KR20160069045A - Brightness enhancing layer and organic Light Emitting Diode Display Device including the same - Google Patents

Abstract

The present invention provides a brightness enhancing layer including an organic binder and an opened carbon nanotube. The brightness enhancing layer is used as an insulating layer. For example, the brightness enhancing layer can increase the brightness of an organic light emitting diode display device.

Description

[0001] The present invention relates to a brightness enhancement layer and an organic light emitting diode display device including the same,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting diode (OLED) display, and more particularly, to a brightness enhancement layer capable of increasing light transmission from an organic emission layer and an organic light emitting diode display having improved brightness including the same.

An organic light emitting diode (OLED) display device, which is one of a flat panel display (FPD), has high luminance and low operating voltage characteristics.

In addition, since it is a self-luminous type that emits light by itself, it has a large contrast ratio, can realize an ultra-thin display, can realize a moving image with a response time of several microseconds (μs), has no viewing angle limit, And it is driven with a low voltage of 5 to 15 V direct current, so that it is easy to manufacture and design a driving circuit.

In addition, since the manufacturing process of the organic light emitting diode display device is all of deposition and encapsulation, the manufacturing process is very simple.

Such an organic light emitting diode display device includes a plurality of pixel regions, and a switching thin film transistor and a driving thin film transistor are formed in a plurality of pixel regions.

Generally, a thin film transistor is manufactured using a semiconductor material such as amorphous silicon.

Recently, a large-area and high-resolution display device is required, and a need for a thin film transistor having stable operation and durability with a faster signal processing speed is required. However, the amorphous silicon thin film transistor has a charge mobility of 1 cm ² / Vsec or less, a surface which is insufficient to be used for a large-area and high-resolution display device is highlighted.

Accordingly, studies have been actively made on an oxide thin film transistor which forms an active layer with an oxide semiconductor material excellent in electrical characteristics such as mobility and off current.

1 is a cross-sectional view schematically showing a conventional OLED display.

1, a conventional organic light emitting diode display device 10 includes a first substrate 10, a second substrate (not shown) facing the first substrate 10, a first substrate 10 And a driving thin film transistor (Td) and a light emitting diode (D) sequentially formed on the upper substrate (10).

The first substrate 10 and the second substrate (not shown) which are spaced apart from each other include a plurality of pixel regions (not shown). The first substrate 10 is referred to as a lower substrate, a TFT substrate, or a backplane And the second substrate (not shown) may also be referred to as an encapsulation substrate.

The driving thin film transistor Td includes a semiconductor layer 12, a gate electrode 30, a source electrode 52 and a drain electrode 54. [

Specifically, the semiconductor layer 12 is located on the first substrate 10. For example, the semiconductor layer 12 may be made of an oxide semiconductor material.

A gate insulating film 22 is formed on the entire surface of the first substrate 10 so as to cover the semiconductor layer 12. The gate insulating film 22 is made of an inorganic insulating material such as silicon oxide or silicon nitride.

The gate electrode 30 is located on the gate insulating film 22 and overlaps with the semiconductor layer 12. [

An interlayer insulating film 40 having first and second semiconductor layer contact holes 42 and 44 exposing both sides of the semiconductor layer 12 is formed covering the gate electrode 30. The interlayer insulating film 40 is made of an organic insulating material such as photoacryl.

The source electrode 52 and the drain electrode 54 are formed on the interlayer insulating film 40 and are in contact with both sides of the semiconductor layer 12 through the first and second semiconductor layer contact holes 42 and 44,

A planarizing film 60 having a drain contact hole 62 for providing a flat surface and exposing the drain electrode 54 is formed covering the driving thin film transistor Td. The planarizing film 60 is formed of an organic insulating material.

The light emitting diode D is located on the planarization layer 60 and is electrically connected to the driving thin film transistor Td through the drain contact hole 62. The light emitting diode D includes a first electrode 70 sequentially stacked, and an organic light emitting layer 74 and a second electrode 76.

The first electrode 70 is formed on the planarization layer 60 and is connected to the drain electrode 54 of the driving TFT Td through the drain contact hole 62. The first electrode 70 is formed for each pixel region. On the first electrode 70, a bank 72 covering the edge is formed. The bank 72 is formed along the boundary of the pixel region and has an opening corresponding to the central portion of the first electrode 70.

The organic light emitting layer 74 is in contact with the first electrode 70 and is formed in the opening of the bank 72. The second electrode 76 is in contact with the upper surface of the organic light emitting layer 74, Respectively.

The first electrode 70 is made of a conductive material having a relatively large work function value, and the second electrode 76 is made of a conductive material having a relatively low work function. For example, the first electrode 70 is made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO) The two electrodes 76 are made of aluminum (Al), magnesium (Mg), and an aluminum-magnesium alloy (AlMg).

In the light emitting diode D, holes injected from the first electrode 70 and electrons injected from the second electrode 76 are combined in the organic light emitting layer 74 to form an exciton, Light is emitted from the organic light emitting layer 74 while being transited to the ground state.

For example, when the organic light emitting diode display device is a bottom emission type, light from the organic light emitting layer 74 passes through the first electrode 70, the planarization layer 60, the interlayer insulation layer 40, And the first substrate 10 to display an image.

However, in the conventional organic light emitting diode display device, only a part of the light emitted from the organic light emitting layer 74 passes through the first substrate 10, so that the organic light emitting diode display device has a low luminance. In order to increase the luminance of the organic light emitting diode, there arises a problem that the driving voltage increases.

The present invention aims at minimizing the loss of light emitted from the organic light emitting layer.

That is, the organic light emitting diode display device is intended to solve the problem of reduction in luminance and increase in driving voltage.

In order to solve the above problems, the present invention provides an organic binder and a brightness enhancement layer including open carbon nanotubes.

In the brightness enhancement layer of the present invention, the open carbon nanotubes are arranged in the same direction.

According to another aspect of the present invention, there is provided a thin film transistor comprising: a substrate; a thin film transistor disposed on the substrate; a light emitting diode disposed on the thin film transistor and connected to the thin film transistor; And an organic light emitting diode display device including a first brightness enhancement layer including open carbon nanotubes.

In the organic light emitting diode display of the present invention, the first open carbon nanotube is arranged perpendicular to the substrate.

In the organic light emitting diode display of the present invention, the first brightness enhancement layer includes a contact hole exposing an electrode of the thin film transistor, and the light emitting diode is connected to the thin film transistor through the contact hole.

In the organic light emitting diode display of the present invention, the light emitting diode may include a first electrode connected to the thin film transistor, an organic light emitting layer on the first electrode, and a second electrode on the organic light emitting layer, Light from the organic light emitting layer passes through the first brightness enhancement layer and the substrate, and an image is displayed.

In the organic light emitting diode display device of the present invention, the thin film transistor includes a semiconductor layer, a gate insulating film on the semiconductor layer, a gate electrode on the gate insulating film, a second brightness enhancement layer covering the gate electrode, And a source electrode and a drain electrode spaced apart from each other on the second brightness enhancement layer and in contact with the semiconductor layer, respectively, and the second brightness enhancement layer includes a second open carbon nanotube.

In the organic light emitting diode display of the present invention, the second open carbon nanotube is arranged perpendicular to the substrate.

According to another aspect of the present invention, there is provided a thin film transistor comprising: a substrate; a thin film transistor disposed on the substrate; a light emitting diode disposed on the thin film transistor and connected to the thin film transistor; And an organic electroluminescent display device including the brightness enhancement layer.

In the organic light emitting diode display of the present invention, the open carbon nanotubes are arranged perpendicular to the substrate.

In the organic light emitting diode display of the present invention, the light emitting diode may include a first electrode connected to the thin film transistor, an organic light emitting layer on the first electrode, and a second electrode on the organic light emitting layer, Light from the organic light emitting layer passes through the second electrode and the brightness enhancement layer to display an image.

In the organic light emitting diode display of the present invention, the first electrode includes a transparent conductive electrode layer and a reflective layer.

The present invention provides a brightness enhancement layer including an open carbon nanocarbon tube inside an insulating film to increase light transmittance.

Therefore, when the brightness enhancement layer including the open carbon nano-carbon tube is formed on the upper or lower portion of the light emitting diode, the amount of light emitted from the organic light emitting layer of the light emitting diode can be increased to the image display surface. That is, the luminance of the organic light emitting diode display device is increased and the driving voltage is reduced.

Further, since the brightness enhancing layer including the opened carbon nano-carbon tube has the insulating property, it can be used as the insulating layer of the array substrate. Therefore, the brightness of the organic light emitting diode display can be increased without adding a configuration or adding a process.

1 is a cross-sectional view schematically showing a conventional OLED display.
2 is a schematic circuit diagram of an organic light emitting diode display device according to an embodiment of the present invention.
3 is a schematic cross-sectional view of an organic light emitting diode display device according to a first embodiment of the present invention.
4 is a cross-sectional view illustrating a structure of a driving thin film transistor and a luminance enhancement layer of an organic light emitting diode display according to a first embodiment of the present invention.
5 is a schematic view showing carbon nanotubes (CNTs) vertically aligned on a Si substrate.
6 is a schematic perspective view showing a light path in the brightness enhancement layer.
7 is a schematic cross-sectional view of an organic light emitting diode display device according to a second embodiment of the present invention.
8 is a schematic cross-sectional view of an organic light emitting diode display device according to a third embodiment of the present invention.

Hereinafter, an organic light emitting diode display device and a method of manufacturing the same according to the present invention will be described with reference to the accompanying drawings.

As described above, in the conventional organic light emitting diode display device, the planarization layer 60 made of an organic insulating material, for example, a phto-acryl material, is formed between the light emitting diode D and the driving thin film transistor Td, Respectively.

In the organic light emitting diode display device having such a structure, the light emitted from the organic light emitting layer 74 passes through the planarization layer 60 and is displayed through the back surface of the substrate 10. When the light from the organic light emitting layer 74 is planarized Total reflection or diffuse reflection occurs on the surface of the film 60 or through it. Accordingly, the amount of light passing through the substrate 10 among the light from the organic light emitting layer 74 is reduced, thereby reducing the brightness of the organic light emitting diode display device.

In the present invention, an organic light emitting diode display device capable of solving the problem of luminance reduction due to a layer stacked on an organic light emitting diode display device such as the planarization layer 60 will be described.

2 is a schematic circuit diagram of an organic light emitting diode display device according to an embodiment of the present invention.

2, the organic light emitting diode display device according to the first embodiment of the present invention includes a gate line GL and a data line DL that define a pixel region P intersecting with each other, A switching thin film transistor Ts, a driving thin film transistor Td, a storage capacitor Cst, and a light emitting diode D are formed in the pixel region P of the organic EL element.

More specifically, the gate electrode of the switching thin film transistor Ts is connected to the gate wiring GL and the source electrode thereof is connected to the data wiring DL. The gate electrode of the driving thin film transistor Td is connected to the drain electrode of the switching thin film transistor Ts, and the source electrode thereof is connected to the high potential voltage VDD. The anode of the light emitting diode D is connected to the drain electrode of the driving thin film transistor Td and the cathode of the light emitting diode D is connected to the low potential voltage VSS. The storage capacitor Cst is connected to the gate electrode and the drain electrode of the driving thin film transistor Td.

The switching TFTs turn on according to the gate signal applied through the gate line GL and the data line DL is turned on at this time. Is applied to the gate electrode of the driving thin film transistor Td and one electrode of the storage capacitor Cst through the switching thin film transistor Ts.

The driving thin film transistor Td is turned on according to the data signal to control the current flowing through the light emitting diode D to display an image. The light emitting diode D emits light by a current of a high potential voltage (VDD) transmitted through the driving thin film transistor Td.

That is, since the amount of current flowing through the light emitting diode D is proportional to the size of the data signal and the intensity of light emitted by the light emitting diode D is proportional to the amount of current flowing through the light emitting diode D, ) Displays different gradations according to the size of the data signal, and as a result, the organic light emitting diode display displays an image.

The storage capacitor Cst maintains the charge corresponding to the data signal for one frame to keep the amount of current flowing through the light emitting diode D constant and to maintain the gradation displayed by the light emitting diode D constant .

- First Embodiment -

3 is a schematic cross-sectional view of an organic light emitting diode display device according to a first embodiment of the present invention. The brightness enhancement layer of the present invention will be described together with an organic light emitting diode display device.

3, the organic light emitting diode display 100 according to the first embodiment of the present invention includes a driving thin film transistor Td, a brightness enhancement layer 160 covering the driving thin film transistor Td, And a light emitting diode D which is positioned on the brightness enhancement layer 160 and connected to the driving thin film transistor Td.

4, which is a cross-sectional view illustrating a structure of a driving thin film transistor and a luminance improving layer of an organic light emitting diode display according to a first embodiment of the present invention, a driving thin film transistor Td includes a semiconductor layer 112, A gate electrode 130, a source electrode 152, and a drain electrode 154.

Specifically, a semiconductor layer 112 is formed on a substrate 110 made of glass or plastic. For example, the semiconductor layer 112 may be made of an oxide semiconductor material. In this case, a light shielding pattern (not shown) and a buffer layer (not shown) may be formed under the semiconductor layer 112. The light shielding pattern prevents light from entering the semiconductor layer 112, To be deteriorated by the light. Alternatively, the semiconductor layer 112 may be formed of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 112.

A gate insulating layer 122 made of an insulating material is formed on the entire surface of the substrate 110 on the semiconductor layer 112. The gate insulating film 122 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

A gate electrode 130 made of a conductive material such as metal is formed on the gate insulating layer 122 to correspond to the center of the semiconductor layer 112. A gate line (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 122. The gate wiring may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode 130. [

In the first embodiment of the present invention, the gate insulating layer 122 is formed on the entire surface of the substrate 110, but the gate insulating layer 122 may be patterned to have the same shape as the gate electrode 130.

An interlayer insulating layer 140 made of an insulating material is formed on the entire surface of the substrate 110 on the gate electrode 130. The interlayer insulating film 140 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride, or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating film 140 has first and second contact holes 142 and 144 exposing upper surfaces on both sides of the semiconductor layer 112. The first and second contact holes 142 and 144 are spaced apart from the gate electrode 130 on both sides of the gate electrode 130. Here, the first and second contact holes 142 and 144 are also formed in the gate insulating film 122. Alternatively, when the gate insulating film 122 is patterned in the same shape as the gate electrode 130, the first and second contact holes 142 and 144 are formed only in the interlayer insulating film 140.

A source electrode 152 and a drain electrode 154 are formed of a conductive material such as metal on the interlayer insulating layer 140. A data line (not shown), a power supply line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 140 in the second direction.

The source electrode 152 and the drain electrode 154 are spaced about the gate electrode 130 and contact both sides of the semiconductor layer 112 through the first and second contact holes 142 and 144, respectively . Although not shown, the data wiring extends along the second direction and intersects with the gate wiring to define the pixel region P, and the power supply wiring for supplying the high potential voltage is located apart from the data wiring. The second capacitor electrode is connected to the drain electrode 154 and overlaps the first capacitor electrode to form a storage capacitor by using the interlayer insulating film 140 between the first and second capacitor electrodes as a dielectric layer.

The semiconductor layer 112 and the gate electrode 130, the source electrode 152 and the drain electrode 154 constitute a driving thin film transistor Td. The driving thin film transistor Td includes a semiconductor layer 112, And has a coplanar structure in which the gate electrode 130, the source electrode 152, and the drain electrode 154 are located on the upper portion.

Alternatively, the driving thin film transistor Td may have an inverted staggered structure in which a gate electrode is located below the semiconductor layer and a source electrode and a drain electrode are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Further, a switching thin film transistor (Ts in Fig. 2) having substantially the same structure as the driving thin film transistor Td is further formed on the substrate 110. [ The gate electrode 130 of the driving thin film transistor Td is connected to the drain electrode of the switching thin film transistor Ts and the source electrode 152 of the driving thin film transistor Td is connected to the power supply wiring Lt; / RTI > A gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor Ts are connected to the gate wiring and the data wiring, respectively.

A luminance enhancement layer 160 including an opened carbon nano-tube 162 is formed on the entire surface of the substrate 110 on the source electrode 152 and the drain electrode 154. The brightness enhancement layer 160 has a flat upper surface and a drain contact hole 164 that exposes the drain electrode 154 of the driving thin film transistor Td. Here, the drain contact hole 164 is formed directly on the second contact hole 144, but may be formed apart from the second contact hole 144.

The brightness enhancement layer 160 includes carbon nanotubes 162 that are off from an organic binder (not shown) and functions as an insulating layer as well as guiding light emitted from the light emitting diode D. The open carbon nanotubes 162 are shown in Figure 5, which is a schematic view showing vertically oriented carbon nanotubes on a Si substrate. 5 is a schematic view showing carbon nanotubes vertically aligned on a Si substrate.

The organic binder may be selected from the group consisting of an epoxy acrylate resin, a urethane acrylate resin, a polyester acrylate resin, a silicone acrylate resin, an aminoacrylate resin, an epoxy methacrylate resin, a urethane methacrylate resin, a polyester methacrylate resin, Acrylate resins and aminomethacrylate resins, polyester resins, polyoletine resins, polysiloxane resins, and silicone modified polyimide resins.

Further, the brightness enhancement layer 160 may further include a monomer, an additive which is a silane coupling agent, a solvent, and a photoinitiator.

The light emitting diode D includes a first electrode 170 positioned on the brightness enhancement layer 160 and connected to the drain electrode 154 of the driving thin film transistor Td and a second electrode 170 sequentially stacked on the first electrode 170 An organic light emitting layer 174 and a second electrode 176.

The first electrode 170 is made of a conductive material having a relatively large work function value and is formed separately for each pixel region (P in FIG. 2). For example, the first electrode 170 may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

The organic light emitting layer 174 may have a single layer structure of a light emitting material layer or may have a hole injection layer, a hole transporting layer, a light emitting material layer, an electron transporting layer, , And an electron injection layer.

The second electrode 176 is made of a material having a relatively large work function value and can be formed integrally with the entire display region including a plurality of pixel regions P. [ For example, the second electrode 176 may be formed of any one of aluminum (Al), magnesium (Mg), and aluminum-magnesium alloy (AlMg).

A bank 172 having an opening exposing the center of the first electrode 170 and covering the edge of the first electrode 170 may be further formed on the brightness enhancement layer 160.

The holes from the first electrode 170 and the electrons from the second electrode 176 are combined at the organic light emitting layer 174 to form excitons and the excitons drop from the excited state to the ground state, ), That is, the organic light emitting layer 174 emits light.

In the organic light emitting diode display 100 according to the first embodiment of the present invention, light from the organic light emitting layer 174 passes through the brightness enhancement layer 160 and the substrate 110 to display an image. That is, it is a bottom emission type organic light emitting diode display device. At this time, the light from the organic light emitting layer 174 is guided by the open carbon nanotubes 162 of the brightness enhancement layer 160, thereby increasing the brightness of the organic light emitting diode display device 100.

6, which is a schematic perspective view showing a light path in the brightness enhancing layer, light from the light emitting diode D is emitted from one end of the open carbon nanotube 162 of the brightness enhancement layer 160 And is guided in the direction of the substrate (110 in FIG. 3) through the other end of the opened carbon nanotubes 162, the straightness in the direction of the substrate 110 increases. Accordingly, the amount of total reflection or diffuse reflection of light from the light emitting diode D is reduced, and the amount of light directed toward the substrate 110 is increased, so that the brightness of the organic light emitting diode display 100 is increased.

In FIGS. 3 and 4, it is shown that all of the open carbon nanotubes 162 are arranged perpendicular to the substrate 110. That is, the opened carbon nanotubes 162 are arranged parallel to the traveling direction of light. In other words, the open carbon nanotubes 162 are arranged in the same direction. Alternatively, the open carbon nanotubes 162 may be arranged in disorder. Although some of the open carbon nanotubes 162 are disorderly arranged, some of the open carbon nanotubes 162 act as paths of light because they are arranged perpendicularly or obliquely to the substrate 110.

The opened carbon nanotubes (162) are empty and both ends are open. That is, the light enters the open end of the opened carbon nanotube 162, proceeds through the inner space, and exits to the open end of the opened carbon nanotube 162, so that the linearity of light increases. At this time, the open carbon nanotubes 162 have a single layer or a double layer shell to form an inner space.

The opened carbon nanotubes 162 can be obtained by growing a carbon nanotube having an inner space on a silicon substrate and etching the carbon nanotube end on the opposite side of the substrate.

That is, the carbon nanotube has an open end in contact with the substrate surface, while the opposite end is grown in a closed state. Accordingly, when the closed end of the carbon nanotube is removed, it is possible to obtain an open carbon nanotube 162 which is opened as in the present invention and can provide a light path. For example, the closed end of the carbon nanotube can be etched by plasma treatment to open it.

Since the brightness enhancement layer 160 is formed in place of the conventional planarization layer (60 in FIG. 1), no additional process is required. Thus, the brightness of the organic light emitting diode display 100 can be increased without additional steps or additional layers.

Table 1 shows the optical characteristics in the case of using the conventional planarizing film (Comparative Example) and the case of using the luminance enhancement layer (Experimental Example) in the organic light emitting diode display device of the first embodiment described above.

As shown in Table 1, it can be seen that the light efficiency of the organic light emitting diode display device including the brightness enhancement layer including the carbon nanotubes opened as in the present invention is greatly improved.

Meanwhile, a drain contact hole 164 for exposing the drain electrode 154 should be formed in the brightness enhancement layer 160, so that a photo-lithography process must be performed. At this time, the drain contact hole 164 should be formed to have a size corresponding to the pattern formed on the exposure mask.

Comparative Example

(Additive, 3 wt%), propylene glycol monomethyl ether acetate (1 wt%), silicone acrylate resin (binder, 15 wt%), pentaerythritol hexaacrylate Solvent, 70 wt%) and 1-hydroxycyclohexyl phenyl ketone (photoinitiator, 2 wt%) were coated and cured to form an insulating film, and an exposure mask having a transmissive portion of 6 μm * 9 μm A photolithography process was carried out.

Experimental Example

(Monomer, 15 wt%), 3-glycidoxytrimethoxysilane (additive, 3 wt.%), Silicone resin (binder, 15 wt.%), Open carbon nanotube (5 wt.%), Pentaerythritol hexaacrylate (2 wt%) and 1-hydroxycyclohexyl phenyl ketone (photoinitiator, 2 wt%) were coated and cured to form an insulating film, and 6 A photolithography process was carried out using an exposure mask having a transmissive portion of 탆 * 9 탆.

As shown in Table 2, in the comparative example, an exposure amount of about 160 mJ / cm 2 is required for forming a contact hole of a desired size, whereas in the experimental example, an exposure amount of about 40 mJ / cm 2 is required. Therefore, in the case of the brightness enhancement layer of the present invention, power consumption for the photolithography process is reduced.

As described above, the brightness enhancement layer of the present invention has an advantage that the power consumption for the photolithography process is reduced while increasing the light transmittance.

- Second Embodiment -

7 is a schematic cross-sectional view of an organic light emitting diode display device according to a second embodiment of the present invention.

7, the organic light emitting diode display 200 according to the second embodiment of the present invention includes a driving thin film transistor Td, a first brightness enhancement layer (not shown) as an inner layer of the driving thin film transistor Td, A second brightness enhancement layer 260 covering the driving thin film transistor Td and a light emitting diode D positioned on the second brightness enhancement layer 260 and connected to the driving thin film transistor Td, .

The driving thin film transistor Td includes a semiconductor layer 212, a gate electrode 230, a source electrode 252 and a drain electrode 254. [

A semiconductor layer 212 is formed on a substrate 210 made of glass or plastic. For example, the semiconductor layer 212 may be made of an oxide semiconductor material. In this case, a light shielding pattern (not shown) and a buffer layer (not shown) may be formed under the semiconductor layer 212. The light shielding pattern prevents light from entering the semiconductor layer 212, To be deteriorated by the light. Alternatively, the semiconductor layer 212 may be made of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 212.

A gate insulating layer 222 made of an insulating material is formed on the entire surface of the substrate 210 on the semiconductor layer 212. The gate insulating film 222 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

A gate electrode 230 made of a conductive material such as metal is formed on the gate insulating layer 222 in correspondence with the center of the semiconductor layer 212. A gate line (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating layer 222. The gate wiring may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode 230.

The gate insulating layer 222 is formed on the entire surface of the substrate 210. The gate insulating layer 222 may be patterned to have the same shape as the gate electrode 230. [

A first brightness enhancement layer 240 including a first open carbon nanotube 241 is formed on the entire surface of the substrate 110 on the gate electrode 230. The first brightness enhancement layer 240 includes an organic binder (not shown) and a first off-off carbon nanotube 241 and functions as an insulating layer as well as guiding light emitted from the light emitting diode D .

The first brightness enhancement layer 240 has first and second contact holes 242 and 244 exposing upper surfaces on both sides of the semiconductor layer 212. The first and second contact holes 242 and 244 are spaced apart from the gate electrode 230 on both sides of the gate electrode 230. Here, the first and second contact holes 242 and 244 are also formed in the gate insulating film 222. Alternatively, when the gate insulating film 222 is patterned in the same shape as the gate electrode 230, the first and second contact holes 242 and 244 are formed only in the first brightness enhancement layer 240.

A source electrode 252 and a drain electrode 254 made of a conductive material such as metal are formed on the first brightness enhancement layer 240. A data line (not shown), a power line (not shown), and a second capacitor electrode (not shown) may be formed on the first brightness enhancement layer 240 in the second direction.

The source electrode 252 and the drain electrode 254 are spaced around the gate electrode 230 and contact both sides of the semiconductor layer 212 through the first and second contact holes 242 and 244, respectively . Although not shown, the data wiring extends along the second direction and intersects the gate wiring to define the pixel region, and the power wiring for supplying the high potential voltage is located apart from the data wiring. The second capacitor electrode is connected to the drain electrode 254 of the driving thin film transistor Td and overlaps with the first capacitor electrode so that the first luminance enhancement layer 240 between the first and second capacitor electrodes is formed as a dielectric layer, Capacitor.

The semiconductor layer 212 and the gate electrode 230, the source electrode 252 and the drain electrode 254 constitute a driving thin film transistor Td. The driving thin film transistor Td is formed on the semiconductor layer 212 And has a coplanar structure in which the gate electrode 230, the source electrode 252, and the drain electrode 254 are located.

Alternatively, the driving thin film transistor Td may have an inverted staggered structure in which a gate electrode is located below the semiconductor layer and a source electrode and a drain electrode are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Further, a switching thin film transistor (Ts in Fig. 2) having substantially the same structure as the driving thin film transistor Td is further formed on the substrate 210. [ The gate electrode 230 of the driving thin film transistor Td is connected to the drain electrode of the switching thin film transistor Ts and the source electrode 252 of the driving thin film transistor Td is connected to the power supply wiring Lt; / RTI > A gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor Ts are connected to the gate wiring and the data wiring, respectively.

A second brightness enhancement layer 260 including a second open carbon nano-tube 262 is formed on the entire surface of the substrate 210 on the source electrode 252 and the drain electrode 254. The second brightness enhancement layer 260 is flat on the top and has a drain contact hole 264 exposing the drain electrode 254 of the drive thin film transistor Td. Here, the drain contact hole 264 is formed directly on the second contact hole 244, but may be formed apart from the second contact hole 244.

The second brightness enhancement layer 260 includes an organic binder (not shown) and a second off-state carbon nanotube 262, and functions as a guide of light emitted from the light emitting diode D as well as an insulating layer .

The light emitting diode D includes a first electrode 270 located on the second brightness enhancement layer 260 and connected to the drain electrode 254 of the driving thin film transistor Td, And an organic light emitting layer 274 and a second electrode 276 which are stacked.

The first electrode 270 is made of a conductive material having a relatively large work function value and is formed separately for each pixel region (P in FIG. 2). For example, the first electrode 270 may be formed of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

The organic light emitting layer 274 may have a single layer structure of a light emitting material layer or may have a hole injection layer, a hole transporting layer, a light emitting material layer, an electron transporting layer, , And an electron injection layer.

The second electrode 276 is made of a material having a relatively large work function value and may be formed integrally with the entire display region including a plurality of pixel regions (P in FIG. 2). For example, the second electrode 276 may be formed of any one of aluminum (Al), magnesium (Mg), and aluminum-magnesium alloy (AlMg).

In addition, a bank 272 covering the edge of the first electrode 270 and having an opening exposing the center of the first electrode 270 may be further formed on the second brightness enhancement layer 260.

The holes from the first electrode 270 and the electrons from the second electrode 276 are combined at the organic light emitting layer 274 to form excitons and the excitons drop from the excited state to the ground state, ), That is, the organic light emitting layer 274 emits light.

The light from the organic light emitting layer 274 passes through the first and second brightness enhancement layers 240 and 260 and the substrate 210 in the organic light emitting diode display device 200 according to the second embodiment of the present invention, . That is, it is a bottom emission type organic light emitting diode display device. At this time, the light from the organic light emitting layer 274 is guided by the first and second open carbon nanotubes 241 and 262 of the first and second brightness enhancement layers 240 and 260, 200) increases.

That is, the light from the light emitting diode D passes through the space inside the first and second open carbon nanotubes 241 and 262 of the first and second brightness enhancement layers 240 and 260, . Accordingly, the amount of total reflection or diffuse reflection of light from the light emitting diode D decreases, and the amount of light directed toward the substrate 210 increases, so that the brightness of the organic light emitting diode display device 200 increases.

Referring again to FIG. 6, light from the light-emitting diode D is emitted from the first open carbon nanotube (241 in FIG. 7) and the second luminance enhancement layer (FIG. 7 7) is introduced through the one end of each of the second open carbon nanotubes (262 in FIG. 7) of the substrate 210 (FIG. 7) The straightness in the direction increases. Accordingly, the amount of total reflection or diffuse reflection of light from the light emitting diode D decreases, and the amount of light directed toward the substrate 210 increases, so that the brightness of the organic light emitting diode display device 200 increases.

In FIG. 7, it is shown that both the first and second open carbon nanotubes 241 and 262 are arranged perpendicular to the substrate 210. Alternatively, the first and second open carbon nanotubes 241 and 262 may be arranged in disorder. Even if the first and second open carbon nanotubes 241 and 262 are disorderly arranged, some of the first and second open carbon nanotubes 241 and 262 act as light paths because they are arranged perpendicularly or obliquely to the substrate 210.

The first and second open carbon nanotubes 241 and 262 are empty and both ends are open. That is, light enters the open end of the first and second open carbon nanotubes 241 and 262 and travels through the inner space, and the open end of the first and second open carbon nanotubes 241 and 262 So that the straightness of light increases. At this time, the first and second open carbon nanotubes 241 and 262 have a single layer or a double layer shell to form an inner space.

The first brightness enhancement layer 240 corresponds to the position of the interlayer insulation film (240 in FIG. 1) of a general organic light emitting diode display device, and the second brightness enhancement layer 260 corresponds to the position of the planarization layer (260) of FIG. 7, both the first brightness enhancement layer 240 and the second brightness enhancement layer 260 include the open carbon nanotubes 241 and 262. However, the present invention is not limited thereto. That is, only the first brightness enhancement layer 240 includes the opened carbon nanotubes 241, and a general planarization layer may be formed instead of the second brightness enhancement layer 260.

In other words, the organic light emitting diode display according to the first and second embodiments of the present invention includes the carbon nanotubes in which at least one of the interlayer insulating layer and the planarization layer is open, thereby functioning as a brightness enhancement layer, The brightness of the organic light emitting diode display device is increased without increasing the voltage.

- Third Embodiment -

8 is a schematic cross-sectional view of an organic light emitting diode display device according to a third embodiment of the present invention.

8, the organic light emitting diode display 300 according to the third exemplary embodiment of the present invention includes a driving thin film transistor Td, a light emitting diode D connected to the driving thin film transistor Td, And a brightness enhancement layer 380 covering the driving thin film transistor Td.

The driving thin film transistor Td includes a semiconductor layer 312, a gate electrode 330, a source electrode 352 and a drain electrode 354. [

A semiconductor layer 312 is formed on a substrate 310 made of glass or plastic. For example, the semiconductor layer 312 may be made of an oxide semiconductor material. Alternatively, the semiconductor layer 312 may be made of polycrystalline silicon. In this case, impurities may be doped on both edges of the semiconductor layer 312.

A gate insulating layer 322 made of an insulating material is formed on the entire surface of the substrate 310 on the semiconductor layer 312. The gate insulating film 322 may be made of an inorganic insulating material such as silicon oxide or silicon nitride.

A gate electrode 330 made of a conductive material such as metal is formed on the gate insulating layer 322 in correspondence with the center of the semiconductor layer 312. A gate wiring (not shown) and a first capacitor electrode (not shown) may be formed on the gate insulating film 322. The gate wiring may extend along the first direction, and the first capacitor electrode may be connected to the gate electrode 330.

The gate insulating film 322 is formed on the entire surface of the substrate 310. The gate insulating film 322 may be patterned to have the same shape as the gate electrode 330. [

An interlayer insulating layer 340 made of an insulating material is formed on the entire surface of the substrate 310 on the gate electrode 330. The interlayer insulating film 340 may be formed of an inorganic insulating material such as silicon oxide or silicon nitride or an organic insulating material such as benzocyclobutene or photo-acryl.

The interlayer insulating film 340 has first and second contact holes 342 and 344 that expose both upper surfaces of the semiconductor layer 112. The first and second contact holes 342 and 344 are spaced apart from the gate electrode 330 on both sides of the gate electrode 330. Here, the first and second contact holes 342 and 344 are also formed in the gate insulating film 322. Alternatively, when the gate insulating film 322 is patterned in the same shape as the gate electrode 330, the first and second contact holes 342 and 344 are formed only in the interlayer insulating film 340.

A source electrode 352 and a drain electrode 354 are formed of a conductive material such as metal on the interlayer insulating layer 340. Further, a data line (not shown), a power supply line (not shown), and a second capacitor electrode (not shown) may be formed on the interlayer insulating layer 340 in the second direction.

The source electrode 352 and the drain electrode 354 are spaced about the gate electrode 330 and contact both sides of the semiconductor layer 312 through the first and second contact holes 342 and 344 . Although not shown, the data wiring extends along the second direction and intersects the gate wiring to define the pixel region, and the power wiring for supplying the high potential voltage is located apart from the data wiring. The second capacitor electrode is connected to the drain electrode 354 of the driving thin film transistor Td and overlaps the first capacitor electrode so that the interlayer insulating film 340 between the first and second capacitor electrodes forms a storage capacitor .

The semiconductor layer 312 and the gate electrode 330, the source electrode 152 and the drain electrode 354 constitute a driving thin film transistor Td. The driving thin film transistor Td is formed on the semiconductor layer 312 And has a coplanar structure in which the gate electrode 330, the source electrode 352, and the drain electrode 354 are located.

Alternatively, the driving thin film transistor Td may have an inverted staggered structure in which a gate electrode is located below the semiconductor layer and a source electrode and a drain electrode are located above the semiconductor layer. In this case, the semiconductor layer may be made of amorphous silicon.

Further, a switching thin film transistor (Ts in Fig. 2) having substantially the same structure as the driving thin film transistor Td is further formed on the substrate 310. [ The gate electrode 330 of the driving thin film transistor Td is connected to the drain electrode (not shown) of the switching thin film transistor Ts and the source electrode 352 of the driving thin film transistor Td is connected to the power supply wiring Lt; / RTI > A gate electrode (not shown) and a source electrode (not shown) of the switching thin film transistor Ts are connected to the gate wiring and the data wiring, respectively.

A planarization layer 360 is formed on the entire surface of the substrate 310 on the source electrode 352 and the drain electrode 354. The planarization layer 360 has a flat upper surface and a drain contact hole 364 exposing the drain electrode 354 of the driving thin film transistor Td. Here, the drain contact hole 364 is formed directly on the second contact hole 344, but may be formed apart from the second contact hole 344.

The light emitting diode D includes a first electrode 370 located on the planarization layer 360 and connected to the drain electrode 354 of the driving TFT Td, A light emitting layer 374, and a second electrode 376.

The first electrode 370 is formed of a conductive material having a relatively large work function value and is formed separately for each pixel region (P in FIG. 2). For example, the first electrode 370 may be made of a transparent conductive material such as indium-tin-oxide (ITO) or indium-zinc-oxide (IZO).

The organic light emitting layer 374 may have a single layer structure of a light emitting material layer or may have a hole injection layer, a hole transporting layer, a light emitting material layer, an electron transporting layer, , And an electron injection layer.

The second electrode 376 is made of a material having a relatively large work function value and may be formed integrally with the entire display region including a plurality of pixel regions P. [ For example, the second electrode 376 may be formed of any one of aluminum (Al), magnesium (Mg), and aluminum-magnesium alloy (AlMg).

At this time, the second electrode 376 may have a relatively thin thickness through which light is transmitted, and the light transmittance of the second electrode 392 may be about 45-50%. That is, the organic light emitting diode display 300 according to the third embodiment of the present invention includes a top emission type in which light from the organic emission layer 374 passes through the second electrode 392 to display an image, to be.

In order to improve the light efficiency, the first electrode 370 may further include a reflective layer (not shown) made of an opaque conductive material, and may have a multi-layer structure including a transparent conductive electrode layer and a reflective layer of an opaque conductive material. For example, the reflective layer may be formed of an aluminum-palladium-copper (APC) alloy, and the first electrode 370 may have a triple-layer structure of ITO / APC / ITO.

A bank 372 covering the edge of the first electrode 370 and having an opening exposing the center of the first electrode 370 may be further formed on the planarization layer 360.

The brightness enhancement layer 380 covers the light emitting diode D and includes a opened carbon nano-tube 382. That is, the brightness enhancement layer 380 is located on the second electrode 376 and corresponds to the front surface of the substrate 310.

The brightness enhancing layer 380 includes carbon nanotubes 382 that are turned off with an organic binder (not shown) and serves as a guide for light emitted from the light emitting diode D.

The holes from the first electrode 370 and the electrons from the second electrode 376 are combined at the organic light emitting layer 374 to form an exciton and the excitons drop from the excited state to the ground state, ), That is, the organic light emitting layer 374 emits light.

As described above, the organic light emitting diode display 300 according to the third embodiment of the present invention is configured such that light from the organic light emitting layer 374 passes through the second electrode 376 and the brightness enhancement layer 380, Is displayed. At this time, the light from the organic light emitting layer 374 is guided by the open carbon nanotubes 382 of the brightness enhancement layer 380, thereby increasing the brightness of the organic light emitting diode display device 300.

Referring again to FIG. 6, light from the light emitting diode D flows into the inner space through one end of the open carbon nanotubes (382 in FIG. 8) of the brightness enhancement layer (380 in FIG. 8) Is guided in the direction of the outer surface of the brightness enhancing layer 380, the straightness of light increases. Accordingly, the amount of total reflection or diffuse reflection of light from the light emitting diode D decreases, and the amount of light directed toward the outer surface of the brightness enhancement layer 380 increases, so that the brightness of the organic light emitting diode display device 300 increases do.

In FIG. 8, it is shown that all of the open carbon nanotubes 382 are arranged perpendicular to the substrate 310. Alternatively, the open carbon nanotubes 382 may be arranged in disorder. Even if the open carbon nanotubes 382 are disorderly arranged, some of the carbon nanotubes 382 act as paths of light because they are arranged perpendicularly or obliquely to the substrate 310.

The opened carbon nanotubes 382 are empty and have both ends open. That is, light enters into the open end of the opened carbon nanotube 382, travels through the inner space, and is released to the open end of the opened carbon nanotube 382, so that the straightness of light increases. At this time, the open carbon nanotubes 382 have a single layer or a double layer shell to form an inner space.

The upper emission type organic light emitting diode display 300 according to the third embodiment of the present invention includes a brightness enhancement layer 370 including an open carbon nanotube 382 located above the second electrode 376 and providing a light path, The luminance of the organic light emitting diode display device 300 increases without increasing the driving voltage.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention as defined in the appended claims. It can be understood that

100, 200, 300: organic light emitting diode display device
110, 210, 310: substrate 112, 212, 312: semiconductor layer
122, 222, 322: gate insulating film 130, 230, 330: gate electrode
140, 340: interlayer insulating film 152, 252, 352: source electrode
154, 254, 354: drain electrode 170, 270, 370: first electrode
172, 272, 372: banks 174, 274, 374: organic light emitting layer
176, 276, 376: second electrodes 160, 240, 260, 280:
162, 241, 262, 282: open carbon nanotubes
360: planarization layer Td: driving thin film transistor
Ts: switching thin film transistor D: light emitting diode

Claims (12)

An organic binder;
Open carbon nanotubes
And a second electrode layer.
The method according to claim 1,
Wherein the open carbon nanotubes are arranged in the same direction.
Claims [1]
A thin film transistor located on the substrate;
A light emitting diode disposed on the thin film transistor and connected to the thin film transistor;
And a first brightness enhancement layer disposed between the thin film transistor and the light emitting diode and including a first open carbon nanotube
And an organic light emitting diode (OLED) display device.
The method of claim 3,
Wherein the first open carbon nanotube is arranged perpendicular to the substrate.
The method of claim 3,
Wherein the first brightness enhancement layer includes a contact hole exposing an electrode of the thin film transistor, and the light emitting diode is connected to the thin film transistor through the contact hole.
The method of claim 3,
The light emitting diode includes a first electrode connected to the thin film transistor, an organic light emitting layer above the first electrode, and a second electrode above the organic light emitting layer,
Wherein light from the organic light emitting layer passes through the first brightness enhancement layer and the substrate to display an image.
The method of claim 3,
The thin film transistor includes a semiconductor layer, a gate insulating film on the semiconductor layer, a gate electrode on the gate insulating film, a second brightness enhancement layer covering the gate electrode, and a second brightness enhancement layer, And a source electrode and a drain electrode, respectively,
And the second brightness enhancement layer comprises a second open carbon nanotube.
8. The method of claim 7,
And the second open carbon nanotube is arranged perpendicular to the substrate.
Claims [1]
A thin film transistor located on the substrate;
A light emitting diode disposed on the thin film transistor and connected to the thin film transistor;
A brightness enhancement layer including the carbon nanotubes that cover the light emitting diode and open,
And an organic light emitting diode (OLED) display device.
10. The method of claim 9,
Wherein the open carbon nanotubes are arranged perpendicular to the substrate.
11. The method of claim 10,
The light emitting diode includes a first electrode connected to the thin film transistor, an organic light emitting layer above the first electrode, and a second electrode above the organic light emitting layer,
Wherein light from the organic light emitting layer passes through the second electrode and the brightness enhancement layer to display an image.
11. The method of claim 10,
Wherein the first electrode includes a transparent conductive electrode layer and a reflective layer.

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