KR20200036671A - Color conversion structure and display device including the same - Google Patents

Abstract

Disclosed are a color conversion structure and a display device including the same. The color conversion structure comprises: organic fluorescent dyes converting a first light into a second light; and clumpings made of a collection of organic fluorescent dyes wherein the sizes of clumpings range from approximately 150 nm to approximately 1000 nm. The first light is a white light or a blue light and the second light is a green light or a red light. Therefore, color conversion efficiency is increased.

Description

Color conversion structure and display device including the same {COLOR CONVERSION STRUCTURE AND DISPLAY DEVICE INCLUDING THE SAME}

The present invention relates to a color conversion structure and a display device including the same.

A color filter transmits light from a light source, for example, light in a red wavelength band, light in a green wavelength band, and light in a blue wavelength band and absorbs light of other wavelengths, so that the display device is red and green. , It is an optical component that enables blue.

The color filter is generally widely used in a liquid crystal display device, but is also used for color reproduction of a white organic light emitting diode display device. Since the color filter absorbs light of a different wavelength band except light of a wavelength band of a predetermined color to be expressed, light transmittance or light efficiency may be reduced.

The color conversion structure may implement red and green by converting incident light to light in a red wavelength band and light in a green wavelength band. The color conversion structure may replace the color filter or may be used together with the color filter to compensate for the disadvantages of the color filter.

The present invention is to provide a color conversion structure and a display device including the same, which improves color conversion efficiency and ensures stability.

The problems to be solved by the invention are not limited to those mentioned above, and the problems not mentioned will be clearly understood by those skilled in the art from the following description.

The color conversion structure according to the invention comprises organic fluorescent dyes for converting the first light into the second light and a collection of the organic fluorescent dyes, and includes clumpings having a size of about 150 nm to about 1000 nm. The first light is white light or blue light, and the second light is green light or red light.

The display device according to the present invention includes a light source that emits first light, a color conversion structure disposed on the light source, and an adjacent layer disposed on the light source and directly disposed on the color conversion structure.

The color conversion structure is composed of a collection of organic fluorescent dyes that convert the first light into the second light and the organic fluorescent dyes, and includes clumpings having a size of about 150 nm to about 1000 nm. The first light is white light or blue light, and the second light is green light or red light.

The adjacent layer can include the clumpings.

Specific details of other embodiments are included in the detailed description and drawings.

The color conversion structure according to the present invention can exhibit at least the following effects.

The color conversion structure according to the present invention can improve color conversion efficiency by including scattering body-sized clumping, and can prevent or minimize a decrease in thermochemical stability due to the scatterer and a decrease in transmittance of the entire visible light region.

The effects according to the invention are not limited by the contents exemplified above, and more various effects are included in the present specification.

1 is a schematic diagram of a display device according to an embodiment of the invention.
FIG. 2 is a schematic diagram of the clumping contained in the red converting part and the green converting part of FIG. 1, (a) shows the clumping contained in the green converting part, and (b) the clump contained in the red converting part. Shows rumping.
3 schematically shows the surface of the red conversion unit.
4 is an image of light emission of a color conversion structure including clumping.
5 is an image of a color conversion structure including clumping.
Figure 6 is an image showing the structure of the color material aggregated
7 is a graph showing a change in color conversion efficiency according to a change in size of clumping.
8 schematically shows a red cross-section side sectional view.
9 schematically shows the structure of the interface between the red conversion unit and the adjacent layer.
10 is an image of light emission (emission) showing the case where the clumping is diffused to the adjacent layer.
11 is a schematic diagram of a display device according to another embodiment of the present invention.

Advantages and features of the invention, and methods for achieving them will be made clear by referring to embodiments and experimental examples described below in detail together with the accompanying drawings. It should be noted that the accompanying drawings are only for facilitating understanding of the spirit of the technology disclosed in this specification, and should not be interpreted as limiting the spirit of the technology by the accompanying drawings.

In addition, the invention is not limited to the contents disclosed below, but may be implemented in various forms, and the contents disclosed below allow the disclosure of the invention to be complete, and to those skilled in the art to which the invention pertains It is provided to fully inform the scope of and the invention is only defined by the scope of the claims.

If it is determined that the detailed description of the related known technology may obscure the gist of the technology, the detailed description may be omitted.

Although the first, second, etc. are used to describe various components, it goes without saying that these components are not limited by these terms. These terms are only used to distinguish one component from other components, and it is needless to say that the first component may be the second component, unless otherwise stated.

Throughout the specification, unless otherwise specified, each component may be singular or plural.

Throughout the specification, when a part is referred to as "including" or "having" a component, it does not exclude other components unless specifically stated to the contrary. It means what can be included.

Throughout the specification, when referring to “A and / or B”, this means A, B or A and B unless specifically stated to the contrary, when referring to “C to D”, this refers to Unless otherwise, it means that it is C or more and D or less.

Elements or layers referred to as "on" or "on" of another device or layer are not only directly above the other device or layer, but also when intervening another layer or other device in the middle. All inclusive. On the other hand, when a device is referred to as “directly on” or “directly above”, it indicates that no other device or layer is interposed therebetween.

The spatially relative terms “below”, “beneath”, “lower”, “above”, “upper”, etc., are as shown in the figure. It can be used to easily describe the correlation of a device or components with other devices or components. The spatially relative terms should be understood as terms including different directions of the device in use or operation in addition to the directions shown in the drawings.

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

1 is a schematic diagram of a display device 100 according to an embodiment of the invention. 2 is a schematic diagram of the clumpings (GC, RC) contained in the red converting unit (R-CCM) and the green converting unit (G-CCM) of FIG. 1, (a) is a green converting unit (G-CCM) ) Shows the clumpings (GC), and (b) shows the clumpings (RC) contained in the red converter (R-CCM).

The display device 100 includes a light source LS emitting the first light L and color conversion structures R-CCM and G-CCM disposed on the light source LS. For example, the display device 100 may be a liquid crystal display device or an organic light emitting display device. For example, the light source LS may be a backlight unit or an organic light emitting device.

The light source LS may emit white light or blue light. Therefore, the first light L may be white light or blue light.

The color conversion structures R-CCM and G-CCM convert the first light L into the second light G and R. The color conversion structure (R-CCM, G-CCM) may include a green conversion unit (G-CCM) and a red conversion unit (R-CCM), and the green conversion unit (G-CCM) may include a first light. (L) may be converted into green light (G), and the red conversion unit (R-CCM) may convert the first light (L) into red light (R). When the green converter G-CCM emits green light G, the display apparatus 100 may implement green. When the red converting unit R-CCM emits red light R, the display apparatus 100 may implement red.

The green converting unit (G-CCM) and the red converting unit (R-CCM) include clampings (GC, RC). The clumping contained in the green converter (G-CCM) may be referred to as green clumping (GC), and the clumping contained in the red converter (R-CCM) may be referred to as red clumping (RC). can do.

Green clumping (GC) is a collection of organic fluorescent dyes that convert light incident on the green converter (G-CCM) to green light (G), and red clumping (RC) is a red converter (R-CCM). It is a collection of organic fluorescent dyes that convert the light incident on the red light (R).

Clumpings (GC, RC) are made of organic fluorescent dyes through an organic synthesis method, and are distinguished from aggregation or aggregation of color materials. In general, aggregation or agglomeration of color materials is not preferable because it causes problems such as a decrease in optical contrast and a decrease in processability. The aggregation or agglomeration of the color material is a disadvantage to be improved. Since agglomeration or aggregation of color materials occurs naturally, it is difficult to artificially control its size, shape, density, and the like.

On the other hand, the clumpings (GC, RC) are artificially aggregated of organic fluorescent dyes through organic synthesis, and their size, shape, and density can be artificially controlled according to organic synthesis conditions. For example, the clumpings (GC, RC) form a color conversion structure (R-CCM, G-CCM) using a poly (meth) acrylic acid-based resin substituted with an organic fluorescent dye, and then the color conversion structure ( R-CCM, G-CCM) can be obtained by heating to induce thermal deformation.

The clampings GC and RC may be designed as any one of a circular shape, an elliptical shape, a polygonal shape, and a linear shape. The red converting unit R-CCM may include at least one red clumping RC of a circular shape, an elliptical shape, a polygonal shape, and a linear shape, respectively. The green converting unit (G-CCM) may include at least one green clumping (GC) of a circular shape, an elliptical shape, a polygonal shape, and a linear shape, respectively.

3 schematically shows the surface of the red conversion unit (R-CCM). Referring to FIG. 3, the red conversion unit R-CCM may include both red clumping 1RC of a circular shape and red clumping 2RC of a linear shape. The linear shape of the red clumping (2RC) may be designed to be arranged to be spaced apart from each other, the separation distance may be changed according to the wavelength of the first light (L in Figure 1). For example, in the case of blue light, the separation distance between the red clampings 2RC of the linear shape may be more than 100 nm.

Although not shown, like the red conversion unit R-CCM of FIG. 3, the green conversion unit G-CCM may also include green clumping of a circular shape and green clumping of a linear shape.

4 is an image of light emission of a color conversion structure including clumping. Figure 4 shows that the size, shape, density, etc. of the clumping can be variously changed according to the organic synthesis conditions of the organic fluorescent dyes, the area where the clumping is present (the light emitting area) and the area where the clumping is not present It shows the difference of (arm part).

FIG. 4 (a) is a light emission image of a color conversion structure having a combination of clumping of a linear shape and clumping of a circular shape. Referring to (a) of FIG. 4, the color conversion structure may be formed in a structure in which the clumping of a circular shape and the clumping of a linear shape are combined, and the clumping of circular shapes of different sizes may be formed in a complex structure. Can be. . FIG. 4 (b) is a light emission image of a color conversion structure composed of clumping of a circular shape. Referring to (b) of FIG. 4, the color conversion structure is composed of various types of clumping such as triangular shaped clumping, star shaped clumping, polygonal shaped clumping, circular shaped clumping, and the like. Structure can be formed. Fig. 4 (c) shows the light emission image of the color conversion structure composed of the clumping of the linear shape. Referring to (c) of FIG. 4, the color conversion structure may be formed in a structure in which the clampings of linear shapes are spaced apart from each other. As shown in (a), (c) and (c) of FIG. 4, the clumping can be controlled in shape and size.

The color conversion structure (R-CCM) has a surface on which protrusions made of clampings (1RC or 2RC) protrude. The protrusions made of the clampings 1RC or 2RC are formed at a uniform height compared to the protrusions made of aggregates of color materials. The projections made of the clumpings (1RC or 2RC) had smaller values of roughness parameters (Rp, Rv, Rz, Rsk, Rku) than those made of aggregates of color materials.

The surface roughness parameters (Rp, Rv, Rz, Rsk, Rku) of the color conversion structure (R-CCM) per unit area are as follows. The maximum mountain height (Rp) of the protrusions made of clumpings (1RC or 2RC) may be in the range of 0.6 μm to 0.8 μm, and the maximum bone depth (Rv) of the protrusions made of clumpings (1RC or 2RC) is 0.4 It may be in the range of µm to 0.6 µm, and the maximum height roughness (Rz) of the protrusions made of clampings (1RC or 2RC) may be in the range of 1.0 µm to 1.5µm, and made of clampings (1RC or 2RC) The skewness (Rsk) of the roughness profile of the protrusions may be in the range of 1.6 to 2.0, and the kurtosis (Rku) of the roughness of the protrusions consisting of the clampings (1RC or 2RC) may be in the range of 5.0 to 7.0.

The maximum mountain height (Rp) of the protrusions made of agglomerates of color materials is 1.0 μm or less, and the maximum bone depth (Rv) of the protrusions made of agglomerates of color materials is in the range of 0.8 μm to 1.0 μm, and the protrusions made of aggregates of color materials The maximum height roughness (Rz) is in the range of 1.5 µm to 2.0 µm, and the skewness (Rsk) of the roughness profile of the projections made of agglomerates of colorants is in the range of 4.0 to 6.0, of the roughness of the projections made of agglomerates of colorants The kurtosis (Rku) is in the range of 35.0 to 130.0.

5 shows an image of a color conversion structure (R-CCM or G-CCM) including clumping (RC or GC), and FIG. 6 shows an image of a structure in which color materials are aggregated. Clumpings composed of a collection of organic fluorescent dyes (RC or GC) are evenly distributed within a unit area of the color conversion structure (R-CCM or G-CCM) (FIG. 5). On the other hand, the structure in which the color materials are aggregated has an uneven distribution within the unit area (Fig. 6). Table 1 below summarizes the measurement results of surface roughness values in the unit area of FIGS. 5 and 6.

Clumping (Figure 5) Aggregate of color materials (Fig. 6) Rp (maximum mountain height) 0.871㎛ 0.965㎛ Rv (maximum goal depth) 0.584㎛ 0.814㎛ Rz (sum of Rp and Rv) 1.455㎛ 1.779㎛ Rsk (skewness of roughness profile) 1.6203 4.6101 Rku (Kurtosis of roughness) 5.7634 35.6949

The size of the clumpings (RC or GC) may be in the range of approximately 150 nm to approximately 1000 nm. The size of the clumpings RC or GC may be changed according to the wavelength of the first light (L in FIG. 1) within the above range. For example, in the case of blue light, the sizes of the clumpings (RC or GC) may be approximately 150 nm to approximately 600 nm.

7 is a graph showing a change in light emission efficiency according to a change in size of the clampings RC or GC. Referring to FIG. 7, when the size of the clumpings (RC or GC) is about 150 nm to about 1000 nm, the size of the clumpings (RC or GC) is less than about 150 nm and the clumpings (RC or GC) Compared to the case where the size of GC) is greater than approximately 1000 nm, light emission efficiency is excellent.

FIG. 8 schematically shows a cross-sectional side view of the red conversion unit (R-CCM), and FIG. 9 schematically shows the structure of an interface between the red conversion unit (R-CCM) and adjacent layers Ly1 and Ly2. . The red conversion unit (R-CCM) has a surface including protrusions composed of red clumping (RC), and referring to FIG. 9, the red clumping (RC) is a triangular shape, a star shape, a polygonal shape, etc. It can be formed as. On the other hand, adjacent layers (Ly1, Ly2) disposed directly on the red conversion unit (R-CCM) have a surface where the interface with the red conversion unit (R-CCM) meshes with the surface of the red conversion unit (R-CCM). You can.

The clumpings (see RC) may be diffused into adjacent layers Ly1 and Ly2, and the adjacent layers Ly1 and Ly2 may include red clumpings RC. 10 is an image of light emission (emission) showing the case where the clumping is diffused to the adjacent layer. Referring to FIG. 10, red clumping (dashed circles) diffused into adjacent layers (see Ly1 and Ly2 in FIG. 9) is larger and brighter than red clumping protruding on the surface of the red conversion part (R-CCM). Lose.

Although not shown, the adjacent layer disposed directly on the green converter (G-CCM), similar to the red converter (R-CCM) of FIGS. 8 and 9, has a green interface with the green converter (G-CCM). It may have a surface engaging with the surface of the negative (G-CCM). Further, although not shown, as in FIG. 10, green clumpings may be diffused into the adjacent layer, and the adjacent layer may include green clumping.

11 is a schematic diagram of a display device 1000 according to another embodiment of the present invention.

The display device 1000 includes a display area in which each pixel is arranged in a matrix form and a non-display area disposed around the display area, and the display area allows a viewer to view an image or information generated by the display device 1000. This is an area that can be viewed, and the non-display area is an area in which viewers cannot view images or information generated by the display device 1000, and is also commonly referred to as a bezel area. The display apparatus 1000 includes a plurality of pixels, and FIG. 11 illustrates one pixel among a plurality of pixels provided in the display apparatus 1000.

The pixel may be divided into sub-pixels, and the sub-pixel may be divided into a first sub-pixel, a second sub-pixel, and a third sub-pixel. For example, the first sub-pixel may include a red pixel unit (RE), The second sub-pixel may be a green pixel portion GE and the third sub-pixel may be a blue pixel portion BE.

Thin film transistors 210 are formed on the lower substrate 111. Each of the thin film transistors 210 includes a semiconductor layer 211, a gate electrode 212, a source electrode 215 and a drain electrode 214. In FIG. 11, the thin film transistors 210 are formed by an upper gate (top gate) method in which the gate electrode 212 is positioned on the semiconductor layer 211, but is not limited thereto. That is, in the thin film transistors 210, a lower gate (bottom gate, bottom gate) method in which the gate electrode 212 is positioned under the semiconductor layer 211 or the gate electrode 212 has upper and lower portions of the semiconductor layer 211. It may be formed in a double gate (double gate) method that is located in all.

Semiconductor layers 211 are formed on the lower substrate 111. A buffer film (not shown) may be formed between the lower substrate 111 and the semiconductor layers 211 to protect the semiconductor layers 211 and increase the interfacial adhesion of the semiconductor layers 211. The buffer film (not shown) may include a plurality of inorganic films. An interlayer insulating layer 220 may be formed on the semiconductor layers 211. Gate electrodes 212 may be formed on the interlayer insulating layer 220.

A gate insulating layer 230 may be formed on the gate electrodes 212. Source electrodes 215 and drain electrodes 214 may be formed on the gate insulating layer 230. Each of the source electrode 215 and the drain electrode 214 may be connected to the semiconductor layer 211 through a contact hole passing through the interlayer insulating layer 220 and the gate insulating layer 230.

A planarization layer 240 may be formed on the source electrodes 215 and the drain electrodes 214. The planarization layer 240 is a layer for flatly arranging pixels partitioned by the banks 255. The planarization layer 240 may be formed of a resin such as photo acryl and polyimide.

Organic light emitting devices are formed on the planarization layer 240. Each of the organic light emitting elements includes an anode electrode 251, an organic layer 253, and a cathode electrode 254, and is divided by a bank 255.

Anode electrodes 251 are formed on the planarization layer 240. Each of the anode electrodes 251 is connected to the drain electrode 214 through a contact hole passing through the planarization layer 240. The bank 255 partitions the anode electrodes 251. The bank 255 is formed to cover each edge of the anode electrodes 251.

The organic layer 253 is formed on the anode electrodes 251 and the banks 255. The organic layer 253 may include a hole transporting layer, a light emitting layer, and an electron transporting layer. In this case, when a voltage is applied to the anode electrode 251 and the cathode electrode 254, holes and electrons move to the light emitting layer through the hole transport layer and the electron transport layer, respectively, and the light emitting layers combine to emit light.

The emission layer includes a red light emitting unit emitting light in a red wavelength band, a green light emitting unit emitting light in a green wavelength band, and a blue light emitting unit emitting light in a blue wavelength band, and may emit white light. The red light emitting part may be formed only on the red pixel parts RE, the green light emitting part may be formed only on the green pixel parts GE, and the blue light emitting part may be formed only on the blue pixel parts BE.

The cathode electrode 254 is formed on the organic layers 253 and the banks 255 to cover the organic layers 253 and the banks 255.

The display device 1000 may be implemented in a top emission method. In the upper emission method, since the light emitted from the organic layer 253 emits light toward the upper substrate 112, the thin film transistors 210 may be widely provided under the bank 255 and the anode electrode 251. That is, the upper emission method has an advantage that the design area of the thin film transistors 210 is wider than that of the lower emission method.

In addition, in the top emission method, it is preferable that the anode electrodes 251 are formed of aluminum and a metal material having high reflectivity such as a stacked structure of aluminum and ITO to obtain a micro cavity effect. Further, in the upper emission method, since the light emitted from the organic layer 253 emits light toward the upper substrate 112, the cathode electrode 150 is formed of a transparent metal material such as ITO or IZO that can transmit light, Alternatively, it may be formed of a translucent metal material such as magnesium (Mg), silver (Ag), or magnesium (Mg) and silver (Ag).

An encapsulation film 260 is formed on the cathode electrode 254. The encapsulation layer 260 serves to prevent oxygen or moisture from penetrating the organic layer 253. To this end, the encapsulation film 260 may include a first inorganic material film 261, an organic material film 262, and a second inorganic material film 263.

The first inorganic material film 261 is formed on the cathode electrode 254 to cover the cathode electrode 254. The organic material film 262 is a first inorganic material film 261 to prevent foreign particles from entering the organic material film 253 and the cathode electrode 254 through the first inorganic material film 261. It is formed on. The second inorganic material film 263 is formed on the organic material film 262 to cover the organic material film 262.

Each of the first and second inorganic material films 261 and 263 may be formed of silicon nitride, aluminum nitride, zirconium nitride, titanium nitride, hafnium nitride, tantalum nitride, silicon oxide, aluminum oxide, or titanium oxide. For example, each of the first and second inorganic material films 261 and 263 may be formed of SiO2, Al2O3, SiON, or SiNx. The organic material film 262 may be formed transparently to pass light emitted from the organic film 253.

The color filter layer 310, color conversion units R-CCM, G-CCM, and black matrix BM may be disposed on the upper substrate 112. The black matrices BM may divide the color layer for each pixel unit. The color layer includes a color filter layer 310 and color conversion units (R-CCM, G-CCM).

The color filter layer 310 includes a red filter unit 311, a green filter unit 312, and a blue filter unit 313. The red filter unit 311 is disposed on the red light emitting unit in the red pixel unit RE. The green filter unit 312 is disposed on the green light emitting unit in the green pixel unit GE. The blue filter unit 313 is disposed on the blue light emitting unit in the blue pixel unit BE.

The red conversion unit R-CCM is disposed between the red filter unit 311 and the encapsulation layer 260 on the red light emission unit of the red pixel unit RE, and the green conversion unit G-CCM is a green pixel unit. On the green light emitting part of (GE), it is disposed between the green filter part 312 and the sealing film 260.

 The display device 1000 is a white organic light emitting display device that emits white light. Referring to FIGS. 9 and 11, the adjacent layer Ly1 may be an encapsulation film 260, and the adjacent layer Ly2 may be colored. It may be a filter layer 310.

On the other hand, although not shown, when the light emitting layer of the organic layer 253 emits blue light, color conversion units (R-CCM, G-CCM) and a black matrix (BM) may be disposed on the upper substrate 112. And the color filter layer 310 may be omitted. In this case, the adjacent layer Ly1 of FIG. 9 may be the encapsulation film 260, and the adjacent layer Ly2 of FIG. 9 may be the upper substrate 112.

In order to improve the color conversion efficiency or the wavelength conversion efficiency of the color conversion units that convert the wavelength of the incident light into red light or green light, a scattering body may be added to the color conversion units, but the scattering body may improve the thermochemical stability of the color conversion units. It is damaged, and there is a problem of lowering the transmittance in the entire visible light region.

The color conversion structures (R-CCM, G-CCM) can solve the above-mentioned problems, and specifically, the color conversion structures (R-CC, G-CCM) are used for scattering body-size clamping (RC, GC). By including, it is possible to improve the color conversion efficiency of the color conversion structure (R-CCM, G-CCM), it is possible to prevent or minimize the reduction of the thermochemical stability due to the scattering body and the decrease in transmittance of the entire visible light region.

The clumpings (RC, GC) can be controlled in accordance with the organic synthesis conditions, such as shape and density, so that they can be uniformly present in the color conversion structures (R-CCM, G-CCM) with uniform size and shape. Color conversion efficiency or wavelength conversion efficiency of the conversion structures (R-CCM, G-CCM) may be improved, and light extraction efficiency of the display devices 100 and 1000 may be increased.

Although the embodiments have been described with reference to the accompanying drawings, the invention is not limited to the above embodiments, and may be manufactured in various different forms by combining the contents disclosed in each embodiment, and it is common in the art to which the invention pertains. Those skilled in the art will appreciate that the invention can be implemented in other specific forms without changing the technical spirit or essential features of the invention. Therefore, it should be understood that the embodiments described above are illustrative in all respects and not restrictive.

Claims (6)

Organic fluorescent dyes that convert the first light into the second light; And
Consists of a collection of the organic fluorescent dyes, and includes clumpings having a size of 150 nm to 1000 nm,
The first light is white light or blue light,
The second light is red light or green light
Color conversion structure. According to claim 1,
A color conversion structure having a surface including protrusions formed of the clumping. According to claim 1,
The clumping is at least one of a circular shape, an elliptical shape, a polygonal shape, and a linear shape.
Color conversion structure. A light source emitting a first light;
A color conversion structure disposed on the light source; And
It is disposed on the light source, the adjacent layer disposed directly on the color conversion structure; includes,
The color conversion structure
Consists of a collection of organic fluorescent dyes for converting the first light to the second light, the organic fluorescent dyes, and includes clumpings having a size of 150 nm to 1000 nm,
The first light is white light or blue light,
The second light is red light or green light
Display device. According to claim 4,
The color conversion structure has a surface including protrusions composed of the clumping,
The adjacent layer has an interface with the color conversion structure complementary to the surface.
Display device. According to claim 4,
The adjacent layer includes the clumping
Display device.

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