a second silicon nitride film.

In this case, the optical compensation layer is characterized in that it has a different thickness for each red, green, and blue sub-pixel.

The organic light emitting display device according to an embodiment of the present invention may further include red, green, and blue sub-color filters respectively disposed in the red, green, and blue sub-pixels.

In this case, the light compensation layer may be positioned between the first electrode and the sub-color filter.

The light compensation layer may be positioned between the second electrode and the organic light emitting layer.

The first silicon nitride layer may be porous, and the second silicon nitride layer may have a higher density than the first silicon nitride layer.

The optical compensation layer is a first optical compensation layer in which a first silicon nitride film and a second silicon nitride film are laminated once on a blue sub-pixel, and a second light in which a first silicon nitride film and a second silicon nitride film are laminated twice on a green sub-pixel. It may include a compensation layer and a third optical compensation layer in which the first silicon nitride layer and the second silicon nitride layer are stacked three times on the red sub-pixel.

A method of manufacturing an organic light emitting display device according to an embodiment of the present invention includes providing a substrate in which red, green, and blue sub-pixels are partitioned in a matrix form, and forming a first electrode in each of the sub-pixels of the substrate. Step, forming an optical compensation layer having a stacked structure of a first silicon nitride film and a second silicon nitride film on an upper or lower portion of the first electrode, forming an organic light emitting layer on the first electrode and on a substrate on which the organic light emitting layer is formed and forming a second electrode.

In this case, the optical compensation layer may have different thicknesses for each of the red, green, and blue sub-pixels.

In this case, the step of forming the optical compensation layer includes alternately stacking the first silicon nitride layer and the second silicon nitride layer at least three times on the substrate, and the substrate on which the first silicon nitride layer and the second silicon nitride layer are formed using a half-tone mask. forming a first photoresist film pattern having a first thickness and a second photoresist film pattern having a second thickness thereon, using the first photoresist film pattern and the second photoresist film pattern as a mask, a pair of first silicon nitride films and second films of blue sub-pixels removing the silicon nitride film, removing the first photoresist film pattern through ashing and simultaneously forming a third photoresist film pattern of a third thickness, and a pair of blue sub-pixels and green sub-pixels using the third photoresist film pattern as a mask and removing the first silicon nitride film and the second silicon nitride film.

In this case, the first silicon nitride layer may be removed using dry etching, and the second silicon nitride layer may be removed using wet etching.

A pair of first and second silicon nitride films remain in the blue sub-pixel to form a first light compensation layer, and in the green sub-pixel, two pairs of first and second silicon nitride films remain in the second light A compensation layer is formed, and three pairs of the first silicon nitride layer and the second silicon nitride layer remain in the red sub-pixel to form a third optical compensation layer.

As described above, an organic light emitting display device and a method for manufacturing the same according to an embodiment of the present invention use a silicon nitride film (SiNx) having a transmittance and refractive index similar to that of indium-tin-oxide (ITO) in one mask process. It is characterized in that the optical compensation layer having different transmittance and refractive index for each sub-pixel is formed.

Accordingly, in the organic light emitting display device having a micro-cavity structure, a color viewing angle, color gamut, and efficiency are improved, and the process is simplified.

1 is a diagram illustrating the light emitting principle of a general organic light emitting diode.
2 is a cross-sectional view schematically illustrating the structure of an organic light emitting display device having a general micro-cavity structure;
3 is a block diagram schematically showing an organic light emitting display device according to the present invention.
4 is an exemplary diagram showing a circuit configuration of a sub-pixel of an organic light emitting display device;
5 is a cross-sectional view schematically illustrating a structure of an organic light emitting display device according to a first embodiment of the present invention;
6 is a cross-sectional view schematically showing another structure of an organic light emitting display device according to a first embodiment of the present invention;
7 is a cross-sectional view schematically illustrating the structure of one sub-pixel in the organic light emitting display device according to the first embodiment of the present invention shown in FIG. 5;
8A to 8I are cross-sectional views sequentially illustrating a method of manufacturing the organic light emitting display device according to the first embodiment of the present invention shown in FIG. 5;
9 is a cross-sectional view schematically showing the structure of an organic light emitting display device according to a second embodiment of the present invention.
10 is a cross-sectional view schematically illustrating the structure of one sub-pixel in the organic light emitting display device according to the second embodiment of the present invention shown in FIG. 9;

Hereinafter, preferred embodiments of an organic light emitting display device and a method for manufacturing the same according to the present invention will be described in detail with reference to the accompanying drawings so that those of ordinary skill in the art can easily carry out the present invention.

Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described below in detail in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, but will be implemented in various different forms, and only these embodiments allow the disclosure of the present invention to be complete, and common knowledge in the art to which the present invention pertains It is provided to fully inform those who have the scope of the invention, and the present invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout. The sizes and relative sizes of layers and regions in the drawings may be exaggerated for clarity of description.

Reference to an element or layer to another element or “on” or “on” includes not only directly on the other element or layer, but also with other layers or other elements interposed therebetween. do. On the other hand, reference to an element "directly on" or "directly on" indicates that there are no intervening elements or layers.

The spatially relative terms "below, beneath", "lower", "above", "upper", etc. are one element or component as shown in the drawings. and can be used to easily describe the correlation with other devices or components. Spatially relative terms should be understood as terms including different orientations of the device during use or operation in addition to the orientation shown in the drawings. For example, if an element shown in the figures is turned over, an element described as "beneath" or "beneath" another element may be placed "above" the other element. Accordingly, the exemplary term “below” may include both directions below and above.

The terminology used herein is for the purpose of describing the embodiments, and thus is not intended to limit the present invention. As used herein, the singular also includes the plural unless specifically stated otherwise in the phrase. As used herein, “comprise” and/or “comprising” refers to the presence of one or more other components, steps, operations and/or elements mentioned. or addition is not excluded.

3 is a block diagram schematically illustrating an organic light emitting display device according to the present invention.

Referring to FIG. 3 , the organic light emitting display device according to the present invention includes an image processing unit 115 , a data conversion unit 114 , a timing control unit 113 , a data driving unit 112 , a gate driving unit 111 and a display panel ( 110) may be included.

The image processing unit 115 outputs the RGB data signal RGB after performing various image processing such as setting a gamma voltage to realize the maximum luminance according to the average image level using the RGB data signal RGB. The image processing unit 115 receives a driving signal including at least one of a vertical synchronization signal Vsync, a horizontal synchronization signal Hsync, a data enable signal DES, and a clock signal CLK as well as an RGB data signal RGB. print out

The timing controller 113 receives one or more of the vertical synchronization signal Vsync, the horizontal synchronization signal Hsync, the data enable signal DES, and the clock signal CLK from the image processing unit 115 or the data conversion unit 114 . is supplied with a driving signal including The timing controller 113 includes a gate timing control signal GCS for controlling the operation timing of the gate driver 111 and a data timing control signal DCS for controlling the operation timing of the data driver 112 based on the driving signal. to output

The timing controller 113 outputs the data signal DATA in response to the gate timing control signal GCS and the data timing control signal DCS.

The data driver 112 samples and latches the data signal DATA supplied from the timing controller 113 in response to the data timing control signal DCS supplied from the timing controller 113 and converts it into a gamma reference voltage. to output The data driver 112 outputs the converted data signal DATA through the data lines DL1 to DLn. The data driver 112 is formed in the form of an integrated circuit (IC).

The gate driver 111 outputs a gate signal while shifting the level of the gate voltage in response to the gate timing control signal GCS supplied from the timing controller 113 . The gate driver 111 outputs a gate signal through the gate lines GL1 to GLm. The gate driver 111 is formed in the form of an IC or is formed in the display panel 150 in a gate-in-panel (GIP) manner.

The display panel 110 may be implemented in a sub-pixel structure including, for example, a red sub-pixel SPr, a green sub-pixel SPg, and a blue sub-pixel SPb. That is, one pixel P is composed of RGB sub-pixels SPr, SPg, and SPb. However, the present invention is not limited thereto, and a white sub-pixel may be included.

4 is an exemplary diagram illustrating a circuit configuration of a sub-pixel of an organic light emitting display device.

In this case, a case in which the sub-pixel shown in FIG. 4 has a 2T (Transistor) 1C (Capacitor) structure including a switching transistor, a driving transistor, a capacitor, and an organic light emitting diode is exemplified. However, the present invention is not limited thereto, and when a compensation circuit is added, various configurations such as 3T1C, 4T2C, 5T2C may be provided.

Referring to FIG. 4 , in the organic light emitting display device, a gate line GL arranged in a first direction, a data line DL arranged spaced apart from each other in a second direction intersecting the first direction, and a driving power line VDDL ) defines a sub-pixel area.

One sub-pixel may include a switching transistor SW, a driving transistor DR, a capacitor Cst, a compensation circuit CC, and an organic light emitting diode (OLED).

The organic light emitting diode OLED operates to emit light according to a driving current formed by the driving transistor DR.

The switching transistor SW performs a switching operation so that the data signal supplied through the data line DL is stored as a data voltage in the capacitor Cst in response to the gate signal supplied through the gate line GL.

The driving transistor DR operates so that a driving current flows between the driving power line VDDL and the ground line GND according to the data voltage stored in the capacitor Cst.

The compensation circuit CC compensates for the threshold voltage of the driving transistor DR. The compensation circuit CC may include one or more transistors and a capacitor. Since the configuration of the compensation circuit CC is very diverse, detailed examples and descriptions thereof will be omitted.

As described above, the sub-pixel having the above configuration may be implemented as a front emission method, a back emission method, or a double-side emission method according to the structure.

5 is a cross-sectional view schematically illustrating the structure of an organic light emitting display device according to a first embodiment of the present invention.

6 is a cross-sectional view schematically showing another structure of the organic light emitting display device according to the first embodiment of the present invention.

7 is a cross-sectional view schematically showing the structure of one sub-pixel in the organic light emitting display device according to the first embodiment of the present invention shown in FIG. 5 . 7 illustrates an example of a blue sub-pixel of an organic light emitting display device using a thin film transistor having a coplanar structure. However, the present invention is not limited to the thin film transistor having a coplanar structure.

In this case, the organic light emitting display device illustrated in FIGS. 5 to 7 exemplifies a back light emission type organic light emitting display device in which light is emitted in the direction of the substrate on which the pixels are arranged. However, the present invention is not limited thereto, and may be applied to a top emission type organic light emitting display device in which light is emitted in the opposite direction to the substrate on which the pixels are arranged.

The organic light emitting diode display shown in FIGS. 5 to 7 exemplifies a white organic light emitting diode that emits white light using at least two organic light emitting layers. In this case, since the organic light emitting layer emits white light, red, green, and blue light A color filter is used to change the light of However, the present invention is not limited thereto, and the light emitting material included in the organic light emitting diode may be embodied in a manner in which the light emitting material is divided into RGB colors.

5 to 7 , the RGB sub-pixels SPr, SPg, and SPb may be implemented by using a white organic light emitting diode (OLED) and color filters R, G, and B.

The RGB sub-pixels SPr, SPg, and SPb include a transistor unit TFT, RGB color filters R, G, and B, and a white organic light emitting diode (OLED). In this case, when the white sub-pixel is provided, the white sub-pixel may include a transistor unit TFT and a white organic light emitting diode (OLED).

That is, the RGB sub-pixels SPr, SPg, and SPb include RGB color filters R, G, and B to convert white light emitted from the white organic light emitting diode (OLED) into red, green, and blue. . On the other hand, the white sub-pixel does not include a color filter because the white light emitted from the white organic light emitting diode (OLED) may be emitted as it is.

The method using RGB sub-pixels (SPr, SPg, SPb) is a method of depositing a white light emitting material on all sub-pixels, unlike the method of independently depositing red, green, and blue light emitting materials on each sub-pixel. For this reason, in this method, it is possible to increase the size without using a fine metal mask (FMM), to extend the lifespan and to reduce power consumption.

In particular, referring to FIG. 7 , one sub-pixel, for example, a blue sub-pixel, may include a transistor TFT, a white organic light emitting diode OLED, and a color filter B formed on the substrate 101 .

First, a thin film transistor driven by a transistor TFT includes a semiconductor layer 124 , a gate electrode 121 , a source electrode 122 , and a drain electrode 123 .

The semiconductor layer 124 is formed on the substrate 101 made of an insulating material such as a transparent plastic or a polymer film.

The semiconductor layer 124 may be formed of an amorphous silicon film, a polycrystalline silicon film obtained by crystallizing amorphous silicon, or an oxide semiconductor.

In this case, a buffer layer (not shown) may be further formed between the substrate 101 and the semiconductor layer 124 . The buffer layer may be formed to protect the transistor TFT formed in a subsequent process from impurities such as alkali ions leaking from the substrate 101 .

A gate insulating film 115a made of a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) is formed on the semiconductor layer 124 , and the gate line (not shown) including the gate electrode 121 and the first A sustain electrode (not shown) is formed.

The gate electrode 121, the gate line, and the first storage electrode are formed of a first metal material having a low resistance property, for example, aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), or gold (Au). ), titanium (Ti), nickel (Ni), neodymium (Nd), or an alloy thereof may be formed as a single layer or multiple layers.

On the gate electrode 121, the gate line and the first storage electrode, an inter insulation layer 115b made of a silicon nitride film or a silicon oxide film is formed, and a data line (not shown) and a driving voltage line ( (not shown), source/drain electrodes 122 and 123, and a second storage electrode (not shown) are formed.

The source electrode 122 and the drain electrode 123 are formed to be spaced apart from each other by a predetermined interval, and are electrically connected to the semiconductor layer 124 . More specifically, semiconductor layer contact holes exposing the semiconductor layer 124 are formed in the gate insulating layer 115a and the interlayer insulating layer 115b, and the source/drain electrodes 122 and 123 are connected through the semiconductor layer contact hole. It is electrically connected to the semiconductor layer 124 .

In this case, the second storage electrode overlaps a portion of the lower first storage electrode with the interlayer insulating layer 115b interposed therebetween to form a storage capacitor.

The data line, the driving voltage line, the source/drain electrodes 122 and 123 and the second storage electrode are formed of a second metal material having a low resistance property, for example, aluminum (Al), copper (Cu), molybdenum (Mo), It may be formed as a single layer or multiple layers made of chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), or an alloy thereof.

A passivation layer (or planarization layer) 115c is formed on the substrate 101 on which the data line, the driving voltage line, the source/drain electrodes 122 and 123 and the second storage electrode are formed.

Referring again to FIGS. 5 to 7 , color filters R, G, and B are formed on the passivation layer 115c. The color filters R, G, and B are color conversion materials that convert white light emitted from a white organic light emitting diode (OLED) into red, green, and blue.

An overcoat layer 115d covering the color filters R, G, and B and exposing a portion of the drain electrode 123 is formed on the passivation layer 115c. The overcoat layer 115d may be formed of an organic material, but may also be formed of an inorganic material or an organic-inorganic mixture.

The white organic light emitting diode OLED may include first electrodes 118r, 118g, and 118b , an organic light emitting layer 130 , and a second electrode 128 .

The white organic light emitting diode (OLED) is electrically connected to the driving thin film transistor. More specifically, in the passivation layer 115c and the overcoat layer 115d formed on the driving thin film transistor, a drain contact hole exposing the drain electrode 123 of the driving thin film transistor is formed. The white organic light emitting diode OLED is electrically connected to the drain electrode 123 of the driving thin film transistor through a drain contact hole.

That is, the first electrodes 118r, 118g, and 118b are formed on the overcoat layer 115d and are electrically connected to the drain electrode 123 of the driving thin film transistor through a drain contact hole.

The first electrodes 118r, 118g, and 118b supply current (or voltage) to the organic light emitting layer 130 and define a light emitting region of a predetermined area.

In addition, the first electrodes 118r, 118g, and 118b serve as an anode. Accordingly, the first electrodes 118r, 118g, and 118b may include a material having a relatively large work function compared to the second electrode 128 . For example, the transparent conductive material may include indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). However, the present invention is not limited thereto.

The first electrodes 118r, 118g, and 118b may be substantially transflective and reflective. In this case, a very thin metal layer such as silver (Ag) or an alloy of silver (Ag) and magnesium (Mg) may be used as the first electrodes 118r, 118g, and 118b.

At this time, in the case of the first embodiment of the present invention, a silicon nitride film (SiNx) 108a, 108b having a transmittance and refractive index similar to that of ITO in order to match a color viewing angle, color gamut and efficiency using a microcavity structure is used as the first electrode ( 118r, 118g, 118b) is laminated on the lower portion (in the case of FIG. 5) or the upper portion (in the case of FIG. 6) to form the optical compensation layers 108', 108", and 108'". When the optical compensation layers 108', 108", and 108'" are formed under the first electrodes 118r, 118g, and 118b, the drain contact hole is formed in the passivation layer 115c and the overcoat layer 115d as well as the optical compensation layer. (108', 108", 108'") is also exposed.

The light compensation layers 108', 108", and 108'" have a stacked structure of a first silicon nitride film 108a and a second silicon nitride film 108b.

The first silicon nitride layer 108a may be formed to be porous by sputtering or chemical vapor deposition, preferably sputtering.

A second silicon nitride film 108b is formed over the first silicon nitride film 108a. The second silicon nitride layer 108b may be formed to have a higher density than the first silicon nitride layer 108a by chemical vapor deposition.

The first silicon nitride layer 108a may be etched using dry etching, and the second silicon nitride layer 108b may be etched using wet etching.

Each of the first silicon nitride layer 108a and the second silicon nitride layer 108b may be formed to a thickness of 300 to 1000 Å.

The optical compensation layers 108', 108", and 108'" have a structure in which the first silicon nitride film 108a and the second silicon nitride film 108b are alternately stacked.

The optical compensation layers 108', 108", and 108'" include a first optical compensation layer 108' and a first silicon nitride layer 108a in which a first silicon nitride layer 108a and a second silicon nitride layer 108b are stacked once. ) and a second optical compensation layer 108" in which the second silicon nitride film 108b is stacked twice, and a third optical compensation layer ( 108'").

The first optical compensation layer 108', the second optical compensation layer 108" and the third optical compensation layer 108'" are respectively a blue sub-pixel SPb, a green sub-pixel SPg, and a red sub-pixel. - It may be positioned below or above the first electrodes 118r, 118g, and 118b of the pixel SPr. However, the present invention is not limited thereto.

The thickness of the second light compensation layer 108" is greater than that of the first light compensation layer 108', and the thickness of the third light compensation layer 108'" is the thickness of the second light compensation layer 108". thicker than the thickness

The light compensation layers 108', 108", 108'" together with the first electrodes 118r, 118g, 118b may be substantially transflective and reflective.

For example, the wavelength of light generated from the organic light emitting layer 130 is between the second electrode 128 and the first light compensation layer 108 ′ so that the luminance of the blue light of the blue sub-pixel SPb is increased by constructive interference. After reflecting back and forth in the , it passes through the blue color filter (B).

The wavelength of light generated from the organic light emitting layer 130 is reflected back and forth between the second electrode 128 and the second light compensation layer 108 ″ so that the luminance of the green light of the green sub-pixel SPg increases by constructive interference. After that, it passes through the green color filter (G).

The wavelength of light generated from the organic light emitting layer 130 moves back and forth between the second electrode 128 and the third light compensation layer 108 ″ so that the luminance of the red light of the red sub-pixel SPr increases by constructive interference. After reflection, it passes through a red color filter (R).

As such, between the second electrode 128 and the light compensation layer 108', 108", 108'", or between the second electrode 128 and the first electrode 118r, 118g, 118b, the organic light emitting layer 130 The light emitted from it will be reflected repeatedly. This reflected light is amplified or canceled by the relationship between the spatial distance between them and the wavelength of the reflected light. For example, in order to be amplified, the spatial distance where the reflection is repeated must be a multiple of the wavelength of the reflected light.

This phenomenon is called the micro-cavity effect and can be used to improve luminance efficiency.

In order to use the micro-cavity effect in the organic light emitting display device, each sub-pixel (SPr, SPg, SPb) has a resonant wavelength corresponding to the desired peak color wavelength for the sub-pixel (SPr, SPg, SPb). The microcavity depth or distance ( length) is formed.

The effective microcavity depth is defined by the optical distance, which is the wavelength. Since the wavelength of red light is longer than that of green light, the microcavity depth for the red sub-pixel SPr may be configured to be greater than the microcavity depth for the green sub-pixel SPg. In addition, since the wavelength of green light is longer than that of blue light, the microcavity depth for the green sub-pixel SPg may be configured to be greater than the microcavity depth for the blue sub-pixel SPb.

In this way, by forming the optical compensation layers 108', 108", 108'" having different thicknesses, that is, different transmittances and refractive indices for each sub-pixel (SPr, SPg, SPb), the color viewing angle, color gamut, and efficiency are improved. can be improved

In addition, the light compensation layers 108', 108", and 108'" according to the first embodiment of the present invention are formed by using a half-tone or multi-tone mask to form a sub-pixel (SPr). , SPg, SPb) can be formed in one mask process without patterning. Accordingly, the process is simplified and provides an effect of stabilization. When a white sub-pixel is added in addition to the red, green, and blue sub-pixels, a multi-tone mask may be used.

In addition, the optical compensation layers 108', 108", and 108'" are formed by successively depositing the first silicon nitride layer 108a and the second silicon nitride layer 108b to improve flatness. Accordingly, it provides an effect that step coverage is improved.

That is, in the conventional organic light emitting display device, when implementing a micro-cavity structure, a difference in light refractive index for each sub-pixel is used to compensate for a color viewing angle, color gamut, and efficiency. In order to minimize interference for each wavelength band, separate patterning is applied to each sub-pixel. Accordingly, there is a disadvantage in that the number of masks and the number of processes increase accordingly.

In order to improve this, in the present invention, a first silicon nitride film 108a and a second silicon nitride film 108b having different characteristics are successively formed by using a silicon nitride film having characteristics similar to ITO in addition to ITO, which is a driving electrode material of an organic light emitting diode. alternately deposited.

In this case, the high-density second silicon nitride film 108b may serve as a buffer layer that separates the optical compensation layers 108', 108", and 108'". Thereafter, through patterning, the optical compensation layers 108', 108", 108'" having the optimal transmission level are formed for each sub-pixel (SPr, SPg, SPb). In this case, in order to reduce the number of masks, half-tone Or use a multi-tone mask.

A bank 115e is formed on the substrate 101 on which the optical compensation layers 108', 108", and 108'" and the first electrodes 118r, 118g, and 118b are formed. In this case, the bank 115e defines an opening by enclosing the edges of the first electrodes 118r, 118g, and 118b like a weir, and is made of an organic insulating material.

The three sub-pixels SPr, SPg, and SPb are separated by a bank 115e.

The bank 115e may also be made of a photosensitive material including a black pigment, in which case the bank 115e serves as a light blocking member.

The organic emission layer 130 and the second electrode 128 are sequentially formed on the substrate 101 on which the bank 115e is formed.

That is, the organic emission layer 130 is formed between the first electrodes 118r, 118g, and 118b and the second electrode 128 . The organic emission layer 130 emits light by combining holes supplied from the first electrodes 118r, 118g, and 118b with electrons supplied from the second electrode 128 .

The organic light emitting layer 130 may have a multilayer structure including an auxiliary layer for improving the luminous efficiency of the light emitting layer in addition to the light emitting layer emitting light.

The organic emission layer 130 may be formed as a single layer connected to all pixels. In this case, it is preferable to include an organic light emitting material emitting white light. In this case, color filters R, G, and B may be formed for each sub-pixel SPr, SPg, and SPb to express various colors.

As another example, the organic emission layer 130 may be formed separately for each sub-pixel SPr, SPg, and SPb. In particular, in this case, each sub-pixel (SPr, SPg, SPb) may include an organic light emitting material emitting light of any one color among red, green, and blue.

The second electrode 128 is formed on the organic emission layer 130 to provide electrons to the organic emission layer 130 .

The second electrode 128 may be formed to cover the entire substrate 101 . That is, the first electrodes 118r, 118g, and 118b have a shape divided for each sub-pixel SPr, SPg, and SPb, but the second electrode 128 may be formed as a single layer connected across all the pixels. can

The second electrode 128 may be substantially reflective.

Hereinafter, a method of manufacturing the organic light emitting display device according to the first embodiment of the present invention as described above will be described in detail with reference to the drawings.

8A to 8I are cross-sectional views sequentially illustrating a method of manufacturing the organic light emitting display device according to the first embodiment of the present invention shown in FIG. 5 .

As shown in FIG. 8A , a substrate 101 made of an insulating material such as a transparent glass material or a transparent plastic or polymer film having excellent flexibility is prepared.

In addition, although not shown, a transistor and a storage capacitor are formed in each of the red, green, and blue sub-pixels of the substrate 101 .

First, a buffer layer is formed on the substrate 101 .

In this case, the buffer layer may be formed to protect the transistor from impurities such as alkali ions leaking from the substrate 101 , and may be formed of a silicon oxide layer.

Next, a semiconductor thin film is formed on the substrate 101 on which the buffer layer is formed.

The semiconductor thin film may be formed of amorphous silicon, polycrystalline silicon, or an oxide semiconductor.

In this case, polycrystalline silicon may be formed by depositing amorphous silicon on the substrate 101 and then using various crystallization methods, and when an oxide semiconductor is used as a semiconductor thin film, a predetermined heat treatment process may be performed after depositing the oxide semiconductor. .

Thereafter, a semiconductor layer made of a semiconductor thin film is formed by selectively removing the semiconductor thin film through a photolithography process.

Next, a gate insulating film and a first conductive film are formed on the substrate 101 on which the semiconductor layer is formed.

The first conductive layer may be formed of aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd) or A low-resistance opaque conductive material such as an alloy thereof may be used. However, they may have a multilayer structure comprising two conductive films having different physical properties. One conductive layer may be made of a metal having low resistivity, for example, an aluminum-based metal, a silver-based metal, or a copper-based metal, to reduce signal delay or voltage drop.

Thereafter, by selectively removing the first conductive layer through a photolithography process, a gate line including a gate electrode made of the first conductive layer and a first storage electrode are formed.

However, the present invention is not limited thereto, and the gate line including the semiconductor layer and the gate electrode and the first storage electrode may be formed through a single photolithography process.

Next, an interlayer insulating film made of a silicon nitride film or a silicon oxide film is formed on the entire surface of the substrate 101 on which the gate line including the gate electrode and the first storage electrode are formed.

Then, the semiconductor layer contact hole exposing the source/drain region of the semiconductor layer is formed by selectively patterning the interlayer insulating film through a photolithography process.

Next, a second conductive film is formed on the entire surface of the substrate 101 on which the interlayer insulating film is formed, and then the second conductive film is selectively removed through a photolithography process to thereby form data lines (i.e., source/drain electrodes, a driving voltage line, a data line, and a second storage electrode) are formed.

In this case, the second conductive layer is formed of aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), and neodymium (Nd) to form a data line. ) or a low-resistance opaque conductive material such as an alloy thereof may be used. However, they may have a multilayer structure comprising two conductive films having different physical properties. One conductive layer may be made of a metal having low resistivity, for example, an aluminum-based metal, a silver-based metal, or a copper-based metal, to reduce signal delay or voltage drop.

In this case, the source/drain electrodes are electrically connected to the source/drain regions of the semiconductor layer through the semiconductor layer contact hole, and the second storage electrode overlaps a portion of the first storage electrode with the interlayer insulating film interposed therebetween for storage. to form a capacitor.

Next, a protective film made of a silicon nitride film or a silicon oxide film is formed on the substrate 101 on which the source/drain electrodes, the driving voltage line, the data line, and the second storage electrode are formed.

In this case, a planarization layer made of an organic insulating material may be formed on the passivation layer, but the present invention is not limited thereto, and the passivation layer may serve as a planarization layer.

Then, a drain contact hole exposing the drain electrode is formed by selectively patterning the protective layer through a photolithography process.

Thereafter, color filters R, G, and B are formed on the substrate 101 on which the protective film is formed. The color filters R, G, and B are color conversion materials that convert white light emitted from the white organic light emitting diode into red, green, and blue.

Next, as shown in FIG. 8B , an overcoat layer 115d is formed on the entire surface of the substrate 101 on which the color filters R, G, and B are formed.

The overcoat layer 115d may be formed of an organic material, but may also be formed of an inorganic material or an organic-inorganic mixture.

Thereafter, a first silicon nitride film 108a and a second silicon nitride film 108b are alternately stacked on the overcoat layer 115d to form an optical compensation layer.

The first silicon nitride film 108a and the second silicon nitride film 108b have transmittance and refractive index similar to those of ITO.

The first silicon nitride layer 108a may be formed to have porosity by sputtering or chemical vapor deposition, preferably sputtering.

A second silicon nitride film 108b is formed over the first silicon nitride film 108a. The second silicon nitride layer 108b may be formed to have a higher density than the first silicon nitride layer 108a by chemical vapor deposition.

Each of the first silicon nitride layer 108a and the second silicon nitride layer 108b may be formed to a thickness of 300 to 1000 Å.

As described above, as the first silicon nitride film 108a and the second silicon nitride film 108b constituting the optical compensation layer are continuously deposited, the generation of foreign matter is reduced compared to the electrode. Further, the flatness is improved with successive deposition, resulting in improved step cover support.

At this time, although the case in which the first silicon nitride film 108a and the second silicon nitride film 108b are alternately deposited three times or a total of six times is illustrated in FIG. 8B , the present invention is not limited thereto. In addition, when a white sub-pixel is added, the first silicon nitride layer 108a and the second silicon nitride layer 108b may be deposited at least eight times.

Next, as shown in FIG. 8C , using a half-tone mask on the substrate 101 on which the second silicon nitride film 108b is formed, the first photoresist film pattern 170a of the first thickness and the first photoresist film pattern 170a having a first thickness and a second thickness greater than the first thickness are used. A second photoresist layer pattern 170b having a thickness of 2 is formed.

In this case, the first photoresist pattern 170a may be positioned to correspond to the green sub-pixel, and the second photoresist layer pattern 170b may be positioned to correspond to the red sub-pixel.

When a white sub-pixel is added, a third photoresist layer pattern having a third thickness is additionally formed using a multi-tone mask.

Next, as shown in FIG. 8D , a pair of first and second silicon nitride films 108a and second silicon nitride films of blue sub-pixels using the first photoresist pattern 170a and the second photoresist pattern 170b as masks 108b) is removed.

In this case, the first silicon nitride layer 108a may be etched using dry etching, and the second silicon nitride layer 108b may be etched using wet etching.

As a result, two pairs of first silicon nitride films 108a and second silicon nitride films 108b remain in the blue sub-pixel, while three pairs of first silicon nitride films 108a are left in the green sub-pixel and red sub-pixel. ) and the second silicon nitride film 108b remain.

Next, as shown in FIG. 8E , a third photoresist layer pattern 170b' having a third thickness is formed by removing a portion of the thickness of the second photoresist layer pattern while removing the first photoresist layer pattern through ashing. .

In this case, the third photoresist pattern 170b ′ may be positioned to correspond to the red sub-pixel.

Next, as shown in FIG. 8F , a pair of a first silicon nitride film 108a and a second silicon nitride film 108b of a blue sub-pixel and a green sub-pixel using the third photoresist film pattern 170b' as a mask. to remove

In this case, the first silicon nitride layer 108a may be etched using dry etching, and the second silicon nitride layer 108b may be etched using wet etching.

As a result, a pair of the first silicon nitride film 108a and the second silicon nitride film 108b remain in the blue sub-pixel, while the two pairs of the first silicon nitride film 108a and the second silicon film 108a are left in the green sub-pixel. The nitride film 108b remains, and three pairs of the first silicon nitride film 108a and the second silicon nitride film 108b remain in the red sub-pixel.

At this time, the first silicon nitride film 108a and the second silicon nitride film 108b are stacked once in the blue sub-pixel to constitute the first cavity layer 108'.

The first silicon nitride film 108a and the second silicon nitride film 108b are stacked twice in the green sub-pixel to constitute the second cavity layer 108". And the first silicon nitride film 108a in the red sub-pixel. ) and the second silicon nitride film 108b are stacked three times to form the third cavity layer 108'".

Accordingly, the thickness of the second cavity layer 108" is greater than the thickness of the first cavity layer 108', and the thickness of the third cavity layer 108'" is greater than the thickness of the second cavity layer 108". thick.

As described above, the cavity layers 108', 108", and 108'" have a stacked structure of the first silicon nitride film 108a and the second silicon nitride film 108b.

Next, as shown in FIG. 8G , a third conductive film is formed on the entire surface of the substrate 101 on which the cavity layers 108', 108", and 108'" are formed.

In this case, the third conductive layer may be made of a transparent conductive material such as ITO or IZO. However, the present invention is not limited thereto.

The third conductive layer may be substantially transflective and reflective. In this case, a very thin metal layer such as silver (Ag) or an alloy of silver (Ag) and magnesium (Mg) may be used as the third conductive layer.

Thereafter, the first electrodes 118r, 118g, and 118b made of the third conductive film are formed by selectively removing the third conductive film through a photolithography process.

Cavity layers 108', 108", 108'" may be substantially translucent and reflective with first electrodes 118r, 118g, 118b.

As such, the cavity layers 108', 108", and 108'" may be positioned under the first electrodes 118r, 118g, and 118b. However, the present invention is not limited thereto, and as described above, the cavity layers 108', 108", and 108'" may be positioned on the first electrodes 118r, 118g, and 118b.

Next, as shown in FIG. 8H , a bank 115e is formed on the substrate 101 on which the cavity layers 108', 108", 108'" and the first electrodes 118r, 118g, and 118b are formed. .

As described above, the bank 115e defines an opening by enclosing the edges of the first electrodes 118r, 118g, and 118b like a weir, and is made of an organic insulating material.

The three sub-pixels are separated by a bank 115e.

The bank 115e may also be made of a photosensitive material including a black pigment, and in this case, the bank 115e serves as a light blocking member.

Next, as shown in FIG. 8I , the organic light emitting layer 130 is formed on the substrate 101 on which the bank 115e is formed.

Although not shown in detail, for this purpose, a hole injection layer, a hole transport layer, a light emitting layer, and an electron transport layer are sequentially formed on the substrate 101 .

In this case, any one of the hole injection layer and the hole transport layer may be omitted.

An electron injection layer may be further formed on the electron transport layer to facilitate electron injection.

The organic emission layer 130 may be formed as a single layer connected to all pixels. In this case, it is preferable to include an organic light emitting material emitting white light. In this case, color filters R, G, and B may be formed for each sub-pixel to express various colors.

As another example, the organic emission layer 130 may be formed separately for each sub-pixel. In particular, in this case, each sub-pixel may include an organic light emitting material emitting light of any one color among red, green, and blue.

Thereafter, a second electrode 128 made of a fourth conductive layer is formed on the substrate 101 on which the organic light emitting layer 130 is formed.

The second electrode 128 is formed on the organic emission layer 130 to provide electrons to the organic emission layer 130 .

The second electrode 128 may be formed to cover the entire substrate 101 . That is, the first electrodes 118r, 118g, and 118b have a shape divided for each sub-pixel, but the second electrode 128 may be formed as a single layer connected across all the pixels.

The second electrode 128 may be substantially reflective.

The organic light emitting diode is sealed with a predetermined thin film encapsulation layer on the thus manufactured organic light emitting diode.

A polarization film may be provided on the upper surface of the thin film encapsulation layer to improve contrast by reducing reflection of external light of the organic light emitting display device. In this case, as the polarizing film, a circular polarizing film prepared by bonding multiple linear polarizing films or retardation films may be used.

Meanwhile, as described above, the present invention can be applied not only to the rear light emitting type but also to the front light emitting type organic light emitting display device, which will be described in detail through the second embodiment of the present invention.

9 is a cross-sectional view schematically illustrating a structure of an organic light emitting display device according to a second exemplary embodiment of the present invention.

And, FIG. 10 is a cross-sectional view schematically showing the structure of one sub-pixel in the organic light emitting display device according to the second embodiment of the present invention shown in FIG. 9 . 10 illustrates an example of a blue sub-pixel of an organic light emitting display device using a thin film transistor having a coplanar structure. However, the present invention is not limited to the thin film transistor having a coplanar structure.

In this case, the organic light emitting display device shown in FIGS. 9 and 10 exemplifies a top emission type organic light emitting display device in which light is emitted in the opposite direction to the substrate on which the pixels are arranged.

The organic light emitting display device shown in FIGS. 9 and 10 exemplifies the case in which the light emitting material included in the organic light emitting diode is formed by classifying RGB colors. However, the present invention is not limited thereto, and a white organic light emitting diode emitting white light using at least two organic light emitting layers may be used. In this case, since the organic light emitting layer emits white light, a color filter for changing into red, green, and blue light is used.

9 and 10 , the RGB sub-pixels SPr, SPg, and SPb include a transistor unit TFT and an organic light emitting diode (OLED).

That is, referring to FIG. 10 , one sub-pixel, for example, a blue sub-pixel, may include a transistor TFT and an organic light emitting diode OLED formed on a substrate 201 .

First, a thin film transistor driven by a transistor TFT includes a semiconductor layer 224 , a gate electrode 221 , a source electrode 222 , and a drain electrode 223 .

The semiconductor layer 224 is formed on the substrate 201 made of an insulating material such as a transparent plastic or a polymer film.

The semiconductor layer 224 may be formed of an amorphous silicon film, a polycrystalline silicon film obtained by crystallizing amorphous silicon, or an oxide semiconductor.

In this case, a buffer layer (not shown) may be further formed between the substrate 201 and the semiconductor layer 224 . The buffer layer may be formed to protect the transistor TFT formed in a subsequent process from impurities such as alkali ions leaking from the substrate 201 .

A gate insulating film 215a made of a silicon nitride film (SiNx) or a silicon oxide film (SiO ₂ ) is formed on the semiconductor layer 224 , and the gate line (not shown) including the gate electrode 221 and the first A sustain electrode (not shown) is formed.

The gate electrode 221 , the gate line, and the first storage electrode are formed of a first metal material having a low resistance, for example, aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), or gold (Au). ), titanium (Ti), nickel (Ni), neodymium (Nd), or an alloy thereof may be formed as a single layer or multiple layers.

On the gate electrode 221, the gate line, and the first storage electrode, an inter insulation layer 215b made of a silicon nitride film or a silicon oxide film is formed, and a data line (not shown) and a driving voltage line ( (not shown), source/drain electrodes 222 and 223, and a second storage electrode (not shown) are formed.

The source electrode 222 and the drain electrode 223 are formed to be spaced apart from each other by a predetermined interval, and are electrically connected to the semiconductor layer 224 . More specifically, semiconductor layer contact holes exposing the semiconductor layer 224 are formed in the gate insulating layer 215a and the interlayer insulating layer 215b, and the source/drain electrodes 222 and 223 are connected through the semiconductor layer contact hole. It is electrically connected to the semiconductor layer 224 .

In this case, the second storage electrode overlaps a portion of the lower first storage electrode with the interlayer insulating layer 215b interposed therebetween to form a storage capacitor.

The data line, the driving voltage line, the source/drain electrodes 222 and 223 and the second storage electrode are formed of a second metal material having a low resistance, for example, aluminum (Al), copper (Cu), molybdenum (Mo), It may be formed as a single layer or multiple layers made of chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), or an alloy thereof.

A passivation layer (or planarization layer) 215c is formed on the substrate 201 on which the data line, the driving voltage line, the source/drain electrodes 222 and 223 and the second storage electrode are formed.

Referring back to FIGS. 9 and 10 , an overcoat layer 215d exposing a portion of the drain electrode 223 is formed on the passivation layer 215c. The overcoat layer 215d may be formed of an organic material, but may also be formed of an inorganic material or an organic-inorganic mixture.

The overcoat layer 215d may be formed instead of the passivation layer 215c.

The organic light emitting diode (OLED) may include first electrodes 218r , 218g , and 218b , an organic light emitting layer 230 , and a second electrode 228 .

Such an organic light emitting diode (OLED) is electrically connected to the driving thin film transistor. More specifically, in the passivation layer 215c and the overcoat layer 215d formed on the driving thin film transistor, a drain contact hole exposing the drain electrode 223 of the driving thin film transistor is formed. The organic light emitting diode OLED is electrically connected to the drain electrode 223 of the driving thin film transistor through a drain contact hole.

That is, the first electrodes 218r, 218g, and 218b are formed on the overcoat layer 215d and are electrically connected to the drain electrode 223 of the driving thin film transistor through a drain contact hole.

The first electrodes 218r, 218g, and 218b supply current (or voltage) to the organic light emitting layer 230 and define a light emitting region of a predetermined area.

In addition, the first electrodes 218r, 218g, and 218b serve as an anode. Accordingly, the first electrodes 218r, 218g, and 218b may include a material having a relatively higher work function than that of the second electrode 228 . For example, the transparent conductive material may include indium-tin-oxide (ITO) or indium-zinc-oxide (IZO). However, the present invention is not limited thereto.

A bank 215e is formed on the substrate 201 on which the first electrodes 218r, 218g, and 218b are formed. In this case, the bank 215e defines an opening by enclosing the edges of the first electrodes 218r, 218g, and 218b like a weir, and is made of an organic insulating material.

The three sub-pixels SPr, SPg, and SPb are separated by a bank 215e.

The bank 215e may also be made of a photosensitive material including a black pigment, in which case the bank 215e serves as a light blocking member.

An organic light emitting layer 230, light compensation layers 208', 208", 208'", and a second electrode 228 are sequentially formed on the substrate 201 on which the bank 215e is formed.

At this time, in the case of the second embodiment of the present invention, silicon nitride (SiNx) films 208a and 208b having a transmittance and refractive index similar to ITO in order to match the color viewing angle, color gamut and efficiency using a micro-cavity structure are used as the second electrode ( 218) and the organic light emitting layer 230 to form the light compensation layers 208', 208", and 208'".

As described above, the optical compensation layers 208', 208", and 208'" have a stacked structure of the first silicon nitride film 208a and the second silicon nitride film 208b.

The first silicon nitride film 208a may be formed to have porosity by sputtering or chemical vapor deposition, preferably by sputtering.

A second silicon nitride film 208b is formed over the first silicon nitride film 208a. The second silicon nitride layer 208b may be formed to have a higher density than the first silicon nitride layer 208a by chemical vapor deposition.

The first silicon nitride layer 208a may be etched using dry etching, and the second silicon nitride layer 208b may be etched using wet etching.

Each of the first silicon nitride layer 208a and the second silicon nitride layer 208b may be formed to a thickness of 300 to 1000 Å.

The optical compensation layers 208', 208", and 208'" have a structure in which the first silicon nitride film 208a and the second silicon nitride film 208b are alternately stacked.

The optical compensation layers 208', 208", and 208'" include a first optical compensation layer 208' and a first silicon nitride layer 208a in which a first silicon nitride layer 208a and a second silicon nitride layer 208b are stacked once. ) and a second optical compensation layer 208" in which the second silicon nitride film 208b is stacked twice, and a third optical compensation layer 208 in which the first silicon nitride film 208a and the second silicon nitride film 208b are stacked three times. 208'").

The first optical compensation layer 208', the second optical compensation layer 208" and the third optical compensation layer 208'" are respectively a blue sub-pixel (SPb), a green sub-pixel (SPg) and a red sub-pixel. - It may be located under the second electrode 218 of the pixel SPr. However, the present invention is not limited thereto.

The thickness of the second light compensation layer 208" is greater than the thickness of the first light compensation layer 208', and the thickness of the third light compensation layer 208'" is that of the second light compensation layer 208". thicker than the thickness

The light compensation layers 208 ′, 208 ″, 208 ′″ together with the second electrode 218 may be substantially transflective and reflective.

As described above, light generated from the organic light emitting layer 230 is repeatedly reflected between the second electrode 228 and the first electrodes 218r, 218g, and 218b. This reflected light is amplified or canceled by the relationship between the spatial distance between them and the wavelength of the reflected light.

As described above, by forming the optical compensation layers 208', 208", and 208'" having different thicknesses, that is, different transmittances and refractive indices for each sub-pixel (SPr, SPg, SPb), the color viewing angle and color gamut and efficiency can be improved.

In addition, the light compensation layers 208', 208", 208'" according to the second embodiment of the present invention use a half-tone or multi-tone mask without patterning for each sub-pixel (SPr, SPg, SPb). It can be formed in one mask process. Accordingly, the process is simplified and provides an effect of stabilization. When a white sub-pixel is added in addition to the red, green, and blue sub-pixels, a multi-tone mask may be used.

In addition, the optical compensation layers 208', 208", and 208'" are formed by successively depositing the first silicon nitride film 208a and the second silicon nitride film 208b to improve flatness. Therefore, it provides the effect that the step cover support is improved.

The organic emission layer 230 is formed between the first electrodes 218r, 218g, and 218b and the second electrode 228 . The organic emission layer 230 emits light by combining holes supplied from the first electrodes 218r, 218g, and 218b with electrons supplied from the second electrode 228 .

The organic light emitting layer 230 may have a multilayer structure including an auxiliary layer for improving luminous efficiency of the light emitting layer in addition to the light emitting layer emitting light.

The organic emission layer 230 may be formed as a single layer connected to all pixels. In this case, it is preferable to include an organic light emitting material emitting white light. In this case, color filters may be formed for each sub-pixel (SPr, SPg, SPb) to express various colors.

As another example, the organic emission layer 230 may be formed separately for each sub-pixel SPr, SPg, and SPb. In particular, in this case, each sub-pixel (SPr, SPg, SPb) may include an organic light emitting material emitting light of any one color among red, green, and blue.

The second electrode 228 is formed on the organic emission layer 230 to provide electrons to the organic emission layer 230 .

The second electrode 228 may be formed to cover the entire substrate 201 . That is, the first electrodes 218r, 218g, and 218b have a shape divided for each sub-pixel SPr, SPg, and SPb, but the second electrode 228 may be formed as a single layer connected across all the pixels. can

The second electrode 228 may be substantially transflective and reflective.

Although many matters are specifically described in the above description, these should be construed as examples of preferred embodiments rather than limiting the scope of the invention. Accordingly, the invention should not be defined by the described embodiments, but should be defined by the claims and equivalents to the claims.

101,201: substrate
108a, 208a, 108b, 208b: silicon nitride film
108',208', 108",208", 108'",208'" : optical compensation layer
118r, 218r, 118g, 218g, 118b, 218b: first electrode
128,228: second electrode
130,230: organic light emitting layer

Claims (10)

a substrate in which red, green and blue sub-pixels are partitioned in a matrix form;
a first electrode disposed on each sub-pixel of the substrate;
an optical compensation layer disposed above or below the first electrode and having a stacked structure of a first silicon nitride layer and a second silicon nitride layer;
an organic light emitting layer disposed on the first electrode; and
and a second electrode disposed on the substrate on which the organic light emitting layer is disposed,
The optical compensation layer includes a first optical compensation layer, a second optical compensation layer and a third optical compensation layer respectively formed in the red, green and blue sub-pixels, the first optical compensation layer and the second optical compensation layer An organic light emitting display device, characterized in that the layer and the third light compensation layer have different thicknesses. The organic light emitting display device according to claim 1, further comprising red, green, and blue sub-color filters respectively disposed in the red, green, and blue sub-pixels. The organic light emitting display device according to claim 2, wherein the light compensation layer is positioned between the first electrode and the sub-color filter. The organic light emitting display device of claim 1 , wherein the light compensation layer is positioned between the second electrode and the organic light emitting layer. The organic light emitting display device of claim 1 , wherein the first silicon nitride layer is porous, and the second silicon nitride layer has a density higher than that of the first silicon nitride layer. The method of claim 1,
The first light compensation layer disposed in the blue sub-pixel is formed by stacking the first silicon nitride film and the second silicon nitride film,
The second light compensation layer disposed in the green sub-pixel is formed by stacking the first silicon nitride film, the second silicon nitride film, the first silicon nitride film, and the second silicon nitride film,
The third light compensation layer disposed in the red sub-pixel includes the first silicon nitride film, the second silicon nitride film, the first silicon nitride film, the second silicon nitride film, the first silicon nitride film and the second silicon nitride film. An organic light emitting display device, characterized in that it is formed by stacking. providing a substrate in which red, green and blue sub-pixels are partitioned in a matrix form;
forming a first electrode in each sub-pixel of the substrate;
forming an optical compensation layer having a stacked structure of a first silicon nitride film and a second silicon nitride film on an upper or lower portion of the first electrode;
forming an organic light emitting layer on the first electrode; and
and forming a second electrode on the substrate on which the organic light emitting layer is formed,
The method of claim 1, wherein the light compensation layer has different thicknesses for each of the red, green, and blue sub-pixels. The method of claim 7, wherein the forming of the light compensation layer comprises:
alternately stacking a first silicon nitride film and a second silicon nitride film on the substrate at least three times or more;
forming a first photoresist film pattern having a first thickness and a second photoresist film pattern having a second thickness on the substrate on which the first silicon nitride film and the second silicon nitride film are formed using a half-tone mask;
removing the pair of first and second silicon nitride films of the blue sub-pixel using the first photoresist pattern and the second photoresist pattern as masks;
forming a third photoresist film pattern having a third thickness while removing the first photoresist film pattern through ashing; and
and removing the pair of first and second silicon nitride films of the blue sub-pixel and the green sub-pixel using the third photoresist pattern as a mask. . The method of claim 8 , wherein the first silicon nitride layer is removed using dry etching, and the second silicon nitride layer is removed using wet etching. 9. The method of claim 8, wherein a pair of the first silicon nitride film and the second silicon nitride film remain in the blue sub-pixel to form a first optical compensation layer, and the two pairs of the first silicon nitride film are formed in the green sub-pixel. and a second silicon nitride layer remain to form a second optical compensation layer, and three pairs of the first silicon nitride layer and the second silicon nitride layer remain in the red sub-pixel to form a third optical compensation layer A method of manufacturing an electroluminescent display device.

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