KR20100025257A - Organic light emitting display - Google Patents

Abstract

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic light emitting display device in which a blue EL layer having a double structure is formed to improve the life of blue and to extend the life of the panel as a whole. A cathode formed correspondingly, the conductive line formed between the anode and the cathode to form an electric field with the anode and the cathode, a first blue EL layer formed between the anode and the conductive line, the conductive line and the cathode And a second blue EL layer formed therebetween.

Description

Organic light emitting display device {ORGANIC LIGHT EMITTING DISPLAY}

The present invention relates to an organic light emitting display device, and more particularly to an organic light emitting display device to improve the life of the panel.

Recently, a flat panel display (CRT) having a merit of small size and light weight by solving problems of weight and size of a cathode ray tube (CRT) has attracted attention. Such flat panel displays include Liquid Crystal Display (LCD), Organic Electro Luminescence Display (OELD), Field Emitter Display (FED) and Plasma Display (PDP). Panel).

Among the flat panel display devices, the organic light emitting display device has a wider operating temperature range than other flat panel display devices, is resistant to shock and vibration, has a wide viewing angle, and has a fast response speed, thereby providing clean moving images. It is attracting attention as a next-generation flat panel display device in the future.

Recently, among the various display devices that implement various information on the screen, an organic electroluminescence (Electro-Luminescence) display device that can be thinned like a paper is attracting attention.

An organic light emitting display device is a self-luminous device using a thin organic light emitting layer between electrodes, which is called an organic EL or organic light emitting diode (OLED) display device and uses an OLED display device hereinafter. OLED displays have advantages such as low power consumption, thinness, and self-luminous, compared to liquid crystal displays, but have shortcomings.

OLED displays are being developed based on an active matrix type suitable for displaying moving images by independently driving each of three color (R, G, B) sub-pixels constituting one pixel.

1 is a cross-sectional view illustrating an organic light emitting display device according to the prior art.

In general, as shown in FIG. 1, an organic light emitting display device includes an anode 2 formed on a substrate 1, an organic EL layer 10 formed on the anode 2, and the organic material. It consists of a cathode 8 formed on the EL layer 10 and a packaging plate (not shown) bonded to the substrate 1 on the cathode 8 so as to face the substrate 1.

 In this case, the organic EL layer 10 has a laminated structure of a hole injection layer 3, a hole transport layer 4, a light emitting layer 5, an electron transport layer 6, and an electron injection layer 7.

When an electric field is applied to the anode 2 and the cathode 8 of the organic light emitting display device configured as described above, electrons are injected from the cathode 8 into the organic EL layer 10, and holes from the anode 2 are organic EL layers. Is injected into (10).

That is, electrons generated in the electron injection layer 7 are applied to the light emitting layer 5 via the electron transport layer 6, and holes formed in the hole injection layer 3 are identically emitted through the hole transport layer 4. Is applied as (5). Electrons and holes encountered in the emission layer 5 form an exton, and the exons thus formed emit light through a recombination process and fall to a low energy level.

On the other hand, the fabrication process of the general organic light emitting display device is an anode (2), a hole injection layer (3), a hole transport layer (4), a light emitting layer (5), an electron transport layer (6), an electron injection layer (7), a cathode ( 8), first, an indium tin oxide (ITO), which is a transparent conductive material, is deposited and patterned on the substrate 1 to form an anode 2.

Subsequently, copper (phthalate) phthalocyanine (copper (II) phthalocyanine) is deposited on the anode 2 to form a hole injection layer 3, and NPD (N, N-di (naphthalen) is formed thereon. -1-yl) -N, N'-diphenylbenzidine) is deposited to a thickness of 30 to 60 nm to form a hole transport layer (4).

Subsequently, a light emitting layer 5 emitting green light, red light, and blue light is selectively formed on the hole transport layer 4, and each light emitting material is formed by using a unique light emitting material, or a light emitting material is applied to a host material. Can be formed by doping.

Subsequently, the electron transport layer 6 and the electron injection layer 7 are sequentially vacuum deposited on the light emitting layer 5.

The cathode 8 is formed by depositing and patterning indium tin oxide (ITO), which is a transparent conductive material, on the entire surface including the electron injection layer 7.

However, the organic light emitting diode display according to the related art has the following problems.

That is, the life of B (blue) among the three color (R, G, B) sub-pixels constituting one pixel in an organic light emitting display device is twice or more and four times shorter than that of R (red) and G (green). When manufacturing a panel having a large number of three-color sub-pixels, the lifetime is shortened due to an absolute influence on the panel life.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems and provides an organic light emitting display device in which a blue EL layer having a double structure is formed to improve the life of blue and thereby extend the life of the panel as a whole. There is this.

An organic light emitting display device according to the present invention includes an anode formed on a substrate, a cathode formed to correspond to the anode at regular intervals, and a conductive line formed between the anode and the cathode to form an electric field with the anode and the cathode; And a first blue EL layer formed between the anode and the conductive line, and a second blue EL layer formed between the conductive line and the cathode.

In addition, an organic light emitting display device according to another exemplary embodiment of the present invention includes an anode formed on a substrate, a cathode formed to correspond to the anode at regular intervals, and formed between the anode and the cathode to form the anode, the cathode, and the electric field. And a first blue EL layer, a red EL layer, and a green EL layer formed between the anode and the conductive line, and a second blue EL layer formed between the conductive line and the cathode. It is done.

An organic light emitting display device according to the present invention has the following effects.

That is, the blue EL layer is formed in a double structure, and the power is connected to the first blue EL layer, and when the life of the first blue EL layer reaches a certain level, the power is turned off and the power is connected to the second blue EL layer. As a result, the lifetime of the blue EL layer as a whole can be extended to extend the lifetime of the panel.

Hereinafter, an organic light emitting display device according to the present invention will be described in detail with reference to the accompanying drawings.

2 is a cross-sectional view illustrating an organic light emitting display device according to a first embodiment of the present invention.

As shown in FIG. 2, the organic light emitting diode display according to the first embodiment of the present invention corresponds to an anode 110 formed on the substrate 100 at regular intervals from the anode 110. A cathode 120 to be formed, a conductive line (CGL) 130 formed between the anode 110 and the cathode 120 to form an electric field with the anode 110 and the cathode 120, A first blue EL layer 140 formed between the anode 110 and the conductive line 130 and a second blue EL layer 150 formed between the conductive line 130 and the cathode 120. It is.

 In this case, the first blue EL layer 140 may include a first hole injection layer 141, a first hole transport layer 142, a first light emitting layer 143, a first electron transport layer 144, and a first electron injection layer ( 145) laminated structure.

In addition, the second blue EL layer 150 may include a second hole injection layer 151, a second hole transport layer 152, a second light emitting layer 153, a second electron transport layer 154, and a second electron injection layer ( 155) laminated structure.

Here, although the conductive line 130 has been described using a hot dip galvanizing line (CGL) in an embodiment of the present invention, the conductive layer 130 is not limited thereto, and examples of the conductive layer 130 include Mo, Ti, Cu, AlNd, Al, Cr, Metal materials such as Mo alloys, Cu alloys, Al alloys, and the like may be used in a single layer or a double or more multilayer structure.

On the other hand, the conductive line 130 is formed to have a thickness of 20 ~ 100Å.

In addition, the anode 110 is formed of a metal having high reflectivity such as Al, Al / Li, Ma / Ag, Al / Nd, and the cathode 120 is formed of a conductive material having a transmissive or semi-transparent material, and a transparent material. Indium Tin Oxide (ITO), Tin Oxide (TO), Indium Zinc Oxide (IZO) or Indium Tin Zinc Oxide (ITZO) is used as the furnace. As the semi-permeable material, forming a thin film of LiF / Al, CsF / Al, Mg: Ag, Ca / Ag, Ca: Ag, LiF / Ma: Ag, LiF / Ca / Ag, LiF / Ca: Ag desirable.

In addition, when the cathode 120 is formed of a transparent conductive layer, an auxiliary electrode (not shown) may be provided on the cathode 120 to lower the resistance of the cathode 120. The auxiliary electrode (not shown) is a conductive metal material having a lower resistance value than that of the cathode 120, and includes silver (Ag), aluminum (Al), chromium (Cr), molybdenum (Mo), and the like. 2 are formed in the non-light emitting regions of the light emitting layers 143 and 154.

In the organic light emitting diode display according to the first exemplary embodiment of the present invention configured as described above, first, when power is applied to the anode 110 and the conductive line 130, electrons from the conductive line 130 are first blue EL layer 140. ), And holes are injected from the anode 110 into the first blue EL layer 140.

That is, electrons generated in the first electron injection layer 145 are applied to the first light emitting layer 143 via the first electron transport layer 144, and holes formed in the first hole injection layer 141 are formed in the first electron injection layer 141. The same is applied to the first light emitting layer 143 via the hole transport layer 142. Electrons and holes encountered in the first emission layer 143 form an exton, and the exons thus formed emit light through a recombination process.

Subsequently, when the life of the first blue EL layer 140 reaches about 50%, when the power is turned off and power is applied to the conductive line 130 and the cathode 120, electrons from the cathode 120 are second blue. The hole is injected into the EL layer 150, and holes are injected from the conductive line 130 into the second blue EL layer 150.

That is, electrons generated in the second electron injection layer 155 are applied to the second emission layer 153 via the second electron transport layer 154, and holes formed in the second hole injection layer 151 are second. The same is applied to the second light emitting layer 153 via the hole transport layer 152. Electrons and holes encountered in the second emission layer 153 form an exton, and the exons thus formed emit light through a recombination process.

In general, since the life of an organic light emitting display device is considered to be finished after the life of each EL layer is about 50%, the life of the organic light emitting display device can be extended by twice as much as in the prior art.

Table 1 below shows the voltage and the luminous efficiency when the conductive line 130 is used in the first embodiment of the present invention. Here, Reference is a prior art as a reference.

 CGL Volt (V) Efficiency CIE EQE (%) cd / A lm / W x y Reference 5.5 6.2 3.5 0.138 0.205 4.4 CGL (Li2O_10Å) 11.4 5.7 1.6 0.137 0.217 4.1 CGL (Li2O_30Å) 6.4 13.9 6.8 0.132 0.253 9.2

As shown in Table 1, it can be seen that the best effect is obtained when the first embodiment of the present invention has a thickness of 30 kHz of the conductive line.

3 is a graph showing the life of the display device when the conductive line is used based on Table 1. FIG.

As shown in FIG. 3, it can be seen that when the conductive line has a thickness of 30 μs, it has a higher lifetime than the conventional reference.

4 is a cross-sectional view illustrating an organic light emitting display device according to a second exemplary embodiment of the present invention.

As shown in FIG. 4, the organic light emitting diode display according to the second exemplary embodiment of the present invention corresponds to an anode 310 formed on the substrate 300 at regular intervals from the anode 310. A cathode 320 to be formed, a conductive line (CGL) 330 formed between the anode 310 and the cathode 320 to form an electric field with the anode 310 and the cathode 320, The first blue EL layer 340, the red EL layer 350, and the green EL layer 360 formed between the anode 310 and the conductive line 330, and between the conductive line 330 and the cathode 320. And a second blue EL layer 370 formed on the substrate.

That is, the organic light emitting display device according to the second embodiment of the present invention includes the red EL layer 350 and the green EL layer 360 as compared with the first embodiment, and the red EL layer 350 and the green EL. Except for forming the second blue EL layer 370 on the layer 360, the remaining part has the same configuration.

 In this case, the first blue EL layer 340 may include a first hole injection layer 341, a first hole transport layer 342, a first light emitting layer 343, a first electron transport layer 344, and a first electron injection layer ( 345 is a laminated structure.

In addition, the second blue EL layer 370 may include a second hole injection layer 371, a second hole transport layer 372, a second light emitting layer 373, a second electron transport layer 374, and a second electron injection layer ( 375) laminated structure.

The green EL layer 360 is formed by stacking a third hole injection layer 361, a third hole transport layer 362, a third light emitting layer 363, a third electron transport layer 364, and a third electron injection layer 365. Made of structure.

In addition, the red EL layer 350 may include a fourth hole injection layer 351, a fourth hole transport layer 352, a fourth light emitting layer 353, a fourth electron transport layer 354, and a fourth electron injection layer 355. It consists of a laminated structure.

In the organic light emitting diode display according to the second exemplary embodiment of the present invention configured as described above, the lifespan of the first blue EL layer 340 reaches about 50% as in the first exemplary embodiment. ) And the cathode 320, power is injected from the cathode 320 to the second blue EL layer 370, and holes from the conductive line 330 to the second blue EL layer 370. Is injected.

Meanwhile, the second blue EL layer 370, the red EL layer 350, and the green EL layer 360 are driven differently from each other.

In order to prolong the life of the pixel, which is the biggest disadvantage in manufacturing the organic light emitting display device according to the second embodiment of the present invention, a red / green pixel is implemented in 2-stock. Independent driving method is provided by connecting power to each stock device.

Subsequently, a blue element is attached to the second stock of RGB pixels, and when the blue color is realized, only one third of the power is supplied by driving the blue element attached to red and green together. When the blue color and red color are implemented, the blue stock attached to the green is simultaneously driven to apply only 1/2 of the power, and the same method is used when implementing the blue / red. Apply 1/2 power each to make same color.

In addition, when the life span of blue 1-stock is over, a blue 2-stock device is used. As a result, the life span of the panel is improved, and in the case of blue, the color of the first blue EL layer 340 and the color of the second blue EL layer 370 are the same. To this end, the thickness of the hole injection layer, the hole transport layer, and the electron transport layer should be adjusted to give a cavity, and the blue devices entering the red and green colors need to be optimized for the cavity as well. In order to use the transparent conductive line 330 to the electrode should be used.

5 is a graph comparing the lifespan between the organic light emitting display according to the second embodiment of the present invention and the conventional organic light emitting display.

As shown in FIG. 5, the result of the present invention performed at 5000 nit and 25 ° C. shows that the life of the present invention is further improved.

The present invention described above is not limited to the above-described embodiments and the accompanying drawings, and various substitutions, modifications, and changes can be made without departing from the technical spirit of the present invention. It will be evident to those who have knowledge of.

1 is a cross-sectional view illustrating an organic light emitting display device according to the related art.

2 is a cross-sectional view illustrating an organic light emitting display device according to a first embodiment of the present invention.

3 is a graph showing the life of the display device when using the conductive line based on Table 1

4 is a cross-sectional view illustrating an organic light emitting display device according to a second exemplary embodiment of the present invention.

5 is a graph comparing the lifespan between the organic light emitting display according to the second embodiment of the present invention and the conventional organic light emitting display;

Explanation of symbols for the main parts of the drawings

100: substrate 110: anode

120: cathode 130: conductive line

140: first blue EL layer 150: second blue EL layer

Claims (4)

An anode formed on the substrate, A cathode formed to correspond to the anode at regular intervals; Conductive lines formed between the anode and the cathode to form an electric field with the anode and the cathode; A first blue EL layer formed between the anode and the conductive line, And a second blue EL layer formed between the conductive line and the cathode. The organic light emitting display device of claim 1, wherein the conductive line is a hot dip galvanizing line. The organic light emitting display device of claim 1, wherein the conductive line has a thickness of about 20 μs to about 100 μs. An anode formed on the substrate, A cathode formed to correspond to the anode at regular intervals; Conductive lines formed between the anode and the cathode to form an electric field with the anode and the cathode; A first blue EL layer, a red EL layer and a green EL layer formed between the anode and the conductive line; And a second blue EL layer formed between the conductive line and the cathode.

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