JP2003307625A - Polarizer, polarizing plate, liquid crystal display device, image display device and method for manufacturing polarizer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a polarizer which can be used for an image display device such as a liquid crystal display device, a plasma display device and electroluminescence display device and with which coloring of transmitted light is suppressed. <P>SOLUTION: Problem can be solved by the polarizer containing a polymer film in which the difference between the maximum value and the minimum value of a first main transmittance in the 400 to 700 nm wavelength range is ≤10%. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a polarizer, a polarizing plate,
The present invention relates to a liquid crystal display device, an image display device, and a method for manufacturing a polarizer.

[0002]

2. Description of the Related Art Since a liquid crystal display device (hereinafter abbreviated as "LCD") is a non-self-luminous display device, the liquid crystal panel must be illuminated in order to display its screen. Generally, a backlight, a front light, or the like arranged on the front surface or the rear surface of a liquid crystal panel of a liquid crystal display device is used as illumination (for example, refer to Patent Document 1).
However, since these backlights and front lights have a thickness of about 2 mm or more, there is a problem in that the thickness of the entire liquid crystal display device increases significantly.

To solve this problem, there is known a liquid crystal display device having a side light arranged on one side surface of a liquid crystal panel instead of a backlight and a light control layer arranged on one surface of the liquid crystal panel. There is. The light emitted from the sidelight is transmitted inside the liquid crystal display device, and the light control layer reflects the emitted light to transmit the emitted light over the entire liquid crystal display device and illuminate the front surface of the liquid crystal panel. (For example, refer to Patent Document 2). This light control layer is thinner than the thickness of the backlight or the front light, for example, 200 μm or less. Therefore, the thickness of the liquid crystal display device having the sidelight and the light control layer can be made significantly smaller than the thickness of the liquid crystal display device having the backlight or the like.

However, the liquid crystal display device having the sidelight and the light control layer has a problem that the emitted light is colored as the light is transmitted to the side opposite to the sidelight.

[0005]

[Patent Document 1] Japanese Patent Laid-Open No. 11-250715

[Patent Document 2] Japanese Patent Laid-Open No. 2001-318379

[0006]

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a polarizer which can be used in an image display device such as a liquid crystal display device and which suppresses coloring of transmitted light. And

[0007]

Means for Solving the Problems The inventors of the present invention have conducted extensive studies to solve the above-mentioned problems, and as a result, have found that the polarizer has a thickness of 400 nm.
Focusing on the first main transmittance at a wavelength of up to 700 nm, and by using a polarizer having a difference between the maximum value and the minimum value within 10%, it is possible to suppress coloring of light after passing through the polarizer. The present invention has been completed and the present invention has been completed.

Therefore, the present invention is 400 nm to 70 nm.
It is intended to provide a polarizer in which the difference between the maximum value and the minimum value of the first main transmittance at a wavelength of 0 nm is within 10%.

The first main transmittance is the transmittance when the vibration direction of the incident linearly polarized light and the transmission axis of the polarizer coincide with each other. The first main transmittance (k ₁ ) is expressed by the following Expression 1 using the values of parallel transmittance and orthogonal transmittance. (Equation _{1) k 1 = 0.5 × √2} {[(H 0 + H 90) 1/2 + (H 0 -H 90) 1/2]} However, H _0: parallel transmittance, H _90: orthogonal Transmittance

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The polarizer of the present invention has a thickness of 400 nm to
The difference between the maximum value and the minimum value of the first main transmittance at a wavelength of 700 nm is within 10%, preferably within 7%, more preferably within 5%. In addition, the polarizing plate of the present invention is 400
The minimum value of the first main transmittance at a wavelength of nm to 700 nm is, for example, 70% or more, preferably 80% or more, and more preferably 85% or more. Wavelength shorter than 400 nm,
At wavelengths longer than 700 nm, there is almost no emission from the lamp that serves as the light source, and the visual sensitivity is low.
Optical characteristics in the wavelength region of up to 700 nm are important in liquid crystal display devices.

In the above polarizer, the visibility correction (JIS
Z 8701) has a single transmittance of, for example, 45% or more. By using the polarizer having such characteristics, the display of the image display device can be made brighter and the display quality can be improved.
In the above-mentioned polarizer, the luminosity corrected single transmittance is 4
It is preferably at least 5.5%, more preferably at least 46%.
Further, the polarization degree of the polarizer is preferably 95% or more.

In the polarizer, the parallel b value is, for example, -2 to 0.5. The white display of the image display device can be whitened by using the polarizer having such characteristics. In the polarizer, the parallel b value is preferably -1.5 to 0.2, more preferably -1 to 0. The parallel b value is defined by the Hunter-Lab system. Specifically, for example, according to JIS K 7105 5.3, the tristimulus values (X, Y, Z) of the sample are measured using a spectrophotometer or a photoelectric colorimeter, and these values are measured for color difference in the Lab space. The parallel b value can be calculated by substituting it into the Hunter's formula shown below as a formula. Auxiliary Illuminant C (JIS Z 8720) is usually used for this measurement.
Parallel b value = 7.0 (Y−0.847Z) / Y ^1/2 [wherein, Y and Z are tristimulus values of the XYZ color system corrected for visibility in the auxiliary illuminant C, 2 ° visual field. ]

The polarizer of the present invention is a hydrophilic polymer such as a polymer film such as a polyvinyl alcohol (PVA) film, a partially formalized PVA film, an ethylene / vinyl acetate copolymer partially saponified film or a cellulose film. It is manufactured from film. The polarizer of the present invention is preferably produced from a polyvinyl alcohol film as a raw material.

The polarizer of the present invention is particularly preferably used for a black and white reflective LCD. The use of the polarizer of the present invention enables bright white display when white is displayed.

An example of the method for producing the polarizer of the present invention will be shown below. The polarizer can be produced by subjecting the polymer film to a swelling treatment, a dyeing treatment, a crosslinking treatment, a stretching treatment such as uniaxial stretching, and then drying this. The dyeing, crosslinking, and stretching treatments may be performed separately or simultaneously, and the order of the treatments can be arbitrarily determined. This will be specifically described below. The polarizer of the present invention only needs to satisfy the above condition that the difference between the maximum value and the minimum value of the first main transmittance at a wavelength of 400 nm to 700 nm is within 10%. Not limited.

(1) Swelling treatment The polymer film is immersed in a swelling bath to swell,
Stretching treatment is performed in the swelling bath. The thickness of the polymer film is preferably 20 to 200 μm, more preferably 30 to 150 μm, and particularly preferably 40 to 100 μm.

As the solution for the swelling bath, for example, water,
An aqueous glycerin solution or the like can be used, and among these, water is preferable. The temperature of this swelling bath is, for example, 10 to 50 ° C.
It is preferably in the range of, more preferably 20 to 4
The temperature is 5 ° C, particularly preferably 30 to 40 ° C. Immersion time in the swelling bath is not particularly limited, for example,
It is preferably in the range of 20 to 240 seconds, more preferably 30 to 180 seconds, and particularly preferably 40 to 1 seconds.
50 seconds. The following dyeing treatment can be performed without performing this swelling treatment.

(2) Dyeing treatment The polymer film is pulled out from the swelling bath, immersed in a dyeing bath containing, for example, a dichroic dye, and further uniaxially stretched in the dyeing bath. That is, the dichroic dye is adsorbed on the polymer film by the dipping, and the dichroic dye is oriented in one direction by stretching.

As the dichroic dye, a conventionally known substance can be used, and examples thereof include iodine and organic dyes. Examples of the organic dye include red BR, red LR, red R, pink LB, rubin BL, bordeaux GS, sky blue LG, lemon yellow, blue BR,
Blue 2R, Navy RY, Green LG, Violet LB, Violet B, Black H, Black B, Black GSP, Yellow 3G, Yellow R, Orange LR,
Orange 3R, Scarlet GL, Scarlet KG
L, Congo Red, Brilliant Violet BK,
Supra Blue G, Supra Blue GL, Direct Sky Blue, Direct First Orange S, First Black, and Supra Orange GL can be used. Among these dichroic dyes, for example, iodine is preferably used because of its high transmittance and high polarization degree.

These dichroic dyes may be used alone or in combination of two or more. When using the organic dye, it is preferable to combine two or more kinds from the viewpoint of, for example, neutralizing the visible light region. Specifically, for example, a combination of Congo Red and Supura Blue G, a combination of Supura Orange GL and Direct Sky Blue, a combination of Direct Sky Blue and First Black, and the like can be mentioned.

As the solution for the dyeing bath, a solution prepared by dissolving the dichroic dye in a solvent can be used. As the solvent, for example, water can be used, but an organic solvent compatible with water may be further added. The concentration of the dichroic dye in the solution is not particularly limited, but is, for example, 0.0
The amount is preferably in the range of 1 to 1% by weight, more preferably 0.03 to 0.8% by weight, and particularly preferably 0.05 to 0.6% by weight.

The immersion time of the polymer film in the dyeing bath is not particularly limited, but is preferably in the range of 5 seconds to 10 minutes, more preferably 10 seconds to 5 minutes, and particularly preferably 20. Seconds to 3 minutes. The temperature of the dyeing bath is preferably in the range of 10 to 50 ° C, more preferably 15 to 45 ° C,
It is particularly preferably 20 to 40 ° C.

When pulling out the polymer film from the bath, in order to prevent the occurrence of dripping, for example, a conventionally known liquid-running roll may be used, or the film may be applied to a plate and then aired. The liquid may be scraped off with a knife. The same applies to the following processing.

Such a dyeing treatment may be, for example, a method of stretching while applying or spraying an aqueous solution containing a dichroic dye to the polymer film, in addition to the method of dipping in the dyeing bath as described above. Good. The stretching method is
There is no particular limitation, and for example, the tension applied to the polymer film can be appropriately adjusted and stretched.

(3) Crosslinking Treatment The polymer film is taken out of the dyeing bath, immersed in a crosslinking bath containing a crosslinking agent, and further stretched in the crosslinking bath. By carrying out the crosslinking treatment, running stability is maintained.

As the cross-linking agent, conventionally known substances can be used, and examples thereof include boric acid, borax, glyoxal, and boron compounds such as glutaraldehyde. These may be used alone or in combination of two or more. As the solution for the crosslinking bath, a solution prepared by dissolving the crosslinking agent in a solvent can be used. As the solvent, for example,
Although water can be used, it may further contain an organic solvent compatible with water.

The concentration of the cross-linking agent in the solution is not particularly limited, but is preferably in the range of, for example, 0.5 to 10% by weight, more preferably 2 to 8% by weight, and particularly preferably 3 to. 6% by weight.

In addition to the boric acid compound, the cross-linking agent-containing solution provides uniform properties in the plane of the polarizer,
For example, potassium iodide, lithium iodide, sodium iodide, zinc iodide, aluminum iodide, lead iodide,
An auxiliary agent such as iodide such as copper iodide, barium iodide, calcium iodide, tin iodide and titanium iodide may be contained. The content of the auxiliary in the solution, for example,
It is 0 to 1.5% by weight, preferably 0 to 1.0% by weight, and more preferably 0 to 0.7% by weight.

The temperature of the crosslinking bath is usually 20 to 50 ° C.
And the immersion time of the polymer film is not particularly limited, but is usually 10 seconds to 2 minutes, preferably 20 seconds to 1 minute.

The stretching in this crosslinking treatment can be carried out, for example, while immersing the polymer film in the crosslinking bath, as described above. Further, as in the case of the dyeing treatment, for example, a method of applying the cross-linking agent-containing solution to the relaxed polymer film while applying or spraying the solution may be used. Further, the stretching method is not particularly limited, for example,
Examples of the method include a method of appropriately adjusting the tension applied to the film and a method of stretching with a fixed stretching ratio. These methods may be performed plural times or in combination. The tension can be appropriately adjusted depending on, for example, the type of crosslinking agent, the temperature of the crosslinking bath, the concentration of the crosslinking agent, the type of polymer film, the average degree of polymerization, and the like.

(4) Stretching Treatment The polymer film is pulled out from the crosslinking bath, immersed in the stretching bath, and further stretched in this stretching bath. The solution for the stretching bath is not particularly limited, but, for example, a solution containing boric acid, various metal salts, other iodide compounds, zinc compounds and the like can be used. As a solvent for this solution, for example, water, ethanol or the like can be used.

The temperature of the stretching bath is, for example, 30 to 75.
It is preferably in the range of ℃, more preferably 40 ~
It is 70 ° C., and particularly preferably 50 to 65 ° C.

(5) Washing with water The polymer film is pulled out from the stretching bath, washed with water, and dried. Thereby, a polarizer can be manufactured. The number of times of water washing is not particularly limited, but is preferably 1 to 4 times, more preferably 1 to 3 times, and particularly preferably 1 to 2 times.

The drying is not particularly limited, for example, natural drying, air drying, heat drying, etc., but in the case of heat drying, the temperature is 1
The range of 0 to 50 ° C. is preferable, and 20 to 4 is more preferable.
The temperature is 5 ° C, particularly preferably 30 to 40 ° C. Among these respective treatments, for example, the dyeing, stretching and crosslinking treatments may be performed separately, but may be performed simultaneously. Moreover, you may add water washing for every process.

The thickness of the polarizer of the present invention is, for example, 5 to 80 μm.
m, but is not limited to this. The thickness of the polarizer is preferably 10 to 60 μm, more preferably 20 to
It is 40 μm.

The polarizing plate of the present invention may be the polarizer itself, or may be one in which a transparent protective layer is provided on one side or both sides of the polarizer.

In the above-mentioned polarizing plate, the single-element transmittance corrected for luminosity is, for example, 45% or more. By using the polarizing plate having such characteristics, the display of the image display device can be brightened and the display quality can be improved. In the above-mentioned polarizing plate, the single-element transmittance corrected for luminosity is preferably 45.5% or more, and more preferably 46% or more. Further, the polarization degree of the polarizing plate is preferably 95% or more.

The protective layer is not particularly limited, and conventionally known transparent films can be used. For example, those having excellent transparency, mechanical strength, thermal stability, moisture barrier property, isotropic property, etc. are preferable. . Specific examples of the material of such a transparent protective layer include a cellulose-based resin such as triacetyl cellulose, a polyester-based, a polycarbonate-based, a polyamide-based, a polyimide-based, a polyether sulfone-based,
Examples thereof include transparent resins such as polysulfone-based, polystyrene-based, polynorbornene-based, polyolefin-based, acrylic-based, and acetate-based resins. Further, the above-mentioned acrylic, urethane-based, acrylic urethane-based, epoxy-based, silicone-based, etc. thermosetting resins or ultraviolet-curing resins are also included. Among these, a TAC film having a surface saponified with an alkali or the like is preferable from the viewpoint of polarization characteristics and durability.

Further, a polymer film described in JP 2001-343529 A (WO 01/37007) may be mentioned. Examples of the polymer material include a resin composition containing a thermoplastic resin having a substituted or unsubstituted imide group in the side chain and a thermoplastic resin having a substituted or unsubstituted phenyl group and a nitrile group in the side chain. Can be used, and examples thereof include a resin composition having an alternating copolymer of isobutene and N-methylenemaleimide and an acrylonitrile / styrene copolymer. The polymer film may be, for example, an extruded product of the resin composition.

The protective layer preferably has no color, for example. Specifically, the retardation value (Rth) in the film thickness direction represented by the following formula is -90 nm to +7.
It is preferably in the range of 5 nm, more preferably −
80 nm to +60 nm, particularly preferably -70 n
The range is from m to +45 nm. The phase difference value is -90n
Within the range of m to +75 nm, the coloring (optical coloring) of the polarizing plate due to the protective film can be sufficiently eliminated.
In the formula below, nx, ny, and nz represent the refractive indices of the protective layer in the three optical axis directions, respectively.
Specifically, the refractive index (nx,
The ny, nz) optical axis direction is indicated by an arrow. Refractive index nx, ny, nz
As described above, each represents the refractive index in the X-axis, Y-axis, and Z-axis directions, and as shown in the figure, the X-axis is the axial direction that exhibits the maximum in-plane refractive index, and the Y-axis is , Is an axial direction perpendicular to the X axis in the plane, and the Z axis is a thickness direction perpendicular to the X axis and the Y axis. d
Indicates the film thickness. Rth = {[(nx + ny) /
2] -nz} × d

Further, the transparent protective layer may further have an optical compensation function. As such a transparent protective layer having an optical compensation function, for example, for the purpose of preventing coloring or the like, or enlarging the viewing angle for good visual recognition, which is caused by a change in the viewing angle based on the phase difference in the liquid crystal cell. Known ones can be used. Specific examples include various stretched films obtained by uniaxially or biaxially stretching the transparent resin described above, oriented films such as liquid crystal polymers, and laminates in which an orientation layer such as liquid crystal polymers is arranged on a transparent substrate. To be Among these, because it is possible to achieve a wide viewing angle with good visibility,
An alignment film of the liquid crystal polymer is preferable, and in particular, an optical compensation retardation plate in which an optical compensation layer composed of a tilted alignment layer of a discotic or nematic liquid crystal polymer is supported by the above-mentioned triacetyl cellulose film is preferable. . Examples of such an optical compensation retardation plate include commercially available products such as "WV film" manufactured by Fuji Photo Film Co., Ltd. Incidentally, the optical compensation retardation plate,
It may be one in which optical properties such as retardation are controlled by laminating two or more film supports such as the above retardation film and triacetyl cellulose film.

The thickness of the transparent protective layer is not particularly limited and can be appropriately determined depending on, for example, the phase difference and the protective strength, but is usually 500 μm or less, preferably 5 to 3
00 μm, more preferably 5 to 150 μm

The transparent protective layer is a conventionally known method such as a method of applying the various transparent resins to a polarizing film or a method of laminating the transparent resin film or the optical compensation retardation plate on the polarizing film. Can be appropriately formed by the above method, or a commercially available product can be used.

The transparent protective layer may be further subjected to, for example, a hard coat treatment, an antireflection treatment, a treatment for the purpose of preventing or diffusing sticking, antiglare, or the like. The hard coat treatment is, for the purpose of preventing scratches on the surface of the polarizing plate, for example, a treatment of forming a cured film excellent in hardness and slipperiness, which is composed of a curable resin, on the surface of the transparent protective layer. Is. As the curable resin, for example, a silicone-based, urethane-based, acrylic-based, or epoxy-based UV-curable resin can be used, and the treatment can be performed by a conventionally known method. The prevention of sticking is intended to prevent adhesion with an adjacent layer. The antireflection treatment aims at preventing reflection of external light on the surface of the polarizing plate, and can be performed by forming a conventionally known antireflection layer or the like.

The antiglare treatment is intended to prevent visual interference of light transmitted through the polarizing plate due to reflection of external light on the surface of the polarizing plate. For example, the transparent protective layer of the transparent protective layer can be formed by a conventionally known method. This can be performed by forming a fine uneven structure on the surface. Examples of the method for forming such a concavo-convex structure include a surface roughening method such as a sandblast method and embossing, and a method of forming the transparent protective layer by blending transparent fine particles with the transparent resin as described above. To be

Examples of the transparent fine particles include silica, alumina, titania, zirconia, tin oxide, indium oxide, cadmium oxide, and antimony oxide. In addition to these, inorganic fine particles having conductivity, cross-linking or It is also possible to use organic fine particles composed of uncrosslinked polymer particles or the like. The average particle size of the transparent fine particles is not particularly limited, but is, for example, 0.5 to 50 μm.
The range is m. The blending ratio of the transparent fine particles is
Although not particularly limited, in general, the transparent resin 1 as described above is used.
The amount is preferably 2 to 50 parts by mass, more preferably 5 to 25 parts by mass, per 100 parts by mass.

The antiglare layer containing the transparent fine particles may be used as, for example, the transparent protective layer itself, or may be formed as a coating layer on the surface of the transparent protective layer. Further, the anti-glare layer may also serve as a diffusion layer (visual compensation function or the like) for diffusing the light transmitted through the polarizing plate and expanding the viewing angle. The antireflection layer, the sticking prevention layer, the diffusion layer, the antiglare layer, and the like are laminated on the polarizing plate separately from the transparent protective layer, for example, as an optical layer composed of a sheet or the like provided with these layers. You may.

The method for laminating the polarizer and the transparent protective layer and the like is not particularly limited, and a conventionally known method can be used. Generally, a pressure-sensitive adhesive, an adhesive, or the like can be used, and the type thereof can be appropriately determined depending on the material of each of the constituents. Examples of the adhesive include acrylic-based, vinyl alcohol-based, silicone-based, polyester-based, polyurethane-based and polyether-based polymer adhesives, and rubber-based adhesives. Further, an adhesive composed of a water-soluble crosslinking agent of vinyl alcohol-based polymer such as boric acid, borax, glutaraldehyde, melamine, oxalic acid, etc., an adhesive composed of isocyanate such as isocyanate or urethane, epoxy A system adhesive, an adhesive containing gelatin, or an adhesive containing at least a water-soluble crosslinking agent such as formaldehyde, glutaraldehyde, melamine, and oxalic acid can be used. The above-mentioned pressure-sensitive adhesives and adhesives are difficult to peel off even under the influence of humidity and heat, and have excellent light transmittance and polarization degree. In the present invention, an adhesive or an epoxy adhesive composed of isocyanate such as isocyanate or urethane is preferable. For example, when the polarizer is a PVA-based film, for example, from the viewpoint of stability of adhesion treatment, P
VA adhesives are preferred.

These adhesives or pressure-sensitive adhesives may be directly applied to the surface of the polarizer or the transparent protective layer, or a layer such as a tape or sheet composed of the above-mentioned adhesives or pressure-sensitive adhesives may be applied. It may be placed on the surface, or a solution of the adhesive or pressure-sensitive adhesive may be applied and dried to form a layer. In addition, for example, when prepared as an aqueous solution, other additives and a catalyst such as an acid may be added as necessary.

When the adhesive is applied, for example, other additives and a catalyst such as an acid may be added to the adhesive aqueous solution. The thickness of such an adhesive layer is
Although not particularly limited, it is, for example, 1 nm to 500 nm, preferably 10 nm to 300 nm, and more preferably 20 nm to 100 nm. Not particularly limited,
For example, a conventionally known method using an adhesive agent such as an acrylic polymer or vinyl alcohol polymer can be adopted. These adhesives can be used, for example, by applying an aqueous solution thereof to the surface of each constituent and drying it. Other additives and a catalyst such as an acid may be added to the aqueous solution, if necessary. Among these, a PVA-based adhesive is preferable as the adhesive because it has excellent adhesiveness to the PVA film.

In practical use, the polarizing plate of the present invention can be used as an optical member laminated with another optical layer. The optical layer is not particularly limited, but for example, for forming a liquid crystal display device such as a reflection plate, a semi-transmission plate, a retardation plate (including a wavelength plate such as 1/2 or 1/4), and a viewing angle compensation film. One or more suitable optical layers that may be used may be used, and in particular, a reflection plate or a semi-transmissive reflection plate is further laminated on the polarizing plate including the above-mentioned polarizer and protective layer of the present invention. Type polarizing plate or semi-transmissive polarizing plate, an elliptical polarizing plate or a circular polarizing plate in which a retardation plate is further laminated on a polarizing plate composed of the above-mentioned polarizer and a protective layer, and composed of the above-mentioned polarizer and a protective layer. A wide viewing angle polarizing plate in which a viewing angle compensation film is further laminated on the polarizing plate to be formed, or a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate composed of the above-mentioned polarizer and protective layer is preferable.

The reflective polarizing plate is a polarizing plate provided with a reflective layer, and is for forming a liquid crystal display device of the type that reflects incident light from the viewing side (display side) to display. Further, there is an advantage that a light source such as a backlight can be omitted and the liquid crystal display device can be easily thinned.
The reflective polarizing plate can be formed by an appropriate method such as a method in which a reflective layer containing a metal or the like is attached to one surface of the polarizing plate via a transparent protective layer or the like, if necessary.

Specific examples of the reflective polarizing plate include a transparent protective layer which is mat-treated if necessary, and a foil or vapor deposition film containing a reflective metal such as aluminum is attached to one surface of the transparent protective layer to form a reflective layer. can give. In addition, the transparent protective layer may contain fine particles to form a fine surface uneven structure, and a reflective layer having a fine uneven structure formed thereon. The reflective layer having the fine concavo-convex structure has the advantage that diffused incident light is diffused to prevent directivity and glare, and uneven brightness can be suppressed. In addition, the transparent protective layer containing fine particles has an advantage that incident light and reflected light thereof are diffused when they pass therethrough to further suppress uneven brightness. The reflective layer having a fine concavo-convex structure reflecting the surface fine concavo-convex structure of the transparent protective layer is formed by, for example, a vacuum deposition method,
It can be performed by an appropriate method such as an ion plating method, a vapor deposition method such as a sputtering method, a plating method, or the like, and a method of directly attaching a metal to the surface of the transparent protective layer.

The reflecting plate may be used as a reflecting sheet or the like in which a reflecting layer is provided on an appropriate film conforming to the transparent film instead of the method of directly applying to the transparent protective layer of the polarizing plate. Since the reflective layer usually contains a metal, a mode in which the reflective surface is used in a state of being covered with a transparent protective layer, a polarizing plate or the like is used to prevent a decrease in reflectance due to oxidation, and thus to maintain the initial reflectance for a long time. And the point of avoiding the additional provision of the protective layer.

The semi-transmissive polarizing plate can be obtained by using the above-mentioned semi-transmissive reflective layer such as a half mirror that reflects and transmits light by the reflective layer. The semi-transmissive polarizing plate is usually provided on the back side of the liquid crystal cell, and when the liquid crystal display device is used in a relatively bright atmosphere,
An image is displayed by reflecting incident light from the viewing side (display side), and in a relatively dark atmosphere, an image is displayed using a built-in light source such as a backlight built into the back side of the semi-transmissive polarizing plate. It is possible to form a liquid crystal display device of the type that displays That is, the semi-transmissive polarizing plate is useful for forming a liquid crystal display device of a type that can save energy for using a light source such as a backlight in a bright atmosphere and can be used with a built-in light source in a relatively dark atmosphere. Is.

Next, an elliptically polarizing plate or a circularly polarizing plate in which a retardation plate is further laminated on the above-mentioned polarizing plate composed of a polarizer and a protective layer will be described.

A phase difference plate or the like is used when changing linearly polarized light into elliptically polarized light or circularly polarized light, changing elliptically polarized light or circularly polarized light into linearly polarized light, or changing the polarization direction of linearly polarized light. As a retardation plate that converts the circularly polarized light into circularly polarized light or the circularly polarized light into linearly polarized light, the so-called 1 /
A four-wave plate (also called a λ / 4 plate) is used. A half-wave plate (also called a λ / 2 plate) is usually used when changing the polarization direction of linearly polarized light.

The elliptically polarizing plate compensates (prevents) coloring (blue or yellow) generated by the birefringence of the liquid crystal layer of a spurts twist nematic (STN) type liquid crystal display device, and is used for black and white display without the coloring. Used effectively. Furthermore, 3
It is preferable to control the dimensional refractive index because it is possible to compensate (prevent) coloring that occurs when the screen of the liquid crystal display device is viewed from an oblique direction. The circularly polarizing plate is effectively used, for example, when adjusting the color tone of an image of a reflective liquid crystal display device in which an image is displayed in color, and also has a function of preventing reflection.

Specific examples of the above-mentioned retardation plate include polycarbonate, polyvinyl alcohol, polystyrene,
Polymethylmethacrylate, polypropylene and other polyolefins, polyarylate, a birefringent film obtained by stretching a film produced from a suitable polymer such as polyamide, an oriented film of a liquid crystal polymer,
Examples thereof include those in which an alignment layer of a liquid crystal polymer is supported by a film. The retardation plate may be one having an appropriate retardation according to the purpose of use, for example, one for the purpose of compensating for coloring or viewing angle by birefringence of various wave plates or liquid crystal layers, and may be two or more kinds. It may be one in which retardation plates are laminated to control optical properties such as retardation.

The elliptically polarizing plate or the reflection type elliptically polarizing plate is a laminate of a polarizing plate or a reflection type polarizing plate and a retardation plate in an appropriate combination. Such an elliptically polarizing plate or the like may be formed by sequentially stacking them separately in the manufacturing process of a liquid crystal display device so as to form a combination of a (reflection type) polarizing plate and a retardation plate. An optical member such as an elliptically polarizing plate is excellent in stability of quality and workability of stacking, and has an advantage that manufacturing efficiency of a liquid crystal display device can be improved.

Next, a wide viewing angle polarizing plate in which a viewing angle compensating film is further laminated on the polarizing plate including the above-mentioned polarizer and protective layer will be described.

The viewing angle compensating film is a film for widening the viewing angle so that the image can be seen relatively clearly even when the screen of the liquid crystal display device is viewed from a slightly oblique direction, not perpendicular to the screen.

Examples of such a viewing angle compensating film include a retardation film, an alignment film such as a liquid crystal polymer,
Examples include those in which an alignment layer such as a liquid crystal polymer is supported on a transparent substrate. The ordinary retardation plate is made of a birefringent polymer film uniaxially stretched in the plane direction, whereas the retardation plate used as a viewing angle compensation film is biaxially stretched in the plane direction. A polymer film having birefringence, a polymer having birefringence in which the refractive index in the thickness direction is uniaxially stretched in the plane direction and is also stretched in the thickness direction, and a bidirectionally stretched film such as a tilted orientation film. Is used. Examples of the tilted oriented film include those obtained by adhering a heat-shrinkable film to a polymer film and subjecting the polymer film to stretching treatment and / or shrinking treatment under the action of the shrinkage force caused by heating, and those obtained by obliquely orienting a liquid crystal polymer. Can be mentioned. The raw material polymer of the retardation plate is the same as the polymer explained in the previous retardation plate, which prevents coloration due to the change of the viewing angle due to the phase difference due to the liquid crystal cell and enlarges the viewing angle for good viewing. An appropriate one can be used for the purpose such as.

From the viewpoint of achieving a wide viewing angle for good visibility, an optically anisotropic layer including a liquid crystal polymer alignment layer, particularly a discotic liquid crystal polymer tilted alignment layer, was supported by a triacetyl cellulose film. An optical compensation retardation plate is preferably used.

Next, a polarizing plate in which a brightness enhancement film is further laminated on the polarizing plate composed of the above-mentioned polarizer and protective layer will be described.

The polarizing plate in which the polarizing plate and the brightness enhancement film are bonded together is usually used by being provided on the back side of the liquid crystal cell. The brightness enhancement film has a property of reflecting linearly polarized light of a predetermined polarization axis or circularly polarized light of a predetermined direction when natural light is incident due to reflection from a backlight of a liquid crystal display device or the back side, and transmits other light. Therefore, the polarizing plate in which the brightness enhancement film is laminated on the polarizing plate including the above-mentioned polarizer and the protective layer, makes light from a light source such as a backlight incident to obtain transmitted light in a predetermined polarized state, and Light other than the predetermined polarization state is reflected without being transmitted. The light reflected by the surface of the brightness enhancement film is inverted through a reflection layer or the like provided on the rear side of the brightness enhancement film to be re-incident on the brightness enhancement film, and part or all of the light is transmitted as light in a predetermined polarization state to achieve brightness. Increase the amount of light that passes through the enhancement film. At the same time, by supplying polarized light that is difficult to be absorbed by the polarizer to increase the amount of light that can be used for liquid crystal display image display, etc.,
The brightness can be improved. That is, when light is incident from the back side of the liquid crystal cell through a polarizer in a backlight without using a brightness enhancement film, light having a polarization direction that does not match the polarization axis of the polarizer is almost polarized. It is absorbed by the child and does not pass through the polarizer. That is, it depends on the characteristics of the used polarizer, but it is about 5
0% of the light is absorbed by the polarizer, and the amount of light that can be used for displaying the liquid crystal image is reduced accordingly, and the image becomes dark.

In the brightness enhancement film, light having a polarization direction that is absorbed by the polarizer is first reflected by the brightness enhancement film without being made incident on the polarizer, and then the light is passed through a reflection layer or the like provided on the rear side thereof. It is repeated by reversing and re-incident on the brightness enhancement film. Only the polarized light that is reflected and inverted between the two and has a polarization direction that allows the light to pass through the polarizer is transmitted through the brightness enhancement film and supplied to the polarizer. The light can be efficiently used for displaying an image on the liquid crystal display device, and the screen can be brightened. The brightness enhancement film has a property of transmitting linearly polarized light of a predetermined polarization axis and reflecting other light, such as a multilayer thin film of a dielectric or a multilayer stack of thin films having different refractive index anisotropies. , A cholesteric liquid crystal layer, in particular, an oriented film of a cholesteric liquid crystal polymer or one in which the oriented liquid crystal layer is supported on a film substrate, such that it reflects either left-handed or right-handed circularly polarized light Appropriate ones such as those showing a property of transmitting light can be used.

Therefore, in the brightness enhancement film of the type which transmits the linearly polarized light of the above-mentioned predetermined polarization axis, the transmitted light is directly incident on the polarizing plate with the polarization axis aligned to suppress the absorption loss by the polarizing plate. It can be efficiently transmitted. On the other hand, in a brightness enhancement film of a type that transmits circularly polarized light like a cholesteric liquid crystal layer, it can be directly incident on a polarizer, but from the viewpoint of suppressing absorption loss, the circularly polarized light is linearly polarized through a retardation plate. It is preferable that the light is converted to be incident on the polarizing plate. By using a ¼ wavelength plate as the retardation plate, circularly polarized light can be converted into linearly polarized light.

The retardation plate functioning as a quarter-wave plate in a wide wavelength range such as a visible light region is, for example, a retardation layer functioning as a quarter-wave plate with respect to a light of a wavelength of 550 nm and another retardation film. It can be obtained by a method of superposing a retardation layer exhibiting characteristics, for example, a retardation layer functioning as a half-wave plate. Therefore, the retardation plate disposed between the polarizing plate and the brightness enhancement film may include one or more retardation layers.

As for the cholesteric liquid crystal layer,
By combining two or more layers having different reflection wavelengths to form an arrangement structure in which two or more layers are superposed, a circularly polarized light can be obtained in a wide wavelength range such as a visible light region, and based on that, transmission in a wide wavelength range can be obtained. Circularly polarized light can be obtained.

Further, the polarizing plate of the present invention may include one in which a polarizing plate and two or more optical layers are laminated, like the above-mentioned polarization separation type polarizing plate. Therefore, it may be a reflective elliptical polarizing plate or a semi-transmissive elliptical polarizing plate in which the above reflective polarizing plate or semi-transmissive polarizing plate is combined with a retardation plate. The optical member in which two or more optical layers are laminated can be formed by a method of sequentially laminating the optical members in a manufacturing process of a liquid crystal display device or the like. The optical member obtained by laminating the optical layers in advance has excellent quality stability and assembling work, and has an advantage that the manufacturing process of the liquid crystal display device can be improved. Appropriate adhesion means such as an adhesive layer may be used for lamination. When the above-mentioned polarizing plate and other optical members are adhered, their optical axes can be arranged at appropriate angles according to the intended retardation characteristics and the like.

The polarizing plate and the optical member described above may be provided with an adhesive layer for adhering to other members such as a liquid crystal cell. For its formation, for example, an adhesive substance or an adhesive agent containing an appropriate polymer such as an acrylic polymer or silicone polymer, polyester or polyurethane, polyamide or polyether, or a suitable polymer such as fluorine or rubber can be used. There is no particular limitation. Among them, acrylic pressure-sensitive adhesives are preferable because they are excellent in optical transparency, exhibit appropriate wettability, cohesiveness, and adhesiveness adhesiveness, and are excellent in weather resistance and heat resistance.

In addition to the above, prevention of foaming phenomenon and peeling phenomenon due to moisture absorption, deterioration of optical characteristics due to difference in thermal expansion and prevention of warpage of liquid crystal cells, and further formation of a liquid crystal display device of high quality and excellent durability, etc. From this point of view, an adhesive layer having a low moisture absorption rate and excellent heat resistance is preferable.

The adhesive layer is made of, for example, natural or synthetic resins, particularly tackifying resin, glass fiber, glass beads,
Appropriate additives that may be added to the adhesive layer, such as fillers containing metal powder and other inorganic powders, pigments, colorants, antioxidants, etc., may be contained. Further, it may be an adhesive layer containing fine particles and exhibiting light diffusion property.

The adhesive layer may be attached to one side or both sides of the polarizing plate or the optical member by an appropriate method. As an example, an adhesive substance or a composition thereof is dissolved or dispersed in a solvent containing a single solvent or a mixture of appropriate solvents such as toluene and ethyl acetate to prepare an adhesive liquid of about 10 to 40% by weight. Then, a method of directly attaching it onto the optical member by an appropriate developing method such as a casting method or a coating method, or a method of forming an adhesive layer on the separator and transferring it onto the optical member according to the above And so on.

The pressure-sensitive adhesive layer may be provided on one side or both sides of the polarizing plate or the optical member as a superposed layer of different compositions or types. Further, when it is provided on both sides, an adhesive layer having different composition, type, thickness, etc. can be formed on the front and back of the optical member. The thickness of the pressure-sensitive adhesive layer can be appropriately determined depending on the purpose of use and the adhesive strength, and is generally 1 to 500 μm, preferably 5 to 200 μm, and particularly preferably 10 to 100 μm.
m.

The exposed surface of the adhesive layer is temporarily covered with a separator for the purpose of preventing its contamination or the like until it is put into practical use. As a result, it is possible to prevent contact with the adhesive layer in the usual handling state. As a separator,
As long as the above thickness condition is satisfied, an ordinary one can be used. As the separator, for example, a suitable thin sheet such as a plastic film or a rubber sheet, paper or cloth, a non-woven fabric or net, a foamed sheet or a metal foil, or a laminated body thereof,
If necessary, a suitable one in accordance with the prior art, such as one coated with a suitable release agent such as silicone, long-chain alkyl, fluorine, molybdenum sulfide, etc., may be used.

In the present invention, each layer such as the polarizer and the transparent protective layer forming the above-mentioned polarizing plate or optical member, and the adhesive layer is, for example, a salicylic acid ester compound, a benzophenol compound, a benzotriazole compound,
It may be one which has been given an ultraviolet absorbing ability by an appropriate method such as a method of treating with an ultraviolet absorber such as a cyanoacrylate compound or a nickel complex salt compound.

The polarizing plate of the present invention can be preferably used for forming various devices such as liquid crystal display devices. Therefore, a liquid crystal display device including the liquid crystal panel and the polarizer is provided. Further, a liquid crystal display device including a liquid crystal panel and the polarizing plate is also provided. The liquid crystal display device can be formed in a conventional manner. That is, a liquid crystal display device is generally formed by appropriately assembling components such as a liquid crystal panel, a polarizing plate, an optical compensation retardation plate, and an illumination system as necessary, and incorporating a drive circuit. The invention is not particularly limited except that the polarizer or the polarizing plate according to the invention is used, and can be in accordance with the conventional one. As for the liquid crystal panel, for example, TN type or STN type,
Any type such as π type can be used.

Therefore, it is possible to form an appropriate liquid crystal display device such as a liquid crystal display device in which a polarizer or a polarizing plate is arranged on one side or both sides of a liquid crystal panel, or one using a backlight or a reflector in an illumination system. . In that case, the polarizer or the polarizing plate according to the present invention can be installed on one side or both sides of the liquid crystal panel.

The type of the liquid crystal panel forming the liquid crystal display device can be arbitrarily selected. For example, an active matrix drive type represented by a thin film transistor type, a simple matrix represented by a twist nematic type or a super twist nematic type. Various types of liquid crystal cells such as a driving type can be used. Among these, the optical film and the polarizing plate of the invention are particularly VA (vertical alignment; Vertical
Alighned) is very good for optical compensation of cells,
It is very useful as a viewing angle compensation film for a VA mode liquid crystal display device.

The liquid crystal panel usually has a structure in which liquid crystal is injected into the gap between the liquid crystal cell substrates facing each other.
The liquid crystal cell substrate is not particularly limited, for example,
A glass substrate or a plastic substrate can be used. The material of the plastic substrate is not particularly limited,
Conventionally known materials can be used.

When a polarizing plate and optical members are provided on both sides of the liquid crystal panel, they may be of the same type,
It may be different. Further, when forming the liquid crystal display device, for example, one or more appropriate layers such as a prism array sheet, a lens array sheet, a light diffusing plate, and a backlight can be arranged at appropriate positions.

Further, the liquid crystal display device of the present invention includes a liquid crystal panel and is not particularly limited except that the polarizer or polarizing plate of the present invention is used as the polarizer or polarizing plate.
Further, when the light source further has a light source, it is not particularly limited, but for example, a plane light source that emits polarized light is preferable because light energy can be effectively used.

In the liquid crystal display device of the present invention, for example, a diffusion plate, an anti-glare layer, an antireflection film, a protective layer, a protective plate, a prism array or a lens sheet, a light diffusion plate or a back is further provided on the polarizing plate on the viewing side. One or more layers of components such as lights may be arranged at appropriate positions, or a compensating retardation plate or the like may be appropriately arranged between the liquid crystal cell and the polarizing plate in the liquid crystal panel.

Next, a liquid crystal display device in which the polarizer or polarizing plate of the present invention is preferably used will be described. Such a liquid crystal display device is a liquid crystal display device including a light source, a light control layer, and a liquid crystal panel. A light source for illuminating the inside of the liquid crystal display device is arranged on at least one side surface of the liquid crystal panel. In the device, a light control layer that reflects the light emitted from the light source that is transmitted inside the liquid crystal display device is disposed on one surface of the liquid crystal panel. The liquid crystal display device using the polarizer or polarizing plate of the present invention may be any liquid crystal display device having a conventionally used configuration.

The light source is not particularly limited as long as it can illuminate the inside of the liquid crystal display device, and examples thereof include a point light source, a linear light source, a cold cathode tube, an LED and the like.

The material of the light control layer is not limited. For example, an ultraviolet curable resin or monomer, or a thermoplastic resin may be used. When a base film is used, this base film may be peeled off. Further, if necessary, an adhesive, particularly a pressure-sensitive adhesive or the like can be applied or transferred onto the surface opposite to the light reflecting means to form it.

The method for producing the light control layer is not particularly limited. For example, a method of pressure-transferring a shape previously formed in a mold on a transparent film, a method of applying an ultraviolet curable resin to the mold and curing / peeling it, after applying an ultraviolet curable resin to the film in advance, A method of pressing a mold against the surface coated with the resin, irradiating it with ultraviolet rays to cure it and peeling it off can be mentioned. Here, an ultraviolet curable resin is given as an example, but an ultraviolet curable monomer or a resin curable by radiation such as an electron beam may be used instead.

The light control layer of the present invention is much thinner than the light guide plate used in the backlight or front light system of the conventional liquid crystal display device, and can make the liquid crystal display device thinner. Specifically, the thickness of the light control layer is 200 μm or less, preferably 100 μm.
It is the following. Therefore, it can be made significantly thinner than the conventional backlight or front light system having a thickness of 2 mm or more.

The light control layer may have a plurality of light reflecting means on its surface. The light reflecting means includes, for example, a concave shape having an inclined surface. When the light transmitted inside the liquid crystal display device is incident on the concave light reflecting means of the light control layer, the light can be reflected inside the liquid crystal display device according to the angle of the slope. Therefore, the light reflecting means can prevent the transmitted light inside the liquid crystal display device from being emitted to the outside and can assist the internal transmission.

It is preferable to provide light source reflecting means around the light source of the present invention. That is, by providing the light source reflecting means in close contact with the side surface of the liquid crystal panel so as to surround the light source, the light from the light source can be effectively incident on the liquid crystal panel, and bright illumination can be expected. The light source reflecting means may be a reflective film in which a metal thin film having good reflectivity is appropriately formed, a white film, a metal plate, or a resin molded product.

According to the present invention, a liquid crystal panel, the above-mentioned polarizer, a light source for illuminating the inside of the liquid crystal display device, and a light control layer for reflecting the light emitted from the light source for transmitting inside the liquid crystal panel are provided. A light source is disposed on at least one side surface of the liquid crystal panel, and a light control layer is disposed on one surface of the liquid crystal panel.
There is provided a liquid crystal display device in which a polarizer is located between the liquid crystal panel and the light control layer. There is also provided a liquid crystal display device including the polarizing plate of the present invention in place of the above polarizer.

According to the present invention, there is provided a liquid crystal display device further including a retardation plate, wherein the retardation plate is located between the polarizer and the liquid crystal panel. There is also provided a liquid crystal display device that includes the polarizing plate of the present invention in place of the polarizer, and the retardation plate is located between the polarizing plate and the liquid crystal panel.

FIG. 2 is a sectional view of an example of the reflection type liquid crystal display device of the present invention. As shown, this liquid crystal display device 1
01 includes a liquid crystal panel 100, a light source 51, and a light control layer 40. The light source 51 is arranged on one side surface (left side in FIG. 2) of the liquid crystal panel 100. Light source 5
The light source reflection means 52 covers the periphery of 1 except for the area in contact with the side surface of the liquid crystal panel 100.

The liquid crystal panel 100 includes the upper transparent substrate 20.
And a lower substrate 10a and a liquid crystal layer 30. A low refractive index layer 24, a color filter 23, a transparent electrode 21, and a rubbing film 22 are laminated in this order on one surface of the upper transparent substrate 20. These are arranged with one end surface aligned with one end surface of the upper transparent substrate 20. The reflective electrode 11 and the rubbing film 12 are formed on the lower substrate 10a.
Are stacked in this order. These are arranged with both ends aligned with the lower substrate 10a. Upper transparent substrate 2
0 rubbing film 22 and lower substrate 10a rubbing film 12
Are arranged to face each other. Peripheral surfaces of the two substrates facing each other are sealed with a sealing material 31 except for a part thereof. Liquid crystal is injected into a space formed by the sealing material 31, the upper transparent substrate 20, and the lower substrate 10a to form the liquid crystal layer 30. In addition, all layers of the liquid crystal panel are arranged with both ends aligned except for the upper transparent substrate 20. One end face of the upper transparent substrate 20 is arranged with its end aligned with the other layers, but the other end face (the left side face in FIG. 2) projects.

A light control layer 40 is laminated on the surface of the upper transparent substrate 20 of the liquid crystal panel 100. Between the light control layer 40 and the upper transparent substrate 20, the retardation plate 26, the polarizing plate 25, and the adhesive layer 28 are provided on the upper transparent substrate 2
They are arranged in this order from 0. The surface of the light control layer 40 has a light reflection means A, and the light reflection means A
Has a plurality of slopes A1. The shape of the cross section of the slope A1 is a substantially isosceles triangle. The light control layer 40, the retardation film 26, the polarizing plate 25, and the adhesive layer 28 are laminated with their both ends aligned, but since the surface area is smaller than that of the upper transparent substrate 20, one end surface of them is of the upper transparent substrate 20. Not aligned with either end face.

The light emitted from the light source 51 is reflected by the light source reflection means 5
2, most of the light is incident on the upper transparent substrate 20 based on the thickness ratio. The incident light is transmitted inside the liquid crystal display device 101 while being totally reflected based on the law of refraction. When optically transmitting the inside of the liquid crystal display device 101, the light control layer 40, the adhesive layer 28, and the upper transparent substrate 20.
The low-refractive-index layer 24 having a refractive index sufficiently smaller than the refractive index of 1 reflects the transmitted light at the interface between the upper transparent substrate 20 and the low-refractive-index layer 24. Therefore, it is possible to prevent light from reaching the color filter 23 or the liquid crystal layer 30 and losing light. When the low refractive index layer 24 has a sufficient thickness, the transmitted light can be totally reflected at the interface between the upper transparent substrate 20 and the low refractive index layer 24.

Further, the light control layer 40, the adhesive layer 28 and the upper transparent substrate 2 such that the difference in refractive index between the light control layer 40 and the adhesive layer 28 and the upper transparent substrate 20 is small.
If it is a combination of 0 or a combination of the light control layer 40 and the adhesive layer 28 having a high refractive index, the light transmitted inside the upper transparent substrate 20 is the phase difference plate 26 and the polarizing plate 2.
5 and the adhesive layer 28, and the light control layer 40
To reach. When light is incident on the slope A1 of the light reflection means A provided on the light control layer 40, the light is reflected according to the angle of inclination of the slope A1, and the light does not pass through the light control layer 40 and is directed toward the upper transparent substrate 20. To go out. That is,
The light emitted from the light source 51 and incident on the upper transparent substrate 20 is totally reflected at the interface between the light control layer 40 and the air on the one hand, and at the interface between the low refractive index layer 24 and the upper transparent substrate 20 on the other hand, Light can reach the side surface (right side surface in FIG. 2) of the upper transparent substrate 20 opposite to the side surface on which the light source 51 is arranged.

The liquid crystal display device 1 in which light is transmitted in this way
When the polarizing plate of the present invention is used as the polarizing plate 25 inside 01, the light emitted from the light source 51 is transmitted one or more times when the light is transmitted, but another side surface of the upper transparent substrate 20 (see FIG. 2). It is possible to suppress coloring of the transmitted light emitted from the right side surface).

FIG. 3 is a sectional view of an example of the semi-transmissive liquid crystal display device of the present invention. As shown, the liquid crystal display device 201 includes a liquid crystal panel 200, a light source 51, and a light control layer 40. The light source 51 is arranged on one side surface (left side in FIG. 3) of the liquid crystal panel 200. The light source reflection means 52 is further arranged in a region other than the area around the light source 51 and in contact with the side surface of the liquid crystal panel 200.

The liquid crystal panel 200 includes the upper transparent substrate 20.
And a lower transparent substrate 10 and a liquid crystal layer 30. The color filter 2 is provided on one surface of the upper transparent substrate 20.
3, the transparent electrode 21, and the rubbing film 22 are laminated in this order. These are arranged with both ends aligned with one end surface of the upper transparent substrate 20. On the lower transparent substrate 10, the low refractive index layer 14, the semi-transmissive reflective electrode 13 and the rubbing film 12 are laminated in this order. These are arranged such that one end face thereof is aligned with the lower transparent substrate 10. The rubbing film 22 of the upper transparent substrate 20 and the rubbing film 12 of the lower transparent substrate 10 are arranged to face each other. Peripheral surfaces of the two substrates facing each other are sealed with a sealing material 31 except for a part thereof. A liquid crystal is injected into a space formed by the sealing material 31, the upper transparent substrate 20, and the lower transparent substrate 10 to form the liquid crystal layer 30. All the layers of the liquid crystal panel are arranged with their ends aligned except the lower transparent substrate 10. One end surface of the lower transparent substrate 10 is arranged with its end aligned with the other layers, but the other end surface (the left side surface in FIG. 3) projects.

A light control layer 40 is laminated on the surface of the lower transparent substrate 10 of the liquid crystal panel 200. Between the light control layer 40 and the lower transparent substrate 10, the retardation plate 16, the polarizing plate 15 and the adhesive layer 18 are provided on the lower transparent substrate 1
They are arranged in this order from 0. The surface of the light control layer 40 has a reflection layer 60 and a light reflection means A,
The light reflecting means A has a plurality of slopes A1. The slope A1 is
The shape of the cross section is substantially an isosceles triangle. The light control layer 40, the retardation plate 16, the polarizing plate 15 and the adhesive layer 18 are
Although they are laminated with both ends aligned, their size is smaller than that of the lower transparent substrate 10, so that one end face thereof is not aligned with any one end face of the lower transparent substrate 10.

The light emitted from the light source 51 is reflected by the light source reflection means 5
2, most of the light is incident on the lower transparent substrate 10 based on the thickness ratio. The incident light is transmitted inside the liquid crystal display device 201 while being totally reflected based on the law of refraction.

When optically transmitting the inside of the liquid crystal display device 201, the low refractive index layer 14 having a refractive index sufficiently smaller than the refractive index of the light control layer 40, the adhesive layer 18 and the lower transparent substrate 10 is used for transmitting light. Is reflected at the interface between the lower transparent substrate 10 and the low refractive index layer 14. Therefore, it is possible to prevent light from reaching the color filter 23 or the liquid crystal layer 30 and losing light. Further, the low refractive index layer 14 having a sufficient thickness
Can totally reflect the transmitted light at the interface between the lower transparent substrate 10 and the low refractive index layer 14.

Further, the light control layer 40, the adhesive layer 18 and the lower transparent substrate 1 such that the difference in the refractive index between the light control layer 40 and the adhesive layer 18 and the lower transparent substrate 10 is small.
If it is a combination of 0 or a combination of the light control layer 40 and the adhesive layer 18 having a high refractive index, the light transmitted inside the lower transparent substrate 10 is the retardation plate 16 and the polarizing plate 1.
5 and the adhesive layer 18, and the light control layer 40
To reach. When light is incident on the slope A1 of the light reflecting means A provided on the light control layer 40, the light is reflected according to the angle of inclination of the slope A1, and the light does not pass through the light control layer and is directed toward the lower transparent substrate 10. To go out. Therefore, the light source 5
The light that has exited 1 and is incident on the lower transparent substrate 10 is totally reflected at the interface between the light control layer 40 and the air on the one hand, and at the interface between the low refractive index layer 14 and the lower transparent substrate 10 on the other hand. ,
Light can reach the side surface (the right side surface in FIG. 3) of the lower transparent substrate 10 opposite to the side surface on which the light source 51 is arranged.

The liquid crystal display device 2 in which light is transmitted in this way
When the polarizing plate of the present invention is used as the polarizing plate 15 inside 01, the light emitted from the light source 51 is transmitted once or more when the light is transmitted, but another side surface of the lower transparent substrate 10 (see FIG. It is possible to suppress coloring of the transmitted light emitted from the right side surface).

FIG. 4 is a sectional view of an example of the transmission type liquid crystal display device of the present invention. As shown in the figure, the liquid crystal panel 300 and the transmissive liquid crystal display device 301 include a transflective electrode 13
3 has the same configuration as that of the liquid crystal panel 200 and the liquid crystal display device 201 shown in FIG.

The method of transmitting the transmitted light emitted from the light source 51 inside the liquid crystal display device 301 is the same as that of the semi-transmissive liquid crystal display device 201. Therefore, the liquid crystal display device 301
When the polarizing plate of the present invention is used as the polarizing plate 15 inside,
When the light is transmitted, the light emitted from the light source 51 is transmitted once or more, but it is possible to suppress coloring of the transmitted light emitted from another side surface (the right side surface in FIG. 4) of the lower transparent substrate 10. .

2 to 4, when the light-reflecting means A is not a continuous surface in the lengthwise direction but is a dent defined by a predetermined length, depth and width, the length of the dent The light reflecting means A having a depth of 5 times or more the depth can reflect light efficiently. In addition, in FIGS.
The length of the light reflecting means A is the length in the left-right direction, the depth is the length in the vertical direction, and the width is the length in the direction perpendicular to the length and the depth. At this time, the length of the light reflecting means is preferably 500 μm or less in terms of uniform light emission.

Further, when the light reflecting means A is a concave or convex prism having a slant surface facing at least the light source side and having an angle of 35 ° or more and 48 ° or less, the light reflecting means transmits the light transmitted inside the liquid crystal panel. Since the light can be directed toward the liquid crystal panel based on the reflection on the slope of A, a large amount of light that substantially contributes to the display can be emitted, and a bright and excellent display can be obtained. Especially in the above angle range, the light reflecting means A
The transmitted light can be reflected to the observer very efficiently by the total reflection based on the refractive index of the inclined surface.

If the angle of at least the inclined surface of the light reflecting means facing the light source side is 35 ° or more with respect to the liquid crystal panel surface, the angle of the light emitted by illuminating the liquid crystal panel and reflected by the reflecting surface is 30. It is preferable because it does not exceed 0 ° and faces the observer. If the angle of the slope of the light reflecting means facing at least the light source side is 48 ° or less with respect to the liquid crystal panel surface,
It is preferable because it can be totally reflected and light leakage from the slope does not occur. The angle of the slope of the light reflecting means is related to the refractive index of the light reflecting means, but is preferably 38 ° or more and 45 ° or more.
Below, if it is more preferably 40 ° or more and 44 ° or less, the emission direction can be made more vertical, the direction of the observer can be efficiently directed, and the loss can be reduced, so that the light can be emitted efficiently. You can

At this time, it is preferable in terms of scratch resistance that the prism is a concave portion having a substantially triangular cross section.

When the light sources are provided on a plurality of side surfaces of the liquid crystal panel, the slopes of the respective light reflecting means may be directed to any of the light sources. Further, when the light sources are provided so as to face each other with the liquid crystal panel sandwiched between them, it is also possible to provide an inclined surface facing the respective light sources in one light reflecting means so as to face each other. In that case, the cross-sectional shape of the light reflecting means may be a substantially triangular shape, a substantially quadrangular shape, or a substantially pentagonal shape.

In the light control layer having the light reflecting means, except for the portion other than the light reflecting means or the slope facing the light source side of the light reflecting means, a flat surface having an angle of 5 ° or less, preferably 0 ° with respect to the liquid crystal panel surface. Alternatively, it is preferable that the liquid crystal panel is formed of an inclined surface facing away from the light source and having an angle of 35 ° or more with respect to the liquid crystal panel surface. With such an angle configuration, most of the light control layer can have a surface with an angle of 5 ° or less, and the light transmitted inside the liquid crystal display device can be efficiently transmitted away from the light source. Therefore, uniform light emission can be realized.

If the change in the angle of the flat surface adjacent between the light reflecting means and the means is as small as possible, the disturbance of the display image can be reduced. The change in angle between adjacent flat surfaces is preferably within 1 °, more preferably within 0.5 °.

It is a concave portion defined by the length, depth and width, whose cross section in the depth / width direction is a substantially triangular shape, and the minute prismatic dents whose length is 5 times or more of the depth reflect light. In the case of an LCD having a light control layer formed as a means, if the arrangement of the fine prismatic dents is random and the density is high on the side opposite to the light incident part or in the vicinity of the side surface, the fine prismatic dents can be formed between the pixel and the fine prismatic dent It is possible to prevent moire that occurs and realize a more uniform screen display.

When the light reflecting means formed in the light control layer is discontinuous and has a substantially triangular cross section, the surface facing the slope of the light reflecting means is viewed from above in terms of the light transmittance in the reflection mode. It is preferable to reduce the area. Therefore, the angle with the liquid crystal panel is preferably as large as possible, specifically 50 ° or more, preferably 60 ° or more, more preferably 75 ° or more.

Further, on the surface of the light reflection means of the light control layer, the function of the light reflection means is not hindered,
A reflective layer and an antiglare layer may be formed. The reflective layer has a function of reflecting external light and displaying without turning on the light source,
It is formed from aluminum, silver or the like by vapor deposition or sputtering.

The low refractive index layer is arranged on one surface of the liquid crystal panel, but is preferably arranged on the surface on which the light control layer is not provided. The low refractive index layer is more preferably arranged between the liquid crystal layer and the upper or lower transparent substrate of the liquid crystal panel on which the light source is arranged on one side surface. With the low-refractive index layer arranged in this way, of the light that is incident from the light source and is transmitted inside the liquid crystal display device, the light that goes toward the liquid crystal layer is reduced by total reflection based on the refractive index difference with the low-refractive index layer. It can be reflected at the interface between the layer and the substrate. Therefore, the light transmitted inside the liquid crystal display device can eliminate the influence of birefringence or scattering of the liquid crystal layer, or light absorption by a color filter or the like provided near the liquid crystal layer,
Good transmission is possible. As a result, abrupt decrease of transmitted light due to light absorption by color filters, etc., and decrease of transmitted light due to partial change of birefringence or light scattering due to display of liquid crystal layer and occurrence of non-uniformity are suppressed. It is possible to suppress the occurrence of a ghost phenomenon that affects the liquid crystal panel portion that is distant from the light source.

Such a low-refractive index layer has almost no effect on the external light incident in the reflection mode. For example, even if the low refractive index layer has a refractive index difference of 0.1 with the transparent substrate on which the light source is arranged on one side surface, the reflectance at the interface between the transparent substrate and the low refractive index layer is at most 0. It is about 1%. Therefore, the darkness of the screen display and the reduction of the contrast due to the reflection loss of the external light do not occur.

The reflection at the interface between the low refractive index layer and the transparent substrate is
The smaller the refractive index of the low refractive index layer is than the refractive index of the transparent substrate, the greater the degree of reflection. The refractive index difference is, for example, 0.05 or more, preferably 0.1 or more.

The material and manufacturing method of the low refractive index layer are not particularly limited. For example, a method of forming an inorganic or organic low-refractive index dielectric material on a transparent substrate by vacuum vapor deposition, or a method of applying it by spin coating is used.

The thicker the low refractive index layer, the higher the light reflection effect. Specifically, for the visible light wavelength defined from 380 nm to 780 nm, the optical path length calculated by at least the refractive index × film thickness should be ¼ wavelength or more, that is, 95 nm or more for the short wavelength side wavelength of 380 nm. A light reflection effect can be obtained. More effectively 1/2 wavelength or more, that is, 1
90 nm or more, preferably one wavelength or more, that is, 380 n
m or more, and more preferably 600 nm or more.

The refractive index of the low refractive index layer is preferably lower than that of the light control layer. The refractive index difference is, for example, 0.05 or more, preferably 0.1 or more. In addition, the refractive index of the transparent substrate on which the light control layer and the light source are arranged on one side surface is higher than that of the substrate, for example, within 0.05.

The light control layer may be a transparent film. In this case, the light control layer is attached to the surface of the liquid crystal panel via an adhesive layer, but it is possible to efficiently guide light to the light control layer by using an adhesive layer having a refractive index larger than that of the low refractive index layer. it can. Therefore, the light is reflected by the inclined surface of the light reflecting means of the light control layer, and the liquid crystal display device can be effectively illuminated.

At this time, the difference in refractive index between the adhesive layer and the low refractive index layer is, for example, 0.05 or more, preferably 0.1 or more. The adhesive layer has a higher refractive index than that of the substrate, as in the case of the light control layer. For example, the difference is within 0.05. Moreover, it is preferable that the adhesive layer is formed of a pressure-sensitive adhesive because the degree of freedom in bonding is high.

The type of liquid crystal panel is not particularly limited. A TN liquid crystal panel, an STN liquid crystal panel, and a liquid crystal panel utilizing light diffusion are preferably used. In the case of a TN liquid crystal panel or an STN liquid crystal panel, one polarizing plate is provided on at least one side of the liquid crystal panel, and at least one birefringent film having birefringence is provided between the polarizing plate and the substrate of the liquid crystal panel. It is installed.

The type of substrate is not particularly limited. Since the transmitted light is transmitted through the substrate, one having high transparency is preferable. Therefore, a colorless and transparent material such as alkali-free glass is preferable. Also, from the viewpoint of weight reduction,
Plastic substrates are preferred. From the viewpoint of reducing the influence of birefringence and suppressing the loss of light, the substrate is preferably an optically isotropic member. It is preferable to use a transparent substrate having a certain thickness as the transparent substrate of the liquid crystal panel because the light emitted from the light source can be efficiently transmitted through the inside of the substrate.

In the case of the LCD of the present invention, since the light transmitted through the substrate of the liquid crystal panel is used, it is preferable that the substrate provided with the light source is thicker than the other substrates. This is because the incidence efficiency of light from the light source is high.
On the other hand, it is preferable that the other substrate not provided with the light source is thinner in consideration of the thickness and weight of the entire liquid crystal panel. In the liquid crystal panel, the upper substrate and the lower substrate may have the same thickness or different thicknesses.

Considering the efficiency of light incident on the substrate having the light source, the substrate having the light source preferably has a larger area than the other substrate not having the light source at the light incident end face. . In particular, when the light source is provided on one end surface of the substrate, for example, by providing a light source reflecting means such as a silver thin film deposited on an inelastic plastic film by closely arranging the lighting device around the upper substrate, Light from the illumination device can be effectively incident on the substrate, and bright illumination can be expected.

The polarizer and the polarizing plate of the present invention are not limited to the liquid crystal display device as described above, and examples thereof include an organic electroluminescence (EL) display, a plasma display (PD), an FED (field emission display: It can also be used for self-luminous display devices such as field emission displays.

An electroluminescence (EL) display device having the polarizing plate of the present invention will be described below.
The EL display device of the present invention is a display device having the polarizer or polarizing plate of the present invention, and the EL device may be either an organic EL or an inorganic EL.

In recent years, also in an EL display device, it has been proposed to use an optical film such as a polarizer or a polarizing plate together with a λ / 4 plate to prevent reflection from an electrode in a black state. The polarizer and the polarizing plate of the present invention, in particular,
When linearly polarized light, circularly polarized light, or elliptically polarized light is emitted from the EL layer, or even when natural light is emitted in the front direction, obliquely emitted light is partially polarized, etc. Very useful.

First, a general organic EL display device will be described. The organic EL display device generally has a light emitting body (organic EL light emitting body) in which a transparent electrode, an organic light emitting layer, and a metal electrode are laminated in this order on a transparent substrate. The organic light emitting layer is a laminate of various organic thin films, for example, a laminate of a hole injection layer containing a triphenylamine derivative or the like and a light emitting layer containing a fluorescent organic solid such as anthracene, or There are various combinations such as a laminate of a light emitting layer and an electron injection layer containing a perylene derivative, and a laminate of the hole injection layer, a light emitting layer and an electron injection layer.

Then, such an organic EL display device is
By applying a voltage to the anode and the cathode, holes and electrons are injected into the organic light emitting layer, and the energy generated by the recombination of the holes and electrons excites and excites the fluorescent substance. The fluorescent substance emits light when it returns to the ground state. The mechanism of the recombination of holes and electrons is the same as that of a general diode, and the current and the emission intensity show a strong non-linearity with rectification with respect to the applied voltage.

In the organic EL display device, at least one of the electrodes needs to be transparent in order to extract light emitted from the organic light emitting layer. Therefore, a transparent conductor such as indium tin oxide (ITO) is usually used. The transparent electrode formed in 1) is used as an anode. On the other hand, in order to facilitate electron injection and increase luminous efficiency, it is important to use a substance having a small work function for the cathode. Usually, Mg-Ag or Al is used.
-A metal electrode such as Li is used.

In the organic EL display device having such a structure, it is preferable that the organic light emitting layer is formed of an extremely thin film having a thickness of, for example, about 10 nm. This is because light is almost completely transmitted through the organic light emitting layer as well as the transparent electrode. As a result, at the time of non-light emission, the light that enters from the surface of the transparent substrate, passes through the transparent electrode and the organic light emitting layer, and is reflected by the metal electrode again exits to the surface side of the transparent substrate. Therefore, when viewed from the outside, the display surface of the organic EL display device looks like a mirror surface.

The organic EL display device of the present invention includes, for example, an organic EL display device including a transparent electrode on the surface of the organic light emitting layer and a metal electrode on the back surface side of the organic light emitting layer. In the above, the polarizer or the polarizing plate of the present invention is preferably arranged on the surface of the transparent electrode, and further, a λ / 4 plate is preferably arranged between the polarizing plate and the EL element. As described above, by disposing the polarizer or the polarizing plate of the present invention, the organic EL display device exhibits the effect of suppressing the reflection of external light and improving the visibility. Further, it is preferable that a retardation plate is further arranged between the transparent electrode and the optical film.

The retardation plate, the polarizer and the like are, for example,
Since it has a function of polarizing the light incident from the outside and reflected by the metal electrode, there is an effect that the mirror effect of the metal electrode is not visually recognized from the outside by the polarization action.
In particular, a quarter wave plate is used as the retardation plate, and the angle formed by the polarization directions of the polarizing plate and the retardation plate is π / 4.
The mirror surface of the metal electrode can be completely shielded by adjusting. That is, of the external light that enters the organic EL display device, only the linearly polarized light component is transmitted by the polarizer. This linearly polarized light is generally elliptically polarized light by the retardation plate, and in particular, when the retardation plate is a quarter wavelength plate and the angle is π / 4, it becomes circularly polarized light.

This circularly polarized light is transmitted through, for example, the transparent substrate, the transparent electrode, and the organic thin film, is reflected by the metal electrode, is transmitted again through the organic thin film, the transparent electrode, and the transparent substrate, and is again transmitted by the retardation plate. It becomes linearly polarized light. Since this linearly polarized light is orthogonal to the polarization direction of the polarizing plate, it cannot pass through the polarizing plate, and as a result, the mirror surface of the metal electrode can be completely shielded as described above. .

[0142]

The present invention will be described below with reference to examples.
The present invention is not limited to these examples.

Example 1 A polyvinyl alcohol film having a thickness of 80 μm was immersed in a 0.3 wt / v% iodine aqueous solution to give 3 parts.
It was immersed at 0 ° C. for 1 minute. Then, it is stretched to three times its original length, and then immersed in an aqueous solution (6 liters) containing 4 wt / v% boric acid and 0.5 wt / v% potassium iodide at 60 ° C. for 2 minutes, It was stretched up to 5.5 times its original length. Then, soak in pure water at 30 ° C for 10 seconds to wash,
A polarizing plate was obtained by drying at 50 ° C. for 4 minutes.

Example 2 A polyvinyl alcohol film having a thickness of 80 μm was immersed in a 0.3 wt / v% iodine aqueous solution to give 3 parts.
It was immersed at 0 ° C. for 1 minute. Then, it was stretched to 3 times its original length and then stretched to 5.5 times its original length while being immersed in a 4 wt / v% boric acid aqueous solution at 60 ° C. for 2 minutes. Then, soak in pure water at 30 ° C for 10 seconds to wash,
A polarizing plate was obtained by drying at 50 ° C. for 4 minutes.

Example 3 A polyvinyl alcohol film having a thickness of 80 μm was immersed in a 0.3 wt / v% iodine aqueous solution to give 3 parts.
It was immersed at 0 ° C. for 1 minute. Then, it was stretched to 3 times its original length and then immersed in an aqueous solution (6 liters) containing 4 wt / v% boric acid and 0.8 wt / v% potassium iodide at 60 ° C. for 2 minutes, It was stretched up to 5.5 times its original length. Then, soak in pure water at 30 ° C for 10 seconds to wash,
A polarizing plate was obtained by drying at 50 ° C. for 4 minutes.

Example 4 A polyvinyl alcohol film having a thickness of 80 μm was immersed in a 0.3 wt / v% iodine aqueous solution to give 3 parts.
It was immersed at 0 ° C. for 1 minute. Then, it was stretched to 3 times its original length, and then immersed in an aqueous solution (6 liters) containing 4 wt / v% boric acid and 1.3 wt / v% potassium iodide at 60 ° C. for 2 minutes, It was stretched up to 5.5 times its original length. Then, soak in pure water at 30 ° C for 10 seconds to wash,
A polarizing plate was obtained by drying at 50 ° C. for 4 minutes.

Comparative Example 1 A polyvinyl alcohol film having a thickness of 80 μm was immersed in a 0.3 wt / v% iodine aqueous solution at 30 ° C. for 1 minute. Then, it was stretched to 3 times its original length and then immersed in an aqueous solution (6 liters) containing 4 wt / v% boric acid and 5 wt / v% potassium iodide at 60 ° C. for 2 minutes, It was stretched to 5.5 times its length. After that, it is immersed in pure water at 30 ° C for 10 seconds for cleaning, and then at 50 ° C.
It was dried for 4 minutes to obtain a polarizing plate.

(Comparative Example 2) A polyvinyl alcohol film having a thickness of 80 μm was immersed in a 0.3 wt / v% iodine aqueous solution to give 3 parts.
It was immersed at 0 ° C. for 1 minute. Then, it was stretched to 3 times its original length and then stretched to 5.5 times its original length while being immersed in a 4 wt / v% boric acid aqueous solution at 60 ° C. for 2 minutes. Then, add 1% aqueous solution of 2% potassium iodide at 30 ° C.
It was dipped for 0 seconds to be washed, and dried at 50 ° C. for 4 minutes to obtain a polarizing plate.

(Evaluation) Examples 1 to 4 and Comparative Examples 1 and 2
Using a spectrophotometer (manufactured by Murakami Color Research Laboratory, trade name: Dot-3C), the polarizing plate prepared in 1.
The parallel transmittance and the orthogonal transmittance at a wavelength of 00 nm were measured. Table 1 shows the luminosity-corrected single transmittance, polarization degree, and a value and b value of Hunter Lab color system. JI
According to SK 7105 5.3, the tristimulus values (X, Y, Z) of the sample are measured using a spectrophotometer or a photoelectric colorimeter, and these values are shown as the color difference formula in Lab space below in the Hunte
By substituting into the equation of r, simplex, parallel and orthogonal a and b values were calculated.

Single a value = 17.5 (1.02X _S -Y _S ) / Y _S ^1/2 Single b value = 7.0 (Y _S -0.847Z _S ) / Y _S ^1/2 Parallel a value = 17.5 (1.02X _P -Y _P ) / Y _P ^1/2 parallel b value = 7.0 (Y _P -0.847Z _P ) / Y _P ^1/2 orthogonal a value = 17.5 (1 .02X _C −Y _C ) / Y _C ^1/2 orthogonal b value = 7.0 (Y _C −0.847Z _C ) / Y _C ^1/2 [wherein, X _S , Y _S, and Z _S are simple substances X _P , Y _P and Z _P are parallel tristimulus values of X _C ,
Y _C and Z _C are orthogonal tristimulus values]

Further, the first main transmittance (k ₁ ) was obtained from the values of the parallel transmittance and the orthogonal transmittance using (Equation 1).

(Equation 1) k ₁ = 0.5 × √2 {[(H ₀ + H ₉₀ ) ^1/2 + (H ₀ −H ₉₀ ) ^1/2 ]} where H ₀ : parallel transmittance, H ₉₀ : Cross transmittance

5 to 8 show the first main transmittance (k ₁ ) spectra at wavelengths of 400 nm to 700 nm. Figure 5
Is Example 1 and Comparative Examples 1 and 2, and FIG. 6 is Example 2
Comparative Examples 1 and 2, FIG. 7 shows the spectra of the polarizing plates of Example 3 and Comparative Examples 1 and 2, and FIG. 8 shows the spectra of the polarizing plates of Example 4 and Comparative Examples 1 and 2. From Figures 5-8, 40
The difference between the maximum value and the minimum value of the first main transmittance in the wavelength range of 0 nm to 700 nm is 4.1% in Example 1, 4.3% in Example 2, 6.0% in Example 3, and Example. In 4 is 7.
7%, 12.2% in Comparative Example 1, 15.2 in Comparative Example 2
%Met. Further, from FIGS. 5 to 8, 400 nm to 700
The minimum value of the first main transmittance at the wavelength of nm is as shown in Example 1.
86.5% in Example 2, 86.1% in Example 2, 84.2% in Example 3, 82.9% in Example 4, 78.6% in Comparative Example 1, and 74.6% in Comparative Example 2. Met.

Example 5 Thickness 0.7 mm, refractive index 1.
On the non-alkali glass plate 52, magnesium fluoride was formed as a low refractive index layer by vacuum vapor deposition. Using this as an upper transparent substrate, an ITO film was sputtered to form a transparent electrode. The refractive index of the low refractive index layer is 1.3
8. The thickness was 600 nm.

Similarly, the thickness of the lower substrate is 0.7
A UV-curable resin was applied to a non-alkali glass plate having a thickness of 1.5 mm and a refractive index of 1.52, and a film roughened in advance was pasted thereon. The surface of the alkali-free glass plate was roughened by irradiating it with a metal halide lamp to cure the UV-curable resin and peeling the previously roughened film from the cured resin. Aluminum was vapor-deposited thereon to form a reflective electrode.

A pair of the above substrates were used, and a 10 wt / v% aqueous solution of polyvinyl alcohol was applied by spin coating to the electrode-side surface of the substrate and dried, and then a rubbing treatment was performed to form a rubbing film. The transparent electrode on the upper substrate is
It is divided by etching. After that, the transparent electrodes are opposed to the pair of the substrates so that the rubbing directions are orthogonal to each other, spacers are arranged, and the substrate and the periphery of the substrate are sealed with an epoxy resin, and then liquid crystal “ZLI-479” manufactured by Merck & Co., Inc.
2 ”was injected to prepare a TN type reflective liquid crystal cell. At this time, the upper substrate was installed so as to be longer than the lower substrate by 2 mm at one end portion to form a light incident end face. The polarizing plate prepared in Example 1 was attached to both sides thereof with pressure sensitivity to prepare a normally white reflective liquid crystal panel. The size of the obtained liquid crystal panel is 45 mm in width, 34 mm in length, and 1.
It was 6 mm.

A cold cathode tube was placed as a light source on one surface of this reflection type liquid crystal panel, and the light source was covered with a light source reflecting means in which silver was deposited on a polyethylene terephthalate (PET) film. However, it was covered except for the part in contact with one surface of the liquid crystal panel. The light source reflecting means was attached to the upper and lower surfaces of the upper substrate with double-sided tape to prevent light from leaking.

[0158] Make a U on a mold that has been previously processed into a predetermined shape.
80μ after dropping V-curable acrylic resin with a dropper
An m-thick triacetyl cellulose (TAC) film was allowed to stand still on this resin and adhered by a rubber roller, and excess resin and air bubbles were extruded. This laminate was irradiated with a metal halide lamp and cured. afterwards,
The film was peeled from the mold, cut into a predetermined size, and molded. Remove the TAC film from the film,
An optical film as a light control layer was obtained. The refractive index of the UV curable resin after curing was previously measured with an ellipsometer and found to be 1.51.

The obtained optical film has a width of 40 mm, a length of 30 mm and a thickness of 75 μm, and the light reflecting means is continuous in the width direction. Each light reflection means was formed parallel to the short side, and the light reflection means was formed at an angle of 21 ° with respect to the width direction. The light reflecting means has a pitch of 210 μm and is provided continuously with the adjacent light reflecting means having a triangular cross section composed of an inclined surface and a flat surface. The width of the inclined surface of the light reflecting means was 10 μm to 16 μm, the angle was 42 °, and the angle of the flat surface was in the range 1.8 ° to 3.5 °. Further, the angle change of the adjacent flat surfaces was within 0.1 °. The area of the flat surface was 12 times or more that of the slope.

A film-shaped acrylic pressure-sensitive adhesive was attached in advance to the surface of the optical film opposite to the surface on which the light reflecting means was formed, and degassed by heating in an autoclave, and the adhesive was applied to that surface. A light control layer having an adhesive layer was obtained by bringing them into close contact with each other. The refractive index of the pressure sensitive adhesive is 1.53. On the surface of the above reflective liquid crystal panel,
A reflective liquid crystal display device was manufactured by stacking a light control layer on the upper transparent substrate of the liquid crystal panel so that the adhesive layer faces each other.

Example 6 The polarizing plate prepared in Example 2 was used instead of the polarizing plate prepared in Example 1.
A liquid crystal display device was manufactured in the same manner as in Example 5.

Example 7 The polarizing plate prepared in Example 3 was used instead of the polarizing plate prepared in Example 1.
A liquid crystal display device was manufactured in the same manner as in Example 5.

Example 8 The polarizing plate prepared in Example 4 was used instead of the polarizing plate prepared in Example 1.
A liquid crystal display device was manufactured in the same manner as in Example 5.

Comparative Example 3 The polarizing plate prepared in Comparative Example 1 was used instead of the polarizing plate prepared in Example 1.
A liquid crystal display device was manufactured in the same manner as in Example 5.

Comparative Example 4 The polarizing plate prepared in Comparative Example 2 was used instead of the polarizing plate prepared in Example 1.
A liquid crystal display device was manufactured in the same manner as in Example 5.

The brightness in the front direction and the chromaticity according to the CIE1931 color system of the liquid crystal display devices produced in Examples 5 to 8 and Comparative Examples 3 to 4 were measured by using Minolta's spectral radiance meter CS-100.
It was measured using 0. At this time, no voltage is applied to the liquid crystal panel, and the entire screen is in white display. The measurement is 5mm, 15mm, 25m from the light source side of the liquid crystal panel.
m points. The results are shown in FIG.

[0167]

[Table 1]

From the comparison between Examples 5 to 8 and Comparative Examples 3 to 4, when using a polarizing plate in which the difference between the maximum value and the minimum value of the first main transmittance at a wavelength of 400 nm to 700 nm is within 10%. It was found that the change in the chromaticity diagram on the liquid crystal panel was small and the white change was small.

[0169]

As described above, when the polarizer or the polarizing plate of the present invention is used in an image display device such as a liquid crystal display device, it is possible to suppress coloring of transmitted light.

[Brief description of drawings]

FIG. 1 is a diagram showing an axial direction of a protective layer.

FIG. 2 is a schematic cross-sectional view showing one structural example of a reflective liquid crystal display device of the present invention.

FIG. 3 is a schematic cross-sectional view showing one structural example of a transflective liquid crystal display device of the present invention.

FIG. 4 is a schematic cross-sectional view showing one structural example of a transmissive liquid crystal display device of the present invention.

FIG. 5 is a first main transmittance spectrum diagram of polarizing plates of Example 1 and Comparative Examples 1 and 2 at a wavelength of 400 nm to 700 nm.

FIG. 6 is a first main transmittance spectrum diagram of polarizing plates of Example 2 and Comparative Examples 1 and 2 at a wavelength of 400 nm to 700 nm.

7 is a first main transmittance spectrum diagram of polarizing plates of Example 3 and Comparative Examples 1 and 2 at wavelengths of 400 nm to 700 nm. FIG.

FIG. 8 is a first main transmittance spectrum diagram of polarizing plates of Example 4 and Comparative Examples 1 and 2 at a wavelength of 400 nm to 700 nm.

FIG. 9 is a chromaticity diagram of the liquid crystal display devices of Examples 5 to 8 and Comparative Examples 3 to 4 according to the CIE1931 color system.

[Explanation of symbols]

10: Lower transparent substrate 10a: lower substrate 11: Reflective electrode 13: Semi-transmissive reflective electrode 17, 21: Transparent electrode 12, 22: Rubbing film 14, 24: Low refractive index layer 15, 25: Polarizing plate 16, 26: Phase difference plate 18, 28: Adhesive layer 20: upper transparent substrate 23: Color filter 30: Liquid crystal layer 31: Seal material 40: Light control layer 51: Light source 52: Light source reflection means 60: Reflective layer 100, 200, 300: Liquid crystal panel 101, 201, 301: Liquid crystal display device A: light reflecting means A1: Slope

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Takahisa Konishi             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. (72) Inventor Seiji Umemoto             1-2 1-2 Shimohozumi, Ibaraki City, Osaka Prefecture Nitto             Electric Works Co., Ltd. F-term (reference) 2H049 BA02 BA06 BA22 BA25 BB03                       BB22 BC03 BC22                 2H091 FA08X FA08Z FA11X FA11Z                       FB02 FC01 HA07 HA10 KA01                       KA10                 3K007 AB17 BB06 DB03

Claims (15)

[Claims] 1. A polarizer including a polymer film, wherein the difference between the maximum value and the minimum value of the first main transmittance at a wavelength of 400 nm to 700 nm is within 10%. 2. The polarizer according to claim 1, wherein the minimum value of the first main transmittance at a wavelength of 400 nm to 700 nm is 70% or more. 3. The polarizer according to claim 1, wherein the auxiliary illuminant C has a single transmittance of which the luminosity factor is corrected in a 2 ° visual field of 45% or more and a polarization degree of 95% or more. 4. The polarizer according to claim 1, wherein a parallel b value in the Hunter Lab system is −2 to 0.5. 5. A polarizing plate comprising the polarizer according to claim 1 and a transparent protective layer, wherein the transparent protective layer is laminated on at least one surface of the polarizer. . 6. A liquid crystal display device comprising a liquid crystal panel and the polarizer according to claim 1. 7. A light source for illuminating the inside of the liquid crystal display device, and a light control layer for reflecting the light emitted from the light source transmitting inside the liquid crystal panel, wherein the light source is provided on at least one side surface of the liquid crystal panel. The liquid crystal display device according to claim 6, wherein the light control layer is disposed on one surface of the liquid crystal panel, and the polarizer is disposed between the liquid crystal panel and the light control layer. 8. The liquid crystal display device according to claim 6, further comprising a retardation plate, wherein the retardation plate is located between the polarizer and the liquid crystal panel. 9. A liquid crystal display device including a liquid crystal panel and the polarizing plate according to claim 5. 10. A light source that further illuminates the inside of the liquid crystal display device, and a light control layer that reflects the light emitted from the light source that is transmitted inside the liquid crystal panel.
9. The liquid crystal panel according to claim 8, wherein the liquid crystal panel is disposed on at least one side surface, the light control layer is disposed on one surface of the liquid crystal panel, and the polarizing plate is disposed between the liquid crystal panel and the light control layer. The described liquid crystal display device. 11. The liquid crystal display device according to claim 9, further comprising a retardation plate, wherein the retardation plate is located between the polarizing plate and the liquid crystal panel. 12. At least one image display device selected from the group consisting of a liquid crystal display device, a plasma display device and an electroluminescence display device, comprising the polarizer according to any one of claims 1 to 4. An image display device characterized by. 13. At least one image display device selected from the group consisting of a liquid crystal display device, a plasma display device, and an electroluminescence display device, wherein the image comprises the polarizing plate according to claim 5. Display device. 14. A method for producing a polarizer, comprising immersing a polymer film in a solution of a dichroic dye for dyeing, immersing the film in a solution of boric acid, and stretching the film once or more. The method includes the steps of immersing the film in pure water to wash the film, and drying the film.
4. The method for producing a polarizer according to any one of 4 above. 15. The method according to claim 14, wherein the boric acid solution further contains 1.5 wt / v% or less of potassium iodide.