TWI661217B - Polarizing plate and method for manufacturing liquid crystal panel - Google Patents

Abstract

The invention discloses a polarizing plate protective layer that protects a polarizing plate layer and has a single layer, which can suppress a decrease in manufacturing efficiency of a liquid crystal panel and a method for manufacturing a liquid crystal panel. The polarizing plate 10 according to one embodiment is a polarizing plate including a polarizer layer 11 that selectively passes light polarized in a predetermined direction. The polarizing plate includes: a polarizing plate body 13 on which a polarizing plate protective layer 12 for protecting the polarizing plate layer is laminated on a polarizing plate layer; a protective film 14 laminated on the polarizing plate protective layer; and a polarizing plate layer The adhesive layer 15 on the opposite side of the polarizer protective layer. The bending resistance of the polarizing plate 10A composed of an adhesive layer, a polarizing plate body, and a protective film is 7.6 mN or more.

Description

Polarizing plate and method for manufacturing liquid crystal panel

The invention relates to a method for manufacturing a polarizing plate and a liquid crystal panel.

As disclosed in Patent Document 1, there is known a polarizing plate used in a liquid crystal panel, which includes a polarizer layer that transmits light polarized in a predetermined direction, and two polarizer protective layers provided on the polarizer layer. On both sides to protect the polarizer layer. A liquid crystal panel is manufactured by bonding the above-mentioned polarizing plate to a liquid crystal cell. When the polarizing plate is attached to the liquid crystal cell, the polarizing plate is held by a holding device such as a suction disk, and the polarizing plate is aligned with the liquid crystal cell while the holding device is moved. Therefore, if the polarizing plate is to be correctly positioned in the liquid crystal cell, the polarizing plate must be aligned with the holding device. Therefore, for example, an L-shaped alignment bar is pressed against the polarizing plate held by the holding device, and the inner surface of the alignment bar (the surface abutting the polarizing plate) is used as a reference plane to polarize the polarizing plate. The position (or direction) of is adjusted relative to the holding device.

[Prior technical literature] [Patent Literature]

Patent Document 1: Japanese Patent Application Laid-Open No. 2007-292966

In recent years, there has been a demand for a polarizing plate having a structure in which a polarizer protective layer is laminated only on one side of the polarizer layer, not on both sides. When manufacturing a liquid crystal panel using a polarizing plate provided with only one polarizer protective layer with respect to the polarizer layer, in order to adjust the position of the polarizing plate with respect to the holding device, when the reference plane for position adjustment is pressed against the polarizing plate, There is a problem that the polarizing plate is dropped from the holding device and the manufacturing efficiency of the liquid crystal panel is reduced.

Therefore, an object of the present invention is to provide a polarizer protective layer that protects the polarizer layer, and a method of manufacturing a liquid crystal panel, which can suppress a decrease in manufacturing efficiency of a liquid crystal panel.

A polarizing plate according to an aspect of the present invention includes a polarizing plate layer that selectively passes light polarized in a predetermined direction. The polarizing plate includes a polarizing plate body, and the polarizing plate is laminated to protect the polarizing plate Layer of polarizer protective layer; protective film, laminated on the polarizer protective layer; and an adhesive layer provided on the opposite side of the polarizer layer from the polarizer protective layer; the adhesive layer, the polarizer body and the protective film The bending resistance (bending resistance) of the laminated body is 7.6 mN or more.

In one embodiment, the bending resistance of the laminate may be 7.64 mN or more.

In the above configuration, the protective film is attached to the polarizing plate. The body is provided with an adhesive layer on the opposite side. Therefore, when manufacturing a liquid crystal panel using the above-mentioned polarizing plate, for example, when the polarizing plate is held by a holding device from the protective film side, the polarizing plate can be bonded to the liquid crystal cell via an adhesive layer. Furthermore, since the above-mentioned laminated body including the protective film has a bending resistance of 7.6 mN or more or 7.64 mN or more, even if the polarizing plate is held by the holding device as shown in the example, the reference for position adjustment faces polarized light. The position of the polarizing plate can be adjusted by pressing the plate, and the deformation of the polarizing plate can also be suppressed, and the polarizing plate cannot be easily dropped from the holding device. Therefore, even if the polarizer protective layer that protects the polarizer layer is one layer, it is possible to suppress a decrease in manufacturing efficiency of the liquid crystal panel.

In one embodiment, the bending resistance of the polarizing plate body may be 4.0 mN or less.

In one embodiment, the bending resistance of the polarizing plate body may be 3.92 mN or less.

When the bending resistance of the polarizing plate body is 4.0 mN or less or 3.92 mN or less, the bending resistance of the laminated body including the protective film is 7.6 mN or more or 7.64 mN or less because the bending resistance of the polarizing plate body is small. The structure of the above-mentioned polarizing plate has an effect.

In one embodiment, the shape viewed from the thickness direction of the polarizing plate is rectangular. The long side of the rectangle may be 90 mm to 135 mm, and the short side of the rectangle may be 50 mm to 80 mm.

In one embodiment, the material of the protective film may be polyethylene terephthalate or polypropylene.

In one embodiment, the thickness of the protective film may be 30 μm to 90 μm.

In one embodiment, the protective film may be provided on the polarizer protective layer in a peelable manner.

In this configuration, when a polarizing plate is bonded to a liquid crystal cell to manufacture a liquid crystal panel, the protective film is easily removed after the polarizing plate is bonded to the liquid crystal cell. When the protective film is peeled off in this way, the polarizing plate body having only one polarizer protective layer is adhered to the liquid crystal cell. Therefore, in the above configuration, the thickness of the liquid crystal panel can be reduced.

According to another aspect of the present invention, in a method for manufacturing a liquid crystal panel, the liquid crystal panel is obtained by bonding a polarizing plate body to a liquid crystal cell, and the polarizing plate body is polarized light that selectively passes light that is polarized in a predetermined direction. A polarizer protective layer for protecting the polarizer layer is laminated on the sheet layer. The method for manufacturing the liquid crystal panel includes a state in which the protective film side of the polarizing plate according to one aspect of the present invention is held by a holding device. Next, a step of adjusting the position of the polarizing plate with respect to the holding device by pressing at least a part of the outer peripheral surface of the polarizing plate opposite to the reference surface; and adjusting the position of the polarizing plate with respect to the holding device via an adhesive layer. Step of attaching the polarizing plate to the liquid crystal cell.

In the aforementioned manufacturing method, a liquid crystal panel is manufactured using a polarizing plate according to an aspect of the present invention. In the polarizing plate, although the polarizer protective layer for protecting the polarizer layer is one layer, the bending resistance of the laminated body including the protective film is 7.6 mN or more or 7.64 mN or more. Therefore, when adjusting the position of the polarizing plate with respect to the holding device, The reference plane is also pressed against the polarizing plate, and the deformation of the polarizing plate can also be suppressed, and the polarizing plate cannot be easily dropped from the holding device. Therefore, even if the polarizer protective layer that protects the polarizer layer is one layer, it is possible to suppress a decrease in manufacturing efficiency of the liquid crystal panel.

In one embodiment, the method may further include a step of removing the protective film from the polarizing plate attached to the liquid crystal cell.

In this case, it is possible to manufacture a liquid crystal panel with a reduction in the manufacturing efficiency and a reduction in the number of polarizer protective layers.

According to the present invention, it is possible to provide a polarizing plate and a method for manufacturing a liquid crystal panel that can suppress a decrease in the manufacturing efficiency of a liquid crystal panel even if the polarizer protective layer that protects the polarizer layer is one layer.

10‧‧‧ polarizing plate

10A, 10B‧‧‧polarizing plate (laminated body)

11‧‧‧Polarizer layer

12‧‧‧ polarizer protective layer

13‧‧‧ polarizing plate body

14‧‧‧ protective film

15‧‧‧ Adhesive layer

16‧‧‧ release film

20‧‧‧ LCD panel

21‧‧‧LCD unit

21a‧‧‧ surface

21b‧‧‧Back

30‧‧‧ Attraction disk (holding device)

40‧‧‧ Alignment Rod

40a‧‧‧Inner surface (reference surface)

50‧‧‧ base plate

51‧‧‧SUS board

52‧‧‧ glass plate

53‧‧‧block

54‧‧‧ rubber band

P‧‧‧Polarizer

Pa‧‧‧ side

FIG. 1 is a perspective view of a polarizing plate according to an embodiment.

FIG. 2 (a) is a perspective view of an embodiment of a liquid crystal panel manufactured using the polarizing plate shown in FIG. 1. FIG. Fig. 2 (b) is a side view of the liquid crystal panel shown in Fig. 2 (a).

Fig. 3 (a) is a side view of a state where the polarizing plate is held by a suction disk (holding device). Fig. 3 (b) is a plan view of a state where the polarizing plate is held by the suction disk (holding device).

Fig. 4 is a view showing a state after peeling the release film from the state shown in Fig. 3 (a).

FIG. 5 is a diagram for explaining a step (position adjustment step) of adjusting a position of a polarizing plate with respect to a holding device in a method of manufacturing a liquid crystal panel.

FIG. 6 is a diagram for explaining a step of bonding a polarizing plate to a liquid crystal cell in a method of manufacturing a liquid crystal panel.

FIG. 7 is a diagram for explaining an experimental experimental model of the state of the polarizing plate when the alignment rod is pressed against the polarizing plate in the position adjustment step. To confirm

FIG. 8 is a diagram showing an image at the time of a collision in a collision experiment using a polarizing plate of a comparative example.

FIG. 9 is a diagram showing an image at the time of impact in the impact experiment using the polarizing plate of the example.

Embodiments of the present invention will be described below with reference to the drawings. The same symbols are assigned to the same elements. Duplicate descriptions are omitted. The dimensional ratios of the drawings are not necessarily consistent with those of the explainers. In the description, the terms showing directions such as "up" and "down" are terms used for easy explanation according to the states shown in the drawings.

FIG. 1 is a perspective view of a polarizing plate according to an embodiment. The polarizing plate 10 shown in FIG. 1 is a polarizing plate for manufacturing a liquid crystal panel. The shape of the polarizing plate 10 viewed from the thickness direction of the polarizing plate 10 (the shape when viewed from above) is rectangular as shown in FIG. 1. The length of the short side of the rectangle is, for example, 50 mm to 80 mm, and the length of the long side is, for example, 90 mm to 135 mm. Specifically, one example of the polarizing plate 10 is a polarizing plate having a long side length of 113.15 mm and a short side of 64.80 mm, and another example of the polarizing plate 10 is a long side length of 128.26 mm and a short side length of 73.54 mm polarizer. The shape of the polarizing plate 10 when viewed from above is not limited to a rectangle, and may be, for example, a square. The shape of the polarizing plate 10 when viewed from above, What is necessary is just a shape corresponding to the shape of the liquid crystal panel 20 to which the polarizing plate 10 is applied. Generally, if the shape of the liquid crystal panel 20 is rectangular, the shape of the polarizing plate 10 is also rectangular, and if the shape of the liquid crystal panel 20 is square, the shape of the polarizing plate 10 is also square. In the following description, the shape of the polarizing plate 10 in a plan view is rectangular unless otherwise specified.

The polarizing plate 10 is a laminated polarizing plate, which includes a polarizing plate body 13 and a polarizing plate protective layer 12 laminated on a polarizing plate layer 11; a protective film 14 provided on the polarizing plate protective layer 12 for protection The polarizing plate body 13; the adhesive layer 15 is laminated on the polarizer layer 11 in contact with the polarizer layer 11; and a release film 16 is attached to the adhesive layer 15.

The polarizer layer 11 is a layer that selectively passes light (p-polarized light or s-polarized light) in the direction of the polarization axis of the polarizer layer 11 among the light incident on the polarizer layer 11. The material of the polarizer layer 11 is, for example, polyvinyl alcohol (PVA). The thickness of the polarizer layer 11 is, for example, 7 μm to 30 μm.

The polarizer protective layer 12 is a layer bonded to the polarizer layer 11 to protect the polarizer layer 11. The material of the polarizer protective layer 12 is, for example, triacetyl cellulose (TAC). The thickness of the polarizer protective layer 12 is, for example, 20 μm to 50 μm. The polarizer protective layer 12 is substantially transparent to the light incident on the polarizer layer 11.

The protective film 14 is a film provided on the surface of the polarizer protective layer 12 opposite to the polarizer layer 11 to prevent the polarizer body 13 from being injured. The protective film 14 is also a film for adjusting bending resistance to give the polarizing plate 10 a certain bending resistance. Since the protective film 14 is used In order to prevent the polarizing plate body 13 from being injured, there is a need for strength. Therefore, when the protective film 14 is laminated on the polarizer protective layer 12, the bending resistance can be adjusted. The protective film 14 is releasably bonded to the polarizer protective layer 12. The material of the protective film 14 includes, for example, polyethylene terephthalate (PET) and polypropylene (PP). The thickness of the protective film 14 is, for example, 30 μm to 90 μm. The preferred thickness of the protective film 14 is 45 μm to 80 μm.

The adhesive layer 15 is provided on the surface of the polarizer layer 11 opposite to the polarizer protective layer 12. The adhesive layer 15 is used to adhere a polarizing plate body 13 composed of a polarizer layer 11 and a polarizer protective layer 12 to a liquid crystal cell. The material of the adhesive layer 15 is, for example, an acrylic acid-based adhesive, and the thickness of the adhesive layer 15 is, for example, 5 μm to 30 μm.

The peeling film 16 is a film for preventing the polarizing plate 10 from being attached to other members or foreign matter from being attached to the adhesive layer 15 through the adhesive layer 15 until the polarizing plate 10 is attached to the liquid crystal cell. Since the release film 16 is used to prevent sticking and prevent foreign matter from being attached, the release film 16 cannot be required to have strength. Therefore, even if the release film 16 is bonded to the adhesive layer 15, the influence of the bending resistance is extremely small. The material of the release film 16 is, for example, PET and polyethylene, and the thickness of the release film 16 is, for example, 20 μm to 40 μm.

For convenience of explanation, the structure of the release film 16 is removed from the structure of the polarizing plate 10 shown in FIG. 1, that is, a protective film 14 is provided on one surface of the polarizing plate body 13, and the other surface (and The laminated body provided with the adhesive layer 15 on the opposite side of the protective film 14 is also referred to as a polarizing plate 10A. In addition, those who remove the protective film 14 from the polarizing plate 10A are also referred to as polarizers. Light plate 10B.

The bending resistance of the polarizing plate 10A belonging to the laminated body from which the release film 16 is removed from the polarizing plate 10 is 7.6 mN (776 mgf) or more and 7.64 mN (780 mgf) or more. The bending resistance of the polarizing plate 10A is 12.0 mN (1225 mgf) or less, and preferably 11.77 mN (1200 mgf) or less. In one embodiment, the bending resistance of the polarizing plate body 13 is 4.0 mN (408 mgf) or less or 3.92 mN (400 mgf) or less. Generally, the bending resistance of the polarizing plate body 13 is 2.9 mN or more or 2.94 mN or more.

The bending resistance exemplified above is a value measured by using a digital bending resistance / stiffness tester 4171E (Thwing-Albert Instrument Co.) as a bending resistance measuring device, and a Gurley formula is used as a measurement method.

Specifically, the above-mentioned exemplified bending resistance is the bending resistance measured in the following manner using the above-mentioned measuring machine. First, a sample to be measured is set on a measuring machine, and the reference position in the measuring machine is measured in the left-right direction, and the average value is set to the bending resistance of one measurement. This measurement of bending resistance was repeated 5 times, and the average value of 5 times was used as the bending resistance of one sample.

The polarizing plate 10 is produced in the following manner, for example. First, on one surface of the polarizer layer 11, a polarizer body 13 with a polarizer protective layer 12 formed is manufactured. Thereafter, a protective film 14 is bonded to the polarizer protective layer 12, and a surface of the polarizer layer 11 opposite to the polarizer protective layer 12 is bonded to a release film 16 to which an adhesive layer 15 is attached to obtain a polarizing plate 10.

Polarizer layer 11 and polarizer protective layer constituting polarizer 10 The material and thickness of 12 and protective film 14 and other parameters that affect the bending resistance are based on the fact that the polarizing plate 10 has both the properties of a polarizing plate, and the polarizing plate 10A has a bending resistance of 7.6 mN or more Way to choose. In one embodiment, the bending resistance of the polarizing plate 10 can be adjusted mainly by the thickness of the protective film 14. By setting the thickness of the protective film 14 to 30 μm to 90 μm in the above range, the bending resistance of the polarizing plate 10A is easy. The property is set to 7.6 mN or more or 7.64 mN or more.

Fig. 2 is a diagram for explaining the structure of an embodiment of a liquid crystal panel manufactured using the polarizing plate 10 shown in Fig. 1. Fig. 2 (a) is a diagram of a liquid crystal panel manufactured using the polarizing plate shown in Fig. 1. A perspective view of one embodiment of a liquid crystal panel. FIG. 2 (b) is a side view of the liquid crystal panel shown in FIG. 2 (a).

The liquid crystal panel 20 is formed by bonding a polarizing plate body 13 on an upper surface (a first main surface) 21 a and a back surface (a second main surface opposite to the first main surface) 21 b of the liquid crystal cell 21 via an adhesive layer 15.

The liquid crystal cell 21 may be one used in a known liquid crystal panel 20. For example, the liquid crystal cell 21 may be a glass substrate provided with a transparent electrode, an alignment film, a liquid crystal, an alignment film, a transparent electrode, a color filter, and a glass substrate.

The pair of polarizing plate bodies 13 included in the liquid crystal panel 20 are arranged for the liquid crystal cell 21 such that the polarization axes of the two polarizing plate bodies 13 are orthogonal to each other. In other words, the direction of the polarization axis of the polarizer layer 11 of the polarizer body 13 disposed on the back surface 21b is orthogonal to the direction of the polarization axis of the polarizer layer 11 of the polarizer body 13 disposed on the surface 21a.

Next, an example of a manufacturing method of the liquid crystal panel 20 using the polarizing plate 10 will be described.

When the liquid crystal panel 20 is manufactured using the polarizing plate 10, as shown in FIGS. 3 (a) and 3 (b), the polarizing plate 10 is held by a suction plate (holding device) 30 from the protective film 14 side. The suction disk 30 may be a vacuum suction disk using a vacuum, for example. An example of a material of the surface of the suction plate 30 that is in contact with the polarizing plate 10 is stainless steel (SUS). The drawing shows the suction disk 30 schematically. As shown in FIG. 3 (b), when viewed from the suction plate 30 side, the suction plate 30 holds the polarizing plate 10 so that two orthogonal sides of the polarizing plate 10 protrude from the suction plate 30 to the outside.

In this manner, the peeling film 16 is peeled from the polarizing plate 10 while the polarizing plate 10 is held by the suction disk 30. As a result, as shown in FIG. 4, the polarizing plate 10A is held on the suction plate 30.

Next, as shown in FIG. 5, the position of the polarizing plate 10A is adjusted with respect to the suction plate 30 (position adjustment step). In this position adjustment step, an alignment bar 40 having an L-shape in plan view is used. Specifically, the inner surface 40 a of the alignment bar 40 is pressed against the side surface (part of the outer peripheral surface) of the polarizing plate 10A protruding from the suction plate 30, and the polarizing plate 10A is aligned with respect to the suction plate 30. The thickness of the alignment rod 40 (the length in the thickness direction of the polarizing plate 10A) is generally the same as or greater than the thickness of the polarizing plate 10A. Thereby, the side surfaces (side surfaces of the long side and the short side) of the polarizing plate 10A protruding from the suction plate 30 can be pressed evenly. In the alignment bar 40, the length in the thickness direction of the polarizing plate 10A is, for example, 5 mm to 8 mm.

At this time, the static electricity on the side surface of the protective film 14 of the polarizing plate 10A The smaller the coefficient of friction, the smoother the polarizing plate 10A moves when pushed by the alignment bar 40, and the easier the position adjustment. The static friction coefficient is 0.24 or less, and may be 0.22 or less. In addition, when the static friction coefficient is less than 0.10, the polarizing plate 10A will move more than necessary when it is pushed by the alignment bar 40. Therefore, if the position adjustment is to be performed with good accuracy, it is usually 0.10 or more and 0.15 or more. It can also be 0.20 or more. For the measurement of the static friction coefficient, for example, a portable friction meter (produced by New East Science Co., Ltd.) can be used.

The inner surface 40a of the alignment rod 40, that is, the surface facing the polarizing plate 10A is a flat surface, and the inner surface 40a of the alignment rod 40 is a reference plane for alignment. Of the inner surface 40a, a region facing the side surface of the polarizing plate 10A may be a flat surface. When adjusting the position of the polarizing plate 10A with respect to the suction plate 30, the polarizing plate 10 can be aligned with the inner surface (reference surface) 40a, for example, the polarizing plate 10A can be pressed into the suction plate 30 side. For example, when the polarizing plate 10A protrudes from the suction plate 30 by about 8 mm in the longitudinal direction, the polarizing plate 10A can be pressed into the polarization plate 10A so as to protrude by about 3 to 4 mm.

Thereafter, as shown in FIG. 6, the polarizing plate 10A is bonded to the liquid crystal cell 21 (bonding step). When the polarizing plate 10A is bonded to the liquid crystal cell 21, the suction plate 30 is moved, and the polarizing plate 10A is arranged on a bonding region in the liquid crystal cell 21. After that, the suction plate 30 is tilted about 10 degrees with respect to the liquid crystal cell 21, and the polarizing plate 10A is bonded to the liquid crystal cell 21 from one side to the other side in the length direction of the polarizing plate 10A. After the polarizing plate 10A is attached to the liquid crystal cell 21, the suction plate is released. 30 for holding the polarizing plate 10A.

The polarizing plate 10A is bonded to the other surface of the liquid crystal cell 21 in the same manner as when the polarizing plate 10A is bonded to one surface (for example, the surface 21 a) of the liquid crystal cell 21.

After the polarizing plates 10A are bonded to both sides of the liquid crystal cell 21 in the manner described above, the protective film 14 is peeled from each polarizing plate 10A (protective film removing step). Thereby, the liquid crystal panel 20 in which the polarizing plates 10B are bonded to both surfaces of the liquid crystal cell 21 can be obtained.

In the polarizing plate 10 shown in FIG. 1, there is only one polarizer protective layer 12 for protecting the polarizer layer 11. In addition, in the liquid crystal panel 20 as a product, in particular, in the liquid crystal panel 20 that has been incorporated in a liquid crystal television, the protective film 14 has been removed. Therefore, the liquid crystal panel 20 is thinner than the polarizer protective layer 12 provided on both sides of the polarizer layer 11, that is, thinner than when the two polarizer protective layers 12 are provided on the polarizer layer 11. Therefore, the configuration of the polarizing plate 10 shown in FIG. 1 contributes to the reduction in thickness of the liquid crystal panel 20.

In this way, by providing only one polarizer protective layer 12 for protecting the polarizer layer 11, in order to reduce the thickness of the liquid crystal panel 20, for example, the configuration of the polarizing plate 10 shown in FIG. 1 may be considered. The structure in which the protective film 14 is not provided, that is, the liquid crystal panel is manufactured using substantially only the polarizing plate body 13.

However, when a liquid crystal panel is to be manufactured using the polarizing plate body 13 itself without the protective film 14, the bending resistance is small (for example, 3.92 mN or less). Therefore, the polarizing plate body 13 is When the position of the polarizer 10 is adjusted, the polarizing plate 10B may fall from the suction plate 30 due to the pressing of the alignment rod 40.

In this regard, in the polarizing plate 10 shown in FIG. 1, since the protective film 14 is provided for the polarizing plate body 13, even if the polarizing plate protective layer 12 included in the polarizing plate body 13 is one layer, the polarizing plate 10A It can also ensure bending resistance of 7.6mN or more or 7.64mN or more. As a result, when the position of the polarizing plate 10A is adjusted with respect to the attraction plate 30 (position adjustment step), even if the alignment bar 40 is pressed against the polarizing plate 10A, the polarizing plate 10A is not easily deformed by being pressed by the alignment bar 40 (for example bending). Therefore, the falling of the polarizing plate 10A from the attraction plate 30 due to the deformation of the polarizing plate 10A can be suppressed. Therefore, if the liquid crystal panel 20 is manufactured using the polarizing plate 10, the manufacturing efficiency of the liquid crystal panel 20 is not easily reduced. After the polarizing plate 10A is attached to the liquid crystal panel 20, the protective film 14 is peeled off. As described above, the constitution of the polarizing plate 10 contributes to the reduction in thickness of the liquid crystal panel 20. Furthermore, since the protective film 14 is provided so that the protective film 14 is in contact with the suction disk 30, the polarizer protective layer 12 is not damaged when the liquid crystal panel 20 is manufactured.

When the bending resistance of the polarizing plate body 13 is 4.0 mN or less or 3.92 mN or less, the polarizing plate body 13 itself is easily deformed (for example, bent). Therefore, it is effective to have a configuration in which the polarizing plate 10 including the protective film 14 and the bending resistance of the polarizing plate 10A is 7.6 mN or more or 7.64 mN or more.

In a form where the thickness of the protective film 14 that can be peeled from the polarizing plate body 13 is 30 μm to 90 μm, the polarizing plate 10A is easily provided with bending resistance of 7.6 mN or more or 7.64 mN or more, and peeling operation of the protective film 14 is easy. It is easy to impart 7.6mN to the polarizing plate 10A. The thickness of the protective film 14 is preferably 45 μm to 80 μm from the viewpoints of bending resistance of 7.64 mN or more and ease of peeling of the protective film 14.

The experimental results on the polarizing plate will be described below. The polarizing plates of Examples and Comparative Examples used in the experiments are as follows. Hereinafter, for convenience of explanation, the polarizing plates of Examples and Comparative Examples are referred to as polarizing plates P1 and P2.

A polarizing plate 10 having the structure shown in FIG. 1 was prepared as the polarizing plate P1 of the example. That is, a polarizer body 13 in which a polarizer protective layer 12 is laminated on a polarizer layer 11, a protective film 14 is provided on the polarizer protective layer 12, and an adhesive layer is provided on the polarizer layer 11. The polarizing plate 10 of 15 and the release film 16 serves as the polarizing plate P1. The material of the polarizer layer 11 is PVA, and its thickness is 28 μm. The material of the polarizer protective layer 12 is TAC, and its thickness is 40 μm. The material of the protective film 14 is PET, and its thickness is 50 μm. The material of the adhesive layer 15 is an acrylic adhesive, and its thickness is 25 μm. The material of the release film 16 is PET, which has a thickness of 38 μm and is easily bent to such an extent that the shape cannot be maintained alone.

The polarizing plate P2 of the comparative example has the same layer structure as the polarizing plate 10 of the example. In the comparative example, PET was used as the material of the protective film, and its thickness was set to 38 μm. That is, the polarizing plate P2 of the comparative example is a surface except for the thickness of the protective film and the surface on the opposite side (the protective film side surface of the polarizing plate P2) from the polarizer protective layer side of the protective film when the polarizing plate P2 is formed Except for the difference in state (static friction coefficient), it has the same configuration as the polarizing plate P1 of the example.

(1) Measurement of bending resistance

The bending resistance of the polarizing plates P1 and P2 of the examples and comparative examples was measured. The measurement was performed using the method described above, that is, a digital bending resistance / stiffness tester 4171E (Thwing-Albert Instrument Co.) was used as the bending resistance measuring device, and the measurement was performed according to a Gurley-type measurement method. Hereinafter, an object to be measured is referred to as a sample, and a measurement method is specifically described. In the measurement, a sample obtained by cutting a sample into a rectangular-shaped rectangular plate of 88.9 mm × 25.4 mm (3.5 inches × 1 inch) was used.

[Method for measuring bending resistance by a measuring machine (4171E)]

(a) Horizontal alignment of the measuring machine

(b) Set the sample information and measurement method of the corresponding sample to the measuring device (4171E).

(b-1) In order to set the length of the sample piece of the measuring machine, set the "Length" memory value of the measuring machine to "3.5". In addition to the "3.5" mentioned above, the options for "Length" also include "1", "1.5", "2.5", and "4.5". The unit of each memorized value is inch.

(b-2) To set the width of the measurement sample, set the "Width" memory value of the measuring device to "1". In addition to the "1", the "Width" memorized options include "5" and "2". The unit of each memorized value is inch.

(b-3) To set the mounting position of the hammer, set the "WEIGHT POSITION" memory value of the measuring machine to "1". The "WEIGHT POSITION" memorized options include "2" and "4" in addition to the "1" mentioned above. The unit of each memorized value is inch.

(b-4) In order to set the used hammer to the measuring device, set the "WEIGHT gm˙" memory value of the measuring device to "25". In addition to the "25", the "WEIGHT gm˙" memorized options include "5", "50", and "200".

(c) Fix one corner of the sample piece to the clamp of the measuring machine. At this time, the corner fixed to the clamp was tightly attached to the upper section of the clamp, and 6.35 mm (0.25 inch) was inserted into the clamp. The angle opposite to the corner of the sample piece embedded in the clamp is fixed to a triangular-shaped aid. At this time, the length of the repeating area with the aid is also set to 6.35 mm (0.25 inches).

(d) Next, the aid is brought into close contact with the sample piece (positioned to a measurement value reference of 0.1 or less).

(e) Stop the vibrator hammer on which the hammer is installed (positioned at 0 point).

(f) The "MOTOR DIRECTION" in the measuring machine was operated, and the bending resistance of the sample piece was measured for the left and right sides, respectively. After the left and right measurements are completed, the left and right averages are used as the bending resistance for one measurement.

(g) Repeat the measurement steps shown in (a) to (f) 5 times, and use the average value as the bending resistance of the sample.

Using the polarizing plates P1 and P2 as the above samples, the bending resistance was measured according to the above procedures. Among the polarizing plates P1, the bending resistance of the polarizing plate body 13 composed of the polarizing plate layer 11 and the polarizing plate protective layer 12 was also measured. Furthermore, the polarizing plate body 13 in the comparative example was also measured for bending resistance.

The measurement results of the bending resistance are shown in Table 1. The unit of bending resistance output from the measuring device is mgf. Therefore, in Table 1, the number is indicated together with the value indicated by "mgf". Values are converted to SI units. Numerical values converted to SI units are shown in parentheses in Table 1.

(2) Measurement of static friction coefficient of polarizing plate

The static friction coefficients were measured for the polarizing plates P1 and P2. The portable friction meter (model: 94i-II New East Science Co., Ltd.) was used to measure the static friction coefficient of the side surface of the protective film. The slider of the portable friction meter was coated with hard chromium ( hard chrome). As a result of measurement, the static friction coefficient of the side surface of the protective film of the polarizing plate P1 is 0.22, and the static friction coefficient of the side surface of the protective film of the polarizing plate P2 is 0.25.

(3) Impact simulation experiment of polarizing plate and alignment rod

An experiment was performed to confirm the state of the polarizing plate when the alignment bar 40 was pressed against the polarizing plate in the position adjustment step. The impact simulation experiment performed the following experiments on the polarizing plates P1 and P2. In the following description, the polarizing plates P1 and P2 are referred to as a polarizing plate P.

In this experiment, as shown in FIG. 7, the SUS plate (stainless steel plate) 51 is arranged on the base plate 50 as a model of the suction plate 30, and the side Pa of the polarizing plate P protrudes from the SUS plate 51. Way The polarizing plate P is disposed on the SUS plate 51. Ten glass plates (100 mm × 100 mm in size) are set on the polarizing plate P, and a certain load is applied to the polarizing plate P toward the SUS plate 51 side, instead of the adsorption force of the polarizing plate P by the suction disk 30. Further, toward the side Pa of the polarizing plate P protruding from the SUS plate 51, from a position separated from the SUS plate 51 by a certain distance (the position shown by the dotted line in FIG. 7), a rectangular parallelepiped block 53 hits the polarizing plate P To replace the alignment bar 40. In the experiment, the state of the polarizing plate P at the time of the impact was photographed from the side with an ultra-high-speed camera (not shown).

The impact of the block 53 on the polarizing plate P is performed in the following manner. As shown in FIG. 7, with the rubber band 54 placed between the lower surface of the base plate 50 and the side surface of the block 53 opposite to the SUS plate 51, the block 53 is separated from the SUS plate 51 to the block. The distance between 53 and the facing surface of the SUS plate 51 and the side surface Pa of the polarizing plate P becomes a certain distance, and the block 53 strikes the polarizing plate P by the restoring force of the rubber ring 54.

The conditions of the ultra-high-speed camera used in the experiment are as follows.

˙Super-speed camera: i-SPEED 3 (produced by Olympus)

˙Lens: 24-70mm F2.8 EX DG MACRO F / SIGMA

˙Frame rate (FPS): 2000fps

In the case where the polarizing plate P1 and the polarizing plate P2 were used as the polarizing plate P, the experiments described with respect to the polarizing plate P were respectively performed. In the experiment using the polarizing plate P2 of the comparative example having a bending resistance of 7.26 mN, as shown in FIG. 8, the polarizing plate P2 exhibited a large curvature. When the polarizing plate P2 is bent to the extent shown in FIG. 8, it is presumed that the polarizing plate P2 will fall off the suction plate 30 due to the bending. In contrast, bending resistance is used In the experiment of the polarizing plate P1 of the example of 7.75 mN, as shown in FIG. 9, it can be seen that the bending of the polarizing plate P1 is reduced and there is almost no bending. The release film 16 to be used is such a degree that it is easily bent and cannot maintain its shape alone, and does not affect the bending resistance of the polarizing plate P1.

Therefore, if the polarizing plate 10A aligned by the alignment bar 40 is held at the attraction plate 30 and the bending resistance is 7.6 mN or more or 7.64 mN or more, even the polarizer protective layer of the polarizing plate body 13 The number of 12 is one layer, and the polarizing plate 10A does not fall off the suction plate 30 and the polarizing plate 10A can be aligned with respect to the suction plate 30.

Although various embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and experimental examples, and various changes can be made without departing from the scope of the invention.

For example, the alignment rod 40 is not limited to an L-shaped one, and may be a straight one as long as it has a reference surface capable of adjusting the position of the polarizing plate 10A. In the position adjustment step, although the two sides of the polarizing plate have been exemplified to be pressed against the reference surface, the position adjustment can be performed by pressing a part of the outer periphery of the polarizing plate against the reference surface. . The liquid crystal panel 20 has been described in a form in which the polarizing plate body 13 is bonded via the adhesive layer 15, that is, the polarizing plate 10B is bonded to the liquid crystal cell 21. However, in the manufacturing stage, the liquid crystal panel 20 may be a polarizing plate 10A formed by providing a protective film 14 on the polarizing plate body 13 and bonded to both sides of the liquid crystal cell 21, that is, as described in the above embodiment. The previous step of the fitting step. At this time, when the liquid crystal display device is manufactured using the liquid crystal panel 20, the protective film 14 may be peeled off.

Claims (9)

A polarizer includes a polarizer layer for selectively passing light polarized in a predetermined direction. The polarizer includes a polarizer body, and a polarizer layer is laminated on the polarizer layer to protect the polarizer layer. A protective film; a protective film laminated on the polarizer protective layer; and an adhesive layer on the opposite side of the polarizer layer opposite to the polarizer protective layer and laminated with the polarizer layer; The laminated body composed of the adhesive layer, the polarizing plate body, and the protective film has a bending resistance of 7.6 mN or more, and the bending resistance of the polarizing plate body is 4.0 mN or less. The polarizing plate according to item 1 of the scope of patent application, wherein the bending resistance of the laminated body is 7.64 mN or more. The polarizing plate according to item 1 of the scope of patent application, wherein the bending resistance of the polarizing plate body is 3.92 mN or less. The polarizing plate according to item 1 of the scope of patent application, wherein the shape viewed from the thickness direction of the polarizing plate is a rectangle; the long side of the rectangle is 90 mm to 135 mm; and the short side of the rectangle is 50 mm to 80 mm. The polarizing plate according to item 1 of the scope of patent application, wherein the material of the protective film is polyethylene terephthalate or polypropylene. The polarizing plate according to item 1 of the scope of patent application, wherein the thickness of the protective film is 30 μm to 90 μm. The polarizing plate according to any one of claims 1 to 6, wherein the protective film is provided on the polarizer protective layer in a peelable manner. A method for manufacturing a liquid crystal panel. The liquid crystal panel is formed by attaching a polarizing plate body to a liquid crystal cell, and the polarizing plate body is useful for laminating a polarizer layer that selectively passes light polarized in a predetermined direction. Formed by protecting the polarizer protective layer of the aforementioned polarizer layer, the manufacturing method of the liquid crystal panel includes: maintaining a polarizing plate described in any one of the first to seventh patent application scopes by a holding device; A step of adjusting the position of the polarizing plate with respect to the holding device by pressing at least a part of the outer peripheral surface of the polarizing plate to a reference surface in a state of the protective film side; and through the bonding And a step of bonding the polarizing plate adjusted to the holding device to the liquid crystal cell. The method for manufacturing a liquid crystal panel according to item 8 of the scope of patent application, further comprising the step of removing the protective film from the polarizing plate attached to the liquid crystal cell.