KR101564629B1 - Organic electro-luminescence device - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device including a heat dissipating member for radiating heat from the organic electroluminescent device.

The present invention relates to a method of manufacturing an organic light emitting display, which comprises encapsulating a first substrate and a second substrate, on which a driving thin film transistor and an organic light emitting diode are formed, through a protective layer having adhesion, And is configured to have a conductivity.

As a result, it is possible to effectively dissipate the heat of the high temperature generated from the OLED, while maintaining a lightweight and thin appearance.

Organic electroluminescent device, heat dissipation, encapsulation

Description

[0001] The present invention relates to an organic electroluminescent device,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic electroluminescent device, and more particularly, to an organic electroluminescent device including a heat dissipating member for radiating heat from the organic electroluminescent device.

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

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

In addition, it has a better viewing angle and contrast ratio than liquid crystal display devices, is advantageous in terms of power consumption, can be driven by DC low voltage, has a fast response speed, is resistant to external impacts due to its solid internal components, It has wide advantages.

Particularly, since the manufacturing process is simple, it is advantageous in that the production cost can be saved more than the conventional liquid crystal display device.

OLEDs having such characteristics are largely divided into a passive matrix type and an active matrix type. In a passive matrix type, a device is formed in a matrix form while crossing signal lines, whereas an active matrix type is a pixel A thin film transistor which is a switching element for on / off switching, a driving thin film transistor for flowing a current, and a capacitor for holding a voltage for one frame in a driving thin film transistor are provided for each pixel.

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

1 schematically shows a cross section of a general active matrix type OLED, wherein the OLED is a bottom emission type.

As shown, the OLED 10 comprises a first substrate 1 and a second substrate 2 facing the first substrate 1, and the first and second substrates 1, And the edge portion of the sealant 20 is sealed and adhered thereto.

A driving TFT DTr is formed on the first substrate 1 for each pixel region P and a first electrode 11 constituting the organic light emitting diode E, An organic light emitting layer 13, and a second electrode 15 are sequentially formed. The first electrode 11 is electrically connected to the driving thin film transistor DTr.

In such a case, the first electrode 11 may be made of a transparent conductive material, and the second electrode 15 may be made of an opaque conductive material. Accordingly, light emitted from the organic light emitting layer 13 is emitted toward the first electrode 11.

On the inner surface of the second substrate 2, a moisture absorbent 17 for removing moisture permeated from the outside is formed.

On the other hand, the OLED 10 has a disadvantage in that the lifetime of the OLED 10 is drastically reduced due to heat generated during driving and deterioration of the driving thin film transistor DTr.

Recently, it has been proposed to form a heat dissipating plate 30 such as a fan or a heat pipe in an apparatus for modifying the OLED 10 in order to solve the above disadvantage. However, There is a certain amount of effect, but the effect on the price is insignificant and the OLED 10 is damaged during the installation process.

That is, the heat sink 30 is attached to the outer surface of the second substrate 2 of the OLED 10 through a lamination process, wherein the laminating process is performed by placing the heat sink 30 on the second substrate 2, The heat sink 30 and the second substrate 2 are attached to each other while being pressed by a laminator.

At this time, bending of the second substrate 2 is caused in the process of pressing the heat radiating plate 30 with the laminator, and the moisture absorbent 17 formed on the inner surface of the second substrate 2 passes through the first substrate 2, (C, D) of the organic electroluminescent diode (E) as shown in the attached photograph of FIG. 2 by bringing the organic electroluminescent diode (E) into contact with the organic electroluminescent diode (E) formed on the substrate (1).

In addition, such a heat dissipation structure causes a problem that is contrary to the trend of lightness and thinness of the display device.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is a first object of the present invention to effectively dissipate an OLED.

Another object of the present invention is to provide a lightweight and thin OLED.

According to an aspect of the present invention, there is provided a liquid crystal display comprising: a first substrate on which a driving thin film transistor and an organic light emitting diode are formed; And a second substrate spaced apart from the first substrate with a protective layer interposed therebetween, the protective layer including a heat dissipating member.

Wherein the heat dissipation member is a heat dissipation film adhered to the inner surface of the second substrate and the heat dissipation film is formed of a metal such as graphite or aluminum (Al), copper (Cu), nickel (Ni) The particles are coated.

Here, the thickness of the heat radiation film is 50% or more of the thickness of the protective layer.

In addition, the size of the heat dissipation film is larger than the active area which is flat in an image is implemented, is smaller than the size of the protection layer, the radiation member is graphite particles, silicon oxide (SiO _2), aluminum oxide (Al ₂ O _3), one of titanium oxide (TiO _2), zinc oxide (ZnO), etc. of the non-metallic particles, or aluminum (Al), copper (selected one of metal particles such as Cu), nickel (Ni), silver (Ag), the protective layer Is thermally conductive through the heat radiation member.

At this time, the protective layer covers the driving thin film transistor and the organic light emitting diode, and the protective layer includes barium oxide (BaO) or calcium oxide (CaO) which is hydrophobic or absorbs moisture.

In addition, the second substrate is a metal foil.

As described above, according to the present invention, a heat radiation film is provided inside the protective layer that encapsulates the first and second substrates, or the protective layer itself is made to have thermal conductivity, Thereby effectively dissipating the heat of the heat exchanger.

In addition, the OLED according to the present invention is excellent in heat dissipation effect and can maintain a lightweight and thin shape compared to a conventional fan or a heat pipe.

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

FIG. 3 is a cross-sectional view schematically showing an OLED according to the first embodiment of the present invention, and FIG. 4 is an enlarged cross-sectional view of a part of FIG.

Meanwhile, the OLED 100 is divided into a top emission type and a bottom emission type according to the transmission direction of the emitted light. Hereinafter, the bottom emission type will be described as an example of the present invention.

The OLED 100 according to the present invention includes a first substrate 101 on which a driving thin film transistor DTr and an organic light emitting diode E are formed and a second substrate 102 for encapsulation Respectively.

A semiconductor layer 201 is formed on the first substrate 101. The semiconductor layer 201 is made of silicon and has a central portion on both sides of the active region 201a and the active region 201a forming a channel. And doped source and drain regions 201b and 201c.

A gate insulating layer 203 is formed on the semiconductor layer 201.

A gate electrode 205 corresponding to the semiconductor layer 201a and a gate wiring extending in one direction although not shown in the figure are formed on the gate insulating film 203.

A first interlayer insulating film 207a and a gate insulating film 203 under the first interlayer insulating film 207a are formed on the entire upper surface of the gate electrode 205 and the gate wiring (not shown) And first and second semiconductor layer contact holes 209a and 209b that respectively expose the source and drain regions 201b and 201c on both sides.

Next, upper portions of the first interlayer insulating film 207a including the first and second semiconductor layer contact holes 209a and 209b are separated from each other by the source and the drain, which are exposed through the first and second semiconductor layer contact holes 209a and 209b, And source and drain electrodes 211 and 213 which are in contact with the drain regions 201b and 201c, respectively.

And a drain contact hole 215 exposing the drain electrode 213 over the first interlayer insulating film 207a exposed between the source and drain electrodes 211 and 213 and the two electrodes 211 and 213. [ An insulating film 207b is formed.

A semiconductor layer 201 including source and drain electrodes 211 and 213 and source and drain regions 201b and 201c in contact with the electrodes 211 and 213; The gate insulating film 203 and the gate electrode 205 constitute a driving thin film transistor DTr.

The driving thin film transistor DTr includes a polysilicon semiconductor layer and is shown as a top gate type. As a modification thereof, the driving thin film transistor DTr may be a bottom gate made of amorphous silicon (107a, 107b) Or a bottom gate type.

The first electrode 111, the organic light emitting layer 113 and the second electrode 115 constituting the organic electroluminescent diode E are sequentially formed on the second interlayer insulating film 207b, Respectively.

The first and second electrodes 111 and 115 and the organic light emitting layer 113 formed therebetween form an organic light emitting diode E.

The first electrode 111 is connected to the drain electrode 213 of the driving thin film transistor DTr.

In such a case, the first electrode 111 may be formed of a transparent conductive material having a relatively large work function value such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) As shown in Fig.

The second electrode 115 may be made of a non-transparent conductive material to serve as a cathode electrode.

The second electrode 115 may be formed of a metal material having a relatively low work function value as compared with the first electrode 111 such as aluminum (Al), aluminum alloy (AlNd), silver (Ag), magnesium (Mg) Gold (Au), and aluminum magnesium alloy (AlMg).

Accordingly, the light emitted from the organic light emitting layer 113 is driven by the lower light emitting method, which is emitted toward the first electrode 111.

Here, the organic light emitting layer 113 may be a single layer made of a light emitting material. In order to increase the light emitting efficiency, a hole injection layer, a hole transporting layer, an emitting material layer, And may be composed of multiple layers of an electron transporting layer and an electron injection layer.

A bank 221 is positioned between the first electrodes 111 formed for each pixel region P.

That is, the banks 221 are formed in the matrix type of the lattice structure as a whole on the first substrate 101, and the first electrodes 111 are formed in the pixel regions P with the banks 221 as boundary portions for the respective pixel regions P, Are formed in a separated structure.

When a predetermined voltage is applied to the first electrode 111 and the second electrode 115 according to a selected color signal, the OLED 100 emits a positive voltage to the first electrode 111 and a second electrode 115 from the second electrode 115 The provided electrons are transported to the organic light emitting layer 113 to form an exciton. When the excitons transit from the excited state to the ground state, light is emitted and emitted in the form of visible light.

At this time, the emitted light passes through the transparent first electrode 111 and exits to the outside, so that the OLED 100 realizes an arbitrary image.

The second substrate 102 is provided on the driving TFT DTr and the organic light emitting diode E so that the first and second substrates 101 and 102 are electrically connected to each other through the protective layer 120 And they are separated from each other and joined together.

Thereby, the OLED 100 is encapsulated.

At this time, the protective layer 120 may include barium oxide (BaO) or calcium oxide (CaO) having a hydrophobic property or a moisture absorption property therein. Therefore, even if moisture permeates into the protective layer 120 due to hydrophobicity of the protective layer 120 itself, it is possible to prevent contact with the organic light emitting layer 113 due to moisture absorption property .

In addition, since the protection layer 120 is directly formed on the organic electroluminescent diode E, the conventional seal pattern (20 in FIG. 1) can be omitted.

Accordingly, the OLED 100 is made of a polymeric material and has a problem that a pollutant such as moisture or gas penetrates into the OLED 100 from the outside through the seal pattern (20 in FIG. 1) as the temperature is heated or stored for a long time. .

In the OLED 100 of the present invention, even if a pressure such as pushing is applied from outside, the OLED 100 is not pressed by the protection layer 120, and the first and second It is possible to prevent cracks of the electrodes 111 and 115 or the driving thin film transistor DTr.

Accordingly, it is possible to prevent a problem such as a defect in a dark spot, thereby preventing a problem of uneven brightness and image characteristics.

In particular, the heat dissipating film 200 for efficiently designing the heat dissipation of the OLED 100 is attached to the inner surface of the second substrate 102 of the present invention through an adhesive material (not shown) such as a double-sided tape .

Therefore, the OLED 100 of the present invention has an efficient heat dissipation design through the heat dissipation film 200.

Accordingly, heat generated from the inside of the OLED 100 is effectively emitted to the outside, and at the same time, the light-weight and thin OLED 100 are provided.

The specific area of the OLED 100 is about 80 to 90 degrees Celsius due to heat generated when the driving thin film transistor DTr and the organic light emitting diode E are deteriorated during operation of the OLED 100. [ The temperature rises. The lifetime of the OLED 100 is drastically reduced due to the concentrated high-temperature heat.

However, since the OLED 100 according to the present invention has the heat dissipation film 200 attached to the inner surface of the second substrate 102, the high temperature heat generated from the inside of the OLED 100 is focused on a specific region of the OLED 100 So that the heat spreading effect is obtained.

Here, the heat dissipation film 200 may be formed by coating a base material made of polyethylene terephthalate with a material having a high thermal conductivity. For example, graphite may be vapor deposited or sputtered on a base film under high vacuum .

In this case, when the heat radiating film 200 is formed of a graphite material, it is preferable that the heat radiating film 200 has a structure in which a layered graphite layer is laminated, and the laminated graphite layer is formed by foaming graphite having a flat structure and rolling it at a high pressure The heat radiation film 200 is formed.

At this time, since the heat dissipation film 200 made of graphite is black, the heat absorption rate is increased, and the heat dissipation film 200 has high heat conduction characteristics.

Accordingly, heat transmitted to the heat-radiating film 200 is effectively diffused to the entire heat-radiating film 200.

Or metal particles such as aluminum (Al), copper (Cu), nickel (Ni), silver (Ag) or the like having excellent thermal conductivity in addition to graphite or materials such as rubber series or acrylic series.

At this time, when the heat dissipating film 200 is formed of aluminum (Al), it is preferable that aluminum has a purity of 99.5%, and it is preferable that a black oxide film is formed on the surface through anodizing treatment .

5, the heat-radiating film 200 is formed so as to cover all of the active area A / A where the image of the OLED 100 is implemented. At this time, the heat- (D) of 0.05 to 0.1 mm or more than the width (A / A).

It is preferable that the size of the heat dissipation film 200 is smaller than the size of the protection layer 120 so that the edge of the protection layer 120 is exposed. This prevents the contaminants such as moisture and gas from penetrating into the OLED 100 from outside by the exposed protective layer 120 and prevents the first and second substrates 101 and 102 from adhering to each other .

The thickness h2 of the heat dissipation film 200 is preferably 50% or more of the thickness h1 of the protective layer 120, that is, the thickness between the first and second substrates 101 and 102 This is because the driving thin film transistor DTr formed on the first substrate 101 and the heat radiating film 200 attached to the inner surface of the second substrate 102 generate heat generated from the organic electroluminescent diode E So that it can be quickly conducted.

For example, when the thickness h1 of the protective layer 120 is set to 5 m or more, it has an excellent effect of preventing penetration of contaminants such as moisture and gas from the outside into the OLED 100, At this time, it is preferable that the thickness of the heat dissipation film 200 is 3 mu m or more.

As described above, by attaching the heat radiation film 200 to the inner surface of the second substrate 102, the heat generated from the inside of the OLED 100 is dissipated to the outside more effectively, and the lifetime of the OLED 100 is drastically reduced Thereby preventing the problem.

Particularly, by attaching the heat dissipating film 200 to the inner surface of the second substrate 102, it is possible to prevent the heat dissipation of the conventional OLED 100, such as a fan (not shown) or a heat pipe (not shown) It is possible to realize a lightweight and thin shape as compared with the construction of the heat radiating plate (30 of FIG. 1).

Also, the problem that the organic light emitting diode E is damaged (C, D in FIG. 2) through the lamination process proceeding to attach the heat sink (30 in FIG. 1) to the OLED 100 is prevented.

The first substrate 101 may be formed of glass, plastic, stainless steel, or the like. Since the OLED 100 of the present invention is a bottom emission type OLED 100, It is preferable to use a material.

The second substrate 102 may be formed of glass or a metal foil or the like. The OLED 100 of the present invention may be formed by forming a second substrate 102 from a metal foil to form an OLED 100 Is further improved.

That is, the OLED 100 of the present invention has a more efficient heat dissipation design through the heat dissipating film 200 and the second substrate 102 made of a metal foil.

By forming the second substrate 102 with the metal foil, the heat dissipation characteristics of the OLED 100 can be further improved. In addition to the effect of forming the second substrate 102 with glass, And the overall thickness of the OLED 100 can be reduced. In addition, the durability of the OLED 100 itself can be improved in spite of the reduction in the thickness of the OLED 100.

At this time, it is preferable that the thermal conductivity of the second substrate 102 made of the metal foil is the same as the thermal conductivity of the first substrate 101 or less than 10 10 ^-2 / ° C.

This is because when the second substrate 102 is formed of a metal foil, the second substrate (metal foil) 102 and the first substrate (glass) 101 are formed of different materials, Curl or bending due to a difference in thermal expansion rate between the first and second substrates 102 may occur.

FIG. 6 is a cross-sectional view schematically showing an OLED according to a second embodiment of the present invention, and FIG. 7 is an enlarged cross-sectional view of part of FIG.

The OLED of the bottom emission type will be described as an example and the same reference numerals are used for the same parts that have the same functions as those of FIGS. 3 and 4 of the first embodiment described above in order to avoid redundant description. Let's take a look at the characteristic features of the above.

The OLED 100 according to the present invention includes a first substrate 101 on which a driving thin film transistor DTr and an organic light emitting diode E are formed and a second substrate 102 for encapsulation Respectively.

A semiconductor layer 201 including source and drain electrodes 211 and 213 and source and drain regions 201b and 201c which are in contact with the electrodes 211 and 213 and a semiconductor layer 201 including source and drain electrodes 201b and 201c are formed on a first substrate 101, The driving thin film transistor DTr is formed in the gate insulating film 203 and the gate electrode 205 formed on the upper substrate 201,

Reference numerals 201a and 201b denote active regions of the semiconductor layer 201. Reference numerals 207a and 207b denote first and second interlayer insulating films. Reference numerals 209a and 209b denote first and second interlayer insulating films, respectively, which expose the source and drain regions 201b and 201c, 2 semiconductor layer contact hole, and 215 is a drain contact hole exposing the drain electrode 213. [

An organic electroluminescent diode E is formed in a region substantially displaying an image on the driving thin film transistor DTr. The organic electroluminescent diode E includes a first electrode 111, an organic emission layer 113, Two electrodes 115 are formed.

The first electrode 111 is connected to the drain electrode 213 of the driving thin film transistor DTr and the light emitted from the organic light emitting layer 113 is driven by the lower light emitting method in which the light is emitted toward the first electrode 111. [

Banks 221 are located between the first electrodes 111 formed in the respective pixel regions P so that the first electrodes 111 are formed in the pixel regions P.

The second substrate 102 is provided on the driving TFT DTr and the organic light emitting diode E so that the first and second substrates 101 and 102 are electrically connected to each other through the protective layer 300 having adhesiveness. And they are separated from each other and joined together.

Thereby, the OLED 100 is encapsulated.

At this time, the protective layer 300 may include barium oxide (BaO) or calcium oxide (CaO) having a hydrophobic property or a moisture absorption characteristic therein, thereby preventing water from penetrating into the OLED 100 from the outside .

In addition, it is possible to omit a conventional seal pattern (20 in Fig. 1), to prevent defects caused by an actual pattern (20 in Fig. 1) It is possible to prevent cracks of the first and second electrodes 111 and 115 or the driving thin film transistor DTr from being generated.

In particular, the protective layer 300 according to the second embodiment of the present invention includes a material having a high thermal conductivity.

That is, the protective layer 300 includes graphite particles 310 having high thermal conductivity, through which the protective layer 300 has thermal conductivity.

Therefore, the high temperature heat generated together with the deterioration of the driving thin film transistor DTr and the organic light emitting diode E when the OLED 100 is driven is conducted to the protective layer 300 through the graphite particles 310, The heat of the high temperature transferred to the protective layer 300 is effectively diffused into the entire protective layer 300.

Accordingly, it is possible to effectively dissipate the heat generated from the inside of the OLED 100 to the outside, thereby preventing the lifetime of the OLED 100 from being drastically reduced.

At this time, in addition to the graphite particles 310, a metal oxide such as silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), zinc oxide (ZnO) Cu), nickel (Ni), and silver (Ag) may be used.

In particular, the OLED 100 of the present invention can realize light weight and thin shape at the same time as effectively dissipating heat at a high temperature.

That is, by eliminating the heat sink (30 in FIG. 1) such as a fan (not shown) or a heat pipe (not shown) for dissipating heat of the OLED 100, lightness and thinness can be realized.

Also, the problem that the organic electroluminescent diode E is damaged (C, D in FIG. 2) is prevented through the lamination process proceeding to attach the heat sink (30 in FIG. 1) to the OLED 100.

Meanwhile, the second substrate 102 may be formed of a metal foil to further improve the heat radiation characteristics of the OLED 100.

The present invention is not limited to the above-described embodiments, and various modifications may be made without departing from the spirit of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 schematically shows a cross-section of a general active matrix type OLED;

2 is a photograph showing an organic electroluminescent diode damaged.

3 is a cross-sectional view schematically showing an OLED according to a first embodiment of the present invention.

Fig. 4 is an enlarged cross-sectional view of a portion of Fig. 3; Fig.

5 is a view schematically showing the size of the heat radiation film.

6 is a cross-sectional view schematically illustrating an OLED according to a second embodiment of the present invention.

7 is an enlarged cross-sectional view of part of FIG. 6;

Claims (9)

A first substrate on which a driving thin film transistor and an organic light emitting diode are formed; A second substrate spaced apart from the first substrate by a protective layer; And A heat-radiating film attached to an inner surface of the second substrate and having a thickness of at least 1/2 of the protective layer, And an organic electroluminescent device. delete The method according to claim 1, The heat dissipation film is formed by coating graphite or metal particles such as aluminum (Al), copper (Cu), nickel (Ni) and silver (Ag) on a base film. delete The method according to claim 1, The size of the heat dissipation film is larger than that of the active region in which the image is implemented in a plan view, and is smaller than the size of the protective layer. The method according to claim 1, The heat radiating film may be formed of a non-metallic particle such as graphite particles, silicon oxide (SiO ₂ ), aluminum oxide (Al ₂ O ₃ ), titanium oxide (TiO ₂ ), zinc oxide (ZnO) Wherein the protective layer comprises at least one of metal particles such as nickel (Ni) and silver (Ag), and the protective layer has thermal conductivity through the heat radiation film. The method according to claim 1, Wherein the protective layer is disposed on the driving TFT and the organic light emitting diode. 8. The method of claim 7, Wherein the protective layer comprises barium oxide (BaO) or calcium oxide (CaO), which is hydrophobic or hygroscopic material. The method according to claim 1, Wherein the second substrate is a metal foil.

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