JP2001228308A - Off-axis antisotropic light scattering film and biasing photo polymerizable composition to be used for its manufacturing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an off-axis antisotropic light scattering film that by allowing scattering characteristics to have dependency on an angle of incidence, even the scattering directivity with respect to vertical and lateral scattering ranges is easily controlled, storing scattered light is generated a direction most suitable for observation with an off-axis function and the color of display light remains unchanged regardless of a position for the observation. SOLUTION: The biasing photo polymerizable composition containing a photo polymerizable compound with a cationic polymerizable substituent and a photo polymerization initiator generating a Bronsted acid or a Lewis acid is laminated and hardened on an anisotropic light scattering film, with an unhardened or half-hardened resin component forming belt-like light and shade resulting from an uneven refractive index and having an extending direction of the belt-like light and shade inclined to the principal surface of the film in the cross section, and the extending directions of the belt-like light and shape are gradually varied through the film thickness direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light-scattering film having different scattering properties depending on the incident angle of light (or having an incident angle selectivity) and anisotropic light scattering characteristics. The present invention relates to a photopolymerizable composition for deflection capable of exhibiting an off-axis function of generating strong light scattering in a direction different from the incident angle of the light, and an off-axis anisotropic light-scattering film produced using the same.

[0002]

2. Description of the Related Art In a liquid crystal display device, a viewing angle at the time of observation is secured (that is, a display image is brightly displayed on the front surface of the display device), and uniform brightness is provided over the entire display screen. In order to make a display image visible, a light scattering film is arranged on the front of the device.
The language "film" in the present specification means a thin resin sheet, and is used in agreement with the language "sheet". As a conventional light scattering film, a resin film whose surface is processed into a mat shape, a resin film containing a diffusing material inside, and the like are used.

[0003] In the case of a conventional resin film processed into a mat shape or a film containing a diffusing material therein, an incident angle selection function such as a change in scattering depending on the incident angle of incident light, or an incident angle different from the incident angle of incident light. It is difficult in principle to provide an off-axis function of emitting strong scattered light in the direction, and such a function is not actually provided.

In the case of a light-scattering film whose surface is processed into a mat shape, the film surface is physically processed like a sand blaster process to form a mat surface, or the film surface is chemically treated by dissolving with an acidic or alkaline solution. A mat surface is formed. Therefore, it is difficult to control the light scattering property, and it is not possible to change the vertical and horizontal scattering properties.

[0005] In a light-scattering film containing a diffusing material, attempts have been made to control the refractive index, size and shape of the diffusing material in order to control the scattering properties. At present, it is difficult and not enough for practical use.

Accordingly, the above-mentioned light scattering film or screen does not have an incident angle dependency of light scattering or an off-axis function and has no or little directivity of light scattering. The direction of the reflected light from
Unnecessary scattered light in a direction unsuitable for display image observation occurs,
As a result, there is a problem in that the brightness or contrast of display is reduced or a displayed image is blurred.

On the other hand, an invention relating to a reflection type liquid crystal display device using a scattering plate having anisotropy in light scattering is disclosed in Japanese Patent Laid-Open No. 8-2.
No. 01802 is known. The scattering plate disclosed in the above publication is a scattering plate having almost no back-scattering property and strong forward-scattering property, and selectively emits either the incident light to the liquid crystal display device or the output display light from the liquid crystal display device. It has the property of scattering.

[0008] In the above publication, the structure of the scattering plate is not specifically described, but only described as "transparent fine particles hardened with a transparent polymerizable polymer". In such a scattering plate, similarly to the above-mentioned “light scattering film including a diffusing material inside”, even if it has an incident angle selectivity (forward or backward), it differs from the incident angle of the incident light. It is difficult to control the off-axis function of emitting strong scattered light in the direction and the vertical and horizontal scattering characteristics (directivity).

Further, as an invention relating to a transmission type liquid crystal display device using a hologram as a scattering plate, Japanese Patent Laid-Open No. 9-152 is disclosed.
No. 602 is known. The above proposal scatters display light emitted from a liquid crystal display device having a backlight, and employs a hologram as a scattering plate, so that it is easy to give the scattering characteristic an incident angle selectivity, It is easy to control both the vertical and horizontal scattering characteristics, but inevitably involves spectroscopy (wavelength dispersion) due to diffraction phenomena, so that the color of the display light changes to iridescent as the viewing point moves. Will be changed to be visually recognized.

As an invention which has solved these problems, there is Japanese Patent Application No. 10-346743 filed by the present applicant. According to the present invention, a portion having a different refractive index is distributed in an irregular shape and thickness inside a film, thereby forming a light and shade pattern having high and low refractive indices. By optimizing the shape and distribution along the vertical and horizontal directions on the film surface and along the thickness direction of the film, the scattering characteristics depending on the incident angle of the incident light can be changed, and the light in unnecessary directions can be changed. Scattering is eliminated, and light is scattered only in a necessary direction (range). However, in this anisotropic light-scattering film, since the emitted scattered light is strongly scattered at the same angle as the incident angle, when used as a front scattering plate of a reflection type liquid crystal display device, it is strongly scattered in a direction different from the observed direction. Since the light is emitted, the efficiency is slightly lowered.

[0011]

SUMMARY OF THE INVENTION According to the present invention, the scattering characteristic is made dependent on the incident angle, and it is easy to control even the scattering directivity relating to the vertical and horizontal scattering ranges. It is an object of the present invention to provide an off-axis anisotropic light-scattering film that generates strong scattered light in a direction suitable for observation and that does not change the color of display light depending on the observation position.

[0012]

According to the first aspect of the present invention, there is provided a belt-like shading having a high or low refractive index by distributing portions having different refractive indexes in an irregular shape and thickness inside a film. And, in the cross section of the film,
On the uncured or semi-cured anisotropic light-scattering film the resin component in which the direction in which the band-like shading extends is inclined with respect to the main surface of the film, at least one compound (A) having a cationic polymerizable substituent is provided. It contains at least the photopolymerizable compound having the above and (B) a photopolymerization initiator which generates a Bronsted acid or a Lewis acid which activates cationic polymerization by irradiation with ultraviolet light or visible light, and is substantially transparent. Laminate a certain photopolymerizable composition for deflection,
An off-axis anisotropic light-scattering film, wherein the film is cured and the direction in which the band-like shading extends gradually changes in the thickness direction of the film.

[0013] The invention according to claim 2 is characterized in that (A) a photopolymerizable compound having at least one compound having a cationic polymerizable substituent, and (B) a cationic polymerizable compound which is irradiated with ultraviolet light or visible light. It contains at least a photopolymerization initiator that generates a Bronsted acid or Lewis acid that activates, and is capable of swelling an anisotropic light-scattering film that is substantially transparent and has an uncured or semi-cured resin component. This is a photopolymerizable composition for deflection used for producing an off-axis anisotropic light-scattering film.

According to a third aspect of the present invention, there is provided the photopolymerizable composition for deflection for use in producing an off-axis anisotropic light-scattering film according to the second aspect, further comprising a polymer binder. .

[0015]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In an off-axis anisotropic light-scattering film produced using the photopolymerizable composition for deflection of the present invention, portions having different refractive indexes are distributed in an irregular shape and thickness inside the film. As a result, a light and shade pattern having a high and low refractive index is formed, and the size, shape, and distribution of portions having different refractive indexes are optimized along the vertical and horizontal directions on the film surface and along the thickness direction of the film. In addition to the function, the scattering characteristics depending on the incident angle of the incident light are changed, and the strong scattered light is emitted in a direction different from the incident angle, and the light is scattered only in the necessary direction (range). , Light scattering in unnecessary directions is eliminated.

By applying such an off-axis anisotropic light-scattering film, a liquid crystal display device which has high definition, is bright, has high contrast, and is capable of displaying an image with little blur is provided. Further, since the portions having different refractive indices are irregularly distributed when viewed in a plane parallel to the film surface, there is no color change of the emitted light depending on the observation position as seen in the hologram.

The off-axis anisotropic light-scattering film produced by the present invention will be described below with reference to the drawings. FIG. 1 shows an off-axis anisotropic light in which portions having different refractive indices are distributed in an irregular shape and thickness, and a light and shade pattern having high and low refractive indices (represented by black and white in FIG. 1) is formed. It is explanatory drawing which shows the scattering film 1, left is a top view and right is a sectional view. As can be seen from the plan view, the shape of the portion having a different refractive index is horizontally long. Further, as can be seen from the cross-sectional view, the portions having different refractive indices are distributed while being inclined with respect to the thickness direction of the film 1, and the inclination direction is gradually inclined with respect to the film thickness direction. (Angle from the perpendicular).

First, the optical characteristics of the off-axis light-scattering film 1 shown in FIG. An angle (along the film 1) substantially along the above-mentioned inclination direction in which portions having different refractive indexes are distributed.
(In the direction of the arrow 3 in the figure) forming an angle θ from the perpendicular to the light beam, light scattering occurs. At this time,
The direction of inclination of the portion having a different refractive index gradually changes in the thickness direction of the film 1, and light scattering occurs strongly in a direction along the direction, so that the scattered light emitted from the film 1 is different from the incident angle of the incident light. It spreads around the direction (direction of arrow 4 in the figure). For light incident at an angle substantially perpendicular to the above-mentioned inclination direction (direction of arrow 5 in the figure), it functions as a mere transparent film, and the incident light is emitted without being scattered.

Next, considering a plan view, portions having different refractive indices are irregularly distributed when viewed in a plane parallel to the film surface, and thus do not have the regularity of a hologram. No chromatic dispersion caused by Therefore, according to the light scattering film of the present invention, the color of the emitted light does not change depending on the observation position, and an ideal white color is obtained.

When the shape of a portion having a different refractive index is vertically long (or horizontally long), when light incident on the portion is scattered and emitted, the light scattering characteristic of the light emitted from each portion is horizontally long (or long). Or, it has directivity such that it is vertically long. In FIG. 1, the emitted light is scattered vertically because the shape is horizontally long.

FIG. 2 is a graph showing an example of the incident angle dependence of the off-axis anisotropic light-scattering film 1 produced using the photopolymerizable composition for deflection of the present invention. As shown by a solid line 5 in the figure, a specific incident angle range (0 degree to 6 degrees in the figure)
0 degree), the haze value is 80% or more, and conversely, the haze value is 20% or less for light having a symmetrical incident angle (from -60 degrees to 0 degrees in the figure). This indicates the scattering angle dependency referred to in this specification.

FIG. 3 is a graph showing an example of the off-axis function of the off-axis anisotropic light-scattering film 1 produced using the photopolymerizable composition for deflection of the present invention. This figure shows that the illumination light is emitted when the incident light enters the off-axis anisotropic light-scattering film 1 manufactured at the present invention at an incident angle of 30 degrees (an example of the angle at which the haze value is 80% or more in FIG. 2). 3 shows the intensity distribution of scattered light. As shown in the figure, the strongest scattered light is generated in the direction of the emission angle of 10 degrees. That is, the optical axis is shifted in a direction different from the incident angle of 30 degrees, and this indicates the off-axis function referred to in this specification.

Further, as described above, if the shape of the portion having a different refractive index on the film surface is horizontally long (or vertically long), when light incident on the portion is scattered and emitted, the light is reflected from each portion. Has a directivity such that the light scattering characteristic of the outgoing light becomes vertically long (or horizontally long). For example, if the shape is horizontally long as shown in FIG. 1, the scattered outgoing light from the light scattering film has a distribution that becomes a vertically long ellipse as shown in FIG.

Next, the structure of the off-axis anisotropic light-scattering film 1 produced in the present invention will be described in more detail. As described above, in the off-axis anisotropic light-scattering film 1 produced in the present invention, a portion having a different refractive index is distributed in an irregular shape / thickness, thereby forming a light and shade pattern having a high and low refractive index. Are formed. If the difference in the refractive index is too small, the scattering property is deteriorated. Conversely, if the difference is too large, light scattering occurs regardless of the incident angle of the light. It becomes difficult to have. Therefore, light scattering does not occur only by the refractive index difference on the surface, and the film 1 needs to have an optimal refractive index difference such that the film 1 has a sufficient scattering property due to its thickness.

In the present invention, the refractive index difference is appropriately selected from the range of 0.001 to 0.2 so that the above condition is satisfied.
It is appropriately selected in the range of 0 μm to 1 μm.

Since the refractive index difference that can be recorded is limited by the preparation method and the recording material, the film is thinned when the refractive index difference is large, and thickened when the refractive index difference is small. Can be realized. In addition, the inclination angle in the film thickness direction of the portion having a different refractive index differs depending on the application to which the light-scattering film of the present invention is applied. For example, the front scattering plate for a reflective liquid crystal display device shown in FIG. Take
It scatters light incident from the perpendicular direction (0-degree direction) to the 60-degree direction (overhead of the observer) of the display device, and conversely converts the light into light from the perpendicular direction to -60 degrees (the observer's foot direction). On the other hand, a function that does not cause scattering is considered to be desirable. For this reason, it is necessary to generate light scattering most efficiently with respect to light having an incident angle of 30 degrees (obliquely upward). In this example, in consideration of refraction of light at the film interface, the front surface of the film is considered. At the periphery, the inclination angle is distributed at an angle of about 19 degrees from the direction perpendicular to the film.

Next, in order to realize the off-axis function as shown in FIG. 3, the light scattering film of the present invention has a structure in which the inclination angle is gradually changed in the thickness direction of the film. ing.

For example, taking the same front scattering plate for a reflection type liquid crystal display device as shown in FIG. 5 as described above, the liquid crystal display device is approximately -20 degrees from the perpendicular direction (0 degrees direction = front). Between the front of the device)
As described above, light incident at an incident angle of 30 degrees is -10.
It is desirable to shift the optical axis in the degree direction. Therefore, 30
The structure is such that the angle of inclination of the portion having a different refractive index with respect to the film thickness direction is gradually changed so that the incident light from the degree direction is scattered about the -10 degree direction. In this example, in consideration of the refraction of light at the film interface, the inclination angle is inclined at about 19 degrees from the perpendicular direction near the film surface as described above, and gradually inclined toward the film back surface from there. Is small, and the structure is inclined about 6.5 degrees in the vicinity of the back surface of the film.

The size of the portions having different refractive indices is random and non-regular in order to cause light scattering, but in order to have necessary scattering properties, the average size is 0.1 mm in diameter.
It is appropriately selected from the range of 1 μm to 300 μm according to the scattering property required for each application. Further, in order to impart directivity to light scattering, the average size is made different between the longitudinal direction and the lateral direction of the film. As an example, in order to cause light scattering in the shape of an ellipse extending in the vertical direction, the average size in the vertical direction is 12 μm, but the average size in the horizontal direction is 50 μm. A light scattering film having a scattering directivity of ± 40 degrees and a lateral direction of about ± 10 degrees can be obtained.

Although the off-axis anisotropic light-scattering film 1 produced in the present invention is a resin layer having a structure as described in claim 1, it has been described in this specification in a unified manner in the language of film. For example, a sheet formed on a hard substrate such as a glass substrate or a resin substrate may be used.

The means for producing the off-axis anisotropic light scattering film of the present invention will be described below. Inside the film of the present invention, a portion having a different refractive index is distributed in an irregular shape / thickness, thereby forming a light and shade pattern having a high or low refractive index, and the portion having a different refractive index is a film. The anisotropic light-scattering film having a structure in which the film is distributed in a layered manner with respect to the thickness direction can be produced by optical exposure means.

FIG. 6 shows that a light and shade pattern having a high and low refractive index is formed by distributing portions having different refractive indexes in an irregular shape and thickness inside the film. It is explanatory drawing which shows an example of the optical system which manufactures the anisotropic light-scattering film which is a structure in which the part was inclined with respect to the film thickness direction and distributed in layered form using a speckle pattern. A ground glass 17 is irradiated with laser light 16 emitted from a laser light source 15. A predetermined distance F is provided on the surface of the ground glass 17 opposite to the laser irradiation side.
Then, the photosensitive material 20 is disposed, and the photosensitive material 20 is exposed and irradiated with a speckle pattern which is a complicated interference pattern created by the laser light transmitted and scattered by the frosted glass 17.

At this time, since the laser beam 16 and the photosensitive material 20 are arranged at a predetermined angle α as shown in the figure, the speckle pattern is exposed at a predetermined angle in the photosensitive material. Since this angle corresponds to the inclination of a portion having a different refractive index in the anisotropic light scattering film (that is, the scattering peak angle θ depending on the incident angle), the angle is about 0 to 60 degrees depending on the application. Is appropriately selected within the range. As a matter of course, the inclination of the portion having a different refractive index in the anisotropic light-scattering film and the scattering peak angle θ depending on the incident angle are different angles because light refraction occurs at the film interface. Laser light 16
The angle of inclination α between the light-sensitive material and the light-sensitive material 20 and the scattering peak angle θ depending on the incident angle also depend on the light-sensitive material used.
It may vary depending on processing steps such as development.

The laser light source 15 used for recording can be appropriately selected from the wavelengths of 514.5 nm, 488 nm and 457.9 nm of an argon ion laser depending on the sensitivity of the photosensitive material. In addition, other than the argon ion laser, any laser light source having good coherence can be used. For example, a helium neon laser or a krypton ion laser can be used.

The photosensitive material 20 used here is a photosensitive material that can be recorded in the form of a change in the refractive index between a portion exposed to a laser beam and an unexposed portion, and has a higher resolving power than a light and shade pattern to be recorded. The material must be capable of recording a pattern in the direction of its thickness.

As such a recording material, a bisphenol A type epoxy resin or a brominated bisphenol A type epoxy resin (A) described in Japanese Patent Application No. 11-255453, filed by the present applicant, and at least one in the molecule A compound (B) having one oxirane ring, a compound (C) having a lower refractive index than the above (A) and (B) and having radical polymerizability, and a light generating a cationic species and a radical species by actinic radiation Composition for anisotropic light-scattering film containing initiator (D), Japanese Patent Application No. 11-25545
No.4 bisphenol A type epoxy resin or brominated bisphenol A type epoxy resin (A), which has radical polymerizability or cationic polymerizability and has (meth)
A compound (B) having an ethylenically unsaturated bond excluding an acryloyl group, and an aliphatic compound having a lower refractive index than the above (A) and (B) and having at least one (meth) acryloyl group in a molecule ( C) and a photoinitiator (D) for generating a cationic species and a radical species by actinic radiation;
No. 255455, bisphenol A type epoxy resin or brominated bisphenol A type epoxy resin (A)
And a non-reactive compound (B) having a molecular weight of 2,000 or less and a radical polymerizability having a lower refractive index than those of the compounds (A) and (B). For an anisotropic light-scattering film, comprising a compound (C) having a compound (C) and a photoinitiator (D) that generates a cationic species and a radical species by actinic radiation, Japanese Patent Application No. 11-1085.
No. 73, comprising (A) a compound having cationic polymerizability, (B) a compound having radical polymerizability, (C) a photoinitiator which generates a cationic species and a radical species by actinic radiation, Composition for an anisotropic light-scattering film having a difference in refractive index between a compound having polymerizability and (B) a compound having radical polymerizability, Japanese Patent Application No. 11-1
No. 08574, a composition for an anisotropic light-scattering film comprising a plurality of compounds having at least one polymerizable ethylenic double bond having a difference in refractive index in a molecule, Japanese Patent Application No. 11-1.
No. 08575, a composition for an anisotropic light-scattering film having a plurality of compounds having a polymerizable cationic polymerizable substituent having a difference in refractive index, and (A) polymerizable ethylene described in Japanese Patent Application No. 11-108576. And (B) a compound having no polymerizable ethylenic double bond in the molecule, and (A) a polymerizable ethylenic double bond in the molecule. A composition for an anisotropic light-scattering film in which the compound having one or more compounds and (B) a compound having no polymerizable ethylenic double bond have different refractive indices, a plurality of (A) compounds described in Japanese Patent Application No. 11-108577.
(A) a compound having at least one oxirane ring in the molecule, (B) a compound having radical polymerizability, and (C) a photoinitiator that generates a cationic species and a radical species by actinic radiation. A composition for an anisotropic light scattering film having a difference in the refractive index between a compound having at least one oxirane ring and (B) a compound having radical polymerizability can be used, and a photosensitive material for a volume hologram can also be used.

The speckle pattern is a bright and dark spot pattern generated when light having good coherence is scattered and reflected or transmitted by a rough surface, and light scattered by minute irregularities on the rough surface interferes in an irregular phase relationship. It is caused by

Description of "Light Measurement Handbook, Asakura Shoten, written by Toshiharu Tada et al., Published on November 25, 1994" (p.
266-p. According to 268), in a speckle pattern in which the density and phase show random values depending on the position, the size of the pattern is inversely proportional to the angle at which the diffusion plate is viewed from the photosensitive material, and the average diameter of the pattern is determined. Is done. Therefore, when the size of the diffusion plate is made larger in the vertical direction than in the horizontal direction, the pattern recorded on the photosensitive material is finer in the vertical direction than in the horizontal direction.

In the speckle pattern according to the manufacturing method using the optical system shown in FIG. 6, the wavelength λ of the laser beam 16 to be used, the size D of the frosted glass 17, and the distance F between the frosted glass 17 and the photosensitive material 20 are recorded. The average size d of the pattern is determined. Generally, d is expressed by the following equation.

D = 1.2λF / D

The average length t of this speckle pattern in the depth direction is expressed by the following equation.

T = 4.0λ (F / D) ²

As described above, an anisotropic light-scattering film having a desired three-dimensional refractive index distribution can be obtained by optimizing the values of λ and F / D so as to have optimum scattering properties.

As an example, when λ = 0.5 μm, F / D =
Assuming that 2, d = 1.2 μm and t = 8 μm, the light and shade pattern on the film surface is distributed at an average of 1.2 μm, and the thickness direction of the film has an average of 8 μm in a direction according to the inclination angle. Will be distributed.

However, these sizes are merely average sizes. Actually, the sizes are variously large and small with respect to these sizes, and portions having different refractive indexes are inclined on the surface and in the depth direction. Will be distributed.

In order to swell the anisotropic scattering film with the photopolymerizable composition for deflection described later and to gradually change the direction in which the band-like shading extends in the thickness direction of the film, the photopolymerization composition for deflection is used. The resin component of the anisotropic light-scattering film before laminating and curing the conductive composition needs to be uncured or semi-cured. In the present specification, the term “uncured or semi-cured” refers to a state where polymerization and crosslinking are not completely completed.

In the anisotropic light-scattering film produced by the above-described producing means, portions having different refractive indexes are distributed in principle at the same inclination angle φ in the thickness direction of the film (FIG. 7).
a) Therefore, means for gradually changing the inclination angle in the thickness direction of the film to realize the off-axis anisotropic light-scattering film of the present invention will be described below.

In order to change the inclination angle φ of a portion having a different refractive index, the film thickness L of the anisotropic light-scattering film is changed. This is because increasing the film thickness L of the anisotropic light scattering film recorded at the same inclination angle φ as shown in FIG. 7a to L ′ as shown in FIG.
This is done using the principle that the tilt angle φ changes accordingly to φ ′.

More specifically, as shown in FIG. 7C, if there is little change in thickness near the front surface of the film (near X in the figure) and large change in thickness near the back surface of the film (near Y in the figure), 2, the off-axis anisotropic light-scattering film 1 can be realized.

The off-axis anisotropic light-scattering film utilizes the fact that the (A) photopolymerizable compound which can swell the anisotropic light-scattering film penetrates into the anisotropic light-scattering film and swells the produced light and shade pattern of refractive index. It was done. Furthermore,
It is a photopolymerizable composition for deflection that converts the light scattering property of the anisotropic light scattering film with good reproducibility by curing the compound that has penetrated. The photopolymerizable compound (A) preferably contains at least one compound having a cationically polymerizable substituent. In addition, solid (A)
When a photopolymerizable compound is used, it may be used in combination with the liquid (A) photopolymerizable compound that dissolves the compound.
(A) The photopolymerizable compound is one or two of the compounds shown below.
Two or more may be used in combination.

Specifically, it comprises one or a mixture of two or more of an epoxy compound, a cyclic ether compound, a cyclic lactone compound, a cyclic carbonate compound, a cyclic acetal compound, a cyclic sulfide compound, a vinyl compound and the like. Among such compounds having cationic polymerizability, a compound having at least one epoxy group in one molecule is preferable, and examples thereof include an aromatic epoxy compound and an alicyclic epoxy compound.

Preferred as the aromatic epoxy compound is a polyglycidyl ether of a polyhydric phenol having at least one aromatic ring or an alkylene oxide adduct thereof, such as bisphenol A or an alkylene oxide adduct thereof and epichlorohydrin. Glycidyl ethers and epoxy novolak compounds produced by the reaction are mentioned. Bisphenol A, bisphenol AD, bisphenol B, bisphenol AF, bisphenol S, brominated bisphenol A,
Examples include epoxy compounds produced by a condensation reaction of various phenol compounds such as novolak, o-cresol novolak, and p-alkylphenol novolak with epichlorohydrin.

Typical examples of the alicyclic epoxy compound include:
1,2,7,8-diepoxyoctane or 3,4
Alicyclic epoxy compounds having an epoxy group or an epoxycyclohexyl group such as -epoxycyclohexylmethyl-3 ', 4'-epoxycyclohexanecarboxylate, produced by the reaction of the above bisphenol A or an alkylene oxide adduct thereof with epichlorohydrin; Hydrogenated glycidyl ethers, particularly hydrogenated bisphenol A, hydrogenated bisphenol AD,
Examples include hydrogenated bisphenol B, hydrogenated bisphenol AF, hydrogenated bisphenol S, hydrogenated brominated bisphenol A, and the like.

Examples of other compounds having an epoxy group include (poly) glycidyl ether, glycidyl acrylate and glycidyl methacrylate of aliphatic polyhydric alcohol or its alkylene oxide adduct. Diglycidyl ether of 1,4-butanediol, diglycidyl ether of 1,6-hexanediol, triglycidyl ether of glycerin, triglycidyl ether of trimethylolpropane, diglycidyl ether of (di, tri, poly) ethylene glycol, ( Di, tri, poly) propylene glycol diglycidyl ether and the like.

Examples of the compound having a cationic polymerizable substituent other than the epoxy group include trimethylene oxide,
Oxetane compounds such as 3,3-dimethyloxetane and 3,3-dichloromethyloxetane; oxolan compounds such as tetrahydrofuran and 2,3-dimethyltetrahydrofuran; 1,3,5-trioxane; 1,3-dioxolan; Cyclic acetal compounds such as 2,6-trioxanecyclooctane, cyclic lactone compounds such as β-propiolactone and ε-caprolactone,
1,3-dioxan-2-one, 5-methylene-1,3
Cyclic carbonate compounds such as -dioxan-2-one, ethylene sulfide, 1,2-propylene sulfide, thioepichlorohydrin, cyclic sulfide compounds such as 3,3-dimethylthiethane, ethylene glycol divinyl ether, polyalkylene Examples include vinyl ether compounds such as glycol divinyl ether and alkyl vinyl ether, ethylenically unsaturated compounds such as vinyl cyclohexane, isobutylene and polybutadiene, and derivatives of the above compounds.

Specifically, diglycerol polyglycidyl ether, pentaerythritol polyglycidyl ether, 1,4-bis (2,3-epoxypropoxyperfluoroisopropyl) cyclohexane, sorbitol polyglycidyl ether, trimethylolpropane polyglycidyl ether, 1,6-hexanediol diglycidyl ether, resorcin diglycidyl ether, polyethylene glycol diglycidyl ether, phenyl glycidyl ether, p-tert-butylphenyl glycidyl ether, diglycidyl adipate,
Orthophthalic acid diglycidyl ester, dibromophenyl glycidyl ether, dibromoneopentyl glycol diglycidyl ether, 1,6-dimethylol perfluorohexane diglycidyl ether, 4,4'-bis (2,3-epoxypropoxy perfluoroisopropyl) diphenyl ether , 1,2,5,6-diepoxy-4,7-methanoperhydroindene, 2- (3,4-
Epoxycyclohexyl) -3 ', 4'-epoxy-
1,3-dioxane-5-spirocyclohexane, 1,
2-ethylenedioxy-bis (3,4-epoxycyclohexylmethane), 4 ', 5'-epoxy-2'-methylcyclohexylmethyl-4,5-epoxy-2-methylcyclohexanecarboxylate, ethylene glycol-bis ( 3,4-epoxycyclohexanecarboxylate), bis- (3,4-epoxycyclohexylmethyl) adipate, di-2,3-epoxycyclopentyl ether, vinyl-2-chloroethyl ether, vinyl-n-butyl ether, triethylene Glycol divinyl ether, 1,4-cyclohexanemethanol divinyl ether, trimethylol methane trivinyl ether vinyl glycidyl ether, araldite CY175
(Trade name of Ciba-Geigy Corporation), Araldite CY1
77 (trade name, manufactured by Ciba Geigy), Araldite C
Y179 (trade name, manufactured by Ciba-Geigy Corporation), Araldite CY184 (trade name, manufactured by Ciba-Geigy Corporation), Araldite CY192 (trade name, manufactured by Ciba-Geigy Corporation), Celoxite 3000 (trade name, manufactured by Daicel Chemical Co., Ltd.) and the like Mixtures are mentioned.

(B) The photopolymerization initiator comprises one or more compounds generating a Bronsted acid or a Lewis acid which activates cationic polymerization by irradiation with ultraviolet light or visible light. And As such a photopolymerization initiator, J. Pharm. Photo
chem. Sci. Technol. , 2,283 (1
987). Compounds described in, specifically, iron arene complex, trihalogenomethyl-substituted s-triazine, sulfonium salt, diazonium salt, phosphonium salt, selenonium salt, arsonium salt, iodonium salt and the like, and as the iodonium salt Is Macromo
recules, 10, 1307 (1977). And the like, for example, diphenyliodonium, ditolyliodonium, phenyl (p-anisyl) iodonium, bis (m-nitrophenyl) iodonium, bis (p-tert-butylphenyl) iodonium, bis (p-chlorophenyl) iodonium and the like And iodonium chloride, bromide or borofluoride salt, hexafluorophosphate salt, hexafluoroarsenate salt, hexafluoroantimonate salt, aromatic sulfonate and the like.

These photopolymerizable compositions for deflection may be diluted with an appropriate solvent if necessary. In such a case, drying is necessary after coating on an anisotropic light scattering film or a substrate. Examples of the solvent include dichloromethane, chloroform, acetone, 2-butanone, cyclohexanone, ethyl acetate, 2-methoxyethanol, 2-ethoxyethanol, 2-butoxyethanol, 2-ethoxyethyl acetate, 2-butoxyethyl acetate,
-Methoxyethyl ether, 2-ethoxyethyl ether, 2- (2-ethoxyethoxy) ethanol, 2-
(2-butoxyethoxy) ethanol, 2- (2-ethoxyethoxy) ethyl acetate, 2- (2-butoxyethoxy) ethyl acetate, tetrahydrofuran,
1,4-dioxane and the like can be mentioned.

The photopolymerizable composition for deflection according to claim 2 or 3 may further contain a known polymer binder, a silane coupling agent, a plasticizer, a polymerization inhibitor, a chain transfer agent, an oxidizing agent, if necessary. Various additives such as an inhibitor, a leveling agent and an antifoaming agent may be added. The polymer binder is used for improving the film-forming property, the uniformity of the film thickness, the storage stability and the like of the photopolymerizable composition for deflection. The polymer binder may be any one having good compatibility with the photopolymerizable compound and the photopolymerization initiator, and specific examples thereof include polystyrene, chlorinated polyethylene, polymethyl methacrylate, methyl methacrylate and other (meth) acrylic. Acid alkyl ester copolymer, vinyl chloride and acrylonitrile copolymer, polyvinyl acetate, polyvinyl alcohol, polyvinyl formal, polyvinyl butyral, polyvinyl pyrrolidone, ethyl cellulose, acetyl cellulose, phenoxy resin, and the like, but are not limited thereto. Not something. These may be used alone or in combination of two or more.

The components (A) and (B) are appropriately selected, and the photopolymerizable composition for deflection obtained by mixing at an arbitrary ratio is coated on the anisotropic light-scattering film by a spin coater, a roll coater, or the like.
Coating using a known coating means such as a bar coater, or applying the photopolymerizable composition for deflection on a glass substrate or a film base material such as polyethylene terephthalate (PET), polyprorylene (PP), polycarbonate (PC), etc. Laminated on the anisotropic light-scattering film coated using a known coating means, and left for a sufficient time,
The entire surface is exposed to ultraviolet light or visible light, and fixed. At this time, the heat treatment may be performed simultaneously or sequentially.

Means for coating or laminating the photopolymerizable composition for deflection on the anisotropic light-scattering film and fixing the same include high-pressure mercury lamps, low-pressure mercury lamps, xenon lamps, carbon arc lamps, ultrahigh-pressure mercury lamps, metal halide lamps and the like. There is, but not limited to, overall exposure. Heating with an oven or a hot plate may be performed simultaneously or sequentially.

Hereinafter, embodiments of the present invention will be described with reference to specific examples.

Example 1 100 parts by weight of bisphenol A type epoxy oligomer (Epicoat 1001, trade name of Yuka Shell Epoxy Co., Ltd.), 4,4'-bis (te
A solution was prepared by mixing and dissolving 5.0 parts by weight of (rt-butylphenyl) iodonium hexafluorophosphate in 100 parts by weight of 2-butanone. The photosensitive solution is made of PET
A film (Lumirror S-10, trade name, manufactured by Toray Industries, Inc.) was applied with a bar coater # 16 and dried to obtain a photopolymerizable composition for deflection.

As a material for the anisotropic light scattering film, 100 parts by weight of a bisphenol A type epoxy resin (Epicoat 1007, trade name of Yuka Shell Epoxy Co., Ltd.), tripropylene glycol diacrylate (VISCOAT)
-310HP, trade name of Osaka Organic Chemical Co., Ltd.) 50 parts by weight, glycidyl phenyl ether 30 parts by weight, and 4,4′-bis (tert-butylphenyl) iodonium hexafluorophosphate 5.0 parts by weight,
A photosensitive solution was prepared by mixing and dissolving 0.2 part by weight of 4'-bis (diethylamino) benzophenone in 100 parts by weight of 2-butanone. The photosensitive solution was transferred to a blue plate glass (1.1 mm thick,
(5 inch square) with a doctor blade so as to have a film thickness of about 30 μm, and dried to obtain a recording medium. The anisotropic light-scattering film is recorded by exposing the photosensitive material from the surface of the photosensitive material through the frosted glass 15 by using a light obtained by spreading a krypton ion laser (413 nm) as a light source using a lens with the optical system shown in FIG. (Inclination angle 19
Every time). The photopolymerizable composition for deflection was laminated on the semi-cured anisotropic light-scattering film, heated at 85 ° C. for 5 minutes, and then cured and fixed by irradiating the entire surface with a high-pressure mercury lamp. Furthermore, an off-axis anisotropic light-scattering film was obtained by peeling the cured product from the PET film and the glass substrate. The thickness of the film obtained was 40 microns.

The scattering intensity and scattered light emission angle of the obtained off-axis anisotropic light scattering film were measured as follows. The measurement conditions were as follows: a white light with a width of 3 mm was incident on the sample at an angle of 30 °, and a photomultimeter having a slit with a width of 3 mm and placed on a circumference with a radius of 20 cm around the sample was placed on the circumference of the sample. While scanning, the intensity of the scattered light from the sample and its scattering angle were detected. Table 1 shows the results.

[0066]

[Table 1]

Example 2 As the photopolymerizable composition for deflection in Example 1, 100 parts by weight of a bisphenol A type epoxy oligomer (Epicoat 1001, trade name of Yuka Shell Epoxy Co., Ltd.), tripropylene glycol divinyl ether (Rapicure DVE-3, ISP
10 parts by weight of Japan Co., Ltd.), 5.0 parts by weight of 4,4′-bis (tert-butylphenyl) iodonium hexafluorophosphate, and 2-butanone 100
The mixture was dissolved in parts by weight to obtain a photosensitive liquid, and the same operation as in Example 1 was performed to prepare an off-axis anisotropic light-scattering film. Table 2 shows the measurement results.

[0068]

[Table 2]

<Examples 3 to 6> Instead of tripropylene glycol divinyl ether in the photopolymerizable composition for deflection in Example 2, a bisphenol A type epoxy oligomer (Epicoat 828, a product of Yuka Shell Epoxy Co., Ltd.) Alicyclic epoxy monomer (araldite CY17)
9, Ciba-Geigy Co., Ltd.), 3-ethyl-3-
The same operation as in Example 2 was performed using hydroxymethyloxetane (EOXA, trade name, manufactured by Toa Gosei Chemical Co., Ltd.) and brominated bisphenol-based epoxy resin (araldite 8049SP, trade name, manufactured by Ciba Geigy Co., Ltd.) An anisotropic light scattering film was prepared. Table 3 shows the measurement results.

[0070]

[Table 3]

<Examples 7 to 10> Bisphenol A type epoxy oligomer (Epicoat 1001, Yuka Shell Epoxy Co., Ltd.) in the photopolymerizable composition for deflection in Examples 3 to 6
100 parts by weight of an acrylic resin (Dianal BR-90, trade name of Mitsubishi Rayon Co., Ltd.) was added as a polymer binder instead of (trade name of trade name), and the same operation as in Examples 3 to 6 was performed. An off-axis anisotropic light-scattering film was produced.
Table 4 shows the measurement results.

[0072]

[Table 4]

Example 11 The photopolymerizable composition described in Example 1 was used as a photopolymerizable composition for deflection. As a material for the anisotropic light-scattering film, 100 parts by weight of bisphenol-based epoxy acrylate (Lipoxy VR60, trade name of Showa Polymer Co., Ltd.), tripropylene glycol diacrylate (VISCOAT-310HP, trade name of Osaka Organic Chemical Co., Ltd.) 50 parts by weight and 3,3 ', 4,4'-
7.5 parts by weight of tetra (tert-butylperoxycarbonyl) benzophenone and 0.25 parts by weight of 3,3′-carbonylbis (7-diethylaminocoumarin) in 2-
What was mixed and dissolved in 100 parts by weight of butanone was used as a photosensitive solution. The photosensitive liquid was applied to a blue plate glass (1.1 mm thick, 5 inch square) with a doctor blade so as to have a film thickness of about 70 μm, and dried to obtain a recording medium. The anisotropic light-scattering film is recorded by exposing the photosensitive material from the surface of the photosensitive material through the frosted glass 15 with light obtained by spreading an argon ion laser (488 nm) as a light source using a lens with the optical system shown in FIG. (Inclination angle 19 degrees). The photopolymerizable composition for deflection was laminated on the semi-cured anisotropic light-scattering film, heated at 85 ° C. for 5 minutes, and cured and fixed by irradiating the entire surface with a high-pressure mercury lamp. Furthermore, an off-axis anisotropic light-scattering film was obtained by peeling the cured product from the PET film and the glass substrate. The resulting film had a thickness of 79 microns. Table 5 shows the measurement results.

[0074]

[Table 5]

[0075]

According to the present invention, light is scattered with respect to light incident on the anisotropic light-scattering film within a predetermined angle range. It has angle selectivity, and when light is incident at an angle where light scattering occurs, it generates strong scattered light in a direction different from the incident angle, so that light that needs scattering and light that does not need scattering are It can be separated by the angle of incidence on the film, and can deflect the required scattered light in the desired direction. As a result, when used in a display device, etc., it can be displayed in front of the device without unnecessary scattering. This has the effect of improving the brightness, fineness, visibility, and contrast of images, and reducing the blur of the displayed image.

Since the portions having different refractive indices are irregularly distributed when viewed in a plane parallel to the film surface, there is no change in the color of the emitted light depending on the observation position as seen in the hologram. In addition, when light is incident at an incident angle at which light scattering occurs, it is possible to also have a scattering directivity in which the spread of the scattered light differs vertically and horizontally. for that reason,
The scattered light can be emitted only in a necessary direction, and as a result, when used in a display device, there is an effect that the display brightness and contrast are improved without generating unnecessary scattering.

[0077]

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an off-axis anisotropic light-scattering film 1 produced in the present invention, wherein the left is a plan view and the right is a cross-sectional view.

FIG. 2 is a graph showing an example of the incident angle dependency of the off-axis anisotropic light-scattering film 1 produced in the present invention.

FIG. 3 is a graph showing an example of an emitted light intensity distribution for explaining an off-axis function of the off-axis anisotropic light-scattering film 1 produced in the present invention.

FIG. 4 is a diagram illustrating the directivity of light scattering of an off-axis anisotropic light-scattering film produced according to the present invention.

FIG. 5 is a cross-sectional view conceptually showing a main part of a reflective liquid crystal display device using an off-axis anisotropic light scattering film manufactured in the present invention.

FIG. 6 is an explanatory diagram showing an example of an optical system for producing an anisotropic light scattering film using a speckle pattern.

FIG. 7 is an explanatory view conceptually showing a production means for imparting an off-axis function to an anisotropic light-scattering film in the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Off-axis anisotropic light-scattering film 2 ... Deflection photopolymerizable composition 3 ... Illumination light incident from a scattering direction 4 ... Emission scattered light from an anisotropic light-scattering film 5 ... Illumination light incident from a transmission direction 6 ... Actually measured Plot of haze value 7 ... Liquid crystal panel 8 ... Reflector 9 ... Ambient illumination light 10 ... Scattered light 11 ... Emitted scattered light 12 ... Liquid crystal panel front glass plate 13 ... Liquid crystal layer 14 ... Liquid crystal panel rear glass plate 15 ... Laser light source 16 ... Laser light 17 ... ground glass 18 ... beam expander 19 ... collimator 20 ... photosensitive material

Claims (3)

[Claims] 1. A belt-like shading having a high or low refractive index is formed by distributing portions having different refractive indexes in an irregular shape and thickness inside a film. On the uncured or semi-cured anisotropic light-scattering film, the resin component in which the direction of extension of the band-like shading is inclined with respect to the main surface of the film is provided with at least one compound (A) having a cationic polymerizable substituent. And (B) a photopolymerization compound that generates a Bronsted acid or a Lewis acid that activates cationic polymerization by irradiating ultraviolet light or visible light, and is substantially transparent. Off-axis anisotropic characterized in that the photopolymerizable composition for deflection is laminated and cured, and the direction in which the band-like shading extends gradually changes in the thickness direction of the film. Light scattering film. (A) a photopolymerizable compound having at least one compound having a cationically polymerizable substituent,
(B) at least a photopolymerization initiator that generates a Bronsted acid or Lewis acid that activates cationic polymerization by irradiation with ultraviolet light or visible light, is substantially transparent, and has no resin component. A photopolymerizable composition for deflection used in the production of an off-axis anisotropic light-scattering film, which is capable of swelling a cured or semi-cured anisotropic light-scattering film. 3. The photopolymerizable composition for deflection used for producing an off-axis anisotropic light-scattering film according to claim 2, further comprising a polymer binder.