JP2000258612A - Light scattering sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To ensure function to scatter light forward and such superior visibility as to cause no image blurring by providing a layer having a function to scatter light forward formed by dispersing organic fine particles and/or inorganic fine particles in a transparent resin base. SOLUTION: The light forward scattering layer 2a is formed by dispersing organic fine particles and/or inorganic fine particles 7b in a transparent resin base 7a comprising cellulose acetate resin or the like and light passing through the layer 2a is scattered forward. The enhancement of visibility due to increase of forward scattering intensity, the decrease of backward scattering intensity and the suppression of the occurrence of image blurring is achieved in a well- balanced state by adjusting the entire light transmittance and haze of the light forward scattering layer 2a and a bright high-contrast image is obtained. Since the light scattering sheet 2 acts also as a protective coat 2d of a polarizing layer 2c, the occurrence of image blurring is further prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a liquid crystal display device, and more particularly to a light scattering sheet having a light forward scattering function used for a reflection type liquid crystal display device.

[0002]

2. Description of the Related Art Conventionally, a liquid crystal display device is a personal computer,
It has been used for display in word processors, LCD televisions, clocks, calculators and the like. In recent years, the development of information and communication infrastructure such as the Internet and the networking of information through the fusion of computers and communication devices have advanced, and access to information is no longer restricted by time and place due to this networking. Indispensable for using the network is the PDA (Person
It is a mobile information terminal typified by nal digital assistance, etc., and a thin and lightweight mobile personal computer more than a current notebook personal computer. Considering portability, these devices need to be driven for a long time by a battery and to be thin and compact. Therefore, the liquid crystal display devices required for these devices are thin, lightweight, and low power consumption. In order to meet these requirements, a reflection type liquid crystal display device is regarded as the most promising.

Further, in order to cope with the diversification of information accompanying the advance of multimedia in the future, colorization and high definition are important, but in order to realize this, a single polarizing plate is required. A reflective liquid crystal display device having one polarizing layer used is advantageous. Among reflection type liquid crystal display devices having one polarizing layer, particularly, the liquid crystal layer is formed of HAN (Hybrid Align).
(Needmatic) oriented R-OCB (Re
flexible Optically Compen
(Saturated Bend) type liquid crystal display devices have excellent characteristics such as low voltage, wide viewing angle, high-speed response, halftone display, and wide contrast, but require a light forward scattering functional layer. There is a problem that an image is easily blurred.

[0004]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a reflection type liquid crystal display device, in particular, an R-O having a liquid crystal layer having a HAN orientation.
A CB-type liquid crystal display device having a light forward scattering function,
Another object of the present invention is to provide a light-scattering sheet excellent in visibility that does not cause image blur.

[0005]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have conducted a series of studies and found that a light forward scattering function in which organic fine particles and inorganic fine particles are dispersed in a transparent resin base. The layer, in particular, its optical properties, and the composition ratio of the composition are within a specific range, and found that a remarkable improvement in the forward scattering function and visibility when incorporated in a reflective liquid crystal display device is found. Reached.

That is, the present invention provides a transparent resin base comprising:
An object of the present invention is to provide a light scattering sheet having a light forward scattering functional layer in which organic fine particles and / or inorganic fine particles are dispersed.

In the present invention, the thickness of the "sheet" is not particularly limited, and even if "sheet" is replaced with "film" within the range of commonly used terms, Are the same, the term "sheet" in the specification of the present invention also encompasses "film".

[0008]

Next, the present invention will be described in detail. In the present invention, the resin mainly constituting the transparent resin base used for the light forward scattering function layer is not particularly limited as long as it is a transparent resin capable of dispersing organic fine particles and / or inorganic fine particles. Resins used for the functional layer can be used. Preferably, it is an optically transparent thermoplastic resin.

As such a transparent resin, a synthetic resin,
Alternatively, various types of natural synthetic resins can be used.
Examples of the synthetic resin include linear polyester, acrylic resin, melamine resin, silicon resin, urethane resin, epoxy resin, styrene resin, vinyl acetate resin and the like. Examples of natural synthetic resins include, for example, cellulose ester resins such as ethyl cellulose and hydroxypropyl cellulose, cellulose acetate, cellulose propionate, cellulose butyrate, cellulose acetate propionate, and cellulose ester resins such as cellulose acetate butyrate. Cellulose derivative resins are exemplified. These may be used alone or in combination of two or more.

[0010] The light scattering sheet of the present invention comprises
When the light scattering layer is laminated on the transparent substrate sheet,
It is preferable that the transparent base sheet is made of a material having the same optical characteristics as the transparent base sheet. In particular, when the transparent base sheet also serves as a protective layer for the polarizing layer, as described later, even if the resin mainly constitutes the transparent resin base used for the light-scattering function layer, the protective layer for the polarizing layer is generally generally formed. It is preferable to use the same material as the material. As the protective layer of the polarizing layer, generally, since a cellulose ester resin is generally used, the resin mainly constituting the transparent resin base is preferably a cellulose derivative resin, especially a cellulose ester resin, especially a cellulose acetate resin. Good, more preferably, triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, and particularly preferably, triacetyl cellulose having high optical isotropy and high transparency.

As the above-mentioned cellulose acetate resin, a resin produced from cotton linter or wood pulp by a known method such as a methyclo method or a fibrous acetylation method can be used.

A preferred cellulose acetate resin has an average acetylation degree (acetylation degree) of 58.0.
~ 62.5% is good. However, the degree of acetylation means the amount of bound acetic acid per unit weight of cellulose, and the degree of acetylation is used for measuring and calculating the degree of acetylation in ASTM: D-817-91 (test method for cellulose acetate and the like). Perform in compliance.

The transparent resin base used for the light forward scattering function layer may contain other components such as a plasticizer as long as the function of the present invention is not impaired.

In the present invention, the material constituting the organic fine particles and / or the inorganic fine particles (hereinafter, sometimes abbreviated as “fine particles”) used in the light forward scattering function layer is transparent or light scattering. The material is not particularly limited as long as it is translucent fine particles, and can be appropriately selected according to the desired properties of the light forward scattering functional layer.

Materials constituting the organic fine particles include, for example, polyolefins such as polyethylene and polypropylene; nylons such as nylon 6, nylon 12, and copolymers of nylon 6 and nylon 12, such as nylon, cellulose, polyester, polystyrene, and poly (meth). A homopolymer such as an acrylic resin such as acrylic acid, or a thermoplastic resin such as a copolymer of two or more monomers composing these homopolymers, or another monomer copolymerizable with the monomer, or a melamine resin. Thermoplastic resins are exemplified.

Materials constituting the inorganic fine particles include, for example, alkali-free glass, boron nitride, mica (mica),
A composite material of mica and boron nitride is exemplified.

The material constituting the fine particles may contain other components as long as the action of the present invention is not impaired.

The shape of the organic fine particles and / or the inorganic fine particles is not particularly limited.
Spherical, spherical (including potato-like irregular shapes), spherical with protrusions on the surface of spinach, spheroid, thin plate, needle, disk, rugby ball, filament (rod), etc. Can be

The size of the organic fine particles and / or the inorganic fine particles is not particularly limited, and can be appropriately selected according to the desired physical properties and thickness of the light forward scattering function layer.
When the shape of the fine particles is truly spherical, preferably the average particle diameter is 1 to 100 μm, more preferably 1 to 20 μm,
Particularly preferably, the thickness is 2 to 15 μm. When the fine particles have a shape other than a true spherical shape, the maximum length is preferably 1 to 100 μm, more preferably 1 to 20 μm, and particularly preferably 2 to 15 μm.

The fine particles may be used alone or in combination of two or more.

In the present invention, the main function of the light forward scattering functional layer is to have as little backscattering as possible and to scatter light forward only. To reduce blur and improve visibility, the total light transmittance is large,
The haze is preferably in a specific range.

Haze of light forward scattering function layer (JIS K7
150), preferably 10 to 50%,
More preferably, it is in the range of 15 to 25%.
If the haze exceeds 50%, when incorporated into a reflective liquid crystal display device, the light transmittance is low and the luminance is not improved, and at the same time, the image is blurred and the visibility is reduced. Haze is 1
If it is less than 0%, when incorporated into a reflective liquid crystal display device, the illumination and the user are reflected on the mirror reflection layer of the display device, and the display quality deteriorates.

The total light transmittance (JIS) of the light forward scattering functional layer
100% as much as possible)
However, due to the refractive index of the constituent materials, especially the transparent resin base, even if a material having no absorption in the visible light region is used, some specular reflection occurs. Is preferably 90% or more. When triacetyl cellulose is used as a constituent material of the transparent resin base, the refractive index is 1.487, and the reflectance when perpendicular light is made incident on a sheet made of triacetyl cellulose with the refractive index of air being 1 Is 3.8 in theory
% And the transmittance is 96.2%, so that the total light transmittance is 9
It is preferred to be about 5 to 96.

In the present invention, the mixing ratio of the transparent resin base to the organic fine particles and / or the inorganic fine particles is not particularly limited, and can be appropriately set according to the desired properties of the light forward scattering functional layer.

In the present invention, the thickness of the light forward scattering function layer is not particularly limited, and can be appropriately set according to desired physical properties, the particle diameter of the fine particles used, the maximum length, and the like. In particular, as described below, when the light forward scattering function layer is laminated on a transparent substrate sheet, and when the substrate sheet also serves as a protective layer for the polarizing layer, the thickness of these transparent substrate sheets and other layers The setting is made in consideration of the cost and the cost. When the transparent substrate sheet also serves as the protective layer of the polarizing layer,
Since the protective layer of the polarizing layer is usually about 80 μm, the thickness of the light forward scattering function layer is preferably 1 to 80 μm, and more preferably 5 to 30 μm.

The light scattering sheet of the present invention may be constituted by a light forward scattering function layer alone, or may have a laminated structure in which the light forward scattering function layer is laminated on at least one surface of a transparent substrate sheet. .

The transparent substrate sheet is not particularly limited as long as it satisfies the properties required as a substrate such as optical isotropy, transparency, heat resistance, curl resistance and solvent resistance. Examples thereof include various resins such as a polyester resin, an amorphous polyester resin, an acrylic resin, a vinyl resin, a polycarbonate resin, and polyether sulfone. These may be used alone or in combination of two or more.

As described later, when the transparent substrate sheet also serves as a protective layer for the polarizing layer, it is generally preferable to use the same material as that for forming the protective layer for the polarizing layer. As with the transparent resin base constituting the scattering function layer, preferably a cellulose derivative resin, especially a cellulose ester resin, especially a cellulose acetate resin, more preferably triacetyl cellulose, diacetyl cellulose, cellulose acetate propionate, particularly Preferably, it is optically isotropic and highly transparent triacetyl cellulose. As a preferable cellulose acetate-based resin, one having an average degree of acetylation (degree of acetylation) of 58.0 to 62.5% is preferable, similarly to the transparent resin base constituting the light forward scattering function layer.

It is particularly preferable that the materials constituting the transparent resin base and the transparent base material sheet constituting the light forward scattering functional layer are of the same kind, from the viewpoint of lamination suitability. It is preferably acetylcellulose.

The materials constituting the transparent substrate sheet include:
Other components such as a plasticizer may be contained as long as the action of the present invention is not impaired.

The method for forming the transparent substrate sheet is not particularly limited, and a commonly used forming method can be used. When the transparent substrate sheet is formed from a cellulose acetate resin, it is preferably formed by a solvent casting method or a melt casting method. In the solvent casting method, a solution (dope) in which a cellulose acetate resin is dissolved in a solvent is cast on a support, the solvent is dried and removed, and the sheet is formed by peeling off the support from the support. In the melt casting method, a material obtained by melting a cellulose acetate resin by heating is cast on a support, solidified by cooling, and then separated from the support to form a sheet. The solvent casting method is preferable in practical use because a film having higher flatness can be produced than the melt casting method.

Although the thickness of the transparent substrate sheet is not particularly limited, as described later, a polarizing layer is provided on at least a surface of the transparent substrate sheet opposite to the polarizing layer side, and a light forward scattering function layer is provided on the polarizing substrate. In the case where the transparent base sheet in the light scattering sheet of the present invention is formed so as to serve as the protective layer of the polarizing layer, the thickness is preferably set to 1 to 80 μm, and furthermore, the correlation with the thickness of the light forward scattering functional layer. Is preferably set to 50 to 70 μm.

In the light scattering sheet of the present invention, the method for forming the light forward scattering functional layer is not particularly limited, and can be appropriately selected according to the structure of the light scattering sheet. The light scattering sheet of the present invention is composed of the light forward scattering function layer alone, or has a laminated structure in which the light forward scattering function layer is laminated on at least one surface of the transparent substrate sheet. In the case of, according to the properties of the constituent material of the light forward scattering functional layer, particularly the material constituting the transparent resin base, the light forward scattering functional layer is formed into a sheet using a generally used sheet forming method. And a light scattering sheet.

In the case where the light forward scattering function layer has a laminated structure laminated on at least one surface of the transparent substrate sheet,
The light forward scattering function layer may be separately formed into a sheet in the same manner as when formed alone, and laminated with a transparent substrate sheet by bonding or the like, or directly laminated on the transparent substrate sheet as described below. You may. As a method of directly laminating the light forward scattering functional layer on the transparent base material sheet, for example, when a cellulose acetate resin is used as a material constituting the transparent resin base, the cellulose acetate resin is mixed with methylene chloride or the like in a desired number of parts by weight. And then dispersing fine particles in the solution and dispersing the mixed dispersion on the surface of the transparent substrate sheet by coating or the like, followed by drying and removing the solvent.

The solvent is preferably methylene chloride, and may be used as a mixed solvent with methylene chloride by adding methanol as needed.

When a cellulose acetate resin is used as a material constituting the transparent resin base and the light forward scattering function layer is directly laminated on the transparent substrate sheet, the mixing ratio of the cellulose acetate resin and the solvent at the time of production is as follows. The mixing ratio is not particularly limited, and the mixing ratio may be appropriately set depending on the coating method, workability, type of solvent, and the like.
000 parts by weight, more preferably 10 parts by weight.
It is preferably from 00 to 2000 parts by weight.

In any of the methods for forming the light forward scattering function layer, the method of mixing the transparent resin base with the organic fine particles and / or the inorganic fine particles and, if necessary, the solvent used is not particularly limited. Instead, they can be mixed simultaneously or sequentially and mixed and dispersed using a commonly used stirrer or the like.

When the light forward scattering functional layer is directly laminated on the transparent substrate sheet, the method of applying the mixed dispersion solution to the surface of the transparent substrate sheet as described above includes a reverse roll coating method, a die coating method, and a comma coater method. , A spray coating method, a gravure coating method, a kiss reverse coater method, a dipping method, a knife coating method, a spin coating method, a laminating method, a bar coating method and the like, but are not particularly limited, and are not particularly limited. It is appropriately selected depending on the mixing ratio of the fine particles, the viscosity of the mixed dispersion solution, the desired thickness of the light forward scattering functional layer, the surface condition of the transparent substrate sheet, and the like.

The method of drying and removing the solvent in the mixed and dispersed solution spread on the surface of the transparent substrate sheet is not particularly limited, and various methods such as natural drying, hot air drying, and vacuum drying can be used. Can be

The thickness of the light-scattering sheet of the present invention is not particularly limited. However, when the light-scattering sheet also serves as the protective layer of the polarizing layer as described later, the protective layer of the polarizing layer is usually about 80 μm. As the total thickness of the forward scattering function layer,
It is set appropriately.

Further, in the present invention, the ratio of the thickness of the light forward scattering functional layer to the thickness of the transparent substrate sheet is not particularly limited.
It is appropriately set according to the desired properties of the light scattering sheet.

The light-scattering sheet of the present invention comprises a liquid crystal display,
Particularly, formation of a light forward scattering function layer in a reflection type liquid crystal display device having a single polarizing layer such as a single polarizing plate type reflection type liquid crystal display device and having a light forward scattering function layer on the outermost layer closer to the polarizing layer It can be suitably used for applications. Further, the above-mentioned reflection type liquid crystal display device changes the liquid crystal layer to HAN (Hybrid).
(Aligned Nematic) Oriented RO
CB (Reflective Optically C
In particular, it can be suitably used in the case of an (Ompensed Bend) type liquid crystal display device.

In a reflection type liquid crystal display device having one polarizing layer as described above, a polarizing plate having a protective layer provided on both sides of a polarizing layer (polarizer) is usually used as a polarizing layer. As the layer, the transparent substrate sheet in the light scattering sheet of the present invention can also be used. That is, by forming a polarizing layer (a polarizing layer in a polarizing plate) on the light scattering sheet of the present invention such that the light forward scattering functional layer is provided on at least the surface of the transparent substrate sheet opposite to the polarizing layer side. The number of members in the liquid crystal display device can be reduced, which is advantageous in terms of cost and quality. Usually, the protective layer uses a large amount of cellulose acetate resin, in which case,
By forming the transparent substrate sheet from a cellulose acetate-based resin, even if the transparent substrate sheet and the protective layer of the polarizing layer are also used, there is no complicated refraction or loss at the interface, and light can be transmitted effectively. As compared with the case where the polarizing layer and the light forward scattering function layer are formed as separate members and arranged like a combination of a polarizing plate and a light scattering sheet, the liquid crystal layer and the light forward scattering function layer The distance can be shortened, blurring of an image is less likely to occur, and visibility can be improved.

FIGS. 1 and 2 show an example of an embodiment in which the light scattering sheet of the present invention is used as a forward scattering layer of a reflection type liquid crystal display device. FIG. 1 shows a configuration of a reflection type liquid crystal display device using the light scattering sheet of the present invention as a light forward scattering function layer, and FIG. 2 shows a configuration of a light scattering sheet used in the liquid crystal display device of FIG. The reflection type liquid crystal display device 1 includes a light scattering sheet 2 (2a is a light forward scattering functional layer, 2b is a transparent base sheet also serving as a protective layer of a polarizing layer, 2c is a polarizing layer, and 2d is the other of the polarizing layer of the present invention). A birefringent layer 3, a reflective liquid crystal cell 4, a specular reflection layer 5, and a back glass 6. In the light scattering sheet 2 of the present invention, as shown in FIG. 2, a light forward scattering functional layer 2a composed of a transparent resin base 7a and fine particles 7b is formed on one surface of a transparent base sheet 2b, and the other surface. And a protective layer 2d made of a cellulose acetate resin in the direction inward of the display device. In the light forward scattering function layer 2a, organic fine particles and / or inorganic fine particles 7b are dispersed in a transparent resin base 7a made of cellulose acetate resin or the like, and light passing through the light forward scattering function layer 2a is directed forward. It scatters and exhibits a forward scattering effect. Further, by adjusting the total light transmittance and haze of the light forward scattering function layer 2a, the forward scattering intensity can be increased, the back scattering intensity can be reduced, and the visibility can be improved by reducing the occurrence of image blur. It is possible to improve the image in a well-balanced manner and obtain a bright image having a good contrast. In addition, since the transparent substrate sheet of the light scattering sheet also functions as the protective layer of the polarizing layer, the occurrence of image blur can be further prevented.

The light-scattering sheet of the present invention is used not only as a light-scattering functional layer of a reflective liquid crystal display device as described above, but also for controlling the light of various devices such as lighting equipment and illuminated signboards. It is also possible to use.

Hereinafter, the present invention will be described in more detail with reference to Test Examples and Examples. Test example Test method (1) Total light transmittance measurement For the light scattering sheets of Examples 1 to 8 and Reference Examples 1 to 4,
The total light transmittance was measured using a haze meter (NDH-300A, manufactured by Nippon Denshoku Industries Co., Ltd.) according to JIS K7105.

(2) Measurement of Diffuse Light Transmittance The light scattering sheets of Examples 1 to 8 and Reference Examples 1 to 4
The diffused light transmittance was measured in the same manner as in the test (1).

(3) Parallel Line Transmittance The light scattering sheets of Examples 1 to 8 and Reference Examples 1 to 4
Similar to the test (1), the parallel line transmittance was measured.

(4) Haze Measurement The light scattering sheets of Examples 1 to 8 and Reference Examples 1 to 4
Haze was measured in the same manner as in Test (1).

(5) Evaluation of Display Visibility The light scattering sheets of Examples 1 to 8 and Reference Examples 1 to 4
A reflective liquid crystal display device having a simple configuration as shown in FIG. 3 was prepared, and the display visibility was evaluated. (The light forward scattering function and the display visibility are mainly due to the characteristics of the light forward scattering function layer. It was not necessary to evaluate with a light scattering sheet having a material sheet, and the light scattering sheet with only the light forward scattering functional layer was evaluated.) In FIG. 3, 2a is a light forward scattering function layer, 5 is a specular reflection layer, 6 is a back glass, and an OHP sheet on which characters are printed as images with transparent glass (8) instead of a birefringent layer and a reflective liquid crystal cell. (9) was placed so that the OHP sheet was on the back side, and visibility such as blurring of an image was evaluated.

2. Test Results Table 1 shows the results of the above tests (1) to (5).

[0052]

[Table 1]

From the results shown in Table 1, the light scattering sheets (light forward scattering functional layers) of Examples 1 to 8 have a total light transmittance of 90% or more and a haze of 10 to 50%. It can be seen that the display visibility is good. In addition, the light scattering sheets (light forward scattering functional layers) of Examples 1, 3, 5, and 8 have a haze in the range of 15 to 25%, and display visibility is very good. In addition, from Example 1 and Example 8, it can be seen that similar effects can be obtained depending on the configuration even if the transparent resin base is made of a different material. On the other hand, the light scattering sheets (light forward scattering functional layers) of Reference Examples 1 to 3 have a total light transmittance of 90%.
%, But haze exceeds 50%, display visibility is poor, and the light scattering sheet (light forward scattering functional layer) of Reference Example 4
Has a low total light transmittance and a haze of more than 50%,
It can be seen that the display visibility is poor. The light scattering sheet (light forward scattering functional layer) of Reference Example 4 had a dark display screen and impaired display quality.

[0054]

EXAMPLES Light scattering sheets of Examples and Reference Examples were prepared using the following materials. [Light forward scattering functional layer]-Thermoplastic resin used for transparent resin base Cellulose triacetate resin (TAC) (LT-55, manufactured by Daicel Chemical Industries, specific gravity 1: 3, average acetylation degree 61%) Cellulose diacetate resin ( DAC) (LT-40, manufactured by Daicel Chemical Industries, specific gravity 1: 3, average acetylation degree 55%)-Organic fine particles Polymethyl methacrylate spherical particles (Techpolymer MBX-8; Sekisui Plastics Co., Ltd.)
Spherical, average particle diameter: 6.8 μm, true specific gravity 1.2) Polymethyl methacrylate spherical particles (Techpolymer MB20X-5; manufactured by Sekisui Plastics Co., Ltd., true spherical, average particle diameter: 5.3 μm , True specific gravity 1.
2) Spherical particles of polymethyl methacrylate (Techpolymer MBX-2AB, manufactured by Sekisui Plastics Co., Ltd., spherical, average particle diameter 2.5 μm, true specific gravity 1.
2) Nylon 6-nylon 12 copolymer irregular shaped particles (Nylon 6/12 porous fine particles Lot No. 130
-2, made by Sekisui Plastics Co., Ltd., potato-shaped variant,
Average particle diameter 10.4 μm, true specific gravity 1.03) Acrylic resin flat particles (IP-01; flat, maximum particle length 11 μm, true specific gravity 1.2, manufactured by Hamakawa Paper Co., Ltd.) Inorganic fine particles Mica (mascobite; Sekisui Plastics Co., Ltd., disk-shaped,
Maximum particle length 10-15 μm, thickness 0.5-0.9 μ
m, specific gravity 2.7) Filamentous particles (micro rod PF-30S; manufactured by NEC Corporation, rod shape (filament shape), specific gravity 2.57 Average rod diameter 2.99 μm, average rod length 16. 7μ
m) sheet glass (microglass glass flake REF015;
Nippon Sheet Glass Fiber Co., Ltd., scaly, maximum diameter 15 μm, thickness 5 μm, specific gravity 2. , 5) ・ Plasticizer TPP ・ Solvent Mixed solvent (methylene chloride / methanol = 9/1) Acetone

[Transparent substrate sheet] Cellulose triacetate resin (LT-55, manufactured by Daicel Chemical Industries, Ltd., specific gravity 1:
3. Average acetylation degree 61%) ・ Solvent Mixed solvent (methylene chloride / methanol = 9/1)

Examples 1 to 8 and Reference Examples 1 to 4 The above-mentioned materials were used as the thermoplastic resin, organic or inorganic fine particles, plasticizer and solvent used for the transparent resin base.
After blending according to the blending of Table 2 below, and dissolving and dispersing and mixing using a three-one motor, the obtained solution (dope) was cast on a support made of non-alkali glass by a bar coating method, and heated at 40 ° C. The solvent was dried and removed at 100 ° C. for 3 minutes and peeled off the support, and the thickness was 30 μm.
A light-scattering sheet comprising the light-forward scattering functional layer was obtained as Examples and Reference Examples.

Examples 9 to 16

The solution (dope) used in Examples 1 to 8 was cast on a transparent substrate sheet by a bar coating method,
The solvent was dried and removed at 100 ° C. for 3 minutes, and a light-scattering sheet having a light-scattering layer having a thickness of 30 μm was obtained.

[Production of Transparent Substrate Sheet] Cellulose triacetate resin was blended and dissolved in a solvent at a weight ratio of 1: 9, and the resulting solution (dope) was subjected to a solvent casting method to prepare a support (non-coated). After casting and drying the solvent at 40 ° C. for 3 minutes and at 100 ° C. for 1 minute, it was peeled off from the support to obtain a sheet having a thickness of 60 μm.

[0060]

[Table 2]

[0061]

As described above, the light scattering sheet of the present invention scatters light passing through the light forward scattering functional layer to the front, and has a forward scattering effect, while having the total light transmittance of the light forward scattering functional layer. By adjusting the haze, the forward scatter intensity is increased, the back scatter intensity is reduced, the visibility is improved by preventing the occurrence of image blur, and a well-balanced image is obtained. Obtainable. In addition, since the transparent base sheet of the light scattering sheet also serves as a protective layer of the polarizing layer, it is possible to further prevent the occurrence of image blur, and to make the reflective liquid crystal display device, particularly the liquid crystal layer HAN-oriented. When used for forming a light forward scattering function layer of an R-OCB type liquid crystal display device, a very high quality image can be obtained in which the display is bright and image blurring is prevented.

[Brief description of the drawings]

FIG. 1 is a diagram showing a configuration of a reflection type liquid crystal display device using a light scattering sheet of the present invention as a light forward scattering function layer.

FIG. 2 is a diagram illustrating a configuration of a light scattering sheet used in the liquid crystal display device of FIG.

FIG. 3 is a diagram showing a configuration of a reflective liquid crystal display device having a simple configuration for evaluating display visibility.

[Explanation of symbols]

 Reference Signs List 1 reflective liquid crystal display device 2 light scattering sheet 2a light forward scattering functional layer 2b transparent base sheet 2c polarizing layer 2d protective layer 3 birefringent layer 4 reflective liquid crystal cell 4 'hybrid-aligned liquid crystal 5 specular reflection layer 6 Back glass 7a Transparent resin base 7b Fine particles 8 Transparent glass 9 OHP sheet with characters printed

 ──────────────────────────────────────────────────続 き Continued on the front page F-term (Reference) 2H042 BA02 BA12 BA15 BA20 2H049 BB33 BB49 BB62 BB63 2H091 FA08X FA08Z FA11X FA14Z FA31X FA31Z FB02 FB12 FB13 FD06 GA06 GA16 HA09 LA16 4F100 AA01B01 AS06 A06A01B01 DE04B GB41 JB16A JN00B JN01A JN30B YY00B

Claims (14)

[Claims] 1. A light-scattering sheet comprising a transparent resin base and a light-forward scattering functional layer in which organic fine particles and / or inorganic fine particles are dispersed. 2. A reflection type liquid crystal display device having a single polarizing layer and a light scattering function layer on the outermost layer closer to the polarizing layer for forming a light scattering function layer. 2. The light scattering sheet according to 1. 3. The light-scattering sheet according to claim 2, wherein the light-scattering sheet is for forming a light forward scattering function layer of an R-OCB type liquid crystal display device in which the liquid crystal layer is HAN-oriented. 4. The method according to claim 1, wherein the transparent resin base is mainly made of an optically transparent thermoplastic resin.
The light-scattering sheet according to any one of claims 1 to 3. 5. The light-scattering sheet according to claim 4, wherein the thermoplastic resin is a cellulose derivative resin. 6. The light-scattering sheet according to claim 4, wherein the thermoplastic resin is a cellulose ester resin. 7. The light-scattering sheet according to claim 4, wherein the thermoplastic resin is a cellulose acetate resin. 8. The light-scattering sheet according to claim 1, wherein the organic fine particles and / or the inorganic fine particles have a true spherical shape with an average particle diameter of 1 to 100 μm. 9. The light-scattering sheet according to claim 1, wherein the organic fine particles and / or the inorganic fine particles are particles having a maximum length of 1 to 100 μm. 10. Haze of light forward scattering functional layer (JIS
The light-scattering sheet according to any one of claims 1 to 9, wherein (measured in accordance with K7150) is 10 to 50%. 11. The light-scattering sheet according to claim 1, wherein a light-forward scattering function layer is laminated on at least one surface of the transparent substrate sheet. 12. The transparent base sheet mainly comprising a cellulose acetate resin.
The light-scattering sheet according to any one of the above. 13. The light-scattering sheet according to claim 11, wherein the transparent base sheet mainly comprises triacetyl cellulose. 14. The polarizing layer is formed so that a light forward scattering functional layer is formed on at least the surface of the transparent substrate sheet opposite to the polarizing layer side. The light scattering sheet according to claim 1.