KR20150137204A - Organic Electro-Luminescence Device - Google Patents

Abstract

Disclosed is an organic electroluminescence device. The disclosed organic electroluminescence device of the present invention comprises: a substrate on which a plurality of pixel areas of red (R), green (G), blue (B), and white (W) are divided; a driving thin film transistor formed on the pixel areas of the substrate, and color filters of red (R), green (G), blue (B), and white (W); an organic light emitting diode connected to the driving thin film transistor formed on each pixel area, and arranged on the color filters of red (R), green (G), blue (B), and white (W); and a low reflective film arranged between the substrate and the organic emitting diode in at least any one pixel area from the pixel areas of red (R), green (G), blue (B), and white (W).

Description

[0002] Organic Electro-Luminescence Device [0003]

The present invention relates to an organic electroluminescent device.

Until recently, CRT (cathode ray tube) was mainly used as a display device. However, in recent years, flat panel displays such as a plasma display panel (PDP), a liquid crystal display device (LCD), and an organic electro-luminescence device (OLED) Display devices have been widely studied and used.

Of the above flat panel display devices, an organic electroluminescent element (hereinafter referred to as OLED) is a self-luminous element and can be lightweight and thin because it does not require a backlight used in a liquid crystal display device which is a non-light emitting element.

Compared with liquid crystal display, it has superior viewing angle and contrast ratio, is advantageous in terms of power consumption, can be driven by DC low voltage, has a fast response speed, is strong against external impacts and has a wide temperature range Lt; / RTI >

Particularly, since the manufacturing process is simple, it is advantageous in that the production cost can be saved more than the conventional liquid crystal display device. OLEDs having such characteristics are largely divided into a passive matrix type and an active matrix type. In the passive matrix type, an element is formed in a matrix form while crossing signal lines, whereas the active matrix type is a pixel A thin film transistor which is a switching element for on / off switching, a driving thin film transistor for flowing a current, and a capacitor for holding a voltage for one frame in a driving thin film transistor are provided for each pixel.

In addition, the organic light emitting diode of each pixel is formed in the OLED. The organic light emitting diode includes an anode, a cathode, and an organic light emitting layer.

When the organic light emitting diode is applied with a voltage between the anode and the cathode, holes are injected from the anode into the organic light emitting layer, and electrons are injected from the cathode into the organic light emitting layer. The holes and electrons injected into the organic light emitting layer are combined in the organic light emitting layer to generate an exciton, and the exciton emits light while transitioning from the excited state to the ground state.

In recent years, passive matrix type has many limitations such as resolution, power consumption and lifetime, and active matrix type OLED capable of realizing high resolution and large screen is actively being studied.

In particular, a technique has been developed to attach a polarizing plate on a substrate to improve the screen quality of the OLED, thereby preventing external light from being reflected in the substrate area or being totally reflected within the substrate.

However, the technique of attaching the polarizer to the entire surface of the OLED has the effect of reducing the reflectance by absorbing the external light, but the light emitted from the organic light emitting layer of the organic light emitting diode absorbs the light emitted to the outside of the substrate, there is a problem.

A low reflection film is formed only on red (R), green (G), blue (B) and white (W) pixels or white (W) pixels of an organic electroluminescent device, And an organic electroluminescent device.

Another object of the present invention is to provide an organic electroluminescent device in which a low reflection film is formed on a white (W) pixel of an organic electroluminescent device to prevent a luminance defect in a white (W) pixel region in a black mode implementation .

According to an aspect of the present invention, there is provided an organic electroluminescent device including a substrate having a plurality of red (R), green (G), blue (B), and white (W) pixel regions defined therein; (R), green (G), blue (B), and white (W) color filters formed in pixel regions on the substrate; An organic light emitting diode connected to the driving thin film transistor formed in each pixel region and disposed on the red (R), green (G), blue (B), and white (W) color filters; And a low reflection film disposed between the substrate and the organic light emitting diode in at least one pixel region of the red (R), green (G), blue (B), and white (W) pixel regions.

The organic electroluminescent device of the present invention may further include a first substrate on which a plurality of red (R), green (G), blue (B), and white (W) pixel regions are partitioned; A driving thin film transistor formed in pixel regions on the first substrate and an organic light emitting diode; A capping layer formed on the driving thin film transistor and the organic light emitting diode; A second substrate facing the first substrate; Green (G), blue (B), and white (B) colors formed on the second substrate to correspond to the plurality of red (R), green (G), blue (B) (W) color filters; And a low reflective film disposed between the capping layer of the first substrate and the second substrate in pixel regions of at least any one of the red (R), green (G), blue (B) and white (W) .

The organic electroluminescent device of the present invention can be formed by forming a low reflection film only on the red (R), green (G), blue (B) and white (W) pixels or white (W) pixels of an organic electroluminescent device, It is possible to prevent deterioration of the contrast ratio due to the use of the light emitting diode.

In addition, the organic electroluminescent device of the present invention has the effect of preventing the brightness deficiency in the white (W) pixel region when the black mode is realized by forming a low reflection film on the white (W) pixels of the organic electroluminescent device.

1 is a cross-sectional view illustrating the structure of an OLED according to a first embodiment of the present invention.
2 is a diagram illustrating a pixel structure of an OLED according to a first embodiment of the present invention.
3A and 3B are graphs showing refractive indexes and extinction coefficients of metals used in the low reflection film of the first embodiment of the present invention.
FIGS. 4A and 6B are diagrams comparing a comparative example and an embodiment of the present invention when the OLED is driven in black.
FIG. 7 is a graph showing light efficiency characteristics of an OLED according to the first embodiment of the present invention.
8A is a cross-sectional view illustrating the structure of an OLED according to a second embodiment of the present invention.
FIG. 8B is a view schematically showing the structure of the white (W) pixel region of FIG. 8A.
9A is a cross-sectional view illustrating the structure of an OLED according to a third embodiment of the present invention.
FIG. 9B is a view schematically showing the structure of the white (W) pixel region of FIG. 9A.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention, and the manner of achieving them, will be apparent from and elucidated with reference to the embodiments described hereinafter in conjunction with the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims.

The shapes, sizes, ratios, angles, numbers, and the like disclosed in the drawings for describing the embodiments of the present invention are illustrative, and thus the present invention is not limited thereto. Like reference numerals refer to like elements throughout the specification. In the following description, well-known functions or constructions are not described in detail since they would obscure the invention in unnecessary detail.

In the case where the word 'includes', 'having', 'done', etc. are used in this specification, other parts can be added unless '~ only' is used. Unless the context clearly dictates otherwise, including the plural unless the context clearly dictates otherwise.

In interpreting the constituent elements, it is construed to include the error range even if there is no separate description.

In the case of a description of the positional relationship, for example, if the positional relationship between two parts is described as 'on', 'on top', 'under', and 'next to' Or " direct " is not used, one or more other portions may be located between the two portions.

In the case of a description of a temporal relationship, for example, if a temporal posterior relationship is described by 'after', 'after', 'after', 'before', etc., 'May not be contiguous unless it is used.

The first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are used only to distinguish one component from another. Therefore, the first component mentioned below may be the second component within the technical spirit of the present invention.

It is to be understood that each of the features of the various embodiments of the present invention may be combined or combined with each other, partially or wholly, and technically various interlocking and driving are possible, and that the embodiments may be practiced independently of each other, It is possible.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the size and thickness of the device may be exaggerated for convenience. Like reference numerals designate like elements throughout the specification.

The OLED 100 is divided into a top emission type and a bottom emission type according to the transmission direction of the emitted light. The third embodiment of the present invention will be described with reference to FIG.

1 is a cross-sectional view illustrating the structure of an OLED according to a first embodiment of the present invention.

Referring to FIG. 1, the OLED 100 according to the first embodiment of the present invention includes a driving region DA and a bank 221 formed with a region where the driving thin film transistor 210 (DTr) The pixel region in which the non-pixel region NA, red R, green G, blue B and white W color filters 223a, 223b, 223c, and 223d are formed, (PA). In addition, the white color filter 223d does not have a separate color filter pattern. However, for convenience of description, the transparent organic film 120 formed in the white (W) pixel region is referred to as a white (W) color filter 223d ).

In the first embodiment of the present invention, a low reflection film 250 is formed in a region corresponding to the white (W) color filter 223d forming region, and the external light is reflected in the substrate 101 region to cause a luminance defect . The low reflectivity film 250 travels through the substrate 101 to the inside of the white color filter 223d and the region of the organic light emitting diode E to be reflected by the reflective electrode (second electrode 232) It is possible to prevent a problem causing defects.

1, a bottom emission OLED 100 according to the present invention includes a substrate 101 on which a driving thin film transistor 210 (DTr), a switching thin film transistor (not shown) and an organic light emitting diode E are formed, And a capping layer 140 formed for encapsulation facing the substrate 101. The capping layer 140 may be a flexible substrate such as plastic or a metal substrate.

Further, the substrate 10 is a transparent flexible substrate, and may be glass or plastic, but is not limited thereto.

Although not shown in the drawing, a moisture absorbent may be formed on the inner surface of the capping layer 140 to remove moisture permeated from the outside.

A driving thin film composed of a gate electrode 201, a gate insulating film 102, a channel layer 204, source and drain electrodes 207a and 207b and an etch stopper 205 is formed in the non-pixel area NA of the substrate 101, A transistor 210 (DTr) is formed in the light emitting region PA and a gate insulating film 102, a protective film 109, and red (R), green (G), blue (W) color filters 223a, 223b, 223c, and 223d are formed.

The channel layer 204 of the driving thin film transistor 210 may be formed of an oxide semiconductor including at least one of indium (In), zinc (Zn), gallium (Ga), or hafnium (Hf) As shown in FIG.

Although not shown, a buffer layer made of a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a multilayer thereof is formed between the gate electrode 201 and the substrate 101 of the driving thin film transistor 210 (DTr) As shown in FIG.

As described above, the driving thin film transistor 210 and the red (R), green (G), and blue (B) color filters 223a and 223b are formed on the substrate 101 of the non-pixel region NA and the light- 223b and 223c and the low reflection film 250 are formed on the substrate 101, the organic film 120 is formed on the entire surface of the substrate 101. [ In the white (W) pixel region, the transparent organic film 120 serves as a white (W) color filter 223d without a separate color filter.

The organic layer 120 serves as an overcoat layer that can alleviate the lower step, and may be a benzocyclobutene (BCB) layer, a polyimide layer, or a polyacrylate layer.

The bank layer 221 is patterned in the non-pixel area NA to partition the respective pixel regions on the organic film 120 and the organic film 120 corresponding to the light- An organic light emitting diode E composed of an anode 230, an organic light emitting layer 231 and a second electrode 232 is formed.

The first electrode 230 may be an anode electrode and may be formed by laminating at least one of ITO (Indium Tin Oxide), IZO (Indium Tin Oxide), and ITZO (Indium Tin Zinc Oxide) can do. The first electrode 230 is electrically connected to the drain electrode 207b of the driving TFT 210 by a contact hole formed in the organic layer 120. [

The organic light emitting layer 231 includes a hole injecting layer (HIL), a hole transporting layer (HTL), an emitter material layer (EML), an electron transporting layer (ETL) (EIL: Electron Injection Layer). The hole transport layer may further include an electron blocking layer (EBL), and the electron transport layer (ETL) may be formed using a low molecular material such as PBD, TAZ, Alq3, BAlq, TPBI or Bepp2 .

Since the emission color of the organic emission layer 231 varies according to the organic material, red (R), green (G), and blue (B) emission layers are formed for each pixel region to realize full color , And a white light emitting layer. In the embodiment of the present invention, the white organic light emitting layer 231 for generating white light will be mainly described.

The second electrode 232 may be a cathode electrode and may be formed of a metal film such as aluminum (Al) or silver (Ag) having high reflectance.

As described above, when the organic light emitting diode E is formed on the substrate 101, a capping layer 140 for encapsulation is formed on the entire surface of the substrate 101.

In the present invention, the external light is absorbed by the low reflection film 250 formed on the substrate 101 region, thereby reducing the amount of reflected light reflected on the substrate 101 region, .

Although the low reflection film is formed between the organic film 120 and the protective film 109 used as the overcoat layer, the present invention is not limited thereto. Therefore, a low reflection film 250 may be formed between the substrate 101 and the gate insulating film 102, and between the gate insulating film 102 and the protective film 109, depending on circumstances.

It is preferable that the low reflection film 250 use a metal having a refractive index n and a extinction coefficient k that are similar to each other. For example, chromium (Cr) or molybdenum (Mo) can be used. However, it is not limited to this, and metal materials such as aluminum (Al), silver (Ag), titanium (Ti), tantalum (Ta), tungsten (W), and copper (Cu)

In the first embodiment of the present invention, the low reflection film 250 is formed only in the white (W) pixel region. However, the present invention is not limited to this. Therefore, a low reflection film can be formed in both the red (R), green (G), and blue (B) pixel regions. The red (R), green (G), and blue (B) color filters 223a, 223b, and 223c are formed in the center of the red (R), green (G), and blue (B) As shown in Fig.

That is, the first electrode 230 and the red (R), green (G), and blue (B) color filters 223a, 223b, and 223c are formed around the red (R), green Reflective film between the color filters 223a, 223b and 223c or between the red (R), green (G) and blue (B) color filters 223a, 223b and 223c and the substrate 101 have.

The organic electroluminescent device of the present invention can be formed by forming a low reflection film only on the red (R), green (G), blue (B) and white (W) pixels or white (W) pixels of an organic electroluminescent device, It is possible to prevent the contrast ratio from being lowered.

FIG. 2 is a graph showing the pixel structure of the OLED according to the first embodiment of the present invention, and FIGS. 3A and 3B are graphs showing the refractive index and the extinction coefficient of the metal used in the low reflection film of the first embodiment of the present invention .

Referring to FIG. 2 together with FIG. 1, the substrate 101 of the OLED is divided into red (R), green (G), blue (B) and white (W) regions, Reflective film 250 is formed between the substrate 100 and the substrate 101. [

Referring to FIGS. 3A and 3B, it is preferable that the low reflection film 250 formed in the embodiment of the present invention is excellent in light absorptivity and can transmit light generated from the organic light emitting layer without loss of light.

First, since a metal having a large light absorption coefficient has a similar refractive index (n) and extinction coefficient (k) values, a metal having an n / k value of 1 or less is suitable for use as the low reflection film 250. Therefore, metals having a refractive index (n) and an extinction coefficient (k) ratio (n / k) of 0.3 to 1.2 are used as a low reflection film.

Since a metal having a high light absorptivity is relatively low in light transmittance, a metal having a high light absorptivity is preferably used as a low-reflectivity film in order to form a thin film in Angstroms (A) to secure a transmittance.

In general, in embodiments of the present invention, the thickness of the low reflection film 250 can be selectively formed in the range of 10 to 200 angstroms.

3A and 3B, it can be seen that the refractive index and extinction coefficient of chromium (Cr: n / k = 1.01) or molybdenum (Mo: n / k = 0.35) are similar to each other.

Therefore, chromium (Cr) or molybdenum (Mo) has a high light absorptivity in the visible light region because metals having similar refractive indices (n) and extinction coefficients (k) have high light absorptivity. Accordingly, the reflection of external light can be lowered and the emission efficiency of the organic light emitting layer can be increased.

However, since metals generally absorb light, chromium (Cr) or molybdenum (Mo) as well as other opaque metals may be used when adjusting the thickness to be formed. For example, if the material can be sputtered and etched, it can be used as a low reflection film.

As the refractive index (n) of the metal material increases, the transmittance increases and the wavelength of light becomes shorter. As the extinction coefficient (k) increases, the light absorption rate increases. Therefore, the refractive index (n) (N / k) is close to 1, the transmittance of the internal light generated in the organic light emitting layer can be increased while increasing the external light absorption rate.

As described above, when a metal having a large extinction coefficient (k) value and a small refractive index (n) value is used as a low reflection film, the external light absorption rate is excellent, while the internal light transmittance is low. The transmittance can be secured.

Also, the low reflection film 250 used in the embodiment of the present invention can be used for a micro cavity optical design.

Ny * (dy /? B)} = 1.85 to 3.15 (Equation 1)? Nx * (dx /? B) +?

(where n is the refractive index, x is the inorganic material, d is thickness, E is the first electrode, y is the organic luminescent layer, lambda b is the blue peak wavelength and 1.85 to 3.15 is twice the wavelength

That is, by adjusting the thickness of the inorganic material, the first electrode, and the organic light emitting layer, which are used as a low reflective film, based on the organic light emitting diode emitting blue wavelength light, a micro cavity optical design capable of increasing light efficiency can be achieved.

Here, if the transmittance until the formation of the organic light emitting diode satisfies the requirement of 80% or more and the thickness of the layers formed by the inorganic material such as metal is fixed, by controlling the thickness of the organic materials such as the organic light emitting layers, Cavity optical design can be done.

As shown in FIG. 2, the organic layer 120 serves as a white (W) color filter without a separate color filter pattern in the white W region. Therefore, when external light is incident through the substrate 101, light transmitted through the substrate 101 and the substrate 101 is reflected by the second electrode 232 of the organic light emitting diode E, and light is emitted.

Such reflection light appears in a gray form due to reflected light when a black luminance is realized, which causes a degradation of screen quality.

However, in the embodiment of the present invention, since the low reflection film 250 having a high light absorption rate is formed between the substrate 101 and the organic film 120, the amount of light reflected on the substrate 101 region can be reduced.

In addition, since the light transmitted through the low reflection film 250 is reflected by the second electrode 232 of the organic light emitting diode E and then absorbed by the low reflection film 250, Can be reduced.

 FIGS. 4A and 6B are diagrams comparing a comparative example and an embodiment of the present invention when the OLED is driven in black.

Referring to FIGS. 4A and 4B, as in Comparative Example 1, a polarizer was disposed to reduce reflected light generated in a substrate region by external light.

That is, a first electrode, an organic light emitting layer, a second electrode and a capping layer are formed on one surface of the substrate, and a polarizing plate is attached to the entire area of the other surface of the substrate to absorb external light.

In this Comparative Example 1, since light incident from the outside is mostly absorbed in the polarizing plate, there is an advantage that reflected light generated in the substrate region can be reduced.

However, since the polarizer absorbs light generated in the organic light emitting layer, the light emitting efficiency of the organic light emitting diode is lowered.

As shown in FIG. 4B, when black driving is performed on the OLED of Comparative Example 1, reflection light is small when a black luminance is realized, and a high quality black color is realized. However, the light generated for image display in the organic light emitting layer is also absorbed by the polarizing plate, resulting in a decrease in the light efficiency.

Referring to FIGS. 5A and 5B, when the polarizing plate is attached to the substrate of the organic electroluminescent device as described in FIGS. 4A and 4B, the reflected light generated from the substrate can be reduced. However, The polarizer was removed.

Therefore, in Comparative Example 2, although the luminous efficiency of the organic light emitting diode is improved, the reflected light generated from the substrate or the second electrode of the organic light emitting diode can not be removed by external light.

As shown in FIG. 5B, when the OLED of Comparative Example 2 is driven with black, gray color is realized by reflection light when black luminance is implemented. That is, the loss of light generated in the organic light emitting diode can be minimized, but the contrast ratio is lowered due to the reflected light when implementing the black luminance.

6A and 6B, when a low reflection film is formed on one surface of a substrate as in the embodiment of the present invention, since the external light is absorbed in the substrate area, the light amount of the reflected light in the substrate area can be reduced.

As shown in FIG. 6 (b), black color can be seen when the black luminance is realized. That is, it can be seen that the black color corresponding to that between Comparative Example 1 in which the polarizing plate is attached on the substrate and Comparative Example 2 in which the polarizing plate is completely removed is realized.

FIG. 7 is a graph showing light efficiency characteristics of an OLED according to the first embodiment of the present invention.

Referring to FIG. 7, in Comparative Examples 1 and 2 of FIGS. 4A and 5A and in the first embodiment of the present invention, the thickness of the low reflection film is 60 Å (Example 1 (a)), (Example 1 (b)).

The first embodiment (a) and the first embodiment (b) are different from the first embodiment in that a low reflection film is formed in the red (R), green (G), blue (B) and white (W) pixel regions of an organic electroluminescent device .

Comparative Example 1 is a case where a polarizing plate for light absorption is arranged on the back surface of the substrate of the organic electroluminescent device and the light efficiency Cd (red) in the red (R), green (G), blue (B) / A).

As described with reference to FIGS. 4A and 4B, the polarizing plate of Comparative Example 1 had a problem of reducing the reflectance of external light, but the luminous efficiency of the organic light emitting diode was lowered.

(R), green (G), blue (B), and white (W) pixel regions in comparison with Comparative Example 1. The polarizing plate of Comparative Example 2 was removed from the substrate of the organic electroluminescent device, , 238%, 238%, 231%, and 237%, respectively.

(R), green (G), blue (B), and white (W) pixels are formed in a thickness of 60 angstroms as the low reflection film formed on the organic electroluminescent device, as in Example 1 (a) And 212%, 212%, 144%, and 201%, respectively.

When the thickness of the low reflection film formed on the organic electroluminescent device is set to 100 angstroms, the red (R), green (G), blue (B), and white ) Pixel area, the light efficiency is 183%, 165%, 131%, and 158%, respectively.

That is, as in the embodiment of the present invention, when a low reflection film having a high light absorptance is used, if the thickness is in the range of 10 to 200 angstroms, the light efficiency characteristic is greatly improved while reducing reflected light as compared with Comparative Example 1 in which the polarizer is attached There is an effect that can be.

FIG. 8A is a cross-sectional view illustrating the structure of an OLED according to a second embodiment of the present invention, and FIG. 8B is a view schematically illustrating a structure of a white (W) pixel region of FIG. 8A.

Hereinafter, the same reference numerals as those in FIG. 1 denote the same components, and the description will focus on the portions different from the first embodiment of the present invention.

8A and 8B, the organic electroluminescent device 200 according to the second embodiment of the present invention includes a gate electrode 201, a gate insulating film 102, a channel A driving thin film transistor 210 composed of a layer 204, source and drain electrodes 207a and 207b and an etch stopper 205 is disposed on the substrate 101. A gate insulating layer 102, A protective film 109 and red (R), green (G), blue (B) and white (W) color filters 223a, 223b, 223c and 223d are respectively formed.

On the organic film 120 on the red (R), green (G), blue (B) and white (W) color filters 223a, 223b, 223c and 223d, the organic light emitting diodes (E) is formed.

The first low reflection film 251 is formed between the protective film 109 and the organic film 120 in the white color filter 223d region of the second embodiment of the present invention, A second low reflection film 350 is formed between the organic film 120 and the first electrode 230 corresponding to the first electrode 230.

The first and second low reflection films 251 and 350 may be made of the same materials as those of the first and second low reflection films 251 and 350, Different metals can be used.

The thickness of the first and second low reflection films 251 and 350 may be selected to be 10 to 200 angstroms and the thickness of the first and second low reflection films 251 and 350 may be different from each other. have.

Although the first low reflection film 251 is formed on the protective film 120 in the drawing, the present invention is not limited thereto. Therefore, the first low reflection film 251 may be formed between the substrate 101 and the gate insulation film 102, and between the gate insulation film 102 and the protection film 109, depending on circumstances.

Further, the second low reflection film 350 is formed between the first electrode 230 and the organic film 120, but the present invention is not limited thereto. Accordingly, the second low reflection film 350 may be formed between the gate insulating film 102 and the protective film 109 or between the protective film 109 and the organic film 120, as the case may be. At this time, the position of the first low reflection film 251 is formed below the second low reflection film 350.

For example, when the second low reflection film 350 is formed between the gate insulation film 102 and the protection film 109, the first low reflection film 251 is formed between the gate insulation film 102 and the substrate 101 The first low reflection film 251 is formed between the gate insulation film 102 and the protection film 109 when the second low reflection film 350 is formed between the protection film 109 and the organic film 120.

Although the first and second low reflection films 251 and 350 are formed in the white pixel region in the OLED 200 of FIG. 8A, as in the first embodiment of the present invention, And the second low reflection films 251 and 350 may be formed in the red (R), green (G), and blue (B) pixel regions as well.

Referring to FIG. 8B, a first low reflection film is formed between the substrate and the organic film, and a second low reflection film is formed between the organic film and the first electrode of the organic light emitting diode.

In the second embodiment of the present invention, the external light is sequentially absorbed by the first and second low reflection films, and the amount of reflected light generated in the substrate region and the region below the organic light emitting diode can be reduced.

Also, the external light travels to the organic light emitting diode region, and the light reflected from the second electrode of the organic light emitting diode is absorbed by the first and second low reflection films, thereby realizing high quality black color during black driving.

FIG. 9A is a cross-sectional view showing the structure of an OLED according to a third embodiment of the present invention, and FIG. 9B is a view schematically showing the structure of a white (W) pixel region in FIG. 9A.

In the third embodiment of the present invention, the top emission type organic electroluminescent device will be described as an example. The third embodiment of the present invention differs from the first and second embodiments of the present invention in that the same reference numerals as in the first and second embodiments are used.

For example, in the third embodiment of the present invention, a low reflection film is formed on the capping layer 540 and the reference numeral is 560. However, the material of the low reflection film, thickness, , It can be implemented in the same manner as the low reflection film described in the second embodiment.

9A and 9B, the OLED 300 according to the third embodiment of the present invention includes a driving region DA and a bank 321 in a region where the driving thin film transistor DTr is formed for convenience of description. The non-pixel region NA and the pixel region in which the organic light emitting diode E is disposed to emit light are defined as a light emitting region PA.

The top emission type organic electroluminescent device 300 according to the present invention includes a first substrate 401 on which a driving thin film transistor DTr and a switching thin film transistor DTr (not shown) and an organic light emitting diode E are formed And a color filter substrate which is adhered to the first substrate 401 while facing the first substrate 401.

A capping layer 540 for encapsulating the driving transistor DTr and the organic light emitting diode E is formed on the first substrate 401. The first substrate 401 may be a flexible substrate such as a plastic substrate or a metal substrate.

The color filter substrate includes a second substrate 400 made of a transparent flexible substrate or a metal substrate such as the first substrate 401 and a second substrate 400 formed on the second substrate 400. The organic light emitting diode Green (G), blue (B), and white (W) color filters 411a, 411b, 411c, and 411d and a planar layer 450 to correspond to the red (R), green

The white color filter 411d does not have a separate color filter pattern but uses the transparent flat layer 450 as the white color filter 411d.

A gate electrode 301, a gate insulating film 402, a channel layer 304, source and drain electrodes 307a and 307b, and an etch stopper 305 are formed in the non-pixel area NA of the first substrate 401. [ A gate insulating film 402, a protective film 409 and an organic film 420 are formed on the first substrate 401 in the light emitting region PA.

The organic layer 420 is formed in the entire region of the first substrate 401 including the non-pixel region NA and the emission region PA and the organic layer 420 corresponding to the light- An organic light emitting diode E composed of a first electrode 330, an organic light emitting layer 331 and a second electrode 332 is formed.

In the third embodiment of the present invention, the first electrode 330 includes a first transparent electrode 330a, a reflective electrode 330b, and a second transparent electrode 330b, as shown in FIG. 9b. (330c). The second electrode 332 is also opaque metal in the first embodiment of the present invention. In the third embodiment of the present invention, a metal made of a transparent conductive material such as the first electrode of the first embodiment is used.

The organic light emitting diode E is divided into red (R), green (G), blue (B) and white (W) pixel regions by a bank layer 321 formed on a non- .

The channel layer 304 of the driving thin film transistor 310 may be an oxide semiconductor including at least one of indium (In), zinc (Zn), gallium (Ga), or hafnium (Hf) As shown in FIG.

Although not shown in the drawing, a silicon oxide film, a silicon nitride film, a silicon oxynitride film, or a multilayer thereof may be formed before forming the gate electrode 301 of the driving thin film transistor 310 (DTr) on the first substrate 401 The buffer layer may be further formed on the entire surface of the first substrate 401.

As described above, when the driving thin film transistor 310 and the organic light emitting diode E are formed on the first substrate 401 of the non-pixel area NA and the light emitting area PA, A capping layer 540 is formed.

A low reflection film 560 is formed on the capping layer 540 of the first substrate 401 corresponding to the white (W) color filter 411d formed on the second substrate.

In the third embodiment of the present invention, external light is incident through the rear surface of the second substrate 400 of the color filter substrate, and the incident light passes through the white (W) color filter 411d It is absorbed by the corresponding low reflection film 560 and the amount of reflected light can be reduced.

Therefore, even in the third embodiment of the present invention, it is possible to prevent the brightness deficiency in the white (W) region when driving the black.

As described in the first embodiment of the present invention, the low reflection film 560 preferably uses a metal having a refractive index (n) and a extinction coefficient (k) that are similar to each other.

For example, chromium (Cr) or molybdenum (Mo) can be used. However, it is not limited to this, and metal materials such as aluminum (Al), silver (Ag), titanium (Ti), tantalum (Ta), tungsten (W) and copper (Cu)

The low reflection layer 560 may be formed between the second substrate 400 and the white color filter 411d or may be formed on the planarization layer 450.

Although the low reflectance film 560 is formed on the red (R), green (G) and blue (B) regions of the OLED 300, ) Pixel regions.

That is, the second substrate 400 has a first substrate (not shown) corresponding to the red (R), green (G), blue (B) and white (W) color filters 411a, 411b, 411c, 401 may be formed on the capping layer 540.

The low reflection film 560 is formed between the second substrate 400 and the red (R), green (G), blue (B) and white (W) color filters 411a, 411b, 411c and 411d Can be formed on the flat layer 450 corresponding to the red (R), green (G), blue (B) and white (W) color filters 411a, 411b, 411c and 411d.

9B, a third embodiment of the present invention includes an organic light emitting diode E comprising a first electrode 330, an organic light emitting layer 331, and a second electrode 332 on a first substrate 401, And a second substrate 400 on which a capping layer 540, a low reflection film 560 and a white color filter are formed on the organic light emitting diode E are sequentially stacked.

Therefore, when the external light is incident through the back surface of the second substrate 400, the light is absorbed by the low reflection film 560, and the amount of light reflected by the second substrate 400 can be reduced.

100: OLED 101: substrate
102: gate insulating film 109: protective film
120: organic film 221: bank layer
140: capping layer 201: gate electrode
204: channel layer E: organic light emitting diode

Claims (15)

A substrate on which a plurality of red (R), green (G), blue (B), and white (W) pixel regions are partitioned;
(R), green (G), blue (B), and white (W) color filters formed on pixel regions of the substrate;
An organic light emitting diode connected to the driving thin film transistor formed in each pixel region and disposed on the red (R), green (G), blue (B), and white (W) color filters; And
And a low reflection film disposed between the substrate and the organic light emitting diode in at least one pixel region of the red (R), green (G), blue (B), and white (W) pixel regions, device.
The organic electroluminescent device according to claim 1, wherein the white (W) color filter is an organic film disposed in the white (W) pixel region.
The organic electroluminescent device according to claim 2, wherein a low reflection film disposed in the white (W) pixel region is disposed between the organic film and the substrate.
The organic electroluminescent device of claim 1, wherein the low reflective layer comprises a first low reflective layer and a second low reflective layer formed on different layers in respective red (R), green (G), blue (B) ≪ / RTI >
The organic electroluminescent device according to claim 1, wherein the low reflection film is a material having a ratio (n / k) of a refractive index (n) to an extinction coefficient (k) of 0.3 to 1.2.
The organic electroluminescent device according to claim 1, wherein the low reflective layer has a thickness of 10 to 200 ANGSTROM.
The organic electroluminescent device according to claim 1, wherein the low reflection film is chromium (Cr) or molybdenum (Mo).
The organic electroluminescent device according to claim 1, wherein the organic light emitting layer of the organic light emitting diode is a white organic light emitting layer.
A first substrate on which a plurality of red (R), green (G), blue (B), and white (W) pixel regions are partitioned;
An organic light emitting diode (OLED) having a pixel region formed on the first substrate;
A capping layer formed on the driving thin film transistor and the organic light emitting diodes;
A second substrate facing the first substrate;
Green (G), blue (B), and white (B) colors formed on the second substrate to correspond to the plurality of red (R), green (G), blue (B) (W) color filters; And
A low reflection film disposed between the capping layer of the first substrate and the second substrate in at least one pixel region of the red (R), green (G), blue (B), and white (W) And an organic electroluminescent device.
10. The organic electroluminescent device according to claim 9, wherein the white color filter is a flat layer formed on the entire surface of the second substrate so as to cover the red (R), green (G), and blue (B) Light emitting element.
The organic electroluminescent device according to claim 10, wherein a low reflection film disposed in the white (W) pixel region is disposed between the flat film and the second substrate.
The organic electroluminescent device according to claim 9, wherein the low reflection film is a material having a ratio (n / k) of a refractive index (n) to an extinction coefficient (k) of 0.3 to 1.2.
10. The organic electroluminescent device according to claim 9, wherein the low reflective layer has a thickness of 10 to 200 ANGSTROM.
10. The organic electroluminescent device according to claim 9, wherein the low reflection film is Cr or molybdenum (Mo).
The organic electroluminescent device according to claim 9, wherein the organic light emitting layer of the organic light emitting diode is a white organic light emitting layer.

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