JP2016173589A - Polarizer with adhesive, liquid crystal panel, and adhesive - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a polarizer with an adhesive in which light leakage is improved.SOLUTION: An aspect of the invention is a polarizer with an adhesive which is designed so as to improve light leakage by making distribution of absorption axes after a durability test on the polarizer with the adhesive stuck on a glass substrate small. Another aspect of the invention is a polarizer with an adhesive which is designed so as to improve light leakage by setting distribution of absorption axes after a heat resistance test at 80°C for seven days on the polarizer with the adhesive stuck on a glass substrate to the value of three times a standard deviation and 1.3 degree or less. Further another aspect of the invention is a polarizer with an adhesive which is designed so as to improve light leakage by setting difference between a maximum value and a minimum value of absorption axes after the heat resistance test at 80°C for seven days on the polarizer with the adhesive stuck on a glass substrate to 1.5 degree or less.SELECTED DRAWING: Figure 10

Description

  The present invention relates to a polarizing plate with an adhesive, which is a member of a liquid crystal display.

  Due to their excellent characteristics, liquid crystal displays are widely used as displays for mobile devices such as liquid crystal televisions, desktop personal computer monitors, laptop computers, and mobile phones. In recent years, especially the spread and development of liquid crystal televisions are remarkable, and many large-sized liquid crystal televisions exceeding 40 inches are sold.

  These liquid crystal televisions use transmissive liquid crystal panels, and usually two polarizing plates are bonded to the front and back of the liquid crystal panel. And it has the structure which illuminates these with a backlight from the back side.

  A general polarizing plate is produced by highly stretching a film mainly composed of polyvinyl alcohol containing iodine (Poly Vinyl Alcohol, PVA), orienting the molecules, and sandwiching them with a polarizing plate protective film. Furthermore, as shown in FIG. 33 to be described later, in the configuration using the retardation film, the polarizing plate protective film on the side adjacent to the retardation film is omitted and the retardation film serves as a polarizing plate protective film. There may be. These films have a structure in which they are bonded to each other with an adhesive, and these films are further bonded to a glass substrate with an adhesive.

  Here, it is known that the film mainly containing highly oriented polyvinyl alcohol and containing iodine, which is used in the central portion of the polarizing plate, gradually shrinks during use of the liquid crystal display. A polarizing plate (here, in the case of a configuration using a retardation film, this is referred to as a polarizing plate) is bonded to the glass substrate as described above.

  On the other hand, since the glass substrate hardly shrinks even during use of the liquid crystal display, it is considered that stress is generated in the polarizing plate and the pressure-sensitive adhesive that bonds the polarizing plate.

Due to these stresses, birefringence occurs in the polarizing plate and the adhesive, and the polarization state of the polarized light from the passing backlight is disturbed. As a result, for example, as shown in FIG. 11, light leaks during black display, the place where black should be displayed is displayed from gray to white, the contrast is significantly reduced, and if the degree is large, the image cannot be displayed correctly. Is a serious problem. This phenomenon is referred to as “light leakage” in this specification, and the occurrence of unevenness in the screen as a result of light leakage is referred to as “unevenness phenomenon”.
In general, the uneven phenomenon becomes prominent in a larger liquid crystal display. Therefore, there is a strong demand for improving the uneven phenomenon, particularly in large liquid crystal televisions.

In order to improve the uneven phenomenon, some attempts have been made to improve the polarizing plate and the pressure-sensitive adhesive. However, even if each of the polarizing plate and the adhesive is improved, there are many problems and the light leakage is not improved.
The cause of light leakage of the polarizing plate is that the polarizing plate is fixed to the liquid crystal panel (glass) with an adhesive against the expansion and contraction of the polarizing plate after the durability test. For this reason, it has been considered that birefringence (phase difference) occurs in the cellulose triacetate film (Tri Acetyl Cellulose, TAC), which is a protective film for the polarizer, at that portion. This is shown in FIG.

R = E × F × d
R: Phase difference generated in TAC
E: Photoelastic coefficient of TAC
F: Stress applied to TAC d: Thickness of TAC
(Non-Patent Document 1)

As a method for improving this, the following methods have been studied.

(1) Birefringence occurs by reducing the stress (F) applied to the TAC by softening the pressure sensitive adhesive and allowing the pressure sensitive adhesive to follow the shrinkage of the polarizing plate (increasing the amount of pressure sensitive adhesive). To improve light leakage.
F = δ × (polarization amount of polarizing plate−elongation amount of adhesive)
δ: Elastic modulus of TAC film (Patent Document 1)

(2) The TAC film is stressed by increasing the elastic modulus of the adhesive by the reverse method, and fixing the polarizing plate to the panel with the adhesive so that it does not deform in the durability test. However, since the area is small, methods for improving light leakage inconspicuously have been proposed (Non-patent Document 1, Patent Document 2).

In the past, by changing the composition and blending method of the pressure-sensitive adhesive by trial and error in accordance with the above-mentioned idea, a viscoelasticity of the pressure-sensitive adhesive was changed to produce a polarizing plate with a pressure-sensitive adhesive on the liquid crystal panel. It has been developed by sticking together and evaluating light leakage.

However, since the evaluation of light leakage is sensual and the mechanism of light leakage is unknown, it has taken time to develop a polarizing plate with an adhesive. It was also very difficult to balance light leakage with other performance. In fact, I could not know how much stress was applied to the TAC film and in what direction birefringence occurred. Furthermore, even when the type and size of the polarizing plate changed, it was necessary to redo the development of the polarizing plate with an adhesive from the beginning.

JP 10-279907 A JP 2006-235568

Bonding 2006 Volume 50 No.2 13 (61) SID 08 DIGEST 1457

This invention is made | formed in view of the above-mentioned background art, and aims at providing the polarizing plate with an adhesive etc. in which the light leakage was improved.

According to this invention, in order to achieve the above-mentioned object, the configuration as described in the claims is adopted. Hereinafter, the present invention will be described in detail.

The first aspect of the present invention is
The pressure-sensitive adhesive polarizing plate is designed to improve light leakage by reducing the distribution of the absorption axis after the durability test of the pressure-sensitive adhesive polarizing plate bonded to the glass substrate.

The second aspect of the present invention is
To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with the adhesive bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. It is in the designed polarizing plate with adhesive.

The third aspect of the present invention is
Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. It is in the polarizing plate with an adhesive.

The fourth aspect of the present invention is
4. The pressure-sensitive adhesive polarizing plate according to claim 1, wherein the pressure-sensitive adhesive has a gel content of 0.1% to 40%.

The fifth aspect of the present invention provides
4. The pressure-sensitive adhesive polarizing plate according to claim 1, wherein the pressure-sensitive adhesive has a gel content of 80% or more and 99% or less.

The sixth aspect of the present invention provides
6. The polarizing plate with an adhesive according to claim 1, wherein the polarizing plate is a polarizing plate for WV.

The seventh aspect of the present invention provides
The pressure-sensitive adhesive polarizing plate according to any one of claims 1 to 6, wherein the distribution of the degree of polarization after a heat resistance test at 80 ° C for 7 days after being attached to a glass substrate is not more than 0.2 in terms of three times the standard deviation. is there.

The eighth aspect of the present invention is
To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. It is in the designed polarizing plate with adhesive.

The ninth aspect of the present invention provides
9. The polarizing plate with an adhesive according to claim 8, wherein the distribution of the degree of polarization after being bonded to a glass substrate and subjected to a heat test at 80 ° C. for 7 days is 0.2 or less in terms of a triple value of the standard deviation.

The tenth aspect of the present invention provides
10. The pressure-sensitive adhesive polarizing plate according to claim 8, wherein an absolute value of the pressure-sensitive adhesive's intrinsic birefringence value is 4 × 10 ⁻⁴ or less.

The eleventh aspect of the present invention is
11. The pressure-sensitive adhesive according to claim 8, which is cut so that the absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate. It is in the polarizing plate.

The twelfth aspect of the present invention is
12. The polarizing plate with an adhesive according to claim 8, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS.

The thirteenth aspect of the present invention is
It exists in the design method of the polarizing plate with an adhesive which designs so that light leakage may be improved by reducing the distribution of the absorption axis after the durability test of the polarizing plate with an adhesive bonded on the glass substrate.

The fourteenth aspect of the present invention provides
To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with the adhesive bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. It is in the design method of the polarizing plate with an adhesive to design.

The fifteenth aspect of the present invention is
Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. It is in the design method of the polarizing plate with an adhesive.

The sixteenth aspect of the present invention is
16. The method for designing a polarizing plate with an adhesive according to any one of claims 13 to 15, wherein the gel content of the adhesive is 0.1% or more and 40% or less.

The seventeenth aspect of the present invention is
16. The method for designing a polarizing plate with an adhesive according to claim 13, wherein the gel content of the adhesive is 80% or more and 99% or less.

The eighteenth aspect of the present invention provides
18. The method for designing a polarizing plate with an adhesive according to claim 13, wherein the polarizing plate is a polarizing plate for WV.

The nineteenth aspect of the present invention provides
The pressure-sensitive adhesive polarizing plate according to any one of claims 13 to 18, wherein the polarization degree distribution after a heat resistance test at 80 ° C for 7 days after being attached to a glass substrate is not more than 0.2 in terms of a triple value of the standard deviation. It is in the design method.

The twentieth aspect of the present invention provides
To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. It is in the design method of the polarizing plate with an adhesive to design.

The 21st aspect of the present invention is
21. The method of designing a polarizing plate with an adhesive according to claim 20, wherein the distribution of the degree of polarization after being bonded to a glass substrate and subjected to a heat test at 80 ° C. for 7 days is 0.2 or less in terms of a triple value of the standard deviation.

The twenty-second aspect of the present invention provides
22. The method for designing a polarizing plate with an adhesive according to claim 20 or 21, wherein the absolute value of the inherent birefringence value of the adhesive is 4 × 10 ⁻⁴ or less.

The twenty-third aspect of the present invention provides
23. The pressure-sensitive adhesive according to any one of claims 20 to 22, which is cut so that an absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate. It exists in the design method of a polarizing plate.

The twenty-fourth aspect of the present invention provides
24. The method for designing a polarizing plate with an adhesive according to claim 20, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS.

The 25th aspect of the present invention is
It exists in the design method of the polarizing plate with an adhesive which designs so that the distribution of the absorption axis of an polarizing plate with an adhesive may be made small.

The twenty-sixth aspect of the present invention provides
26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the gel content of the adhesive is adjusted.

The twenty-seventh aspect of the present invention provides
26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the position of light leakage is specified from the distribution of axial deviation.

The 28th aspect of the present invention provides
26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the polarizing plate with an adhesive is a polarizing plate with an adhesive retardation layer.

The 29th aspect of the present invention provides
The polarizing plate with a retardation layer is formed by coating a retardation layer by coating a liquid crystal material on a transparent protective film, or by separately forming a retardation layer formed by coating a liquid crystal material on the transparent protective film. 29. The method for designing a polarizing plate with an adhesive retardation layer according to claim 28, wherein the polarizing plate is provided by transfer and the transparent protective film and the retardation layer are integrated.

The thirtieth aspect of the present invention is
30. The method for designing a polarizing plate with an adhesive retardation layer according to claim 29, wherein the retardation layer has a tilted alignment layer of a discotic liquid crystal fixed thereto.

The thirty-first aspect of the present invention provides
A liquid crystal panel manufacturing method using the pressure-sensitive adhesive plate designed by the method for designing a pressure-sensitive adhesive plate according to any one of claims 13 to 30.

The thirty-second aspect of the present invention provides
A deflection plate manufacturing method using the pressure-sensitive adhesive plate designed by the pressure-sensitive adhesive plate designing method according to any one of claims 13 to 30.

The thirty-third aspect of the present invention provides
It exists in the manufacturing method of the polarizing plate with an adhesive which suppresses light leakage by making the distribution of the axial shift of the absorption axis of a polarizing plate with an adhesive small.

According to the present invention, an adhesive-attached polarizing plate with improved light leakage can be obtained.

Other objects, features, or advantages of the present invention will become apparent from the detailed description based on the embodiments of the present invention described later and the accompanying drawings.

It is a figure which shows the shrinkage | contraction of a polarizing plate and the stress to TAC. It is a figure which shows the simulation of the shift | offset | difference of the absorption axis by the shrinkage | contraction of a WV (wide view) polarizing plate. It is a figure which shows the measuring method of an absorption axis and a polarization degree. It is a figure which shows the change of the polarization degree when the distribution of the absorption axis by the shrinkage | contraction of a polarizing plate and the angle of an axis | shaft are changed. It is a figure which shows the relationship between an absorption axis and the transmittance | permeability. It is a figure which shows the relationship between an absorption axis and the transmittance | permeability. It is a figure which shows the shift | offset | difference of the absorption axis in the front and back of a WV polarizing plate. It is a figure about WV polarizing plate (initial stage and polarizing plate free) It is a figure which shows the axial shift distribution of Example 4. FIG. It is a figure which shows the axial shift distribution of the comparative example 5. It is a figure which shows the light leak photograph of a WV polarizing plate. It is a figure which shows absorption axis (theta) p and orthogonal transmittance | permeability Yc. It is a figure which shows absorption axis (theta) p and orthogonal transmittance | permeability Yc. It is a figure which shows distribution of an absorption axis and a polarization degree. It is a figure which shows distribution of an absorption axis and a polarization degree. It is a figure which shows absorption axis distribution and orthogonal transmittance | permeability. It is a figure which shows absorption axis distribution and light leakage. It is a figure which shows transmission axis distribution and orthogonal transmittance | permeability. It is a figure which shows a light leak and an absorption axis. It is a figure which shows absorption axis distribution and polarization degree distribution. It is a figure which shows light leakage and a polarization degree. It is a figure which shows the shrinkage | contraction (observation from the top) of a polarizing plate. It is a figure which shows the contraction sectional drawing of a polarizing plate. It is a figure which shows absorption axis distribution and shrinkage | contraction rate. It is a figure which shows a gel part and shrinkage | contraction rate. It is a figure which shows an absorption axis and a visibility correction | amendment orthogonal transmittance | permeability. It is a figure which shows an absorption axis and visibility correction | amendment orthogonal transmittance | permeability (TN deflection plate 80 degreeC 7 days). It is a figure which shows the absorption axis and polarization degree of the deflection plate for VA. It is a figure which shows the absorption axis of VA deflection | deviation plate, and distribution of a polarization degree. It is a figure which shows the measuring method in a birefringence measuring apparatus. It is a figure which shows a polarizing plate measurement point. It is a figure which shows the measurement of the birefringence of an adhesive. It is a figure which shows the change of the absorption axis by a load. It is a figure which shows tension | tensile_strength of a polarizing plate. It is a figure which shows the cross-sectional example of a liquid crystal display. It is a figure which shows the shrinkage stress and light leakage of a polarizing plate. It is a figure which shows a light leak photograph and axial deviation distribution. It is a figure which shows a light leak photograph and axial deviation distribution. It is a figure which shows the measurement because the axial deviation of the absorption axis of the polarizing plate for WV is seen from the front and back. It is a figure which shows the axial shift of the absorption axis of the polarizing plate for TN, for VA.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

 [Overview]

This embodiment effectively suppresses “light leakage” that greatly impairs the display characteristics such as contrast of the liquid crystal display by reducing the distribution of the axis misalignment of the absorption axis of the adhesive polarizing plate bonded to the liquid crystal display. The present invention relates to a method for designing and manufacturing a polarizing plate with a pressure-sensitive adhesive, and a polarizing plate with a pressure-sensitive adhesive manufactured by the manufacturing method, a liquid crystal display device, a method for manufacturing these, and the like.

This time, through the efforts of the present inventors, the polarizing plate with adhesive and the polarizing plate with poor light leakage after being attached to the liquid crystal panel and subjected to the durability test are in the plane of the polarizing plate. It was found that there was a difference in the distribution of absorption axes depending on the location. It was also found that the polarizing plate before the durability test had no light leakage and the distribution of the absorption axis was very small.

It has also been found that light leakage can be improved by designing the pressure-sensitive adhesive so as to reduce the distribution of the absorption axis.

It was found that there are two ways to reduce the distribution of the absorption axis.

The first method is to increase the fluidity of the pressure-sensitive adhesive by reducing the gel content of the pressure-sensitive adhesive and to increase the shrinkage rate of the polarizing plate after the durability test. At this time, the distribution of the absorption axis of the polarizing plate was small, and light leakage was good.

A polarizing plate subjected to a durability test without bonding the polarizing plate to the panel and free contracted was found to have a large shrinkage ratio but a small absorption axis distribution. It is thought that light leakage was improved by reducing the distribution of the absorption axis by reducing the gel content of the pressure-sensitive adhesive to bring the polarizing plate into a state close to free shrinkage.

The second method is to harden the pressure-sensitive adhesive by increasing the gel content of the pressure-sensitive adhesive, so that the polarizing plate bonded to the liquid crystal panel (glass plate) cannot be shrunk and the shrinkage rate of the polarizing plate is reduced. It is a method of doing. At this time, it has been found that the distribution of the absorption axis becomes smaller and the light leakage becomes better.

Furthermore, this phenomenon was noticeable in a polarizing plate in which a retardation layer was formed on the polarizing plate.
The retardation layer is formed by coating or transferring a liquid crystal material on the protective film of the polarizing plate. In particular, this phenomenon is prominent in a viewing angle widening polarizing plate (WV (wide view) polarizing plate) having a retardation layer formed by tilting and aligning discotic liquid crystals.

 [Cause of light leakage]

Consider the cause.

The polarizing plate is bonded to the front and back of the liquid crystal cell with an adhesive so that the absorption axis is 90 degrees (orthogonal). At this time, the transmittance of light that has passed through the front and back polarizing plates is the smallest (darkest angle). When the absorption axes of the front and back sides of the bonded polarizing plates are shifted, the light transmittance increases and light leakage occurs.

In VA polarizing plates and IPS polarizing plates often used in liquid crystal televisions, the absorption axis is orthogonal or parallel to the sides of the polarizing plates. Since the direction of contraction is parallel or orthogonal to the side of the polarizing plate because it expands and contracts in the direction of the absorption axis, there is not much shift in the absorption axis due to expansion and contraction of the polarizing plate.

In the polarizing plate for TN and the polarizing plate for WV, the absorption axis is 45 degrees or 135 degrees with respect to the side of the polarizing plate. This is shown in FIG.

However, when the distribution of the absorption axis after the durability test was measured for a general TN polarizing plate having no retardation layer, it was found that the distribution of the absorption axis was much smaller than that of the WV polarizing plate (FIG. 38).

In addition, the measurement of the absorption axis is usually measured by applying light from a glass plate as shown in FIG. 3, but conversely, when measuring the distribution of the absorption axis by applying light from the polarizing plate side, in the case of a polarizing plate for WV, It was found that the distribution of the absorption axis measured from the glass plate was very small. This is because the misalignment 1 measured by applying light from the glass plate side is affected by the retardation of the adhesive layer, the WV layer, and the TAC film, but the misalignment 2 measured by applying light from the polarizing plate is TAC. This is considered to be due to only the influence of the film (FIG. 37).

Furthermore, when various polarizing plates are stressed in the direction of 45 degrees with respect to the absorption axis, in the WV polarizing plate, the angle of the absorption axis changes greatly in proportion to the stress. It was found that the angle of the absorption axis does not change much with the magnitude of stress in the TN polarizing plate without a retardation layer.

From the above, it is considered that the distribution of the absorption axis of the polarizing plate for WV occurs due to a large change in retardation due to distortion of the retardation layer (discotic liquid crystal layer) due to contraction of the polarizing plate.

It was found that the light leakage of the liquid crystal panel can be improved not only by the absorption axis distribution but also by reducing the polarization degree (V) distribution of the polarizing plate after the durability test. The polarization degree of the polarizing plate was measured to change when the incident angle of the linearly polarized light was changed even before the durability test, but the change of the polarization degree after the durability test was changed to the incident linearly polarized light axis. It turns out that it changes more than the change by the angle. This is shown in FIG.

The change in the degree of polarization after the durability test is considered to be caused by three points: 1 due to contraction of the polarizing plate, 2 misalignment of the absorption axis, TAC birefringence 3, and adhesive birefringence. The above difference is considered to be caused by cause 2 or cause 3.

Regarding cause 2, by reducing the thickness of the TAC, a method of reducing light leakage even when stress is applied to the TAC or birefringence occurs, or a film having a smaller photoelastic coefficient than TAC (for example, cycloolefin type) (IDW 2003 689 FMC9-2 FUJIFILM Nippon Zeon Co., Ltd. ZEONOR catalog).

Regarding cause 3, by accurately measuring the birefringence of the adhesive (adhesive intrinsic birefringence) and reducing its absolute value, the distribution of the degree of polarization can be reduced and light leakage can be improved. It was.

As described above, in the polarizing plate for WV, it has been shown that the distribution of the absorption axis greatly affects the light leakage. A polarizing plate in which the sides of the polarizing plate are parallel or orthogonal to the absorption axis, such as a VA polarizing plate and an IPS polarizing plate, has a smaller absorption axis distribution than the WV polarizing plate.

  However, since the polarizing plate for VA and the polarizing plate for IPS are used for a large television, the required performance of light leakage is increased. In the case of these polarizing plates, it is necessary to design the absorption axis distribution and polarization degree distribution after the durability test to be smaller. As this method, it is effective to further reduce the absolute value of the intrinsic birefringence of the adhesive.

So far, we have studied the distribution of absorption axes in the surface of the polarizing plate with adhesive, but the transmittance increases when the absorption axes of the polarizing plates on the front and back sides of the liquid crystal panel are offset from orthogonal. Although there is no partial light leakage, light is transmitted as a whole and the contrast deteriorates. For this purpose, it is important to align and bond the liquid crystal panel so that the absorption axis is 90 ± 0.5 degrees or less.

When sticking a polarizing plate with an adhesive to a liquid crystal panel, the side of the polarizing plate is aligned and attached to the liquid crystal panel. For this reason, it is important to align the sides of the polarizing plate at a constant angle with respect to the angle of the absorption axis and to cut accurately. In the case of a polarizing plate for WV, it is necessary to process the side of the polarizing plate at an angle (45 degrees or 135 degrees) determined with respect to the absorption axis to 0.5 degrees or less.

The polarizing plate for VA or the polarizing plate for IPS needs to process the side of the polarizing plate within 0 ° or 90 ° to 0.5 ° with respect to the absorption axis.

 [Relationship between absorption axis θp distribution and light leakage]

The relationship between the distribution of the absorption axis θp and light leakage will be described.

When the birefringence measuring apparatus is rotated by applying linearly polarized light to the polarizing plate, an angle at which the light transmittance is minimized is observed. This angle is referred to as an absorption axis angle (θp) of the polarizing plate. The light transmittance at this time is called orthogonal transmittance (Tc).

The transmittance (T) increases as it deviates from θp. Assuming that the deviation angle from θp is Δθ, T is theoretically a trigonometric function of Δθ, but when Δθ is small, it is approximated by a quadratic function.
When these are measured for the polarizing plate, it becomes as shown in FIG.
Transmittance T = 0.0206 × Δθ ^-2 + α
The relationship was obtained.

It can be seen that the transmittance increases by 0.0206% when Δθ is shifted by 1 degree.

Further consider the distribution of θp and Tc.

Measure θp and Tc at points A and B of the polarizing plate. The absorption axis at point A is θpA and the orthogonal transmittance TcA. The absorption axis at point B is θpB, and the orthogonal transmittance is TcB.

The transmittance at point B is TcB at θpB, but is shifted from point A by Δθ = | θpB−θpA |, so the transmittance TB at point B when the angle is θpA is TB
TB = TcB + 0.0206 × Δθ
= TcB + 0.0206 × │θpA−θpB│
become.

If the angle of the linearly polarized light incident on the polarizing plate is constant regardless of the location and θpA, the transmittance difference Ts between point A and point B is
Ts = (TB-TcAn)
= │TcB − TcA│ + 0.0206 × Δθ
become.

As described above, the difference in the transmittance becomes larger as the difference in the absorption axis Δθ in the polarizing plate becomes larger than the difference in the orthogonal transmittance measured in that place. This is shown in FIG.

In an actual WV polarizing plate, the distribution of the initial absorption axis θp is small, but after the durability test, the distribution of the absorption axis becomes large. Furthermore, after the durability test, the absorption axis at each location is distributed in the positive and negative directions with respect to the angle at which the transmittance is minimized. This distribution is the same for the upper and lower polarizing plates of the liquid crystal panel. When viewed from one direction, the upper and lower polarizing plates are misaligned at the same position. Each shifts in the opposite direction. This is shown in FIG. 7, FIG. 9, and FIG. In FIG. 7, the light arrow indicates the absorption axis of the upper polarizing plate, and the dark arrow indicates the direction of the absorption axis of the lower polarizing plate.

The difference between the darkest part and the brightest part of the light leakage of a liquid crystal display using an actual WV polarizing plate (the range of light transmittance distribution) is that of the polarizing plate bonded to the glass measured with a birefringence measuring device. The difference in transmittance is considered to be about twice the largest value. (The absorption axis of the upper and lower polarizing plates is shifted between plus and minus. Therefore, when two upper and lower polarizing plates are used, it is considered that the transmittance distribution when measured with one polarizing plate is doubled.)

In addition, since the brightness of the polarizing plate actually changes depending on the vision, it is actually more appropriate to use the value corrected with the visibility for the transmittance at each wavelength for visible light from 400 nm to 800 nm as the visibility corrected transmittance. Yes. Visibility corrected orthogonal transmittance (Yc) was obtained by correcting the transmittance at the absorption axis for each wavelength.

Further, the visual superiority or inferiority of the light leakage may be not only the difference between the maximum value and the minimum value of the light transmittance, but also the case where the light leakage is more suitable. (The standard deviation of the transmittance distribution is calculated, and the value three times as 3σ is assumed to be 3σ.) It is also considered that the distribution of the visibility corrected orthogonal transmittance is close to the actual appearance of light leakage.

 [Results of distribution measurement of absorption axis and degree of polarization]

This will be described below with specific measurement values. Regarding the distribution of the absorption axis, the orthogonal transmittance, the visibility corrected orthogonal transmittance, and the polarization degree, a value that is three times the standard deviation is described as 3σ.

(1) When the distribution in the plane of the initial absorption axis θp before the durability test was measured for the WV polarizing plate, it was as small as 3σ = 0.338 (Reference Example 1).

(2) The distribution of θp in the plane after being subjected to a durability test at 80 ° C. for 7 days without attaching the polarizing plate for WV to the glass plate was a small value of 3σ = 0.538 (reference) Example 2).

This is shown in FIG.

(3) The in-plane distribution of θp and Yc was measured after bonding a polarizing plate for WV with pressure-sensitive adhesive processed with various pressure-sensitive adhesives to a glass plate and taking 7 days at 80 ° C.

The figure which represented the distribution of the absorption axis of Example 1 and Comparative Example 5 with the contour line seen from the polarizing plate is shown. The values of the actually measured absorption axis are shown by calculating how many degrees each axis is offset by taking the absorption axis at the point where the orthogonal transmittance is minimum as 0 degree.

This is shown in FIGS.

  Although there is almost no distribution of the absorption axis in FIG. 9, it can be seen in FIG. 10 that the portion near the left and right sides of the polarizing plate is offset in the plus direction and the portion near the top and bottom sides is shifted in the minus direction.

  This contour line corresponds to the portion where light leaks and the portion where the axial deviation is large in the photograph of light leakage of Comparative Example 5. This is shown in FIG.

  About an Example and a comparative example, the graph about the absorption axis (theta) p in each point of a polarizing plate, the visibility correction orthogonal transmittance | permeability Yc, and a polarization degree (V) is shown. This is shown in FIGS.

  It can be seen that the distribution of the absorption axis θp, the visibility corrected orthogonal transmittance Yc, and the degree of polarization (V) varies greatly depending on the adhesive.

 [Relationship between misalignment and light leakage]

Consider the absorption axis θp, the visibility corrected orthogonal transmittance Yc, and the degree of polarization (V) of each polarizing plate after the durability test. The greater the distribution of θp, the greater the distribution of Yc. This is shown in FIG.

The distribution of V increases as the distribution of θp increases. This is shown in FIG.

Accordingly, as a result of investigating the correlation of θp3σ and Yc3σ, which is three times the standard deviation of θp and Yc at each point on the polarizing plate surface, as shown in FIG.

  FIG. 14 shows that Yc3σ is small when the θp3σ value is 1.3 degrees or less, but is large when the value is 1.3 degrees or more. In an actual light leakage test, it was also found that a polarizing plate having a θp3σ value of 1.3 ° or less has better light leakage than a polarizing plate having a value of 1.3 ° or more. This is shown in FIG.

Further, as a result of examining the correlation between the difference between the maximum value and the minimum value of θp at each point on the same polarizing plate surface and Yc3σ which is three times the standard deviation of Yc, the result is as shown in FIG.

From FIG. 16, it can be seen that 3c of Yc is a small value when the difference between the maximum value and the minimum value of θp is 1.5 degrees or less, but becomes a large value when the difference is 1.5 degrees or more. Further, in an actual light leakage test, it was found that a polarizing plate having a difference between the maximum value and the minimum value of θp of 1.5 degrees or less has better light leakage than that of 1.5 degrees or more (FIG. 17). ).

  For the same polarizing plate, the correlation between the absorption axis θp at each point on the polarizing plate surface and the standard deviation of the polarization degree V, which is three times the standard deviation θp3σ and Vc3σ, is shown in FIG.

  FIG. 18 shows that the polarization distribution V3σ is a small value when the absorption axis distribution θp3σ is 1.3 degrees or less, but is a large value when the value is 1.3 degrees or more. Further, it has been found that a polarizing plate having a V3σ value of 0.3 or less has good light leakage even in an actual light leakage test (FIG. 19).

 [Shrinkage rate and misalignment of polarizing plate]

Furthermore, the shrinkage of the polarizing plate was measured.

FIG. 20 shows a view of the corners observed from the top when the polarizing plate is bonded to a glass plate and contracted. As shown in the figure, when the polarizing plate contracts, the adhesive is observed after flowing.

It is considered that the cross section is as shown in FIG. Therefore, the displacement (d) of the pressure-sensitive adhesive was measured, and the shrinkage rate of the polarizing plate was measured by the following formula.

The deviation amount (d) was obtained by averaging the deviations in the vertical and horizontal directions at the four corners of the polarizing plate.

Shrinkage rate = L1 / L = (L-2d) / L

FIG. 22 shows the distribution of shrinkage and absorption axis for various adhesives. FIG. 23 shows the gel content and shrinkage of the adhesive.

FIG. 23 shows that the smaller the gel content, the greater the shrinkage rate. From FIG. 22, only the polarizing plate is contracted, but the contraction rate is large, but the distribution of the absorption axis is small (Reference Example 2).

In Examples 4 and 5 with the best light leakage, the shrinkage ratio is large but the distribution of the absorption axis is small, similar to the case where only the polarizing plate is contracted. In Examples 1, 2, and 3 with good light leakage, the shrinkage rate is small and the distribution of the absorption axis is also small. It was found that Comparative Examples 1 and 2 with poor light leakage had a medium shrinkage rate but a large distribution of shrinkage axes.

 [Absorption axis distribution of polarizing plate for WV]

(1) About the same polarizing plate as Example 3, it measured by applying light from the polarizing plate surface after 80 degreeC 7 days.

  The relationship between θp and Yc measured from the glass surface and the polarizing plate surface was graphed.

  It was found that the distribution of θp measured from the polarizing plate surface was very small (FIG. 24).

(2) The relationship between θp and Yc measured from the glass surface and the polarizing plate surface after 7 days at 80 ° C. for the same pressure-sensitive adhesive used in Example 3 by changing the polarizing plate to a polarizing plate for TN (FIG. 25). ). These were all about 3σ = 0.1, and were small values regardless of the direction of light and the type of adhesive.

(3) Absorption axis changes when stress is applied to each polarizing plate in the direction of 45 degrees with respect to the absorption axis, while VA and TN polarizing plates do not change, but WV polarizing plates are proportional to the stress. The absorption axis changes (FIGS. 31 and 32).

From the above, it is considered that the axial deviation is caused by the stress applied to the WV layer.

A VA polarizing plate and an IPS polarizing plate were studied in which the absorption axis of the polarizing plate was 0 ° or 90 ° with respect to the side of the polarizing plate. Since the polarizing plate for VA is used in a large TV or the like, 195 points were measured for a 14 inch polarizing plate for the measurement of birefringence.

A birefringence measuring apparatus after a polarizing plate with a pressure sensitive adhesive (14 inches) obtained by processing the pressure sensitive adhesive shown in Table 4 on a glass plate is put on a glass plate at 80 ° C. for 7 days and left at room temperature for 1 day. Various measurements were performed. The absorption axis and polarization degree distribution of each polarizing plate are shown in FIG. It can be seen that the behavior is slightly different from the graph of the polarizing plate for WV.

FIG. 27 shows the distribution on the surface of the absorption axis and polarization degree of each polarizing plate, which is three times the standard deviation (3σ).

The absorption axis distribution θp3σ was all 0.3 degrees or less. This is probably because the absorption axis is processed at 0 ° or 90 ° with respect to the side of the polarizing plate, so that even if the polarizing plate contracts, the absorption axis is hardly shifted.

Furthermore, as a result of measuring these light leaks, it was found that the light leakage is good when the absorption axis distribution θp3σ is 0.2 degrees or less or when the polarization degree V distribution is 0.1 or less.

The pressure-sensitive adhesive birefringence values of these pressure-sensitive adhesives were measured, and it was found that the smaller the pressure-sensitive adhesive birefringence value, the better the light leakage, and the light leakage was better at 4 × 10 ⁻⁴ or less. .

<Adhesive and production method thereof>

  An example of the polymer used for the pressure-sensitive adhesive of the present invention will be described.

  Examples of the polymer that can be used for the pressure-sensitive adhesive include acrylic polymers, urethane polymers, styrene elastomers such as styrene / isoprene (SIS), polyester polymers, and olefin polymers.

  Examples of the acrylic polymer include at least one selected from an alkyl ester monomer having 1 to 18 carbon atoms of (meth) acrylic acid and a copolymerizable monomer having an aromatic ring, a carboxyl group and a hydroxyl group. Examples thereof include a copolymer with a copolymerizable monomer having at least one.

  Examples of the urethane polymer include compounds obtained by reacting diols with diisocyanates.

  Examples of the styrene elastomer include SIS (styrene / isoprene / styrene block copolymer), SBS (styrene / butadiene / styrene block copolymer), ESBS (epoxidized styrene / butadiene / styrene copolymer), and the like. .

  Hereinafter, the acrylic polymer will be described in more detail.

  Examples of the alkyl ester monomer having 1 to 18 carbon atoms of (meth) acrylic acid include methyl (meth) acrylate, ethyl (meth) acrylate, propyl (meth) acrylate, butyl (meth) acrylate, and isobutyl (meth) ) Acrylate, 2-ethylhexyl (meth) acrylate, octyl (meth) acrylate, isooctyl (meth) acrylate, isononyl (meth) acrylate, alkyl (meth) acrylate such as lauryl (meth) acrylate, and the like. It may be used alone or in combination of two or more.

  Examples of the copolymerizable monomer having an aromatic ring include monomers having an aromatic ring such as phenoxyethyl (meth) acrylate, benzyl (meth) acrylate, styrene, and α-methylstyrene. These may be used alone or in combination of two or more.

  Examples of the copolymerizable monomer having at least one of a carboxyl group and a hydroxyl group include (meth) acrylic acid, carboxyethyl (meth) acrylate, 2-hydroxyethyl (meth) acrylate, and 2-hydroxy. Propyl (meth) acrylate, 4-hydroxybutyl (meth) acrylate, 6-hydroxyhexyl (meth) acrylate, 8-hydroxyoctyl (meth) acrylate, 10-hydroxydexyl (meth) acrylate, 12-hydroxylauryl (meth) Examples thereof include acrylate and hydroxyethyl (meth) acrylamide.

  The acrylic polymer may further be copolymerized including a dialkyl-substituted acrylamide monomer and an acetoacetyl group-containing monomer.

  Dialkyl substituted acrylamide monomers include N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, N-ethyl-N-methyl (meth) acrylamide, and N, N-dibutyl (meth) acrylamide. N, N-dipropyl (meth) acrylamide, N, N-diisopropyl (meth) acrylamide, N-methyl N-propyl acrylamide, N-methyl N-isopropyl acrylamide and the like. N, N-dimethyl (meth) acrylamide, N, N-diethyl (meth) acrylamide, and N-ethyl-N-methyl (meth) acrylamide are preferable.

  As the acetoacetyl group-containing monomer, acetoacetoxyethyl acrylate, acetoacetoxyethyl methacrylate, acetoacetoxyethyl crotonate, acetoacetoxypropyl acrylate, acetoacetoxypropyl methacrylate, acetoacetoxypropyl crotonate, 2-cyanoacetoacetoxyethyl methacrylate, N- (2-acetoacetoxyethyl) acrylamide, N- (2-acetoacetoxyethyl) methacrylamide, allyl acetoacetate, vinyl acetoacetate and the like can be mentioned. Acetoacetoxyethyl acrylate and acetoacetoxyethyl methacrylate are preferred.

  The monomer is polymerized to synthesize a polymer.

As this polymerization method, usual solution polymerization, bulk polymerization, emulsion polymerization, suspension polymerization, and the like can be applied. However, it is preferable to produce the polymerization by solution polymerization in which the copolymer is obtained as a solution. By obtaining the copolymer as a solution, it can be used as it is for the production of the pressure-sensitive adhesive composition of the present invention. Examples of the solvent used for the solution polymerization include organic solvents such as ethyl acetate, toluene, n-hexane, acetone, and methyl ethyl ketone.

  Examples of the polymerization initiator used in the polymerization include peroxides such as benzoyl peroxide and lauryl peroxide, azobis compounds such as azobisisobutyronitrile and azobisvaleronitrile, and polymer azo polymerization initiators. These can be used alone or in combination. Moreover, in the said superposition | polymerization, in order to adjust the molecular weight of a copolymer, a conventionally well-known chain transfer agent can be used.

  In the above polymerization, monomers (monomers) corresponding to the repeating units determined using the above-described birefringence evaluation method are polymerized at the determined ratio.

  The acrylic polymer obtained by polymerization is cross-linked by a cross-linking agent.

As a crosslinking agent for crosslinking the acrylic polymer, a conventional polyglycidyl compound having two or more glycidyl groups in one molecule, a polyisocyanate compound having two or more isocyanate groups in one molecule, and one molecule A polyaziridine compound having two or more aziridinyl groups, a polyoxazoline compound having two or more oxazoline groups in a molecule, a metal chelate compound, or a butylated melamine compound can be used. Preferably, the polyisocyanate compound, polyglycidyl compound and metal chelate compound can be used alone or in combination of two or more.

  Examples of the metal chelate compound include compounds in which a polyvalent metal such as aluminum, iron, copper, zinc, tin, titanium, nickel, antimony, magnesium, vanadium, chromium and zirconium is coordinated to acetylacetone or ethyl acetoacetate. Preferably, an aluminum chelate compound and a titanium chelate compound are mentioned.

  Examples of the polyisocyanate compound include isocyanate compounds such as tolylene diisocyanate, xylylene diisocyanate, chlorophenylene diisocyanate, hexamethylene diisocyanate, tetramethylene diisocyanate, isophorone diisocyanate, diphenylmethane diisocyanate, and trimethylolpropane. And the like, and isocyanate compounds, isocyanurate compounds, burette type compounds, and urethane prepolymer type isocyanates obtained by addition reaction of polyether polyols, polyester polyols, acrylic polyols, polybutadiene polyols, polyisoprene polyols, and the like.

  With the cross-linking agent, the acrylic polymer undergoes a cross-linking reaction with time, and the content of the cross-linked structure increases. When a certain time elapses, the ratio of the crosslinked structure becomes constant.

  Further, a compound having at least two aromatic rings in the molecule may be blended prior to the addition of the crosslinking agent or at the time of the addition of the crosslinking agent.

  Examples of the compound having at least two aromatic rings in the molecule include biphenyl, diphenylsulfone, 4-phenylphenol, benzoin, diphenyl sulfide, diphenyl ether, 4-hydroxybiphenyl-4′-carboxylic acid, 4,4′-biphenol, 4,4′-dihydroxydiphenylmethane, 4-α-cumylphenol, diphenylacetylene, azobenzene, dibenzofuran, diphenylmethane, benzyl benzoate, diphenyl phthalate, N- (4-methoxybenzylidene) -4-acetoxyaniline, 4- [ (Methoxybenzylidene) amino] azobenzene, 4,4′-sulfonyldiphenol, 4-phenoxyphenol, 4′-methoxybenzylideneaminostilbene, bisphenol A, benzylidenephenylamino N, N′-dibenzylidenehydrazine, transstilbene, p-dianisalbenzidine, terephthalbis- (p-phenetidine), carbazole, 1,4-diphenyl-1,3-butadiene, 1,4-diphenyl-1 , 3,5-hexadiene, fluorene and dibenzothiophene, diethylene glycol dibenzoate, dipropylene glycol dibenzoate, benzyl benzoate, 1,4-cyclohexanedimethanol dibenzoate, tricresyl phosphate, trixylenyl phosphate, cresyl diphenyl phosphate, 2-ethylhexyl diphenyl phosphate is mentioned.

  Among these compounds, it is more preferable to use at least one selected from the group consisting of transstilbene, fluorene, diphenyl sulfide, benzyl benzoate, dipropylene glycol dibenzoate, benzoin, and diphenylacetylene.

The pressure-sensitive adhesive of the present invention can also be used as a UV crosslinking type. In the UV-crosslinking type pressure-sensitive adhesive, a monofunctional monomer or a polyfunctional monomer and a photopolymerization initiator are further added.
The monofunctional monomer preferably has at least one aromatic ring. Specifically, nonylphenyl EO modified acrylate, nonylphenyl PO modified acrylate, 2-hydroxy-3-phenoxypropyl acrylate and phthalic acid mono It is preferable to include at least one selected from hydroxyethyl acrylate.

  Examples of the polyfunctional acrylate include ethylene oxide-modified di (meth) acrylate, diacryloxyethyl isocyanurate, propylene oxide-modified trimethylolpropane tri (meth) acrylate, trisacryloxyethyl isocyanurate, trimethylolpropane tri (meth) acrylate, ε Caprolactone modified trisacryloxyethyl isocyanurate, pentaerythritol tetra (meth) acrylate, diglycerin tetra (meth) acrylate, propionic acid modified dipentaerythritol penta (meth) acrylate, caprolactone modified dipentaerythritol hexa (meth) acrylate, etc. Preferably, ε-caprolactone-modified trisacryloxyethyl isocyanurate, diacryloxyethyl Examples include isocyanurate di- or tri (meth) acrylates such as isocyanurate and trisacryloxyethyl isocyanurate.

  As the photopolymerization initiator used for the UV-crosslinking type pressure-sensitive adhesive, a conventional photopolymerization initiator by radiation (ultraviolet rays) can be used. For example, aminoketone series, hydroxyketone series, acylphosphine oxide series, benzyldimethyl ketal series, Examples include benzophenone-based, trichloromethyl group-containing triazine derivatives. Specifically, 1-hydroxycyclohexyl phenyl ketone, 2-hydroxy-2-methyl-1-phenylpropan-1-one, 2,4,6-trimethylbenzoylethoxyphosphine oxide, α-hydroxyketone, 2,4, Examples include 6-trimethylbenzophenone.

  You may add another additive further to the adhesive of this invention. Examples of such additives include antistatic agents, and applicable antistatic agents are not particularly limited. For example, a pyridinium cation having an alkyl group having 8 to 16 carbon atoms as a substituent on the nitrogen atom and no substituents from the α-position to the γ-position, a hexafluorophosphate anion, bis (fluorosulfonyl) ) Anion anion or a salt with bis (trifluoromethanesulfonyl) imide anion is mentioned, and it is preferably an ionic compound having an electric conductivity of 50 ms / m or more dissolved in toluene of 200 ms / m or more. 1-octylpyridinium, 1-nonylpyridinium, 1-decylpyridinium or 1-undecylpyridinium is preferred.

  The pressure-sensitive adhesive of the present invention may further contain a silane coupling agent. These silane coupling agents are all known in the field of pressure-sensitive adhesives, and any known silane coupling agent can be used in the present invention.

  The pressure-sensitive adhesive of the present invention may be blended with various additives in a range that does not impair the effects of the present invention, depending on necessary properties such as the purpose of adjusting the adhesive strength. For example, terpene, terpene-phenol, coumarone indene, styrene, rosin, xylene, phenol, or petroleum tackifier resins, antioxidants, UV absorbers, fillers, pigments, etc. can do.

<Production of zero-zero birefringent polymer film>

In a glass sample tube, a total of 30 g of methyl methacrylate (MMA), 2,2,2-trifluoroethyl methacrylate (3FMA), and benzyl methacrylate (BzMA), and perbutyl O (manufactured by NOF Corporation) are used as monomers. 0.5% by mass with respect to the total amount, and 0.3% by mass of n-butyl mercaptan with respect to the total amount of monomers were added. The monomer ratio (mass ratio) was MMA / 3FMA / BzMA = 55.5 / 38.0 / 6.5.

  These were stirred, dissolved, and sufficiently homogenized, then filtered through a PTFE membrane filter (Toyo Roshi Kaisha, Ltd.) having a pore size of 0.2 μm, and transferred to a test tube. This test tube was placed in a 70 ° C. water bath and polymerized for 24 hours. Subsequently, heat treatment was performed in a dryer at 90 ° C. for 24 hours.

  The polymer taken out from the test tube was put into a glass sample tube together with 4 times the amount of tetrahydrofuran by mass ratio, stirred and sufficiently dissolved. The obtained polymer solution was developed into a glass plate using a knife coater, left at room temperature for one day, and dried. The formed film was peeled off from the glass plate and further dried in a vacuum dryer at 60 ° C. for 48 hours. The obtained film having a thickness of about 35 μm was processed into a dumbbell shape, and uniaxially stretched by a Tensilon general-purpose tester (manufactured by A & D Co., Ltd.). The stretching temperature was 102 ° C., the stretching speed was 400% / min, and the stretching ratio was 1.2 to 2.7 times.

After the stretched film was cooled to room temperature and allowed to stand at room temperature for 24 hours, the retardation produced in the film was measured using an automatic birefringence measuring apparatus ABR-10A (Uniopt Co., Ltd.). Furthermore, the thickness of the stretched film was measured using a micrometer. As a result, the absolute value of intrinsic birefringence was less than 1 × 10 ⁻⁴ at any draw ratio, and the orientation birefringence was practically regarded as zero.

Among the above films, the photoelastic birefringence of the unstretched film was measured.
The above film was cut into a dumbbell shape shown in FIG. 30, a tensile stress was applied thereto, and birefringence was measured using an automatic birefringence measuring apparatus ABR-10A (Uniopto Corporation). As a result of obtaining the photoelastic constant from the relationship between the stress and the birefringence, the absolute value was less than 0.5 × 10 ⁻¹² Pa ⁻¹ , and the photoelastic birefringence was substantially considered to be zero.

  From the above, it was confirmed that the polymer film obtained as described above is a zero / zero birefringent polymer film in which neither orientation birefringence nor photoelastic birefringence occurs.

  [Production Examples 1 to 11 (Copolymers 1 to 11)]

Nitrogen gas was introduced into a reaction apparatus equipped with a stirrer, a thermometer, a reflux condenser, and a nitrogen introduction tube, and the air in the reaction apparatus was replaced with nitrogen gas. Thereafter, 0.1 parts of azobisisobutyronitrile as a polymerization initiator and 100 parts of ethyl acetate as a reaction solvent were added to the reactor. While stirring this, the mixture was reacted at 60 ° C. for 8 hours in a nitrogen gas stream, and then diluted with ethyl acetate to obtain an acrylic resin solution having a weight average molecular weight of 1,000,000 to 2,000,000. Furthermore, a crosslinking agent and additives as shown in Tables 2, 3, 4, and 5 were blended to prepare an adhesive precursor solution.

 [Measurement of birefringence of adhesive]

The obtained pressure-sensitive adhesive precursor solution was applied onto a film separator made of PET (Poly Ethylene Terephthalate) and dried, and then allowed to crosslink for 1 week at room temperature. This crosslinked film was attached to the previously prepared zero / zero birefringent polymer film. Then, the film separator was peeled off, and another zero / zero birefringent polymer film was attached to the cross-linked film on the peeled surface.

The thickness of the pressure-sensitive adhesive layer was about 30 μm, the thickness of each zero / zero birefringent polymer film was about 35 μm, and the total thickness was about 100 μm.

  This laminated film was processed into a dumbbell shape shown in FIG. 30, and uniaxially stretched by a Tensilon general-purpose tester (manufactured by A & D Co., Ltd.). The stretching temperature was 102 ° C., the stretching speed was 400% / min, and the stretching ratio was 2.0 times.

  The stretched laminated film was cooled to room temperature and allowed to stand at room temperature for 24 hours, and then the retardation produced in the film was measured using an automatic birefringence measuring apparatus ABR-10A (Uniopt Co., Ltd.).

The center part of the stretched film (the center part of the region sandwiched between the two gauge lines shown in FIG. 30) is embedded in an epoxy adhesive and hardened, and then cut and polished to bring out the cross section of the film. The thickness of the pressure-sensitive adhesive layer was measured.
The value obtained by dividing the retardation value by the thickness of the pressure-sensitive adhesive is taken as the pressure-sensitive adhesive birefringence.

 [Method of making polarizing plate with adhesive]

The resulting adhesive precursor solution was applied onto a film separator composed of PET and dried, and then allowed to crosslink for 1 week at room temperature. This crosslinked film was affixed to various polarizing plates.

The WV polarizing plate was attached to the WV film side, and the VA polarizing plate was attached to the retardation film side.

The thickness of the pressure-sensitive adhesive layer was about 25 μm.

Abbreviations of monomers BA: butyl acrylate MA: methyl acrylate PHEA: phenoxyethyl acrylate HEA: 2-hydroxyethyl acrylate AA: acrylic acid 4HBA: 4-hydroxybutyl acrylate DMAA: N, N-dimethylacrylamide AAEM: acetoacetoxyethyl methacrylate crosslinking Agent, additive Coronate L: Polyisocyanate Coronate 2030 manufactured by Nippon Polyurethane Industry Co., Ltd. Polyisocyanate Takenate D-120N manufactured by Nippon Polyurethane Industry Co., Ltd. Hydrogenated xylene diisocyanate compound IL-1451 manufactured by Mitsui Chemicals, Inc. Sumitomo Bayer Urethane Co., Ltd. Polyisocyanate Aluminum Chelate A: Kawaken Fine Chemical Co., Ltd. Aluminum Tris Acetyl Tetrad C: Mitsubishi Gas Chemical Co., Ltd. Manufactured polyglycidyl compound X-41-1810: manufactured by Shin-Etsu Chemical Co., Ltd. methyl mercapto-based alkoxy oligomer X-41-1056: manufactured by Shin-Etsu Chemical Co., Ltd. alkoxy oligomer

 [Measurement method with birefringence measuring device]

A 15 cm × 8 cm pressure-sensitive adhesive polarizing plate bonded to a glass plate having a thickness of 2 mm was irradiated with light perpendicularly from the glass surface side, and the absorption axis, orthogonal transmittance, and degree of polarization were measured by a single sheet method.
Birefringence measuring device RETS-RE1200 manufactured by Otsuka Electronics.

The distribution of the absorption axis, the visibility corrected orthogonal transmittance, and the degree of polarization was measured at a measurement point on the polarizing plate surface of 7 points at a 23.3 mm pitch and 5 points at a pitch of 18 mm and a total of 35 points. Measurement temperature 23 ° C 55% RH. This is shown in FIGS.

When the polarizing plate was bonded to a glass plate or a liquid crystal panel, the side of the polarizing plate was adjusted to be ± 0.5 degrees or less with respect to the set value using a bonding machine.

The polarizing plate uses RETS-RE1200 manufactured by Otsuka Electronics, and the average value of the darkest angle is measured so that the side of the polarizing plate is 45 ± 0.5 degrees or 135 ± 0.5 degrees with respect to the angle. Disconnected.

Moreover, if the distribution of the absorption axis at the initial stage of the polarizing plate is large, light leakage will not be improved even if the polarizing plate is bonded to the liquid crystal panel with high accuracy.

The distribution of the initial absorption axis depending on the location of the polarizing plate is also caused by variations in the direction of the stretching axis when the PVA is stretched during the production of the polarizing plate, but also varies depending on the storage state after the production of the polarizing plate.

 [Measurement method of absorption axis and polarization degree distribution of polarizing plate for VA]

A 14-inch polarizing plate with an adhesive is bonded to a 2 mm thick glass plate.
The distribution of the transmission axis and the degree of polarization was measured by using the Otsuka Electronics RETS-RE1200, and the darkest angle of the polarizing plate was taken as the absorption axis by the method of measuring the transmittance and the degree of polarization by a single sheet method. Furthermore, the orthogonal transmittance and the degree of polarization with respect to the absorption axis were obtained. Measurement temperature 23 ° C 55% RH.

In the case of a 14-inch pressure-sensitive adhesive polarizing plate, a total of 195 points were measured at a pitch of 15 mm in a 210 × 180 area.

 [Method for measuring shrinkage of polarizing plate]

As shown in FIG. 20, when the polarizing plate contracts, the adhesive is observed after flowing.

It is considered that the cross section is as shown in FIG. Therefore, the deviation amount (d) of the pressure-sensitive adhesive was measured with a calibrated microscope at a total of 8 points in the vertical and horizontal directions at four corners to obtain an average value, and the shrinkage of the polarizing plate was measured by the following formula.

Shrinkage rate = L1 / L = (L-2d) / L

 [Measurement of change in absorption axis when stress is applied to polarizing plate]

Various polarizing plates with pressure-sensitive adhesive are cut into a size of 15 mm × 60 mm so as to be 45 degrees or 135 degrees with respect to the absorption axis. A change in absorption axis was measured by applying a tensile load in the longitudinal direction with a birefringence measuring apparatus with a tension mechanism. When stress is applied in the direction of 45 degrees or 135 degrees with respect to the absorption axis, in the WV polarizing plate, the angle of the absorption axis changes greatly in proportion to the stress. It was found that the angle of the absorption axis did not change much depending on the magnitude of stress in the TN polarizing plate without (FIGS. 31 and 32).

<Test methods and evaluation criteria>

Here, the test method and evaluation criteria will be described.

[Gel fraction]

After 0.2 g of the crosslinked pressure-sensitive adhesive film was accurately weighed (W1) and immersed in 50 ml of toluene for 1 day, a 200-mesh wire mesh was weighed (W2). Next, filtration was performed to extract a soluble component. Then, it was made to dry and the weight (W3) of the insoluble part was calculated | required. The gel fraction (% by weight) was calculated from these measured values using the following formula.
Gel fraction (% by weight) = ((W3−W2) / W1) × 100

[Light leakage]

The same sample after 7 days test at 80 ° C. using the polarizing plate in Examples and Comparative Examples was bonded to the upper and lower surfaces of the liquid crystal panel in a crossed Nicol state, the backlight of the liquid crystal monitor was turned on, and the white area was blank Was visually observed.

The evaluation criteria are as follows.
A: No light leakage was observed on the polarizing plate. B: Little light leakage was observed on the polarizing plate.
Δ: Slight light leakage was observed on the polarizing plate.
X: Light leakage was observed in the polarizing plate.

 [Weight average molecular weight (Mw)]

This is a molecular weight in terms of polystyrene measured by GPC (GEL Permeation Chromatography) method. Specifically, the coating film obtained by drying the copolymer at room temperature was dissolved in tetrahydrofuran, and measured with a high performance liquid chromatograph (manufactured by Shimadzu Corporation, LC-10ADvp, column KF-G + KF-806 × 2). The weight average molecular weight (Mw) in terms of polystyrene was determined.

[Storage modulus]

 25 μm of the pressure-sensitive adhesive film after crosslinking was sandwiched between solid shear jigs, and the storage elastic modulus (G ′) at 30 ° C. and 80 ° C. was measured at a frequency of 1 Hz using Rheogel-E4000 manufactured by UBM Co., Ltd.

・ Reference examples 1 and 2
As a result of measuring the distribution of the absorption axis from the WV film side of the polarizing plate for WV, 3σ was as small as 0.338 before applying the durability test. Even when only the polarizing plate for WV was allowed to stand for 7 days at 80 ° C., the distribution of the absorption axis was as small as 0.538 at 3σ.

Examples 1, 2, 3
Increasing the amount of isocyanate-based crosslinking agent (Coronate L) increased the gel fraction of the pressure-sensitive adhesive and decreased the shrinkage of the polarizing plate. Since the amount of deformation of the polarizing plate is reduced, the absorption axis distribution is also considered to be reduced. Although the stress applied to the polarizing plate increases, the distribution of orthogonal transmittance and the degree of polarization decreases because the area to which the stress is applied is small. It was found that the actual light leakage was also improved.

Examples 4 and 5
When the gel content was 40% or less, the contraction rate of the polarizing plate also increased. Although the amount of deformation of the polarizing plate increases, the stress applied to the polarizing plate is small, and therefore the absorption axis distribution is considered to be small. Further, both the orthogonal transmittance distribution and the polarization degree distribution become smaller. It was found that the actual light leakage was also improved.

Comparative examples 1 and 2
In Comparative Examples 1 and 2 having a gel content of 50% and 60%, both the gel content and the shrinkage ratio were values between Examples 1, 2, 3 and Examples 4 and 5. However, since the deformation amount of the polarizing plate and the stress applied to the polarizing plate are increased to some extent, the distribution of the absorption axis is increased. Furthermore, the distribution of the orthogonal transmittance and the distribution of the polarization degree were large values. It turns out that the actual light leakage is not good.

Examples 6 to 10
The composition of the copolymer was examined by changing the ratio of BA and PHEA, but the absorption axis distribution was reduced by increasing the gel content by increasing the amount of the crosslinking agent. Moreover, it was found that both the orthogonal transmittance distribution and the polarization degree distribution are small, and the actual light leakage is also good.

Comparative example 3
The composition of the copolymer was almost the same as in Example 8, but the amount of cross-linking agent was reduced to a gel fraction of 50%. The distribution of the absorption axis increased, and both the orthogonal transmittance distribution and the polarization degree distribution were large. It turns out that the actual light leakage is not good.

Reference examples 3, 4, 5
The same pressure-sensitive adhesive as in Example 3 was applied to a polarizing plate for WV and a polarizing plate for TN, and the distribution of the absorption axis after 7 days at 80 ° C. was irradiated with light from the polarizing plate surface and the glass surface. The distribution of the absorption axis was measured and all values were small.

Examples 11, 12, and 13
A VA polarizing plate processed with the adhesive shown in Table 4 was bonded to a glass plate, and the distribution of the absorption axis and the degree of polarization was measured, but the value was small. The absolute value of the intrinsic birefringence of these adhesives was small. Good results were obtained when light leakage was observed on both sides of the liquid crystal panel.

Comparative example 4
The VA polarizing plate processed with the pressure-sensitive adhesive of Comparative Example 4 was bonded to a glass plate, and the distribution of the absorption axis and the degree of polarization was measured. However, the distribution of the absorption axis was small. The distribution of the degree of polarization was a large value. The absolute value of the inherent birefringence of the adhesive was as large as 8 × 10 ⁻⁴ . When it was arranged on both sides of the liquid crystal panel and light leakage was observed, good results were not obtained.

Examples 14 to 21 and Comparative Example 5
The distribution of the absorption axis, light leakage, gel content, and storage viscoelasticity of the pressure-sensitive adhesive in which the type and amount of the cross-linking agent were changed to the WV polarizing plate in the formulation shown in Table 5 were measured.

As a result, the larger the amount of the cross-linking agent, the smaller the absorption axis distribution, the polarization degree distribution, and the Yc distribution. Moreover, as the amount of the crosslinking agent increased, the gel fraction and the storage elastic modulus at 20 ° C. and 80 ° C. increased. The greater the amount of the crosslinking agent, the better the light leakage. In Comparative Example 5, the distribution of the absorption axis was 1.453, the difference between the maximum value and the minimum value of the absorption axis was as large as 0.1544, and the light leakage was bad.

FIG. 35 and FIG. 36 show a photograph of these light leaks and a distribution of axial deviation.

 [About polarizing plate]

1. Polarizing plate for WV
For example, it is a polarizing plate using a viewing angle widening film (WV film, manufactured by Fuji Film) for TN mode TFT-LCD.

  The viewing angle widening film is obtained by processing a discotic liquid crystal on one side of a TAC film.

  Usually, bonding is performed so that the absorption axis is 45 degrees or 135 degrees with respect to the side of the liquid crystal panel. What is mainly used in this embodiment is the configuration 1. It is. This is mainly used in LCD monitors and notebook computers.

Configuration 1 (current mainstream) TAC / PVA / TAC / WV / PSA / TN liquid crystal cell / PSA / WV / TAC / PVA / TAC
A viewing angle widening film is integrated with the polarizing plate.

Configuration 2 (previous configuration)
TAC / PVA / TAC / PSA / TAC / WV / PSA / TN liquid crystal cell / PSA / WV / TAC / PSA / TAC / PVA / TAC
The viewing angle widening film is bonded with an adhesive separately from the polarizing plate.

TAC: TAC film, PVA: PVA film impregnated with iodine and stretched
WV: Discotic liquid crystal layer, PSA: Adhesive

2. TN (Twisted Nematic) polarizing plate For example, a polarizing plate that does not include a retardation layer.

Structure TAC / PVA / TAC / PSA / TN liquid crystal cell / PSA / TAC / PVA / TAC

It is used in calculators and household appliances.

3. Polarizing plate for VA (Vertical Alignment, vertical alignment) For example, it is a polarizing plate used for VA mode LCD.

    There are one in which the retardation film is integrated with the polarizing plate, and one in which the retardation film is bonded to the polarizing plate with an adhesive. Some use two retardation films on one side.

A polarizing plate for VA is bonded to one side or both sides of a VA liquid crystal cell. In the case of one side, a polarizing plate without a retardation film is used on the other side. Bonding is performed so that the absorption axis is 0 degree or 90 degrees with respect to the side of the liquid crystal panel.

What was used by the above-mentioned embodiment is a type which can be bonded on both surfaces of a liquid crystal cell with the polarizing plate which the retardation film integrated.

4. Polarizing plate for IPS (In-Plane Switching) In the IPS mode LCD, for example.

A polarizing plate is prepared using a film with or without retardation. In many cases, a polarizing plate and a retardation film are integrated.

These are shown in FIG.

 [Definition and symbols]

θp: absorption axis (darkest angle of polarizing plate)
T0: transmittance on the absorption axis T90: transmittance on the transmission axis
Tc: Orthogonal transmittance T0 × T90
Yc: Visibility corrected orthogonal transmittance Orthogonal transmittance obtained by correcting visibility for transmittance measured from 400 nm to 800 nm V: Polarization degree (%) V = SQR ((T90−T0) / (T90 + T0)) × 100

 [Interpretation of rights, etc.]

The present invention has been described above with reference to specific embodiments. However, it is obvious that those skilled in the art can make modifications or substitutions of the embodiments without departing from the gist of the present invention. That is, the present invention has been disclosed in the form of exemplification, and the contents described in the present specification should not be interpreted in a limited manner. In order to determine the gist of the present invention, the claims section described at the beginning should be considered.

It will also be appreciated that illustrative embodiments of the invention achieve the above objects, but that many modifications and other examples can be made by those skilled in the art. The elements or components of each embodiment described in the claims, specification, drawings, and description may be employed in combination with one or more other elements. The claims are intended to cover such modifications and other embodiments, which are within the spirit and scope of the present invention.

The first aspect of the present invention is
A polarizing plate with an adhesive designed to improve light leakage by reducing the distribution of the absorption axis after the durability test of the polarizing plate with an adhesive bonded to a glass substrate.
It is in.
The second aspect of the present invention is
To improve light leakage so that the distribution of the absorption axis after a heat resistance test at 80 ° C. for 7 days of the pressure-sensitive adhesive polarizing plate bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. Designed polarizing plate with adhesive.
It is in.
The third aspect of the present invention is
Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. The polarizing plate with an adhesive.
It is in.
The fourth aspect of the present invention is
4. The polarizing plate with an adhesive according to claim 1, wherein the gel content of the adhesive is 0.1% or more and 40% or less.
It is in.
The fifth aspect of the present invention provides
The polarizing plate with an adhesive according to any one of claims 1 to 3, wherein a gel content of the adhesive is 80% or more and 99% or less.
It is in.
The sixth aspect of the present invention provides
6. The polarizing plate with an adhesive according to claim 1, wherein the polarizing plate is a polarizing plate for WV.
It is in.
The seventh aspect of the present invention provides
The polarizing plate with the pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the polarization degree distribution after being bonded to a glass substrate and subjected to a heat test at 80 ° C for 7 days is 0.2 or less in terms of three times the standard deviation.
It is in.
The eighth aspect of the present invention is
To improve light leakage so that the distribution of the absorption axis after the heat resistance test at 80 ° C. for 7 days of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. Designed polarizing plate with adhesive.
It is in.
The ninth aspect of the present invention provides
9. The polarizing plate with an adhesive according to claim 8, wherein the polarization degree distribution after the heat resistance test at 80 ° C. for 7 days after being attached to a glass substrate is 0.2 or less in terms of a triple value of the standard deviation.
It is in.
The tenth aspect of the present invention provides
10. The polarizing plate with the pressure-sensitive adhesive according to claim 9 , wherein an absolute value of pressure-sensitive adhesive intrinsic birefringence of the pressure-sensitive adhesive is 4 × 10 ⁻⁴ or less.
It is in.
The eleventh aspect of the present invention is
11. The polarizing plate with an adhesive according to claim 10 , wherein the polarizing plate is cut so that the absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate.
It is in.
The twelfth aspect of the present invention is
12. The polarizing plate with an adhesive according to claim 8, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS.
It is in.
The thirteenth aspect of the present invention is
A pressure-sensitive adhesive polarizing plate in which the pressure-sensitive adhesive is selected so as to improve light leakage by reducing the distribution of absorption axes after the durability test of the pressure-sensitive adhesive polarizing plate bonded to a glass substrate.
It is in.
The fourteenth aspect of the present invention provides
To improve light leakage so that the distribution of the absorption axis after a heat resistance test at 80 ° C. for 7 days of the pressure-sensitive adhesive polarizing plate bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. A polarizing plate with a pressure sensitive adhesive selected.
It is in.
The fifteenth aspect of the present invention is
Adhesive so as to improve light leakage so that the difference between the maximum value and the minimum value of the absorption axis of a polarizing plate with an adhesive bonded to a glass substrate after a heat test at 80 ° C. for 7 days is 1.5 degrees or less. A polarizing plate with a pressure-sensitive adhesive selected.
It is in.
The sixteenth aspect of the present invention is
To improve light leakage so that the distribution of the absorption axis after the heat resistance test at 80 ° C. for 7 days of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. A polarizing plate with a pressure sensitive adhesive selected.
It is in.
The seventeenth aspect of the present invention is
A pressure-sensitive adhesive polarizing plate in which the pressure-sensitive adhesive is selected so as to improve light leakage by reducing the distribution of the absorption axis and the degree of polarization after the durability test of the pressure-sensitive adhesive bonded to a glass substrate.
It is in.
The eighteenth aspect of the present invention provides
Measure the distribution of the absorption axis and the degree of polarization after the durability test of the polarizing plate with an adhesive bonded to a glass substrate, and select the adhesive so that the distribution of the absorption axis and the degree of polarization is small. A polarizing plate with an adhesive designed to improve light leakage.
It is in.
The nineteenth aspect of the present invention provides
19. A liquid crystal panel comprising the pressure-sensitive adhesive polarizing plate according to claim 1.
It is in.
The twentieth aspect of the present invention provides
An adhesive designed to improve light leakage by reducing the distribution of the absorption axis after the durability test of a polarizing plate with an adhesive bonded to a glass substrate.
It is in.
The 21st aspect of the present invention is
A pressure-sensitive adhesive that improves light leakage by reducing the distribution of the absorption axis and the distribution of the degree of polarization after a durability test of a polarizing plate with a pressure-sensitive adhesive bonded to a glass substrate.
It is in.
The twenty-second aspect of the present invention provides
Measure the absorption axis distribution and the polarization degree distribution after the durability test of the polarizing plate with adhesive attached to the glass substrate, and reduce the light leakage by reducing the absorption axis distribution and the polarization degree distribution. Improved adhesive.
It is in.
The other first aspect is
The pressure-sensitive adhesive polarizing plate is designed to improve light leakage by reducing the distribution of the absorption axis after the durability test of the pressure-sensitive adhesive polarizing plate bonded to the glass substrate.

The other second aspect is
To improve light leakage so that the distribution of the absorption axis after a heat resistance test at 80 ° C. for 7 days of the pressure-sensitive adhesive polarizing plate bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. It is in the designed polarizing plate with adhesive.

The other third aspect is
Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. It is in the polarizing plate with an adhesive.

The other fourth aspect is
4. The pressure-sensitive adhesive polarizing plate according to claim 1, wherein the pressure-sensitive adhesive has a gel content of 0.1% to 40%.

Another fifth aspect of the present invention is:
4. The pressure-sensitive adhesive polarizing plate according to claim 1, wherein the pressure-sensitive adhesive has a gel content of 80% or more and 99% or less.

Another sixth aspect of the present invention is:
6. The polarizing plate with an adhesive according to claim 1, wherein the polarizing plate is a polarizing plate for WV.

Another seventh aspect of the present invention is:
The pressure-sensitive adhesive polarizing plate according to any one of claims 1 to 6, wherein the distribution of the degree of polarization after a heat resistance test at 80 ° C for 7 days after being attached to a glass substrate is not more than 0.2 in terms of three times the standard deviation. is there.

Another eighth aspect of the present invention is:
To improve light leakage so that the distribution of the absorption axis after the heat resistance test at 80 ° C. for 7 days of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. It is in the designed polarizing plate with adhesive.

Another ninth aspect of the present invention is:
9. The polarizing plate with an adhesive according to claim 8, wherein the distribution of the degree of polarization after being bonded to a glass substrate and subjected to a heat test at 80 ° C. for 7 days is 0.2 or less in terms of a triple value of the standard deviation.

The other tenth aspect is
10. The pressure-sensitive adhesive polarizing plate according to claim 8, wherein an absolute value of the pressure-sensitive adhesive's intrinsic birefringence value is 4 × 10 ⁻⁴ or less.

The other eleventh aspect is
11. The pressure-sensitive adhesive according to claim 8, which is cut so that the absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate. It is in the polarizing plate.

The other twelfth aspect is
12. The polarizing plate with an adhesive according to claim 8, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS.

The other thirteenth aspect is
It exists in the design method of the polarizing plate with an adhesive which designs so that light leakage may be improved by reducing the distribution of the absorption axis after the durability test of the polarizing plate with an adhesive bonded on the glass substrate.

The other fourteenth aspect is
To improve light leakage so that the distribution of the absorption axis after a heat resistance test at 80 ° C. for 7 days of the pressure-sensitive adhesive polarizing plate bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. It is in the design method of the polarizing plate with an adhesive to design.

The other fifteenth aspect is
Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. It is in the design method of the polarizing plate with an adhesive.

The other sixteenth aspect is
16. The method for designing a polarizing plate with an adhesive according to any one of claims 13 to 15, wherein the gel content of the adhesive is 0.1% or more and 40% or less.

The other seventeenth aspect is
16. The method for designing a polarizing plate with an adhesive according to claim 13, wherein the gel content of the adhesive is 80% or more and 99% or less.

The other eighteenth aspect is
18. The method for designing a polarizing plate with an adhesive according to claim 13, wherein the polarizing plate is a polarizing plate for WV.

The other nineteenth aspect is
The pressure-sensitive adhesive polarizing plate according to any one of claims 13 to 18, wherein the polarization degree distribution after a heat resistance test at 80 ° C for 7 days after being attached to a glass substrate is not more than 0.2 in terms of a triple value of the standard deviation. It is in the design method.

The other 20th aspect is
To improve light leakage so that the distribution of the absorption axis after the heat resistance test at 80 ° C. for 7 days of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. It is in the design method of the polarizing plate with an adhesive to design.

The other 21st aspect is
21. The method of designing a polarizing plate with an adhesive according to claim 20, wherein the distribution of the degree of polarization after being bonded to a glass substrate and subjected to a heat test at 80 ° C. for 7 days is 0.2 or less in terms of a triple value of the standard deviation.

The other 22nd aspect is
22. The method for designing a polarizing plate with an adhesive according to claim 20 or 21, wherein the absolute value of the inherent birefringence value of the adhesive is 4 × 10 ⁻⁴ or less.

The other 23rd aspect is
23. The pressure-sensitive adhesive according to any one of claims 20 to 22, which is cut so that an absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate. It exists in the design method of a polarizing plate.

The other 24th aspect is
24. The method for designing a polarizing plate with an adhesive according to claim 20, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS.

The other 25th aspect is
It exists in the design method of the polarizing plate with an adhesive which designs so that the distribution of the absorption axis of an polarizing plate with an adhesive may be made small.

The other 26th aspect is
26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the gel content of the adhesive is adjusted.

The other 27th aspect is
26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the position of light leakage is specified from the distribution of axial deviation.

The other 28th aspect is
26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the polarizing plate with an adhesive is a polarizing plate with an adhesive retardation layer.

The other 29th aspect is
The polarizing plate with a retardation layer is formed by coating a retardation layer by coating a liquid crystal material on a transparent protective film, or by separately forming a retardation layer formed by coating a liquid crystal material on the transparent protective film. 29. The method for designing a polarizing plate with an adhesive retardation layer according to claim 28, wherein the polarizing plate is provided by transfer and the transparent protective film and the retardation layer are integrated.

The other 30th aspect is
30. The method for designing a polarizing plate with an adhesive retardation layer according to claim 29, wherein the retardation layer has a tilted alignment layer of a discotic liquid crystal fixed thereto.

The other 31st aspect is
A liquid crystal panel manufacturing method using the pressure-sensitive adhesive plate designed by the method for designing a pressure-sensitive adhesive plate according to any one of claims 13 to 30.

The other thirty-second aspect is
A deflection plate manufacturing method using the pressure-sensitive adhesive plate designed by the pressure-sensitive adhesive plate designing method according to any one of claims 13 to 30.

The other 33rd aspect is
It exists in the manufacturing method of the polarizing plate with an adhesive which suppresses light leakage by making the distribution of the axial shift of the absorption axis of a polarizing plate with an adhesive small.

Claims (33)

A polarizing plate with an adhesive designed to improve light leakage by reducing the distribution of the absorption axis after the durability test of the polarizing plate with an adhesive bonded to a glass substrate. To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with the adhesive bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. Designed polarizing plate with adhesive. Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. The polarizing plate with an adhesive. 4. The polarizing plate with an adhesive according to claim 1, wherein the gel content of the adhesive is 0.1% or more and 40% or less. The polarizing plate with an adhesive according to any one of claims 1 to 3, wherein a gel content of the adhesive is 80% or more and 99% or less. 6. The polarizing plate with an adhesive according to claim 1, wherein the polarizing plate is a polarizing plate for WV. The polarizing plate with the pressure-sensitive adhesive according to any one of claims 1 to 6, wherein the polarization degree distribution after being bonded to a glass substrate and subjected to a heat test at 80 ° C for 7 days is 0.2 or less in terms of three times the standard deviation. To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. Designed polarizing plate with adhesive. 9. The polarizing plate with an adhesive according to claim 8, wherein the polarization degree distribution after the heat resistance test at 80 ° C. for 7 days after being attached to a glass substrate is 0.2 or less in terms of a triple value of the standard deviation. 10. The polarizing plate with the pressure-sensitive adhesive according to claim 8, wherein an absolute value of the pressure-sensitive adhesive intrinsic birefringence of the pressure-sensitive adhesive is 4 × 10 ⁻⁴ or less. 11. The pressure-sensitive adhesive according to claim 8, which is cut so that the absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate. Polarizer. 12. The polarizing plate with an adhesive according to claim 8, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS. A method for designing a polarizing plate with an adhesive, which is designed to improve light leakage by reducing the distribution of absorption axes after a durability test of the polarizing plate with an adhesive bonded to a glass substrate. To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with the adhesive bonded to the glass substrate is 1.3 degrees or less, which is three times the standard deviation. How to design a polarizing plate with adhesive. Designed to improve light leakage so that the difference between the maximum and minimum values of the absorption axis of a polarizing plate with adhesive bonded to a glass substrate after a heat test at 80 ° C for 7 days is 1.5 degrees or less. To design a polarizing plate with adhesive. 16. The method for designing a polarizing plate with an adhesive according to any one of claims 13 to 15, wherein the gel content of the adhesive is 0.1% to 40%. 16. The method for designing a polarizing plate with an adhesive according to claim 13, wherein the gel content of the adhesive is 80% or more and 99% or less. 18. The method for designing a polarizing plate with an adhesive according to claim 13, wherein the polarizing plate is a polarizing plate for WV. The pressure-sensitive adhesive polarizing plate according to any one of claims 13 to 18, wherein the polarization degree distribution after a heat resistance test at 80 ° C for 7 days after being attached to a glass substrate is not more than 0.2 in terms of a triple value of the standard deviation. Design method. To improve light leakage so that the distribution of the absorption axis after the heat resistance test after 7 days at 80 ° C. of the polarizing plate with adhesive bonded to the glass substrate is not more than 0.2 degrees at 3 times the standard deviation. How to design a polarizing plate with adhesive. 21. The method for designing a polarizing plate with an adhesive according to claim 20, wherein the distribution of the degree of polarization after being bonded to a glass substrate and subjected to a heat test at 80 ° C. for 7 days is 0.2 or less in terms of a triple value of the standard deviation. 22. The method for designing a polarizing plate with an adhesive according to claim 20 or 21, wherein an absolute value of the adhesive's intrinsic birefringence of the adhesive is 4 × 10 ⁻⁴ or less. 23. The pressure-sensitive adhesive according to any one of claims 20 to 22, which is cut so that an absorption axis of the polarizing plate is within 90 ± 0.5 degrees or within 0 ± 0.5 degrees with respect to the side of the polarizing plate. A method of designing a polarizing plate. 24. The method for designing a polarizing plate with an adhesive according to claim 20, wherein the polarizing plate is a polarizing plate for VA or a polarizing plate for IPS. A method for designing a polarizing plate with an adhesive, which is designed so as to reduce the distribution of the absorption axis of the polarizing plate with an adhesive. 26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the gel content of the adhesive is adjusted. 26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the position of light leakage is specified from the distribution of axial deviation. 26. The method for designing a polarizing plate with an adhesive according to claim 25, wherein the polarizing plate with an adhesive is a polarizing plate with an adhesive retardation layer. The polarizing plate with a retardation layer is formed by coating a retardation layer by coating a liquid crystal material on a transparent protective film, or by separately forming a retardation layer formed by coating a liquid crystal material on the transparent protective film. 29. The method for designing a polarizing plate with an adhesive retardation layer according to claim 28, wherein the transparent protective film and the retardation layer are integrated by transfer. 30. The method for designing a polarizing plate with an adhesive retardation layer according to claim 29, wherein the retardation layer fixes a tilted alignment layer of a discotic liquid crystal. 31. A method for producing a liquid crystal panel, wherein the pressure-sensitive adhesive polarizing plate designed by the method for designing a pressure-sensitive adhesive polarizing plate according to claim 13 is used. A method for producing a polarizing plate using the polarizing plate with an adhesive designed by the method for designing a polarizing plate with an adhesive according to any one of claims 13 to 30. The manufacturing method of the polarizing plate with an adhesive which suppresses light leakage by making the distribution of the axial shift of the absorption axis of the polarizing plate with an adhesive small.