KR100745343B1 - Green color filter and organic light-emitting display device - Google Patents

Abstract

The present invention relates to a green color filter for implementing mixed light generated from blue and red light sources into green light having improved luminous efficiency and color coordinates, and an organic light emitting display device using the same. The green color filter according to the present invention comprises a color conversion member for converting the blue wavelength light emitted from the light emitting sources emitting blue and red wavelength light into the green wavelength light, and the red blocking member for blocking the red wavelength light. It is characterized by including.

Color filter, organic light emitting display, green color conversion material, light emitting source, red blocking

Description

Green color filter and organic light-emitting display device using the same

1 is a schematic diagram of a green color filter according to the prior art.

Figure 2 is a schematic diagram showing an embodiment of a green color filter according to the present invention.

Figure 3 is a graph showing the emission spectrum of the light emitting source used in the green color filter according to the present invention.

Figure 4 is a graph showing the emission spectrum of the color conversion member of the green color filter according to the embodiment of FIG.

5 is a graph showing the transmittance of the red blocking member of the green color filter according to the embodiment of FIG.

6 is a cross-sectional view illustrating an embodiment of an organic light emitting display device to which a green color filter according to the present invention is applied.

7 is a cross-sectional view illustrating another embodiment of an organic light emitting display device to which a green color filter according to the present invention is applied.

8 is a graph showing an emission spectrum of an organic light emitting display device according to an exemplary embodiment of the present invention in which a green color filter is formed in a blue and green light emitting layers.

FIG. 9 is a graph showing emission spectra of organic light emitting display market values in which a conventional green color filter is formed on blue and green light emitting layers. FIG.

10 is a color coordinate graph showing an improved color coordinate of an organic light emitting display according to the present invention.

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

110 and 210: first electrode 120 and 220: organic light emitting layer

130, 230: second electrode 160, 260: color filter substrate

161, 261: red color filter 162, 262: green color filter

162a, 262a: color conversion member 162b, 262b: red blocking member

163, 263: blue color filter

The present invention relates to a green color filter and a flat panel display device using the same, and more particularly, to a green color filter and an organic light emitting display device using the same, which implements color light with improved luminous efficiency and color coordinates from mixed light of blue and red light. .

As a method of implementing full color in a flat panel display device, especially an organic light emitting device, three-color light emission, color filter, and color conversion are known. The tricolor emission method is a method of emitting light of three colors of R, G, and B respectively, and the color filter method is a method of dividing light from a white light source into R, G, and B through color filters. The conversion method is a method of dividing light emitted from a blue light source into R, G, and B using a color conversion material (phosphor) instead of a color filter.

The tri-color emission method has a problem in that the lifetime of one color determines the overall lifetime, and the color filter method has a problem in that white light is absorbed by the color filter and the amount of light falls, and the color conversion method is excited by the color conversion material by blue light. There is a problem that is lowered, has been studied how to implement a full color, longer life, excellent luminous efficiency and color coordinates. In particular, many improvements have been made to the color filter and color conversion method, which is composed of a shadow maskless process and can achieve high definition.

For example, US Patent No. 6515418 discloses an organic light emitting device using a light emitting layer for emitting white light and a color filter formed using photolithography. However, such a color filter has a problem in that luminous efficiency should be reduced to improve color purity of each of R, G, and B.

1 is a schematic view of a color light emitting device including a conventional green color filter disclosed in Korean Patent Publication No. 10-2004-00058293. The color light emitting device converts blue light into green light from white light and transmits only green light. A color light emitting device including a green color filter is disclosed, but there is a problem of using a wavelength of red, green, and blue that has a change in color coordinates and a complicated manufacturing process as a tricolor light emitting source. In order to solve this problem, a green color filter using a light source having two wavelengths has been studied.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and the present invention provides a green color filter including a color conversion member and a red blocking member using a mixed light of blue and red light as a light emitting source, and an organic light emitting display device using the same. It aims to provide.

The green color filter according to the present invention is a color conversion member for converting the light of the blue wavelength emitted from the light emitting sources emitting blue and red wavelengths to the light of the green wavelength, and the red blocking member for blocking only the light of the red wavelength It is characterized by including.

In addition, the organic light emitting display device according to the present invention includes a substrate, a first electrode formed on one surface of the substrate, an organic light emitting layer for emitting a mixed light of blue and red wavelengths formed on the first electrode, formed on the organic light emitting layer And a second color electrode and a green color filter formed in the green pixel region of the other surface of the substrate, wherein the green color filter converts light of blue wavelength emitted from the organic light emitting layer into light of green wavelength and red wavelength. And a red blocking member that blocks the light of the red wavelength.

In addition, the organic light emitting display device according to the present invention includes a substrate, a first electrode formed on one surface of the substrate, an organic light emitting layer for emitting mixed light of blue and red wavelengths formed on the first electrode, and formed on the organic light emitting layer. And a second color electrode and a green color filter formed on an outer side of the second electrode, wherein the green color filter includes a color conversion member for converting blue wavelength light emitted from the organic light emitting layer into a green wavelength; It characterized in that it comprises a red blocking member for blocking the light of the red wavelength.

Hereinafter, a preferred embodiment of the green color filter according to the present invention will be described in more detail with reference to FIG. 2 is a block diagram of a green color filter according to an embodiment of the present invention. Accordingly, the green color filter includes a color conversion member and a red blocking member, and the light emitting source used is a mixture of blue light and red light, so that the color coordinates are white light having X = 0.20 to 0.50 and Y = 0.20 to 0.43. .

3 shows light emission spectra of the light source used in the present color filter. As such, when the light emitting source is composed of only blue light and red light, there is an advantage in that the color coordinate of the light emitting source is not severely changed according to the driving voltage and the current density, and the light emitting source can be easily manufactured.

The color conversion member is composed of a material for converting blue light emitted from the light emitting source into green light. A graph showing the emission spectrum of the light transmitted through the color conversion member is shown in FIG. 4. According to this, the wavelength of the emitted green light is 450 nm to 630 nm, most of which is in the green region wavelength, and the red region wavelength of 610 to 630 nm is slightly reduced. It can be seen that it is included.

In this case, the color conversion material may be composed of only fluorescent dyes and binder resins or fluorescent dyes. For example, fluorescent dyes include 3- (2'-banzothiazolyl) -7-diethylaminocoumarin (hereafter coumarin 6), 3- (2'-benzimidazolyl) -7-N, N-diethylamino Coumarins (hereafter coumarin 7), Alq3 or fluorescent inorganic and organic pigments can be used.

A red blocking member is formed in contact with the first color conversion member, and a pigment or a pigment thereof, which is configured to have a transmittance of 30% or less between 550 nm and 750 nm and a transmittance of 60% or more between 400 nm and 530 nm, is dissolved in a binder resin. Or a dispersed material. At this time, since the red blocking member is composed of only a pigment that blocks only red color, the red blocking member is more easily manufactured. On the other hand, Figure 5 is a graph showing the transmission spectrum of the red blocking member.

On the other hand, the green color filter may be configured such that the color conversion member and the red blocking member are formed in two different layers, respectively, and the color conversion member and the red blocking member are mixed with each other to form one mixed layer.

When passing through the green color filter described above, the blue light is converted into green light and red light by the color conversion member, and the red light emitted from the red light and the light source is removed by the red blocking member so that only the green light remains.

Hereinafter, the flat panel display using the green color filter will be described in detail by applying the aforementioned green color filter to the organic light emitting display device which is one of the flat panel display devices. However, those skilled in the art will recognize that the green color filter may be applied to various display devices such as liquid crystal display devices in addition to the organic light emitting display device.

6 is a cross-sectional view illustrating an embodiment of an organic light emitting display device to which a green color filter according to the present invention is applied. Accordingly, the organic light emitting display device includes a green color filter 163 formed on the substrate 100, the first electrode 110, the organic light emitting layer 120, the second electrode 130, and the transparent substrate 170. It is configured by.

The substrate 100 may be a glass or transparent plastic substrate having excellent transparency, surface smoothness, ease of handling, and waterproofness.

Since the first electrode 110 and the second electrode 130 can be used in the present invention without limiting the conventional electrode, a detailed description thereof will be omitted. However, when the electrode is an anode electrode, indium tin oxide (ITO), indium zinc oxide (IZO), tin oxide (SnO 2), zinc oxide (ZnO) may be used as a member, and in the case of the cathode electrode, lithium, magnesium, Aluminum, aluminum-lithium, calcium, magnesium-indium, magnesium-silver and the like can be used.

The organic light emitting layer 120 is configured to emit a mixture of blue and red light, in which the organic light emitting layer essentially comprises a light emitting layer, a hole injection layer, a hole transport layer, a light emitting layer, a hole blocking layer, an electron injection layer, an electron transport layer It is used as a concept to selectively include and the like. Matters related to the members, functions, and the like for each layer are well known to those skilled in the art, and thus detailed description thereof will be omitted.

The organic light emitting layer for emitting the mixed light may be configured in various ways. For example, the blue and red light emitting layers may be formed respectively, or the light emitting layers may be divided into a plurality of light emitting members having blue and red wavelengths.

Materials for blue light emission include Firpic, (3,5-diCF3ppy) Irpic, (3-CNppy) Irpic, (3,5-diCNppy) Irpic, SDI-BD-785, SDI-BD-735, SBD02 One selected from the group may be used, and a material selected from the group consisting of (btp) 2Ir (acac), pq3Ir, pq2Ir (acac), DCM2, DCJTB may be used as a material for red light emission.

The control of the luminous intensity can be efficiently controlled by mixing the above materials in an appropriate ratio, and adjusting the thickness of the light emitting layer, the ratio of the host and the dopant of the light emitting layer. In this case, it is preferable that the mixed light has a color coordinate of X = 0.20 to 0.50 and Y = 0.20 to 0.43.

The green color filter 163 is formed in the green pixel region of the transparent substrate 170 which is in contact with the other surface of the substrate, and the blue color filter 164 and the red color filter 162 are also provided on the transparent substrate. The transparent substrate is coated with a black matrix 161 is patterned.

The green color filter 163 includes a color conversion member 163a and a red blocking member 163b. The color conversion member 163a is composed of a member for converting the blue light emitted from the light emitting source into the light of the green wavelength and the light of the small red wavelength, and the wavelength of the converted light is 450 nm to 630 nm, as described above, and the green color of 450 nm to 610 nm. And red regions in the low range of 610-630 nm.

The color conversion member 163a may be composed of only fluorescent dyes, binder resins or fluorescent dyes. For example, 3- (2'-Vanthiathiazolyl) -7-diethylaminocoumarin (hereafter coumarin 6), 3- (2'-benzimidazolyl) -7-N, N-diethylaminocoumarin (hereafter , Coumarin 7) or fluorescent inorganic and organic pigments may be used.

The color conversion member 163a may be formed by forming a color conversion resin composition on a substrate to a desired thickness. In this case, as the film forming method used, a spin coating method, a printing method, a coating method, or the like may be used, and a transfer method may also be used. It is preferable that the film-forming thickness shall be 1-30 micrometers. This is because the color conversion is not smooth in the case of 1 μm or less, and in lithography in the case of 30 μm or more.

The red blocking member 163b is formed in contact with the color conversion member 163a, and has a pigment or a pigment thereof that has a transmittance of 30% or less between 550 nm and 750 nm and a transmittance of 60% or more between 400 nm and 530 nm. It consists of the material melt | dissolved or disperse | distributed to binder resin. At this time, since the red blocking member 163b is composed of only a pigment that blocks only red color, the manufacturing of the red blocking member 163b becomes easier.

The red blocking member 163b may be formed by forming a film to have a desired thickness on the color conversion member 163a. In this case, spin coating, roll coating, bar coating, casting, and transfer methods may be used as the film forming method. Lithography and screen printing may be used for patterning after film formation. At this time, the red blocking member 163b may be formed to 0.5 to 5㎛. This is because it is difficult to control the transmittance below 0.5 μm, and there is a difficulty in lithography above 5 μm. Preferably it is 1-2 micrometers.

When passing through the green color filter described above, the blue light is converted into green light and red light by the color conversion member 163a, and the red light emitted from the red light and the light source is removed by the red blocking member so that only the green light remains.

Meanwhile, for convenience of description, in the present embodiment, additional components constituting the organic light emitting display device, for example, functions of the buffer layer 150, the black matrix 161, the transparent substrate 165, and the like are known, and various modifications thereof are known. Since the detailed description thereof is omitted, those skilled in the art will be able to easily recognize the same.

Unlike the present embodiment, as described above, the green color filter may be formed of one layer in which the color conversion material and the red blocking material are mixed. At this time, it is preferable that the film-forming thickness of a mixed layer shall be 1-30 micrometers. This is because the color conversion is not smooth in the case of 1 μm or less, and in lithography in the case of 30 μm or more.

7 is a cross-sectional view illustrating another embodiment of an organic light emitting display device to which a green color filter according to the present invention is applied. Accordingly, the organic light emitting display device includes a substrate 200, a first electrode 210, an organic light emitting layer 220, a second electrode 230, and a green color filter 263.

In the present embodiment, the green color filter 263 is not formed on the substrate 200 side, but is formed on the second electrode 230 side. At this time, the organic light emitting display device can be manufactured by bonding the color filter substrate including the green color filter to the surface of the substrate on which the organic light emitting element is formed. At this time, those skilled in the art will recognize that additional layers, such as planarization layers, may be formed on the color substrate to facilitate bonding.

This embodiment shows that the green color filter according to the present invention can be applied to both the back light emission and the top light emission, and also does not exclude the application to the double-sided light emission structure.

Hereinafter, with reference to Figure 6 describes a manufacturing method according to an embodiment of the green color filter according to the present invention comprising a color conversion member and a red blocking member as an independent layer to increase the feasibility of the present invention, The effect of the green color filter according to the invention is compared with a conventional green color filter coated with only a green color filter pigment without a color conversion member.

First, the black matrix 161 is coated on the transparent substrate 165, and then a black matrix 161 pattern is formed according to the position where the color filter of each color is coated. In accordance with the pattern, 25 mg of coumarin 6 ( 25 mg) and 2.5 g of polyvinylbutyral (PVB) were dissolved in 7.5 g of ethyl cellusolve, and the color conversion member 162a was coated within 10 μm, dried at 80 ° C. for 30 minutes, and dried. After coating the red blocking member (163b) on the upper portion and dried for 2 minutes at 80 ℃ to form a green color filter.

On the other hand, Figure 8 is a graph showing the emission spectrum of the light transmitted through the green color filter according to the present invention by emitting light from the blue and red light source, Figure 9 is a green color according to a conventional manufacturing method from the same light source as in FIG. It is a graph showing the emission spectrum of the light passing through the filter. When comparing FIG. 8 with FIG. 9, it can be seen that the green color filter according to the present invention has a higher green wavelength of light than a conventional green color filter.

On the other hand, Table 1 contrasts the color coordinates and luminous efficiency of the green color filters manufactured according to the above-described manufacturing method and the conventional green color filter when the blue and red mixed light sources having color coordinates of (0.32, 0.41) are used. .

Light source Example Comparative example Color coordinates (0.32,0.41) (0.22, 0.67) (0.27, 0.56) Luminous Efficiency (cd / A) 11.7 6.5 5.4

Accordingly, it can be seen that the color coordinates of the green color filter according to the present invention are (0.22, 0.67), so that the red light emission can be improved compared to the color coordinates (0.27, 0.56) of the general green color filter. In addition, it can be seen that the luminous efficiency is also improved to 6.5 cd / A compared to the case of applying a general green color filter.

10 is a graph showing the green color coordinates after the light emitted from the light source of the color coordinates of Table 1 passes through the green color filter, and it can be seen that the color coordinates of the green color filters are improved compared with the conventional green color filter. have.

On the other hand, Table 2 shows the results of experiments of the luminous efficiency and color coordinates of the green light passing through the green color filter when the mixed light of blue and red is different from that of Table 1.

Light source Green light after transmitting green color filter Luminous Efficiency (cd / A) 19 9.5 Color coordinates (0.34, 0.38) (0.25, 0.65)

Although the present invention has been described primarily with reference to the above embodiments, those skilled in the art will recognize that many other possible modifications and variations can be made without departing from the spirit and scope of the invention. For example, a change in the material constituting the organic light emitting layer, a change in the member and the thickness of the color conversion member or the red blocking member, etc. may be easily changed by those skilled in the art.

The green color filter and the organic light emitting display device using the same according to the present invention have an effect of efficiently increasing the characteristics of green light from blue and red mixed light.

In addition, the organic light emitting display device according to the present invention has an effect that the light emitting source is composed of only red and blue, so that the light emitting layer can be easily formed, and the change in color coordinates according to the driving voltage and the current density is not severe.

The scope of the above-described invention is defined in the following claims, and is not bound by the description in the text of the specification, all modifications and variations belonging to the equivalent scope of the claims will fall within the scope of the present invention.

Claims (21)

A green color filter comprising a color conversion member for converting the blue wavelength light emitted from the light emitting sources emitting blue and red wavelength light into the green wavelength light, and a red blocking member for blocking only the light of the red wavelength. The method of claim 1, The color conversion member is a coumarin-based green color filter including coumarin 6 or coumarin 7. The method of claim 1, The color conversion member is a green color filter of an inorganic or organic pigment. The method of claim 1, The transmittance of the red blocking member is a green color filter having a transmittance of 30% or less between 550 nm and 750 nm and a transmittance of 60% or more between 400 nm and 530 nm. The method of claim 1, The color conversion member and the red blocking member are each a green color filter forming an independent layer. The method of claim 1, The color conversion member and the red blocking member are mixed with each other to form a green color filter. Board, A first electrode formed on one surface of the substrate, An organic light emitting layer for emitting mixed light of blue and red wavelengths formed on the first electrode; A second electrode formed on the organic light emitting layer, It includes a green color filter formed in the green pixel region of the other surface of the substrate, The green color filter includes a color conversion member for converting light of blue wavelength emitted from the organic light emitting layer into light of green wavelength and red wavelength, and a red blocking member for blocking light of the red wavelength. The method of claim 7, wherein Wherein the mixed light has a color coordinate of X = 0.20 to 0.50 and Y = 0.20 to 0.43. The method of claim 7, wherein The blue light emitting material of the organic light emitting layer is Firpic, (3,5-diCF3ppy) Irpic, (3-CNppy) Irpic, (3,5-diCNppy) Irpic, SDI-BD-785, SDI-BD-735, and SBD02. An organic light emitting display device comprising one selected from the group consisting of. The method of claim 7, wherein The red light emitting material of the organic light emitting layer comprises one selected from the group consisting of (btp) 2Ir (acac), pq3Ir, pq2Ir (acac), DCM2, DCJTB. The method of claim 7, wherein And the color conversion member and the red blocking member each form an independent layer. The method of claim 11, The thickness of the first layer of the color conversion member is 1 to 30㎛, the thickness of the second layer of the red blocking member is 0.5 to 5㎛ organic light emitting display device. The method of claim 7, wherein And the color conversion member and the red blocking member are mixed with each other to form one mixed layer. The method of claim 13, The organic light emitting display device having a thickness of the mixed layer is 1 to 30㎛. Board, A first electrode formed on one surface of the substrate, An organic light emitting layer for emitting mixed light of blue and red wavelengths formed on the first electrode; A second electrode formed on the organic light emitting layer, and It is configured to include a green color filter formed on the outside of the second electrode, The green color filter includes a color conversion member for converting light of blue wavelength emitted from the organic light emitting layer into a green wavelength, and a red blocking member for blocking light of the red wavelength. The method of claim 15, The blue light emitting material of the organic light emitting layer is Firpic, (3,5-diCF3ppy) Irpic, (3-CNppy) Irpic, (3,5-diCNppy) Irpic, SDI-BD-785, SDI-BD-735, and SBD02. An organic light emitting display device comprising one selected from the group consisting of. The method of claim 15, The red light emitting material of the organic light emitting layer comprises one selected from the group consisting of (btp) 2Ir (acac), pq3Ir, pq2Ir (acac), DCM2, and DCJTB. The method of claim 15, And the color conversion member and the red blocking member each form an independent layer. The method of claim 18, The thickness of the first layer of the color conversion member is 1 to 30㎛, the thickness of the second layer of the red blocking member is 0.5 to 5㎛ organic light emitting display device. The method of claim 15, And the color conversion member and the red blocking member are mixed with each other to form one mixed layer. The method of claim 20, The organic light emitting display device having a thickness of the mixed layer is 1 to 30㎛.

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