JPH06289221A - Production of elliptically polarizing plate - Google Patents

Abstract

PURPOSE:To obtain excellent mass productivity without deterioration of optical characteristics by laminating a linearly polarizing plate and a phase plate while considering the optical axes relating to each other and then cutting the laminated body. CONSTITUTION:A linearly polarizing plate 1 laminated with a protective film on the surface is cut in bias considering the optical axes relating to the phase plate to be laminated. The cut plates are joined to form a roll film by a proper means. Then the protective film on one surface of the linearly polarizing plate 1 is peeled. The plate 1 is treated to have cohesive property on the peeled surface and then wound on an exclusive drum. Then a release film is peeled and the bias-cut cohesive linearly polarizing plate 1 is continuously laminated with an uniaxialy oriented phase plate in a roll film state. The laminated body is wound on an exclusive drum to obtain the non-cohesive elliptically polarizing plate wound on the drum. This continuous noncohesive elliptically polarizing plate is treated to have cohesion property, and then a bias-cut cohesive elliptically polarizing plate in a sheet is obtd. This large-size bias cohesive elliptically polarizing plate is cut into chips of elliptically polarizing plate of proper size corresponding to a liquid crystal display panel.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an elliptically polarizing plate used in a liquid crystal display panel.

[0002]

2. Description of the Related Art The basic structure of a liquid crystal display panel is as shown in FIG.
The linear polarizing plates 22 are arranged on both sides of the liquid crystal cell 21, and the liquid crystal cell 21 includes two substrates 24 on which a transparent electrode layer 23 is formed.
Are arranged opposite to each other via a spacer 25, and the liquid crystal is provided between both substrates 24.
It has a structure in which 26 is enclosed and the periphery is completely sealed (reference numeral 27 is a pressure-sensitive adhesive).

The substrate 24 is required to be optically transparent and optically isotropic, and a glass plate has been used exclusively in the past, but recently, an engineering plastic film has been used as a typical application such as multimedia. Substrates made of metal are also being used.

Liquid crystal display panels are used in large quantities as display devices for office automation equipment and the like, and in particular, STN (Super Twisted, Nematic) type liquid crystal display panels are often used for large liquid crystal display panels. Recently, STN type liquid crystal display panels are often used for medium and small size display panels.

Since the STN liquid crystal display panel utilizes birefringence, the light passing through the liquid crystal cell becomes elliptically polarized light, and the visible display color is colored in a blue system or a green or yellow system. Therefore, in order to prevent coloring by returning elliptically polarized light to linearly polarized light, a method of interposing a retardation plate (a member having birefringence) has been proposed (a linear polarizing plate and a retardation plate are bonded together. , That is, an elliptically polarizing plate). This system is also called an FTN system, and the FTN system enables a monochrome display by a single-layer liquid crystal cell.

The conventional elliptically polarizing plate is manufactured by using a linearly polarizing plate and a retardation plate which are separately processed with an adhesive, and using a super cutter, a Thomson punching machine, etc., each having a predetermined size and an optical axis relationship. It is manufactured by cutting the chip so that it can be maintained and using a bonding machine to bond both.

However, due to the expansion of applications of the STN liquid crystal display panel, the size of the elliptical polarizing plate for making the STN liquid crystal display black and white, and the diversification of the optical axes of the polarizing plate optical axis and the retardation plate optical axis, It is not desirable from the viewpoint of yield, cost, etc. that the linearly polarizing plate and the retardation plate, which have been adhesively processed, are separately cut into chips and are bonded, and the material cannot be effectively used. There is a problem.

An object of the present invention is to provide a method for manufacturing an elliptically polarizing plate which solves the above drawbacks.

[0009]

The gist of the present invention will be described with reference to the accompanying drawings.

The elliptically polarized light is characterized in that the linearly polarizing plate 1 and the retardation plate 2 are each formed in the shape of a roll film, the two are bonded together in consideration of their optical axes of relation, and then cut into a predetermined shape. The present invention relates to a method for manufacturing a plate.

[0011]

The method of forming the linearly polarizing plate 1 and the retardation film 2 in the form of a roll film, laminating the two in consideration of their relational optical axes, and then cutting them into a predetermined shape, that is, forming and adhering separately This is a method in which the processed linearly polarizing plate 1 and the retardation plate 2 are not bonded to each other in consideration of the related optical axis in each case, but are cut in a predetermined shape after being bonded in consideration of the related optical axis in advance. Therefore, the mass productivity is excellent and the optical characteristics are not deteriorated.

[0012]

EXAMPLE A large elliptically polarizing plate is manufactured by using the coating machine for laminating the linear polarizing plate 1 and the retardation plate 2 by the following steps.

A linear polarizing plate 1 having protective films attached on both sides is illustrated in FIG. 2 in consideration of an optical axis (a light absorption axis in a direction of an arrow in FIG. 2) with a retardation plate 2 to be attached. Bias cut as shown in FIG. 2 (L line is a cut line), and then the linear polarizing plate 1 cut as shown in FIG. 3 is spliced by an appropriate means (such as an adhesive tape 5) to form a roll film. (The direction of the arrow in FIG. 3 is the light absorption axis) and the protective film on one side of the linear polarizing plate 1 is peeled off,
Adhesive processing is applied to this surface (the continuous bias adhesive linearly polarizing plate 1 having a release film attached thereto) is wound on a dedicated drum.

The release film is peeled off, and the continuous bias adhesive linearly polarizing plate 1 and the roll film-shaped uniaxially stretched retardation plate 2 are continuously bonded and wound on a dedicated drum and wound on a dedicated drum. Obtain a rotated non-adhesive elliptically polarizing plate.

This non-adhesive elliptically polarizing plate (on the side of the uniaxially stretched retardation plate 2) is continuously subjected to adhesive processing (with a release film) to obtain a sheet-shaped bias adhesive elliptically polarizing plate. This large size bias adhesive elliptically polarizing plate can be used for small, medium and
A chip-shaped elliptically polarizing plate corresponding to a large-sized, appropriately sized liquid crystal display panel.

In use, the release film of the chip-shaped elliptically polarizing plate is peeled off, and the elliptically polarizing plate is attached to both sides (or one side) of the liquid crystal cell 3 as shown in FIG. 4 (reference numeral 4). Is a pressure sensitive adhesive, and the liquid crystal cell 3
Has the same configuration as in FIG. ). Of course, the protective film attached to the elliptically polarizing plate is also peeled off.

By the means described above, small, medium and large chip-shaped elliptically polarizing plates used for various liquid crystal display panels can be efficiently manufactured at low cost.

As the type of the retardation plate 2, a polyvinyl alcohol-based resin or the like is generally used, but other uniaxially stretched films may be used, and all uniaxially stretched retardation plates 2 may be used.
Can be used.

Retardation (Re) is an important physical property value of the retardation plate 2. This physical property value is Re =
It is a physical quantity defined by Δnd (Δn: birefringence, d: film thickness).

When the roll film-shaped retardation plate 2 is bonded to the linear polarizing plate 1, the roll film-shaped retardation plate 2 is pulled out from a dedicated drum, but it is bonded by the photoelastic constant determined by the material of the film. By finding the change in retardation of the roll film-shaped retardation plate 2 before and setting the retardation value of the roll film-shaped retardation plate 2 to be used in advance to a lower value, the desired retardation can be obtained. It is possible to constantly manufacture a large elliptically polarizing plate having a retardation value.

Specific examples will be described below.

Example 1 500 m with a unit average transmittance of 44%
Using an m-width linear polarizing plate and a roll film-shaped uniaxially stretched retardation plate 2 made of polycarbonate with a retardation value of 580 nm and 340 mm width, through the above steps, 480 × 550 mm (optical axis of retardation plate 2 The variation distribution of the retardation value of the large elliptically polarizing plate (40 °: below the sticking surface) was as follows (Fig. 5).
(See, x in FIG. 5 is the optical absorption axis of the linear polarizing plate 1, and y is the optical axis of the uniaxially stretched retardation plate 2.)

[0023]

[Table 1]

* ₁ Range means the value of (Max-Min).

* _{2 The} number of n means that one large elliptically polarizing plate or the in-plane of the uniaxially stretched retardation plate 2 is divided into n and the Re value is measured. Therefore, the upper row of the above table is the Re value of the uniaxially stretched retardation plate 2 divided into 100 pieces before bonding, and the lower row is 1
This shows the Re value of the large elliptically polarizing plate divided into 60 pieces.

Example 2 Using the same linear polarizing plate 1 as in Example (1), a retardation value was obtained by using a uniaxially stretched retardation plate 2 made of polyvinyl alcohol in the form of a roll film having a retardation value of 406 nm and a width of 630 mm. The distribution of variation in value was as follows (the rest was the same as in Example (1)).

[0027]

[Table 2]

[0028]

EFFECTS OF THE INVENTION The method for producing an elliptically polarizing plate according to the present invention makes it possible to produce an epoch-making elliptically polarizing plate with uniform optical properties, excellent mass productivity, and compact liquid crystal display device.
Good yield for medium and large size, especially small and medium size
It enables stable supply of (clock size, toy size) elliptically polarizing plates.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a liquid crystal display panel.

FIG. 2 is a process description of the present embodiment.

FIG. 3 is a process description of the present embodiment.

FIG. 4 is an explanatory cross-sectional view showing a usage state of a product manufactured according to this example.

FIG. 5 is an explanatory diagram below a pasting surface of the elliptically polarizing plate according to the present embodiment.

[Explanation of symbols]

 1 Linear polarization plate 2 Phase difference plate

─────────────────────────────────────────────────── ───

[Procedure amendment]

[Submission date] June 17, 1993

[Procedure Amendment 1]

[Document name to be amended] Statement

[Correction target item name] Full text

[Correction method] Change

[Correction content]

[Document name] Statement

Title of the invention: Method for manufacturing elliptically polarizing plate

[Claims]

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an elliptically polarizing plate used in a liquid crystal display panel.

[0002]

2. Description of the Related Art The basic structure of a liquid crystal display panel is as shown in FIG.
The linear polarizing plates 22 are arranged on both sides of the liquid crystal cell 21, and the liquid crystal cell 21 includes two substrates 24 having a transparent electrode layer 23 formed thereon.
Are placed opposite to each other via a spacer 25, and the liquid crystal is placed between both substrates 24.
It has a structure in which 26 is enclosed and the periphery is completely sealed (reference numeral 27 is a pressure-sensitive adhesive).

The substrate 24 is required to be optically transparent and optically isotropic, and a glass plate has been used exclusively in the past, but recently, an engineering plastic film has been used as a typical application such as multimedia. Substrates made of metal are also being used.

Liquid crystal display panels are used in large quantities as display devices for office automation equipment and the like, and in particular, STN (Super Twisted, Nematic) type liquid crystal display panels are often used for large liquid crystal display panels. Recently, STN type liquid crystal display panels are often used for medium and small size display panels.

Since the STN liquid crystal display panel utilizes birefringence, the light passing through the liquid crystal cell becomes elliptically polarized light, and the visible display color is colored in a blue system or a green or yellow system. Therefore, in order to prevent coloring by returning elliptically polarized light to linearly polarized light, a method of interposing a retardation plate (a member having birefringence) has been proposed (a linear polarizing plate and a retardation plate are bonded together. , That is, an elliptically polarizing plate). This system is also called an FTN system, and the FTN system enables a monochrome display by a single-layer liquid crystal cell.

The conventional elliptically polarizing plate is manufactured by using a linearly polarizing plate and a retardation plate which are separately adhered to each other, and using a super cutter, a Thomson punching machine, etc., each having a predetermined size and an optical axis relationship. It is manufactured by cutting the chip so that it can be maintained and using a bonding machine to bond both.

However, due to the expansion of applications of STN liquid crystal display panels, the size of the elliptical polarizing plate for making STN liquid crystal display black and white, the relationship between the polarizing plate optical axis and the retardation plate optical axis, and the diversification of the optical axis, If the adhesive-processed linearly polarizing plate and retardation plate were separately cut into chips and bonded, it is not desirable from the viewpoint of yield, cost, etc., and the material cannot be used effectively. The problem has arisen.

An object of the present invention is to provide a method for manufacturing an elliptically polarizing plate which solves the above drawbacks.

[0009]

The gist of the present invention will be described with reference to the accompanying drawings.

The elliptically polarized light is characterized in that the linearly polarizing plate 1 and the retardation plate 2 are each formed in the shape of a roll film, the two are bonded together in consideration of their optical axes of relation, and then cut into a predetermined shape. The present invention relates to a method for manufacturing a plate.

[0011]

The method of forming the linearly polarizing plate 1 and the retardation film 2 in the form of a roll film, laminating the two in consideration of their relational optical axes, and then cutting them into a predetermined shape, that is, forming and adhering separately This is a method in which the processed linearly polarizing plate 1 and the retardation plate 2 are not bonded to each other in consideration of the related optical axis in each case, but are cut in a predetermined shape after being bonded in consideration of the related optical axis in advance. Therefore, the mass productivity is excellent and the optical characteristics are not deteriorated.

[0012]

EXAMPLE A large elliptically polarizing plate is manufactured by using the coating machine for laminating the linear polarizing plate 1 and the retardation plate 2 by the following steps.

A linear polarizing plate 1 having protective films attached on both sides is illustrated in FIG. 2 in consideration of an optical axis (a light absorption axis in a direction of an arrow in FIG. 2) with a retardation plate 2 to be attached. Bias cut as shown in FIG. 2 (L line is a cut line), and then the linear polarizing plate 1 cut as shown in FIG. 3 is spliced by an appropriate means (such as an adhesive tape 5) to form a roll film. (The direction of the arrow in FIG. 3 is the light absorption axis) and the protective film on one side of the linear polarizing plate 1 is peeled off,
Adhesive processing is applied to this surface (the continuous bias adhesive linearly polarizing plate 1 having a release film attached thereto) is wound on a dedicated drum.

The release film is peeled off, and the continuous bias adhesive linearly polarizing plate 1 and the roll film-shaped uniaxially stretched retardation plate 2 are continuously bonded and wound on a dedicated drum and wound on a dedicated drum. A non-adhesive elliptical polarizing plate is obtained.

This non-adhesive elliptically polarizing plate (on the side of the uniaxially stretched retardation plate 2) is continuously subjected to adhesive processing (with a release film) to obtain a sheet-shaped bias adhesive elliptically polarizing plate. This large size bias adhesive elliptically polarizing plate can be used for small, medium and
A chip-shaped elliptically polarizing plate corresponding to a large-sized, appropriately sized liquid crystal display panel.

In use, the release film of the chip-shaped elliptically polarizing plate is peeled off, and the elliptically polarizing plate is attached to both sides (or one side) of the liquid crystal cell 3 as shown in FIG. 4 (reference numeral 4). Is a pressure sensitive adhesive, and the liquid crystal cell 3
Has the same configuration as in FIG. ). Of course, the protective film attached to the elliptically polarizing plate is also peeled off.

By the means described above, small, medium and large chip-shaped elliptically polarizing plates used for various liquid crystal display panels can be efficiently manufactured at low cost.

As the type of the retardation plate 2, a polyvinyl alcohol-based resin or the like is generally used, but other uniaxially stretched films may be used, and all uniaxially stretched retardation plates 2 may be used.
Can be used.

Retardation (Re) is an important physical property value of the retardation plate 2. This physical property value is Re =
It is a physical quantity defined by Δnd (Δn: birefringence, d: film thickness).

When the roll film-shaped retardation plate 2 is bonded to the linear polarizing plate 1, the roll film-shaped retardation plate 2 is pulled out from a dedicated drum, but it is bonded by the photoelastic constant determined by the material of the film. By finding the change in retardation of the roll film-shaped retardation plate 2 before and setting the retardation value of the roll film-shaped retardation plate 2 to be used in advance to a lower value, the desired retardation can be obtained. It is possible to constantly manufacture a large elliptically polarizing plate having a retardation value.

Specific examples will be described below.

<Embodiment 1> 500 m with a single average transmittance of 44%
Using an m-width linearly polarizing plate and a roll film-shaped uniaxially stretched retardation plate 2 in the form of a roll film having a retardation value of 580 nm and 340 mm, 480 × 550 mm (optical axis of retardation plate 2 \ 40 ° The distribution of variation in retardation value of the large-sized elliptically polarizing plate (below the bonding surface) was as follows (Fig. 5).
(See, x in FIG. 5 is the optical absorption axis of the linear polarizing plate 1, and y is the optical axis of the uniaxially stretched retardation plate 2.)

[0023]

[Table 1]

* ₁ Range means the value of (Max-Min).

* _{2 The} number of n means that one large elliptically polarizing plate or the in-plane of the uniaxially stretched retardation plate 2 is divided into n and the Re value is measured. Therefore, the upper row of the above table is the Re value of the uniaxially stretched retardation plate 2 divided into 100 pieces before bonding, and the lower row is 1
This shows the Re value of the large elliptically polarizing plate divided into 60 pieces.

Example 2 Using the same linear polarizing plate 1 as in Example (1), a retardation value was obtained by using a uniaxially stretched retardation plate 2 made of polyvinyl alcohol in the form of a roll film having a retardation value of 406 nm and a width of 630 mm. The distribution of variation in values was as follows (others were the same as in Example (1)).

[0027]

[Table 2]

[0028]

EFFECTS OF THE INVENTION The method for producing an elliptically polarizing plate according to the present invention makes it possible to produce an epoch-making elliptically polarizing plate with uniform optical properties, excellent mass productivity, and compact liquid crystal display device.
Good yield for medium and large size, especially small and medium size
It enables stable supply of (clock size, toy size) elliptically polarizing plates.

[Brief description of drawings]

FIG. 1 is an explanatory cross-sectional view of a liquid crystal display panel.

FIG. 2 is a process description of the present embodiment.

FIG. 3 is a process description of the present embodiment.

FIG. 4 is an explanatory cross-sectional view showing a usage state of a product manufactured according to this example.

FIG. 5 is an explanatory diagram below a pasting surface of the elliptically polarizing plate according to the present embodiment.

[Explanation of reference numerals] 1 linear polarizing plate 2 retardation plate

[Procedure Amendment 2]

[Document name to be corrected] Drawing

[Name of item to be corrected] Figure 1

[Correction method] Change

[Correction content]

[Figure 1]

Claims (1)

[Claims] 1. An elliptically polarized light characterized in that a linearly polarizing plate and a retardation film are formed in a roll film shape, respectively, and the two are bonded together in consideration of their relational optical axes and then cut into a predetermined shape. Method of manufacturing a plate.