JP2012027298A - Color correction film and liquid crystal display device using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an inexpensive color correction film for improving color reproducibility and to provide a liquid crystal display device using the same, in a liquid crystal display device using a two-wavelength white color LED backlight as a light source composed of an LED emitting blue light and a phosphor emitting yellow light.SOLUTION: A binder resin layer or an adhesive layer containing a visible light absorbing dye having an absorption maximum in a wavelength region from 580 nm to 600 nm is laminated on one surface of a transparent substrate so as to efficiently separate a green color and a red color to improve color reproducibility.

Description

The present invention relates to a color correction film for a dual wavelength white LED composed of a blue light emitting LED and a yellow light emitting phosphor, and a liquid crystal display device using the same.

Currently, straight tube fluorescent lamps and flat fluorescent lamps are widely used as backlights for liquid crystal display devices used in color televisions and notebook personal computers. However, in recent years, LEDs (Light
The brightness of Emitting Diode) has been greatly improved, and LEDs having a wide color reproducibility area have been used as the light source of the backlight instead of the light emission of the phosphor.

  As typical methods for white LED light sources, (1) a three-wavelength white LED type that combines three LEDs of red, green, and blue light emission to form a white light source, and (2) a near-ultraviolet or violet light-emitting LED There are three types: a three-wavelength white LED type composed of red, green and blue light emitting phosphors, and (3) a two-wavelength white LED type composed of a blue light emitting LED and a yellow light emitting phosphor. The method (1) has a wider color reproducibility area than a liquid crystal display device using a fluorescent lamp, but it is not preferable in terms of power consumption and manufacturing cost because it uses three LEDs. In the case of the method (2), there is a feature that a beautiful white color can be obtained by the same light emission method as that of the three-wavelength fluorescent lamp, but there is a problem that the light emission efficiency is poor. The method (3) has the highest light emission efficiency among the above three methods and is advantageous for power consumption, but has a problem of poor color reproducibility.

The type of three-wavelength white LED with good color reproducibility has been reported in Patent Document 1, but sufficient studies have been made so far on the two-wavelength white LED that has high luminous efficiency and is advantageous for power consumption. Absent.

JP 2010-32820 A

Since the two-wavelength white LED realizes white light by combining the blue light of the blue light emitting LED and a phosphor emitting yellow, which is a complementary color, the color reproducibility is poor because green and red cannot be separated. It is an object of the present invention to provide an inexpensive color correction film that efficiently separates green and red and improves color reproducibility and a liquid crystal display device using the same.

As a result of diligent research to solve the above problems, the present inventors efficiently separate green and red by containing a pigment that absorbs a specific wavelength in the visible region in the resin of the transparent substrate, and reproduce the color. The present inventors have found an inexpensive color correction film for improving the property and a liquid crystal display device using the same, and have completed the present invention.

That is, the present invention is (1) a color correction film applied to a liquid crystal display device using a two-wavelength white LED composed of a blue light emitting LED and a yellow light emitting phosphor as a backlight, and the film is from 580 nm. A color correction film comprising a transparent resin layer containing a tetraazaporphyrin-based dye having an absorption maximum in a wavelength region between 600 nm.
(2) A liquid crystal display device using the color correction film according to (1).

The present invention can selectively absorb 580 to 600 nm in the visible light region of the emission spectrum of a dual wavelength white LED composed of a blue light emitting LED and a yellow light emitting phosphor, and efficiently separates green and red. However, color reproducibility can be improved at low cost.

It is a spectrum figure concerning Example 1 of the present invention. It is a spectrum figure concerning Example 2 of the present invention.

The color correction film of the present invention can be produced by applying a binder resin layer or adhesive layer containing a visible light absorbing dye on a transparent substrate as a minimum component, and other functions as required. The transparent resin layer which has can also be laminated | stacked.

The type and thickness of the transparent substrate used in the present invention is not particularly limited as long as it is highly transparent, has no scratches, and can withstand use as an optical film, but the thickness is 10 to 500 μm. It can be said that this is a preferable range with good properties. Specific examples include polymeric resin films such as polyester (hereinafter referred to as PET), polycarbonate, triacetate, norbornene, acrylic, cellulose, polyolefin, or urethane, and absorbs ultraviolet rays from the outside. In order to stabilize the function of the internal member, a transparent support film containing an ultraviolet absorbing material can also be used. The surface of the film may be coated with corona discharge treatment, plasma treatment, glow discharge treatment, roughening treatment, chemical treatment, anchor coating agent, primer or the like in order to improve adhesion with the coating film. .

As the transparent resin containing the visible light absorbing dye used in the present invention, a binder resin or an adhesive can be used. Dissolved and / or dispersed in a solvent with binder resin or adhesive and leveling agent, antistatic agent, antioxidant, dispersant, flame retardant, lubricant, plasticizer, UV absorber, other additives, etc. as required It can be made into a coating liquid and can be applied with a coating machine.

The binder resin is not particularly limited as long as it is easy to apply, has good adhesion between the binder resin layer and the transparent substrate, has good visible light permeability, and has no problem with surface quality. The resin may be selected from resins such as acrylic resins, polyamide resins, polyurethane resins, polyolefin resins, and polycarbonate resins. After being coated and wound into a roll, it is necessary to select a material that has a glass transition temperature and other physical properties that do not cause problems such as blocking during storage and does not adversely affect stability. In addition, when a binder resin such as thermosetting or active energy ray curable is used, a curing step is required after drying. However, the dye may be deteriorated by the curing heat or active energy ray, and the number of steps may increase. Therefore, it is desirable to use a thermoplastic binder resin unless there are special circumstances.

The pressure-sensitive adhesive is not particularly limited as long as it forms a transparent layer on the surface of the transparent substrate and does not impair the function as an optical filter, but acrylic, polyester-based, polyamide-based, polyurethane-based, polyolefin-based, Examples of the pressure-sensitive adhesive include polycarbonate-based, rubber-based, and silicon-based resins. An acrylic pressure-sensitive adhesive is preferable in terms of excellent transparency, adhesiveness, heat resistance, and the like. Acrylic pressure-sensitive adhesives are mainly composed of acrylic acid alkyl ester having no functional group, and copolymerize other monomer components other than acrylic acid alkyl ester having functional group and acrylic acid alkyl ester. It is a thing. The copolymerization ratio of other monomer components other than the acrylic acid alkyl ester having the functional group and the acrylic acid alkyl ester is 0.1 to 20 per 100 parts by weight of the acrylic acid alkyl ester component having no functional group. Part by weight, more preferably 1 to 10 parts by weight.

Examples of the acrylic acid alkyl ester having no functional group include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, pentyl (meth) acrylate, (meth Alkyl) such as hexyl acrylate, heptyl (meth) acrylate, octyl (meth) acrylate, nonyl (meth) acrylate, decyl (meth) acrylate, undecyl (meth) acrylate or dodecyl (meth) acrylate Examples thereof include alkyl acrylates or methacrylic acid alkyl esters having 1 to 12 carbon atoms, and these may be used in combination of two or more.

As a monomer other than an acrylic acid alkyl ester having a functional group or an acrylic acid alkyl ester, one that functions as a crosslinking point with a crosslinking agent to be described later is used, and the type thereof is not particularly limited. Hydroxy group-containing (meth) acrylic acid ester monomers such as 2-hydroxyethyl (meth) acrylate and hydroxypropyl (meth) acrylate, N, N-dimethylaminoethyl acrylate, N-ter-butylaminoethyl acrylate, etc. These amino group-containing (meth) acrylic acid monomers, acrylic acid, maleic acid and the like may be mentioned, and these may be used in combination of two or more.

The pressure-sensitive adhesive is preferably used in a composition that can crosslink the acrylic resin and the like by blending a crosslinking agent. As a crosslinking agent, it is suitably used according to the kind of the above-mentioned monomer. Polyisocyanate compounds such as aromatic diisocyanates, butyl etherified styrol melamine, melamine compounds such as trimethylol melamine, diamine compounds such as hexamethylene diamine or triethyl diamine, epoxy resin compounds such as bisphenol A and epichlorohydrin, urea resin A compound, a metal salt such as aluminum chloride, ferric chloride, or aluminum sulfate is used, and its blending amount is usually 100 parts by weight of acrylic resin. 5 parts by 0.005, and preferably about 3 parts by weight 0.01.

The visible light absorbing dye used in the present invention preferably has an absorption maximum at a wavelength of 580 to 600 nm and a half width of about 10 nm to 60 nm, and a tetraazaporphyrin-based dye can be suitably used. What is necessary is just to set the compounding quantity of a pigment | dye suitably, and is 0.005 to 5 weight part per 100 weight part of acrylic resins, Preferably it is about 0.01 to 3 weight part.

In order to produce the film of the present invention, known coating methods such as flow coating, spraying, bar coating, gravure coating, roll coating, blade coating, air knife coating, lip coating, and die coater are used. The processing layer is fixed by drying at 60 to 140 ° C., preferably 80 to 120 ° C., by coating so that the final film thickness is 1 to 50 μm.

By bonding the color correction film of the present invention to a liquid crystal display device using a two-wavelength white LED backlight as a light source via an adhesive layer, a liquid crystal display device with improved color reproducibility can be produced.

  Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the examples. In Examples, “part” means “part by weight” and “%” means “% by weight”. NS6W083BT (manufactured by Nichia Corporation) was used as the LED light source, and the spectrum was measured.

Example 1
A coating solution prepared by mixing and dissolving the materials shown in Table 1 uniformly in an easily adhesive PET film (trade name Cosmo Shine A4300; manufactured by Toyobo Co., Ltd.) with a comma coater, a coating speed of 1 m / min, a drying temperature. By coating at 100 ° C. so that the thickness of the adhesive layer was 18 μm, an adhesive layer was formed to obtain a color correction film. In an environmental test room (25 ° C.-65%), this film was mounted on an LED light source NS6W083BT (manufactured by Nichia Chemical), and a spectroscope USB-4000 (manufactured by Ocean Optics) was used to measure a spectral spectrum. The spectrum shown in FIG. 1 was obtained. At this time, the visible light absorbing dye had an absorption maximum of 592 nm and a half-value width of 25 nm, and effectively separated green and red, and sufficiently exhibited the performance required as a color correction film.

Table 1

Example 2
A color correction film was obtained in the same manner as in Example 1 except that the visible light absorbing dye of Example 1 was changed to the trade name TAP18 (manufactured by Yamada Chemical Co., Ltd.), a tetraazaporphyrin-based dye. When the film was attached to an LED light source and the spectrum was measured, the spectrum shown in FIG. 2 was obtained. At this time, the visible light absorbing dye had an absorption maximum of 592 nm and a half-value width of 25 nm, and effectively separated green and red, and sufficiently exhibited the performance required as a color correction film.

Claims (2)

  A color correction film applied to a liquid crystal display device using a two-wavelength white LED composed of a blue light emitting LED and a yellow light emitting phosphor as a backlight, and the film absorbs in a wavelength region between 580 nm and 600 nm. A color correction film comprising a transparent resin layer containing a tetraazaporphyrin-based dye having a maximum value. A liquid crystal display device using the color correction film according to claim 1.

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