WO2005003825A1

WO2005003825A1 - Blue color filter and organic electroluminescence device including the same

Info

Publication number: WO2005003825A1
Application number: PCT/JP2003/008279
Authority: WO
Inventors: Koji Kawaguchi; Ryoji Kobayashi; Kenya Sakurai
Original assignee: Fuji Electric Holdings Co., Ltd.
Priority date: 2003-06-30
Filing date: 2003-06-30
Publication date: 2005-01-13
Also published as: GB2409205A; DE10393386T5; AU2003246147A1; GB2409205B; CN1685251A; CN100388017C; GB0427182D0

Abstract

A blue color filter comprising a first dye represented by the structural formula (1) in the description and a binder resin and further comprising a second dye capable of absorbing fluorescence from the first dye and not exhibiting any fluorescence maximum in the visible wavelength region. This blue color filter realizes high blue color purity and transmission factor, being excellent in contrast and is suitable for use in an organic EL display. There is further provided an organic EL device including the same.

Description

Blue color filter and organic electroluminescence device using the same

The present invention relates to a blue color filter used for a display device of a portable terminal or an industrial measuring instrument, and an organic electroluminescent (hereinafter abbreviated as organic EL) device using the same. Background art

As one of the methods for producing a multi-color or full-color organic EL display, a color conversion method using a fluorescent material that absorbs light in an emission region of an organic luminous body and emits fluorescence in a visible light region as a filter is disclosed in Japanese Unexamined Patent Publication No. These are disclosed in, for example, JP-A-152897 and JP-A-5-258860. According to this method, the emission color of the organic light-emitting body is not limited to white, so that a higher-luminance organic light-emitting body can be applied to the light source. For example, using a blue-emitting organic light-emitting body, blue light is converted to green light or red light. A color conversion method for wavelength conversion is described in JP-A-3-52897, JP-A-8-286033, and JP-A-9-208944. If a fluorescent conversion film containing such a fluorescent dye is patterned on a transparent support substrate with high definition, a full-color image can be obtained even when using low-energy light such as near-ultraviolet light or visible light of an organic luminous body. A light emitting display can be constructed.

Organic EL devices using a color filter, a color conversion filter, and a color conversion method that includes an organic light-emitting element as components. For those requiring weather resistance and high-definition images, color filters prepared by the pigment dispersion method are mainly used, and red, blue or green pigments are added to the photosensitive resin solution. After applying a finely dispersed material with a particle size of 1 μηι or less on a glass substrate, The pixels are formed in a desired pattern by the luffy (see Japanese Patent Publication No. 4-37987, Japanese Patent Publication No. 4-39041, etc.).

Improvements in color purity, saturation, and light transmission of color filters have been demanded.In the past, to improve the light transmission, it was necessary to reduce the content of the coloring pigment in the photosensitive resin in the image forming material. Alternatively, a method of reducing the thickness of a pixel formed by an image forming material has been adopted.

However, in these methods, the saturation of the color filter itself decreases, the entire display becomes whitish, and the vividness of the colors required for display is sacrificed. Increasing the pigment content causes the entire display to become darker, and the amount of light from the packlight must be increased in order to ensure brightness, resulting in an increase in the power consumption of the display.

On the other hand, there is known a method for finely dispersing the particle size of pigment particles to 1/2 or less of the coloration wavelength in order to improve the light transmission amount (Kiyoshi Hashizume, Journal of the Color Materials Association, 1967 December, see _P 608) force blue pigment other red, for color wavelength as compared to the green pigment is short, require additional finely dispersed in this case, stable inhibit the cost and amount Chinochi Is a problem.

Further, as a blue pigment, copper phthalocyanine-based blue having α-type, ε-type and ε-type crystal forms is widely used (see Color Material Engineering Handbook, edited by the Color Material Association, ρ333). When α-type copper phthalocyanine blue is used alone in a color filter, its coloring power is low, and a large amount of pigment must be mixed with the photosensitive resin to achieve the desired saturation. However, there remains a problem in heat-resistant discoloration after the formation and adhesion to the glass substrate, and the amount of transmitted light having a power wavelength of 600 nm or more is large, and the color purity is reduced. On the other hand, when ε-type copper phthalocyanine pull is used alone as a blue pigment, it is possible to reduce the amount of addition to the photosensitive resin due to its excellent coloring power, but the desired saturation is reduced. Increasing the mixing amount of the pigment until it is obtained will cure the photosensitive resin There is a problem that the light-shielding property of 365nra, which is the wavelength, is increased, the photocuring sensitivity is reduced, and the film is peeled during development and the pattern flows.

Also, since / 3 type copper phthalocyanine blue is a greenish blue, using it alone as a blue pigment will result in a large deviation from the target NTSC hue. There is.

It is also known to use a pigment obtained by mixing a copper phthalocyanine blue and a dioxazine biolet for a color filter (see Japanese Patent Publication No. 6-95211, Japanese Patent Publication No. 1-200353, Japanese Patent Publication No. 4-37987, etc.). Using the color mixture of any one of the above three types of copper lid mouth cyanine blue and dioxazine-based violet pigment violet 23, light transmission of 500 to 550 nm can be suppressed and color purity can be reduced. However, there is a problem in that light transmission in the target blue region of 420 to 500 nm is suppressed, and the brightness of a display is reduced. Furthermore, when used as a display, the light transmittance in the blue region is suppressed to 70 to 80% by the polarizing plate compared to the other color regions, so there is a need to improve the light transmittance of the blue filter. .

An object of the present invention is to provide a blue color filter having a high blue transmittance and a low green transmittance, a good blue purity, and an organic electroluminescent device. Disclosure of the invention

In order to achieve the above object, in the present invention, a blue color filter contains a first dye represented by a structural formula (1) and a binder resin, and emits fluorescence of the first dye. It contains a second colorant that absorbs and does not have a fluorescence maximum in the visible wavelength region.

[Structural formula (1)]

[In the structural formula (1), Ri Re represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group which may be independently substituted, and R ₇ is a chain unsaturated hydrocarbon having 1 to 6 carbon atoms. Represents a group. ΧΊ Also, I-, B r-, C 1- , F -, C 10 3 -, B r 0 3 _, I 0 3 -, C 10 4 -, BF have _{_{PF 4 -, S b F 4}} -, B r 0 ₄ —and represents an anion selected from the group of organic anions]

By using the first dye represented by the structural formula (1) as the blue dye of the blue color filter as described above, the light transmittance of 500 nm to 600 nm can be suppressed to improve the blue purity, It enables a blue color filter with high transmission. In addition, by incorporating a second dye that absorbs the fluorescence of the first dye and does not have a fluorescence maximum in the visible wavelength range of 750 nm or less together with the first dye, the first dye is The resulting dye of 600 nm to 700 nm is absorbed by the second dye to prevent a decrease in blue purity.

The present invention also provides that the blue color filter contains the first dye represented by the structural formula (1) and a binder resin, and also contains the second dye represented by the structural formula (2) .

[Structural formula (1)]

In Structural Formula (1), Ι ^ ~Ι ₆ each independently represent a an optionally substituted hydrogen atom, an alkyl group, Ariru group or a heterocyclic group,, R ₇ is not chain having 1 to 6 carbon atoms Represents a saturated hydrocarbon group. X- is厂, B r-, CI-, F-, C 1 0 3 B r 0 3 one,

_{I 0 3 -, C 1 0} 4 -, BF 4 -, PF 4 - represents a Ayuon selected from the group of organic Anion] -, S b F, B r 0 4

[Structural formula (2)]

[In the structural formula (2), represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. X- is厂, B r -, C 1-, F-, C 1 0 3 -, B r 0 3 -, I 0 3 _{one, C 1 O 4 -, BF} 4 -, PF 4 -, S b F ₄ —, Br 0 ₄ — and anion selected from the group of organic anions. Y represents an O atom or an S atom. a represents an integer of 1 to 6. ]

Still further, the blue color filter of the present invention may contain a quencher anion for quenching the fluorescence of the first or second color element.

The organic electroluminescent device according to the present invention uses the blue color filter as at least a part of the color filter. Brief Description of Drawings

FIG. 1 is a schematic cross-sectional view of an organic EL device having a blue color according to the present invention.

(Explanation of symbols)

1 0 0 Organic EL device

1 0 Transparent support substrate 2 0 Blue color filter,

3 0

4 0 Inorganic oxide film

500 organic light emitter

5 0

5 1 Hole injection layer

5 2 Hole transport layer

5 3

5 4 Electron injection layer

5 5 BEST MODE FOR CARRYING OUT THE INVENTION

As shown in FIG. 1, the organic EL device 100 of the present example has a blue color filter 20, an organic protective layer 30, an inorganic oxide film 40, a transparent anode 50, and a positive electrode on a transparent support substrate 10. A hole injection layer 51, a hole transport layer 52, a light emitting layer 53, an electron injection layer 54, and a cathode 55 are sequentially formed to constitute an organic EL device 100 as a whole.

Next, each material used for adjusting the blue image forming material for forming the blue color filter 20 of the present invention will be described.

[First dye]

The blue color filter of the present invention contains a cyanine dye represented by the structural formula (1) as a first dye. The dye represented by the structural formula (1) may be used alone or in combination of two or more. Since the cyanine dye represented by the structural formula (1) has high chemical and thermal stability itself, the heat resistance of the blue color filter is high even without using the pigment dispersion method. Further, another blue pigment such as a copper phthalocyanine-based pigment may be mixed with the first pigment. In obtaining the blue image forming material of the present invention, the mixing ratio of the cyanine dye represented by the structural formula (1) to the binder resin is preferably 0.1 to 40 parts by weight. As a result, it is possible to suppress transmission of light in the range of 500 to 550 nm, and to improve color purity. Further, the cyanine dye represented by the structural formula (1) can be used after being pigmented, and a known method can be used as a method for producing a blue pigment dispersion. For example, a copper phthalocyanine-based blue and a cyanine-based colorant represented by the structural formula (1) are mixed with an organic solvent, a pigment derivative (added as necessary) for dispersing stability and a dispersant, and a dispersing machine such as a sand mill. By finely dispersing and stabilizing the pigment using, a blue pigment dispersion containing copper phthalocyanine blue and a cyanine dye represented by the structural formula (1) is also excellent.

[Second dye]

A dye that absorbs the fluorescence (600 nm to 700 nm) of the first dye and has no fluorescence in the visible wavelength range (750 nm or less) is added as the second dye. The mixing ratio of the second dye to the binder-resin is preferably from 0 :! to 40 parts by weight. In order to function as a blue color filter, a dye that does not absorb light in the blue wavelength region is desirable. Specifically, any dye can be used as long as it has a transmittance of 60% or more at 450 nm when added to a filter.

Examples are 1, 1-Diethyl-4,4-carbocyanine Iodide (uryptocyanine), 1, 1-Diethyl—2,2, —dicarbocyanine Iodide (DDI), 3,3′—

Diraethyloxatri carbocyanine Iodide (Methyl D0TCI), 1,, 3, 3, 3, 3, 3 '-

Hexamethylindotricarbocyanine Iodide (HITCI), IR125 (from Lambda Phisik), 1,1'-Diethyl-4,4'-carbocyanine Iodide (Cryptocyanine), IR144 (from Lambda Phisik), 3, 3'-Diethyl-9,11- neopentylenethiatricarbocyanine Iodide (DNTTCI), 1, 1 ', 3, 3, 3', 3'-Hexamethyl-4, 4 '5, 5' dibenzo— 2, 2 'one

Indotricarbocyanine Iodide (HDITCI), 1,2′-Diethyl-4, 4′-dicarbocyanine Iodide (DDCI-4) and the like. Alternatively, a cyanine dye represented by the structural formula (2) may be used as the second dye. Specifically, for example, 3,3′-Diethylthiatricarbocyanine Iodide (DTTCI), 3,3, -Diethyl-4, 4 '5,5'-dibenzothiatricarbocyanine Iodide (DDTTCI).

[Structural formula (2)]

[In the structural formula (2), represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. X- is,, B r-, C l F- , C 1 O 3 -, B r 0 3 -, I 0 3 primary,

_{_{C 1 0 4 -, BF 4}} -, PF, S b F 4 - represents a § two on selected from the group consisting of and organic Anion -, B r 0 _4. Y represents an O atom or an S atom. a represents an integer of 1 to 6. ]

[Taengya]

Since the dye to be used is a cationic dye, the quencher may be, for example, an ionic singlet oxygen quencher. Specifically, transition metal chelates, bisimidium salts and the like disclosed in JP-A-59-57979, JP-A-60-234892, etc. are used. it can.

Layender]

The binder resin used in the blue color filter of the present invention may be any resin that has visible light transmittance and good adhesion to a substrate, and may be a known thermoplastic resin, thermosetting resin, or photocurable resin. Etc. can be used. A resin having photosensitivity is particularly preferable because a fine pattern of the filter can be easily prepared.

[Production of blue color filter and organic EL device] The blue color filter layer 20 is formed by applying a blue image forming material composed of each of the above-mentioned materials on the transparent support substrate 10 in a desired pattern. The coating method is not particularly limited, and a usual spin coating method, roll coating method, casting method, screen printing method, ink jet method and the like can be used. There is no particular limitation on the curing method, and heat curing (preferably curing at a temperature of about 150 ° C. in consideration of deterioration of the fluorescent material), moisture curing, chemical curing, and light curing (inferiority of the fluorescent material) It is desirable to cure with visible light in consideration of the dangling.) Furthermore, the dangling method combining these can be used.

Before or after forming a blue pixel, a multicolor filter can be formed by forming a red or / and green color filter using a red or / and green pixel forming material as needed. Can be made. Further, a multicolor organic EL device can be manufactured by laminating an organic light emitting element 500 on this color filter via an organic protective layer 30 and an inorganic oxide film 40. As a method of laminating the organic luminescent material 500, a transparent anode 50, a hole injection layer 51, a hole transport layer 52, a light emitting layer 53, an electron injection layer 54, and a cathode are provided on the upper surface of the color filter. A method of sequentially forming 55, a method of bonding an organic light-emitting body 500 formed on another substrate to an inorganic oxide film 40, and the like can be given. The organic EL device 100 manufactured in this manner can be applied to a passively driven organic EL display and an actively driven organic EL display.

Hereinafter, examples will be described.

(Example 1)

[Production of black mask]

Although not shown in FIG. 1, in order to eliminate the influence of the reflected light at the end of the blue color filter 20 and the transparent electrode 50 at the time of the contrast evaluation, the transparent support substrate 10 is used to remove the blue color filter 20 from the end. First, a black mask was provided for the purpose of making the part invisible. A black mask coating solution (CK8400L, manufactured by Fuji Film ARCH) is applied to the entire surface of the transparent support substrate 10 made of glass by spin coating, dried by heating at 80 ° C, and then dried by photolithography. A striped black mask pattern with a pitch of 13 mm and a gap of 0.1 Omm was obtained.

[Production of blue color filter]

Using a transparent photopolymerizable resin (259 PAP5, manufactured by Nippon Steel Chemical Co., Ltd.) as a binder, and a dye represented by the structural formula (3) as a blue dye based on 100 parts by weight of the solid content of the transparent photopolymerizable resin. Was added, and 1 part by weight of a second dye represented by Structural Formula (4) (HDITCI manufactured by Lambda Physik) was added to obtain a coating solution for a blue color filter.

[Structural formula (3)]

ti 3

[Structural formula (4)]

This blue color filter coating liquid is applied on a transparent support substrate 10 by spin coating, heated and dried at 80 ° C., and then subjected to photolithography to obtain a 0.13 mm pitch. A blue color filter pattern having a stripe shape with a gap of 0.01 mm was formed.

[Production of organic EL device]

After forming a blue color filter 20 on one main surface of the transparent support substrate 1 made of glass by the above-described method, an organic protective layer 30 and an inorganic oxide layer 40 are sequentially formed on this blue upper surface, and further thereon. The organic luminous body 500 was formed to produce an organic EL device 100. The organic luminescent layer 500 is composed of six layers including a transparent anode 50 Z hole injection layer 51 / hole transport layer 52, a light emitting layer 53, an electron injection layer 54, and a cathode 55. The specific fabrication procedure will be described below. .

A transparent photopolymer resin (259 PAP5, manufactured by Nippon Steel Chemical Co., Ltd.) is applied on the transparent support substrate 10 on which the blue color filter 20 is formed, and dried to form a blue color filter 20. An organic protective layer 30 having a thickness of 5 μπι was formed, and an inorganic oxide layer 40 made of SiO _{2 having} a thickness of 100 nm was formed thereon by sputtering. Subsequently, a layer made of ITO was similarly formed on the entire surface of the inorganic oxide layer 40 by sputtering, and the transparent anode 50 was obtained by performing the following patterning. That is, after applying a resist agent (0FRP-800, manufactured by Tokyo Ohka Co., Ltd.) to a thickness of 100 nm on the ITO film, a 0.113 mm line pitch, 0.03 mm A transparent anode 50 having a stripe pattern of 1 mm gap was used.

Next, this substrate was mounted in a resistance heating evaporation apparatus, and a hole injection layer 51, a hole transport layer 52, a light emitting layer 53, an electron injection layer 54, and a cathode 55 were formed in this order without breaking vacuum. . The pressure in the vacuum chamber during film formation was reduced to 1 × 10 ” ⁴ Pa. Specifically, the hole injection layer 51 was a 100 nm thick copper phthalocyanine (CuPc) layer, and the hole transport layer 52 is a 20 nm thick 4,4'-bis [N- (1-naphthyl) -N-phenylamino] biphenyl (-NPD) layer, and the light emitting layer 53 is a 30 nm thick 4,4'-bis (2 The biphenyl (DPVBi) layer, the electron injection layer 54 was a 20 nm-thick tris (8-hydroxyxinoline) aluminum complex (Alq) layer, and the cathode had a thickness of 20 nm. Mg / Ag consisting of Onm (weight ratio 1:10) was formed into a stripe pattern with a pitch of 0.33 mm and a gap of 0.05 mm perpendicular to the anode line by mask evaporation.

After the formation of each layer, the organic EL element 100 was taken out of the vapor deposition apparatus, and sealed under a nitrogen atmosphere using a sealing glass and a UV adhesive so that the element was not directly exposed to the atmosphere. (Not shown). The manufactured organic EL device 100 emits blue light having a peak at a wavelength of 47 Onm.

(Example 2)

In forming the blue color filter in Example 1, the dye represented by Structural Formula (5) was used as the second dye instead of the second dye used in Example 1, and a transparent photopolymerizable resin solid content of 100 parts by weight was used. An organic EL device was produced in the same manner as in Example 1 except that 1 part by weight of the organic EL device was added.

[Structural formula (5)]

(Example 3)

In the formation of the blue color filter in Example 2, Example 2 was repeated except that the nickel complex represented by the structural formula (6) was added as a quencher in a ratio of 0.3 mol to 1 mol of the first dye. A coating solution for a blue color filter was prepared in the same manner as described above, and an organic EL device was similarly obtained.

[Structural formula (6)]

(Comparative Example 1) A coating material for a blue color filter was prepared in the same manner as in Example 1, except that the phthalocyanine blue was used as the pigment instead of the first dye and the second dye used in Example 1. The amount of the pigment added was adjusted so that the light transmittance at a wavelength of 470 nm was the same as that in Example 1 when the blue color filter was formed in the same thickness as in Example 1.

(Evaluation)

The following evaluation was performed about the produced sample. Table 1 shows the evaluation results. Here, the CIE chromaticity was evaluated by making the manufactured device emit light. A chromaticity meter (MCPD-1000, Otsuka Electronics Co., Ltd.) was used for the measurement. The contrast was compared when the display surface of the device was irradiated with fluorescent light (100000) from an oblique angle of 45 °. The values in the table are relative values with the result of the comparative example as 1 · 0. If the value is 1.0 or more, the contrast is improved. The transmittance was measured using a spectrophotometer (Shimadzu UV-210 PC), and the light transmittance at wavelengths of 470 nm and 510 nm was compared. .

[table 1 ]

As shown in Table 1, the light transmittance at 510 nm when the films were formed with the same light transmittance at 470 nm was higher in the example than in the comparative example. This means that the color filter of the example has a higher light-shielding property in a wavelength range that reduces the purity of blue than the color filter of the comparative example. Further, in the color filter of the comparative example in which the pigment is dispersed in the binder, scattering is liable to occur in the color filter and at the interface. On the other hand, it is considered that the color filter of Example shows a value in which the dye is completely dissolved in the binder, the transparency is high, and the contrast is high. Industrial applicability

According to the present invention, it is possible to provide a blue color filter suitable for an organic EL display, which has high purity and transmittance of blue and has good contrast, and an organic EL element using the same.

Claims

The scope of the claims

1. A second dye that contains the first dye represented by the structural formula (1) and a binder resin, absorbs the fluorescence of the first dye, and does not have a fluorescence maximum in the visible wavelength region. A blue color filter, characterized by containing the following dyes.

[Structural formula (1)]

[In the structural formula (1),

Represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group which may be independently substituted, and R ₇ represents a chain unsaturated hydrocarbon group having 1 to 6 carbon atoms. X- is, I-, B r-, CI-, F-, C 10 3 -, B r 0 3 \ I 0 3 -, C 10 4 -, BF 4 -, PF 4 -, S b F 4 - , Br O and anion selected from the group of organic aions]

2. A blue color containing a first dye represented by Structural Formula (1), a binder resin, and a second dye represented by Structural Formula (2). filter.

[Structural formula (1)]

[In the structural formula (1), 1 ^ to ₁₆ each independently represent a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group which may be substituted, and R ₇ represents a chain of 1 to 6 carbon atoms. Represents a saturated hydrocarbon group. X- is, I _, B r-, CI- , F _{one, C 1 0 3 -, B} r 0 3 one,

IO ₃ —, C 1 O ₄ —, BF ₄ —, PF ₄ —, S b F or Br 0 ₄ — and an anion selected from the group of organic anions]

[Structural formula (2)]

[In the structural formula (2), represents a hydrogen atom, an alkyl group, an aryl group, or a heterocyclic group. X- is, I-, B r -, C , F -, C 1 0 3 -, B r 0 3 I 0 3 C 1 0 4 -, BF have _{_{PF 4 -, S b F 4}} -, B r 0 ₄ — and represents anion selected from the group of organic anions. Y represents an O atom or an S atom. a represents an integer of 1 to 6. ]

3. The blue color filter according to claim 1, further comprising a quencher anion for quenching the fluorescence of the first or second dye.

4. In an organic electroluminescence element in which an organic luminous body and a color filter are laminated, at least a part of the color filter is described in any one of claims 1 to 3 and claim 1. An organic electroluminescent element characterized by being a blue color filter.