JP2009198749A - Light beam control member - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a light beam control member capable of making a light beam control function compatible with an average light transmittance of the light beam control member from a display side, and allowing stable manufacturing. <P>SOLUTION: This light beam control member has a plurality of light absorption parts and light transmission parts provided with a prescribed interval to be perpendicular to obverse and reverse faces and to be parallel to each other, and an observing side surface of each light transmission part is located lower than a plane connecting to observing side surfaces of the respective light absorption parts. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention is installed on the front of the display and has a function of preventing the deterioration of image quality due to a decrease in contrast when the display is exposed to external light, and a viewing angle by suitably diffusing the effective light of the display. The present invention relates to a light beam control member having a widening function and the like.

  In recent years, thin and large-screen displays have rapidly expanded the market. Thin, large-screen displays include liquid crystal displays, plasma displays, rear projection televisions, and the like. Further, as next-generation displays, research on organic EL displays or FEDs (Field Emission Displays) is also progressing.

  The technology of both displays is remarkable, and the drawbacks of each method have been resolved every year, but the disadvantage of low contrast in bright rooms (light contrast) has been improved in plasma displays, organic EL, etc. There is a lot of room.

  Contrast is represented by the ratio of the brightness of white display to black display. The contrast in the absence of external light (dark place contrast) is high for self-luminous plasma displays, organic EL displays, and the like. This is because complete black display is possible by stopping the light emission, while the bright place contrast is higher in the liquid crystal display. This is because an optical member that absorbs light, such as a color filter and a polarizing plate, is provided inside the display, and external light incident on the display is hardly emitted from the display surface again. In a plasma display or organic EL, there is generally no color filter or polarizing plate inside the display, and incident external light enters the display, is reflected by internal electrodes, etc., and is emitted from the display surface again. Since it cannot be displayed, the contrast in the light place is lowered.

In recent years, a display filter including a light beam control member in which a plurality of light absorbing portions are arranged in a stripe shape has been proposed in order to suppress a decrease in contrast due to external light. (Patent Documents 1, 2, 3, 4)
In Patent Document 1, as for the shape of the display filter, two light diffusing sheets provided with a plurality of unit lenses having a substantially trapezoidal cross-sectional shape are overlapped with a phase shifted, and the unit lenses are formed of a high refractive material and are adjacent to each other. The unit lenses are formed of a low refractive material having a lower refractive index than the high refractive material, and the refractive index of the high refractive material is N1, the refractive index of the low refractive material is N2, and the top of the trapezoid. Assuming that the bottom length is T, the height is H, and the angle between the trapezoid hypotenuse and the normal line of the light emitting portion is θ, sin (90 ° −θ)> N2 / N1 N1 <1 / sin2θ and 0 There has been proposed a two-dimensional viewing angle widening member configured such that the relationship <H <T / (tan (2θ + 10 °) −tan θ) is established.

  In Patent Documents 2 and 3, in order to increase the visibility of the display, a first layer composed of a light absorption layer and a light transmission portion in the thickness direction from the display surface toward the observation side, and at least one other layer. A visibility improving sheet composed of the above second layer has been proposed. Further, in Patent Document 2, the refractive index of the light transmission portion of the first layer is set to be higher than the refractive index of the second layer provided on the display surface side of the first layer sharing the interface with the first layer. It is also proposed that the refractive index be high.

  Patent Document 4 proposes a viewing angle control sheet in which trapezoidal lens sections are arranged at predetermined intervals, and light-absorbing particles are added to wedge-shaped sections between adjacent lens sections to develop a light absorption effect. Has been.

In addition, as another method for suppressing a decrease in contrast due to external light, the following proposals have been made (Patent Documents 5 and 6).
Patent Document 5 proposes a plasma display panel in which a front filter is provided between a front substrate and a rear substrate, and the average transmittance of visible light of these front substrate and front filter is 60 to 80%, respectively.

In Patent Document 6, a light absorber having an absorption peak in the vicinity of 500 nm and an absorption peak in the vicinity of 560 nm to 600 nm in the material constituting the front panel for a transmissive screen on which the image from the image source is projected from the back surface. And a light absorber having absorption peaks near 600 nm and at 660 nm or more have been proposed.
JP 2003-0666206 A JP 2004-062084 A JP 2004-062099 A JP 2006-088876 A JP 2000-164145 A JP 2001-238226 A

In the light beam control member used to suppress such a decrease in contrast due to external light, the following problems are required to be solved.
(I) The light transmittance from the display side of the light beam control member is low.
(Ii) It has wavelength dependency and incident angle dependency of external light to be blocked.
(Iii) It is difficult to manufacture stably.

  With respect to these problems, particularly (i), in Patent Document 1, as described above, the shape and the refractive index are defined as sin (90 ° −θ)> N2 / N1 N1 <1 / sin2θ. A part of the light emitted from the light is reflected on the surface of the light absorbing portion, and further, 0 <H <T / (tan (2θ + 10 °) −tan θ), so that the reflected light is not absorbed again by the light absorbing portion. Proposes how to do so. However, this method cannot secure a sufficient light transmittance from the display side, and is not conceived by the solution of the present invention.

  Patent Document 2 proposes to increase the average light transmittance from the display side by providing two or more layers in the light transmission direction and changing the refractive index of the light transmission part of the two layers. In this method, it is difficult to significantly improve the light transmittance from the display side while maintaining the suppression of the decrease in contrast due to external light, and the solution of the present invention is not conceived.

  Patent Document 3 proposes to provide a second layer for diffusing light provided on the observation side, but its improvement effect is insufficient, and the solution of the present invention relating to the shape of the surface of the light transmission part There is no idea.

  In Patent Document 4, a light shielding portion is formed between trapezoidal lenses and the light on the display side is efficiently extracted to improve the transmittance. However, the effect is insufficient, and the solution of the present invention There is no idea.

  In Patent Document 5, the average light transmittance from the display side is high, but the contrast ratio of the display is as low as 50: 1, and the contrast improvement effect is insufficient.

  In Patent Document 6, since the wavelength of the light absorber is restricted, the light beam control function is manifested only by the influence of external light from a specific type of light source, and the effect is insufficient.

  Therefore, an object of the present invention is to provide a light beam control member that can provide both a light beam control function and maintain a light transmittance from the display side and can be manufactured more stably.

The said subject can be achieved by the present invention in any one of the following (1) to (7).
(1) A light beam control member in which a light absorbing portion and a light transmitting portion are alternately provided in one direction on one surface layer portion, and the surface of the light transmitting portion is more than a surface connecting the surfaces of the light absorbing portions. A light beam control member characterized by being recessed.
(2) The light beam control member according to (1), wherein a surface shape of the light transmission portion is a concave lens shape.
(3) the refractive index n ₂ of the refractive index n ₃ of the light absorbing portion light transmitting portion is characterized in that the range of the following, the light beam control member according to (1) or (2).

(4) The cross-sectional shape of the light absorbing portion is a rectangle, trapezoid, or triangle, the height of the rectangle, trapezoid, or triangle is d, the width of the light transmitting portion is H, and the radius of curvature of the surface of the light transmitting portion is r. The light control member according to any one of (1) to (3), wherein when the refractive index of the light transmission part is n ₂ , the height d is in the following range.

(5) The cross-sectional shape of the light absorbing portion is a rectangle, trapezoid, or triangle, and the height d of the rectangle, trapezoid, or triangle, the pitch p of the light transmitting portion, and the width w of the light absorbing portion satisfy the following expression. The light beam control member according to any one of (1) to (4), wherein:

(6) A light beam control member in which a light absorbing portion and a light transmitting portion are alternately provided in one direction on one surface layer portion, and the refractive index of the light transmitting portion is a center point of the surface of the light transmitting portion A light beam control member characterized by being concentrically lowered.
(7) A light diffusing layer, an antireflection layer, an antiglare layer, an antistatic layer, a hard coat layer, and a protective layer are formed on the surface of the light control member according to any one of (1) to (6). A light beam control member, wherein at least one soil layer is formed.

  ADVANTAGE OF THE INVENTION According to this invention, while providing the light control function and maintaining the high light transmittance from a display, the light control member which can be manufactured stably is obtained.

Before describing a specific embodiment, the mechanism of the present invention will be described.
First, regarding the known technique, the reason why the average light transmittance from the display side of the light beam control member is low will be described.

  In the above-described Patent Documents 1 to 4, the principle of expressing a light beam control function that shields external light incident from the observation surface side is the observation surface side by providing a light absorbing portion parallel to the light transmission direction of the light beam control member. In this case, a light beam incident at a certain angle enters the light absorption unit before passing through the light transmission unit, or is absorbed by entering the light absorption unit when entering the light control member surface. is there. Therefore, in order to increase the absorption efficiency of external light incident from the observation surface, it is necessary to (i) reduce the width of the light transmission portion and (ii) increase the height of the light absorption portion. On the other hand, in order to increase the average light transmittance from the display side, it is necessary to (i) widen the width of the light transmitting portion, and (ii) reduce the height of the light absorbing portion. The function becomes a trade-off relationship.

  In response to this principle problem, Patent Documents 1 to 4 propose a method for increasing the average light transmittance from the display surface side by various methods as described above, but increase the external light absorption efficiency itself. There is no idea about the method, and it simply relies on the height of the light absorption part, and as a result, the light transmittance from the display side is not significantly improved.

On the other hand, the present invention has improved both the external light absorption efficiency and the average light transmittance from the display side by using the following three methods which have not been conventionally used.
(I) Introducing the concept of guiding light incident from the observation side to the light absorption part by changing the surface shape on the observation side of the light transmission part or the refractive index distribution of the light transmission part, and the height of the light absorption part It is possible to efficiently absorb outside light even if the temperature is low.
(Ii) By defining the difference in refractive index between the light absorbing portion and the light transmitting portion, reflection at the interface between the light transmitting portion and the light absorbing portion within the light beam control member was suppressed, and the light absorption efficiency of external light was increased.
(Iii) By reducing the height of the light absorbing portion, it is possible to increase the average light transmittance from the display side, and achieve the departure from the aforementioned trade-off relationship.

  Next, the reason why it is difficult to manufacture stably at low cost will be described with respect to the known technology.

  As described above, in Patent Documents 1 to 4, in principle, it is necessary to increase the height of the light transmission part. Therefore, the aspect ratio, that is, (the height of the light absorption part) is determined when the light transmission part or the light absorption part is molded. It is necessary to make a molded body having a structure of (d / light transmission portion pitch p-light absorption portion width w) or (light absorption portion height d / light absorption portion width w). Making a molded body with a high aspect ratio has many problems such as mold release properties at the time of molding, making stable production difficult.

  On the other hand, in the present invention, by using the above-described method, a light control function is imparted while maintaining a high light transmittance from the display while keeping the height d of the light absorbing portion low, and the manufacture is facilitated. Made it possible to do. Hereinafter, embodiments of the present invention will be specifically described.

(1) Shape of the light beam control member according to the present invention The light beam control member according to the present invention has, for example, as shown in FIGS. The surface of the light transmitting portion 4 is recessed from the surface connecting the surfaces of the light absorbing portion 2. FIG. 1 is a schematic view of a light beam control member 1 in which light absorbing portions 2 and light transmitting portions 4 are alternately provided in one direction on a surface layer portion, as observed from the observation side surface. FIG. 2 is a perspective view of the light beam control member 1 shown in FIG. 1 and shows a state in which the observation side surface of the light transmission part 4 is recessed from the surface connecting the observation side surface of the light absorption part 2. FIG. 3 is a cross-sectional view taken along the line AA of the light beam control member 1 shown in FIG. 1, and shows a state where one surface of the light transmission part 4 is formed in the shape of the concave lens 5. By making the shape of the observation side surface of the light beam control member as described above, it becomes possible to refract external light incident from the front side of the observation surface and guide it to the adjacent light absorbing portion. Therefore, even if the height of the light absorption part 2 is suppressed, more external light can be absorbed, so that it is possible to achieve both the light control function and the high light transmittance from the display. Moreover, since the height of the light absorption part 2 can be suppressed, it becomes easy to manufacture stably.

  As shown in FIGS. 2 and 3, the observation side surface of the light transmitting portion 4 is recessed as shown in FIGS. 2 and 3 in order to refract external light more efficiently and not affect the light emitted from the display side. More preferably, it is a concave lens shape. Here, the concave lens shape is a general term for lenses having a negative focal length, and includes a single concave lens, a biconcave lens, and the like, but a single concave lens that is easy to manufacture is preferable.

  Further, the cross-sectional shape of the concave lens 5 may be any of a semicircle, a semi-ellipse, a normal line, and the like as long as light incident from this surface can be refracted and guided to the light absorbing portion.

  On the other hand, the shape of the light absorbing portion 2 is not particularly limited, and for example, as shown in FIG. 3, the cross section may be rectangular, trapezoid (FIG. 4), or triangle (FIG. 5). The light beam control member shown in FIGS. 4 and 5 has the same configuration as that of the light beam control member shown in FIGS.

In light control member according to the present invention, to enhance the absorption efficiency of the external light to prevent reflection at the interface of the light transmitting portions and light absorbing portions, the refractive index n ₃ of the light absorbing portion 2 and the refractive index of the light transmitting portion 4 n ₂ is preferably within a predetermined range represented by the following formula.

In the light beam control member according to the present invention, from the viewpoint of effectively suppressing a decrease in contrast due to external light, the height d of the light absorption unit, the width H of the light transmission unit, and the light beam of the light transmission unit shown in FIG. When the curvature radius r of the surface and the refractive index n ₂ of the light transmitting portion are satisfied, the following preferable relationship exists in the height d. FIG. 6 shows a case where the cross-sectional shape of the light absorbing portion 2 is rectangular. However, when the cross-sectional shape of the light absorbing portion 2 is trapezoidal or triangular, the bottom of the trapezoid or the bottom of the triangle is shown. The width H of the light transmission part is taken on the extension line.

  Satisfying this relational expression means that β represents the position from the light absorbing portion when the light absorbing portion is represented by 0 and the light transmitting portion central portion is represented by 1, so that the light beam incident between 0 and β is It means a light absorbing part having a height to be absorbed.

  In the above relational expression, β is preferably 0.25, and more preferably 0.4. That is, it is preferable that the light beam incident between the light absorption part and the position where β = 0.25, and further β = 0.4 is absorbed by the light absorption part.

  In the light beam control member according to the present invention, from the viewpoint of increasing the light transmittance from the display side, the height d of the light absorbing portion, the pitch p of the light transmitting portion, and the width w of the light absorbing portion shown in FIG. It is preferable to satisfy the predetermined range shown in the formula.

FIG. 6 shows the height and width when the cross-sectional shape of the light absorbing portion 2 is rectangular. However, when the cross-sectional shape is a trapezoid, the length of the bottom of the trapezoid corresponds to w. When the cross-sectional shape is a triangle, the length of the base corresponds to w.

  Moreover, as another aspect of the light beam control member according to the present invention, as shown in FIG. 7, a member in which a light transmission part 4 and a light absorption part 2 are formed on a base material 6 can be exemplified.

  Further, the same effect can be obtained by changing the refractive index distribution in the light transmitting portion instead of changing the surface shape of the light transmitting portion, preferably by lowering the refractive index concentrically from the center point of the surface on which the external light is incident. can get. This is because light is refracted in the light transmitting part and guided to the light absorbing part. FIG. 8 is a schematic diagram showing that the refractive index is concentric from the high refractive index part at the center of the observation side surface of the light transmitting part. It shows that it is low.

  As an aspect of the present invention, a light diffusing layer, an antireflection layer, an antiglare layer, an antistatic layer, a hard coat layer, and an antifouling layer are provided on at least a part of the observation side surface of the light control member, preferably a light transmitting portion. An example in which at least one of the above is formed can also be exemplified. FIG. 9 shows a schematic cross-sectional view (corresponding to the AA cross-sectional view of FIG. 1) in an example of this light control member. In FIG. 9, an antireflection layer 7 is formed on the concave lens 5 of the light transmission part 5.

(2) Light transmission part forming material In the present invention, the light transmission part has a curability such as a resin, oligomer, monomer and mixture thereof, or a thermosetting composition that is cured by ionizing radiation such as ultraviolet rays or electron beams. Resin can be used. In particular, the ionizing radiation curable composition is preferable because it has a high curing rate and excellent productivity, and is excellent in durability to a coating composition and a solvent used for coating the light control member.

  The ionizing radiation curable composition may include, for example, an ionizing radiation curable resin, oligomer, monomer, and a mixture thereof. The above resin, oligomer, and monomer may include ethylenically unsaturated diene in the molecule. Those having a double bond are preferred.

  As the compound having an ethylenically unsaturated double bond in the molecule, preferably used as an ionizing radiation curable composition, specifically, a compound having 1 to 3 ethylenically unsaturated double bonds, 4 The compound etc. which have the above ethylenically unsaturated double bond can be mentioned. In consideration of accuracy and scratch resistance when the light transmission part and the light absorption part are formed in a stripe shape, it is preferable to use a polyfunctional acrylate as the main component.

  As such a polyfunctional acrylate, a monomer, oligomer, or prepolymer having 3 (more preferably 4, more preferably 5) or more (meth) acryloyloxy groups in one molecule is preferably used (however, In the present specification, “... (Meth) acryl ...” is an abbreviation of “... Examples of such compounds include compounds in which the hydroxyl group of a polyhydric alcohol having 3 or more alcoholic hydroxyl groups in one molecule is an esterified product of 3 or more (meth) acrylic acids. it can.

  Specific examples include pentaerythritol tri (meth) acrylate, pentaerythritol tetra (meth) acrylate, dipentaerythritol tri (meth) acrylate, dipentaerythritol tetra (meth) acrylate, dipentaerythritol penta (meth) acrylate, di Use pentaerythritol hexa (meth) acrylate, trimethylolpropane tri (meth) acrylate, pentaerythritol triacrylate hexamethylene diisocyanate urethane prepolymer, pentaerythritol triacrylate toluene diisocyanate urethane prepolymer, pentaerythritol triacrylate isophorone diisocyanate urethane prepolymer, etc. be able to. These may be used alone or in combination of two or more.

  The use ratio of the monomer, oligomer or prepolymer having 3 or more (meth) acryloyloxy groups in one molecule is preferably 50 to 90% by mass, more preferably 50% to the light transmitting part forming material. -80 mass%.

  In addition to the above compounds, the light transmitting part forming material may be one or two ethylenic groups in one molecule for the purpose of relaxing rigidity, reducing shrinkage during curing, or adjusting the viscosity of the coating liquid. It is preferable to use a monomer having an unsaturated double bond in combination.

  The monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule can be used without particular limitation as long as it is a normal monomer having radical polymerizability.

  As the monomer having two ethylenically unsaturated double bonds in one molecule, the following (a) to (f) (meth) acrylates and the like can be used.

(A) (meth) acrylic acid diesters of alkylene glycol having 2 to 12 carbon atoms: ethylene glycol di (meth) acrylate, propylene glycol di (meth) acrylate, 1,4-butanediol di (meth) acrylate, Neopentyl glycol di (meth) acrylate, 1,6-hexanediol di (meth) acrylate, etc.
(B) (Meth) acrylate diesters of polyoxyalkylene glycol: diethylene glycol di (meth) acrylate, triethylene glycol di (meth) acrylate, tetraethylene glycol di (meth) acrylate, dipropylene glycol di (meth) acrylate, Polyethylene glycol di (meth) acrylate, polypropylene glycol di (meth) acrylate, etc.
(C) Polyhydric alcohol (meth) acrylic acid diesters: pentaerythritol di (meth) acrylate, etc.
(D) (Meth) acrylic acid diesters of ethylene oxide and propylene oxide adducts of bisphenol A or bisphenol A hydride: 2,2′-bis (4-acryloxyethoxyphenyl) propane, 2,2′-bis ( 4-acryloxypropoxyphenyl) propane, etc.
(E) Two or more in a molecule obtained by reacting a terminal isocyanate group-containing compound obtained by reacting a diisocyanate compound and two or more alcoholic hydroxyl group-containing compounds in advance with an alcoholic hydroxyl group-containing (meth) acrylate. Urethane (meth) acrylates having a (meth) acryloyloxy group, and the like, and
(F) Epoxy (meth) acrylates having two or more (meth) acryloyloxy groups in the molecule obtained by reacting a compound having two or more epoxy groups in the molecule with acrylic acid or methacrylic acid.

  Monomers having one ethylenically unsaturated double bond in the molecule include methyl (meth) acrylate, ethyl (meth) acrylate, n- and i-propyl (meth) acrylate, n-, sec-, And t-butyl (meth) acrylate, 2-ethylhexyl (meth) acrylate, lauryl (meth) acrylate, stearyl (meth) acrylate, methoxyethyl (meth) acrylate, ethoxyethyl (meth) acrylate, hydroxyethyl (meth) acrylate, Polyethylene glycol mono (meth) acrylate, polypropylene glycol mono (meth) acrylate, glycidyl (meth) acrylate, tetrahydrofurfuryl (meth) acrylate, N-hydroxyethyl (meth) acrylamide, N-vinylpyrrolidone, - vinyl-3-methylpyrrolidone, or the like can be used N- vinyl-5-methyl pyrrolidone. These monomers may be used alone or in combination of two or more.

  The use ratio of the monomer having 1 to 2 ethylenically unsaturated double bonds in one molecule is preferably 10 to 40% by mass, more preferably 20 to 40% with respect to the light transmitting part forming material. % By mass.

  When using, for example, ultraviolet rays as the ionizing radiation used for curing the ionizing radiation curable composition, it is preferable to contain a known photopolymerization initiator in the ionizing radiation curable composition.

  Further, the light transmissive portion forming material can contain a modifier. As modifiers, coatability improvers, antifoaming agents, thickeners, antistatic agents, inorganic particles, organic particles, organic lubricants, organic polymer compounds, UV absorbers, light stabilizers, dyes, Pigments, refractive index modifiers, stabilizers, and the like can be used, and these are used as light transmitting composition components within a range that does not impair the reaction with actinic radiation or heat, and can improve the characteristics depending on the application. it can.

  As the light transmission part forming material, a commercially available polyfunctional acrylic curable paint can be used. Such cured paints include Mitsubishi Rayon Co., Ltd. (trade name “Diabeam” series, etc.), Nagase Sangyo Co., Ltd. (trade name “Denacol” series, etc.), Shin-Nakamura Co., Ltd. (trade name “NK Ester” series, etc.) Dainippon Ink and Chemicals Co., Ltd .; (trade name “UNIDIC” series, etc.), Toa Synthetic Chemical Industry Co., Ltd. (trade name “Aronix” series, etc.), Nippon Oil & Fats Co., Ltd. (trade name “Blemmer” series) Nippon Kayaku Co., Ltd .; (trade name “KAYARAD” series, etc.), Kyoeisha Chemical Co., Ltd. (trade names “light ester” series, “light acrylate” series, etc.), JSR Corporation; (trade name “Desolite”) Products such as “series” can be used.

(3) Light Absorbing Part Forming Material The light absorbing part of the present invention is mainly composed of a mixture of the light transmitting part forming material and a black pigment dispersion, and if necessary, the bis-functional or lower acrylate and polymerization. Initiators and modifiers can be used.

Examples of the black pigment dispersion include carbon black, polymer dispersion of black metal particles such as titanium and iron, and the like. When the extinction coefficient of the black pigment dispersion is about 1 × 10 ⁶ m ⁻¹ , the content of the black pigment dispersion is 5 to 80 parts, preferably 10 to 50, with respect to 100 parts by weight of the light transmitting part forming material. It is desirable to be in the range of parts by weight.

(4) Base Material In the present invention, as described above, the light transmission part 4 and the light absorption part 2 may be provided on the base material. In this case, a plastic film is used as the base material. The plastic film is not particularly limited, and a plastic film composed of polyester, polyolefin, cyclic polyolefin, polyamide, triacetyl cellulose, acrylic, polyurethane, or the like can be preferably used, and a polyester film is particularly preferable.

  Although it does not specifically limit as polyester of a polyester film, A polyethylene terephthalate, a polyethylene naphthalate, a polypropylene terephthalate, a polybutylene terephthalate, a polypropylene naphthalate, etc. are mentioned, These 2 types or more may be mixed. Further, it may be a polyester in which these and other dicarboxylic acid components or diol components are copolymerized. In this case, in the film in which the crystal orientation is completed, the crystallinity is preferably 25% or more, more preferably Is preferably a plastic film of 30% or more, more preferably 35% or more. When the crystallinity is less than 25%, dimensional stability and mechanical strength tend to be insufficient. The crystallinity can be obtained by a density gradient method (JIS-K7112 (1980)) or a Raman spectrum analysis method.

  When the above-described polyester is used as the plastic film, its intrinsic viscosity (measured in o-chlorophenol at 25 ° C. according to JIS K7367-5 (2000)) is 0.4 to 1.2 dl / g. Is more preferable, and 0.5 to 0.8 dl / g is more preferable.

  Further, the plastic film used as the substrate may be a composite film having a laminated structure of two or more layers. As the composite film, for example, a composite film that is substantially free of particles in the inner layer portion and provided with a layer containing particles in the surface layer portion can be exemplified, and the inner layer portion and the surface layer portion are chemically separated. Different polymers or the same kind of polymers may be used.

When used for a display which is the intended use of the present invention, it is preferable that the plastic film does not contain particles from the viewpoint of optical properties such as transparency without internal scattering.
The thickness of the plastic film is not particularly limited, but is preferably 10 to 500 μm, more preferably 20 to 300 μm, and particularly preferably 50 to 200 μm from the viewpoint of mechanical strength and handling properties.

  The plastic film may contain various additives, resin compositions, cross-linking agents and the like within a range that does not impair the effects of the present invention. For example, antioxidants, heat stabilizers, ultraviolet absorbers, organic and inorganic particles (for example, silica, colloidal silica, alumina, alumina sol, kaolin, talc, mica, calcium carbonate, barium sulfate, carbon black, zeolite, titanium oxide, Metal fine powders), pigments, dyes, antistatic agents, nucleating agents, acrylic resins, polyester resins, urethane resins, polyolefin resins, polycarbonate resins, alkyd resins, epoxy resins, urea resins, phenol resins, silicone resins, rubber resins , Wax composition, melamine crosslinking agent, oxazoline crosslinking agent, methylolated, alkylolized urea crosslinking agent, acrylamide, polyamide, epoxy resin, isocyanate compound, aziridine compound, various silane coupling agents, various titanates And the like can be mentioned system coupling agent.

(5) Manufacturing method Next, the manufacturing method of the light beam control member of this invention is demonstrated. The light beam control member of the present invention is manufactured through, for example, the following steps.
(I) Step 1 of supplying a light transmission part forming material onto a substrate
(Ii) Step 2 in which the base material supplied with the light transmitting portion forming material is pressed against the mold
(Iii) Step 3 of curing the light transmitting portion forming material filled between the base material and the mold by pressure contact to form a light transmitting portion molded body having a groove on the base material.
(Iv) Step 4 of peeling the light transmission part molded body formed on the substrate by curing from the mold
(V) Step 5 of filling the groove of the molded body with the light absorbing portion forming material
(Vi) Step 6 of curing the light absorbing portion forming material
(Vii) Step 7 of peeling the molded body from the base material
Steps 1 to 4 will be further described with reference to FIG. In step 1, the light transmitting portion forming material is supplied to the base material 6 using the supply device 9. As the light transmission part forming material supply device 9, for example, various blade coaters, roll coaters, bar coaters, rod blade coaters, curtain coaters, gravure coaters, and extrusion methods are used so as to obtain an accurate coating amount. Various coating apparatuses such as a coater were appropriately selected and used. In particular, a coater using an extrusion method is preferable.

  Next, in step 2, the base material 10 to which the light transmitting portion molding material is supplied is pressed against the mold 12 using the press roll 11. The mold has a protrusion corresponding to the shape of the groove for filling the light absorbing portion forming material in a later step, and such a convex portion (such as a dent on the light transmitting portion observation side surface in the finally obtained light control member ( Preferably, a roll in which a plurality of convex portions corresponding to the concave lens are formed in parallel to the circumferential direction of the roll can be used. FIG. 11 is a perspective view of the roll, and FIG. 12 is a cross-sectional view of the roll of FIG. In the roll 16 shown in these drawings, a plurality of projections 17 corresponding to the shape of the groove formed in the light transmission portion molding and a plurality of convex portions 18 corresponding to the concave lens are provided in parallel to the circumferential direction. Hereinafter, such a roll is referred to as a mold.

  The thickness of the light transmission part obtained in this step is adjusted by the supply amount of the light transmission part forming material supply device 9, the pressure of the pressure roller 11 and the tension of the base material on the mold.

  In step 3, the light transmitting portion forming material is cured on the mold 12 with the irradiation device 13 (for example, ionizing radiation such as ultraviolet rays and electron beams) described in the above-described light absorbing portion and light transmitting portion curing method. In Step 4, the release roll 14 is used to release the mold 12 to obtain a light transmission part molded body 15.

  Next, the process from the process 5 to the process 7 is demonstrated based on FIG. In step 5, the light absorbing part forming material is supplied to the light transmitting part molded body 19 by the supply device 20. The supply device 20 uses the same device as the light transmission portion forming material supply device 9. Next, the groove part of the light transmission part molding is filled with the light absorbing part forming material using the press roll 21. Thereafter, in Step 6, the surplus portion is scraped off using the blade 22, and the light absorbing portion forming material is cured by the irradiation device 23 described in the curing method of the light transmitting portion. In Step 7, the peeling roll 24 is used. Then, the light beam control member 25 is peeled off from the substrate.

Next, although this invention is demonstrated based on an Example, this invention is not necessarily limited to these. In addition, the measuring method of the characteristic in this invention and the evaluation method of an effect are as follows.

(1) Material property measurement <Evaluation of refractive index>
In accordance with JIS K7142-1996, the refractive index of the light absorbing part forming material and the light transmitting part forming material is coated, cured and peeled in advance on a releasable plastic film to form a film. Was measured using an Abbe refractometer (NAR-1T SOLID, manufactured by Atago Co., Ltd.), a test piece for film measurement, and an intermediate solution.

  The refractive index of the product after molding can be measured by Opti-Probe 2000 manufactured by Therma Wave.

(2) Functional evaluation of light beam control member
<Evaluation of photopic contrast>
The light control member was attached to the plasma display, and the bright contrast was evaluated. In order to confirm the bright place contrast improvement effect by this invention, sensory evaluation by 10 persons was implemented.

  The plasma display was installed so that the display screen of the plasma display was at an angle of about 40 degrees with respect to the room lamp installed near the ceiling. The illuminance on the display surface by the interior lighting was about 168 lx for the horizontal plane and about 200 lx for the vertical plane.

The observer observed an image with a small contrast difference at a position 1.5 m away from the display. Evaluating points for 8 people, using the front filter (blank) that does not have an external light shielding layer as a reference, using a four-level scoring system, and removing the maximum value and the minimum value one by one from the evaluation results for 10 people And the evaluation results were digitized. The results are shown in Table 1.
・ 0 point Equivalent to the front filter without external light shielding layer ・ 1 point Somewhat good ・ 2 points Quite good ・ 3 points Very good.

<Evaluation of screen brightness>
Sensory evaluation of screen brightness was performed under the same conditions as for bright place contrast evaluation.

Based on the front filter (blank) that does not have an external light shielding layer, the following four-step scoring method is used, and the maximum value and the minimum value are removed from the evaluation result of 10 persons, one for each of 8 persons. The evaluation points were averaged to quantify the evaluation results.
・ 0 point feels very dark ・ 1 point feels very dark ・ 2 points feels a little dark ・ 3 points Equivalent to a front filter without an external light shielding layer

(3) Manufacturing stability evaluation <Evaluation of molding stability>
The light transmissive part was molded, and the following determination was made from the number of possible moldings until a defective part unacceptable for the molded product was visually observed.
○: 15 times or more △: 5 times or more 15 times or less
X: 5 times or less (Example 1)
1. Light transmitting part forming material, light absorbing part forming material (preparation of light transmitting part molding material)
The following materials were mixed and defoamed to obtain a light transmission part forming material.
UV curable resin “Desolite Z7528 manufactured by JSR Corporation”: 70 parts by weight 1,6-hexanediol diacrylate: 30 parts by weight Photoinitiator (ESACURE KIP150 manufactured by Sartomer Japan): 3 parts by weight (light absorption part) Preparation of forming material)
The following materials were mixed and defoamed to obtain a light transmission part forming material.
UV curable resin “Desolite Z7528 manufactured by JSR Co., Ltd.”: 60 parts by weight 1,6-hexanediol diacrylate: 20 parts by weight Black pigment dispersion (FD Carton ACE Sumitomo Toyo Ink Co., Ltd.): 20 parts by weight interface Activator (Megafac F-482 manufactured by Dainippon Ink Co., Ltd.): 0.1 part by weight Photoinitiator (ESACURE KIP150 manufactured by Sartomer Japan Co., Ltd.): 3 parts by weight Light transmitting part molding material n ₂ , refractive index of the light transmitting portion molding material _{n 3} was 1.52 both.

2. Molding A mold having a configuration corresponding to the shape of the light absorbing portion and the light transmitting portion of FIG.
(Structure A)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r of the light transmitting part surface: 30 μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.35.

3. Manufacturing Method of Light Control Member Using the above-described light transmission part molding material, a PET film (T-60 manufactured by Toray Industries, Inc.) having a thickness of 50 μm is used as a base material, and the integrated irradiation intensity is as shown in FIG. By irradiating with an ultraviolet ray of 600 mJ / cm ² , a long sheet-shaped light transmission part molded body having a plurality of grooves formed in parallel in a stripe shape was obtained. The thickness of the light transmission part molded body 15 was adjusted to 30 μm by adjusting the supply amount of the supply device 9, the pressing pressure of the pressing roll 11, and the tension of the base material on the mold.

Furthermore, by using the above-described light absorbing portion forming material, the light absorbing portion forming material is filled in the groove portion of the light transmitting portion molding, the surplus portion is scraped off, and the integrated irradiation intensity is 600 mJ / mm in the manufacturing method shown in FIG. After curing by irradiating with ultraviolet rays of ² cm ² , the sheet-like light control member 25 was obtained by peeling from the substrate. The total thickness of the light control member thus obtained was 50 μm.

(Example 2)
To obtain a light control member except that the refractive index n ₃ of the light-absorbing portion forming material and 1.51 in the same manner as in Example 1.

(Example 3)
A light beam controlling member was obtained in the same manner as in Example 1 except that a mold corresponding to the configuration of the structure B was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure B)
Cross section of light absorbing part: trapezoid
Trapezoidal tilt angle: 2 °
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r of the light transmitting part surface: 30 μm
Width w of light absorbing portion: 10 μm (the length of the lower base of the trapezoid)
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.35.

Example 4
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the configuration of the structure C was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure C)
Cross section of light absorbing part: triangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r of the light transmitting part surface: 30 μm
Light absorption part width w: 10 μm (the length of the base of the triangle)
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.35 μm.

(Example 5)
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the configuration of the structure D was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure D)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r of the light transmitting part surface: 40 μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 40 μm
Width H of light transmission part: 40 μm
β: 0.25.

(Example 6)
A light beam controlling member was obtained in the same manner as in Example 1 except that a mold corresponding to the structure E was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure E)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r on the surface of the light transmission part: 23 μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.4.

(Example 7)
A light beam controlling member was obtained in the same manner as in Example 1 except that a mold corresponding to the configuration of the structure F was used in the shapes of the light absorbing portion and the light transmitting portion in FIG.
(Structure F)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature of light transmission surface r: 30μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 40 μm
Width H of light transmission part: 40 μm
β: 0.3.

(Example 8)
A light beam controlling member was obtained in the same manner as in Example 1 except that a mold corresponding to the configuration of the structure G was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure G)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r of the light transmitting part surface: 30 μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 60 μm
Width H of light transmission part: 40 μm
β: 0.40.

Example 9
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure H was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure H)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature r of the light transmitting part surface: 30 μm
Light absorber width w: 17 μm
Light absorption portion pitch p: 57 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.35.

(Example 10)
To obtain a light control member except that the refractive index n ₃ of the light-absorbing portion forming material and 1.50 in the same manner as in Example 1.

Example 11
A light beam controlling member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure L was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure L)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature of light transmission surface r: 58μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.22.

Example 12
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure M was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure M)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature of light transmission surface r: 30μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Height of light absorbing part d: 73 μm
Width H of light transmission part: 40 μm
β: 0.45.

(Example 13)
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure N was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure N)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature of light transmitting surface r: 36 μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorption part height d: 30 μm
Width H of light transmission part: 40 μm
β: 0.22.

(Example 14)
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure O was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure O)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: hemispherical surface (observation surface side is concave lens shape)
Radius of curvature of light transmission surface r: 30μm
Light absorption part width w: 20 μm
Light absorption part pitch p: 60 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm
β: 0.35.

(Comparative Example 1)
A light beam control member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure I was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure I)
Cross section of light absorbing part: rectangle
Surface shape of light transmission part: Width w of flat light absorption part: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width of light transmission part H: 40 μm.

(Comparative Example 2)
Example 1 except that a mold corresponding to the shape of the structure J is used in the shape of the light absorption part and the light transmission part in FIG. 15 and the refractive index n ₃ of the light absorption part forming material is 1.48. Similarly, a light beam control member was obtained.
(Structure J)
Cross section of light absorbing part: trapezoid
Trapezoidal tilt angle: 2 °
Surface shape of light transmission part: Width w of flat light absorption part: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 80 μm
Width H of light transmission part: 40 μm.

(Comparative Example 3)
A light beam controlling member was obtained in the same manner as in Example 1 except that a mold corresponding to the shape of the structure K was used in the shape of the light absorbing portion and the light transmitting portion in FIG.
(Structure K)
Cross section of light absorbing part: rectangle
Surface shape of light transmissive part: hemispherical surface (observation surface side is convex lens shape)
Radius of curvature of light transmitting part surface r: -30 μm
Light absorption part width w: 10 μm
Light absorption part pitch p: 50 μm
Light absorber height d: 48 μm
Width H of light transmission part: 40 μm.

  The light control members produced as described above are summarized in Table 1 with respect to their shapes and configurations.

r: radius of curvature of light transmitting surface / μm,
d: Height of light absorbing part / μm
p: Pitch of light absorbing part / μm
w: Width of light absorption part / μm
n ₂ : Refractive index of the light transmitting part n ₃ : Refractive index of the light absorbing part.

  The light control member prepared as described above was evaluated for light control function (contrast, screen brightness) and manufacturing stability (molding stability, filling stability). The results are summarized in Table 2.

  From the results in Table 2, it can be seen that the examples of the present invention have both contrast and screen brightness and are excellent in production stability. On the other hand, the comparative example cannot achieve both contrast and screen brightness, and has a problem in manufacturing stability.

The schematic diagram which observed the light beam control member which shows one Embodiment of this invention from the light transmissive direction. The schematic diagram which looked at the light beam control member shown in FIG. 1 from the light transmission direction. The schematic cross section in the AA cross section of the light beam control member shown in FIG. The schematic cross section of the light beam control member (The light absorption part is a trapezoid thing) which shows other embodiment of this invention. The schematic cross section of the light beam control member (a light absorption part is a thing of a triangle) which shows other embodiment of this invention. The schematic cross section which shows each part parameter in the light beam control member of this invention. The schematic cross section of the light beam control member (The light transmissive part and the light absorption part are formed on the base material) which shows other embodiment of this invention. The schematic cross section of the light beam control member (what the refractive index of the light transmissive part becomes low gradually from the center of the observation side surface) which shows other embodiment of this invention. FIG. 6 is a schematic cross-sectional view of a light beam control member (in which an antireflection layer is formed on a concave lens of a light transmission portion) showing another embodiment of the present invention. The schematic schematic diagram of a light transmissive part formation process. The perspective view of the roll 12 in FIG. AA schematic sectional drawing of the roll in FIG. The schematic schematic diagram of a light absorption part formation process. The schematic cross section of the light beam control member in the comparative example 1. FIG. The schematic cross section of the light beam control member in the comparative example 2. FIG. 10 is a schematic cross-sectional view of a light beam control member in Comparative Example 3. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1, 25 Light control member 2 Light absorption part 3 Resin layer 4 Light transmission part 5 Concave lens 6, 8 Base material 7 Antireflection layer 9, 20 Supply apparatus 10 of light transmission part formation material Base to which light transmission part formation material was supplied Material 11, 21 Pressing roll 12 Mold 13, 23 Irradiation device 14, 24 Peeling roll 15, 19 Molding body 16 of light transmitting part 17 Roll 17 Protrusion 18 Protruding part 22 Blade
26 High-refractive part on the observation surface side surface

Claims (7)

  A light control member in which a light absorbing portion and a light transmitting portion are alternately provided in one direction on one surface layer portion, and a surface of the light transmitting portion is recessed from a surface connecting the surfaces of the light absorbing portions. A light beam control member.   The light beam control member according to claim 1, wherein a surface shape of the light transmission portion is a concave lens shape. The light beam control member according to claim 1, wherein a refractive index n ₃ of the light absorbing portion and a refractive index n ₂ of the light transmitting portion are in the following ranges.

The cross-sectional shape of the light absorbing portion is rectangular, trapezoidal, or triangular, the height of the rectangular, trapezoidal, or triangular shape is d, the width of the light transmitting portion is H, the radius of curvature of the surface of the light transmitting portion is r, the light transmission The light control member according to claim 1, wherein when the refractive index of the portion is n ₂ , the height d is in the following range.

The cross-sectional shape of the light absorbing portion is rectangular, trapezoidal, or triangular, and the height d of the rectangular, trapezoidal, or triangular shape, the pitch p of the light transmitting portion, and the width w of the light absorbing portion satisfy the following expressions. The light beam control member according to any one of claims 1 to 4.

  A light control member in which a light absorbing portion and a light transmitting portion are alternately provided in one direction on one surface layer portion, and the refractive index of the light transmitting portion is concentric from the center point of the surface of the light transmitting portion The light beam control member is characterized by being lowered.   At least one layer of a light diffusion layer, an antireflection layer, an antiglare layer, an antistatic layer, a hard coat layer, and an antifouling layer is formed on the surface of the one side of the light beam control member according to any one of claims 1 to 6. A light beam control member formed.

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