KR20190071295A - Organic light emitting display device - Google Patents

Abstract

The present invention is to provide an organic light emitting display device capable of preventing the light efficiency from being lowered. According to the present invention, the organic light emitting display device comprises: a thin film transistor disposed on a first substrate; an organic light emitting element disposed on the thin film transistor; and an encapsulation film covering the organic light emitting element. The encapsulation film includes a lower inorganic film in contact with the organic light emitting element, an organic film disposed on the lower inorganic film, and an upper inorganic film covering the organic film. Each of the lower inorganic film and the upper inorganic film has different refractive indices on one surface in contact with the organic film and the other surface not in contact with the organic film.

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to an organic light-

The present invention relates to an organic light emitting display.

As the information society develops, there is a growing demand for display devices for displaying images. In recent years, various display devices such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting display (OLED) have been used.

Of the display devices, the organic light emitting display device is a self-emitting type, and has a better viewing angle and contrast ratio than a liquid crystal display device (LCD), does not require a separate backlight and is lightweight and thin, . In addition, the organic light emitting display device is capable of being driven by a DC low voltage, has a high response speed, and is particularly advantageous in manufacturing cost.

The organic light emitting display has a structure in which an organic light emitting device including a light emitting layer is provided between a cathode for injecting electrons and an anode for injecting holes. When the electrons generated in the cathode and the holes generated in the anode are injected into the light emitting layer, the injected electrons and holes are combined with each other to generate an exciton, and the generated excitons are excited. To a ground state, and emits light.

However, the organic light emitting display device includes an organic light emitting element in each pixel, and the organic light emitting element is easily deteriorated by external factors such as moisture and oxygen. In order to prevent this, the organic light emitting display device forms a sealing film covering the organic light emitting device so that external moisture and oxygen do not penetrate the organic light emitting device.

The sealing film sequentially stacks the at least one inorganic film and the at least one organic film to prevent oxygen or moisture from permeating into the display region where the organic light emitting layer and the electrode are provided.

At this time, the inorganic film and the organic film have different refractive indexes. Therefore, when the light generated in the organic light emitting device is incident on the sealing film, total internal reflection occurs while passing through the inorganic film and the organic film having different refractive indices in order. Accordingly, the conventional organic light emitting display device has a problem that the light efficiency is degraded because light is lost by the sealing film in which the inorganic film and the organic film having different refractive indexes are stacked and is not emitted to the outside.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and it is an object of the present invention to provide an organic light emitting display device capable of preventing light efficiency from being lowered.

According to another aspect of the present invention, there is provided an organic light emitting display including a thin film transistor disposed on a first substrate, an organic light emitting element disposed on the thin film transistor, and a sealing film covering the organic light emitting element, Wherein the lower inorganic film and the upper inorganic film each have a refractive index different from that of the one surface contacting the organic film and the other surface not contacting the organic film, And an organic light emitting display device.

Since the difference in refractive index between the lower inorganic film and the organic film is small and the refractive index difference at the interface between the upper inorganic film and the organic film is small, the light generated in the organic light- Penetrates into the organic film, passes through the organic film and is incident on the upper inorganic film, the total internal reflection hardly occurs, thereby preventing the light efficiency from being lowered.

The effects obtained in the present invention are not limited to the effects mentioned above, and other effects not mentioned can be clearly understood by those skilled in the art from the following description .

1 is a perspective view illustrating an OLED display according to an embodiment of the present invention.
2 is a plan view showing the first substrate, the gate driver, the source drive IC, the flexible film, the circuit board, and the timing controller of FIG.
FIG. 3 is a cross-sectional view schematically showing one side of an organic light emitting diode display according to an exemplary embodiment, taken along line I-I 'of FIG.
4 is a plan view schematically illustrating a first substrate according to an example.
FIG. 5 is a cross-sectional view of the organic light emitting diode display according to one embodiment of the present invention, taken along line II-II 'of FIG.
6 is a cross-sectional view of the sealing film according to the first embodiment of the present invention, and is an enlarged view of a portion A in Fig.
7 is a cross-sectional view of a sealing film according to a second embodiment of the present invention, and is an enlarged view of a portion A in Fig.
8A and 8B are graphs of light transmittance of an OLED display according to a second embodiment of the present invention.

The meaning of the terms described herein should be understood as follows.

The word " first, "" second," and the like, used to distinguish one element from another, are to be understood to include plural representations unless the context clearly dictates otherwise. The scope of the right should not be limited by these terms. It should be understood that the terms "comprises" or "having" does not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof. It should be understood that the term "at least one" includes all possible combinations from one or more related items. For example, the meaning of "at least one of the first item, the second item and the third item" means not only the first item, the second item or the third item, but also the second item and the second item among the first item, Means any combination of items that can be presented from more than one. The term "on" means not only when a configuration is formed directly on top of another configuration, but also when a third configuration is interposed between these configurations.

Hereinafter, preferred embodiments of the organic light emitting display according to the present invention will be described in detail with reference to the accompanying drawings. In the drawings, like reference numerals are used to denote like elements throughout the drawings, even if they are shown on different drawings. In the following description of the present invention, a detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear.

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

FIG. 1 is a perspective view showing an organic light emitting diode display according to an embodiment of the present invention, FIG. 2 is a plan view showing a first substrate, a gate driver, a source drive IC, a flexible film, a circuit board, and a timing controller of FIG. 1 .

1 and 2, an organic light emitting diode display 10 according to an exemplary embodiment of the present invention includes a display panel 11, a gate driver 12, an integrated circuit (IC) 13, a flexible film 14, a circuit board 15,

The display panel 11 includes a first substrate S1 and a second substrate S2. The second substrate S2 may be an encapsulating substrate. The first substrate S1 and the second substrate S2 may be plastic or glass.

remind Gate lines, data lines, and pixels are formed on one surface of the first substrate S1 facing the second substrate S2. The pixels are provided in an area defined by the intersection structure of the gate lines and the data lines.

Each of the pixels may include a thin film transistor and an organic light emitting element having a first electrode, an organic light emitting layer, and a second electrode. Each of the pixels supplies a predetermined current to the organic light emitting element in accordance with the data voltage of the data line when the gate signal is inputted from the gate line by using the thin film transistor. Thus, the organic light emitting element of each of the pixels can emit light with a predetermined brightness according to a predetermined current. A detailed description of the structure of each of the pixels will be described later with reference to FIG.

The display panel 11 may be divided into a display area DA in which pixels are formed and an image is displayed and a non-display area NDA in which no image is displayed, as shown in FIG. Gate lines, data lines, and pixels may be formed in the display area DA. A gate driver 12 and pads may be formed in the non-display area NDA.

remind The gate driver 12 supplies gate signals to the gate lines according to a gate control signal input from the timing controller 16. [ The gate driver 12 may be formed in a non-display area NDA on one side or both sides of the display area DA of the display panel 11 in a gate driver in panel (GIP) manner. Alternatively, the gate driver 12 may be formed of a driving chip, mounted on a flexible film, and mounted on a non-display area NDA on one side or both sides of the display area DA of the display panel 11 by TAB (tape automated bonding) As shown in FIG.

remind The source drive IC 13 receives the digital video data and the source control signal from the timing control unit 16. [ The source driver IC 13 converts the digital video data into analog data voltages according to the source control signal and supplies them to the data lines. When the source drive IC 13 is fabricated from a drive chip, it can be mounted on the flexible film 14 by a COF (chip on film) or a COP (chip on plastic) method.

Pads such as data pads may be formed in the non-display area NDA of the display panel 11. [ Wires connecting the pads and the source drive IC 13 and wirings connecting the pads and the wirings of the circuit board 15 may be formed in the flexible film 14. [ The flexible film 14 is attached on the pads using an anisotropic conducting film, whereby the pads and the wirings of the flexible film 14 can be connected.

remind The circuit board 15 may be attached to the flexible films 14. [ The circuit board 15 may be mounted with a plurality of circuits implemented with driving chips. For example, the timing control section 16 may be mounted on the circuit board 15. [ The circuit board 15 may be a printed circuit board or a flexible printed circuit board.

remind The timing control unit 16 receives digital video data and a timing signal from an external system board through a cable of the circuit board 15. The timing control section 16 generates a gate control signal for controlling the operation timing of the gate driving section 12 and a source control signal for controlling the source drive ICs 13 based on the timing signal. The timing control section 16 supplies a gate control signal to the gate driving section 12 and supplies a source control signal to the source drive ICs 13. [

FIG. 3 is a cross-sectional view schematically showing one side of an organic light emitting diode display according to an exemplary embodiment, taken along line I-I 'of FIG.

3, the display panel 11 includes a first substrate S1, a second substrate S2, a thin film transistor layer 100 disposed between the first and second substrates S1 and S2, A light emitting device layer 200, and an encapsulation layer 300.

The first substrate S1 may be a plastic film or a glass substrate.

The thin film transistor layer 100 is disposed on the first substrate S1. The thin film transistor layer 100 may include gate lines, data lines, and thin film transistors. Each of the thin film transistors includes a gate electrode, a semiconductor layer, and source and drain electrodes. When the gate driver is formed by a gate driver in panel (GIP) scheme, the gate driver may be formed together with the thin film transistor layer 100.

The organic light emitting device layer 200 is disposed on the thin film transistor layer 100. The organic light emitting device layer 200 includes a first electrode, an organic light emitting layer, a second electrode, and a bank. Each of the organic light emitting layers may include a hole transporting layer, an organic light emitting layer, and an electron transporting layer. In this case, when a voltage is applied to the first electrode and the second electrode, holes and electrons move to the light emitting layer through the hole transporting layer and the electron transporting layer, respectively, and light is emitted from the light emitting layer. Since the pixels are disposed in the region where the organic light emitting device layer 200 is disposed, the region where the organic light emitting device layer 200 is disposed may be defined as a display region. The peripheral area of the display area can be defined as a non-display area.

The sealing layer 300 is disposed on the organic light emitting device layer 200. The sealing layer 300 prevents oxygen or moisture from penetrating into the organic light emitting device layer 200. The sealing layer 300 may include at least one organic film and an inorganic film.

Hereinafter, an organic light emitting display according to an embodiment of the present invention will be described in more detail with reference to FIGS. 4 and 5. FIG.

FIG. 4 is a plan view schematically showing a first substrate according to one example, and FIG. 5 is a cross-sectional view of the organic light emitting diode display according to an embodiment of the present invention, taken along line II-II 'of FIG.

4 and 5, the first substrate S1 is divided into a display area DA and a non-display area NDA, and a dam (DAM) may be formed in the non-display area NDA.

A thin film transistor layer 100, an organic light emitting device layer 200, and an encapsulating layer 300 are formed on a display region DA of the first substrate S1.

The thin film transistor layer 100 includes thin film transistors 120, a gate insulating layer 130, an interlayer insulating layer 140, and a planarization layer 150.

A buffer film 110 may be disposed on one surface of the first substrate S1. The buffer layer 110 is disposed on one surface of the first substrate S1 to protect the thin film transistors 120 and the organic light emitting devices 210 from moisture penetrating through the first substrate S1 susceptible to moisture permeation do. One surface of the first substrate S1 may be a surface facing the second substrate S2. The buffer film 110 may be formed of a plurality of alternately stacked inorganic films. For example, the buffer film 110 may be formed of multiple films in which one or more inorganic films of a silicon oxide film (SiOx), a silicon nitride film (SiNx), and SiON are alternately stacked. The buffer film 110 may be omitted.

The thin film transistor 120 is disposed on the buffer film 110. The thin film transistor 120 includes an active layer 121, a gate electrode 122, a source electrode 123, and a drain electrode 124. [ 5, the thin film transistor 120 is formed by a top gate method in which the gate electrode 122 is located on the top of the active layer 121. However, the present invention is not limited thereto. That is, the thin film transistors 120 may be formed by a bottom gate method in which the gate electrode 122 is located under the active layer 121 or a bottom gate method in which the gate electrode 122 is formed on the upper and lower portions of the active layer 121 And may be formed in a double gate manner.

The active layer 121 is disposed on the buffer layer 110. The active layer 121 may be formed of a silicon-based semiconductor material or an oxide-based semiconductor material. A light shielding layer for shielding external light incident on the active layer 121 may be disposed between the buffer layer 110 and the active layer 121. [

The gate insulating layer 130 may be disposed on the active layer 121. The gate insulating film 130 may be formed of an inorganic film, for example, a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer film thereof.

The gate electrode 122 and the gate line may be disposed on the gate insulating layer 130. The gate electrode 122 and the gate line may be formed of any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd) Or a single layer or multiple layers of one or more of these alloys.

The interlayer insulating layer 140 may be disposed on the gate electrode 122 and the gate line. The interlayer insulating film 140 may be formed of an inorganic film, for example, a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer film thereof.

The source electrode 123, the drain electrode 124, and the data line 125 may be disposed on the interlayer insulating layer 140. Each of the source electrode 123 and the drain electrode 124 may be connected to the active layer 121 through a contact hole passing through the gate insulating film 130 and the interlayer insulating film 140. The source electrode 123, the drain electrode 124 and the data line 125 are formed of a metal such as Mo, Al, Cr, Au, Ti, Ni, (Nd), and copper (Cu), or an alloy thereof.

A protective film (not shown) for insulating the TFT 120 may be disposed on the source electrode 123, the drain electrode 124, and the data line 125. The protective film may be formed of an inorganic film, for example, a silicon oxide film (SiOx), a silicon nitride film (SiNx), or a multilayer thereof. The protective film may be omitted.

The planarization layer 150 may be disposed on the interlayer insulating layer 140 to flatten a step due to the thin film transistor 120. The planarization layer 150 may be formed of an organic layer such as an acryl resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin. have.

The organic light emitting device layer 200 is disposed on the thin film transistor layer 100. The organic light emitting device layer 200 includes an organic light emitting device 210 and a bank 220.

The organic light emitting diode 210 and the bank 220 are disposed on the thin film transistor 120 and the planarization layer 150. The organic light emitting device 210 includes a first electrode 211, an organic light emitting layer 212, and a second electrode 213.

remind The first electrode 211 may be disposed on the planarization layer 150. The first electrode 211 is connected to the source electrode 123 of the thin film transistor 120 through the contact hole passing through the planarization film 150. The first electrode 211 is formed of a laminated structure of aluminum and titanium (Ti / Al / Ti), a laminated structure of aluminum and ITO (ITO / Al / ITO), an APC alloy, / ITO). ≪ / RTI > The APC alloy is an alloy of silver (Ag), palladium (Pd), and copper (Cu).

The bank 220 may be disposed on the planarization layer 150 and the first electrode 211. The bank 220 may be arranged to cover the edge of the first electrode 211 on the planarization film 150 to partition the pixels. That is, the bank 220 serves as a pixel defining layer for defining pixels. The bank 220 may be formed of an organic film such as an acryl resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin .

The organic light emitting layer 212 is disposed on the first electrode 211 and the bank 220. The organic light emitting layer 212 may include a hole transporting layer, at least one light emitting layer, and an electron transporting layer. In this case, when a voltage is applied to the first electrode 211 and the second electrode 213, holes and electrons move to the light emitting layer through the hole transporting layer and the electron transporting layer, respectively.

The organic light emitting layer 212 may be a white light emitting layer that emits white light. In this case, the organic light emitting layer 212 may be disposed to cover the first electrode 211 and the bank 220. A color filter (not shown) may be disposed on the second substrate S2.

Alternatively, the organic light emitting layer 212 may include a red light emitting layer for emitting red light, a green light emitting layer for emitting green light, or a blue light emitting layer for emitting blue light. In this case, the organic light emitting layer 212 may be disposed in a region corresponding to the first electrode 211, and the color filter may not be disposed on the second substrate S2.

The second electrode 213 is disposed on the organic light emitting layer 212. The second electrode 213 may be formed of a transparent conductive material such as ITO or IZO or a transparent conductive material such as magnesium Mg ), Silver (Ag), or a semi-transmissive metal material such as an alloy of magnesium (Mg) and silver (Ag). A capping layer may be disposed on the second electrode 213.

The sealing layer 300 may be extended to the display area DA of the first substrate S1 as well as to the non-display area NDA on the organic light emitting device layer 200. [ The sealing layer 300 according to an exemplary embodiment of the present invention includes a sealing film 310 and a dam (DAM).

The sealing film 310 is disposed on the bank 220 and is disposed to cover the display area DA so as to prevent oxygen or moisture from penetrating the organic light emitting layer 212 and the second electrode 213 do. For this purpose, the sealing film 310 may comprise at least one inorganic film and at least one organic film.

The sealing film 310 according to an embodiment of the present invention may include a lower inorganic film 311, an organic film 312, and an upper inorganic film 313.

The lower inorganic film 311 may be disposed on the second electrode 213. The lower inorganic film 311 may be disposed to cover the second electrode 213. Specifically, the lower inorganic film 311 may be arranged to cover the second electrode 262 and the bank 220 in the display area DA, extend to the non-display area NDA, and cover the dam DAM have.

The organic film 312 is disposed on the lower inorganic film 311 to compensate for defects and steps that may occur in the lower inorganic film 311. The organic layer 312 prevents the particles from penetrating the organic light emitting layer 212 and the second electrode 213 through the lower inorganic layer 311 and may be formed to have a sufficient thickness have. The organic film 312 may be formed on a substrate in a liquid form through an inkjet process, and then may be formed through a curing process.

The upper inorganic film 313 may be disposed on the organic film 312. The upper inorganic film 313 may be disposed so as to cover the organic film 312. The upper inorganic film 313 covers the organic film 312 in the display area DA and extends to the non-display area NDA to cover the dam DAM and the lower inorganic film 311 . The upper inorganic film 313 is free from defects or step differences due to the organic film 312 disposed at the lower portion thereof and therefore no path is formed through which moisture is blown into the inside of the device, Can be prevented from being degraded in reliability and quality.

Each of the lower and upper inorganic films 311 and 313 may be formed of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, or titanium oxide. The organic layer 312 may be formed of an acryl resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

On the other hand, the lower and upper inorganic films 311 and 313 and the organic film 312 have different refractive indices. The lower and upper inorganic films 311 and 313 according to an example have a refractive index higher than that of the organic film 312. Therefore, when the light generated in the organic light emitting device 210 is incident on the sealing film 310, the total internal reflection passes through the lower and upper inorganic films 311 and 313 and the organic film 312, Occurs. Accordingly, the conventional organic light emitting display device has a problem in that light efficiency is lowered because light is lost by the sealing film 310 in which inorganic and organic layers having different refractive indexes are stacked and is not emitted to the outside.

In order to solve such a problem, the organic light emitting diode display according to an embodiment of the present invention includes a sealing film 310, a lower refractive index difference at the interface between the upper and lower inorganic films 311 and 313 and the organic film 312, .

More specifically, the lower inorganic film 311 of the sealing film 310 according to an embodiment of the present invention gradually decreases in refractive index from one surface contacting the second electrode 213 to the other surface contacting the organic film 312 . Therefore, since the refractive index difference at the interface between the lower inorganic film 311 and the organic film 312 is small, the light generated in the organic light emitting device 210 is emitted to the lower side Even if the light passes through the inorganic film 311 and enters the organic film 312, total internal total reflection does not occur.

The refractive index of the upper inorganic film 313 of the sealing film 310 gradually increases from one surface contacting the organic film 312 to the other surface not contacting the organic film 312 according to an embodiment of the present invention. Therefore, since the refractive index difference at the interface between the upper inorganic film 313 and the organic film 312 is small, the organic light emitting display according to the embodiment of the present invention can reduce the light generated from the organic light emitting element 210 to the organic Even though the light is incident on the upper inorganic film 313 through the film 312, total internal total reflection does not occur.

Accordingly, the organic light emitting diode display according to the embodiment of the present invention gradually changes the refractive indexes of the lower and upper inorganic films 311 and 313 so that the light emitted from the organic light emitting device 210 is reflected by the lower and upper inorganic films 311, and 313 and the organic film 312 in this order, the loss due to total internal reflection is reduced, thereby preventing the light efficiency from being lowered.

remind The dam DAM is disposed in the non-display area NDA to block the flow of the organic film 312 constituting the sealing film 310. More specifically, the dam DAM is disposed so as to surround the outside of the display area DA to block the flow of the organic film 312 constituting the sealing film 310. The dam DAM is disposed in the non-display area NDA to cover the organic film 312 so that the organic film 312 constituting the sealing film 310 can not penetrate into the pad (not shown) exposed by the contact hole. Can be blocked. Thus, the dam (DAM) can prevent the organic film 312 from being exposed to the outside of the display device or from penetrating into the pad.

The dam (DAM) according to one embodiment of the present invention includes an inner dam (ID) and an outer dam (OD).

The inner dam ID is disposed adjacent to the display area DA and is disposed so as to surround the outer periphery of the display area DA to primarily block the flow of the organic film 312 constituting the sealing film 310 . The internal dam ID is disposed between the display area DA and the pad area PA to prevent the organic film 312 from being exposed to the exposed pad .

The external dam (OD) is disposed so as to surround the outer perimeter of the inner dam (ID), and is spaced apart from the inner dam (ID) and arranged side by side. At this time, the interval between the external dam (OD) and the internal dam (ID) is about 30 to 40 um, but the present invention is not limited thereto. The external dam (OD) can secondarily block the organic film (312) flowing over to the outside of the internal dam (ID). Also, the height of the outer dam OD may be higher than the height of the inner dam ID. Accordingly, the internal dam (ID) and the external dam (OD) can more effectively block the organic film 312 from being exposed to the outside of the organic light emitting display device 10 or from penetrating the exposed pads.

The inner dam ID according to an example of the present invention includes a first inner dam ID1 disposed on the interlayer insulating film 140 and a second inner dam ID2 disposed on the first inner dam ID1, . ≪ / RTI > The outer dam OD according to an exemplary embodiment of the present invention includes a first outer dam OD1 disposed on the interlayer insulating layer 140, a second outer dam OD2 disposed on the first outer dam OD1, , And a third outer dam (OD3) disposed on the second outer dam (OD2). At this time, the first outer dam OD1 may be formed of the same material as the flattening film 150. [ The first inner dam ID1 and the second outer dam OD2 have the same material and can be formed of the same material as the bank 220. [ The second inner dam ID2 and the third outer dam OD3 have the same material and can be formed of the same material as a spacer (not shown) disposed on the bank 220. [ Accordingly, the dam (DAM) according to an exemplary embodiment of the present invention can be formed at the same time when forming the planarization film 150, the bank 220, and the spacer, and can be formed without any additional process.

The organic light emitting display according to an exemplary embodiment of the present invention gradually changes the refractive index of the sealing film 310 so that the light emitted from the organic light emitting diode 210 is reflected by the lower and upper inorganic films 311 and 313 And the organic film 312 in this order, the loss due to the total internal reflection decreases, thereby preventing the light efficiency from being lowered.

6 is a cross-sectional view of the sealing film according to the first embodiment of the present invention, and is an enlarged view of a portion A in Fig.

Referring to FIG. 6, the sealing film 310 according to the first embodiment of the present invention includes a lower inorganic film 311, an organic film 312, and an upper inorganic film 313.

The lower inorganic film 311 according to the first embodiment of the present invention includes a first lower inorganic film 311a in contact with the organic light emitting element 210 and a second lower inorganic film 311b disposed on the first lower inorganic film 311a. Film 311b.

The first lower inorganic film 311 a is disposed on the second electrode 213. The first lower inorganic film 311a according to the first embodiment of the present invention may contain less amount of nitrous oxide N2O than the second lower inorganic film 311b or may not contain nitrous oxide N2O , Silicon nitride (SiNx). As the amount of nitrous oxide (N2O) contained in the inorganic film increases, the refractive index of the inorganic film decreases. Accordingly, the first lower inorganic film 311a according to the first embodiment of the present invention has a refractive index different from that of the second lower inorganic film 311b disposed on the upper side. The first lower inorganic film 311a according to an example may have a refractive index of about 1.85.

The second lower inorganic film 311b is disposed on the first lower inorganic film 311a. The second lower inorganic film 311b according to the first embodiment of the present invention includes more nitrous oxide (N2O) than the first lower inorganic film 311a and may be formed of silicon oxynitride (SiON). Accordingly, the second lower inorganic film 311b according to the first embodiment of the present invention has a refractive index different from that of the first lower inorganic film 311a disposed below. More specifically, the second lower inorganic film 311b according to the first embodiment of the present invention has a refractive index lower than that of the first lower inorganic film 311a. The second lower inorganic film 311b according to an example may have a refractive index of about 1.6 to 1.84.

The organic layer 312 has a refractive index lower than that of the second lower inorganic layer 311b. The organic film 312 according to one example may have a refractive index of 1.5. The encapsulation film 310 according to the first embodiment of the present invention is formed such that the difference in refractive index between the second lower inorganic film 311b and the organic film 312 is larger than that between the first lower inorganic film 311a and the organic film 312 Refractive index difference.

That is, the refractive index of the lower inorganic film 311 of the sealing film 310 according to the first embodiment of the present invention gradually decreases from one surface contacting the second electrode 213 to the other surface contacting the organic film 312. Therefore, since the difference in refractive index between the lower inorganic film 311 and the organic film 312 is small, the light emitted from the organic light emitting device 210 can be emitted from the organic light emitting display device according to the first embodiment of the present invention. Even though the light passes through the lower inorganic film 311 and enters the organic film 312, total internal total reflection does not occur.

The upper inorganic film 313 according to the first embodiment of the present invention includes a first upper inorganic film 313a in contact with the organic film 312 and a second upper inorganic film 313b disposed on the first upper inorganic film 313a, (313b).

The first upper inorganic film 313 a is disposed on the organic film 312. The first upper inorganic film 313a according to the first embodiment of the present invention includes more nitrous oxide (N2O) than the second upper inorganic film 313b and may be made of silicon oxynitride (SiON). Therefore, the first upper inorganic film 313a according to the first embodiment of the present invention has a refractive index different from that of the second upper inorganic film 313b disposed on the upper side. More specifically, the first upper inorganic film 313a according to the first embodiment of the present invention has a refractive index lower than that of the second upper inorganic film 313b. The first upper inorganic film 313a according to an example may have a refractive index of about 1.6 to 1.84.

The second upper inorganic film 313b is disposed on the first upper inorganic film 313a. The second upper inorganic film 313b according to the first embodiment of the present invention may contain less amount of nitrous oxide N2O than the first upper inorganic film 313a or may not contain nitrous oxide N2O , Silicon nitride (SiNx). As the amount of nitrous oxide (N2O) contained in the inorganic film increases, the refractive index of the inorganic film decreases. Accordingly, the second upper inorganic film 313b according to the first embodiment of the present invention has a refractive index different from that of the first upper inorganic film 313a disposed below. More specifically, the second upper inorganic film 313b according to the first embodiment of the present invention has a refractive index higher than that of the first upper inorganic film 313a. The second upper inorganic film 313b according to an example may have a refractive index of about 1.85.

At this time, the organic film 312 according to the first embodiment of the present invention has a refractive index lower than that of the first upper inorganic film 313a. The refractive index difference between the first upper inorganic film 313a and the organic film 312 is smaller than the refractive index difference between the second upper inorganic film 313b and the organic film 312. That is, the refractive index of the upper inorganic film 313 of the sealing film 310 according to the first embodiment of the present invention gradually increases from one surface contacting the organic film 312 to the other surface not contacting the organic film 312 .

Therefore, since the difference in refractive index between the upper inorganic film 313 and the organic film 312 is small, the light emitted from the organic light emitting device 210 can be emitted Even if the light passes through the organic film 312 and enters the upper inorganic film 313, total internal total reflection does not occur.

In the organic light emitting diode display according to the first embodiment of the present invention, the ratio of nitrous oxide (N2O) to the lower and upper inorganic films 311 and 313 may be gradually changed, or silicon nitride (SiNx) The refractive index of the lower and upper inorganic films 311 and 313 can be gradually changed by multilayer deposition of an inorganic film made of ridon (SiON). Therefore, even if the light emitted from the organic light emitting diode 210 passes through the lower and upper inorganic films 311 and 313 and the organic film 312 in order, Thereby reducing the optical efficiency.

7 is a cross-sectional view of a sealing film according to a second embodiment of the present invention, and is an enlarged view of a portion A in Fig.

The sealing film 310 shown in Fig. 7 is the same as the sealing film 310 described above with reference to Fig. 6 except that a third lower inorganic film 311c and a third upper inorganic film 313c are added. Accordingly, only the third lower inorganic film 311c and the third upper inorganic film 313c will be described in the following description, and a duplicate description of the same constitution will be omitted.

7, the sealing film 310 includes a lower inorganic film 311, an organic film 312, and an upper inorganic film 313 in the second embodiment of the present invention.

The lower inorganic film 311 according to the second embodiment of the present invention includes a first lower inorganic film 311a in contact with the organic light emitting element 210, a second lower inorganic film 311b disposed on the first lower inorganic film 311a, A third lower inorganic film 311b disposed on the second lower inorganic film 311b, and a third lower inorganic film 311c disposed on the second lower inorganic film 311b.

The third lower inorganic film 311c is disposed on the second lower inorganic film 311b. The third lower inorganic film 311c according to the second embodiment of the present invention includes more nitrous oxide (N2O) than the second lower inorganic film 311b and may be formed of silicon oxynitride (SiON). Therefore, the third lower inorganic film 311c according to the second embodiment of the present invention has a refractive index different from that of the second lower inorganic film 311b and the first lower inorganic film 311a disposed below. More specifically, the third lower inorganic film 311c according to the second embodiment of the present invention has a refractive index lower than that of the second lower inorganic film 311b and the first lower inorganic film 311a. The third lower inorganic film 311c according to an example may have a refractive index of about 1.55 to 1.7.

The organic film 312 has a refractive index lower than that of the third lower inorganic film 311c. The organic film 312 according to one example may have a refractive index of 1.5. Therefore, the encapsulation film 310 according to the second embodiment of the present invention is formed such that the difference in refractive index between the third lower inorganic film 311c and the organic film 312 is smaller than the refractive index difference between the first lower inorganic film 311a or the second lower inorganic film 311b and the organic film 312. In this case,

That is, the refractive index of the lower inorganic film 311 of the sealing film 310 according to the second embodiment of the present invention gradually decreases from one surface contacting the second electrode 213 to the other surface contacting the organic film 312. Therefore, since the difference in refractive index between the lower inorganic film 311 and the organic film 312 is small, the light generated from the organic light emitting device 210 can be emitted from the organic light emitting display device according to the second embodiment of the present invention. Even though the light passes through the lower inorganic film 311 and enters the organic film 312, total internal total reflection does not occur.

The upper inorganic film 313 according to the second embodiment of the present invention includes a first upper inorganic film 313a in contact with the organic film 312, a second upper inorganic film 313a disposed on the first upper inorganic film 313a, 313b, and a third upper inorganic film 313c disposed on the second upper inorganic film 313b.

The third upper inorganic film 313c is disposed on the second upper inorganic film 313b. The third upper inorganic film 313c according to the second embodiment of the present invention may contain less amount of nitrous oxide N2O than the second upper inorganic film 313b or may not contain nitrous oxide N2O , Silicon nitride (SiNx). As the amount of nitrous oxide (N2O) contained in the inorganic film increases, the refractive index of the inorganic film decreases. Therefore, the third upper inorganic film 313c according to the second embodiment of the present invention has a refractive index different from that of the second upper inorganic film 313b and the first upper inorganic film 313a disposed below. More specifically, the third upper inorganic film 313c according to the second embodiment of the present invention has a higher refractive index than the second upper inorganic film 313b and the first upper inorganic film 313a. The third upper inorganic film 313c may have a refractive index of about 1.85, and the second upper inorganic film 313b may have a refractive index of about 1.75 to about 1.84.

At this time, the organic film 312 according to the second embodiment of the present invention has a refractive index lower than that of the first upper inorganic film 313a. The refractive index difference between the second upper inorganic film 313b and the organic film 312 is smaller than the refractive index difference between the third upper inorganic film 313c and the organic film 312. That is, the refractive index of the upper inorganic film 313 of the sealing film 310 according to the second embodiment of the present invention gradually increases from one surface contacting the organic film 312 to the other surface not contacting the organic film 312 .

Accordingly, since the difference in refractive index between the upper inorganic film 313 and the organic film 312 is small, the light emitted from the organic light emitting device 210 can be emitted Even if the light passes through the organic film 312 and enters the upper inorganic film 313, total internal total reflection does not occur.

The organic light emitting display according to the second exemplary embodiment of the present invention may be formed by gradually changing the ratio of nitrous oxide N2O to the lower and upper inorganic films 311 and 313 or by depositing silicon nitride (SiNx) The refractive index of the lower and upper inorganic films 311 and 313 can be gradually changed by multi-layer deposition of an inorganic film made of oxynitride (SiON). Therefore, even though the light emitted from the organic light emitting diode 210 passes through the lower and upper inorganic films 311 and 313 and the organic film 312 in order, the organic light emitting display according to the second embodiment of the present invention can reduce Thereby reducing the optical efficiency.

Meanwhile, the organic light emitting diode display according to an exemplary embodiment of the present invention includes a lower inorganic film 311 and an upper inorganic film 313, and the lower the refractive index difference is formed for each interface as the number of layers having different refractive indexes is increased It is possible to reduce the loss due to the total internal reflection considerably, thereby preventing the light efficiency from being lowered.

8A and 8B are graphs of light transmittance of an OLED display according to a second embodiment of the present invention.

FIG. 8A shows light transmittance when a lower inorganic film and an upper inorganic film of a conventional organic light emitting diode display are formed as a single layer, and FIG. 8B shows a light transmittance of the organic light emitting display according to the second embodiment of the present invention .

Referring to FIG. 8A, the conventional organic light emitting display has a light transmittance of about 77.5% to 91.5%, a light transmittance of about 77.5% when the light transmittance is the lowest, and a light transmittance of 91.5% not. Therefore, in the conventional organic light emitting diode display, light is lost by the sealing film formed by stacking the inorganic layers of a single layer, and is not emitted to the outside, so that the light transmittance is lowered and the light efficiency is lowered.

Referring to FIG. 8B, the organic light emitting diode display according to the second embodiment of the present invention has a light transmittance of about 90% to 100%, a light transmittance of about 90% when the light transmittance is the lowest, And when the light transmittance is the highest, it is as high as about 100%. Therefore, in the organic light emitting diode display according to the second embodiment of the present invention, most of the light emitted from the organic light emitting diode 210 is transmitted outside the sealing film 310, so that the light transmittance is high and thus the light efficiency is increased .

Although the embodiments of the present invention have been described in detail with reference to the accompanying drawings, it is to be understood that the present invention is not limited to those embodiments and various changes and modifications may be made without departing from the scope of the present invention. . Therefore, the embodiments disclosed in the present invention are intended to illustrate rather than limit the scope of the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. Therefore, it should be understood that the above-described embodiments are illustrative in all aspects and not restrictive. The scope of protection of the present invention should be construed according to the claims, and all technical ideas within the scope of equivalents should be interpreted as being included in the scope of the present invention.

10: organic light emitting display device 11: display panel
S1: first substrate S2: second substrate
12: Gate driver 13: Source drive IC
14: flexible film 15: circuit board
16: timing control section 100: thin film transistor layer
110: buffer film 120: thin film transistor
121: active layer 122: gate electrode
123: source electrode 124: drain electrode
130: gate insulating film 140: interlayer insulating film
150: planarization film 200: organic light emitting element layer
210: organic light emitting device 211: first electrode
212: organic light emitting layer 213: second electrode
220: bank 300: sealing layer
310: sealing film 311: lower inorganic film
312: organic film 313: upper inorganic film
DAM: Dam ID: Internal dam
OD: External dam

Claims (13)

A thin film transistor disposed on the first substrate;
An organic light emitting element disposed on the thin film transistor; And
And a sealing film covering the organic light emitting element,
The sealing film may be formed,
A lower inorganic film in contact with the organic light emitting element;
An organic film disposed on the lower inorganic film; And
And an upper inorganic film covering the organic film,
Wherein each of the lower inorganic film and the upper inorganic film has a refractive index different from that of one side contacting the organic film and the other side not contacting the organic film. The method according to claim 1,
Wherein each of the lower inorganic film and the upper inorganic film has a refractive index of one side in contact with the organic film, which is lower than a refractive index of the other side not in contact with the organic film. The method according to claim 1,
Wherein the lower inorganic film and the upper inorganic film each have a higher refractive index at a side thereof in contact with the organic film, the closer to the other side not contacting the organic film, the higher the refractive index. The method according to claim 1,
The lower inorganic film includes a first lower inorganic film in contact with the organic light emitting element and a second lower inorganic film disposed on the first lower inorganic film,
Wherein the first lower inorganic film and the second lower inorganic film have different refractive indices. 5. The method of claim 4,
Wherein the second lower inorganic film has a lower refractive index than the first lower inorganic film. 5. The method of claim 4,
Wherein the organic film has a lower refractive index than the second lower inorganic film. 5. The method of claim 4,
Wherein a refractive index difference between the second lower inorganic film and the organic film is smaller than a refractive index difference between the first lower inorganic film and the organic film. 5. The method of claim 4,
Wherein the upper inorganic film includes a first upper inorganic film in contact with the organic film and a second upper inorganic film disposed on the first upper inorganic film. 9. The method of claim 8,
Wherein the second upper inorganic film has a refractive index higher than that of the first upper inorganic film. 9. The method of claim 8,
Wherein the organic film has a refractive index lower than that of the first upper inorganic film. 9. The method of claim 8,
Wherein a refractive index difference between the first upper inorganic film and the organic film is smaller than a refractive index difference between the second upper inorganic film and the organic film. 5. The method of claim 4,
Wherein the second lower inorganic film contains more nitrous oxide than the first lower inorganic film. 9. The method of claim 8,
Wherein the first upper inorganic film contains more nitrous oxide than the second upper inorganic film.

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