KR20170127954A - White organic light emitting display device applying micro cavity - Google Patents

Abstract

The present invention relates to a white organic light emitting display device applying a micro cavity structure which forms the micro cavity structure by differentially controlling the thickness of a first electrode for each RGB sub-pixel as well as applying a translucent electrode as a second electrode in the RGB sub-pixel and applying a transparent electrode in a white sub-pixel. According to the present invention, by applying the micro cavity structure to the white organic light emitting display device, the power consumption is reduced by improving the efficiency as well as realizing large-scale high resolution.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a white organic light emitting display device using a micro cavity structure,

BACKGROUND OF THE INVENTION 1. Field of the Invention [0002] The present invention relates to an organic light emitting display, and more particularly, to a white organic light emitting display using a micro cavity structure.

Recently, interest in information display has increased, and as demand for portable information media has increased, research and commercialization of lightweight thin display devices have been focused on.

In such a display device field, a liquid crystal display device (LCD) is one of the remarkable display devices which is light and consumes less power.

The organic electroluminescent display device of the other display device is self-emission type and therefore has a better viewing angle and contrast ratio than the liquid crystal display device. In addition, since a backlight is not required, it is possible to make a light-weight thin type, and it is also advantageous in terms of power consumption. It has the advantage of being able to drive DC low voltage and has a fast response speed.

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

1 is a diagram for explaining the principle of light emission of a general organic light emitting diode.

An organic light emitting display generally includes an organic light emitting diode having a structure as shown in FIG.

1, an organic light emitting diode includes an anode 18 as a pixel electrode, a cathode 28 as a common electrode, and a plurality of organic layers 30a, 30b, 30c, 30d, and 30e ).

The organic layers 30a, 30b, 30c, 30d and 30e are formed of a hole transport layer (HTL) 30b, an electron transport layer (ETL) 30d, a hole transport layer 30b, And an emission layer (EML) 30c interposed between the emission layers 30d.

In this case, a hole injection layer (HIL) 30a is interposed between the anode 18 and the hole transport layer 30b to enhance the emission efficiency, and electrons are injected between the cathode 28 and the electron transport layer 30d. An electron injection layer (EIL) 30e is interposed.

When the positive and negative voltages are applied to the anode 18 and the cathode 28, the organic light emitting diode having the above structure passes through the hole transporting layer 30b and the electron transporting layer 30d One electron is moved to the light emitting layer 30c to form an exciton. When excitons are transited from an excited state to a ground state, that is, a stable state, light of a predetermined wavelength is generated.

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

At this time, the organic light emitting display device is divided into an active matrix method using a passive matrix or a thin film transistor as a switching element. The active matrix method selectively turns on the thin film transistor, which is an active element, to select a sub-pixel and maintain the emission of the sub-pixel with the voltage held in the storage capacitor.

In addition, the organic light emitting display device is divided into a RGB independent light emitting type, a method using a white OLED (hereinafter, referred to as WOLED) and an RGB color filter, and a color conversion method according to a method of implementing a full color . Of these, the RGB independent light emitting method has advantages of high efficiency and high color purity, but it is disadvantageous in that it is difficult to increase the area with a low resolution.

On the other hand, white organic light emitting display devices using WOLED and RGB color filters have a high resolution and are advantageous for a large-sized display by a simple process.

FIG. 2 is a cross-sectional view schematically illustrating the structure of a conventional white organic light emitting display device, which illustrates a white organic light emitting display device of a top emission type.

2, one pixel includes a red (R) sub-pixel, a green (G) sub-pixel, a blue (B) sub-pixel, and a white .

Though not shown, a switching transistor, a driving transistor and a capacitor are formed in each sub-pixel.

The reflection plate 18a and the anode 18b are formed in turn on the substrate (not shown) on which the switching transistor, the driving transistor and the capacitor are formed.

An organic layer 30 is formed on the anode 18b, and a cathode 28 made of a transparent conductive film is formed thereon.

On the substrate on which the cathode 28 is formed are sequentially provided a sealing layer 2 and a pressure sensitive adhesive layer 3 made of a resin on which the red sub-pixels on the green sub-pixel and the blue sub- A filter R, a green color filter G and a blue color filter B are formed.

At this time, the red color filter R, the green color filter G and the blue color filter B constitute the color filter layer 4, the white sub-pixel is applied to the white sub-color filter W, Sub-color filters may not be applied.

A cover glass 5 is provided on the color filter layer 4.

As described above, the white organic light emitting display device implements RGB sub-pixels by applying RGB color filters (R, G, B) to WOLED.

At this time, the white organic electroluminescent display device can not realize a micro cavity structure because a transparent conductive film must be applied to the cathode 28. Therefore, the white organic light emitting display device has a disadvantage that its efficiency and color purity are poor.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a white organic light emitting display having a micro cavity structure with high efficiency.

Other objects and features of the present invention will be described in the following description of the invention and the claims.

According to an aspect of the present invention, there is provided a white organic light emitting display including a first electrode having a different thickness for each RGB sub-pixel on a reflection plate, And a second electrode formed on the organic layer, the semi-transparent electrode being provided in the RGB sub-pixel and the transparent electrode provided in the white sub-pixel.

At this time, the RGB color filters may be further included in the RGB sub-pixels.

The thickness of the first electrode of the green sub-pixel is greater than the thickness of the first electrode of the blue sub-pixel, and the thickness of the first electrode of the red sub-pixel is greater than the thickness of the first electrode of the green sub- It may be thicker.

When the RGB sub-pixels and the white sub-pixels having the same color in the vertical direction are arranged on the display panel, the transparent electrodes and the translucent electrodes are arranged on the white sub-pixel region and the RGB sub- Lt; RTI ID = 0.0 > stripe < / RTI >

The semitransparent electrodes formed in the RGB sub-pixels may constitute a micro-cavity structure together with the first electrodes having different thicknesses formed therebelow.

In addition, the transparent electrode according to another embodiment of the present invention may be provided in the RGB sub-pixel.

In this case, when the RGB sub-pixels and the white sub-pixels of the same color are vertically arranged on the display panel, the transparent electrodes are provided over the entire display panel, while the semi- And may have a long stripe shape in the vertical direction only in the pixel region.

As described above, the white organic light emitting display device according to an embodiment of the present invention can realize a high-resolution large area by applying a micro-cavity structure to a white organic light emitting display device, and at the same time, Lt; / RTI >

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a diagram for explaining a principle of light emission of a general organic light emitting diode. FIG.
2 is a cross-sectional view schematically showing the structure of a general white organic light emitting display device.
3 is a block diagram schematically showing a white organic light emitting display device according to the present invention.
4 is an exemplary diagram showing a circuit configuration for a sub-pixel of a white organic light emitting display device.
5 is a cross-sectional view illustrating a white organic light emitting display device according to a first embodiment of the present invention.
FIG. 6 is a view illustrating a structure of a WRGB sub-pixel in a white organic light emitting display according to a first embodiment of the present invention shown in FIG. 5; FIG.
FIG. 7 is a cross-sectional view schematically illustrating one sub-pixel structure in a white organic light emitting display according to a first embodiment of the present invention shown in FIG. 5;
8 is a cross-sectional view schematically showing a structure of a white organic light emitting display device according to a first embodiment of the present invention.
FIG. 9 is a view illustrating a structure of an organic light emitting diode in a white organic light emitting display according to a first embodiment of the present invention. FIG.
FIGS. 10A to 10C are graphs showing light intensities according to wavelengths. FIG.
11A to 11E are sectional views sequentially illustrating a method of manufacturing a white organic light emitting display device according to a first embodiment of the present invention shown in FIG.
12 is a cross-sectional view illustrating a white organic light emitting display device according to a second embodiment of the present invention.
13 is a cross-sectional view schematically showing a structure of a white organic light emitting display device according to a second embodiment of the present invention.

Hereinafter, exemplary embodiments of the white organic light emitting display according to the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily carry out the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. It should be understood, however, that the invention is not limited to the disclosed embodiments, but is capable of many different forms and should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, To fully disclose the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. Like reference numerals refer to like elements throughout the specification. The dimensions and relative sizes of the layers and regions in the figures may be exaggerated for clarity of illustration.

It will be understood that when an element or layer is referred to as being another element or "on" or "on ", it includes both intervening layers or other elements in the middle, do. On the other hand, when a device is referred to as "directly on" or "directly above ", it does not intervene another device or layer in the middle.

The terms spatially relative, "below," "lower," "above," "upper," and the like, And may be used to easily describe the correlation with other elements or components. Spatially relative terms should be understood to include, in addition to the directions shown in the drawings, terms that include the different directions of the elements in use, or in operation. For example, when inverting an element shown in the figures, an element described as "below" or "beneath" of another element may be placed "above" another element. Thus, the exemplary term "below" can include both downward and upward directions.

The terminology used herein is for the purpose of describing embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. &Quot; comprise "and / or" comprising ", as used in the specification, means that the presence of stated elements, Or additions.

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

3, a white organic light emitting display 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, (110) may be included.

The image processing unit 115 performs various image processing such as setting a gamma voltage to realize the maximum luminance according to the average image level using the RGB data signals RGB, and then outputs RGB data signals RGB. The image processor 115 generates a driving signal including at least one of the RGB data signal RGB as well as the vertical synchronizing signal Vsync, the horizontal synchronizing signal Hsync, the data enable signal DES and the clock signal CLK Output.

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 And is supplied with a drive signal. The timing control section 113 generates a gate timing control signal GCS for controlling the operation timing of the gate driving section 111 and a data timing control signal DCS for controlling the operation timing of the data driving section 112, .

The timing controller 113 outputs the data signal DATA corresponding 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 outputs it. 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 IC (Integrated Circuit).

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

The display panel 110 is implemented with a sub-pixel structure including, for example, a red sub-pixel SPr, a green sub-pixel SPg, a blue sub-pixel SPb and a white sub- . That is, one pixel P may be composed of RGB sub-pixels SPr, SPg, SPb and a white sub-pixel SPw.

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

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

4, the white organic light emitting display includes a gate line GL arranged in a first direction and a data line DL arranged in a second direction crossing the first direction and a driving power line VDDL) define a sub-pixel region.

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 in accordance with the driving current generated by the driving transistor DR.

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

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

The compensation circuit CC compensates the threshold voltage of the driving transistor DR and the like. The compensation circuit CC may consist of one or more transistors and capacitors. The configuration of the compensation circuit (CC) is very various, and a detailed illustration and description thereof are omitted.

As described above, the sub-pixel having the above-described structure can be realized as a top emission type, a backside emission type, or a both-side emission type according to the structure.

Also, according to the method of implementing full-color, it is divided into RGB independent light emission method, a method using WOLED and RGB color filter, and a color conversion method.

The white organic light emitting display device according to the present invention has a high resolution by realizing a full-color using WOLED and RGB color filters, and has an advantage of being large in size with a simple process.

FIG. 5 is a cross-sectional view illustrating a white organic light emitting display according to an exemplary embodiment of the present invention. Referring to FIG.

FIG. 6 is a view illustrating a structure of a WRGB sub-pixel in a white organic light emitting display according to a first embodiment of the present invention shown in FIG.

FIG. 7 is a cross-sectional view schematically illustrating the structure of one sub-pixel in the white organic light emitting display according to the first embodiment of the present invention shown in FIG. Here, FIG. 7 shows an R sub-pixel of a white organic light emitting display using a coplanar structure thin film transistor as an example. However, the present invention is not limited to a thin film transistor having a coplanar structure.

FIG. 8 is a cross-sectional view schematically showing the structure of a white organic light emitting display device according to the first embodiment of the present invention, and schematically shows one pixel structure composed of WRGB sub-pixels.

5 to 8 illustrate a white organic light emitting display device of a top emission type in which light is emitted in a direction opposite to that of a substrate on which pixels are arranged. However, the present invention is not limited thereto, and may be applied to a white organic light emitting display device of a back light emission type in which light is emitted in the direction of a substrate on which pixels are arranged.

5 to 8 illustrate a WOLED that emits white light using at least two organic light emitting layers. In this case, since the organic light emitting layer emits white light, the red, green, and blue light Lt; / RTI > may be used.

5 to 8, the WRGB sub-pixels SPr, SPg, SPb, SPw may be implemented using a white organic light emitting diode WOLED and color filters R, G, B, have. At this time, a white color filter W may be applied to the white sub-pixel SPw or no color filter may be applied.

The RGB sub-pixels SPr, SPg and SPb include a transistor TFT, RGB color filters R, G and B and a white organic light emitting diode WOLED. And, when no color filter is applied to the white sub-pixel SPw, the white sub-pixel SPw may include a transistor TFT and a white organic light emitting diode WOLED.

That is, the RGB sub-pixels SPr, SPg, and SPb include RGB color filters R, G, and B to convert the white light emitted from the white organic light emitting diode WOLED into red, green, do. On the other hand, the white sub-pixel SPw may emit white light emitted from the white organic light emitting diode WOLED as it is, and thus may not include any color filter.

7, the structure of one sub-pixel, for example, the red sub-pixel SPr will be described in detail. The red sub-pixel SPr includes a transistor TFT formed on the substrate 101 , A white organic light emitting diode (WOLED), and a red color filter (R).

The thin film transistor may comprise a semiconductor layer 124, a gate electrode 121, a source electrode 122, and a drain electrode 123 as a transistor (TFT).

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

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

At this time, a buffer layer (not shown) may be additionally provided between the substrate 101 and the semiconductor layer 124. The buffer layer may be formed to protect a transistor (TFT) formed in a subsequent process from an impurity such as alkali ions flowing out from the substrate 101. [

A semiconductor layer (not shown), gate lines including a silicon nitride film (SiNx) or silicon oxide (SiO ₂₎ gate insulating film (115a), and can be formed and the gate electrode 121 on top made of, such as above 124 and a 1 sustain electrodes (not shown) may be formed.

The gate electrode 121 and the gate line and the first sustain electrode may be formed of a first metal material having low resistance characteristics such as aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr) (Au), titanium (Ti), nickel (Ni), neodymium (Nd), or alloys thereof.

An inter insulation layer 115b made of a silicon nitride film, a silicon oxide film or the like may be formed on the gate electrode 121 and the gate line and the first sustain electrode. A data line (not shown) A line (not shown), source / drain electrodes 122 and 123, and a second sustain electrode (not shown) may be formed.

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

At this time, the second sustain electrode overlaps a part of the first sustain electrode below the interlayer insulating film 115b to form a storage capacitor.

The data line, the driving voltage line, the source / drain electrodes 122 and 123 and the second sustain electrode may be formed of a second metal material having low resistance characteristics such as aluminum (Al), copper (Cu), molybdenum (Mo) And may be formed of a single layer or multiple layers of chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd)

A protective film (or a planarization film) 115c may be formed on the substrate 101 on which the data lines, the driving voltage lines, the source / drain electrodes 122 and 123, and the second sustain electrodes are formed.

Referring again to FIGS. 5 to 8, an overcoat layer 115d may be formed on the passivation layer 115c to expose a portion of the drain electrode 123. Referring to FIG. The overcoat layer 115d may be formed of an organic material, but may be formed of an inorganic material or a mixture of organic and inorganic materials.

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

This white organic light emitting diode (WOLED) is electrically connected to the driving thin film transistor. More specifically, the passivation layer 115c and the overcoat layer 115d formed on the driving thin film transistor may be formed with drain contact holes exposing the drain electrode 123 of the driving thin film transistor. The white organic light emitting diode WOLED may be electrically connected to the drain electrode 123 of the driving thin film transistor through the drain contact hole. However, the present invention is not limited thereto.

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

The first electrode 118b supplies a current (or voltage) to the organic layer 130, and defines a light emitting region having a predetermined area.

At this time, a reflection plate 118a is provided under the first electrode 118b, and the first electrodes 118b ', 118b' ', 118b' '' have different thicknesses for the RGB sub-pixels SPr, SPg, Lt; / RTI >

The reflection plate 118a is formed of a reflective material such as aluminum (Al), silver (Ag), or an alloy of silver and magnesium (Mg) so as to have the same thickness irrespective of the WRGB sub-pixels (SPr, SPg, SPb, .

The first electrode 118b (118b ', 118b' ', 118b' '') may include a material having a relatively large work function as an anode. Indium Tin Oxide (ITO) or Indium Zinc Oxide (IZO), which is a transparent conductive material, may be used as the first electrode 118b (118b ', 118b' . However, the present invention is not limited thereto.

In other words, the first electrodes 118b 118b ', 118b', 118b '' 'according to the first embodiment of the present invention are formed of RGB sub-pixels SPr, SPg, SPb for applying a micro- And have different thicknesses. In one example, the first electrode 118b 'of the red sub-pixel SPr may have a relatively thickest thickness and the first electrode 118b' of the blue sub-pixel SPb and the white sub- The thickness of the first electrode 118b "of the green sub-pixel SPg is greater than the thickness of the first electrode 118b '" of the blue sub-pixel SPb. The thickness of the first electrode 118b 'of the red sub-pixel SPr may be thicker than the thickness of the first electrode 118b "of the green sub-pixel SPg.

The first electrodes 118b 118b ', 118b', 118b '' 'may be formed using a fine metal mask (FMM) or may be formed by a single mask process using a multi-tone mask or the like. You may.

A bank 115e may be formed on the substrate 101 on which the reflection plate 118a and the first electrodes 118b 118b ', 118b' and 118b '' are formed. At this time, the bank 115e may be made of an organic insulating material to define an opening by surrounding the edges of the first electrode 118b (118b ', 118b', 118b '' ') like a dam.

The four sub-pixels SPr, SPg, SPb, SPw can be separated by the bank 115e.

The bank 115e may also be made of a photosensitizer containing a black pigment, in which case the bank 115e may serve as a light shielding member.

The organic layer 130 and the second electrodes 128a and 128b may be sequentially formed on the substrate 101 on which the banks 115e are formed.

The organic layer 130 may be formed between the first electrode 118b and the second electrodes 128a and 128b. The organic layer 130 may include a light emitting layer that emits light by a combination of holes supplied from the first electrode 118b and electrons supplied from the second electrodes 128a and 128b. That is, the organic layer 130 may have a multi-layer structure including an auxiliary layer for improving light emission efficiency of the light emitting layer in addition to the light emitting layer.

The organic layer 130 may be formed as one layer all connected over the entire pixels. In this case, it is preferable that the light emitting layer includes an organic luminescent material which generates white light. In this case, RGB color filters (R, G, B) may be provided for each of the RGB sub-pixels (SPr, SPg, SPb) However, the present invention is not limited thereto.

In this case, the organic layer 130 according to the first embodiment of the present invention can be applied to a blue color and a yellow-green (YG) two-peak element in the light emitting layer in order to generate white light, It is not.

FIG. 9 is a view illustrating an exemplary structure of an organic light emitting diode in a white organic light emitting display according to a first embodiment of the present invention. Referring to FIG.

Here, FIG. 9 shows an example of a white organic light emitting diode (WOLED) having a two-stack two-peak structure.

9, a white organic light emitting diode (WOLED) is disposed between a first electrode 118, a second electrode 128, a first electrode 118 and a second electrode 128, And a light emitting unit including a light emitting unit 131 and a second light emitting unit 132.

An N-type charge generation layer 135a and a P-type charge generation layer 135b may be disposed between the first light emitting portion 131 and the second light emitting portion 132. When two light emitting portions are formed as described above, the charge generating layers 135a and 135b control the balance of the charges between the first light emitting portion 131 and the second light emitting portion 132. [

At this time, the first light emitting portion 131 and the second light emitting portion 132 may be provided with a plurality of transporting layers and a buffer layer in order to improve efficiency and lifetime.

That is, the first light emitting portion 131 may include a first hole transporting layer 131b, a blue light emitting layer 131c, and a first electron transporting layer 131d.

The second light emitting portion 132 may include a second hole transporting layer 132b, a yellow-green emitting layer 132c, and a second electron transporting layer 132d.

The white organic light emitting diode (WOLED) emits white light using light of a blue peak and light of a yellow-green peak, and can pass the red, green, and blue color filters to realize a display.

Next, the second electrodes 128a and 128b may be formed on the organic layer 130 as a cathode to provide electrons to the organic layer 130. [

In this case, the second electrodes 128a and 128b according to the first embodiment of the present invention may have different electrode structures made of different materials for the white sub-pixel SPw and the RGB sub-pixels SPr, SPg and SPb .

That is, the second electrodes 128a and 128b according to the first embodiment of the present invention include a transparent electrode 128a formed in a white sub-pixel SPw and a translucent electrode 128a formed in the RGB sub-pixels SPr, SPg, (128b). The transparent electrode 128a and the semi-transparent electrode 128b may be formed using FMM, or may be formed using a photolithography process.

The transparent electrode 128a formed in the white sub-pixel SPw may be made of a metal material having a transmittance of 70% or more such as ITO or IZO.

The semitransparent electrode 128b formed in the RGB sub-pixels SPr, SPg, SPb may be made of a metal material having a transmittance of 30% or more and less than 60% such as MgAg.

When the WRGB sub-pixels SPr, SPg, SPb and SPw of the same color are arranged on the display panel in the vertical direction, the transparent electrode 128a and the semitransparent electrode 128b are connected to the white sub- And the RGB sub-pixels SPr, SPg, and SPb. However, the present invention is not limited thereto.

The semitransparent electrode 128b formed in the RGB sub-pixels SPr, SPg, SPb is formed with a first electrode 118b (118b ', 118b ", 118b'") Can be formed. As described above, according to the present invention, since the micro-cavity structure is applied to the white organic light emitting display, it is possible to realize a high-resolution large area, and at the same time, the power consumption is reduced by improving the efficiency.

For example, the light wavelength generated from the organic layer 130 is reflected back and forth between the second electrode 128b and the first electrode 118b so that the luminance of the blue light of the blue sub-pixel SPb is increased by constructive interference And then passes through the blue color filter (B).

The light wavelength generated from the organic layer 130 is reflected back and forth between the second electrode 128b and the first electrode 118b so that the luminance of the green light of the green sub-pixel SPg is increased by the constructive interference, Passes through the color filter (G).

The light wavelength generated from the organic layer 130 is reflected back and forth between the second electrode 128b and the first electrode 118b so that the luminance of the red light of the red sub-pixel SPr is increased by the constructive interference, Passes through the color filter (R).

In this way, light generated from the organic layer 130 repeats reflection between the second electrode 128b and the first electrode 118b. This reflected light is amplified or canceled by the relationship between the spatial distance therebetween and the wavelength of the reflected light. For example, in order to be amplified, the spatial distance at which the reflection is repeated should be a multiple of the wavelength of the reflected light.

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

FIGS. 10A to 10C are graphs showing light intensities according to wavelengths.

Here, FIG. 10A shows an example of light intensity according to wavelengths of the blue and yellow-green two-stack two-peak structure elements. FIG. 10B shows the light intensity according to the wavelength when the micro-cavity characteristic is given in a state in which the color filter is not formed. FIG. 10C shows the light intensity according to the wavelength in the case where the micro- The light intensity is shown as an example.

When the micro cavity effect is applied, the efficiency for red, green, and blue increases from 15.9, 6.2, and 79.6, respectively, to 6.2 (cd / A) and 2.7 to 3.3. In this case, the efficiencies for red, green and blue are increased by about 156%, 182% and 22%, respectively.

As a result, it can be seen that the power consumption is improved by about 45% from 6521 mW to 3603 mW, for example.

Next, the sealing layer 102 and the adhesive layer 103 are sequentially formed on the substrate 101 on which the second electrodes 128a and 128b are formed, and RGB color filters R, G, and B are formed thereon . The RGB color filters (R, G, and B) are color conversion materials that convert white light emitted from a white organic light emitting diode (WOLED) to red, green, and blue.

At this time, a red color filter R, a green color filter G and a blue color filter B are provided for the red sub-pixel SPr, the green sub-pixel SPg and the blue sub- .

The red color filter R, the green color filter G and the blue color filter B constitute the color filter layer 104 and the white sub-pixel SPw is applied to the white sub-color filter W No sub-color filter may be applied.

A cover glass 105 may be provided on the color filter layer 104.

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

FIGS. 11A to 11E are cross-sectional views sequentially illustrating a method of manufacturing a white organic light emitting display according to a first embodiment of the present invention shown in FIG.

Referring to FIG. 11A, a substrate 101 made of a transparent glass material or an insulating material such as a transparent plastic or a polymer film excellent in flexibility is prepared.

Although not shown, transistors and storage capacitors are formed in the red, green, blue, and white sub-pixels SPr, SPg, SPb, and SPw of the substrate 101, respectively.

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

At this time, the buffer layer may be formed to protect the transistor from impurities such as alkali ions flowing out from the substrate 101, and may be formed of a silicon oxide film.

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

Thereafter, the semiconductor thin film is selectively removed through a photolithography process to form a semiconductor layer made of a semiconductor thin film.

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

Thereafter, the first conductive film is selectively removed through the photolithography process, thereby forming the gate line including the gate electrode made of the first conductive film and the first sustain electrode.

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

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

Then, an interlayer insulating film is selectively patterned through a photolithography process to form a semiconductor layer contact hole exposing a source / drain region of the semiconductor layer.

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 form data lines (that is, source / drain electrodes, A driving voltage line, a data line, and a second sustain electrode).

At this time, the second conductive film may be formed of aluminum (Al), copper (Cu), molybdenum (Mo), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium ) Or their alloys may be used. However, they may have a multi-layer structure including two conductive films having different physical properties. One of the conductive films may be made of a metal having a low resistivity, for example, an aluminum-based metal, a silver-based metal, a copper-based metal, or the like so as to reduce signal delay or voltage drop.

At this time, the source / drain electrode is electrically connected to the source / drain region of the semiconductor layer through the semiconductor layer contact hole, and the second sustain electrode overlaps with a part of the first sustain electrode below the interlayer insulating film, Thereby forming a capacitor.

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

At this time, a planarizing film composed of an organic insulating material may be formed on the protective film, but the present invention is not limited thereto, and the protective film may serve as the planarizing film.

Then, a protective film is selectively patterned through a photolithography process to form a drain contact hole exposing the drain electrode.

Thereafter, an overcoat layer 115d is formed on the entire surface of the substrate 101 on which the protective film is formed.

The overcoat layer 115d may be formed of an organic material, but may be formed of an inorganic material or a mixture of organic and inorganic materials.

Next, a reflection plate 118a made of a third conductive film and first electrodes 118b ', 118b' ', 118b' '' made of a fourth conductive film are formed on the substrate 101. At this time, the first electrodes 118b ', 118b' 'and 118b' '' may have different thicknesses depending on the RGB sub-pixels SPr, SPg and SPb.

The reflection plate 118a is formed of a reflective material such as aluminum (Al), silver (Ag), or an alloy of silver and magnesium (such as aluminum) so as to have the same thickness irrespective of the WRGB sub-pixels (SPr, SPg, SPb, SPw) 3 conductive film).

The first electrode 118b ', 118b' ', 118b' '' may include a material having a relatively large work function. For example, the first electrodes 118b ', 118b' ', 118b' '' may be made of a transparent conductive material such as ITO or IZO (a fourth conductive film). However, the present invention is not limited thereto.

As described above, the first electrodes 118b ', 118b', 118b '' 'according to the first embodiment of the present invention are arranged in the order of RGB sub-pixels SPr, SPg and SPb for applying a high- And has a different thickness. In one example, the first electrode 118b 'of the red sub-pixel SPr may have a relatively thickest thickness and the first electrode 118b' of the blue sub-pixel SPb and the white sub- The thickness of the first electrode 118b "of the green sub-pixel SPg is greater than the thickness of the first electrode 118b '" of the blue sub-pixel SPb. The thickness of the first electrode 118b 'of the red sub-pixel SPr may be thicker than the thickness of the first electrode 118b "of the green sub-pixel SPg.

The first electrodes 118b ', 118b' ', 118b' '' may be formed using FMM, or may be formed by a single mask process using a multi-tone mask or the like.

Next, referring to FIG. 11B, a bank 115e is formed on the substrate 101 on which the first electrodes 118b ', 118b' ', 118b' '' are formed.

As described above, the bank 115e surrounds the edges of the first electrodes 118b ', 118b ", 118b' "like a bank to define openings and can be made of an organic insulating material.

The four sub-pixels SPr, SPg, SPb, SPw can be separated by the bank 115e.

The bank 115e may also be made of a photosensitizer containing a black pigment, in which case the bank 115e serves as a shielding member.

Next, referring to FIG. 11C, the organic layer 130 is formed on the substrate 101 on which the banks 115e are formed.

The organic layer 130 may be formed as one layer all connected over the entire pixels. In this case, it is preferable to include an organic luminescent material which generates white light. In this case, a color filter may be formed for each of the sub-pixels SPr, SPg, SPb, and SPw in order to express various colors.

Next, second electrodes 128a and 128b made of fifth and sixth conductive films are formed on the substrate 101 on which the organic layer 130 is formed.

In this case, the second electrodes 128a and 128b according to the first embodiment of the present invention are different materials (fifth and sixth) for the white sub-pixel SPw and the RGB sub-pixels SPr, SPg and SPb, A conductive film) is applied to the electrode.

That is, the second electrodes 128a and 128b according to the first embodiment of the present invention include the transparent electrodes 128a and the RGB sub-pixels SPr, SPg, and SPb formed of the fifth conductive film in the white sub- And a semi-transparent electrode 128b composed of a sixth conductive film. The transparent electrode 128a and the semi-transparent electrode 128b may be formed using FMM, or may be formed using a photolithography process.

The transparent electrode 128a formed in the white sub-pixel SPw may be made of a metal material (fifth conductive film) having a transmittance of 70% or more such as ITO or IZO.

The translucent electrode 128b formed in the RGB sub-pixels SPr, SPg, SPb may be made of a metal material (sixth conductive film) having a transmittance of 30% or more and less than 60% of MgAg or the like.

When the WRGB sub-pixels SPr, SPg, SPb and SPw of the same color are arranged on the display panel in the vertical direction, the transparent electrode 128a and the semitransparent electrode 128b are connected to the white sub- And the RGB sub-pixels SPr, SPg, and SPb. However, the present invention is not limited thereto.

The semitransparent electrode 128b formed in the RGB sub-pixels SPr, SPg, SPb forms a micro-cavity structure together with the first electrodes 118b ', 118b ", 118b" can do. As described above, according to the present invention, since the micro-cavity structure is applied to the white organic light emitting display, it is possible to realize a high-resolution large area, and at the same time, the power consumption is reduced by improving the efficiency.

A white organic light emitting diode (WOLED) may be sealed as a predetermined thin film sealing layer on the thus manufactured white organic light emitting diode (WOLED).

11D, the sealing layer 102 and the adhesive layer 103 are sequentially formed on the substrate 101 on which the second electrodes 128a and 128b are formed.

The adhesive layer 103 may be made of a resin.

Next, referring to FIG. 11E, a color filter layer 104 is formed on a substrate 101 on which an adhesive layer 103 is formed.

At this time, the color filter layer 104 includes a red sub-pixel SPr, a red color filter R formed in each of the green sub-pixel SPg and the blue sub-pixel SPb, And a blue color filter (B). In addition, the color filter layer 104 may further include a white sub-color filter W formed on the white sub-pixel SPw, but the present invention is not limited thereto, and the white sub- A sub-color filter may not be formed.

A cover glass may be provided on the color filter layer 104.

Meanwhile, the second electrode according to the present invention may be composed of a transparent electrode formed on the entire surface of the substrate and a translucent electrode formed on RGB sub-pixels on the transparent electrode, which will be described in detail in the following second embodiment of the present invention .

FIG. 12 is a cross-sectional view illustrating a white organic light emitting display according to a second embodiment of the present invention. Referring to FIG.

13 is a cross-sectional view schematically showing the structure of a white organic light emitting display device according to a second embodiment of the present invention, and schematically shows one pixel structure composed of WRGB sub-pixels.

12 and 13 illustrate a white organic light emitting display device of a top emission type in which light is emitted in a direction opposite to that of a substrate on which pixels are arranged. However, the present invention is not limited thereto, and may be applied to a white organic light emitting display device of a back light emission type in which light is emitted in the direction of a substrate on which pixels are arranged.

12 and 13 illustrate a WOLED 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 Lt; / RTI > may be used.

12 and 13, the WRGB sub-pixels SPr, SPg, SPb, and SPw may be implemented using a white organic light emitting diode WOLED and color filters R, G, B, have. At this time, a white color filter W may be applied to the white sub-pixel SPw or no color filter may be applied.

The RGB sub-pixels SPr, SPg and SPb include a transistor (not shown), RGB color filters (R, G, B) and a white organic light emitting diode WOLED. And, when no color filter is applied to the white sub-pixel SPw, the white sub-pixel SPw may include a transistor and a white organic light emitting diode WOLED.

That is, the RGB sub-pixels SPr, SPg, and SPb include RGB color filters R, G, and B to convert the white light emitted from the white organic light emitting diode WOLED into red, green, do. On the other hand, the white sub-pixel SPw may emit white light emitted from the white organic light emitting diode WOLED as it is, and thus may not include any color filter.

Though not shown in detail, the driving thin film transistor may comprise a semiconductor layer, a gate electrode, a source electrode, and a drain electrode.

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

The semiconductor layer may be composed of an amorphous silicon film, a polycrystalline silicon film obtained by crystallizing amorphous silicon, an oxide semiconductor or the like.

At this time, a buffer layer may be further provided between the substrate 201 and the semiconductor layer.

A gate insulating film made of a silicon nitride film (SiNx), a silicon oxide film (SiO2) or the like may be formed on the semiconductor layer, and a gate line and a first sustain electrode including a gate electrode may be formed thereon.

An interlayer insulating film made of a silicon nitride film, a silicon oxide film, or the like may be formed over the gate electrode, the gate line, and the first sustain electrode, and a data line, a driving voltage line, a source / drain electrode, have.

The source electrode and the drain electrode are spaced apart from each other by a predetermined distance, and may be electrically connected to the semiconductor layer. More specifically, the gate insulating film and the interlayer insulating film may be formed with a semiconductor layer contact hole exposing the semiconductor layer, and the source / drain electrode may be electrically connected to the semiconductor layer through the semiconductor layer contact hole.

At this time, the second sustain electrode overlaps with a part of the first sustain electrode below the interlayer insulating film to form a storage capacitor.

A protective film (or a flattening film) may be formed on the substrate 201 on which the data lines, the driving voltage lines, the source / drain electrodes and the second sustain electrodes are formed.

An overcoat layer 215d may be formed on the passivation layer to expose a part of the drain electrode. The overcoat layer 215d may be formed of an organic material, but may be formed of an inorganic material or a mixture of organic and inorganic materials.

The white organic light emitting diode WOLED may include a first electrode 218b and an organic layer 230 and second electrodes 228a and 228b.

This white organic light emitting diode (WOLED) is electrically connected to the driving thin film transistor. More specifically, the protective film and the overcoat layer 215d formed on the driving thin film transistor may have a drain contact hole exposing the drain electrode of the driving thin film transistor. The white organic light emitting diode WOLED may be electrically connected to the drain electrode of the driving thin film transistor through the drain contact hole. However, the present invention is not limited thereto.

The first electrode 218b supplies a current (or voltage) to the organic layer 230, and defines a light emitting region having a predetermined area.

The first electrode 218b, 218b ", and 218b '' are connected to the RGB sub-pixels SPr, SPg, SPb as an anode, and the first electrode 218b, They can have different thicknesses.

The reflection plate 218a is formed of a reflective material such as aluminum (Al), silver (Ag), or an alloy of silver and magnesium (Mg) so as to have the same thickness irrespective of the WRGB sub-pixels (SPr, SPg, SPb, .

The first electrode 218b (218b ', 218b' ', 218b' '') may include a material having a relatively large work function. For example, the first electrode 218b (218b ', 218b' ', 218b' '') may include ITO or IZO which is a transparent conductive material. However, the present invention is not limited thereto.

The first electrodes 218b ', 218b' 'and 218b' '' according to the second embodiment of the present invention are formed of RGB sub-pixels SPr, SPg and SPb for applying a high-efficiency micro- And have different thicknesses. In one example, the first electrode 218b 'of the red sub-pixel SPr may have a relatively thickest thickness and the first electrode 218b' of the blue sub-pixel SPb and the white sub- The thickness of the first electrode 218b "of the green sub-pixel SPg is equal to the thickness of the first electrode 218b '" of the blue sub-pixel SPb, The thickness of the first electrode 218b 'of the red sub-pixel SPr may be thicker than the thickness of the first electrode 218b "of the green sub-pixel SPg.

The first electrodes 218b (218b ', 218b', 218b '' ') may be formed using FMM, or may be formed by a single mask process using a multi-tone mask or the like.

A bank 215e may be formed on the substrate 201 on which the reflection plate 218a and the first electrodes 218b 218b ', 218b', and 218b '' are formed. At this time, the bank 215e may be made of an organic insulating material by surrounding the edges of the first electrodes 218b (218b ', 218b', 218b '' ') like a bank to define openings.

The four sub-pixels SPr, SPg, SPb, SPw can be separated by the bank 215e.

The bank 215e may also be made of a photoresist containing a black pigment, in which case the bank 215e may serve as a light shielding member.

The organic layer 230 and the second electrodes 228a and 228b may be sequentially formed on the substrate 201 on which the banks 215e are formed.

The organic layer 230 may be formed between the first electrode 218b and the second electrodes 228a and 228b. The organic layer 230 may include a light emitting layer that emits light by a combination of holes supplied from the first electrode 218b and electrons supplied from the second electrodes 228a and 228b. That is, the organic layer 230 may have a multi-layer structure including a sub-layer for improving the light-emitting efficiency of the light-emitting layer in addition to the light-emitting layer.

The organic layer 230 may be formed as one layer all connected over the entire pixels. In this case, it is preferable that the light emitting layer includes an organic luminescent material which generates white light. In this case, RGB color filters (R, G, B) may be provided for each of the RGB sub-pixels (SPr, SPg, SPb) However, the present invention is not limited thereto.

Next, the second electrodes 228a and 228b may be formed on the organic layer 230 as a cathode to provide electrons to the organic layer 230. [

The second electrodes 228a and 228b according to the second embodiment of the present invention are different from the first embodiment of the present invention in that the transparent electrodes 228a and 228b formed in the WRGB sub-pixels SPr, SPg, SPb, 228a and a translucent electrode 228b formed on the RGB sub-pixels SPr, SPg, SPb. The transparent electrode 228a and the semi-transparent electrode 228b may be formed using FMM, or may be formed by a single mask process using a half-tone mask or the like. When the mask is formed by a single mask process using a half-tone mask, the process can be simplified and the yield can be improved compared to the first embodiment of the present invention.

The transparent electrode 228a formed in the WRGB sub-pixels SPr, SPg, SPb, and SPw may be made of a metal material having a transmittance of 70% or more such as ITO or IZO.

The semitransparent electrode 228b formed in the RGB sub-pixels SPr, SPg, SPb may be made of a metal material having a transmittance of 30% or more and less than 60% such as MgAg.

In this case, when the WRGB sub-pixels SPr, SPg, SPb, and SPw of the same color are vertically arranged on the display panel, the transparent electrode 228a is formed over the entire display panel while the translucent electrode 228b, Pixels SPr, SPg, and SPb. However, the present invention is not limited thereto.

The semitransparent electrode 228b formed in the RGB sub-pixels SPr, SPg and SPb has a first electrode 218b, 218b ", and 218b " Can be formed. As described above, according to the present invention, since the micro-cavity structure is applied to the white organic light emitting display, it is possible to realize a high-resolution large area, and at the same time, the power consumption is reduced by improving the efficiency.

Next, the sealing layer 202 and the adhesive layer 203 are sequentially formed on the substrate 201 on which the second electrodes 228a and 228b are formed, and RGB color filters R, G, and B are formed thereon . The RGB color filters (R, G, and B) are color conversion materials that convert white light emitted from a white organic light emitting diode (WOLED) to red, green, and blue.

At this time, a red color filter R, a green color filter G and a blue color filter B are provided for the red sub-pixel SPr, the green sub-pixel SPg and the blue sub- .

The red color filter R, the green color filter G and the blue color filter B constitute the color filter layer 204 and the white sub-pixel SPw is applied to the white sub-color filter W No sub-color filter may be applied.

A cover glass 205 may be provided on the color filter layer 204.

While a great many are described in the foregoing description, it should be construed as an example of preferred embodiments rather than limiting the scope of the invention. Therefore, the invention should not be construed as limited to the embodiments described, but should be determined by equivalents to the appended claims and the claims.

101, 201: substrate 104, 204: color filter layer
118a, 218a: reflector 118b, 218b: first electrode
128a and 228a: transparent electrodes 128b and 228b: translucent electrodes
130, 230: organic layers R, G, B: color filters

Claims (9)

A substrate partitioned into an RGB sub-pixel and a white sub-pixel;
A reflector disposed in each of the sub-pixels of the substrate;
A first electrode having a different thickness for each RGB sub-pixel on the reflection plate;
An organic layer disposed on the first electrode; And
And a second electrode formed on the organic layer, the semi-transparent electrode being provided in the RGB sub-pixel and the transparent electrode provided in the white sub-pixel. The white organic light emitting display of claim 1, further comprising an RGB color filter disposed in each of the RGB sub-pixels. The method of claim 1, wherein the thickness of the first electrode of the green sub-pixel is greater than the thickness of the first electrode of the blue sub-pixel, and the thickness of the first electrode of the red sub- Wherein the thickness of the first electrode is greater than the thickness of the first electrode. The white organic light emitting display according to claim 1, wherein the translucent electrode comprises a metal material having a transmittance of 30% or more and less than 60%. The white organic light emitting display according to claim 1, wherein the transparent electrode comprises a metal material having a transmittance of 70% or more. The method of claim 1, wherein when the RGB sub-pixels and the white sub-pixels of the same color are arranged in the vertical direction on the display panel, the transparent electrodes and the translucent electrodes are connected to the white sub- - A white organic electroluminescent display device having a long stripe shape in the vertical direction with respect to the pixel region. The white organic light emitting display of claim 1, wherein the semitransparent electrode formed in the RGB sub-pixel comprises a micro-cavity structure together with the first electrode having a different thickness below the first electrode. The white organic light emitting display according to claim 1, wherein the transparent electrode is provided in the RGB sub-pixel. 9. The display device according to claim 8, wherein when the RGB sub-pixel and the white sub-pixel of the same color are vertically arranged on the display panel, the transparent electrode is provided over the entire display panel, Wherein the RGB sub-pixel region has a vertically long stripe shape only.

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