KR20150101106A - Optical filter for an organic electroluminescence device - Google Patents

Abstract

The present invention relates to an optical filter for lighting of an organic electroluminescence device (OLED) and an OLED lighting including the same. The present invention provides the optical filter for the OLED lighting, which includes: a substrate film, a light diffusing film or an anti-reflective film formed on one surface of the substrate film, and an adhesive layer formed on the other surface of the substrate film; and at least one dye allowing the light diffusing film or the anti-reflective film, the adhesive layer, or both to absorb a specific wavelength band. The optical filter according to the present invention minimizes the loss of brightness while realizing a desired color for the OLED lighting in an off-state, thereby providing a decoration function. In addition, the optical filter can be effectively used as a front optical filter since color purity of light in a luminous state of the lighting can be improved.

Description

[0001] OPTICAL FILTER FOR AN ORGANIC ELECTROLUMINESCENCE DEVICE [0002]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a front optical filter for an organic electroluminescence device (OLED) illumination and an organic electroluminescent device illumination including the front optical filter.

The organic light emitting display (OLED), which is a flat panel display, is a self-luminous display, and can be made lightweight and thinner because it does not require a backlight as compared with a liquid crystal display, which is a non-electroluminescent display.

The OLED can be fabricated as a planar light source, and it can be fabricated as a thin light source with a thickness of about 2.0 mm. There is no need for additional parts such as a luminaire in the process of making a surface light source, and when there is no problem such as efficiency and reduction of color rendering property, it is very advantageous when applied to an indoor lighting requiring a light source. In addition, various colors of R (red), G (green), B (blue), or visible light (full W) can be implemented and applied to various fields such as interior lighting as well as vehicle lighting.

However, in OLED lighting, the reflection of the OLED light itself is large in the off state due to the presence of the metal used as the cathode electrode, so that the OLED illumination can give a mirror-like feeling in the off state.

Accordingly, it has been found that, when an optical filter is applied to the front surface of an OLED illumination, a visual effect can be imparted regardless of on / off when an additional color is given to the illumination even in the off state. .

Accordingly, it is an object of the present invention to provide an OLED lighting device capable of minimizing a luminance loss of OLED lighting while providing a decoration function by implementing desired colors for OLED lighting in an off state, Front optical filter, and OLED illumination comprising the same.

In order to achieve the above object,

A light diffusing film or an antireflection film formed on one side of the base film, and an adhesive layer formed on the other side of the base film,

Wherein the light diffusion film or the antireflection film, the pressure-sensitive adhesive layer, or both include a dye that absorbs a specific wavelength band. The present invention also provides an optical filter for an organic electroluminescence (OLED) illumination.

The present invention also provides organic electroluminescent (OLED) illumination comprising the optical filter.

The optical filter according to the present invention is applied to the front surface of an OLED light source to minimize the loss of luminance while providing a desired color for the off-state OLED light to provide a decoration function, And can be usefully used as a front optical filter of OLED illumination.

1 is a cross-sectional view of an optical filter according to the present invention.
2 is a cross-sectional view showing an example in which an optical filter according to the present invention is laminated on a light emitting unit of an illumination.
3 to 5 are graphs showing transmission characteristics (bare Red / Green / Blue before adhering to the organic electroluminescent device illumination, after red / green / blue after attaching) of each of the optical filters prepared in Examples 1 to 3, And FIG. 5 is a graph showing changes in the light emission intensity of each of the organic electroluminescent device lights to which the filter is applied.

The optical filter for OLED illumination of the present invention

(1) a base film;

(2) a light diffusion film or an antireflection film formed on one side of the base film; And

(3) an adhesive layer formed on the other surface of the substrate film,

The light diffusion film or the antireflection film, the pressure sensitive adhesive layer, or both include a dye absorbing a specific wavelength band, and may further include a UV blocking agent, if necessary.

By adjusting the transmission spectrum of the optical filter, the present invention suppresses the metal reflection caused by the external light of the OLED illumination in the off state and allows the OLED illumination to have a unique color in the off state. That is, the color of the optical filter attached to the front of the OLED illumination may be the same as the color of the light source of the OLED illumination.

Specific examples of the dyes include PM, pyrrol methin, RH, Rhodamine, BODIPY, boron dipyrromethene, Azo, azo compound, Coumarin, Dyes such as dyes that absorb (shield) wavelengths below 510 nm; Dyes that absorb wavelengths from 560 to 580 nm, such as tetraaza porphyrin (TAP), rhodamine (RH), squaraine (SQ), and cyanine (CY) cyanine dyes; Dyes that absorb wavelengths of 600 nm or more, such as phthalocyanine (PC, phthalocyanine) dyes; And a dye absorbing a visible light region (380 to 780 nm) such as carbon black (CB) dyes uniformly. In order to absorb a desired wavelength band depending on the color of a light source, The combination of dyes above can be selected.

For example, in the case of an OLED illumination using a blue light source, one or more dyes may be used such that the main absorption wavelength band is 500 nm or more, preferably 500 nm to 780 nm.

In the case of OLED illumination using a green light source, one or more dyes may be used that have a main absorption wavelength band of 480 nm or less and / or a main absorption wavelength band of 580 nm or more. In this case, the wavelength band of 480 nm or less may be 380 nm to 480 nm, and the wavelength band of 580 nm or more may be 580 nm to 780 nm.

In the case of OLED illumination using a Red light source, one or more dyes may be used, such that the main absorption wavelength band is 600 nm or less, preferably 380 nm to 600 nm.

Preferably, for OLED illumination using a blue light source, a wavelength of at least 500 nm can be predominantly absorbed by using a combination of an azo compound dye, a tetraazaporphyrin (TAP) dye and a phthalocyanine (PC) dye.

OLED illumination using a green light source can mainly absorb wavelengths below 480 nm and / or 580 nm by using a combination of azo compound dyes, coumarin dyes and rhodamine dyes.

For OLED illumination using a Red light source, a combination of azo compound dye, rhodamine dye and tetraaza porphyrin (TAP) dye can be used to mainly absorb wavelengths below 600 nm.

The light-diffusing film or the antireflection film may contain the one or more dyes in an amount of 0.01 to 10% by weight, preferably 0.2 to 7% by weight, based on the total weight of the film. The adhesive layer may contain the one or more dyes in an amount of 0.01 to 10% by weight, preferably 0.2 to 7% by weight, based on the total weight of the adhesive layer.

Further, the light diffusion film or the antireflection film, the pressure-sensitive adhesive layer, or both may further include an ultraviolet screening agent for blocking UV light. The ultraviolet screening agent used is one which absorbs (shields) light of 420 nm or less and is composed of hydroxybenzotriazole (HB), tris-resorcinol-triazine chromophore (TRTC) ), Or a hydroxyphenyl-benzotriazole chromophore (HBC) dye, and they may be used singly or in combination of two or more.

The light diffusion film or the antireflection film may contain the ultraviolet ray blocking agent in an amount of 0.01 to 10% by weight, preferably 0.1 to 6% by weight based on the total weight of the film. The adhesive layer may contain the ultraviolet ray blocking agent in an amount of 0.01 to 10% by weight, preferably 0.1 to 6% by weight based on the total weight of the adhesive layer.

(1)

The base film may be a transparent plastic plastic substrate. Preferably, the base film should be excellent in adhesion to a resin, transmittance of light incident from the rear surface should be 90% or more, flatness of the surface is uniform, Should not.

Specific examples of suitable materials for the base film include polyethylene terephthalate (PET), cellulose triacetate (TAC), polycarbonate (PC), polyether sulfone (PES), polyacrylate (PAR) Polyetherimide (PEI), polyethylene naphthalate (PEN), polyphenylene sulfide (PPS), polyallylate, polyimide, cellulose acetate propionate (PET), cellulose triacetate (TAC), or polycarbonate (PC) can be used.

The thickness of the base film may be 38 to 250 mu m, preferably 38 to 125 mu m.

(2) Light diffusion film or antireflection film

The optical filter of the present invention comprises a light diffusion film or an antireflection film on one side of the base film.

In the case of a light-diffusing film, it is possible to diffuse, refract and scatter light in various angles and directions to subdivide it, to induce irregular diffuse reflection, and to impart gloss to the film. On the other hand, in the case of the antireflection film, the antireflection film serves to reduce the diffuse reflection to reduce the haze and to provide a high light transmittance, and also to function as a hard coating layer for increasing the surface hardness of the base film to prevent scratches on the surface .

The light diffusion film or the antireflection film may be made of a resin such as thermoplastic resin, thermosetting resin, ionizing radiation (ultraviolet ray or electron beam) curing resin, or the like.

Specific examples of the thermoplastic resin and the thermosetting resin include a polyester resin, an acrylic resin, an acrylic urethane resin, a polyester acrylate resin, a polyurethane acrylate resin, an epoxy acrylate resin, a urethane resin, an epoxy resin, a poly Based resin, a melamine-based resin, a phenol-based resin, a silicone-based resin, and a mixture thereof, and the like can be given.

As the ionizing radiation curable resin, a photopolymerizable prepolymer which is crosslinked and cured by irradiation with ionizing radiation can be used. Examples of the photopolymerizable prepolymer include a cationic polymerization prepolymer and a radical polymerization prepolymer. Examples of the cationic polymerization type photopolymerizable prepolymer include epoxy resins and vinyl ether resins. Examples of the epoxy resins include bisphenol-based epoxy resins, novolak-type epoxy resins, alicyclic epoxy resins, aliphatic epoxy resins, And the like. As the radically polymerizable photopolymerizable prepolymer, an acrylic prepolymer (hard prepolymer) having two or more acryloyl groups in one molecule and having a three-dimensional network structure through crosslinking curing can be used particularly preferably from the viewpoint of hard coatability. Examples of the acrylic type prepolymer include urethane acrylate, polyester acrylate, epoxy acrylate, melamine acrylate, polyfluoroalkyl acrylate, silicone acrylate, and mixtures thereof.

At this time, the light diffusion film includes inorganic particles such as titanium oxide, and may further include a filler as required. The filler may be an organic polymeric filler comprising a material selected from the group consisting of light acrylate, polystyrene, nylon, soft acrylate, and silicone. The inorganic particles may have an average particle diameter of 0.01 to 10 mu m, 0.05 to 5 mu m, 0.1 to 1 mu m and 0.3 to 0.5 mu m, and the filler may have an average particle diameter of 0.5 to 5 mu m, preferably 0.8 to 3 mu m have.

On the other hand, the antireflection film includes a photopolymerizable monomer and / or a photopolymerization initiator for imparting various performances such as improvement of crosslinking curability or adjustment of curing shrinkage.

Examples of the photopolymerizable monomer include monofunctional acrylic monomers (e.g., 2-ethylhexyl acrylate, 2-hydroxyethyl acrylate, 2-hydroxypropyl acrylate, butoxyethyl acrylate, etc.), bifunctional acrylic monomers For example, 1,6-hexanediol diacrylate, neopentyl glycol acrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, hydroxypivalic acid ester neopentyl glycol diacrylate, etc.), trifunctional or higher acryl And monomers (e.g., dipentaerythritol hexaacrylate, trimethyl propane triacrylate, pentaerythritol triacrylate, etc.). Examples of the photopolymerization initiator include at least one photoinitiator such as oxime ester, acetophenone, benzophenone, benzoin, and benzoyl, xanthone, triazine, halomethyloxadiazole and ropin .

The light-diffusing film and the antireflection film may contain further additives as necessary insofar as the effect of the present invention is not impaired.

The light diffusion film and the antireflection film may be dry-coated or wet-coated on one side of the substrate film, or may be formed on the other side of the substrate film using an adhesive after being made into a film on a separate support.

The thickness of the light diffusion film and the antireflection film may be 50 to 200 nm, preferably 80 to 120 nm.

(3) Adhesive layer

The optical filter of the present invention comprises an adhesive layer on the other surface of the base film.

The adhesive layer includes a pressure-sensitive adhesive (PSA) and serves to adhere and fix the optical filter to the light-emitting unit of the OLED illumination.

Examples of the pressure-sensitive adhesive or adhesive constituting the pressure-sensitive adhesive layer include pressure-sensitive adhesives or adhesives such as acryl-based, urethane-based, epoxy-based and silicone-based adhesives, and preferably acrylic pressure-sensitive adhesives or adhesives.

The pressure-sensitive adhesive layer may contain further additives as necessary insofar as the effect of the present invention is not impaired.

The adhesive layer may be formed by wet coating on the other surface of the base film.

The thickness of the adhesive layer may be 5 to 100 占 퐉, preferably 15 to 25 占 퐉.

A sectional view of the optical filter according to the present invention having such a structure is shown in Fig. 1, an optical filter 100 according to the present invention includes a light diffusion film or an antireflection film 101, a base film 102, and an adhesive layer 103 in a laminated manner.

The present invention provides an organic electroluminescent device illumination including the optical filter on the front surface. That is, the optical filter of the present invention can be attached to the upper transparent substrate of the light emitting unit of the organic electroluminescent device illumination through the adhesive layer.

An example of an organic electroluminescent element illumination including an optical filter according to the present invention is shown in Fig. 2, an organic EL device illumination according to an exemplary embodiment of the present invention includes a light diffusion film or an antireflection film 101, a base film 102, an adhesive layer 103, a transparent substrate 201, a positive electrode 202 (EL) layer 203, and a cathode electrode 204 in this order (100: optical filter, 200: light-emitting unit).

The transparent substrate 201, the positive electrode 202, the organic light emitting (EL) layer 203, and the negative electrode 204 may have the same material and thickness as those conventionally used in organic electroluminescent device illumination.

The luminance change of the OLED illumination according to the present invention may vary from 50 to 91%, preferably from 70 to 90% of the light source emission, depending on the light source of the OLED illumination. The optical wavelength band in which the optical filter selectively absorbs and reduces the transmittance may be the same as the main absorption wavelength band of the dye itself or shifted depending on the combination of the dyes used so that the wavelength of the main absorption band of the dye itself May be different.

As described above, the optical filter according to the present invention is applied to the front surface of OLED lighting to provide a decoration function by implementing a desired color with respect to an off-state OLED illumination while minimizing a luminance loss, The color purity can be improved and can be usefully used as a front optical filter of OLED illumination.

Hereinafter, the present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Example 1 (Red OLED illumination)

As a pressure-sensitive adhesive, 30% by weight of Soken No. 1811L and 70% by weight of methyl ethyl ketone (MEK) were mixed to prepare a pressure-sensitive adhesive solution. The pressure-sensitive adhesive solution was then mixed with Tinuvin 312 manufactured by Ciba, SK450, SKK 500, 0.01 part by weight, 0.01 part by weight, 0.01 part by weight, 0.01 part by weight, 0.01 part by weight, and 0.01 part by weight, respectively, based on 100 parts by weight of the above pressure sensitive adhesive solution.

The pressure-sensitive adhesive layer composition was coated on the other surface of a 100 占 퐉 -thick transparent PET substrate film having a light diffusion film having a thickness of 10 占 퐉 on one surface using a gap coater, followed by drying and curing to form an adhesive layer having a thickness of 25 占 퐉 Thereby completing an optical filter.

The obtained optical filter was attached to the entire surface of a commercially available Red organic electroluminescent element illumination through an adhesive layer to produce an organic electroluminescent element illumination including the optical filter on the whole surface.

Example 2 (Green OLED illumination)

As a pressure-sensitive adhesive, 30% by weight of Soken No. 1811L and 70% by weight of methyl ethyl ketone (MEK) were mixed to prepare a pressure-sensitive adhesive solution. Tinuvin 312 of Ciba Co., SK420 of SK Chemicals Co., 0.01, and 0.01 parts by weight, respectively, based on 100 parts by weight of the pressure-sensitive adhesive solution to prepare a pressure-sensitive adhesive layer composition (wavelength band of 480 nm or less and absorption of 580 nm or more).

The pressure-sensitive adhesive layer composition was coated on the other surface of a 100 占 퐉 -thick transparent PET substrate film having a light diffusion film having a thickness of 10 占 퐉 on one surface using a gap coater, followed by drying and curing to form an adhesive layer having a thickness of 25 占 퐉 Thereby completing an optical filter.

The resulting optical filter was attached to the front surface of a commercially available green organic electroluminescent element illumination through an adhesive layer to produce an organic electroluminescent element illumination including the optical filter on the entire surface.

Example 3 (Blue OLED illumination)

A pressure-sensitive adhesive solution was prepared by mixing 30% by weight of Soken No. 1811L and 70% by weight of methyl ethyl ketone (MEK) as a pressure-sensitive adhesive, and then the pressure-sensitive adhesive solution was prepared by adding Tinuvin 312 from Ciba, SK550 from SK Chemicals, SK590 from SK Chemicals, 0.01 part by weight, 0.01 part by weight, 0.01 part by weight and 0.01 part by weight, respectively, based on 100 parts by weight of the above-mentioned pressure sensitive adhesive solution to prepare a pressure-sensitive adhesive layer composition (wavelength band absorption of 500 nm or more).

The pressure-sensitive adhesive layer composition was coated on the other surface of a 100 占 퐉 -thick transparent PET substrate film having a light diffusion film having a thickness of 10 占 퐉 on one surface using a gap coater, followed by drying and curing to form an adhesive layer having a thickness of 25 占 퐉 Thereby completing an optical filter.

The obtained optical filter was attached to the front surface of a commercially available blue organic electroluminescent element illumination through an adhesive layer to produce an organic electroluminescent element illumination including the optical filter on the whole surface.

Comparative Example 1

The Red organic electroluminescent device illumination used in Example 1 was used, but without any filter attached.

Comparative Example 2

Green organic electroluminescent device illumination used in Example 2 was used, but without any filter attached.

Comparative Example 3

The blue organic electroluminescent device illumination used in Example 3 was used, but without any filter attached.

<Experimental Example>

The spectral change and characteristics of the organic electroluminescent device illuminations prepared in Examples and Comparative Examples were measured using a radiometer (CS-2000, Minolta), and the results are shown in Table 1 below .

Further, the transmittance characteristics (bare Red / Green / Blue before attachment to the organic electroluminescent device illumination: red / green / blue after attachment) of each of the optical filters prepared in Examples 1 to 3 and the organic The change in luminescence intensity of each of the electroluminescent device lights is shown in Figs. 3 to 5, respectively.

At this time, the filter transmittance is a change value of intensity before and after attachment of the filter to R, G, and B OLED illumination.

The color coordinates are R (x, y: 0.666, 0.333), G (0.195, 0.735) and B (0.141, 0.046) for the OLED light source and C : 0.671, 0.329), G (0.197, 0.735) and B (0.141, 0.046). It can be seen that this is closer to R (x, y: 0.670, 0.330), G (0.210, 0.710) and B (0.140, 0.080), which are the coordinates of a pure RGB light source.

Comparative Example 1_R Comparative Example 2_G Comparative Example 3_B Example 1_R Example 2_G Example 3_B filter
Transmittance - - - 78.0% 90.3% 87.8% Color coordinates
(x, y) 0.666, 0.333 0.195, 0.735 0.141, 0.046 0.671, 0.329 0.197, 0.735 0.141, 0.046

From the results of Table 1 and FIGS. 3 to 5, the organic electroluminescent device illumination of Examples 1 to 3, in which the optical filter having the adhesive layer containing a specific combination of dyes was mounted, It can be seen that the color purity of the R, G and B light is reliably improved in the light emitting state while minimizing the luminance reduction by transmitting the R, G, and B as much as possible.

100: Optical filter
101: Light diffusion film or antireflection film
102: base film
103: Adhesive layer
200: Light emitting unit
201: transparent substrate
202: positive polarity
203: organic light-emitting (EL) layer
204: negative polarity

Claims (11)

A light diffusing film or an antireflection film formed on one side of the base film, and an adhesive layer formed on the other side of the base film,
Wherein the light diffusion film or the antireflection film, the pressure-sensitive adhesive layer, or both include at least one kind of dye that absorbs a specific wavelength band. The method according to claim 1,
Wherein the dye is selected from the group consisting of a pyrrole methine type, a rhodamine type, a boron difiomethine type, a tetraazaporphyrin type, a rhodamine type, a squarane type, a cyanine type and a carbon black type dyes. filter. The method according to claim 1,
Wherein the at least one dye absorbs a wavelength band of 500 nm or more as a combination of an azo compound dye, a tetraazaporphyrin dye and a phthalocyanine dye. The method according to claim 1,
Wherein the at least one dye absorbs a wavelength band of 480 nm or less and 580 nm or more as a combination of an azo compound dye, a coumarin dye, and a rhodamine dye. The method according to claim 1,
Wherein the at least one dye absorbs a wavelength band of 600 nm or less as a combination of an azo compound dye, a rhodamine dye, and a tetraazaporphyrin dye. The method according to claim 1,
The one or more dyes are used in an amount of 0.01 to 10% by weight based on the total weight of the light-diffusing film or the antireflection film or the adhesive layer Wherein the organic electroluminescent element is an organic electroluminescent element. The method according to claim 1,
Wherein the light diffusion film or the antireflection film, the pressure-sensitive adhesive layer, or both are composed of a hydroxybenzotriazole-based dye, a tris-resorcinol-triazine chromophore dye, and a hydroxyphenyl-benzotriazole chromophora dye And at least one ultraviolet blocking agent selected from the group consisting of Wherein the organic electroluminescent element is an organic electroluminescent element. 8. The method of claim 7,
It is preferable that the ultraviolet screening agent is used in an amount of 0.01 to 10% by weight based on the total weight of the light diffusion film or the antireflection film or the adhesive layer Wherein the organic electroluminescent element is an organic electroluminescent element. An organic electroluminescent (OLED) illumination comprising the optical filter of claim 1. 10. The method of claim 9,
Wherein the color of the optical filter is the same as the color of the light source of the illumination. 10. The method of claim 9,
Wherein the illumination has a transmittance of 50 to 91% of the light emission of the organic light emitting device.

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