JPH11183723A - Composite polarizing plate, reflection preventive filter using the plate and touch panel with reflection preventing - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a highly massproductive composite polarizing plate having high reflection preventing performance in a wide wavelength range of the visual light region and is also capable of reducing the deterioration in reflection preventing performance in accordance with an observation angle. SOLUTION: The composite polarizing plate consists of laminating a polarizing film, a 1/2 wavelength plate and 1/4 wavelength plate in this order, the angle formed by the absorption axis of the film and the phase lagging axis on the surface of the film of the 1/2 wavelength plate is 10 to 20 deg., the angle formed by the phase lagging axis on the surface of the film of the 1/2 wavelength plate and the lagging axis of the 1/4 wavelength plate on the surface of the film is 55 to 65 deg., and the phase lagging axis of the 1/2 wavelength plate is between the absorption axis of the film and the phase lagging axis of the 1/4 wavelength plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a composite polarizing plate having a good antireflection function over a wide wavelength range of visible light and a good antireflection function over a wide viewing angle range.

[0002]

2. Description of the Related Art In a display device such as a CRT, there is a problem that the contrast is reduced due to the influence of external light reflected on the surface of the display device, and an unnecessary reflected image due to the external light is seen, making it difficult to determine the display. was there. By disposing a filter having an anti-reflection function on the surface of the display device, the influence of the external light is reduced. At present, as a filter having such an antireflection function, a filter in which a polarizing film and a circularly polarizing plate composed of a quarter-wave plate are laminated on one surface of a transparent polymer sheet is used.

[0003] The principle of the antireflection function of this circularly polarizing plate is based on the application of a polarizing film (published by CMC Corporation).
And a quarter-wave plate is attached to the polarizing film so that the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the quarter-wave plate is 45 degrees. The combination is shown. However, a normal quarter-wave plate shows a retardation value that is a quarter of the wavelength of light, that is, a phase difference of 90 degrees is shown only for a specific wavelength. It is a well-known fact that the antireflection performance decreases as the wavelength deviates from the specific wavelength. An ordinary quarter-wave plate is mainly manufactured by stretching a film made of polycarbonate (hereinafter referred to as PC) having excellent transparency and high uniformity of the retardation value. PC quarter-wave plate made to have a retardation value of about 138 nm, which is one-fourth the magnitude of light having a wavelength of 550 nm, ie, having a phase difference of about 90 degrees. 14 shows the wavelength dependence of the phase difference in the visible light region. As shown in FIG. 14, the phase difference with respect to the wavelength is 90 degrees only when the wavelength is about 550 nm. As the wavelength deviates from 550 nm, the phase difference with respect to each wavelength deviates from 90 degrees. As a result, in a wavelength region out of the wavelength of 550 nm, the antireflection performance decreases. Such a quarter-wave plate made of PC and a polarizing film bonded together with a polarizing film were attached to a mirror-finished aluminum plate, light was incident from a vertical direction, and the antireflection effect was measured by its reflection spectrum. FIG. 5 shows the results. A low reflectivity indicates that the antireflection performance is high, but the antireflection performance at about 550 nm is large, but as the wavelength deviates from 550 nm, the antireflection performance decreases significantly. In this measurement, the reflectance of the mirror-finished aluminum plate is set to 100%. Although the reflectance at a wavelength of about 550 nm is theoretically 0%, the reason why the reflectance is not 0% is due to the influence of reflection on the polarizing film surface and the like.

[0004] In order to improve the deterioration of the antireflection performance, the wavelength dependence of the phase difference is set to 90 degrees in the visible light region more than in the PC.
A retardation film obtained by stretching a polyvinyl alcohol (PVA) film or a norbornene-based (NB) polymer film is also being studied as a material that can approach the temperature. A NB-based polymer film having a retardation value of about 130 nm with respect to light having a wavelength of 550 nm was used.
FIG. 15 shows the wavelength dependence of the phase difference of the half-wave plate. P
The phase difference is 90 for each wavelength in the visible light region as compared with C.
It turns out that the degree is approaching. A quarter-wave plate using this NB-based polymer film and a circularly polarizing plate obtained by bonding a polarizing film to a mirror-finished aluminum plate were pasted, and light was incident from a vertical direction to measure the antireflection performance. FIG. 6 shows the results. As shown in FIG. 6, as in the case of using a quarter-wave plate made of PC, the antireflection performance at about 550 nm is large, but as the wavelength deviates from 550 nm, the antireflection performance decreases significantly. The antireflection performance has not been greatly improved.

[0005] In order to further improve this, a retardation film obtained by stretching an olefin-based polymer film and a retardation film made of PC are bonded together so that the slow axes in the film plane are orthogonal to each other. The phase difference is almost 90 degrees 4
A one-half retardation plate has also been developed, but it is difficult to obtain a uniform retardation film made of an olefin-based polymer, and when the viewing angle is shifted from the front direction, the antireflection effect is greatly reduced. There are problems such as seeing.

[Problems to be solved by the invention]

In view of this situation, the present inventors have bonded a polarizing film, a half-wave plate, and a quarter-wave plate in this order at a specific angle setting, so that a wide wavelength range of the visible light region can be obtained. Thus, a composite polarizing plate having not only excellent anti-reflection performance but also excellent reduction in anti-reflection performance depending on the viewing angle and excellent in mass productivity can be developed, and the present invention has been completed.

[0007]

That is, the present invention provides:
(1) A polarizing film, a half-wave plate and a quarter-wave plate are laminated in this order, and the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate are formed. Angle 1
0 ° to 20 °, and the angle between the slow axis in the film plane of the half-wave plate and the slow axis in the film plane of the quarter-wave plate is 55 ° to 65 °; A composite polarizing plate, wherein the slow axis of the quarter-wave plate is between the absorption axis of the polarizing film and the slow axis of the quarter-wave plate, (2) the polarizing film and the half wavelength The plate and the quarter-wave plate are laminated in this order, and the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate is 100 ° to 110 °, and 2 °. The angle between the slow axis in the film surface of the half-wave plate and the slow axis in the film surface of the long plate is 55 to 65 degrees, and the slow axis of the half-wave plate is A composite polarizing plate whose axis is between the absorption axis of the polarizing film and the slow axis of the quarter-wave plate; (3) antireflection using any one of the above composite polarizing plates Filter, to a (4) the one with antireflection function touch panel using a one composite polarizing plate.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The polarizing film used in the present invention is not particularly limited. An iodine-based polarizing film having high polarizing performance may be used when antireflection performance is important, and when durability is required. It is appropriately selected such as using a dye-based polarizing film.

The half-wave plate and the quarter-wave plate used in the present invention have a uniform retardation value and a uniform slow axis direction obtained by stretching a polymer film having excellent transparency. It is not particularly limited as long as it has a retardation film. Examples of the polymer material used include a cellulosic polymer, a PC polymer, a polyarylate polymer, a polyester polymer, an acrylic polymer, polysulfone, and polyethersulfone. The method for forming these polymer films is not particularly limited as long as a uniform film can be obtained.
A film formed by a solvent casting method is preferably used. As the stretching method of the obtained polymer film, a longitudinal uniaxial stretching method between rolls and a tenter transverse stretching method are preferably used. In the present invention, since a retardation film obtained by stretching a solvent cast film using PC made of bisphenol A, which is excellent in uniformity and mass productivity and can be manufactured at low cost, can be used, it is very industrially advantageous.

The composite polarizing plate of the present invention is obtained by laminating a polarizing film, a half-wave plate and a quarter-wave plate in this order. The relationship between the absorption axis of the polarizing film, the slow axis in the film plane of the half-wave plate, and the slow axis in the film plane of the quarter-wave plate is as shown in FIG. The angle between the slow axis in the film plane of the half-wave plate and the slow axis in the film plane of the half-wave plate and the film plane of the quarter-wave plate are 10 to 20 degrees. Wherein the angle between the slow axes is 55 to 65 degrees, and the slow axis of the half-wave plate is between the absorption axis of the polarizing film and the slow axis of the quarter-wave plate; Alternatively, the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate is 100 ° to 110 °, and the slow axis in the film plane of the half-wave plate and the quarter axis. The angle between the slow axis in the film plane of the one-wave plate is 55 degrees to 65 degrees, and the slow axis of the half-wave plate is equal to the absorption axis of the polarizing film and And it serves as a between the slow axis of the waveplate. The measuring direction of the angle may be clockwise or counterclockwise. With such a composite, not only a good antireflection effect can be obtained in a wide wavelength range of the visible light region, but also a reduction in the antireflection effect can be reduced depending on the viewing angle. In particular, the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate is 100 degrees to 110 degrees, and the slow axis in the film plane of the half-wave plate is 4 minutes. The angle between the slow axis in the film plane of the 1-wave plate is 55 degrees to 65 degrees, and the slow axis of the 1 / 2-wave plate is the absorption axis of the polarizing film and the slow axis of the 1 / 4-wave plate. The one between the axes is preferable because the deterioration of the antireflection performance is small depending on the viewing angle.

The present inventors have studied various bonding configurations using various PC retardation films and found that the composite polarizing plate having the above configuration has excellent antireflection performance. It was found. FIG. 3 illustrates the antireflection performance of the composite polarizing plate according to the present invention. As shown in FIG. 3, as compared with the antireflection performance of a circularly polarizing plate using a quarter-wave plate made of PC or a quarter-wave plate made of NB-based polymer, the anti-reflection performance is wider in the visible light region. It shows excellent antireflection performance.

The retardation value (R2 / 1) in the film plane of the half-wave plate and the retardation value (R4 / 1) in the film plane of the quarter-wave plate used in the present invention are as follows. Is R2 / 1 = 250 nm to 300 nm,
R1 / 4 = 120 nm to 155 nm. There is no particular limitation on the tilt angle dependence of the retardation value of the wave plate, but one having an Nz coefficient in the range of about 0.5 to 1.5 is used. The Nz coefficient is a value calculated by the following equation (2). Nz = (nx−nz) / (nx−ny) (2) [wherein, nx represents the in-plane refractive index in the plane of the retardation plate, and ny represents the in-phase advance of the retardation plate. A refractive index in the axial direction is indicated, and nz indicates a refractive index in the thickness direction. Here, nx, ny, and nz are the Senarmont method (Senarm
ont Method).

In order to examine this effect in more detail, the present inventors have performed optical calculations using a very general 4 × 4 Jones matrix. Ideal polarizing film, half-wave plate with R1 / 2 = 275 nm and R1 / 4
= 138 nm, the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate is 15 degrees, in the film plane of the half-wave plate. The calculated antireflection performance when a composite polarizing plate having an angle of 60 degrees between the slow axis of the film and the slow axis in the film plane of the quarter-wave plate is attached to an ideal reflector. This is shown in FIG. 10 (see Example 1). FIG. 3 shows the antireflection performance of the actual composite polarizing plate described in Example 1 having the same specifications.
It is. In addition, a P1 of R1 / 4 = 133 nm calculated similarly.
FIG. 11 shows the antireflection performance of a circularly polarizing plate obtained by bonding a C quarter-wave plate and a polarizing film (see Comparative Example 1).
These figures show that the composite polarizing plate of the present invention has excellent antireflection performance. The difference between FIG. 3 and FIG. 10 and the difference between FIG. 5 and FIG. 11 are considered to be due to the influence of the reflected light on the polarizing film surface and the precision of the delicate bonding angle in the actual composite polarizing plate. From these results, it can be seen from the calculation study that a composite anti-reflection plate having the same anti-reflection performance as that of FIG. 10 can obtain high anti-reflection performance as shown in FIG. According to this study, R2 / 1 of the half-wave plate and R1 / 4 of the quarter-wave plate are R2 / 1 = 250 nm-
It was found that not only 300 nm and R1 / 4 = 120 nm to 155 nm, but | R1 / 2 × 0.5−R1 / 4 | is preferably 10 nm or less. FIG. 16 shows a preferable range of the combination of the retardation values. In FIG. 16, the preferred range is the inside surrounded by practice.

When the composite polarizing plate of the present invention is used for antireflection, when a normal polarizing film is used as described above, reflected light cannot be completely eliminated due to the influence of reflection on the surface of the polarizing film. Preventing or making the reflected light less visible is more effective when used as an anti-reflection filter. For example, on the surface of the opposite side of the bonding surface with the half-wave plate of the polarizing film,
It is very effective to provide an antiglare hard coat layer having fine irregularities on the surface, or to provide an antireflection layer formed of a dielectric multilayer film on the hard coat layer.

Since the composite polarizing plate according to the present invention is excellent in antireflection performance, it is bonded to a transparent substrate such as a glass plate or an acrylic resin sheet to obtain a reflection excellent in antireflection performance used for a display device such as a CRT. A prevention filter can be obtained. In the case where the composite polarizing plate is bonded to the back surface (the display device side) of the transparent substrate so that the polarizing film becomes the bonding surface, as shown in FIG. It is preferable to provide an antireflection layer made of a multilayer film of a treatment or a dielectric. In addition, a composite polarizing plate was placed on the surface (viewing side) of the transparent substrate by a quarter.
In the case of laminating so that the wave plate becomes the laminating surface, it is preferable to provide an anti-glare treatment having irregularities on the surface or an antireflection layer made of a dielectric multilayer film on the front side of the polarizing film.

The composite polarizing plate of the present invention is also effective as an anti-reflection element for a touch panel arranged on the surface of a display device. The attachment to the touch panel may be carried out on either the front or back surface of the touch panel as in the case of the antireflection filter. A polarizing film is preferably provided on the front side of the touch panel to reduce reflection by the surface of the touch panel and the transparent electrodes inside the touch panel, and a composite polarizing plate is used to easily transmit the pressure of a pen or finger for writing to the touch panel. Is preferably attached to the back surface of the touch panel. In order to achieve both, as shown in FIG. 13, only the polarizing film of the composite polarizing plate is attached to the front side of the touch panel, and a half-wave plate and a quarter-wave plate are attached to the back side of the touch panel. It is more preferable to separate them and bond them.

In the present invention, a polarizing film and a half
The method of attaching the wave plate, the half wave plate and the quarter wave plate, the composite polarizer and the transparent substrate, or the composite polarizer and the touch panel is not particularly limited, but is optically isotropic and durable. A method using an adhesive having excellent properties is preferably used. As the pressure-sensitive adhesive, an acrylic pressure-sensitive adhesive excellent in transparency and durability is particularly preferably used. The thickness of the pressure-sensitive adhesive is usually used in the range of 10 μm to 50 μm.

[0018]

Industrial Applicability The composite polarizing plate of the present invention not only exhibits excellent antireflection performance, but also has excellent uniformity and mass productivity, and has an antireflection filter for a display device and a touch panel with an antireflection function. It is suitably used for reflection type liquid crystal display devices and the like.

[0019]

EXAMPLES The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples. The antireflection performance in the examples was evaluated by attaching a composite polarizing plate to a mirror-finished aluminum plate using an adhesive, irradiating light from a vertical direction, and measuring its reflection spectrum. In this measurement, the reflectance of the mirrored aluminum plate was set to 100%. (Measurement instrument: TFM-120AFT, manufactured by Oak Manufacturing Co., Ltd.) Also, regarding the change in the antireflection effect depending on the viewing angle,
Evaluation was made by visually observing a sample adhered to a mirror-finished aluminum plate using an adhesive.

Example 1 Polarizing film (trade name: Sumikaran SQ-1852AP)
0 Sumitomo Chemical Co., Ltd.) 1/2 wave plate (trade name: Sumikalite SEF-460275B7 Sumitomo Chemical Co., Ltd., Nz = 1.0) Quarter wave plate (trade name: Sumikalite SEF-) 460138B7 A film made of Sumitomo Chemical Co., Ltd., Nz = 1.0), wherein the angle between the polarizing film and the slow axis in the film plane of the half-wave plate is 15 degrees and the half-wave plate is used. The angle between the in-plane slow axis and the slow axis in the film plane of the quarter-wave plate is 60 degrees, and the slow axis of the half-wave plate is equal to the absorption axis of the polarizing film and the quarter axis. So that it is between the slow axes of the one-wavelength plate,
The composite polarizing plate according to the present invention was prepared by bonding together with an acrylic pressure-sensitive adhesive having a thickness of about 25 μm. 4 of this composite polarizing plate
The one-half wavelength plate side was attached to a mirror-finished aluminum plate using an acrylic adhesive having a thickness of about 25 μm. When observed visually, almost no reflected light was seen, the color appeared black, and excellent antireflection performance was exhibited. FIG. 3 shows the reflection spectrum. In addition, when viewed at an angle, the increase in reflected light was slight, and almost black was maintained.

Example 2 Polarizing film (trade name: Sumikaran SQ-1852AP)
0 Sumitomo Chemical Co., Ltd.) 1/2 wave plate (trade name: Sumikalite SEF-460275B7 Sumitomo Chemical Co., Ltd., Nz = 1.0) Quarter wave plate (trade name: Sumikalite SEF-) 460138B7 A film made of Sumitomo Chemical Co., Ltd., Nz = 1.0), wherein the angle between the polarizing film and the slow axis in the film plane of the half-wave plate is 105 degrees and the half-wave plate is used. The angle between the in-plane slow axis and the slow axis in the film plane of the quarter-wave plate is 60 degrees, and the slow axis of the half-wave plate is equal to the absorption axis of the polarizing film and the quarter axis. The composite polarizing plate according to the present invention was prepared by bonding together with an acrylic adhesive having a thickness of about 25 μm so as to be between the slow axes of the one-wavelength plate. The quarter-wave plate side of the composite polarizing plate was attached to a mirror-finished aluminum plate using an acrylic adhesive having a thickness of about 25 μm. When observed visually, almost no reflected light was seen, the color appeared black, and excellent antireflection performance was exhibited. FIG. 4 shows the reflection spectrum. In addition, the increase in reflected light when viewed at an angle was slightly larger than in Example 1 but small.

Comparative Example 1 Polarizing film (trade name: Sumikaran SQ-1852AP)
0 Sumitomo Chemical Co., Ltd.), quarter-wave plate (trade name: Sumikalite SEF-460138B7, Sumitomo Chemical Co., Ltd., Nz = 1.0), using a polarizing film and a quarter-wave plate film A circularly polarizing plate was prepared by bonding with an acrylic adhesive having a thickness of about 25 μm so that the angle between the in-plane slow axes was 45 °. The quarter-wave plate side of this circularly polarizing plate was attached to a mirror-finished aluminum plate using an acrylic adhesive having a thickness of about 25 μm. Upon visual observation, the reflected light was purple and had poor antireflection performance. FIG. 5 shows the reflection spectrum. When viewed at an angle, the discoloration was large.

Comparative Example 2 Polarizing film (trade name: Sumikaran SQ-1852AP)
0, using a quarter-wave plate (R1 / 4 = 130 nm) obtained by uniaxially stretching an NB-based film (trade name: Arton Film JSR Co., Ltd.) The thickness of about 25 μm is set so that the angle of the slow axis in the film plane of the half-wave plate is 45 degrees.
Then, a circularly polarizing plate was prepared by bonding together with an acrylic pressure-sensitive adhesive. The quarter-wave plate side of this circularly polarizing plate is approximately 25 μm thick.
Was adhered to a mirror-finished aluminum plate using an acrylic adhesive. Upon visual observation, the reflected light was purple and had poor antireflection performance. FIG. 6 shows the reflection spectrum. Also, when viewed at an angle, the discoloration was large as in a quarter-wave plate made of PC.

Comparative Example 3 Polarizing film (trade name: Sumikaran SQ-1852AP)
0 Sumitomo Chemical Co., Ltd.) 1/2 wave plate (trade name: Sumikalite SEF-460275B7 Sumitomo Chemical Co., Ltd., Nz = 1.0) Quarter wave plate (trade name: Sumikalite SEF-) 460138B7 A film made of Sumitomo Chemical Co., Ltd., Nz = 1.0), wherein the angle between the polarizing film and the slow axis in the film plane of the half-wave plate is 45 degrees and the half-wave plate is used. The angle between the in-plane slow axis and the slow axis in the film plane of the quarter-wave plate is 90 degrees, and the slow axis of the half-wave plate is equal to the absorption axis of the polarizing film and the quarter-wave plate. So that it is between the slow axes of the one-wavelength plate,
A composite polarizing plate was prepared by bonding together with an acrylic adhesive having a thickness of about 25 μm. The quarter-wave plate side of the composite polarizing plate was attached to a mirror-finished aluminum plate using an acrylic adhesive having a thickness of about 25 μm. Upon visual observation, the reflected light was purple and had poor antireflection performance. FIG. 7 shows the reflection spectrum. When viewed at an angle, the discoloration was larger and the antireflection performance was poorer than in Comparative Example 1 using one quarter-wave plate made of PC.

Example 3 Ideal polarizing film, half-wave plate (R1 / 2 = 26)
5 nm, the wavelength dependence of the retardation is equivalent to that of PC, and the measurement wavelength of R1 / 2 is 550 nm.)
Wave plate (R1 / 4 = 133 nm, wavelength dependence of retardation is equivalent to PC, and measurement wavelength of R1 / 4 is 550 nm
The angle between the polarizing film and the slow axis in the film plane of the half-wave plate is 105 degrees and the slow axis in the film plane of the half-wave plate is 4 minutes. The angle between the slow axes in the film plane of the one-wavelength plate is 60 degrees,
A configuration in which the slow axis of the half-wave plate is superposed so as to be between the absorption axis of the polarizing film and the slow axis of the quarter-wave plate, and this is further superimposed on an ideal reflector. Then, the characteristics of the composite polarizing plate according to the present invention were calculated. FIG. 8 shows the reflection spectrum of this composite polarizing plate. It can be seen that excellent antireflection performance can be exhibited in a wide wavelength range of the visible light region.

Comparative Example 4 Ideal polarizing film, half-wave plate (R1 / 2 = 26)
5 nm, the wavelength dependence of the retardation is equivalent to that of PC, and the measurement wavelength of R1 / 2 is 550 nm.)
Wave plate (R1 / 4 = 154 nm, the wavelength dependence of retardation is equivalent to PC, and the measurement wavelength of R1 / 4 is 550 nm
The angle between the polarizing film and the slow axis in the film plane of the half-wave plate is 105 degrees and the slow axis in the film plane of the half-wave plate is 4 minutes. The angle between the slow axes in the film plane of the one-wavelength plate is 60 degrees,
A configuration in which the slow axis of the half-wave plate is superposed so as to be between the absorption axis of the polarizing film and the slow axis of the quarter-wave plate, and this is further superimposed on an ideal reflector. Then, the characteristics of the composite polarizing plate were calculated. FIG. 9 shows the reflection spectrum of this composite polarizing plate. It can be seen that the antireflection performance is inferior to that of Example 3.

Example 4 After forming a hard coat layer on one side of an acrylic sheet, an anti-reflection layer composed of a multilayer film of an inorganic dielectric is formed on the hard coat layer. The composite polarizing plate obtained in Example 1 is bonded to the other surface of the acrylic sheet using an adhesive so that the polarizing film faces the acrylic sheet, thereby producing an antireflection filter having a configuration shown in FIG. . This anti-reflection filter has excellent anti-reflection function, CR
It can be used for T filters and the like.

Example 5 The polarizing film used in Example 1 is attached to the front surface of the touch panel, and the half-wave plate and the quarter-wave plate used in Example 1 are attached to the back surface of the touch panel. At this time, the order of the polarizing film, the half-wave plate, and the quarter-wave plate and the angle at which they are attached are the same as those in the first embodiment, so that a touch panel with an antireflection function shown in FIG. 13 is created. . This touch panel can be used as a touch panel excellent in anti-reflection performance without any problem with input by a pen or a finger.

[0029]

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a composite polarizing plate according to the present invention.

FIG. 2 is a diagram exemplifying a relationship between angles of a composite polarizing plate in the present invention.

FIG. 3 is a reflection spectrum showing the antireflection performance of the composite polarizing plate according to the present invention of Example 1.

FIG. 4 is a reflection spectrum showing the antireflection performance of the composite polarizing plate according to the present invention of Example 2.

FIG. 5 is a reflection spectrum showing the antireflection performance of the circularly polarizing plate of Comparative Example 1.

FIG. 6 is a reflection spectrum showing the antireflection performance of the circularly polarizing plate of Comparative Example 2.

FIG. 7 is a reflection spectrum showing the antireflection performance of the composite polarizing plate of Comparative Example 3.

FIG. 8 is a reflection spectrum showing antireflection performance obtained by calculation of the composite polarizing plate according to the present invention of Example 3.

FIG. 9 is a reflection spectrum showing antireflection performance obtained by calculation of the composite polarizing plate of Comparative Example 3.

FIG. 10 is a reflection spectrum showing antireflection performance obtained by calculation of a composite polarizing plate according to the specifications of Example 1.

11 is a reflection spectrum showing antireflection performance obtained by calculation of a circularly polarizing plate according to the specifications of Comparative Example 1. FIG.

FIG. 12 is a configuration diagram of an antireflection filter according to a fourth embodiment of the present invention.

FIG. 13 is a configuration diagram of a touch panel with an antireflection function according to a fourth embodiment of the present invention.

FIG. 14 is a spectrum showing the wavelength dependence of the phase difference of a quarter-wave plate made of PC.

FIG. 15 is a spectrum showing the wavelength dependence of the phase difference of a quarter-wave plate made of an NB-based polymer.

FIG. 16 shows a preferred range of combinations of retardation values of R 2/1 of the half-wave plate and R 1/4 of the quarter-wave plate.

[Explanation of symbols]

1: polarizing film 2: half-wave plate 3: quarter-wave plate 4: adhesive 5: absorption axis direction of the polarizing film 6: slow axis direction in the film plane of the half-wave plate 7 : Slow axis direction in the film plane of the quarter-wave plate 8: Angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate 9: Half-wave plate Angle formed between the slow axis direction in the film surface and the slow axis direction of the film surface of the quarter-wave plate 10: Acrylic sheet 11: Hard coat layer and antireflection layer

Claims (9)

[Claims] 1. A polarizing film, a half-wave plate and a quarter
The wave plate is laminated in this order, the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half wave plate is 10 degrees to 20 degrees, and the half wave plate is The angle between the slow axis in the film plane and the slow axis in the film plane of the quarter-wave plate is 55 to 65 degrees, and the slow axis of the half-wave plate is the absorption axis of the polarizing film. And the slow axis of the quarter-wave plate. 2. A polarizing film, a half-wave plate and a quarter.
Wave plates are laminated in this order, and the angle between the absorption axis of the polarizing film and the slow axis in the film plane of the half-wave plate is 100 degrees to 110 degrees, and the half-wave plate is The angle formed by the slow axis in the film plane of the long plate is 55 to 65 degrees, and the slow axis of the half-wave plate is the absorption of the polarizing film. A composite polarizing plate characterized by being between the axis and the slow axis of the quarter-wave plate. 3. The retardation value (R1 / 2) in the film plane of the half-wave plate is 250 nm to 300 nm, and the retardation value (R1 / 4) in the film plane of the quarter-wave plate. ) Is from 120 to 155 nm, and R1
3. The composite polarizing plate according to claim 1, wherein / 2 and R1 / 4 satisfy the relationship of the formula (1). | R1 / 2 × 0.5-R1 / 4 | ≦ 10 (1) 4. The composite polarizing plate according to claim 1, wherein the half-wave plate and the quarter-wave plate are made of a retardation film made of polycarbonate. 5. The composite polarizing plate according to claim 1, wherein an antiglare hard coat layer having fine irregularities is provided on the surface of the polarizing film. 6. The composite according to claim 1, wherein a hard coat layer is provided on the surface of the polarizing film, and an anti-reflection layer formed of a dielectric multilayer film is provided on the surface. Polarizer. 7. An anti-reflection filter comprising the composite polarizing plate according to claim 1 laminated on a transparent substrate. 8. A touch panel with an antireflection function, wherein the composite polarizing plate according to claim 1 is laminated on the touch panel. 9. In laminating the composite polarizing plate according to claim 1 or 2 on a touch panel, a polarizing film is laminated on the viewing side of the touch panel, and a half-wave plate and a quarter-wave plate are laminated. 9. The touch panel with an antireflection function according to claim 8, wherein a film is laminated on the display body side of the touch panel.