JP2001249222A - Antireflection film and light emitting display element using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an antireflection film which can effectively prevent light reflection by the reflective surface having a large reflexivity, such as a metal electrode incorporated in an electroluminescence display element, with a wideband wavelength, and to provide a display element using the same. SOLUTION: The antireflection film is composed of a phase difference film consisting of one polymeric oriented film whose phase differences in the wavelengths of 450 nm and 550 nm easily |R(450)|<|R(550)| and a polarizing plate wherein |R(450)| and |R(550)| are the absolute values (nm) of the intra-plane phase difference in the wavelengths of 450 nm and 550 nm, respectively.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antireflection film and a light emitting device using the same, and as the light emitting device,
In particular, the present invention relates to a display element suitable for an organic electroluminescent display using an organic thin film for an electroluminescent layer, and an antireflection film useful therein.

[0002]

2. Description of the Related Art A light-emitting element, particularly an organic electroluminescent element (sometimes referred to generally as an organic EL element) has a metal electrode on the back side of a light-emitting layer for an observer, so that external light is not emitted. Due to the presence, the reflected light from the metal electrode is generated, and the scene on the observer's side is reflected, so that there is a problem that the display quality is significantly lowered. There is already known a technique in which a circularly polarizing plate is used as an antireflection film on a front substrate of a light emitting element in order to prevent the metal reflection. The circularly polarizing plate is composed of a polarizing plate and a retardation film that is a quarter-wave plate. As the retardation film, a technique using a polymer oriented film obtained by stretching a polymer film or the like is disclosed.

When such a conventional retardation film is used as a circularly polarizing film, a good antireflection effect can be obtained only at a specific wavelength at which the retardation is a quarter wavelength. For example, good anti-reflection cannot be obtained in a wide band of wavelengths of 400 nm to 700 nm, and as a result, there is a problem that reflected light is colored.

On the other hand, there has been proposed a technique for improving the wavelength dispersion characteristics of the retardation by using a plurality of retardation films to solve these problems.

However, when such a plurality of retardation films are used, the cost is required because an adhesive is required between the films, the yield is reduced, and a complicated optical design is required. There are many problems, such as becoming very expensive.

[0006]

SUMMARY OF THE INVENTION An object of the present invention has been made in view of the above-mentioned circumstances, and has been made by a highly reflective reflecting surface such as a metal electrode incorporated in an electroluminescent display element. An object of the present invention is to provide an antireflection film capable of effectively preventing light reflection in a wide wavelength range, and a display element using the same.

[0007]

SUMMARY OF THE INVENTION The present invention seeks to realize an ideal λ / 4 plate independent of wavelength in a visible light wavelength region in a polymer oriented film, and finds that a phase difference is reduced. The present inventors have found that one polymer oriented film having a smaller wavelength as the wavelength becomes shorter is provided, and the above object is achieved by combining this with a polarizing plate, and an anti-reflection film having excellent properties which has not been obtained conventionally and using the same. Thus, a light-emitting element has been provided.

That is, the present invention is characterized by comprising a polarizing plate and a retardation film comprising one polymer oriented film and having a retardation at wavelengths of 450 nm and 550 nm satisfying the following formula (1). It is an anti-reflection film.

[0009]

| R (450) | <| R (550) | (1) (In the above equation (1), | R (450) |, | R (55
0) | is the absolute value (nm) of the in-plane retardation at wavelengths of 450 nm and 550 nm, respectively. )

The present invention also provides a light-emitting device having the above-described antireflection film provided on a light-emitting side, particularly a substrate, a transparent electrode, a hole-transporting layer, a light-emitting layer, an electron-transporting layer, and a metal electrode layer in order from the light-emitting side. Wherein the antireflection film is provided on the light emission side.

The fact that the retardation of the retardation film becomes smaller as the wavelength becomes shorter can be expressed by the above formula (1) from a practical viewpoint, but R (450) and R (550) need to have the same sign. is there. The present invention is an antireflection film composed of a retardation film and a polarizing plate that satisfies the above formula (1) in one sheet, and in particular, a film having a quarter-wave retardation as a light-emitting element, In particular, when used in a light-emitting element in which reflection of a metal electrode poses a problem in the presence of external light, a very excellent light-emitting element can be provided.

The retardation film of the present invention needs to satisfy the above-mentioned formula (1), but has or has a phase difference of a quarter wavelength for all wavelengths in the visible light region. It is more preferable to take a value.

Here, the principle by which the antireflection film of the present invention can prevent reflection in a light emitting device, particularly an organic electroluminescent device, will be described with reference to FIG.

In FIG. 2, reference numeral 1 denotes external light, which becomes linearly polarized light 2 after passing through the polarizing plate 13. Then, after passing through the retardation film 14, which is a quarter wavelength, clockwise (or counterclockwise)
It becomes circularly polarized light. Reference numerals 7, 8, 9, 10, and 11 denote a substrate, a transparent electrode, a hole transport layer, a light-emitting layer, and an electron transport layer, respectively. Since these are optically isotropic, the polarization state of 3 hardly changes and 12 Reaches the metal electrode layer. After reflection, the polarization state changes to left-handed (or right-handed) circularly-polarized light as indicated by 4, and after passing through the 14 retardation films again, it becomes linearly-polarized light 5 180 degrees out of phase with linearly-polarized light 2. Therefore, the linearly polarized light 5 cannot pass through the polarizing plate 13 and absorbs external light, thereby exhibiting an antireflection function. In FIG. 2, the polarizing plate 13 and the retardation film 14 appear to be separated from the substrate 7, but this is for the purpose of explaining the principle. Actually, they are in close contact with each other using an adhesive or the like. Is preferred from the viewpoints of luminance enhancement and antireflection effect.

Reference numeral 6 denotes light emitted from the light-emitting element, which is usually non-polarized light.
Is not affected. Light is absorbed to some extent in the polarizing film 13 but can be transmitted. The light emitted from the light-emitting layer 10 is generally unpolarized light, but may be polarized light for improving luminance.

The above description is about the wavelength at which the retardation of the retardation film is in a state of a quarter wavelength or close to it in the visible light region. The polarized light becomes circularly polarized light, the reflected light does not leak, there is little coloring, and the contrast is good. In general, a retardation film made of a normal polymer material has characteristics completely opposite to those of an ideal quarter-wave plate such that the retardation is small on the long wavelength side and large on the short wavelength side. In this case, it is possible to prevent reflection of light of a specific wavelength, but this is very inconvenient in the case of a light emitting element that requires display quality.

Although the above description has been made with respect to an organic electroluminescent device in particular, the antireflection film of the present invention can be used for other electroluminescent devices such as an inorganic electroluminescent device, a field emission display device, a plasma display device and the like. .

The principle that the retardation film in the present invention is realized by one polymer oriented film having a smaller retardation as the wavelength becomes shorter will be presumed below. It has been found that such a retardation film can be obtained by a polymer oriented film satisfying the following condition (A) or (B).

(A) (1) A polymer monomer unit having a positive refractive index anisotropy (hereinafter referred to as a first monomer unit) and a polymer monomer unit having a negative refractive index anisotropy ( (Hereinafter referred to as a second monomer unit). (2) A polymer based on the first monomer unit, wherein R (450) / R (550) of the polymer is R (450) / R (55) of the polymer based on the second monomer unit
(3) A polymer oriented film having a positive refractive index anisotropy smaller than 0).

(B) (1) Forming a monomer unit forming a polymer having a positive refractive index anisotropy (hereinafter referred to as a first monomer unit) and a polymer having a negative refractive index anisotropy A film comprising a monomer unit (hereinafter referred to as a second monomer unit) comprising: (2) a polymer R (4) based on the first monomer unit;
50) / R (550) is larger than R (450) / R (550) of the polymer based on the second monomer unit, and (3) has a negative refractive index anisotropy. the film.

As an example of an embodiment satisfying the above conditions (A) and (B), there is one satisfying the following conditions (C) and (D).

(C) (1) A blended polymer composed of a polymer having a positive refractive index anisotropy and a polymer having a negative refractive index anisotropy and / or having a positive refractive index anisotropy. A film comprising a copolymer comprising a polymer monomer unit and a polymer monomer unit having a negative refractive index anisotropy, wherein (2) the polymer having a positive refractive index anisotropy R (450) / R (550) is smaller than R (450) / R (550) of the polymer having the negative refractive index anisotropy, and (3) has a positive refractive index anisotropy. , Polymer oriented film.

(D) (1) A blend polymer comprising a polymer having a positive refractive index anisotropy and a polymer having a negative refractive index anisotropy and / or having a positive refractive index anisotropy A film comprising a copolymer comprising a polymer monomer unit and a polymer monomer unit having a negative refractive index anisotropy, wherein (2) the polymer having a positive refractive index anisotropy R (450) / R (550) is larger than R (450) / R (550) of the polymer having the negative refractive index anisotropy, and (3) has a negative refractive index anisotropy. , Polymer oriented film.

Here, the polymer having a positive or negative refractive index anisotropy refers to a polymer giving a polymer oriented film having a positive or negative refractive index anisotropy.

The reason why the retardation film is a necessary condition that the retardation becomes smaller as the measurement wavelength becomes shorter will be described below.

In general, it is known that the birefringence Δn of a polymer blend composed of two components, polymer A and polymer B, is expressed as follows. (H. Saito and T. Inoue,
.. J. Pol Sci Part B, 25, 1629 (1987)) Δn = Δn 0 A fA φA + Δn 0 B fB φB + ΔnF (a) where, Δn ⁰ A: intrinsic birefringence of polymer A, Δn ⁰ B
: Intrinsic birefringence of polymer B, fA: orientation function of polymer A, fB: orientation function of polymer B, φA: volume fraction of polymer A, φB: volume fraction of polymer B (= 1-1) φA),
ΔnF: structural birefringence. In general, the birefringence Δn is Δ
It is represented by n = fΔn ⁰ . Δn ⁰ can be determined by combining dichroic infrared spectroscopy with phase difference measurement.

Although the change in polarizability due to the electronic interaction between the polymers A and B is completely ignored in the equation (a), this assumption will be adopted in the following. Further, in the retardation film application as in the present invention, the blend is preferably a compatible blend because it is required to be optically transparent. In this case, ΔnF is extremely small and is ignored. I can do it.

Next, the retardation film whose birefringence becomes smaller as the measurement wavelength becomes shorter is considered here. Only 450 and 550 nm are considered here as this measurement wavelength. Assuming that the birefringence of the retardation film at these wavelengths is Δn (450) and Δn (550), respectively, Δn (450) / Δ
n (550) <1. It is needless to say that a retardation film composed of an ordinary polymer film has Δn (450) / Δn (550)> 1, and, for example, Δn (450) / of a polycarbonate obtained from polymerization of bisphenol A and phosgene.
Δn (550) is about 1.08, and is about 1.01 even for polyvinyl alcohol, which is said to have small birefringence wavelength dispersion.

Assuming that Δn (450) / Δn (550) is a birefringence wavelength dispersion coefficient, it is expressed as follows using the equation (a). Δn (450) / Δn (550 ) = (Δn 0 A (450) fA φA + Δn 0 B (450) fB φB) / (Δn 0 A (550) fA φA + Δn 0 B (550) fB φB) (b)

Here, since it is a miscible blend, fA =
Assuming fB, equation (b) can be written as: Δn (450) / Δn (550 ) = (Δn 0 A (450) φA + Δn 0 B (450) φB) / (Δn 0 A (550) φA + Δn 0 B (550) φB) (c)

Next, virtual values as shown in Table 1 are shown in (c).
The birefringence wavelength dispersion value was examined using the equation. In Table 1, the birefringence dispersion values of the polymers A and B alone are shown instead of Δn ⁰ A (450) and Δn ⁰ B (450).

[0032]

[Table 1]

Equation (c), given the values in Table 1, is expressed as a function of φA as shown in FIGS. Cases 1 to 4 correspond to FIGS. In Table 1, the polymer having the positive refractive index anisotropy is defined as the polymer A, and the polymer having the negative refractive index anisotropy is defined as the polymer B. Therefore, φ is smaller than the asymptote shown in FIGS.
In the region where A is small, the optical anisotropy of the blend polymer is negative, while in the region where φB is larger than the asymptote, the anisotropy is positive.

As apparent from FIGS. 3 to 6, Δn (450)
/ Δn (550) <1 for cases 1 and 3 in Table 1.
The positive polymer has a birefringence wavelength dispersion coefficient smaller than that of the negative polymer and the optical anisotropy of the polymer oriented film is positive, or the polymer alone is used as in Cases 2 and 4. It is necessary that the birefringence wavelength dispersion coefficient is larger than the negative one and the optical anisotropy of the polymer oriented film is negative.
Here, 450 and 550 nm were used as typical wavelengths,
The same holds for other wavelengths.

Considering the equation (c), if the birefringence wavelength dispersion coefficients of the positive and negative polymers are completely equal,
The retardation film of the present invention cannot be obtained.

The above considerations are based on the above formula (a). However, since this idea holds very well in an actual system as in the examples described later, it is considered that this idea is correct even in the examples. Proven.

While the above discussion has described two components,
The above concept holds even with components or more. For example, in a system in which two components having positive optical anisotropy and one component having negative anisotropy, the birefringence value and the birefringence dispersion value of the component having positive optical anisotropy Can be corrected by the volume fraction between two components having positive anisotropy and the like, and the two components can be regarded as one component, and the concept of the consideration given by the above equation (a) can be applied.

Although the description based on the above formula (a) has been described as a blend of the polymers A and B, the above-described consideration is similarly applied to a copolymer in which the polymer contains different monomer units. And a homopolymer (polymer A) based on the first monomer unit and a second polymer different from the first monomer unit.
The above concept may be applied assuming that the polymer consists of a homopolymer (polymer B) based on the above monomer unit.

Further, the above considerations can be similarly applied to a polymer blend of a homopolymer and a copolymer or a polymer blend of copolymers. That is, in this case, the polymer blend is divided into the monomer units constituting the component polymer, and the polymer blend is regarded as an aggregate of a homopolymer composed of the respective monomer units. The above consideration may be applied assuming a combination of the component A consisting of the homopolymer group having anisotropy and the component B consisting of the homopolymer group having a negative anisotropy.

For example, polymers X and Y having positive optical anisotropy and monomer units x and z having negative optical anisotropy
When x has a positive optical anisotropy and z has a negative optical anisotropy, the component having a positive optical anisotropy is represented by X, Y and x. Considering these, the birefringence value, the birefringence dispersion value, and the like are corrected by the volume fraction between the three components with positive anisotropy, and these three components are regarded as one component A. The component having the property is regarded as a polymer B composed of the monomer unit z, and for the component A and the component B,
What is necessary is just to apply the concept of the following considerations (a).

In the case of a homopolymer based on the first or second monomer unit, when the homopolymer is a polycarbonate, one of the methods widely used in the polycarbonate polymerization method is the polymerization of a dihydroxy compound and phosgene. Since it is obtained by condensation, a dihydroxy compound composed of bisphenol and phosgene are monomers from the viewpoint of polymerization. As described above, in the case of polycarbonate, the monomer unit refers to a portion derived from bisphenol, and does not include a portion derived from phosgene.

[0042]

BEST MODE FOR CARRYING OUT THE INVENTION The antireflection film of the present invention comprises:
Wavelength 450nm and 550
It is characterized by comprising a retardation film and a polarizing plate having a retardation in nm satisfying the following expression (1). R (450),
R (550) must have the same sign.

[0043]

| R (450) | <| R (550) | (1)

The retardation film preferably has a quarter-wave retardation, that is, a λ / 4 plate. Here, the fact that the phase difference is a quarter wavelength means that the measurement wavelength is 55
It is assumed that the wavelength is a quarter wavelength with respect to 0 nm. The antireflection film of the present invention is assumed to be mainly used in a display element, and is defined using 550 nm, which is a wavelength at which the visibility of human eyes is relatively high. Specifically, the measurement wavelength is 5
At 50 nm, the range of the phase difference value R (550) is 100 nm ≦ R (550)
≦ 170 nm, more preferably 120 nm ≦
R (550) ≦ 155 nm.

Preferably, the retardation wavelength dispersion of the retardation film is a retardation value R (45 nm) at a measurement wavelength of 450 nm, 550 nm, or 650 nm.
0), R (550) and R (650), the following formulas (2) and (3)

[0046]

0.6 <R (450) / R (550) <0.97 (2) 1.01 <R (650) / R (550) <1.4 (3) . It is more preferable to satisfy the following expressions (4) and (5).

[0047]

0.70 <R (450) / R (550) <0.90 (4) 1.03 <R (650) / R (550) <1.25 (5)

When a quarter-wave phase difference is completely given at the measurement wavelengths of 450 nm, 550 nm, and 650 nm, the phase difference values are R (450) = 112.5 nm, R (550) = 137.5 nm, and R (450), respectively. 650) = 162.5
nm, each of the above chromatic dispersion values is R (450)
/R(550)=0.818 and R (650) / R (550) = 1.182.
By setting the range of the wavelength dispersion of such a phase difference,
An antireflection effect can be obtained in a wide range of visible light, and when used in a light-emitting element, it has excellent contrast in the presence of external light and can prevent problems such as reduction in visibility such as coloring.

The principle of the material for satisfying the above characteristics with one polymer oriented film has already been described, and a specific material will be described below.

The polymer oriented film has a glass transition temperature of 120 ° C. or higher, preferably 140 ° C. or higher. If the temperature is lower than 120 ° C., a problem such as relaxation of orientation may occur depending on the use conditions of the light emitting element. Further, the water absorption is preferably 1% by weight or less. If the water absorption of the polymer oriented film is not 1% by weight or less, there may be a problem in practical use as a retardation film, and the film material has a water absorption of 1% by weight or less, preferably 0.5% by weight or less. It is good to select so as to satisfy the condition of

The oriented polymer film used in the present invention may be composed of a blended polymer or a copolymer.

The polymer material constituting the polymer oriented film used in the present invention is not particularly limited, and has excellent heat resistance.
Good optical performance, a material capable of forming a solution, for example, polyarylate, polyester, polycarbonate, polyolefin, polyether, polysulfine copolymer,
Thermoplastic polymers such as polysulfone and polyethersulfone are preferred.

When this thermoplastic polymer is used, as described above, a blend polymer comprising a polymer having a positive refractive index anisotropy and a polymer having a negative refractive index anisotropy,
A copolymer comprising a polymer monomer unit having a positive refractive index anisotropy and a polymer monomer unit having a negative refractive index anisotropy is more preferable. These may be used in combination of two or more, or one or more blended polymers and one or more copolymers may be used in combination.

Since a blended polymer needs to be optically transparent, it is preferable that a compatible blend or a refractive index of each polymer is substantially equal. As a specific combination of blended polymers, for example, a polymer having negative optical anisotropy is poly (methyl methacrylate)
And at least one polymer selected from the group consisting of poly (vinylidene fluoride), poly (ethylene oxide) and poly (vinylidene fluoride-co-trifluoroethylene) as a polymer having positive optical anisotropy In combination, a polymer having a positive optical anisotropy is poly (phenylene oxide), and a polymer having a negative optical anisotropy is polystyrene, poly (styrene-co-
Lauroylmaleimide), a combination of at least one polymer selected from the group consisting of poly (styrene-co-cyclohexylmaleimide) and poly (styrene-co-phenylmaleimide), and poly (styrene-copolymer having negative optical anisotropy). -Maleic anhydride) and a polycarbonate having a positive optical anisotropy, a poly (acrylonitrile-co-butadiene) having a positive optical anisotropy and a poly (acrylonitrile-co) having a negative optical anisotropy -Styrene), and a combination of a polycarbonate having a positive optical anisotropy and a polycarbonate having a negative optical anisotropy, but the present invention is not limited thereto. In particular, from the viewpoint of transparency, polystyrene and poly (2,6-dimethyl-
A blend polymer in which a poly (phenylene oxide) such as 1,4-phenylene oxide) is combined, and a blend in which a polycarbonate having a positive optical anisotropy and a polycarbonate having a negative optical anisotropy are combined are preferable. In the former case, the ratio of the polystyrene is
Preferably, it accounts for 67% by weight to 75% by weight. In the latter case, it is preferable to use a mixture of a polycarbonate containing bisphenol A having a positive optical anisotropy as a diol component and a polycarbonate mainly containing a fluorene skeleton containing bisphenolfluorene as a diol component. The content of the bisphenol fluorene component in the whole blend is preferably 30 to 90 mol%.

Examples of the copolymer include poly (butadiene-co-polystyrene), poly (ethylene-co-polystyrene), poly (acrylonitrile-co-butadiene), and poly (acrylonitrile-co-butadiene-co-poly).
Styrene), a polycarbonate copolymer, a polyester copolymer, a polyester carbonate copolymer, a polyarylate copolymer, and the like. In particular, since a segment having a fluorene skeleton can have negative optical anisotropy, a polycarbonate copolymer, a polyester copolymer, a polyester carbonate copolymer, a polyarylate copolymer, or the like having a fluorene skeleton is more preferably used.

The polymer material may be a blend of two or more copolymers, a blend of one or more copolymers and the above-mentioned blend or another polymer, or a mixture of two or more copolymers. It may be a blend, a copolymer or a blend of other polymers described above. In these cases,
The content of the bisphenol fluorene component in the whole is preferably 30 to 90 mol%.

A polycarbonate copolymer produced by reacting a bisphenol with a phosgene or a carbonate-forming compound such as diphenyl carbonate is excellent in transparency, heat resistance and productivity, and can be particularly preferably used. The polycarbonate copolymer is preferably a copolymer containing a structure having a fluorene skeleton.
The component having a fluorene skeleton is a repeating unit represented by the formula (I), and preferably contains 1 to 99 mol% of the entire repeating unit.

Specifically, the following formula (I)

[0059]

Embedded image

(In the above formula (I), R _{1 to} R ₈ are each independently at least one selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 6 carbon atoms, and X is

[0061]

Embedded image

Is as follows. ) Is 30.
~ 90 mol% and the following formula (II)

[0063]

Embedded image

(In the above formula (II), R _{9 to} R ₁₆ each independently represent a hydrogen atom, a halogen atom and a carbon atom having 1 to 2 carbon atoms.
At least one selected from the group consisting of
Is the following formula group

[0065]

Embedded image

(Here, R _{17 to} R ₁₉ , R ₂₁ and R in Y
₂₂ is each independently selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 22 carbon atoms, R ₂₀ and R ₂₃ are each independently selected from a hydrocarbon group having 1 to 20 carbon atoms, and Ar is It is at least one group selected from 10 aryl groups. )) Represents 70 units in total.
Polycarbonate copolymers occupying 10 to 10 mol% are exemplified.

In the above formula (I), R _{1 to} R ₈ are each independently selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 6 carbon atoms. Examples of such a hydrocarbon group having 1 to 6 carbon atoms include an alkyl group such as a methyl group, an ethyl group, an isopropyl group and a cyclohexyl group, and an aryl group such as a phenyl group. Of these, a hydrogen atom and a methyl group are preferred.

In the above formula (II), R _{9 to} R ₁₆ are each independently selected from a hydrogen atom, a halon atom and a hydrocarbon group having 1 to 22 carbon atoms. Examples of the hydrocarbon group having 1 to 22 carbon atoms include an alkyl group having 1 to 9 carbon atoms such as a methyl group, an ethyl group, an isopropyl group and a cyclohexyl group, and an aryl group such as a phenyl group, a biphenyl group and a terphenyl group. Can be Of these, a hydrogen atom and a methyl group are preferred.

In Y of the above formula (II), R _{17 to} R ₁₉ ,
R ₂₁ and R ₂₂ are each independently at least one group selected from a hydrogen atom, a halogen atom and a hydrocarbon group having 1 to 22 carbon atoms. Examples of the hydrocarbon group include the same as those described above. R ₂₀ and R ₂₃
Are each independently selected from hydrocarbon groups having 1 to 20 carbon atoms, and examples of such hydrocarbon groups are the same as those described above. Ar is an aryl group having 6 to 10 carbon atoms such as a phenyl group and a naphthyl group.

The polymer oriented film in the present invention is preferably one using a polycarbonate having a fluorene skeleton. As the polycarbonate having a fluorene skeleton, for example, a polycarbonate copolymer comprising a repeating unit represented by the above formula (I) and a repeating unit represented by the above formula (II), a repeating unit represented by the above formula (I) And the above formula (I
A blend with a polycarbonate comprising a repeating unit represented by I) is preferable. The content of the above formula (I), that is, the copolymer composition in the case of a copolymer and the blend composition ratio in the case of a blend, is 30 to 30% of the entire polycarbonate. 90 mol% is preferred. If the ratio is out of the range, it is difficult to uniformly obtain a retardation film having a small retardation value. The content of the above formula (I) is preferably 35 to 85 mol% of the whole polycarbonate, and 50 to 80 mol%.
Is more preferred.

The above-mentioned copolymers have the formulas (I) and (I)
Two or more kinds of repeating units represented by I) may be combined, and in the case of a blend, two or more kinds of the above repeating units may be combined.

Here, the above molar ratio can be determined by, for example, a nuclear magnetic resonance (NMR) apparatus for the entire polycarbonate bulk constituting the oriented polymer film regardless of the copolymer or the blend.

The polycarbonate having a fluorene skeleton is represented by the following formula (III):

[0074]

Embedded image

(In the above formula (III), R ₂₄ and R ₂₅
Is independently at least one selected from a hydrogen atom and a methyl group. 3)
5 to 85 mol%, and the following formula (IV)

[0076]

Embedded image

(In the above formula (IV), R ₂₆ and R ₂₇ are each independently selected from a hydrogen atom and a methyl group, and Z is a group represented by the following formula:

[0078]

Embedded image

At least one group selected from It is particularly preferable to use a polycarbonate copolymer and / or a blend of which 65 to 15 mol% of the total amount is used.

The above-mentioned copolymer and / or blend can be produced by a known method. Polycarbonate is a method by polycondensation of a dihydroxy compound and phosgene,
A melt polycondensation method or the like is preferably used. In the case of a blend, a compatible blend is preferable, but even if they are not completely compatible, if the refractive index between the components is matched, light scattering between the components is suppressed,
It is possible to improve the transparency.

The limiting viscosity of the above polycarbonate is 0.3
Preferably it is ~ 2.0 dl / g. If it is less than 0.3, there is a problem that it becomes brittle and cannot maintain mechanical strength.
If it exceeds 3.0, the solution viscosity becomes too high, which causes problems such as generation of die lines in solution film formation and difficulty in purification at the end of polymerization.

The polymer oriented film constituting the retardation film is preferably transparent, the haze value is preferably 3% or less, and the total light transmittance is preferably 85% or more.

Further, ultraviolet absorbers such as phenylsalicylic acid, 2-hydroxybenzophenone and triphenyl phosphate, bluing agents for changing color,
An antioxidant and the like may be added.

The retardation film of the present invention is composed of a polymer oriented film obtained by stretching an unstretched film such as the above polycarbonate or the like to orient the polymer chains. As a method for producing such a film, a known melt extrusion method, a solution casting method, or the like is used, and a solution casting method is more preferably used from the viewpoints of uneven film thickness and appearance. As the solvent in the solution casting method, methylene chloride, dioxolane or the like is preferably used.

The stretching method may be a known stretching method, but is preferably longitudinal uniaxial stretching. In the film, for the purpose of improving the stretchability, known plasticizers such as dimethyl phthalate, diethyl phthalate, phthalate esters such as dibutyl phthalate, phosphate esters such as tributyl phosphate, aliphatic dibasic esters, glycerin derivatives, A glycol derivative or the like may be contained. At the time of stretching, the organic solvent used at the time of film formation described above may be left in the film and stretched. The amount of the organic solvent is preferably 1 to 20% by weight based on the solid content of the polymer.

The above-mentioned additives such as plasticizer and liquid crystal can change the retardation wavelength dispersion of the retardation film of the present invention, but the amount of addition is preferably 10% by weight or less, and more preferably 3% by weight or less based on the solid content of the polymer. Is more preferred. In particular, the liquid crystal as an additive can greatly change the wavelength dispersion of retardation, but in the present invention, the liquid crystal may not be used.

The thickness of the retardation film is not limited, but is preferably 1 μm to 400 μm. In the present invention, the term “retardation film” is used, but it is commonly referred to as “film” or “sheet”.
It is meant to include any of the above.

As described above, in order to decrease the retardation of the retardation film as the wavelength becomes shorter, the chemical structure of the polymer constituting the polymer oriented film is important, and the wavelength dispersion of the retardation is considerably large. It should be noted that although it is determined by its chemical structure, it also varies depending on film forming conditions, additives, stretching conditions, blend state, molecular weight and the like.

As one aspect of the present invention, the antireflection film of the present invention can further be laminated with one or more other retardation films satisfying the above formula (1). Specifically, an antireflection film using a λ / 4 plate as the retardation film, using a λ / 2 plate as such another retardation film, and laminating them is preferable. (A retardation film in which such a λ / 4 plate and a λ / 2 plate are laminated may be referred to as a laminated retardation film.) In this case, both the λ / 4 plate and the λ / 2 plate have the following formula ( 10)
(11)

[0090]

It is preferable that 0.6 <R (450) / R (550) <1 (10) 1 <R (650) / R (550) <1.4 (11)

By laminating such a λ / 4 plate and a λ / 2 plate, when linearly polarized light is incident on the laminated retardation film, any wavelength of 400 to 700 nm, preferably 400 to 780 nm of the measurement wavelength is measured. But almost perfect circular polarization,
Conversely, when perfect circularly polarized light is incident on the laminated retardation film, almost perfect linearly polarized light can be obtained at any of the measurement wavelengths of 400 to 700 nm. The prevention characteristics are obtained. In the present invention, sufficient antireflection properties can be obtained even with a single retardation film having retardation wavelength dispersion characteristics as described above, but such a configuration is also used particularly in applications where reflection characteristics are required over a wider band. obtain. If the characteristics as in (1) are not satisfied, it is difficult to obtain very good antireflection characteristics over a wide band.

Further, as for the bonding angle between the λ / 4 plate and the λ / 2 plate, the angle of the optical axis is preferably 50 to 70 degrees, and the λ / 4 plate and the λ / 2 plate are made of the same material. , But may be different. The optical axis referred to here is a fast axis or a slow axis.

For such another retardation film, the same polymer material as described above for the retardation film can be used. In particular, the values of R (450) / R (550) and R (650) / R (550) are λ / 4 plate and λ / 2
It is preferably the same for the plate.

The antireflection film of the present invention comprises a combination of the above retardation film and a polarizing plate. It is preferable that the polarizing plate and the retardation film are in close contact with each other, and the polarizing plate and the retardation film can be bonded to each other via an adhesive. As the pressure-sensitive adhesive, a known pressure-sensitive adhesive can be used, but in order to reduce interface reflection, it is more preferable to select a pressure-sensitive adhesive having an intermediate refractive index between the polarizing plate and the retardation film. The angle between the slow axis or fast axis of the retardation film and the polarizing axis of the polarizing plate is preferably 45 degrees. Known polarizing plates such as iodine-based and dye-based polarizing plates can be used.

As a material of the substrate 7 in FIG. 2, a glass substrate is usually used, but a material made of a polymer material may be used. When a polymer material is used, a barrier layer such as a gas barrier layer or a water vapor barrier layer may be provided on the substrate. As the barrier layer, a curable resin layer, a metal oxide layer, or the like can be used.

In the combination of the light emitting element as shown in FIG. 2 and the antireflection film of the present invention, the light emitting element is
In the case of such a configuration, it is also possible to use the substrate of 7 as 14 retardation films. In such a case, since the substrate 7 is not required, a cost advantage can be obtained by reducing the weight and reducing the number of members. However, in this case, if deterioration of the light emitting element becomes a problem, a gas barrier layer, a water vapor barrier layer, or the like may be provided on the retardation film in order to prevent them. Even in these cases, the combination of the polarizing plate and the retardation film exhibits an antireflection function, that is, it is possible to provide an antireflection film that also serves as a substrate of a light emitting element.

It is known that a retardation film generally gives a different retardation value to obliquely incident light as compared with front incident light. Since the antireflection film of the present invention is composed of a circularly polarizing plate, this indicates that the antireflection effect for obliquely incident light is inferior. However, as a result of intensive studies on this problem, it was found that such a problem can be avoided by controlling the three-dimensional refractive index of the retardation film. Here, the three-dimensional refractive index of the retardation film is n
It is expressed by x, ny, and nz, and each definition is nx: the refractive index in the main stretching direction in the plane of the retardation film ny: the refractive index in the direction orthogonal to the main stretching direction in the plane of the retardation film It is the refractive index in the normal direction of the film surface. Here, the main stretching direction, the stretching direction when the retardation film is uniaxially stretched polymer oriented film,
In the case of biaxial stretching, it means a direction in which the degree of orientation is further increased, and in chemical structure, it refers to the direction of orientation of the polymer main chain. Here, when nx> nz, the optical anisotropy is positive and n
When x <nz, the optical anisotropy is called negative. The three-dimensional refractive index is measured by an ellipsometry, which is a technique for analyzing the polarization state of outgoing light obtained by inputting polarized light to a retardation plate. In the present invention, the optical anisotropy of the retardation plate is determined. The three-dimensional refractive index is determined by a method of determining the refractive index ellipsoid by using a known refractive index ellipsoidal formula assuming the refractive index ellipsoid. Since the three-dimensional refractive index depends on the wavelength of the light source used, it is preferable to define the three-dimensional refractive index with the wavelength of the light source used. As a method of expressing optical anisotropy using the three-dimensional refractive index, the following formula (6) is used.

[0098]

Nz = (nx−nz) / (nx−ny) (6), but if this is used to define a three-dimensional refractive index, Nz is in the range of 0.3 to 1.5. In some cases, the incident angle dependence of the phase difference value is very small, which is preferable. More preferably, Nz is from 0.4 to 1.1, but especially when Nz = 0.5, the incident angle dependency of the phase difference value is substantially eliminated, and the same phase difference value is obtained regardless of the angle at which light enters. It is particularly preferred because it gives.

According to the above definition, the retardation film of the positive optical anisotropy has a nx slow axis and a ny fast axis.

Further, the antireflection film of the present invention is provided with a known antireflection film made of a multilayer film or the like, or a so-called antireflection film having irregularities on its surface, for the purpose of antireflection on the polarizing plate surface. Those subjected to anti-glare treatment or the like may be used. Further, similarly, a contamination prevention layer may be provided.

By providing such an antireflection film on the light emitting surface side of the light emitting element and the retardation film on the light emitting layer side of the light emitting element, a display element with good visibility even in the presence of external light is provided. can do.

In the organic electroluminescent device, a metal electrode is provided on the back side of the light emitting layer as shown in FIG. In this device, it is necessary to manufacture each layer as a flat film for high performance. As a result, the metal electrode is designed to be extremely flat like a mirror surface and not to cause irregular reflection. Therefore, in the presence of external light, external light is reflected by the metal electrode, and visibility is reduced. The antireflection film of the present invention can prevent such external light reflection in a wide wavelength range. Known layers can be used for each layer of the organic electroluminescent element.

[0103]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the present invention is limited thereto.

(Evaluation Method) The material characteristic values and the like described in this specification were obtained by the following evaluation methods. (1) Measurement of phase difference value (R = Δn · d (nm)) and Nz The phase difference R value and Nz, which are the product of the birefringence Δn and the film thickness d, are measured using a spectroscopic ellipsometer “M150” (JASCO Corporation) Manufactured). The R value was measured with the incident light and the film surface orthogonal to each other. Also, the Nz value is a three-dimensional refractive index nx by changing the angle between the incident light beam and the film surface, measuring the phase difference value at each angle, and performing curve fitting with a known refractive index ellipsoidal equation. , ny, nz were obtained and substituted into the following equation (6). In this case, an average refractive index n = (nx + ny + nz) / 3 is required as another parameter, which is an Abbe refractometer (trade name “Abe refractometer 2- by Atago Co., Ltd.”). T ”.

[0105]

Nz = (nx−nz) / (nx−ny) (6)

(2) Organic Electroluminescent Device Evaluation System An organic electroluminescent device emitting green light was produced as follows.
The configuration is shown in FIG. First, a 0.7 mm thick glass substrate 2
2 on a transparent electrode ITO (I
ndium Tin Oxide) film. Next, TPD (N, N'-bis (3-methylphenyl) 1,1'-biphenyl-4,4'-diamine), which is a triphenyldiamine derivative, is formed on the ITO film as a hole transport layer 24 by a vacuum evaporation method. 50
nm. Next, Alq3 (tris-
(8-Hydroxyquinoline) aluminum) was deposited to a thickness of 50 nm. This light emitting layer also serves as the electron transport layer 11 in FIG. In addition, magnesium and silver are further
To form a metal electrode 26. When a voltage was applied to the light-emitting device, green light emission was confirmed.

The main object of the present invention is to suppress the reflection prevention of the light emitting device by a simple method in a wide wavelength range. Therefore, in the following Examples and Comparative Examples, the substrate of the organic electroluminescent device is provided with: As shown in FIG. 7, in the state where the anti-reflection film of the present invention is adhered through an adhesive, the degree of reduction of external light reflection is particularly observed.

To see the degree of reduction in external light reflection,
Evaluation was performed by performing regular reflection measurement at 5 degrees using a spectrophotometer "U-3500" (manufactured by Hitachi, Ltd.). At this time, a blank using only the polarizing plate 20 without using the retardation film 21 on the substrate of the organic electroluminescent device was used as a blank. The measurement is performed by setting the reflectance at each wavelength to 100%. An antireflection layer made of a multilayer film having a different refractive index is provided on the polarizing plate. As this polarizing plate, “LLC2-9218” (manufactured by Sanritz) was used. In the reflectance measurement, measurement is performed in a state where no voltage is applied.

In Table 2, I (λ) indicates the reflected light intensity at the wavelength λ (nm), and Nz (λ) indicates the Nz at the wavelength λ.
It is.

(3) Measurement of Water Absorption Measured in accordance with “Test Method for Water Absorption and Boiling Water Absorption of Plastics” described in JIS K 7209, except that the thickness of the dried film was changed to 130 ± 50 μm. did. The size of the test piece was 50 mm square, and the sample was immersed in water at 25 ° C. for 24 hours, and then the weight change was measured. The unit is%.

(4) Measurement of Glass Transition Temperature (Tg) of Polymer The polymer was measured by "DSC2920 Modulated DSC" (manufactured by TA Instruments). Not after film molding, but after resin polymerization,
Measured in flake or chip condition.

(5) Film thickness measurement The film thickness was measured using an electronic micro manufactured by Anritsu Corporation.

(6) Measurement of Polymer Copolymerization Ratio It was measured by proton NMR of “JNM-alpha600” (manufactured by JEOL Ltd.). In particular, in the case of a copolymer of bisphenol A and biscresol fluorene, heavy benzene was used as a solvent, and calculation was performed from the proton intensity ratio of each methyl group.

The monomer structures of the polycarbonates used in the following Examples and Comparative Examples are described below.

[0115]

Embedded image

Example 1 An aqueous sodium hydroxide solution and ion-exchanged water were charged into a reaction vessel equipped with a stirrer, a thermometer and a reflux condenser, and the monomer [A] having the above structure was added thereto.
And [F] were dissolved in the molar ratio shown in Table 2, and a small amount of hydrosulfite was added. Next, methylene chloride was added thereto, and 2
At 0 ° C., phosgene was blown in for about 60 minutes. further,
After adding and emulsifying p-tert-butylphenol, triethylamine was added and the mixture was stirred at 30 ° C. for about 3 hours to terminate the reaction. After completion of the reaction, the organic phase was separated and methylene chloride was evaporated to obtain a polycarbonate copolymer. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio.

This copolymer was dissolved in methylene chloride to prepare a dope solution having a solid content of 20% by weight.
A cast film was prepared from this dope solution,
The film was uniaxially stretched twice at 30 ° C. to obtain a retardation plate.

Table 2 summarizes the measurement results. In this film, it was confirmed that the shorter the measurement wavelength was, the smaller the phase difference was, and the refractive index anisotropy was positive.

An adhesive was applied so that the slow axis of the retardation film and the polarizing axis of the polarizing plate were at 45 degrees, and the light emitting element was attached via the adhesive as shown in FIG.

FIG. 1 shows a reflection spectrum of the organic electroluminescent device when no voltage is applied. It was found that the reflectance was low over a wide band of wavelengths, and good black display was possible even in the presence of external light when no voltage was applied.

Example 2 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 2 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and uniaxially stretched at a temperature of 230 ° C. twice to obtain a retardation plate. Table 2 summarizes the measurement results. In this film, it was confirmed that the shorter the measurement wavelength was, the smaller the phase difference was, and the refractive index anisotropy was positive. It has been found that the organic electroluminescent device has a low reflectance over a wide band of wavelengths, and enables good black display even in the presence of external light when no voltage is applied.

Example 3 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 2 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 2, a film was formed and uniaxially stretched at a temperature of 200 ° C. 1.9 times to obtain a retardation plate. Table 2
The measurement results are summarized below. In this film, it was confirmed that the shorter the measurement wavelength was, the smaller the phase difference was, and the refractive index anisotropy was positive. It has been found that the organic electroluminescent device has a low reflectance over a wide band of wavelengths, and enables good black display even in the presence of external light when no voltage is applied.

Example 4 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 2 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and uniaxially stretched at a temperature of 240 ° C. twice to obtain a retardation plate. Table 2 summarizes the measurement results. In this film, it was confirmed that the shorter the measurement wavelength was, the smaller the phase difference was, and the refractive index anisotropy was positive. It has been found that the organic electroluminescent device has a low reflectance over a wide band of wavelengths, and enables good black display even in the presence of external light when no voltage is applied.

Example 5 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 2 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and uniaxially stretched at a temperature of 250 ° C. and 1.9 times to obtain a retardation plate. Table 2
The measurement results are summarized below. In this film, it was confirmed that the shorter the measurement wavelength was, the smaller the phase difference was, and the refractive index anisotropy was positive.

It has been found that the organic electroluminescent device has a low reflectance over a wide band of wavelengths, and that good black display can be achieved even when external light is present in a state where no voltage is applied.

Example 6 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 2 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and uniaxially stretched at a temperature of 230 ° C. 2.2 times to obtain a retardation plate. Table 2
The measurement results are summarized below. In this film, it was confirmed that the shorter the measurement wavelength was, the smaller the phase difference was, and the refractive index anisotropy was positive.

It has been found that the organic electroluminescent device has a low reflectance over a wide band of wavelengths, and that good black display can be achieved even when external light is present in a state where no voltage is applied.

[0128]

[Table 2]

[Example 7] Polystyrene (obtained from Wako Pure Chemical Industries, Ltd.) as a polymer having a negative refractive index anisotropy, and polyphenylene oxide (poly ( 2,6-dimethyl 1,4-
(Phenylene oxide) obtained from Wako Pure Chemical Industries, Ltd.)
Was dissolved in chloroform at a ratio of 70 and 30% by weight, respectively, to prepare a dope solution having a solid content of 18% by weight. A cast film was prepared from this dope solution,
The film was uniaxially stretched three times at a temperature of three times. The glass transition temperature of this film was 125 ° C.

Table 3 summarizes the results of measuring the optical characteristics. In this film, it was confirmed that the shorter the measurement wavelength, the smaller the phase difference and the negative the refractive index anisotropy.

It was found that the organic electroluminescent device has a low reflectance over a wide band of wavelengths, and that good black display can be achieved even when external light is present in a state where no voltage is applied.

For reference, FIG. 8 shows the relationship between the birefringence wavelength dispersion coefficient and the volume fraction of polyphenylene oxide when the blend ratio of polystyrene and polyphenylene oxide was changed. In the region where the amount of polyphenylene oxide is small, the optical anisotropy is negative and the birefringence wavelength dispersion coefficient is 1
It can be seen that there is a smaller area. On the other hand, the value is larger than 1 in a region where the refractive index anisotropy is large in which polyphenylene oxide is large.

Next, the relationship between the volume fraction and the birefringence chromatic dispersion coefficient as shown in FIG. 8 calculated using the above-mentioned equation (c) is shown.
Write it in 7. FIG. 9 shows the intrinsic birefringence of polystyrene and polyphenylene oxide at a wavelength of 550 nm, respectively, of -0.1.
10, 0.21 (D. Lefebvre, B. Jasse and L. Monnerie, Po
lymer 23 706-709 (1982)). It can be said that the agreement between FIG. 8 and FIG. 9 is good. The densities of polystyrene and polyphenylene oxide are 1.047 and 1.060 g, respectively.
/ Cm ³ .

[0134]

[Table 3]

Comparative Example 1 A polycarbonate homopolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained homopolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and stretched at a temperature of 160 ° C. and 1.1 times to obtain a retardation plate. Table 4 summarizes the measurement results. In this film, it was confirmed that the shorter the measurement wavelength, the larger the absolute value of the retardation.

The film was evaluated as an organic electroluminescent device by using this film. The reflection of light was large on the long wavelength side and the short wavelength side, and the appearance was purple when no voltage was applied in the presence of external light. And it was found that the display element had poor display quality. FIG. 1 shows the reflectance spectral characteristics of this element.

Comparative Example 2 A polycarbonate homopolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained homopolymer was almost the same as the monomer charge ratio. A film was formed and stretched at a temperature of 245 ° C. 2.0 times in the same manner as in Example 1 to obtain a retardation plate. Table 4 summarizes the measurement results. This film was found to be unsuitable as a retardation film for an anti-reflection film of the present invention because the shorter the measurement wavelength, the larger the absolute value of the retardation in the absolute value.

Comparative Example 3 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and stretched at a temperature of 180 ° C. 1.1 times to obtain a retardation plate. Table 4 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 4 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and stretched at a temperature of 240 ° C. 1.9 times to obtain a retardation plate. Table 4 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 5 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and stretched at a temperature of 190 ° C. 1.1 times to obtain a retardation plate. Table 4 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 6 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and stretched at a temperature of 240 ° C. 1.2 times to obtain a retardation plate. Table 4 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 7 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 4 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. A film was formed and stretched at a temperature of 200 ° C. 1.2 times in the same manner as in Example 1 to obtain a retardation plate. Table 4 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

[0143]

[Table 4]

Comparative Example 8 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 5 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. A film was formed and stretched at a temperature of 240 ° C. 1.5 times in the same manner as in Example 1 to obtain a retardation plate. Table 5 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 9 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 5 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. In the same manner as in Example 1, a film was formed and stretched at a temperature of 240 ° C. 1.8 times to obtain a retardation plate. Table 5 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 10 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 5 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. Film formation as in Example 1,
The film was stretched at a temperature of 240 ° C. 1.8 times to obtain a retardation plate. Table 5 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

Comparative Example 11 A polycarbonate copolymer was obtained in the same manner as in Example 1 except that the monomers shown in Table 5 were used. The composition ratio of the obtained copolymer was almost the same as the monomer charge ratio. Film formation as in Example 1,
The film was stretched at a temperature of 220 ° C. 2.0 times to obtain a retardation plate. Table 5 summarizes the measurement results. It was found that the shorter the wavelength of the film measured, the larger the absolute value of the retardation, and the film was not suitable as the retardation film for an antireflection film of the present invention.

[0148]

[Table 5]

[0149]

As described above, a retardation film made of a polymer such that the retardation value becomes smaller as the wavelength becomes shorter with one sheet, which has not been found in a conventionally used retardation film, is used. By combining with a polarizing plate as a quarter-wave plate of the anti-reflection film, an anti-reflection film having an excellent anti-reflection effect over a wide wavelength range can be provided with high productivity. In addition, by using such an anti-reflection film for a light-emitting element having a high light reflectivity such as a metal electrode incorporated in the element, particularly for an organic electroluminescent element, it has excellent visibility even in the presence of external light. This has the effect that a light emitting element can be provided at low cost.

[Brief description of the drawings]

FIG. 1 is a reflection spectrum of Example 1 and Comparative Example 1 with no voltage applied to an organic electroluminescent device.

FIG. 2 is a schematic view illustrating the principle of an antireflection film in the organic electroluminescent device of the present invention.

FIG. 3 is a graph showing the relationship between the wavelength dispersion of birefringence of a two-component blend polymer and the type and blend ratio of the polymer.

FIG. 4 is a graph showing the relationship between the wavelength dispersion of birefringence of a binary blended polymer, the type of polymer, and the blend ratio.

FIG. 5 is a graph showing the relationship between the wavelength dispersion of birefringence of a binary blended polymer and the type and blend ratio of the polymer.

FIG. 6 is a graph showing the relationship between the wavelength dispersion of birefringence of a two-component blended polymer and the type and blend ratio of the polymer.

FIG. 7 is a schematic view of an organic electroluminescent device in Examples and Comparative Examples.

FIG. 8 is a graph showing a relationship between a birefringence wavelength dispersion coefficient of a retardation film and a volume fraction of a polymer component in Example 7.

FIG. 9 is a graph showing the relationship between the birefringence wavelength dispersion coefficient of the retardation film and the volume fraction of the polymer component in Example 7.

[Explanation of symbols]

1; external light 2; linearly polarized light that has passed through a polarizing plate 3; clockwise (counterclockwise) circularly polarized light that has passed through a retardation film 4; Polarized light 5; linearly polarized light that has passed through the retardation film again and is out of phase by 2 and 180 degrees (can not pass through the polarizing plate 13 and is absorbed here) 6; emitted light 7; transparent substrate 8; Transparent electrode layer (ITO) 9; hole transport layer 10; light emitting layer 11; electron transport layer 12; metal electrode 13; polarizer 14; retardation film (quarter wavelength plate) 15; Film 20; Polarizing plate 21; Retardation film (quarter wavelength plate) 22; Transparent substrate 23; Transparent electrode (ITO) 24; Hole transport layer 25; Emitting layer 26; Metal electrode 27;

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) C08L 71/12 C08L 71/12 5G435 G02B 1/11 G09F 9/00 313 G09F 9/00 313 G02B 1/10 A (72) Inventor Shoichi Tsujikura 4-3-2 Asahigaoka, Hino-shi, Tokyo Teijin Limited, Tokyo Research Center F-term (reference) 2H049 BA02 BA03 BA06 BA07 BA16 BA42 BB03 BB44 BB65 BC03 BC22 2K009 AA01 AA02 AA12 CC21 CC34 DD01 4F071 AA22 AA47 AA50 AF29 AH16 BA01 BB02 BB07 BC01 BC10 4J002 BC031 CH072 GP00 4J029 AA09 AB07 AC02 AD01 AD07 AE03 AE04 BB12A BB12B BB16A BB16B BB16C BD09A BD09B03 B07 BB16B09B07 BB16B13B09B07 FF05

Claims (15)

[Claims] 1. An anti-reflection film comprising a single polymer oriented film and a retardation film having a retardation at wavelengths of 450 nm and 550 nm satisfying the following formula (1): and a polarizing plate. . | R (450) | <| R (550) | (1) (In the above equation (1), | R (450) |, | R (55
0) | is the absolute value (nm) of the in-plane retardation at wavelengths of 450 nm and 550 nm, respectively. ) 2. The antireflection film according to claim 1, wherein the retardation of the retardation film is a quarter wavelength. 3. A retardation film having a wavelength of 450 nm and a wavelength of 55 nm.
The phase difference at 0 nm and 650 nm is expressed by the following equation (2).
And (3) 0.6 <R (450) / R (550) <0.97 (2) 1.01 <R (650) / R (550) <1.4 (3) In the formula (3), R (650) is an in-plane retardation of the polymer oriented film at a wavelength of 650 nm.) 4. The anti-reflection film according to claim 1, wherein the shorter the wavelength, the smaller the retardation of the retardation film at a wavelength of 400 to 700 nm. 5. The anti-reflection film according to claim 2, wherein a retardation film having a retardation of a half wavelength is further laminated. 6. The retardation film having a half-wave retardation and the quarter-wave retardation film have a retardation at wavelengths of 450 nm, 550 nm, and 650 nm, respectively, in accordance with the following formulas (10) and (10). 11) 0.6 <R (450) / R (550) <1 (10) 1 <R (650) / R (550) <1.4 (11) (Equations (10) and (10) The antireflection film according to claim 5, wherein the definition in 11) is the same as described above. 7. A retardation film comprising: (1) a polymer monomer unit having a positive refractive index anisotropy (hereinafter, referred to as a first monomer unit) and a polymer having a negative refractive index anisotropy And (2) a polymer based on the first monomer unit, wherein R (45) is a polymer based on the first monomer unit.
0) / R (550) is smaller than R (450) / R (550) of the polymer based on the second monomer unit, and (3) polymer orientation having positive refractive index anisotropy The anti-reflection film according to any one of claims 1 to 6, comprising a film. 8. The retardation film has (1) a monomer unit forming a polymer having a positive refractive index anisotropy (hereinafter, referred to as a first monomer unit) and a negative refractive index anisotropy. A film comprising a polymer containing a monomer unit forming a polymer (hereinafter, referred to as a second monomer unit); and (2) a polymer R (45) based on the first monomer unit.
0) / R (550) is larger than R (450) / R (550) of the polymer based on the second monomer unit, and (3) a polymer oriented film having negative refractive index anisotropy The antireflection film according to any one of claims 1 to 6, comprising: 9. The antireflection film according to claim 1, wherein the water absorption of the oriented polymer film is 1% by weight or less. 10. The antireflection film according to claim 1, wherein the polymer oriented film contains a polycarbonate having a fluorene skeleton. 11. The polymer having a positive refractive index anisotropy is poly (2,6-dimethyl-1,4-phenylene oxide), and the polymer having a negative refractive index anisotropy is polystyrene. The anti-reflection film according to claim 8, wherein the polystyrene content is 67% by weight to 75% by weight. 12. The antireflection film according to claim 1, wherein the antireflection film is provided on a light emitting side of a light emitting element. 13. A substrate, a transparent electrode,
A light emitting device comprising a hole transport layer, a light emitting layer, an electron transport layer, and a metal electrode layer, wherein the antireflection film according to any one of claims 1 to 12 is provided on the light emission side. Light emitting element. 14. The light emitting device according to claim 13, wherein the retardation film constituting the antireflection film according to claim 1 also serves as a substrate of the light emitting device. 15. The light emitting device according to claim 13, wherein the light emitting device is an organic electroluminescent device.