JP2021103287A - Manufacturing method of laminate and bonding device - Google Patents

Abstract

To provide a manufacturing method of a laminate and a bonding device which can easily control the quantity and a direction of warpage of a laminate having an optical display panel and an optical film after bonding.SOLUTION: A manufacturing method of a laminate 300 having an optical display panel 100 and an optical film 200 includes a pressing process of pressing the laminate 300 formed by the optical display panel 100 and the optical film 200 between a pair of rolling nip rolls 21, 22. In the pressing process, warpage is applied to the laminate 300 along a surface of the nip roll 21.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for manufacturing a laminate and a laminating device used for an optical display device such as a liquid crystal display.

Conventionally, an optical film such as a polarizing plate has been bonded to an optical display panel such as a liquid crystal panel to obtain a laminated body.

Japanese Unexamined Patent Publication No. 2013-137538

However, in an optical display panel such as a liquid crystal panel, warpage occurs after bonding due to residual stress of the optical display panel and the optical film at the time of bonding, shrinkage / expansion of the optical film over time, and the like. I had something to do. This tendency becomes even more pronounced as the optical display panel becomes larger. As one method for solving the problem of warpage, there is a method in which the optical display panel is given a slight warp in advance in the direction opposite to the warp direction.

An object of the present invention is to provide a method for manufacturing a laminated body and a bonding device capable of easily controlling the amount and direction of warpage of a laminated body having an optical display panel and an optical film after bonding. To do.

The method according to the present invention is a method for manufacturing a laminate having an optical display panel and an optical film.
A pressing step of pressing the laminate of the optical display panel and the optical film between a pair of rotating nip rolls is provided.
In the pressing step, the laminated body is warped along the surface of one of the nip rolls.

Here, the above method is a step of transporting the optical display panel toward the pair of nip rolls by the upstream horizontal transport means, and
Further provided with a step of transporting the laminated body discharged from the pair of nip rolls by the downstream horizontal transport means.
The rotation axes of the pair of nip rolls are arranged vertically apart from each other.
In the pressing step, the height of the portion of the laminated body sandwiched between the pair of nip rolls is lower or higher than the height of the upper surface of the upstream horizontal transport means and the height of the upper surface of the downstream horizontal transport means. Therefore, the laminated body can be warped.

Further, in the above method, the laminated body is not warped until the leading end portion in the flow direction of the laminated body reaches the top of the downstream horizontal transport means.
After the leading end portion of the laminated body in the flow direction reaches the top of the downstream horizontal transport means, the laminated body is given the warp.
The warp can be eliminated while the rear end of the optical display panel in the flow direction is supported by the upper surface of the upstream horizontal transport means.

Further, in the above method, the upstream horizontal transport means and the downstream horizontal transport means can be roller conveyors, respectively.

Further, the diameter of the one nip roll may be larger than the diameter of the other nip roll.

Further, the optical film is a polarizing plate, and in a laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate and the rotation axes of the pair of nip rolls can be arranged in parallel. ..

Further, the surface of the optical display panel has a rectangular shape, and in the laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate is parallel to the lateral direction of the surface of the optical display panel. Can be placed.

Further, the optical display panel is a liquid crystal panel, and can be attached so that the transmission axes of the polarizing plates are substantially parallel to the short side of the liquid crystal panel. Further, a polarizing plate can be attached to the TFT side of the liquid crystal panel.

The bonding device according to the present invention includes a pair of nip rolls that press a laminate of an optical display panel and an optical film, and a warp imparting mechanism that warps the laminate along the surface of one of the nip rolls. And.

Here, the rotation axes of the pair of nip rolls are arranged apart from each other in the vertical direction.
The warp imparting mechanism is an upstream horizontal transport means for transporting an optical display panel to the pair of nip rolls.
A downstream horizontal transport means for transporting a laminate of the optical display panel and the optical film discharged from the pair of nip rolls, and
The height of the portion of the laminated body sandwiched between the pair of nip rolls is larger than the height of the laminated body transported by the upstream horizontal transport means and the height of the laminated body transported by the downstream horizontal transport means. It can also have a positioning mechanism that defines the position of the pair of nip rolls so that it is also low or high.

Further, the apparatus sets the height of the portion of the laminated body sandwiched between the pair of nip rolls until the leading end portion in the flow direction of the laminated body reaches above the downstream horizontal transport means. Maintain the same height as the height of the upper surface of the upstream horizontal transport means and the height of the upper surface of the downstream horizontal transport means.
After the leading end of the laminated body in the flow direction reaches the top of the downstream horizontal transport means, the height of the portion of the laminated body sandwiched between the pair of nip rolls is set to the height of the upstream horizontal transport means. The positions of the pair of nip rolls are changed with respect to the upstream horizontal transport means and the downstream horizontal transport means so as to be lower or higher than the height of the upper surface and the height of the upper surface of the downstream horizontal transport means.
While the rear end of the optical display panel in the flow direction is supported by the upper surface of the upstream horizontal transport means, the height of the portion of the laminated body sandwiched between the pair of nip rolls is set to the upstream horizontal. A control unit that controls the positioning mechanism can be further provided so as to return to the same height as the height of the upper surface of the transport means and the height of the upper surface of the downstream horizontal transport means.

Further, the upstream horizontal transport means and the downstream horizontal transport means can be roller conveyors, respectively.

Further, the diameter of the one nip roll may be larger than the diameter of the other nip roll.

Further, the optical film is a polarizing plate, and in a laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate and the axes of the pair of nip rolls can be arranged in parallel.

Further, the surface of the optical display panel has a rectangular shape, and in the laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate is parallel to the lateral direction of the surface of the optical display panel. Can be placed.

Further, the optical display panel is a liquid crystal panel, and the polarizing plate can be attached to the TFT side of the liquid crystal panel.

According to the present invention, there is provided a method for manufacturing a laminated body and a bonding device capable of easily controlling the amount and direction of warpage of a laminated body having an optical display panel and an optical film after bonding.

FIG. 1 (a) is a schematic view showing a cross-sectional structure of a liquid crystal panel (optical display panel) according to an embodiment of the present invention, and FIG. 1 (b) is a polarized light according to an embodiment of the present invention. It is a schematic diagram which shows the cross-sectional structure of a plate (optical film). FIG. 2 is a schematic view of a bonding device according to an embodiment of the present invention. FIG. 3 is a schematic view of a bonding device according to an embodiment of the present invention, and is a diagram showing a state following FIG. FIG. 4 is a diagram showing the relationship between the length L of the liquid crystal panel in the transport direction and H1'. 5 (a) to 5 (c) are schematic end face views (horizontal direction is longitudinal direction) viewed from the lateral direction of the laminated bodies of various modes after pasting. 6A and 6B are schematic views showing an outline of the fixed warp amount in the examples, in which FIG. 6A shows the head fixed warp amount and FIG. 6B shows the rear fixed warp amount.

An embodiment of the present invention will be described with reference to the drawings. The dimensions of the drawings are arbitrary for the purpose of explaining the invention.

In the present embodiment, a method and an apparatus for bonding the liquid crystal panel and the polarizing plate will be described by taking a case where the optical display panel is a liquid crystal panel and the optical film is a polarizing plate as an example. First, the target liquid crystal panel 100 and the polarizing plate 200 will be described with reference to FIGS. 1 (a) and 1 (b).

As shown in FIG. 1A, the liquid crystal panel 100 can include a first transparent substrate 100A, a liquid crystal layer 100B, and a second transparent substrate 100C in this order. In the case of a liquid crystal panel, the material of the first and second transparent substrates can typically be glass.

In the present embodiment, the shape of the liquid crystal panel 100 is a rectangular shape.

The size of the rectangle of the liquid crystal panel 100 is not particularly limited, but the size of the long side can be 20 to 2600 mm. In particular, since the problem of warpage tends to occur more easily in the case of a large liquid crystal panel, it is preferable that the size of the long side is 1200 mm or more.

The thickness of the liquid crystal panel 100 is not particularly limited, but can be, for example, about 0.5 to 5 mm, preferably 1 to 5 mm.

As shown in FIG. 1B, the polarizing plate 200 is placed on a pair of protective films 200A and 200C, a polarizing element layer 200B arranged between the pair of protective films 200A and 200C, and one protective film 200C. It can have the provided pressure-sensitive adhesive / adhesive layer 200D.

Examples of the protective films 200A and 200C include general-purpose protective films in the technical field of polarizing plates such as triacetyl cellulose film (hereinafter, may be referred to as "TAC"), cycloolefin film, and acrylic film. In addition, in FIG. 1B, the cross-sectional structure of the polarizing plate in which the protective films 200A and 200B are provided on both sides of the polarizing element layer 200B is shown. A plate (single protective polarizing plate) can also be applied to the present invention. Although not shown, in the case of a single protective polarizing plate, the pressure-sensitive adhesive / adhesive layer 200D is usually provided directly on the surface of the polarizer layer 200B that does not have the protective film.

The polarizer forming the polarizer layer 200B can be a polyvinyl alcohol film dyed with a dichroic dye such as iodine, and can be produced by uniaxial stretching. Hereinafter, the polyvinyl alcohol film dyed with a dichroic dye such as iodine in this way may be referred to as "PVA".

The pressure-sensitive adhesive / adhesive layer 200D can be, for example, an acrylic resin layer.

The thickness of the polarizing plate 200 is not particularly limited, but can be, for example, 25 to 200 μm.

In the present embodiment, the polarizing plate 200 is attached to one surface of the liquid crystal panel 100 via the pressure-sensitive adhesive / adhesive layer 200D.

FIG. 2 is a schematic view of the bonding device 1 according to the first embodiment of the present invention. The bonding device 1 according to the present embodiment mainly includes an upstream roller conveyor 10, a pair of nip rolls 21 and 22, a downstream roller conveyor 40, a positioning mechanism 50 for adjusting the height of the pair of nip rolls 21 and 22, and a positioning mechanism. A control unit 60 for controlling 50 is provided, and a liquid crystal panel 100 and a polarizing plate 200 are bonded together to manufacture a laminated body 300. A pair of nip rolls 21 and 22, an upstream roller conveyor 10, a downstream roller conveyor 40, and a positioning mechanism 50 constitute a warp imparting mechanism 5.

The upstream roller conveyor (upstream horizontal transfer means) 10 includes a plurality of transfer rolls 10a, and the rotation axes of the transfer rolls are arranged in the horizontal direction and parallel to each other in the horizontal plane. The upstream roller conveyor 10 conveys the liquid crystal panel 100 supplied from a supply source (not shown) in the horizontal direction (from left to right in FIG. 1) on the upper surface of the upstream roller conveyor, and a pair of nip rolls 21 and 22. Supply in between.

In the present embodiment, the upstream roller conveyor 10 arranges the liquid crystal panel 100 so that both rectangular surfaces face in the vertical direction and the lateral direction of the rectangular surfaces is parallel to the axes of the nip rolls 21 and 22. Transport to.

The nip rolls 21 and 22 have rotating shafts 21a and 22a, respectively, the rotating shafts 21a and 22a are arranged apart from each other in the vertical direction, and the rotating shafts 21a and 22a are parallel to each other and the transport roll of the upstream roller conveyor 10. It is arranged parallel to the rotation axis of 10a. The material of the surface of the nip roll is not particularly limited, and rubber, metal, or the like can be applied, but rubber is preferable from the viewpoint of not significantly damaging the liquid crystal panel.

In this embodiment, the diameter of the upper nip roll 21 is made larger than the diameter of the lower nip roll 22. As a result, an appropriate warp can be given to the laminated body 300 along the upper nip roll 21 having a large diameter, while the lower nip roll 22 having a small diameter can sufficiently press the laminated body 300. Therefore, it is preferable.

The diameter of the upper nip roll 21 can be 30 to 300 mm. Further, the diameter of the lower nip roll 22 can be 10 to 100 mm.

Since the laminate 300 is transported from the upstream side (left side) to the downstream side (right side) of FIG. 1, the upper nip roll 21 can move counterclockwise in FIG. 1 and the lower nip roll 22 can move clockwise. .. The pair of nip rolls may be drive rolls or driven rolls, and it is preferable that at least one of them is a drive roll.

The polarizing plate 200 is supplied from the polarizing plate roll 30 to the lower nip roll 22. In the present embodiment, the direction of the transmission axis of the polarizing plate 200 is arranged parallel to the rotation axis of the nip rolls 21 and 22. That is, the direction of the absorption axis of the polarizing plate is parallel to the transport direction of the liquid crystal panel. A polarizing plate 200 is attached to the liquid crystal panel 100 between the nip roll 21 and the nip roll 22, and a laminate 300 containing these is obtained and discharged to the downstream side.

The polarizing plate 200 is supported on the separate film 210 to protect the adhesive / adhesive layer, and the lower nip roll is in a state where only the polarizing plate 200 is half-cut according to the size of the liquid crystal panel 100. The separate film 210 is conveyed via 22 and is collected by the reel 80 after the polarizing plate is attached. By using the separate film 210 in this way, it is possible to prevent foreign matter and the like from adhering to the pressure-sensitive adhesive / adhesive layer on the polarizing plate 200.

Although not shown, the pair of nip rolls 21 and 22 are provided with a pressure applying mechanism so that one nip roll is pressed against the other nip roll at a predetermined pressure. As a result, the laminated body 300 supplied between the pair of nip rolls 21 and 22 can be sandwiched from both sides in the thickness direction, and the liquid crystal panel 100 and the polarizing plate 200 can be pressed and brought into close contact with each other.

The pressing pressure can be appropriately set according to the amount of warpage required by the laminated body 300, the characteristics of the liquid crystal panel 100 and the polarizing plate 200, and the like, and can be, for example, 0.1 to 0.7 MPa.

The downstream roller conveyor (downstream horizontal transfer means) 40 includes a plurality of transfer rolls 40a, and the rotation axes of the transfer rolls 40a are arranged in the horizontal direction and parallel to each other in the horizontal plane. The downstream roller conveyor 40 conveys the laminated body 300 discharged from the pair of nip rolls 21 and 22 in the horizontal direction (direction from left to right in FIG. 1) on the upper surface. The obtained laminate 300 is used in the subsequent assembly step of the liquid crystal display.

The positioning mechanism 50 can move the positions of the pair of nip rolls 21 and 22 in the vertical direction. As shown in FIG. 2, the positioning mechanism 50 sets the height H1 of the portion P sandwiched between the pair of nip rolls 21 and 22 in the laminated body 300 to the height H2 of the upper surface of the upstream roller conveyor 10 and the downstream side. The height of the upper surface of the roller conveyor 40 can be the same as the height H3. Usually, the height H2 and the height H3 are the same. The positioning mechanism 50 may position one of the nip rolls 21 and 22 and slide on one of the nip rolls, but the positioning mechanism 50 controls the positioning of both nip rolls 21 and 22. You can also.

Further, as shown in FIG. 3, the positioning mechanism 50 sets the height H1 of the portion P sandwiched between the pair of nip rolls 21 and 22 in the laminated body 300 to the height H2 of the upper surface of the upstream roller conveyor 10 and the downstream side. The height of the upper surface of the roller conveyor 40 can be made lower than the height H3.

When the value of the height H1 when the height H1 becomes lower than the height H2 and the height H3 is H1min, H1min is preferably 1 mm or more lower than the height H2 and the height H3, and is preferably 2 mm or more lower. More preferably, it is more preferably 3 mm or more lower. There is no particular upper limit on the height difference, but it can be, for example, 10 mm or less.

Here, the height H2 of the upper surface of the upstream roller conveyor 10 can be rephrased as the height of the lower surface of the liquid crystal panel 100 horizontally conveyed by the upstream roller conveyor 10, and the height of the upper surface of the downstream roller conveyor 40. H3 can be rephrased as the height of the lower surface of the laminated body 300 that is horizontally conveyed by the downstream roller conveyor 40. Further, the height H1 of the portion P sandwiched between the pair of nip rolls 21 and 22 in the laminated body 300 is the lowest portion of the bottom surface of the portion P sandwiched between the pair of nip rolls 21 and 22 in the laminated body 300. The height.

The distance CV1 between the rotating shafts 21a and 22a of the pair of nip rolls 21 and 22 and the rotating shafts of the rolls 10a1 closest to the nip rolls 21 and 22 in the upstream roller conveyor 10 and the pair of nip rolls 21 and 22. The distance CV2 between the rotating shafts 21a and 22a and the rotating shaft of the roll 40a1 closest to the nip rolls 21 and 22 in the downstream roller conveyor 40 in the transport direction is also not particularly limited, but is included in the pair of nip rolls 21 and 22. It is preferable that the diameter of the roll on the large diameter side is about 2 to 5 times. Further, the length of the liquid crystal panel 100 in the transport direction (for example, the length of the long side) exceeds CV1 + CV2 and is usually twice or more.

The control unit 60 controls the positioning mechanism 50 to move the pair of nip rolls 21 and 22 up and down to change the height H1 of the portion P sandwiched between the pair of nip rolls 21 and 22 in the laminated body 300. Specifically, in the present embodiment, the control unit 60 fluctuates the height H1 of the portion P up and down when one liquid crystal panel 100 passes between the pair of nip rolls 21 and 22.

Specifically, the control unit 60 can change the height H1 as shown in FIG. The horizontal axis is the length of the liquid crystal panel 100 in the transport direction (for example, the longitudinal direction or the lateral direction of the rectangle), and the length L = 0 is the end of the bonding start side (lead side in the transport direction). The length Lmax is the end portion on the bonding end side (rear end side in the transport direction). The height H1 on the vertical axis is between the pair of nip rolls 21 and 22 in the laminated body 300 with reference to the height H2 on the upper surface of the upstream roller conveyor 10 and the height H3 on the upper surface of the downstream roller conveyor 40. It is the height H1 of the sandwiched portion P, and the minus sign means that it is lower than the heights H2 and H3.

The height H1 is maintained at 0 from the length 0 (bonding start position) to the length L1, decreases from the length L1 to the length L2, and the heights H2 and H3 from the length L2 to the length L3. The height is maintained at a lower H1 min, rises from the length L3 to the length L4, and is maintained at 0 from the length L4 to the length Lmax (bonding end position). In this embodiment, Lmax corresponds to the length of the long side of the liquid crystal panel.

L1 can be 10 to 500 mm, L2-L1 can be 100 to 2500 mm, Lmax-L4 can be 10 to 500 mm, and L4-L3 can be 10 to 500 mm.

The height H1min is preferably set to the above-mentioned value.

In other words, the control unit 60 is laminated until the leading end portion F of the laminated body 300 formed between the pair of nip rolls 21 and 22 comes into contact with the upper surface (which may be a part) of the downstream roller conveyor 40. The height H1 of the portion P sandwiched between the pair of nip rolls in the body 300 is maintained at the same height as the height H2 of the upper surface of the upstream roller conveyor 10 and the height H3 of the upper surface of the downstream roller conveyor 40. , Controls the positioning mechanism 50.

Further, in the control unit 60, after the front end F of the laminate 300 comes into contact with the upper surface (may be a part) of the downstream roller conveyor 40, the rear end R of the laminate 300 is the upstream roller conveyor. The height H1 of the portion P sandwiched between the pair of nip rolls in the laminated body 300 is set to the height H2 of the upper surface of the upstream roller conveyor 10 and the downstream roller conveyor in a state of being in contact with the upper surface (part may be a part) of the upstream roller conveyor 10. The positioning mechanism 50 is controlled so that the height of the upper surface of the 40 is lower than the height H3.

Further, the control unit 60 is in a state where the front end portion F of the laminated body 300 is in contact with the upper surface (may be a part) of the downstream roller conveyor 40, and the rear end portion of the laminated body 300 is in contact with the control unit 60. The height of the portion P sandwiched between the pair of nip rolls in the laminated body 300 is set to the height of the upper surface of the upstream roller conveyor 10 while R is in contact with the upper surface (which may be a part) of the upstream roller conveyor. The positioning mechanism 50 is controlled so as to return to the same height as the height H3 of the upper surface of the H2 and the downstream roller conveyor 40, and then the same height until the laminated body 300 is discharged from between the pair of nip rolls. To maintain.

The timing of the height fluctuation of the control unit 60 is such that the front end F and the rear end R of the liquid crystal panel 100 to be conveyed are detected by an appropriate sensor or the like, the speed of the transfer line is recognized, and the like. It can be realized by the method of.

Subsequently, a method of manufacturing the optical display device according to the embodiment of the present invention will be described.

First, as shown in FIG. 2, the liquid crystal panel 100 is supplied between the pair of nip rolls 21 and 22 by the upstream roller conveyor 10, and the polarizing plate 200 supplied from the polarizing plate roll 30 is supplied to the surface of the lower nip roll 22. It is supplied between the pair of nip rolls 21 and 22 along the line, and the laminated body 300 of the liquid crystal panel 100 and the polarizing plate 200 is pressed by the pair of nip rolls 21 and 22. As a result, the liquid crystal panel 100 and the pressure-sensitive adhesive / adhesive layer 200D of the polarizing plate 200 come into contact with each other, and the liquid crystal panel 100 is attached in order from the front end portion F to the rear end portion R.

Here, the control unit 60 is a portion P sandwiched between a pair of nip rolls 21 and 22 in the laminated body 300 until the leading end portion F in the flow direction of the laminated body 300 reaches the top of the downstream roller conveyor 40. The positioning mechanism 50 is controlled so that the height H1 of the above is the same as the height H2 of the upper surface of the upstream roller conveyor 10 and the height H3 of the upper surface of the downstream roller conveyor 40, and the laminated body 300 is warped. Absent. As a result, damage to the front end portion F of the laminated body 300 and the like is suppressed.

After that, the transport of the laminated body 300 proceeds, and after the leading end portion F of the laminated body 300 in the flow direction reaches the top of the downstream roller conveyor 40, the control unit 60 has the portion P of the laminated body 300 on the upstream side. The positioning mechanism 50 is controlled so as to be lower than the height H2 of the upper surface of the roller conveyor 10 and the height H3 of the upper surface of the downstream roller conveyor 40. As a result, the laminated body 300 is given a warp along the upper nip roll 21, and the liquid crystal panel 100 and the polarizing plate 200 are attached by the pair of nip rolls 21 and 22 in the state where the warp is given.

After that, as the transportation of the laminated body 300 further progresses, the control unit 60 in the laminated body 300 while the rear end portion R in the flow direction of the liquid crystal panel 100 is supported by the upper surface of the upstream roller conveyor 10. The positioning mechanism 50 is set so that the height of the portion P sandwiched between the pair of nip rolls 21 and 22 is returned to the same height as the height of the upper surface of the upstream roller conveyor 10 and the height of the upper surface of the downstream roller conveyor 40. Control and eliminate warpage. As a result, damage to the rear end portion R of the laminated body 300 and the like is suppressed.

In this way, the liquid crystal panel 100 and the polarizing plate 200 are bonded together in a warped state, and the formation of the laminated body 300 is completed.

Next, a liquid crystal display (optical display device) can be obtained by going through a step of combining the laminated body 300 with a backlight or the like, if necessary.

Subsequently, the operation of the present embodiment will be described.

In the manufacture of a liquid crystal display, polarizing plates are attached to both sides of a liquid crystal panel, and the transmission axes of the two polarizing plates are arranged perpendicular to each other (cross Nicol). Further, since the polarizer of the polarizing plate is usually manufactured through stretching, the polarizing plate tends to shrink in the direction orthogonal to the transmission axis, that is, in the direction parallel to the absorption axis.

In the present embodiment, the transmission axis of the polarizing plate 200 is parallel to the rotation axes 21a and 22a between the pair of nip rolls 21 and 22, that is, in the direction orthogonal to the transport direction of the laminated body 300. In the conventional method, in FIG. 2, the liquid crystal panel 100 and the polarizing plate 200 are attached under the condition that the state of no warp is maintained between the pair of nip rolls 21 and 22.

In particular, the liquid crystal panel 100 is arranged so that the lateral direction of the liquid crystal panel 100 is parallel to the transmission axis of the polarizing plate 200, in other words, the longitudinal direction of the liquid crystal panel 100 is parallel to the absorption axis of the polarizing plate 200. When the polarizing plate 200 is attached to the polarizing plate 200, the polarizing plate 200 contracts in the absorption axis direction after the attachment, and the laminated body 300 after the attachment is formed on the surface (lower surface) of the polarizing plate 200 as shown in FIG. ) Is a concave surface, and the surface of the liquid crystal panel 100 (the upper surface opposite to the surface to be bonded to the polarizing plate 200) is easily warped so as to be a convex surface. In FIGS. 5A to 5C, the horizontal direction is the longitudinal direction of the laminated body 300 and the liquid crystal panel 100. Such warpage leads to defects such as light leakage in the liquid crystal display after combination with the backlight, so it may be required to reduce the amount of warpage.

In particular, as shown in FIG. 5 (b), when a polarizing plate 200 having an absorption axis parallel to the longitudinal direction is attached to the TFT side surface 100 TFT of the liquid crystal panel 100, the liquid crystal panel is as shown in FIG. 5 (a). It is not preferable that the side surface 100CF of the color filter of 100 is a convex surface, and it is preferable that there is no warp as shown in FIG. 5 (b), but it is preferable that the side surface 100CF is warped in the opposite direction as shown in FIG. 5 (c). In some cases.

According to the present embodiment, when the laminated body 300 is pressed between the pair of nip rolls, the laminated body 300 is warped along the surface of one nip roll 21 as shown in FIG. That is, the laminated body is pressed and attached while being warped so that the surface (lower surface) of the polarizing plate 200 becomes a convex surface and the surface (upper surface) opposite to the attachment surface of the polarizing plate in the liquid crystal panel 100 becomes a concave surface. Can be matched. As a result, the stress between the liquid crystal panel 100 and the polarizing plate 200 of the laminated body 300 can be controlled, and the shape of the laminated body 300 after being attached is not warped as shown in FIG. 5A, but is warped. The direction of is the same as that of FIG. 5 (a) while reducing the warp, the shape is made without warp as shown in FIG. 5 (b), and the warp in the opposite direction is made as shown in FIG. 5 (c). Can be given.

Specifically, the warp of the laminated body 300 after being attached can be controlled by adjusting the amount of warp of the laminated body 300 in the pressing step between the pair of nip rolls 21 and 22 in FIG. For example, the higher the warpage is, the lower H1min is than H2 and H3, the more the mode as shown in FIG. 5 (a), the mode as shown in FIG. 5 (b), and the mode shown in FIG. 5 (c). It is possible to shift to such an embodiment in order.

The present invention is not limited to the above embodiment, and various modifications can be implemented.

For example, the rotation shafts 21a and 22a of the pair of nip rolls 21 and 22 do not have to be parallel to the lateral direction of the rectangle of the liquid crystal panel 100 at the time of attachment, and may be parallel to the longitudinal direction of the rectangle. It may be in the lateral direction and the diagonal direction.

Further, in the above embodiment, the transmission axis of the sticking polarizing plate 200 is parallel to the rotation axes 21a and 22a of the pair of nip rolls 21 and 22, but the direction of the transmission axis is arbitrary and the pair. The nip rolls 21 and 22 may be perpendicular to the rotation shafts 21a and 22a, and can be implemented in an oblique direction.

Further, as the horizontal transport means, for example, a belt conveyor other than the roller conveyor may be used.

Further, in the above embodiment, as shown in FIG. 4, the height H1 is different from the heights H2 and H3 when the laminated body is not instructed by both the upstream roller conveyor and the downstream roller conveyor. However, if the difference between H1 and H2 and H3 is small, it can be carried out even if H1 is fixed in a state different from that of H2 and H3.

Further, although the above embodiment describes the case where the polarizing plate is attached to the TFT side of the liquid crystal panel, it can also be applied when the polarizing plate is attached to the color filter side of the liquid crystal panel.

Further, the shape of the liquid crystal panel does not have to be rectangular, and various shapes such as a circle and an ellipse can be used.

Further, in the above embodiment, the pre-cut laminate is attached on the long support film, and the polarizing plate is supplied so that the liquid crystal panel and the polarizing plate are pressed together with the support film. It may be supplied by other methods. For example, the laminate cut by a knife edge or the like may be peeled off from the support film and then attached to a polarizing plate and supplied between the pair of nip rolls.

Further, the polarizing plate is not particularly limited in the laminated structure as long as the polarizing element layer is included.

Further, although the liquid crystal panel is adopted as the optical display panel in the above embodiment, it can be applied to an optical display panel other than the liquid crystal panel, for example, an organic EL panel. The thickness, shape, and size of the optical display panel other than the liquid crystal panel can be the same as that of the liquid crystal panel.

The organic EL panel can have a first transparent substrate, an organic light emitting diode (OLED) layer, and a second transparent substrate. The first transparent substrate can be a substrate with a TFT.

Further, the optical film to be attached to the optical display panel is not limited to the linear polarizing plate, and a circular polarizing plate and an elliptical polarizing plate in which a retardation plate is laminated on the polarizing plate, a retardation plate, a brightness improving film, a compound refraction control film, and reflection. It can be applied to various films such as a polarizing film. Even when the optical film itself does not exhibit anisotropic shrinkage behavior, it is possible to control the warp after sticking by giving warp at the time of sticking.

Further, in the above embodiment, a pair of nip rolls 21 and 22 are used by using a warp imparting mechanism 5 having an upstream roller conveyor 10, a downstream roller conveyor 40, a pair of nip rolls 21 and 22, and a pair of nip roll positioning mechanisms 50. Is given a warp by moving it downward, but the method of giving a warp to the laminated body along the surface of the pair of nip rolls is not limited to this.

For example, in the pressing step, the height of the portion P sandwiched between the pair of nip rolls 21 and 22 in the laminated body 300 is set to the height H2 of the upper surface of the upstream roller conveyor 10 and the height H3 of the upper surface of the downstream roller conveyor 40. It is also possible to make the portion P of the laminated body 300 along the lower nip roll 22 by gravity.

Further, it can be carried out even when the optical display panel is transported diagonally instead of horizontally.

Further, in the above embodiment, the diameters of the pair of nip rolls 21 and 22 are different from each other, but the same diameter can be used. When the height H1 of the portion P is moved below the heights H2 and H3 to give a warp, it is preferable that the diameter of the upper nip roll is large, and the height H1 of the portion P is the height H2 and the height H2. When moving above H3 to give warpage, it is preferable that the diameter of the lower nip roll is large.

Further, instead of a horizontal transfer mechanism such as the upstream roller conveyor 10 and the downstream roller conveyor 40, which provide a large number of rolls, a single roller is arranged before and after the pair of nip rolls 21 and 22, to give warpage. Already good.

(Examples 1 to 6 and Comparative Example 1)
The liquid crystal panel and the polarizing plate were bonded using the bonding device shown in FIGS. 2 and 3.

Liquid crystal panel thickness 1.0 mm, rectangular long side 1660 mm, short side 950 mm

Laminated structure of polarizing plate Adhesive layer (thickness 20 μm) / TAC (thickness 60 μm) / PVA (thickness 20 μm) / TAC (thickness 60 μm)
Although TAC and PVA are bonded to each other via an adhesive layer, the description of the thickness of the adhesive layer is omitted.

The transmission axis of the polarizing plate was arranged parallel to the rotation axis of the nip roll, and the short side of the liquid crystal panel was arranged parallel to the rotation axis of the nip roll. A polarizing plate was attached to the side surface of the TFT of the liquid crystal panel.

Nip roll conditions The upper nip roll had a diameter of 100 mm, the lower nip roll had a diameter of 30 mm, and the nip roll was made of rubber.

Table 1 shows CV1, CV2, the bonding pressure by the pair of nip rolls, the bonding speed ratio, the presence or absence of the pair of nip rolls descending during bonding, and the amount of descending.
The bonding speed ratio means the ratio of the speed of the liquid crystal panel 100 to the speed of the polarizing plate 200.

Further, regarding the amount of descent of the height H1 during bonding, in FIG. 4, L1 = 250 mm, L2 = 350 mm, L3 = 1240 mm, and L4 = 1340 mm.

Table 1 shows the amount of warpage of the obtained laminate. Here, as shown in FIG. 6A, the laminated body 300 is placed on the horizontal plane S so that the convex side of the warp faces downward, and the short side A on the leading side of the bonding on the bottom surface of the laminated body 300 is set. In the state of being in contact with the horizontal plane S, the maximum lift amount of the short side B on the back side of the bonding on the bottom surface is measured as the head fixed warp amount of 400A, and as shown in FIG. 6B, the back of the bonding on the bottom surface. With the side short side B in contact with the horizontal plane S, the maximum amount of lift of the leading side short side A of the bonding on the bottom surface was measured as the back fixed warp amount of 400B. The warp when the color filter side surface 100CF of the liquid crystal panel 100 is convex as shown in FIG. 5 (a) is regarded as a positive warp, and the TFT side surface 100 TFT of the liquid crystal panel 100 is convex as shown in FIG. 5 (c). The case of warping so as to be is regarded as a negative warp.

According to the examples, it was confirmed that the amount and direction of warpage of the laminated body can be controlled.

1 ... Laminating device, 5 ... Warp applying mechanism, 10 ... Upstream roller conveyor (upstream horizontal transport means), 21 and 22 ... Nip rolls, 21a, 22a ... Rotating shaft, 100 ... Liquid crystal panel (optical display panel), 200 ... Polarizing plate (optical film), 300 ... Laminated body, 40 ... Downstream roller conveyor (downstream horizontal transport means), 50 ... Positioning mechanism, 60 ... Control unit, P ... Part, S ... Horizontal plane, A ... Leading side short Side, B ... Short side on the back side, 400A ... Fixed warp amount at the beginning, 400B ... Fixed warp amount at the back.

Claims (16)

A method for manufacturing a laminate having an optical display panel and an optical film.
A pressing step of pressing the laminate of the optical display panel and the optical film between a pair of rotating nip rolls is provided.
A method of giving a warp to the laminated body along the surface of one of the nip rolls in the pressing step. A step of transporting the optical display panel toward the pair of nip rolls by the upstream horizontal transport means, and
Further provided with a step of transporting the laminated body discharged from the pair of nip rolls by the downstream horizontal transport means.
The rotation axes of the pair of nip rolls are arranged vertically apart from each other.
In the pressing step, the height of the portion of the laminated body sandwiched between the pair of nip rolls is lower or higher than the height of the upper surface of the upstream horizontal transport means and the height of the upper surface of the downstream horizontal transport means. The method according to claim 1, wherein the laminated body is warped. The laminated body is not warped until the leading end portion in the flow direction of the laminated body reaches the top of the downstream horizontal transport means.
After the leading end portion of the laminated body in the flow direction reaches the top of the downstream horizontal transport means, the laminated body is given the warp.
The method according to claim 2, wherein the warp is eliminated while the rear end portion of the optical display panel in the flow direction is supported by the upper surface of the upstream horizontal transport means. The method according to claim 2 or 3, wherein the upstream horizontal transport means and the downstream horizontal transport means are roller conveyors, respectively. The method according to any one of claims 1 to 4, wherein the diameter of one nip roll is larger than the diameter of the other nip roll. The optical film is a polarizing plate, and in a laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate and the axes of the pair of nip rolls are arranged in parallel, claims 1 to 5. The method according to any one of the above. The surface of the optical display panel has a rectangular shape, and in the laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate and the lateral direction of the surface of the optical display panel are arranged in parallel. The method according to claim 6. The method according to claim 6 or 7, wherein the optical display panel is a liquid crystal panel, and the polarizing plate is attached to the TFT side of the liquid crystal panel. A pair of nip rolls that press the laminate of the optical display panel and the optical film,
A laminating device comprising a warp imparting mechanism that warps the laminated body along the surface of one of the nip rolls. The rotation axes of the pair of nip rolls are arranged vertically apart from each other.
The warp imparting mechanism is an upstream horizontal transport means for transporting an optical display panel to the pair of nip rolls.
A downstream horizontal transport means for transporting a laminate of the optical display panel and the optical film discharged from the pair of nip rolls, and
The height of the portion of the laminated body sandwiched between the pair of nip rolls is larger than the height of the laminated body transported by the upstream horizontal transport means and the height of the laminated body transported by the downstream horizontal transport means. 9. The apparatus of claim 9, further comprising a positioning mechanism that defines the position of the pair of nip rolls so that they are also low or high. Until the leading end of the laminated body in the flow direction reaches the top of the downstream horizontal transport means, the height of the portion of the laminated body sandwiched between the pair of nip rolls is set to the upstream horizontal transport means. Maintained at the same height as the height of the upper surface of the lower surface and the height of the upper surface of the downstream horizontal transport means.
After the leading end of the laminated body in the flow direction reaches the top of the downstream horizontal transport means, the height of the portion of the laminated body sandwiched between the pair of nip rolls is set to the height of the upstream horizontal transport means. The positions of the pair of nip rolls are changed with respect to the upstream horizontal transport means and the downstream horizontal transport means so as to be lower or higher than the height of the upper surface and the height of the upper surface of the downstream horizontal transport means.
While the rear end of the optical display panel in the flow direction is supported by the upper surface of the upstream horizontal transport means, the height of the portion of the laminated body sandwiched between the pair of nip rolls is set to the upstream horizontal. The device according to claim 10, further comprising a control unit that controls the positioning mechanism so as to return the height to the height of the upper surface of the transport means and the height of the upper surface of the downstream horizontal transport means. The device according to claim 10 or 11, wherein the upstream horizontal transport means and the downstream horizontal transport means are roller conveyors, respectively. The device according to any one of claims 9 to 12, wherein the diameter of one nip roll is larger than the diameter of the other nip roll. The optical film is a polarizing plate, and in a laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate and the axes of the pair of nip rolls are arranged in parallel, claims 9 to 13. The apparatus according to any one of the above. The surface of the optical display panel has a rectangular shape, and in the laminated body pressed between the nip rolls, the direction of the transmission axis of the polarizing plate and the lateral direction of the surface of the optical display panel are arranged in parallel. The device according to claim 14. The device according to claim 14 or 15, wherein the optical display panel is a liquid crystal panel, and the polarizing plate is attached to the TFT side of the liquid crystal panel.

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