KR102138906B1 - Organic light emitting display device using white organic light emitting element and color filter - Google Patents

Abstract

The present invention relates to an organic light emitting display device capable of improving light efficiency by using a white organic light emitting element and a color filter, and a plurality of first electrodes respectively connected to a plurality of thin film transistors formed on a first substrate A thin film transistor substrate on which a white organic light emitting element is formed between the first and second electrodes; And a color filter substrate disposed opposite to the thin film transistor substrate, wherein the color filter substrate has a second substrate having a plurality of recesses formed at positions corresponding to the first electrodes, and on the second substrate. It characterized in that it comprises a high-viscosity flattening film formed and a plurality of color filter layers formed on the high-viscosity flattening film.

Description

ORGANIC LIGHT EMITTING DISPLAY DEVICE USING WHITE ORGANIC LIGHT EMITTING ELEMENT AND COLOR FILTER

The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device capable of improving light efficiency using a white organic light emitting element and a color filter.

Recently, various flat panel display devices capable of reducing weight and volume, which are disadvantages of a cathode ray tube, have been developed. Such a flat panel display includes a liquid crystal display (Liquid Crystal Display: hereinafter referred to as "LCD"), a field emission display (FED), a plasma display panel (hereinafter referred to as "PDP") and an electric field. And an electroluminescence device.

The PDP is attracting attention as a display device most advantageous for a large screen while being light and simple due to its simple structure and manufacturing process, but has a disadvantage of low luminous efficiency, low luminance and high power consumption. In addition, the liquid crystal display device is one of the most widely used flat panel display devices, but has a problem in that the viewing angle is narrow and the response speed is low. The electroluminescent device is roughly classified into an inorganic light emitting display device and an organic light emitting display device according to the material of the light emitting layer. Among them, the organic light emitting display device is a self-luminous device that emits light by itself, and has a high response speed, high luminous efficiency, high brightness, and large viewing angle. have.

In the organic light emitting display device, three pixels of red, green, and blue are used in the display driving mode. Recently, a method of using white light is being considered as one of the most effective methods to reduce power efficiency. An organic light emitting display device in which a color filter is bonded is known.

However, in the organic light emitting device, a structure such as a light waveguide is formed between the substrate and the organic light emitting device. Due to this, as the light generated in the light emitting layer is totally internally reflected on the surface of the organic light emitting device, the interface with the electrode or the color filter layer, a significant amount of light is not emitted to the outside and is lost inside, resulting in a very low light extraction efficiency. there was.

In order to solve this problem, a method of increasing light extraction efficiency by attaching a micro lens array or a light diffusion film to the outer surface of the display device has been proposed. However, according to this method, there is another problem that it is difficult to apply to the display device due to the fact that the light efficiency improvement is only about 1.6 times, so the limitation is clear, and the color change and the interference color according to the viewing angle occur due to the diffraction phenomenon.

Accordingly, an object of the present invention is to provide an organic light emitting display device capable of solving the above-described problems and improving light efficiency using a white organic light emitting device and a color filter.

In order to achieve the above object, in the organic light emitting display device according to the present invention, a white organic light emitting device is provided between a plurality of first electrodes and a second electrode respectively connected to a plurality of thin film transistors formed on a first substrate. A thin film transistor substrate formed; And a color filter substrate disposed opposite to the thin film transistor substrate, wherein the color filter substrate has a second substrate having a plurality of recesses formed at positions corresponding to the first electrodes, and on the second substrate. It characterized in that it comprises a high-viscosity flattening film formed and a plurality of color filter layers formed on the high-viscosity flattening film.

In the above configuration, the high-viscosity planarization film is characterized by having a refractive index in the range of 1.2 to 1.4.

In addition, the high-viscosity planarization film is poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-cotetrafluoroethylene] (Poly[4,5-difluoro- 2,2-bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene]), poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), poly(2,2 ,3,4,4,4-hexafluorobutyl acrylate), poly(2,2,2-trifluoromethyl acrylate), poly(2,2,2-trifluoromethacrylate acrylate), It is characterized in that it is selected from any one of poly (1,1,1,3,3,3-hexafluorobutyl acrylate).

Further, the plurality of color filter layers are formed corresponding to the recesses of the second substrate.

In addition, the organic light emitting display device may further include a reflective film formed between the thin film transistor layer and the first electrodes.

Further, the plurality of first electrodes are respectively connected to the thin film transistors through contact holes formed in the reflective film.

Also, first electrodes adjacent to each other among the plurality of first electrodes may be separated by a bank.

According to the organic light emitting display device according to the present invention, an air gap is formed by a concave portion formed at a position of the second substrate corresponding to the color filter layers, and a high-viscosity flattening film is formed on the upper side, so that the air layer in the air gap According to the difference in refractive index between the high-viscosity material layer, an effect of increasing light efficiency may be obtained at positions of the red color filter layer, the green color filter layer, and the blue color filter layer.

1 is a circuit diagram showing one pixel of an organic light emitting display device according to an exemplary embodiment of the present invention,
2 is a cross-sectional view showing a portion of an organic light emitting display device according to an exemplary embodiment of the present invention shown in FIG. 1,
3 is a cross-sectional view illustrating in more detail the connection relationship between the thin film transistor layer and the first electrode layer illustrated in FIG. 2.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. Throughout the specification, the same reference numerals denote the same components.

1 to 3, an organic light emitting display device according to an exemplary embodiment of the present invention will be described. 1 is an example of a circuit diagram showing one pixel of an organic light emitting display device according to an exemplary embodiment of the present invention, and FIG. 2 shows a partial area of an organic light emitting display device according to an exemplary embodiment of the present invention shown in FIG. 1. 3 is a cross-sectional view illustrating in more detail the connection relationship between the thin film transistor layer and the first electrode layer illustrated in FIG. 2.

Referring to FIG. 1, one pixel of an organic light emitting display device according to an exemplary embodiment of the present invention includes a cell driver DU connected to a gate line GL, a data line DL and a power line PL, and a cell driver And a white organic light emitting device (WOLED) connected between (DU) and ground (GND).

The cell driver DU includes a switch thin film transistor T1 connected to a gate line GL and a data line DL, a switch thin film transistor T1, a power line PL, and a white organic light emitting device WOLED. A driving thin film transistor T2 connected to one electrode and a storage capacitor C connected between the power line PL and the drain electrode of the switch thin film transistor T1 are provided.

The gate electrode of the switch thin film transistor T1 is connected to the gate line GL, the source electrode is connected to the data line DL, and the drain electrode is connected to the gate electrode and the storage capacitor C of the driving thin film transistor T2. . The source electrode of the driving thin film transistor T2 is connected to the power supply line PL, and the drain electrode is connected to the first electrode of the white organic light emitting element WOLED. The storage capacitor C is connected between the power supply line PL and the gate electrode of the driving thin film transistor T2.

When the scan pulse is supplied to the gate line GL, the switch thin film transistor T1 is turned on to supply the data signal supplied to the data line DL to the storage capacitor C and the gate electrode of the driving thin film transistor T2. do. The driving thin film transistor T2 controls the current I supplied from the power supply line PL to the white organic light emitting device WOLED in response to the data signal supplied to the gate electrode, thereby increasing the amount of light emitted from the white organic light emitting device WOLED. Control. In addition, even when the switch thin film transistor T1 is turned off, the driving thin film transistor T2 is supplied with a constant current I until the data signal of the next frame is supplied by the voltage charged in the storage capacitor C. The organic light emitting device (WOLED) maintains light emission.

2 and 3, an organic light emitting display device according to an exemplary embodiment of the present invention includes a thin film transistor substrate TFT_S and a color filter substrate CF_S attached to the thin film transistor substrate TFT_S by an adhesive layer 300. Includes.

The thin film transistor array substrate TFT_S includes a first substrate 100 made of an insulating material, a gate electrode G formed on the first substrate 100 and extending from a gate line, and a gate covering the gate electrode G The insulating film GI, the semiconductor active layer A formed in the region corresponding to the gate electrode G on the gate insulating film GI, and a portion of the semiconductor active layer A are exposed, and separated from each other on the gate insulating film GI The formed source electrode S and the drain electrode D are included.

In the above embodiment, although the thin film transistor T2 is described as an example of a thin film transistor having a gate bottom structure in which the gate electrode G is formed under the source electrode S and the drain electrode D, as an example. , It should be understood that the present invention is not limited to this, and also includes a thin film transistor of a gate top structure in which the gate electrode is formed on the source/drain region. The thin film transistor of the gate top structure (gate top structrue) is a known configuration, detailed description thereof will be omitted.

The thin film transistor array substrate TFT_S also covers the first passivation layer PAS1 made of an inorganic material to cover the source electrode S and the drain electrode D, and the driving thin film transistor T2 to cover the entire surface and planarize the surface. It further includes a second protective film (PAS2) made of an organic material for.

Here, the semiconductor active layer (A) is taken as an example where the semiconductor active layer (A) is also formed of a silicon semiconductor active layer. However, the semiconductor active layer (A) may be formed of an oxide semiconductor. In this case, an etch stopper is formed on the semiconductor active layer (A) so that the semiconductor active layer is not exposed. The oxide semiconductor is formed of, for example, an oxide containing at least one metal selected from Zn, Cd, Ga, In, Sn, Hf, and Zr. The thin film transistor including the oxide semiconductor has advantages of higher charge mobility and lower leakage current characteristics than the thin film transistor including the silicon semiconductor active layer. In addition, a thin film transistor including an oxide semiconductor can be processed at a low temperature, and has an advantage of large area.

The thin film transistor array substrate TFT_S also includes a reflective film 120 formed on the front surface of the second passivation layer PAS2. The contact hole CH is formed on the first passivation layer PAS1, the second passivation layer PAS2, and the reflective layer 120 to expose the drain electrode D of the thin film transistor T2.

The thin film transistor array substrate TFT_S is also formed on the reflective film 120 and includes a plurality of first electrodes 130R, 130G, and 130B separated by the banks 140, and the banks 140 and the plurality of agents. It includes a white organic light emitting device 150 covering the one electrode (130R, 130G, 130B), and a second electrode 160 formed on the white organic light emitting device 150. The plurality of first electrodes 130R, 130G, and 130B may be formed to have different thicknesses. A third passivation layer 170 for protecting the second electrode 160 may be formed on the second electrode 160.

The color filter substrate CF_S includes a second substrate 200 having concave portions 200a formed corresponding to the first electrodes 130R, 130G, and 130B of the thin film transistor array substrate TFT_S, and concave portions 200a. It includes a high-viscosity planarization film 210 formed on the formed second substrate 200, and color filter layers 220R, 220G, and 220B formed on the high-viscosity planarization film 210.

The high-viscosity planarization film 210 may be selected from materials having a refractive index in the range of 1.2 to 1.4. An example of the high-viscosity planarization film 210 is poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-cotetrafluoroethylene represented by Chemical Formula 1] ( Poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene]), poly(2,2,3,3,4,4,4- represented by the formula (2) Heptafluorobutyl acrylate), poly(2,2,3,4,4,4-hexafluorobutyl acrylate) represented by formula (3), poly(2,2,2-triplo) represented by formula (4) Oromethyl methacrylate), poly(2,2,2-trifluoromethel acrylate) represented by formula 5, poly(1,1,1,3,3,3-hexafluoro represented by formula 6) Butyl acrylate).

The color filter layers 220R, 220G, and 220B include a red color filter layer 200R, a green color filter layer 220G, and a blue color filter layer 220B, and are bounded by the black matrices 230. The color filter layers 220R, 220G, and 220B are formed corresponding to the concave portions 200a of the second substrate 200 and the first electrodes 130R, 130G, 130B of the thin film transistor array substrate TFT_S, and black The matrices 140 are formed corresponding to the banks 140 of the thin film transistor array substrate TFT_S.

According to the organic light emitting display device according to the embodiment of the present invention described above, the air gap (air) by the concave portion (200a) formed at the position of the second substrate 200 corresponding to the color filter layers (220R, 200G, 220B) gap) is formed, and a high-viscosity flattening film 210 is formed on the upper side thereof, and thus the red color filter layer 200R, the green color filter layer 200G, and the blue color filter layer 200B according to the difference in refractive index between the air gap and the high-viscosity material layer of the air gap ), the light efficiency is changed.

Next, the light efficiency of the organic light emitting display device according to an exemplary embodiment of the present invention will be described in detail with reference to Table 1. Table 1 is data showing luminance of light emitted through red, green, and blue color filters of the organic light emitting display device according to the comparative example and the organic light emitting display devices according to Examples 1 to 4 of the present invention. In Table 1, the comparative example is an organic light emitting display device having no high-viscosity flattening film and concave portions of the second substrate, and Examples 1 to 4 are organic light-emitting display devices having a high-viscosity flattening film and concave portions of the second substrate. 1 is a high-viscosity flat film has a refractive index of 1.2, Example 2 has a high-viscosity flat film has a refractive index of 1.3, Example 3 has a high-viscosity flat film with a refractive index of 1.3, and Example 4 has a high-viscosity flat film with a refractive index of 1.4. It is showing.

Comparative example
(cd/m ² } Example 1
(Refractive index 1.2)
(cd/m ² } Example 2
(Refractive index 1.3)
(cd/m ² } Example 3
(Refractive index 1.4)
(cd/m ² } Red color filter 25.3 25.8 27.3 27.7 Green filter filter 39.2 41.0 40.4 38.8 Blue filter filter 2.1 202 2.2 2.2

As can be seen from the above experimental results, when comparing Example 1 and Comparative Example, the light transmitted through the red color filter is improved by 2% compared to the Comparative Example 1, and the light transmitted through the green color filter. It can be seen that the first embodiment is 4.6% higher than the comparative example, and the light transmitted through the blue color filter is 4.8% higher than the comparative example. Further, when comparing Example 2 and Comparative Example, the light transmitted through the red color filter is improved by 7.9% compared to the Comparative Example, and the light transmitted through the green color filter is 3.1 compared to the Comparative Example. % Improvement, the light transmitted through the blue color filter can be seen that the second embodiment is improved by 4.8% than the comparative example. Further, when comparing Example 3 and Comparative Example, the light transmitted through the red color filter is improved by 9.5% compared to the Comparative Example 3, and the light transmitted through the green color filter is compared to the Comparative Example -3. It can be seen that the third embodiment is lowered by 1.0% and the light transmitted through the blue color filter is improved by 4.8% compared to the comparative example.

From Table 1 above, it can be seen that the overall light efficiency of the organic light emitting display device according to embodiments of the present invention is improved.

Through the above description, those skilled in the art will appreciate that various changes and modifications are possible without departing from the technical idea of the present invention. For example, in the description of the exemplary embodiment of the present invention, although the first protective film for protecting the thin film transistor and the second protective film for planarization are described separately, only one of the first protective film or the second protective film may be formed. Therefore, the technical scope of the present invention should not be limited to the contents described in the detailed description of the invention, but should be determined by the claims.

100: first substrate 110: TFT forming layer
120: reflector 130R, 130G, 130B: first electrode
140: bank 150: white OLED
160: second electrode 170: protective film
200: second substrate 200a: concave
210: high-viscosity flattening film 220: color filter layer
220R: Red color filter 220G: Green color filter
220B: Blue color filter 230: Black matrix
300: adhesive layer

Claims (7)

A thin film transistor substrate on which a white organic light emitting device is formed between a plurality of first electrodes and a second electrode respectively connected to a plurality of thin film transistors formed on the first substrate; And
And a color filter substrate disposed opposite to the thin film transistor substrate,
The color filter substrate,
A second substrate having a plurality of recesses formed at positions corresponding to the first electrodes;
A high-viscosity planarization film formed on the second substrate; And
It includes a plurality of color filter layers formed on the high-viscosity flattening film,
Each of the plurality of concave portions has an air gap positioned between the second substrate and the high-viscosity flattening film.
According to claim 1,
The high-viscosity flattening film has an refractive index in the range of 1.2 to 1.4, an organic light emitting display device.
According to claim 1,
The high-viscosity planarization film is poly[4,5-difluoro-2,2-bis(trifluoromethyl)-1,3-dioxole-cotetrafluoroethylene] (Poly[4,5-difluoro-2, 2-bis(trifluoromethyl)-1,3-dioxole-co-tetrafluoroethylene]), poly(2,2,3,3,4,4,4-heptafluorobutyl acrylate), poly(2,2,3 ,4,4,4-hexafluorobutyl acrylate), poly(2,2,2-trifluoromethyl acrylate), poly(2,2,2-trifluoromethane acrylate), poly( 1,1,1,3,3,3-hexafluorobutyl acrylate).
The method according to any one of claims 1 to 3,
The plurality of color filter layers are formed in correspondence with the concave portions of the second substrate.
The method of claim 4,
And a reflective layer formed between the thin film transistor substrate and the first electrodes.
The method of claim 5,
The plurality of first electrodes are respectively connected to the thin film transistors through contact holes formed in the reflective layer.
According to claim 1,
An organic light emitting display device characterized in that an air layer is formed in the air gap.

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