KR20040000629A - Organic electro luminescence display device and method of manufacturing the same - Google Patents

Abstract

PURPOSE: An organic light emitting display device and a fabricating method thereof are provided to increase the emitting efficiency of light by reducing the number of layers for transmitting the light radiated from an organic layer of a pixel region. CONSTITUTION: An organic light emitting display device includes a substrate(100), a first electrode layer(112), a buffer layer(121), a driving part forming layer, a planarization layer(129), an organic layer(114), a second electrode layer(116), and an optical loss prevention layer. The first electrode layer(112) is formed on the transparent substrate(100). The buffer layer(121) is formed on the transparent substrate(100). The buffer layer(121) includes a first opening portion to expose a part of the first electrode layer(112). The driving part forming layer is formed on the buffer layer(121). The driving part forming layer includes a TFT and a second opening portion. The planarization layer(129) is used for burying the driving part forming layer. The planarization layer(129) includes a third opening portion. The organic layer(114) is formed on an upper surface of the first electrode layer(112). The second electrode layer(116) is formed on the organic layer(114) and the planarization layer(129). The optical loss prevention layer is formed between the transparent substrate(100) and the first electrode layer(112) to prevent the loss of light radiated from the organic layer(114).

Description

Organic electroluminescent display device and method of manufacturing the same {Organic electro luminescence display device and method of manufacturing the same}

The present invention relates to an organic electroluminescent display, and more particularly, to an organic electroluminescent display having improved extraction efficiency of light generated by an organic layer.

In general, an organic light emitting display device is a self-luminous display that electrically excites fluorescent organic compounds and emits light, and can be driven at low voltage, is easy to thin, and is pointed out as a problem in liquid crystal display devices such as wide viewing angle and fast response speed. It is attracting attention as the next generation display that can solve the shortcomings.

In the organic light emitting diode display, an organic layer having a predetermined pattern is formed on glass or other transparent insulating substrate, and electrode layers are formed on upper and lower portions of the organic layer. The organic film consists of organic compounds. Materials for forming such organic films include phthalocyanine (CuPc: copper phthalocyanine), N, N-di (naphthalen-1-yl) -N, N'-diphenyl-benzidine (N, N'-Di (naphthalene-1) -yl) -N, N'-diphenyl-benzidine (NPB), tris-8-hydroxyquinoline aluminum (Alq3), etc. are used.

In the organic light emitting display device configured as described above, as the anode and cathode voltages are applied to the electrodes, holes injected from the electrode to which the anode voltage is applied are moved to the light emitting layer via the hole transport layer, and the electrons have a cathode voltage. It is injected from the applied electrode into the light emitting layer via the electron transport layer. In this light emitting layer, electrons and holes recombine to produce excitons, and as the excitons change from the excited state to the ground state, the fluorescent molecules in the light emitting layer emit light to form an image.

The light efficiency of the organic light emitting display device driven as described above is divided into internal efficiency and external efficiency. The internal efficiency depends on the photoelectric conversion efficiency of the organic light emitting material, The external efficiency, also called light coupling efficiency, is due to the refractive index of each layer constituting the organic light emitting display. Among them, the light extraction efficiency, which is an external efficiency, is lower than that of other display devices such as cathode ray tubes and PDPs, and thus, there is much room for improvement in characteristics of display devices such as brightness and lifetime.

As such, the biggest reason why the light extraction efficiency of the organic light emitting display device is lower than that of other display devices is that a layer having a high refractive index and a passivation film, such as an ITO electrode layer, is emitted when light emitted by the organic film is emitted above a critical angle. This is because total reflection occurs at the interface between the layers having a low refractive index, such as a substrate, and thus is prevented from being taken out to the outside, so that only about one quarter of the light generated in the organic light emitting layer can be used.

In the conventional organic electroluminescence display as shown in FIG. 1, light transmitted from the organic film 3 is transmitted through the glass substrate 1, which is a transparent substrate at the interface of the electrode 2 made of ITO. The efficiency is based on the equation 1/2 (N _out / N _in ) ² . Where N is the refractive index. Reference numeral 4 denotes another electrode different in polarity from the ITO electrode 2.

Based on the above formula, the light extraction rate for each color of the conventional organic light emitting display device is shown in the following table.

Blue organic film Green organic film Red organic film Wavelength (nm) 450 530 620 Refractive index of the ITO electrode (n) 2.01 1.93 1.76 Refractive index of glass substrate (n) 1.525 1.52 1.515 Light extraction rate 29% 34% 37%

As shown in the above table, it can be seen that due to the difference in refractive index between the ITO electrode and the glass substrate, a large amount of light is dissipated by 60% or more in the organic light emitting display.

An example of a conventional organic electroluminescent display for preventing such a decrease in light extraction rate is disclosed in Japanese Laid-Open Patent Publication No. 63-172691. The disclosed organic electroluminescent display includes a substrate having light condensation such as a protruding lens. However, such a convex lens for condensing is difficult to form on the substrate because the pixel according to the emission of the organic film is very small.

Japanese Laid-Open Patent Publication No. 62-172691 discloses an organic electroluminescent display with a first dielectric layer interposed between a transparent electrode layer and a light emitting layer and a second dielectric layer having a refractive index between the first dielectric layer and the transparent electrode on a transparent electrode side. Japanese Patent Laid-Open No. Hei 1-220394 discloses an apparatus, and an organic electroluminescent display in which a lower electrode, an insulating layer, a light emitting layer and an upper electrode are formed on a substrate, and a mirror is formed to reflect light on one surface of the light emitting layer. An apparatus is disclosed.

Since the organic light emitting display device has a very thin thickness of the light emitting layer, it is very difficult to install a mirror for reflection on the side surface, and as a result, the production cost increases.

In order to solve these problems, Japanese Laid-Open Patent Publication No. 11-283751 discloses an organic electroluminescent display device having one or more organic layers between an anode and a cathode, and includes a structure including a diffraction grating or a zone plate as a component. Is disclosed. This is to form a diffraction grating near the boundary where the refractive index is different and to extract the light of the organic layer by the light scattering effect.

2 shows a bottom emission type organic electroluminescent display device of an AM (Active Matrix) driving method to which a diffraction grating structure disclosed in Japanese Patent Laid-Open No. 11-283751 is applied.

In the AM organic light emitting display device, a buffer layer 11 is formed on a transparent substrate 10, and a p-type or n-type semiconductor layer 12 arranged in a predetermined pattern on the buffer layer 11 is gated. A gate electrode layer 14 corresponding to the semiconductor layer 12, a first insulating layer 15 filling the gate electrode layer 14, and a first insulating layer 15 buried by the insulating layer 13. Drain electrodes 16 formed on the first insulating layer 15 and connected to both sides of the semiconductor layer 12 through contact holes 16a and 17a formed in the gate insulating layer 13 and 15, respectively. A thin film transistor including a source electrode 17, a first auxiliary electrode 23b connected to the source electrode 17 and formed on an upper surface of the first insulating layer 15, and opposed to the first auxiliary electrode 23b. And a driving region formed of a capacitor 23 formed of a second auxiliary electrode 23a embedded in the first insulating film 15. A first insulating layer 18 formed on the upper surface of the upper surface 15, a planarization film 19 having the openings 19a formed therein, and a bottom surface of the opening of the planarization film 19 electrically connected to the drain electrode 16. An electrode layer 20 is formed, an organic layer 21 is stacked on the first electrode layer 20, and a second electrode layer 22 is formed on the organic layer and the planarization layer to form a pixel region.

In the bottom emission type organic light emitting display device as described above, the first electrode layer 20 is made of ITO, which is a transparent conductive material, and the substrate 10, the buffer layer 11, the gate insulating layer 13, and the first, The two insulating films 15 and 18 are also made of a transparent material. In this case, since the transparent first electrode layer 20 has a high refractive index and the second insulating layer 18 has a low refractive index, the protrusions 18a are formed at the interface thereof, as shown in a partially enlarged view. It has a function of a diffraction grating to increase the light extraction efficiency.

However, when the first electrode layer 20 is formed of ITO on the upper surface of the second insulating film 18 on which the protrusions 18a are formed as described above, the step of the second insulating film 18 forming the protrusions 18a is increased. As it is reflected in the first electrode layer 20 as shown in the figure, the protrusion 20a is formed in the first electrode layer 20. Therefore, the protrusion 20a of the first electrode layer 20 also affects the organic film layer 21 deposited as a thin thin film on the upper surface of the first electrode layer 20, and thus the protrusion 21a of the shape corresponding to the organic film layer. Is formed. However, since the thickness of the organic film layer 21 is very thin, the deposition thickness of the organic film may be thin in the vicinity of the side surface of the protrusion 21a, and as shown in the drawing, the protrusion of the first electrode layer 20 ( A portion S of which the side surface and the second electrode layer 22 are short-circuited at the side portion of the protrusion portion 21a of the organic film layer 21 is generated. In the organic light emitting display device having the above structure, it is very difficult to remove the protrusions of the first electrode layer 20 due to the other layers.

In the organic light emitting display device having the above structure, since the driving region including the TFT and the capacitor is formed and the pixel region including the electrode and the organic layer is formed, the light emitted from the organic layer 21 is removed. Since the first insulating film 15, the gate insulating film 13, the buffer layer 11, the lower substrate 10, and the like must pass through the boundary between the first electrode layer 20 and the second insulating film 18, the refractive index is high. It has to pass through the different layers again, and in this process, the light extraction efficiency gradually decreases.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-described problems, and provides an organic electroluminescent display device and a method of manufacturing the same, which can increase luminous efficiency by reducing the number of layers through which light emitted from an organic layer in a pixel region passes. The purpose is.

Another object of the present invention is to provide an organic light emitting display device and a method of manufacturing the same, which can increase the luminance of an image by reducing light loss therein to increase luminous efficiency.

Another object of the present invention is to planarize the upper surface of the first electrode layer more easily when the optical loss prevention layer of the diffraction grating is formed between the substrate and the first electrode layer to prevent a short circuit between the first electrode layer and the second electrode layer. An organic electroluminescent display and a method of manufacturing the same are provided.

1 is a cross-sectional view showing a state in which light of a conventional organic light emitting display device is extracted;

2 is a cross-sectional view of an AM organic light emitting display device having a conventional diffraction grating;

3 is a cross-sectional view of an organic light emitting display device according to an exemplary embodiment of the present invention;

4 to 8 are schematic views illustrating steps of manufacturing a light loss prevention layer of the organic light emitting display device illustrated in FIG. 3;

<Description of the symbols for the main parts of the drawings>

100: substrate 110: pixel region

112: first electrode layer 114: organic layer

116: second electrode layer 117: electrode hole

120: driving region 121: buffer layer

122: semiconductor layer 123: gate insulating layer

124: gate electrode 125: internal insulating layer

126: drain electrode 127: source electrode

128: capacitor 129: planarization film

121a: first opening 125a: second opening

129a: third opening 130: light loss prevention layer

In order to achieve the above object, the present invention is a transparent substrate, a first electrode layer formed in a predetermined pattern on the substrate, the top surface is formed on the substrate, the portion of the first electrode layer is exposed A second opening corresponding to the first opening so as to expose a portion of the first electrode layer exposed through the first opening and including a buffer layer having a first opening, and a thin film transistor formed on the buffer layer. Insulating flattening having a driving part forming layer having a third portion and a third opening corresponding to the first opening and the second opening so that a portion of the first electrode layer exposed through the first opening is exposed. An organic layer formed on a film layer, an upper surface of the first electrode layer exposed through the first to third openings, and an upper surface of the organic layer and the planarization film A light loss prevention layer provided between a second electrode layer formed in a predetermined pattern and the substrate and the first electrode layer to prevent the loss of light emitted from the organic layer and having a diffraction grating having a bend on the upper surface of the substrate. It provides an organic light emitting display device comprising a.

According to another feature of the present invention, the thickness of the light loss prevention layer may be 0.01 to 50㎛.

In order to achieve the above object, the present invention also provides a process for forming a light loss prevention layer on a predetermined portion of the upper surface of the transparent substrate, forming a first electrode layer on the upper surface of the light loss prevention layer, and the upper surface of the first electrode layer. Planarizing, patterning the first electrode layer in a predetermined pattern, forming a buffer layer having a first opening to expose a portion of the first electrode layer on an upper surface of the substrate, and forming a buffer layer on the buffer layer And forming a driver forming layer including a thin film transistor electrically connected to the first electrode layer through an electrode hole passing through the buffer layer, and a portion of the first electrode layer exposed through the first opening in the driver forming layer. Forming a second opening corresponding to the first opening so as to be exposed; and insulating the buried driving element formation layer Forming a planarization film layer, forming a third opening corresponding to the first opening and the second opening so that a portion of the first electrode layer exposed through the first opening is exposed to the insulating planarization film layer; Forming an organic layer on an upper surface of the first electrode layer exposed through the first to third openings, and forming a second electrode layer formed in a predetermined pattern on the upper surface of the organic layer and the planarization layer. A method of manufacturing an organic light emitting display device is provided.

In the present invention, the first opening, the electrode hole, and the second opening may be formed in a single process, or the first opening, the second opening, and the third opening may be formed in a single process. can do.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 3 is a cross-sectional view illustrating the structure of an active matrix organic light emitting display (AMOLED) of an AM driving method as an organic electroluminescent display according to an exemplary embodiment of the present invention.

Referring to FIG. 3, a pixel region 110 having a pixel and a transparent electrode for forming the pixel is formed on the transparent substrate 100, and a driving region for driving the electrodes of the pixel region by a thin film transistor TFT and a capacitor. Roughly 120.

The driving region 120 includes a buffer layer 121 formed on the substrate 100, a driver forming layer including a thin film transistor (TFT), a capacitor, and the like formed on the upper surface of the buffer layer 121, and the driver forming layer. The insulating planarization film layer 129 is provided.

The driver forming layer includes a p-type or n-type semiconductor layer 122 arranged in a predetermined pattern on an upper surface of the buffer layer 121, a gate insulating layer 123 filling the semiconductor layer 122, and the gate insulating layer. A gate electrode layer 124 disposed on an upper surface of the gate 123 to correspond to the semiconductor layer 122, an inner insulation layer 125 filling the gap, and a contact formed in the inner insulation layer 125 and the gate insulation layer 123. A thin film transistor comprising a drain electrode 126 and a source electrode 127 connected to both sides of the semiconductor layer 122 through holes 126a and 127a and formed on the inner insulating layer 125, and A first auxiliary electrode 128b connected to the source electrode 127 and formed on an upper surface of the inner insulating layer 125, opposing the first auxiliary electrode 128b and buried in the inner insulating layer 125. And a capacitor 128 consisting of two auxiliary electrodes 128a.

The pixel region 110 is formed adjacent to the driving region 120. The pixel region 110 includes a first electrode layer 112 formed on an upper surface of the substrate 100 and an upper portion of the first electrode layer 112. An organic layer 114 deposited on the second electrode layer 116 formed on the organic layer 114 and the planarization layer 129 of the driving region 120. Unit pixels are formed at portions where the electrode layers 116 intersect.

In this case, the first electrode layer 112 is electrically connected to the drain electrode 126 of the driving region 120 through the electrode hole 117 formed in the buffer layer 121 and the driver forming layer. In other words, an electrode hole 117 penetrating through the buffer layer 121, the gate insulating layer 123, and the internal insulating layer 125 of the driver forming layer is formed in the driving region 120, and thus the first electrode layer 112 is formed therethrough. And the drain electrode 126 are electrically connected.

In addition, a predetermined opening is provided in the driving region 120 to expose the unit pixels of the pixel region 110 through the opening, and the buffer layer 121 corresponds to the first electrode layer 112 corresponding to the unit pixels. A first opening 121a exposing a portion of the first opening 121a, and a portion of the first electrode layer 112 exposed through the first opening 121a is exposed in the driving unit forming layer. The second opening 125a is provided, and the planarization layer 129 has a portion of the first electrode layer 112 exposed through the first opening 121a and the second opening 125a. A third opening 129a corresponding to the opening 121a and the second opening 125a is provided. The second opening 125a is an opening formed in the gate insulating layer 123 and the internal insulating layer 125.

As described above, in the present invention, the pixel region and the driving region are separated from each other without forming the pixel region over the insulating layers of the driving region, and light emitted from the organic layer of the pixel region passes only through the electrode layer and the substrate. Since luminous efficiency is further improved. In addition, the above structure has the advantage that the formation of the light loss prevention layer described later is further facilitated.

As described above, in the organic light emitting display device according to the exemplary embodiment of the present invention as shown in FIG. 3, the first electrode layer 112 is made of ITO, which is a transparent conductive material, and the substrate 100. ) Is provided with a transparent glass can be operated in the bottom emission type. When the organic light emitting display device emits back light, a light loss prevention layer 130 may be provided between the first electrode layer 112 and the transparent substrate 100 to prevent light loss at an interface thereof. The light loss prevention layer 130 is formed between the layers constituting the pixel region 110 of the organic light emitting display, that is, between the layers having a large difference in refractive index among the substrate, the first electrode layer, the organic layer, and the second electrode layer, and the upper surface of the second electrode layer. It is provided on at least one of the side, in the following embodiment is provided between the substrate 100 having a large light loss and the first electrode layer 112 made of ITO.

As shown in FIG. 3, the light loss prevention layer 130 installed in the organic light emitting display device according to the exemplary embodiment of the present invention may be provided with a diffraction grating. The diffraction grating may be formed such that the upper surface of the transparent substrate 100 has a bend provided with a plurality of protrusions 132, and the arrangement of the protrusions 132 may be a dot shape, a stripe shape, and a concentric circle shape. And the like. As described above, the light loss prevention layer 130 provided with the diffraction grating may improve light extraction efficiency by scattering efficiency at the interface between the transparent substrate 100 and the first electrode layer 112. That is, by reflecting the light irradiated to the interface between the transparent substrate 100 and the first electrode layer 112 from the organic layer 114 or more above the critical angle to change within the critical angle it is possible to significantly reduce the reflectance of the light at the interface. Therefore, the light extraction efficiency in which light generated from the organic layer 114 is extracted through the substrate can be increased.

The thickness t1 of the light loss prevention layer 130 is preferably set to 0.03 to 50 μm. In this case, the distance d between the protrusions 132 of the diffraction grating has 50 to 3,000 nm in consideration of reflectance of light. In this case, the distance d may be adjusted according to the wavelength of the light emitted from the organic layer 114. The light loss prevention layer 130 is preferably such that the light transmittance is 80% or more so as to reduce the loss of light generated from the organic layer 114.

In addition, when the optical loss preventing layer 130 is provided with a diffraction grating, the upper surface of the first electrode layer 112 formed thereon is kept flat so that the bending of the diffraction grating is made through the first electrode layer 112. It is not reflected in the organic layer 114. This prevents short circuit between the first electrode layer and the second electrode layer across the organic layer in spite of the curved diffraction grating. In addition, in the organic light emitting display according to the present invention, it is easier to keep the top surface of the first electrode layer 112 flat. This is because the planarization process is performed before the drive region is formed, as will be described later.

As described above, the organic light emitting display device is sealed to the upper portion of the second electrode layer to be blocked from the outside.

Next, a method of manufacturing the organic light emitting display device according to the present invention configured as described above will be described.

In order to manufacture an organic light emitting display device having an optical loss preventing layer 130 provided with a diffraction grating as shown in FIG. 3, first, the first electrode layer 112 may be formed on the substrate 100. As described above, the light loss prevention layer 130 is formed by forming a bent formed with the plurality of protrusions 132 on the upper surface of the substrate 100 where the first electrode layer 112 is to be formed. This bend can be formed in a variety of ways, such as sand blast, laser hologram, half tone, or the like.

Next, as shown in FIG. 5, the first electrode layer 112 is formed on the bent transparent substrate 100. At this time, the shape of the protrusion 132 of the light loss prevention layer 130 is reflected on the first electrode layer 112 as it is, bending 112a appears on the surface.

Accordingly, the surface curvature 112a of the first electrode layer 112 must be removed through a planarization process, as shown in FIG. 6. The planarization of the upper surface of the first electrode layer 112 may be performed relatively easily by using micro-polishing or chemical mechanical polishing (CMP).

In addition, the first electrode layer 112 may be planarized by the following method. First, the slurry for removing an oxide film formed of a mixed solution of SiO 2 and NH 4 OH in a state in which the substrate 100 is rotated at a constant speed is applied to the substrate ( Spraying on the upper surface of the first electrode layer 112 of the 100 and at the same time pressing while pressing at a constant pressure may be used.

After the planarization is completed, the first electrode layer 112 is patterned as shown in FIG. 7, and as shown in FIG. 8, the buffer layer 121 is formed on the upper surface thereof, and then the organic light emitting display device is manufactured as described below. do.

After the light loss prevention layer 130 and the first electrode layer 112 are formed as described above, as shown in FIG. 3, a portion of the first electrode layer 112 formed on the upper surface of the substrate 100 is exposed. 1 The buffer layer 121 having the opening 121a is formed. The first opening 121a may be formed when the opening of the subsequent process is formed. Next, a-Si is deposited on the buffer layer 121, and then crystallized and patterned into poly-Si to form a semiconductor layer 122. The semiconductor layer 122 can be formed in various ways.

After the semiconductor layer 122 is formed, the gate insulating layer 123 is deposited to bury the semiconductor layer 122, the gate metal is deposited on the upper surface thereof, and patterned to correspond to the semiconductor layer 122. The gate electrode layer 124 and the second auxiliary electrode layer 128a are formed. Thereafter, after ion-doped the region where the drain electrode and the source electrode are to be connected to the gate insulating layer 123, an internal insulating layer 125 filling the gate electrode layer 124 is formed, and activation is performed. . After the contact holes 126a and 127a are formed in the internal insulating layer 125 and the gate insulating layer 123 by patterning, the drain electrode 126 and the source electrode 127 are formed and patterned. A first auxiliary electrode 128b connected to the source electrode 127 is formed. When forming the contact holes 126a and 127a, the electrode hole 117 is formed on the upper edge of the first electrode layer 112, and the drain electrode 126 is formed when the drain electrode 126 is formed. 126 and the first electrode layer 112 to be connected. Then, an insulating planarization film 129 is formed on top.

After the driving region 120 is formed, an opening is formed in a portion corresponding to the pixel region 110, and a unit pixel of the pixel region 110 is formed through the opening.

The opening includes a first opening 121a formed in the buffer layer 121, a second opening 125a formed in the driver forming layer, and a third opening 129a formed in the planarization layer 129. That is, an opening may be formed by patterning immediately after the buffer layer 121, the gate insulating layer 123, the internal insulating layer 125, and the planarization layer 129 are formed, and the planarization layer 129 may be formed. After forming all, a single process may form an opening. In addition, except for the third opening 129a of the relatively thick planarization layer 129, the first opening 121a and the second opening 125a may be disposed in the contact holes 126a, 127a and the electrode hole 117. When forming, it forms similarly and the 3rd opening part 129a can be formed separately.

After the openings are formed, the organic layer 114 is deposited on the upper surface of the first electrode layer 112 exposed through the first opening 121a to the third opening 129a, and the organic layer 114 and the planarization layer are formed. The second electrode layer 116 formed in a predetermined pattern on the upper surface of the 129 is formed by a deposition method or the like.

According to the organic light emitting display device and the manufacturing method thereof of the present invention made as described above, the following effects can be obtained.

First, by separating the pixel region from the driving region without forming the pixel region as an upper layer of the insulating layer of the driving region, the number of layers through which light emitted from the organic layer of the pixel region passes through is significantly reduced. It is possible to reduce the number of times passing through the interface, thereby increasing the luminous efficiency.

Second, by forming a light loss prevention layer in a layer having a large refractive index difference, it is possible to reduce the internal loss of light and further increase the light extraction efficiency.

Third, when the optical loss preventing layer of the diffraction grating is formed between the substrate and the first electrode layer, the first electrode layer is formed as the lowermost layer before other layers are formed, so that the top surface of the first electrode layer can be more easily planarized. Therefore, the short circuit between the first electrode layer and the second electrode layer can be prevented.

Although the present invention has been described with reference to one embodiment shown in the drawings, this is merely exemplary and one of ordinary skill in the art will understand that various modifications and variations are possible. Therefore, the present invention will be defined by the technical spirit of the appended claims the true technical protection scope of the present invention.

Claims (5)

Transparent substrates; A first electrode layer formed in a predetermined pattern on the substrate and having a flat top surface; A buffer layer formed on the substrate, the buffer layer having a first opening to expose a portion of the first electrode layer; A driver forming layer formed on the buffer layer and including a thin film transistor and having a second opening corresponding to the first opening so that a portion of the first electrode layer exposed through the first opening is exposed; An insulating planarization film layer having a third opening corresponding to the first opening and the second opening such that a portion of the first electrode layer exposed through the first opening is exposed by filling the driving part forming layer; An organic layer formed on an upper surface of the first electrode layer exposed through the first to third openings; A second electrode layer formed in a predetermined pattern on upper surfaces of the organic layer and the planarization film; And Organic light loss prevention layer positioned between the substrate and the first electrode layer to prevent the loss of light emitted from the organic layer, provided with a diffraction grating having a bend on the upper surface of the substrate; EL display device. The method of claim 1, The thickness of the light loss prevention layer is an organic electroluminescent display device, characterized in that 0.01 to 50㎛. Forming a light loss preventing layer on a predetermined portion of the upper surface of the transparent substrate; Forming a first electrode layer on an upper surface of the light loss prevention layer, and planarizing an upper surface of the first electrode layer; Patterning the first electrode layer in a predetermined pattern; Forming a buffer layer having a first opening to expose a portion of the first electrode layer to an upper surface of the substrate; Forming a driver forming layer on the buffer layer, the driver forming layer including a thin film transistor electrically connected to the first electrode layer through an electrode hole passing through the buffer layer; Forming a second opening portion corresponding to the first opening portion to expose the portion of the first electrode layer exposed through the first opening portion in the driving portion forming layer; Forming an insulating planarization film layer filling the drive element formation layer; Forming a third opening corresponding to the first opening and the second opening so that a portion of the first electrode layer exposed through the first opening is exposed in the insulating planarization film layer; Forming an organic layer on an upper surface of the first electrode layer exposed through the first to third openings; And And forming a second electrode layer formed in a predetermined pattern on the upper surface of the organic layer and the planarization layer. The method of claim 3, The first opening, the electrode hole, and the second opening are formed in a single process. The method of claim 3, And the first opening, the second opening, and the third opening are formed in a single process.