KR102431313B1 - Organic light emitting display device - Google Patents

Abstract

The present invention provides an organic light emitting display device capable of preventing a decrease in light efficiency, a thin film transistor disposed on a first substrate, an organic light emitting device disposed on the thin film transistor, and an encapsulation film covering the organic light emitting device The encapsulation film includes a lower inorganic film in contact with the organic light emitting device, an organic film disposed on the lower inorganic film, and an upper inorganic film covering the organic film, wherein each of the lower inorganic film and the upper inorganic film has a surface in contact with the organic film and an organic film. The other surfaces that are not in contact with the film have different refractive indices.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY DEVICE}

The present invention relates to an organic light emitting diode display.

As the information society develops, the demand for a display device for displaying an image is increasing in various forms. Accordingly, various display devices, such as a liquid crystal display (LCD), a plasma display panel (PDP), and an organic light emitting display (OLED), have recently been used.

Among display devices, an organic light emitting diode display is a self-emission type display device, which has superior viewing angle and contrast ratio compared to a liquid crystal display device (LCD). . In addition, the organic light emitting display device can be driven with a low direct current voltage, has a fast response speed, and particularly has advantages of low manufacturing cost.

The organic light emitting diode 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. In the organic light emitting diode display, when electrons generated from a cathode and holes generated from an anode are injected into an emission layer, the injected electrons and holes combine to generate excitons, and the generated excitons are in an excited state. It is a display device using the principle of emitting light while falling from the to the ground state.

However, the organic light emitting diode display includes an organic light emitting element in each of the pixels, but the organic light emitting element has a disadvantage in that the organic light emitting element is easily deteriorated by external factors such as external moisture and oxygen. To prevent this, the organic light emitting diode display forms an encapsulation layer covering the organic light emitting diode so that external moisture and oxygen do not permeate into the organic light emitting diode.

The encapsulation layer prevents oxygen or moisture from penetrating into the display area where the organic light emitting layer and the electrode are provided by sequentially stacking at least one inorganic layer and at least one organic layer.

In this case, the inorganic layer and the organic layer have different refractive indices. Accordingly, when light generated from the organic light emitting device is incident on the encapsulation layer, total internal reflection occurs while passing through the inorganic layer and the organic layer having different refractive indices in turn. Accordingly, the conventional organic light emitting display device has a problem in that light efficiency is reduced because light is lost due to an encapsulation film in which an inorganic film and an organic film having different refractive indices are stacked, and thus all light is not emitted to the outside.

SUMMARY OF THE INVENTION The present invention has been devised to solve the above-described problems, and an object of the present invention is to provide an organic light emitting diode display capable of preventing a decrease in light efficiency.

The present invention for achieving the above technical problem includes a thin film transistor disposed on a first substrate, an organic light emitting device disposed on the thin film transistor, and an encapsulation film covering the organic light emitting device, wherein the encapsulation film is a lower portion in contact with the organic light emitting device an inorganic film, an organic film disposed on the lower inorganic film, and an upper inorganic film covering the organic film, wherein each of the lower inorganic film and the upper inorganic film has a surface in contact with the organic film and the other surface not in contact with the organic film having different refractive indices An organic light emitting diode display is provided.

In the organic light emitting display device according to an embodiment of the present invention, since the difference in refractive index at the interface between the lower inorganic layer and the organic layer and the interface between the upper inorganic layer and the organic layer is small, light generated by the organic light emitting diode is emitted from the lower inorganic layer. Even if it passes through the organic layer and enters the organic layer and enters the upper inorganic layer through the organic layer, total internal reflection hardly occurs, thereby preventing a decrease in optical efficiency.

The effects obtainable in the present invention are not limited to the above-mentioned effects, and other effects not mentioned will be clearly understood by those of ordinary skill in the art to which the present invention belongs from the following description. .

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

The meaning of the terms described in this specification should be understood as follows.

The singular expression is to be understood as including the plural expression unless the context clearly defines otherwise, and the terms "first", "second", etc. are used to distinguish one element from another, The scope of rights should not be limited by these terms. It should be understood that terms such as “comprise” or “have” do not preclude the possibility of addition or existence of one or more other features or numbers, steps, operations, components, parts, or combinations thereof. The term “at least one” should be understood to include all possible combinations from one or more related items. For example, the meaning of "at least one of the first, second, and third items" means 2 of the first, second, and third items as well as each of the first, second, or third items. It means a combination of all items that can be presented from more than one. The term “on” is meant to include not only cases in which a certain component is formed directly on top of another component, but also a case in which a third component is interposed between these components.

Hereinafter, a preferred example of an organic light emitting diode display according to the present invention will be described in detail with reference to the accompanying drawings. In adding reference numerals to components of each drawing, the same components may have the same reference numerals as much as possible even though they are indicated in different drawings. In addition, in describing the present invention, when it is determined that a detailed description of a related known configuration or function may obscure the gist of the present invention, the detailed description may be omitted.

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

1 is a perspective view illustrating an organic light emitting diode display according to an exemplary embodiment, and FIG. 2 is a plan view illustrating a first substrate, a gate driver, a source driver 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 , and a source drive integrated circuit (hereinafter, referred to as “IC”). referred to) 13 , a flexible film 14 , a circuit board 15 , and a timing control unit 16 .

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

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 a region defined by an intersecting structure of gate lines and data lines.

Each of the pixels may include an organic light emitting diode including a thin film transistor, 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 diode according to the data voltage of the data line when a gate signal is input from the gate line using a thin film transistor. Accordingly, the organic light emitting device of each of the pixels may 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. 5 .

As shown in FIG. 2 , the display panel 11 may be divided into a display area DA in which pixels are formed to display an image and a non-display area NDA in which an image is not displayed. Gate lines, data lines, and pixels may be formed in the display area DA. The gate driver 12 and pads may be formed in the non-display area NDA.

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 by a gate driver in panel (GIP) method. Alternatively, the gate driving unit 12 is manufactured as a driving chip, mounted on a flexible film, and is a non-display area NDA on one or both sides of the display area DA of the display panel 11 in a tape automated bonding (TAB) method. may be attached to

The source drive IC 13 receives digital video data and a source control signal from the timing controller 16 . The source drive IC 13 converts digital video data into analog data voltages according to a source control signal and supplies them to data lines. When the source drive IC 13 is manufactured as a driving chip, it may be mounted on the flexible film 14 in a chip on film (COF) or chip on plastic (COP) 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 wires connecting the pads and the wires of the circuit board 15 may be formed on the flexible film 14 . The flexible film 14 is attached on the pads using an anisotropic conducting film, whereby the pads and wirings of the flexible film 14 can be connected.

The circuit board 15 may be attached to the flexible films 14 . A plurality of circuits implemented with driving chips may be mounted on the circuit board 15 . For example, the timing controller 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.

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

FIG. 3 is a cross-sectional view schematically illustrating one side of an organic light emitting diode display according to an example, and is a cross-sectional view taken along line II′ of FIG. 1 .

Referring to 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 , and an organic It may include 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) method, 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 emission layer through the hole transport layer and the electron transport layer, respectively, and combine with each other in the emission layer to emit light. Since pixels are provided in the region in which the organic light emitting device layer 200 is disposed, the region in which the organic light emitting device layer 200 is disposed may be defined as a display area. A peripheral area of the display area may be defined as a non-display area.

The encapsulation layer 300 is disposed on the organic light emitting device layer 200 . The encapsulation layer 300 serves to prevent oxygen or moisture from penetrating into the organic light emitting device layer 200 . The encapsulation layer 300 may include at least one organic layer and an inorganic layer.

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

4 is a plan view schematically illustrating a first substrate according to an exemplary embodiment, and FIG. 5 is a cross-sectional view of an organic light emitting diode display according to an exemplary embodiment, taken along line II-II′ of FIG. 4 .

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 encapsulation layer 300 are formed in the display area 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 layer 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, which is vulnerable to moisture permeation. do. One surface of the first substrate S1 may be a surface facing the second substrate S2 . The buffer layer 110 may be formed of a plurality of inorganic layers alternately stacked. For example, the buffer layer 110 may be formed as a multilayer in which one or more inorganic layers of a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), and SiON are alternately stacked. The buffer layer 110 may be omitted.

The thin film transistor 120 is disposed on the buffer layer 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 illustrates that the thin film transistor 120 is formed in a top gate (top gate) method in which the gate electrode 122 is positioned on the active layer 121 , but it should be noted that the present invention is not limited thereto. That is, the thin film transistors 120 have a lower gate (bottom gate) method in which the gate electrode 122 is positioned under the active layer 121 or the gate electrode 122 is positioned above and below the active layer 121 . It may be formed in a double gate method in which all of them are located.

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 blocking layer for blocking external light incident to 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 layer 130 may be formed of an inorganic layer, for example, a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), or a multilayer 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 include any one of molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), neodymium (Nd), and copper (Cu). It may be formed as a single layer or multiple layers made of one or an alloy thereof.

The interlayer insulating layer 140 may be disposed on the gate electrode 122 and the gate line. The interlayer insulating layer 140 may be formed of an inorganic layer, for example, a silicon oxide layer (SiOx), a silicon nitride layer (SiNx), or a multilayer 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 penetrating the gate insulating layer 130 and the interlayer insulating layer 140 . The source electrode 123 , the drain electrode 124 , and the data line 125 are molybdenum (Mo), aluminum (Al), chromium (Cr), gold (Au), titanium (Ti), nickel (Ni), and neodymium. It may be formed as a single layer or multiple layers made of any one of (Nd) and copper (Cu) or an alloy thereof.

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

The planarization layer 150 for flattening a step caused by the thin film transistor 120 may be disposed on the interlayer insulating layer 140 . The planarization film 150 may be formed of an organic film such as an acrylic 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 .

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 a contact hole penetrating the planarization layer 150 . The first electrode 211 has a stacked structure of aluminum and titanium (Ti/Al/Ti), a stacked structure of aluminum and ITO (ITO/Al/ITO), an APC alloy, and a stacked structure of an APC alloy and ITO (ITO/APC). /ITO) may be formed of a metal material having a high reflectance. 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 disposed to cover the edge of the first electrode 211 on the planarization layer 150 to partition the pixels. That is, the bank 220 serves as a pixel defining layer defining pixels. The bank 220 may be formed of an organic layer such as an acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin. .

The organic emission layer 212 is disposed on the first electrode 211 and the bank 220 . The organic emission 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 emission layer through the hole transport layer and the electron transport layer, respectively, and combine with each other in the emission layer to emit light.

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

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

The second electrode 213 is disposed on the organic emission layer 212 . When the organic light emitting diode display has a top emission structure, the second electrode 213 may be formed of a transparent metal material (TCO), such as ITO, IZO, or magnesium (Mg) capable of transmitting light. ), silver (Ag), or a semi-transmissive conductive material such as an alloy of magnesium (Mg) and silver (Ag). A capping layer may be disposed on the second electrode 213 .

The encapsulation layer 300 may be disposed on the organic light emitting device layer 200 to extend not only to the display area DA of the first substrate S1 but also to the non-display area NDA. The encapsulation layer 300 according to an embodiment of the present invention includes an encapsulation film 310 and a dam (DAM).

The encapsulation layer 310 is disposed on the bank 220 and is disposed to cover the display area DA, and serves to prevent oxygen or moisture from penetrating into the organic light emitting layer 212 and the second electrode 213 . do. To this end, the encapsulation layer 310 may include at least one inorganic layer and at least one organic layer.

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

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

The upper inorganic layer 313 may be disposed on the organic layer 312 . The upper inorganic layer 313 may be disposed to cover the organic layer 312 . Specifically, the upper inorganic layer 313 covers the organic layer 312 in the display area DA, and extends to the non-display area NDA to cover the dam DAM and the lower inorganic layer 311 . can In the upper inorganic layer 313 , defects or steps do not occur due to the organic layer 312 disposed below, and thus, a path through which external moisture permeates into the device is not formed. ) to prevent deterioration of reliability and quality.

Each of the lower and upper inorganic layers 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 acrylic resin, an epoxy resin, a phenolic resin, a polyamide resin, or a polyimide resin.

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

In order to solve this problem, in the organic light emitting display device according to an embodiment of the present invention, a difference in refractive index at the interface between the lower and upper inorganic layers 311 and 313 of the encapsulation layer 310 and the organic layer 312 is in contact. reduces the

More specifically, the refractive index of the lower inorganic film 311 of the encapsulation film 310 according to an embodiment of the present invention is gradually decreased from one surface in contact with the second electrode 213 to the other surface in contact with the organic film 312 . . Accordingly, in the organic light emitting diode display according to an embodiment of the present invention, since the difference in refractive index at the interface between the lower inorganic layer 311 and the organic layer 312 is small, the light generated by the organic light emitting diode 210 is lowered. Even if it passes through the inorganic layer 311 and is incident on the organic layer 312 , total internal reflection hardly occurs.

In addition, the refractive index of the upper inorganic film 313 of the encapsulation film 310 according to an embodiment of the present invention is gradually increased from one surface in contact with the organic film 312 to the other surface not in contact with the organic film 312 . Accordingly, in the organic light emitting diode display according to the exemplary embodiment of the present invention, since the difference in refractive index at the interface between the upper inorganic layer 313 and the organic layer 312 is small, the light generated by the organic light emitting diode 210 is organic. Even if it passes through the film 312 and is incident on the upper inorganic film 313 , total internal reflection hardly occurs.

Accordingly, in the organic light emitting display device according to an embodiment of the present invention, by gradually changing the refractive indices of the lower and upper inorganic layers 311 and 313 , light emitted from the organic light emitting device 210 is emitted from the lower and upper inorganic layers ( Even if it passes through 311 and 313 and the organic layer 312 sequentially, a loss due to total internal reflection is reduced, thereby preventing a decrease in light efficiency.

The dam DAM is disposed in the non-display area NDA to block the flow of the organic layer 312 constituting the encapsulation layer 310 . More specifically, the dam DAM may be disposed to surround the periphery of the display area DA to block the flow of the organic layer 312 constituting the encapsulation layer 310 . In addition, the dam DAM is disposed in the non-display area NDA to prevent the organic layer 312 constituting the encapsulation layer 310 from penetrating the pad (not shown) exposed by the contact hole. can block the flow of Accordingly, the dam DAM may prevent the organic layer 312 from being exposed to the outside of the display device or from penetrating the pad.

The dam (DAM) according to an example 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 to surround the periphery of the display area DA to primarily block the flow of the organic layer 312 constituting the encapsulation layer 310 . can In addition, the internal dam ID is disposed between the display area DA and the pad area PA to primarily prevent the organic layer 312 from penetrating the exposed pad (not shown). can be blocked with

The outer dam OD is disposed to surround the outer periphery of the inner dam ID, and is spaced apart from each other and disposed side by side. At this time, the interval between the outer dam (OD) and the inner dam (ID) may have a very narrow interval of about 30 ~ 40um, but is not limited thereto. The outer dam OD may secondarily block the organic layer 312 overflowing to the outside of the inner dam ID. Also, the height of the outer dam OD may be higher than the height of the inner dam ID. Accordingly, the inner dam ID and the outer dam OD may more effectively block the organic layer 312 from being exposed to the outside of the organic light emitting diode display 10 or from encroaching on the exposed pad.

The inner dam ID according to an embodiment of the present invention includes a first inner dam ID1 disposed on the interlayer insulating layer 140 , and a second inner dam ID2 disposed on the first inner dam ID1 . may include. In addition, the external dam OD according to an embodiment of the present invention includes a first external dam OD1 disposed on the interlayer insulating film 140 , and a second external dam OD2 disposed on the first external dam OD1 . ), and a third external dam OD3 disposed on the second external dam OD2. In this case, the first external dam OD1 may be formed of the same material as the planarization film 150 . In addition, the first inner dam ID1 and the second outer dam OD2 may have the same material and may be formed of the same material as the bank 220 . In addition, the second inner dam ID2 and the third outer dam OD3 may have the same material and may be formed of the same material as a spacer (not shown) disposed on the bank 220 . Accordingly, the dam DAM according to an embodiment of the present invention may be simultaneously formed when the planarization layer 150 , the bank 220 , and the spacer are formed, and may be formed without a separate additional process.

As described above, in the organic light emitting diode display according to an embodiment of the present invention, the light emitted from the organic light emitting device 210 is emitted from the lower and upper inorganic layers 311 and 313 by gradually changing the refractive index inside the encapsulation layer 310 . ) and the organic layer 312 in turn, the loss due to total internal reflection is reduced, and thus light efficiency can be prevented from being lowered.

6 is a cross-sectional view of an encapsulation film according to a first embodiment of the present invention, and is an enlarged view of portion A of FIG. 5 .

Referring to FIG. 6 , the encapsulation 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 layer 311 according to the first embodiment of the present invention includes a first lower inorganic layer 311a in contact with the organic light emitting device 210 and a second lower inorganic layer disposed on the first lower inorganic layer 311a. a film 311b.

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

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

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

That is, the refractive index of the lower inorganic film 311 of the encapsulation film 310 according to the first embodiment of the present invention is gradually decreased from one surface in contact with the second electrode 213 to the other surface in contact with the organic film 312 . Accordingly, in the organic light emitting diode display according to the first embodiment of the present invention, since the difference in refractive index at the interface between the lower inorganic layer 311 and the organic layer 312 is small, the light generated by the organic light emitting diode 210 is Even if it passes through the lower inorganic layer 311 and is incident on the organic layer 312 , total internal reflection hardly occurs.

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 disposed on the first upper inorganic film 313a . (313b).

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

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

In this case, the organic layer 312 according to the first embodiment of the present invention has a lower refractive index than that of the first upper inorganic layer 313a. Also, a difference in refractive index between the first upper inorganic layer 313a and the organic layer 312 is smaller than a difference in refractive index between the second upper inorganic layer 313b and the organic layer 312 . That is, the refractive index of the upper inorganic film 313 of the encapsulation film 310 according to the first embodiment of the present invention is gradually increased from one surface in contact with the organic film 312 to the other surface not in contact with the organic film 312 . .

Accordingly, in the organic light emitting diode display according to the first embodiment of the present invention, since the difference in refractive index at the interface between the upper inorganic layer 313 and the organic layer 312 is small, the light generated by the organic light emitting diode 210 is Even if it passes through the organic layer 312 and is incident on the upper inorganic layer 313 , total internal reflection hardly occurs.

As described above, in the organic light emitting display device according to the first exemplary embodiment of the present invention, the ratio of nitrous oxide (N2O) in the lower and upper inorganic layers 311 and 313 is gradually changed, or silicon nitride (SiNx) and silicon oxynite are By depositing a multi-layered inorganic layer made of Ride (SiON), the refractive indices of the lower and upper inorganic layers 311 and 313 may be gradually changed. Accordingly, in the organic light emitting diode display according to the first embodiment of the present invention, even though light emitted from the organic light emitting diode 210 passes through the lower and upper inorganic layers 311 and 313 and the organic layer 312 in sequence, total internal reflection The loss due to the decrease is reduced, and accordingly, it is possible to prevent deterioration of the light efficiency.

7 is a cross-sectional view of an encapsulation film according to a second exemplary embodiment of the present invention, and is an enlarged view of portion A of FIG. 5 .

The encapsulation film 310 illustrated in FIG. 7 is the same as the encapsulation film 310 described with reference to FIG. 6 , except that the third lower inorganic film 311c and the third upper inorganic film 313c are added. Accordingly, in the following description, only the third lower inorganic layer 311c and the third upper inorganic layer 313c will be described, and repeated descriptions of the same configuration will be omitted.

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

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

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

The organic layer 312 has a lower refractive index than the third lower inorganic layer 311c. The organic layer 312 according to an example may have a refractive index of 1.5. Accordingly, in the encapsulation film 310 according to the second embodiment of the present invention, the difference in refractive index between the third lower inorganic film 311c and the organic film 312 is the first lower inorganic film 311a or the second lower inorganic film ( 311b) and the difference in refractive index between the organic layer 312 is smaller.

That is, the refractive index of the lower inorganic film 311 of the encapsulation film 310 according to the second embodiment of the present invention is gradually decreased from one surface in contact with the second electrode 213 to the other surface in contact with the organic film 312 . Accordingly, in the organic light emitting display device according to the second exemplary embodiment of the present invention, since the difference in refractive index at the interface between the lower inorganic layer 311 and the organic layer 312 is small, the light generated by the organic light emitting device 210 is Even if it passes through the lower inorganic layer 311 and is incident on the organic layer 312 , total internal reflection hardly occurs.

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 , and a second upper inorganic film 313a disposed on the first upper inorganic film 313a. 313b), and a third upper inorganic layer 313c disposed on the second upper inorganic layer 313b.

The third upper inorganic layer 313c is disposed on the second upper inorganic layer 313b. The third upper inorganic layer 313c according to the second embodiment of the present invention may contain a smaller amount of nitrous oxide (N2O) than the second upper inorganic layer 313b or may not contain nitrous oxide (N2O). , silicon nitride (SiNx). As the amount of nitrous oxide (N2O) included in the inorganic film increases, the refractive index of the inorganic film decreases. Accordingly, the third upper inorganic layer 313c according to the second exemplary embodiment of the present invention has a refractive index different from that of the second upper inorganic layer 313b and the first upper inorganic layer 313a disposed thereunder. More specifically, the third upper inorganic layer 313c according to the second embodiment of the present invention has a higher refractive index than the second upper inorganic layer 313b and the first upper inorganic layer 313a. According to an example, the third upper inorganic layer 313c may have a refractive index of about 1.85, and the second upper inorganic layer 313b may have a refractive index of about 1.75 to about 1.84.

In this case, the organic layer 312 according to the second embodiment of the present invention has a lower refractive index than that of the first upper inorganic layer 313a. Also, a difference in refractive index between the second upper inorganic layer 313b and the organic layer 312 is smaller than a difference in refractive index between the third upper inorganic layer 313c and the organic layer 312 . That is, the refractive index of the upper inorganic film 313 of the encapsulation film 310 according to the second embodiment of the present invention is gradually increased from one surface in contact with the organic film 312 to the other surface not in contact with the organic film 312 . .

Accordingly, in the organic light emitting display device according to the second exemplary embodiment of the present invention, since the difference in refractive index at the interface between the upper inorganic layer 313 and the organic layer 312 is small, the light generated by the organic light emitting device 210 is Even if it passes through the organic layer 312 and is incident on the upper inorganic layer 313 , total internal reflection hardly occurs.

As described above, in the organic light emitting display device according to the second embodiment of the present invention, the ratio of nitrous oxide (N2O) is gradually changed and deposited on the lower and upper inorganic layers 311 and 313, or silicon nitride (SiNx) and silicon are deposited. By depositing a multi-layered inorganic film made of oxynitride (SiON), the refractive indices of the lower and upper inorganic films 311 and 313 may be gradually changed. Accordingly, in the organic light emitting display device according to the second exemplary embodiment of the present invention, even though light emitted from the organic light emitting diode 210 passes through the lower and upper inorganic layers 311 and 313 and the organic layer 312 in sequence, total internal reflection The loss due to the decrease is reduced, and accordingly, it is possible to prevent deterioration of the light efficiency.

Meanwhile, in the organic light emitting display device according to an embodiment of the present invention, as the number of layers having different refractive indices constituting the lower inorganic layer 311 and the upper inorganic layer 313 increases, the difference in refractive index for each interface may be reduced. Therefore, loss due to total internal reflection can be greatly reduced, and accordingly, it is possible to prevent deterioration of optical efficiency.

8A and 8B are graphs of light transmittance of an organic light emitting diode display according to a related art and a second exemplary embodiment of the present invention.

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

Referring to FIG. 8A , the conventional organic light emitting diode display has a very low light transmittance of about 77.5% to 91.5%, about 77.5% when the light transmittance is the lowest, and is very high, about 91.5% even when the light transmittance is the highest. not. Accordingly, it can be seen that, in the conventional organic light emitting display device, light is lost due to the encapsulation film in which the single-layer inorganic film is stacked, and thus all light is not emitted to the outside.

Referring to FIG. 8B , in the organic light emitting diode display according to the second exemplary embodiment of the present invention, the light transmittance is about 90% to 100%, and the light transmittance is about 90% when the light transmittance is the lowest. It is similar, and when the light transmittance is the highest, it is very high, about 100%. Accordingly, in the organic light emitting display device according to the second exemplary embodiment of the present invention, most of the light emitted from the organic light emitting device 210 is transmitted out of the encapsulation layer 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 more detail with reference to the accompanying drawings, the present invention is not necessarily limited to these embodiments, and various modifications may be made within the scope without departing from the technical spirit of the present invention. . Therefore, the embodiments disclosed in the present invention are not intended to limit the technical spirit of the present invention, but to explain, and the scope of the technical spirit of the present invention is not limited by these embodiments. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive. The protection scope of the present invention should be construed by the claims, and all technical ideas within the scope equivalent thereto should be construed 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 controller 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 device layer
210: organic light emitting device 211: first electrode
212: organic light emitting layer 213: second electrode
220: bank 300: encapsulation layer
310: encapsulation film 311: lower inorganic film
312: organic layer 313: upper inorganic layer
DAM: Dam ID: Inner Dam
OD: external dam

Claims (13)

a thin film transistor disposed in a display area on the first substrate;
an organic light emitting device disposed on the thin film transistor;
an encapsulation film covering the organic light emitting device; and
a dam disposed in a non-display area outside the display area;
The encapsulant is
a lower inorganic layer in contact with the organic light emitting device;
an organic layer disposed on the lower inorganic layer; and
and an upper inorganic film covering the organic film,
Each of the lower inorganic film and the upper inorganic film has a surface in contact with the organic film and the other surface not in contact with the organic film having different refractive indices,
The upper inorganic layer is in contact with the lower inorganic layer on the dam. The method of claim 1,
In each of the lower inorganic layer and the upper inorganic layer, a refractive index of one surface contacting the organic layer is lower than a refractive index of the other surface not in contact with the organic layer. The method of claim 1,
Each of the lower inorganic layer and the upper inorganic layer has a refractive index that increases from one surface contacting the organic layer to the other surface not in contact with the organic layer. The method of claim 1,
The lower inorganic layer includes a first lower inorganic layer in contact with the organic light emitting device and a second lower inorganic layer disposed on the first lower inorganic layer,
The first lower inorganic layer and the second lower inorganic layer have different refractive indices. 5. The method of claim 4,
The second lower inorganic layer has a refractive index lower than that of the first lower inorganic layer. 5. The method of claim 4,
The organic layer has a lower refractive index than that of the second lower inorganic layer. 5. The method of claim 4,
A difference in refractive index between the second lower inorganic layer and the organic layer is smaller than a difference in refractive index between the first lower inorganic layer and the organic layer. 5. The method of claim 4,
The upper inorganic layer may include a first upper inorganic layer in contact with the organic layer and a second upper inorganic layer disposed on the first upper inorganic layer. 9. The method of claim 8,
The second upper inorganic layer has a refractive index higher than that of the first upper inorganic layer. 9. The method of claim 8,
The organic layer has a lower refractive index than that of the first upper inorganic layer. 9. The method of claim 8,
A difference in refractive index between the first upper inorganic layer and the organic layer is smaller than a difference in refractive index between the second upper inorganic layer and the organic layer. 5. The method of claim 4,
The second lower inorganic layer includes more nitrous oxide than the first lower inorganic layer. 9. The method of claim 8,
The first upper inorganic layer includes more nitrous oxide than the second upper inorganic layer.

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