JPH11160537A - Polarizing plate for liquid crystal display element and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the polarizing plate for a liquid crystal display element with excellent dampproofing and the manufacturing method capable of obtaining the polarizing plate efficiently. SOLUTION: The polarizing plate is equipped with at least one polarizing plate main body 2 which has a polarizing function and a dampproof layer 4 provided on at least one exposed end surface of the polarizing plate main body 2. Further, a laminated body is formed by stacking polarizing plate main bodies 2 having the polarizing function and while the laminated body is rotated on an axis perpendicular to the main surface of the polarizing plate main bodies 2, dampproof layers 4 are formed on the end surfaces of the polarizing plate main bodies 2.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a polarizing plate provided on a substrate of a liquid crystal display device and a method for manufacturing the same.

[0002]

2. Description of the Related Art Some liquid crystal display devices have a polarizing plate on a substrate for use as a light receiving device. This polarizing plate has, for example, the configuration shown in FIG. That is, this polarizing plate is mainly composed of polarizing plate bodies 11 and 12 which are plate-like bodies, and a resin layer 13 such as a polyvinyl alcohol layer sandwiched between the polarizing plate bodies 11 and 12.

Usually, when manufacturing this polarizing plate, large-sized polarizing plate bodies 11 and 12 are bonded together with an adhesive layer 13 and then adjusted to the size of the screen of a liquid crystal display device (hereinafter abbreviated as LCD). And cut it.

[0004]

However, in the polarizing plate having the above structure, since no treatment is applied to the cut surface, moisture is absorbed from the cut surface of the polarizing plate during a long-term use, so that moisture is generated inside the polarizing plate. , Causing bleeding or the like inside the polarizing plate, which causes a problem in reliability. In particular, in a high-temperature and high-humidity test, which is a reliability test, bleeding inside the polarizing plate appears remarkably.

[0005] In addition, there has not been an appropriate treatment method for preventing moisture from penetrating from the cut surface of the polarizing plate, so that a polarizing plate capable of preventing moisture penetration can be obtained efficiently. Is desired.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a polarizing plate for a liquid crystal display device having excellent moisture proof properties and a method for manufacturing a polarizing plate capable of efficiently obtaining the polarizing plate. And

[0007]

Means for Solving the Problems In order to solve the above problems, the present invention has taken the following means. The present invention relates to a polarizing plate provided on a substrate of a liquid crystal display element, wherein at least one polarizing plate body having a polarizing function and a moisture-proof layer provided on at least one exposed end face of the polarizing plate body And a polarizing plate for a liquid crystal display element, comprising:

According to this configuration, since the moisture-proof layer is provided on the cut surface of the polarizing plate, it is possible to sufficiently prevent moisture from penetrating into the inside of the polarizing plate due to moisture absorption from the cut surface of the polarizing plate. Thereby, the reliability of the polarizing plate can be improved.

In the polarizing plate for a liquid crystal display element of the present invention, it is preferable that the polarizing plate body is constituted by a pair of polarizing substrates and an adhesive layer sandwiched between the polarizing substrates.

[0010] In the polarizing plate for a liquid crystal display device of the present invention, the moisture-proof layer preferably has a thickness of 50 to 100 nm. Thereby, a sufficient moisture-proof effect can be exhibited with a minimum thickness.

The present invention also relates to a method of manufacturing a polarizing plate provided on a substrate of a liquid crystal display device, comprising the steps of: stacking a plurality of polarizing plate bodies having a polarizing function to form a laminate; Forming a moisture-proof layer on the end face of the polarizing plate body while rotating the laminate around an axis perpendicular to the main surface of the plate body. And a method for producing the same.

According to this configuration, the moisture-proof layer can be easily formed on the cut surface of the rectangular LCD polarizing plate,
The polarizing plate can be obtained efficiently. FIG. 1 is a cross-sectional view illustrating a polarizing plate for a liquid crystal display element according to an embodiment of the present invention.

[0013]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a sectional view showing a polarizing plate for a liquid crystal display device according to one embodiment of the present invention. Reference numerals 1 and 2 in the figure denote polarizing plate bodies which are plate-like bodies made of a polyester film or the like. An adhesive layer 3 made of a polyvinyl alcohol layer or the like is sandwiched between the polarizing plate bodies 1 and 2. Further, a moisture-proof layer 4 is provided on the end faces of the polarizing plate bodies 1 and 2.

As a material of the moisture-proof layer 4, SiO ₂ , Si ₃ N ₄ , diamond carbon (hereinafter, DLC) and the like can be exemplified in consideration of moisture-proof property and ease of formation.
The thickness of the moisture-proof layer 4 is preferably 50 to 100 nm in consideration of sufficient moisture-proof property and formation efficiency.

Next, an example of a method for manufacturing the polarizing plate will be described with reference to FIG. First, two polarizing plate bodies are bonded with an adhesive material such as polyvinyl alcohol.
This polarizing plate is cut to the size of the LCD screen.

A plurality of the polarizing plates 8 thus obtained are stacked so that their main surfaces are overlapped to form a laminate. The polarizing plates 8 at both ends of the laminate of the polarizing plates 8 are pressed from outside by a pair of pressing plates 7.

Next, the laminate is set on a deposition apparatus such as a sputtering apparatus or a plasma CVD apparatus. That is, as shown in FIG. 2, the first electrode 5 and the second electrode 6
The laminated body of the polarizing plate 8 is placed between the two. At this time, the laminate is arranged such that the end face of the polarizing plate 8 faces the first and second electrodes 5 and 6. When the deposition device is a sputtering device, the second electrode 6 is used as a target.

Next, while rotating the laminate around a rotation axis 9 perpendicular to the main surface of the polarizing plate (polarizing plate body) 8,
SiO ₂ , Si ₃ N ₄ , and DLC are applied on the end face of the polarizing plate 8 to form the moisture-proof layer 4. Since the moisture-proof layer 4 is formed on the end face of the polarizing plate 8 in this manner, the moisture-proof layer 4 can be efficiently formed on the end face of the rectangular polarizing plate 8 where film formation is relatively difficult.

After the moisture-proof layer 4 is formed, the laminate is removed from the deposition apparatus, the holding plate 7 is removed from the laminate, and the polarizing plates 8 are separated one by one.

Next, an embodiment performed to clarify the effects of the present invention will be described. First, the moisture-proof property of the moisture-proof layer in the present invention will be examined. 25μ thickness as substrate
A polyester film (PET) having a thickness of 100 m and a moisture-proof layer having a thickness of 100 nm was provided thereon by sputtering to prepare a sample.
The water vapor transmission rate was evaluated by a cup method based on JIS. The results are shown in Table 1 below.

The sample was made of SiO ₂ , S as a moisture-proof layer.
i ₃ N ₄ and DLC were applied. Also,
For comparison, an untreated polyester film was also evaluated.

[0022]

[Table 1]

As is clear from Table 1, the moisture-proof layer was made of S
Those coated with iO ₂ , Si ₃ N ₄ , and DLC
All exhibited a great moisture-proof effect. On the other hand, PET without the moisture-proof layer had a very high degree of moisture absorption.

Next, a thickness of 1 was formed on the four end faces of the polarizing plate obtained by laminating two polarizing plate bodies with a polyvinyl alcohol layer.
A 00 nm moisture-proof layer was formed using the apparatus shown in FIG.
This polarizing plate was left under high-temperature and high-quality conditions of 85 ° C. and 85% RH, and the polarizing plate was evaluated. The results are shown in Table 2 below. The evaluation was made based on the presence or absence of bleeding around the polarizing plate. For comparison, an untreated polarizing plate was also evaluated.

[0025]

[Table 2]

As is clear from Table 2, the polarizing plate having SiO ₂ , Si ₃ N ₄ , and DLC deposited on the end face as a moisture-proof layer exhibits a moisture-proof effect for a long time even under high temperature and high quality conditions. did. On the other hand, when the polarizing plate is not provided with a moisture-proof layer on the end face, it is 100 hours under high temperature and high quality conditions.
Bleeding was confirmed.

In the above embodiment, the moisture-proof layer is formed by an LCD.
Although the case where it is provided on the end face of the polarizing plate for is described,
The present invention can be applied to, for example, a bare chip or the like in which it is difficult to form a layer on an end face.

[0028]

As described above, the polarizing plate for a liquid crystal display device of the present invention has a moisture-proof layer provided on the cut surface of the polarizing plate, so that moisture is absorbed inside the polarizing plate by absorbing moisture from the cut surface of the polarizing plate. Penetration can be sufficiently prevented. Thereby, the moisture resistance of the polarizing plate can be improved, and the reliability can be improved.

Further, in the method of manufacturing a polarizing plate for a liquid crystal display element according to the present invention, a plurality of polarizing plate bodies having a polarizing function are laminated to form a laminate, and the laminated body is formed around an axis perpendicular to the main surface of the polarizing plate body. Since the moisture-proof layer is formed on the end face of the polarizing plate body while rotating the laminate, a polarizing plate for a liquid crystal display element having excellent moisture-proof properties can be obtained efficiently.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a polarizing plate for a liquid crystal display device according to one embodiment of the present invention.

FIG. 2 is a schematic view for explaining a method for manufacturing a liquid crystal display element of the present invention.

FIG. 3 is a cross-sectional view showing a conventional polarizing plate for a liquid crystal display element.

[Explanation of symbols]

1, 2 ... polarizing plate body, 3 ... adhesive layer, 4 ... moisture-proof layer, 5 ... first electrode, 6 ... second electrode, 7 ... holding plate, 8 ... polarizing plate,
9 ... Rotary axis.

Claims (4)

[Claims] 1. A polarizing plate provided on a substrate of a liquid crystal display element, comprising: at least one polarizing plate body having a polarizing function; and moisture proof provided on at least one exposed end face of the polarizing plate body. A polarizing plate for a liquid crystal display device, comprising: 2. The polarizing plate body comprises: a pair of polarizing substrates;
2. The polarizing plate for a liquid crystal display device according to claim 1, comprising: an adhesive layer sandwiched between the polarizing substrates. 3. The polarizing plate for a liquid crystal display device according to claim 1, wherein the moisture-proof layer has a thickness of 50 to 100 nm. 4. A method for manufacturing a polarizing plate provided on a substrate of a liquid crystal display element, comprising: laminating a plurality of polarizing plate bodies having a polarizing function to form a laminate; Forming a moisture-proof layer on the end face of the polarizing plate body while rotating the laminate around an axis perpendicular to the plane. A method for manufacturing a polarizing plate for a liquid crystal display element.