KR20080054569A - Organic light emitting device - Google Patents

Abstract

An organic light emitting display device is provided to efficiently radiate heat inside the device by forming a first metal film with low potential energy inside the device and a second metal film with high potential energy outside the device. A pixel electrode(191), an organic light emitting member(370), and a common electrode(270) are sequentially formed on an insulating substrate(110). A first metal film(71) is formed on the common electrode. A sealing member(60) covers the common electrode and the insulating substrate. A second metal film(72) is formed on the sealing member. The first metal film has lower potential energy than that of the second metal film. The first metal film is partially exposed outside the sealing member.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DEVICE}

1 is an equivalent circuit diagram of an organic light emitting diode display according to an exemplary embodiment of the present invention.

2 is a plan view of an organic light emitting diode display according to an exemplary embodiment of the present invention.

3 is a cross-sectional view of the organic light emitting diode display of FIG. 2 taken along the line III-III.

4 is a layout view of one pixel of an organic light emitting display panel of an organic light emitting diode display according to an exemplary embodiment.

5 and 6 are cross-sectional views of the organic light emitting diode display of FIG. 4 taken along the lines V-V and VI-VI, respectively.

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

60: sealing member 61: insulating film

71: first metal film 72: second metal film

81, 82: contact auxiliary member 85: connecting member

110: substrate 121, 129: gate line

124a: first control electrode 124b: second control electrode

127: sustain electrode 140: gate insulating film

154a: first island semiconductor 154b: second island semiconductor

163a and 165a: first resistive contact member

163b and 165b: second resistive contact member

171 and 179: data line 172: driving voltage line

173a: first input electrode 173b: second input electrode

175a: first output electrode 175b: second output electrode

175: drain electrode 180: protective film

181, 182, 184, 185a, 185b: contact hole

191: pixel electrode 270: common electrode

361: partition 365: opening

370: organic light emitting member

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

Recently, there is a demand for weight reduction and thinning of a monitor or a television, and according to such a demand, a cathode ray tube (CRT) has been replaced by a liquid crystal display (LCD). However, the liquid crystal display device requires not only a separate backlight as a light emitting device, but also has many problems in response speed and viewing angle. Recently, as a display device capable of overcoming such a problem, an organic light emitting device has attracted attention.

The organic light emitting diode display includes two electrodes and a light emitting layer interposed therebetween, and electrons injected from one electrode and holes injected from another electrode are combined in the light emitting layer to form an exciton. The excitons emit light while releasing energy. The organic light emitting diode display is not only advantageous in terms of power consumption because it does not need a separate light source, and also has excellent response speed, viewing angle, and contrast ratio.

However, since the organic light emitting diode display is a self-emission type, when it is driven for a long time, the organic light emitting member of the light emitting layer is deteriorated due to heat generated in the light emitting layer itself, resulting in denaturation and decomposition. The denatured and decomposed organic light emitting member causes variation in luminance between pixels, resulting in deterioration of image quality and lifespan such as afterimage. In particular, as the size of the organic light emitting diode display increases, the problem of heat generation becomes more pronounced.

An object of the present invention is to provide an organic light emitting display device capable of effectively emitting heat generated from the organic light emitting member to the outside.

An organic light emitting diode display according to an exemplary embodiment of the present invention includes a pixel electrode, an organic light emitting member and a common electrode, which are sequentially formed on an insulating substrate, a first metal layer formed on the common electrode, the common electrode, and the insulating substrate. And a second metal film formed on the encapsulating member, wherein the first metal film is a metal film having a lower potential energy than the second metal film.

In addition, a portion of the first metal film is exposed to the outside of the encapsulation member, and a portion of the first metal film and the second metal film are preferably connected by a flexible circuit film.

In addition, it is preferable that a current flows from the first metal film to the second metal film.

The first metal film is bismuth (Bi), the second metal film is antimony (Sb), the first metal film is bismuth (Bi), and the second metal film is tellurium (Te).

In addition, it is preferable that an insulating film is further formed between the common electrode and the first metal film.

Then, embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art can easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

In the drawings, the thickness of layers, films, panels, regions, etc., are exaggerated for clarity. Like parts are designated by like reference numerals throughout the specification. When a part of a layer, film, region, plate, etc. is said to be "on" another part, this includes not only the other part being "right over" but also another part in the middle. On the contrary, when a part is "just above" another part, there is no other part in the middle.

First, an organic light emitting diode display according to an exemplary embodiment of the present invention will be described in detail with reference to FIG. 1.

1 is an equivalent circuit diagram of an organic light emitting diode display according to an exemplary embodiment of the present invention.

Referring to FIG. 1, the organic light emitting diode display according to the present exemplary embodiment includes a plurality of signal lines 121, 171, and 172 and a plurality of pixels PX connected to the plurality of signal lines 121, 171, and 172 and arranged in a substantially matrix form. ).

The signal line includes a plurality of gate lines 121 for transmitting a gate signal (or scan signal), a plurality of data lines 171 for transmitting a data signal, and a plurality of driving voltage lines for transmitting a driving voltage. and a driving voltage line 172. The gate lines 121 extend substantially in the row direction, and are substantially parallel to each other, and the data line 171 and the driving voltage line 172 extend substantially in the column direction, and are substantially parallel to each other.

Each pixel PX includes a switching transistor Qs, a driving transistor Qd, a storage capacitor Cst, and an organic light emitting diode LD. do.

The switching transistor Qs has a control terminal, an input terminal, and an output terminal. The control terminal is connected to the gate line 121, and the input terminal is a data line 171. ) And the output terminal is connected to the driving transistor Qd. The switching transistor Qs transfers the data signal applied to the data line 171 to the driving transistor Qd in response to the scan signal applied to the gate line 121.

The driving transistor Qd also has a control terminal, an input terminal and an output terminal, the control terminal being connected to the switching transistor Qs, the input terminal being connected to the driving voltage line 172, and the output terminal being the organic light emitting diode. It is connected to (LD). The driving transistor Qd flows an output current ILD whose magnitude varies depending on the voltage applied between the control terminal and the output terminal.

The capacitor Cst is connected between the control terminal and the input terminal of the driving transistor Qd. The capacitor Cst charges the data signal applied to the control terminal of the driving transistor Qd and maintains it even after the switching transistor Qs is turned off.

The organic light emitting diode LD has an anode connected to the output terminal of the driving transistor Qd and a cathode connected to the common voltage Vss. The organic light emitting diode LD displays an image by emitting light having a different intensity depending on the output current ILD of the driving transistor Qd.

The switching transistor Qs and the driving transistor Qd are n-channel field effect transistors (FETs). However, at least one of the switching transistor Qs and the driving transistor Qd may be a p-channel field effect transistor. In addition, the connection relationship between the transistors Qs and Qd, the capacitor Cst, and the organic light emitting diode LD may be changed.

Next, the detailed structure of the organic light emitting diode display illustrated in FIG. 1 will be described in detail with reference to FIGS. 2 to 6.

2 is a plan view of an organic light emitting diode display according to an exemplary embodiment of the present invention, FIG. 3 is a cross-sectional view of the organic light emitting diode display of FIG. 2 taken along a line III-III, and FIG. 4 is an embodiment of the present invention. 5 and 6 are cross-sectional views of the organic light emitting diode display of FIG. 4 taken along a VV line and a VI-VI line, respectively.

As shown in FIGS. 2 and 3, the organic light emitting diode display includes a pixel electrode 191, an organic light emitting member 370, and a common electrode 270 that are sequentially formed on the insulating substrate 110 to display an image. A bar member 60 covering the electrode 270 and the insulating substrate 110 is included.

The first metal film 71 is positioned between the common electrode 270 and the encapsulation member 60, and the second metal film 72 is positioned on the encapsulation member 60. The pad portion 71a of the first metal layer 71 is exposed to the outside of the encapsulation member 60, and the pad portion 71a of the first metal layer 71 and the second metal layer 72 are of the flexible circuit film. It is connected by 80. The flexible circuit film 80 is an insulating film such as polyimide in which a wiring pattern is formed. Then, a current flows from the first metal film 71 to the second metal film 72. In the first metal film 71, a current flows in the A direction, and in the second metal film 72, B flows. Current is flowing in the direction. The first metal film 71 is preferably a metal film having a lower potential energy than the second metal film 72. For example, the first metal film 71 is formed of bismuth Bi and the second metal film 72 is formed of antimony Sb, or the first metal film 71 is formed of bismuth Bi. The second metal film 72 may be formed of tellurium (Te).

In order to move electrons from the first metal film 71 having a low potential energy to the second metal film 72 having a high potential energy, energy such as heat must be absorbed from the outside, and conversely, a second metal film having a high potential energy ( When electrons move to the first metal film 71 having a low potential energy in 72, energy is emitted. This phenomenon is called the peltier effect, and when the direct current flows through a circuit composed of different kinds of conductors, one side is heated at the junction between the different conductors according to the direction of the current. The other is the cooling phenomenon.

Therefore, since the first metal film 71 is cooled and the second metal film 72 is heated, the first metal film 71 positioned inside the organic light emitting display device sealed by the encapsulation member 60 absorbs heat. The second metal film 72 located outside the encapsulation member 60 generates heat. At this time, the first metal film 71 and the second metal film 72 are positioned with the encapsulation member 60 therebetween in order to separate the endothermic and exothermic phenomena occurring at the same time. Accordingly, heat generated in the organic light emitting diode display is absorbed by the first metal layer 71 and is emitted to the outside of the organic light emitting diode display through the second metal layer 72 positioned outside the encapsulation member 60.

As such, the first metal film 71 having low potential energy is positioned inside the sealing member 60 of the organic light emitting diode display, and the second metal film having high potential energy outside the organic light emitting diode display ( 72) and the Peltier effect can be used to efficiently discharge heat generated inside the organic light emitting diode display to the outside.

Therefore, deterioration of the organic light emitting member caused by the accumulation of heat inside the organic light emitting display device and the increase in temperature can be prevented, so that uniformity decrease or afterimage phenomenon due to the difference in luminance between pixels can be prevented, and degeneration of the organic light emitting member can be prevented. Alternatively, the degradation of lifespan caused by decomposition can be alleviated.

A detailed structure of the organic light emitting diode display will be described with reference to FIGS. 4 to 6.

4 to 6, a plurality of gate lines 121 and a plurality of second lines including a first control electrode 124a on an insulating substrate 110 made of transparent glass or plastic. A plurality of gate conductors including the control electrode 124b is formed.

The gate line 121 transmits a gate signal and mainly extends in a horizontal direction. Each gate line 121 includes a wide end portion 129 for connection with another layer or an external driving circuit, and the first control electrode 124a extends upward from the gate line 121. When a gate driving circuit (not shown) generating a gate signal is integrated on the substrate 110, the gate line 121 may extend to be directly connected to the gate driving circuit.

The second control electrode 124b is separated from the gate line 121 and includes a storage electrode 127 extending downward and briefly changing to the right and extending upward.

The gate conductors 121 and 124b are made of aluminum-based metals such as aluminum (Al) and aluminum alloys, silver-based metals such as silver (Ag) and silver alloys, copper-based metals such as copper (Cu) and copper alloys, and molybdenum (Mo) It may be made of molybdenum-based metals such as molybdenum alloys, chromium (Cr), tantalum (Ta), and titanium (Ti). However, they may have a multilayer structure including two conductive films (not shown) having different physical properties. One of the conductive films is made of a metal having low resistivity, such as aluminum-based metal, silver-based metal, or copper-based metal, so as to reduce signal delay or voltage drop. On the other hand, other conductive films are made of other materials, particularly materials having excellent physical, chemical and electrical contact properties with indium tin oxide (ITO) and indium zinc oxide (IZO), such as molybdenum-based metals, chromium, titanium, tantalum, and the like. Good examples of such a combination include a chromium bottom film, an aluminum (alloy) top film, and an aluminum (alloy) bottom film and a molybdenum (alloy) top film. However, the gate conductors 121 and 124b may be made of various metals or conductors.

Side surfaces of the gate conductors 121 and 124b are inclined with respect to the substrate 110 surface, and the inclination angle thereof is preferably about 30 mm to about 80 mm.

A gate insulating layer 140 made of silicon nitride (SiNx) or silicon oxide (SiOx) is formed on the gate conductors 121 and 124b.

On the gate insulating layer 140, a plurality of first and second island-like semiconductors 154a and 154b made of hydrogenated amorphous silicon (amorphous silicon is abbreviated a-Si), polycrystalline silicon, or the like are formed. It is. The first and second semiconductors 154a and 154b are positioned on the first and second control electrodes 124a and 124b, respectively.

A plurality of pairs of first ohmic contacts 163a and 165a and a plurality of pairs of second ohmic contacts 163b and 165b are formed on the first and second semiconductors 154a and 154b, respectively. The ohmic contacts 163a, 163b, 165a, and 165b have an island shape, and may be made of a material such as n + hydrogenated amorphous silicon in which n-type impurities such as phosphorus are heavily doped or made of silicide. The first ohmic contacts 163a and 165a are arranged in pairs on the first semiconductor 154a, and the second ohmic contacts 163b and 165b are also arranged in pairs and disposed on the second semiconductor 154b.

The plurality of data lines 171, the plurality of driving voltage lines 172, and the plurality of first and second output electrodes 175a are disposed on the ohmic contacts 163a, 163b, 165a, and 165b and the gate insulating layer 140. , A plurality of data conductors including 175b are formed.

The data line 171 transmits a data signal and mainly extends in the vertical direction to cross the gate line 121. Each data line 171 has a wide end portion 179 for connection of a plurality of first input electrodes 173a extending toward the first control electrode 124a with another layer or an external driving circuit. It includes. When a data driving circuit (not shown) generating a data signal is integrated on the substrate 110, the data line 171 may be extended to be directly connected to the data driving circuit.

The driving voltage line 172 transfers a driving voltage and mainly extends in the vertical direction to cross the gate line 121. Each driving voltage line 172 includes a plurality of second input electrodes 173b extending toward the second control electrode 124b. The driving voltage line 172 overlaps the storage electrode 127 and may be connected to each other.

The first and second output electrodes 175a and 175b are separated from each other and also separated from the data line 171 and the driving voltage line 172. The first input electrode 173a and the first output electrode 175a face each other with respect to the first control electrode 124a, and the second input electrode 173b and the second output electrode 175b are the second control electrode. Facing each other around 124b.

The data conductors 171, 172, 175a, and 175b are preferably made of a refractory metal such as molybdenum, chromium, tantalum, and titanium, or an alloy thereof, and include a refractory metal film (not shown) and a low resistance conductive film (not shown). It may have a multi-layer structure including). Examples of the multilayer structure include a double layer of chromium or molybdenum (alloy) lower layer and an aluminum (alloy) upper layer, and a triple layer of molybdenum (alloy) lower layer and aluminum (alloy) interlayer and molybdenum (alloy) upper layer. However, the data conductors 171, 172, 175a, and 175b may be made of various other metals or conductors.

Like the gate conductors 121 and 124b, the data conductors 171, 172, 175a and 175b also preferably have their side surfaces inclined at an inclination angle of about 30 to 80 degrees with respect to the surface of the substrate 110.

The ohmic contacts 163a, 163b, 165a, and 165b exist only between the semiconductors 154a and 154b below and the data conductors 171, 172, 175a, and 175b thereon, thereby lowering the contact resistance. The semiconductors 154a and 154b have portions exposed between the input electrodes 173a and 173b and the output electrodes 175a and 175b as well as the data conductors 171, 172, 175a and 175b.

A passivation layer 180 is formed on the data conductors 171, 172, 175a, and 175b and the exposed portions of the semiconductors 154a and 154b. The passivation layer 180 is made of an inorganic insulator such as silicon nitride (SiNx) or silicon oxide (SiOx), an organic insulator, or a low dielectric insulator. The dielectric constant of the organic insulator and the low dielectric insulator is preferably 4.0 or less, for example, a-Si: C: O, a-Si: O: F, etc. formed by plasma enhanced chemical vapor deposition (PECVD). to be. The passivation layer 180 may be formed by having photosensitivity among the organic insulators, and the surface of the passivation layer 180 may be flat. However, the passivation layer 180 may have a double layer structure of the lower inorganic layer and the upper organic layer so as not to damage the exposed portions of the semiconductors 154a and 154b while maintaining excellent insulating properties of the organic layer.

The passivation layer 180 has a plurality of contact holes 182, 185a, and 185b exposing the end portion 179 of the data line 171 and the first and second output electrodes 175b, respectively. In the passivation layer 180, the blocking layer 186, and the gate insulating layer 140, a plurality of contact holes 181 and 184 exposing the end portion 129 of the gate line 121 and the second input electrode 124b are formed. It is.

A plurality of pixel electrodes 191, a plurality of connecting members 85, and a plurality of contact assistants 81 and 82 are formed on the passivation layer 180. These may be made of a transparent conductive material such as ITO or IZO or a reflective metal such as aluminum, silver or an alloy thereof.

The pixel electrode 191 is physically and electrically connected to the second output electrode 175b through the contact hole 185b, and the connection member 85 is connected to the second control electrode 124b through the contact holes 184 and 185a. ) And the first output electrode 175a.

The contact auxiliary members 81 and 82 are connected to the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 through the contact holes 181 and 182, respectively. The contact auxiliary members 81 and 82 compensate for and protect the adhesion between the end portion 129 of the gate line 121 and the end portion 179 of the data line 171 and the external device.

A partition 361 is formed on the passivation layer 180. The partition 361 surrounds the edge of the pixel electrode 191 like a bank to define an opening 365 and is made of an organic insulator or an inorganic insulator. The partition 361 may also be made of a photosensitizer including a black pigment, in which case the partition 361 serves as a light blocking member and the forming process is simple.

An organic light emitting member 370 is formed in the opening 365 on the pixel electrode 191 defined by the partition 361. The organic light emitting member 370 is made of an organic material that uniquely emits light of any one of primary colors such as three primary colors of red, green, and blue. The organic light emitting diode display displays a desired image by using a spatial sum of the primary color light emitted by the organic light emitting members 370.

The organic light emitting member 370 may have a multilayer structure including an auxiliary layer (not shown) for improving the light emitting efficiency of the light emitting layer in addition to the light emitting layer (not shown) for emitting light. The secondary layer includes an electron transport layer (not shown) and a hole transport layer (not shown) to balance electrons and holes, and an electron injection layer to enhance injection of electrons and holes. electron injecting layer (not shown) and hole injecting layer (not shown).

The common electrode 270 is formed on the organic light emitting member 370. The common electrode 270 receives a common voltage Vss and is made of a reflective metal including calcium (Ca), barium (Ba), magnesium (Mg), aluminum, silver, or the like, or a transparent conductive material such as ITO or IZO. .

An insulating layer 61 is formed on the common electrode 270 to insulate, a first metal layer 71 is formed on the insulating layer 61, and an encapsulation layer covering the organic light emitting display device on the first metal layer 71. The member 60 is formed. The second metal film 72 is formed on the encapsulation member 60, and as shown in FIGS. 3 and 4, the second metal film 72 is connected to the first metal film 71. Current flows from the first metal film 71 to the second metal film 72. Since the second metal layer 72 has a higher potential energy than the first metal layer 71, an endothermic phenomenon occurs in the first metal layer 71, and an exothermic phenomenon occurs in the second metal layer 72, resulting in organic light emission. The heat generated by the display device can be effectively released to the outside.

In the organic light emitting diode display, the first control electrode 124a connected to the gate line 121, the first input electrode 173a and the first output electrode 175a connected to the data line 171 may be formed. 1 together with the semiconductor 154a, a switching TFT Qs is formed, and a channel of the switching TFT Qs is formed between the first input electrode 173a and the first output electrode 175a. 1 is formed in the semiconductor 154a. The second control electrode 124b connected to the first output electrode 175a, the second input electrode 173b connected to the driving voltage line 172, and the second output electrode connected to the pixel electrode 191 ( 175b forms a driving TFT Qd together with the second semiconductor 154b, and a channel of the driving TFT Qd is formed between the second input electrode 173b and the second output electrode 175b. It is formed in the second semiconductor 154b. The pixel electrode 191, the organic light emitting member 370, and the common electrode 270 form an organic light emitting diode LD, and the pixel electrode 191 is an anode and the common electrode 270 is a cathode. Alternatively, the pixel electrode 191 becomes a cathode and the common electrode 270 becomes an anode. The storage electrode 127 and the driving voltage line 172 overlapping each other form a storage capacitor Cst.

The organic light emitting diode display emits light toward the top or the bottom of the substrate 110 to display an image. The opaque pixel electrode 191 and the transparent common electrode 270 are applied to a top emission type organic light emitting display device that displays an image in an upward direction of the substrate 110. The opaque common electrode 270 is applied to a bottom emission organic light emitting display device that displays an image in a downward direction of the substrate 110.

On the other hand, when the semiconductors 154a and 154b are polycrystalline silicon, an intrinsic region (not shown) facing the control electrodes 124a and 124b and an impurity region (extrinsic region) located at both sides thereof are not shown. Not included). The impurity region is electrically connected to the input electrodes 173a and 173b and the output electrodes 175a and 175b, and the ohmic contacts 163a, 163b, 165a and 165b may be omitted.

In addition, the control electrodes 124a and 124b may be disposed on the semiconductors 154a and 154b, and the gate insulating layer 140 may be positioned between the semiconductors 154a and 154b and the control electrodes 124a and 124b. In this case, the data conductors 171, 172, 173b, and 175b may be disposed on the gate insulating layer 140 and may be electrically connected to the semiconductors 154a and 154b through contact holes (not shown) bored in the gate insulating layer 140. . Alternatively, the data conductors 171, 172, 173b, and 175b may be positioned under the semiconductors 154a and 154b to be in electrical contact with the semiconductors 154a and 154b thereon.

In the organic light emitting diode display according to the present invention, a first metal layer 71 having a low potential energy is positioned inside the organic light emitting diode display, which is sealed by the encapsulation member 60, and the potential energy is outside the organic light emitting diode display. The high second metal layer 72 may be positioned to efficiently discharge heat generated inside the organic light emitting diode display to the outside. Therefore, deterioration of the organic light emitting member caused by the accumulation of heat inside the organic light emitting display device and the increase in temperature can be prevented, so that uniformity decrease or afterimage phenomenon due to the difference in luminance between pixels can be prevented, and degeneration of the organic light emitting member can be prevented. Alternatively, the degradation of lifespan caused by decomposition can be alleviated.

Although a preferred embodiment of the present invention has been described in detail above, those skilled in the art will understand that various modifications and equivalent other embodiments are possible therefrom. Accordingly, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concept of the present invention as defined in the following claims also fall within the scope of the present invention.

Claims (7)

A pixel electrode, an organic light emitting member and a common electrode which are sequentially formed on an insulating substrate, A first metal film formed on the common electrode, A bar member covering the common electrode and the insulating substrate, and A second metal film formed on the sealing member Including, And the first metal layer is a metal layer having a lower potential energy than the second metal layer. In claim 1, A portion of the first metal layer is exposed to the outside of the encapsulation member. In claim 2, A portion of the first metal film and the second metal film are connected by a flexible circuit film. In claim 3, An organic light emitting display device in which a current flows from the first metal film to the second metal film. In claim 1, The first metal layer is bismuth (Bi), and the second metal layer is antimony (Sb). In claim 1, The first metal layer is bismuth (Bi), and the second metal layer is tellurium (Te). In claim 1, And an insulating film further formed between the common electrode and the first metal film.

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